Effect of elastin peptides on ion fluxes in mononuclear cells, fibroblasts, and smooth muscle cells.

Abstract

Elastin peptides prepared by alcoholic potassium hydroxide degradation of highly purified fibrous elastin from bovine ligamentum nuchae (c-elastin) were shown to act on the ion channels of human monocytes, aorta smooth muscle cells, and skin fibroblasts. In small amounts (between 0.1 and 1 ,ug/ml), elastin peptides strongly increased calcium influx and inhibited calcium efflux by an apparently calmodulindependent mechanism. They also were shown to increase sodium influx and to decrease rubidium influx in monocyte preparations obtained from human blood. Only the ouabainsensitive portion of rubidium influx was inhibited. The action of elastin peptides is strongly concentration-dependent; the maximal activity observed in the above reactions was <1 /.g/ml. These results suggest that elastin peptides may play a role in the regulation of the biological activity of mesenchymal cells, in the proximity of which they are released by the action of elastase-type enzymes. Such enzymes were demonstrated in aorta smooth muscle cells (membrane-bound serine protease) and in fibroblasts (metalloprotease). Monocytes and polymorphonuclear leukocytes were also shown to carry elastase-type enzymes. The release of peptides from elastin by elastase-type enzymes and the action of such peptides on the ion fluxes through the cell membrane may well be involved in mechanisms of the modulation ofthe phenotype ofmesenchymal cells during aging as well as in the development of age-dependent pathologies such as arterioclerosis.The degradation of elastin by elastases was shown to play an important role in several pathological processes such as the development of emphysema (1-3), of atherosclerosis (4-6), and of a variety of skin diseases (7-9). This action was shown to be due to several proteases of the elastase type, that is, proteases that have an affinity for aliphatic amino acid sequences in hydrophobic proteins. Such enzymes have been described on the surface membrane of aorta smooth muscle cells (SMC) (10)(11)(12); in fibroblasts obtained from human skin, chicken embryo, pig aorta adventitia, and human vulva (13-15); and also in monocytes and macrophages (16). Platelets (17-19) and leukocytes (20, 21) also have been shown to carry a potent elastase-type protease.All of these enzymes, although of different nature (metalloprotease or seine protease), are able to attack elastin fibers and release soluble peptides. It also has been shown that soluble elastin peptides, such as a-elastin prepared by oxalic acid degradation (22) Here we report on the effect of elastin peptides on ion fluxes in fibroblasts and SMC as well as in human bloodderived mononuclear cells. MATERIALS AND METHODSPatients. Monocytes were obtained from 20 middle-aged healthy men (age 25-52 years) after informed consent. The selection of the subjects was based on the following criteria: good physical and mental health confirmed by clinical, radiological, and biological examinations.Monocytes were separated by Ficoll/Hypaque gradient centrifugation without any modificat...

Elastin Receptor (Spliced Galactosidase) Occupancy by Elastin Peptides Counteracts Proinflammatory Cytokine Expression in Lipopolysaccharide-Stimulated Human Monocytes through NF-κB Down-Regulation

“…Up to now, EPs were only involved in up-regulation of signaling cascade and gene expression (28,55,56). Thus, biological effects exerted by EPs should take into account the cell type used (37,57), the signaling pathway analyzed (31,56), and, as delineated in this study, the presence or not of coeffectors.…”

Inhibition of Matrix Metalloproteinase Activity Attenuates Tenascin-C Production and Calcification of Implanted Purified Elastin in Rats

“…44 This 67-kd elastin-binding receptor has been shown to be present on a variety of differentiated cells including chondrocytes, endothelial cells, vascular smooth muscle cells, fibroblasts, monocytes, and macrophages. [45][46][47][48][49] Activation of this receptor (because of elastin binding) triggers several cellular reactions such as modulation of the biosynthesis of connective tissue macromolecules, increase synthesis and release of protease including MMPs, modification of ion fluxes, and cell proliferation and apoptosis. 48 -51 Thus, in our elastin implants, it is possible that initial release of elastin peptides because of MMPs can trigger activation of this receptor on the fibroblasts and monocytes and cause several down-stream events including induction of MMPs and TN-C expression, as well as an increase in calcium ion fluxes within the cells.…”

Interaction between the Elastin Peptide VGVAPG and Human Elastin Binding Protein

“…Elastin peptide concentration in the blood flow is usually low, but it can reach high values in aged subjects, notably in those developing pathologies where elastin is massively degraded such as aneurysms (15,16). Unlike insoluble fibrous elastin, elastin peptides promote cell proliferation, cell chemotaxis, angiogenesis, and proteases release in a wide variety of normal cells (13,(17)(18)(19). The effects promoted by VGVAPG, a sequence repeated six times in human tropoelastin, are the most documented.…”