Cannabinoid Receptor 2 Agonists Attenuate HIV Replication and Inflammatory Activation in HIV-infected Myeloid Cells

Emerging evidence suggests brain-resident myeloid cells, including macrophages and microglia, provide a reservoir for HIV infection in the central nervous system (CNS), and their inflammatory activation is a proposed pathogenic mechanism in HIV-associated neurocognitive disorders (HAND). We investigated whether cannabinoid receptor 2 (CB2), an immunomodulatory receptor expressed in myeloid cells, regulates viral replication and inflammation in HIV-infected macrophages and microglia. Using the synthetic CB2-specific agonist, JWH-133, we found that CB2 activation reduces HIV replication in primary human monocyte-derived macrophages (MDMs) and human iPSC-derived microglia (iMg) at differing doses, corresponding to the basal expression of CNR2 and related endocannabinoid transcripts in each cell type. Direct CB2 agonism via JWH-133 broadly reduced cytokine release from HIV-infected MDMs, but not iMg. RNA-seq revealed that CB2 agonism primarily altered interferon and integrated stress response pathways in MDMs; homeostatic pathways, including synapse maintenance and phagocytosis, were altered in iMg. Further investigation in iMg found NLRP3 inflammasome activation, but not priming, was reduced by CB2 activation. This study identifies key discrepancies in CB2 response between myeloid cell types and implicates CB2-specific agonists as promising candidates for regulation of HIV-associated neuroinflammation. Overall design: Human primary monocyte-derived macrophages (MDM) and iPSC-derived microglia (iMg) underwent true or mock infection with HIV-ADA. 24 hours after HIV infection, samples were treated with vehicle (DMSO) or 1 uM JWH-133, a cannabinoid receptor 2-specific agonist. Infected cultures were maintained for 9 days,with cannabinoids replaced during media change every 48 hours. RNA was extracted on day post infection 9 to assess the myeloid cell-type specific responses to HIV infection and concurrent CB2 activation.