title: Pioglitazone inhibits cell growth and reduces matrix production in human kidney fibroblasts.
abstract: Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) agonists are increasingly used in patients with diabetes, and small studies have suggested a beneficial effect on renal function, but their effects on extracellular matrix (ECM) turnover are unknown. The aims of this study were to investigate the effects of the PPAR-gamma agonist pioglitazone on growth and matrix production in human cortical fibroblasts (CF). Cell growth and ECM production and turnover were measured in human CF in the presence and absence of 1 and 3 muM pioglitazone. Exposure of CF to pioglitazone caused an antiproliferative (P < 0.0001) and hypertrophic (P < 0.0001) effect; reduced type IV collagen secretion (P < 0.01), fibronectin secretion (P < 0.0001), and proline incorporation (P < 0.0001); decreased MMP-9 activity (P < 0.05); and reduced tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 secretion (P < 0.001 and P < 0.0001, respectively). These effects were independent of TGF-beta1. A reduction in ECM production was similarly observed when CF were exposed to a selective PPAR-gamma agonist (L-805645) in concentrations that caused no toxicity, confirming the antifibrotic effects of pioglitazone were mediated through a PPAR-gamma-dependent mechanism. Exposure of CF to high glucose conditions induced an increase in the expression of collagen IV (P < 0.05), which was reversed both in the presence of pioglitazone (1 and 3 muM) and by L-805645. In summary, exposure of human CF to pioglitazone causes an antiproliferative effect and reduces ECM production through mechanisms that include reducing TIMP activity, independent of TGF-beta1. These studies suggest that the PPAR-gamma agonists may have a specific role in ameliorating the course of progressive tubulointerstitial fibrosis under both normoglycemic and hyperglycemic states.
authors.affiliation: Department of Medicine, University of Sydney, Kolling Institute of Medical Research, Royal North Shore Hospital, St. Leonards, Sydney, NSW 2065, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Zafiriou
authors.forename: Scott R
authors.initials: SR
authors.lastname: Stanners
authors.forename: Sonia
authors.initials: S
authors.lastname: Saad
authors.forename: Tania S
authors.initials: TS
authors.lastname: Polhill
authors.forename: Philip
authors.initials: P
authors.lastname: Poronnik
authors.forename: Carol A
authors.initials: CA
authors.lastname: Pollock
mesh_terms: D016923:Cell Death / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D024141:Collagen Type IV / Q000378:metabolism; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D005947:Glucose / Q000494:pharmacology; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D066298:In Vitro Techniques; D007672:Kidney Cortex / Q000166:cytology*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D047495:PPAR gamma / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D000077205:Pioglitazone; D011392:Proline / Q000378:metabolism; D045162:Thiazolidinediones / Q000494:pharmacology*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism; D053773:Transforming Growth Factor beta1
chemical_list: D024141:Collagen Type IV; D005353:Fibronectins; D007004:Hypoglycemic Agents; D047495:PPAR gamma; C508960:TGFB1 protein, human; D045162:Thiazolidinediones; D019715:Tissue Inhibitor of Metalloproteinase-1; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D019716:Tissue Inhibitor of Metalloproteinase-2; D011392:Proline; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D005947:Glucose; D000077205:Pioglitazone