Spatial transcriptomic analysis identifies markers of neuroinflammation and keratinocyte hyperproliferation in prurigo nodularis

Summary: Abstract Body: Prurigo nodularis (PN) is a chronic inflammatory skin disorder characterized by intense pruritus and nodular skin lesions, yet its underlying molecular mechanisms remain poorly understood. Neuroinflammation and epidermal barrier dysfunction are emerging as key contributors to PN pathophysiology. To investigate the spatial expression of relevant genes, we employed spatially resolved RNA sequencing using the Visium Spatial Gene Expression platform (10x Genomics) on lesional and non-lesional skin biopsies from 12 PN patients and 4 healthy controls. Our analysis identified significant upregulation of S100A8, S100A9, GJB2, S100A7, SPRR2G, LCE3D, KRT16, and FABP5 in lesional PN skin compared to healthy controls (p<0.05). The S100A8 and S100A9 genes encode calprotectin, a complex implicated in amplifying inflammatory responses via activation of Toll-like receptor 4 (TLR4) and the receptor for advanced glycation end-products (RAGE). Their upregulation suggests a pro-inflammatory milieu contributing to chronic neuroinflammation in PN. Similarly, elevated expression of GJB2 and S100A7, known mediators of epidermal barrier integrity and antimicrobial defense, aligns with impaired barrier function observed in PN. The upregulation of SPRR2G, LCE3D, and KRT16, genes associated with keratinocyte activation and hyperproliferation, highlights epidermal remodeling and stress responses central to PN pathogenesis. Spatial co-expression patterns revealed localization of S100A8/9 and GJB2 within dermal immune clusters, suggesting potential interactions between neuroimmune pathways and keratinocyte signaling. These findings underscore the role of neuroinflammation and keratinocyte hyperproliferation in PN, providing novel insights into its molecular landscape. Selina M. Yossef^{2, 1}, Shahin Shahsavari², Jonathan Wang², Shirin Shahsavari², Kavita Vats², Louis J. Born², Yagiz M. Akiska², Davies Gage², Madan M. Kwatra^{1, 3}, Shawn Kwatra² 1. Anesthesiology, Duke University, Durham, NC, United States. 2. Dermatology, University of Maryland Baltimore School of Medicine, Baltimore, MD, United States. 3. Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, United States. Cell Communication Networks and Stromal Biology