title: miR-21 overexpression enhances TGF-β1-induced epithelial-to-mesenchymal transition by target smad7 and aggravates renal damage in diabetic nephropathy.
abstract: Epithelial-to-mesenchymal transition (EMT) plays an important role in renal interstitial fibrosis (RIF) with diabetic nephropathy (DN). Smad7 (a inhibitory smad), a downstream signaling molecules of TGF-β1, represses the EMT. The physiological function of miR-21 is closely linked to EMT and RIF. However, it remained unclear whether miR-21 over-expression affected TGF-β1-induced EMT by regulating smad7 in DN. In this study, real-time RT-PCR, cell transfection, luciferase reporter gene assays, western blot and confocal microscope were used, respectively. Here, we found that miR-21 expression was upregulated by TGF-β1 in time- and concentration -dependent manner. Moreover, miR-21 over-expression enhanced TGF-β1-induced EMT(upregulation of a-SMA and downregulation of E-cadherin) by directly down-regulating smad7/p-smad7 and indirectly up-regulating smad3/p-smad3, accompanied by the decrease of Ccr and the increase of col-IV, FN, the content of collagen fibers, RTBM, RTIAW and ACR. Meantime, the siRNA experiment showed that smad7 can directly regulate a-SMA and E-cadherin expression. More importantly, miR-21 inhibitor can not only inhibit EMT and fibrosis but also ameliorate renal structure and function. In conclusion, our results demonstrated that miR-21 overexpression can contribute to TGF-β1-induced EMT by inhibiting target smad7, and that targeting miR-21 may be a better alternative to directly suppress TGF-β1-mediated fibrosis in DN.
authors.affiliation: Metabolic Disease Center, School of Traditional Chinese Medicine, Capital Medical University, Beijing, China; Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China; Department of Endocrine and Metabolism, Capital Medical University, Beijing, China; Beijing Key Laboratory of Diabetes Research and Care, Beijing 100730, China.
authors.forename: Jin-Yang
authors.initials: JY
authors.lastname: Wang
authors.affiliation: Metabolic Disease Center, School of Traditional Chinese Medicine, Capital Medical University, Beijing, China; Department of Endocrine and Metabolism, Capital Medical University, Beijing, China. Electronic address: gaoyb111@hotmail.com.
authors.forename: Yan-Bin
authors.initials: YB
authors.lastname: Gao
authors.affiliation: Metabolic Disease Center, School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.
authors.forename: Na
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Metabolic Disease Center, School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Zou
authors.affiliation: Department of Neurobiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wang
authors.affiliation: Metabolic Disease Center, School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.
authors.forename: Zhi-Yao
authors.initials: ZY
authors.lastname: Zhu
authors.affiliation: Metabolic Disease Center, School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.
authors.forename: Jiao-Yang
authors.initials: JY
authors.lastname: Li
authors.affiliation: Metabolic Disease Center, School of Traditional Chinese Medicine, Capital Medical University, Beijing, China.
authors.forename: Sheng-Nan
authors.initials: SN
authors.lastname: Zhou
authors.affiliation: Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Shao-Cheng
authors.initials: SC
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Ying-Ying
authors.initials: YY
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Beijing Tongren Hospital, Capital Medical University, Beijing, China; Beijing Key Laboratory of Diabetes Research and Care, Beijing 100730, China. Electronic address: jinkui.yang@gmail.com.
authors.forename: Jin-Kui
authors.initials: JK
authors.lastname: Yang
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D015415:Biomarkers / Q000378:metabolism; D015820:Cadherins / Q000378:metabolism; D002460:Cell Line; D003928:Diabetic Nephropathies / Q000235:genetics / Q000473:pathology*; D015536:Down-Regulation / Q000187:drug effects; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D008297:Male; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010766:Phosphorylation / Q000187:drug effects; D051900:Smad3 Protein / Q000235:genetics / Q000378:metabolism; D051906:Smad7 Protein / Q000235:genetics / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C541116:ACTA2 protein, human; D000199:Actins; D015415:Biomarkers; D015820:Cadherins; C524940:MIRN21 microRNA, human; C531950:MIRN21 microRNA, mouse; D035683:MicroRNAs; C497806:SMAD7 protein, human; D051900:Smad3 Protein; D051906:Smad7 Protein; D053773:Transforming Growth Factor beta1
keywords: Diabetic nephropathy; Epithelial-to-mesenchymal transition; MicroRNA(miR); Renal interstitial fibrosis; TGF-β1