Single-cell ATAC-Seq of cells recruited to regenerative portions of large skin wounds.

Adult mammalian skin wound healing is typically accompanied by a fibrotic scar that impairs normal skin function and regeneration of skin appendages. Interestingly, however, in adult mice, large skin injuries exhibit de novo formation of hair follicles (HFs, a phenomenon termed wound-induced HF neogenesis) in the center of the wound. Our previous analysis provides compelling evidence suggesting that regional epigenetic changes within the mesenchymal cells of the skin may underlie the divergent response to wound healing. To test this directly, we performed single-cell Assay for Transposase-Accessible Chromatin using Sequencing (sc-ATAC-Seq) on cells isolated from the center of large wounds to identify regions of the genome that are becoming differentially accessible within upper (epithelial-interfacing) fibroblasts as they transition to induce new HFs compared to their lower dermal counterparts that adopt a fibrotic phenotype. Together, our data reveals the identity and dynamics of key coding, non-coding, and regulatory regions that underlie a wound responsive fibroblasts' transition to inductive neodermal condensate cells. To capture the epigenetic landscape of large wound center cells in an unbiased fashion, we profiled 1,578 single-cells using scATAC product from 10x Genomics. Next Generation Sequencing was performed at Genome Quebec using the Illumina HiSeq4000 platform.