Hyaluronic acid and epidermal growth factor improved the bovine embryo quality by regulating the DNA methylation and expression patterns of the focal adhesion pathway

Abstract

Focal adhesion pathway is one of the key molecular pathways affected by suboptimal culture conditions during embryonic development. The epidermal growth factor (EGF) and hyaluronic acid (HA) are believed to be involved in the focal adhesion pathway function by regulating the adherence of the molecules to the extracellular matrix. However, regulatory and molecular mechanisms through which the EGF and HA could influence the embryo development is not clear. Therefore, this study aimed to investigate the effect of continued or stage specific supplementation of EGF and/or HA on the developmental competence and quality of bovine preimplantation embryos and the subsequent consequences on the expression and DNA methylation patterns of genes involved in the focal adhesion pathway. The results revealed that, the supplementation of EGF or HA from zygote to the blastocysts stage reduced the level of reactive oxygen species and increased hatching rate after thawing. On the other hand, HA decreased the apoptotic nuclei and increased blastocyst compared to EGF supplemented group. Gene expression and DNA methylation analysis in the resulting blastocysts indicated that, combined supplementation of EGF and HA increased the expression of genes involved in focal adhesion pathway while supplementation of EGF, HA or a combination of EGF and HA during the entire preimplantation period changed the DNA methylation patterns of genes involved in focal adhesion pathway. On the other hand, blastocysts developed in culture media supplemented with EGF + HA until the 16-cell stage exhibited higher expression level of genes involved in focal adhesion pathway compared to those supplemented after the 16-cell stage. Conversely, the DNA methylation level of candidate genes was increased in the blastocysts obtained from embryos cultured in media supplemented with EGF + HA after 16-cell stage. In conclusion, supplementation of bovine embryos with EGF and/or HA during the entire preimplantation period or in a stage specific manner altered the DNA methylation and expression patterns of candidate genes involved in the focal adhesion pathway which was in turn associated with the observed embryonic developmental competence and quality.

Simple and Efficient Chemically Defined In Vitro Maturation and Embryo Culture System for Bovine Embryos

“…In bovines, the addition of IGF1 increased the morula/blastocyst yield [ 43 , 60 , 61 ], showed a thermoprotective effect against thermal shock [ 62 ], and accelerated the rate of development in vitro [ 63 ]. Saeed-Zidane et al (2019) have indicated that the higher competence and quality of bovine embryos cultured with EGF is associated with changes on DNA methylation and expression of genes involved in the focal adhesion pathway [ 64 ].…”

Application of multi-omics data integration and machine learning approaches to identify epigenetic and transcriptomic differences between in vitro and in vivo produced bovine embryos

“…Interestingly, previous work reported that culture conditions of IVP embryos de-regulated the focal adhesion pathway at the blastocyst stage [ 61 ]. Furthermore, supplementation of the culture media with epidermal growth factor (EGF) and hyaluronic acid (HA) during or after embryonic genome activation altered the expression and DNA methylation patterns of genes involved in this pathway [ 62 ]. Stimulation of growth factors, such as EGF, and adhesion to the ECM is required for normal cell growth [ 63 ], and HA is one of the main components of ECM, that can improve the blastocyst rate of IVP bovine embryos [ 64 ].…”

Exploring the Role of Hyaluronic Acid in Reproductive Biology and Beyond: Applications in Assisted Reproduction and Tissue Engineering

“…This efficiency may be linked to the age of the embryo because when blastocysts are cultured with epidermal growth factor (EGF) + HA until the 16‐cell stage, an increase in the expression of genes associated with the focal adhesion pathway was observed as compared to supplementation after the 16‐cell stage. [ 135 ] A similar method has proven successful in improving IVP in pigs. The study found that adding 1 mg mL −1 , HA increased the percentage of cleaved embryos to ≈95%, morulae to ≈87%, and blastocysts to ≈77%.…”