title: Overexpression of podocalyxin in megakaryocytes and platelets decreases the bleeding time and enhances the agonist-induced aggregation of platelets.
abstract: Podocalyxin (PODXL) is a 145KDa sialoprotein abundantly expressed in the glycocalix of the intraglomerular kidney epithelial cells, essential in maintaining a normal renal function. PODXL is also found in vascular endothelial cells, megakaryocytes and platelets. The function of PODXL in platelets is ignored; however, its surface exposure upon platelet activation suggests its participation in controlling the hemostasis. We have generated mice (pralphaIIb-PODXL) overexpressing PODXL specifically in megakaryocytes , either alone or as a fusion protein with green fluorescent protein. The transgenic mice showed a phenotype characterized by decreased bleeding time, mild rebleeding and enhanced platelets aggregation upon agonist stimulation. The cytohematological exams as well as the prothrombin time (PT) and (APTT) tests did not differ from the control group. The biochemical analysis showed only a discrete hyperlipemia and a rise in plasma uric acid levels in the transgenic mice. The present data seem to indicate that PODXL may act as a costimulator of agonists in the activation of platelets and formation of a stable thrombus.
authors.affiliation: Department of Physiopathology, Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu 9, 28040-Madrid, Spain.
authors.forename: Sonia
authors.initials: S
authors.lastname: Alonso-Martin
authors.forename: Adam
authors.initials: A
authors.lastname: Nowakowski
authors.forename: Susana
authors.initials: S
authors.lastname: Larrucea
authors.forename: Darío
authors.initials: D
authors.lastname: Fernández
authors.forename: Maripaz
authors.initials: M
authors.lastname: Vilar-Egea
authors.forename: Matilde S
authors.initials: MS
authors.lastname: Ayuso
authors.forename: Roberto
authors.initials: R
authors.lastname: Parrilla
mesh_terms: D000818:Animals; D001760:Bleeding Time; D001792:Blood Platelets / Q000378:metabolism* / Q000502:physiology; D006949:Hyperlipidemias; D008533:Megakaryocytes / Q000378:metabolism* / Q000502:physiology; D051379:Mice; D008817:Mice, Mutant Strains; D008822:Mice, Transgenic; D010974:Platelet Aggregation / Q000187:drug effects*; D012795:Sialoglycoproteins / Q000235:genetics / Q000494:pharmacology*; D014527:Uric Acid / Q000097:blood
chemical_list: D012795:Sialoglycoproteins; C001643:podocalyxin; D014527:Uric Acid