ABSTRACT
Objective To investigate the effect of human CD47 (hCD47) in inducing the immune tolerance of human macrophages to porcine endothelial cells. Methods The porcine iliac endothelial cell (PIEC) transfected with pCDH-hCD47-FLAG plasmid was assigned into the pCDH-hCD47 group, PIEC transfected with pCDH-FLAG empty vector plasmid was assigned into the pCDH group, PIEC transfected with hCD47-dN was assigned into the pCDH-hCD47-dN group and human umbilical vein endothelial cell (HUVEC) was assigned into the positive control group. The cells were co-cultured with human macrophages to detect and analyze the phosphorylation of signal regulatory protein α (SIRPα) and the killing effect of human macrophages on PIEC. Furthermore, porcine arteriae endothelial cell (PAEC) was isolated from GT－/－ and GT－/－/ hCD 47 gene editing pigs to analyze the phosphorylation of SIRPα and the killing effect of human macrophages on PAEC. Results The pCDH group cells could not induce the phosphorylation of SIRPα, whereas the pCDH-hCD47 group cells could activate the phosphorylation of SIRPα after 10 min co-culture with human macrophages, and the degree of phosphorylation of SIRPα was increased with the prolongation of the co-culture time. The pCDH-hCD47-dN group cells failed to activate the phosphorylation of SIRPα. Human macrophages exerted significant effect on killing the pCDH group cells. The pCDH-hCD47 group cells could evidently inhibit the killing effect of human macrophages (P < 0.05), whereas the pCDH-hCD47-dN cells failed to suppress the killing effect of human macrophages. GT－/－-PAEC could not activate the phosphorylation of SIRPα after co-culture with human macrophages. However, GT－/－/hCD47-PAEC significantly activated the phosphorylation of SIRPα after co-culture with human macrophages. Human macrophages exerted significant killing effect on GT－/－-PAEC, and GT－/－/hCD47-PAEC could obviously inhibit the killing effect of human macrophages (P < 0.05). Conclusions The expression of hCD47 in the porcine endothelial cells can inhibit the killing effect of human macrophages on endothelial cells by activating the phosphorylation of SIRPα.
ABSTRACT
Baerobic, spore forming, and rod-shaped bacterium. Anthrax spores are introduced into macrophage by phagocytosis and multiply after germination. The anthrax spores infected in macrophage produce lethal toxin eventually caused cell death. In this study, we analyzed apoptosis and cytokine TNF-alpha and IL-12 secretion after the infection of spores of B. anthracis Sterne in the murine macrophage RAW264.7 cells and in the primary human macrophages. In murine macrophage RAW264.7 cells infected by spore of B. anthracis Sterne, the cells were markedly changed in secretion of TNF-alpha (482~6,213 pg/ml) by lethal toxin, and induced apoptosis. In case of RAW264.7 cells infected by formalin-inactivated spores of B. anthracis, the cells were not able to produce lethal toxin, which released lower level concentration of TNF-alpha (7.7~97.2 pg/ml), and rarely induced apoptosis. When primary human macrophage cells infected with spores of B. anthracis Sterne, they secreted TNF-alpha (5~16 pg/ml), and induced apoptosis about 1% of total cells. We presented that inducing apoptosis by spores of B. anthracis Sterne capable of expressing lethal toxin is related with the secretion of TNF-alpha in murine macrophage RAW264.7 cells. These studies revealed that human and murine macrophages has affected differently by anthrax lethal toxin produced by spores of B. anthracis Sterne.
Subject(s)
Humans , Anthrax , Apoptosis , Bacillus anthracis , Bacillus , Cell Death , Germination , Interleukin-12 , Macrophages , Phagocytosis , Spores , Tumor Necrosis Factor-alphaABSTRACT
Objective To establish a glucocorticoid receptor knockdown model of human macrophage cell line U937 with RNA interference technique. Methods Two RNAi recombinant plasmids (named pSilencer 3.1-GR 1 and pSilencer 3.1-GR 2) targeting to GR gene were constructed. After RNAi recombinant plasmids were transfected into human macrophage cell line U937, the expressions of GR mRNA and GR protein were evaluated with RT-PCR and Western blotting respectively. The transcriptional activation function of GR was evaluated through the detection of relative luciferase activity after dexamethasone treatment. Results Two RNAi recombinant expression plamids were constructed and identified by sequencing. pSilencer 3.1-GR 2 transfection could inhibit not only GR mRNA and protein expressions, but also transcriptional activation function of GR specially; pSilencer 3.1-GR 1 transfection had no significant changes as compared to normal control. Conclusion A glucocorticoid receptor knockdown model has been established successfully, which offers a new method for the further research of GR biological functions.
ABSTRACT
Objective To investigate the expression of human macrophage metalloelastase(HME) both in gastric cancer cell lines and gastric cancer tissues,and to find the role of HME in gastric carcino genesis.Methods Fifty eight patients who were operated in our hospital during April to Aug.2003 were enrolled.The samples taken from cancer,paracancer or normal tissues of these patients and cancer cell lines(MGC-803,SGC-7901,AGS)were detected for HME protein and HME mRNA expressions by Western blot and immunohistochemistry,RT-PCR and fluorescence quantitative PCR,respectively. Results Both HME mRNA and HME protein expressions were found in all three gastric cancer cell lines.The expressions of HME mRNA and HME protein in gastric cancer tissues was increased signifi- cantly compared with that in normal tissues(P0.05).Conclusions The increased HME expression in gastric cancer tissures compared with normal tissue indicate that HME may be a potential tumor marker for gastric cancer.