TY - JOUR T1 - AMPK Attenuates Adriamycin-induced Oxidative Podocyte Injury through Thioredoxin-mediated Suppression of ASK1-P38 Signaling Pathway JF - Molecular Pharmacology JO - Mol Pharmacol DO - 10.1124/mol.113.089458 SP - mol.113.089458 AU - Kun Gao AU - Yuan Chi AU - Wei Sun AU - Masayuki Takeda AU - Jian Yao Y1 - 2013/12/30 UR - http://molpharm.aspetjournals.org/content/early/2013/12/30/mol.113.089458.abstract N2 - Oxidative stress-induced podocyte injury is one of the major mechanisms underlying the initiation and progression of glomerulosclerosis. AMPK, a serine/threonine kinase that senses intracellular energy status and maintains energy homeostasis, is reported to have anti-oxidative effects. However, little is known about its application and mechanism. In this study, we investigated whether and how AMPK affected oxidative podocyte injury induced by adriamycin (ADR). Exposure of podocytes to ADR resulted in cell injury, which was preceded by increased reactive oxygen species (ROS) generation and P38 activation. Prevention of oxidative stress with the antioxidant N-acetyl-cysteine and glutathione or inhibition of P38 with SB203580 attenuated cell injury. Activation of AMPK with three structurally different AMPK activators also protected podocytes from ADR-elicited cell injury. This effect was associated with strong suppression of oxidative stress-sensitive kinase ASK1 and P38 without obvious influence on ROS level. Further analyses revealed that AMPK promoted thioredoxin (Trx) binding to ASK1. Consistently, AMPK potently suppressed the expression of TXNIP, a negative regulator of Trx, whereas it significantly enhanced the activity of Trx reductases that convert oxidized Trx to reduced form. In further support of a key role of Trx, downregulation or inhibition of Trx exaggerated, whereas downregulation of TXNIP attenuated the cell injury. These results indicate that AMPK prevents oxidative cell injury through Trx-mediated suppression of ASK1-P38 signaling pathway. Our findings thus provide novel mechanistic insights into the antioxidative actions of AMPK. AMPK could be developed as a novel therapeutic target for treatment of oxidative cell injury. ER -