Project Grant R01NS137852

EPIGENETIC PROFILING OF HIV-ASSOCIATED NEUROINFLAMMATION AND PROVIRAL EXPRESSION IN THE BRAIN - ABSTRACT BACKGROUND: HIV INFECTION IN THE BRAIN OCCURS EARLY AFTER TRANSMISSION AND LEADS TO CHRONIC NEUROINFLAMMATION. ALTHOUGH MODERN ANTIRETROVIRAL THERAPY (ART) CONTROLS VIRAL REPLICATION, THERE IS NO CURE FOR HIV, AND SUCCESSFUL CONTROL OF VIRAL REPLICATION HAS NOT COMPLETELY AMELIORATED INFLAMMATION AND HIV-ASSOCIATED NEUROCOGNITIVE DISORDERS (HAND). MICROGLIA PLAY A CENTRAL ROLE IN OTHER NEURODEGENERATIVE DISORDERS AND ARE THE LIKELY PRIMARY RESERVOIR FOR HIV IN THE BRAIN, BUT LITTLE ELSE IS KNOWN ABOUT THE INFLAMMATORY CHARACTER ASSOCIATED WITH HAND. ADDITIONALLY, THE INFLAMMATORY INCITEMENT ASSOCIATED WITH HIV IS POTENTIALLY DETERMINED BY ITS EXPRESSION OF VIRAL PROTEINS, DICTATED BY THE EPIGENETIC MICROENVIRONMENT OF THE PROVIRUS, WHICH IS POORLY CHARACTERIZED. RECENTLY, THE NURR1 RECEPTOR WAS DESCRIBED AS AN IMPORTANT MEDIATOR OF HIV-1 SILENCING IN THE CONTEXT OF MICROGLIA IN VITRO, MAKING IT A PROSPECTIVE FOCAL POINT FOR FURTHER STUDIES IN BRAIN TISSUE. STUDY COHORT: WE WILL LEVERAGE THE UNIQUE LAST GIFT RAPID AUTOPSY COHORT, WHICH ALLOWS US TO PRESERVE CELLULAR INTEGRITY AND NUCLEIC ACIDS IN PRECIOUS TISSUE SAMPLES COLLECTED FROM PWH. WE WILL SELECT FRONTAL CORTEX AND BASAL GANGLIA FROM 15 LAST GIFT PARTICIPANTS TO ANALYZE FOR THIS PROPOSAL. OUR GOAL: USING POWERFUL SINGLE CELL SEQUENCING TECHNIQUES, WE WILL CHARACTERIZE THE EPIGENETIC REGULATORS OF THE HIV PROVIRUS IN BRAIN MYELOID CELLS FROM 15 PWH USING NOVEL EPIGENETIC ENRICHMENT TECHNIQUES AND ASSIMILATED DATA ON INTEGRATION SITES AND THE FULL-LENGTH PROVIRAL SEQUENCE GENERATED AS PART OF THE LAST GIFT PROJECT (AIM 1). NEXT, USING BRAIN MYELOID CELLS ISOLATED FROM A SUBSET OF THE PARTICIPANTS (N=6), WE WILL FURTHER EXPLORE THE MECHANISTIC FRAMEWORK OF THE HIV PROVIRUS IN MICROGLIA THROUGH MANIPULATION OF THE PROVIRAL EPIGENETIC PROFILE USING IN VITRO NURR1 AGONISTS AND EPIGENETIC MODULATORS (AIM 2). FINALLY, WE WILL USE SINGLE CELL TECHNIQUES TO EXAMINE THE EPIGENETIC AND TRANSCRIPTOMIC PROFILE OF THE INFLAMMATORY MILIEU IN THE BRAINS OF PWH ON SUPPRESSIVE ART AND CORRELATE THEM WITH PROVIRAL LOAD AND CELL-ASSOCIATED VIRAL RNA (AIM 3). HOW WILL WE ADVANCE THE FIELD? THE EPIGENETIC CHARACTERISTICS OF THE HIV PROVIRUS HAVE NOT BEEN EXAMINED IN THE BRAINS OF PEOPLE WITH HIV (PWH). MOST EVALUATION OF PROVIRAL EPIGENETICS HAS BEEN FOCUSED UPON CD4+ T CELLS, BUT THUS FAR FEW HAVE EXAMINED EPIGENETIC MECHANISMS OF PROVIRAL REACTIVATION IN MICROGLIA FROM PWH, AND NONE HAVE BEEN ABLE TO DEFINE THESE MECHANISMS THOROUGHLY IN TISSUE SAMPLES OR CELLS ISOLATED FROM BRAINS OF PWH. THEREFORE, THIS PROPOSAL WILL ADVANCE OUR UNDERSTANDING OF HIV PERSISTENCE IN THE BRAIN ON MULTIPLE FRONTS. ADDITIONALLY, THE INFLAMMATORY PATHOGENESIS OF NCI IN HIV INFECTION IS POORLY CHARACTERIZED, BUT OUR PROPOSAL WOULD NOT ONLY ALLOW DEFINITION OF THE IMMUNE CELL CHARACTER IN THE BRAINS OF PWH, BUT ALSO THE EPIGENETIC AND TRANSCRIPTOMIC MECHANISMS AT PLAY IN ALL CELL TYPES, INCLUDING NEURONS AND ASTROCYTES.