ROLE OF FATTY ACID ß-OXIDATION IN LYMPHANGIOGENESIS. Homo sapiens

Lymphatic vessels are involved in fluid drainage and are critical for health. To date, only genetic signaling pathways have been implicated in lymphatic development, and a role for metabolism has not been described. Here, we report that transcription factor Prox1 increases fatty acid ß-oxidation (FAO) through upregulation of CPT1a, a rate-controlling step of FAO. Lymphatic endothelial cells (LECs) oxidize fatty acids to proliferate and migrate. By providing acetyl-CoA, FAO is also critical for the maintenance of differentiated LECs through the regulation of histone acetylation of key lymphangiogenic genes. Loss of CPT1a in LEC precursors causes lymphatic defects in vivo, while restoration of acetyl-CoA by supplementing acetate to replenish cellular acetyl-CoA levels rescues this process. Overall design: We have profiled Prox1 binding sites in programmed lymphatic endothelial cells using ChIP-seq by overexpressing a FLAG-tagged PROX1 or a normal PROX1 (2 replicates each). We have also profiled the overlap of PROX1 binding with p300 binding sites in these cells as determined using ChIP-seq (2 replicates). Finally, we have investigated changes in acetylation of histone 3 lysine 9 (H3K9ac) in response to Prox1 overexpression and Cpt1a knockdown (3 replicates)