Functional variability among human clones of induced pluripotent stem cells (hiPSCs) remains a limitation in assembling high‐quality biorepositories. Beyond inter‐person variability, the root cause of intra‐person variability remains unknown. Mitochondria guide the required transition from oxidative to glycolytic metabolism in nuclear reprogramming. Moreover, mitochondria have their own genome (mitochondrial DNA [mtDNA]). Herein, we performed mtDNA next‐generation sequencing (NGS) on 84 hiPSC clones derived from a cohort of 19 individuals, including mitochondrial and non‐mitochondrial patients. The analysis of mtDNA variants showed that low levels of potentially pathogenic mutations in the original fibroblasts are revealed through nuclear reprogramming, generating mutant hiPSCs with a detrimental effect in their differentiated progeny. Specifically, hiPSC‐derived cardiomyocytes with expanded mtDNA mutations non‐related with any described human disease, showed impaired mitochondrial respiration, being a potential cause of intra‐person hiPSC variability. We propose mtDNA NGS as a new selection criterion to ensure hiPSC quality for drug discovery and regenerative medicine.
Low level of natural heteroplasmy in mitochondrial DNA in parental fibroblasts can be revealed during nuclear reprogramming in both healthy and diseased individuals and is a potential source of intra‐person hiPSC variability.
Low levels of heteroplasmic mitochondrial DNA (mtDNA) Global Private Mutations (GPMs) from the original fibroblasts are revealed in hiPSC clones during nuclear reprogramming.
hiPSC‐derived cardiomyocytes with GPMs show reduced mitochondrial oxygen consumption compared with isogenic wild‐type controls.
Universal heteroplasmy is a potential source of intra‐person hiPSC variability.
mtDNA next‐generation sequencing is a new hiPSCs selection criterion with the capacity to identify hiPSC clones representative of the patient for further applications.
- Received May 27, 2016.
- Revision received June 23, 2016.
- Accepted June 24, 2016.
- © 2016 The Authors