Mechanism of Cannabidiol Effects on HIV Expression, Neuroinflammation, and HIV Cognitive Disease in Chronically-infected Immunocompetent Mice

This application is submitted in response to RFA-DA-20-022 and proposes basic research non-psychoactive commonly experienced by PLWH. However, its long-term HIV infection and progression of HIV disease remain largely undetermined. Our preliminary results in mice infected by chimeric HIV, EcoHIV, show that CBD has both anti-inflammatory and immunosuppressive functions in the brain; strikingly the canonical innate antiviral effector, interferon (IFN)-, was reduced in brains of infected CBD treated mice. Directly relevant to this RFA, we show that CBD increases HIV expression in mouse brain up to 10-fold. Moreover, despite anti-inflammatory effects of CBD alone, the drug failed to mitigate HIV mediated inflammatory gene expression. These results suggest that CBD use can increase HIV expression in PLWH and thereby exacerbate HIV-related diseases including NCI. We hypothesize that increased HIV brain infection by CBD results from its impairment of antiviral immunity including IFN functions. The Specific Aims are to: 1) Optimize CBD mediated increase in EcoHIV brain infection and assay its consequences in mouse behavioral tests including responses in the presence of antiretroviral drugs and during chronic infection, tests of CB receptor participation using knockout mice, and pilot HIV burden/ expression studies from brains of deceased PLWH using cannabis. 2) Determine beneficial or deleterious effects of CBD on HIV control by immunity in brains of EcoHIV-infected mice including assay of antigen-specific responses ex vivo, innate responses in vivo and ex vivo, and gene expression profiling of brain lymphocyte, macrophage and microglia by single cell RNA- seq and bioinformatics. 3) Using information from Aim 2, test the hypothesis that CBD increases HIV expression in the brain and NCI by disruption of IFN responses including assay of post-transcriptional modification in IFN induction, epigenetic modification in promoters of IFN stimulated genes, and IFN specificity using knockout mice. Our approaches will include combined CBD and antiretroviral treatment of EcoHIV- infected mice, QPCR for measurement of virus burden in tissues, behavioral tests of learning, isolation and functional evaluation of mononuclear cells from the brain, brain cell lineage specific RNA seq, mechanistic studies of CBD effects upon IFN signaling pathways and epigenetic changes determining IFN responsive gene expression, key receptor knockout mice for responses to EcoHIV/CBD, and curated brain tissue from NNTC of HIV-infected persons using cannabis and no other drugs of abuse. This application meets the RFA requirements of “research models of chronic/persistent HIV-induced inflammation under conditions of ART”; for evaluation of “the role of cannabinoids in HIV-associated chronic inflammation”; and to “Delineate ….. beneficial or deleterious effects of cannabinoid use on HIV-induced inflammation”. science and preclinical in EcoHIV-infected mice to model cannabidiol (CBD) effects in people living with HIV (PLWH). CBD, a cannabis component, is freely available and widely used for relieving pain and anxiety effects on