RNA Sequencing of sorted CD31+ meningeal endothelial cells from naïve Lewis rats

The meninges, comprising the leptomeninges (pia and arachnoid layers) and the pachymeninx (dura layer), participate in CNS autoimmunity but their relative contributions remain unclear. Here, we report on findings in animal models of CNS autoimmunity and in multiple sclerosis patients, where, in chronic disease, the leptomeninges were highly inflamed and showed structural changes, while the dura mater was only marginally affected. Although dural vessels were leakier than leptomeningeal vessels, effector T cells adhered more weakly to the dural endothelium. Furthermore, local antigen presenting cells presented myelin and neuronal autoantigens less efficiently and the activation of autoreactive T cells was lower in dural than leptomeningeal layers, preventing local inflammatory processes. Direct antigen application was required to evoke a local inflammatory response in the dura. Together, our data demonstrate an uneven involvement of the meningeal layers in CNS autoimmunity, in which effector T cell trafficking and activation are functionally confined to the leptomeninges, while the dura remains largely shielded from CNS autoimmune processes. Bulk RNA-Seq of CD31+ endothelial cells extracted from different brain meningeal compartments Brain meningeal tissues were harvested from naïve Lewis rats, endothelial cells extracted by digestion protocol and FACS sorted. Four animals were pooled for each tissue. The experiment was performed in 4 biological replicates.