MAIT Cells with High PFN1 Expression Mediate Immune Activation and Metabolic Reprogramming in Psoriasis

Psoriasis is a chronic inflammatory skin disease involving dysregulated immune responses and complex genetic factors. This study combines single-cell RNA sequencing (scRNA-seq), gene expression profiling, and genetic analysis to explore cellular and molecular contributors to psoriasis. Single-cell RNA-seq data (n = 3 psoriasis, n = 2 control; GSE228421) were used for cell-type annotation and functional characterization. T cell subsets were analyzed for differentiation trajectories and cell-cell communication. Differentially expressed genes in mucosal-associated invariant T (MAIT) cells were evaluated by enrichment analysis. Candidate gene causality was tested via eQTL-based Mendelian randomization (MR) and supported by bulk RNA-seq validation. MAIT cells were enriched in psoriatic lesions and exhibited strong intercellular interactions. Functional analyses revealed activation of IL6-JAK-STAT3 signaling, TNF-NFκB pathway, and glycolysis in MAIT cells. MR identified RPS20 as a protective factor (OR = 0.5994, p = 0.011) and PFN1 as a potential risk gene (OR = 1.7229, p = 0.037), with PFN1 highly expressed in MAIT cells. Colocalization analysis showed no significant genetic overlap between PFN1 expression and psoriasis risk. Metabolic profiling revealed differential pathway involvement in PFN1+ and PFN1- MAIT cells. Our integrative analysis highlights MAIT cells and PFN1 as likely contributors to psoriasis pathogenesis. These findings offer insights into immune and metabolic alterations, suggesting potential targets for therapeutic intervention.