Multi-Omics Integrated Analysis Reveals Correlative Signatures of Short-Chain PFAS Mixtures on Mouse Midbrain Dopaminergic Neurons Involving the TM/5-HT Pathway

This study aimed to identify candidate molecular pathways mediating dopaminergic dysfunction induced by PFAS mixture exposure, with a focus on the TM/5-HT signaling axis and calcium-linked lipid metabolites, and to explore potential gut-brain axis involvement. Adult mice were exposed to a PFAS mixture. Behavioral tests assessed spatial memory, spontaneous activity, and motor coordination. Histopathological and ultrastructural analyses examined neuronal atrophy, mitochondrial damage, α-synuclein (α-syn), and tyrosine hydroxylase (TH). Transcriptomics, metabolomics, and gut microbiota profiling (16S rRNA sequencing) were performed, followed by integrated multi-omics and correlation analyses. PFAS exposure was associated with PD-relevant motor and cognitive impairments, including impaired spatial memory, reduced spontaneous activity, and motor coordination deficits. Neuronal atrophy, mitochondrial structural damage, upregulation of α-syn, and downregulation of TH were observed. Transcriptomics identified 315 differentially expressed genes (DEGs) enriched in ciliary movement, neuroactive ligand-receptor interactions, and serotonergic synapses. Metabolomics identified 130 differentially abundant metabolites involved in arachidonic acid metabolism and serotonergic synapses. Integrated analysis highlighted correlative changes in the TM/5-HT signaling pathway. Phosphatidylinositol PI(16:0/20:2(11Z,14Z)) showed a strong positive correlation with Dbh gene expression, suggesting a candidate association between Dbh expression and phosphatidylinositol alterations. Gut microbiota analysis revealed compositional alterations (e.g., Muribaculaceae, Ileibacterium) and predicted functional shifts (e.g., tryptophan metabolism–related modules) were observed; these findings are exploratory. This study identifies multi-omics signatures associated with PFAS mixture-induced dopaminergic dysfunction in mice. The TM/5-HT pathway emerges as a candidate molecular axis requiring further investigation. Gut microbiota alterations suggest a potential peripheral component, but causality and gut-brain axis involvement remain hypothetical and need direct experimental validation.