Single cell transcriptomic analyses of the developing meninges reveal meningeal fibroblast diversity and function

The meninges are a multilayered structure composed of fibroblasts, blood and lymphatic vessels, and immune cells. Meningeal fibroblasts secrete a variety of factors that control CNS development, yet strikingly little is known about their heterogeneity or development. Using single cell sequencing, we report distinct transcriptional signatures for fibroblasts in the embryonic dura, arachnoid and pial. We define new markers for meningeal layers and show conservation in human meninges. We find that embryonic meningeal fibroblasts are transcriptionally distinct between brain regions and identify a regionally localized pial sub-population marked by expression of µ-Crystallin. Developmental analysis reveals a progressive, ventral to dorsal maturation of telencephalic meninges. Our studies present an unprecedented view of meningeal fibroblasts, providing a molecular profile of embryonic meningeal fibroblasts by layer that yield insights into mechanisms of meninges development and function. Examination of gene transcripts of Collagen1-GFP (Col1a1-GFP) cells isolated from E14 forebrain mouse meninges using single cell RNA-sequencing