de Couto Geoffrey, Gallet Romain, Cambier Linda, Jaghatspanyan Ervin, Makkar Nupur, Dawkins James Frederick, Berman Benjamin P, Marbán Eduardo
From Cedars-Sinai Heart Institute, Los Angeles, CA (G.d.C., R.G., L.C., E.J., N.M., J.F.D., B.P.B., E.M.); and Cedars-Sinai Center for Bioinformatics and Functional Genomics, Los Angeles, CA (B.P.B.).
Circulation. 2017 Jul 11;136(2):200-214. doi: 10.1161/CIRCULATIONAHA.116.024590. Epub 2017 Apr 14.
Cardiosphere-derived cells (CDCs) confer cardioprotection in acute myocardial infarction by distinctive macrophage (Mϕ) polarization. Here we demonstrate that CDC-secreted exosomes (CDC) recapitulate the cardioprotective effects of CDC therapy known as cellular postconditioning.
Rats and pigs underwent myocardial infarction induced by ischemia/reperfusion before intracoronary infusion of CDC, inert fibroblast exosomes (Fb; control), or vehicle. Two days later, infarct size was quantified. Macrophages were isolated from cardiac tissue or bone marrow for downstream analyses. RNA sequencing was used to determine exosome content and alterations in gene expression profiles in Mϕ.
Administration of CDC but not Fb after reperfusion reduces infarct size in rat and pig models of myocardial infarction. Furthermore, CDC reduce the number of CD68+ Mϕ within infarcted tissue and modify the polarization state of Mϕ so as to mimic that induced by CDCs. CDC are enriched in several miRNAs (including miR-146a, miR-181b, and miR-126) relative to Fb. Reverse pathway analysis of whole-transcriptome data from CDC-primed Mϕ implicated miR-181b as a significant (=1.3x10) candidate mediator of CDC-induced Mϕ polarization, and PKCδ (protein kinase C δ) as a downstream target. Otherwise inert Fb loaded selectively with miR-181b alter Mϕ phenotype and confer cardioprotective efficacy in a rat model of myocardial infarction. Adoptive transfer of PKCδ-suppressed Mϕ recapitulates cardioprotection.
Our data support the hypothesis that exosomal transfer of miR-181b from CDCs into Mϕ reduces PKCδ transcript levels and underlies the cardioprotective effects of CDCs administered after reperfusion.
心肌球衍生细胞（CDCs）通过独特的巨噬细胞（Mϕ）极化在急性心肌梗死中发挥心脏保护作用。在此我们证明，CDC分泌的外泌体（CDC）概括了被称为细胞后适应的CDC疗法的心脏保护作用。
大鼠和猪在冠状动脉内输注CDC、惰性成纤维细胞外泌体（Fb；对照）或赋形剂之前，先经历缺血/再灌注诱导的心肌梗死。两天后，对梗死面积进行定量。从心脏组织或骨髓中分离巨噬细胞用于下游分析。RNA测序用于确定外泌体内容物以及Mϕ中基因表达谱的变化。
再灌注后给予CDC而非Fb可减小大鼠和猪心肌梗死模型中的梗死面积。此外，CDC减少梗死组织内CD68+ Mϕ的数量，并改变Mϕ的极化状态，从而模拟由CDCs诱导的极化状态。相对于Fb，CDC富含几种miRNA（包括miR-146a、miR-181b和miR-126）。对来自CDC预处理的Mϕ的全转录组数据进行反向通路分析表明，miR-181b是CDC诱导的Mϕ极化的重要（=1.3x10）候选介质，而蛋白激酶Cδ（PKCδ）是下游靶点。否则，选择性装载miR-181b的惰性Fb会改变Mϕ表型，并在大鼠心肌梗死模型中赋予心脏保护功效。PKCδ抑制的Mϕ的过继转移概括了心脏保护作用。
我们的数据支持以下假设，即miR-181b从CDCs向外泌体转移至Mϕ可降低PKCδ转录水平，并构成再灌注后给予CDCs的心脏保护作用的基础。
