Upregulation of mitochondrial Nox4 mediates TGF-beta-induced apoptosis in cultured mouse podocytes
- Authors
- Das, Ranjan; Xu, Shanhua; Quan, Xianglan; Tuyet Thi Nguyen; Kong, In Deok; Chung, Choon Hee; Lee, Eun Young; Cha, Seung-Kuy; Park, Kyu-Sang
- Issue Date
- Jan-2014
- Publisher
- American Physiological Society
- Keywords
- podocyte; transforming growth factor-beta; NADPH oxidase 4; mitochondria; apoptosis
- Citation
- American Journal of Physiology - Renal Physiology, v.306, no.2, pp F155 - F167
- Journal Title
- American Journal of Physiology - Renal Physiology
- Volume
- 306
- Number
- 2
- Start Page
- F155
- End Page
- F167
- URI
- https://scholarworks.bwise.kr/sch/handle/2021.sw.sch/12565
- DOI
- 10.1152/ajprenal.00438.2013
- ISSN
- 1931-857X
1522-1466
- Abstract
- Injury to podocytes leads to the onset of chronic renal diseases characterized by proteinuria. Elevated transforming growth factor (TGF)-beta in kidney tissue is associated with podocyte damage that ultimately results in apoptosis and detachment. We investigated the proapoptotic mechanism of TGF-beta in immortalized mouse podocytes. Exogenous TGF-beta(1)-induced podocyte apoptosis through caspase-3 activation, which was related to elevated ROS levels generated by selective upregulation of NADPH oxidase 4 (Nox4). In mouse podocytes, Nox4 was predominantly localized to mitochondria, and Nox4 upregulation by TGF-beta(1) markedly depolarized mitochondrial membrane potential. TGF-beta(1)-induced ROS production and caspase activation were mitigated by an antioxidant, the Nox inhibitor diphenyleneiodonium, or small interfering RNA for Nox4. A TGF-beta receptor I blocker, SB-431542, completely reversed the changes triggered by TGF-beta(1). Knockdown of either Smad2 or Smad3 prevented the increase of Nox4 expression, ROS generation, loss of mitochondrial membrane potential, and caspase-3 activation by TGF-beta(1). These results suggest that TGF-beta(1)-induced mitochondrial Nox4 upregulation via the TGF-beta receptor-Smad2/3 pathway is responsible for ROS production, mitochondrial dysfunction, and apoptosis, which may at least in part contribute to the development and progression of proteinuric glomerular diseases such as diabetic nephropathy.
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Collections - College of Medicine > Department of Internal Medicine > 1. Journal Articles
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