Table_1_Receptor Tyrosine Kinase Inhibitor Sunitinib as Novel Immunotherapy to Inhibit Myeloid-Derived Suppressor Cells for Treatment of Endometriosis.xlsx

Endometriosis is a common, benign, and hormone-dependent gynaecological disorder that displays altered immunoinflammatory profiles. Myeloid-derived suppressor cells (MDSCs) suppressed immunosurveillance in endometriosis in human and mouse model. Receptor tyrosine kinase inhibitor Sunitinib can induce MDSC apoptosis and suppress the progression of cancer. However, the effects of Sunitinib on MDSCs in endometriosis and the underlying mechanism are not clear. In this study, we employed an animal study of the endometriosis model in mice for treatment of Sunitinib. After syngeneic endometrium transplantation and treatment, endometriotic lesion volume, weight, and histology were compared. Peritoneal fluid, peripheral blood, and bone marrow MDSC subsets and their molecular signaling were monitored by flow cytometry. Peritoneal cytokines were assayed by ELISA. The gene expression profiles of isolated CD11b+Ly6G+Ly6Clo cells were studied by RNA sequencing. We found that Sunitinib significantly decreased the endometriotic lesion size and weight after 1 and 3 weeks, and decreased p-STAT3 activation in MDSCs after 1 week of treatment. In the first week, Sunitinib specifically increased the G-MDSC population in peritoneal fluid but the isolated CD11b+Ly6G+Ly6Clo MDSCs after Sunitinib treatment were presented as mature polynuclear MDSCs, while the control group had immature mononuclear MDSCs. Importantly, we found Sunitinib differentially suppressed gene expressions of immunosuppressive function and differentiation in peritoneal G-MDSCs. Apelin signaling pathway associated genes and inflammation related genes were upregulated, and amino acid metabolism regulator genes were downregulated in bone marrow G-MDSCs. For endometriotic lesions, the PPARG gene governing glucose metabolism and fatty acid storage, which is important for the development of endometriosis was upregulated. In conclusion, Sunitinib inhibited endometriotic lesions, by promoting peritoneal fluid MDSCs maturation and inhibiting the immunosuppressive function. These findings suggest that Sunitinib changed the immune microenvironment and inhibited the development of endometriosis, which has potential therapeutic effects as novel immunotherapy to promote MDSCs maturation, differentiation, and metabolism for the treatment of endometriosis.

子宫内膜异位症（Endometriosis）是一种常见的良性激素依赖性妇科疾病，其免疫炎症谱存在异常改变。髓系来源抑制细胞（Myeloid-derived suppressor cells, MDSCs）在人类及小鼠子宫内膜异位症模型中可抑制免疫监视功能。受体酪氨酸激酶抑制剂舒尼替尼（Sunitinib）可诱导MDSCs凋亡并抑制癌症进展，然而其对子宫内膜异位症中MDSCs的作用及潜在分子机制尚不明确。本研究采用小鼠子宫内膜异位症模型开展舒尼替尼干预实验：在完成同基因子宫内膜移植并给药后，比较各组异位病灶的体积、重量及组织学特征；通过流式细胞术（flow cytometry）检测腹腔积液、外周血及骨髓中的MDSC亚群及其分子信号通路；采用酶联免疫吸附试验（ELISA）检测腹腔细胞因子水平；通过RNA测序（RNA sequencing）分析分离得到的CD11b+Ly6G+Ly6Clo细胞的基因表达谱。研究结果显示，给药1周及3周后，舒尼替尼可显著降低异位病灶的体积与重量，并在给药1周后降低MDSCs中p-STAT3的激活水平。给药第一周时，舒尼替尼可特异性增加腹腔积液中的粒细胞样髓系来源抑制细胞（G-MDSCs）群体；经舒尼替尼处理后分离得到的CD11b+Ly6G+Ly6Clo MDSCs呈现为成熟的多核MDSCs，而对照组则为未成熟的单核MDSCs。值得注意的是，舒尼替尼可差异化抑制腹腔G-MDSCs中免疫抑制功能及分化相关基因的表达；在骨髓G-MDSCs中，Apelin信号通路（Apelin signaling pathway）相关基因及炎症相关基因表达上调，而氨基酸代谢调控基因表达下调。对于异位病灶而言，调控葡萄糖代谢与脂肪酸储存的过氧化物酶体增殖物激活受体γ（PPARG）——该基因对子宫内膜异位症的发生发展具有重要作用——表达显著上调。综上，舒尼替尼通过促进腹腔积液中MDSCs的成熟并抑制其免疫抑制功能，从而抑制异位病灶的进展。上述研究结果表明，舒尼替尼可重塑免疫微环境并抑制子宫内膜异位症的发展，其作为新型免疫治疗手段，通过促进MDSCs的成熟、分化及代谢调控治疗子宫内膜异位症，具备潜在的临床应用价值。