Transduction efficacy of Tat-Cu,Zn-superoxide dismutase is enhanced by copper ion recovery of the fusion protein.
We previously reported that Tat-Cu,Zn-superoxide dismutase (Tat-SOD) can be directly transduced into mammalian cells across the lipid membrane barrier. To enhance the therapeutic potential of Tat-SOD for the treatment of various disorders that are related to this antioxidant enzyme, the transduction efficacy of Tat-SOD should be heightened. Therefore, we investigated whether copper ion recovery of the fusion protein could enhance the transduction potential of Tat-SOD in cultured HeLa cells. The results showed that the transduction potential of Tat-SOD was markedly enhanced by copper ions, and moderately increased by zinc ions. Compared with Tat-SOD, the Tat-SOD that recovered the copper ion (CR-Tat-SOD) achieved a significant increase in intracellular concentration and enzymatic activity. Therefore, CR-Tat-SOD was transduced into HeLa cells in a rapid saturation manner, but Tat-SOD was shown in a time-dependent manner. With the higher transduction efficacy of CR-Tat-SOD than that of Tat-SOD, the transduced CR-Tat-SOD significantly increased the viability of HeLa cells that were pretreated with paraquat, an intracellular superoxide anion generator. Although the mechanism of the enhanced transduction of Tat-SOD by copper ions is still unanswered, these results indicate that copper ions facilitate the transduction of SOD. These then significantly increase the biological effectiveness of this antioxidant enzyme.
Eum
Won Sik
WS
Department of Physiology, College of Medicine, Hallym University, Chunchon, Korea.
Choung
In Soon
IS
Kim
A Yeon
AY
Lee
Yong Je
YJ
Kang
Jung Hoon
JH
Park
Jinseu
J
Lee
Kil Soo
KS
Kwon
Hyeok Yil
HY
Choi
Soo Young
SY
D000975:Antioxidants / Q000378:metabolism; D002470:Cell Survival; D003300:Copper / Q000378:metabolism*; D015696:Gene Products, tat / Q000235:genetics*; D006367:HeLa Cells; D006801:Humans; D008670:Metals / Q000378:metabolism; D010269:Paraquat / Q000378:metabolism; D021381:Protein Transport; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism
D000975:Antioxidants; D015696:Gene Products, tat; D008670:Metals; D011993:Recombinant Fusion Proteins; D003300:Copper; D013482:Superoxide Dismutase; D010269:Paraquat