Abstract：
BACKGROUND: Ischemia-reperfusion injury (IRI) is an inevitable process in renal transplantation that significantly increases the risk of delayed graft function, acute rejection, and even graft loss. Formyl peptide receptor 2 (FPR2) is an important receptor in multiple septic and aseptic injuries, but its functions in kidney IRI are still unclear. This study was designed to reveal the pathological role of FPR2 in kidney IRI and its functional mechanisms.
METHODS: To explore the mechanism of FPR2 in kidney IRI, the model rats were sacrificed after IRI surgery. Immunofluorescence, enzyme-linked immunosorbent assays, and western blotting were used to detect differences in the expression of FPR2 and its ligands between the IRI and control groups. WRW4 (WRWWWW-NH2), a specific antagonist of FPR2, was administered to kidney IRI rats. Kidney function and pathological damage were detected to assess kidney injury and recovery. Flow cytometry was used to quantitatively compare neutrophil infiltration among the experimental groups. Mitochondrial formyl peptides (mtFPs) were synthesized and administered to primary rat neutrophils together with the specific FPR family antagonist WRW4 to verify our hypothesis in vitro. Western blotting and cell function assays were used to examine the functions and signaling pathways that FPR2 mediates in neutrophils.
RESULTS: FPR2 was activated mainly by mtFPs during the acute phase of IRI, mediating neutrophil migration and reactive oxygen species production in the rat kidney through the ERK1/2 pathway. FPR2 blockade in the early phase protected rat kidneys from IRI.
CONCLUSIONS: mtFPs activated FPR2 during the acute phase of IRI and mediated rat kidney injury by activating the migration and reactive oxygen species generation of neutrophils through the ERK1/2 pathway.
METHODS: To explore the mechanism of FPR2 in kidney IRI, the model rats were sacrificed after IRI surgery. Immunofluorescence, enzyme-linked immunosorbent assays, and western blotting were used to detect differences in the expression of FPR2 and its ligands between the IRI and control groups. WRW4 (WRWWWW-NH2), a specific antagonist of FPR2, was administered to kidney IRI rats. Kidney function and pathological damage were detected to assess kidney injury and recovery. Flow cytometry was used to quantitatively compare neutrophil infiltration among the experimental groups. Mitochondrial formyl peptides (mtFPs) were synthesized and administered to primary rat neutrophils together with the specific FPR family antagonist WRW4 to verify our hypothesis in vitro. Western blotting and cell function assays were used to examine the functions and signaling pathways that FPR2 mediates in neutrophils.
RESULTS: FPR2 was activated mainly by mtFPs during the acute phase of IRI, mediating neutrophil migration and reactive oxygen species production in the rat kidney through the ERK1/2 pathway. FPR2 blockade in the early phase protected rat kidneys from IRI.
CONCLUSIONS: mtFPs activated FPR2 during the acute phase of IRI and mediated rat kidney injury by activating the migration and reactive oxygen species generation of neutrophils through the ERK1/2 pathway.
摘要：
背景：缺血再灌注损伤（IRI）是肾移植中不可避免的过程，显着增加移植功能延迟的风险，急性排斥反应,甚至是嫁接损失。甲酰基肽受体2(FPR2)是多种败血症和无菌损伤的重要受体,但其在肾脏IRI中的功能仍不清楚。本研究旨在揭示FPR2在肾脏IRI中的病理作用及其作用机制。
方法：探讨FPR2在肾脏IRI中的作用机制,IRI手术后处死模型大鼠。免疫荧光,酶联免疫吸附测定，和蛋白质印迹用于检测IRI组和对照组之间FPR2及其配体表达的差异。WRW4(WRWWWW-NH2),对肾脏IRI大鼠施用FPR2的特异性拮抗剂。检测肾功能和病理损害以评估肾损伤和恢复。流式细胞术用于定量比较实验组之间的中性粒细胞浸润。合成了线粒体甲酰肽（mtFP），并将其与特定的FPR家族拮抗剂WRW4一起施用于原代大鼠中性粒细胞，以在体外验证我们的假设。使用蛋白质印迹和细胞功能测定来检查FPR2在嗜中性粒细胞中介导的功能和信号传导途径。
结果：FPR2在IRI急性期主要被mtFP激活，通过ERK1/2途径介导大鼠肾脏中的中性粒细胞迁移和活性氧的产生。早期阶段的FPR2阻断保护大鼠肾脏免受IRI。
结论：mtFP在IRI急性期激活FPR2，并通过ERK1/2途径激活中性粒细胞的迁移和活性氧的生成，从而介导大鼠肾损伤。
方法：探讨FPR2在肾脏IRI中的作用机制,IRI手术后处死模型大鼠。免疫荧光,酶联免疫吸附测定，和蛋白质印迹用于检测IRI组和对照组之间FPR2及其配体表达的差异。WRW4(WRWWWW-NH2),对肾脏IRI大鼠施用FPR2的特异性拮抗剂。检测肾功能和病理损害以评估肾损伤和恢复。流式细胞术用于定量比较实验组之间的中性粒细胞浸润。合成了线粒体甲酰肽（mtFP），并将其与特定的FPR家族拮抗剂WRW4一起施用于原代大鼠中性粒细胞，以在体外验证我们的假设。使用蛋白质印迹和细胞功能测定来检查FPR2在嗜中性粒细胞中介导的功能和信号传导途径。
结果：FPR2在IRI急性期主要被mtFP激活，通过ERK1/2途径介导大鼠肾脏中的中性粒细胞迁移和活性氧的产生。早期阶段的FPR2阻断保护大鼠肾脏免受IRI。
结论：mtFP在IRI急性期激活FPR2，并通过ERK1/2途径激活中性粒细胞的迁移和活性氧的生成，从而介导大鼠肾损伤。
