Effects of PFOA and emerging alternatives at environmental concentrations on murine- and human-derived microglia: A comparative study.

Perfluorooctanoic acid (PFOA), a long-chain PFAS under regulatory scrutiny, is environmentally persistent and associated with neurotoxicity. Shorter-chain alternatives, including hexafluoropropylene oxide dimer acid (GenX) and perfluorobutanesulfonic acid (PFBS), have been widely adopted. However, their effects on microglia at environmental concentrations remain poorly explored. This study aimed to compare the neurotoxic potential of PFOA, GenX, and PFBS in human- and murine-derived microglia. Cells were exposed to graded concentrations (0, 0.1, 1, 10, 100, 1000, and 10,000 ng/mL) of three PFAS, respectively. Benchmark dose response analyses were conducted using the PROASTweb version 70.1 software. Oxidative stress indicators (ROS, CAT, MDA, SOD, GSH), pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), microglial phagocytic activity and activation markers, and TREM2/SYK signaling were determined. BMD data showed that PFOA exhibited greater neurotoxic potential than GenX and PFBS following 72 h of exposure. In addition, all three PFAS induced oxidative stress, microglial activation and phagocytic impairment, dysregulation of TREM2/SYK signaling in HMC3 and BV2. Furthermore, all three PFAS upregulated the expression of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α in HMC3. The result showed PFOA induced the more pronounced effects, with GenX and PFBS exerting progressively lesser effects. In conclusion, we found that all three compounds induce characteristic microglial dysfunction, including oxidative stress, inflammatory activation, and impaired phagocytic capacity, with the severity of damage following the hierarchy: PFOA > GenX > PFBS. This study provides comparative assessment of traditional versus emerging PFAS effects on both human and murine microglia, offering insight into the systematic profiling of the neurotoxicity of emerging PFAS alternatives during environmental health risk evaluations.