The essential role of fibronectin for cardiac progenitor cells mediated repairs following myocardial infarction

Abstract

Cardiac progenitor Cells (CPCs) therapy in the treatment of myocardial infarction or heart failure has achieved modest success due to poor cell viability in the diseased microenvironment after transplantation. Engineering CPCs with biodegradable matrix holds promising prospects in improving cell retention and enhancing tolerance against death under harsh conditions. Recent studies demonstrate that the fibronectin (Fn) is one important component of extracellular matrix for heart development and is essential for myocardial repair after myocardial infarction. In this study, we aimed to determine whether in vivo tissue engineered cardiac progenitor cells with fibronectin could enhance their cardioprotective effects following myocardial infarction. In Chapter 3, we derived NKX2.5 positive cardiac progenitor cells from mouse embryonic stem cells in which GFP-reporter was knocked in at the end of Nkx2.5 locus. We characterized biomarkers and differentiation potential of NKX2.5-GFP CPCs. Purified NKX2.5-GFP CPCs were expanded for transplantation. In Chapter 4, CPCs were labeled with GFP virus vector, and transplanted into mice heart with or without Fn following myocardial infarction. The transplantation of CPCs with Fn remarkably improved cardiac functions and reduced infarct size, compared to cardiac progenitor cells injection only. Compared with solely CPC injection, employing Fn resulted in more cardiac progenitor cells survival following transplantation. The combining usage of Fn with CPCs injection increased cell mobility and resistance to apoptosis under hypoxic conditions. The combination of Fn and CPCs also recruited more endogenous c-kit positive progenitor cells migrating to infarcted zone. In Chapter 5, molecular mechanisms of Fn promoting CPCs survival and resisting apoptosis were explored. In vitro studies revealed that Fn can effectively enhance adhension of CPCs through binding to CPC surface receptor integrin α5β1. Fn also stimulated CPCs proliferation. In addition, under apoptosis stimulation, Fn proteced CPCs against apoptosis which was associated with activation of PI3K/Akt /Bcl pathway. These findings collectively suggest engineering cardiac progenitor cells with fibronectin enhances the effectiveness of stem cells therapy following myocardial infarction through potentiating cells survival and revitalizing cardiac repair and regeneration. The combination fibronectin and cardiac progenitor cells is more efficient than stem cells transplantation only, providing a potential solution for developing effective stem cell therapy in treating myocardial diseases.