Abstract: Abstract: Objective To identify the expression of sphingosine-1-phosphate receptor (S1PR) subtypes, C-myc and His tag proteins of human umbilical vein endothelial fusion cell line, EA.hy926 and human umbilical vein endothelial cells(HUVEC), CRL-1730 for studying the function of apolipoprotein M (ApoM)-S1P axis. Methods Two kinds of cells (EA.hy926 and CRL-1730) were cultured to reach the density of 60%-70% in vitro. Immunofluorescence technique was employed to investigate the expressions of coagulation factor Ⅷ (FⅧ), ApoM, S1PR1-S1PR5, C-myc and His tag proteins. Results (1) Two kinds of cells both expressed FⅧ and ApoM. FⅧ presented scattered particle distribution in CRL-1730,while uniform distribution in EA.hy926. However, ApoM was strongly expressed and widely distributed in cytoplasm of twokinds of cells. (2) S1PR1-3 can be detected on their membrane other than S1PR4 and S1PR5. S1PR1 was highly expressed but S1PR2 and S1PR3 were in a low level expression. (3) Two kinds of cells both expressed C-myc and His tag proteins in cytoplasm. Conclusion Two kinds of cells have the properties of endothelial cells and can express FⅧ, ApoM, C-myc and His tag proteins. It is not suitable for choosing C-myc and/or His tag–conjugated recombinant ApoM to study the fuction of ApoM-S1P axis with these two kinds of cells.

Key words: endothelial cells, sphingosine-1-phosphate receptor, apolipoprotein M, coagulation factor Ⅷ, proto-onco? gene proteins c-myc, His tag protein