Fig. 6: Ppar activation rescues defective fatty acid utilization and normalizes the choline and phosphocholine levels in differentiated Chkb^−/− myocytes in culture.

A Representative kinetic graph of the fatty acid oxidation of primary Chkb^−/− myocytes at day 7 of differentiation. The cells were treated with or without ciprofibrate (50 μM), bezafibrate (500 μM) or fenofibrate (25 μM) in the medium 72 h prior to measurement. Values are means ± SEM; n = 4 for each group. Each experiment was repeated independently 3 times with similar results. Quantification of basal respiration and maximal respiration which quantifies maximal electron transport activity induced by the chemical uncoupler FCCP. Values are means ± SEM; For B, n = 12 (Chkb^+/+), n = 12 (Chkb^−/−), n = 12 (Chkb^−/− Bezafibrate), n = 12 (Chkb^−/− Fenofibrate), n = 12 (Chkb^−/− Cipofibrate) wells per group. One-way ANOVA with Tukey’s multiple comparison test, p < 0.0001. ##p < 0.01 vs Chkb^+/+ group. For C n = 9 (Chkb^+/+), n = 9 (Chkb^−/−), n = 12 (Chkb^−/− Bezafibrate), n = 12 (Chkb^−/− Fenofibrate) and n = 12 (Chkb^−/− Cipofibrate). One-way ANOVA with Tukey’s multiple comparison test, p < 0.0001. *p < 0.05, **p < 0.01, #p < 0.05 vs Chkb^+/+ group, ##p < 0.01 vs Chkb^+/+ group. D Representative kinetic graph of the fatty acid oxidation of primary Chkb^−/− myocytes at day 7 of differentiation. The cells were treated with or without specific pparb/d agonist GW501516 (2.5 μM) in the medium 72 h prior to measurement. Values are means ± SEM; For D, n = 4 (Chkb^+/+), n = 5 (Chkb^−/−) and n = 4 (Chkb^−/− GW501516) wells per group. Each experiment was repeated independently 3 times with similar results. E, F Quantification of basal respiration and maximal respiration which quantifies maximal electron transport activity induced by the chemical uncoupler FCCP. Values are means ± SEM; For E, n = 12 (Chkb^+/+), n = 15 (Chkb^−/−), n = 12 (Chkb^−/− GW501516). One-way ANOVA with Tukey’s multiple comparison test, p < 0.0001. **p < 0.01, ##p < 0.05 vs Chkb^+/+ group. RT-qPCR analysis of Chka gene expression in differentiated Chkb^+/+, Chkb^−/− and Chkb^−/− myocytes treated with or without Ciprofibrate 50 (μM) (G), GW501516 (2.5 μM) (H) or bezafibrate (500 μM) (I) in the medium for 48 h on day 4 of differentiation with or without choline (1 mM) supplementation. For G–I, n = 3 independent samples per group. One-way ANOVA with Tukey’s multiple comparison test, p < 0.0001. **P < 0.01. J–L Targeted metabolomic profiling of Chkb^+/+, Chkb^−/− and Chkb^−/− myocytes treated with bezafibrate (500 μM) for 48 h on day 4 of differentiation with or without choline (1 mM) supplementation. Ppar activation increases phosphocholine (p-Choline) level (K) and normalizes acylcarnitine (AcCa) level (L) in differentiated Chkb^−/− myocytes. Values are means ± SEM. For J and K, n = 6 samples for each group. One-way ANOVA with Tukey’s multiple comparison test. p < 0. 0001. Each experiment was repeated independently 3 times with similar results. For L, n = 15 AcCa species from 3 independent samples for each group. One-way ANOVA with Tukey’s multiple comparison test. P < 0. 0001. Each experiment was repeated independently 3 times with similar results. *p < 0.05 and **p < 0.01. Source data are provided as a Source Data file.