Cell differentiation in isolated inner cell masses of mouse blastocysts in vitro: onset of specific gene expression

Development ◽  
1979 ◽  
Vol 53 (1) ◽  
pp. 367-379
Author(s):  
Marie Dziadek

Inner cell masses (ICMs) were isolated by immunosurgery from giant blastocysts formedby the aggregation of three morulae. A layer of endoderm cells formed on the outer surface of these primary ICMs in vitro. When this layer was removed by immunosurgery, a secondary endoderm layer formed. Alphafetoprotein (AFP) was used as a biochemical marker tocharacterize visceral endoderm formation in these cultured ICMs. The immunoperoxidase reaction on sections of ICMs cultured for intervals up to 120 h in vitro showed that someprimary endoderm cells contained AFP, but these were always in the minority. The secondary endoderm layer, on the other hand, was composed of predominantly AFP-positive cells.Itis concluded that the primary endoderm contains mainly parietal endoderm cells, while the secondary layer contains visceral endoderm cells. A model is proposed for the consecutive differentiation of parietal and visceral endoderm cell types from the ICM of mouseblastocysts.


Development ◽  
1997 ◽  
Vol 124 (2) ◽  
pp. 279-287 ◽  
Author(s):  
S.A. Duncan ◽  
A. Nagy ◽  
W. Chan

Immediately prior to gastrulation the murine embryo consists of an outer layer of visceral endoderm (VE) and an inner layer of ectoderm. Differentiation and migration of the ectoderm then occurs to produce the three germ layers (ectoderm, embryonic endoderm and mesoderm) from which the fetus is derived. An indication that the VE might have a critical role in this process emerged from studies of Hnf-4(−/−) mouse embryos which fail to undergo normal gastrulation. Since expression of the transcription factor HNF-4 is restricted to the VE during this phase of development, we proposed that HNF-4-regulated gene expression in the VE creates an environment capable of supporting gastrulation. To address this directly we have exploited the versatility of embryonic stem (ES) cells which are amenable to genetic manipulation and can be induced to form VE in vitro. Moreover, embryos derived solely from ES cells can be generated by aggregation with tetraploid morulae. Using Hnf-4(−/−) ES cells we demonstrate that HNF-4 is a key regulator of tissue-specific gene expression in the VE, required for normal expression of secreted factors including alphafetoprotein, apolipoproteins, transthyretin, retinol binding protein, and transferrin. Furthermore, specific complementation of Hnf-4(−/−) embryos with tetraploid-derived Hnf-4(+/+) VE rescues their early developmental arrest, showing conclusively that a functional VE is mandatory for gastrulation.



2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Daniel Richard Zeve ◽  
Eric Stas ◽  
Manasvi S Shah ◽  
David T Breault

Abstract Enteroendocrine (EE) cells are the most abundant hormone-producing cells in the human body and are vital for metabolism, as well as intestinal and pancreatic function. They have been implicated in the pathogenesis of multiple diseases including diabetes mellitus. Although recent studies have identified multiple signaling pathways (including Wnt, MAPK, BMP and Notch) that can induce low levels of EE cell differentiation, the production of functional human EE cells in vitro remains challenging, making their study and therapeutic utilization difficult. To improve this, we employed the human intestinal organoid culturing system, as it mimics intestinal epithelial homeostasis, allowing for differentiation of multiple epithelial cell types. Using a small scale, directed screen, we targeted multiple transcriptional regulators, using small molecules known to control pancreatic and intestinal development, and hormone production. We chose small molecules instead of gene editing tools to avoid the potential pitfall of off-target mutagenesis. We found that inhibition of FoxO1 in our organoid culture led to an increase in EE cell differentiation as assessed by EE-specific gene expression, with a 5-10 fold upregulation in expression of ChgA, NeuroD1, and Neurog3 compared to whole mucosal biopsies (P<0.01 for all targets, n=3 per group). Flow cytometry data showed 6-8% of cells produced CHGA, compared to 0.2% in undifferentiated organoids (P<0.0001, n=3 per group), and the 1% typically seen in the duodenum. We also noted a corresponding increase in the production of EE hormones, including glucose-dependent insulinotropic peptide (GIP), serotonin and somatostatin, by qPCR and immunofluorescence. Analysis of conditioned media using ELISA, compared to undifferentiated organoids, revealed increased serotonin (362.6±52.3 vs 167.5±5.1 ng/mL, P=.0037, n=3 per group) and GIP (5.76±1.31 pg/mL vs undetectable, n=3 per group). Independently, upregulation of GATA4-Nkx2.5 also induced EE cell differentiation and hormone production, although to a lesser extent than FoxO1 inhibition. The exception to this was GIP, which showed increased expression and production with GATA4-Nkx2.5 compared to FoxO1 inhibition (20.8±7.4 vs 5.8±1.3 pg/mL, n=3 per group), with a much larger increase when FoxO1 inhibition was followed by GATA4-Nkx2.5 activation (53.4±4.8 pg/mL, n=3). Of note, all experiments were performed in a minimum of three human lines. Taken together, our data have identified multiple factors, including inhibition of FoxO1 and activation of GATA4-Nkx2.5, that can drive ex vivo human EE cell differentiation, with unique hormone production profiles, when targeted via small molecules. This is a critical first step towards understanding the role of enteroendocrine cells in disease and the development of EE cell-based therapies.



2005 ◽  
Vol 275 (1-2) ◽  
pp. 215-221 ◽  
Author(s):  
Tieqiao Wen ◽  
Hailong Li ◽  
Hongsheng Song ◽  
Fuxue Chen ◽  
Cuiping Zhao ◽  
...  


Author(s):  
K.U. Sprague ◽  
D. Morton ◽  
D. Larson

Our laboratory is interested in the regulation of gene expression during eukaryotic development. Among the genes we are currently studying are those coding for alanine tRNA in the silkworm, Bombyx mori. These genes are particularly interesting because one Bombyx alanine tRNA species is constitutive -- that is, it is found in a variety of cell types -- while the other major alanine tRNA appears only in the silkgland. The silkgland-specific tRNA predominates when the highly specialized cells of this tissue are synthesizing large amounts of the alanine-rich silk protein, fibroin. The nucleotide sequences of the two alanine tRNAs indicates that they are encoded by different genes.Our goal is to understand the molecular mechanisms governing the differential expression of Bombyx tRNAAla genes. Our approach is to isolate the genes with molecular cloning techniques, and to transcribe and process them in vitro. We have cloned 14 different genomic DNA fragments containing tRNAAla genes, and have developed faithful transcription systems from several different Bombyx tissues, including silkgland.



2018 ◽  
Vol 18 (4) ◽  
pp. 246-255 ◽  
Author(s):  
Lara Termini ◽  
Enrique Boccardo

In vitro culture of primary or established cell lines is one of the leading techniques in many areas of basic biological research. The use of pure or highly enriched cultures of specific cell types obtained from different tissues and genetics backgrounds has greatly contributed to our current understanding of normal and pathological cellular processes. Cells in culture are easily propagated generating an almost endless source of material for experimentation. Besides, they can be manipulated to achieve gene silencing, gene overexpression and genome editing turning possible the dissection of specific gene functions and signaling pathways. However, monolayer and suspension cultures of cells do not reproduce the cell type diversity, cell-cell contacts, cell-matrix interactions and differentiation pathways typical of the three-dimensional environment of tissues and organs from where they were originated. Therefore, different experimental animal models have been developed and applied to address these and other complex issues in vivo. However, these systems are costly and time consuming. Most importantly the use of animals in scientific research poses moral and ethical concerns facing a steadily increasing opposition from different sectors of the society. Therefore, there is an urgent need for the development of alternative in vitro experimental models that accurately reproduce the events observed in vivo to reduce the use of animals. Organotypic cultures combine the flexibility of traditional culture systems with the possibility of culturing different cell types in a 3D environment that reproduces both the structure and the physiology of the parental organ. Here we present a summarized description of the use of epithelial organotypic for the study of skin physiology, human papillomavirus biology and associated tumorigenesis.



BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Wiruntita Chankeaw ◽  
Sandra Lignier ◽  
Christophe Richard ◽  
Theodoros Ntallaris ◽  
Mariam Raliou ◽  
...  

Abstract Background A number of studies have examined mRNA expression profiles of bovine endometrium at estrus and around the peri-implantation period of pregnancy. However, to date, these studies have been performed on the whole endometrium which is a complex tissue. Consequently, the knowledge of cell-specific gene expression, when analysis performed with whole endometrium, is still weak and obviously limits the relevance of the results of gene expression studies. Thus, the aim of this study was to characterize specific transcriptome of the three main cell-types of the bovine endometrium at day-15 of the estrus cycle. Results In the RNA-Seq analysis, the number of expressed genes detected over 10 transcripts per million was 6622, 7814 and 8242 for LE, GE and ST respectively. ST expressed exclusively 1236 genes while only 551 transcripts were specific to the GE and 330 specific to LE. For ST, over-represented biological processes included many regulation processes and response to stimulus, cell communication and cell adhesion, extracellular matrix organization as well as developmental process. For GE, cilium organization, cilium movement, protein localization to cilium and microtubule-based process were the only four main biological processes enriched. For LE, over-represented biological processes were enzyme linked receptor protein signaling pathway, cell-substrate adhesion and circulatory system process. Conclusion The data show that each endometrial cell-type has a distinct molecular signature and provide a significantly improved overview on the biological process supported by specific cell-types. The most interesting result is that stromal cells express more genes than the two epithelial types and are associated with a greater number of pathways and ontology terms.



2004 ◽  
Vol 16 (2) ◽  
pp. 87 ◽  
Author(s):  
Le Ann Blomberg ◽  
Kurt A. Zuelke

Functional genomics provides a powerful means for delving into the molecular mechanisms involved in pre-implantation development of porcine embryos. High rates of embryonic mortality (30%), following either natural mating or artificial insemination, emphasise the need to improve the efficiency of reproduction in the pig. The poor success rate of live offspring from in vitro-manipulated pig embryos also hampers efforts to generate transgenic animals for biotechnology applications. Previous analysis of differential gene expression has demonstrated stage-specific gene expression for in vivo-derived embryos and altered gene expression for in vitro-derived embryos. However, the methods used to date examine relatively few genes simultaneously and, thus, provide an incomplete glimpse of the physiological role of these genes during embryogenesis. The present review will focus on two aspects of applying functional genomics research strategies for analysing the expression of genes during elongation of pig embryos between gestational day (D) 11 and D12. First, we compare and contrast current methodologies that are being used for gene discovery and expression analysis during pig embryo development. Second, we establish a paradigm for applying serial analysis of gene expression as a functional genomics tool to obtain preliminary information essential for discovering the physiological mechanisms by which distinct embryonic phenotypes are derived.



2008 ◽  
Vol 22 (12) ◽  
pp. 2677-2688 ◽  
Author(s):  
Paul G. Tiffen ◽  
Nader Omidvar ◽  
Nuria Marquez-Almuina ◽  
Dawn Croston ◽  
Christine J. Watson ◽  
...  

Abstract Recent studies in breast cancer cell lines have shown that oncostatin M (OSM) not only inhibits proliferation but also promotes cell detachment and enhances cell motility. In this study, we have looked at the role of OSM signaling in nontransformed mouse mammary epithelial cells in vitro using the KIM-2 mammary epithelial cell line and in vivo using OSM receptor (OSMR)-deficient mice. OSM and its receptor were up-regulated approximately 2 d after the onset of postlactational mammary regression, in response to leukemia inhibitory factor (LIF)-induced signal transducer and activator of transcription-3 (STAT3). This resulted in sustained STAT3 activity, increased epithelial apoptosis, and enhanced clearance of epithelial structures during the remodeling phase of mammary involution. Concurrently, OSM signaling precipitated the dephosphorylation of STAT5 and repressed expression of the milk protein genes β-casein and whey acidic protein (WAP). Similarly, during pregnancy, OSM signaling suppressed β-casein and WAP gene expression. In vitro, OSM but not LIF persistently down-regulated phosphorylated (p)-STAT5, even in the continued presence of prolactin. OSM also promoted the expression of metalloproteinases MMP3, MMP12, and MMP14, which, in vitro, were responsible for OSM-specific apoptosis. Thus, the sequential activation of IL-6-related cytokines during mammary involution culminates in an OSM-dependent repression of epithelial-specific gene expression and the potentiation of epithelial cell extinction mediated, at least in part, by the reciprocal regulation of p-STAT5 and p-STAT3.



1992 ◽  
Vol 12 (3) ◽  
pp. 1202-1208
Author(s):  
R A Graves ◽  
P Tontonoz ◽  
B M Spiegelman

The molecular basis of adipocyte-specific gene expression is not well understood. We have previously identified a 518-bp enhancer from the adipocyte P2 gene that stimulates adipose-specific gene expression in both cultured cells and transgenic mice. In this analysis of the enhancer, we have defined and characterized a 122-bp DNA fragment that directs differentiation-dependent gene expression in cultured preadipocytes and adipocytes. Several cis-acting elements have been identified and shown by mutational analysis to be important for full enhancer activity. One pair of sequences, ARE2 and ARE4, binds a nuclear factor (ARF2) present in extracts derived from many cell types. Multiple copies of these elements stimulate gene expression from a minimal promoter in preadipocytes, adipocytes, and several other cultured cell lines. A second pair of elements, ARE6 and ARE7, binds a separate factor (ARF6) that is detected only in nuclear extracts derived from adipocytes. The ability of multimers of ARE6 or ARE7 to stimulate promoter activity is strictly adipocyte specific. Mutations in the ARE6 sequence greatly reduce the activity of the 518-bp enhancer. These data demonstrate that several cis- and trans-acting components contribute to the activity of the adipocyte P2 enhancer and suggest that ARF6, a novel differentiation-dependent factor, may be a key regulator of adipogenic gene expression.



2005 ◽  
Vol 289 (6) ◽  
pp. G1091-G1099 ◽  
Author(s):  
Kazunobu Nonome ◽  
Xiao-Kang Li ◽  
Terumi Takahara ◽  
Yusuke Kitazawa ◽  
Naoko Funeshima ◽  
...  

Human umbilical cord blood (HUCB) contains stem/progenitor cells, which can differentiate into a variety of cell types. In this study, we investigated whether HUCB cells differentiate into hepatocytes in vitro and in vivo. We also examined whether CD34 could be the selection marker of stem cells for hepatocytes. HUCB cells were obtained from normal full-term deliveries, and CD34+/−cells were further separated. For in vitro study, HUCB cells were cultured for 4 wk, and expressions of liver-specific genes were examined. For the in vivo study, nonobese diabetic/severe combined immunodeficient mice were subjected to liver injury by a Fas ligand-carried adenoviral vector or only radiated. Mice were treated simultaneously with or without cell transplantation of HUCB, CD34+, or CD34−cells. After 4 wk, human-specific gene/protein expression was examined. In the in vitro study, human liver-specific genes were positive after 7 days of culture. The immunofluorescent study showed positive staining of α-fetoprotein, cytokeratin 19, and albumin in round-shaped cells. In the in vivo study, immunohistochemical analysis showed human albumin-positive, hepatocyte-specific antigen-positive cells in mouse livers of the Fas ligand/transplantation group. Fluorescence in situ hybridization analysis using the human Y chromosome also showed positive signals. However, no difference between transplanted cell types was detected. In contrast, immunopositive cells were not detected in the irradiated/transplantation group. The RT-PCR result also showed human hepatocyte-specific gene expressions only in the Fas ligand/transplantation group. HUCB cells differentiated into hepatocyte-like cells in the mouse liver, and liver injury was essential during this process. The differences between CD34+and CD34−cells were not observed in human hepatocyte-specific expression.



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