Drug abuse and HIV/AIDS are interlinked epidemics because of increased spread of HIV-1 through needle sharing and through the exchange of sex for drugs. During the past decade, we have proposed that, besides peripheral immune dysregulation, opiates exacerbate the pathological effects of HIV in the CNS though direct actions on ?-opioid receptor expressing (MOR) neurons and glia. The CNS may be preferentially vulnerable to opiate and HIV-1 interactions because of the complexity and interrelatedness of MOR action in neurons, astroglia, microglia and endothelium. We recently reported that convergent, neurotoxic effects of Tat or gp120 and morphine are largely due to actions of MOR+ glia. Our in vivo work supports a central role for glia in sublethal/lethal synaptodendritic injury. Morphine worsens structural and functional irregularities in hippocampus and striatum of Tat-expressing mice, including spine losses and synaptodendritic injury. Neurotoxic interactions with morphine and gp120 are HIV strain specific. Medium from monocytes exposed to live or UV-inactivated R5-tropic HIV-1SF162 virions is toxic to neurons;this is significantly attenuated by the CCR5 antagonist maraviroc. We hypothesize that opiate-induced exacerbation of HIV toxicity is regulated through differential CCR5 signaling between microglia, astroglia, and neurons, which can injure or protect neurons depending on context. We propose that opiates and Tat or HIV interact downstream of TNF? to enhance inflammatory chemokine release from astroglia. In particular, convergent effects of opiates and Tat/HIV appear to dysregulate CCL5/CCR5 signaling, creating a milieu that promotes microglial motility and spiraling microglial activation. Our hypotheses are tested in 3 aims that examine individual roles of astroglia and microglia in driving neurotoxic opiate-HIV interactions.
Aims 1 &2 use murine models for both: a) long-term, repeated imaging of cell death and sublethal neurodegenerative changes;and b) in vivo studies to detect population changes, neuron pathology, and behavioral deficits. Models include mice with cell-specific Cre-lox ablation of MOR, and inducible Tat transgenic mice crossed with CCL5-/- or CCR-/- mice.
In Aim 3, human glia and neurons are used to study neurodegenerative changes due to HIV and opiate effects related to CCL5- CCR5 signaling in an infectious model with multiple strains of HIV. Infectious/non-infectious effects of CCR5 activation are sorted using live and inactivated virus, and mutant viral strains. The CCR5 pathway is especially relevant to HIV. CCR5 is an HIV co-receptor for M-tropic strains;CCR5 polymorphisms affect disease susceptibility;the CCR5 antagonist maraviroc slows HIV progression clinically. Studies are essential for informing therapeutic strategies. By defining how each glial type contributes to CCL5/CCR5 dysregulation, judicious cell- and pathway-specific measures to prevent the neurotoxic sequelae of opiate-HIV co-exposure can be designed.

Public Health Relevance

HIV infection and injection drug use are interlinked epidemics with devastating consequences for public health. Opioid drug abuse appears to enhance CNS deficits that occur due to HIV-1 infection. Our previous work showed that glia are critical mediators of combined neurotoxic effects of opiates and HIV proteins. This project examines the respective roles of astroglia and microglia in orchestrating synergistic neurotoxicity. We propose that CCL5-CCR5 signaling is disrupted by opiate-HIV interactions in complex systems. Upregulation of CCL5 release from astroglia, and enhanced activation of microglia via CCR5, drives a cascade of events that enhances synaptodendritic injury, and that may be reversible. Identifying the cellular source of opiate-HIV synergy and the key intercellular signals will be a critical step towards interrupting neurotoxic events.

National Institute of Health (NIH)
National Institute on Drug Abuse (NIDA)
Research Project (R01)
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Special Emphasis Panel (ZRG1-AARR-C (02))
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Sorensen, Roger
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Virginia Commonwealth University
Anatomy/Cell Biology
Schools of Medicine
United States
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Kim, Sarah; Hahn, Yun Kyung; Podhaizer, Elizabeth M et al. (2018) A central role for glial CCR5 in directing the neuropathological interactions of HIV-1 Tat and opiates. J Neuroinflammation 15:285
Wodarski, Rachel; Bagdas, Deniz; Paris, Jason J et al. (2018) Reduced intraepidermal nerve fibre density, glial activation, and sensory changes in HIV type-1 Tat-expressing female mice: involvement of Tat during early stages of HIV-associated painful sensory neuropathy. Pain Rep 3:e654
Gonek, Maciej; McLane, Virginia D; Stevens, David L et al. (2018) CCR5 mediates HIV-1 Tat-induced neuroinflammation and influences morphine tolerance, dependence, and reward. Brain Behav Immun 69:124-138
Leibrand, Crystal R; Paris, Jason J; Ghandour, M Said et al. (2017) HIV-1 Tat disrupts blood-brain barrier integrity and increases phagocytic perivascular macrophages and microglia in the dorsal striatum of transgenic mice. Neurosci Lett 640:136-143
Schier, Christina J; Marks, William D; Paris, Jason J et al. (2017) Selective Vulnerability of Striatal D2 versus D1 Dopamine Receptor-Expressing Medium Spiny Neurons in HIV-1 Tat Transgenic Male Mice. J Neurosci 37:5758-5769
Poland, Ryan S; Hahn, Yun; Knapp, Pamela E et al. (2016) Ibudilast attenuates expression of behavioral sensitization to cocaine in male and female rats. Neuropharmacology 109:281-292
Marks, William D; Paris, Jason J; Schier, Christina J et al. (2016) HIV-1 Tat causes cognitive deficits and selective loss of parvalbumin, somatostatin, and neuronal nitric oxide synthase expressing hippocampal CA1 interneuron subpopulations. J Neurovirol 22:747-762
Arnatt, Christopher K; Falls, Bethany A; Yuan, Yunyun et al. (2016) Exploration of bivalent ligands targeting putative mu opioid receptor and chemokine receptor CCR5 dimerization. Bioorg Med Chem 24:5969-5987
Fitting, Sylvia; Stevens, David L; Khan, Fayez A et al. (2016) Morphine Tolerance and Physical Dependence Are Altered in Conditional HIV-1 Tat Transgenic Mice. J Pharmacol Exp Ther 356:96-105
Hahn, Yun K; Paris, Jason J; Lichtman, Aron H et al. (2016) Central HIV-1 Tat exposure elevates anxiety and fear conditioned responses of male mice concurrent with altered mu-opioid receptor-mediated G-protein activation and ?-arrestin 2 activity in the forebrain. Neurobiol Dis 92:124-36

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