Diabetic nephropathy (DN) is the primary reason of chronic kidney disease. The aim of our study is to explore the role and action mechanism of M2 macrophage‐derived exosomes in high glucose (HG)‐induced podocytes injury. Here, 30 mmol/L of HG was used to induce podocytes injury. Annexin V‐FITC/PI double staining was performed to measure podocytes apoptosis, and western blot was carried out to ensure proteins expression. The shape of exosomes was identified using TEM. Besides, the expression of miR‐25‐3p was determined by qRT‐PCR, FAM‐labeled miR‐25‐5p combined with DiI‐labeled exosomes were utilized to explore the uptake of podocytes to exosomes. Relationship between miR‐25‐3p and DUSP family members was ensued by luciferase activity assay. In the beginning, we found that M2 macrophage ameliorated HG‐induced podocytes apoptosis and epithelial‐mesenchymal transition through secreting exosomes. Subsequently, highly expressed miR‐25‐3p was found in M2 macrophage‐derived exosomes that effectively improved HG‐induced podocytes injury. Furthermore, inhibition of miR‐25‐3p in M2 macrophage inefficiently repressed HG‐induced podocytes injury, thus we proposed that M2 macrophage attenuated podocytes injury through secreting exosomal miR‐25‐3p. Then, we used an autophagy inhibitor to stimulate podocytes, and demonstrated that M2 macrophage‐derived exosomal miR‐25‐3p improved HG‐induced podocytes injury through activating autophagy. Finally, DUSP1 was proved to be a downstream target and mediated the inhibition of exosomal miR‐25‐3p to HG‐induced podocytes injury. Our results indicated that M2 macrophage could improve HG‐induced podocytes injury via secreting exosomal miR‐25‐3p to activate autophagy of the cells through suppressing DUSP1 expression. We proved a newly potential therapy strategy for DN treatment.

中文翻译：

---

M2巨噬细胞衍生的外泌体miR-25-3p通过抑制DUSP1表达激活自噬改善高糖诱导的足细胞损伤

糖尿病肾病（DN）是慢性肾脏病的主要原因。我们研究的目的是探讨 M2 巨噬细胞衍生的外泌体在高糖 (HG) 诱导的足细胞损伤中的作用和作用机制。在这里，30 mmol/L 的 HG 用于诱导足细胞损伤。Annexin V-FITC/PI双染色检测足细胞凋亡，Western Blot检测蛋白表达。使用 TEM 鉴定外泌体的形状。此外，通过qRT-PCR测定miR-25-3p的表达，利用FAM标记的miR-25-5p结合DiI标记的外泌体来探索足细胞对外泌体的摄取。miR-25-3p 和 DUSP 家族成员之间的关系由荧光素酶活性测定确定。在一开始的时候，我们发现 M2 巨噬细胞通过分泌外泌体改善了 HG 诱导的足细胞凋亡和上皮间质转化。随后，在 M2 巨噬细胞衍生的外泌体中发现了高表达的 miR-25-3p，可有效改善 HG 诱导的足细胞损伤。此外，在 M2 巨噬细胞中抑制 miR-25-3p 不能有效地抑制 HG 诱导的足细胞损伤，因此我们提出 M2 巨噬细胞通过分泌外泌体 miR-25-3p 减轻足细胞损伤。然后，我们使用自噬抑制剂刺激足细胞，并证明 M2 巨噬细胞衍生的外泌体 miR-25-3p 通过激活自噬改善了 HG 诱导的足细胞损伤。最后，DUSP1 被证明是一个下游靶点，并介导了外泌体 miR-25-3p 对 HG 诱导的足细胞损伤的抑制。我们的结果表明，M2巨噬细胞可以通过分泌外泌体miR-25-3p通过抑制DUSP1表达激活细胞自噬来改善HG诱导的足细胞损伤。我们证明了 DN 治疗的一种新的潜在治疗策略。