Chemistry: molecular biology and microbiology – Measuring or testing process involving enzymes or... – Involving hydrolase
Reexamination Certificate
1998-07-24
2001-12-04
Achutamurthy, Ponnathapu (Department: 1652)
Chemistry: molecular biology and microbiology
Measuring or testing process involving enzymes or...
Involving hydrolase
C435S004000, C435S183000, C435S219000, C435S226000, C530S300000
Reexamination Certificate
active
06326162
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to various assays for determining aggrecanase or aggrecan degrading metallo protease (ADMP) activity. This invention also relates to a peptide that acts as a substrate for ADMPs, its use in various assays to determine the presence or absence of (ADMP) activity, and its use as an inhibitor of ADMP activity.
BACKGROUND OF THE INVENTION
Aggrecan is the major proteoglycan of cartilage and provides this tissue with its mechanical properties of compressibility and elasticity. In arthritic conditions one of the earliest changes observed in cartilage morphology is the depletion of aggrecan [Mankin et al. (1970) J. Bone Joint Surg. 52A, 424-434], which appears to be due to an increased rate of degradation.
The aggrecan molecule is composed of two N-terminal globular domains, G1 and G2, which are separated by an approximately 150 residue interglobular domain (IGD), followed by a long central glycosaminoglycan (GAG) attachment region and a C-terminal globular domain, G3 [Hardingham et al. (1992) in Articular Cartilage and Osteoarthritis: Aggrecan, The Chondroitin Sulfate/Keratan Sulfate Proteoglycan from Cartilage (Kuettner et al.) pp. 5-20, Raven Press, New York and Paulson et al. (1987) Biochem. J. 245, 763-772]. These aggrecan molecules interact through the G1 domain with hyaluronic acid and a link protein to form large molecular weight aggregates which are trapped within the cartilage matrix [Hardingham et al. (1972) Biochim. Biophys. Acta 279, 401-405, Heinegard et al. (1974) J. Biol. Chem. 249, 4250-4256, and Hardingham, T. E. (1979) Biochem. J. 177, 237-247]. Loss of aggrecan from cartilage in arthritic conditions involves proteolytic cleavage of the aggrecan core protein within the IGD, producing a N-terminal G-1 fragment that remains bound to hyaluronic acid and the link protein within the matrix, releasing a large C-terminal GAG-containing aggrecan fragment that diffuses out of the cartilage matrix. Loss of the C-terminal fragment results in cartilage deficient in its mechanical properties. This deficiency arises because the GAGs which are present on the C-terminal portion of the aggrecan core protein are the components of aggrecan that impart the mechanical properties to the molecule through their high negative charge and water binding capacity.
Two major sites of proteolytic cleavage have been identified within the IGD, one between amino acid residues Asn
341
-Phe
342
and the other between amino acid residues Glu
373
-Ala
374
(human sequence enumeration). Although G1 fragments formed by cleavage at the Asn
341
-Phe
342
site and at the Glu
373
-Ala
374
site have been identified within articular cartilage [Flannery et al. (1992) J. Biol. Chem. 267, 1008-1014], the only N-terminus identified on GAG-containing aggrecan C-terminal aggrecan fragments in synovial fluids of patients with osteoarthritis [Sandy et al. (1992) J. Clin. Invest. 69, 1512-1516], inflammatory joint disease [Lohmander et al. (1993) Arthritis Rheum. 36, 1214-1222] and in the media from cartilage explant and chondrocyte cultures stimulated with interleukin-1 or retinoic acid [Sandy et al. (1991) J. Biol. Chem. 266, 8198., Sandy et al. (1991) J. Biol. Chem. 266, 8683-8685., Leulakis et al. (1992) Biochem. J. 264, 589-593., Ilic et al. (1992) Arch. Biochem. Biophys. 294, 115-122., Lark et al. (1995) J. Biol. Chem. 270, 2550-2556. ] is ARGSVIL, indicating that they were formed by cleavage between amino acid residues Glu
373
-Ala
374
. These observations suggest that cleavage at this site may be responsible for cartilage degradation.
Although many matrix metalloproteases (MMP-1, -2, -3, -7, -8, -9 and 13) have been shown to cleave in vitro at the Asn
341
-Phe
342
site, digestion of aggrecan with a number of these purified proteases has not resulted in cleavage at the Glu
373
-Ala
374
site [Fosang et al. (1992) J. Biol. Chem. 267, 19470-19474., Flannery et al. (1992) J. Biol. Chem. 267, 1008-1014., Fosang et al. (1993) Biochem. J. 295, 273-276., Fosang et al. (1996) FEBS Lett. 380, 17-20., Flannery et al. (1993) Orthop. Trans. 17, 677., and Fosang et al. (1994) Biochem. J. 305, 347-351]. Therefore, cleavage at this site has been attributed to a novel, proteolytic activity, “aggrecanase”.
In addition to the Glu
373
-Ala
374
bond within the interglobular domain of aggrecan, four potential aggrecanase-sensitive sites have been identified within the C-terminus of the aggrecan core protein [Loulakis et al. (1992) Biochem. J. 264, 589-593. and Sandy et al. (1995) Acta Orhtop Scand (Suppl 266) 66, 26-32]. Although cleavage at these sites which are not within the interglobular domain would not be expected to release the major portion of the aggrecan molecule from the matrix, they may be involved in earlier processing of aggrecan within the matrix.
It follows from the foregoing considerations that a sensitive and specific assay that can detect such aggrecanase activity of aggrecan degrading metallo proteases (ADMPs) would be beneficial in helping to identify inhibitors of members of the ADMP family, which could serve as potential therapeutic agents for treating aggrecanase-related disorders cited above.
SUMMARY OF THE INVENTION
A preferred embodiment of the invention provides assays that determine the presence of aggrecan degrading metallo protease (ADMP) activity.
A preferred embodiment of the invention provides an assay using purified native aggrecan or recombinant aggrecan as the substrate and monitoring product generation via a direct enzyme-linked immunosorbent assay (ELISA) using neoepitope antibodies to detect the new N-terminus or new C-terminus on aggrecan fragments formed by specific cleavage at an ADMP-sensitive site in the aggrecan core protein.
A preferred embodiment of the invention provides peptides that have been found to act as substrates for the family of aggrecan degrading metallo proteases (ADMPs). One peptide, based on the human aggrecan sequence around the Ala373-Glu374 ADMP-sensitive site has the sequence:
QTVTWPDMELPLPRNITEGE-ARGSVILTVKPIFEVSPSPL (SEQ ID No:1)
A second peptide, based on the bovine aggrecan sequence around the Ala373-Glu374 ADMP-sensitive site has the sequence:
QTVTWPDVELPLPRNITEGE-ARGSVILTAKPDFEVSPTAPE (SEQ ID NO:2) Both peptides are capable of being cleaved at this specific recognition site by members of the family of ADMP proteins. A third peptide, based on the human aggrecan sequence around the Alal1714-Glyl1715 ADMP-sensitive site has the sequence:
ITFVDTSLVEVTPTTFKEEE-GLGSVELSGLPSGELGVSGT (SEQ ID NO:3)
and is capable of being cleaved at this specific recognition site by the family of ADMP proteins.
A preferred embodiment of the invention provides assay formats and methods of utilizing these peptide substrates for the detection and quantification of ADMP activity.
A preferred embodiment of the invention provides a modified version of the peptide substrates and a method for their use as an inhibitor of ADMP activity.
REFERENCES:
patent: 0785274 (1997-07-01), None
patent: 0785274A1 (1997-07-01), None
patent: 9322429 (1993-11-01), None
patent: 9601847 (1996-01-01), None
patent: 9725437 (1997-07-01), None
Mankin et al., 1970, J. Bone Joint Surg. 52A, 424-434.
Paulson et al. 1987, Biochem. J., 245, 763-772.
Hardingham et al. 1972, Biochem. Biophys. Acta, 279, 401-405.
Heinegard et al. 1974, J. Biol. Chem., 249, 4250-4256.
Hardingham, T. E., 1979, Biochem. J., 177, 237-247.
Flannery et al. 1992, J. Biol. Chem., 267, 1008-1014.
Sandy et al. 1992, J. Clin. Invest., 89, 1512-1516.
Lohmander et al. 1993, Arthritis Rheum., 36, 1214-1222.
Sandy et al. 1991, J. Biol. Chem. 266, 8198.
Sandy et. al. 1991, J. Biol. Chem. 266, 8683-8685.
Loulakis et al. 1992, Biochem. J., 284, 589-593.
Ilic et al. 1992, Arch. Biochem. Biophys., 294, 115-122.
Lark et al. 1995, J. Biol. Chem., 270, 2550-2556.
Fosang et al. 1992, J. Biol. Chem., 267, 19470-19474.
Fosang et al. 1993, Biochem J. 295, 273-276.
Fosang et al. 1996, FEBS Lett. 380, 17-20.
Flannery et al. 1993
Arner Elizabeth C.
Copeland Robert A.
Davis Gary L.
Liu Ruiqin
Miller Jeffrey A.
Achutamurthy Ponnathapu
Bristol-Myers Squibb Pharma Company
Fronda Christian L.
Fuzail Kalim S.
Konrad Karen
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