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Genomics of Alzheimer Disease: A Review

Genomics of Alzheimer Disease: A Review Abstract Importance To provide a comprehensive review of knowledge of the genomics of Alzheimer disease (AD) and DNA amyloid β 42 (Aβ42) vaccination as a potential therapy. Observations Genotype-phenotype correlations of AD are presented to provide a comprehensive appreciation of the spectrum of disease causation. Alzheimer disease is caused in part by the overproduction and lack of clearance of Aβ protein. Oligomer Aβ, the most toxic species of Aβ, causes direct injury to neurons, accompanied by enhanced neuroinflammation, astrocytosis and gliosis, and eventually neuronal loss. The strongest genetic evidence supporting this hypothesis derives from mutations in the amyloid precursor protein (APP) gene. A detrimental APP mutation at the β-secretase cleavage site linked to early-onset AD found in a Swedish pedigree enhances Aβ production, in contrast to a beneficial mutation 2 residues away in APP that reduces Aβ production and protects against the onset of sporadic AD. A number of common variants associated with late-onset AD have been identified including apolipoprotein E, BIN1, ABC7, PICALM, MS4A4E/MS4A6A, CD2Ap, CD33, EPHA1, CLU, CR1, and SORL1. One or 2 copies of the apolipoprotein E ε4 allele are a major risk factor for late-onset AD. With DNA Aβ42 vaccination, a Th2-type noninflammatory immune response was achieved with a downregulation of Aβ42-specific effector (Th1, Th17, and Th2) cell responses at later immunization times. DNA Aβ42 vaccination upregulated T regulator cells (CD4+, CD25+, and FoxP3+) and its cytokine interleukin 10, resulting in downregulation of T effectors. Conclusions and Relevance Mutations in APP and PS-1 and PS-2 genes that are associated with early-onset, autosomal, dominantly inherited AD, in addition to the at-risk gene polymorphisms responsible for late-onset AD, all indicate a direct and early role of Aβ in the pathogenesis of AD. A translational result of genomic research has been Aβ-reducing therapies including DNA Aβ42 vaccination as a promising approach to delay or prevent this disease. Introduction Alzheimer disease (AD) is characterized by 2 pathological hallmarks, amyloid β (Aβ) protein–containing neuritic plaques and hyperphosphorylated tau-containing paired helical filament in neurofibrillary tangles.1 Amyloid β protein is generated by sequential cleavages of the amyloid precursor protein (APP) by β- and γ-secretases. First, APP is proteolytically processed by β-secretase and generates a 12-kDa C-terminal stub of the APP gene (C99); second, C99 is cleaved by γ-secretase to yield 2 major species of Aβ ending at residue 40 (Aβ40) or residue 42 (Aβ42).2,3 Multiple mutations in the gene encoding APP cause early-onset familial AD, and most of them either lead to an increase in Aβ production or in the ratio of Aβ42 to Aβ40, thus enhancing the aggregation of Aβ peptides. Compared with shorter Aβ peptides, such as Aβ40 and Aβ38, many studies have documented that the 42-residue Aβ42 enhances aggregation propensity,4 leading to accelerated formation of small (low-n) Aβ oligomers.5 Mutations in presenilin genes have similar effect in increasing the ratio of Aβ42 to Aβ40. Cells bearing familial AD mutant genes (APP or PS1/2) produced higher levels of Aβ oligomers,6 which were observed in plasma and postmortem brains of patients with AD.7 Mutation in the tau gene causes frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17).8 In mice, Aβ accumulation can drive tau pathology in vivo.9 Transgenic mice expressing mutant tau show close association between tau mutation, neurofibrillary tangle formation, and neurodegeneration.10,11 Tau protein has been used as a marker for axonal damage, and tau levels in cerebrospinal fluids reflect these changes in the central nervous system. Tau protein levels (total tau, phosphorylated tau, and the ratio) in cerebrospinal fluid have been explored as potential markers for AD. Translational genomic research has developed potential DNA Aβ42 therapeutics for AD. A noninflammatory Th2-mediated immune response with effective levels of anti-Aβ42 antibody has been developed in transgenic AD model mice with the DNA Aβ42 vaccine and is included as a direct extension of advances in AD genomics. Box Section Ref ID Key Points Question What is the current genomic understanding of amyloid β protein–directed therapies for Alzheimer disease? Findings In this review, mutations associated with Alzheimer disease, polymorphisms increasing risk, and amyloid β protein–reducing therapies are defined. The magnitude of defining the genomic and epigenomic factors involved in the pathogenesis of Alzheimer disease and new therapeutic strategies as a result are large in number and complexity. Meaning Effective therapy to delay or prevent Alzheimer disease may be based on a defined genomic understanding. Amyloid Cascade Hypothesis Mechanisms for AD pathogenesis have been extensively explored, and the major hypothesis supported by genetic and neuropathological evidences is the amyloid cascade hypothesis.12 It suggests that AD is caused in part by the overproduction and lack of clearance of Aβ. The most toxic species of Aβ, such as oligomer Aβ, cause direct injury to neurons, accompanied by enhanced neuroinflammation, astrocytosis and gliosis, and eventually neuronal loss. The strongest genetic evidence supporting this hypothesis derives from mutations in the APP gene. A detrimental APP mutation at the β-secretase cleavage site (the APP KM670/671NL mutation), linked to early-onset AD found in a Swedish pedigree, enhances Aβ production,13 in contrast to a beneficial mutation 2 residues away (Icelandic mutation A673T) in APP that reduces Aβ production and protects against the onset of sporadic AD.14 The Swedish mutant APP is a better substrate for recognition and cleavage by the β-secretase, while the Icelandic mutant APP is a much poorer substrate for the β-secretase,14 and the Icelandic mutation greatly attenuates APP–β-secretase interaction.15 The amyloid cascade hypothesis is also supported by additional genetic studies with the other 2 genes associated with early-onset familial AD, the presenilin 1 and 2 genes (PS1 and PS2). To our knowledge, only 3 genes have been identified to associate with familial AD, and all of them encode the key components of the Aβ synthesis pathway. The APP gene encodes the precursor of Aβ and is the substrate of the γ-secretase, and PS1 and PS2 genes encode the proteins that carry the active site of the γ-secretase.16 γ-Secretase is composed of PS1 (or PS2), presenilin enhancer-2, anterior pharynx defective-1, and nicastrin.17-19PS1 itself has proteolytic activity,20,21 which is activated by presenilin enhancer-2.20,22 Nicastrin is the substrate receptor for APP.23 A number of mutations in APP13 or PS1/26,24,25 that link to familial AD affect the γ-secretase cleavage of APP and shift Aβ production from Aβ40 to the more toxic and aggregation-prone Aβ42. Mutations that provide more copies of APP genelike duplications26 and Down syndrome27 generate more Aβ in the brains of those patients. Almost all pathogenic mutations found in the APP gene lead to increased generation of Aβ or the Aβ42 to Aβ40 ratio because Aβ42 is more toxic than Aβ40. The Swedish mutation at the β-secretase cleavage site allows APP to be more accessible to the enzyme and generates more Aβ.13,28 The Arctic mutation of APP (APP E693G) increases the aggregation propensity of Aβ and fibril formation.29 Pathogenic V717F, V717I, and V717L mutations all increase the Aβ42/Aβ40 ratio.30-32 Major AD Risk Genes and Their Involvement in Aβ Metabolism A number of common variants associated with late-onset AD have been identified, including apolipoprotein E (APOE), BIN1, ABCA7, PICALM, MS4A4E/MS4A6A, CD2AP, CD33, EPHA1, CLU, CR1, and SORL1.33-36 One or 2 copies of the APOE ε4 allele is a major risk factor for late-onset AD (LOAD).37,38 The APOE gene has 3 major isoforms, APOE ε2, ε3, and ε4. Brains of patients with sporadic AD carrying the APOE ε4 allele were found to have increased density of Aβ deposits, limited capability to clear Aβ, and enhanced neuroinflammation.39 Binding of APOE loaded with Aβ to cell surface receptors, such as the low-density lipoprotein receptor-related protein-1 (LRP1), is one of the mechanisms for Aβ clearance.40,41 Clusterin (encoded by CLU) directly interacts with soluble Aβ and forms a complex to cross the blood-brain barrier.42 This function is similar to APOE, which acts as a molecular chaperone for Aβ. Both clusterin and APOE directly influence Aβ during its aggregation and deposition. The presence of APOE/clusterin changes Aβ conformation and its toxicity.43,44 Therefore, APOE and clusterin may regulate the conversion of soluble Aβ into insoluble forms such as oligomers, thus suppressing Aβ toxicity and deposition. Because APOE and clusterin are involved in a complex formation with Aβ to cross the blood-brain barrier, both proteins regulate Aβ clearance.45 Alternative pathways for Aβ clearance are mediated by microglia. When extracellular Aβ aggregates, such as Aβ, are engulfed by microglia, inflammasomes (such as NOD-like receptor family pyrin domain-containing 3 [NLRP3]) are triggered, which activate caspases and promote interleukin 1β release.46,47 These aggregates are known to activate innate immune responses via complement pathways, including complement receptor 1 (CR1), which has been associated with LOAD.48 Those Aβ isoforms that bind to scavenger receptors expressed on microglia, such as CD3649 and Scara1,50 enter microglia and activate inflammation. Systems analysis of hundreds of brains with AD reveals changes in networks related to immunologic molecules and microglial cells including microglial protein TYROBP, which binds the microglial receptor TREM2 (triggering receptors expressed on myeloid cells 2) and may regulate CD33 function.51 Genetic mutations found in TREM2 triple a person’s risk for AD52,53 and increased expression of CD33, which functions to suppress Aβ uptake and clearance.54,55 Another transporter protein associated with LOAD is ATP-binding cassette transporter (ABCA7), which belongs to the ATP-binding cassette transporter superfamily that transports many substrates across cell membranes. The ABCA7 gene is involved in the efflux of lipids from cells to lipoprotein particles. In an APP transgenic mouse model (J20) that is deficient in ABCA7, levels of APOE were not changed.56 However, both soluble and insoluble Aβ levels and thioflavine-S–positive plaques were increased in the ABCA7-deficient mice.56,57 In cultured cells, enhanced endocytosis of APP was observed in ABCA7 knockout cells, leading to increased Aβ production.57 Phosphatidylinositol-binding clathrin assembly protein (PICALM) plays a critical role in clathrin-mediated endocytosis and protein/lipid internalization.33 When full-length APP at the cell surface is internalized by clathrin-mediated endocytosis, β- and γ-secretase cleavages occur, and a significant amount of Aβ is generated.58 When endocytosis is promoted by increased synaptic activity, more APP is retrieved from the cell surface to endosomes, resulting in an increase of Aβ generation and secretion.59 Involvement of PICALM with clathrin-mediated endocytosis directly affects APP processing and Aβ synthesis. Bridging integrator 1 (BIN1) is highly expressed in brain, and all BIN1 isoforms interact with clusterin and are involved in surface protein endocytosis. While it is possible that BIN1 influences APP endocytosis and Aβ production, its functional interaction with tau was demonstrated in a drosophila model where knockdown of the BIN1 ortholog Amph could suppress the rough eye phenotype caused by overexpression of human tau.60 Genetic variants in the sortilin-related receptor SORL1 gene are associated with LOAD.61 Reduction of SORL1 expression was observed in vulnerable regions in brains with AD.62,63 In cultured cells, SORL1 interacts with APP and both proteins colocalize in endosomal and Golgi compartments.61,63 They also interact with vacuolar protein sorting-associated protein 35 (VPS35); VPS35 promotes cargo selection in the retromer through SORL1. When expression of SORL1 is increased, SORL1 regulates differential sorting of APP into the retromer recycling pathway, thus reducing Aβ production; when expression of SORL1 is reduced, APP trafficking is directed toward endosome-lysosome compartments that facilitate Aβ production.61 Deficient SORL1 expression in knockout mice resulted in increased levels of Aβ in animal brains.62,63 The PCDH11X gene is a cell surface receptor molecule belonging to the protocadherin gene, which is a subfamily of the cadherin superfamily. Like other cadherins, it mediates cell-cell adhesion and is cleaved by γ-secretase.64 Cadherins, such as E- and N-cadherins, form the complex with PS1/γ-secretase65 and regulate cell-cell interaction after the cleavage by γ-secretase; this process is inhibited by familial AD mutations in PS1.66 Therefore, PCDH11X is believed to play a role in cell signaling that is critical in the development of the central nervous system.67 Genetic variation in PCDH11X is associated with LOAD.68 The MS4A4E/MS4A6A genes belong to the MS4A gene cluster on chromosome 11. The proteins encoded by these similar genes have a common transmembrane domain and likely are cell surface proteins. Their involvement in Aβ production is not known. The EPHA1 gene is a member of the ephrin receptor family. Both ephrins and Eph receptors play important roles in cell and axon guidance, and another member of this family, EphA4, is cleaved by γ-secretase induced by synaptic activity.69 The CD2-associated protein (CD2AP) is a scaffold/adaptor protein and mediates receptor-regulated endocytosis.70 In cultured cells, reducing CD2AP expression results in decreased levels of Aβ and a lower Aβ42/Aβ40 ratio. Knockout of CD2AP in transgenic mice overexpressing PS1 and APP (PS1APP mice) decreased the Aβ42/Aβ40 ratio in the brain; expressing 1 copy of CD2APP in PS1APP mice does not affect Aβ deposition.71 Imbalanced Aβ homeostasis, ie, increased Aβ production and/or decreased Aβ clearance, is an upstream event of neurodegeneration that is directly affected by AD risk gene products (Figure 1). The SORL1, PICALM, and CD2AP genes are involved in endocytic internalization of cell surface APP for β- and γ-secretase cleavages to generate Aβ, while APOE, CLU, TREM2, ABCA7, PICALM, CD33, CD2AP, and CR1 are all involved in Aβ clearance through multiple mechanisms. These risk genes, in addition to familial AD–linked mutant genes APP, PS1, and PS2, all point to the direct and early role of Aβ in the pathogenesis of AD. Amyloid-β–reducing therapies, including DNA Aβ42 vaccination, have a therapeutic potential to delay or prevent the disease (Table). DNA and Peptide Aβ42 Vaccination: Translational Therapy From Genomics The amyloid cascade hypothesis postulates that Aβ deposition in the brain is a primary event necessary in the multifactoral pathogenesis of AD.12,89,90 It has been demonstrated that Aβ deposition precedes AD symptoms by at least 20 years.91 Therapeutic approaches using active and passive immunizations against Aβ have a high possibility to be effective in removing amyloid from the brain and thereby delaying or preventing downstream pathologies. Since 2000, a number of clinical trials for AD immunotherapy have started, have failed, and are continuing.92-99 Amyloid β protein at resiude 42 peptide vaccination with adjuvant in the clinical trial AN179292,93,99 resulted in an autoimmune meningoencephalitis with T cells infiltrating the brain of affected vaccinated patients, and the study was stopped. A clinical trial94,100 with the monoclonal antiamyloid antibody bapineuzumab reduced the level of amyloid accumulation as seen by amyloid imaging but had no clinical benefit in patients expressing clinical signs of AD. New studies started between 2013 and 2015 focus on therapy in patient cohorts before the onset of clinical symptoms of AD.101 These include the Dominantly Inherited Alzheimer Network study,102 the Alzheimer Prevention Initiative, and the Treatment of Asymptomatic Alzheimer.103 A major achievement will occur if passive Aβ immunotherapy for AD can be shown to have clinical benefit. If and when these new prevention studies using passive immunizations with anti-Aβ antibodies provide clinical benefit by delaying or preventing AD, active vaccination, potentially with a DNA Aβ42 vaccine, will increase in interest because it induces an effective and noninflammatory immune response and is applied more efficiently and economically to large populations. A translational result of genomic research has been the development of immunization, with a full-length DNA Aβ42 plasmid in mice generating a polyclonal multivalent vaccine.104 Studies in outbreed animals, such as rabbits and dogs, have shown that the immune response to fibrillar Aβ is diverse and reflects the polymorphic structure of the antigen itself. These studies also lead to the conclusion that single therapeutic monoclonal antibodies with 1 specific epitope may not be able to target all the different aggregates to have an effect on diminishing disease progression.105,106 We have developed an Aβ42 plasmid encoding 3 copies of the full-length Aβ42 sequence. Transcription of Aβ42 is initiated by the transcription factor Gal4, which is encoded by a second plasmid that is delivered simultaneously by cotransfection (Figure 2). This approach had been shown to increase the expression of the Aβ42 sequence without causing Aβ42 cytotoxicity in the transfected cells.107 Immunization with Aβ1-42 is strongly influenced by the fact that this is a self-antigen, and tolerance against self-antigens has to be broken. In wild-type mice, human Aβ42 is a foreign antigen owing to 3 amino acid alterations in the N-terminal segment of the peptide, and wild-type mice produce high levels of anti-Aβ antibodies following immunization. Higher levels of antibody produced in the wild-type mouse are owing to the fact that the DNA in the plasmid coding for Aβ42 peptide is of human type. This explains the differences in the comparison of the antibody responses in wild-type mice and human APP transgenic mice. As in the APP transgenic mouse receiving the DNA Aβ42 plasmid, the expressed Aβ42 peptide in the brain and in the vaccinated skin cells is both of human type. The eFigure in the Supplement shows the analysis of double transgenic and wild-type mice that have been immunized 9 times with the DNA Aβ42 vaccine via gene gun administration. The wild-type mice in this group reached antibody levels with a mean (SD) of 63 (18.16) μg/mL of plasma and the transgenic mice had antibody levels with a mean (SD) of 13.51 (9.18) μg/mL of plasma (P < .001). In AD mouse models, we have demonstrated up to a 50% reduction in brain amyloid following full-length DNA Aβ42 vaccination.108-110 In Figure 3, the results shown were from 2 double transgenic mouse cohorts, from which amyloid levels in the brain had been analyzed 2 weeks following the last immunization (Figure 3A) or 4 months after the last immunization (Figure 3B). Group A showed an amyloid reduction of 65% and group B showed a reduction of Aβ1-42 brain levels of 25%. In both groups, the amyloid reduction was substantial in comparison with the control DNA (Luc)–immunized mice (Mann-Whitney test: P = .006 and P = .007, respectively). The marked difference between these 2 groups is explained by the time differences between final immunizations and brain level analyses (14 days and 4 months following the last immunization; 12 and 16 months of age) and the marked differences in total Aβ42 levels in the brain owing to the 4-month age difference between groups A and B. Concentration of Aβ42 in the brain increased from 10 μg/g wet tissue to 50 μg/g in the Luc control mice owing to increased AD pathology with the age progression in these mice. With DNA Aβ42 vaccination, a Th2-type noninflammatory immune response was achieved, with a downregulation of Aβ42-specific T effector (Th1, Th17, and Th2) cell responses at later immunization times.111-116 On the other hand, DNA Aβ42 vaccination upregulated T regulator cells (CD4+, CD25+, and FoxP3+) and the cytokine interleukin 10, resulting in downregulation of T effectors. In distinction, Aβ42 peptide vaccination induced the opposite effect, with upregulation of T effectors (CD4+, CD25+, and FoxP3-) and no effect on T regulator cells. Thus, the immune response following DNA immunization differs quantitatively and qualitatively from the immune response elicited by Aβ42 peptide immunization. DNA Aβ42 immunization with downregulation of T effectors (Th1, Th17, and Th2 cells) would significantly reduce the opportunity for cytotoxic T cells from migrating and transiting through brain, which was evident in the Aβ42 peptide vaccine clinical trial AN1792, resulting in meningoencephalitis.92,115 Immunizations of 16 New Zealand white rabbits produced after 5 vaccinations anti-Aβ42 antibodies at mean levels of 250 µg/mL of serum. The isotyping of the serum antibody showed IgG, IgM, and IgA anti-Aβ42 antibodies. In autopsies of 9 rabbits, there was no evidence of meningoencephalitis. Immunizations of 6 rhesus monkeys produced after 4 vaccinations of anti-Aβ42 antibodies at mean levels of 112.6 µg/mL of serum and they have remained healthy with no adverse effects (D.L.-W. and R.N.R., preliminary unpublished observations). Conclusions Research into the genetics and genomics of AD has made major strides in the past decade. The PS1, PS2, and APP gene mutations have been documented to result in aggressive, early-onset autosomal dominant disease. Polymorphisms in multiple genes have been shown to increase the risk for the disease. A polymorphism in the APP gene, preventing binding of β-secretase to APP in APOE4 persons and impairing production of Aβ42 peptide being processed from the parent APP molecule, prevents the clinical expression of AD and is in strong support of the amyloid cascade hypothesis. Amyloid imaging has provided the accurate means to identify asymptomatic at-risk persons accumulating amyloid to test antiamyloid therapies.117 Active vaccination with a DNA Aβ42 vaccine offers a potential effective and noninflammatory approach and is one of several active vaccination approaches after demonstration of clinical benefit from passive antiamyloid antibody therapy.118 The magnitude of defining the genomic and epigenomic factors involved in the pathogenesis of AD and new therapeutic strategies that will occur as a result are large in number and complexity. The Human Alzheimer Disease Project, an undertaking at the level of commitment and funding equivalent to the Human Genome Project, is necessary and required to stem the crescendo of anticipated increases in the prevalence of this disease in the foreseeable future.119 Section Editor: David E. Pleasure, MD. Back to top Article Information Corresponding Author: Roger N. Rosenberg, MD, University of Texas Southwestern Medical Center, Department of Neurology and Neurotherapeutics, Dallas, TX 75390 (roger.rosenberg@utsouthwestern.edu). Accepted for Publication: January 22, 2016. Published Online: May 2, 2016. doi:10.1001/jamaneurol.2016.0301. Author Contributions: Dr Rosenberg had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Each of the authors has provided ideas and concepts and has contributed to the writing of the manuscript. Study concept and design: Rosenberg, Yu, Xia. Acquisition, analysis, or interpretation of data: Labracht-Washington. Drafting of the manuscript: Rosenberg, Xia. Critical revision of the manuscript for important intellectual content: All authors. Obtained funding: Xia. Study supervision: Xia. Conflict of Interest Disclosures: Dr Rosenberg is director of the Alzheimer’s Disease Center at the University of Texas Southwestern Medical Center at Dallas. He received a US patent for “Amyloid β Gene Vaccines” in 2009. Funding/Support: Dr Rosenberg is principal investigator of the National Institutes of Health/National Institute on Aging grant P30AG12300-16. He receives funding from the Rudman Partnership, AWARE Group in Dallas, Freiberger Family Fund, McCune/Losinger Fund, Presbyterian Foundation, North Foundation, the Darryl K Royal Foundation, and the Zale Foundation. Dr Xia received funding from award I21BX002215 from the Biomedical Laboratory Research and Development Service of the Veterans Affairs Office of Research and Development. Role of the Funder/Sponsor: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. Disclaimer: Dr Rosenberg is the Editor of JAMA Neurology but was not involved in the editorial review or the decision to accept the manuscript for publication.The views expressed in this article are those of the authors and do not represent the views of the US Department of Veterans Affairs or the US Government. References 1. Selkoe DJ; American College of Physicians; American Physiological Society. Alzheimer disease: mechanistic understanding predicts novel therapies. Ann Intern Med. 2004;140(8):627-638.PubMedGoogle ScholarCrossref 2. Haass C, Schlossmacher MG, Hung AY, et al. Amyloid beta-peptide is produced by cultured cells during normal metabolism. Nature. 1992;359(6393):322-325.PubMedGoogle ScholarCrossref 3. Shoji M, Golde TE, Ghiso J, et al. Production of the Alzheimer amyloid beta protein by normal proteolytic processing. Science. 1992;258(5079):126-129.PubMedGoogle ScholarCrossref 4. Jarrett JT, Berger EP, Lansbury PT Jr. The carboxy terminus of the beta amyloid protein is critical for the seeding of amyloid formation: implications for the pathogenesis of Alzheimer’s disease. Biochemistry. 1993;32(18):4693-4697.PubMedGoogle ScholarCrossref 5. Walsh DM, Selkoe DJ. Deciphering the molecular basis of memory failure in Alzheimer’s disease. Neuron. 2004;44(1):181-193.PubMedGoogle ScholarCrossref 6. Xia W, Zhang J, Kholodenko D, et al. Enhanced production and oligomerization of the 42-residue amyloid beta-protein by Chinese hamster ovary cells stably expressing mutant presenilins. J Biol Chem. 1997;272(12):7977-7982.PubMedGoogle ScholarCrossref 7. Xia W, Yang T, Shankar G, et al. A specific enzyme-linked immunosorbent assay for measuring beta-amyloid protein oligomers in human plasma and brain tissue of patients with Alzheimer disease. Arch Neurol. 2009;66(2):190-199.PubMedGoogle ScholarCrossref 8. Hutton M. Molecular genetics of chromosome 17 tauopathies. Ann N Y Acad Sci. 2000;920:63-73.PubMedGoogle ScholarCrossref 9. Lee VM, Trojanowski JQ. Progress from Alzheimer’s tangles to pathological tau points towards more effective therapies now. J Alzheimers Dis. 2006;9(3)(suppl):257-262.PubMedGoogle Scholar 10. Lewis J, McGowan E, Rockwood J, et al. Neurofibrillary tangles, amyotrophy, and progressive motor disturbance in mice expressing mutant (P301L) tau protein. Nat Genet. 2000;25(4):402-405.PubMedGoogle ScholarCrossref 11. Götz J, Chen F, van Dorpe J, Nitsch RM. Formation of neurofibrillary tangles in P301l tau transgenic mice induced by Abeta 42 fibrils. Science. 2001;293(5534):1491-1495.PubMedGoogle ScholarCrossref 12. Hardy J, Selkoe DJ. The amyloid hypothesis of Alzheimer’s disease: progress and problems on the road to therapeutics. Science. 2002;297(5580):353-356.PubMedGoogle ScholarCrossref 13. Citron M, Oltersdorf T, Haass C, et al. Mutation of the beta-amyloid precursor protein in familial Alzheimer’s disease increases beta-protein production. Nature. 1992;360(6405):672-674.PubMedGoogle ScholarCrossref 14. Jonsson T, Atwal JK, Steinberg S, et al. A mutation in APP protects against Alzheimer’s disease and age-related cognitive decline. Nature. 2012;488(7409):96-99.PubMedGoogle ScholarCrossref 15. Das U, Wang L, Ganguly A, et al. Visualizing APP and BACE-1 approximation in neurons yields insight into the amyloidogenic pathway. Nat Neurosci. 2016;19(1):55-64.PubMedGoogle ScholarCrossref 16. Wolfe MS, Xia W, Ostaszewski BL, Diehl TS, Kimberly WT, Selkoe DJ. Two transmembrane aspartates in presenilin-1 required for presenilin endoproteolysis and gamma-secretase activity. Nature. 1999;398(6727):513-517.PubMedGoogle ScholarCrossref 17. Sherrington R, Rogaev EI, Liang Y, et al. Cloning of a gene bearing missense mutations in early-onset familial Alzheimer’s disease. Nature. 1995;375(6534):754-760.PubMedGoogle ScholarCrossref 18. Francis R, McGrath G, Zhang J, et al. aph-1 And pen-2 are required for Notch pathway signaling, gamma-secretase cleavage of betaAPP, and presenilin protein accumulation. Dev Cell. 2002;3(1):85-97.PubMedGoogle ScholarCrossref 19. Yu G, Nishimura M, Arawaka S, et al. Nicastrin modulates presenilin-mediated notch/glp-1 signal transduction and betaAPP processing. Nature. 2000;407(6800):48-54.PubMedGoogle ScholarCrossref 20. Ahn K, Shelton CC, Tian Y, et al. Activation and intrinsic gamma-secretase activity of presenilin 1. Proc Natl Acad Sci U S A. 2010;107(50):21435-21440.PubMedGoogle ScholarCrossref 21. Lessard CB, Wagner SL, Koo EH. And four equals one: presenilin takes the gamma-secretase role by itself. Proc Natl Acad Sci U S A. 2010;107(50):21236-21237.PubMedGoogle ScholarCrossref 22. Li YM, Xu M, Lai MT, et al. Photoactivated gamma-secretase inhibitors directed to the active site covalently label presenilin 1. Nature. 2000;405(6787):689-694.PubMedGoogle ScholarCrossref 23. Shah S, Lee SF, Tabuchi K, et al. Nicastrin functions as a gamma-secretase-substrate receptor. Cell. 2005;122(3):435-447.PubMedGoogle ScholarCrossref 24. Citron M, Westaway D, Xia W, et al. Mutant presenilins of Alzheimer’s disease increase production of 42-residue amyloid beta-protein in both transfected cells and transgenic mice. Nat Med. 1997;3(1):67-72.PubMedGoogle ScholarCrossref 25. Scheuner D, Eckman C, Jensen M, et al. Secreted amyloid beta-protein similar to that in the senile plaques of Alzheimer’s disease is increased in vivo by the presenilin 1 and 2 and APP mutations linked to familial Alzheimer’s disease. Nat Med. 1996;2(8):864-870.PubMedGoogle ScholarCrossref 26. Rovelet-Lecrux A, Hannequin D, Raux G, et al. APP locus duplication causes autosomal dominant early-onset Alzheimer disease with cerebral amyloid angiopathy. Nat Genet. 2006;38(1):24-26.PubMedGoogle ScholarCrossref 27. Wisniewski KE, Wisniewski HM, Wen GY. Occurrence of neuropathological changes and dementia of Alzheimer’s disease in Down’s syndrome. Ann Neurol. 1985;17(3):278-282.PubMedGoogle ScholarCrossref 28. Haass C, Lemere CA, Capell A, et al. The Swedish mutation causes early-onset Alzheimer’s disease by beta-secretase cleavage within the secretory pathway. Nat Med. 1995;1(12):1291-1296.PubMedGoogle ScholarCrossref 29. Nilsberth C, Westlind-Danielsson A, Eckman CB, et al. The “Arctic” APP mutation (E693G) causes Alzheimer’s disease by enhanced Abeta protofibril formation. Nat Neurosci. 2001;4(9):887-893.PubMedGoogle ScholarCrossref 30. Goate A, Chartier-Harlin M-C, Mullan M, et al. Segregation of a missense mutation in the amyloid precursor protein gene with familial Alzheimer’s disease. Nature. 1991;349(6311):704-706.PubMedGoogle ScholarCrossref 31. Murrell JR, Hake AM, Quaid KA, Farlow MR, Ghetti B. Early-onset Alzheimer disease caused by a new mutation (V717L) in the amyloid precursor protein gene. Arch Neurol. 2000;57(6):885-887.PubMedGoogle ScholarCrossref 32. Murrell J, Farlow M, Ghetti B, Benson MD. A mutation in the amyloid precursor protein associated with hereditary Alzheimer’s disease. Science. 1991;254(5028):97-99.PubMedGoogle ScholarCrossref 33. Harold D, Abraham R, Hollingworth P, et al. Genome-wide association study identifies variants at CLU and PICALM associated with Alzheimer’s disease [published correction appears in Nat Genet. 2013;45(6):712]. Nat Genet. 2009;41(10):1088-1093.PubMedGoogle ScholarCrossref 34. Naj AC, Jun G, Beecham GW, et al. Common variants at MS4A4/MS4A6E, CD2AP, CD33 and EPHA1 are associated with late-onset Alzheimer’s disease. Nat Genet. 2011;43(5):436-441.PubMedGoogle ScholarCrossref 35. Hollingworth P, Harold D, Sims R, et al; Alzheimer’s Disease Neuroimaging Initiative; CHARGE consortium; EADI1 consortium. Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33, and CD2AP are associated with Alzheimer’s disease. Nat Genet. 2011;43(5):429-435.PubMedGoogle ScholarCrossref 36. Lambert JC, Heath S, Even G, et al; European Alzheimer’s Disease Initiative Investigators. Genome-wide association study identifies variants at CLU and CR1 associated with Alzheimer’s disease. Nat Genet. 2009;41(10):1094-1099.PubMedGoogle ScholarCrossref 37. Strittmatter WJ, Saunders AM, Schmechel D, et al. Apolipoprotein E: high-avidity binding to beta-amyloid and increased frequency of type 4 allele in late-onset familial Alzheimer disease. Proc Natl Acad Sci U S A. 1993;90(5):1977-1981.PubMedGoogle ScholarCrossref 38. Rebeck GW, Reiter JS, Strickland DK, Hyman BT. Apolipoprotein E in sporadic Alzheimer’s disease: allelic variation and receptor interactions. Neuron. 1993;11(4):575-580.PubMedGoogle ScholarCrossref 39. Castellano JM, Kim J, Stewart FR, et al. Human apoE isoforms differentially regulate brain amyloid-β peptide clearance. Sci Transl Med. 2011;3(89):89ra57.PubMedGoogle ScholarCrossref 40. Sagare A, Deane R, Bell RD, et al. Clearance of amyloid-beta by circulating lipoprotein receptors. Nat Med. 2007;13(9):1029-1031.PubMedGoogle ScholarCrossref 41. Deane R, Wu Z, Sagare A, et al. LRP/amyloid beta-peptide interaction mediates differential brain efflux of Abeta isoforms. Neuron. 2004;43(3):333-344.PubMedGoogle ScholarCrossref 42. Zlokovic BV, Martel CL, Matsubara E, et al. Glycoprotein 330/megalin: probable role in receptor-mediated transport of apolipoprotein J alone and in a complex with Alzheimer disease amyloid beta at the blood-brain and blood-cerebrospinal fluid barriers. Proc Natl Acad Sci U S A. 1996;93(9):4229-4234.PubMedGoogle ScholarCrossref 43. Ma J, Yee A, Brewer HB Jr, Das S, Potter H. Amyloid-associated proteins alpha 1-antichymotrypsin and apolipoprotein E promote assembly of Alzheimer beta-protein into filaments. Nature. 1994;372(6501):92-94.PubMedGoogle ScholarCrossref 44. DeMattos RB, O’dell MA, Parsadanian M, et al. Clusterin promotes amyloid plaque formation and is critical for neuritic toxicity in a mouse model of Alzheimer’s disease. Proc Natl Acad Sci U S A. 2002;99(16):10843-10848.PubMedGoogle ScholarCrossref 45. Bell RD, Sagare AP, Friedman AE, et al. Transport pathways for clearance of human Alzheimer’s amyloid beta-peptide and apolipoproteins E and J in the mouse central nervous system. J Cereb Blood Flow Metab. 2007;27(5):909-918.PubMedGoogle Scholar 46. Halle A, Hornung V, Petzold GC, et al. The NALP3 inflammasome is involved in the innate immune response to amyloid-beta. Nat Immunol. 2008;9(8):857-865.PubMedGoogle ScholarCrossref 47. Heneka MT, Kummer MP, Stutz A, et al. NLRP3 is activated in Alzheimer’s disease and contributes to pathology in APP/PS1 mice. Nature. 2013;493(7434):674-678.PubMedGoogle ScholarCrossref 48. Jun G, Naj AC, Beecham GW, et al; Alzheimer’s Disease Genetics Consortium. Meta-analysis confirms CR1, CLU, and PICALM as alzheimer disease risk loci and reveals interactions with APOE genotypes. Arch Neurol. 2010;67(12):1473-1484.PubMedGoogle ScholarCrossref 49. Sheedy FJ, Grebe A, Rayner KJ, et al. CD36 coordinates NLRP3 inflammasome activation by facilitating intracellular nucleation of soluble ligands into particulate ligands in sterile inflammation. Nat Immunol. 2013;14(8):812-820.PubMedGoogle ScholarCrossref 50. Frenkel D, Wilkinson K, Zhao L, et al. Scara1 deficiency impairs clearance of soluble amyloid-β by mononuclear phagocytes and accelerates Alzheimer’s-like disease progression. Nat Commun. 2013;4(2030):2030.PubMedGoogle Scholar 51. Zhang B, Gaiteri C, Bodea LG, et al. Integrated systems approach identifies genetic nodes and networks in late-onset Alzheimer’s disease. Cell. 2013;153(3):707-720.PubMedGoogle ScholarCrossref 52. Guerreiro R, Wojtas A, Bras J, et al; Alzheimer Genetic Analysis Group. TREM2 variants in Alzheimer’s disease. N Engl J Med. 2013;368(2):117-127.PubMedGoogle ScholarCrossref 53. Jonsson T, Stefansson H, Steinberg S, et al. Variant of TREM2 associated with the risk of Alzheimer’s disease. N Engl J Med. 2013;368(2):107-116.PubMedGoogle ScholarCrossref 54. Griciuc A, Serrano-Pozo A, Parrado AR, et al. Alzheimer’s disease risk gene CD33 inhibits microglial uptake of amyloid beta. Neuron. 2013;78(4):631-643.PubMedGoogle ScholarCrossref 55. Bradshaw EM, Chibnik LB, Keenan BT, et al; Alzheimer Disease Neuroimaging Initiative. CD33 Alzheimer’s disease locus: altered monocyte function and amyloid biology. Nat Neurosci. 2013;16(7):848-850.PubMedGoogle Scholar 56. Kim WS, Li H, Ruberu K, et al. Deletion of Abca7 increases cerebral amyloid-β accumulation in the J20 mouse model of Alzheimer’s disease. J Neurosci. 2013;33(10):4387-4394.PubMedGoogle ScholarCrossref 57. Satoh K, Abe-Dohmae S, Yokoyama S, St George-Hyslop P, Fraser PE. ATP-binding cassette transporter A7 (ABCA7) loss of function alters Alzheimer amyloid processing. J Biol Chem. 2015;290(40):24152-24165.PubMedGoogle ScholarCrossref 58. Perez RG, Squazzo SL, Koo EH. Enhanced release of amyloid beta-protein from codon 670/671 “Swedish” mutant beta-amyloid precursor protein occurs in both secretory and endocytic pathways. J Biol Chem. 1996;271(15):9100-9107.PubMedGoogle ScholarCrossref 59. Cirrito JR, Kang JE, Lee J, et al. Endocytosis is required for synaptic activity-dependent release of amyloid-beta in vivo. Neuron. 2008;58(1):42-51.PubMedGoogle ScholarCrossref 60. Chapuis J, Hansmannel F, Gistelinck M, et al; GERAD consortium. Increased expression of BIN1 mediates Alzheimer genetic risk by modulating tau pathology. Mol Psychiatry. 2013;18(11):1225-1234.PubMedGoogle ScholarCrossref 61. Rogaeva E, Meng Y, Lee JH, et al. The neuronal sortilin-related receptor SORL1 is genetically associated with Alzheimer disease. Nat Genet. 2007;39(2):168-177.PubMedGoogle ScholarCrossref 62. Offe K, Dodson SE, Shoemaker JT, et al. The lipoprotein receptor LR11 regulates amyloid beta production and amyloid precursor protein traffic in endosomal compartments. J Neurosci. 2006;26(5):1596-1603.PubMedGoogle ScholarCrossref 63. Andersen OM, Reiche J, Schmidt V, et al. Neuronal sorting protein-related receptor sorLA/LR11 regulates processing of the amyloid precursor protein. Proc Natl Acad Sci U S A. 2005;102(38):13461-13466.PubMedGoogle ScholarCrossref 64. Haas IG, Frank M, Véron N, Kemler R. Presenilin-dependent processing and nuclear function of gamma-protocadherins. J Biol Chem. 2005;280(10):9313-9319.PubMedGoogle ScholarCrossref 65. Georgakopoulos A, Marambaud P, Efthimiopoulos S, et al. Presenilin-1 forms complexes with the cadherin/catenin cell-cell adhesion system and is recruited to intercellular and synaptic contacts. Mol Cell. 1999;4(6):893-902.PubMedGoogle ScholarCrossref 66. Marambaud P, Wen PH, Dutt A, et al. A CBP binding transcriptional repressor produced by the PS1/epsilon-cleavage of N-cadherin is inhibited by PS1 FAD mutations. Cell. 2003;114(5):635-645.PubMedGoogle ScholarCrossref 67. Blanco P, Sargent CA, Boucher CA, Mitchell M, Affara NA. Conservation of PCDHX in mammals; expression of human X/Y genes predominantly in brain. Mamm Genome. 2000;11(10):906-914.PubMedGoogle ScholarCrossref 68. Carrasquillo MM, Zou F, Pankratz VS, et al. Genetic variation in PCDH11X is associated with susceptibility to late-onset Alzheimer’s disease. Nat Genet. 2009;41(2):192-198.PubMedGoogle ScholarCrossref 69. Inoue E, Deguchi-Tawarada M, Togawa A, et al. Synaptic activity prompts gamma-secretase-mediated cleavage of EphA4 and dendritic spine formation. J Cell Biol. 2009;185(3):551-564.PubMedGoogle ScholarCrossref 70. Lynch DK, Winata SC, Lyons RJ, et al. A Cortactin-CD2-associated protein (CD2AP) complex provides a novel link between epidermal growth factor receptor endocytosis and the actin cytoskeleton. J Biol Chem. 2003;278(24):21805-21813.PubMedGoogle ScholarCrossref 71. Liao F, Jiang H, Srivatsan S, et al. Effects of CD2-associated protein deficiency on amyloid-β in neuroblastoma cells and in an APP transgenic mouse model. Mol Neurodegener. 2015;10:12.PubMedGoogle ScholarCrossref 72. Mullan M, Crawford F, Axelman K, et al. A pathogenic mutation for probable Alzheimer’s disease in the APP gene at the N-terminus of beta-amyloid. Nat Genet. 1992;1(5):345-347.PubMedGoogle ScholarCrossref 73. Citron M, Oltersdorf T, Haass C, et al. Mutation of the beta-amyloid precursor protein in familial Alzheimer’s disease increases beta-protein production. Nature. 1992;360(6405):672-674.PubMedGoogle ScholarCrossref 74. Chen WT, Hong CJ, Lin YT, et al. Amyloid-beta (Aβ) D7H mutation increases oligomeric Aβ42 and alters properties of Aβ-zinc/copper assemblies. PLoS One. 2012;7(4):e35807.PubMedGoogle ScholarCrossref 75. Wakutani Y, Watanabe K, Adachi Y, et al. Novel amyloid precursor protein gene missense mutation (D678N) in probable familial Alzheimer’s disease. J Neurol Neurosurg Psychiatry. 2004;75(7):1039-1042.PubMedGoogle ScholarCrossref 76. Zhou L, Brouwers N, Benilova I, et al. Amyloid precursor protein mutation E682K at the alternative β-secretase cleavage β′-site increases Aβ generation. EMBO Mol Med. 2011;3(5):291-302.PubMedGoogle ScholarCrossref 77. Kaden D, Harmeier A, Weise C, et al. Novel APP/Aβ mutation K16N produces highly toxic heteromeric Aβ oligomers. EMBO Mol Med. 2012;4(7):647-659.PubMedGoogle ScholarCrossref 78. Hendriks L, van Duijn CM, Cras P, et al. Presenile dementia and cerebral haemorrhage linked to a mutation at codon 692 of the beta-amyloid precursor protein gene. Nat Genet. 1992;1(3):218-221.PubMedGoogle ScholarCrossref 79. Kamino K, Orr HT, Payami H, et al. Linkage and mutational analysis of familial Alzheimer disease kindreds for the APP gene region. Am J Hum Genet. 1992;51(5):998-1014.PubMedGoogle Scholar 80. Levy E, Carman MD, Fernandez-Madrid IJ, et al. Mutation of the Alzheimer’s disease amyloid gene in hereditary cerebral hemorrhage, Dutch type. Science. 1990;248(4959):1124-1126.PubMedGoogle ScholarCrossref 81. Grabowski TJ, Cho HS, Vonsattel JP, Rebeck GW, Greenberg SM. Novel amyloid precursor protein mutation in an Iowa family with dementia and severe cerebral amyloid angiopathy. Ann Neurol. 2001;49(6):697-705.PubMedGoogle ScholarCrossref 82. Kumar-Singh S, De Jonghe C, Cruts M, et al. Nonfibrillar diffuse amyloid deposition due to a gamma(42)-secretase site mutation points to an essential role for N-truncated A beta(42) in Alzheimer’s disease. Hum Mol Genet. 2000;9(18):2589-2598.PubMedGoogle ScholarCrossref 83. Cruts M, Dermaut B, Rademakers R, Van den Broeck M, Stögbauer F, Van Broeckhoven C. Novel APP mutation V715A associated with presenile Alzheimer’s disease in a German family. J Neurol. 2003;250(11):1374-1375.PubMedGoogle ScholarCrossref 84. Ancolio K, Dumanchin C, Barelli H, et al. Unusual phenotypic alteration of beta amyloid precursor protein (betaAPP) maturation by a new Val-715 –> Met betaAPP-770 mutation responsible for probable early-onset Alzheimer’s disease. Proc Natl Acad Sci U S A. 1999;96(7):4119-4124.PubMedGoogle ScholarCrossref 85. Eckman CB, Mehta ND, Crook R, et al. A new pathogenic mutation in the APP gene (I716V) increases the relative proportion of A beta 42(43). Hum Mol Genet. 1997;6(12):2087-2089.PubMedGoogle ScholarCrossref 86. Guerreiro RJ, Baquero M, Blesa R, et al. Genetic screening of Alzheimer’s disease genes in Iberian and African samples yields novel mutations in presenilins and APP. Neurobiol Aging. 2010;31(5):725-731.PubMedGoogle ScholarCrossref 87. Kwok JB, Li QX, Hallupp M, et al. Novel Leu723Pro amyloid precursor protein mutation increases amyloid beta42(43) peptide levels and induces apoptosis. Ann Neurol. 2000;47(2):249-253.PubMedGoogle ScholarCrossref 88. Theuns J, Marjaux E, Vandenbulcke M, et al. Alzheimer dementia caused by a novel mutation located in the APP C-terminal intracytosolic fragment. Hum Mutat. 2006;27(9):888-896.PubMedGoogle ScholarCrossref 89. Selkoe DJ. Amyloid beta-protein and the genetics of Alzheimer’s disease. J Biol Chem. 1996;271(31):18295-18298.PubMedGoogle ScholarCrossref 90. Hardy J. New insights into the genetics of Alzheimer’s disease. Ann Med. 1996;28(3):255-258.PubMedGoogle ScholarCrossref 91. Bateman RJ, Xiong C, Benzinger TL, et al; Dominantly Inherited Alzheimer Network. Clinical and biomarker changes in dominantly inherited Alzheimer’s disease. N Engl J Med. 2012;367(9):795-804.PubMedGoogle ScholarCrossref 92. Orgogozo JM, Gilman S, Dartigues JF, et al. Subacute meningoencephalitis in a subset of patients with AD after Abeta42 immunization. Neurology. 2003;61(1):46-54.PubMedGoogle ScholarCrossref 93. Fox NC, Black RS, Gilman S, et al; AN1792(QS-21)-201 Study. Effects of Abeta immunization (AN1792) on MRI measures of cerebral volume in Alzheimer disease. Neurology. 2005;64(9):1563-1572.PubMedGoogle ScholarCrossref 94. Salloway S, Sperling R, Gilman S, et al; Bapineuzumab 201 Clinical Trial Investigators. A phase 2 multiple ascending dose trial of bapineuzumab in mild to moderate Alzheimer disease. Neurology. 2009;73(24):2061-2070.PubMedGoogle ScholarCrossref 95. Adolfsson O, Pihlgren M, Toni N, et al. An effector-reduced anti-β-amyloid (Aβ) antibody with unique aβ binding properties promotes neuroprotection and glial engulfment of Aβ. J Neurosci. 2012;32(28):9677-9689.PubMedGoogle ScholarCrossref 96. Bohrmann B, Baumann K, Benz J, et al. Gantenerumab: a novel human anti-Aβ antibody demonstrates sustained cerebral amyloid-β binding and elicits cell-mediated removal of human amyloid-β. J Alzheimers Dis. 2012;28(1):49-69.PubMedGoogle Scholar 97. Farlow M, Arnold SE, van Dyck CH, et al. Safety and biomarker effects of solanezumab in patients with Alzheimer’s disease. Alzheimers Dement. 2012;8(4):261-271.PubMedGoogle ScholarCrossref 98. Relkin NR, Szabo P, Adamiak B, et al. 18-Month study of intravenous immunoglobulin for treatment of mild Alzheimer disease. Neurobiol Aging. 2009;30(11):1728-1736.PubMedGoogle ScholarCrossref 99. Gilman S, Koller M, Black RS, et al; AN1792(QS-21)-201 Study Team. Clinical effects of Abeta immunization (AN1792) in patients with AD in an interrupted trial. Neurology. 2005;64(9):1553-1562.PubMedGoogle ScholarCrossref 100. Blennow K, Zetterberg H, Rinne JO, et al; AAB-001 201/202 Investigators. Effect of immunotherapy with bapineuzumab on cerebrospinal fluid biomarker levels in patients with mild to moderate Alzheimer disease. Arch Neurol. 2012;69(8):1002-1010.PubMedGoogle ScholarCrossref 101. Miller G. Alzheimer’s research: stopping Alzheimer’s before it starts. Science. 2012;337(6096):790-792.PubMedGoogle ScholarCrossref 102. Morris JC, Aisen PS, Bateman RJ, et al. Developing an international network for Alzheimer research: The Dominantly Inherited Alzheimer Network. Clin Investig (Lond). 2012;2(10):975-984.PubMedGoogle ScholarCrossref 103. Reiman EM, Langbaum JB, Fleisher AS, et al. Alzheimer’s Prevention Initiative: a plan to accelerate the evaluation of presymptomatic treatments. J Alzheimers Dis. 2011;26(suppl 3):321-329.PubMedGoogle Scholar 104. Lambracht-Washington D, Rosenberg RN. DNA Aβ42 immunization generates a multivalent vaccine: antibodies in plasma of active full-length DNA Aβ42 immunized mice show polyclonal Aβ42 peptide binding. Paper presented at: Alzheimer's Association International Conference; 2015;Washington, DC. 105. Vasilevko V, Pop V, Kim HJ, et al. Linear and conformation specific antibodies in aged beagles after prolonged vaccination with aggregated Abeta. Neurobiol Dis. 2010;39(3):301-310.PubMedGoogle ScholarCrossref 106. Hatami A, Albay R III, Monjazeb S, Milton S, Glabe C. Monoclonal antibodies against Aβ42 fibrils distinguish multiple aggregation state polymorphisms in vitro and in Alzheimer disease brain. J Biol Chem. 2014;289(46):32131-32143.PubMedGoogle ScholarCrossref 107. Qu BX, Lambracht-Washington D, Fu M, Eagar TN, Stüve O, Rosenberg RN. Analysis of three plasmid systems for use in DNA A beta 42 immunization as therapy for Alzheimer’s disease. Vaccine. 2010;28(32):5280-5287.PubMedGoogle ScholarCrossref 108. Qu B, Boyer PJ, Johnston SA, Hynan LS, Rosenberg RN. Abeta42 gene vaccination reduces brain amyloid plaque burden in transgenic mice. J Neurol Sci. 2006;244(1-2):151-158.PubMedGoogle ScholarCrossref 109. Qu BX, Xiang Q, Li L, Johnston SA, Hynan LS, Rosenberg RN. Abeta42 gene vaccine prevents Abeta42 deposition in brain of double transgenic mice. J Neurol Sci. 2007;260(1-2):204-213.PubMedGoogle ScholarCrossref 110. Lambracht-Washington D, Rosenberg RN. Anti-amyloid beta to tau-based immunization: Developments in immunotherapy for Alzheimer disease. Immunotargets Ther. 2013;2013(2):105-114.PubMedGoogle ScholarCrossref 111. Lambracht-Washington D, Qu BX, Fu M, et al. A peptide prime-DNA boost immunization protocol provides significant benefits as a new generation Aβ42 DNA vaccine for Alzheimer disease. J Neuroimmunol. 2013;254(1-2):63-68.PubMedGoogle ScholarCrossref 112. Lambracht-Washington D, Qu BX, Fu M, et al. DNA immunization against amyloid beta 42 has high potential as safe therapy for Alzheimer’s disease as it diminishes antigen-specific Th1 and Th17 cell proliferation. Cell Mol Neurobiol. 2011;31(6):867-874.PubMedGoogle ScholarCrossref 113. Lambracht-Washington D, Qu BX, Fu M, Eagar TN, Stüve O, Rosenberg RN. DNA beta-amyloid(1-42) trimer immunization for Alzheimer disease in a wild-type mouse model. JAMA. 2009;302(16):1796-1802.PubMedGoogle ScholarCrossref 114. Lambracht-Washington D, Rosenberg RN. Advances in the development of vaccines for Alzheimer’s disease. Discov Med. 2013;15(84):319-326.PubMedGoogle Scholar 115. Lambracht-Washington D, Rosenberg RN. Co-stimulation with TNF receptor superfamily 4/25 antibodies enhances in-vivo expansion of CD4+CD25+Foxp3+ T cells (Tregs) in a mouse study for active DNA Aβ42 immunotherapy. J Neuroimmunol. 2015;278:90-99.PubMedGoogle ScholarCrossref 116. Lambracht-Washington D, Rosenberg RN. A noninflammatory immune response in aged DNA Aβ42-immunized mice supports its safety for possible use as immunotherapy in AD patients. Neurobiol Aging. 2015;36(3):1274-1281.PubMedGoogle ScholarCrossref 117. Rosenberg RN. Defining amyloid pathology in persons with and without dementia syndromes: making the right diagnosis. JAMA. 2015;313(19):1913-1914.PubMedGoogle ScholarCrossref 118. Rosenberg RN, Lambracht-Washington D. DNA Aβ42 vaccination as possible alternative immunotherapy for Alzheimer disease. JAMA Neurol. 2013;70(6):772-773.PubMedGoogle ScholarCrossref 119. Rosenberg RN, Petersen RC. The Human Alzheimer Disease Project: a new call to arms. JAMA Neurol. 2015;72(6):626-628.PubMedGoogle ScholarCrossref http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png JAMA Neurology American Medical Association

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References (138)

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American Medical Association
Copyright
Copyright © 2016 American Medical Association. All Rights Reserved.
ISSN
2168-6149
eISSN
2168-6157
DOI
10.1001/jamaneurol.2016.0301
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Abstract

Abstract Importance To provide a comprehensive review of knowledge of the genomics of Alzheimer disease (AD) and DNA amyloid β 42 (Aβ42) vaccination as a potential therapy. Observations Genotype-phenotype correlations of AD are presented to provide a comprehensive appreciation of the spectrum of disease causation. Alzheimer disease is caused in part by the overproduction and lack of clearance of Aβ protein. Oligomer Aβ, the most toxic species of Aβ, causes direct injury to neurons, accompanied by enhanced neuroinflammation, astrocytosis and gliosis, and eventually neuronal loss. The strongest genetic evidence supporting this hypothesis derives from mutations in the amyloid precursor protein (APP) gene. A detrimental APP mutation at the β-secretase cleavage site linked to early-onset AD found in a Swedish pedigree enhances Aβ production, in contrast to a beneficial mutation 2 residues away in APP that reduces Aβ production and protects against the onset of sporadic AD. A number of common variants associated with late-onset AD have been identified including apolipoprotein E, BIN1, ABC7, PICALM, MS4A4E/MS4A6A, CD2Ap, CD33, EPHA1, CLU, CR1, and SORL1. One or 2 copies of the apolipoprotein E ε4 allele are a major risk factor for late-onset AD. With DNA Aβ42 vaccination, a Th2-type noninflammatory immune response was achieved with a downregulation of Aβ42-specific effector (Th1, Th17, and Th2) cell responses at later immunization times. DNA Aβ42 vaccination upregulated T regulator cells (CD4+, CD25+, and FoxP3+) and its cytokine interleukin 10, resulting in downregulation of T effectors. Conclusions and Relevance Mutations in APP and PS-1 and PS-2 genes that are associated with early-onset, autosomal, dominantly inherited AD, in addition to the at-risk gene polymorphisms responsible for late-onset AD, all indicate a direct and early role of Aβ in the pathogenesis of AD. A translational result of genomic research has been Aβ-reducing therapies including DNA Aβ42 vaccination as a promising approach to delay or prevent this disease. Introduction Alzheimer disease (AD) is characterized by 2 pathological hallmarks, amyloid β (Aβ) protein–containing neuritic plaques and hyperphosphorylated tau-containing paired helical filament in neurofibrillary tangles.1 Amyloid β protein is generated by sequential cleavages of the amyloid precursor protein (APP) by β- and γ-secretases. First, APP is proteolytically processed by β-secretase and generates a 12-kDa C-terminal stub of the APP gene (C99); second, C99 is cleaved by γ-secretase to yield 2 major species of Aβ ending at residue 40 (Aβ40) or residue 42 (Aβ42).2,3 Multiple mutations in the gene encoding APP cause early-onset familial AD, and most of them either lead to an increase in Aβ production or in the ratio of Aβ42 to Aβ40, thus enhancing the aggregation of Aβ peptides. Compared with shorter Aβ peptides, such as Aβ40 and Aβ38, many studies have documented that the 42-residue Aβ42 enhances aggregation propensity,4 leading to accelerated formation of small (low-n) Aβ oligomers.5 Mutations in presenilin genes have similar effect in increasing the ratio of Aβ42 to Aβ40. Cells bearing familial AD mutant genes (APP or PS1/2) produced higher levels of Aβ oligomers,6 which were observed in plasma and postmortem brains of patients with AD.7 Mutation in the tau gene causes frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17).8 In mice, Aβ accumulation can drive tau pathology in vivo.9 Transgenic mice expressing mutant tau show close association between tau mutation, neurofibrillary tangle formation, and neurodegeneration.10,11 Tau protein has been used as a marker for axonal damage, and tau levels in cerebrospinal fluids reflect these changes in the central nervous system. Tau protein levels (total tau, phosphorylated tau, and the ratio) in cerebrospinal fluid have been explored as potential markers for AD. Translational genomic research has developed potential DNA Aβ42 therapeutics for AD. A noninflammatory Th2-mediated immune response with effective levels of anti-Aβ42 antibody has been developed in transgenic AD model mice with the DNA Aβ42 vaccine and is included as a direct extension of advances in AD genomics. Box Section Ref ID Key Points Question What is the current genomic understanding of amyloid β protein–directed therapies for Alzheimer disease? Findings In this review, mutations associated with Alzheimer disease, polymorphisms increasing risk, and amyloid β protein–reducing therapies are defined. The magnitude of defining the genomic and epigenomic factors involved in the pathogenesis of Alzheimer disease and new therapeutic strategies as a result are large in number and complexity. Meaning Effective therapy to delay or prevent Alzheimer disease may be based on a defined genomic understanding. Amyloid Cascade Hypothesis Mechanisms for AD pathogenesis have been extensively explored, and the major hypothesis supported by genetic and neuropathological evidences is the amyloid cascade hypothesis.12 It suggests that AD is caused in part by the overproduction and lack of clearance of Aβ. The most toxic species of Aβ, such as oligomer Aβ, cause direct injury to neurons, accompanied by enhanced neuroinflammation, astrocytosis and gliosis, and eventually neuronal loss. The strongest genetic evidence supporting this hypothesis derives from mutations in the APP gene. A detrimental APP mutation at the β-secretase cleavage site (the APP KM670/671NL mutation), linked to early-onset AD found in a Swedish pedigree, enhances Aβ production,13 in contrast to a beneficial mutation 2 residues away (Icelandic mutation A673T) in APP that reduces Aβ production and protects against the onset of sporadic AD.14 The Swedish mutant APP is a better substrate for recognition and cleavage by the β-secretase, while the Icelandic mutant APP is a much poorer substrate for the β-secretase,14 and the Icelandic mutation greatly attenuates APP–β-secretase interaction.15 The amyloid cascade hypothesis is also supported by additional genetic studies with the other 2 genes associated with early-onset familial AD, the presenilin 1 and 2 genes (PS1 and PS2). To our knowledge, only 3 genes have been identified to associate with familial AD, and all of them encode the key components of the Aβ synthesis pathway. The APP gene encodes the precursor of Aβ and is the substrate of the γ-secretase, and PS1 and PS2 genes encode the proteins that carry the active site of the γ-secretase.16 γ-Secretase is composed of PS1 (or PS2), presenilin enhancer-2, anterior pharynx defective-1, and nicastrin.17-19PS1 itself has proteolytic activity,20,21 which is activated by presenilin enhancer-2.20,22 Nicastrin is the substrate receptor for APP.23 A number of mutations in APP13 or PS1/26,24,25 that link to familial AD affect the γ-secretase cleavage of APP and shift Aβ production from Aβ40 to the more toxic and aggregation-prone Aβ42. Mutations that provide more copies of APP genelike duplications26 and Down syndrome27 generate more Aβ in the brains of those patients. Almost all pathogenic mutations found in the APP gene lead to increased generation of Aβ or the Aβ42 to Aβ40 ratio because Aβ42 is more toxic than Aβ40. The Swedish mutation at the β-secretase cleavage site allows APP to be more accessible to the enzyme and generates more Aβ.13,28 The Arctic mutation of APP (APP E693G) increases the aggregation propensity of Aβ and fibril formation.29 Pathogenic V717F, V717I, and V717L mutations all increase the Aβ42/Aβ40 ratio.30-32 Major AD Risk Genes and Their Involvement in Aβ Metabolism A number of common variants associated with late-onset AD have been identified, including apolipoprotein E (APOE), BIN1, ABCA7, PICALM, MS4A4E/MS4A6A, CD2AP, CD33, EPHA1, CLU, CR1, and SORL1.33-36 One or 2 copies of the APOE ε4 allele is a major risk factor for late-onset AD (LOAD).37,38 The APOE gene has 3 major isoforms, APOE ε2, ε3, and ε4. Brains of patients with sporadic AD carrying the APOE ε4 allele were found to have increased density of Aβ deposits, limited capability to clear Aβ, and enhanced neuroinflammation.39 Binding of APOE loaded with Aβ to cell surface receptors, such as the low-density lipoprotein receptor-related protein-1 (LRP1), is one of the mechanisms for Aβ clearance.40,41 Clusterin (encoded by CLU) directly interacts with soluble Aβ and forms a complex to cross the blood-brain barrier.42 This function is similar to APOE, which acts as a molecular chaperone for Aβ. Both clusterin and APOE directly influence Aβ during its aggregation and deposition. The presence of APOE/clusterin changes Aβ conformation and its toxicity.43,44 Therefore, APOE and clusterin may regulate the conversion of soluble Aβ into insoluble forms such as oligomers, thus suppressing Aβ toxicity and deposition. Because APOE and clusterin are involved in a complex formation with Aβ to cross the blood-brain barrier, both proteins regulate Aβ clearance.45 Alternative pathways for Aβ clearance are mediated by microglia. When extracellular Aβ aggregates, such as Aβ, are engulfed by microglia, inflammasomes (such as NOD-like receptor family pyrin domain-containing 3 [NLRP3]) are triggered, which activate caspases and promote interleukin 1β release.46,47 These aggregates are known to activate innate immune responses via complement pathways, including complement receptor 1 (CR1), which has been associated with LOAD.48 Those Aβ isoforms that bind to scavenger receptors expressed on microglia, such as CD3649 and Scara1,50 enter microglia and activate inflammation. Systems analysis of hundreds of brains with AD reveals changes in networks related to immunologic molecules and microglial cells including microglial protein TYROBP, which binds the microglial receptor TREM2 (triggering receptors expressed on myeloid cells 2) and may regulate CD33 function.51 Genetic mutations found in TREM2 triple a person’s risk for AD52,53 and increased expression of CD33, which functions to suppress Aβ uptake and clearance.54,55 Another transporter protein associated with LOAD is ATP-binding cassette transporter (ABCA7), which belongs to the ATP-binding cassette transporter superfamily that transports many substrates across cell membranes. The ABCA7 gene is involved in the efflux of lipids from cells to lipoprotein particles. In an APP transgenic mouse model (J20) that is deficient in ABCA7, levels of APOE were not changed.56 However, both soluble and insoluble Aβ levels and thioflavine-S–positive plaques were increased in the ABCA7-deficient mice.56,57 In cultured cells, enhanced endocytosis of APP was observed in ABCA7 knockout cells, leading to increased Aβ production.57 Phosphatidylinositol-binding clathrin assembly protein (PICALM) plays a critical role in clathrin-mediated endocytosis and protein/lipid internalization.33 When full-length APP at the cell surface is internalized by clathrin-mediated endocytosis, β- and γ-secretase cleavages occur, and a significant amount of Aβ is generated.58 When endocytosis is promoted by increased synaptic activity, more APP is retrieved from the cell surface to endosomes, resulting in an increase of Aβ generation and secretion.59 Involvement of PICALM with clathrin-mediated endocytosis directly affects APP processing and Aβ synthesis. Bridging integrator 1 (BIN1) is highly expressed in brain, and all BIN1 isoforms interact with clusterin and are involved in surface protein endocytosis. While it is possible that BIN1 influences APP endocytosis and Aβ production, its functional interaction with tau was demonstrated in a drosophila model where knockdown of the BIN1 ortholog Amph could suppress the rough eye phenotype caused by overexpression of human tau.60 Genetic variants in the sortilin-related receptor SORL1 gene are associated with LOAD.61 Reduction of SORL1 expression was observed in vulnerable regions in brains with AD.62,63 In cultured cells, SORL1 interacts with APP and both proteins colocalize in endosomal and Golgi compartments.61,63 They also interact with vacuolar protein sorting-associated protein 35 (VPS35); VPS35 promotes cargo selection in the retromer through SORL1. When expression of SORL1 is increased, SORL1 regulates differential sorting of APP into the retromer recycling pathway, thus reducing Aβ production; when expression of SORL1 is reduced, APP trafficking is directed toward endosome-lysosome compartments that facilitate Aβ production.61 Deficient SORL1 expression in knockout mice resulted in increased levels of Aβ in animal brains.62,63 The PCDH11X gene is a cell surface receptor molecule belonging to the protocadherin gene, which is a subfamily of the cadherin superfamily. Like other cadherins, it mediates cell-cell adhesion and is cleaved by γ-secretase.64 Cadherins, such as E- and N-cadherins, form the complex with PS1/γ-secretase65 and regulate cell-cell interaction after the cleavage by γ-secretase; this process is inhibited by familial AD mutations in PS1.66 Therefore, PCDH11X is believed to play a role in cell signaling that is critical in the development of the central nervous system.67 Genetic variation in PCDH11X is associated with LOAD.68 The MS4A4E/MS4A6A genes belong to the MS4A gene cluster on chromosome 11. The proteins encoded by these similar genes have a common transmembrane domain and likely are cell surface proteins. Their involvement in Aβ production is not known. The EPHA1 gene is a member of the ephrin receptor family. Both ephrins and Eph receptors play important roles in cell and axon guidance, and another member of this family, EphA4, is cleaved by γ-secretase induced by synaptic activity.69 The CD2-associated protein (CD2AP) is a scaffold/adaptor protein and mediates receptor-regulated endocytosis.70 In cultured cells, reducing CD2AP expression results in decreased levels of Aβ and a lower Aβ42/Aβ40 ratio. Knockout of CD2AP in transgenic mice overexpressing PS1 and APP (PS1APP mice) decreased the Aβ42/Aβ40 ratio in the brain; expressing 1 copy of CD2APP in PS1APP mice does not affect Aβ deposition.71 Imbalanced Aβ homeostasis, ie, increased Aβ production and/or decreased Aβ clearance, is an upstream event of neurodegeneration that is directly affected by AD risk gene products (Figure 1). The SORL1, PICALM, and CD2AP genes are involved in endocytic internalization of cell surface APP for β- and γ-secretase cleavages to generate Aβ, while APOE, CLU, TREM2, ABCA7, PICALM, CD33, CD2AP, and CR1 are all involved in Aβ clearance through multiple mechanisms. These risk genes, in addition to familial AD–linked mutant genes APP, PS1, and PS2, all point to the direct and early role of Aβ in the pathogenesis of AD. Amyloid-β–reducing therapies, including DNA Aβ42 vaccination, have a therapeutic potential to delay or prevent the disease (Table). DNA and Peptide Aβ42 Vaccination: Translational Therapy From Genomics The amyloid cascade hypothesis postulates that Aβ deposition in the brain is a primary event necessary in the multifactoral pathogenesis of AD.12,89,90 It has been demonstrated that Aβ deposition precedes AD symptoms by at least 20 years.91 Therapeutic approaches using active and passive immunizations against Aβ have a high possibility to be effective in removing amyloid from the brain and thereby delaying or preventing downstream pathologies. Since 2000, a number of clinical trials for AD immunotherapy have started, have failed, and are continuing.92-99 Amyloid β protein at resiude 42 peptide vaccination with adjuvant in the clinical trial AN179292,93,99 resulted in an autoimmune meningoencephalitis with T cells infiltrating the brain of affected vaccinated patients, and the study was stopped. A clinical trial94,100 with the monoclonal antiamyloid antibody bapineuzumab reduced the level of amyloid accumulation as seen by amyloid imaging but had no clinical benefit in patients expressing clinical signs of AD. New studies started between 2013 and 2015 focus on therapy in patient cohorts before the onset of clinical symptoms of AD.101 These include the Dominantly Inherited Alzheimer Network study,102 the Alzheimer Prevention Initiative, and the Treatment of Asymptomatic Alzheimer.103 A major achievement will occur if passive Aβ immunotherapy for AD can be shown to have clinical benefit. If and when these new prevention studies using passive immunizations with anti-Aβ antibodies provide clinical benefit by delaying or preventing AD, active vaccination, potentially with a DNA Aβ42 vaccine, will increase in interest because it induces an effective and noninflammatory immune response and is applied more efficiently and economically to large populations. A translational result of genomic research has been the development of immunization, with a full-length DNA Aβ42 plasmid in mice generating a polyclonal multivalent vaccine.104 Studies in outbreed animals, such as rabbits and dogs, have shown that the immune response to fibrillar Aβ is diverse and reflects the polymorphic structure of the antigen itself. These studies also lead to the conclusion that single therapeutic monoclonal antibodies with 1 specific epitope may not be able to target all the different aggregates to have an effect on diminishing disease progression.105,106 We have developed an Aβ42 plasmid encoding 3 copies of the full-length Aβ42 sequence. Transcription of Aβ42 is initiated by the transcription factor Gal4, which is encoded by a second plasmid that is delivered simultaneously by cotransfection (Figure 2). This approach had been shown to increase the expression of the Aβ42 sequence without causing Aβ42 cytotoxicity in the transfected cells.107 Immunization with Aβ1-42 is strongly influenced by the fact that this is a self-antigen, and tolerance against self-antigens has to be broken. In wild-type mice, human Aβ42 is a foreign antigen owing to 3 amino acid alterations in the N-terminal segment of the peptide, and wild-type mice produce high levels of anti-Aβ antibodies following immunization. Higher levels of antibody produced in the wild-type mouse are owing to the fact that the DNA in the plasmid coding for Aβ42 peptide is of human type. This explains the differences in the comparison of the antibody responses in wild-type mice and human APP transgenic mice. As in the APP transgenic mouse receiving the DNA Aβ42 plasmid, the expressed Aβ42 peptide in the brain and in the vaccinated skin cells is both of human type. The eFigure in the Supplement shows the analysis of double transgenic and wild-type mice that have been immunized 9 times with the DNA Aβ42 vaccine via gene gun administration. The wild-type mice in this group reached antibody levels with a mean (SD) of 63 (18.16) μg/mL of plasma and the transgenic mice had antibody levels with a mean (SD) of 13.51 (9.18) μg/mL of plasma (P < .001). In AD mouse models, we have demonstrated up to a 50% reduction in brain amyloid following full-length DNA Aβ42 vaccination.108-110 In Figure 3, the results shown were from 2 double transgenic mouse cohorts, from which amyloid levels in the brain had been analyzed 2 weeks following the last immunization (Figure 3A) or 4 months after the last immunization (Figure 3B). Group A showed an amyloid reduction of 65% and group B showed a reduction of Aβ1-42 brain levels of 25%. In both groups, the amyloid reduction was substantial in comparison with the control DNA (Luc)–immunized mice (Mann-Whitney test: P = .006 and P = .007, respectively). The marked difference between these 2 groups is explained by the time differences between final immunizations and brain level analyses (14 days and 4 months following the last immunization; 12 and 16 months of age) and the marked differences in total Aβ42 levels in the brain owing to the 4-month age difference between groups A and B. Concentration of Aβ42 in the brain increased from 10 μg/g wet tissue to 50 μg/g in the Luc control mice owing to increased AD pathology with the age progression in these mice. With DNA Aβ42 vaccination, a Th2-type noninflammatory immune response was achieved, with a downregulation of Aβ42-specific T effector (Th1, Th17, and Th2) cell responses at later immunization times.111-116 On the other hand, DNA Aβ42 vaccination upregulated T regulator cells (CD4+, CD25+, and FoxP3+) and the cytokine interleukin 10, resulting in downregulation of T effectors. In distinction, Aβ42 peptide vaccination induced the opposite effect, with upregulation of T effectors (CD4+, CD25+, and FoxP3-) and no effect on T regulator cells. Thus, the immune response following DNA immunization differs quantitatively and qualitatively from the immune response elicited by Aβ42 peptide immunization. DNA Aβ42 immunization with downregulation of T effectors (Th1, Th17, and Th2 cells) would significantly reduce the opportunity for cytotoxic T cells from migrating and transiting through brain, which was evident in the Aβ42 peptide vaccine clinical trial AN1792, resulting in meningoencephalitis.92,115 Immunizations of 16 New Zealand white rabbits produced after 5 vaccinations anti-Aβ42 antibodies at mean levels of 250 µg/mL of serum. The isotyping of the serum antibody showed IgG, IgM, and IgA anti-Aβ42 antibodies. In autopsies of 9 rabbits, there was no evidence of meningoencephalitis. Immunizations of 6 rhesus monkeys produced after 4 vaccinations of anti-Aβ42 antibodies at mean levels of 112.6 µg/mL of serum and they have remained healthy with no adverse effects (D.L.-W. and R.N.R., preliminary unpublished observations). Conclusions Research into the genetics and genomics of AD has made major strides in the past decade. The PS1, PS2, and APP gene mutations have been documented to result in aggressive, early-onset autosomal dominant disease. Polymorphisms in multiple genes have been shown to increase the risk for the disease. A polymorphism in the APP gene, preventing binding of β-secretase to APP in APOE4 persons and impairing production of Aβ42 peptide being processed from the parent APP molecule, prevents the clinical expression of AD and is in strong support of the amyloid cascade hypothesis. Amyloid imaging has provided the accurate means to identify asymptomatic at-risk persons accumulating amyloid to test antiamyloid therapies.117 Active vaccination with a DNA Aβ42 vaccine offers a potential effective and noninflammatory approach and is one of several active vaccination approaches after demonstration of clinical benefit from passive antiamyloid antibody therapy.118 The magnitude of defining the genomic and epigenomic factors involved in the pathogenesis of AD and new therapeutic strategies that will occur as a result are large in number and complexity. The Human Alzheimer Disease Project, an undertaking at the level of commitment and funding equivalent to the Human Genome Project, is necessary and required to stem the crescendo of anticipated increases in the prevalence of this disease in the foreseeable future.119 Section Editor: David E. Pleasure, MD. Back to top Article Information Corresponding Author: Roger N. Rosenberg, MD, University of Texas Southwestern Medical Center, Department of Neurology and Neurotherapeutics, Dallas, TX 75390 (roger.rosenberg@utsouthwestern.edu). Accepted for Publication: January 22, 2016. Published Online: May 2, 2016. doi:10.1001/jamaneurol.2016.0301. Author Contributions: Dr Rosenberg had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. Each of the authors has provided ideas and concepts and has contributed to the writing of the manuscript. Study concept and design: Rosenberg, Yu, Xia. Acquisition, analysis, or interpretation of data: Labracht-Washington. Drafting of the manuscript: Rosenberg, Xia. Critical revision of the manuscript for important intellectual content: All authors. Obtained funding: Xia. Study supervision: Xia. Conflict of Interest Disclosures: Dr Rosenberg is director of the Alzheimer’s Disease Center at the University of Texas Southwestern Medical Center at Dallas. He received a US patent for “Amyloid β Gene Vaccines” in 2009. Funding/Support: Dr Rosenberg is principal investigator of the National Institutes of Health/National Institute on Aging grant P30AG12300-16. He receives funding from the Rudman Partnership, AWARE Group in Dallas, Freiberger Family Fund, McCune/Losinger Fund, Presbyterian Foundation, North Foundation, the Darryl K Royal Foundation, and the Zale Foundation. Dr Xia received funding from award I21BX002215 from the Biomedical Laboratory Research and Development Service of the Veterans Affairs Office of Research and Development. Role of the Funder/Sponsor: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. Disclaimer: Dr Rosenberg is the Editor of JAMA Neurology but was not involved in the editorial review or the decision to accept the manuscript for publication.The views expressed in this article are those of the authors and do not represent the views of the US Department of Veterans Affairs or the US Government. References 1. Selkoe DJ; American College of Physicians; American Physiological Society. Alzheimer disease: mechanistic understanding predicts novel therapies. Ann Intern Med. 2004;140(8):627-638.PubMedGoogle ScholarCrossref 2. Haass C, Schlossmacher MG, Hung AY, et al. Amyloid beta-peptide is produced by cultured cells during normal metabolism. Nature. 1992;359(6393):322-325.PubMedGoogle ScholarCrossref 3. Shoji M, Golde TE, Ghiso J, et al. Production of the Alzheimer amyloid beta protein by normal proteolytic processing. Science. 1992;258(5079):126-129.PubMedGoogle ScholarCrossref 4. Jarrett JT, Berger EP, Lansbury PT Jr. The carboxy terminus of the beta amyloid protein is critical for the seeding of amyloid formation: implications for the pathogenesis of Alzheimer’s disease. Biochemistry. 1993;32(18):4693-4697.PubMedGoogle ScholarCrossref 5. Walsh DM, Selkoe DJ. Deciphering the molecular basis of memory failure in Alzheimer’s disease. Neuron. 2004;44(1):181-193.PubMedGoogle ScholarCrossref 6. Xia W, Zhang J, Kholodenko D, et al. Enhanced production and oligomerization of the 42-residue amyloid beta-protein by Chinese hamster ovary cells stably expressing mutant presenilins. J Biol Chem. 1997;272(12):7977-7982.PubMedGoogle ScholarCrossref 7. Xia W, Yang T, Shankar G, et al. A specific enzyme-linked immunosorbent assay for measuring beta-amyloid protein oligomers in human plasma and brain tissue of patients with Alzheimer disease. Arch Neurol. 2009;66(2):190-199.PubMedGoogle ScholarCrossref 8. Hutton M. Molecular genetics of chromosome 17 tauopathies. Ann N Y Acad Sci. 2000;920:63-73.PubMedGoogle ScholarCrossref 9. Lee VM, Trojanowski JQ. Progress from Alzheimer’s tangles to pathological tau points towards more effective therapies now. J Alzheimers Dis. 2006;9(3)(suppl):257-262.PubMedGoogle Scholar 10. Lewis J, McGowan E, Rockwood J, et al. Neurofibrillary tangles, amyotrophy, and progressive motor disturbance in mice expressing mutant (P301L) tau protein. Nat Genet. 2000;25(4):402-405.PubMedGoogle ScholarCrossref 11. Götz J, Chen F, van Dorpe J, Nitsch RM. Formation of neurofibrillary tangles in P301l tau transgenic mice induced by Abeta 42 fibrils. Science. 2001;293(5534):1491-1495.PubMedGoogle ScholarCrossref 12. Hardy J, Selkoe DJ. The amyloid hypothesis of Alzheimer’s disease: progress and problems on the road to therapeutics. Science. 2002;297(5580):353-356.PubMedGoogle ScholarCrossref 13. Citron M, Oltersdorf T, Haass C, et al. Mutation of the beta-amyloid precursor protein in familial Alzheimer’s disease increases beta-protein production. Nature. 1992;360(6405):672-674.PubMedGoogle ScholarCrossref 14. Jonsson T, Atwal JK, Steinberg S, et al. A mutation in APP protects against Alzheimer’s disease and age-related cognitive decline. Nature. 2012;488(7409):96-99.PubMedGoogle ScholarCrossref 15. Das U, Wang L, Ganguly A, et al. Visualizing APP and BACE-1 approximation in neurons yields insight into the amyloidogenic pathway. Nat Neurosci. 2016;19(1):55-64.PubMedGoogle ScholarCrossref 16. Wolfe MS, Xia W, Ostaszewski BL, Diehl TS, Kimberly WT, Selkoe DJ. Two transmembrane aspartates in presenilin-1 required for presenilin endoproteolysis and gamma-secretase activity. Nature. 1999;398(6727):513-517.PubMedGoogle ScholarCrossref 17. Sherrington R, Rogaev EI, Liang Y, et al. Cloning of a gene bearing missense mutations in early-onset familial Alzheimer’s disease. Nature. 1995;375(6534):754-760.PubMedGoogle ScholarCrossref 18. Francis R, McGrath G, Zhang J, et al. aph-1 And pen-2 are required for Notch pathway signaling, gamma-secretase cleavage of betaAPP, and presenilin protein accumulation. Dev Cell. 2002;3(1):85-97.PubMedGoogle ScholarCrossref 19. Yu G, Nishimura M, Arawaka S, et al. Nicastrin modulates presenilin-mediated notch/glp-1 signal transduction and betaAPP processing. Nature. 2000;407(6800):48-54.PubMedGoogle ScholarCrossref 20. Ahn K, Shelton CC, Tian Y, et al. Activation and intrinsic gamma-secretase activity of presenilin 1. Proc Natl Acad Sci U S A. 2010;107(50):21435-21440.PubMedGoogle ScholarCrossref 21. Lessard CB, Wagner SL, Koo EH. And four equals one: presenilin takes the gamma-secretase role by itself. Proc Natl Acad Sci U S A. 2010;107(50):21236-21237.PubMedGoogle ScholarCrossref 22. Li YM, Xu M, Lai MT, et al. Photoactivated gamma-secretase inhibitors directed to the active site covalently label presenilin 1. Nature. 2000;405(6787):689-694.PubMedGoogle ScholarCrossref 23. Shah S, Lee SF, Tabuchi K, et al. Nicastrin functions as a gamma-secretase-substrate receptor. Cell. 2005;122(3):435-447.PubMedGoogle ScholarCrossref 24. Citron M, Westaway D, Xia W, et al. Mutant presenilins of Alzheimer’s disease increase production of 42-residue amyloid beta-protein in both transfected cells and transgenic mice. Nat Med. 1997;3(1):67-72.PubMedGoogle ScholarCrossref 25. Scheuner D, Eckman C, Jensen M, et al. Secreted amyloid beta-protein similar to that in the senile plaques of Alzheimer’s disease is increased in vivo by the presenilin 1 and 2 and APP mutations linked to familial Alzheimer’s disease. Nat Med. 1996;2(8):864-870.PubMedGoogle ScholarCrossref 26. Rovelet-Lecrux A, Hannequin D, Raux G, et al. APP locus duplication causes autosomal dominant early-onset Alzheimer disease with cerebral amyloid angiopathy. Nat Genet. 2006;38(1):24-26.PubMedGoogle ScholarCrossref 27. Wisniewski KE, Wisniewski HM, Wen GY. Occurrence of neuropathological changes and dementia of Alzheimer’s disease in Down’s syndrome. Ann Neurol. 1985;17(3):278-282.PubMedGoogle ScholarCrossref 28. Haass C, Lemere CA, Capell A, et al. The Swedish mutation causes early-onset Alzheimer’s disease by beta-secretase cleavage within the secretory pathway. Nat Med. 1995;1(12):1291-1296.PubMedGoogle ScholarCrossref 29. Nilsberth C, Westlind-Danielsson A, Eckman CB, et al. The “Arctic” APP mutation (E693G) causes Alzheimer’s disease by enhanced Abeta protofibril formation. Nat Neurosci. 2001;4(9):887-893.PubMedGoogle ScholarCrossref 30. Goate A, Chartier-Harlin M-C, Mullan M, et al. Segregation of a missense mutation in the amyloid precursor protein gene with familial Alzheimer’s disease. Nature. 1991;349(6311):704-706.PubMedGoogle ScholarCrossref 31. Murrell JR, Hake AM, Quaid KA, Farlow MR, Ghetti B. Early-onset Alzheimer disease caused by a new mutation (V717L) in the amyloid precursor protein gene. Arch Neurol. 2000;57(6):885-887.PubMedGoogle ScholarCrossref 32. Murrell J, Farlow M, Ghetti B, Benson MD. A mutation in the amyloid precursor protein associated with hereditary Alzheimer’s disease. Science. 1991;254(5028):97-99.PubMedGoogle ScholarCrossref 33. Harold D, Abraham R, Hollingworth P, et al. Genome-wide association study identifies variants at CLU and PICALM associated with Alzheimer’s disease [published correction appears in Nat Genet. 2013;45(6):712]. Nat Genet. 2009;41(10):1088-1093.PubMedGoogle ScholarCrossref 34. Naj AC, Jun G, Beecham GW, et al. Common variants at MS4A4/MS4A6E, CD2AP, CD33 and EPHA1 are associated with late-onset Alzheimer’s disease. Nat Genet. 2011;43(5):436-441.PubMedGoogle ScholarCrossref 35. Hollingworth P, Harold D, Sims R, et al; Alzheimer’s Disease Neuroimaging Initiative; CHARGE consortium; EADI1 consortium. Common variants at ABCA7, MS4A6A/MS4A4E, EPHA1, CD33, and CD2AP are associated with Alzheimer’s disease. Nat Genet. 2011;43(5):429-435.PubMedGoogle ScholarCrossref 36. Lambert JC, Heath S, Even G, et al; European Alzheimer’s Disease Initiative Investigators. Genome-wide association study identifies variants at CLU and CR1 associated with Alzheimer’s disease. Nat Genet. 2009;41(10):1094-1099.PubMedGoogle ScholarCrossref 37. Strittmatter WJ, Saunders AM, Schmechel D, et al. Apolipoprotein E: high-avidity binding to beta-amyloid and increased frequency of type 4 allele in late-onset familial Alzheimer disease. Proc Natl Acad Sci U S A. 1993;90(5):1977-1981.PubMedGoogle ScholarCrossref 38. Rebeck GW, Reiter JS, Strickland DK, Hyman BT. Apolipoprotein E in sporadic Alzheimer’s disease: allelic variation and receptor interactions. Neuron. 1993;11(4):575-580.PubMedGoogle ScholarCrossref 39. Castellano JM, Kim J, Stewart FR, et al. Human apoE isoforms differentially regulate brain amyloid-β peptide clearance. Sci Transl Med. 2011;3(89):89ra57.PubMedGoogle ScholarCrossref 40. Sagare A, Deane R, Bell RD, et al. Clearance of amyloid-beta by circulating lipoprotein receptors. Nat Med. 2007;13(9):1029-1031.PubMedGoogle ScholarCrossref 41. Deane R, Wu Z, Sagare A, et al. LRP/amyloid beta-peptide interaction mediates differential brain efflux of Abeta isoforms. Neuron. 2004;43(3):333-344.PubMedGoogle ScholarCrossref 42. Zlokovic BV, Martel CL, Matsubara E, et al. Glycoprotein 330/megalin: probable role in receptor-mediated transport of apolipoprotein J alone and in a complex with Alzheimer disease amyloid beta at the blood-brain and blood-cerebrospinal fluid barriers. Proc Natl Acad Sci U S A. 1996;93(9):4229-4234.PubMedGoogle ScholarCrossref 43. Ma J, Yee A, Brewer HB Jr, Das S, Potter H. Amyloid-associated proteins alpha 1-antichymotrypsin and apolipoprotein E promote assembly of Alzheimer beta-protein into filaments. Nature. 1994;372(6501):92-94.PubMedGoogle ScholarCrossref 44. DeMattos RB, O’dell MA, Parsadanian M, et al. Clusterin promotes amyloid plaque formation and is critical for neuritic toxicity in a mouse model of Alzheimer’s disease. Proc Natl Acad Sci U S A. 2002;99(16):10843-10848.PubMedGoogle ScholarCrossref 45. Bell RD, Sagare AP, Friedman AE, et al. Transport pathways for clearance of human Alzheimer’s amyloid beta-peptide and apolipoproteins E and J in the mouse central nervous system. J Cereb Blood Flow Metab. 2007;27(5):909-918.PubMedGoogle Scholar 46. Halle A, Hornung V, Petzold GC, et al. The NALP3 inflammasome is involved in the innate immune response to amyloid-beta. Nat Immunol. 2008;9(8):857-865.PubMedGoogle ScholarCrossref 47. Heneka MT, Kummer MP, Stutz A, et al. NLRP3 is activated in Alzheimer’s disease and contributes to pathology in APP/PS1 mice. Nature. 2013;493(7434):674-678.PubMedGoogle ScholarCrossref 48. Jun G, Naj AC, Beecham GW, et al; Alzheimer’s Disease Genetics Consortium. Meta-analysis confirms CR1, CLU, and PICALM as alzheimer disease risk loci and reveals interactions with APOE genotypes. Arch Neurol. 2010;67(12):1473-1484.PubMedGoogle ScholarCrossref 49. Sheedy FJ, Grebe A, Rayner KJ, et al. CD36 coordinates NLRP3 inflammasome activation by facilitating intracellular nucleation of soluble ligands into particulate ligands in sterile inflammation. Nat Immunol. 2013;14(8):812-820.PubMedGoogle ScholarCrossref 50. Frenkel D, Wilkinson K, Zhao L, et al. Scara1 deficiency impairs clearance of soluble amyloid-β by mononuclear phagocytes and accelerates Alzheimer’s-like disease progression. Nat Commun. 2013;4(2030):2030.PubMedGoogle Scholar 51. Zhang B, Gaiteri C, Bodea LG, et al. Integrated systems approach identifies genetic nodes and networks in late-onset Alzheimer’s disease. Cell. 2013;153(3):707-720.PubMedGoogle ScholarCrossref 52. Guerreiro R, Wojtas A, Bras J, et al; Alzheimer Genetic Analysis Group. TREM2 variants in Alzheimer’s disease. N Engl J Med. 2013;368(2):117-127.PubMedGoogle ScholarCrossref 53. Jonsson T, Stefansson H, Steinberg S, et al. Variant of TREM2 associated with the risk of Alzheimer’s disease. N Engl J Med. 2013;368(2):107-116.PubMedGoogle ScholarCrossref 54. Griciuc A, Serrano-Pozo A, Parrado AR, et al. Alzheimer’s disease risk gene CD33 inhibits microglial uptake of amyloid beta. Neuron. 2013;78(4):631-643.PubMedGoogle ScholarCrossref 55. Bradshaw EM, Chibnik LB, Keenan BT, et al; Alzheimer Disease Neuroimaging Initiative. CD33 Alzheimer’s disease locus: altered monocyte function and amyloid biology. Nat Neurosci. 2013;16(7):848-850.PubMedGoogle Scholar 56. Kim WS, Li H, Ruberu K, et al. Deletion of Abca7 increases cerebral amyloid-β accumulation in the J20 mouse model of Alzheimer’s disease. J Neurosci. 2013;33(10):4387-4394.PubMedGoogle ScholarCrossref 57. Satoh K, Abe-Dohmae S, Yokoyama S, St George-Hyslop P, Fraser PE. ATP-binding cassette transporter A7 (ABCA7) loss of function alters Alzheimer amyloid processing. J Biol Chem. 2015;290(40):24152-24165.PubMedGoogle ScholarCrossref 58. Perez RG, Squazzo SL, Koo EH. Enhanced release of amyloid beta-protein from codon 670/671 “Swedish” mutant beta-amyloid precursor protein occurs in both secretory and endocytic pathways. J Biol Chem. 1996;271(15):9100-9107.PubMedGoogle ScholarCrossref 59. Cirrito JR, Kang JE, Lee J, et al. Endocytosis is required for synaptic activity-dependent release of amyloid-beta in vivo. Neuron. 2008;58(1):42-51.PubMedGoogle ScholarCrossref 60. Chapuis J, Hansmannel F, Gistelinck M, et al; GERAD consortium. Increased expression of BIN1 mediates Alzheimer genetic risk by modulating tau pathology. Mol Psychiatry. 2013;18(11):1225-1234.PubMedGoogle ScholarCrossref 61. Rogaeva E, Meng Y, Lee JH, et al. The neuronal sortilin-related receptor SORL1 is genetically associated with Alzheimer disease. Nat Genet. 2007;39(2):168-177.PubMedGoogle ScholarCrossref 62. Offe K, Dodson SE, Shoemaker JT, et al. The lipoprotein receptor LR11 regulates amyloid beta production and amyloid precursor protein traffic in endosomal compartments. J Neurosci. 2006;26(5):1596-1603.PubMedGoogle ScholarCrossref 63. Andersen OM, Reiche J, Schmidt V, et al. Neuronal sorting protein-related receptor sorLA/LR11 regulates processing of the amyloid precursor protein. Proc Natl Acad Sci U S A. 2005;102(38):13461-13466.PubMedGoogle ScholarCrossref 64. Haas IG, Frank M, Véron N, Kemler R. Presenilin-dependent processing and nuclear function of gamma-protocadherins. J Biol Chem. 2005;280(10):9313-9319.PubMedGoogle ScholarCrossref 65. Georgakopoulos A, Marambaud P, Efthimiopoulos S, et al. Presenilin-1 forms complexes with the cadherin/catenin cell-cell adhesion system and is recruited to intercellular and synaptic contacts. Mol Cell. 1999;4(6):893-902.PubMedGoogle ScholarCrossref 66. Marambaud P, Wen PH, Dutt A, et al. A CBP binding transcriptional repressor produced by the PS1/epsilon-cleavage of N-cadherin is inhibited by PS1 FAD mutations. Cell. 2003;114(5):635-645.PubMedGoogle ScholarCrossref 67. Blanco P, Sargent CA, Boucher CA, Mitchell M, Affara NA. Conservation of PCDHX in mammals; expression of human X/Y genes predominantly in brain. Mamm Genome. 2000;11(10):906-914.PubMedGoogle ScholarCrossref 68. Carrasquillo MM, Zou F, Pankratz VS, et al. Genetic variation in PCDH11X is associated with susceptibility to late-onset Alzheimer’s disease. Nat Genet. 2009;41(2):192-198.PubMedGoogle ScholarCrossref 69. Inoue E, Deguchi-Tawarada M, Togawa A, et al. Synaptic activity prompts gamma-secretase-mediated cleavage of EphA4 and dendritic spine formation. J Cell Biol. 2009;185(3):551-564.PubMedGoogle ScholarCrossref 70. Lynch DK, Winata SC, Lyons RJ, et al. A Cortactin-CD2-associated protein (CD2AP) complex provides a novel link between epidermal growth factor receptor endocytosis and the actin cytoskeleton. J Biol Chem. 2003;278(24):21805-21813.PubMedGoogle ScholarCrossref 71. Liao F, Jiang H, Srivatsan S, et al. Effects of CD2-associated protein deficiency on amyloid-β in neuroblastoma cells and in an APP transgenic mouse model. Mol Neurodegener. 2015;10:12.PubMedGoogle ScholarCrossref 72. Mullan M, Crawford F, Axelman K, et al. A pathogenic mutation for probable Alzheimer’s disease in the APP gene at the N-terminus of beta-amyloid. Nat Genet. 1992;1(5):345-347.PubMedGoogle ScholarCrossref 73. Citron M, Oltersdorf T, Haass C, et al. Mutation of the beta-amyloid precursor protein in familial Alzheimer’s disease increases beta-protein production. Nature. 1992;360(6405):672-674.PubMedGoogle ScholarCrossref 74. Chen WT, Hong CJ, Lin YT, et al. Amyloid-beta (Aβ) D7H mutation increases oligomeric Aβ42 and alters properties of Aβ-zinc/copper assemblies. PLoS One. 2012;7(4):e35807.PubMedGoogle ScholarCrossref 75. Wakutani Y, Watanabe K, Adachi Y, et al. Novel amyloid precursor protein gene missense mutation (D678N) in probable familial Alzheimer’s disease. J Neurol Neurosurg Psychiatry. 2004;75(7):1039-1042.PubMedGoogle ScholarCrossref 76. Zhou L, Brouwers N, Benilova I, et al. Amyloid precursor protein mutation E682K at the alternative β-secretase cleavage β′-site increases Aβ generation. EMBO Mol Med. 2011;3(5):291-302.PubMedGoogle ScholarCrossref 77. Kaden D, Harmeier A, Weise C, et al. Novel APP/Aβ mutation K16N produces highly toxic heteromeric Aβ oligomers. EMBO Mol Med. 2012;4(7):647-659.PubMedGoogle ScholarCrossref 78. Hendriks L, van Duijn CM, Cras P, et al. Presenile dementia and cerebral haemorrhage linked to a mutation at codon 692 of the beta-amyloid precursor protein gene. Nat Genet. 1992;1(3):218-221.PubMedGoogle ScholarCrossref 79. Kamino K, Orr HT, Payami H, et al. Linkage and mutational analysis of familial Alzheimer disease kindreds for the APP gene region. Am J Hum Genet. 1992;51(5):998-1014.PubMedGoogle Scholar 80. Levy E, Carman MD, Fernandez-Madrid IJ, et al. Mutation of the Alzheimer’s disease amyloid gene in hereditary cerebral hemorrhage, Dutch type. Science. 1990;248(4959):1124-1126.PubMedGoogle ScholarCrossref 81. Grabowski TJ, Cho HS, Vonsattel JP, Rebeck GW, Greenberg SM. Novel amyloid precursor protein mutation in an Iowa family with dementia and severe cerebral amyloid angiopathy. Ann Neurol. 2001;49(6):697-705.PubMedGoogle ScholarCrossref 82. Kumar-Singh S, De Jonghe C, Cruts M, et al. Nonfibrillar diffuse amyloid deposition due to a gamma(42)-secretase site mutation points to an essential role for N-truncated A beta(42) in Alzheimer’s disease. Hum Mol Genet. 2000;9(18):2589-2598.PubMedGoogle ScholarCrossref 83. Cruts M, Dermaut B, Rademakers R, Van den Broeck M, Stögbauer F, Van Broeckhoven C. Novel APP mutation V715A associated with presenile Alzheimer’s disease in a German family. J Neurol. 2003;250(11):1374-1375.PubMedGoogle ScholarCrossref 84. Ancolio K, Dumanchin C, Barelli H, et al. Unusual phenotypic alteration of beta amyloid precursor protein (betaAPP) maturation by a new Val-715 –> Met betaAPP-770 mutation responsible for probable early-onset Alzheimer’s disease. Proc Natl Acad Sci U S A. 1999;96(7):4119-4124.PubMedGoogle ScholarCrossref 85. Eckman CB, Mehta ND, Crook R, et al. A new pathogenic mutation in the APP gene (I716V) increases the relative proportion of A beta 42(43). Hum Mol Genet. 1997;6(12):2087-2089.PubMedGoogle ScholarCrossref 86. Guerreiro RJ, Baquero M, Blesa R, et al. Genetic screening of Alzheimer’s disease genes in Iberian and African samples yields novel mutations in presenilins and APP. Neurobiol Aging. 2010;31(5):725-731.PubMedGoogle ScholarCrossref 87. Kwok JB, Li QX, Hallupp M, et al. Novel Leu723Pro amyloid precursor protein mutation increases amyloid beta42(43) peptide levels and induces apoptosis. Ann Neurol. 2000;47(2):249-253.PubMedGoogle ScholarCrossref 88. Theuns J, Marjaux E, Vandenbulcke M, et al. Alzheimer dementia caused by a novel mutation located in the APP C-terminal intracytosolic fragment. Hum Mutat. 2006;27(9):888-896.PubMedGoogle ScholarCrossref 89. Selkoe DJ. Amyloid beta-protein and the genetics of Alzheimer’s disease. J Biol Chem. 1996;271(31):18295-18298.PubMedGoogle ScholarCrossref 90. Hardy J. New insights into the genetics of Alzheimer’s disease. Ann Med. 1996;28(3):255-258.PubMedGoogle ScholarCrossref 91. Bateman RJ, Xiong C, Benzinger TL, et al; Dominantly Inherited Alzheimer Network. Clinical and biomarker changes in dominantly inherited Alzheimer’s disease. N Engl J Med. 2012;367(9):795-804.PubMedGoogle ScholarCrossref 92. Orgogozo JM, Gilman S, Dartigues JF, et al. Subacute meningoencephalitis in a subset of patients with AD after Abeta42 immunization. Neurology. 2003;61(1):46-54.PubMedGoogle ScholarCrossref 93. Fox NC, Black RS, Gilman S, et al; AN1792(QS-21)-201 Study. Effects of Abeta immunization (AN1792) on MRI measures of cerebral volume in Alzheimer disease. Neurology. 2005;64(9):1563-1572.PubMedGoogle ScholarCrossref 94. Salloway S, Sperling R, Gilman S, et al; Bapineuzumab 201 Clinical Trial Investigators. A phase 2 multiple ascending dose trial of bapineuzumab in mild to moderate Alzheimer disease. Neurology. 2009;73(24):2061-2070.PubMedGoogle ScholarCrossref 95. Adolfsson O, Pihlgren M, Toni N, et al. An effector-reduced anti-β-amyloid (Aβ) antibody with unique aβ binding properties promotes neuroprotection and glial engulfment of Aβ. J Neurosci. 2012;32(28):9677-9689.PubMedGoogle ScholarCrossref 96. Bohrmann B, Baumann K, Benz J, et al. Gantenerumab: a novel human anti-Aβ antibody demonstrates sustained cerebral amyloid-β binding and elicits cell-mediated removal of human amyloid-β. J Alzheimers Dis. 2012;28(1):49-69.PubMedGoogle Scholar 97. Farlow M, Arnold SE, van Dyck CH, et al. Safety and biomarker effects of solanezumab in patients with Alzheimer’s disease. Alzheimers Dement. 2012;8(4):261-271.PubMedGoogle ScholarCrossref 98. Relkin NR, Szabo P, Adamiak B, et al. 18-Month study of intravenous immunoglobulin for treatment of mild Alzheimer disease. Neurobiol Aging. 2009;30(11):1728-1736.PubMedGoogle ScholarCrossref 99. Gilman S, Koller M, Black RS, et al; AN1792(QS-21)-201 Study Team. Clinical effects of Abeta immunization (AN1792) in patients with AD in an interrupted trial. Neurology. 2005;64(9):1553-1562.PubMedGoogle ScholarCrossref 100. Blennow K, Zetterberg H, Rinne JO, et al; AAB-001 201/202 Investigators. Effect of immunotherapy with bapineuzumab on cerebrospinal fluid biomarker levels in patients with mild to moderate Alzheimer disease. Arch Neurol. 2012;69(8):1002-1010.PubMedGoogle ScholarCrossref 101. Miller G. Alzheimer’s research: stopping Alzheimer’s before it starts. Science. 2012;337(6096):790-792.PubMedGoogle ScholarCrossref 102. Morris JC, Aisen PS, Bateman RJ, et al. Developing an international network for Alzheimer research: The Dominantly Inherited Alzheimer Network. Clin Investig (Lond). 2012;2(10):975-984.PubMedGoogle ScholarCrossref 103. Reiman EM, Langbaum JB, Fleisher AS, et al. Alzheimer’s Prevention Initiative: a plan to accelerate the evaluation of presymptomatic treatments. J Alzheimers Dis. 2011;26(suppl 3):321-329.PubMedGoogle Scholar 104. Lambracht-Washington D, Rosenberg RN. DNA Aβ42 immunization generates a multivalent vaccine: antibodies in plasma of active full-length DNA Aβ42 immunized mice show polyclonal Aβ42 peptide binding. Paper presented at: Alzheimer's Association International Conference; 2015;Washington, DC. 105. Vasilevko V, Pop V, Kim HJ, et al. Linear and conformation specific antibodies in aged beagles after prolonged vaccination with aggregated Abeta. Neurobiol Dis. 2010;39(3):301-310.PubMedGoogle ScholarCrossref 106. Hatami A, Albay R III, Monjazeb S, Milton S, Glabe C. Monoclonal antibodies against Aβ42 fibrils distinguish multiple aggregation state polymorphisms in vitro and in Alzheimer disease brain. J Biol Chem. 2014;289(46):32131-32143.PubMedGoogle ScholarCrossref 107. Qu BX, Lambracht-Washington D, Fu M, Eagar TN, Stüve O, Rosenberg RN. Analysis of three plasmid systems for use in DNA A beta 42 immunization as therapy for Alzheimer’s disease. Vaccine. 2010;28(32):5280-5287.PubMedGoogle ScholarCrossref 108. Qu B, Boyer PJ, Johnston SA, Hynan LS, Rosenberg RN. Abeta42 gene vaccination reduces brain amyloid plaque burden in transgenic mice. J Neurol Sci. 2006;244(1-2):151-158.PubMedGoogle ScholarCrossref 109. Qu BX, Xiang Q, Li L, Johnston SA, Hynan LS, Rosenberg RN. Abeta42 gene vaccine prevents Abeta42 deposition in brain of double transgenic mice. J Neurol Sci. 2007;260(1-2):204-213.PubMedGoogle ScholarCrossref 110. Lambracht-Washington D, Rosenberg RN. Anti-amyloid beta to tau-based immunization: Developments in immunotherapy for Alzheimer disease. Immunotargets Ther. 2013;2013(2):105-114.PubMedGoogle ScholarCrossref 111. Lambracht-Washington D, Qu BX, Fu M, et al. A peptide prime-DNA boost immunization protocol provides significant benefits as a new generation Aβ42 DNA vaccine for Alzheimer disease. J Neuroimmunol. 2013;254(1-2):63-68.PubMedGoogle ScholarCrossref 112. Lambracht-Washington D, Qu BX, Fu M, et al. DNA immunization against amyloid beta 42 has high potential as safe therapy for Alzheimer’s disease as it diminishes antigen-specific Th1 and Th17 cell proliferation. Cell Mol Neurobiol. 2011;31(6):867-874.PubMedGoogle ScholarCrossref 113. Lambracht-Washington D, Qu BX, Fu M, Eagar TN, Stüve O, Rosenberg RN. DNA beta-amyloid(1-42) trimer immunization for Alzheimer disease in a wild-type mouse model. JAMA. 2009;302(16):1796-1802.PubMedGoogle ScholarCrossref 114. Lambracht-Washington D, Rosenberg RN. Advances in the development of vaccines for Alzheimer’s disease. Discov Med. 2013;15(84):319-326.PubMedGoogle Scholar 115. Lambracht-Washington D, Rosenberg RN. Co-stimulation with TNF receptor superfamily 4/25 antibodies enhances in-vivo expansion of CD4+CD25+Foxp3+ T cells (Tregs) in a mouse study for active DNA Aβ42 immunotherapy. J Neuroimmunol. 2015;278:90-99.PubMedGoogle ScholarCrossref 116. Lambracht-Washington D, Rosenberg RN. A noninflammatory immune response in aged DNA Aβ42-immunized mice supports its safety for possible use as immunotherapy in AD patients. Neurobiol Aging. 2015;36(3):1274-1281.PubMedGoogle ScholarCrossref 117. Rosenberg RN. Defining amyloid pathology in persons with and without dementia syndromes: making the right diagnosis. JAMA. 2015;313(19):1913-1914.PubMedGoogle ScholarCrossref 118. Rosenberg RN, Lambracht-Washington D. DNA Aβ42 vaccination as possible alternative immunotherapy for Alzheimer disease. JAMA Neurol. 2013;70(6):772-773.PubMedGoogle ScholarCrossref 119. Rosenberg RN, Petersen RC. The Human Alzheimer Disease Project: a new call to arms. JAMA Neurol. 2015;72(6):626-628.PubMedGoogle ScholarCrossref

Journal

JAMA NeurologyAmerican Medical Association

Published: Jul 1, 2016

Keywords: amyloid,alzheimer's disease,mutation,amyloid beta-protein,dna,genomics,brain metabolism,psen1 gene,psen2 gene,neurogenetics,autosomal dominant inheritance,presenilin,genes,vaccination,polymorphism,cd33 antigen,immunization,apolipoprotein e,amyloid beta-protein precursor,immune response

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