Methamphetamine and Antiretroviral Therapy Impact Macrophage Functions and Macroautophagy: Implications for HIV Neuropathogenesis

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Project Abstract Myeloid cells, microglia and monocyte derived macrophages (MDM), are long-lived cellular reservoirs for HIV in the CNS not eliminated by effective antiretroviral therapy (ART). Despite ART, infected cells become activated and damaged, leading to the development of HIV-associated neurocognitive disorders, or HAND. Approximately 15-40% of people living with HIV (PLWH) have some form of HAND despite ART. Methamphetamine (meth) use can facilitate HIV transmission and may increase CNS damage in meth users, including PLWH. We will characterize how meth impacts microglia/MDM mediated inflammatory processes that contribute to CNS damage in PLWH taking ART. We will also determine how changes in these cellular functions in response to meth and ART may be regulated by macroautophagy. Macroautophagy is a homeostatic, catabolic process in which damaged and toxic proteins, organelles, and pathogens are targeted for cytosolic degradation in the lysosome. Some studies have shown that macroautophagy may, in part, regulate functions of microglia/MDM that contribute to CNS damage and HAND. We hypothesize that meth and ART impact autophagy in microglia/MDM, leading to impaired clearance of extracellular debris and increased neurotoxic ROS, cytokine, and glutamate secretion to contribute to neurological damage in people taking meth and ART. To study this hypothesis, we developed two aims: Aim 1: To determine the impact of meth and ART on cellular functions of uninfected and HIV-infected human microglia and monocyte derived macrophages (MDM) that contribute to HAND. We will determine how meth and ART impact phagocytosis, ROS production, cytokine secretion, and glutamate release using fluorometry, microscopy, flow cytometry, and ELISA. Aim 2: To characterize how meth and ART impact macroautophagy in uninfected and HIV- infected human microglia and monocyte derived macrophages (MDM), and determine how macroautophagy regulates meth and ART mediated changes in functions that contribute to HAND. We examine how meth and ART change general and selective autophagic processes using high-content microscopy and Western blotting. We will also genetically inhibit macroautophagy or use drugs that inhibit or activate autophagy to determine further how autophagy may regulate meth and ART induced changes in phagocytosis, ROS, cytokine secretion, and glutamate release. With this knowledge, we can develop therapies that impact macroautophagy to mitigate microglial/MDM mediated CNS damage, reducing HAND in meth users living with HIV.