Epicardial cell transfection with cationic polymeric nanocomplexes

Abstract

Paracrine signalling has been shown to contribute to heart regeneration after myocardial infarction (MI). As an important signalling regulatory centre, the epicardium is crucial for the heart development. Moreover, it is re-activated after MI, indicating its involvement in the response to this injury. This project aims to accomplish in situ transfection of the epicardium to stimulate the regenerative signalling pathways after MI. Here an in vitro proof of concept of epicardial cell transfection with nanocomplexes is presented. pABOL polyplexes, resulting from complexation of a bioreducible polymer with a GFP gene plasmid (pCAG-GFP), were able to transfect epicardial cells when added in suspension to the culture. The pCAG-GFP-pABOL polyplexes formulation was the most suitable when compared to Lipofectamine, Fugene or naked plasmid, revealing 45.9±9.7% of cell viability and 39.4±6.4% of transfection efficiency. Moreover, the freeze-drying of the pABOL polyplexes was tested. pABOL polyplexes formed in water and in the different sugar/surfactants HEPES buffers. The ζ-potential of these polyplexes ranged between +20 and +30mV. After the freeze-drying, pABOL polyplexes only maintained their transfection activity when formed in sugar-containing buffers. These preliminary results indicate for the first time the advantage of using pABOL polymer in comparison with standard transfection reagents for epicardial cells transfection and the possibility of retaining transfection activity of pABOL polyplexes when freeze-dried. Our final aim is to use nanoneedles, which can transfer substances to the epicardial layer alone, to deliver these polyplexes.