ABSTRACT
Objective To investigate the activation of T lymphocytes in human peripheral blood and the signaling molecules in protein kinase C/nuclear factor KB(PKC/NF-κB) pathway expressivity or activity changes in human peripheral blood mononuclear cells(PBMCs) exposed to coal-arsenic,to explore the role of PKC/NF-κB signal pathway in activation of T cells in human exposed to coal-arsenic. Methods Blood samples were collected from individuals who lived in arsenism area of coal-burning in Guizhou province, and were divided into asymptomatically exposed group (12),mild arsenism group (33),moderate arsenism group (34) and severe arscnism group (15) according to Diagnosis Standard for Endemic Arsenism (WS/T 211-2001). The individuals who lived in non-arsenism area were control group(27). The ratio of activated T ceils was analyzed by flow cytometry. DNA binding activity of NF-κB in PBMCs was evaluated by electrophoretic mobility shift assay(EMSA). The expression of PKCθ and phospho-PKCθ(pPKCθ) in PBMCs were detected with western blotting analysis. Results The ratio of activating T cells in asymptomatically exposed group[(21.76±15.31)%],mild arsenism group[(18.41±11.36)%],moderate arsenism group[(17.78±11.93)%]and severe arsenism group[(18.79±13.38)%]were all higher than that of control group[(3.19±2.12)%],the difference among all groups being statistically significant(F = 7.893,P < 0.05). DNA binding activity of PBMCs NF-κB in asymptomatically exposed group,mild arsenism group,moderate arsenism group and severe arsenism group(1.49±0.24,1.58±0.30,1.57±0.34,1.51±0.16) were higher than that of the control group(1.30±0.17),the difference being statistically sign/ficant(P < 0.05 or < 0.01). The expression of PBMCs pPKCθ in mild arsenism group,moderate arsenism group and severe arsenism group(0.64± 0.14,0.64±0.27,0.62±0.12) were all lower than that of the control group(0.93±0.20),the difference being statistically significant(P < 0.05). There were significant negative correlations between the expression of pPKCθ and the activity of NF-κB(r =-0.565,P < 0.01). There were significant positive correlations between the activity of NF-κB and the ratio of activating T cells(r = 0.546,P < 0.01). Conclusion Coal-arsenic enhances the DNA binding activity of NF-κB,reduces the expression of PBMCs pPKCθ in human PBMCs and up-regulates the activity of T cells. It suggests that the PKC/NF-κB signal might be one of transduction pathway via activating of T cells by coal-arsenic.
ABSTRACT
Objective To explore the influence of coal-arsenic exposure on human T cells proliferation and its mechanism.Methods Blood samples colleoted from individuals which lived in arsenism area of coal-burning type and non-arsenism area in Guizhou Province were divided into exposed group(17),mild(35),moderate(38) and severe arsenism group(19)and control group(35)according to Diagnosis Smndard for Endemic Arsenism (WS/T 211-2001).T cell stimulation index wag determined by methyl thiazolyl tetrazolium(MTT)colorimetric method.The intracellular Ca2+ exponential(IECa2+)in peripheral blood mononuclear cell(PBMC)was analyzed by Fho-3/AM dye and flow cytometry.DNA binding activity of actively T cells nuclear factor(NF-AT)in PBMC was evaluated by electrophoretie mobility shift assay(EMSA).Results Concanavalin A(ConA)stimulation decreased the T cells stimulation indexes in exposed group,mild,moderate and severe arsenism groups(1.315±0.962, 1.611±1.224,1.114±0.545,1.289±0.875)compared with control group(2.322±1.241),all the differences being statistically significant(P＜0.01).After stimulated by anti-CD3 monoclonal antibody(McAb),the T cells stimulation index in exposed group,mild,moderate and severe arsenism group(0.997±0.177,1.103±0.291,1.007±0.221, 0.957±0.205) were lower than that of control group(1.842±0.429,P ＜ 0.01 ). IECa2+ of PBMC after treated by anti-CD3 McAb in mild,moderate and severe arsenism group( 110.130±49.637,92.429±31.191,77.640± 35.372) were lower compared with control group(145.986±59.450,P ＜0.01 ). Moreover,IECa2+ in moderat and severe arsenism group were lower than exposed group(121.337±46.410,P ＜ 0.05). DNA binding activity of PBMC NF-AT in mild,moderate and severe arsenism group(1.354±0.446,1.290±0.291,1.159±0.411 ) were lowered than that of control group(1.722±0.291,P ＜ 0.01) and exposed group(1.611±0.294,P ＜ 0.05). Conclusions The coal-arsenic exposure can reduce the human T cells stimulation indexes,IECa2+ in PBMC and the DNA binding activity of NF-AT. It suggest that arsenic may suppress the proliferation ability of human T cells,which may be partly related to the influence of arsenic on T cell receptor(TCR)/CD3 signal transduetion pathway.