Osteoarthritis (OA), the most common form of arthritis, is characterized by the destruction of articular cartilage. The main constituents of articular or joint cartilage are type II collagen and various proteoglycans, such as aggrecan, chondroitin sulfate, and hyaluronan. Matrix metalloproteinase 13 (MMP-13) has been shown to be main collagenase responsible for degradation of articular cartilage during OA. Multiple attempts to develop an MMP-13 inhibitor-based drug failed mostly due to the dose limiting side effects collectively known as musculoskeletal syndrome (MSS). While the exact cause of MSS is not known it is believed to be due to the lack of selectivity of drug candidates towards other representatives of metalloproteinase families. Identification of protease secondary binding sites (exosites), i.e. non-active site regions that facilitate or modulate protease activity, could be utilized for the design of selective inhibitors within protease families. Our laboratory has developed triple-helical peptide (THP) fluorescence resonance energy transfer (FRET) substrates for high throughput screening (HTS) of collagenolytic MMPs and identification of putative exosite-binding compounds. Using HTS techniques with FRET THP assays, we previously identified several selective low micromolar inhibitors of MMP-13. One inhibitor (compound Q/4, PubChem CID 2047223) exhibited properties suggesting that its mode of action was not via Zn chelation. Compound Q/4 possessed a significantly smaller molecular scaffold than previously described MMP-13 inhibitors, yet offered excellent selectivity. We wish to further develop compound Q/4 and its analogs as in vivo MMP-13 probes.
The specific aims to achieve this goal are as follows: (1) X-ray crystallography-guided medicinal chemistry of MMP-13 exosite probes;and (2) in vitro and in vivo testing of MMP-13 exosite probes. The present work will lead to in vivo probes that can evaluate the effects of selective inhibitors on extracellular proteolytic activity in OA and lay the groundwork for the development of novel MMP imaging agents. In addition, a unique mode of MMP inhibition will be identified.

Public Health Relevance

The active stage of osteoarthritis (OA) is characterized by the breakdown of articular cartilage collagen. The present research proposal advances new agents for analyzing enzymes that break down articular cartilage collagen in order to identify compounds that could be used as potential drug leads for developing novel anti-OA therapeutics.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
1R01AR063795-01A1
Application #
8631897
Study Section
Special Emphasis Panel (ZRG1-MDCN-C (58))
Program Officer
Tyree, Bernadette
Project Start
2013-09-17
Project End
2016-07-31
Budget Start
2013-09-17
Budget End
2014-07-31
Support Year
1
Fiscal Year
2013
Total Cost
$503,149
Indirect Cost
$114,307
Name
Torrey Pines Institute for Molecular Studies
Department
Type
DUNS #
605758754
City
Port Saint Lucie
State
FL
Country
United States
Zip Code
34987
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Stawikowski, Maciej J; Stawikowska, Roma; Fields, Gregg B (2015) Collagenolytic Matrix Metalloproteinase Activities toward Peptomeric Triple-Helical Substrates. Biochemistry 54:3110-21
Bhowmick, Manishabrata; Stawikowska, Roma; Tokmina-Roszyk, Dorota et al. (2015) Matrix metalloproteinase inhibition by heterotrimeric triple-helical Peptide transition state analogues. Chembiochem 16:1084-92
Fields, Gregg B (2015) New strategies for targeting matrix metalloproteinases. Matrix Biol 44-46:239-46
Fields, Gregg B (2014) Biophysical studies of matrix metalloproteinase/triple-helix complexes. Adv Protein Chem Struct Biol 97:37-48
Spicer, Timothy P; Jiang, Jianwen; Taylor, Alexander B et al. (2014) Characterization of selective exosite-binding inhibitors of matrix metalloproteinase 13 that prevent articular cartilage degradation in vitro. J Med Chem 57:9598-611