Cells Survive Without Mitochondria — Revealing Hidden Rules of Pluripotency

Mitochondria are essential organelles that power cells and carry their own genome (mtDNA), yet methods to precisely manipulate mitochondrial abundance for functional studies have remained limited. This landmark study from Jun Wu's lab at UT Southwestern Medical Center introduces an enforced mitophagy system capable of selectively eliminating mitochondria from living cells and embryos, providing an unprecedented tool to study mitochondrial contributions to pluripotency and development.

The team first demonstrated that pluripotent stem cells (PSCs) could survive for several days in culture after complete mitochondrial elimination — a surprising finding that challenges assumptions about the absolute necessity of mitochondria for short-term cellular viability. This temporal window was then exploited to generate interspecies PSC fusions that harbor either human or non-human hominid (NHH) mitochondrial DNA within a defined nuclear background, enabling controlled comparison of mtDNA species effects.

Comparative analyses of these hybrid lines using RNA sequencing, proteomics, and metabolomics showed that human and NHH mtDNA are largely functionally interchangeable in supporting pluripotency. However, nuclear-mitochondrial DNA divergence between species produced subtle but reproducible species-specific differences in transcription and cellular metabolism, suggesting that co-evolution of nuclear and mitochondrial genomes influences cell biology even when core pluripotency is maintained.

Extending the system to mouse embryos, the researchers developed a transgenic enforced mitophagy approach and showed that reducing mitochondrial abundance caused delayed development at the pre-implantation stage. This in vivo application validates the model's utility beyond cell culture and points to mitochondrial abundance as a rate-limiting factor for early embryogenesis.

The study opens multiple research avenues: understanding mitochondrial disease mechanisms, probing how nuclear-mitochondrial coevolution shapes species-specific biology, and potentially enabling new strategies for mitochondrial replacement therapies. A patent application has been filed on the enforced mitophagy platform, underscoring its translational potential.