Ong Sang-Ging, Lee Won Hee, Huang Mei, Dey Devaveena, Kodo Kazuki, Sanchez-Freire Veronica, Gold Joseph D, Wu Joseph C
From the Stanford Cardiovascular Institute (S.-G.O., W.H.L., M.H., D.D., K.K., V.S.-F., J.D.G., J.C.W.); and Division of Cardiology, Department of Medicine (S.-G.O., W.H.L., K.K., V.S.-F., J.C.W.), Department of Radiology (M.H., D.D., J.C.W.), and Department of Cardiothoracic Surgery (J.D.G.), Stanford University School of Medicine, CA.
Circulation. 2014 Sep 9;130(11 Suppl 1):S60-9. doi: 10.1161/CIRCULATIONAHA.113.007917.
Despite the promise shown by stem cells for restoration of cardiac function after myocardial infarction, the poor survival of transplanted cells has been a major issue. Hypoxia-inducible factor-1 (HIF1) is a transcription factor that mediates adaptive responses to ischemia. Here, we hypothesize that codelivery of cardiac progenitor cells (CPCs) with a nonviral minicircle plasmid carrying HIF1 (MC-HIF1) into the ischemic myocardium can improve the survival of transplanted CPCs.
After myocardial infarction, CPCs were codelivered intramyocardially into adult NOD/SCID mice with saline, MC-green fluorescent protein, or MC-HIF1 versus MC-HIF1 alone (n=10 per group). Bioluminescence imaging demonstrated better survival when CPCs were codelivered with MC-HIF1. Importantly, echocardiography showed mice injected with CPCs+MC-HIF1 had the highest ejection fraction 6 weeks after myocardial infarction (57.1±2.6%; P=0.002) followed by MC-HIF1 alone (48.5±2.6%; P=0.04), with no significant protection for CPCs+MC-green fluorescent protein (44.8±3.3%; P=NS) when compared with saline control (38.7±3.2%). In vitro mechanistic studies confirmed that cardiac endothelial cells produced exosomes that were actively internalized by recipient CPCs. Exosomes purified from endothelial cells overexpressing HIF1 had higher contents of miR-126 and miR-210. These microRNAs activated prosurvival kinases and induced a glycolytic switch in recipient CPCs, giving them increased tolerance when subjected to in vitro hypoxic stress. Inhibiting both of these miRs blocked the protective effects of the exosomes.
In summary, HIF1 can be used to modulate the host microenvironment for improving survival of transplanted cells. The exosomal transfer of miRs from host cells to transplanted cells represents a unique mechanism that can be potentially targeted for improving survival of transplanted cells.
尽管干细胞在心肌梗死后恢复心脏功能方面展现出前景，但移植细胞存活率低一直是个主要问题。缺氧诱导因子-1（HIF1）是一种介导对缺血适应性反应的转录因子。在此，我们假设将心脏祖细胞（CPC）与携带HIF1的非病毒微环质粒（MC-HIF1）共同递送进缺血心肌可提高移植CPC的存活率。
心肌梗死后，将CPC与生理盐水、MC-绿色荧光蛋白或MC-HIF1（单独的MC-HIF1作为对照）经心肌内共同递送至成年NOD/SCID小鼠体内（每组n = 10）。生物发光成像显示，当CPC与MC-HIF1共同递送时存活率更高。重要的是，超声心动图显示，心肌梗死后6周，注射CPC + MC-HIF1的小鼠射血分数最高（57.1±2.6%；P = 0.002），其次是单独注射MC-HIF1的小鼠（48.5±2.6%；P = 0.04），与生理盐水对照组（38.7±3.2%）相比，CPC + MC-绿色荧光蛋白组（44.8±3.3%；P值无统计学意义）未显示出显著的保护作用。体外机制研究证实，心脏内皮细胞产生的外泌体被受体CPC主动摄取。从过表达HIF1的内皮细胞中纯化的外泌体含有更高含量的miR-126和miR-210。这些微小RNA激活促存活激酶并诱导受体CPC发生糖酵解转换，使其在体外缺氧应激下具有更高的耐受性。抑制这两种微小RNA可阻断外泌体的保护作用。
总之，HIF1可用于调节宿主微环境以提高移植细胞的存活率。微小RNA从宿主细胞向外泌体的转移代表了一种独特的机制，有望成为提高移植细胞存活率的潜在靶点。
