Dysregulation of neural activity and microglia function following exposure to the global environmental contaminant perfluorooctane sulfonate (PFOS)

Abstract

ABSTRACTPollution is a driving force in climate change and an important modifier of human health. Humans are chronically exposed to complex chemical mixtures and, correspondingly, researchers are disentangling the contribution of different contaminants to human neuropathologies. Per- and polyfluoroalkyl substances (PFAS) are biopersistent pollutants and, due to their diverse applications, have become global contaminants. Perfluorooctane sulfonate (PFOS), a prevalent PFAS congener, impairs humoral immunity; however, its impact on innate immunity is unclear. Given the critical roles of innate immune cells, namely microglia, in brain development and homeostasis, we asked whether exposure adversely affects microglial function. Herein, we demonstrate developmental PFOS exposure produces microglial activation and upregulation of the microglia activation gene p2ry12. PFOS-induced microglial activation heightened microglial responses to brain injury, in the absence of increased cell death or inflammation. Use of the photoconvertible calcium indicator CaMPARI revealed PFOS exposure heightened neural activity, while optogenetic silencing of neurons was sufficient to normalize microglial responses to injury. Exposure to perfluorooctanoic acid, an immunotoxic PFAS, did not alter neuronal activity or microglial behavior, further supporting a role for neural activity as a critical modifier of microglial function. Together, this study reveals how contaminant-induced changes in brain activity can shape brain health.