Transcriptome Response and Protein Abundance are Correlated with Split Formation and Cell Detachment as Secondary Effects to Autoantibodies in Human Skin Organ Culture Models for Pemphgus Vulgaris

Pemphigus vulgaris (PV) is an autoimmune disease caused by autoantibodies (AAbs) targeting Desmoglein 1 (DSG1) or Desmoglein 3 (DSG3) on keratinocytes, leading to disrupted cell-cell adhesion and epidermal blistering. To investigate the early signaling events triggered by AAb binding, we examined transcriptomic and proteomic responses in a human skin organ culture (HSOC) model for PV. After injecting the single-chain variable fragment (scFv) PX43, which targets DSG1 and DSG3, or the mouse-derived DSG3 AAb AK23, we quantified transcriptome changes at 0, 5, 10, and 24 hours and proteome responses at 0 and 24 hours, using human or murine IgG as controls. Differential pathway regulation was analyzed over time using gene set variation and enrichment analysis, with pathway responses compared to in vitro and in situ responses of normal human epithelial keratinocytes (NHEKs) under conditions such as stretching, differentiation, migration, detachment, and acute wounding. Only PX43 induced split formation in the HSOC model, which was associated with significant transcriptomic and proteomic changes, while AK23 did not alter gene expression or protein levels. Enriched pathways in response to split formation included TNFα, Interferon α/γ, IL2-STAT5, and IL5-STAT3 signaling across all time points. The transcriptomic response closely resembled that of acute skin wounding and keratinocyte detachment, with an inverse correlation to cell stretching and differentiation and no correlation to keratinocyte migration. These findings indicate that AAbs targeting DSG1 and/or DSG3 alone do not drive broad transcriptomic or proteomic changes; rather, observed changes result from split formation, resembling the response to wounding and inflammation. Human skin organ cultures were injected with DSG-targeting PX43 (DSG1 and DSG3) or AK23 (DSG3) antibodies, with transcriptome data collected by RNA-seq at 0, 5, 10, and 24 hours post-stimulation, using human or murine IgG as controls.