title: IFN-β affects the angiogenic potential of circulating angiogenic cells by activating calpain 1.
abstract: Circulating angiogenic cells (CACs) are monocyte-derived cells with endothelial characteristics, which contribute to both angiogenesis and arteriogenesis in a paracrine way. Interferon-β (IFN-β) is known to inhibit these divergent processes in animals and patients. We hypothesized that IFN-β might act by affecting the differentiation and function of CACs. CACs were cultured from peripheral blood mononuclear cells and phenotypically characterized by surface expression of monocytic and endothelial markers. IFN-β significantly reduced the number of CACs by 18-64%. Apoptosis was not induced by IFN-β, neither in mononuclear cells during differentiation, nor after maturation to CACs. Rather, IFN-β impaired adhesion to, and spreading on, fibronectin, which was dependent on α5β1 (VLA-5)-integrin. IFN-β affected the function of VLA-5 in mature CACs, leading to rounding and detachment of cells, by induction of calpain 1 activity. Cell rounding and detachment was completely reversed by inhibition of calpain 1 activity in mature CACs. During in vitro capillary formation, CAC addition and calpain 1 inhibition enhanced sprouting of endothelial cells to a comparable extent, but were not sufficient to rescue tube formation in the presence of IFN-β. We show that the IFN-β-induced reduction of the numbers of in vitro differentiated CACs is based on activation of calpain 1, resulting in an attenuated adhesion to extracellular matrix proteins via VLA-5. In vivo, this could lead to inhibition of vessel formation due to reduction of the locally recruited CAC numbers and their paracrine angiogenic factors.
authors.affiliation: Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands;
authors.forename: Cansu
authors.initials: C
authors.lastname: Yıldırım
authors.affiliation: Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands;
authors.forename: Julie
authors.initials: J
authors.lastname: Favre
authors.affiliation: Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands; and.
authors.forename: Ester M
authors.initials: EM
authors.lastname: Weijers
authors.affiliation: Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands;
authors.forename: Ruud D
authors.initials: RD
authors.lastname: Fontijn
authors.affiliation: Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands; and.
authors.forename: Michiel H
authors.initials: MH
authors.lastname: van Wijhe
authors.affiliation: Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands;
authors.forename: Sandra J
authors.initials: SJ
authors.lastname: van Vliet
authors.affiliation: Institute for Cardiovascular Regeneration, Centre for Molecular Medicine, Goethe University, Frankfurt, Germany.
authors.forename: Reinier A
authors.initials: RA
authors.lastname: Boon
authors.affiliation: Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands; and.
authors.forename: Pieter
authors.initials: P
authors.lastname: Koolwijk
authors.affiliation: Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands;
authors.forename: Tineke C T M
authors.initials: TC
authors.lastname: van der Pouw Kraan
authors.affiliation: Department of Molecular Cell Biology and Immunology, VU University Medical Center, Amsterdam, The Netherlands; aj.horrevoets@vumc.nl.
authors.forename: Anton J G
authors.initials: AJ
authors.lastname: Horrevoets
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002154:Calpain / Q000187:drug effects* / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects*; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D005353:Fibronectins; D006801:Humans; D066298:In Vitro Techniques; D039081:Integrin alpha5beta1 / Q000187:drug effects / Q000378:metabolism; D016899:Interferon-beta / Q000494:pharmacology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology
chemical_list: D005353:Fibronectins; D039081:Integrin alpha5beta1; D016899:Interferon-beta; D002154:Calpain; C484806:CAPN1 protein, human
keywords: angiogenesis; calpain 1 inhibitor; circulating angiogenic cells; sprouting