Suboptimal culture conditions induce more deviations in gene expression in male than female bovine blastocysts

Abstract

BackgroundSince the development of in vitro embryo production in cattle, different supplements have been added to culture media to support embryo development, with serum being the most popular. However, the addition of serum during embryo culture can induce high birthweights and low viability in calves (Large Offspring Syndrome). Analysis of global gene expression in bovine embryos produced under different conditions can provide valuable information to optimize culture media for in vitro embryo production.ResultsWe used RNA sequencing to examine the effect of in vitro embryo production, in either serum-containing or serum-free media, on the global gene expression pattern of individual bovine blastocysts. Compared to in vivo derived embryos, embryos produced in serum-containing medium had five times more differentially expressed genes than embryos produced in serum-free conditions (1109 vs. 207). Importantly, in vitro production in the presence of serum appeared to have a different impact on the embryos according to their sex, with male embryos having three times more genes differentially expressed than their female counterparts (1283 vs. 456). On the contrary, male and female embryos produced in serum-free conditions showed the same number (191 vs. 192) of genes expressed differentially; however, only 44 of those genes were common in both comparisons. The pathways affected by in vitro production differed depending on the type of supplementation. For example, embryos produced in serum-containing conditions had a lower expression of genes related to metabolism while embryos produced in serum-free conditions showed aberrations in genes involved in lipid metabolism.ConclusionsSerum supplementation had a major impact on the gene expression pattern of embryos, with male embryos being the most affected. The transcriptome of embryos produced in serum-free conditions showed a greater resemblance to that of in vivo derived embryos, although genes involved in lipid metabolism were altered. Male embryos appeared to be most affected by suboptimal in vitro culture, i.e. in the presence of serum.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2393-z) contains supplementary material, which is available to authorized users.

Long term effects of ART: What do animals tell us?

“…Whatever the reason for this lack of data, sex dimorphisms very likely exist in human embryo since it has been evidenced in bovine embryo facing different culture conditions. Its extend varies with culture conditions, with male blastocysts having three times more deregulated genes than female ones in suboptimal conditions (Heras et al, ) and bovine female blastocysts being more prone to apoptosis (Ghys et al, ; Tan, Wang, Zhang, An, & Tian, ). Interestingly, an higher sensitivity of female blastocysts to IVF resulting in increased apopotosis has also been reported in mouse (Tan, Zhang, et al, ).…”

“…In cattle, three recent studies used RNA seq to compare the transcriptome of blastocysts produced from in vitro matured oocytes recovered from slaughtered cows, that were in vitro fertilized and in vitro cultured in serum free conditions (CR1 medium (Gad et al, ) or SOF medium (Driver et al, ; Heras et al, )) to blastocysts developed in vivo from superovulated and artificially inseminated cows. They evidenced several hundred differentially expressed genes (DEG) respectively.…”

Sexual Dimorphism of miRNAs Secreted by Bovine In vitro-produced Embryos

“…Further, when exposed to adverse culture conditions, male and female conceptuses exhibit differentially altered transcriptomes (Heras et al, 2016). Additionally, mitochondrial distribution, telomere length, and DNA methylation have shown sexual dimorphism in bovine embryos (Bermejo-Álvarez et al, 2008).…”

The embryonic stress response to in vitro culture: insight from genomic analysis

“…Data from mouse (Heras et al 2016) and human (Highet et al 2015, Kleijkers et al 2015 studies using different transcriptomic platforms are also provided. The transcriptomic biomarkers associated with compromised preimplantation development after IVC are involved in important biological functions such as metabolic homeostasis, extracellular matrix remodelling, inflammation and signal transduction.…”