T(H)17 lymphocytes appear to be essential in the pathogenesis of numerous inflammatory diseases. We demonstrate here the expression of IL-17 and IL-22 receptors on blood-brain barrier endothelial cells (BBB-ECs) in multiple sclerosis lesions, and show that IL-17 and IL-22 disrupt BBB tight junctions in vitro and in vivo. Furthermore, T(H)17 lymphocytes transmigrate efficiently across BBB-ECs, highly express granzyme B, kill human neurons and promote central nervous system inflammation through CD4+ lymphocyte recruitment.

The mammalian brain contains neurogenic niches comprising neural stem cells (NSCs) and other cell types. Neurogenic niches become less functional with age, but how they change during aging remains unclear. Here we perform single cell RNA-sequencing of young and old neurogenic Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the

Adhesion molecules of the immunoglobulin superfamily are crucial effectors of leukocyte trafficking into the central nervous system. Using a lipid raft-based proteomic approach, we identified ALCAM as an adhesion molecule involved in leukocyte migration across the blood-brain barrier (BBB). ALCAM expressed on BBB endothelium localized together with CD6 on leukocytes and with BBB endothelium transmigratory cups. ALCAM expression on BBB cells was upregulated in active multiple sclerosis and experimental autoimmune encephalomyelitis lesions. Moreover, ALCAM blockade restricted the transmigration of CD4+ lymphocytes and monocytes across BBB endothelium in vitro and in vivo and reduced the severity and delayed the time of onset of experimental autoimmune encephalomyelitis. Our findings indicate an important function for ALCAM in the recruitment of leukocytes into the brain and identify ALCAM as a potential target for the therapeutic dampening of neuroinflammation.