Fig. 4.

ERK1/2-dependent downstream signalling and cellular responses are regulated by CO₂ in ECs. a Increased expression of ICAM-1 and phosphorylation of MSK1 at T581 and NFkB p65 at S276 and S536 in response to 100 μM H₂O₂ were abrogated by treatment with 10% CO₂ (11 min, 4 times, 3-h interval). b The expression of HIF-1α and ICAM-1 were induced by 40 ng/ml RBD and could be decreased by 10% CO₂ in ECs (4 incubations, 11 min, 3-h interval). c The phosphorylation of NFkB p65 at S276 was increased in response to RBD, TNFα and IFNγ combination and could be decreased by 10% CO₂ (4 incubations, 11 min, 3-h interval) in ECs. d–e H₂O₂-induced (d) and RBD-triggered (e) production of IL-6 by ECs was diminished by 10% CO₂ (11 min, 3-h interval). The level of IL-6 secreted into the cell culture supernatant was determined by ELISA. Dimeric intracellular IL-6 was visualised by immunoblotting with an anti-IL-6 antibody, and the expression of this form of IL-6 was normalised to the signal obtained with an anti-GAPDH antibody. f CO₂ at a concentration of 9–12% inhibited the production of IL-6 which was induced by RBD, TNFα and IFNγ combination. IL-6 production was measured by ELISA. The results of three biological replications are presented as the mean ± SD