Evidence of pyroptosis and ferroptosis extensively involved in autoimmune diseases at the single-cell transcriptome level.

BACKGROUND: Approximately 8-9% of the world's population is affected by autoimmune diseases, and yet the mechanism of autoimmunity trigger is largely understudied. Two unique cell death modalities, ferroptosis and pyroptosis, provide a new perspective on the mechanisms leading to autoimmune diseases, and development of new treatment strategies. METHODS: Using scRNA-seq datasets, the aberrant trend of ferroptosis and pyroptosis-related genes were analyzed in several representative autoimmune diseases (psoriasis, atopic dermatitis, vitiligo, multiple sclerosis, systemic sclerosis-associated interstitial lung disease, Crohn's disease, and experimental autoimmune orchitis). Cell line models were also assessed using bulk RNA-seq and qPCR. RESULTS: A substantial difference was observed between normal and autoimmune disease samples involving ferroptosis and pyroptosis. In the present study, ferroptosis and pyroptosis showed an imbalance in different keratinocyte lineages of psoriatic skinin addition to a unique pyroptosis-sensitive keratinocyte subset in atopic dermatitis (AD) skin. The results also revealed that pyroptosis and ferroptosis are involved in epidermal melanocyte destruction in vitiligo. Aberrant ferroptosis has been detected in multiple sclerosis, systemic sclerosis-associated interstitial lung disease, Crohn's disease, and autoimmune orchitis. Cell line models adopted in the study also identified pro-inflammatory factors that can drive changes in ferroptosis and pyroptosis. CONCLUSION: These results provide a unique perspective on the involvement of ferroptosis and pyroptosis in the pathological process of autoimmune diseases at the scRNA-seq level. IFN-γ is a critical inducer of pyroptosis sensitivity, and has been identified in two cell line models.