title: New insights into the substrate specificity of macrophage elastase MMP-12.
abstract: Macrophage elastase, or MMP-12, is mainly produced by alveolar macrophages and is believed to play a major role in the development of chronic obstructive pulmonary disease (COPD). The catalytic domain of MMP-12 is unique among MMPs in that it is very highly active on numerous substrates including elastin. However, measuring MMP-12 activity in biological fluids has been hampered by the lack of highly selective substrates. We therefore synthesized four series of fluorogenic peptide substrates based on the sequences of MMP-12 cleavage sites in its known substrates. Human MMP-12 efficiently cleaved peptide substrates containing a Pro at P3 in the sequence Pro-X-X↓Leu but lacked selectivity towards these substrates compared to other MMPs, including MMP-2, MMP-7, MMP-9 and MMP-13. On the contrary, the substrate Abz-RNALAVERTAS-EDDnp derived from the CXCR5 chemokine was the most selective substrate for MMP-12 ever reported. All substrates were cleaved more efficiently by full-length MMP-12 than by its catalytic domain alone, indicating that the C-terminal hemopexin domain influences substrate binding and/or catalysis. Docking experiments revealed unexpected interactions between the peptide substrate Abz-RNALAVERTAS-EDDn and MMP-12 residues. Most of our substrates were poorly cleaved by murine MMP-12 suggesting that human and murine MMP-12 have different substrate specificities despite their structural similarity.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Lamort
authors.forename: Rodolphe
authors.initials: R
authors.lastname: Gravier
authors.forename: Anni
authors.initials: A
authors.lastname: Laffitte
authors.forename: Luiz
authors.initials: L
authors.lastname: Juliano
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Zani
authors.forename: Thierry
authors.initials: T
authors.lastname: Moreau
mesh_terms: D000818:Animals; D055162:Biocatalysis; D020134:Catalytic Domain; D005456:Fluorescent Dyes / Q000737:chemistry*; D006801:Humans; D053508:Matrix Metalloproteinase 12 / Q000737:chemistry*; D051379:Mice; D062105:Molecular Docking Simulation; D009842:Oligopeptides / Q000737:chemistry*; D013045:Species Specificity; D013379:Substrate Specificity
chemical_list: D005456:Fluorescent Dyes; D009842:Oligopeptides; D053508:Matrix Metalloproteinase 12