Neuropilin-1 modulates interferon-γ-stimulated signaling in brain microvascular endothelial cells

Inflammatory response of blood-brain barrier (BBB) endothelial cells plays an important role in pathogenesis of many central nervous system inflammatory diseases, including multiple sclerosis (MS), however, the molecular mechanism mediating BBB endothelial cell inflammatory response remains unclear. In this study, we first observed that knockdown of neuropilin-1 (NRP1), a co-receptor of several structurally diverse ligands, suppressed interferon-γ (IFNγ) -induced C-X-C motif chemokine 10 expression and activation of STAT1 in brain microvascular endothelial cells in a Rac1 dependent manner. Moreover, endothelial specific NRP1 knockout mice, VECadherin-Cre-ERT2/NRP1flox/flox mice, showed attenuated disease progression during experimental autoimmune encephalomyelitis, a mouse neuroinflammatory disease model. Detailed analysis utilizing histological staining, quantitative PCR, flow cytometry, and magnetic resonance imaging demonstrated that deletion of endothelial NRP1 suppressed neuron demyelination, altered lymphocyte infiltration, preserved BBB function and decreased activation of STAT1-CXCL10 pathway. Furthermore, increased expression of NRP1 was observed in endothelial cells of acute MS lesions. Our data identified a novel molecular mechanism of brain microvascular endothelial inflammatory response through a NRP1–IFNγ crosstalk that could be a potential target for intervention of endothelial cell dysfunction in neuroinflammatory diseases.