JAK1/2 Inhibitors Alleviate the Damage of Intercellular Adhesion by Reducing Endoplasmic Reticulum Stress-Induced Apoptosis in Pemphigus Vulgaris.

Pemphigus vulgaris (PV), a severe autoimmune disease with high morbidity and mortality, necessitates innovative therapies to improve outcomes while minimising the adverse effects of conventional immunosuppressants. Immunohistochemical analysis revealed elevated phosphorylated Janus kinase (p-JAK)1 and p-JAK2 expression in PV lesions, complemented by transcriptome data showing JAK/STAT pathway dysregulation. Using a PV acantholysis model, we demonstrated that Ruxolitinib, a JAK1/2 inhibitor, significantly reduced keratinocyte apoptosis, enhanced cell adhesion, and alleviated endoplasmic reticulum (ER) stress. Additionally, Ruxolitinib mitigated tunicamycin-induced ER stress and apoptosis in HaCaT cells. These findings establish a crucial role for JAK1/2 in PV pathogenesis, demonstrating that their inhibition alleviates ER stress, reduces apoptosis, and improves cell adhesion. Our results provide a theoretical foundation for the clinical application of JAK inhibitors in PV treatment.