American Journal of Respiratory Cell and Molecular Biology

Cohn, Lauren

doi: 10.1165/ajrcmb.24.5.f207pmid: 11350818

Wright, Jo Rae; Borron, Paul; Brinker, Karen G.; Folz, Rodney J.

doi: 10.1165/ajrcmb.24.5.f208pmid: 11350819

Russo, Momtchilo; Nahori, Marie-Anne; Lefort, Jean; Gomes, Eliane; de Castro Keller, Alexandre; Rodriguez, Dunia; Ribeiro, Orlando Garcia; Adriouch, Sahil; Gallois, Vallerie; de Faria, Ana M. C.; Vargaftig, B. Boris

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Yang, Shuxia; Milla, Carlos; Panoskaltsis-Mortari, Angela; Ingbar, David H.; Blazar, Bruce R.; Haddad, Imad Y.

doi: 10.1165/ajrcmb.24.5.4400pmid: 11350821

We have previously shown an association between growth factor–induced upregulation of surfactant protein (SP)-A and suppression of alveolar inflammation in our murine model of donor T cell–dependent lung dysfunction after bone-marrow transplantation, referred to as idiopathic pneumonia syndrome (IPS). We hypothesized that SP-A protects the lung in vivo from IPS injury by downregulation of alveolar inflammation. Human SP-A (100 μ g), purified by n-butanol extraction or preparative isoelectric focusing, was transtracheally instilled on Day 4 after BMT during a time of in vivo donor T-cell activation. At 48 h after treatment, immunohistochemical staining of lung sections showed that SP-A did not alter T cell–dependent cellular infiltration. However, macrophages from SP-A–instilled mice were less injured and spontaneously produced less tumor necrosis factor-α than did cells from buffer-instilled mice. Although exogenous SP-A did not significantly alter bronchoalveolar lavage fluid (BALF) high levels of total protein (TP), an inverse correlation between BALF SP-A and TP concentrations (r = − 0.65; P = 0.02) was observed in SP-A–treated but not in buffer-instilled mice. The only difference between the effects of the two sources of SP-A was that butanol-extracted SP-A, but not isoelectric focusing–purified SP-A, suppressed the interferon-γ /nitric oxide pathway. We conclude that SP-A downregulates T cell–dependent alveolar inflammation by multiple pathways leading to decreased IPS injury.

Warner, Roscoe L.; Beltran, Luis; Younkin, Ellen M.; Lewis, Clarence S.; Weiss, Stephen J.; Varani, James; Johnson, Kent J.

doi: 10.1165/ajrcmb.24.5.4160pmid: 11350822

Matrix metalloproteinases (MMPs) are upregulated locally in sites of inflammation, including the lung. Several MMP activities are upregulated in acute lung injury models but the exact role that these MMPs play in the development of the lung injury is unclear due to the absence of specific inhibitors. To determine the involvement of individual MMPs in the development of lung injury, mice genetically deficient in gelatinase B (MMP-9) and stromelysin 1 (MMP-3) were acutely injured with immunoglobulin G immune complexes and the intensity of the lung injury was compared with genetically identical wild-type (WT) mice with normal MMP activities. In the WT mice there was upregulation of gelatinase B and stromelysin 1 in the injured lungs which, as expected, was absent in the genetically deficient gelatinase B–and stromelysin 1–deficient mice, respectively. In the deficient mice there was little in the way of compensatory upregulation of other MMPs. The gelatinase B–and the stromelysin 1–deficient mice had less severe lung injury than did the WT controls, suggesting that both MMPs are involved in the pathogenesis of the lung injury. Further, the mechanism of their involvement in the lung injury appears to be different, with the stromelysin 1–deficient mice having a reduction in the numbers of neutrophils recruited into the lung whereas the gelatinase B–deficient mice had the same numbers of lung neutrophils as did the injured WT controls. These studies indicate, first, that both gelatinase B and stromelysin 1 are involved in the development of experimental acute lung injury, and second, that the mechanisms by which these individual MMPs function appear to differ.

Chen, Edward S.; Greenlee, Brian M.; Wills-Karp, Marsha; Moller, David R.

doi: 10.1165/ajrcmb.24.5.4064pmid: 11350823

Because mouse strains susceptible to bleomycin, such as C57BL/6J, tend to produce T helper type 1 (Th1) cytokines in response to immune activation, we hypothesized that the inflammatory response to bleomycin is mediated, in part, by local production of the Th1 cytokine interferon-γ (IFN-γ ). Consistent with this hypothesis, fibrosis-prone C57BL/6J and A/J mice demonstrated significantly elevated expression of IFN-γ protein (by enzyme-linked immunosorbent assay) in bronchoalveolar lavage fluid at 24 h, and subsequently increased lung inflammation, weight loss, and mortality 10 d after intratracheal bleomycin administration compared with fibrosis-resistant BALB/c mice or saline control mice. To directly determine a role for IFN-γ in bleomycin toxicity, we exposed C57BL/6J mice with a homozygous null mutation of the IFN-γ gene (IFN-γ [ − / − ]) and wild-type C57BL/6J mice to intratracheal bleomycin. IFN-γ ( − / − ) mice demonstrated significantly lower parenchymal inflammation, weight loss, and mortality 10 d after 5 U/kg intratracheal bleomycin administration compared with control mice. At 3 wk after 1.5 U/kg bleomycin exposure, single lung collagen determined by hydroxyproline assay was significantly lower in IFN-γ ( − / − ) mice compared with wild-type C57BL/6J mice. Together, these results suggest that IFN-γ mediates, in part, bleomycin-induced pulmonary inflammation and fibrosis.

Pilewski, Joseph M.; Bumbalo, Thomas S.; Davis, Autumn Gaither; Siegfried, Jill M.

doi: 10.1165/ajrcmb.24.5.4074pmid: 11350824

Significant progress has been made toward identifying growth factors that display autocrine or paracrine effects on the growth of lung cancer cells. Determining the in vivo relevance of specific growth factors on lung tumor formation, however, has not often been demonstrated in laboratory models. Although hepatocyte growth factor (HGF) has been shown to have mitogenic and motogenic effects on human lung cancer cells in vitro, and to have prognostic importance in patients with lung cancer, the effects of HGF on tumor behavior in vivo remain unknown. We therefore developed an airway tumor xenograft model that allowed us to test the hypothesis that HGF promotes human non–small cell lung cancer (NSCLC) growth in vivo. Human airway tumor xenografts were created in Severe Combined Immunodeficient mice by injecting human lung adenocarcinoma cells into human bronchial segments. After determining the optimal times for tumor-cell injection and the time course of tumor growth, we evaluated the effects of HGF on tumor growth by injecting recombinant HGF, or saline as a control, into the lumen of tumor xenografts for 10 consecutive days. Histologic evaluation 2 to 3 wk later revealed that the HGF-injected xenografts had a significantly greater tumor volume and more tumor cells were located in the submucosal space than were found in the saline-injected xenografts. These data demonstrate the usefulness of this novel in vivo model to study NSCLC, and show that HGF promotes both the growth and invasion of human lung cancer in vivo.

Burr, John S.; Kimzey, Stephanie L.; Randolph, David R.; Green, Jonathan M.

doi: 10.1165/ajrcmb.24.5.4375pmid: 11350825

Airway inflammation after inhaled allergen exposure requires the recruitment, activation, and differentiation of antigen-specific T cells into T helper (Th) 2 effector cells. These processes are regulated not only by antigen engagement of the T-cell receptor, but also by specific accessory molecules on the surface of the T cell. We examined how the balance of signals derived through the CD28 and cytotoxic T-lymphocyte antigen (CTLA) 4 receptors modulate the outcome of inhaled antigen exposure in a murine model of allergic airway inflammation. Mice deficient in CD28 have defective Th2 cell development and failed to develop inflammation after sensitization and inhaled challenge with ovalbumin. Prevention of B7–CTLA4 interactions in CD28-deficient mice restored lymphocyte but not eosinophil recruitment to the airway. Analysis of cytokine gene expression revealed that T cells from CD28-deficient mice failed to differentiate into Th2 cells in either the presence or absence of B7-dependent signals, and therefore did not recruit eosinophils to the airway. Thus, the processes of T-cell recruitment to the airway and T-cell differentiation have distinct requirements for signals mediated through the CD28 and CTLA4 receptors, demonstrating that these receptors are important regulatory components in the development of allergic airway inflammation.

Vernooy, Juanita H. J.; Dentener, Mieke A.; van Suylen, Robert Jan; Buurman, Wim A.; Wouters, Emiel F. M.

doi: 10.1165/ajrcmb.24.5.4156pmid: 11350826

This study investigated apoptosis in lungs after local exposure to lipopolysaccharide (LPS). Mice were instilled intratracheally with 5 μ g LPS, which corresponds to the amount acquired by smoking approximately 25 cigarettes, and killed at different time points after exposure. Our data demonstrate that local LPS exposure resulted in apoptosis in lungs from 2 h and peaked at 24 h, as detected by ligation-mediated polymerase chain reaction. Morphologic examination and terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick-end label staining demonstrated apoptosis in bronchial epithelial cells early after intratracheal (IT) LPS challenge, whereas infiltrating neutrophils displayed positive staining at 24 and 72 h after exposure. Apoptosis in lungs clearly preceded pulmonary neutrophil infiltration, confirming that neutrophils did not contribute to pulmonary apoptosis at early time points. Further, using three experimental approaches—namely, anti–tumor necrosis factor (TNF)-α treatment, IT TNF-α instillation, and TNF/lymphotoxin-α knockout mice—we demonstrate that TNF-α, which was elevated in lungs at both messenger RNA and protein levels after IT LPS challenge, was no primary mediator in LPS-induced apoptosis at early time points. Thus, local LPS exposure in mice resulted in early apoptosis of bronchial epithelial cells independent of infiltrating neutrophils and TNF-α, which suggests that apoptosis of bronchial epithelium may be involved in airway injury during exposure to LPS.

Martin, Richard J.; Chu, Hong Wei; Honour, Joyce M.; Harbeck, Ronald J.

doi: 10.1165/ajrcmb.24.5.4315pmid: 11350827

The interaction between chronic infection and chronic asthma is receiving increased investigation as a factor in the pathophysiology of asthma. To further understand this interaction, we used an animal model (BALB/c mice) with a Mycoplasma pneumoniae respiratory infection. Mice were studied 3, 7, 14, and 21 d after infection. Bronchial hyperresponsiveness (BHR) was assessed by methacholine challenge and was significantly heightened in the infected mice compared with saline controls at Days 3, 7, and 14. The associated inflammatory response was mainly neutrophils. The tissue inflammatory score significantly correlated to BHR (r = 0.78, P < 0.0001). Additionally, tissue interferon (IFN)-γ was significantly suppressed at Days 3 and 7 in the infected group compared with controls; and at Days 3, 7, and 14 compared with Day 21 in the infected group. There was a significant negative correlation between lung tissue messenger RNA levels of IFN-γ corrected for β-actin and BHR (r = − 0.50, P = 0.022). Thus, M. pneumoniae respiratory infection is associated with BHR in this murine model. It appears that acute mycoplasma infection suppresses IFN-γ, which may be a pivotal factor in the control of BHR.