Figure 2. Glutamine deprivation causes metabolic reprogramming to inhibit glycolysis.

(A–C) Primary murine chondrocytes were cultured in media containing 4 mM glutamine or 0 mM glutamine for 24 hr. Cells were then treated with IL-1β (10 ng/mL) for 24 hr. Gene expression of G6pd2, Eno1, and Ldha was measured by quantitative PCR from n=6 replicates. One-way ANOVA was performed followed by Tukey’s multiple comparisons test. A: *p=0.0242, ****p<0.0001, B: ****p<0.0001, and C: ****p<0.0001. (D–K) Under similar conditions, metabolite levels were measured by Liquid chromatography–mass spectrometry (LC-MS) with n=3 replicates. One-way ANOVA was performed followed by Tukey’s multiple comparisons test. D: ***p=0.0003, E:***p=0.0006, F: p>0.05, G: p>0.05, H:*p=0.036, I: **p=0.0012, J:**p=0.0079, and K: **p=0.009.

Figure 2—figure supplement 1. Glutamine deprivation causes metabolic reprogramming to inhibit glycolysis.

(A–E) Primary murine chondrocytes were cultured in media containing 4 mM glutamine or 0 mM glutamine for 24 hr. Cells were then treated with IL-1β (10 ng/mL) for 24 hr. Gene expression of Gls, Got2, Idh2, Mdh, and Sdha was measured by quantitative PCR (qPCR) from n=6 replicates. One-way ANOVA was performed followed by Tukey’s multiple comparisons test. A: **p=0.0085 and ***p<0.0004; B: **p=0.0011; C: ****p<0.0001 and ***p=0.0003; D:*p=0.036; E:***p=0.0005. (F) Under similar conditions, supernatant was collected, and lactic acid was measured. One-way ANOVA was performed followed by Tukey’s multiple comparisons test. ****p<0.0001. (G) Gene expression of Psat1 was measured under similar conditions by qPCR. One-way ANOVA was performed followed by Tukey’s multiple comparisons test. ***p=0.0006.