Mammalian fertilization begins with the fusion of two specialized gametes, followed by major epigenetic remodeling leading to the formation of a totipotent embryo. During the development of the pre-implantation embryo, precise reprogramming progress is a prerequisite for avoiding developmental defects or embryonic lethality, but the underlying molecular mechanisms remain elusive. For the past few years, unprecedented breakthroughs have been made in mapping the regulatory network of dynamic epigenomes during mammalian early embryo development, taking advantage of multiple advances and innovations in low-input genome-wide chromatin analysis technologies. The aim of this review is to highlight the most recent progress in understanding the mechanisms of epigenetic remodeling during early embryogenesis in mammals, including DNA methylation, histone modifications, chromatin accessibility and 3D chromatin organization.
Animals ; Chromatin Assembly and Disassembly ; DNA Methylation ; DNA Transposable Elements ; Embryo, Mammalian ; Embryonic Development/genetics* ; Epigenesis, Genetic ; Epigenome ; Female ; Fertilization/physiology* ; Gene Expression Regulation, Developmental ; Histone Code ; Histones/metabolism* ; Male ; Mice ; Oocytes/metabolism* ; Spermatozoa/metabolism*

OBJECTIVEThe aim of this study was to investigate the ability of Pref-1+ adipocyte progenitor cells to mobilize into mesenteric lymph nodes (MLNs) and the dynamic expression of related chemokines during the development of rat MLNs.

METHODSImmunohistochemical analyses were used to detect the expression of Pref-1 and related chemokines. Transmission electron microscopy (TEM) was used to observe the changes in ultrastructure of MLNs.

RESULTSCells containing lipid droplets were found in all rat MLNs at embryonic day (E) 18.5, 2 and 6 weeks (w) after birth, and they were similar to fibroblastic reticular cells (FRCs) or follicular dendritic cells (FDCs) under TEM. Pref-1+ adipocyte progenitor cells were found in all MLNs. The expression level of Pref-1 was significantly increased at 2 w after birth and decreased at 6 w after birth. The tendency of Cxcl12 expression was consistent with that of Pref-1 and was positively correlated with the expression of Pref-1 (P < 0.01; r = 0.897). At E18.5, Cxcl13, and Ccr7 were significantly expressed in the MLN anlage, but the expression level of Ccl21 was low. The expression level of Cxcl13, Ccr7, and Ccl21 in MLN were significantly increased at 2 w after birth (P < 0.05), while the expression of Ccr7 and Ccl21 were significantly decreased at 6 w after birth (P < 0.05).

CONCLUSIONAdipocyte progenitor cells are involved in the rat MLNs development through differentiation into FRC and FDC. The expression of the relevant chemokines during the development of MLNs is dynamic and may be related to the maintenance of lymph nodes self-balance state.

Animals ; Chemokines ; genetics ; metabolism ; Female ; Gene Expression Regulation, Developmental ; physiology ; Intercellular Signaling Peptides and Proteins ; genetics ; metabolism ; Lymph Nodes ; embryology ; metabolism ; Membrane Proteins ; genetics ; metabolism ; Mesentery ; embryology ; Pregnancy ; Rats

Oligodendrocytes (OLs) are myelinating glial cells that form myelin sheaths around axons to ensure rapid and focal conduction of action potentials. Here, we found that an axonal outgrowth regulatory molecule, AATYK (apoptosis-associated tyrosine kinase), was up-regulated with OL differentiation and remyelination. We therefore studied its role in OL differentiation. The results showed that AATYK knockdown inhibited OL differentiation and the expression of myelin genes in vitro. Moreover, AATYK-deficiency maintained the proliferation status of OLs but did not affect their survival. Thus, AATYK is essential for the differentiation of OLs.
Animals ; Animals, Newborn ; Apoptosis Regulatory Proteins ; genetics ; metabolism ; Cell Differentiation ; drug effects ; physiology ; Cell Proliferation ; drug effects ; genetics ; Cells, Cultured ; Cuprizone ; toxicity ; Demyelinating Diseases ; chemically induced ; metabolism ; pathology ; Embryo, Mammalian ; Gene Expression Regulation, Developmental ; genetics ; Ki-67 Antigen ; metabolism ; Mice ; Mice, Inbred C57BL ; Myelin Basic Protein ; metabolism ; Myelin Proteolipid Protein ; metabolism ; Myelin Sheath ; drug effects ; metabolism ; Oligodendroglia ; drug effects ; metabolism ; Protein-Tyrosine Kinases ; genetics ; metabolism ; RNA, Small Interfering ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley

The study illustrate the inner correlation between global DNA methylation variation and different birth weights. Infant birth weight was used to identify cases and controls. Cord blood and placentas were collected. We performed DNA methylation profiling of bisulphite-converted DNA. We have identified many differentially methylated CpG sites in experimental groups; these sites involved in hundreds of signalings. Among these, more than ten pathways were referred to the glucose and lipid metabolism. Methylation changes in the insulin-signaling pathway (ISP), adipocytokine signaling pathway (ASP) and MAPK signaling pathway are involved in the fetal programming of diabetes..
Birth Weight ; DNA Methylation ; Female ; Gene Expression Regulation, Developmental ; physiology ; Genome-Wide Association Study ; Humans ; Infant, Newborn ; Male ; Organ Size ; Placenta ; anatomy & histology ; Pregnancy ; Signal Transduction

OBJECTIVEThis study aimed to investigate the expression pattern and function of Nuclear receptor subfamily 2 group E member 1 (Nr2e1) in retinoic acid (RA)-induced brain abnormality.

METHODSThe mouse model of brain abnormality was established by administering 28 mg/kg RA, and neural stem cells (NSCs) were isolated from the mouse embryo and cultured in vitro. Nr2e1 expression was detected by whole mount in situ hybridization, RT-PCR, and Western blotting. Nr2e1 function was determined by transducing Nr2e1 shRNA into NSCs, and the effect on the sonic hedgehog (Shh) signaling pathway was assessed in the cells. In addition, the regulation of Nr2e1 expression by RA was also determined in vitro.

RESULTSNr2e1 expression was significantly downregulated in the brain and NSCs of RA-treated mouse embryos, and knockdown of Nr2e1 affected the proliferation of NSCs in vitro. In addition, a similar expression pattern of Nr2e1 and RA receptor (RAR) α was observed after treatment of NSCs with different concentrations of RA.

CONCLUSIONOur study demonstrated that Nr2e1 could be regulated by RA, which would aid a better understanding of the mechanism underlying RA-induced brain abnormality.

Animals ; Brain ; cytology ; embryology ; Cell Proliferation ; Down-Regulation ; Gene Expression Regulation ; Gene Expression Regulation, Developmental ; drug effects ; Mice ; Mice, Inbred C57BL ; Neural Stem Cells ; drug effects ; physiology ; Receptors, Cytoplasmic and Nuclear ; genetics ; metabolism ; Tretinoin ; pharmacology

Coordination of cell division and cell fate is crucial for the successful development of mammalian early embryos. Aurora kinases are evolutionarily conserved serine/threonine kinases and key regulators of mitosis. Aurora kinase B (AurkB) is ubiquitously expressed while Aurora kinase C (AurkC) is specifically expressed in gametes and preimplantation embryos. We found that increasing AurkC level in one blastomere of the 2-cell embryo accelerated cell division and decreasing AurkC level slowed down mitosis. Changing AurkB level had the opposite effect. The kinase domains of AurkB and AurkC were responsible for their different ability to phosphorylate Histone H3 Serine 10 (H3S10P) and regulate metaphase timing. Using an Oct4-photoactivatable GFP fusion protein (Oct4-paGFP) and fluorescence decay after photoactivation assay, we found that AurkB overexpression reduced Oct4 retention in the nucleus. Finally, we show that blastomeres with higher AurkC level elevated pluripotency gene expression, which were inclined to enter the inner cell mass lineage and subsequently contributed to the embryo proper. Collectively, our results are the first demonstration that the activity of mitotic kinases can influence cell fate decisions in mammalian preimplantation embryos and have important implications to assisted reproduction.
Animals ; Aurora Kinase B ; metabolism ; Aurora Kinase C ; metabolism ; Blastocyst ; metabolism ; Gene Expression Regulation, Developmental ; physiology ; Histones ; metabolism ; Mice ; Phosphorylation ; physiology

Histone methylation is one of the most widely studied post-transcriptional modifications. It is thought to be an important epigenetic event that is closely associated with cell fate determination and differentiation. To explore the spatiotemporal expression of histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 27 trimethylation (H3K27me3) epigenetic marks and methylation or demethylation transferases in tooth organ development, we measured the expression of SET7, EZH2, KDM5B and JMJD3 via immunohistochemistry and quantitative polymerase chain reaction (qPCR) analysis in the first molar of BALB/c mice embryos at E13.5, E15.5, E17.5, P0 and P3, respectively. We also measured the expression of H3K4me3 and H3K27me3 with immunofluorescence staining. During murine tooth germ development, methylation or demethylation transferases were expressed in a spatial-temporal manner. The bivalent modification characterized by H3K4me3 and H3K27me3 can be found during the tooth germ development, as shown by immunofluorescence. The expression of SET7, EZH2 as methylation transferases and KDM5B and JMJD3 as demethylation transferases indicated accordingly with the expression of H3K4me3 and H3K27me3 respectively to some extent. The bivalent histone may play a critical role in tooth organ development via the regulation of cell differentiation.
Animals ; Cell Differentiation ; physiology ; DNA-Binding Proteins ; analysis ; Dental Papilla ; embryology ; Embryo, Mammalian ; Enamel Organ ; embryology ; Enhancer of Zeste Homolog 2 Protein ; Epigenesis, Genetic ; physiology ; Gene Expression Regulation, Developmental ; Histone-Lysine N-Methyltransferase ; analysis ; Histones ; metabolism ; Jumonji Domain-Containing Histone Demethylases ; analysis ; Lysine ; metabolism ; Methylation ; Mice ; Mice, Inbred BALB C ; Odontogenesis ; physiology ; Polycomb Repressive Complex 2 ; analysis ; Protein Processing, Post-Translational ; physiology ; Tooth Germ ; embryology

Oval cells have a potential to differentiate into a variety of cell lineages including hepatocytes and biliary epithelia. Several models have been established to activate the oval cells by incorporating a variety of toxins and carcinogens, alone or combined with surgical treatment. Those models are obviously not suitable for the study on human hepatic oval cells. It is necessary to establish a new and efficient model to study the human hepatic oval cells. In this study, the hepatocyte growth factor (HGF) and epidermal growth factor (EGF) were used to induce differentiation of mouse embryonic stem (ES) cells into hepatic oval cells. We first confirmed that hepatic oval cells derived from ES cells, which are bipotential, do exist during the course of mouse ES cells' differentiation into hepatic parenchymal cells. RT-PCR and transmission electron microscopy were applied in this study. The ratio of Sca-1+/CD34+ cells sorted by FACS in the induction group was increased from day 4 and reached the maximum on the day 8, whereas that in the control group remained at a low level. The differentiation ratio of Sca-1+/CD34+ cells in the induction group was significantly higher than that in the control group. About 92.48% of the sorted Sca-1+/CD34+ cells on the day 8 were A6 positive. Highly purified A6+/Sca-1+/CD34+ hepatic oval cells derived from ES cells could be obtained by FACS. The differentiation ratio of hepatic oval cells in the induction group (up to 4.46%) was significantly higher than that in the control group. The number of hepatic oval cells could be increased significantly by HGF and EGF. The study also examined the ultrastructures of ES-derived hepatic oval cells' membrane surface by atomic force microscopy. The ES-derived hepatic oval cells cultured and sorted by our protocols may be available for the future clinical application.
Animals ; Antigens, CD34 ; genetics ; metabolism ; Antigens, Ly ; genetics ; metabolism ; Cell Differentiation ; drug effects ; genetics ; physiology ; Cell Line ; Embryonic Stem Cells ; cytology ; metabolism ; ultrastructure ; Epidermal Growth Factor ; pharmacology ; Flow Cytometry ; Gene Expression Regulation, Developmental ; drug effects ; Hepatocyte Growth Factor ; pharmacology ; Liver ; cytology ; metabolism ; Membrane Proteins ; genetics ; metabolism ; Mice ; Mice, Inbred BALB C ; Microfilament Proteins ; metabolism ; Microscopy, Atomic Force ; Microscopy, Electron, Transmission ; Reverse Transcriptase Polymerase Chain Reaction ; Stem Cells ; cytology ; metabolism ; ultrastructure ; Time Factors

Non-coding RNA is a kind of non-coding protein RNA which is widely present in most of the organisms. Non-coding RNA plays key roles in the embryonic development,cell fate determination,and growth control in the living organisms. MicroRNA and long non-coding RNA involve in differentiation of endocrine cell,insulin gene expression and secretion,and insulin resistance,which are closely associated with diabetes.
Cell Differentiation ; Diabetes Mellitus ; Gene Expression ; physiology ; Gene Expression Profiling ; Gene Expression Regulation, Developmental ; Humans ; Insulin ; Insulin-Secreting Cells ; Islets of Langerhans ; growth & development ; metabolism ; MicroRNAs ; RNA, Untranslated ; metabolism

OBJECTIVETo observe the temporal modification of transcription factor Mef2c by histone acetylases (HATs) P300, PCAF, and SRC1 during cardiogenesis and to provide a basis for investigating the pathogenesis of congenital heart disease.

METHODSThe normal heart tissues from embryonic mice (embryonic days 14.5 and 16.5) and neonatal mice (postnatal days 0.5 and 7) were collected. The binding of P300, PCAF, and SRC1 to Mef2c gene and level of histone H3 acetylation in the promoter region of Mef2c were evaluated by chromatin immunoprecipitation assays. Meanwhile, real-time PCR was used to measure the mRNA expression of Mef2c.

RESULTSP300, PCAF, SRC1 were involved in histone acetylation in the promoter region of Mef2c during cardiogenesis in mice, and binding of P300, PCAF, and SRC1 to the promoter of Mef2c varied significantly in different stages of cardiogenesis (P<0.01). The level of histone H3 acetylation and mRNA expression of Mef2c in the promoter region of Mef2c also varied significantly in different stages of cardiac development (P<0.01). The levels of acetylated H3, Mef2c mRNA, and HATs (P300, PCAF, SRC1) changed over time. They were highest on embryonic day 14.5 (P<0.01), decreased gradually with cardiac development, and were maintained at low levels after birth.

CONCLUSIONSThe mRNA expression of Mef2c varies during cardiogenesis in mice, which indicates that Mef2c plays an important role in the process of cardiac development. Meanwhile, histone acetylation in the promoter region of Mef2c is regulated temporally by HATs P300, PCAF, and SRC1.

Animals ; Female ; Gene Expression Regulation, Developmental ; Heart ; embryology ; Histone Acetyltransferases ; physiology ; MEF2 Transcription Factors ; genetics ; physiology ; Male ; Mice ; Promoter Regions, Genetic ; RNA, Messenger ; analysis