PD98059 and SB203580 respectively blocked the down-regulating effect of AGE-BSA on Cx43 protein (as detected by Western blotting and immunoconfocal microscopy) but not the effect on the gap-junction communication (by scrape loading). Note the relative expression levels of Cx43 in cells treated with AGE-BSA (500 μg/ml; 24 hours) were reversed from 62.3 ± 4.8% to 84.1 ± 4.4% by PD98059 (A) and from 60.5 ± 1.6% to 79.6 ± 2.9% by SB203580 (B), respectively. The results were further confirmed by immunoconfocal microscopy (C). The inhibition of gap-junction communication by AGE-BSA (500 μg/ml; 24 hours) was not rescued in the presence of PD98059 and SB203580 (D). *, p < 0.05 compared to the untreated cells. Images in (C) were obtained from the control group, cells treated with AGE-BSA, cells treated with AGE-BSA and PD98059, and cells treated with AGE-BSA and SB203580, respectively. Note that Cx43 gap junctions (red spots) were reversed near the level of the control group by PD98059 and SB203580. Blue label, nucleus. The concentrations of AGE-BSA and inhibitor used are indicated in the upper left of each image. All images are of the same magnification. Bar, 50 μm.
Wang et al. BMC Cell Biology 2011 12:19 doi:10.1186/1471-2121-12-19