Extended Data Fig. 4: Additional metabolomics analysis.
From: Salvage of ribose from uridine or RNA supports glycolysis in nutrient-limited conditions
(a) Steady-state abundance of representative intracellular metabolites from the pentose phosphate pathway (PPP) and glycolysis in sugar-free media complemented with 10 mM glucose, 10 mM galactose or 10 mM uridine, in the presence of 4mM L-glutamine and 10% dialyzed FBS (n = 3 replicate wells, P < 2.2 × 10−5, P < 8.1 × 10−4, P < 4.7 × 10−7, P < 1.4 × 10−4). Data are shown as mean ± SEM with two-sided t-test relative to control cells. (b) 13C5-uridine tracer analysis of liver and blood uridine 30 min after intraperitoneal injection in fed or overnight fasted mice with 0.4 g/kg 13C5-uridine (n = 3 replicate wells, P < 2.3 × 10−4, P < 2.9 × 10−4, P < 1.4 × 10−2, P < 9.3 × 10−5). Data are shown as mean ± SEM (c) 13C5-uridine tracer analysis of liver ribose-phosphate (ribose-P) and circulating lactate and glucose 30 min after intraperitoneal injection in overnight fasted and (d) in fed animals with 0.4 g/kg 13C5-uridine. Data are shown as mean ± SEM and are corrected for natural isotope abundance (n = 4 mice in each group). (e) 13C5-uridine tracer analysis of liver ribose-phosphate, blood lactate and blood glucose 30 min after intraperitoneal injection in fed mice with 0.4 g/kg 13C5-uridine shown as the percentage of 13C-labeled intermediate compared to the total pool. Data are shown as mean ± SEM and are corrected for natural isotope abundance (n = 4 mice). See also (f) qPCR determination in the liver of ad libitum fed mice, or fasted for 12 h or 24 h, with probes to Upp1, Upp2 and Hmgc2. Hmgc2 transcripts are expected to increase with fasting. Data are shown as mean ± SEM (n = 3 mice in each group).
