Department of Emergency Medicine and Medicine, Thomas Jefferson University, Philadelphia, PA (L.G., D.X., J.L, W.B.L., T.A.C., B.L., L.Z., X.-L.M., Y.W.).
Laboratory of Anesthesia and Critical Care Medicine, Department of Anesthesiology, Translational Neuroscience Center, West China Hospital, Sichuan University, Chengdu, China (L.G.).
Circulation. 2020 Mar 24;141(12):968-983. doi: 10.1161/CIRCULATIONAHA.119.042640. Epub 2020 Jan 10.
Diabetes mellitus exacerbates myocardial ischemia/reperfusion (MI/R) injury by incompletely understood mechanisms. Adipocyte dysfunction contributes to remote organ injury. However, the molecular mechanisms linking dysfunctional adipocytes to increased MI/R injury remain unidentified. The current study attempted to clarify whether and how small extracellular vesicles (sEV) may mediate pathological communication between diabetic adipocytes and cardiomyocytes, exacerbating MI/R injury.
Adult male mice were fed a normal or a high-fat diet for 12 weeks. sEV (from diabetic serum, diabetic adipocytes, or high glucose/high lipid-challenged nondiabetic adipocytes) were injected intramyocardially distal of coronary ligation. Animals were subjected to MI/R 48 hours after injection.
Intramyocardial injection of diabetic serum sEV in the nondiabetic heart significantly exacerbated MI/R injury, as evidenced by poorer cardiac function recovery, larger infarct size, and greater cardiomyocyte apoptosis. Similarly, intramyocardial or systemic administration of diabetic adipocyte sEV or high glucose/high lipid-challenged nondiabetic adipocyte sEV significantly exacerbated MI/R injury. Diabetic epididymal fat transplantation significantly increased MI/R injury in nondiabetic mice, whereas administration of a sEV biogenesis inhibitor significantly mitigated MI/R injury in diabetic mice. A mechanistic investigation identified that miR-130b-3p is a common molecule significantly increased in diabetic serum sEV, diabetic adipocyte sEV, and high glucose/high lipid-challenged nondiabetic adipocyte sEV. Mature (but not primary) miR-130b-3p was significantly increased in the diabetic and nondiabetic heart subjected to diabetic sEV injection. Whereas intramyocardial injection of a miR-130b-3p mimic significantly exacerbated MI/R injury in nondiabetic mice, miR-130b-3p inhibitors significantly attenuated MI/R injury in diabetic mice. Molecular studies identified AMPKα1/α2, Birc6, and Ucp3 as direct downstream targets of miR-130b-3p. Overexpression of these molecules (particularly AMPKα2) reversed miR-130b-3p induced proapoptotic/cardiac harmful effect. Finally, miR-130b-3p levels were significantly increased in plasma sEV from patients with type 2 diabetes mellitus. Incubation of cardiomyocytes with diabetic patient sEV significantly exacerbated ischemic injury, an effect blocked by miR-130b-3p inhibitor.
We demonstrate for the first time that miR-130b-3p enrichment in dysfunctional adipocyte-derived sEV, and its suppression of multiple antiapoptotic/cardioprotective molecules in cardiomyocytes, is a novel mechanism exacerbating MI/R injury in the diabetic heart. Targeting miR-130b-3p mediated pathological communication between dysfunctional adipocytes and cardiomyocytes may be a novel strategy attenuating diabetic exacerbation of MI/R injury.
糖尿病通过尚未完全阐明的机制加重心肌缺血/再灌注（MI/R）损伤。脂肪细胞功能障碍导致远处器官损伤。然而，将功能失调的脂肪细胞与增加的 MI/R 损伤联系起来的分子机制仍不清楚。本研究试图阐明小细胞外囊泡（sEV）是否以及如何介导糖尿病脂肪细胞与心肌细胞之间的病理通讯，从而加重 MI/R 损伤。
成年雄性小鼠接受正常或高脂肪饮食 12 周。sEV（来自糖尿病血清、糖尿病脂肪细胞或高葡萄糖/高脂质挑战的非糖尿病脂肪细胞）被注射到冠状动脉结扎远端的心肌内。注射后 48 小时，动物进行 MI/R。
向非糖尿病心脏内注射糖尿病血清 sEV 可显著加重 MI/R 损伤，表现为心脏功能恢复较差、梗死面积较大和心肌细胞凋亡增加。同样，向非糖尿病心肌内或全身给予糖尿病脂肪细胞 sEV 或高葡萄糖/高脂质挑战的非糖尿病脂肪细胞 sEV 可显著加重 MI/R 损伤。糖尿病附睾脂肪移植可显著增加非糖尿病小鼠的 MI/R 损伤，而给予 sEV 生物发生抑制剂可显著减轻糖尿病小鼠的 MI/R 损伤。一项机制研究发现，miR-130b-3p 是一种在糖尿病血清 sEV、糖尿病脂肪细胞 sEV 和高葡萄糖/高脂质挑战的非糖尿病脂肪细胞 sEV 中明显增加的共同分子。在接受糖尿病 sEV 注射的糖尿病和非糖尿病心脏中，成熟（而非原始）miR-130b-3p 明显增加。向非糖尿病小鼠心肌内注射 miR-130b-3p 模拟物可显著加重 MI/R 损伤，而 miR-130b-3p 抑制剂可显著减轻糖尿病小鼠的 MI/R 损伤。分子研究确定 AMPKα1/α2、Birc6 和 Ucp3 为 miR-130b-3p 的直接下游靶标。这些分子（特别是 AMPKα2）的过表达可逆转 miR-130b-3p 诱导的促凋亡/心脏有害作用。最后，在 2 型糖尿病患者的血浆 sEV 中，miR-130b-3p 水平明显升高。用糖尿病患者 sEV 孵育心肌细胞可显著加重缺血损伤，而 miR-130b-3p 抑制剂可阻断该损伤。
我们首次证明，功能失调的脂肪细胞衍生的 sEV 中 miR-130b-3p 的富集及其在心肌细胞中对多种抗凋亡/心脏保护分子的抑制作用，是加重糖尿病心脏中 MI/R 损伤的新机制。靶向 miR-130b-3p 介导的功能失调脂肪细胞与心肌细胞之间的病理通讯，可能是减轻糖尿病加重 MI/R 损伤的新策略。
