Figure 4.

Nutrient conditions have a significant effect on galectin 3 secretion via O-GlcNAcylation. HeLa cells were grown in different concentrations of glucose for 48 h and the amount of galectin 3 secreted into the conditioned media was measured using and ELISA assay. HeLa cells grown in lower concentrations of glucose (blue) were found to secrete significantly more galectin 3 (A). Western blots of these HeLa cells grown under different glucose conditions shows a glucose dependent increase in O-GlcNAcylation corresponding to glucose concentration (B). HeLa cells were then grown in different concentrations of glucose with and without thiamet G treatment (OGA inhibitor, striped bars) for 48 h and the amount of galectin 3 secreted into the conditioned media was measured using and ELISA assay. Thiamet G treatment (striped bars) during these incubations leads to a significant partial ablation of the increased galectin 3 secretion observed at 0 g/l glucose (blue) (C). Western blots of these HeLa cells grown under different glucose conditions with or without Thiamet G treatment shows a glucose dependent increase in O-GlcNAcylation corresponding to glucose concentration and increase in O-GlcNAcylation corresponding to Thiamet G treatment (D). Galectin 3 secretion over 48 h was measured by ELISA assay from conditioned media from mouse embryonic fibroblasts from female WT or female OGA KO mice (red) (E). The nutrient-sensitive increase in galectin 3 secretion observed in WT MEFs is absent in OGA KO MEFs. At least three independent experiments were carried out with data expressed as mean ± S.D. (error bars). ∗ indicates a p < 0.05. ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001 in a one-way ANOVA with a Bonferroni posttest. OGA, O-GlcNAcase.