A branched TAT cell-penetrating peptide as a novel delivery carrier for the efficient gene transfection

Abstract

Background: Cell penetrating peptides (CPPs) as one class of non-viral vectors, have been widely explored as a delivery tool due to their cell-penetrating capability with low cytotoxicity. However, CPPs have reported to have low gene transfection efficiency mainly due to the fact that DNA is larger than other biomolecules. On the other hand, the conventional linear CPPs are unstable for constructing the DNA complexes with it. Thus, here we designed a branched CPP using disulfide bridges based on the linear TAT peptide, to enhance the gene delivery efficiency in a better way. Results: The branched TAT (BTAT) was synthesized by the DMSO oxidation method and showed high-molecularweight about 294 kDa. The resulting BTAT was complexed with plasmid green fluorescence protein (pGFP) gene at various N/P ratios. The gene transfection efficiency was assessed on HeLa cells after treating with BTAT/pGFP complexes, showed high gene transfection efficiency as conformed by flowcytometry followed by confocal laser scanning microscopy (CLSM) visualization. Conclusion: The novel BTAT/pGFP complex exhibited significantly higher stability and redox cleavability by reducing agent. In addition, BTAT showed higher transfection efficiency approximately 40-fold than those of the TAT and mTAT complexes. Our primary experiments demonstrated the potential of BTAT as a suitable candidate for gene delivery and it could be applied for various types of gene delivery platforms. Abbreviations: AAS, Antibiotic antimycotic solution; BTAT, Branched TAT; CPPs, Cell penetrating peptides; DMEM, Dulbecco’s Modified Eagle’s Medium; DMSO, Dimethyl sulfoxide; FACS, Fluorescence-activated cell sorting; FBS, Fetal bovine serum; GSH, Glutathione; HEPES, 2-[4-(2-hydroxyethyl) piperazin-1-yl] ethanesulfonic acid; mTAT, Modified TAT; PEI, Poly (ethyleneimine), CLSM, confocal laser scanning microscope; pGFP, Plasmid green fluorescence protein; TEM, Transmission electron microscopy