Mechanisms for Altered Glucose Homeostasis During HAART

描述（由申请人提供）：该项目的长期目标是了解高活性抗逆转录病毒治疗期间葡萄糖稳态改变的分子机制。本研究旨在确定导致β细胞功能受损和肝脏葡萄糖生成改变的HIV蛋白酶抑制剂的细胞靶点，并阐明这种抑制的分子机制。我们假设，目前所有可用的HIV蛋白酶抑制剂中的肽结构都负责急性和可逆地抑制胰岛素反应性葡萄糖转运蛋白GLUT4和肝脏/胰腺转运蛋白GLUT2。为了验证这一假设，HIV蛋白酶抑制剂对新分离的啮齿动物和人胰岛以及培养的MIN6细胞中葡萄糖刺激的胰岛素分泌途径的急性影响将被确定。正糖高胰岛素钳夹实验也将在大鼠中进行，以确定HIV蛋白酶抑制剂对肝脏葡萄糖产生的急性影响。双胍类药物二甲双胍阻止蛋白酶抑制剂介导的GLUT4活性抑制的能力将在异种表达这种转运体亚型的非洲爪蟾卵细胞中进行测试。最后，参与pi诱导的GLUT4抑制的结构决定因素将通过测试一系列合成芳香肽来确定其抑制表达GLUT4的卵母细胞中2-脱氧葡萄糖摄取的能力。综上所述，这些研究将为HIV蛋白酶抑制剂治疗患者导致胰岛素抵抗的分子机制提供新的见解。这可能有助于设计新的HIV蛋白酶抑制剂，在保持其临床疗效的同时避免其对葡萄糖稳态的不良影响，并将有助于开发更有效的治疗策略。

DESCRIPTION (provided by applicant): The long-term objective of this project is to understand the molecular mechanisms responsible for altered glucose homeostasis during highly active antiretroviral therapy. The studies in this proposal are intended to identify the cellular targets of HIV protease inhibitors that lead to impaired beta-cell function and alterations in hepatic glucose production and to elucidate the molecular mechanism of this inhibition. We hypothesize that the peptide structure within all currently available HIV protease inhibitors is responsible for acute and reversible inhibition of the insulin-responsive glucose transporter GLUT4 and the liver/pancreas transporter GLUT2. To test this hypothesis, the acute effects of HIV protease inhibitors on the glucose-stimulated insulin secretory pathway in freshly isolated rodent and human islets as well as cultured MIN6 cells will be determined. Euglycemic hyperinsulinemic clamp experiments will also be performed in rats to determine the acute effects of HIV protease inhibitors on hepatic glucose production. The ability of the biguanide metformin to prevent protease inhibitor mediated inhibition of GLUT4 activity will be tested in Xenopus oocytes heterologously expressing this transporter isoform. Finally, the structural determinants involved in PI-induced GLUT4 inhibition will be determined by testing a family of synthetic aromatic peptides for their ability to inhibit 2-deoxyglucose uptake in GLUT4 expressing oocytes. Taken together, these studies will provide new insights into the molecular mechanism(s) leading to insulin resistance in patients treated with HIV protease inhibitors. This may facilitate the design of newer HIV protease inhibitors that maintain their clinical efficacy while avoiding their adverse effects on glucose homeostasis and will assist efforts to develop more effective treatment strategies.