Low-dose paclitaxel ameliorates renal fibrosis in rat UUO model by inhibition of TGF-β/Smad activity

Department of Nephrology, Second Xiangya Hospital, Central South University, Changsha, Hunan, PR China.
Laboratory Investigation (Impact Factor: 3.83). 02/2010; 90(3):436-47. DOI: 10.1038/labinvest.2009.149
Source: PubMed

ABSTRACT Transforming growth factor-beta (TGF-beta) has a pivotal function in the progression of renal fibrosis in a wide variety of renal diseases. Smad proteins have been identified to have an important function in regulating the expression of extracellular matrix (ECM) proteins through TGF-beta signaling pathway. Aberrant TGF-beta/Smad signaling can be modulated by stabilization of microtubules with paclitaxel. In this study, we investigated if paclitaxel can attenuate tubulointerstitial fibrosis in a rat model of unilateral ureteral obstruction (UUO). Rats in groups of six were subjected to UUO and received low-dose intraperitoneal injection of paclitaxel (0.3 mg/kg) twice a week. They were killed at day 7 and 14 after UUO or Sham operation. TGF-beta signaling cascade and status of various ECM proteins were evaluated by RT-PCR, western blotting and immunohistochemical or immunofluorescence staining. The paclitaxel treatment markedly suppressed Smad2 and Smad3 phosphorylation. This was associated with attenuated expression of integrin-linked kinase, collagens I and III, fibronectin (FN) and alpha-smooth muscle actin, and a substantial decrease in renal fibrosis in animals that underwent UUO and received paclitaxel. These data indicate that the low-dose paclitaxel ameliorates renal tubulointerstitial fibrosis by modulating TGF-beta signaling, and thus, the paclitaxel may have some therapeutic value in humans.

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    • "EMT is another important process affecting the population of interstitial fibroblasts which lose their epithelial phenotype and show the progressive development of a mesenchymal phenotype that leads to TEC damage and fibrosis in the kidney [11]. Many studies have demonstrated that TGF-í µí»½ promotes renal fibrosis through EMT by activation of Smad2/3 [12] [13] [14] and was counteracted with BMP-7 by motivation of Smad1/5/8 to maintain the epithelial phenotype of TECs [15] [16]. The expression of the mesenchymal phenotype in TECs and fibroblasts using S100A4 as a marker has been observed in many kidney diseases [17] [18]. "
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