A shared gene expression signature in human blastocyst embryos affected by a mitochondrial defect.

Mitochondrial DNA (mtDNA) quantitative and qualitative defects have been associated with impaired human embryonic development, but the underlying mechanisms remain unknown. By using human embryos affected by mitochondrial disorders as models of mitochondrial dysfunction, we compared gene expression between 9 mitochondrial embryos (carriers of a pathogenic variant in a mtDNA or a nuclear gene coding for a mitochondrial protein) to 33 controls. Transcriptomic analyses performed by RNA-Sequencing revealed a similar global transcriptional repression in mitochondrial embryos affecting a significant proportion of differentiation factors and nuclear genes encoding mitochondrial proteins. If oxidative phosphorylation was at the top of the most significant deregulated pathways, cell survival and autophagy were found to be significantly decreased in these embryos, questioning their viability. Differentially expressed genes identified in this study represent good predictive biomarkers of mitochondrial dysfunction and should be tested as markers of preimplantation development.