Application of SHP2 PROTAC to Mitigate Articular Cartilage Degeneration

点击翻译按钮获取中文摘要

PROJECT SUMMARY: It has been known for years that somatic SHP2 deletion in chondroid cells causes cartilage tumor formation associated with elevated SOX9 expression. However, it remains incompletely understood mechanistically how SHP2 depletion increases SOX9 and promotes chondroid cell proliferation. The work outlined in this proposal builds on our novel discovery that the genetic deletion of SHP2 in cartilage cells increases SOX9 abundance associated with SOX9 phosphorylation and sumoylation. These findings together stimulate the hypothesis that SHP2 physiologically limits SOX9 level in cartilage via posttranslational modifications. Therefore, intraarticular SHP2 depletion increases SOX9 protein abundance and transcriptional activity, promoting chondrocyte anabolism and protecting AC from injury-evoked degeneration. To test this novel hypothesis, we proposed two specific Aims. In Aim #1 we will determine to what extent intraarticular SHP2 degradation, using the first SHP2 PROTAC drug SHP2D26, mitigates injury-evoked articular cartilage degeneration. In Aim #2, we will interrogate the molecular mechanism through which SHP2 depletion enhances SOX9 abundance by focusing on SHP2’s regulation of SOX9 posttranslational modifications. This innovative study will result in the first-ever description of the mechanisms by which SHP2 modulates cartilage anabolism through SOX9 and provide instrumental information on the translational application of SHP2D26 in countering cartilage degeneration. Successful completion of the work proposed will have a significant impact on cartilage biology and OA prevention.