Novel hydroxybutyl chitosan nanoparticles for siRNA delivery targeting tissue factor inhibits proliferation and induces apoptosis in human vascular smooth muscle cells

Chitosan, a polysaccharide isolated from shrimp and other crustacean shells, has been widely investigated for DNA and siRNA delivery. Despite substantial effort having been made to improve chitosan as a non-viral gene delivery vector, the application is severely limited by its poor solubility under physiological conditions. Hydroxybutyl chitosan (HBC), a modified chitosan, is soluble under neutral conditions. Tissue factor (TF) is involved in the pathogenesis of cardiovascular diseases by promoting thrombus formation and inducing the migration and proliferation of vascular smooth muscle cells. Targeting TF is an attractive therapeutic strategy for cardiovascular diseases. In the present study, the use of HBC for the transfer of TF-siRNAs into human umbilical vein smooth muscle cells (HUVSMCs) was investigated, and the effects of TF knockdown on cell proliferation and apoptosis were examined. HBC/siRNA nanoparticles were produced by mixing HBC and siRNA solutions with the assistance of tripolyphosphate buffer. The transfection efficiency with these nanoparticles was 74±2.5%, which was determined using a fluorescence-labeled siRNA under fluorescence microscopy. The delivery of HBC/TF-siRNA resulted in reductions in the production of cellular and soluble TF protein in HUVMSCs, which were measured using western blotting and enzyme-linked immunosorbent assay, respectively. TF knockdown led to inhibited cell proliferation, as assessed using a Cell Counting Kit-8 assay, and increased cell apoptosis, determined using Annexin V-fluorescein isothiocyanate staining. These findings suggested that HBC may be a promising vector for siRNA delivery, and that in vivo HBC/siRNA nanoparticle delivery targeting TF may be a potential option for the treatment of cardiovascular diseases, which warrants further investigation.