mtDNA Mutagenesis Disrupts Pluripotent Stem Cell Function by Altering Redox Signaling

• Published in: Cell reports (Cambridge) 2015-06, Vol.11 (10), p.1614-1624
• Main Authors: Hämäläinen, Riikka H., Ahlqvist, Kati J., Ellonen, Pekka, Lepistö, Maija, Logan, Angela, Otonkoski, Timo, Murphy, Michael P., Suomalainen, Anu
• Format: Article
• Language: English
• Subjects: Animals; Cell Differentiation - physiology; DNA, Mitochondrial - genetics; DNA, Mitochondrial - metabolism; Female; Male; Mice; Mutagenesis; Oxidation-Reduction; Pluripotent Stem Cells - metabolism; Pluripotent Stem Cells - physiology; Reactive Oxygen Species - metabolism; Signal Transduction
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2015.05.009

mtDNA mutagenesis in somatic stem cells leads to their dysfunction and to progeria in mouse. The mechanism was proposed to involve modification of reactive oxygen species (ROS)/redox signaling. We studied the effect of mtDNA mutagenesis on reprogramming and stemness of pluripotent stem cells (PSCs) and show that PSCs select against specific mtDNA mutations, mimicking germline and promoting mtDNA integrity despite their glycolytic metabolism. Furthermore, mtDNA mutagenesis is associated with an increase in mitochondrial H2O2, reduced PSC reprogramming efficiency, and self-renewal. Mitochondria-targeted ubiquinone, MitoQ, and N-acetyl-L-cysteine efficiently rescued these defects, indicating that both reprogramming efficiency and stemness are modified by mitochondrial ROS. The redox sensitivity, however, rendered PSCs and especially neural stem cells sensitive to MitoQ toxicity. Our results imply that stem cell compartment warrants special attention when the safety of new antioxidants is assessed and point to an essential role for mitochondrial redox signaling in maintaining normal stem cell function. [Display omitted] •mtDNA mutagenesis affects reprogramming and stemness through redox signaling•Altered redox signaling can be pharmacologically rescued by NAC or MitoQ•Stem cells are sensitive to mitochondria-targeted ubiquinone toxicity•Pluripotent stem cells show active selection against mtDNA mutations Hämäläinen et al. show that stem cell homeostasis and reprogramming efficiency are sensitive to mitochondrial mutagenesis and mitochondria-derived oxygen radicals, which decrease stemness. The stem cell sensitivity to redox signaling also makes them sensitive targets for antioxidants, which, if targeted to mitochondria, show dose-dependent benefits or toxicity.