Cell Death & Differentiation

Xu, Tong-peng; Ma, Pei; Wang, Wen-yu; Shuai, You; Wang, Yan-fen; Yu, Tao; Xia, Rui; Shu, Yong-qian

doi: 10.1038/s41418-018-0236-ypmid: 30770877

It was found in this study that long intergenic non-protein coding RNA 346 (LINC00346) was an lncRNA aberrantly expressed in gastric cancer (GC) based on multiple Gene Expression Omnibus (GEO) databases of GC cohorts. The LINC00346 gene was recurrently amplified and upregulated in GC, and its expression was positively correlated with poor pathologic stage, large tumor size, and poor prognosis. In addition, the oncogenic transcription factors KLF5 and MYC could bind to the LINC00346 promoter and enhance its expression. Gene Set Enrichment Analysis (GSEA) in the GEO datasets revealed that cell cycle and focal adhesion genes were enriched in patients with high LINC00346 expression. In vitro and in vivo assays of LINC00346 alterations revealed a complex integrated phenotype affecting cell growth, migration and invasion. Strikingly, high-throughput sequencing analysis after LINC00346 alterations highlighted alterations in cell cycle and focal adhesion pathways in GC cells. Mechanistically, argonaute 2 (Ago2) was recruited by LINC00346, which functioned as a molecular sponge for miR-34a-5p by antagonizing its ability to repress CD44, NOTCH1, and AXL protein translation. Taken together, our findings support a model in which the KLF5, MYC/LINC00346/miR-34a-5p cross-talk served as critical effectors in GC tumorigenesis and progression, suggesting a new therapeutic direction in the treatment of GC.

Meng, Chenling; Liao, Jinyue; Zhao, Danfeng; Huang, Huihui; Qin, Jinzhong; Lee, Tin-Lap; Chen, Degui; Chan, Wai-Yee; Xia, Yin

doi: 10.1038/s41418-019-0283-zpmid: 30760872

Lethal (3) malignant brain tumor like 2 (L3MBTL2) is a member of the MBT-domain proteins, which are involved in transcriptional repression and implicated in chromatin compaction. Our previous study has shown that L3MBTL2 is highly expressed in the testis, but its role in spermatogenesis remains unclear. In the present study, we found that L3MBTL2 was most highly expressed in pachytene spermatocytes within the testis. Germ cell-specific ablation of L3mbtl2 in the testis led to increased abnormal spermatozoa, progressive decrease of sperm counts and premature testicular failure in mice. RNA-sequencing analysis on L3mbtl2 deficient testes confirmed that L3MBTL2 was a transcriptional repressor but failed to reveal any significant changes in spermatogenesis-associated genes. Interestingly, L3mbtl2 deficiency resulted in increased γH2AX deposition in the leptotene spermatocytes, subsequent inappropriate retention of γH2AX on autosomes, and defective crossing-over and synapsis during the pachytene stage of meiosis I, and more germ cell apoptosis and degeneration in aging mice. L3MBTL2 interacted with the histone ubiquitin ligase RNF8. Inhibition of L3MBTL2 reduced nuclear RNF8 and ubH2A levels in GC2 cells. L3mbtl2 deficiency led to decreases in the levels of the RNF8 and ubH2A pathway and in histone acetylation in elongating spermatids, and in protamine 1 deposition and chromatin condensation in sperm. These results suggest that L3MBTL2 plays important roles in chromatin remodeling during meiosis and spermiogenesis.

del Blanco, Beatriz; Guiretti, Deisy; Tomasoni, Romana; Lopez-Cascales, María; Muñoz-Viana, Rafael; Lipinski, Michal; Scandaglia, Marilyn; Coca, Yaiza; Olivares, Román; Valor, Luis; Herrera, Eloísa; Barco, Angel

doi: 10.1038/s41418-019-0285-xpmid: 30850733

The CREB-binding protein (CBP) exerts tight control of developmental processes. Here, we investigated the consequences of its selective ablation in newborn neurons. Mice in which CBP was eliminated during neuronal differentiation showed perinatal death and defective diaphragm innervation. Adult-born neurons also showed impaired growth and maturation after inducible and restricted CBP loss in dentate gyrus neuroprogenitors. Consistent with these in vivo findings, cultured neurons displayed impaired outgrowth, immature spines, and deficient activity-dependent synaptic remodeling after CBP ablation. These deficits coincided with broad transcriptional changes affecting genes involved in neuronal growth and plasticity. The affected gene set included many predicted targets of both CBP and the serum response factor (SRF), an activity-regulated transcription factor involved in structural plasticity. Notably, increasing SRF activity in a CBP-independent manner ameliorated the transcriptional, synaptic, and growth defects. These results underscore the relevance of CBP–SRF interactions during neuronal outgrowth and synaptic maturation, and demonstrate that CBP plays an essential role in supporting the gene program underlying the last steps of neuronal differentiation, both during development and in the adult brain.

Siddiqui, Aarif; Gollavilli, Paradesi; Schwab, Annemarie; Vazakidou, Maria; Ersan, Pelin; Ramakrishnan, Mallika; Pluim, Dick; Coggins, Si’Ana; Saatci, Ozge; Annaratone, Laura; Schellens, Jan; Kim, Baek; Asangani, Irfan; Rasheed, Suhail; Marchiò, Caterina; Sahin, Ozgur; Ceppi, Paolo

Shao, Jialiang; Lu, Jiongjiong; Zhu, Wencheng; Yu, Hua; Jing, Xiaoqian; Wang, Yi-Lin; Wang, Xiang; Wang, Xiong-Jun

doi: 10.1038/s41418-019-0293-xpmid: 30728460

TP53 is the most frequently mutated gene in human cancer, whereas tumors with wild-type TP53 develop alternative strategies to survive. Identifying new regulators of p53 reactivation would greatly contribute to the development of cancer therapies. After screening the entire genome in liver cancer cells, we identified lysyl oxidase-like 4 (LOXL4) as a novel regulator for p53 activation. We found that 5-azacytidine (5-aza-CR) induces LOXL4 upregulation, with LOXL4 subsequently binding the basic domain of p53 via its low-isoelectric point region. The interaction between LOXL4 and p53 induces the reactivation of compromised p53, resulting in cell death. Furthermore, the nude mouse xenograft model showed that the 5-aza-CR-dependent LOXL4-p53 axis reduces tumor growth. A positive correlation between LOXL4 expression and overall survival in liver cancer patients with wild-type p53 tumors was observed. In conclusion, we found that 5-aza-CR-induced LOXL4 upregulation reactivates wild-type p53 and triggers cell death, which blocks liver cancer development.

Zhang, Xiaojin; Chen, Xuan; qi, Tao; Kong, Qiuyue; Cheng, Hao; Cao, Xiaofei; Li, Yuehua; Li, Chuanfu; Liu, Li; Ding, Zhengnian

doi: 10.1038/s41418-019-0300-2pmid: 30742088

Obesity is one of the most serious public health problems. Peroxisome proliferator-activated receptor γ (PPARγ) plays the master role in adipocyte differentiation for obesity development. However, optimum anti-obesity drug has yet been developed, mandating more investigation to identify novel regulator in obesity pathogenesis. Heat shock protein 12A (HSPA12A) encodes a novel member of the HSP70 family. Here, we report that obese patients showed increased adipose HSPA12A expression, which was positively correlated with increase of body mass index. Intriguingly, knockout of HSPA12A (Hspa12a −/− ) in mice attenuated high-fat diet (HFD)-induced weight gain, adiposity, hyperlipidemia, and hyperglycemia compared to their wild type (WT) littermates. Increased insulin sensitivity was observed in Hspa12a −/− mice compared to WT mice. The HFD-induced upregulation of PPARγ and its target adipogenic genes in white adipose tissues (WAT) of Hspa12a −/− mice were also attenuated. Loss- and gain-of-function studies revealed that the differentiation of primary adipocyte precursors, as well as the expression of PPARγ and target adipogenic genes during the differentiation, was suppressed by HSPA12A deficiency whereas promoted by HSPA12A overexpression. Importantly, PPARγ inhibition by GW9662 reversed the HSPA12A-mediated adipocyte differentiation. On the other hand, HSPA12A expression was downregulated by PPARγ inhibition but upregulated by PPARγ activation in primary adipocytes. A direct binding of PPARγ to the PPAR response element in the Hspa12a promoter region was confirmed by chromatin immunoprecipitation assay, and this binding was increased after differentiation of primary adipocytes. These findings indicate that HSPA12A is a novel regulator of adipocyte differentiation and diet-induced obesity through a positive feedback regulation with PPARγ. HSPA12A inhibition might represent a viable strategy for the management of obesity in humans.

Li, Lei; Zheng, Yin-Li; Jiang, Chen; Fang, Shuo; Zeng, Ting-Ting; Zhu, Ying-Hui; Li, Yan; Xie, Dan; Guan, Xin-Yuan

doi: 10.1038/s41418-019-0301-1pmid: 30778199

Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies and lacks targeted therapies. Here, we reported a novel potential therapeutic target hematological and neurological expressed 1 like (HN1L) in HCC. First, HCC tissue microarray analysis showed that HN1L was frequently up-regulated in cancer tissues than that in normal liver tissues, which significantly associated with tumor size, local invasion, distant metastases, and poor prognosis for HCC patients. Functional studies demonstrated that ectopic expression of HN1L could increase cell growth, foci formation in monolayer culture, colony formation in soft agar and tumorigenesis in nude mice. In addition, HN1L could also promote HCC metastasis by inducing epithelial-mesenchymal transition. Inversely, silencing HN1L expression with shRNA could effectively attenuate its oncogenic function. We further showed that HN1L transcriptionally up-regulated methyltransferase like 13 (METTL13) gene in an AP-2γ dependent manner, which promoted cell proliferation and metastasis by up-regulating TCF3 and ZEB1. Importantly, administration of lentivirus-mediated shRNA interfering HN1L expression could inhibit tumorigenesis and metastasis in mice. Collectively, HN1L-mediated transcriptional axis AP-2γ/METTL13/TCF3-ZEB1 promotes HCC growth and metastasis representing a promising therapeutic target in HCC treatment.

Li, Yang; Feng, Dongcheng; Wang, Zhanyu; Zhao, Yan; Sun, Ruimin; Tian, Donghai; Liu, Deshun; Zhang, Feng; Ning, Shili; Yao, Jihong; Tian, Xiaofeng

doi: 10.1038/s41418-019-0299-4pmid: 30737476

Ferroptosis is a recently identified form of regulated cell death defined by the iron-dependent accumulation of lipid reactive oxygen species. Ferroptosis has been studied in various diseases such as cancer, Parkinson’s disease, and stroke. However, the exact function and mechanism of ferroptosis in ischemia/reperfusion (I/R) injury, especially in the intestine, remains unknown. Considering the unique conditions required for ferroptosis, we hypothesize that ischemia promotes ferroptosis immediately after intestinal reperfusion. In contrast to conventional strategies employed in I/R studies, we focused on the ischemic phase. Here we verified ferroptosis by assessing proferroptotic changes after ischemia along with protein and lipid peroxidation levels during reperfusion. The inhibition of ferroptosis by liproxstatin-1 ameliorated I/R-induced intestinal injury. Acyl-CoA synthetase long-chain family member 4 (ACSL4), which is a key enzyme that regulates lipid composition, has been shown to contribute to the execution of ferroptosis, but its role in I/R needs clarification. In the present study, we used rosiglitazone (ROSI) and siRNA to inhibit ischemia/hypoxia-induced ACSL4 in vivo and in vitro. The results demonstrated that ACSL4 inhibition before reperfusion protected against ferroptosis and cell death. Further investigation revealed that special protein 1 (Sp1) was a crucial transcription factor that increased ACSL4 transcription by binding to the ACSL4 promoter region. Collectively, this study demonstrates that ferroptosis is closely associated with intestinal I/R injury, and that ACSL4 has a critical role in this lethal process. Sp1 is an important factor in promoting ACSL4 expression. These results suggest a unique and effective mechanistic approach for intestinal I/R injury prevention and treatment.

Zhang, Qi; Zhang, Ze-Yan; Du, Huan; Li, Shang-Ze; Tu, Rongfu; Jia, Yi-fan; Zheng, Zhe; Song, Xue-Min; Du, Run-Lei; Zhang, Xiao-Dong

doi: 10.1038/s41418-019-0303-zpmid: 30778200

The transcription factor nuclear factor (erythroid-derived 2)-like 2 (NRF2) is one of the master regulators that control hundreds of genes containing antioxidant response elements (AREs). The NRF2-ARE pathway plays a complex role in colorectal cancer (CRC). NRF2 activity is known to be regulated by KEAP1-CUL3 E3 ligase-mediated ubiquitination, indicating the importance of deubiquitination regulation. However, the deubiquitinase (DUB) of NRF2 remains unknown. Here, by screening a DUB library, we identified DUB3 as a DUB that remarkably stabilized NRF2. Further experiments demonstrated that DUB3 promoted NRF2 stability and transcriptional activity by decreasing the K48-linked ubiquitination of NRF2. Coimmunoprecipitation studies revealed interactions between NRF2 and DUB3, as well as between KEAP1 and DUB3, indicating that NRF2, DUB3, and KEAP1 formed a large functional complex. Importantly, ectopic expression of DUB3 caused NRF2-dependent chemotherapy resistance in colon cancer cell lines. Thus, to the best of our knowledge, our findings are the first to identify DUB3 as a NRF2 DUB and may provide a new strategy against chemotherapy resistance in CRC and other NRF2-related diseases.

Zhang, Chuan-xia; Ye, Shu-biao; Ni, Jian-jiao; Cai, Ting-ting; Liu, Yi-na; Huang, Dai-jia; Mai, Hai-qiang; Chen, Qiu-yan; He, Jia; Zhang, Xiao-shi; Zeng, Yi-xin; Li, Jiang; Cui, Jun

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