Does supplementation of oocytes with additional mtDNA influence developmental outcome?

Mitochondrial DNA Supplementation of Oocytes Has Downstream Effects on the Transcriptional Profiles of Sus scrofa Adult Tissues with High mtDNA Copy Number

“…Both in vitro fertilisation and ICSI have been reported to affect imprinting, DNA methylation and gene expression compared to the children born from natural conception [30][31][32][33]. We have shown in pigs derived from mtDNA supplementation that imprint control regions of imprinted genes showed no difference in DNA methylation patterns from naturally conceived control pigs [29]. However, it is still largely unknown if: (1) altered gene expression identified during early development following mtDNA supplementation persists and affects gene expression in adult tissues; (2) supplementation through third-party (heterologous) and autologous mtDNA differently affect gene expression; and (3) imprinted genes are expressed differently in adult tissues.…”

“…In all, we collected tissue samples from three heterologous (Pigs 3.1, 3.2 and 3.3) and three autologous mtDNA-supplemented-derived pigs (pigs 12.4, 17.2 and 3.4) and three control pigs (C4, 7 and 26). Pig 3.4 was initially thought to be heterologous (Figure 1), however, mtDNA genotyping indicated that the mtDNA supplement originated from oocytes possessing identical mtDNA genotypes to the donor oocyte [29]. Therefore, we included pig 3.4 as an autologous mtDNA-supplementedderived pig for transcriptome comparisons.…”

“…Principal component analysis (PCA) showed distinct RNAseq profiles for each tissue type (Figure 2A) with high correlations between individual samples of the same tissues (R > 0.95). We have previously analysed heart RNAseq data from these pigs but only in the context of mtDNA supplementation and controls [29]. Here, we have not only compared the additional mtDNA-supplemented tissues to controls but have also compared heterologous and autologous samples to determine whether the source of mtDNA for supplementation would impact on tissue-specific gene expression (Figure 1).…”

“…For heterologous supplementation, the MT isolate was derived from third-party pig oocytes. Three sets of mtDNA-supplemented founder offspring were generated [29] as illustrated. Underlined pig IDs represent female offspring.…”

“…More recently, we have reported on the generation of pigs produced through mtDNA supplementation in combination with ICSI where the mtDNA was derived from either sister (autologous) or third-party (heterologous) oocytes [29]. Despite changes in epigenetic marks and gene expression at the blastocyst stage of development (the final stage of preimplantation development) [20,27,28], pigs derived from mtDNA supplementation revealed only minor differences in growth, and their health and well-being did not seem to be affected [29]. Both in vitro fertilisation and ICSI have been reported to affect imprinting, DNA methylation and gene expression compared to the children born from natural conception [30][31][32][33].…”