Discovery and Characterization of a Novel Inhibitor of Matrix Metalloprotease-13 That Reduces Cartilage Damage in Vivo without Joint Fibroplasia Side Effects

Abstract

Matrix metalloproteinase-13 (MMP13) is a Zn2؉ -dependent protease that catalyzes the cleavage of type II collagen, the main structural protein in articular cartilage. Excess MMP13 activity causes cartilage degradation in osteoarthritis, making this protease an attractive therapeutic target. However, clinically tested MMP inhibitors have been associated with a painful, joint-stiffening musculoskeletal side effect that may be due to their lack of selectivity. In our efforts to develop a disease-modifying osteoarthritis drug, we have discovered MMP13 inhibitors that differ greatly from previous MMP inhibitors; they do not bind to the catalytic zinc ion, they are noncompetitive with respect to substrate binding, and they show extreme selectivity for inhibiting MMP13. By structurebased drug design, we generated an orally active MMP13 inhibitor that effectively reduces cartilage damage in vivo and does not induce joint fibroplasias in a rat model of musculoskeletal syndrome side effects. Thus, highly selective inhibition of MMP13 in patients may overcome the major safety and efficacy challenges that have limited previously tested non-selective MMP inhibitors. MMP13 inhibitors such as the ones described here will help further define the role of this protease in arthritis and other diseases and may soon lead to drugs that safely halt cartilage damage in patients.The National Institutes of Health has estimated that more than 20 million adults in the United States suffer from osteoarthritis (OA), 3 a debilitating disease in which the protective cushion of cartilage is destroyed, resulting in pain and reduced mobility. A critical step in OA pathology is breakdown of the main structural protein of articular cartilage, type II collagen. This triple helical protein is resistant to most proteases but is efficiently recognized and degraded by the Zn 2ϩ -dependent enzyme, collagenase-3, known as matrix metalloproteinase-13 (MMP13) (1-3). MMP13 catalyzes the hydrolysis of type II collagen at a unique site resulting in 3 ⁄4-and 1 ⁄4-length polypeptide products (2-6). MMP13 is not found in normal adult tissues but is expressed in the joints and articular cartilage of OA patients (4 -8). In addition, regulated expression of human MMP13 in hyaline and joint cartilages induces OA in genetically modified mice (9). Furthermore, a MMP inhibitor that preferentially inhibits MMP13 has been shown to block the degradation of explanted human osteoarthritic cartilage (5). Based on these findings, it is likely that MMP13 is the direct cause of irreversible cartilage damage in OA.The clinical development of drugs that inhibit the actions of MMPs has been plagued by the association of a painful, joint-stiffening tendonitis-like side effect, termed "musculoskeletal syndrome" (MSS), with these inhibitors (10, 11). Such joint side effects are not unique to humans. Rats dosed with non-selective MMP inhibitors (i.e. compounds that inhibit several or all MMPs) also display MSS-like side effects such as soft tissue fibroplasias, inflammation, and pain (...

A new class of potent matrix metalloproteinase 13 inhibitors for potential treatment of osteoarthritis: Evidence of histologic and clinical efficacy without musculoskeletal toxicity in rat models

“…In contrast, selectivity data on Ilomastat (Table 1) and other broad-spectrum inhibitors reported in the literature indicate that, although potent against MMP-13 activity, the broad-spectrum inhibitors lack selectivity (3,5,33,34). The only other MMP inhibitors with selectivity comparable with that of the MMP-13 inhibitors in the present study are the class of MMP-13 inhibitors recently reported in the literature (21). Steady-state kinetics and Lineweaver-Burk plot analysis of data on our MMP-13 inhibitor ALS 1-0635 demonstrated noncompetitive (mixed) inhibition.…”

“…Therefore, our strategy for development of DMOADs was to focus on identification of highly selective allosteric MMP-13 inhibitors free of hydroxamic acid or other zinc-chelating functional groups that contribute to inhibition of multiple MMPs. The rationale for targeting MMP-13 came from 1) overwhelming data on a potential role of MMP-13 in the pathogenesis of OA (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21), and 2) data from studies of MMP-13 knockout mice and humans with an MMP-13 mutation, suggesting lack of MSS liability (29)(30)(31)(32).…”

“…Moreover, semiselective MMP-13 inhibitors block degradation of human OA cartilage cultures (20). Recently, the chondroprotective effect of MMP-13-selective inhibitors was demonstrated in the rabbit surgical model of OA (21). Taken together, these data indicate that MMP-13 plays a pivotal role in the cartilage degradation observed in OA.…”

Dietary manipulation in musculoskeletal conditions

“…Zinc metalloenzymes such as MMPs are involved in the degradation of connective tissue and cartilage breakdown [86]. Copper on the other hand has a key role in building the extracellular matrix by cross-linking proteins such as collagen and elastin to give them structural integrity [87].…”

Strategic Targeting of Multiple Water‐Mediated Interactions: A Concise and Rational Structure‐Based Design Approach to Potent and Selective MMP‐13 Inhibitors

“…The overlay of PDB 2OW9 and PDB 2OZR10h indicated that on the right‐hand side, HOH747, HOH813 and HOH836 can be considered as structural water molecules that can be targeted as valuable binding partners in order to improve the binding affinity of phthalimide scaffold 4 . Compared with their counterparts in PDB 2OZR, those water molecules are located at very similar positions and share the same binding motifs to the target protein: HOH747 binds to the backbone NH of Leu 164, HOH813 binds to the carboxylate side chain of Glu 202, and HOH836 binds to the catalytic zinc ion as well as to the backbone carbonyl of Pro 221.…”