Single-cell and spatial transcriptomics of vulvar lichen sclerosus reveal multi- compartmental alterations in gene expression and signaling cross-talk

Vulvar diseases are a critical but often overlooked issue in women's health, impacting many women and frequently causing long-term physical and emotional challenges. Lichen sclerosus (LS) is a chronic inflammatory skin disease that causes scarring of the vulva and is associated with an increased risk of malignancy. The molecular pathogenesis of vulvar LS (VLS) is not well understood, preventing development of any FDA-approved therapies. Here, we utilize single-cell and spatial transcriptomics to analyze lesional and non-lesional skin from VLS patients, as well as healthy control vulvar skin. Our studies, which reveal histologic, cellular, and molecular heterogeneities within VLS, also identify unifying molecular changes across fibroblasts, immune cells, keratinocytes, and melanocytes in lesional skin. The findings depict a scenario of cellular stress and damage affecting both fibroblasts and keratinocytes, along with a complex immune landscape indicating enhanced CD8+ T cell cytotoxicity but also signs of exhaustion. They further suggest aberrant cell-cell signaling across, and increased activation of IFN, JAK/STAT, and p53 pathways in specific cell types. Using monolayer and organotypic culture models, we demonstrate that the depletion of select genes, which are downregulated in VLS lesional skin keratinocytes, partially recapitulates VLS-like stress-associated changes. Collectively, these data provide novel insights into the pathogenesis of VLS, identifying potential biomarkers and therapeutic targets for future research.