间充质干细胞靶向ATM/BID/NOD1/2通路对肠炎及其恶化的调控机制

Mesenchymal stem cells (MSCs) have the ability to home to sites of inflammation and cancer, and BID-mediated DNA damage response and innate immune signaling pathways are the important molecular mechanisms in the progression of malignant transformation of the epithelial cells. However, the malignant transformation mechanisms of colitis and the function roles of MSCs in the colitis-associated cancer are not clear. So this proposal is focused on studying the colitis and colitis-associated cancer models that induced by DSS, AOM/DSS, colon epithelium cells and colon cancer cell lines. In vitro, we use tail vein injection and cell co-cultured, after interference the DNA damage signal moleculars ATM, BID and immune moleculars NOD1, NOD2, confirmed that the biology function of MSCs mediated on chronic enteritis translate to colon cancer. Focus on tumor-homing of MSCs and its effects on the releasing of ROS, RNS during inflammation progression which can cause DNA damage. On the mechanisms, we will clarify that the ATM/BID/NOD1/2 signaling pathways are the major molecular mechanisms to regulate the malignant transformation of colitis by activating DNA damage check-points and natural immune response, furthermore,the function of MSCs in these pathways will be summarized. Simultaneously, we will further analysis some clinical samples of inflammatory bowel disease and colon cancer in order to look for some potential check-point proteins or immune moleculars as a marker of colitis-associated cancer, in order to lay a foundation for the application of clinical medicine.

BID介导的DNA损伤和天然免疫信号通路是调控上皮细胞恶性转变的重要分子机制，然而肠炎恶变的分子机制和向炎症组织归巢的间充质干细胞(MSCs)在其中的调控作用尚不明确。利用DSS、AOM/DSS诱导肠炎及其相关性肠癌模型和肠上皮、肠癌细胞株为研究对象，采取MSCs尾静脉注射和体外细胞共培养等手段，在干预DNA损伤信号分子ATM、BID和免疫相关分子NOD1/2后，1）分析MSCs在从肠炎到肠癌恶变中所介导的生物学功能，重点研究MSCs的归巢对炎症恶变过程中释放的ROS、RNS致DNA损伤的影响；2）从激活DNA损伤检控点和天然免疫应答的角度，阐明ATM/BID/NOD1/2信号通路是调控肠炎恶性转化的重要分子机制，并进一步明确MSCs对该通路的调节；3）结合正常和炎症性肠病及肠癌病患的临床标本分析，寻找可能的检控蛋白或免疫相关分子作为肠炎恶变的标志分子，为其在临床医学上的应用奠定理论基础。

紧紧围绕着项目年度研究计划，首先，完成了MSCs 在DSS诱导的肠炎小鼠体内的分布（归巢）及其利用TNF-α和IFN-γ激活MSCs NF-кB通路后对肠炎发展的影响。进一步证明了MSCs本身对结肠炎相关性肠癌修复作用明显，而经TNF-α和IFN-γ共同预处理后这种修复作用被反转甚至更加加重肿瘤的发展，具体机制为TNF-α、IFN-γ激活MSCs自身和小鼠体内的Wnt/β-catenin通路，对MSCs产生一定损伤，削弱其对结肠炎相关性肠癌小鼠的修复能力进而促进肠道肿瘤的进展。从激活DNA 损伤检控点和天然免疫应答的角度，特别是从ATM/BID/NOD1/2 信号通路的角度探究MSCs 对肠炎（癌）的调控也取得了一些有意义的结果。. 其次，建立APCmin小鼠的炎癌模型，发现Berberine通过抑制Wnt/β-catenin信号通路可以降低炎症和息肉的形成。进一步在家族性结肠息肉病人的临床治疗中发现Berberine可明显抑制息肉的形成。同时以上述建立模型，进行了包括人参皂甙次级代谢产物CK等单体化合物的抗炎的功能机制研究。. 再者，在执行本项目过程中，我们发现USP39一个全新的分子可能在调控包括炎症性肠癌在内的恶性肿瘤发生发展过程起更为重要的作用，其机制可能与调控periostin的RNA剪切或者蛋白表达紧密相关，这一发现为我们下一步深入开展本课题打下了基础。