Matriptase Induction of Metalloproteinase-Dependent Aggrecanolysis In Vitro and In Vivo: Promotion of Osteoarthritic Cartilage Damage by Multiple Mechanisms.

David J Wilkinson,Antoine Désilets,Charles S Craik,Jennifer M Milner,Alastair R Hawkins,Heather K Lamb,Melody S Lee,Angela Habgood,Paul Thompson,Maya Hammami,Sharon Watson,Andrew D Rowan,Richard Leduc,Hua Lin,Torsten Steinmetzer

doi:10.1002/art.40133

Abstract

ObjectiveTo assess the ability of matriptase, a type II transmembrane serine proteinase, to promote aggrecan loss from the cartilage of patients with osteoarthritis (OA) and to determine whether its inhibition can prevent aggrecan loss and cartilage damage in experimental OA.MethodsAggrecan release from human OA cartilage explants and human stem cell–derived cartilage discs was evaluated, and cartilage‐conditioned media were used for Western blotting. Gene expression was analyzed by real‐time polymerase chain reaction. Murine OA was induced by surgical destabilization of the medial meniscus, and matriptase inhibitors were administered via osmotic minipump or intraarticular injection. Cartilage damage was scored histologically and aggrecan cleavage was visualized immunohistochemically using specific neoepitope antibodies.ResultsThe addition of soluble recombinant matriptase promoted a time‐dependent release of aggrecan (and collagen) from OA cartilage, which was sensitive to metalloproteinase inhibition and protease‐activated receptor 2 antagonism. Although engineered human (normal) cartilage discs failed to release aggrecan following matriptase addition, both matrix metalloproteinase– and aggrecanase‐mediated cleavages of aggrecan were detected in human OA cartilage. Additionally, while matriptase did not directly degrade aggrecan, it promoted the accumulation of low‐density lipoprotein receptor–related protein 1 (LRP‐1) in conditioned media of the OA cartilage explants. Matriptase inhibition via neutralizing antibody or small molecule inhibitor significantly reduced cartilage damage scores in murine OA, which was associated with reduced generation of metalloproteinase‐mediated aggrecan cleavage.ConclusionMatriptase potently induces the release of metalloproteinase‐generated aggrecan fragments as well as soluble LRP‐1 from OA cartilage. Therapeutic targeting of matriptase proteolytic activity reduces metalloproteinase activity, further suggesting that this serine proteinase may have potential as a disease‐modifying therapy in OA.

Highlights

While matriptase did not directly degrade aggrecan, it promoted the accumulation of low-density lipoprotein receptor–related protein 1 (LRP-1) in conditioned media of the OA cartilage explants
Recent findings confirm the high mechanosensitivity proteinase genes which are rapidly expressed following induction of experimental OA [15], and our own previous data confirmed elevated expression of both matriptase and protease-activated receptor 2 (PAR-2) following destabilization of the medial meniscus (DMM) [10]. These findings suggest that targeting PAR-2 activators, rather than PAR-2 directly, will help provide specificity and could have potential as a disease-modifying OA drug (DMOAD)
Addition of recombinant matriptase to human OA cartilage in ex vivo culture over a 14-day period resulted in a time-dependent release of collagen, as previously reported [10], unlike the findings obtained with the potent pro-catabolic stimulus IL-1 plus Oncostatin M (OSM) (Figure 1A)

Summary

Introduction

VC 2017 The Authors. Arthritis & Rheumatology published by Wiley Periodicals, Inc. on behalf of American College of Rheumatology. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. David J. Wilkinson,1 Angela Habgood,1 Heather K. Lamb,1 Paul Thompson,1 Alastair R. Hawkins,1 Antoine Desilets,2 Richard Leduc,2 Torsten Steinmetzer,3 Maya Hammami,3 Melody S. Lee,4 Charles S. Craik,4 Sharon Watson,1 Hua Lin,1

Methods

Results

Discussion

Conclusion