title: Cross talk of combined gene and cell therapy in ischemic heart disease: role of exosomal microRNA transfer.
abstract: BACKGROUND
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: 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.
authors.forename: Sang-Ging
authors.initials: SG
authors.lastname: Ong
authors.affiliation: 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.
authors.forename: Won Hee
authors.initials: WH
authors.lastname: Lee
authors.affiliation: 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.
authors.forename: Mei
authors.initials: M
authors.lastname: Huang
authors.affiliation: 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.
authors.forename: Devaveena
authors.initials: D
authors.lastname: Dey
authors.affiliation: 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.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kodo
authors.affiliation: 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.
authors.forename: Veronica
authors.initials: V
authors.lastname: Sanchez-Freire
authors.affiliation: 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.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Gold
authors.affiliation: 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. joewu@stanford.edu.
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Wu
mesh_terms: D053687:Adult Stem Cells / Q000637:transplantation*; D000818:Animals; D002450:Cell Communication; D060833:Cellular Microenvironment; D003131:Combined Modality Therapy; D017077:Culture Media, Conditioned; D004270:DNA, Circular; D055354:Exosomes; D005260:Female; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000627:therapeutic use; D006085:Graft Survival; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D008822:Mice, Transgenic; D035683:MicroRNAs / Q000235:genetics / Q000627:therapeutic use*; D039902:Multipotent Stem Cells / Q000637:transplantation*; D009203:Myocardial Infarction / Q000235:genetics / Q000601:surgery / Q000628:therapy*; D017202:Myocardial Ischemia / Q000235:genetics / Q000601:surgery / Q000628:therapy*; D018919:Neovascularization, Physiologic; D010957:Plasmids; D011897:Random Allocation; D014162:Transfection
chemical_list: D017077:Culture Media, Conditioned; D004270:DNA, Circular; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C545201:MIRN126 microRNA, mouse; C549325:MIRN210 microRNA, mouse; D035683:MicroRNAs
keywords: exosomes; genetic therapy; hypoxia-inducible factor-1; microRNAs; stem cells