EZH2表观调控肾小管上皮细胞和巨噬细胞及其交互作用在肾脏缺血再灌注损伤中的作用与干预策略研究

Renal ischemia-reperfusion injury (IRI) is the leading cause of ischemic acute renal failure and loss of transplant kidney function, and its outcomes are largely dependent on the inflammatory response in the patient's body and the secondary renal tubular epithelial cell apoptosis. Histone methylation / demethylation is an important way to regulate the immune homeostasis and apoptosis homeostasis. We have found that histone methyltransferase EZH2 was overexpressed both in renal tubular epithelial cells and renal macrophages in renal IRI mouse model. Knock down of EZH2 could significantly up-regulate the expression of microRNA let-7c and FOXO3, and promote the polarization of macrophages to M2 type, inhibit the apoptosis of renal tubular epithelial cell. Besides inhibiting EZH2 could decrease the expression of its target molecule H2AK119 and reduce macrophage infiltration, thereby relieving renal IRI. In this study, we will further study the effects of EZH2 on the migration, polarization of macrophages and the induction of mitophagy-mediated apoptosis in renal tubular epithelial cells to promote the process of renal IRI. Our project is expected to reveal the mechanism of EZH2-mediated histone methylation / demethylation balance regulating of renal tubular epithelial cells, macrophages and their interactions. Solid evidences from this project will lay the foundation of establishing novel strategies for renal IRI prevention and treatment.

肾脏缺血再灌注损伤（IRI）是导致缺血性急性肾功能衰竭和移植肾功能丧失的主要原因，其结局多取决于患者机体内炎症免疫反应及其继发的肾小管上皮细胞凋亡。组蛋白甲基化/去甲基化平衡是表观调控机体免疫稳态和凋亡稳态的重要方式。我们预实验发现肾脏IRI小鼠模型肾小管上皮细胞和肾脏巨噬细胞高表达组蛋白甲基转移酶EZH2；干预EZH2可上调EZH2靶分子microRNA let-7c和FOXO3表达，促进巨噬细胞向M2型极化，抑制肾小管上皮细胞凋亡，同时抑制EZH2靶分子H2AK119，减少巨噬细胞浸润，从而缓解肾脏IRI。由此，本项目拟进一步系统研究和明晰EZH2影响巨噬细胞迁移、极化和诱导肾小管上皮细胞线粒体自噬所介导的细胞凋亡促进肾脏IRI的作用；揭示EZH2通过组蛋白甲基化/去甲基化平衡表观调控肾小管上皮细胞和巨噬细胞及其交互作用的机制，为形成以调控EZH2为核心的肾脏IRI防治新策略奠定基础。

肾脏缺血再灌注损伤（IRI）是导致缺血性急性肾功能衰竭和移植肾功能丧失的主要原因，其结局多取决于患者机体内炎症免疫反应及其继发的肾小管上皮细胞凋亡。组蛋白甲基化/去甲基化平衡是表观调控机体免疫稳态和凋亡稳态的重要方式。本项目利用表观调控分子EZH2的抑制剂GSK126干预小鼠的肾脏缺血再灌注模型，小鼠血清中血肌酐水平显著降低，巨噬细胞浸润减少，肾小管上皮细胞凋亡减少，明晰了组蛋白甲基转移酶EZH2促进肾脏IRI的作用，发现新的调控靶点并建立防治新策略。细胞机制分析表明在肾脏缺血再灌注模型中，巨噬细胞和肾小管上皮细胞中EZH2表达上调。抑制EZH2下调M1型巨噬细胞与M2型巨噬细胞的比例，降低小鼠肾小管上皮细胞凋亡水平。进一步的分子机制分析表明巨噬细胞中高表达EZH2，其靶基因microRNA-let-7c表达下调，促进其向M1型炎症性巨噬细胞极化，加剧炎症微环境，另一方面肾小管上皮细胞中EZH2通过组蛋白甲基化抑制FOXO3的表达，进而抑制线粒体自噬破坏其稳态，促进肾小管上皮细胞的凋亡，为形成以调控EZH2为核心的治疗肾脏IRI新策略提供理论基础和实验依据。