ShRNAmediated knockdown of CD200 using the selfassembled nanoparticleforming derivative of polyethylenimine

Objective(s): ShRNAmediated silencing strategy is considered to be a potent therapeutic approach. The present study aimed to assess the ability of the previously prepared polyethylenimine (PEI) derivative for the shRNA knockdown of the CD200 gene on the cells obtained from the patients with chronic lymphocytic leukemia (CLL). Materials and Methods: Since there are several investigations regarding the role of CD200 overexpression in the progression of several malignancies (e.g., CLL), polyplexes were prepared using succinylated PEI and the plasmid encoding antiCD200 shRNA. The ability of the nanoparticles for CD200 silencing at the levels of protein and mRNA, as well as the apoptotic effects induced by unmodified PEI and its derivative, were evaluated. Results: Conjugation of succinic acid using the primary amines of PEI reduced the cellinduced toxicity of the polymer. Under such circumstances, 92.1% of the cells remained alive after treatment with the nanoparticles based on modified PEI. In addition, CD200 knockdown evaluations demonstrated a 50% reduction in the expression of the gene in the samples obtained from patients with CLL, while using the same formulation on the cells obtained from healthy donors decreased the CD200+ cells up to 10%. The results of CD200 silencing at the mRNA level revealed that the shRNA formulation could reduce the CD200 level in the cells of the patients by 3.26.06fold relative to the cells transfected with noneffective, scrambled shRNA. Conclusion: Our findings supported the application of succinylated PEI for the downregulation of the CD200 gene in the upcoming attempts to develop nanocarriers for gene therapy.