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Pulmonary fibrosis remains a serious biomedical problem with no cure and an urgent need for better therapies. Neuraminidases (NEUs), including NEU1, have been recently implicated in the mechanism of pulmonary fibrosis by us and others. We now have tested the ability of a broad-spectrum neuraminidase inhibitor, 2,3-dehydro-2-deoxy- N -acetylneuraminic acid (DANA), to modulate the in vivo response to acute intratracheal bleomycin challenge as an experimental model of pulmonary fibrosis. A marked alleviation of bleomycin-induced body weight loss and notable declines in accumulation of pulmonary lymphocytes and collagen deposition were observed. Real-time polymerase chain reaction analyses of human and mouse lung tissues and primary human lung fibroblast cultures were also performed. A predominant expression and pronounced elevation in the levels of NEU1 mRNA were observed in patients with idiopathic pulmonary fibrosis and bleomycin-challenged mice compared with their corresponding controls, whereas NEU2, NEU3, and NEU4 were expressed at far lower levels. The levels of mRNA for the NEU1 chaperone, protective protein/cathepsin A (PPCA), were also elevated by bleomycin. Western blotting analyses demonstrated bleomycin-induced elevations in protein expression of both NEU1 and PPCA in mouse lungs. Two known selective NEU1 inhibitors, C9-pentyl-amide-DANA (C9-BA-DANA) and C5-hexanamido-C9-acetamido-DANA, dramatically reduced bleomycin-induced loss of body weight, accumulation of pulmonary lymphocytes, and deposition of collagen. Importantly, C9-BA-DANA was therapeutic in the chronic bleomycin exposure model with no toxic effects observed within the experimental timeframe. Moreover, in the acute bleomycin model, C9-BA-DANA attenuated NEU1-mediated desialylation and shedding of the mucin-1 ectodomain. These data indicate that NEU1-selective inhibition offers a potential therapeutic intervention for pulmonary fibrotic diseases. SIGNIFICANCE STATEMENT: Neuraminidase-1-selective therapeutic targeting in the acute and chronic bleomycin models of pulmonary fibrosis reverses pulmonary collagen deposition, accumulation of lymphocytes in the lungs, and the disease-associated loss of body weight-all without observable toxic effects. Such therapy is as efficacious as nonspecific inhibition of all neuraminidases in these models, thus indicating the central role of neuraminidase-1 as well as offering a potential innovative, specifically targeted, and safe approach to treating human patients with a severe malady: pulmonary fibrosis., (U.S. Government work not protected by U.S. copyright.)

Background: Overlapping forms of interstitial pneumonia have been recognized, but are likely underappreciated, and their clinical, radiologic, and histologic characteristics are not well-defined., Methods: We identified 38 patients with surgical lung biopsy demonstrating histologic organizing pneumonia (OP) or histologic organizing pneumonia/non-specific interstitial pneumonia overlap (OP/NSIP) who met established multi-disciplinary clinical-radiologic-histologic criteria for OP. For each patient, radiologic and co-histologic findings were assessed, and clinical outcome was characterized as disease resolution (complete or near-complete resolution of radiologic opacities and absence of chronic respiratory symptoms) or unfavorable disease progression (death due to respiratory failure or forced vital capacity < 70% predicted > six months from diagnosis)., Results: Seven of 38 patients had clinical-radiologic-histologic focal OP. Focal OP was associated with histologic OP (p = 0.019), and all seven patients demonstrated disease resolution. In the remaining 31 patients with cryptogenic or autoimmune-associated OP, 21 patients had histologic OP/NSIP, and 10 had histologic OP. Histologic OP/NSIP was associated with ground glass opacity (GGO, p = 0.012), reticulation (p = 0.029), traction bronchiectasis (p = 0.029), reactive pneumocytes (p = 0.013), and unfavorable disease progression (p < 0.0001). Histologic OP was associated with consolidation (p = 0.028) and disease resolution (p < 0.0001). Multivariate analysis demonstrated histologic OP/NSIP (p < 0.001) and radiologic GGO (p = 0.041) to be independently associated with unfavorable disease progression., Conclusions: OP/NSIP overlap, either idiopathic or autoimmune-associated and identified by histologic and radiologic findings, was associated with unfavorable disease progression, and should therefore be recognized as a characteristic clinical-radiologic-histologic entity., (Published by Elsevier Ltd.)

Interstitial lung disease (ILD) characterized by pulmonary fibrosis and inflammation poses a substantial biomedical challenge due to often negative disease outcomes combined with the need to develop better, more effective therapies. We assessed the in vivo effect of administration of a pharmacological inhibitor of S-nitrosoglutathione reductase, SPL-334 (4-{[2-[(2-cyanobenzyl)thio]-4-oxothieno[3,2-d]pyrimidin-3(4H)-yl]methyl}benzoic acid), in a mouse model of ILD induced by intratracheal instillation of bleomycin (BLM). Daily i.p. administration of SPL-334 alone at 0.3, 1.0, or 3.0 mg/kg had no effect on animal body weight, appearance, behavior, total and differential bronchoalveolar lavage (BAL) cell counts, or collagen accumulation in the lungs, showing no toxicity of our investigational compound. Similar administration of SPL-334 for 7 days before and for an additional 14 days after BLM instillation resulted in a preventive protective effect on the BLM challenge-induced decline in total body weight and changes in total and differential BAL cellularity. In the therapeutic treatment regimen, SPL-334 was administered at days 7-21 after BLM challenge. Such treatment attenuated the BLM challenge-induced decline in total body weight, changes in total and differential BAL cellularity, and magnitudes of histologic changes and collagen accumulation in the lungs. These changes were accompanied by an attenuation of BLM-induced elevations in pulmonary levels of profibrotic cytokines interleukin-6, monocyte chemoattractant protein-1, and transforming growth factor-β (TGF-β). Experiments in cell cultures of primary normal human lung fibroblast have demonstrated attenuation of TGF-β-induced upregulation in collagen by SPL-334. It was concluded that SPL-334 is a potential therapeutic agent for ILD., (Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.)

Oncostatin M (OSM), an IL-6 family cytokine, has been implicated in a number of biological processes including the induction of inflammation and the modulation of extracellular matrix. In this study, we demonstrate that OSM is up-regulated in the bronchoalveolar lavage fluid of patients with idiopathic pulmonary fibrosis and scleroderma, and investigate the pathological consequences of excess OSM in the lungs. Delivery of OSM to the lungs of mice results in a significant recruitment of inflammatory cells, as well as a dose-dependent increase in collagen deposition in the lungs, with pathological correlates to characteristic human interstitial lung disease. To better understand the relationship between OSM-induced inflammation and OSM-induced fibrosis, we used genetically modified mice and show that the fibrotic response is largely independent of B and T lymphocytes, eosinophils, and mast cells. We further explored the mechanisms of OSM-induced inflammation and fibrosis using both protein and genomic array approaches, generating a "fibrotic footprint" for OSM that shows modulation of various matrix metalloproteinases, extracellular matrix components, and cytokines previously implicated in fibrosis. In particular, although the IL-4/IL-13 and TGF-beta pathways have been shown to be important and intertwined of fibrosis, we show that OSM is capable of inducing lung fibrosis independently of these pathways. The demonstration that OSM is a potent mediator of lung inflammation and extracellular matrix accumulation, combined with the up-regulation observed in patients with pulmonary fibrosis, may provide a rationale for therapeutically targeting OSM in human disease.

Elevated pulmonary levels of CCL18 have been associated with influx of T lymphocytes, collagen accumulation, and a decline in lung function in pulmonary fibrosis patients. We previously reported that overexpression of CCL18 in mouse lungs triggers selective infiltration of T lymphocytes and moderate lymphocyte-dependent collagen accumulation. We hypothesized that in combination with bleomycin injury, overexpression of CCL18 will worsen the severity of lung inflammation and fibrosis. Mice were infected with a replication-deficient adenovirus encoding CCL18 and then instilled with bleomycin; control mice were challenged with either CCL18 overexpression or bleomycin. Additive effects of CCL18 overexpression and bleomycin injury were observed on pulmonary inflammation, particularly on T-cell infiltration, and increased levels of tumor necrosis factor-alpha, interferon-gamma, matrix metalloproteinase (MMP)-2, and MMP-9. Despite the additive effect on inflammation, CCL18 overexpression unexpectedly attenuated the bleomycin-induced collagen accumulation. Pulmonary levels of active transforming growth factor-beta1 mirrored the changes in collagen levels. Depletion of T cells with antilymphocyte serum or pharmacological inhibition of MMPs with GM6001 abrogated accumulation of collagen and increases in the levels of tumor necrosis factor-alpha, interferon-gamma, and active transforming growth factor-beta1. Thus, CCL18-stimulated T-lymphocytic infiltration is by itself mildly profibrotic to a healthy lung, whereas it partially protects against lung fibrosis in an inflammatory profibrotic pulmonary milieu.

The hypothesis of this study is that activation of cell-mediated immunity with associated macrophage activation occurs in the lungs of scleroderma patients with lung inflammation. Gene expression profiles were determined in bronchoalveolar lavage (BAL) cells from scleroderma patients with and without lung inflammation and control subjects, using DNA array technology. Enzyme-linked immunosorbent assay was used to measure proteins in BAL fluids. Gene expression profiles were similar in BAL cells from patients without lung inflammation and control subjects. Gene expression profiles in patients with lung inflammation showed increased expression of chemokines and chemokine receptor genes, which would lead to migration of T cells, especially type 2 T cells, and phagocytic cells. Protein levels of pulmonary and activated-response chemokine and monocyte chemoattractant protein-1 were elevated. Other changes in gene expression suggested alterations in gene transcription, cell cycle control, vesicle transport, antigen-presenting function, and intracellular signaling. Two anti-inflammatory cytokines, interleukin-1 receptor antagonist and transforming growth factor-beta1, had increased expression, consistent with other human fibrotic lung diseases and animal models of lung fibrosis. These findings suggest recruitment of T cells and chronic macrophage activation in scleroderma patients at greater risk for lung fibrosis, but differ from typical delayed-type hypersensitivity responses, without prominence of type 1 T cells and inflammatory cytokines.