Notch1和TLR4信号交互调控NF-kB活化和哮喘炎症的作用机制研究

Notch1 and TLR4 signaling pathway is well-known to be an important role in asthma. It has been reported TLR4 play a positive regulation role in Notch1 signal，and Hes1, a canonical Notch1 target and transcriptional repressor, is responsible for repressing the deubiquitinase CYLD to regulate TLR4-mediated NF-kB activation and inflammatory response. Our previous study showed LPS-induced Jagged1 and Notch1 expression were blocked by TLR4 inhibitor, and moreover, LPS-induced NF-kB activation and CYLD repression were enhanced by Jagged1 and blocked by an inhibitor of Notch 1 in RAW264.7 cells. In addition, the expression of Jagged1 and Hes1 were increased in lung tissue of asthmatic mice. In all of the research detailed evaluation of the mechanism of crosstalk between Notch1 and TLR4 signaling pathway on NF-kB activation and inflammatory response in asthma is still unclear. Here we use RAW264.7 cells and asthma model mice to investigate the effects of inhibitor of Notch1 and lentivirus vector-mediated Hes1 RNA interference on TLR4-mediated NF-kB activation, and elucidate the mechanism of crosstalk between Notch1 and TLR4 signaling pathway on NF-kB activation and inflammatory response in asthma. Furthermore, we will clarify the underlying feasibility of blocking Hes1 for treatment of asthma. Collectively, our study demonstrates that blocking Hes1 is a new vision and a new idea in prevention and treatment of asthma.

Notch1和TLR4信号在哮喘的发生和发展中发挥重要作用。研究表明，激活TLR4正性调控Notch1信号，同时Notch1通路激活产物Hes1能抑制CYLD表达，调控TLR4介导的NF-kB活化和炎症反应。我们前期研究发现：在RAW264.7中LPS提高Jagged1和Notch1表达但被TLR4抑制剂阻断，LPS诱导NF-kB活化和CYLD低表达能被Jagged1加强，但被Notch1抑制剂所阻断，哮喘小鼠肺组织内Jagged1和Hes1表达也明显增高。但Notch1和TLR4信号交互调控NF-kB活化和哮喘炎症的相关机制尚不清楚。本课题拟通过RAW264.7细胞和小鼠哮喘模型，从分子、细胞和整体水平明确Notch1和TLR4信号交互作用点，阐明Notch1和TLR4交互调控NF-kB活化和哮喘炎症的作用机制，探讨阻断Hes1治疗哮喘的可能性。为防治哮喘提供新的思路，开拓新的视野。

支气管哮喘是严重威胁人类生命健康的一种慢性炎症性疾病。随着社会经济的不断发展，哮喘发病率也逐年升高，全球总计约有3亿多哮喘患者，成为影响人们身心理健康的一种非常重要的疾病。目前哮喘的发病机制尚未彻底阐明，主要涉及免疫、神经、遗传和环境等诸多方面，其中哮喘与免疫学机制间的关系成为如今哮喘研究的重点。. Notch1和TLR4信号在哮喘的发生和发展中发挥重要作用。研究表明，激活TLR4正性调控Notch1信号，同时Notch1通路激活产物Hes1能抑制CYLD表达，调控TLR4介导的NF-kB活化和炎症反应，但Notch1和TLR4信号交互调控NF-kB活化和哮喘炎症的相关机制尚不清楚。本项目利用RAW264.7细胞和哮喘模型小鼠观察激活TLR4对Notch1信号的影响以及两者交叉对话对哮喘进程的影响。研究确认了在巨噬细胞中Notch1和TLR4信号之间存在交叉对话，LPS活化TLR4受体信号能够激活Notch1信号，提高Notch1，NICD和Hes1的表达，同时激活的Notch1信号通过调控CYLD参与TLR4信号介导MyD88/TRAF6共同激活IKK，随后激活IkB-a，NF-kB从胞浆进入细胞核，引起目的基因的转录。哮喘小鼠中通过药物调控Nocth1和TLR4的表达能明显抑制哮喘炎症。暗示Nocth1和TLR4信号在哮喘发病过程中发挥重要作用，从分子、细胞和整体水平明确Notch1和TLR4信号交互作用点，阐明Notch1和TLR4交互调控NF-kB活化和哮喘炎症的作用机制，探讨阻断Hes1治疗哮喘的可能性。为防治哮喘提供新的思路，开拓新的视野。