Abstract
HIV-associated neurocognitive impairment (HIV-NCI), a comorbidity of human immunodeficiency virus (HIV) infection, affects up to 50% of people with HIV (PWH). HIV-infected monocytes that transmigrate across the blood-brain barrier and mature into macrophages establish a central nervous system (CNS) viral reservoir that activates and infects parenchymal cells, contributing to neuronal damage that characterizes HIV-NCI. Methamphetamine (meth) use is prevalent in PWH and further impairs cognitive functioning. To examine whether meth-mediated dysregulation of macrophage functions may contribute to increased HIV-NCI, we characterized differential gene expression in primary human HIV-infected macrophages treated daily with meth for five days by RNA-sequencing. We identified increases in multiple gene isoforms of metallothionein 1 (MT1), a heavy metal binding protein involved in protective mechanisms against metal toxicity and oxidative stress. Nuclear localization of MT1 protein was previously shown to either positively or negatively affect nuclear factor κB (NF-κB) activity in a cell type specific manner, with nuclear MT1 contributing to LPS-induced TNF-α and IL-6 in macrophages. We found that daily meth treatment for one to five days increased nuclear localization of MT1 in macrophages acutely infected with HIV which was associated with increased LPS-induced CXCL8 and CCL8, and a trend towards increased basal and/or LPS-induced expression of other cytokines/chemokines, including TNF-α and IL-6, that was donor specific. Reactive oxygen species (ROS) levels were not changed with meth treatment although there was a donor specific trend towards increased ROS with multiple days of meth treatment. These data indicate that repeated exposure of macrophages to meth in the context of HIV increases nuclear MT1 localization, which is associated with increased inflammatory mediator production, and therefore may be a mechanism that contributes to meth-mediated exacerbation of HIV-NCI.