Mitochondria-targeted Antioxidants Protect Pancreatic β-cells against Oxidative Stress and Improve Insulin Secretion in Glucotoxicity and Glucolipotoxicity.

Lim, Sangbin; Rashid, Md Abdur; Jang, Miran; Kim, Yeonghwan; Won, Hyeran; Lee, Jeonghoon; Woo, Jeong-taek; Kim, Young Seol; Murphy, Michael P.; Ali, Liaquat; Ha, Joohun; Kim, Sung Soo

Mitochondrial oxidative damage is thought to play a key role in pancreatic β-cell failure in the pathogenesis of type 2 diabetes. Despite this, the potential of mitochondria-targeted antioxidants to protect pancreatic β-cells against oxidative stress has not yet been studied. Therefore, we investigated if mitochondria-targeted antioxidants protect pancreatic β-cells such as RINm5F and HIT-T15 cells against oxidative stress under glucotoxic and glucolipotoxic conditions. When β-cells were incubated under these conditions, the expression levels of mitochondrial electron transport chain complex subunits, mitochondrial antioxidant enzymes (such as MnSOD and Prx3), β-cell apoptosis, lipogenic enzymes (such as ACC, FAS and ABCA1), intracellular lipid accumulation, oxidative stress, ER stress, mitochondrial membrane depolarization, nuclear NF- κB and sterol regulatory element binding protein 1c (SREBP1c) were all increased, in parallel with decreases in intracellular ATP content, citrate synthase enzymatic activity and glucose-stimulated insulin secretion. These changes were consistent with elevated mitochondrial oxidative stress, and incubation with the mitochondria-targeted antioxidants, MitoTempol or Mitoquinone (MitoQ), prevented these effects. In conclusion, mitochondria-targeted antioxidants protect pancreatic β-cells against oxidative stress, promote their survival, and increase insulin secretion in cell models of the glucotoxicity and glucolipotoxicity associated with Type 2 diabetes. Copyright © 2011 S. Karger AG, Basel

ANTIOXIDANTS; OXIDATIVE stress; PANCREATIC beta cells; BLOOD sugar; DIABETES; ELECTRON transport; CARRIER proteins

Cellular Physiology & Biochemistry (Karger AG), 2011, Vol 28, Issue 5, p873

1015-8987

Academic Journal

10.1159/000335802