Fig. 1

Cx43 expressed on monocytes modulates U937-HUVECs adhesion via ATP release. a Gap 27 and 18-α-GA induced no cytotoxicity in U937 monocytes (n = 5). Cell vitality is detected using cell counting kit-8 kit assays. The data of absorbance are normalized to control. b Gap 27 and 18-α-GA have no effects on Cx43 expression on U937 monocytes (n = 4). Cx43 expression is detected by western blotting. The gray values of blots are normalized to control. c U937-HUVECs adhesion is increased when U937 monocytes are pre-treated with Gap 27 and 18-α-GA (n = 4, *P < 0.05 vs control). U937-HUVECs adhesion is detected by adhesion assays. The data of adhesion fraction are normalized to control. d ATP release from U937 monocytes is reduced when U937 monocytes are pre-treated with Gap 27 and 18-α-GA (n = 6, *P < 0.05 vs control). ATP release is detected with ATP bioluminescence assay kits. The intensity of bioluminescence is normalized to control. e The ADO content is reduced when U937 monocytes are pre-treated with Gap 27 and 18-α-GA (n = 6, *P < 0.05 vs control). f The ADO content is reduced when U937 monocytes are pre-treated with APCP (n = 5, *P < 0.05 vs control). The ADO content is detected using related ELISA kits. The data of absorbance are normalized to control. g U937-HUVECs adhesion is increased when U937 monocytes are pre-treated with APCP (n = 5, *P < 0.05 vs control). h Application of exogenous ATP and ADO reduces U937-HUVECs adhesion increase provoked by 18-α-GA and Gap 27 (n = 5, *P < 0.05 vs control; # P < 0.05). U937-HUVECs adhesion is detected by parachute dye-coupling assays. The data of adhesion fraction are normalized to control. Gap 27: 300 μM, for 1 h; 18-α-GA: 50 μM, for 1 h; APCP: 300 μM, for 1 h; exogenous ATP: 200 μM, for 1 h; exogenous ADO: 100 μM, for 1 h. ADO, adenosine; APCP, α, β-methylene ADP; HUVEC, human umbilical vein endothelial cell. All experiments are conducted in the presence of TNF-α. All data are presented as mean ± S.D.. Multiple comparisons among groups are performed using repeated-measures one-way analyses of variance, followed by Tukey post hoc comparisons