The Role of Endothelial Injury and Myeloid Cell Migration in the Activation of Inflammasomes in HIV infection and Cocaine Exposure - Combination anti-retroviral therapy (cART) reduces HIV-1 replication, viral load and increases survival of people living with HIV-1 (PLWH). PLWH who receive cART PLWH who receive cART are still under the risk of developing HIV-1-associated neurocognitive disorders (HAND). Chronic neuroinflammation is a critical factor for HAND pathogenesis. HIV-1 proteins (Tat, Vpr, Vpu and gp41) that expressed without HIV-1 replication induce inflammasome activation in chronic microglia and macrophages infection. Cocaine enhances HIV-1 replication in microglia in vitro. In HIV infected macrophages in the presence of cocaine, significant upregulation of NLRP3 gene and ROS production has been observed. Therefore, both cocaine and HIV-1 proteins may act synergistically to enhance inflammasome activation and neuroinflammation. We demonstrated that HIV-1 causes abnormal distribution of macrophages in the lungs of HIV-Tg mice after LPS administration, and inhibition of HIV-1 transcription restores normal macrophages distribution. Cocaine, which increases the permeability of the blood-brain barrier, may impact monocyte/macrophages migration. We hypothesize that cocaine exposure induces endothelial injury and increases accumulation of perivascular macrophages and microglia in HIV-Tg mice. We further hypothesize that HIV-1 proteins, cocaine, and DAMP signals from injured endothelial cells synergistically increase inflammasome activation. We propose that HIV-1 proteins will impair trans-endothelial migration of macrophages and reduce microglial migration towards the injured vessels, leading to prolonged inflammation. In Specific Aim 1, we will characterize myeloid cell populations in different brain locations in HIV- Tg mice under chronic cocaine treatment. We will evaluate a number, distribution and inflammasome activation in brain myeloid cells in HIV-Tg mice under cocaine exposure by immunostaining, RT-PCR and flow cytometry analysis of isolated myeloid cells. In Specific Aim 2, we will evaluate accumulation of perivascular macrophages and microglia around the vessels after cocaine exposure. We will test accumulation of macrophages and microglia around vessels after acute and chronic exposure of HIV-Tg mice to cocaine. Our hypothesis proposed in this application, if proven correct, would demonstrate that cocaine-induced endothelial damage enhances inflammasome activation and increases the accumulation of myeloid cells around vessels. The potential implications of this discovery could be used to develop novel therapeutic treatments that inhibit HIV-1 transcription or decrease brain endothelial injury.
