新型神经营养因子MANF对M2型肿瘤相关巨噬细胞分化和恶性胶质母细胞瘤放疗抗性的影响和机制研究

Radiation induces M2 polarization of tumor-associated macrophages in the tumor microenvironment of Glioblastoma, which results in immunosuppression and radiation resistance. However, how radiation induces M2 polarization is still unknown. MANF has been proved to regulate the polarization of macrophages. We propose that radiation up-regulates HIF-1α of tumor-associated macrophages to increase MANF.expression that promotes M2 polarization of tumor-associated macrophages through MANF autocrine, which leads to immunosuppression and radiation resistance of Glioblastoma. We will construct the mice GL261 glioblastoma radiation model, as well as using the macrophage-specific MANF-/- mice and recombinant human MANF to explore the relevance between radiation-induced MANF autocrine and.tumor-associated macrophage M2 polarization. Also, we will study the transcriptional regulation of HIF-1 on MANF through the direct binding of HIF-1 to MANF promoter. Our research is beneficial for uncovering the mechanism on the radiation-induced tumor-associated macrophage M2 polarization, illuminating the role of MANF in the antitumor immunoregulation and creating new ideas to make a combination of the immunologic intervention and radiotherapy.

辐射诱导恶性胶质母细胞瘤肿瘤微环境中M2型肿瘤相关巨噬细胞分化，从而抑制肿瘤免疫，促进放疗抗性，但辐射诱导M2型分化的关键分子机制仍不清楚。研究发现新型神经营养因子MANF具有调控巨噬细胞分化的作用，故推测：辐射诱导肿瘤相关巨噬细胞HIF-1α上调，促进MANF表达并以自分泌的方式促进肿瘤相关巨噬细胞向M2型分化，抑制肿瘤免疫，导致恶性胶质母细胞瘤放疗抗性。为此，我们构建小鼠GL261脑胶质瘤原位辐照模型，并利用巨噬细胞特异性MANF敲除鼠和表达纯化的重组人MANF蛋白研究辐射诱导的肿瘤相关巨噬细胞MANF自分泌与M2型分化的相关性。同时，我们研究HIF-1通过结合MANF启动子对其转录表达进行直接调节的功能。本研究揭示辐射诱导肿瘤相关巨噬细胞M2型分化的机制，阐明MANF的肿瘤免疫调节功能，为降低恶性胶质母细胞瘤放疗抗性，探索新的免疫干预和放疗相结合的治疗策略提供新的思路。

辐射诱导恶性胶质母细胞瘤肿瘤微环境中M2型肿瘤相关巨噬细胞分化，从而抑制肿瘤免疫，促进放疗抗性，但辐射诱导M2型分化的关键分子机制仍不清楚。研究发现新型神经营养因子MANF具有调控巨噬细胞分化和免疫反应的作用，故推测：辐射诱导肿瘤相关巨噬细胞HIF-1α上调，促进MANF表达并以自分泌的方式促进肿瘤相关巨噬细胞向M2型分化，抑制肿瘤免疫，导致恶性胶质母细胞瘤放疗抗性。我们发现辐射诱导细胞内HIF-1α上调进而结合MANF启动子直接促进MANF的转录表达。此外，通过利用巨噬细胞特异性MANF敲除鼠和重组人MANF（rhMANF）蛋白进行一系列小鼠和细胞实验，我们还发现MANF对急性肾炎损伤、细菌性心肌炎损伤等疾病和巨噬细胞M1/M2型分化的影响，并且我们对MANF调节巨噬细胞功能极化的机制进行了初步研究。本项目研究揭示MANF对于炎症相关疾病的影响以及在巨噬细胞M1/M2型分化过程中扮演的角色，提示rhMANF蛋白在未来可能作为一种有效的抑炎因子被应用于新的免疫干预治疗策略。