HIV-1 infection of the central nervous system (CNS) occurs in a majority of AIDS patients, and cause neuron cell death and neurological dysfunction. The magnitude of neuronal dysfunction appears disproportionately large compared to the small number of HIV-1 infected macrophages/microglia, suggesting that indirect mechanisms are involved. Microglia/macrophages are the major target cells for HIV-1 infection in the CNS. Astrocytes occupy a large portion of the cerebral cortex, and are also susceptible to HIV-1 infection but to a restricted degree. Astrocyte apoptosis is induced by HIV-1 infection both in vitro and in vivo. While HIV-1 infection and pathogenesis is not yet understood in many systems, the process of HIV-1 infection of astrocytes is largely unknown. Our long-term objective is to identify mechanisms of HIV-1 infection and pathogenesis in the CNS that can be potentially served as therapeutic targets. The overall goal of this proposal is to determine the mechanisms of HIV-1 infection and pathogenesis in astrocytes. Recent studies from our laboratory demonstrated that HIV-1 infection of astrocytes is via a novel CD4-independent receptor 5C4R, and that direct binding of gp120 to 5C4R expressed on the cell surface induced 5C4R phosphorylation. Our studies also showed that astrocyte apoptosis induced by HIV-1 infection is a result of HIV-1 Nef expression in mitochondria. The underlying hypothesis for this proposal is that functional dysregulation of astrocytes by HIV-1 infection and interaction with HIV-1 viral protein gp120 and Nef results in, or contributes to HIV-1 neuropathogenesis. To test this hypothesis, we propose the following interrelated specific aims: 1) To characterize the newly-identified 5C4R receptor and its binding to gp120; 2) To determine mechanisms of 5C4R-mediated HIV-1 entry into astrocytes; 3) To characterize 5C4R-mediated signaling pathways in astrocytes upon gp120 binding; and 4) To determine mechanisms of Nef-induced apoptosis in 5C4R-mediated HIV-1 infection of astrocytes. Experimental approaches include the use of human fetal astrocyte cDNA expression cloning, 5C4R stable cell line, and an astroglial inducible cell line expressing HIV-1 Nef. These studies will yield insights that are fundamental to understanding the role of astrocytes in HIV-1 induced CNS pathology and will also elucidate the potential of HIV-1 Nef as targets for therapeutic intervention.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS039804-02
Application #
6394332
Study Section
Special Emphasis Panel (ZRG1-AARR-5 (01))
Program Officer
Nunn, Michael
Project Start
2000-04-01
Project End
2004-03-31
Budget Start
2001-04-01
Budget End
2002-03-31
Support Year
2
Fiscal Year
2001
Total Cost
$260,750
Indirect Cost
Name
Indiana University-Purdue University at Indianapolis
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
005436803
City
Indianapolis
State
IN
Country
United States
Zip Code
46202
Fan, Yan; Timani, Khalid Amine; He, Johnny J (2015) STAT3 and its phosphorylation are involved in HIV-1 Tat-induced transactivation of glial fibrillary acidic protein. Curr HIV Res 13:55-63
Fan, Yan; Zou, Wei; Green, Linden A et al. (2011) Activation of Egr-1 expression in astrocytes by HIV-1 Tat: new insights into astrocyte-mediated Tat neurotoxicity. J Neuroimmune Pharmacol 6:121-9
Zou, Wei; Wang, Zhenyuan; Liu, Ying et al. (2010) Involvement of p300 in constitutive and HIV-1 Tat-activated expression of glial fibrillary acidic protein in astrocytes. Glia 58:1640-8
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Green, Linden A; Liu, Ying; He, Johnny J (2009) Inhibition of HIV-1 infection and replication by enhancing viral incorporation of innate anti-HIV-1 protein A3G: a non-pathogenic Nef mutant-based anti-HIV strategy. J Biol Chem 284:13363-72
Henao-Mejia, Jorge; He, Johnny J (2009) Sam68 relocalization into stress granules in response to oxidative stress through complexing with TIA-1. Exp Cell Res 315:3381-95
Henao-Mejia, Jorge; Liu, Ying; Park, In-Woo et al. (2009) Suppression of HIV-1 Nef translation by Sam68 mutant-induced stress granules and nef mRNA sequestration. Mol Cell 33:87-96
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Lopez-Herrera, Albeiro; Liu, Ying; Rugeles, Maria T et al. (2005) HIV-1 interaction with human mannose receptor (hMR) induces production of matrix metalloproteinase 2 (MMP-2) through hMR-mediated intracellular signaling in astrocytes. Biochim Biophys Acta 1741:55-64
Zhang, Jizhong; Li, Geling; Bafica, Andre et al. (2005) Neisseria gonorrhoeae enhances infection of dendritic cells by HIV type 1. J Immunol 174:7995-8002

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