FGFR Signaling Coordinates the Balance Between Glycolysis and Fatty Acid β-Oxidation in Lymphatic Endothelial Cells

The balance between glycolysis and oxidative phosphorylation is believed to be critical for maintaining cellular bioenergetics, yet the regulation of such balance in lymphatic endothelial cells (LECs) remains unclear. Here we found that chemical inhibition of fibroblast growth factor receptor (FGFR) activity or knockdown of FGFR1, which has been shown to suppress glycolysis and consequently ATP production, induces substantial upregulation of fatty acid {beta}-oxidation (FAO), but not glucose oxidation or glutamine oxidation in LECs. Mechanistically, blockade of FGFR-AKT signaling promotes the expression of CPT1A, a rate-limiting enzyme of FAO, in a PPAR-dependent manner. Metabolic analysis further showed that CPT1A depletion impairs ATP generation in FGFR1-deficient rather than wild-type LECs. This result suggests that FAO, which makes a minor contribution to cellular energy under normal conditions, can compensate for energy deficiency caused by FGFR inhibition. Consequently, CPT1A silencing potentiates the effect of FGFR1 knockdown on impeding LEC proliferation and migration. Collectively, our study identified an FGFR-regulated metabolic balance that is important for LEC growth.