Open Access Research

Biglycan fragmentation in pathologies associated with extracellular matrix remodeling by matrix metalloproteinases

Federica Genovese1*, Natasha Barascuk12, Lise Larsen1, Martin Røssel Larsen3, Arkadiusz Nawrocki3, Yili Li4, Qinlong Zheng4, Jianxia Wang4, Sanne Skovgård Veidal1, Diana Julie Leeming1 and Morten Asser Karsdal1

Author Affiliations

1 Nordic Bioscience A/S, Herlev Hovedgade 207, Herlev, DK-2730, Denmark

2 Department of Biochemistry and Genetics, Odense University Hospital, Sdr. Boulevard 29, Odense C, 5000, Denmark

3 Institute for Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, Odense, DK-5230, Denmark

4 Nordic Bioscience Beijing, Life park road 29, Zhongguancun Life Science Park, Beijing, Changoing district, 102206, China

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Fibrogenesis & Tissue Repair 2013, 6:9  doi:10.1186/1755-1536-6-9

Published: 1 May 2013

Abstract

Background

The proteoglycan biglycan (BGN) is involved in collagen fibril assembly and its fragmentation is likely to be associated with collagen turnover during the pathogenesis of diseases which involve dysregulated extracellular matrix remodeling (ECMR), such as rheumatoid arthritis (RA) and liver fibrosis. The scope of the present study was to develop a novel enzyme-linked immunosorbent assay (ELISA) for the measurement of a MMP-9 and MMP-12-generated biglycan neo-epitope and to test its biological validity in a rat model of RA and in two rat models of liver fibrosis, chosen as models of ECMR.

Results

Biglycan was cleaved in vitro by MMP-9 and -12 and the 344YWEVQPATFR353 peptide (BGM) was chosen as a potential neo-epitope. A technically sound competitive ELISA for the measurement of BGM was generated and the assay was validated in a bovine cartilage explant culture (BEX), in a collagen induced model of rheumatoid arthritis (CIA) and in two different rat models of liver fibrosis: the carbon tetrachloride (CCL4)-induced fibrosis model, and the bile duct ligation (BDL) model. Significant elevation in serum BGM was found in CIA rats compared to controls, in rats treated with CCL4 for 16 weeks and 20 weeks compared to the control groups as well as in all groups of rats subject to BDL compared with sham operated groups. Furthermore, there was a significant correlation of serum BGM levels with the extent of liver fibrosis determined by the Sirius red staining of liver sections in the CCL4 model.

Conclusion

We demonstrated that the specific tissue remodeling product of MMPs-degraded biglycan, namely the neo-epitope BGM, is correlated with pathological ECMR. This assay represents both a novel marker of ECM turnover and a potential new tool to elucidate biglycan role during the pathological processes associated with ECMR.

Keywords:
Biglycan; Biochemical markers; Extracellular matrix remodeling; Matrix-metalloproteinase; Neo-epitopes