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TitlePodocalyxin is required for maintaining blood-brain barrier function during acute inflammation.
Publication TypeJournal Article
Year of Publication2019
AuthorsCait, Jessica, Michael R. Hughes, Matthew R. Zeglinski, Allen W. Chan, Sabrina Osterhof, Wilder R Scott, Diana Canals Hernaez, Alissa Cait, Wayne A Vogl, Pascal Bernatchez, Michael T Underhill, David J. Granville, Timothy H. Murphy, Calvin D. Roskelley, and Kelly M. McNagny
JournalProc Natl Acad Sci U S A
Date Published2019 Feb 20

Podocalyxin (Podxl) is broadly expressed on the luminal face of most blood vessels in adult vertebrates, yet its function on these cells is poorly defined. In the present study, we identified specific functions for Podxl in maintaining endothelial barrier function. Using electrical cell substrate impedance sensing and live imaging, we found that, in the absence of Podxl, human umbilical vein endothelial cells fail to form an efficient barrier when plated on several extracellular matrix substrates. In addition, these monolayers lack adherens junctions and focal adhesions and display a disorganized cortical actin cytoskeleton. Thus, Podxl has a key role in promoting the appropriate endothelial morphogenesis required to form functional barriers. This conclusion is further supported by analyses of mutant mice in which we conditionally deleted a floxed allele of in vascular endothelial cells (vECs) using Tie2Cre mice (). Although we did not detect substantially altered permeability in naïve mice, systemic priming with lipopolysaccharide (LPS) selectively disrupted the blood-brain barrier (BBB) in mice. To study the potential consequence of this BBB breach, we used a selective agonist (TFLLR-NH) of the protease-activated receptor-1 (PAR-1), a thrombin receptor expressed by vECs, neuronal cells, and glial cells. In response to systemic administration of TFLLR-NH, LPS-primed mice become completely immobilized for a 5-min period, coinciding with severely dampened neuroelectric activity. We conclude that Podxl expression by CNS tissue vECs is essential for BBB maintenance under inflammatory conditions.

Alternate JournalProc. Natl. Acad. Sci. U.S.A.
PubMed ID30787191
PubMed Central IDPMC6410846