Transfection of human hepatic stimulator substance gene could protect BEL-7402 cells against hepatotoxins / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate protective effects of hHSS transfection against CCl4 or H2O2.</p><p><b>METHODS</b>cDNA coding for hHSS was constructed into eukaryotic vector of pcDNA3.1 and transfected into BEL-7402 hepatoma cells. The expression of hHSS was analyzed with Northern blot.</p><p><b>RESULTS</b>The growth of the hepatoma cells was remarkably enhanced 24 to 144h after hHSS gene transfection, which suggesting hHSS gene expression could stimulate cells activity. Meantime, incubation of both wild-type and vector-transfected as well as hHSS-transfected cells with CCl4 or H2O2 resulted in severe damage as marked by cell mortality and the rate of apoptosis. However, it appeared that the transfection of hHSS enabled the hepatoma cells to raise obvious resistance against CCl4 and H2O2 injury. Compared the vector cells to the vector-transfected cells, apoptosis ratio were (32.44+/-0.52)% and (25.60+/-0.66)% in which treated with CCl4, while (47.78+/-0.45)% and (37.40+/-0.69)% in which treated with H2O2, t value is 16.82 and 25.20, P<0.01. MAPK phosphorylation was also activated after HSS transfected.</p><p><b>CONCLUSION</b>The function of hHSS gene expression could be related to proliferation of cell and protection against free radical damage.</p>

Prokaryotic expression and purification of human hepatic stimulator substance / 生理学报

To explore the possibility of prokaryotic expression of human hepatic stimulator substance (hHSS), hHSS gene was inserted in the downstream of glutathion S-transferase (GST) in a pET-42a expression vector and recombinant GST-hHSS fusion protein was expressed under IPTG induction in BL-21(DE3) cells. The recombinant HSS was purified with His.Tag affinity chromatography, and its bioactivity was analyzed. The results showed that GST-hHSS fusion protein was expressed both as a soluble or a inclusive body in bacterial cytosol. The soluble GST-hHSS expression reached up to 30% of the whole soluble protein of bacteria as determined by densitometry. The cleavage of GST-hHSS fusion protein with Factor Xa produced two fragments of the protein, which sized 33 and 15 kD, respectively. The molecular weight of recombinant HSS protein was identical to theoretical deduction based on the DNA sequences. The protein homology of 15 kD hHSS could be efficiently eluted out after Factor Xa cleavage. It is further indicated that the recombinant hHSS is able to proliferate hepatoma cells of BEL-7402 in the preliminary experiments.