New probes for matrix metalloproteinase 13

描述(申请人提供)：骨关节炎(OA)是最常见的关节炎形式，其特征是关节软骨遭到破坏。关节或关节软骨的主要成分是II型胶原和各种蛋白多糖，如胶聚糖、硫酸软骨素和透明质酸。基质金属蛋白酶13(MMP13)是骨性关节炎关节软骨降解的主要胶原酶。开发基于基质金属蛋白酶-13抑制剂的药物的多次尝试都失败了，主要是由于剂量限制的副作用，统称为肌肉骨骼综合征(MSS)。虽然MSS的确切原因尚不清楚，但它被认为是由于候选药物缺乏对其他金属蛋白酶家族代表的选择性。鉴定蛋白水解酶二级结合位点(外显子)，即促进或调节蛋白水解酶活性的非活性位点区域，可用于设计蛋白水解酶家族中的选择性抑制剂。我们实验室已经开发了三螺旋多肽(THP)荧光共振能量转移(FRET)底物，用于高通量筛选(HTS)胶原酶降解MMPs和鉴定可能的胞外结合化合物。使用HTS技术和FRET THP分析，我们先前发现了几种选择性的低微摩尔的基质金属蛋白酶-13抑制剂。一种抑制剂(化合物Q/4，PubChem CID 2047223)的性质表明其作用模式不是通过锌螯合。化合物Q/4的分子支架比之前描述的基质金属蛋白酶-13抑制剂要小得多，但提供了良好的选择性。我们希望进一步开发化合物Q/4及其类似物作为体内的基质金属蛋白酶-13探针。实现这一目标的具体目标如下：(1)X射线晶体学指导下的基质金属蛋白酶-13胞外探针的药物化学；(2)体外和体内检测基质金属蛋白酶-13胞外探针。本工作将为体内评价选择性抑制剂对骨性关节炎细胞外蛋白水解酶活性的影响奠定基础，并为新型基质金属蛋白酶显像剂的开发奠定基础。此外，还将确定一种独特的抑制基质金属蛋白酶的模式。

DESCRIPTION (provided by applicant): 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.