Inhibition of Mitochondrial Complex III Blocks Neuronal Differentiation and Maintains Embryonic Stem Cell Pluripotency

The mitochondrion is emerging as a key organelle in stem cell biology, acting as a regulator of stem cell pluripotency and differentiation. In this study we sought to understand the effect of mitochondrial complex III inhibition during neuronal differentiation of mouse embryonic stem cells. When exposed to antimycin A, a specific complex III inhibitor, embryonic stem cells failed to differentiate into dopaminergic neurons, maintaining high Oct4 levels even when subjected to a specific differentiation protocol. Mitochondrial inhibition affected distinct populations of cells present in culture, inducing cell loss in differentiated cells, but not inducing apoptosis in mouse embryonic stem cells. A reduction in overall proliferation rate was observed, corresponding to a slight arrest in S phase. Moreover, antimycin A treatment induced a consistent increase in HIF-1α protein levels. The present work demonstrates that mitochondrial metabolism is critical for neuronal differentiation and emphasizes that modulation of mitochondrial functions through pharmacological approaches can be useful in the context of controlling stem cell maintenance/ differentiation.Fundação para a Ciência e a Tecnologia (FCT) Portugal for grant support (PTDC/EBB-EBI/101114/2008, PTDC/EBB-EBI/ 120634/2010 and PDTC/QUI-BIQ/120652/2010 co-funded by Compete/FEDER/National Funds; and a PhD scholarship attributed to SP (SFRH/BD/ 37933/2007). Center for Neuroscience and Cell Biology (CNC) funding is also supported by FCT (PEst-C/SAU/LA0001/2011). EA’s work was supported by the Swedish Foundation for Strategic Research (SRL Program), Swedish Research Council (DBRM), Karolinska Institutet (SFO Thematic Center in Stem Cells and Regenerative Medicine), and Hjärnfonden