title: TGFβ-incurred epigenetic aberrations of miRNA and DNA methyltransferase suppress Klotho and potentiate renal fibrosis.
abstract: Renal fibrosis is a common pathological feature of chronic kidney diseases (CKD) and its development and progression are significantly affected by epigenetic modifications such as aberrant miRNA and DNA methylation. Klotho is an anti-aging and anti-fibrotic protein and its early decline after renal injury is reportedly associated with aberrant DNA methylation. However, the key upstream pathological mediators and the molecular cascade leading to epigenetic Klotho suppression are not exclusively established. Here we investigate the epigenetic mechanism of Klotho deficiency and its functional relevance in renal fibrogenesis. Fibrotic kidneys induced by unilateral ureteral occlusion (UUO) displayed marked Klotho suppression and the promoter hypermethylation. These abnormalities were likely due to deregulated transforming growth factor-beta (TGFβ) since TGFβ alone caused the similar epigenetic aberrations in cultured renal cells and TGFβ blockade prevented the alterations in UUO kidney. Further investigation revealed that TGFβ enhanced DNA methyltransferase (DNMT) 1 and DNMT3a via inhibiting miR-152 and miR-30a in both renal cells and fibrotic kidneys. Accordingly the blockade of either TGFβ signaling or DNMT1/3a activities significantly recovered the Klotho loss and attenuated pro-fibrotic protein expression and renal fibrosis. Moreover, Klotho knockdown by RNA interferences abolished the anti-fibrotic effects of DNMT inhibition in both TGFβ-treated renal cell and UUO kidney, indicating that TGFβ-mediated miR-152/30a inhibitions, DNMT1/3a aberrations and subsequent Klotho loss constitute a critical regulatory loop that eliminates Klotho's anti-fibrotic activities and potentiates renal fibrogenesis. Thus, our study elaborates a novel epigenetic cascade of renal fibrogenesis and reveals the potential therapeutic targets for treating the renal fibrosis-associated kidney diseases.
authors.affiliation: Nanjing University School of Medicine, Jiangsu, Key Laboratory of Molecular Medicine, Nanjing 210093, China.
authors.forename: Shasha
authors.initials: S
authors.lastname: Yin
authors.affiliation: Nanjing University School of Medicine, Jiangsu, Key Laboratory of Molecular Medicine, Nanjing 210093, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Nanjing University School of Medicine, Jiangsu, Key Laboratory of Molecular Medicine, Nanjing 210093, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Nanjing University School of Medicine, Jiangsu, Key Laboratory of Molecular Medicine, Nanjing 210093, China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Lin
authors.affiliation: Nanjing University School of Medicine, Jiangsu, Key Laboratory of Molecular Medicine, Nanjing 210093, China.
authors.forename: Yanning
authors.initials: Y
authors.lastname: Li
authors.affiliation: Nanjing University School of Medicine, Jiangsu, Key Laboratory of Molecular Medicine, Nanjing 210093, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Chen
authors.affiliation: Nanjing University School of Medicine, Jiangsu, Key Laboratory of Molecular Medicine, Nanjing 210093, China. Electronic address: wangsencao@nju.edu.cn.
authors.forename: Wangsen
authors.initials: W
authors.lastname: Cao
mesh_terms: D000818:Animals; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism; D019175:DNA Methylation; D000090205:DNA Methyltransferase 3A; D004791:Enzyme Inhibitors / Q000494:pharmacology; D044127:Epigenesis, Genetic; D005355:Fibrosis; D005966:Glucuronidase / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D000090265:Klotho Proteins; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D051436:Renal Insufficiency, Chronic / Q000378:metabolism* / Q000473:pathology; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000494:pharmacology*
chemical_list: C000717967:DNMT3A protein, human; C000715535:Dnmt3a protein, mouse; D004791:Enzyme Inhibitors; C550857:MIRN152 microRNA, mouse; D035683:MicroRNAs; C534715:Mirn30d microRNA, mouse; D016212:Transforming Growth Factor beta; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; D000090205:DNA Methyltransferase 3A; C000619380:DNMT1 protein, human; C000619381:Dnmt1 protein, mouse; D005966:Glucuronidase; D000090265:Klotho Proteins
keywords: DNA methylation; Klotho; Renal fibrosis; TGFβ; miRNA