title: TGF-β1-elevated TRPM7 channel regulates collagen expression in hepatic stellate cells via TGF-β1/Smad pathway.
abstract: Transdifferentiation of hepatic stellate cells (HSCs) into myofibroblasts plays a critical role in the development of liver fibrosis, since myofibroblasts are the key cells responsible for excessive deposition of ECM proteins. Transient receptor potential melastatin 7 (TRPM7), a non-selective cation channel with protein serine/threonine kinase activity, has been demonstrated to function in the proliferation of activated HSCs. Here, we investigated the functional role of TRPM7 in collagen deposition in activated HSC-T6 cells (a rat hepatic stellate cell line). TRPM7 mRNA and protein were measured by Real-time PCR and Western blot in TGF-β1-activated HSC-T6 cells in vitro. Results demonstrated that TRPM7 protein was dramatically increased in fibrotic human livers. Stimulation of HSC-T6 cells with TGF-β1 increased TRPM7 mRNA and protein level in a time-dependent manner. Nevertheless, TGF-β1-elicited upregulation of TRPM7 in HSC-T6 cells was abrogated by SB431542 (TGF-β1 receptor blocker) or SIS3 (inhibitor of Smad3 phosphorylation). Additionally, blockade of TRPM7 channels with non-specific TRPM7 blocker 2-APB or synthetic siRNA targeting TRPM7 attenuated TGF-β1-induced expression of myofibroblast markers, as measured by the induction of α-SMA and Col1α1. Silencing TRPM7 also increased the ratio of MMPs/TIMPs by increasing MMP-13 expression and decreasing TIMP-1 and TIMP-2 levels. Strikingly, phosphorylation of p-Smad2 and p-Smad3, associated with collagen production, was decreased in TRPM7 deficient HSC-T6 cells. These observations suggested that TGF-β1 elevates TRPM7 expression in HSCs via Smad3-dependant mechanisms, which in turn contributes Smad protein phosphorylation, and subsequently increases fibrous collagen expression. Therefore, TRPM7 may constitute a useful target for the treatment of liver fibrosis.
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Institute for Liver Diseases of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Mei Shan Road, Hefei, Anhui Province 230032, China; The First Affiliated Hospital of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China. Electronic address: fangling_1984@126.com.
authors.forename: Ling
authors.initials: L
authors.lastname: Fang
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Institute for Liver Diseases of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Mei Shan Road, Hefei, Anhui Province 230032, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Huang
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Institute for Liver Diseases of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Mei Shan Road, Hefei, Anhui Province 230032, China.
authors.forename: Xiaoming
authors.initials: X
authors.lastname: Meng
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Institute for Liver Diseases of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Mei Shan Road, Hefei, Anhui Province 230032, China.
authors.forename: Baoming
authors.initials: B
authors.lastname: Wu
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Institute for Liver Diseases of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Mei Shan Road, Hefei, Anhui Province 230032, China.
authors.forename: Taotao
authors.initials: T
authors.lastname: Ma
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Institute for Liver Diseases of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Mei Shan Road, Hefei, Anhui Province 230032, China.
authors.forename: Xuejiao
authors.initials: X
authors.lastname: Liu
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Institute for Liver Diseases of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Mei Shan Road, Hefei, Anhui Province 230032, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhu
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Institute for Liver Diseases of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Mei Shan Road, Hefei, Anhui Province 230032, China; The First Affiliated Hospital of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China.
authors.forename: Shuxiang
authors.initials: S
authors.lastname: Zhan
authors.affiliation: School of Pharmacy, Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Institute for Liver Diseases of Anhui Medical University, Mei Shan Road, Hefei, Anhui Province 230032, China; Key Laboratory of Anti-inflammatory and Immune Medicine, Anhui Medical University, Ministry of Education, Mei Shan Road, Hefei, Anhui Province 230032, China. Electronic address: lj@ahmu.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
mesh_terms: D000199:Actins / Q000032:analysis; D000818:Animals; D003094:Collagen / Q000378:metabolism*; D024042:Collagen Type I / Q000032:analysis; D000090602:Collagen Type I, alpha 1 Chain; D055166:Hepatic Stellate Cells / Q000378:metabolism*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000502:physiology; D051785:Smad Proteins / Q000502:physiology*; D050053:TRPM Cation Channels / Q000032:analysis / Q000037:antagonists & inhibitors / Q000502:physiology*; D053773:Transforming Growth Factor beta1 / Q000502:physiology*
chemical_list: D000199:Actins; D003094:Collagen; D024042:Collagen Type I; D000090602:Collagen Type I, alpha 1 Chain; D051785:Smad Proteins; D050053:TRPM Cation Channels; D053773:Transforming Growth Factor beta1; C498862:Acta2 protein, rat; C486584:Trpm7 protein, rat
keywords: Col1α1; HSC; Liver fibrosis; Smad signaling; TGF-β1; TRPM7