ABSTRACT: Effects of overexpressed Atoh8 on the transcriptional profile of mouse ductal cells mPAC in the absence or presence of co-expressed Neurogenin3
Project description:Atoh8 is a transcription factor of the basic-helix-loop-helix (bHLH) family that is expressed in multiple tissues during embryonic development but whose specific functions remain unknown. The gene encoding Atoh8 is induced by various lineage- determining bHLH transcription factors in cell culture, suggesting a possible common role of this gene in multiple bHLH-driven differentiation programs. In the pancreas, the pro-endocrine bHLH factors Neurogenin3 (Neurog3) and NeuroD1 activate Atoh8 expression. Moreover, Atoh8 is expressed in the embryonic pancreas confirming its participation in the pancreatic transcriptional cascade. This work aims at gaining insight into the molecular function of Atoh8 during the endocrine differentiation program initiated by Neurog3 in the pancreas. To this aim, we have generated a recombinant adenovirus encoding an Atoh8-specific shRNA (Ad-shAtoh8) and used it to down-regulate expression of the Atoh8 gene in Neurog3-expressing pancreatic ductal cells (mPAC), a cellular model of endocrine cell differentiation. Thus, we have compared global changes in gene expression profiles between cells treated with Ad-Neurog3+shControl and cells treated with Ad-Neurog3+shAtoh8 using Affymetrix microarrays. Our results show that Atoh8 silencing significantly affects the expression of 293 genes in Neurog3-expressing mPAC cells. Gene Ontology analysis has revealed cell cycle as the biological function most significantly represented among the modified genes. These results uncover a potential function of Math6 as a regulator of cell cycle progression and provide novel insights into the link between Neurog3 and the regulation of the cell cycle. mPAC cells (mouse pancreatic duct cells) overexpressing Neurogenin3 were divided in 2 groups according to the shRNA encoded by the recombinant adenoviruses used: 1) Scramble shRNA (control for the infection effect), 2) Atonal Homolog 8-specific shRNA. Experiment was performed three independent times (3 independent biological replicates).
Project description:Atoh8 is a transcription factor of the basic-helix-loop-helix (bHLH) family that is expressed in multiple tissues during embryonic development but whose specific functions remain unknown. The gene encoding Atoh8 is induced by various lineage- determining bHLH transcription factors in cell culture, suggesting a possible common role of this gene in multiple bHLH-driven differentiation programs. In the pancreas, the pro-endocrine bHLH factors Neurogenin3 (Neurog3) and NeuroD1 activate Atoh8 expression. Moreover, Atoh8 is expressed in the embryonic pancreas confirming its participation in the pancreatic transcriptional cascade. This work aims at gaining insight into the molecular function of Atoh8 during the endocrine differentiation program initiated by Neurog3 in the pancreas. To this aim, we have generated a recombinant adenovirus encoding an Atoh8-specific shRNA (Ad-shAtoh8) and used it to down-regulate expression of the Atoh8 gene in Neurog3-expressing pancreatic ductal cells (mPAC), a cellular model of endocrine cell differentiation. Thus, we have compared global changes in gene expression profiles between cells treated with Ad-Neurog3+shControl and cells treated with Ad-Neurog3+shAtoh8 using Affymetrix microarrays. Our results show that Atoh8 silencing significantly affects the expression of 293 genes in Neurog3-expressing mPAC cells. Gene Ontology analysis has revealed cell cycle as the biological function most significantly represented among the modified genes. These results uncover a potential function of Math6 as a regulator of cell cycle progression and provide novel insights into the link between Neurog3 and the regulation of the cell cycle.
Project description:The presence of activated pancreatic stellate cells (PSCs) in the pancreatic ductal adenocarcinoma (PDAC) microenvironment plays a significant role in cancer progression. Macrophage migration inhibitory factor (MIF) is overexpressed in PDAC tissues and expressed by both cancer and stromal cells. The expression status of MIF and its receptors in PDAC- associated fibroblasts or PSCs and its pathophysiological roles are yet to be elucidated. The next-generation sequencing technique was adapted to check the effect of MIF absence on the expression of other genes in mice (mPSCs).
Project description:Strain ∆staRPZnstaR was obtained to investigate genome-wide differential gene expresion when staR gene is reppressed or overexpressed by adding Zn to the culture medium. In addition, gene expression profile alterations produced upon inhibition of gyrase with Novobiocin were studied in the absence and presence of StaR.
Project description:The basic helix-loop-helix (bHLH) transcription factors of the Drosophila’s atonal-related superfamily Neurogenin3 (Neurog3) and NeuroD1 promote endocrine differentiation in the gastrointestinal tract. Atonal Homolog 8 (Atoh8/Math6) is a newly identified member of the atonal-related family whose expression is induced by Neurog3 and NeuroD1 in cell culture, indicating a possible role for this gene in the endocrine differentiation program downstream of these two pro-endocrine factors. Intriguingly, available experimental evidence based on a reduced number of genes suggests that Atoh8 may negatively regulate Neurog3-targeting events. In this study, we have analyzed global changes in gene expression profiles upon exogenous expression of Atoh8 alone or in combination with Neurog3 in mouse pancreatic duct (mPAC) cells. These cells activate neuroendocrine-specific gene expression in response to Neurog3 and NeuroD1 and thus serve as an optimal model to evaluate the proendocrine activity of Atoh8. We have compared transcriptional profiles between mPAC cells treated with a recombinant adenovirus expressing Atoh8 (Ad-Atoh8) or a control adenovirus encoding B-galactosidase (Ad-Bgal), and between cells treated with Ad-Neurog3+Ad-Bgal or cells treated with Ad-Neurog3+Ad-Atoh8. The results obtained show that Atoh8 exhibits a very modest transcriptional activity in these cells thus confirming that Atoh8 does not function as a proendocrine gene. Furthermore, our data also confirm the ability of Atoh8 to block Neurog3-dependent transcriptional activation events. However, since repression is only seen for a small subset of Neurog3 gene targets, we discard a general role of Atoh8 as a negative regulator of Neurog3 pro-endocrine activity.
Project description:To investigate the effects of CEBPD on pancreatic ductal cell tumorigenicity, we established doxycycline-inducible MIA PaCa-2 cells for CEBPD over-expression, as well as non-control cells with an empty inducible construct. RNAseq was performed on these cells in the presence and absence of doxycycline and we showed that CEBPD activates gene signatures associated with cell motility.
Project description:To identify ATOH8 and SMAD3 form a novel transcriptional complex, we performed chromatin immunoprecipitation followed by sequencing (ChIP-seq). Analyses of their genome occupancy profiling reveals that their genome-wide binding patterns are highly similar and they co-occupy a number of same genes. CCNE2 and CDK1 are their common downstream target genes.
Project description:The aim was to study the transcriptional profiling of the E. faecalis V583 in presence and absence of tyrosine. We compared the expression profile of the strains grown in M17 medium with glucose as carbon source (GM17) and suplemented with agmatine in presence and absence of tyrosine.
Project description:Ferroptosis, a non-apoptotic programmed cell death triggered by excessive iron-dependent lipid peroxidation, plays a pivotal role in tumor progression. Significant progress has been made in elucidating the role of transcription factors in the regulation of ferroptosis. Nevertheless, the identification of the key transcription factor responsible for inducing ferroptosis remains elusive. In this study, we discovered that ATOH8 is upregulated in prostate cancer cells treated with the ferroptosis inducer. Overexpression of ATOH8 increased the vulnerability of prostate cancer to ferroptosis, while ATOH8 deletion promotes ferroptosis evasion. Mechanistically, ATOH8 suppresses the transcription of SCD, reducing the synthesis of monounsaturated fatty acids that confer resistance to ferroptosis. Additionally, ATOH8 works in conjunction with the E protein E47 to form a transcriptional repression complex that inhibits SCD transcription. Furthermore, we discovered that EZH2 epigenetically suppresses the expression of ATOH8 through DNA methylation and H3K27 methylation. Interestingly, EZH2 was found to be downregulated in ferroptosis, resulting in an upregulation of ATOH8. Pharmacological inhibition of EZH2 combined with ferroptosis inducer significantly suppresses prostate cancer growth in vitro and in vivo. Together, our findings unveil that EZH2-mediated ATOH8 downregulation promotes ferroptosis evasion and suggest that pharmacological manipulation of EZH2 and ATOH8 is a promising therapeutic strategy for prostate cancer.