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Abstract: TH-PO671

The Effect of GSTK1 on the MAM Related Apoptosis in Diabetic Nephropathy

Session Information

Category: Diabetes

  • 501 Diabetes Mellitus and Obesity: Basic - Experimental

Authors

  • Zhao, Li, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Hu, Chun, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Chen, Xianghui, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Han, Yachun, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Xiong, Xiaofen, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Li, Li, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Yang, Ming, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Gao, Peng, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Xiao, Li, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Li, Jun, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Liu, Fuyou, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
  • Sun, Lin, 2nd Xiangya Hospital, Central South University, Changsha, Hunan, China
Background

Mitochondria-associated ER Membrane (MAM)is a platform between mitochondria and ER,which involved in mitochondrial dynamic, calcium signaling,autophagy,apoptosis and so on. GSTK1 has glutathione peroxidase activity, which as an important antioxidant enzyme can blocking ROS damage. We found by first time GSTK1 locates on MAM of the mouse kidney ,but its function in MAM is nuclear.Here we hypothesize that GSTK1 in MAM modulates cell apoptosis may paly an important role in the kidney damagy of DN.

Methods

Morphological change of MAM was measured by EM in db/db and db/m mice. The protein of mitochondria, MAM and ER were extracted from the kdieny of diabetic mouse. The expression of GSTK1, Mfn-2, cytochrome C, caspase-3 and Bax were measured by Western blot analyse. In vitro study: MAM morphology was detected by confocal scanning in HK-2 cells. The mitochondria and MAM were also isolated from HK-2 cells induced by high glucose transfection with or without GSTK1 plasmid. The expression and distribution of GSTK1,Mfn-2,cytochrome C and Bax in MAM were detected by Western blot. Further, the interaction between GSTK1 and cytochrome C was observed by physical conformation, Confocal scanning and co-immunoprecipitation.

Results

Compared with db/m mice, the morphology of MAM was abnormal with the distance widen in the kidney of db/db mice. The expression of GSTK1 and Mfn-2 in mitochondria and MAM subdomain were down-regulated in db/db mices kidney. Conversely, the expression of Bax, Caspase-3 and cytochrome C were up-regulated. In addition, mitochondria was less adjacent to ER in HK-2 cells treated with high glucose(HG),while the expression of Mfn-2 was increased in mitochondria and MAM. all of altered were reversed in that transfection of GSTK1. Furthermore, a increased GSTK1 binding to cytochrome C was obsvered in HK-2 cells treated by HG. Overexpression of GSTK1 in HK-2 cells inhibited the release of mito.cytochrome C into the cytosol and Bax translocation to mitochondria, and reduced mitochondria modulate cells apoptosis.

Conclusion

The integrity of MAM were damaged and the distance between mitochondria and ER was increased in diabetic kidney or HG induced HK-2 cells. Overexpression of GSTK1 up-regulated the expression of Mfn-2 and then enhanced the interaction of MAM, which could inhibits apoptosis in DN.

Funding

  • Government Support - Non-U.S.