CARD9调控DCs糖代谢重塑其功能介导胰腺癌发生发展的作用机制研究

The phenotype and function of dendritic cells (DCs) are closely related to glucose metabolism. The tumor tissues infiltrated DCs of pancreatic cancer exhibit immunotolerant properties, which are regulated by intracellular inflammation pathway and glucose metabolism pathway. CARD9 (caspase-associated recruitment domain 9) is an important adapter protein that regulates multiple signaling pathways in DCs and macrophages, and plays an important role in inflammatory signal transduction. Our previous studies found that the immunogenicity of bone marrow-derived DCs decreased in the progression of pancreatic cancer, which was accompanied with downregulated CARD9 expression. CARD9 altered glucose uptake, expression of glycolysis-related genes and proteins, acidic metabolites of DCs. Whether CARD9 modulates the glucose metabolism and function remodeling of DCs has not been reported. We intend to investigate how CARD9 regulates the glycolysis, oxidative phospholation and function remodeling of DCs in the transgenic animal models and tumor microenvironment of pancreatic cancer, by modulating the inflammation-related NF-κB pathway and metabolism-related MAPK/P38, PI3K/Akt/FoxO1 pathways in DCs. Our study will elucidate the new molecular mechanism underlying glucose metabolism and function remodeling of DCs in pancreatic cancer, and new approach for immunotherapy based on DCs.

树突状细胞DCs的表型和功能与糖代谢密切相关。胰腺癌组织浸润DCs呈现免疫耐受性，其功能重塑受细胞内炎性通路和糖代谢通路等调控。胱天蛋白酶募集域蛋白CARD9为主要表达于DCs和巨噬细胞中的调控多条信号通路传导的衔接蛋白，在炎症信号转导过程中发挥重要作用。前期研究发现伴随胰腺癌发生发展DCs免疫原性降低，胞内CARD9表达下调；此外，CARD9的表达影响了糖吸收、糖酵解相关基因和蛋白表达及糖代谢产物产生。CARD9是否介导DCs糖代谢和功能重塑未见报道。我们拟用胰腺癌转基因动物模型和肿瘤微环境模型，以CARD9关联的炎性通路NF-κB和糖代谢通路MAPK/P38、PI3K/Akt/FoxO1为切入点，研究CARD9调控DCs糖酵解和氧化磷酸化等糖代谢，改变DCs免疫功能，介导胰腺癌发生发展的作用及机制，以揭示胰腺癌DCs糖代谢和功能重塑的新机制和基于DCs的胰腺癌肿瘤免疫治疗新方法。

胰腺癌是一种预后差、死亡率高的肿瘤。近年来CARD9被报道与多种肿瘤发展密切相关。本研究旨在阐明CARD9介导DC成熟进而调控胰腺癌进展的分子机制。我们发现CARD9表达水平与胰腺癌患者生存期呈正相关，表明CARD9可能参与胰腺癌进展。利用CRISPR-Cas9技术构建CARD9敲除鼠，CARD9敲除后肿瘤生长更快、生存期更短，肿瘤部位DC显著减少。体外实验表明CARD9敲除抑制DC成熟和功能。构建CD11c-DTR小鼠以获得DC清除小鼠，DC过继转移实验结果显示与野生型DC相比，CARD9缺陷DC显著加重CD11c-DTR小鼠的胰腺癌症状，证实CARD9缺陷通过抑制DC成熟促进胰腺癌发生。随后，我们发现人参皂苷Rh2激活CARD9-BCL10-MALT1/p65通路，诱导DC成熟和CD8+T细胞激活，加强抗肿瘤免疫应答。Rh2与吉西他滨联合用药显著改善后者抗胰腺癌疗效，降低骨髓抑制副作用。表明CARD9可作为胰腺癌的治疗靶点。代谢组学分析发现CARD9敲除显著影响DC的氨基酸代谢，尤其是精氨酸和脯氨酸通路中的肌酸，且强于糖脂代谢的影响。本项目揭示CARD9激活促进DC成熟进而诱导抗肿瘤免疫的机制，发现潜在的治疗新靶点，为胰腺癌治疗方案提供新思路。