Inter- and Intra-cellular effects of cannabinoids, HIV and ART in the CNS

Abstract: Antiretroviral therapy (ART) has dramatically extended the lives of people living with HIV (PLWH); however, they continue to experience a plethora of co-morbid conditions including neuronal disorders and pain. Between 40 and 72% of PLWH use cannabis to mitigate anxiety, stress, ART side effects, pain, and/or for pleasure with over 55% of patients using cannabis at least daily. Interestingly, a recent study found that people who use cannabis heavily had reduced inflammatory signatures in PLWH on ART. These and a numerous other studies support the anti-inflammatory and immunomodulator effects of phytocannabinoids in a number of organ systems including heart, colon, kidney, liver and the gut; however, their medicinal use is confounded by the psychotropic activities. Efforts to separate the anti-inflammatory effects from the psychotropic effects have revealed differential activities of 3 endogenous receptors including cannabis receptor 1 (CB2) CB2 which exhibit differential tissue expression and agonism with endo- and phyto-cannabinoids. Several reports have shown that cannabinoids attenuate HIV infection and/or replication in T-cells, macrophages, dendritic cells and human fetal microglia cultured ex vivo. However, the effect of cannabinoids on HIV infection of microglia in the context of ART and the normal cellular environment of neighboring neurons and astrocytes in the CNS has not been examined. Several studies specifically implicate CB2 agonism which has been shown to have anti- inflammatory properties in the heart, gut, experimental autoimmune encephalitis and neuropathic pain via inflammasome activation. This has led us to hypothesize that Cannabinoid signaling influences HIV infection and chronic inflammation in the presence of ARV in the central nervous system by attenuating the inflammasome. In order to examine HIV infection in the context of cells of the CNS, we have developed a human induced pluripotent stem cell tri-culture model composed of iNeurons, iAstrocytes, and iMicroglia. This model recapitulates several key aspects of HIV infection in the CNS including increased cytokine production, oxidative stress response, inflammatory signaling, and integrated stress response. ARV treatment reduces HIV infection and inflammatory signaling pathways; however, a subset of pathways remain elevated despite viral suppression. We propose to further develop this model to determine the ability of cannabinoids to modulate HIV-induced inflammation and subsequent neuronal dysfunction via reducing inflammasome activation by: 1) Determining the effect of cannabinoids on chronic HIV infection and ART in the context of iMgl/iNrn/iAstr triculture. 2) Determining the effect of cannabinoids on cytokine levels, inflammatory gene expression profile, and microglial activation in iMgl/iNrn/iAstr triculture. 3) Determining the effect of cannabinoids on neurons and astrocytes in HIV infection and ART in iMgl/iNrn/iAstr triculture.