A novel carboxamide bromodomain inhibitor attenuates osteoarthritis via epigenetic repression of NF-κB and MAPK signaling.

Hyemi Lee¹Seong Jae Han²Subin Ok¹Kwang Min Lee³Seungseok Choi¹Injoo Yoon¹Somang Choi¹Jina Kim⁴Serim Ryu⁵Min-Hee Son⁵In-Hyun Lee⁵Chanmi Cho⁶Siyoung Yang^1*

• ¹Sungkyunkwan University, Jongno-gu, Republic of Korea
• ²CentralBio Co., Std, Incheon, Republic of Korea
• ³Pusan National University, Miryang, Republic of Korea
• ⁴Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Republic of Korea
• ⁵Benobio Co., Std, Seongnam, Republic of Korea
• ⁶Massachusetts General Hospital Research Institute, Boston, United States

Thank you for your valuable comments in your response dated June 23, 2023. We have addressed all the reviewer concerns, and we would like to resubmit our manuscript titled "A novel carboxamide bromodomain inhibitor attenuates osteoarthritis via epigenetic repression of NF-κB and MAPK signaling." For publication as a Research Article in Frontiers in Immunology.In this revision, we have significantly improved the clarity and organization of the manuscript and further reinforced our study and explanation of the mechanistic framework. In particular, while chromatin immunoprecipitation (ChIP) assays were not performed in this study, we have strengthened our epigenetic interpretation by integrating high-throughput DNA-encoded library (DEL) screening data, which confirmed the selective and high-affinity binding of our compound, NCD, to BRD2 among BET family proteins. This DEL screening provides a solid biochemical basis supporting the specificity of NCD's epigenetic action and its role in regulating both the NF-κB and MAPK signaling pathways. These enhancements offer a more compelling mechanistic narrative, addressing prior limitations regarding target validation. In addition, we have included new in vivo histological analyses assessing liver and lung tissues following NCD treatment, which revealed no observable toxicity. While comprehensive hematological or neurobehavioral assessments were beyond the scope of this study, we have acknowledged this limitation and proposed future safety profiling to establish the translational feasibility of NCD. This manuscript has not been published previously and is not currently under consideration for publication in any other journal, either in part or in its entirety. We certify that all the authors have approved the submission of this manuscript. The animal study design was approved by the appropriate ethics review board. We have read and understood your journal's policies and believe that neither the manuscript nor the study violates any of them. We are grateful for your consideration of our paper and look forward to your response.Thank you for your consideration. We look forward to hearing from you.