title: Relaxin modulates synthesis and secretion of procollagenase and collagen by human dermal fibroblasts.
abstract: Relaxin is believed to play a role in connective tissue remodeling during pregnancy (Bell, R.J., Eddie, L. W., Lester, A. R., Wood, E. C., Johnston, P.D., and Niall, H. D. (1987) Obstet. Gynecol. 69, 585-589; MacLennan, A. H. (1983) Clin. Reprod. Fertil. 2, 77-95). In the present study, normal human fibroblasts exposed to concentrations of a synthetic bioactive relaxin peptide from 0.1 to 10 ng/ml synthesized and secreted the metalloproteinase procollagenase, which was immunoprecipitable as a doublet of 52 and 57 kDa by a monoclonal antibody to human collagenase. The stimulation in procollagenase protein expression was reflected in an elevation in procollagenase mRNA levels. Media conditioned for 48 h by relaxin-treated fibroblasts (0.1 ng/ml) contained 1.7 units/ml activatable collagenase compared with 0.2 units/ml by untreated fibroblasts. In addition, relaxin caused a modest decrease in the levels of tissue inhibitor of metalloproteinases, as detected by reverse zymography and Northern analysis. Relaxin was also a potent modulator of the collagen secretory phenotype of these fibroblasts. Relaxin at 100 ng/ml down-regulated collagen secretion by 40%. When fibroblasts were treated simultaneously with cytokines such as transforming growth factor beta or interleukin 1 beta, which stimulated collagen synthesis to at least 9-fold of basal levels, relaxin at 100 ng/ml was able to down-regulate collagen expression by up to 88%. This decrease was reflected by changes at the mRNA level. These results indicate that relaxin can cause significant collagen turnover both by stimulating collagenase expression and by down-modulating collagen synthesis and secretion.
authors.affiliation: Department of Developmental Biology, Genentech, Inc., South San Francisco, California 94080.
authors.forename: E N
authors.initials: EN
authors.lastname: Unemori
authors.forename: E P
authors.initials: EP
authors.lastname: Amento
mesh_terms: D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis* / Q000378:metabolism; D017364:Collagenases; D004792:Enzyme Precursors / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism; D006023:Glycoproteins / Q000096:biosynthesis / Q000302:isolation & purification; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007700:Kinetics; D003012:Microbial Collagenase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D008970:Molecular Weight; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D011994:Recombinant Proteins / Q000494:pharmacology; D012065:Relaxin / Q000494:pharmacology*; D012867:Skin / Q000378:metabolism*; D019714:Tissue Inhibitor of Metalloproteinases; D015291:Transforming Growth Factors / Q000494:pharmacology
chemical_list: D004792:Enzyme Precursors; D006023:Glycoproteins; D007375:Interleukin-1; D012333:RNA, Messenger; D011994:Recombinant Proteins; D019714:Tissue Inhibitor of Metalloproteinases; D015291:Transforming Growth Factors; D012065:Relaxin; D003094:Collagen; D017364:Collagenases; C022440:procollagenase; D003012:Microbial Collagenase