Targeted suppression of ALDH1A3 for endothelial beneficial management of restenosis after vascular surgery

Project Summary Angioplasty is commonly performed to press open occluded coronary and peripheral arteries. Unfortunately, this invasive procedure often induces smooth muscle cell dysfunction and intimal hyperplasia (IH) that re-narrows the vascular lumen, leading to recurrent disease. Mechanical stretching of the artery can cause injury to endo- thelial cells (ECs), leading to inflammation and thrombosis which further exacerbate IH. We previously found that elevated expression of ALDH1A3, known as a cytosolic metabolism coordinator, is present in human and rodent neointimal tissues, and that pharmacological inhibition of ALDH1A3 ameliorates IH in an angioplasty-induced animal model. Here we present new findings to suggest that molecular knockdown of ALDH1A3 enhances re- covery of ECs following angioplasty injury, via a novel nuclear action of ALDH1A3 on the transcriptional control of KFL2, a known master regulator of EC proliferation and inflammation. We find that siRNA knockdown of ALDH1A3 enhances EC scratch-wound healing in vitro, associated with upregulation of EC-protective genes (e.g. eNOS) and down-regulation of EC-detrimental (e.g. inflammatory) genes. ALDH1A3 forms a complex with the acetyltransferase p300 and pro-inflammatory transcription factor p65, and knockdown of ALDH1A3 reduces acetylation and stability of p65 and consequently p65’s negative impact on KLF2 expression in ECs. We have promising in vivo findings that targeted suppression of ALDH1A3 can protect EC function and mitigate IH in rats. Overall, our findings support the premise that ALDH1A3 knockdown may provide a novel EC-protective approach to IH mitigation. Toward translation, we have generated an injectable siRNA-loaded Biomimetic Torpedo – a capsule of neutrophil membranes hybridized with liposomes that enables wound-targeted delivery of the siRNA payload to the injured ECs. By resolving the EC-specific role of ALDH1A3 in EC impairment associated with IH and its nuclear action in regulating KLF2 function, we can advance the understanding of IH pathophysiology (Aim 1). By developing Biomimetic Torpedo for targeted delivery of siRNA against ALDH1A3, our work may lead to a stent-free, EC-protective new paradigm for post-angioplasty management of IH (Aim 2).