Analysis of Ferrous on Ten-Eleven Translocation Activity and Epigenetic Modifications of Early Mouse Embryos by Fluorescence Microscopy

Iron deficiency and its epigenetic effects on iron homeostasis

Iron deficiency is a common micronutrient deficiency associated with metabolic changes in the levels of iron regulatory proteins, hepcidin and ferroportin. Studies have associated dysregulation of iron homeostasis to other secondary and life-threatening diseases including anaemia, neurodegeneration and metabolic diseases. Iron deficiency plays a critical role in epigenetic regulation by affecting the Fe²⁺/α-ketoglutarate-dependent demethylating enzymes, Ten Eleven Translocase 1-3 (TET 1-3) and Jumonji-C (JmjC) histone demethylase, which are involved in epigenetic erasure of the methylation marks on both DNA and histone tails, respectively. In this review, studies involving epigenetic effects of iron deficiency associated with dysregulation of TET 1-3 and JmjC histone demethylase enzyme activities on hepcidin/ferroportin axis are discussed.

The possible effect of lactoferrin on the epigenetic characteristics of early mammalian embryos exposed to bisphenol A

BACKGROUND

The main objective of this review was to state a hypothetical mechanism of the antitoxic effect of lactoferrin (Lf) on embryos exposed to bisphenol A (BPA). On this basis, it is possible to suggest Lf as a potential protective health component before conception upon toxic effects and viral infections.

METHODS

The narrative review was performed using systematic review methods to identify relevant literature. The resources required for this study were obtained by searching the electronic database PubMed (MEDLINE). Articles were searched using the keywords "BPA," "lactoferrin," "DNA-methylation," "epigenetic," "mammals," "human," and "mouse." The inclusion criteria were as follows: (a) primary or original research; (b) study of epigenetic modification; and (c) study focuses on early mammalian development.

RESULTS

Presented data demonstrate that Lf can modulate epigenetical characteristic, such as DNA methylation and reactive oxygen species (ROS), and, thereby, may serve as a potential readily available pharmaceutical product.

CONCLUSION

Suggested hypothesis is based on the important interrelated role of changes in epigenetic modifications and oxidative stress in early embryogenesis under the influence of BPA and virus infection as a cause of the development of pathologies in the adult organism.

Epigenetic Regulation in Uterine Fibroids-The Role of Ten-Eleven Translocation Enzymes and Their Potential Therapeutic Application

Uterine fibroids (UFs) are monoclonal, benign tumors that contain abnormal smooth muscle cells and the accumulation of extracellular matrix (ECM). Although benign, UFs are a major source of gynecologic and reproductive dysfunction, ranging from menorrhagia and pelvic pain to infertility, recurrent miscarriage, and preterm labor. Many risk factors are involved in the pathogenesis of UFs via genetic and epigenetic mechanisms. The latter involving DNA methylation and demethylation reactions provide specific DNA methylation patterns that regulate gene expression. Active DNA demethylation reactions mediated by ten-eleven translocation proteins (TETs) and elevated levels of 5-hydroxymethylcytosine have been suggested to be involved in UF formation. This review paper summarizes the main findings regarding the function of TET enzymes and their activity dysregulation that may trigger the development of UFs. Understanding the role that epigenetics plays in the pathogenesis of UFs may possibly lead to a new type of pharmacological fertility-sparing treatment method.

Epigenomic regulation by labile iron

Iron is an essential micronutrient metal for cellular functions but can generate highly reactive oxygen species resulting in oxidative damage. For these reasons its uptake and metabolism is highly regulated. A small but dynamic fraction of ferrous iron inside the cell, termed intracellular labile iron, is redox-reactive and ready to participate multiples reactions of intracellular enzymes. Due to its nature its determination and precise quantification has been a roadblock. However, recent progress in the development of intracellular labile iron probes are allowing the reevaluation of our current understanding and unmasking new functions. The role of intracellular labile iron in regulating the epigenome was recently discovered. This chapter examine how intracellular labile iron can modulate histone and DNA demethylation and how its pool can mediate a signaling pathway from cAMP serving as a sensor of the metabolic needs of the cells.

MgFe-LDH Nanoparticles: A Promising Leukemia Inhibitory Factor Replacement for Self-Renewal and Pluripotency Maintenance in Cultured Mouse Embryonic Stem Cells

Leukemia inhibitory factor (LIF), an indispensable bioactive protein that sustains self-renewal and pluripotency in stem cells, is vital for mouse embryonic stem cell (mESC) culture. Extensive research is conducted on reliable alternatives for LIF as its clinical application in stable culture and large-scale expansion of ESCs is limited by its instability and high cost. However, few studies have sought to replace LIF with nanoparticles to provide a xeno-free culture condition. MgAl-LDH (layered double hydroxide) nanoparticles can partially replace LIF in maintaining pluripotency of mESCs; however, the requirement and tolerance for aluminum ions in mice are far lesser than those of iron ions. Hence, MgFe-LDH nanoparticles are selected for this study. MgFe-LDH is superior to MgAl-LDH in maintaining self-renewal and pluripotency of mESCs, in the absence of LIF and mouse embryonic fibroblast. Furthermore, combined transcriptomic and proteomic analysis confirms that MgFe-LDH can activate the LIF receptor (LIFR)/phosphatidylinositol 3-kinase (PI3K)/protein kinase B(AKT), LIFR/JAK/janus kinase (JAK)/signal transducer and activator of transcription 3(STAT3), and phospho-signal transducer and activator of transcription 3(p-STAT3)/ten-eleven translocation (TET) signaling pathways, while the extra Fe2+ provided by MgFe-LDH would also enhance TET1/2 abundance thus affecting the TET1/2 regulated pluripotency related marker expression and TET1/2 meditated DNA demethylation. These results suggest that MgFe-LDH nanoparticles can thus be used as an affordable and efficient replacement for LIF in mESC cultivation.

[Progress on epigenetic regulation of iron homeostasis]

Iron homeostasis plays an important role for the maintenance of human health. It is known that iron metabolism is tightly regulated by several key genes, including divalent metal transport-1(DMT1), transferrin receptor 1(TFR1), transferrin receptor 2(TFR2), ferroportin(FPN), hepcidin(HAMP), hemojuvelin(HJV) and Ferritin H. Recently, it is reported that DNA methylation, histone acetylation, and microRNA (miRNA) epigenetically regulated iron homeostasis. Among these epigenetic regulators, DNA hypermethylation of the promoter region of FPN, TFR2, HAMP, HJV and bone morphogenetic protein 6 (BMP6) genes result in inhibitory effect on the expression of these iron-related gene. In addition, histone deacetylase (HADC) suppresses HAMP gene expression. On the contrary, HADC inhibitor upregulates HAMP gene expression. Additional reports showed that miRNA can also modulate iron absorption, transport, storage and utilization via downregulation of DMT1, FPN, TFR1, TFR2, Ferritin H and other genes. It is noteworthy that some key epigenetic regulatory enzymes, such as DNA demethylase TET2 and histone lysine demethylase JmjC KDMs, require iron for the enzymatic activities. In this review, we summarize the recent progress of DNA methylation, histone acetylation and miRNA in regulating iron metabolism and also discuss the future research directions.

Epigenetic agents in combined anticancer therapy

In the last decade, epigenetic drugs (such as inhibitors of DNA methyltransferases and histone deacetylases) have been intensively used for cancer treatment. Their applications have shown high anticancer effectivity and tolerable side effects. However, they are unfortunately not effective in the treatment of some types and phenotypes of cancers. Nevertheless, several studies have demonstrated that problems of drug efficacy can be overcome through the combined application of therapeutic modulates. Therefore, combined applications of epigenetic agents with chemotherapy, radiation therapy, immunotherapy, oncolytic virotherapy and hyperthermia have been presented. This review summarizes and discusses the general principles of this approach, as introduced and supported by numerous examples. In addition, predictions of the future potential applications of this methodology are included.

Regulation and Functional Significance of 5-Hydroxymethylcytosine in Cancer

Epigenetic modes of gene regulation are important for physiological conditions and its aberrant changes can lead to disease like cancer. 5-hydroxymethylcytosine (5hmC) is an oxidized form of 5-methylcytosine (5mC) catalyzed by Ten Eleven Translocation (TET) enzymes. 5hmC is considered to be a demethylation intermediate and is emerging as a stable and functional base modification. The global loss of 5hmC level is commonly observed in cancers and tumorigenic germline mutations in IDH, SDH and FH are found to be inhibiting TET activity. Although a global loss of 5hmC is characteristic in cancers, locus-specific 5hmC gain implicates selective gene expression control. The definitive role of 5hmC as a tumor suppressing or promoting modification can be deduced by identifying locus-specific 5hmC modification in different types of cancer. Determining the genes carrying 5hmC modifications and its selective variation will open up new therapeutic targets. This review outlines the role of global and locus-specific changes of 5hmC in cancers and the possible mechanisms underlying such changes. We have described major cellular factors that influence 5hmC levels and highlighted the significance of 5hmC in tumor micro environmental condition like hypoxia.

Ascorbic acid increases demethylation in somatic cell nuclear transfer embryos of the pig (Sus scrofa)

Objective

Investigated the effect and mechanism of ascorbic acid on the development of porcine embryos produced by somatic cell nuclear transfer (SCNT).

Methods

Porcine embryos were produced by SCNT and cultured in the presence or absence of ascorbic acid. Ten-eleven translocation 3 (TET3) in oocytes was knocked down by siRNA injection. After ascorbic acid treatment, reprogramming genes were analyzed by realtime reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, relative 5-methylcytosine and 5-hydroxymethylcytosine content in pronucleus were detected by realtime PCR.

Results

Ascorbic acid significantly increased the development of porcine embryos produced by SCNT. After SCNT, transcript levels of reprogramming genes, Pou5f1, Sox2, and Klf were significantly increased in blastocysts. Furthermore, ascorbic acid reduced 5-methylcytosine content in pronuclear embryos compared with the control group. Knock down of TET3 in porcine oocytes significantly prevents the demethylation of somatic cell nucleus after SCNT, even if in the presence of ascorbic acid.

Conclusion

Ascorbic acid enhanced the development of porcine SCNT embryos via the increased TET3 mediated demethylation of somatic nucleus.