scholarly journals Pdx-1 Is Not Sufficient for Repression of Proglucagon Gene Transcription in Islet or Enteroendocrine Cells

Endocrinology ◽  
2005 ◽  
Vol 146 (1) ◽  
pp. 441-449 ◽  
Author(s):  
Grace Flock ◽  
Xiemin Cao ◽  
Daniel J. Drucker
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Nuclear Translocation ◽  
Immunohistochemical Analysis ◽  
Enteroendocrine Cells ◽  
Cell Phenotype ◽  
Protein Overexpression ◽  
Adenoviral Transduction ◽  
Glucagon Like Peptide 1 ◽  
The Relationship

Pdx-1 plays a key role in the development of the pancreas and the control of islet gene transcription and has also been proposed as a dominant regulator of the α- vs. β-cell phenotype via extinction of proglucagon expression. To ascertain the relationship between Pdx-1 and proglucagon gene expression, we examined the effect of enhanced pdx-1 expression on proglucagon gene expression in murine islet αTC-1 and GLUTag enteroendocrine cells. Although adenoviral transduction increased the levels of pdx-1 mRNA transcripts and nuclear Pdx-1 protein, overexpression of pdx-1 did not repress endogenous proglucagon gene expression in αTC-1 or GLUTag cells or murine islets. Immunohistochemical analysis of cells transduced with Ad-pdx-1 demonstrated multiple individual islet or enteroendocrine cells exhibiting both nuclear Pdx-1 and cytoplasmic glucagon-like peptide-1 immunopositivity. The failure of pdx-1 to inhibit endogenous proglucagon gene expression was not attributable to defects in Pdx-1 nuclear translocation or DNA binding as demonstrated using Western blotting and EMSA analyses. Furthermore, Ad-pdx-1 transduction did not repress proglucagon promoter activity in αTC-1 or GLUTag cells. Taken together, these findings demonstrate that pdx-1 alone is not sufficient for specification of the hormonal phenotype or extinction of proglucagon gene expression in islet or enteroendocrine cells.

Interleukin-6 overexpression as a marker of malignancy in human gliomas

2001 ◽  
Vol 94 (1) ◽  
pp. 97-101 ◽  
Author(s):  
Christine Rolhion ◽  
Frédérique Penault-Llorca ◽  
Jean-Louis Kémény ◽  
Jean-Jacques Lemaire ◽  
Christiane Jullien ◽  
...  
Keyword(s):  
Gene Expression ◽  
Interleukin 6 ◽  
Vascular Endothelial Cells ◽  
Immunohistochemical Analysis ◽  
Vascular Endothelial ◽  
Content Type ◽  
Major Interest ◽  
Polymerase Chain ◽  
The Relationship ◽  
Fine Print

Object. Glioblastomas multiforme (GBMs) grow rapidly and are highly resistant to treatment compared with other glioma types and grades. Consequently, it is of major interest to identify markers of aggressiveness in these tumors that could represent new therapeutic targets. Interleukin (IL)—6 is frequently produced in gliomas and, given its manifold properties, could be considered as a candidate marker. Expression of IL-6 may be involved in cell growth, resistance to chemotherapy and radiotherapy (via an antiapoptotic pathway), and angiogenesis. This study was conducted to test this hypotheses and to evaluate the suitability of IL-6 as a target in the treatment of GBMs. Methods. The authors studied the relationship between the level of IL-6 gene expression as assessed using semiquantitative reverse transcription—polymerase chain reaction and by determining various histological types and grades in a series of 59 gliomas. It was found that GBMs displayed a significantly higher level of IL-6 expression than other types of glioma (p < 0.001). Immunohistochemical analysis revealed that IL-6 was produced mainly by malignant cells and a few vascular endothelial cells. Conclusions. It can be inferred from these findings that IL-6 gene expression is related to glioma aggressiveness and that IL-6 may play a central role in GBM behavior. Interleukin-6, therefore, could be considered as a new potential target in the treatment of GBMs.

scholarly journals Parallel changes in nuclear and cytosolic calcium in mouse pancreatic β-cells

1997 ◽  
Vol 325 (3) ◽  
pp. 771-778 ◽  
Author(s):  
Graham R. BROWN ◽  
Martin KÖHLER ◽  
Per-Olof BERGGREN
Keyword(s):  
Gene Transcription ◽  
Cytosolic Calcium ◽  
Pancreatic Β Cell ◽  
Β Cell ◽  
Direct Role ◽  
Glucagon Like Peptide ◽  
Glucagon Like Peptide 1 ◽  
Fast Oscillations ◽  
The Relationship ◽  
Nuclear Processes

In the neuroendocrine pancreatic β-cell, elevations in intracellular Ca2+ lead to insulin secretion and the initiation of gene transcription. However, the relationship between cytosolic and nuclear Ca2+ in these cells is unknown. The Ca2+ permeability of the nuclear membrane would therefore determine if Ca2+ could play a direct role in Ca2+-dependent nuclear processes. Using confocal fluorescence microscopy with the ratiometric Ca2+ indicator indo-1 and carefully correcting for compartmentalized indicator, we now demonstrate that there is no difference between the nuclear Ca2+ concentration and the cytosolic Ca2+ concentration ([Ca2+]c) in the resting β-cell. Slow Ca2+ oscillations induced by glucose, fast oscillations induced by glucagon-like peptide-1 and responses to potassium and carbachol all indicate that changes in cytosolic Ca2+ are reflected within the nucleus. We conclude that there are no restrictions on Ca2+ entry into the nucleus of the pancreatic β-cell subsequent to increases in [Ca2+]c. This implies that any signal involved in increasing [Ca2+]c, and thereby insulin release, may also promote nuclear Ca2+-induced gene transcription.

scholarly journals Aberrant Regulation of Human Intestinal Proglucagon Gene Expression in the NCI-H716 Cell Line

Endocrinology ◽  
2003 ◽  
Vol 144 (5) ◽  
pp. 2025-2033 ◽  
Author(s):  
Xiemin Cao ◽  
Grace Flock ◽  
Caroline Choi ◽  
David M. Irwin ◽  
Daniel J. Drucker
Keyword(s):  
Gene Expression ◽  
Cell Line ◽  
Gene Transcription ◽  
Sodium Butyrate ◽  
Soluble Guanylate Cyclase ◽  
Trichostatin A ◽  
Inhibitory Effect ◽  
P38 Inhibitor ◽  
Glucagon Like Peptide 1 ◽  
Coordinate Changes

Despite interest in understanding glucagon-like peptide-1 (GLP-1) production, the factors important for GLP-1 biosynthesis remain poorly understood. We examined control of human proglucagon gene expression in NCI-H716 cells, a cell line that secretes GLP-1 in a regulated manner. Insulin, phorbol myristate acetate, or forskolin, known regulators of rodent proglucagon gene expression, had no effect, whereas sodium butyrate decreased levels of NCI-H716 proglucagon mRNA transcripts. The inhibitory effect of sodium butyrate was mimicked by trichostatin A but was not detected with sodium acetate or isobutyrate. The actions of butyrate were not diminished by the ERK1/2 inhibitor PD98059, p38 inhibitor SB203580, or soluble guanylate cyclase inhibitor LY83583 or following treatment of cells with KT5823, a selective inhibitor of cGMP-dependent protein kinase. NCI-H716 cells expressed multiple proglucagon gene transcription factors including isl-1, pax-6, pax-2, cdx-2/3, pax-4, hepatocyte nuclear factor (HNF)-3α, HNF-3β, HNF-3γ, and Nkx2.2. Nevertheless, the butyrate-dependent inhibition of proglucagon gene expression was not associated with coordinate changes in transcription factor expression and both the human and rat transfected proglucagon promoters were transcriptionally inactive in NCI-H716 cells. Hence, NCI-H716 cells may not be a physiologically optimal model for studies of human enteroendocrine proglucagon gene transcription.

scholarly journals FoxO1 is not a key transcription factor in the regulation of myostatin (mstn-1a and mstn-1b) gene expression in trout myotubes

2011 ◽  
Vol 301 (1) ◽  
pp. R97-R104 ◽  
Author(s):  
Iban Seiliez ◽  
Nathalie Sabin ◽  
Jean-Charles Gabillard
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Growth Factor ◽  
Nuclear Translocation ◽  
Protein Activity ◽  
Gh Treatment ◽  
Its Gene ◽  
Igf I ◽  
The Relationship

In mammals, much evidence has demonstrated the important role of myostatin (MSTN) in regulating muscle mass and identified the transcription factor forkhead box O (FoxO) 1 as a key regulator of its gene expression during atrophy. However, in trout, food deprivation leads to muscle atrophy without an increase of the expression of mstn genes in the muscle. We therefore studied the relationship between FoxO1 activity and the expression of both mstn genes ( mstn1a and mstn1b) in primary culture of trout myotubes. To this aim, two complementary studies were undertaken. In the former, FoxO1 protein activity was modified with insulin-like growth factor-I (IGF-I) treatment, and the consequences on the expression of both mstn genes were monitored. In the second experiment, the expression of both studied genes was modified with growth hormone (GH) treatment, and the activation of FoxO1 protein was investigated. We found that IGF-I induced the phosphorylation of FoxO1 and FoxO4. Moreover, under IGF-I stimulation, FoxO1 was no longer localized in the nucleus, indicating that this growth factor inhibited FoxO1 activity. However, IGF-I treatment had no effect on mstn1a and mstn1b expression, suggesting that FoxO1 would not regulate the expression of mstn genes in trout myotubes. Furthermore, the treatment of myotubes with GH decreased the expression of both mstn genes but has no effect on the phosphorylation of FoxO1, FoxO3, and FoxO4 nor on the nuclear translocation of FoxO1. Altogether, our results showed that mstn1a and mstn1b expressions were not associated with FoxO activity, indicating that FoxO1 is likely not a key regulator of mstn genes in trout myotubes.

scholarly journals A simplified strategy for titrating gene expression reveals new relationships between genotype, environment, and bacterial growth

2020 ◽  
Author(s):  
Andrew D Mathis ◽  
Ryan M Otto ◽  
Kimberly A Reynolds
Keyword(s):  
Gene Expression ◽  
Growth Rate ◽  
Cell Phenotype ◽  
Molecular Barcoding ◽  
Guide Rnas ◽  
Gene By Environment Interactions ◽  
Rate Effects ◽  
Environmental Variations ◽  
Mutation Strategies ◽  
The Relationship

Abstract A lack of high-throughput techniques for making titrated, gene-specific changes in expression limits our understanding of the relationship between gene expression and cell phenotype. Here, we present a generalizable approach for quantifying growth rate as a function of titrated changes in gene expression level. The approach works by performing CRISPRi with a series of mutated single guide RNAs (sgRNAs) that modulate gene expression. To evaluate sgRNA mutation strategies, we constructed a library of 5927 sgRNAs targeting 88 genes in Escherichia coli MG1655 and measured the effects on growth rate. We found that a compounding mutational strategy, through which mutations are incrementally added to the sgRNA, presented a straightforward way to generate a monotonic and gradated relationship between mutation number and growth rate effect. We also implemented molecular barcoding to detect and correct for mutations that ‘escape’ the CRISPRi targeting machinery; this strategy unmasked deleterious growth rate effects obscured by the standard approach of ignoring escapers. Finally, we performed controlled environmental variations and observed that many gene-by-environment interactions go completely undetected at the limit of maximum knockdown, but instead manifest at intermediate expression perturbation strengths. Overall, our work provides an experimental platform for quantifying the phenotypic response to gene expression variation.

scholarly journals CNBP controls IL-12 gene transcription and Th1 immunity

2018 ◽  
Vol 215 (12) ◽  
pp. 3136-3150 ◽  
Author(s):  
Yongzhi Chen ◽  
Shruti Sharma ◽  
Patricia A. Assis ◽  
Zhaozhao Jiang ◽  
Roland Elling ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gene Transcription ◽  
Nuclear Translocation ◽  
Gene Signature ◽  
Binding Activity ◽  
Microbial Pathogens ◽  
Cytokine Gene Expression ◽  
Nucleic Acid Binding ◽  
Th1 Cell ◽  
Dna Binding Activity

An inducible program of inflammatory gene expression is a hallmark of antimicrobial defenses. Recently, cellular nucleic acid–binding protein (CNBP) was identified as a regulator of nuclear factor-kappaB (NF-κB)–dependent proinflammatory cytokine gene expression. Here, we generated mice lacking CNBP and found that CNBP regulates a very restricted gene signature that includes IL-12β. CNBP resides in the cytosol of macrophages and translocates to the nucleus in response to diverse microbial pathogens and pathogen-derived products. Cnbp-deficient macrophages induced canonical NF-κB/Rel signaling normally but were impaired in their ability to control the activation of c-Rel, a key driver of IL-12β gene transcription. The nuclear translocation and DNA-binding activity of c-Rel required CNBP. Lastly, Cnbp-deficient mice were more susceptible to acute toxoplasmosis associated with reduced production of IL-12β, as well as a reduced T helper type 1 (Th1) cell IFN-γ response essential to controlling parasite replication. Collectively, these findings identify CNBP as important regulator of c-Rel–dependent IL-12β gene transcription and Th1 immunity.

scholarly journals Endolysosomal Cation Channels and MITF in Melanocytes and Melanoma

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1021
Author(s):  
Carla Abrahamian ◽  
Christian Grimm
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Transcription Factor ◽  
Convincing Evidence ◽  
Signaling Cascades ◽  
Cation Channels ◽  
Pore Channel ◽  
Different Types ◽  
Canonical Wnt ◽  
The Relationship

Microphthalmia-associated transcription factor (MITF) is the principal transcription factor regulating pivotal processes in melanoma cell development, growth, survival, proliferation, differentiation and invasion. In recent years, convincing evidence has been provided attesting key roles of endolysosomal cation channels, specifically TPCs and TRPMLs, in cancer, including breast cancer, glioblastoma, bladder cancer, hepatocellular carcinoma and melanoma. In this review, we provide a gene expression profile of these channels in different types of cancers and decipher their roles, in particular the roles of two-pore channel 2 (TPC2) and TRPML1 in melanocytes and melanoma. We specifically discuss the signaling cascades regulating MITF and the relationship between endolysosomal cation channels, MAPK, canonical Wnt/GSK3 pathways and MITF.

scholarly journals Protein citrullination as a source of cancer neoantigens

2021 ◽  
Vol 9 (6) ◽  
pp. e002549
Author(s):  
Hiroyuki Katayama ◽  
Makoto Kobayashi ◽  
Ehsan Irajizad ◽  
Alejandro Sevillarno ◽  
Nikul Patel ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Immune Response ◽  
Protein Expression ◽  
Cell Lines ◽  
Cancer Cell ◽  
Family Members ◽  
Immunohistochemical Analysis ◽  
Cancer Cell Lines ◽  
Mhc Ii

BackgroundCitrulline post-translational modification of proteins is mediated by protein arginine deiminase (PADI) family members and has been associated with autoimmune diseases. The role of PADI-citrullinome in immune response in cancer has not been evaluated. We hypothesized that PADI-mediated citrullinome is a source of neoantigens in cancer that induces immune response.MethodsProtein expression of PADI family members was evaluated in 196 cancer cell lines by means of indepth proteomic profiling. Gene expression was assessed using messenger RNA data sets from The Cancer Genome Atlas. Immunohistochemical analysis of PADI2 and peptidyl-citrulline was performed using breast cancer tissue sections. Citrullinated 12–34-mer peptides in the putative Major Histocompatibility Complex-II (MHC-II) binding range were profiled in breast cancer cell lines to investigate the relationship between protein citrullination and antigen presentation. We further evaluated immunoglobulin-bound citrullinome by mass spectrometry using 156 patients with breast cancer and 113 cancer-free controls.ResultsProteomic and gene expression analyses revealed PADI2 to be highly expressed in several cancer types including breast cancer. Immunohistochemical analysis of 422 breast tumor tissues revealed increased expression of PADI2 in ER− tumors (p<0.0001); PADI2 protein expression was positively correlated (p<0.0001) with peptidyl-citrulline staining. PADI2 expression exhibited strong positive correlations with a B cell immune signature and with MHC-II-bound citrullinated peptides. Increased circulating citrullinated antigen–antibody complexes occurred among newly diagnosed breast cancer cases relative to controls (p=0.0012).ConclusionsAn immune response associated with citrullinome is a rich source of neoantigens in breast cancer with a potential for diagnostic and therapeutic applications.

scholarly journals BMI-1 Expression Heterogeneity in Endometriosis-Related and Non-Endometriotic Ovarian Carcinoma

2021 ◽  
Vol 22 (11) ◽  
pp. 6082
Author(s):  
Ludmila Lozneanu ◽  
Raluca Anca Balan ◽  
Ioana Păvăleanu ◽  
Simona Eliza Giuşcă ◽  
Irina-Draga Căruntu ◽  
...  
Keyword(s):  
Stem Cells ◽  
Statistical Analysis ◽  
Ovarian Carcinoma ◽  
Clinicopathological Characteristics ◽  
Cell Phenotype ◽  
Epithelial Tumor ◽  
Normal Organ ◽  
Ovarian Carcinogenesis ◽  
Cellular Signaling Pathway ◽  
The Relationship

BMI-1 is a key component of stem cells, which are essential for normal organ development and cell phenotype maintenance. BMI-1 expression is deregulated in cancer, resulting in the alteration of chromatin and gene transcription repression. The cellular signaling pathway that governs BMI-1 action in the ovarian carcinogenesis sequences is incompletely deciphered. In this study, we set out to analyze the immunohistochemical (IHC) BMI-1 expression in two different groups: endometriosis-related ovarian carcinoma (EOC) and non-endometriotic ovarian carcinoma (NEOC), aiming to identify the differences in its tissue profile. Methods: BMI-1 IHC expression has been individually quantified in epithelial and in stromal components by using adapted scores systems. Statistical analysis was performed to analyze the relationship between BMI-1 epithelial and stromal profile in each group and between groups and its correlation with classical clinicopathological characteristics. Results: BMI-1 expression in epithelial tumor cells was mostly low or negative in the EOC group, and predominantly positive in the NEOC group. Moreover, the stromal BMI-1 expression was variable in the EOC group, whereas in the NEOC group, stromal BMI-1 expression was mainly strong. We noted statistically significant differences between the epithelial and stromal BMI-1 profiles in each group and between the two ovarian carcinoma (OC) groups. Conclusions: Our study provides solid evidence for a different BMI-1 expression in EOC and NEOC, corresponding to the differences in their etiopathogeny. The reported differences in the BMI-1 expression of EOC and NEOC need to be further validated in a larger and homogenous cohort of study.

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