Action of Tropoelastin and Synthetic Elastin Sequences on Vascular Tone and on Free Ca ²⁺ Level in Human Vascular Endothelial Cells

Abstract

The elastic properties of extensible tissues such as arteries and skin are mainly due to the presence of elastic fibers whose major component is the extracellular matrix protein elastin. Pathophysiological degradation of this protein leads to the generation of elastin peptides that have been identified in the circulation in the ng/mL to microg/mL range. Similar concentrations of an elastin peptide preparation (kappa-elastin) were previously demonstrated to induce, among other biological actions, a dose- and endothelium-dependent vasorelaxation mediated by the elastin/laminin receptor and by endothelial NO production. To determine the elastin sequence(s) responsible for vasomotor activity and to learn more about possible signaling pathways, we have compared the action of different concentrations (10(-13) to 10(-7) mol/L) of recombinant human tropoelastin, eight synthetic elastin peptides, and a control peptide (VPVGGA) on both rat aortic ring tension and [Ca2+]i of cultured human umbilical vein endothelial cells. No vasoactivity could be detected for VPVGGA and for the elastin-related sequences VGVGVA, PGVGVA, and GVGVA. Tropoelastin, VGV, PGV, and VGVAPG were found to induce an endothelium- and dose-dependent vasorelaxation and to increase endothelial [Ca2+]i, whereas PVGV and VGVA produced these effects only at low concentration (10(-11) mol/L). A likely candidate for mediating the elastin peptide-related effects is the elastin/laminin receptor, since the presence of lactose strongly inhibited the vasoactivity associated with these compounds. Our results show that although the flanking amino acids modulate its activity, VGV seems to be the core sequence recognized by the elastin receptor.

Tropoelastin Enhances Nitric Oxide Production by Endothelial Cells

“…This effect diminished in response to treatment with laminin and lactose, which implicated the surface receptor, elastin binding protein which in turn leads to increased intracellular calcium [6]. Here, we show tropoelastin has a potent effect in inducing nitric oxide production by endothelial cells and that their exposure to tropoelastin leads to the activation of eNOS.…”

“…While cell signaling is directed by tropoelastin through cell-surface interactions [2], specific integrin binding sites have been recently identified in tropoelastin where they drive the attachment and proliferation of fibroblasts, endothelial and endothelial progenitor cells [3][4][5]. Also contained within the tropoelastin sequence are short repeating hydrophobic signaling motifs that are recognized by the elastin binding protein (EBP) and promote cellular chemotaxis and vasorelaxation [6].…”

Identification of a Novel Vasoconstrictor Peptide Specific for the Systemic Circulation

“…Indeed, other extracellular matrix-derived proteins, such as endostatin and elastin peptides, have been shown to be potent vasoactive compounds that not only affect vascularization but also vascular tone regulation. 12,13 In the present study we have, therefore, investigated the impact of the LNP CDPGYIGSR on vascular tone and found that it induced vasoconstriction in murine and human systemic but not pulmonary arteries. This effect was mediated by depolarization of vascular smooth muscle cells via nonselective cation channels (NSCCs) and transmembrane Ca 2ϩ influx through L-type Ca 2ϩ channels and could be also found in vivo.…”

Elastin Based Constructs

“…Synthetic peptides based on key elastin sequences present elastin-like properties including self-assembly, cross-linking and cell interactions (Long, King et al 1989;Faury, Garnier et al 1998;Bellingham, Woodhouse et al 2001;Karnik, Brooke et al 2003;Karnik, Wythe et al 2003). Coating of materials with elastin peptides can improve biocompatibility by providing protein sequences required for cell binding (reviewed by (Almine, Bax et al 2010)).…”