Activated wound phenotype and microbial dysbiosis are driven by AhR suppression in hidradenitis suppurativa tunnels

Summary: Abstract Body: Tunnels drive advanced disease in hidradenitis suppurativa (HS); however, dysregulation in tissue repair and the microbiome within these intradermal structures remains poorly understood. We characterized the cellular phenotypes and microbiome of HS tunnel tissue and explored the role of microbiome-sensing AhR pathway as a mechanistic mediator. Comparative gene ontology (GO) and Ingenuity pathway analysis (IPA) were performed using bulk RNAseq and scRNAseq data from tunnel and peri-lesional tissue, complemented with16s rDNA microbiome profiling from tunnel tissue. Furthermore, we isolated and isolated keratinocytes (HK), fibroblasts (FB), and bacteria from the above tissues and validated omics data using in vitro assays, immunohistochemistry (IHC), and qPCR. Controls from peri-lesional skin and location/age/gender matched skin. GO analysis showed enrichment in acute wound healing processes in tunnel tissue, confirmed by “wound activated” keratin 17 uniquely expressed in tunnel and not peri-lesional epidermis as confirmed by IHC and qPCR. Tunnel HK also showed faster migration compared to peri-lesional HK, an effect modulated by AhR active drugs. IPA revealed decreased AhR signaling in tunnel HK, including suppression of CYP1A and CYP1B, aligning with the reduced abundance of commensal bacteria in tunnels, including Cutibacterium and Lactobacillus species. In addition, tunnel FB showed increased contractility in our 3D HS tunnel organotypic, mimicking activated wound phenotype. Using multiple omics approaches and validation, we show that the persistent activated wound cellular phenotype and unfettered inflammation in HS tunnels correlate with dysbiosis and suppression of AhR signaling. Our data complements previous studies showing that skin microbiota mediate cutaneous barrier repair through AhR signaling. We provide novel insights into HS pathogenesis and rationale for therapeutic targeting of AhR in HS tunnels. Raji R. Nagalla¹, Nathan Balukoff¹, Jelena Marjanovic¹, Ali Kamiar¹, Andrew Sawaya¹, Elina Zhivov¹, Barry I. Resnik², Hadar Lev-Tov¹, Marjana Tomic-Canic¹, Irena Pastar¹ 1. Dermatology, University of Miami Miller School of Medicine, Miami, FL, United States. 2. Resnik skin Institute, Miami, FL, United States. Stem Cell Biology, Tissue Regeneration and Wound Healing