C166 Exosomes are a Novel Fibroblast Selective Delivery System Which Potentiates miR Cardiac Reprogramming

Abstract

Background: We have demonstrated that directly reprogramming fibroblasts into new cardiomyocytes via miR combo improves cardiac function in the infarcted heart. A major challenge is delivery as viral approaches lack cell-specificity.

Objectives: As an alternative to the standard viral approaches, we evaluated exosomes.

Methods: Exosome screening, knockdown, myocardial infarction, fibroblast lineage tracing.

Results: Through a screening based approach, we discovered that C166-derived exosomes preferentially targeted fibroblasts in vitro and in vivo. C166-derived exosomes proved to be effective delivery agents. MiR combo delivery via C166-derived exosomes induced significant conversion of fibroblasts into cardiomyocytes. In addition, there was a significant improvement in cardiac function in a myocardial infarction injury model. When compared to lipid-based transfection, C166-derived exosome delivery of miR combo enhanced reprogramming efficacy. Improved reprogramming efficacy was found to result from a miRNA within the exosome: miR-148a-3p. The target of miR-148a-3p was identified as Mdfic. Over-expression and targeted knockdown studies demonstrated that Mdfic was a cardiomyocyte gene repressor.

Conclusions: We have demonstrated that C166-derived exosomes are an effective method for delivering reprogramming factors to cardiac fibroblasts as well as carrying a novel miRNA which enhances reprogramming efficacy.

Funding Information: Research conducted in these studies was supported by National Heart, Lung, and Blood Institute grant R01 HL131814-01A1 and as well as the Edna and Fred L. Mandel, Jr. Foundation.

Declaration of Interests: Conrad P. Hodgkinson and Victor J. Dzau are co-founders of Recardia Therapeutics. This company aims to translate miR combo to clinical applications.All other authors have nothing to declare.

Ethics Approval Statement: Experiments using animals were approved by the Duke University Division of Laboratory Animals (DLAR) and the Duke Institutional Animal Care and Use Committee (IACUC). In addition, all studies and procedures conformed to the NIH Guide for the Care and Use of Laboratory Animals.

Keywords: Reprogramming, Cardiac, miRNAs, Exosomes