Impact of opiate-HIV-1 interactions on neurotoxic signaling
Kurt F Hauser1, Nazira El-Hage, Shreya Buch
1Department of Anatomy and Neurobiology, University of Kentucky College of Medicine, 800 Rose Street, Lexington, KY 40536-0298, USA. khauser@uky.edu
Abstract:
Opiate drug abuse exacerbates the pathogenesis of human immunodeficiency virus-1 (HIV-1) in the central nervous system through direct actions on glia and neurons. Opiate abuse causes widespread disruption of astroglial and microglial function, and significant increases in astroglial-derived proinflammatory cytokines and chemokines, which likely contributes to neuronal dysfunction, death, and HIV encephalitis. Neurons are also directly affected by opiate-HIV-1 interactions. HIV-1 and the viral proteins gp120 and Tat activate multiple caspase-dependent and caspase-independent proapoptotic pathways in neurons involving phosphatidylinositol 3-kinase (PI3 kinase)/Akt, as well as p38, c-Jun N-terminal kinase (JNK) and/or other mitogen-activated protein kinases (MAPKs). Opiates appear to decrease the threshold for HIV-1-mediated neurotoxicity by sending convergent signals that exacerbate proapoptotic events induced by viral and cellular toxic products. The synergistic proinflammatory and neurotoxic effects of opiate drugs on glia and neurons are largely mediated through mu opioid receptors, which are expressed by subpopulations of astroglia, microglia, and neurons. Opiate abuse intrinsically modifies the host response to HIV-1. Identification of how this occurs is providing considerable insight toward understanding the mechanisms underlying HIV-1-associated dementia.
Insights
Opiate abuse worsens human immunodeficiency virus-1 (HIV-1) central nervous system damage by harming glia and neurons. This interaction increases neuroinflammation and neuronal death, contributing to HIV-1-associated dementia.
Area of Science:
- Neuroscience
- Immunology
- Virology
Background:
- Opiate drug abuse significantly impacts the central nervous system (CNS) during human immunodeficiency virus-1 (HIV-1) infection.
- Opiate abuse disrupts glial cell function and increases pro-inflammatory cytokines, contributing to neuronal damage and HIV encephalitis.
Purpose of the Study:
- To investigate the synergistic neurotoxic and pro-inflammatory effects of opiate abuse and HIV-1 infection in the CNS.
- To elucidate the mechanisms by which opiates exacerbate HIV-1-mediated neurotoxicity.
Main Methods:
- The study examines the direct effects of opiates and HIV-1 proteins (gp120, Tat) on neuronal apoptosis.
- Analysis of signaling pathways including PI3 kinase/Akt and MAPKs (p38, JNK) involved in neurotoxicity.
- Investigation of the role of mu opioid receptors in mediating these effects.
Main Results:
- HIV-1 and its proteins activate caspase-dependent and -independent apoptotic pathways in neurons.
- Opiates lower the threshold for HIV-1-induced neurotoxicity by converging pro-apoptotic signals.
- Mu opioid receptors on glia and neurons mediate synergistic pro-inflammatory and neurotoxic effects.
Conclusions:
- Opiate abuse fundamentally alters the host response to HIV-1 in the CNS.
- Understanding these interactions provides critical insights into the mechanisms of HIV-1-associated dementia.
- Targeting mu opioid receptors may offer therapeutic strategies for mitigating neuroinflammation and neurodegeneration in HIV-1 patients with a history of opiate abuse.
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