DNA methylation, environmental exposures and early embryo development

Abstract

The first crucial step in the developmental program occurs during pre-implantation, the time after the oocyte has been fertilized and before the embryo implants in the uterus. This period represents a vulnerable window as the epigenome undergoes dynamic changes in DNA methylation profiles. Alterations in the early embryonic reprogramming wave can impair DNA methylation patterns and induce permanent changes to the developmental program, leading to the onset of adverse health outcomes in offspring. Although there is an increasing body of evidence indicating that harmful exposures during preimplantation embryo development can trigger lasting epigenetic alterations in offspring, the mechanisms are still not fully understood. Since physiological or pathological changes in DNA methylation can occur as a response to environmental cues, proper environmental milieu plays a critical role in the success of embryonic development. In this review, we depict the mechanisms behind the embryonic epigenetic reprogramming of DNA methylation and highlight how maternal environmental stressors (e.g., alcohol, heat stress, nutrient availability) during pre-implantation and assisted reproductive technology procedures affect development and DNA methylation marks.

Effect of prenatal ambient temperature on the performance physiological parameters, and oxidative metabolism of Japanese quail (Coturnix coturnix japonica) layers exposed to heat stress during growth

“…As described above, early-life stress can be associated with both costs and benefits 12 . Adverse conditions experienced by the maternal generation have been shown to influence the susceptibility of offspring to challenges and diseases 38 , 39 . According to Dixon et al 15 , the prenatal environment may influence offspring development.…”

Relationships among Inorganic Arsenic, Nutritional Status CpG Methylation and microRNAs: A Review of the Literature

“…Alterations in the early embryonic reprogramming can lead to changes in DNA methylation patterns, inducing permanent impairments to the developmental program which may result in adverse health outcome. 43 Changes in DNA methylation can occur as a result of maternal environmental exposure influencing embryonic development as well as lasting epigenetic alterations in offspring. 43 In relation to iAs exposure, researchers have identified a suite of genes with altered methylation status in association with arsenicosis.…”

“…43 Changes in DNA methylation can occur as a result of maternal environmental exposure influencing embryonic development as well as lasting epigenetic alterations in offspring. 43 In relation to iAs exposure, researchers have identified a suite of genes with altered methylation status in association with arsenicosis. 44 The identified genes encode proteins that are involved in cancer, diabetes, and heart disease including SWI/ SNF related, matrix associated, actin-dependent regulator of chromatin, subfamily d, member 2 (SMARCD2), homeobox B9 (HOXB9); msh homeobox 1, also known as HOX7 (MSX1) and matrix metallopeptidase 15 (membrane inserted; MMP15).…”

Epigenetic Changes in Equine Embryos After Short-term Storage at Different Temperatures

“…During early embryonic development, an increased expression of growth factors leads to proliferation and prostaglandin production by trophectoderm cells, likely involved in maternal recognition of pregnancy [15]. At the same time, DNA methyltransferases (DNMTs) play an important role in maintaining genome stability and integrity during development and epigenetic reprogramming [16] with DNMT1, DNMT3A, DNMT3B, and DNMT3L being the main genes involved in the establishment of methylation patterns required for cell lineage determination [17][18][19]. There is evidence that DNA methylation occurs mainly at the cytosines of cytosine-guanine dinucleotides (CpG) known as CpG sites [16].…”

“…At the same time, DNA methyltransferases (DNMTs) play an important role in maintaining genome stability and integrity during development and epigenetic reprogramming [16] with DNMT1, DNMT3A, DNMT3B, and DNMT3L being the main genes involved in the establishment of methylation patterns required for cell lineage determination [17][18][19]. There is evidence that DNA methylation occurs mainly at the cytosines of cytosine-guanine dinucleotides (CpG) known as CpG sites [16]. Interactions between DNA and gene regulatory proteins can be critically in uenced by the dynamics of DNA methylation.…”