透明质酸通过p38/Blimp1通路调控肝内常驻CD103+CD8+T细胞分化参与肝癌免疫治疗抵抗的分子机制研究

三级淋巴滤泡结构（TLS）形成是预测肿瘤免疫治疗疗效的重要标志，然而TLS在肝癌中的调控机制尚未阐明。我们前期研究发现CXCL13促进免疫细胞在肝内聚集，而肝癌中CXCL13可能由CD8A和CD103阳性的细胞分泌。体外实验发现肝癌细胞分泌的透明质酸（HA）促进肝内常驻CD103+CD8+T细胞（TRM）p38磷酸化，抑制Blimp1和CXCL13表达。小鼠肝癌实验发现透明质酸酶增强PD-1抗体对肝癌的抑制。为此，我们推测肝癌微环境中HA通过p38/Blimp1信号通路抑制TRM分化和CXCL13表达，阻碍TLS形成，促进肿瘤免疫逃逸和免疫治疗抵抗。本项目拟在前期研究基础上，探索透明质酸结合TRM的受体，以及通过染色质免疫共沉淀实验探索Blimp1对TRM细胞基因表达的调控机制。本研究首次从肝癌微环境中HA与TRM细胞相互作用的角度探索肝癌免疫治疗抵抗的机制，为肝癌综合治疗提供全新的思路。

The formation of tertiary lymphoid structures (TLS) is an important biomarker in predicting the efficacy of immunotherapy in tumor patients. However, the regulatory mechanism of TLS in liver cancer has not been elucidated. In our previous study, we have found that high levels of CXCL13 promoted the recruitment of immune cells in the liver. And the source of CXCL13 was mainly secreted by CD8A and CD103 positive immune cells. In vitro studies showed that hyaluronic acid (HA) secreted by cancer cells promoted the phosphorylation of p38 and inhibited the expression of Blimp1 and CXCL13 in CD103+CD8+T cells (Trm). Hyaluronidase could enhance the anti-tumor efficacy of PD-1 antibody in the mouse hepatoma model. Therefore, we speculated that HA in tumor microenvironment could inhibit Trm cell differentiation and CXCL13 expression through p38/Blimp1 signaling pathway, which impeded the formation of TLS and promoted tumor immune escape and immunotherapy resistance. Based on previous experimental results, we intended to further verify which receptor on Trm cells did HA bind to. Then chromatin-immunoprecipitation experiment was used to explore the regulatory mechanism of Blimp1 on Trm cells. This is the first study to explore the mechanism of immunotherapy resistance from the perspective of the interaction between HA and Trm cells in the tumor microenvironment, which help to provide a new idea for the comprehensive treatment of liver cancer.