1. Academic Validation
  2. Celastrol alleviates renal fibrosis by upregulating cannabinoid receptor 2 expression

Celastrol alleviates renal fibrosis by upregulating cannabinoid receptor 2 expression

  • Cell Death Dis. 2018 May 22;9(6):601. doi: 10.1038/s41419-018-0666-y.
Ming Tang 1 2 Xu Cao 1 Kun Zhang 1 You Li 1 Quan-You Zheng 1 Gui-Qing Li 2 Qian-Hui He 1 Shu-Jing Li 1 Gui-Lian Xu 3 Ke-Qin Zhang 4
Affiliations

Affiliations

  • 1 Department of Nephrology, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, 400038, China.
  • 2 Department of Immunology, Army Medical University (Third Military Medical University), Chongqing, 400038, China.
  • 3 Department of Immunology, Army Medical University (Third Military Medical University), Chongqing, 400038, China. [email protected].
  • 4 Department of Nephrology, Southwest Hospital, Army Medical University (Third Military Medical University), Chongqing, 400038, China. [email protected].
Abstract

Renal fibrosis is the final manifestation of various chronic kidney diseases, and no effective therapy is available to prevent or reverse it. Celastrol, a triterpene that derived from traditional Chinese medicine, is a known potent anti-fibrotic agent. However, the underlying mechanisms of action of celastrol on renal fibrosis remain unknown. In this study, we found that celastrol treatment remarkably attenuated unilateral ureteral obstruction (UUO)-induced mouse renal fibrosis. This was evidenced by the significant reduction in tubular injury; collagen deposition; accumulation of fibronectin, collagen I, and α-smooth muscle actin; and the expression levels of pro-fibrotic factors Vim, Cola1, and TGF-β1 mRNA, as well as inflammatory responses. Celastrol showed similar effects in a folic acid-induced mouse renal fibrosis model. Furthermore, celastrol potentiated the expression of the anti-fibrotic factor Cannabinoid Receptor 2 (CB2R) in established mouse fibrotic kidney tissues and transforming growth factor β1 (TGF-β1)-stimulated human kidney 2 (HK-2) cells. In addition, the CB2R antagonist (SR144528) abolished celastrol-mediated beneficial effects on renal fibrosis. Moreover, UUO- or TGF-β1-induced activation of the pro-fibrotic factor Smad Family member 3 (SMAD3) was markedly inhibited by celastrol. Inhibition of SMAD3 activation by an inhibitor (SIS3) markedly reduced TGF-β1-induced downregulation of CB2R expression. In conclusion, our study provides the first direct evidence that celastrol significantly alleviated renal fibrosis, by contributing to the upregulation of CB2R expression through inhibiting SMAD3 signaling pathway activation. Therefore, celastrol could be a potential drug for treating patients with renal fibrosis.

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