Cleavage of Cartilage Oligomeric Matrix Protein (COMP) by ADAMTS4 generates a neoepitope associated with osteoarthritis and other forms of degenerative joint disease.

Osteoarthritis (OA) is a highly prevalent joint disease, affecting millions of people worldwide and characterized by degradation of articular cartilage, subchondral bone remodeling and low-grade inflammation, leading to pain, stiffness and disability. Cartilage Oligomeric Matrix Protein (COMP) is a major structural component of cartilage and its degradation has been proposed as a marker of OA severity/progression. Several proteases cleave COMP in vitro, however, it is unclear which of these COMPase activities is prevalent in an osteoarthritic joint.

Soluble Proteoglycans and Proteoglycan Fragments as Biomarkers of Pathological Extracellular Matrix Remodeling.

Proteoglycans and their proteolytic fragments diffuse into biological fluids such as plasma, serum, urine, or synovial fluid, where they can be detected by antibodies or mass-spectrometry. Neopeptides generated by the proteolysis of proteoglycans are recognized by specific neoepitope antibodies and can act as a proxy for the activity of certain proteases. Proteoglycan and proteoglycan fragments can be potentially used as prognostic, diagnostic, or theragnostic biomarkers for several diseases characterized by dysregulated extracellular matrix remodeling such as osteoarthritis, rheumatoid arthritis, atherosclerosis, thoracic aortic aneurysms, central nervous system disorders, viral infections, and cancer.

Determination of Versikine Levels by Enzyme-Linked Immunosorbent Assay (ELISA).

The proteoglycan versican plays multiple roles in cancer progression, from promoting cell invasion and proliferation to evasion of immune surveillance. Metalloproteinases of the A Disintegrin and Metalloproteinase with Thrombospondin-like motif (ADAMTS) family cleave versican at a specific Glu-Ala bond, thus releasing a bioactive fragment named versikine, whose biological function, still not entirely revealed, seems that of antagonizing the effects of the parental molecule. Here we describe an enzyme-linked immunosorbent assay (ELISA) that specifically detects versikine in media, pure component systems, and biological fluids using neoepitope antibodies.

Expression and Purification of Recombinant ADAMTS8.

ADAMTS8 (A Disintegrin-like and Metalloproteinase with Thrombospondin motifs 8) is a secreted zinc-dependent metalloproteinase whose expression is downregulated in a variety of solid tumors. Xenografts expressing high levels of ADAMTS8 have a poor capacity to invade and migrate in nude mice. While this data highlights a beneficial, anti-cancerogenic role of ADAMTS8, the mechanism behind this activity is still not fully elucidated.

The C-terminal domains of ADAMTS1 contain exosites involved in its proteoglycanase activity.

A disintegrin-like and metalloproteinase with thrombospondin type 1 motifs (ADAMTS1) is a protease involved in fertilization, cancer, cardiovascular development, and thoracic aneurysms. Proteoglycans such as versican and aggrecan have been identified as ADAMTS1 substrates, and Adamts1 ablation in mice typically results in versican accumulation; however, previous qualitative studies have suggested that ADAMTS1 proteoglycanase activity is weaker than that of other family members such as ADAMTS4 and ADAMTS5. Here, we investigated the functional determinants of ADAMTS1 proteoglycanase activity.