The binding of elastin peptides on the elastin receptor complex leads to the formation of intracellular signals but how this is achieved remains totally unknown. Using pharmacological inhibitors of the enzymatic activities of its subunits, we show here that the elastin peptide-driven ERK1/2 activation and subsequent pro-MMP-1 production, observed in skin fibroblasts when they are cultured in the presence of these peptides, rely on a membrane-bound sialidase activity. As lactose blocked this effect, the elastin receptor sialidase subunit, Neu-1, seemed to be involved. The use of a catalytically inactive form of Neu-1 and the small interfering RNA-mediated decrease of Neu-1 expression strongly support this view. Finally, we report that N-acetyl neuraminic acid can reproduce the effects of elastin peptides on both ERK1/2 activation and pro-MMP-1 production. Altogether, our results indicate that the enzymatic activity of the Neu-1 subunit of the elastin receptor complex is responsible for its signal transduction, presumably through sialic acid generation from undetermined substrates.Elastin is the extracellular matrix protein responsible for the elasticity of tissues. It is more abundant in tissues where resilience is required, such as skin, lung, ligaments, or large arteries (1). Elastin is constituted of tropoelastin molecules covalently bound to each other by covalent cross-links (2) and its hydrophobic and highly cross-linked nature make of it a very durable polymer experiencing essentially no turnover in healthy tissues (3).The biological role of elastin was originally thought to be restricted to this mechanical function. However, when Senior et al. (4) demonstrated that elastin digestion products were chemotactic for neutrophils and macrophages, it became suddenly apparent that peptides derived from amorphous elastin could modulate cell physiology. In fact, it has been shown because that fibroblasts (5-12), smooth muscle cells (7, 13-15), endothelial cells (16 -19), leukocytes (20, 21), and lymphocytes (22) were sensitive to the presence of these peptides yielding a broad range of biological activities (see Ref. 23 for a review). A corollary of these observations was that those cells do express a receptor for elastin peptides.The elastin receptor complex is constituted of three subunits, one peripheral 67-kDa subunit, which actually binds elastin, and two membrane-associated proteins of 61 and 55 kDa, respectively (10). The 67-kDa elastin-binding protein (EBP) 2 binds the VGVAPG elastin sequence with high affinity. Additionally, EBP can be eluted from elastin affinity column by galactosugars suggesting that the elastin-EBP interaction could be regulated by galactosugars bound on a lectin site on EBP (10, 24). Consequently, galactosugars such as lactose are commonly used antagonists of EBP.Later, the nature of this subunit was revealed by the work of Privitera et al. (25) who have shown that EBP is an enzymatically spliced variant of lysosomal ␤-galactosidase (␤-Gal, EC 3.2.1.23). Consequently, it was hypot...

Background:The interaction of the peptide VGVAPG with the elastin binding protein is critically involved in aneurysm progression.Results: A molecular model of this interaction is proposed and explored using a site-directed mutagenesis strategy. Conclusion: Three residues, Leu-103, Arg-107, and Glu-137, of elastin binding protein are critical players in this interaction. Significance: Our data now allow the design of antagonists of VGVAPG.

Background:Elastin peptides possess several biological activities and in vitro data suggest they could be involved in the early phase of melanoma growth.Methods:Using diverse in vitro and in vivo techniques (cell proliferation, invasion and migration assays, zymography, western blots, collagen degradation assay, reverse transcription PCR, melanoma allographs and immunohistochemistry), we analysed the effect of elastin-derived peptides (EDPs) on B16F1 melanoma growth and invasion, as well as on the proteolytic systems involved.Results:We found that EDPs dramatically promote in vivo tumour development of B16F1 melanoma, as well as their in vitro migration and invasion. The inhibition of serine proteases and matrix metalloproteinases (MMPs) activities, by aprotinin and galardin, respectively, demonstrated that these enzymes were involved in these processes. However, we found that EDPs did not increase urokinase-type plasminogen activator, tissue-type plasminogen activator or MMP-2 expression and/or activation, neither in vitro nor in vivo. Nevertheless, we observed a strong increase of pro-MMP-9 secretion in EDPs-treated tumours and, more importantly, an increase in the expression and activation of the murine counterpart of MMP-1, named murine collagenase-A (Mcol-A). Moreover, we show that plasminogen system inhibition decreases collagen degradation by this enzyme. Finally, the use of a specific blocking antibody against Mcol-A abolished EDP-induced B16F1 invasion in vitro, showing that this MMP was directly involved in this process.Conclusion:Our data show that in vivo, EDPs are involved in melanoma growth and invasion and reinforced the concept of elastin fragmentation as a predictive factor.