PDF(Pubmed)
Abstract：
Keap1 interacts with Nrf2 by assisting in its ubiquitination and subsequent proteolysis. By preventing ROS accumulation during RANKL-induced osteoclastogenesis, Nrf2 activation can prevent the differentiation of osteoclasts. Additionally, inhibiting the Keap1-Nrf2 PPI can be an effective strategy for triggering Nrf2 to regulate oxidative stress. Structure-based virtual screening was performed to discover a potentially novel Keap1-Nrf2 PPI inhibitor wherein KCB-F06 was identified. The inhibitory effects of KCB-F06 on osteoclastogenesis were investigated in vitro through TRAP staining and bone resorption assays. An ovariectomy-induced osteoporosis mouse model was applied to evaluate KCB-F06\'s therapeutic effects in vivo. Lastly, the underlying mechanisms were explored using real-time PCR, Western blotting, and co-IP assays. KCB-F06 was discovered as a novel Keap1-Nrf2 PPI inhibitor. As a result, the expression of antioxidants (HO-1 and NQO1) was suppressed, hence reducing ROS accumulation during osteoclastogenesis. Subsequently, this caused the inactivation of RANKL-induced IKB/NF-kB signaling. This eventually led to the downregulation of osteoclast-specific proteins including NFATc1, which is an essential transcription factor for osteoclastogenesis. These results demonstrated that Nrf2 activation in osteoclasts is a valuable tool for osteoclastic bone loss management. In addition, KCB-F06 presents as an alternative candidate for treating osteoclast-related bone diseases and as a novel small molecule that can serve as a model for further Keap1-NRF2 PPI inhibitor development.
摘要：
Keap1通过协助其泛素化和随后的蛋白水解与Nrf2相互作用。通过在RANKL诱导的破骨细胞形成过程中防止ROS积累，Nrf2激活可以阻止破骨细胞的分化。此外,抑制Keap1-Nrf2PPI可能是触发Nrf2调节氧化应激的有效策略。进行基于结构的虚拟筛选以发现潜在的新型Keap1-Nrf2PPI抑制剂,其中鉴定了KCB-F06。通过TRAP染色和骨吸收测定体外研究了KCB-F06对破骨细胞生成的抑制作用。采用卵巢切除诱导的骨质疏松小鼠模型评价KCB-F06的体内治疗效果。最后,使用实时PCR探索了潜在的机制，西方印迹,和co-IP测定。发现KCB-F06是一种新型Keap1-Nrf2PPI抑制剂。因此,抗氧化剂（HO-1和NQO1）的表达受到抑制，从而减少破骨细胞生成过程中的ROS积累。随后，这导致RANKL诱导的IKB/NF-kB信号的失活。这最终导致包括NFATc1在内的破骨细胞特异性蛋白的下调，NFATc1是破骨细胞生成的必需转录因子。这些结果表明，破骨细胞中的Nrf2激活是破骨细胞骨丢失管理的有价值的工具。此外,KCB-F06是治疗破骨细胞相关骨疾病的替代候选物，也是一种新型小分子，可作为进一步开发Keap1-NRF2PPI抑制剂的模型。
