Brain Regional Dependence of Antiviral and Inflammatory Genes Following Simian Immunodeficiency Virus Infection and Antiretroviral Therapy

Abstract

Abstract Human immunodeficiency virus (HIV) initiates a perpetual cycle of inflammation in the brain that results in neuronal damage and consequent neurologic dysfunction. Since HIV preferentially infects and damages specific brain regions, there is a need for study of antiviral and immune markers in a brain region specific manner. We have evaluated expression of antiviral (IFNa, IFNb, TRAIL, MX1) and immune markers (CCL2, IL-6, IL-1b, IL-10) across nine brain regions in our virally suppressed rhesus macaque model of simian immunodeficiency virus (SIV) infection. Rhesus macaques from four study groups (uninfected, SIV, SIV/ART, SIV/ART cessation) were perfused, brain obtained by region, and snap frozen in liquid nitrogen. RNA was extracted and qRT-PCR performed to quantify the genes of interest in each brain region. Antiviral markers (MX1, TRAIL) were expressed in all brain regions and equally expressed across all groups, with occasional increase of MX1 in SIV infected animals. Alternatively, common immune markers (IL-6, CCL2) were not expressed across the brain regions of any study group, excepting the thalamus. Other antiviral (IFN-a) and immune markers (IL-10) were consistently expressed across brain regions in uninfected animals. However, the effects of SIV and ART on expression of these and other pertinent markers (IFN-b, IL-1b) were brain region dependent. Altogether, these data suggest that antiviral and immune marker expression is dynamic and differs depending on the marker and the brain region under investigation. This knowledge has implications for the way these markers are studied in the brain and implies a need for brain region specific investigation. Supported by grants from the NIH (5R01DA052859-02) and the NIH funded Johns Hopkins University Center for AIDS Research (P30AI094189-01A1)