HIV-1 remains an incurable disease and as of 2017 over 30 million people were estimated to be living with HIV-1 with an average of 1.8 million new infections occurring annually. Up to 50% of people with HIV (PWH) suffer from HIV-associated neurocognitive disorders (HAND) despite effective combination anti-retroviral therapy (cART). HAND therefore represents a significant cause of morbidity in PWH. The inability of cART to prevent viral transcription and neurocognitive dysfunction confirms the need for adjunct therapies that target underlying mechanisms that contribute to HAND. In this context, mechanisms that may contribute to HAND include delivery of selective cargo in extracellular vesicles (EVs) released from HIV-infected macrophages/microglia. The long-term goal of this proposal is to mitigate virally-mediated pathogenesis within the CNS. The short term goals including elucidating the role of the cannabinoids in the inhibition of viral transcription and the reduction in the release of extracellular vesicles containing viral RNAs and proteins which cause CNS dysfunction. Our preliminary data suggests that the cannabinoids, cannabidiol (CBD) and ?9-tetrahydrocannabinol (THC), may be effective in reducing HIV-1 transcription of both short, non-coding RNA such as trans-activating response (TAR) RNA and full- length genomic RNA, thereby resulting in a decreased production of infectious virus. Additional data indicates that the reduction in transcription results in a decreased incorporation of HIV-1 RNA into EVs released from infected cells, which has been previously shown to contribute to dysfunction in recipient cells including activation of the NF- kB pathway through TLR3 and increased susceptibility to infection. The data suggests this therapeutic effect is further amplified as treatment with cannabinoids results in a significant reduction in the number of EVs released from HIV-1 infected cells. We hypothesize that cannabinoid treatment may affect host cell pathways, including autophagy and the endosomal sorting complexes required for transport (ESCRT) pathways, to alter EV release which can potentially mitigate EV-related dysfunction during viral infection of the CNS.
Our Aim i nclude: 1) To define the mechanisms of cannabinoid-mediated decreased EV production and release in HIV-1 infected cells, and 2) Effect of CBD and THC on HIV-1 expression using 3D neurospheres. The overall positive impact of these two aims are to highlight the role of cannabinoids in EV release and dampening of the neuroinflammation.
The current proposal is innovative as it utilizes CBD and THC to score for down regulation of Extracellular Vesicles (EVs) from infected latent cells and 3D cultures. Despite the development of combination antiretroviral therapy (cART), which effectively suppresses viral replication, HIV-associated neurocognitive disorders HAND is still reported to affect up to 50% of HIV-1 infected individuals. In collaboration with ATCC, we have generated 3D neuronal cultures using neural stem cells/neural progenitor cells to self-assemble into spheres over time, and these cultures can be infected with HIV-1 and regulated with cART, without affecting viral transcription.