METABOLISM. S-Nitrosylation links obesity-associated inflammation to endoplasmic reticulum dysfunction.

ABSTRACT: The association between inflammation and endoplasmic reticulum (ER) stress has been observed in many diseases. However, if and how chronic inflammation regulates the unfolded protein response (UPR) and alters ER homeostasis in general, or in the context of chronic disease, remains unknown. Here, we show that, in the setting of obesity, inflammatory input through increased inducible nitric oxide synthase (iNOS) activity causes S-nitrosylation of a key UPR regulator, IRE1?, which leads to a progressive decline in hepatic IRE1?-mediated XBP1 splicing activity in both genetic (ob/ob) and dietary (high-fat diet-induced) models of obesity. Finally, in obese mice with liver-specific IRE1? deficiency, reconstitution of IRE1? expression with a nitrosylation-resistant variant restored IRE1?-mediated XBP1 splicing and improved glucose homeostasis in vivo. Taken together, these data describe a mechanism by which inflammatory pathways compromise UPR function through iNOS-mediated S-nitrosylation of IRE1?, which contributes to defective IRE1? activity, impaired ER function, and prolonged ER stress in obesity.

SUBMITTER: Yang L 

PROVIDER: S-EPMC4573582 | biostudies-literature | 2015 Jul

REPOSITORIES: biostudies-literature