Figure 6.

Role of glutamine and glucose in the secretome of ASC. ASC were cultivated for 72 h in fresh culture medium containing pyruvate to reach confluency. For additional 24 h of culture, the medium was replaced by pyruvate-free medium adapted to metabolomics analyses and supplemented with 0, 5, or 25 mM glucose in the presence of 0, 0.5, or 4 mM glutamine as indicated in the figure. Concentrations in culture supernatants were measured by ¹H-NMR. Results (mean ± SEM; n = 3) are the difference between concentrations in cell culture supernatants and the concentration in the initial medium placed in the same conditions (control). Values were not normalized to the cell number. Negative values represent metabolite consumptions and positive values the secretions at concentrations above the control. Results for S-ASC and V-ASC are represented back to back in the figures. (a) The glycolysis pathway is evidenced by monitoring glucose uptake and lactate secretion. (b) Pyruvate, citrate, and alanine secretions and uptakes. (c) The glutaminolysis pathway is evidenced by monitoring glutamine uptake and glutamate secretion. Statistics are from the one-way ANOVA test followed by Tukey's multiple comparison test: ^∗ p < 0.05, ^∗∗ p < 0.01, and ^∗∗∗ p < 0.001 and comparison of the partially depleted medium conditions with the complete medium condition (25 mM glucose and 4 mM glutamine). In (b) and (c), values for pyruvate and glutamate concentrations in glutamine-free conditions are represented but too low to be visible at the scale of these figures.