Aldosterone and TGF-beta1 synergistically increase PAI-1 and decrease matrix degradation in rat renal mesangial and fibroblast cells.
Aldosterone is thought to modulate renal fibrosis, in part, through increasing plasminogen activator inhibitor type 1 (PAI-1), a major inhibitor of ECM degradation. The present study investigated aldosterone effects on PAI-1 and transforming growth factor (TGF)-beta(1) and asked whether PAI-1 effects were TGF-beta mediated and whether aldosterone and TGF-beta(1) acted synergistically to increase PAI-1 and decrease ECM degradation. Rat mesangial cells (MCs) and fibroblast cells [normal rat kidney (NRK)-49F] were used. (3)H-labeled ECM was produced by MCs. The effect of aldosterone and TGF-beta on ECM degradation by newly plated MCs or NRK-49F was measured by the release of (3)H into medium. Aldosterone markedly increased PAI-1 mRNA and protein in both cell types, increases completely blocked by spironolactone and partially blocked by TGF-beta neutralizing antibody. Adding both aldosterone and TGF-beta(1) produced PAI-1 mRNA and protein increases higher than the sum of increases seen with either compound alone. Aldosterone or TGF-beta(1) alone inhibited matrix degradation by 39 and 49% in MCs and 21 and 23% in NRK-49F, respectively. When both compounds were added, matrix degradation was further decreased by 93% in MCs and 61% in NRK-49F. The results indicate that aldosterone-induced PAI-1 increases are partially mediated by TGF-beta(1) and lead to decreased ECM degradation. While aldosterone alone induced TGF-beta(1) weakly, aldosterone and TGF-beta(1) added together produced dramatic synergistic effects on PAI-1 production and subsequent ECM accumulation. Thus the elevated aldosterone induced by renin-angiotensin-aldosterone system activation may amplify renin-angiotensin-aldosterone system profibrotic actions.
Huang
Wei
W
Fibrosis Research Laboratory, Division of Nephrology, University of Utah School of Medicine, Salt Lake City, UT 84108, USA.
Xu
Chen
C
Kahng
Kyoung W
KW
Noble
Nancy A
NA
Border
Wayne A
WA
Huang
Yufeng
Y
D000450:Aldosterone / Q000494:pharmacology*; D000818:Animals; D002478:Cells, Cultured; D004357:Drug Synergism; D005109:Extracellular Matrix / Q000187:drug effects / Q000473:pathology / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D005355:Fibrosis; D015870:Gene Expression / Q000187:drug effects; D007674:Kidney Diseases / Q000473:pathology / Q000503:physiopathology; D050527:Mesangial Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D053773:Transforming Growth Factor beta1 / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology
D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D053773:Transforming Growth Factor beta1; D000450:Aldosterone