KLHL5竞争性抑制KEAP1-CUL3泛素连接酶复合体与IKKβ互作在肠粘膜炎症损伤的作用和机制研究

已知KEAP1-CUL3 泛素化连接酶复合体通过 Kelch 结构域靶向 IKKβ 泛素化降解，可抑制 NF-κB 信号通路活化。然而，炎症性肠病（IBD）肠道炎症中 KEAP1-CUL3 泛素连接酶复合体抑炎效应并未明显呈现。我们的前期研究发现：①同属 KLHL蛋白家族的KLHL5在 IBD患者粘膜组织中表达上调，②体外研究证实其呈现正向调控NF-κB通路的促炎作用，③KLHL5 与 IKKβ 的 KD 结构域结合，抑制 KEAP1-CUL3复合体降解IKKβ泛素化的效应。故推测：KLHL5 拮抗 KEAP1-CUL3 泛素连接酶复合体降解IKKβ泛素化对NF-κB通路的负性调控效应，促IBD 肠道炎症损伤。本项目拟通过构建 KLHL5-/-转基因小鼠 DSS- 肠炎模型以及相应体外研究阐明 KLHL5 的促炎分子机制，探讨其潜在的可干预意义。项目的实施或为 IBD 的诊疗提供新思路。

KEAP1-CUL3 ubiquitin ligase complex has been demonstrated to regulate ubiquitination degradation of IKKβ through Kelch domain, thereby inhibiting NF-κB pathway activation. However, the anti-inflammatory effect of KEAP1-CUL3 ubiquitin ligase complex in inflammatory bowel disease (IBD) is not obvious. In our previous study, we found that KLHL5, another member of KLHL family, was upregulated in the mucosa of IBD patients, and played a pro-inflammatory role by activating NF-κB pathway in vitro. Further research suggested that KLHL5 bound to the KD domain of IKKβ and inhibited the KEAP1-CUL3 ubiquitin ligase complex mediated ubiquitination degradation of IKKβ. Therefore we proposed the hypothesis that KLHL5 antagonized KEAP1-CUL3 ubiquitin ligase complex mediated ubiquitination degradation of IKKβ，which positively regulated NF-κB pathway to promote intestinal inflammatory injury of IBD. This project intends to clarify the pro-inflammatory mechanism of KLHL5 by both in vivo and in vitro KLHL5-/- transgenic DSS mice model, aiming to provide further theoretical evidence and experimental foundation for novel treatment strategy of IBD.