MAPK14 as a key gene for regulating inflammatory response and macrophage M1 polarization induced by ferroptotic keratinocyte in psoriasis.

Psoriasis is a prevalent condition characterized by chronic inflammation, immune dysregulation, and genetic alterations, significantly impacting the well-being of affected individuals. Recently, a novel aspect of programmed cell death, ferroptosis, linked to iron metabolism, has come to light. This research endeavors to unveil novel diagnostic genes associated with ferroptosis in psoriasis, employing bioinformatic methods and experimental validation. Diverse analytical strategies, including "limma," Weighted Gene Co-expression Network Analysis (WGCNA), Least Absolute Shrinkage and Selection Operator (LASSO), Support Vector Machine Recursive Feature Elimination (SVM-RFE), and Random Forest (RF), were employed to pinpoint pivotal ferroptosis-related diagnostic genes (FRDGs) in the training datasets GSE30999, testing dataset GSE41662 and GSE14905. The discriminative potential of FRDGs in distinguishing between normal and psoriatic patients was gauged using Receiver Operating Characteristic (ROC) curves, while the functional pathways of FRDGs were scrutinized through Gene Set Enrichment Analysis (GSEA). Spearman correlation and ssGSEA analysis were applied to explore correlations between FRDGs and immune cell infiltration or oxidative stress-related pathways. The study identified six robust FRDGs - PPARD, MAPK14, PARP9, POR, CDCA3, and PDK4 - which collectively formed a model boasting an exceptional AUC value of 0.994. GSEA analysis uncovered their active involvement in psoriasis-related pathways, and substantial correlations with immune cells and oxidative stress were noted. In vivo, experiments confirmed the consistency of the six FRDGs in the psoriasis model with microarray results. In vitro, genetic knockdown or inhibition of MAPK14 using SW203580 in keratinocytes attenuated ferroptosis and reduced the expression of inflammatory cytokines. Furthermore, the study revealed that intercellular communication between keratinocytes and macrophages was augmented by ferroptotic keratinocytes, increased M1 polarization, and recruitment of macrophage was regulated by MAPK14. In summary, our findings unveil novel ferroptosis-related targets and enhance the understanding of inflammatory responses in psoriasis. Targeting MAPK14 signaling in keratinocytes emerges as a promising therapeutic approach for managing psoriasis.