Effect of fusion protein TAT and heme oxygenase-1 on liver sinusoidal endothelial cells apoptosis during preservation injury

Background Proteins or peptides can be directly transferred into cells when covalently linked to protein transduction domains （PTDs）. TAT is one of the most widely studied PTDs. The effect of fusion protein TAT and heme oxygenase-1 （HO-1） on liver sinusoidal endothelial cells （SECs） apoptosis during cold storage is unknown. The present study aimed to determine whether fusion protein TAT-HO-1 would transduce efficiently into liver during cold storage, and, if so, to determine whether TAT-HO-1 would attenuate SECs apoptosis during preservation injury in rat. Methods Livers of Sprague-Dawley rats were harvested and randomly assigned to group 1 （HTK solution） and group 2 （HTK solution containing TAT-HO-1 fusion protein） according to the type of the preservation solution. The transduction efficiency of TAT-HO-1 was examined and the impairment of SECs was assessed during the period of cold storage followed by 1 hour of reperfusion. Results TAT-HO-1 can transduce efficiently into liver during cold storage. A significantly lower apoptotic index of SECs was observed in group 2, at 6, 12 and 18 hours of cold storage after 1 hour reperfusion, when compared with group 1. TAT-HO-1 reduced HA and ET levels in liver at each time point. Both Bcl-2 and Bax protein were expressed in hepatocytes and SECs at the periphery of the sinusoidal space. Moreover, higher Bcl-2 expression and lower Bax expression were observed in group 2. Conclusions TAT-HO-1 can transduce efficiently into rat livers and shows a protective effect on SECs by attenuating apoptosis during cold ischemia/reperfusion injury. Protein transduction will be a novel therapeutic strategy to reduce the risk of preservation injury in liver transplantation.

Differential effects of recombinant fusion proteins TAT-OCT4 and TAT-NANOG on adult human fibroblasts

OCT4 and NANOG are two important tran-scription factors for maintaining the pluripotency and self-renewal abilities of embryonic stem(ES)cells.Meanwhile they play key roles in the induced pluripotent stem(iPS)cells.In this study,recombinant transcript factors TAT-NANOG and TAT-OCT4,which contained a fused powerful protein transduction domain(PTD)TAT from human immunodeficiency virus(HIV),were produced.Each fusion protein could be transported into human adultfibroblasts(HAF)successfully and activated the endogen-ous transcription of both nanog and oct4.Our study revealed the inter-regulation and autoregulation abilities of solo oct4 or nanog in the process of iPS cell reprogram-ming.Meanwhile the transduction of TAT-NANOG could accelerate the growth rate of HAF cells,and the key cell cycle regulator cdc25a was up-regulated.Thus cdc25a may be involved in the regulation of cell growth by NANOG.In addition,the TAT fusion protein technology provided a novel way to improve cell growth that is more controllable and safer.