title: Podoplanin and CLEC-2 drive cerebrovascular patterning and integrity during development.
abstract: Mice with a constitutive or platelet-specific deletion of the C-type-lectin-like receptor (CLEC-2) exhibit hemorrhaging in the brain at mid-gestation. We sought to investigate the basis of this defect, hypothesizing that it is mediated by the loss of CLEC-2 activation by its endogenous ligand, podoplanin, which is expressed on the developing neural tube. To induce deletion of podoplanin at the 2-cell stage, we generated a podoplanin(fl/fl) mouse crossed to a PGK-Cre mouse. Using 3-dimensional light-sheet microscopy, we observed cerebral vessels were tortuous and aberrantly patterned at embryonic (E) day 10.5 in podoplanin- and CLEC-2-deficient mice, preceding the formation of large hemorrhages throughout the fore-, mid-, and hindbrain by E11.5. Immunofluorescence and electron microscopy revealed defective pericyte recruitment and misconnections between the endothelium of developing blood vessels and surrounding pericytes and neuro-epithelial cells. Nestin-Cre-driven deletion of podoplanin on neural progenitors also caused widespread cerebral hemorrhaging. Hemorrhaging was also seen in the ventricles of embryos deficient in the platelet integrin subunit glycoprotein IIb or in embryos in which platelet α-granule and dense granule secretion is abolished. We propose a novel role for podoplanin on the neuro-epithelium, which interacts with CLEC-2 on platelets, mediating platelet adhesion, aggregation, and secretion to guide the maturation and integrity of the developing vasculature and prevent hemorrhage.
authors.affiliation: Centre for Cardiovascular Sciences, Institute for Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom;
authors.forename: Kate L
authors.initials: KL
authors.lastname: Lowe
authors.affiliation: Centre for Cardiovascular Sciences, Institute for Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom;
authors.forename: Brenda A
authors.initials: BA
authors.lastname: Finney
authors.affiliation: Department of Experimental Biomedicine, University of Würzburg, University Hospital and Rudolf Virchow Centre, Würzburg, Germany;
authors.forename: Carsten
authors.initials: C
authors.lastname: Deppermann
authors.affiliation: Max-Planck-Institute for Molecular Biomedicine, Department Vascular Cell Biology, Münster, Germany;
authors.forename: René
authors.initials: R
authors.lastname: Hägerling
authors.affiliation: INSERM U970, Paris Cardiovascular Research Centre, Paris, France; Université Paris-Descartes, Paris, France;
authors.forename: Salomé L
authors.initials: SL
authors.lastname: Gazit
authors.affiliation: School of Immunity and Infection, and.
authors.forename: Jon
authors.initials: J
authors.lastname: Frampton
authors.affiliation: Rheumatology Research Group, Institute for Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Buckley
authors.affiliation: INSERM U970, Paris Cardiovascular Research Centre, Paris, France; Université Paris-Descartes, Paris, France;
authors.forename: Eric
authors.initials: E
authors.lastname: Camerer
authors.affiliation: Department of Experimental Biomedicine, University of Würzburg, University Hospital and Rudolf Virchow Centre, Würzburg, Germany;
authors.forename: Bernhard
authors.initials: B
authors.lastname: Nieswandt
authors.affiliation: Max-Planck-Institute for Molecular Biomedicine, Department Vascular Cell Biology, Münster, Germany;
authors.forename: Friedemann
authors.identifier: http://orcid.org/0000-0002-3002-8237
authors.initials: F
authors.lastname: Kiefer
authors.affiliation: Centre for Cardiovascular Sciences, Institute for Biomedical Research, College of Medical and Dental Sciences, University of Birmingham, Birmingham, United Kingdom;
authors.forename: Steve P
authors.initials: SP
authors.lastname: Watson
mesh_terms: D000818:Animals; D001792:Blood Platelets / Q000378:metabolism; D019521:Body Patterning; D001921:Brain / Q000098:blood supply* / Q000196:embryology* / Q000378:metabolism; D002560:Cerebrovascular Circulation; D017353:Gene Deletion; D018507:Gene Expression Regulation, Developmental; D020300:Intracranial Hemorrhages / Q000235:genetics / Q000378:metabolism; D037181:Lectins, C-Type / Q000235:genetics* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D008810:Mice, Inbred C57BL; D015539:Platelet Activation; D010974:Platelet Aggregation; D040201:Platelet Membrane Glycoprotein IIb / Q000235:genetics / Q000378:metabolism; D000098853:Podoplanin
chemical_list: D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D040201:Platelet Membrane Glycoprotein IIb; C529518:CLEC-2 protein, mouse; C490441:Pdpn protein, mouse; D000098853:Podoplanin