The long term goal of this project is to understand the molecular mechanisms responsible for altered glucose homeostasis during highly active antiretroviral therapy (HAART). The metabolic changes that occur in association with the use of HIV protease inhibitors (Pis) have significant potential for increasing cardiac- associated morbidity and mortality. The immediate objectives of this proposal are to determine the specific contribution of GLUT4 inhibition to altered glucose uptake into insulin responsive tissues, to elucidate the role of altered glucose transport in the development of changes in adiocytokine production, and to identify the precise molecular interactions that mediate PI binding to GLUT4. The role of GLUT4 in Pi-induced effects on peripheral glucose disposal will be studied by measuring radiolabeled 2-deoxyglucose uptake into cardiac, skeletal muscle and adipose tissue under basal and hyperinsulinemic euglycemic clamp conditions in wild-type and transgenic mice with specific deletion of GLUT4 from muscle or fat. Changes in leptin, adiponectin and resistin RNA and protein levels, peripheral glucose disposal, and hepatic glucose production will be determined following semi-acute exposure of control and GLUT4 null mice to Pis in the presence and absence of semi-chronic treatment with NRTIs. The structural features in GLUT4 that mediate HIV protease inhibitor binding and inactivation will be determined in primary and/or cultured rat adipocytes labeled with a photoactivatable peptide containing the GLUT4 inhibiting epitope zHFF coupled to the FLAG epitope. Modified proteins will be isolated using a FLAG antibody affinity column and identified by mass spectrometry. The ability of Pis to influence the binding of proteins known to interact with the GLUT4 carboxy terminus will also be investigated by Western blot analysis and co-immunoprecipitation experiments using factor specific antibodies. Mutations will be introduced into the identified GLUT4 PI binding site and the resulting functional effects on transport activity and PI sensitivity will be determined. Taken together, these studies will provide crucial information about the mechanism(s) by which Pis contribute to the development of insulin resistance and diabetes mellitus. This will greatly assist efforts to develop effective strategies for preventing and/or treating the metabolic changes that occur both in patients on HAART and in the wider context of HIV-negative individuals with features of the metabolic syndrome.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK064572-08
Application #
7764755
Study Section
AIDS Clinical Studies and Epidemiology Study Section (ACE)
Program Officer
Pawlyk, Aaron
Project Start
2003-04-01
Project End
2012-01-31
Budget Start
2010-02-01
Budget End
2012-01-31
Support Year
8
Fiscal Year
2010
Total Cost
$294,941
Indirect Cost
Name
Washington University
Department
Pediatrics
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
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Aerni-Flessner, Lauren; Abi-Jaoude, Melissa; Koenig, Amanda et al. (2012) GLUT4, GLUT1, and GLUT8 are the dominant GLUT transcripts expressed in the murine left ventricle. Cardiovasc Diabetol 11:63
Vyas, Arpita Kalla; Aerni-Flessner, Lauren B; Payne, Maria A et al. (2012) Saxagliptin Improves Glucose Tolerance but not Survival in a Murine Model of Dilated Cardiomyopathy. Cardiovasc Endocrinol 1:74-82
Hruz, Paul W (2011) Molecular mechanisms for insulin resistance in treated HIV-infection. Best Pract Res Clin Endocrinol Metab 25:459-68
Remedi, Maria Sara; Agapova, Sophia E; Vyas, Arpita K et al. (2011) Acute sulfonylurea therapy at disease onset can cause permanent remission of KATP-induced diabetes. Diabetes 60:2515-22
Vyas, Arpita Kalla; Yang, Kai-Chien; Woo, Dennis et al. (2011) Exenatide improves glucose homeostasis and prolongs survival in a murine model of dilated cardiomyopathy. PLoS One 6:e17178
Hruz, Paul W; Yan, Qingyun; Tsai, Luong et al. (2011) GS-8374, a novel HIV protease inhibitor, does not alter glucose homeostasis in cultured adipocytes or in a healthy-rodent model system. Antimicrob Agents Chemother 55:1377-82
Hresko, Richard C; Hruz, Paul W (2011) HIV protease inhibitors act as competitive inhibitors of the cytoplasmic glucose binding site of GLUTs with differing affinities for GLUT1 and GLUT4. PLoS One 6:e25237
Vyas, Arpita Kalla; Koster, Joseph C; Tzekov, Anatoly et al. (2010) Effects of the HIV protease inhibitor ritonavir on GLUT4 knock-out mice. J Biol Chem 285:36395-400
Tu, Powen; Bhasin, Shalender; Hruz, Paul W et al. (2009) Genetic disruption of myostatin reduces the development of proatherogenic dyslipidemia and atherogenic lesions in Ldlr null mice. Diabetes 58:1739-48

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