Expression,Modulation and adhesive function of a novel inducible adhesion molecule PTA1 on human endothelial cells
CHEN Li hua,JIN Bo quan, JIA Wei,XIE Xin, LIU Xue shong,OU YANG Wei ming Department of Immunology, Fourth Military Medical University, Xi'an 710033,Shaanxi Province, China
Aim To investigate the expression and regulation of inducible PTA1 on the human umbilical vein endothelial cells(HUVEC) and ECV304 cells and its adhesive role in the adhesion between endothelial cells and Jurkat cells. Methods Indirect fluorescent staining, FCM analysis and RT PCR were employed to detect the expression and regulation of PTA1 at the levels of PTA1 protein and PTA1mRNA. Na251CrO4 labeled resting or TPA activated Jurkat cells were added into HUVEC in the presence or absence of PTA1/Ig fusion protein to examine the adhesion effect. Results ①The expressions of PTA1 molecule and PTA1mRNA were very weak on resting HUVEC and ECV304 cells, whereas high level expression could be observed when these cells were stimulated by TNF αor LPS. After 8h stimulation with TNF αor 48h stimulation with LPS the expression of PTA1 protein reached its peak. ②The adhesion between TNF αactivated HUVEC and Jurkat cells was much higher than that between resting HUVEC and Jurkat cells. Similarly the adhesion between TPA activated Jurkat cells and HUVEC was higher than that between resting Jurkat cells and HUVEC. The binding activities between endothelial cells and Jurkat cells either in resting or in activated status could partly be blocked by the addition of PTA1/Ig fusion protein. Conclusion TNF αor LPS activated HUVEC and ECV304 cells can express high level PTA1 protein and PTA1mRNA,and PTA1 is involved in the adhesion between endothelial and Jurkat cells,suggesting that PTA1 is a novel inducible adhesion molecule on human endothelial cells.