title: Atrial natriuretic peptide stimulates the expression of transforming growth factor-beta in cultured murine mesangial cells: relationship to suppression of proliferation.
abstract: Atrial natriuretic peptide (ANP) is a growth suppressor for a variety of different cell types including cultured mesangial cells. This study examined the effects of ANP on the expression and synthesis of transforming growth factor-beta (TGF-beta) in a cultured murine mesangial cell line (MMC). Full-length rat ANP as well as 8-bromo-cGMP, but not ring-deleted ANP analogues, induced, in a dose-dependent manner, TGF-beta 1 mRNA expression in MMC. Moreover, full-length ANP and 8-bromo-cGMP stimulated the synthesis and release of TGF-beta 1 into cell culture supernatants as measured by a specific enzyme-linked immunosorbent assay and mink cell bioassay. The induction of TGF-beta 1 by 10(-6) M ANP and 10(-4) M 8-bromo-cGMP for 24 h was also documented by western blotting of MMC culture supernatants. However, transient transfection studies in MMC with three different murine TGF-beta 1 reporter gene constructs revealed only little stimulation of activity after ANP treatment, suggesting that posttranscriptional activation may mainly contribute to TGF-beta mRNA induction. Functional studies demonstrated that the ANP-mediated inhibition of mitosis, induced by 5% fetal calf serum, is partly abolished in the presence of a neutralizing anti-TGF-beta 1-3 antibody. In addition, the antiproliferative effects of exogenous 8-bromo-cGMP are also attenuated by anti-TGF-beta 1-3 antibody. These findings indicate that ANP stimulates TGF-beta expression in MMC and that the antiproliferative effects of ANP in this cell line may be mediated, at least to some extent, by the endogenous induction of TGF-beta. An increase in intracellular cGMP is most likely the mediator of this TGF-beta 1 induction. Considering the fibrogenic effects of TGF-beta, these findings may be important in the development of glomerulosclerosis in situations with an increase in local or systemic ANP.
authors.affiliation: Department of Medicine, University of Hamburg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Wolf
authors.forename: F N
authors.initials: FN
authors.lastname: Ziyadeh
authors.forename: R A
authors.initials: RA
authors.lastname: Stahl
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D009320:Atrial Natriuretic Factor / Q000276:immunology*; D015152:Blotting, Northern; D015153:Blotting, Western; D002455:Cell Division; D002461:Cell Line, Transformed; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000276:immunology; D004306:Dose-Response Relationship, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay; D005920:Glomerular Mesangium / Q000166:cytology* / Q000276:immunology*; D051379:Mice; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000911:Antibodies, Monoclonal; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; C016276:8-bromocyclic GMP; D009320:Atrial Natriuretic Factor; D006152:Cyclic GMP