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; 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 the STAT1–CXCL10 pathway. Furthermore, increased expression of NRP1 was observed in endothelial cells of acute multiple sclerosis lesions. Our data identify a new molecular mechanism of brain microvascular endothelial inflammatory response through NRP1–IFNγ crosstalk that could be a potential target for intervention of endothelial cell dysfunction in neuroinflammatory diseases.
The authors declare no competing or financial interests.
Y.W. performed in vitro experiments, BBB permeability assays, qPCR and western blotting analysis of animal tissues, and drafted the manuscript. Y.C. initiated this study and conducted the in vitro experiments. A.K.M. and B.D.C. performed EAE induction. Y.G. performed histological quantification and helped to optimize the staining protocol of human tissues. R.S.A. and B.D.C. conducted the flow cytometry analysis of spinal cords, and C.L.H. performed the analysis. J.D.G., P.A.A. and I.P. performed the mouse MRI analyses. Y.Z. conducted all the gavage feeding of tamoxifen. E.W. evaluated the EAE clinical scores and assisted Y.W. in animal breeding. R.S.A. assisted in the in vitro experiments. B.J. and K.D. helped with the analysis of reporter mice. A.K.M., C.L.H., B.J. and D.M. revised the manuscript. A.K.M., B.J., C.F.L., C.L.H. and D.M. helped to design the experiments and analyzed the results, and D.M. provided overall supervision of this project.
This work was supported by National Institutes of Health [grant numbers HL70567 and CA78383 to D.M.], Clinical and Translational Science Awards (CTSA) [grant numbers UL1 TR000135 and NIH K12 CA90628 to B.J.], Florida Department of Health Cancer Research Chair's Fund Florida [grant number 3J-02 to D.M.], and the American Heart Association [grant number AHA-14POST20390029 to Y.W.]. Deposited in PMC for release after 12 months.
Supplementary information available online at http://jcs.biologists.org/lookup/doi/10.1242/jcs.190702.supplemental
- Received April 13, 2016.
- Accepted August 31, 2016.
- © 2016. Published by The Company of Biologists Ltd