Simian Immunodeficiency Virus and Antiretroviral Therapy Impact Rhesus Macaque Brain Lipid Distribution

Human immunodeficiency virus (HIV) infection promotes considerable bioenergetic, spatially heterogenous strain to the brain that is incompletely ameliorated through viral suppression afforded by antiretroviral therapy (ART). Disrupted homeostasis of brain lipids after HIV in humans or simian immunodeficiency virus (SIV) infection in rhesus macaques occurs due to elevated energetic demands, neuroinflammation, reactive oxygen species, and barrier leakiness. Brain lipids are particularly vulnerable to HIV-associated dysregulation due to their high abundance, unique composition, and specialized functional roles. Using rhesus macaques exposed to SIV and ART (tenofovir disoproxil fumarate (TDF), emtricitabine (FTC), and dolutegravir (DTG), we investigated the spatial distribution and abundance of lipids across brain regions and metabolically relevant peripheral tissues using mass spectrometry imaging. When comparing lipid abundance, individual lipids representing a multitude of species were more varied across tissues than by treatment condition. Further, we discerned either solely SIV infection or ART outweighed one another in altering phospholipids in different tissues Presence of ART had a greater influence on phospholipid homeostasis in the temporal cortex and hippocampus than in the midbrain, possibly due to differences in penetrance and turnover of ART across brain regions. Overall, these data demonstrate ART robustly increased phospholipids across brain regions while SIV infection had a varied impact depending on the brain region. These findings inform the need to further evaluate the neurologic consequences that may result in the brain due to disrupted lipid homeostasis across ART regimens.