The Role of Mitochondrial Activity in the Differentiation of Human Embryonic Stem Cells (ESCs)

Abstract

IntroductionLittle is known about the role of metabolic pathways in regulating stem cell function and fate. We hypothesized that ESCs primarily use non‐mitochondrial glycolytic metabolism to avoid the production of ROS (reactive oxygen species) and promote their self‐renewal potential.MethodsWe studied metabolic gene expression and mitochondrial oxygen consumption in NIH‐approved WA01 human ESCs, adult human aortic smooth muscle cells and spontaneously differentiated ESCs. Mitochondrial membrane potential (ΨΔm) was assessed with the potentiometric dye JC1.ResultsThe expression of the mitochondrial biogenesis transcription factor PGC1a was significantly higher in ESCs when compared to mature vascular cells. ESCs had 16.29±3.94 fold (P<0.05 vs AoSMCs) higher levels of PGC1a. However, oxygen consumption in ESCs was only 0.75nmol oxygen/min per million cells and showed minimal increase with addition of the mitochondrial uncoupler FCCP while AoSMC consumed 4.6nmol/min at baseline and increased to 14 nmol/min with FCCP.ConclusionESCs express high levels of mitochondrial genes and contain substantial mitochondrial mass, but they show minimal evidence of mitochondrial oxygen consumption when compared to mature vascular cells. Understanding the metabolic mechanisms underlying ESC self‐renewal may permit optimization of ESC‐based regenerative therapies by modulating their metabolism.Grant Funding Source: NIH and Heart Research Foundation