Cbl-b/C-Cbl 双敲单核巨噬细胞在特发性肺纤维化发生发展中的作用及机制研究

特发性肺纤维化是一种慢性、进行性、纤维化性间质性肺疾病，巨噬细胞导致的炎症在IPF发生发展中的作用越来越得到肯定，但何种原因引起了巨噬细胞的活化尚不甚清楚。在单核/巨噬细胞中我们同时敲除E3泛素化连接酶Cbl-b/C-Cbl后，发现小鼠在35天左右出现典型的以成熟巨噬细胞侵润为主的IPF样症状，且100%的死亡。体外用M-CSF诱导巨噬细胞分化，发现dKO小鼠BM可以得到更多的巨噬细胞；Western-blot、IP等实验初步提示Cbl-b/C-Cbl可能通过泛素化PU.1影响了MCSFR的转录，并直接泛素化MCSF1R，同时Cbl-b/C-Cbl影响其信号通路中的SHIP1 等分子的稳定性，从多种途径协同作用影响巨噬细胞的分化和成熟。本课题拟在已有预试验基础上，详细研究Cbl-b/C-Cbl对MCSFR本身及其信号通路的影响，阐明Cbl-b/C-Cbl缺失的巨噬细胞诱导IPF的作用机制。

Idiopathic pulmonary fibrosis is a chronic, progressive and interstitial lung disease, Accumulating evidence demonstrated that inflammation caused by macrophages play pivotal role in the development of IPF.However, it is still largely unclear which molecule causes the activation of macrophages. We establish the LysM-Cre+ Cbl-b-/-/C-Cblf/f mouse model with ablation of both Cbl-b/C-Cbl E3 ubiquitin ligase in monocytes / macrophages.The 100% dKO mice were died of IPF like disease in about 35 days. Mature macrophages were infiltrated in lung, the alveolar structure were severely destroyed. dKO mice BM can developed more mature macrophages cultured with M-CSF in vitro, suggests that Cbl-b/C-Cbl may inhibit the MCSF1R pathwy to prevent the differentiation of macrophage. Other preliminary results further suggest that Cbl-b/C-Cbl may ubiquitinate PU.1 which are important transcriptional factor of MCSF1R, and directly ubiquitinated MCSF1R, meanwhile, the Cbl-b/C-Cbl double deficent macrophages have lower expression of SHIP1 which are essential signal molecule in MCSF1R pathway. All together imply that Cbl-b/C-Cbl synergisticly function on the transcription and ubinquitination of MCSF1R,and impair the signal pathway of MCSF1R by down-regulating the SHIP1. In this project, we plan to extensively study the effect of Cbl-b/C-Cbl on MCSF1R and its signal pathway, and clarify the mechanism of Cbl-b/C-Cbl in macrophage-induced IPF.