1. Targeting BCAA Catabolism to Treat Obesity-Associated Insulin Resistance
- Author
-
Zhou, Meiyi, Shao, Jing, Wu, Cheng-Yang, Shu, Le, Dong, Weibing, Liu, Yunxia, Chen, Mengping, Wynn, R Max, Wang, Jiqiu, Wang, Ji, Gui, Wen-Jun, Qi, Xiangbing, Lusis, Aldons J, Li, Zhaoping, Wang, Weiqing, Ning, Guang, Yang, Xia, Chuang, David T, Wang, Yibin, and Sun, Haipeng
- Subjects
Obesity ,Brain Disorders ,Diabetes ,Nutrition ,2.1 Biological and endogenous factors ,Aetiology ,Development of treatments and therapeutic interventions ,5.1 Pharmaceuticals ,Metabolic and endocrine ,Stroke ,Oral and gastrointestinal ,Amino Acids ,Branched-Chain ,Animals ,Diet ,High-Fat ,Gene Expression ,Genome-Wide Association Study ,Glucose Tolerance Test ,Humans ,Insulin ,Insulin Resistance ,Male ,Mechanistic Target of Rapamycin Complex 1 ,Metabolome ,Mice ,Protein Kinases ,Signal Transduction ,Medical and Health Sciences ,Endocrinology & Metabolism - Abstract
Recent studies implicate a strong association between elevated plasma branched-chain amino acids (BCAAs) and insulin resistance (IR). However, a causal relationship and whether interrupted BCAA homeostasis can serve as a therapeutic target for diabetes remain to be established experimentally. In this study, unbiased integrative pathway analyses identified a unique genetic link between obesity-associated IR and BCAA catabolic gene expression at the pathway level in human and mouse populations. In genetically obese (ob/ob) mice, rate-limiting branched-chain α-keto acid (BCKA) dehydrogenase deficiency (i.e., BCAA and BCKA accumulation), a metabolic feature, accompanied the systemic suppression of BCAA catabolic genes. Restoring BCAA catabolic flux with a pharmacological inhibitor of BCKA dehydrogenase kinase (BCKDK) ( a suppressor of BCKA dehydrogenase) reduced the abundance of BCAA and BCKA and markedly attenuated IR in ob/ob mice. Similar outcomes were achieved by reducing protein (and thus BCAA) intake, whereas increasing BCAA intake did the opposite; this corroborates the pathogenic roles of BCAAs and BCKAs in IR in ob/ob mice. Like BCAAs, BCKAs also suppressed insulin signaling via activation of mammalian target of rapamycin complex 1. Finally, the small-molecule BCKDK inhibitor significantly attenuated IR in high-fat diet-induced obese mice. Collectively, these data demonstrate a pivotal causal role of a BCAA catabolic defect and elevated abundance of BCAAs and BCKAs in obesity-associated IR and provide proof-of-concept evidence for the therapeutic validity of manipulating BCAA metabolism for treating diabetes.
- Published
- 2019