1. EGCG Attenuates Renal Damage via Reversing Klotho Hypermethylation in Diabetic db/db Mice and HK-2 Cells
- Author
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Xiao Meng Zhang, Bao Long Zhang, Li Li Guo, Jin Dong Tong, Hui Min Jin, Xiu Hong Yang, and Yan Hong Gu
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0301 basic medicine ,Aging ,Article Subject ,Cell Survival ,Kidney ,urologic and male genital diseases ,medicine.disease_cause ,Biochemistry ,DNA methyltransferase ,Catechin ,Cell Line ,Diabetes Mellitus, Experimental ,Transforming Growth Factor beta1 ,Superoxide dismutase ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Animals ,Humans ,DNA (Cytosine-5-)-Methyltransferases ,Promoter Regions, Genetic ,Klotho Proteins ,Klotho ,Glucuronidase ,QH573-671 ,biology ,Chemistry ,Kidney metabolism ,Cell Biology ,General Medicine ,Methylation ,DNA Methylation ,Molecular biology ,female genital diseases and pregnancy complications ,Mice, Inbred C57BL ,Oxidative Stress ,030104 developmental biology ,030220 oncology & carcinogenesis ,embryonic structures ,DNA methylation ,DNMT1 ,biology.protein ,Cytokines ,Inflammation Mediators ,Cytology ,Oxidative stress ,Research Article - Abstract
To explore whether epigallocatechin-3-gallate (EGCG) improves renal damage in diabetic db/db mice and high-glucose- (HG-) induced injury in HK-2 cells by regulating the level of Klotho gene promoter methylation. Western blotting was used to detect the protein expression levels of DNA methyltransferase 1 (DNMT1), DNMT3a, DNMT3b, transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA), and Klotho. The methylation level of the Klotho gene promoter was detected by pyrosequencing. Chromatin immunoprecipitation was used to detect the binding of the Klotho gene promoter to DNMT1 and DNMT3a. The expression of oxidative stress markers (reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), and 8-hydroxy-2′-deoxyguanosine (8-OHdG)) and inflammatory cytokines (interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α)) in kidney homogenates was also measured using ELISA. Klotho and DNMT3b protein expression was upregulated, while DNMT1, DNMT3a, TGF-β1, and α-SMA protein expression was downregulated after EGCG treatment. EGCG treatment also reduced the methylation level of the Klotho gene promoter as well as the binding of DNMT3a to the Klotho gene promoter. In addition, EGCG treatment significantly decreased the levels of ROS, MDA, 8-OHdG, IL-1β, IL-6, and TNF-α and increased the levels of CAT and SOD. Under HG conditions, EGCG regulated Klotho gene promoter methylation via DNMT3a and decreased the methylation level of the Klotho gene promoter, thereby upregulating the expression of the Klotho protein to exert its protective effect.
- Published
- 2020
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