scholarly journals Enucleation-Induced Rat Adrenal Gland Regeneration: Expression Profile of Selected Genes Involved in Control of Adrenocortical Cell Proliferation

2014 ◽  
Vol 2014 ◽  
pp. 1-13 ◽  
Author(s):  
Marianna Tyczewska ◽  
Marcin Rucinski ◽  
Agnieszka Ziolkowska ◽  
Marta Szyszka ◽  
Marcin Trejter ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Growth Arrest ◽  
Cyclin B1 ◽  
Adrenocortical Cell ◽  
Priming Effects ◽  
Rna Analysis ◽  
Expression Of Genes ◽  
Rat Adrenals ◽  
Early Transcription ◽  
Degree Of Similarity

Enucleation-induced adrenal regeneration is a highly controlled process; however, only some elements involved in this process have been recognized. Therefore, we performed studies on regenerating rat adrenals. Microarray RNA analysis and QPCR revealed that enucleation resulted in a rapid elevation of expression of genes involved in response to wounding, defense response, and in immunological processes. Factors encoded by these genes obscure possible priming effects of various cytokines on initiation of regeneration. In regenerating adrenals we identified over 100 up- or downregulated genes involved in adrenocortical cell proliferation. The changes were most significant at days 2-3 after enucleation and their number decreased during regeneration. For example, expression analysis revealed a notable upregulation of the growth arrest gene, Gadd45, only 24 hours after surgery while expression of cyclin B1 and Cdk1 genes was notably elevated between days 1–8 of regeneration. These changes were accompanied by changes in expression levels of numerous growth factors and immediate-early transcription factors genes. Despite notable differences in mechanisms of adrenal and liver regeneration, in regenerating adrenals we identified genes, the expression of which is well recognized in regenerating liver. Thus, it seems legitimate to suggest that, in the rat, the general model of liver and adrenal regeneration demonstrate some degree of similarity.

The Role of Retinoblastoma Protein in Cell Cycle Regulation: An Updated Review

2021 ◽  
Vol 20 ◽  
Author(s):  
Rabih Roufayel ◽  
Rabih Mezher ◽  
Kenneth B. Storey
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Transcription Factors ◽  
Cell Cycle Control ◽  
Expression Of Genes ◽  
E2f Transcription Factor ◽  
Cellular Energetics ◽  
Development And Differentiation ◽  
E2f Transcription Factors ◽  
Rb Phosphorylation

: Selected transcription factors have critical roles to play in organism survival by regulating the expression of genes that control the adaptations needed to handle stress conditions. The retinoblastoma (Rb) protein coupled with the E2F transcription factor family was demonstrated to have roles in controlling the cell cycle during freezing and associated environmental stresses (anoxia, dehydration). Rb phosphorylation or acetylation at different sites provide a mechanism for repressing cell proliferation that is under the control of E2F transcription factors in animals facing stresses that disrupt cellular energetics or cell volume controls. Other central regulators of the cell cycle including Cyclins, Cyclin dependent kinases (Cdks), and checkpoint proteins detect DNA damage or any improper replication, blocking further progression of cell cycle and interrupting cell proliferation. This review provides an insight into the molecular regulatory mechanisms of cell cycle control, focusing on Rb-E2F along with Cyclin-Cdk complexes typically involved in development and differentiation that need to be regulated in order to survive extreme cellular stress.

scholarly journals BMP Activity Is Required for Tooth Development from the Lamina to Bud Stage

2012 ◽  
Vol 91 (7) ◽  
pp. 690-695 ◽  
Author(s):  
Y. Wang ◽  
L. Li ◽  
Y. Zheng ◽  
G. Yuan ◽  
G. Yang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Molecular Marker ◽  
Tooth Development ◽  
Tooth Germ ◽  
Bmp Signaling ◽  
Expression Of Genes ◽  
Dental Epithelium ◽  
Initiation Stage ◽  
Transgenic Embryos ◽  
Bmp Antagonist

Several Bmp genes are expressed in the developing mouse tooth germ from the initiation to the late-differentiation stages, and play pivotal roles in multiple steps of tooth development. In this study, we investigated the requirement of BMP activity in early tooth development by transgenic overexpression of the extracellular BMP antagonist Noggin. We show that overexpression of Noggin in the dental epithelium at the tooth initiation stage arrests tooth development at the lamina/early-bud stage. This phenotype is coupled with a significantly reduced level of cell proliferation rate and a down-regulation of Cyclin-D1 expression, specifically in the dental epithelium. Despite unaltered expression of genes known to be implicated in early tooth development in the dental mesenchyme and dental epithelium of transgenic embryos, the expression of Pitx2, a molecular marker for the dental epithelium, became down-regulated, suggesting the loss of odontogenic fate in the transgenic dental epithelium. Our results reveal a novel role for BMP signaling in the progression of tooth development from the lamina stage to the bud stage by regulating cell proliferation and by maintaining odontogenic fate of the dental epithelium.

Integrated control of cell proliferation and cell death by the c- myc oncogene

1994 ◽  
Vol 345 (1313) ◽  
pp. 269-275 ◽  
Keyword(s):  
Cell Proliferation ◽  
Cell Death ◽  
Transcriptional Activation ◽  
Dynamic Equilibrium ◽  
Growth Arrest ◽  
Deletion Mapping ◽  
Potent Inducer ◽  
Cellular Environment ◽  
Induction Of Apoptosis ◽  
Induced Apoptosis

Regulation of multicellular architecture involves a dynamic equilibrium between cell proliferation, differentiation with consequent growth arrest, and cell death. Apoptosis is one particular form of active cell death that is extremely rapid and characterized by auto-destruction of chromatin, cellular blebbing and condensation, and vesicularization of internal components. The c- myc proto-oncogene encodes an essential component of the cell’s proliferative machinery and its deregulated expression is implicated in most neoplasms. Intriguingly, c- myc can also act as a potent inducer of apoptosis. Myc-induced apoptosis occurs only in cells deprived of growth factors or forcibly arrested with cytostatic drugs. Myc-induced apoptosis is dependent upon the level at which it is expressed and deletion mapping shows that regions of c-Myc required for apoptosis overlap with regions necessary for co-transformation, autoregulation, inhibition of differentiation, transcriptional activation and sequence-specific DNA binding. Moreover, induction of apoptosis by c-Myc requires association with c-Myc’s heterologous partner, Max. All of this strongly implies that c-Myc drives apoptosis through a transcriptional mechanism: presumably by modulation of target genes. Two simple models can be invoked to explain the induction of apoptosis by c-Myc. One holds that death arises from a conflict in growth signals which is generated by the inappropriate or unscheduled expression of c-Myc under conditions that would normally promote growth arrest. In this ‘Conflict’ model, induction of apoptosis is not a normal function of c-Myc but a pathological manifestation of its deregulation. It thus has significance only for models of carcinogenic progression in which myc genes are invariably disrupted. The other model holds that induction of apoptosis is a normal obligate function of c-Myc which is modulated by specific survival factors. Thus, every cell that enters the cycle invokes an obligate abort suicide pathway which must be continuously suppressed by signals from the immediate cellular environment for the proliferating cell to survive. Evidence will be presented supporting this second ‘Dual Signal’ model for cell growth and survival, and its widespread implications will be discussed.

scholarly journals Jagged1/Notch3 Signaling Modulates Hemangioma-Derived Pericyte Proliferation and Maturation

2016 ◽  
Vol 40 (5) ◽  
pp. 895-907 ◽  
Author(s):  
Yi Ji ◽  
Siyuan Chen ◽  
Bo Xiang ◽  
Yuan Li ◽  
Li Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Growth Arrest ◽  
Notch Signaling Pathway ◽  
Cell Growth Arrest ◽  
Muscle Myosin ◽  
Dependent Mechanism

Background: The Notch signaling pathway has been implicated in the pericyte phenotype, but its exact roles in hemangioma-derived pericytes (Hem-pericytes) remain ill defined. Methods: Hem-pericytes were stimulated by immobilized recombinant Jagged1. The potential mechanisms of Notch-induced Hem-pericytes growth arrest were investigated by cell cycle assay, and the role of the Notch in promoting Hem-pericyte maturation was also analyzed by real-time PCR and western blot. Results: Activation of Notch3 in Hem-pericytes significantly reduced cell proliferation and inhibited cell cycle transition. This event was associated with an increase in the levels of p21Cip1. Knockdown of p21Cip1 resulted in a significant rescue of Notch-induced cell growth arrest and an entry into the cell cycle. We showed that Jagged1 activation of Notch3 signaling upregulated the expression of the pericyte contractile markers smooth muscle myosin heavy chain (smMHC) and α-smooth muscle actin (αSMA), concomitant with an increase in the expression of myocardin in Hem-pericytes. We further revealed that the endothelial-derived Jagged1 modulated the Hem-pericyte phenotype via a contact-dependent mechanism. Conclusions: Our results demonstrated that Jagged1 activation of Notch3 resulted in a significant decrease in cell proliferation while concomitantly promoting Hem-pericyte maturation. These data provide initial evidence that Notch induces a quiescent phenotype in Hem-pericytes.

HDAC1 overexpression enhances β-cell proliferation by down-regulating Cdkn1b/p27

2018 ◽  
Vol 475 (24) ◽  
pp. 3997-4010 ◽  
Author(s):  
Carrie Draney ◽  
Matthew C. Austin ◽  
Aaron H. Leifer ◽  
Courtney J. Smith ◽  
Kyle B. Kener ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Survival ◽  
Cell Mass ◽  
Cyclin B1 ◽  
Β Cell ◽  
Histone Deacetylase 1 ◽  
Cell Cycle Inhibitor ◽  
Homeobox Transcription Factor ◽  
Glucose Stimulated Insulin Secretion

The homeobox transcription factor Nkx6.1 is sufficient to increase functional β-cell mass, where functional β-cell mass refers to the combination of β-cell proliferation, glucose-stimulated insulin secretion (GSIS) and β-cell survival. Here, we demonstrate that the histone deacetylase 1 (HDAC1), which is an early target of Nkx6.1, is sufficient to increase functional β-cell mass. We show that HDAC activity is necessary for Nkx6.1-mediated proliferation, and that HDAC1 is sufficient to increase β-cell proliferation in primary rat islets and the INS-1 832/13 β-cell line. The increase in HDAC1-mediated proliferation occurs while maintaining GSIS and increasing β-cell survival in response to apoptotic stimuli. We demonstrate that HDAC1 overexpression results in decreased expression of the cell cycle inhibitor Cdkn1b/p27 which is essential for inhibiting the G1 to S phase transition of the cell cycle. This corresponds with increased expression of key cell cycle activators, such as Cyclin A2, Cyclin B1 and E2F1, which are activated by activation of the Cdk4/Cdk6/Cyclin D holoenzymes due to down-regulation of Cdkn1b/p27. Finally, we demonstrate that overexpression of Cdkn1b/p27 inhibits HDAC1-mediated β-cell proliferation. Our data suggest that HDAC1 is critical for the Nkx6.1-mediated pathway that enhances functional β-cell mass.

scholarly journals Deficiency of G9a Inhibits Cell Proliferation and Activates Autophagy via Transcriptionally Regulating c-Myc Expression in Glioblastoma

2020 ◽  
Vol 8 ◽  
Author(s):  
Xiao Xue Ke ◽  
Rui Zhang ◽  
Xi Zhong ◽  
Lei Zhang ◽  
Hongjuan Cui
Keyword(s):  
Cell Proliferation ◽  
Cyclin B1 ◽  
Luciferase Reporter ◽  
Cycle Arrest ◽  
Histone Lysine Methyltransferase ◽  
Lysine Methyltransferase ◽  
A Cell ◽  
Cell Proliferation Control

Glioblastoma is an aggressive and difficult to treat cancer. Recent data have emerged implicating that histone modification level may play a crucial role in glioma genesis. The histone lysine methyltransferase G9a is mainly responsible for the mono- and di-methylation of histone H3 lysine 9 (H3K9), whose overexpression is associated with a more aggressive phenotype in cancer. However, the detailed correlations between G9a and glioblastoma genesis remain to be further elucidated. Here, we show that G9a is essential for glioblastoma carcinogenesis and reveal a probable mechanism of it in cell proliferation control. We found that G9a was highly expressed in glioblastoma cells, and knockdown or inhibition of G9a significantly repressed cell proliferation and tumorigenesis ability both in vitro and in vivo. Besides, knockdown or inhibition of G9a led to a cell cycle arrest in G2 phase, as well as decreased the expression of CDK1, CDK2, Cyclin A2, and Cyclin B1, while it induced the activation of autophagy. Further investigation showed that G9a deficiency induced cell proliferation suppression, and activation of autophagy was rescued by overexpression of the full-length c-Myc. Chromatin immunoprecipitation (ChIP) assay showed that G9a was enriched on the −2267 to −1949 region of the c-Myc promoter in LN-229 cells and the −1949 to −1630 region of the c-Myc promoter in U-87 MG cells. Dual-luciferase reporter assay showed that c-Myc promoter activity was significantly reduced after knockdown or inhibition of G9a. Our study shows that G9a controls glioblastoma cell proliferation by transcriptionally modulating oncogene c-Myc and provides insight into the capabilities of G9a working as a potential therapeutic target in glioblastoma.

scholarly journals Trophectoderm-Specific Knockdown of LIN28 Decreases Expression of Genes Necessary for Cell Proliferation and Reduces Elongation of Sheep Conceptus

2020 ◽  
Vol 21 (7) ◽  
pp. 2549 ◽  
Author(s):  
Asghar Ali ◽  
Mark Stenglein ◽  
Thomas Spencer ◽  
Gerrit Bouma ◽  
Russell Anthony ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Critical Period ◽  
In Vitro Experiments ◽  
Placental Development ◽  
Expression Of Genes ◽  
Trophectoderm Cells ◽  
Successful Establishment

LIN28 inhibits let-7 miRNA maturation which prevents cell differentiation and promotes proliferation. We hypothesized that the LIN28-let-7 axis regulates proliferation-associated genes in sheep trophectoderm in vivo. Day 9-hatched sheep blastocysts were incubated with lentiviral particles to deliver shRNA targeting LIN28 specifically to trophectoderm cells. At day 16, conceptus elongation was significantly reduced in LIN28A and LIN28B knockdowns. Let-7 miRNAs were significantly increased and IGF2BP1-3, HMGA1, ARID3B, and c-MYC were decreased in trophectoderm from knockdown conceptuses. Ovine trophoblast (OTR) cells derived from day 16 trophectoderm are a useful tool for in vitro experiments. Surprisingly, LIN28 was significantly reduced and let-7 miRNAs increased after only a few passages of OTR cells, suggesting these passaged cells represent a more differentiated phenotype. To create an OTR cell line more similar to day 16 trophectoderm we overexpressed LIN28A and LIN28B, which significantly decreased let-7 miRNAs and increased IGF2BP1-3, HMGA1, ARID3B, and c-MYC compared to control. This is the first study showing the role of the LIN28-let-7 axis in trophoblast proliferation and conceptus elongation in vivo. These results suggest that reduced LIN28 during early placental development can lead to reduced trophoblast proliferation and sheep conceptus elongation at a critical period for successful establishment of pregnancy.

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