Boundary caps: a major source of skin mural cells

In the study we show that a specific peripheral glial population, derived from boundary cap (BC) cells, constitutes a major source of mural cells for the developing vasculature. Using Cre-based reporter cell tracing and single cell transcriptomics, we show that BC cell derivatives migrate along the nerves and differentiate into pericytes and vascular smooth muscle cells in the skin. The switch from glial to mural molecular identity is initiated while the cells are still associated with nerves To further characterize this transition glial to vascular identity, we performed single cell transcriptomic analyses (scRNA-seq) on FACS-purified traced cells from dissociated E12.5 skin. Tomato-positive cells were isolated by FACS from embryonic skin at E12.5. Around 10,000 cells were loaded into one channel of the Chromium system using the V3 single cell reagent kit (10X Genomics) We analyzed 2527 single cell transcriptomes with a mean number of expressed genes per cell of 4,696. This study highlights the plasticity of BC derivatives and uncovers a novel, nerve-derived origin for skin mural cells.