Mitochondrial uncoupling protein-2 deficiency protects steatotic mouse hepatocytes from hypoxia/reoxygenation

作者：Evans Zachary P; Palanisamy Arun P; Sutter Alton G; Ellett Justin D; Ramshesh Venkat K; Attaway Hubert; Schmidt Michael G; Schnellmann Rick G; Chavin Kenneth D^*

来源：American Journal of Physiology - Gastrointestinal and Liver Physiology, 2012, 302(3): G336-G342.

DOI：10.1152/ajpgi.00049.2011

• liver
• mitochondria
• steatosis

Evans ZP, Palanisamy AP, Sutter AG, Ellett JD, Ramshesh VK, Attaway H, Schmidt MG, Schnellmann RG, Chavin KD. Mitochondrial uncoupling protein-2 deficiency protects steatotic mouse hepatocytes from hypoxia/reoxygenation. Am J Physiol Gastrointest Liver Physiol 302: G336-G342, 2012. First published November 17, 2011; doi:10.1152/ajpgi.00049.2011.-Steatotic livers are sensitive to ischemic events and associated ATP depletion. Hepatocellular necrosis following these events may result from mitochondrial uncoupling protein-2 (UCP2) expression. To test this hypothesis, we developed a model of in vitro steatosis using primary hepatocytes from wild-type (WT) and UCP2 knockout (KO) mice and subjected them to hypoxia/reoxygenation (H/R). Using cultured hepatocytes treated with emulsified fatty acids for 24 h, generating a steatotic phenotype (i.e., microvesicular and broad-spectrum fatty acid accumulation), we found that the phenotype of the WT and UCP2 KO were the same; however, cellular viability was increased in the steatotic KO hepatocytes following 4 h of hypoxia and 24 h of reoxygenation; Hepatocellular ATP levels decreased during hypoxia and recovered after reoxygenation in the control and UCP2 KO steatotic hepatocytes but not in the WT steatotic hepatocytes; mitochondrial membrane potential in WT and UCP2 KO steatotic groups was less than control groups but higher than UCP2 KO hepatocytes. Following reoxygenation, lipid peroxidation, as measured by thiobarbituric acid reactive substances, increased in all groups but to a greater extent in the steatotic hepatocytes, regardless of UCP2 expression. These results demonstrate that UCP2 sensitizes steatotic hepatocytes to H/R through mitochondrial depolarization and ATP depletion but not lipid peroxidation.

• 出版日期2012-2