Production of vascular endothelial growth factors from human lung macrophages induced by group IIA and group X secreted phospholipases A2.
Angiogenesis and lymphangiogenesis mediated by vascular endothelial growth factors (VEGFs) are main features of chronic inflammation and tumors. Secreted phospholipases A(2) (sPLA(2)s) are overexpressed in inflammatory lung diseases and cancer and they activate inflammatory cells by enzymatic and receptor-mediated mechanisms. We investigated the effect of sPLA(2)s on the production of VEGFs from human macrophages purified from the lung tissue of patients undergoing thoracic surgery. Primary macrophages express VEGF-A, VEGF-B, VEGF-C, and VEGF-D at both mRNA and protein level. Two human sPLA(2)s (group IIA and group X) induced the expression and release of VEGF-A and VEGF-C from macrophages. Enzymatically-inactive sPLA(2)s were as effective as the active enzymes in inducing VEGF production. Me-Indoxam and RO092906A, two compounds that block receptor-mediated effects of sPLA(2)s, inhibited group X-induced release of VEGF-A. Inhibition of the MAPK p38 by SB203580 also reduced sPLA(2)-induced release of VEGF-A. Supernatants of group X-activated macrophages induced an angiogenic response in chorioallantoic membranes that was inhibited by Me-Indoxam. Stimulation of macrophages with group X sPLA(2) in the presence of adenosine analogs induced a synergistic increase of VEGF-A release and inhibited TNF-alpha production through a cooperation between A(2A) and A(3) receptors. These results demonstrate that sPLA(2)s induce production of VEGF-A and VEGF-C in human macrophages by a receptor-mediated mechanism independent from sPLA(2) catalytic activity. Thus, sPLA(2)s may play an important role in inflammatory and/or neoplastic angiogenesis and lymphangiogenesis.
Granata
Francescopaolo
F
Division of Clinical Immunology and Allergy and Center for Basic and Clinical Immunology Research, University of Naples Federico II, Naples.
Frattini
Annunziata
A
Loffredo
Stefania
S
Staiano
Rosaria I
RI
Petraroli
Angelica
A
Ribatti
Domenico
D
Oslund
Rob
R
Gelb
Michael H
MH
Lambeau
Gerard
G
Marone
Gianni
G
Triggiani
Massimo
M
D000818:Animals; D002384:Catalysis; D002642:Chick Embryo; D049033:Chorioallantoic Membrane / Q000098:blood supply / Q000201:enzymology / Q000378:metabolism; D054501:Group II Phospholipases A2 / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D054509:Group X Phospholipases A2 / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D018836:Inflammation Mediators / Q000502:physiology; D008168:Lung / Q000166:cytology / Q000201:enzymology* / Q000276:immunology* / Q000473:pathology; D042583:Lymphangiogenesis / Q000276:immunology; D016676:Macrophages, Alveolar / Q000166:cytology / Q000201:enzymology* / Q000276:immunology* / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000276:immunology; D020033:Protein Isoforms / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology; D043684:Receptor, Adenosine A3 / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology; D042582:Vascular Endothelial Growth Factor C / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology; D042442:Vascular Endothelial Growth Factors / Q000096:biosynthesis*
D018836:Inflammation Mediators; D020033:Protein Isoforms; D043684:Receptor, Adenosine A3; D042461:Vascular Endothelial Growth Factor A; D042582:Vascular Endothelial Growth Factor C; D042442:Vascular Endothelial Growth Factors; D054501:Group II Phospholipases A2; D054509:Group X Phospholipases A2