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

Background: 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.

Methods: 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.

Results: 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.

Conclusion: 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.