title: Astragaloside IV inhibits renal tubulointerstitial fibrosis by blocking TGF-β/Smad signaling pathway in vivo and in vitro.
abstract: Astragaloside IV (AS-IV) is a major active ingredient from Radix astragali, which has been considered as a renoprotective agent; however, its molecular mechanisms are unclear. Thus, we designed to investigate the renoprotective effects and mechanisms of AS-IV in rat model of renal fibrosis induced by unilateral ureteral obstruction (UUO) in vivo and TGF-β1-stimulated rat renal fibroblasts (NRK-49F) in vitro. Sprague-Dawley rats were randomly divided into six groups: sham operation, UUO, UUO/AS-IV (3.3, 10, 33 mg·kg(-1)·d(-1)), and UUO/enalapril (4 mg·kg(-1)·d(-1)). Renal function, tubulointerstitial damage index score, extracellular matrix (ECM) deposition, and the expressions of TGF-β1, connective tissue growth factor (CTGF), α-SMA, fibronectin, collagen I, III, Smad2/3, phosphorylated-Smad2/3, and Smad7 were measured. In addition, the expressions of CTGF, α-SMA, fibronectin, collagen I, III, Smad2/3, phosphorylated-Smad2/3, and Smad7 were measured in TGF-β1-stiumlated NRK-49F cell line. AS-IV significantly decreased UUO-induced renal fibrosis and functional impairment, which are associated with inhibition of TGF-β1, CTGF, α-SMA, and collagen matrix expression, and a decrease in serum creatinine and urea nitrogen. The renoprotective effects of AS-IV on fibrosis were associated with up-regulation of Smad7, thereby blocking up-regulations of TGF-β1, CTGF, and α-SMA, and activation of phosphorylated-Smad2/3. These effects were further conformed in NRK-49F cell line stimulated by TGF-β1. Moreover, knockdown of Smad7 gene in NRK-49F cells was able to prevent AS-IV-induced inhibition to Smad2/3 signaling activation, expression of CTGF, α-SMA, and ECM proteins in response to TGF-β1. Renal tubulointerstitial fibrosis was attenuated by treatment with AS-IV, which was closely related to induction of Smad7, thereby inhibiting TGF-β/Smad signaling.
authors.affiliation: Laboratory of Renal Disease, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Nephrology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China.
authors.forename: Yang-Feng
authors.initials: YF
authors.lastname: Chi
authors.affiliation: Experimental Research Center, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China.
authors.forename: Ze-Ting
authors.initials: ZT
authors.lastname: Yuan
authors.affiliation: Laboratory of Renal Disease, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China.
authors.forename: Wen-Chao
authors.initials: WC
authors.lastname: Zhou
authors.affiliation: Department of Nephrology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China.
authors.forename: Pei-Hao
authors.initials: PH
authors.lastname: Yin
authors.affiliation: Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203, China xuemzhang@fudan.edu.cn.
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Zhang
authors.affiliation: Laboratory of Renal Disease, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China Department of Nephrology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China pengwen_01@vip.sina.com.
authors.forename: Wen
authors.initials: W
authors.lastname: Peng
authors.affiliation: Renal Division, Department of Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA Section of Nephrology, Atlanta Veterans Administration Medical Center, Decatur, GA 30322, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005355:Fibrosis / Q000473:pathology / Q000517:prevention & control*; D020869:Gene Expression Profiling; D007668:Kidney / Q000187:drug effects* / Q000473:pathology; D007674:Kidney Diseases / Q000473:pathology / Q000517:prevention & control*; D007677:Kidney Function Tests; D017207:Rats, Sprague-Dawley; D012503:Saponins / Q000008:administration & dosage*; D012720:Severity of Illness Index; D015398:Signal Transduction / Q000187:drug effects*; D051906:Smad7 Protein / Q000096:biosynthesis*; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors*; D014315:Triterpenes / Q000008:administration & dosage*
chemical_list: D012503:Saponins; D051906:Smad7 Protein; C497808:Smad7 protein, rat; D016212:Transforming Growth Factor beta; D014315:Triterpenes; C052064:astragaloside A
keywords: Astragaloside IV; TGF-β/Smad signaling pathway; renal tubulointerstitial fibrosis; unilateral ureteral obstruction