title: Dysregulation of VEGF-induced proangiogenic Ca2+ oscillations in primary myelofibrosis-derived endothelial colony-forming cells.
abstract: Endothelial progenitor cells could be implicated in the aberrant neoangiogenesis that occurs in bone marrow and spleen in patients with primary myelofibrosis (PMF). However, antivascular endothelial growth factor (VEGF) monotherapy had only a modest and transient effect in these individuals. Recently it was found that VEGF-induced proangiogenic intracellular Ca(2+) oscillations could be impaired in endothelial progenitor cells of subjects with malignancies. Therefore, we employed Ca(2+) imaging, wavelet analysis, and functional assays to assess whether and how VEGF-induced Ca(2+) oscillations are altered in PMF-derived endothelial progenitor cells. We focused on endothelial colony-forming cells (ECFCs), which are the only endothelial progenitor cell subtype capable of forming neovessels both in vivo and in vitro. VEGF triggers repetitive Ca(2+) spikes in both normal ECFCs (N-ECFCs) and ECFCs obtained from PMF patients (PMF-ECFCs). However, the spiking response to VEGF is significantly weaker in PMF-ECFCs. VEGF-elicited Ca(2+) oscillations are patterned by the interaction between inositol-1,4,5-trisphosphate-dependent Ca(2+) mobilization and store-operated Ca(2+) entry. However, in most PMF-ECFCs, Ca(2+) oscillations are triggered by a store-independent Ca(2+) entry pathway. We found that diacylglycerol gates transient receptor potential canonical 1 channel to trigger VEGF-dependent Ca(2+) spikes by recruiting the phospholipase C/inositol-1,4,5-trisphosphate signaling pathway, reflected as a decrease in endoplasmic reticulum Ca(2+) content. Finally, we found that, apart from being less robust and dysregulated as compared with N-ECFCs, VEGF-induced Ca(2+) oscillations modestly stimulate PMF-ECFC growth and in vitro angiogenesis. These results may explain the modest effect of anti-VEGF therapies in PMF.
authors.affiliation: Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Dragoni
authors.affiliation: Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Marta
authors.initials: M
authors.lastname: Reforgiato
authors.affiliation: Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Estella
authors.initials: E
authors.lastname: Zuccolo
authors.affiliation: Center for the Study of Myelofibrosis, Research Laboratory of Biotechnology, IRCCS Policlinico San Matteo Foundation, Pavia, Italy.
authors.forename: Valentina
authors.initials: V
authors.lastname: Poletto
authors.affiliation: Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Lodola
authors.affiliation: Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy.
authors.forename: Federico Alessandro
authors.initials: FA
authors.lastname: Ruffinatti
authors.affiliation: Center for the Study of Myelofibrosis, Research Laboratory of Biotechnology, IRCCS Policlinico San Matteo Foundation, Pavia, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Bonetti
authors.affiliation: Department of Medicine and Health Sciences "Vincenzo Tiberio" Health Sciences, University of Molise, Campobasso, Italy.
authors.forename: Germano
authors.initials: G
authors.lastname: Guerra
authors.affiliation: Center for the Study of Myelofibrosis, Research Laboratory of Biotechnology, IRCCS Policlinico San Matteo Foundation, Pavia, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Barosi
authors.affiliation: Center for the Study of Myelofibrosis, Research Laboratory of Biotechnology, IRCCS Policlinico San Matteo Foundation, Pavia, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Rosti
authors.affiliation: Laboratory of General Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy. Electronic address: francesco.moccia@unipv.it.
authors.forename: Francesco
authors.initials: F
authors.lastname: Moccia
mesh_terms: D020013:Calcium Signaling; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D055728:Primary Myelofibrosis / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D013234:Stem Cells / Q000378:metabolism* / Q000473:pathology; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*
chemical_list: C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A