VCAM-1 targeted nanocarriers of shRNA-Smad3 mitigate endothelial-to-mesenchymal transition triggered by high glucose concentrations and osteogenic factors in valvular endothelial cells

Abstract

Endothelial to mesenchymal transition (EndMT) of valvular endothelial cells (VEC) is a key process in the development and progression of calcific aortic valve disease (CAVD). High expression of the Smad3 transcription factor is crucial in the transition process. We hypothesize that silencing Smad3 could hinder EndMT and provide a novel treatment for CAVD. We aimed at developing nanoparticles encapsulating short-hairpin (sh)RNA sequences specific for Smad3 targeted to the aortic valve. We synthesized VCAM-1-targeted lipopolyplexes encapsulating shRNA-Smad3 plasmid (V-LPP/shSmad3) and investigated their potential to reduce the EndMT of human VEC. VEC incubation in a medium containing high glucose concentrations and osteogenic factors (HGOM) triggers EndMT and increased expression of Smad3. Exposed to lipopolyplexes, VEC took up efficiently the V-LPP/shSmad3. The latter reduced the EndMT process in VEC exposed to HGOM by downregulating the expression of αSMA and S100A4 mesenchymal markers and increasing the expression of the CD31 endothelial marker. In vivo, V-LPP/shSmad3 accumulated in the aortic root and aorta of a murine model of atherosclerosis complicated with diabetes, without affecting the liver and kidney function. The results suggest that targeting activated VEC with lipopolyplexes to silence Smad3 could be an effective, novel treatment for CAVD mediated by the EndMT process.

Keywords: Calcific aortic valve disease; Endothelial-to-mesenchymal transition; Nano; Smad3; VCAM-1; Valvular endothelial cells.