library_construction_protocol: Dura mater was peeled using forceps from calvaria and placed into a digestion solution (2.5 mg/ml collagenase IV in RPMI) and incubated for 20 min at 37°C shaking, after which the solution was filtered through 70 µm strainer (BD) and washed with FACS buffer. Sorted samples were processed using the 10X Chromium Next GEM Single Cell 3' Kit v3.1 (PN-1000269) and 3´ Feature Barcode Kit (PN-1000262). Single cell droplets were generated using Chromium Next GEM Chip G Single Cell Kit (PN-1000127) and Chromium Controller for 3' gene expression and cell multiplexing libraries were generated according to the manufacturer's specifications. Library quality was assessed using Agilent High Sensitivity DNA Kit (cat. no. 5067-4626). The single cell libraries were sequenced using Ilumina NovaSeq X Plus, with a minimum targeted sequencing depth of 20,000 reads per cell.