Degradation of decorin by matrix metalloproteinases: identification of the cleavage sites, kinetic analyses and transforming growth factor-β1 release

Abstract

Decorin (DCN) is a ubiquitous proteoglycan comprised of a core protein attached to a single dermatan/chondroitin sulphate glycosaminoglycan chain. It may play a role in regulation of collagen fibrillogenesis and function as a reservoir of transforming growth factor beta (TGF-beta) in the extracellular milieu. We have examined the susceptibility of DCN to five different matrix metalloproteinases (MMPs): MMP-1 (tissue collagenase), MMP-2 (gelatinase A), MMP-3 (stromelysin 1), MMP-7 (matrilysin) and MMP-9 (gelatinase B). MMP-2 and MMP-3 digest DCN into seven major fragments in a similar pattern. The N-terminal sequence of the two fragments generated by MMP-2 and MMP-3 is Leu211-Lys-Gly-Leu-Asn, but that of the others is Asp1-Glu-Ala-Ser-Gly. MMP-7 cleaves DCN into three major fragments which have the N-termini Asp1-Glu-Ala-Ser-Gly, Glu2-Ala-Ser-Gly-Ile and Leu244-His-Leu-Asp-Asn. Activities of MMP-1 and MMP-9 against DCN are negligible. The values of Km for the MMPs capable of degrading DCN are very similar (10-12 microM), but the kcat/Km value for MMP-7 (30.5 microM-1.h-1) is 4.5-fold higher than those for MMP-2 and MMP-3. Incubation of a DCN-TGF-beta1 complex with MMP-2, -3 or -7 results in release of TGF-beta1 from the complex. These data indicate proteolytic degradation of DCN by MMP-2, MMP-3 and MMP-7, and suggest the possibility that, under pathophysiological conditions, the digestion by the MMPs may induce tissue reactions mediated by TGF-beta1 released from DCN in the connective tissues.

The human RBPome: From genes and proteins to human disease

“…Genes that resulted in an index of 0.7 or higher were termed tissue-specific and the rest of them were classified as ubiquitous (Materials and Methods, Supplementary Table 4). The ubiquitous category ( Figure 4B shows selected set) comprised 40% of the RBP catalogue and included several well-known proteins such as the polypyimidine tract binding protein PTBP1 [56], polyadenylate binding nuclear protein PABPN1 [57], member of the 14-3-3 family YWHAE [58] and Decorin(DCN), a proteoglycan important in collagen fibrillogenesis [59]. In addition to these proteins, the ubiquitous category is highly enriched with the components of the spliceosome (SRSF9, SRSF2, U2AF1, HNRNPL) and proteasome (UBC, UBE2I, UBE2D3).…”

Dextran-shelled oxygen-loaded nanodroplets reestablish a normoxia-like pro-angiogenic phenotype and behavior in hypoxic human dermal microvascular endothelium

“…On the other hand, in chronic wounds, 532 reduced protein levels compared to acute wounds have been described for several growth 533 factors including FGF, EGF, PDGF, VEGF, and TGF-β, secondary to trapping by ECM 534 molecules or excessive degradation by MMPs [Greaves et al, 2013]. Importantly, many of 535 these growth factors are MMP-2 substrates, including TGF-β, released after decorin cleavage 536 [Cauwe et al, 2009;Imai et al, 1997]. 537…”

The possible role of matrix metalloproteinase (MMP)-2 and MMP-9 in cancer, e.g. acute leukemia

“…For example, degradation of laminin-5 (Ln-5) by MMP-2 results in the exposure of a Ln-5 cryptic site that enhances endothelial cell migration [2,92,96,97]. Besides degradation of ECM, MMPs are also capable of releasing growth factors from ECM and/or inactive complexes, cleaving growth factor receptors and activating growth factors excreted as pre-pro-enzymes, like transforming growth factor (TGF)-␣, TGF-␤, macrophage-colony stimulating factor (M-CSF), insulin like growth factor (IGF) and fibroblast growth factor receptor (FGFR)-1 [4,98,[98][99][100][101][102][103][104][105][106][107][108][109]. As pointed out, above MMPs can directly or indirectly induce tumor angiogenesis through degradation of ECM and release or activation of growth factors, like TNF-␣ and TGF-␤.…”