Linking IFN-γ-Mediated Pathogenesis to ROCK-Targeted Therapy in a Scalable iPSCs-Based Vitiligo Model.

Vitiligo is a chronic autoimmune dermatosis defined by selective melanocyte depletion and patchy depigmentation. IFN-γ-driven recruitment of autoreactive CD8(+) T cells and induction of melanocyte apoptosis are central to its pathogenesis. Current therapies-including UVB phototherapy, tacrolimus, vitamin D3 analogs, and surgical methods-show limited and inconsistent efficacy. Emerging treatments like JAK inhibitors and WNT activators offer potential but require further validation. Translational progress is hindered by a lack of scalable human models. Here, we describe a tunable in vitro vitiligo platform in which human iPSC-derived melanocytes (iMc) are co-cultured with keratinocytes on Matrigel and exposed to precise graded IFN-γ concentrations. Our data revealed dose-dependent decreases in iMc survival and dendritic structure, faithfully mirroring derived melanocyte pathology. Leveraging this platform, we first evaluated the short-term efficacy of the ROCK inhibitor Y27632 under early-stage patient IFN-γ concentrations representative of patient lesional thresholds. At three days, Y27632 significantly upregulated adhesion molecules E-cadherin and DDR1, and two central factors-ET1 and bFGF. Importantly, ROCK inhibition reversed dendritic retraction and improved overall viability of iMc-keratinocytes. These findings position ROCK blockade as a promising adjunctive strategy and establish a pre-clinical platform for evaluating combination therapies for durable pigment restoration.