Angiopep-2-mediated delivery of human manganese superoxide dismutase in brain endothelial cells and its protective effect against oxidative stress

Abstract

© Springer Science+Business Media 2014. Oxidative stress has been considered as the leading cause of blood-brain barrier disruption which implicates many neurological disorders. Manganese superoxide dismutase (MnSOD or SOD2) is one of the crucial antioxidant enzymes that can provide substantial protection against oxidative damage. However, the therapeutic effect of the enzyme in such neurological diseases is limited due to poor transduction into brain microvascular endothelial cells. In the present study, a fusion protein of human SOD2 and a brain targeting peptide,Angiopep-2 (AP-2), was generated by genetic engineering. The SOD2-AP-2 and control SOD2 were successfully expressed in Escherichia coli and purified using immobilized metal affinity chromatography. Purified SOD2-AP-2 exhibited 1,090 μ/mg of specific SOD activity, which retained a significant activity in the same order of magnitude as that of native SOD2. The in vitro transduction demonstrated that 1 μM of SOD2-AP-2 delivered efficiently to immortalized mouse brain endothelial cell line within 30 min whereas, control SOD2 did not. Moreover, pretreatment with 50 units of SOD2-AP-2 for 1 h could significantly protect cells against paraquat up to 2 mM but control SOD2 pretreatment did not showa protective effect. Taken together, our findings pave the way for SOD2-AP-2 to be a potential therapeutic candidate for neurological diseases.