Single cell sequencing reveals the presence of cancer-associated fibroblasts in cutaneous neurofibromas

Summary: Abstract Body: Cutaneous neurofibromas (CNs) are a manifestation of neurofibromatosis type 1 (NF1) that cause significant psychosocial burden to patients. Little is known about the cellular interactions within CNs. We assessed the cellular makeup of 7 CNs from 6 different NF1 patients using single-cell RNA sequencing analysis (scRNA-seq). We determined the genetic markers for each cell type cluster and ascertained the cell identity for each cluster based on canonical gene markers. ScRNA-seq generated 40,490 cells after filtering out low quality cells. We identified clusters of the following cell types (in descending order, based on proportionality): fibroblasts, which represented the largest portion of the cell population, followed by antigen-presenting cells, T cells, neuronal/glial cells including Schwann cells, vascular endothelial cells, lymphatic endothelial cells, keratinocytes, smooth muscle cells/pericytes, and melanocytes. Using the CellChat function, the most numerous cell-cell interactions occurred between fibroblasts and neuronal/glial cells, followed by fibroblasts and lymphatic endothelial cells. We identified 12 clusters of fibroblasts, and using markers of “cancer-associated fibroblasts” (CAFs) from prior literature of porcine plexiform neurofibromas containing the markers CXCL2, IL6, CCL2, and markers of other types of cancers, determined that four fibroblast clusters may contain CN-associated-CAFs, representing 32.2% of fibroblasts. We identified a subtype of CAF which showed highly enriched vascular endothelial growth factor (VEGF) related pathways, suggesting a potential pathway for targeting future therapies for CNs. Hannah Verma¹, Benjamin D. Hu¹, Jeremy Orloff¹, Carina Seah¹, Varun Subramaniam¹, Shaan Lalvani¹, O'Jay Stewart¹, Raphaella Lambert¹, Grace Rabinowitz¹, Swaroop Bose¹, Monali NandyMazumdar¹, Joel Correa da Rosa¹, Yeriel Estrada¹, Emma Guttman-Yassky¹, Andrew Ji¹, Rebecca Brown², Nicholas Gulati¹ 1. Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY, United States. 2. Neurology, University of Alabama at Birmingham, Birmingham, AL, United States. Bioinformatics, Computational Biology, and Imaging