Relaxin induces an extracellular matrix-degrading phenotype in human lung fibroblasts in vitro and inhibits lung fibrosis in a murine model in vivo.
Year: 1996
Type: article
Abstract: Pulmonary fibrosis is the common end stage of a number of pneumopathies.In this study, we examined the ability of the human cytokine, relaxin, to block extracellular matrix deposition by human lung fibroblasts in vitro, and to inhibit lung fibrosis in a bleomycin-induced murine model.In vitro, relaxin (1-100 ng/ml) inhibited the transforming growth factor- -mediated over-expression of interstitial collagen types I and III by human lung fibroblasts by up to 45% in a dose-dependent manner.Relaxin did not affect basal levels of collagen expression in the absence of TGF- -induced stimulation.Relaxin also blocked transforming growth factor- -induced upregulation of fibronectin by 80% at the highest relaxin dose tested (100 ng/ml).The expression of matrix metalloproteinase-1, or procollagenase, was stimulated in a biphasic, dose-dependent manner by relaxin.In vivo, relaxin, at a steady state circulating concentration of ف 50 ng/ml, inhibited bleomycin-mediated alveolar thickening compared with the vehicle only control group ( P Ͻ 0.05).Relaxin also restored bleomycin-induced collagen accumulation, as measured by lung hydroxyproline content, to normal levels ( P Ͻ 0.05).In summary, relaxin induced a matrix degradative phenotype in human lung fibroblasts in vitro and inhibited bleomycin-induced fibrosis in a murine model in vivo.These data indicate that relaxin may be efficacious in the treatment of pathologies characterized by lung fibrosis.( J. Clin.Invest.1996.98:2739-2745) Key words: pulmonary fibrosis • relaxin • collagen • collagenase MethodsCell culture.Normal human lung fibroblasts obtained from young adult donors were purchased from the American Type Culture Collection (ATCC CCL202, CCL210; Rockville, MD) and passaged according to vendor instructions in MEM supplemented with 10% fetal bovine serum, nonessential amino acids, and 2 mM L-glutamine.Cells were seeded at a density of 1.25 ϫ 10 5 cells/cm 2 in the presence of serum but were switched to MEM supplemented with 0.2% lactalbumin hydrolysate and 2 mM L-glutamine (MEM-LH) for experiments.Reagents and animals.Recombinant human relaxin (Lot M3R-D211 or 9997-96) was manufactured at Genentech, Inc. (South San Francisco, CA) [ 3 H]proline (43 Ci/mmol) was purchased from Amersham (Arlington Heights, IL).Ascorbic acid and  -aminopropionitrile (BAPN) were purchased from Sigma Chemical Co.(St.Louis, MO) and prepared immediately before use as 50 and 80 mg/ml stocks, respectively.Bleomycin (15 U/vial, Blenoxane) (Burns Veterinary
DOI: 10.1172/jci119099
Language: English
Subfield: Pulmonary and Respiratory Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
Funder: University of Washington
OpenAlex ID: W2018314711