Polymorphonuclear leukocytes enhance release of growth factors by cultured endothelial cells.

Abstract

Porcine aortic endothelial cells (PAECs) in culture constitutivery secrete polypeptide (endothelium-derived) growth factors (EDGFs) into the surrounding medium. Incubation of PAECs with human peripheral blood polymorphonuclear leukocytes (PMNs) caused a significant increase in EDGF release as assessed by pH]thymidine incorporation into BALB/c 3T3 mouse fibroblasts and cell proliferation assay. The effect was time dependent and correlated with the number of PMNs, reaching a maximum with a 1:1 PAEC to PMN ratio. Generation of mitogenic activity was prevented by cycloheximide, indicating a requirement for de novo protein synthesis. Antibody-mediated inhibition assays suggested that mitogenic activity was due to platelet-derived growth factor and basic fibroblast growth factor. When supernatant from N-formyl-methionyl-leucyl-phenylalanine-stimulated PMNs was substituted for PMNs during incubation with PAECs, powerful mitogenic activity was generated, indicating the involvement of soluble mediators. A role for free oxygen radicals was ruled out by experiments in which superoxide dismutase and catalase did not prevent the increase in mitogenic activity. By contrast, serine protease inhibitors such as soybean trypsin inhibitor, a^antitrypsin, and eglin C reduced the PMN-stimulating activity by 70%, 80%, and 100%, respectively. The possible involvement of cathepsin G and elastase was investigated. Cathepsin G and elastase, when substituted for PMNs, increased the release of EDGFs in a dose-dependent fashion, mimicking the effect of PMNs. These findings suggest a new role for leukocyte-vessel wall interactions in the proliferative feature of atherosclerosis. (Arterioscler Thromb. 1994;14:125-132.)

Polymorphonuclear Leukocytes Induce PDGF Release From IL-1β–Treated Endothelial Cells

“…[43][44][45] We have recently shown that PMNs cultured in the presence of porcine aortic endothelial cells induce release of mitogenic activity whose nature is mostly attributable to PDGF and bFGF. 16 In the present study PDGF-AB antigen, detected in low concentrations in conditioned medium from PMN-or IL-1␤-treated HUVEC, was highly upregulated when both stimuli were present during incubation with HUVEC. This PDGF was active and responsible for the mitogenic activity, because a specific antibody, anti-PDGF-AB, almost completely inhibited the activity.…”

“…16 To exclude the possibility that the observed effect on the 3T3 cells could be due to the cooperation of IL-1␤ and components of conditioned medium, IL-1␤, at the maximal concentration used in our experiments, to postculture medium from HUVEC or HUVEC/PMN coincubation before the mitogenic assay was added. [ 3 H]-TdR incorporation into 3T3 cells induced by medium conditioned by HUVEC or HUVEC/PMN coincubation was not modified by IL-1␤ addition (not shown).…”

“…15 We have previously shown that serine proteases of PMN origin induce porcine aortic endothelial cells to synthesize and release platelet-derived growth factor (PDGF) and basic fibroblast growth factor (bFGF), 2 mitogens endowed with chemoattractant and mitogenic properties for mesenchymal-derived cells. 16 This observation suggests that PMN-endothelial cell interaction may contribute to pathogenesis of intimal proliferation in the vascular wall and to cell proliferation and tissue fibrosis, which accompany inflammatory diseases. In animal models in which vascular injury was induced by balloon angioplasty, perivascular manipulation, or electrical injury, an early wave of PMN adhesion and infiltration preceding smooth muscle cells proliferation was observed.…”

Expression of protease-activated receptors (PARs) in OLN-93 oligodendroglial cells and mechanism of PAR-1-induced calcium signaling

“…The statistical significance level for difference from control is given as: * Cathepsin G has been shown to have two apparently contradictory effects. In some cells that express thrombin receptors, including platelets (LaRosa et al, 1994;Molino et al, 1992) and porcine aortic endothelial cells (Totani et al, 1994), cathepsin G acts as an agonist causing [Ca 2ϩ ] i mobilization. In contrast, in human umbilical vein endothelial cells (Weksler et al, 1989) and fibroblasts (Selak, 1994) (Molino et al, 1995).…”

Protease activated receptors: theme and variations

“…Cathepsin G has di erent e ects on di erent cells, acting as an agonist in some cases and as a disabling protease in other (Selak et al, 1988;Molino et al, 1992;LaRosa et al, 1994;LeRoy et al, 1984;Totani et al, 1994). For example, cathepsin G causes an increase in cytosolic Ca 2+ in human platelets, but has no apparent agonist e ect on human endothelial cells or ®broblasts, despite the fact that PAR1 is present on all three.…”