Chronic binge alcohol-induced hippocampal plasticity in SIV-infected female rhesus macaques

Abstract

Human immunodeficiency virus (HIV) infection is detrimental to central nervous system (CNS) function and may result in HIV-associated neurocognitive disorder (HAND) over time. HIV-associated cognitive deficits are further exacerbated by chronic alcohol use. With the rising prevalence of alcohol use disorder (AUD) in females and people living with HIV (PLWH), understanding the neurobiological impact of chronic alcohol exposure in these populations is increasingly important. As the hippocampus plays a prominent role in cognition, examining neuroadaptations in this brain region in the context of comorbid HIV infection and alcohol exposure is critical for understanding the mechanisms of neurocognitive impairment. We hypothesized that simian immunodeficiency virus (SIV)-infected female rhesus macaques with a history of chronic binge alcohol (CBA) administration (n=7-8 per group) would exhibit increased phosphorylation of mitogen-activated protein kinase (MAPK) family members, indicative of increased hippocampal activity and potential hyperexcitability. We also measured cognitive performance in macaques via the novel object recognition (NOR) task and further hypothesized a manifestation of cognitive deficits in the CBA-treated group. Finally, we incorporated additional groups of ovariectomized (OVX) females in the design as we hypothesized that the loss of ovarian hormones would reduce cognitive performance. Data were analyzed via two-way ANOVA with CBA treatment and OVX as factors. Western blot analyses demonstrated that CBA significantly increased phosphorylation of MAPK-family members extracellular signal-regulated kinase (ERK; F=8.278, p=0.0093) and p38 mitogen-activated protein kinase (p38 MAPK; F=4.414, p=0.0485). Furthermore, CBA significantly increased both phosphorylated and total levels of Jun N-terminal kinase (JNK; F=5.989, p=0.0233; F=7.158, p=0.0145). While analysis of the NOR task revealed a significant reduction in latency to approach the novel versus familiar object on test day across all groups (F = 11.97, p=0.0013), no significant difference was seen between CBA and control groups. Interestingly, no main effects of OVX or interactive CBA/OVX effects were observed for either molecular or behavioral outcomes. We are currently considering alternative cognitive tasks that may better reveal CBA-associated cognitive deficits, as well as neuroadaptations in nuclear signaling downstream of MAPK activity. Together, these data suggest that chronic alcohol use results in profound changes in hippocampal plasticity, potentially facilitating cognitive decline and other CNS symptoms observed in PLWH. This research was supported by grant # T32AA007577 and #P60AA009803 from the NIAAA at the National Institutes of Health. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.