From single to a dual-gene delivery nanosystem: coordinated expression matters for boosting the neovascularization in vivo.

In the past decade, the development of gene carriers has been key in enhancing gene therapy. Gene therapy is associated with not only the delivery process but also gene expression as a prominent role. Herein, for the purpose of achieving a novel breakthrough in gene therapy, we creatively proposed a "strengthened gene expression" idea beyond the range of improving the gene carrier. We constructed three types of gene delivery systems, namely, single-pZNF580 delivery system, single-pVEGF165 delivery system, and dual-gene delivery system. These systems possessed approximate same sizes (∼120 nm) and zeta potentials (∼+20 mV), which indicated negligible differences in their cellular uptake. Interestingly, we found that the gene expression of dual-gene groups significantly increased at the level of both mRNA and protein at least 2 times and 1.5 times as high as single-gene groups, respectively. This "1 + 1 > 2" expression effect benefited from the coordinated expression of the angiogenesis-related genes of ZNF580 and VEGF165. Furthermore, the coordinated effect was also confirmed in HUVEC activities such as an obviously enhanced proliferation and migration of the dual-gene group. Rationally, we further evaluated the effects of coordinated interactions on neovascularization. We observed that the statistic tube number of dual-gene groups was approximately 1.44 times as high as that of single-gene groups. More importantly, this enhanced angiogenesis induced by the coordinated expression was also demonstrated in an in vivo environment. Therefore, we believed that the enhanced gene therapy via the gene expression pathway could provide a creative viewpoint for the design of gene delivery system and therapy.