Spatial transcriptomic analysis reveals increased myofibroblast localization in patients with central centrifugal cicatricial alopecia

Summary: Previous transcriptomic and proteomic studies in central centrifugal cicatricial alopecia have identified several genes and canonical pathways associated with fibroblast activation, adaptive immune response, and dysregulated wound healing. However, key spatial information is lost using the aforementioned methods of analysis, limiting the ability to localize gene expression within the skin. To investigate gene expression patterns in CCCA patients while preserving the <i>in-situ</i> transcript localization, 3 treatment naive CCCA patients treated at a tertiary center were recruited. Two scalp biopsy samples were obtained from each patient: 1 from lesional scalp and 1 from non-lesional scalp. Spatial transcriptomic analysis was performed using Visium 10x Genomics. Spatial transcriptomic analysis of 8,410 genes identified 95 upregulated genes and 534 downregulated genes in lesional vs non-lesional scalp (p<0.05, absolute log2 fold changes [FC]>0.5). Gene set analysis revealed upregulation of pathways related to B cell activation, leukocyte differentiation, and Th17 cell lineage commitment. Downregulated pathways included those involved with keratinization, metabolic processes, hair cycle regulation, and epithelial cell differentiation (q<0.25). Notably, smooth muscle actin positive myofibroblasts, noted by ACTA2 expression, showed similar expression patterns in lesional and non-lesional scalp. However their distribution within the tissue differed, localizing around scarred hair follicles in lesional scalp and epithelial wall of blood vessels in non-lesional scalp. This study further supports the role of adaptive immunity in CCCA, while also highlighting the spatial differences of myofibroblasts in active disease. Increased myofibroblast localization around hair follicles instead of the vessels may offer key insights in disease pathogenesis. Future studies exploring fibroblast heterogeneity and localization patterns in CCCA may provide new insights into targeted therapies aimed at mitigating fibrosis. Jiana Wyche¹, Aaron Bao¹, Crystal Aguh¹ 1. Dermatology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States. Minoritized Populations and Health Disparities Research