BACKGROUND: Curcumin, a polyphenolic compound derived from rhizomes of Curcuma spp., has been shown to possess potent anti-fibrotic properties. Here, we investigate the role of curcumin in modulating the profibrotic action of TGF-beta in human proximal tubule cells (HK-2) and its underlying mechanisms. METHODS: HK-2 cells were stimulated with 5 ng/ml TGF-beta(1). The effects of curcumin on TGF-beta(1)-regulated gene expression and Smad phosphorylation were analyzed by RT-PCR, ELISA and Western blotting. RESULTS: Curcumin inhibited TGF-beta(1)-induced plasminogen activator inhibitor-1 (PAI-1), alpha-smooth muscle actin (alpha-SMA) mRNA and protein expression. Curcumin suppressed not only TGF-beta(1)-induced Smad2 phosphorylation in a dose- and time-dependent manner, but also the nuclear accumulation of receptor-regulated Smads (R-Smad), Smad2 and Smad3. A serine/threonine protein phosphatase inhibitor (microcystin) could partly reverse the inhibitory effect of curcumin on Smad phosphorylation. CONCLUSIONS: Curcumin blocks the profibrotic actions of TGF-beta on HK-2 cells through the down-regulation of the Smad signaling pathway, and curcumin may have some similar effect as serine/threonine protein phosphatases. Our findings suggest curcumin as a potential candidate for treatment of tubulointerstitial fibrosis. 2010 S. Karger AG, Basel.
BACKGROUND:Curcumin, a polyphenolic compound derived from rhizomes of Curcuma spp., has been shown to possess potent anti-fibrotic properties. Here, we investigate the role of curcumin in modulating the profibrotic action of TGF-beta in human proximal tubule cells (HK-2) and its underlying mechanisms. METHODS: HK-2 cells were stimulated with 5 ng/ml TGF-beta(1). The effects of curcumin on TGF-beta(1)-regulated gene expression and Smad phosphorylation were analyzed by RT-PCR, ELISA and Western blotting. RESULTS:Curcumin inhibited TGF-beta(1)-induced plasminogen activator inhibitor-1 (PAI-1), alpha-smooth muscle actin (alpha-SMA) mRNA and protein expression. Curcumin suppressed not only TGF-beta(1)-induced Smad2 phosphorylation in a dose- and time-dependent manner, but also the nuclear accumulation of receptor-regulated Smads (R-Smad), Smad2 and Smad3. A serine/threonine protein phosphatase inhibitor (microcystin) could partly reverse the inhibitory effect of curcumin on Smad phosphorylation. CONCLUSIONS:Curcumin blocks the profibrotic actions of TGF-beta on HK-2 cells through the down-regulation of the Smad signaling pathway, and curcumin may have some similar effect as serine/threonine protein phosphatases. Our findings suggest curcumin as a potential candidate for treatment of tubulointerstitial fibrosis. 2010 S. Karger AG, Basel.
Authors: Laura E Wright; Jennifer B Frye; Ashley L Lukefahr; Barbara N Timmermann; Khalid S Mohammad; Theresa A Guise; Janet L Funk Journal: J Nat Prod Date: 2012-11-12 Impact factor: 4.050
Authors: Matthew A Weir; Michael Walsh; Meaghan S Cuerden; Jessica M Sontrop; Laura C Chambers; Amit X Garg Journal: Can J Kidney Health Dis Date: 2018-12-05