| Objective:Signal transducer and activator of transcrip tion1(STAT1) was the first transcription factor which was founded i n STAT family and was necessary in innate immunity.STAT1 was a ctivated by Interferon-γ(IFN-γ) and other cytokines through the Janu s kinases-signal transducers and activators of transcription(JAK-STAT) pathway.Activated STAT1 induce the expression of target genes and involve in transduction mediated by cytokine signal,leading to airwa y inflammation and airway hyper responsiveness.Airway inflammatio n and airway hyper responsiveness was correlated with signaling pat hway of STAT1 abnormalities.Intercellular Adhesion Molecule-1(ICA M-1),one of the members in immunoglobulin super-protein family,w as an acute response protein.It may increase the eosinophils infiltrati on and airway hyperresponsiveness.Activated STATI in the nucleus,c ombining with co-activators such as transcription CBP P300 and SP I,may increase the expression of ICAM1 protein.RNA interference(R NAi) was applied in this study to explore the effect of STATI siR NA on Human bronchial epithelial cells by the detection of the se mi-quantitation of STAT1 and ICAM1 protein.Methods:Human bro nchial epithelial cells(16HBE) were cultured and divided into six gr oups:(1)IFN-γgroup:the cells were stimulated by IFN-γ30min;(2)no rmal cells;(3)pG-HK 48h group:IFN-γstimulated cells were transfect ed by pG-HK after 48h;(4)pGSTAT1 48h group:IFN-γstimulated cel ls were transfected by pGSTAT1 after 48h; (5)pGSTAT1 24h group: IFN-y stimulated cells were transfected by pGSTAT1 after 24h;(6) p GSTAT1 72h group:IFN-γstimulated cells were transfected by pGS TAT1 after 72h. The(4) (5)(6)groups were observed by microscope and fluorescence microscope respectively; The total cellular protein of these groups were extracted respectively.STAT1 and ICAM1 prote in expression was detected by the way of Western blotting.Relative gray was anaylyzed by Quantity one software and the datas were a nalyzed by SPSS software.Results:16HBE cells transfected bySTAT 1 siRNA was normal,The transfection efficiency was as high as 58. 21% in the pGSTATl 48h group.Relative content of STAT1 protein in IFN-y stimulated cells 30min group was significantly higher than the normal group(P<0.05),The difference with IFN-γstimulated cells 30min group and the pGHK group was no significant(P=0.384),STA T1 protein levels was reduced in pGSTAT1 48h group,relative conte nt ofSTAT1 was significantly lower than the pG-HK group(P<0.05). Difference with pGSTAT1 group and IFN-γstimulated cells 30min group was significantly(P<0.05),compared with normal group(P<0.0 5);Relative content of ICAM1 in IFN-γ30min group was significant ly higher than normal cells group(P<0.05),IFN-γgroup and pGHK group was no significantly diffrence(P=0.754).Expression of ICAM1 protein was reduced in pGSTAT1 48h group,relative content of ICA M1 protein was significantly lower than the pG-HK group(P<0.05). Difference with pGSTAT1 group and IFN-y group was significantly (P<0.05),compared with normal group(P>0.05);STAT1 and ICAM1 were measured respectively in cells transfected by pGSTAT1 after 2 4h 48h and 72h.A positive correlation between the two proteins wa s showed by linear correlation analysis(r=0.941,P<0.05).Conclusion: 1.Human airway epithelial cells could be effectively transfected by STAT1 targeting recombinant plasmid previously constructed in our laboratory; 2.STAT1 protein expression can be increased by IFN-γstimulation 30min in 16HBE cells;3,pGenesil-shRNA-STAT1 can dec rease the protein expression of STAT1 and ICAM1;4.STAT1 and IC AM1 protein expression was positively correlated.STAT1 may partici pate in controlling the protein expression of ICAM1.
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