MicroRNA-containing extracellular vesicles released from endothelial colony-forming cells modulate angiogenesis during ischaemic retinopathy.

Margaret Dellett,Reinhold J Medina,Jasenka Guduric‐Fuchs,Eoin D Brown,David A Simpson,Alan W Stitt,Anna O'Connor

doi:10.1111/jcmm.13251

Margaret Dellett, Reinhold J Medina + Show 5 more

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https://doi.org/10.1111/jcmm.13251

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Abstract

Endothelial colony‐forming cells (ECFCs) are a defined subtype of endothelial progenitors that modulate vascular repair and promote perfusion in ischaemic tissues. Their paracrine activity on resident vasculature is ill‐defined, but mediated, at least in part, by the transfer of extracellular vesicles (EVs). To evaluate the potential of isolated EVs to provide an alternative to cell‐based therapies, we first performed a physical and molecular characterization of those released by ECFCs. Their effects upon endothelial cells in vitro and angiogenesis in vivo in a model of proliferative retinopathy were assessed. The EVs expressed typical markers CD9 and CD63 and formed a heterogeneous population ranging in size from ~60 to 1500 nm by electron microscopy. ECFC EVs were taken up by endothelial cells and increased cell migration. This was reflected by microarray analyses which showed significant changes in expression of genes associated with angiogenesis. Sequencing of small RNAs in ECFCs and their EVs showed that multiple microRNAs are highly expressed and concentrated in EVs. The functional categories significantly enriched for the predicted target genes of these microRNAs included angiogenesis. Intravitreally delivered ECFC EVs were associated with the vasculature and significantly reduced the avascular area in a mouse oxygen‐induced retinopathy model. Our findings confirm the potential of isolated EVs to influence endothelial cell function and act as a therapy to modulate angiogenesis. The functions associated with the specific microRNAs detected in ECFC EVs support a role for microRNA transfer in mediating the observed effects.

Highlights

With an ageing population and increased prevalence of diabetes and hypertension, ischaemic vascular diseases, such as peripheral artery disease [1], myocardial infarction, and ischaemic retinopathies, are a growing health issue
Isolated endothelial colony-forming cells (ECFCs) tested highly positive for endothelial markers CD-31 and CD-146, whereas it tested negative for haematopoietic markers CD-45 and CD-14 (Fig. S1)
The molecular and functional assays reported in this study confirm the potential of ECFC extracellular vesicles (EVs) to modulate endothelial cell behaviour and influence angiogenesis in vivo, supporting previous reports that exosomes from ECFCs can block human umbilical vein endothelial cell apoptosis and protect against acute kidney injury [3]

Summary

Introduction

With an ageing population and increased prevalence of diabetes and hypertension, ischaemic vascular diseases, such as peripheral artery disease [1], myocardial infarction, and ischaemic retinopathies, are a growing health issue. Recognition of the therapeutic potential of EVs from mesenchymal and neural stem cells and cardiac and endothelial progenitor cells [7, 8] has made them the focus of intense study. They have been demonstrated to transfer proteins, mRNAs, and microRNAs to recipient cells [9,10,11,12,13,14,15] and have the ability to modulate endothelial cell behaviour in vitro [16,17,18,19] and angiogenesis in vivo [18, 20]. Intercellular transfer of these microRNAs via EVs can a 2017 The Authors

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