OBJECTIVETo investigate the penetrating ability of fusion protein PEP-1-EGFP with human umbilical vein endothelial cells.

METHODSTwo prokaryotic expression plasmids pET15b-EGFP and pET15b-PEP-1-EGFP were constructed and transformed into E. coli BL21 (DE3) to express EGFP and fusion protein PEP-1-EGFP, respectively. The expressed EGFP and PEP-1-EGFP were purified with Ni(2+) -resin affinity chromatography, and their capabilities of transduction into human umbilical vein endothelial cells were evaluated. The time- and dose-dependent transduction of the fusion protein PEP-1-EGFP and its stability in the human umbilical vein endothelial cells were observed. The toxicity of the fusion protein PEP-1-EGFP was detected by MTT method.

RESULTSEGFP failed to be transduced into human umbilical vein endothelial cells, whereas PEP-1-EGFP fusion protein was transduced into cells shortly in 5 minutes. Its transduction was time- and dose-dependent and the fluorescence in the cells were detected even 27 hours later. No cytotoxicity of the fusion protein PEP-1-EGFP to human umbilical vein endothelial cells was detected even when the dose reached up to 200 micromol/L.

CONCLUSIONPEP-1-EGFP fusion protein can efficiently transduce the target protein into human umbilical vein endothelial cells, which provides a basis for future researches on the transduction of antioxidant enzymes mediated by the cell-penetrating peptide, PEP-1, in ischemia-reperfusion injury therapy.