Mechanisms for Altered Glucose Homeostasis During HAART

描述（由申请人提供）：本项目的长期目标是了解在高效抗逆转录病毒治疗期间改变葡萄糖稳态的分子机制。本提案中的研究旨在确定导致β细胞功能受损和肝葡萄糖生成改变的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，所有目前可用的HIV蛋白酶抑制剂内的肽结构是负责急性和可逆的抑制胰岛素响应性葡萄糖转运蛋白GLUT 4和肝脏/胰腺转运蛋白GLUT 2。为了检验这一假设，将确定HIV蛋白酶抑制剂对新鲜分离的啮齿动物和人胰岛以及培养的MIN 6细胞中葡萄糖刺激的胰岛素分泌途径的急性作用。还将在大鼠中进行正常血糖高胰岛素钳夹实验，以确定HIV蛋白酶抑制剂对肝脏葡萄糖生成的急性影响。将在异源表达该转运蛋白同种型的爪蟾卵母细胞中检测双胍二甲双胍预防蛋白酶抑制剂介导的GLUT 4活性抑制的能力。最后，将通过测试合成芳香族肽家族抑制表达GLUT 4的卵母细胞中2-脱氧葡萄糖摄取的能力来确定PI诱导的GLUT 4抑制中涉及的结构决定因素。总之，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，保持其临床疗效，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.