Lysine Deprivation during Maternal Consumption of Low-Protein Diets Could Adversely Affect Early Embryo Development and Health in Adulthood

The conversion of lysine to glutamate is needed for signaling in all plants and animals. In mouse embryonic stem (mES) cells, and probably their progenitors, endogenous glutamate production and signaling help maintain cellular pluripotency and proliferation, although the source of glutamate is yet to be determined. If the source of glutamate is lysine, then lysine deprivation caused by maternal low-protein diets could alter early embryo development and, consequently, the health of the offspring in adulthood. For these reasons, we measured three pertinent variables in human embryonic stem (hES) cells as a model for the inner cell masses of human blastocysts. We found that RNA encoding the alpha-aminoadipic semialdehyde synthase enzyme, which regulates glutamate production from lysine, was highly expressed in hES cells. Moreover, the mean amount of lysine consumed by hES cells was 50% greater than the mean amount of glutamate they produced, indicating that lysine is likely converted to glutamate in these cells. Finally, hES cells expressed RNA encoding at least two glutamate receptors. Since this may also be the case for hES progenitor cells in blastocysts, further studies are warranted to verify the presence of this signaling process in hES cells and to determine whether lysine deprivation alters early mammalian embryo development.

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45 Expression patterns of PRDM family genes in porcine pre-implantation embryos

Reproduction Fertility and Development ◽

10.1071/rdv32n2ab45 ◽

2020 ◽

Vol 32 (2) ◽

pp. 148

Author(s):

K. Farrell ◽

K. Uh ◽

K. Lee

Keyword(s):

Embryo Development ◽

Internal Control ◽

Target Genes ◽

Expression Patterns ◽

Embryonic Stem ◽

Germinal Vesicle ◽

Early Embryo ◽

Cell Stage ◽

Early Embryo Development

Establishing proper levels of pluripotency is essential for normal development. The genome of gametes is remodelled upon fertilisation and pluripotency-related genes are expressed in blastocysts. Multiple pluripotency-related genes are involved in the well-orchestrated process; however, detailed mechanistic actions remain elusive. The PRDM family genes are reported to be closely related to the pluripotency. A previous report noted that PRDM14 plays an important role in the maintenance of pluripotency in human embryonic stem cells (ESCs) and potentially murine ESCs; loss of PRDM14 was found to cause abnormalities in genome-wide epigenetic status. Similarly, PRDM15 was found to be a key regulator of pluripotency in mouse ESCs. Structural similarities among the PRDM family suggest that other PRDM family genes may help to establish and maintain pluripotency in embryos. Unfortunately, little is known about the expression profile of PRDM family in porcine embryos. To expand our understanding of the role of PRDM family in porcine embryos, expression patterns of PRDM gene family were investigated using reverse transcription quantitative (RTq)-PCR. Candidate PRDM family genes were selected based on previous RNA-Seq data in porcine oocytes/embryos. To conduct this study, germinal vesicle (GV), MII, zygote, 4-cell, and blastocyst samples were collected. Complementary DNA synthesised from the samples was used for RT-qPCR to analyse the expression pattern of selected PRDM family genes: PRDM2, PRDM4, PRDM6, PRDM14, and PRDM15. The expression of target genes was normalized to the YWHAG level, an internal control. Then, GV stage was used as a control for ΔΔCT analysis. Two technical replications and three biological replications were performed. Analysis of variance was used for statistical analysis and P-values<0.05 were considered significant. There was a significant decrease in PRDM2 expression in 4-cell and blastocyst, PRDM4 expression in 4-cell, and PRDM6 in all stages (MII, zygote, 4-cell, and blastocyst), compared with the GV stage. Because zygotic genome activation occurs at the 4-cell stage in the pig, the significant decrease in gene expression (PRDM2, PRDM4, and PRDM6) indicates they may be maternally originated and involved in the reprogramming process following fertilisation. On the other hand, there was a significant increase in PRDM15 expression in blastocysts and the PRDM14 transcript was only detected in blastocysts in all three biological replicates, suggesting that the genes are most likely involved in pluripotency maintenance, as was found in previous human studies. These results indicate that PRDM family genes are differentially expressed during early embryo development in pigs and may play a role in maintenance of pluripotency. For further study, we intend to evaluate the role of PRDM family genes during early embryo development in pigs.

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microRNA regulation of pluripotent state transition

Essays in Biochemistry ◽

10.1042/ebc20200028 ◽

2020 ◽

Vol 64 (6) ◽

pp. 947-954 ◽

Cited By ~ 1

Author(s):

Shao-Hua Wang ◽

Chao Zhang ◽

Yangming Wang

Keyword(s):

Stem Cells ◽

Cell Fate ◽

Embryo Development ◽

State Transition ◽

Embryonic Stem ◽

Short Review ◽

Early Embryo ◽

Mammalian Development ◽

Early Embryo Development ◽

Pluripotent State

Abstract microRNAs (miRNAs) play essential roles in mouse embryonic stem cells (ESCs) and early embryo development. The exact mechanism by which miRNAs regulate cell fate transition during embryo development is still not clear. Recent studies have identified and captured various pluripotent stem cells (PSCs) that share similar characteristics with cells from different stages of pre- and post-implantation embryos. These PSCs provide valuable models to understand miRNA functions in early mammalian development. In this short review, we will summarize recent work towards understanding the function and mechanism of miRNAs in regulating the transition or conversion between different pluripotent states. In addition, we will highlight unresolved questions and key future directions related to miRNAs in pluripotent state transition. Studies in these areas will further our understanding of miRNA functions in early embryo development, and may lead to practical means to control human PSCs for clinical applications in regenerative medicine.

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97 Function of species-specific OCT4 reporter system during porcine embryo development

Reproduction Fertility and Development ◽

10.1071/rdv33n2ab97 ◽

2021 ◽

Vol 33 (2) ◽

pp. 156

Author(s):

S.-H. Kim ◽

M. Lee ◽

K.-H. Choi ◽

D.-K. Lee ◽

J.-N. Oh ◽

...

Keyword(s):

Stem Cells ◽

Embryo Development ◽

Core Promoter ◽

Embryonic Stem ◽

Development Stage ◽

Early Embryo ◽

Distal Enhancer ◽

Reporter System ◽

Early Embryo Development ◽

Species Specific

The present study examined the activity and function of pig OCT4 (POU5F1) enhancer in porcine early embryo development. OCT4 is one of the master regulators for the pluripotency of early mammalian embryonic development and embryonic stem cells. It has two regulatory elements: distal enhancer (DE) and proximal enhancer (PE) in the upstream regulatory region. They are activated under different conditions such as naïve and primed. It is known that two enhancers are activated to produce OCT4 simultaneously or sequentially depending on the state of pluripotency. Many porcine OCT4 upstream region-based reporter systems have been reported because this is a necessary part of studying porcine-specific pluripotency. However, the porcine-specific OCT4 reporter system has never been transfected and functionally tested during porcine early embryo development. We performed functional tests of the previously established porcine-specific OCT4 reporter system in the early embryo development stage. Porcine embryos were micro-injected with the pOCT4-ΔPE-eGFP (DE-GFP) containing a distal enhancer and core promoter and pOCT4-ΔDE-DsRed2 (PE-RFP) containing a proximal enhancer and core promoter. They were cultured in PZM-3 at 39°C in a humidified atmosphere, 5% CO2, and 5% O2 for 168h. Fifty of the 100 embryos were injected with OCT4 reporter system as treatment groups and the other 50 were not injected (control groups). We analysed mRNA and protein expression of GFP and RFP using quantitative real-time PCR and confocal microscopy by developmental stages. The introduced reporter system could function beginning with the 4-cell stage. The expression of GFP and RFP was observed simultaneously in the early embryonic development stage up to blastocyst, indicating that porcine OCT4 was produced by distal and proximal enhancers, unlike mouse Oct4 expression, which was only controlled by the distal enhancer during early embryo development. Therefore, the mechanisms and functions of distal and proximal enhancers of porcine OCT4 were different from those of the mouse. This is similar to results of the previous experiment using porcine-induced pluripotent stem cells, which suggest that porcine OCT4 is expressed by two enhancers and in a stage-specific manner during reprogramming and that pigs do not use only one enhancer in pluripotent states, but two enhancers at the same time, and there is only a difference in degree. This work showed that the porcine OCT4 reporter system enables non-destructive analysis during early embryo development and it could be applied to study species-specific pluripotency and to help the establishment of naïve embryonic stem cells in the pig. This work was supported by the BK21 Plus Program, the National Research Foundation of Korea (NRF) grant funded by the Korea government (NRF-2019R1C1C1004514), the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture and Forestry (IPET) through the Development of High Value-Added Food Technology Program funded by the Ministry of Agriculture, Food, and Rural Affairs (MAFRA; 118042-03-3-HD020).

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Minor Splicing Factors Zrsr1 and Zrsr2 Essential for Gametogenesis, Early Embryo Development and Conversion of Stem Cells into 2C-Like

SSRN Electronic Journal ◽

10.2139/ssrn.3367197 ◽

2019 ◽

Author(s):

Isabel Gómez-Redondo ◽

Priscila Ramos-Ibeas ◽

Eva Pericuesta ◽

Benjamín Planells ◽

Raul Fernández-González ◽

...

Keyword(s):

Stem Cells ◽

Embryo Development ◽

Early Embryo ◽

Splicing Factors ◽

Early Embryo Development

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LIN28 coordinately promotes nucleolar/ribosomal functions and represses the 2C-like transcriptional program in pluripotent stem cells

Protein & Cell ◽

10.1007/s13238-021-00864-5 ◽

2021 ◽

Author(s):

Zhen Sun ◽

Hua Yu ◽

Jing Zhao ◽

Tianyu Tan ◽

Hongru Pan ◽

...

Keyword(s):

Stem Cells ◽

Embryo Development ◽

Pluripotent Stem Cells ◽

Rna Binding ◽

Stem Cell Differentiation ◽

Early Embryo ◽

Transcriptional Program ◽

Cell Stage ◽

Early Embryo Development ◽

Nucleolar Stress

AbstractLIN28 is an RNA binding protein with important roles in early embryo development, stem cell differentiation/reprogramming, tumorigenesis and metabolism. Previous studies have focused mainly on its role in the cytosol where it interacts with Let-7 microRNA precursors or mRNAs, and few have addressed LIN28’s role within the nucleus. Here, we show that LIN28 displays dynamic temporal and spatial expression during murine embryo development. Maternal LIN28 expression drops upon exit from the 2-cell stage, and zygotic LIN28 protein is induced at the forming nucleolus during 4-cell to blastocyst stage development, to become dominantly expressed in the cytosol after implantation. In cultured pluripotent stem cells (PSCs), loss of LIN28 led to nucleolar stress and activation of a 2-cell/4-cell-like transcriptional program characterized by the expression of endogenous retrovirus genes. Mechanistically, LIN28 binds to small nucleolar RNAs and rRNA to maintain nucleolar integrity, and its loss leads to nucleolar phase separation defects, ribosomal stress and activation of P53 which in turn binds to and activates 2C transcription factor Dux. LIN28 also resides in a complex containing the nucleolar factor Nucleolin (NCL) and the transcriptional repressor TRIM28, and LIN28 loss leads to reduced occupancy of the NCL/TRIM28 complex on the Dux and rDNA loci, and thus de-repressed Dux and reduced rRNA expression. Lin28 knockout cells with nucleolar stress are more likely to assume a slowly cycling, translationally inert and anabolically inactive state, which is a part of previously unappreciated 2C-like transcriptional program. These findings elucidate novel roles for nucleolar LIN28 in PSCs, and a new mechanism linking 2C program and nucleolar functions in PSCs and early embryo development.

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Geminin deletion in mouse oocytes results in impaired embryo development and reduced fertility

Molecular Biology of the Cell ◽

10.1091/mbc.e15-06-0346 ◽

2016 ◽

Vol 27 (5) ◽

pp. 768-775 ◽

Cited By ~ 8

Author(s):

Xue-Shan Ma ◽

Fei Lin ◽

Zhong-Wei Wang ◽

Meng-Wen Hu ◽

Lin Huang ◽

...

Keyword(s):

Embryo Development ◽

Primordial Follicle ◽

Early Embryo ◽

Cell Cycle Checkpoint ◽

Low Fertility ◽

Early Embryo Development ◽

Damage Repair ◽

Cycle Checkpoint ◽

Oocyte Meiotic Maturation ◽

Zygote Stage

Geminin controls proper centrosome duplication, cell division, and differentiation. We investigated the function of geminin in oogenesis, fertilization, and early embryo development by deleting the geminin gene in oocytes from the primordial follicle stage. Oocyte-specific disruption of geminin results in low fertility in mice. Even though there was no evident anomaly of oogenesis, oocyte meiotic maturation, natural ovulation, or fertilization, early embryo development and implantation were impaired. The fertilized eggs derived from mutant mice showed developmental delay, and many were blocked at the late zygote stage. Cdt1 protein was decreased, whereas Chk1 and H2AX phosphorylation was increased, in fertilized eggs after geminin depletion. Our results suggest that disruption of maternal geminin may decrease Cdt1 expression and cause DNA rereplication, which then activates the cell cycle checkpoint and DNA damage repair and thus impairs early embryo development.

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