title: Mitochondrial Spare Respiratory Capacity Is Negatively Correlated with Nuclear Reprogramming Efficiency.
abstract: Nuclear reprogramming efficiency has been shown to be highly variable among different types of somatic cells and different individuals, yet the underlying mechanism remains largely unknown. Several studies have shown that reprogramming of fibroblasts into induced pluripotent stem cells (iPSCs) requires remodeling of mitochondria and a metabolic shift from an oxidative state to a more glycolytic state. In this study, we evaluated the nuclear reprogramming efficiency in relation to mitochondrial bioenergetic parameters of fibroblasts from seven different human individuals. Using the Seahorse extracellular energy flux analyzer, we measured oxygen consumption rate (OCR) profiles of the cells, along with their nuclear reprogramming efficiency into iPSCs. Our results showed that fibroblasts with the lowest mitochondrial spare respiratory capacity (SRC) had the highest nuclear reprogramming efficiency, opposed to fibroblasts with the highest mitochondrial SRC, which showed lowest reprogramming efficiency. Furthermore, we found that targeted fluorescent tagging of endogenous genes (MYH6 and COL2A1) by CRISPR/Cas9-mediated homologous recombination was accompanied by an increase in the SRC level of the modified fibroblasts and impaired reprogramming efficiency. Our findings indicate a negative correlation between high mitochondrial SRC in somatic cells and low reprogramming efficiencies. This type of analysis potentially allows screening and predicting reprogramming efficiency before reprogramming, and further suggests that nuclear reprogramming might be improved by approaches that modulate the SRC.
authors: 1 Department of Biomedicine, Aarhus University , Aarhus C, Denmark .
authors: Yan
authors: Y
authors: Zhou
authors: 2 Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University , Aarhus N, Denmark .
authors: Rasha Abdelkadhem
authors: RA
authors: Al-Saaidi
authors: 2 Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University , Aarhus N, Denmark .
authors: Paula
authors: P
authors: Fernandez-Guerra
authors: 3 Department of Veterinary Clinical and Animal Sciences, Copenhagen University , Frederiksberg C, Denmark .
authors: Kristine K
authors: KK
authors: Freude
authors: 2 Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University , Aarhus N, Denmark .
authors: Rikke Katrine Jentoft
authors: RK
authors: Olsen
authors: 4 Department of Clinical Genetics, Aarhus University Hospital , Aarhus N, Denmark .
authors: Uffe Birk
authors: UB
authors: Jensen
authors: 2 Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University , Aarhus N, Denmark .
authors: Niels
authors: N
authors: Gregersen
authors: 3 Department of Veterinary Clinical and Animal Sciences, Copenhagen University , Frederiksberg C, Denmark .
authors: Poul
authors: P
authors: Hyttel
authors: 1 Department of Biomedicine, Aarhus University , Aarhus C, Denmark .|5 Danish Regenerative Engineering Alliance for Medicine (DREAM), Aarhus University , Aarhus C, Denmark .
authors: Lars
authors: L
authors: Bolund
authors: 1 Department of Biomedicine, Aarhus University , Aarhus C, Denmark .
authors: Lars
authors: L
authors: Aagaard
authors: 2 Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University , Aarhus N, Denmark .|5 Danish Regenerative Engineering Alliance for Medicine (DREAM), Aarhus University , Aarhus C, Denmark .
authors: Peter
authors: P
authors: Bross
authors: 1 Department of Biomedicine, Aarhus University , Aarhus C, Denmark .|5 Danish Regenerative Engineering Alliance for Medicine (DREAM), Aarhus University , Aarhus C, Denmark .
authors: Yonglun
authors: Y
authors: Luo
mesh_terms: D000293:Adolescent; D019069:Cell Respiration; D065150:Cellular Reprogramming; D002648:Child; D002675:Child, Preschool; D020405:Dermis / Q000166:cytology; D004734:Energy Metabolism; D005260:Female; D005347:Fibroblasts / Q000378:metabolism; D000072669:Gene Editing; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000378:metabolism*; D015203:Reproducibility of Results
keywords: induced pluripotent stem cells; mitochondrial spare respiratory capacity; nuclear reprogramming; oxidative phosphorylation; reprogramming efficiency