scholarly journals Acidic extracellular pH of tumors induces octamer-binding transcription factor 4 expression in murine fibroblasts in vitro and in vivo

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Avik Som ◽  
Sharon Bloch ◽  
Joseph E. Ippolito ◽  
Samuel Achilefu
Keyword(s):  
Transcription Factor ◽  
Extracellular Ph ◽  
Murine Fibroblasts ◽  
Acidic Extracellular Ph ◽  
Octamer Binding Transcription Factor ◽  
Transcription Factor 4

scholarly journals Molecular and Cellular Function of Transcription Factor 4 in Pitt-Hopkins Syndrome

2021 ◽  
pp. 1-9
Author(s):  
Huei-Ying Chen ◽  
Joseph F. Bohlen ◽  
Brady J. Maher
Keyword(s):  
Transcription Factor ◽  
Regulatory Networks ◽  
Autosomal Dominant ◽  
Autism Spectrum ◽  
Therapeutic Interventions ◽  
Type I ◽  
Helix Loop Helix ◽  
Transcription Factor 4

Transcription factor 4 (TCF4, also known as ITF2 or E2-2) is a type I basic helix-loop-helix transcription factor. Autosomal dominant mutations in TCF4 cause Pitt-Hopkins syndrome (PTHS), a rare syndromic form of autism spectrum disorder. In this review, we provide an update on the progress regarding our understanding of TCF4 function at the molecular, cellular, physiological, and behavioral levels with a focus on phenotypes and therapeutic interventions. We examine upstream and downstream regulatory networks associated with TCF4 and discuss a range of in vitro and in vivo data with the aim of understanding emerging TCF4-specific mechanisms relevant for disease pathophysiology. In conclusion, we provide comments about exciting future avenues of research that may provide insights into potential new therapeutic targets for PTHS.

scholarly journals Identification of Effectors of Synergistic Lethality in Candida albicans-Staphylococcus aureus Polymicrobial Intra-abdominal Infection

2021 ◽  
Author(s):  
◽  
Olivia Todd ◽  
Keyword(s):  
Staphylococcus Aureus ◽  
Transcription Factor ◽  
Candida Albicans ◽  
Candida Species ◽  
Toxin Production ◽  
Extracellular Ph ◽  
Abdominal Infection ◽  
Intra Abdominal Infection

Candida albicans, an opportunistic fungal pathogen, and Staphylococcus aureus, a ubiquitous pathogenic bacterium, are among the most prevalent causes of nosocomial infections and cause severe morbidity and mortality. Moreover, they are frequently coisolated from central venous catheters and deep-seated infections, including intra-abdominal sepsis. Relatively little is known about the complex interactions and signaling events that occur between microbes and even less so how microbial “cross-talk” shapes human health and disease. Using a murine model of polymicrobial intra-abdominal infection (IAI), we have previously shown that coinfection with C. albicans and S. aureus leads to synergistic lethality whereas monomicrobial infection is nonlethal. Therefore, we aimed to identify staphylococcal virulence determinants that drive lethal synergism in polymicrobial IAI. Using the toxigenic S. aureus strain JE2, we observed that co-infection with C. albicans led to a striking 80-100% mortality rate within 20 h p.i while monomicrobial infections were non-lethal. Use of a GFP-P3 promoter S. aureus reporter strain revealed enhanced activation of the staphylococcal agr quorum sensing system during in vitro polymicrobial versus monomicrobial growth. Analyses by qPCR, Western blot, and toxin functional assays confirmed enhanced agr-associated gene transcription and increases in secreted α- and δ-toxins. C. albicans-mediated elevated toxin production and hemolytic activity was determined to be agrA-dependent and genetic knockout and complementation of hla identified ⍺-toxin as the key staphylococcal virulence factor driving lethal synergism. Analysis of mono- and polymicrobial infection 8 h p.i. demonstrated equivalent bacterial burden in the peritoneal cavity, but significantly elevated levels of α-toxin (3-fold) and the eicosanoid PGE2 (4-fold) during co-infection. Importantly, prophylactic passive vaccination using the monoclonal anti-⍺-toxin antibody MEDI4893* led to significantly improved survival rates as compared to treatment with isotype control antibody. Collectively, these results define α-toxin as an essential virulence determinant during C. albicans-S. aureus IAI and describe a novel mechanism by which a human pathogenic fungus can augment the virulence of a highly pathogenic bacterium in vivo. We next sought to unravel the mechanism by which C. albicans drives enhanced staphylococcal ⍺-toxin production. Using a combination of functional and genetic approaches, we determined that an intact agr quorum sensing regulon is necessary for enhanced ⍺-toxin production during coculture and that a secreted candidal factor likely is not implicated in elevating agr activation. As the agr system is pH sensitive, we observed that C. albicans raises the pH during polymicrobial growth and that this correlates with increased agr activity and ⍺-toxin production. By using a C. albicans mutant deficient in alkalinization (stp2Δ/Δ), we confirmed that modulation of the extracellular pH by C. albicans can drive agr expression and toxin production. Additionally, the use of various Candida species (C. glabrata, C. dubliniensis, C. tropicalis, C. parapsilosis, and C. krusei) demonstrated that those capable of raising the extracellular pH correlated with elevated agr activity and ⍺-toxin production during coculture. Overall, we demonstrated that alkalinization of the extracellular pH by the Candida species leads to sustained activation of the staphylococcal agr system. Finally, we correlated ⍺-toxin production with significant increases in biomarkers of liver and kidney damage during coinfection and determined that functional toxin was required for morbidity and mortality. We next sought to determine the candidal effector(s) mediating this enhanced virulence by employing an unbiased screening approach. C. albicans transcription factor mutants were evaluated for their ability to induce S. aureus agr activation in polymicrobial culture. Incredibly, we identified several mutants that displayed defects in augmenting S. aureus agr activity in vitro. Two of the mutants failed to completely synergize with S. aureus in vivo and further analysis revealed the necessity of the uncharacterized C. albicans transcription factor, ZCF13, in driving enhanced toxin production both in vitro and in vivo. Collectively, we identified a novel effector by which C. albicans augments S. aureus virulence and identified a potential mechanism of fungal-bacterial lethal synergism.

Subnuclear compartmentalization of sequence-specific transcription factors and regulation of eukaryotic gene expression

2005 ◽  
Vol 83 (4) ◽  
pp. 535-547 ◽  
Author(s):  
Gareth N Corry ◽  
D Alan Underhill
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activation ◽  
Current Knowledge ◽  
Nuclear Architecture ◽  
Subnuclear Localization ◽  
Modular Structures

To date, the majority of the research regarding eukaryotic transcription factors has focused on characterizing their function primarily through in vitro methods. These studies have revealed that transcription factors are essentially modular structures, containing separate regions that participate in such activities as DNA binding, protein–protein interaction, and transcriptional activation or repression. To fully comprehend the behavior of a given transcription factor, however, these domains must be analyzed in the context of the entire protein, and in certain cases the context of a multiprotein complex. Furthermore, it must be appreciated that transcription factors function in the nucleus, where they must contend with a variety of factors, including the nuclear architecture, chromatin domains, chromosome territories, and cell-cycle-associated processes. Recent examinations of transcription factors in the nucleus have clarified the behavior of these proteins in vivo and have increased our understanding of how gene expression is regulated in eukaryotes. Here, we review the current knowledge regarding sequence-specific transcription factor compartmentalization within the nucleus and discuss its impact on the regulation of such processes as activation or repression of gene expression and interaction with coregulatory factors.Key words: transcription, subnuclear localization, chromatin, gene expression, nuclear architecture.

scholarly journals Integrin α3β1 Promotes Invasive and Metastatic Properties of Breast Cancer Cells through Induction of the Brn-2 Transcription Factor

Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 480
Author(s):  
Rakshitha Pandulal Miskin ◽  
Janine S. A. Warren ◽  
Abibatou Ndoye ◽  
Lei Wu ◽  
John M. Lamar ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Transcription Factor ◽  
Cancer Cells ◽  
Cell Invasion ◽  
Breast Cancer Cells ◽  
Gene Promoter ◽  
Akt Inhibitor ◽  
Integrin Α3β1

In the current study, we demonstrate that integrin α3β1 promotes invasive and metastatic traits of triple-negative breast cancer (TNBC) cells through induction of the transcription factor, Brain-2 (Brn-2). We show that RNAi-mediated suppression of α3β1 in MDA-MB-231 cells caused reduced expression of Brn-2 mRNA and protein and reduced activity of the BRN2 gene promoter. In addition, RNAi-targeting of Brn-2 in MDA-MB-231 cells decreased invasion in vitro and lung colonization in vivo, and exogenous Brn-2 expression partially restored invasion to cells in which α3β1 was suppressed. α3β1 promoted phosphorylation of Akt in MDA-MB-231 cells, and treatment of these cells with a pharmacological Akt inhibitor (MK-2206) reduced both Brn-2 expression and cell invasion, indicating that α3β1-Akt signaling contributes to Brn-2 induction. Analysis of RNAseq data from patients with invasive breast carcinoma revealed that high BRN2 expression correlates with poor survival. Moreover, high BRN2 expression positively correlates with high ITGA3 expression in basal-like breast cancer, which is consistent with our experimental findings that α3β1 induces Brn-2 in TNBC cells. Together, our study demonstrates a pro-invasive/pro-metastatic role for Brn-2 in breast cancer cells and identifies a role for integrin α3β1 in regulating Brn-2 expression, thereby revealing a novel mechanism of integrin-dependent breast cancer cell invasion.

scholarly journals Thymoquinone, a Dietary Bioactive Compound, Exerts Anti-Inflammatory Effects in Colitis by Stimulating Expression of the Colonic Epithelial PPAR-γ Transcription Factor

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1343
Author(s):  
Balaji Venkataraman ◽  
Saeeda Almarzooqi ◽  
Vishnu Raj ◽  
Abdullah T. Alhassani ◽  
Ahmad S. Alhassani ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Activity Index ◽  
Nigella Sativa ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Ppar Γ ◽  
Anti Inflammatory ◽  
Ht 29

Inflammatory bowel diseases (IBD) are chronic inflammatory disorders with increasing incidence and prevalence worldwide. Here, we investigated thymoquinone (TQ), a naturally occurring phytochemical present in Nigella sativa, for anti-inflammatory effects in colonic inflammation. To address this, we used in vivo (mice) and in vitro (HT-29 cells) models in this investigation. Our results showed that TQ treatment significantly reduced the disease activity index (DAI), myeloperoxidase (MPO) activity, and protected colon microscopic architecture. In addition, TQ also reduced the expression of proinflammatory cytokines and mediators at both the mRNA and protein levels. Further, TQ decreased phosphorylation of the activated mitogen-activated protein kinase (MAPK) signaling pathway and nuclear factor kappa B (NF-κB) proteins and enhanced colon epithelial PPAR-γ transcription factor expression. TQ significantly decreased proinflammatory chemokines (CXCL-1 and IL-8), and mediator (COX-2) mRNA expression in HT-29 cells treated with TNF-α. TQ also increased HT-29 PPAR-γ mRNA, PPAR-γ protein expression, and PPAR-γ promoter activity. These results indicate that TQ inhibits MAPK and NF-κB signaling pathways and transcriptionally regulates PPAR-γ expression to induce potent anti-inflammatory activity in vivo and in vitro models of colon inflammation.

scholarly journals Progression and Differentiation of Alveolar Rhabdomyosarcoma Is Regulated by PAX7 Transcription Factor—Significance of Tumor Subclones

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1870
Author(s):  
Klaudia Skrzypek ◽  
Grażyna Adamek ◽  
Marta Kot ◽  
Bogna Badyra ◽  
Marcin Majka
Keyword(s):  
Transcription Factor ◽  
Cell Lines ◽  
Migration Activity ◽  
Id Proteins ◽  
Rh30 Cell ◽  
Str Profile ◽  
And Migration

Rhabdomyosarcoma (RMS), is the most frequent soft tissue tumor in children that originates from disturbances in differentiation process. Mechanisms leading to the development of RMS are still poorly understood. Therefore, by analysis of two RMS RH30 cell line subclones, one subclone PAX7 negative, while the second one PAX7 positive, and comparison with other RMS cell lines we aimed at identifying new mechanisms crucial for RMS progression. RH30 subclones were characterized by the same STR profile, but different morphology, rate of proliferation, migration activity and chemotactic abilities in vitro, as well as differences in tumor morphology and growth in vivo. Our analysis indicated a different level of expression of adhesion molecules (e.g., from VLA and ICAM families), myogenic microRNAs, such as miR-206 and transcription factors, such as MYOD, MYOG, SIX1, and ID. Silencing of PAX7 transcription factor with siRNA confirmed the crucial role of PAX7 transcription factor in proliferation, differentiation and migration of RMS cells. To conclude, our results suggest that tumor cell lines with the same STR profile can produce subclones that differ in many features and indicate crucial roles of PAX7 and ID proteins in the development of RMS.

scholarly journals RIP3 impedes transcription factor EB to suppress autophagic degradation in septic acute kidney injury

2021 ◽  
Vol 12 (6) ◽  
Author(s):  
Ruizhao Li ◽  
Xingchen Zhao ◽  
Shu Zhang ◽  
Wei Dong ◽  
Li Zhang ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Transcription Factor ◽  
Nuclear Translocation ◽  
Kidney Injury ◽  
Septic Acute Kidney Injury ◽  
Transcription Factor Eb ◽  
Autophagic Degradation ◽  
Lps Treatment

AbstractAutophagy is an important renal-protective mechanism in septic acute kidney injury (AKI). Receptor interacting protein kinase 3 (RIP3) has been implicated in the renal tubular injury and renal dysfunction during septic AKI. Here we investigated the role and mechanism of RIP3 on autophagy in septic AKI. We showed an activation of RIP3, accompanied by an accumulation of the autophagosome marker LC3II and the autophagic substrate p62, in the kidneys of lipopolysaccharide (LPS)-induced septic AKI mice and LPS-treated cultured renal proximal tubular epithelial cells (PTECs). The lysosome inhibitor did not further increase the levels of LCII or p62 in LPS-treated PTECs. Moreover, inhibition of RIP3 attenuated the aberrant accumulation of LC3II and p62 under LPS treatment in vivo and in vitro. By utilizing mCherry-GFP-LC3 autophagy reporter mice in vivo and PTECs overexpression mRFP-GFP-LC3 in vitro, we observed that inhibition of RIP3 restored the formation of autolysosomes and eliminated the accumulated autophagosomes under LPS treatment. These results indicated that RIP3 impaired autophagic degradation, contributing to the accumulation of autophagosomes. Mechanistically, the nuclear translocation of transcription factor EB (TFEB), a master regulator of the lysosome and autophagy pathway, was inhibited in LPS-induced mice and LPS-treated PTECs. Inhibition of RIP3 restored the nuclear translocation of TFEB in vivo and in vitro. Co-immunoprecipitation further showed an interaction of RIP3 and TFEB in LPS-treated PTECs. Also, the expression of LAMP1 and cathepsin B, two potential target genes of TFEB involved in lysosome function, were decreased under LPS treatment in vivo and in vitro, and this decrease was rescued by inhibiting RIP3. Finally, overexpression of TFEB restored the autophagic degradation in LPS-treated PTECs. Together, the present study has identified a pivotal role of RIP3 in suppressing autophagic degradation through impeding the TFEB-lysosome pathway in septic AKI, providing potential therapeutic targets for the prevention and treatment of septic AKI.

scholarly journals Arsenic Directly Binds to and Activates the Yeast AP-1-Like Transcription Factor Yap8

2015 ◽  
Vol 36 (6) ◽  
pp. 913-922 ◽  
Author(s):  
Nallani Vijay Kumar ◽  
Jianbo Yang ◽  
Jitesh K. Pillai ◽  
Swati Rawat ◽  
Carlos Solano ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Transcriptional Activation ◽  
Transcriptional Response ◽  
Transcriptional Regulator ◽  
Yeast Protein ◽  
Content Type ◽  
Arsenic Tolerance ◽  
Arsenic Sensing

The AP-1-like transcription factor Yap8 is critical for arsenic tolerance in the yeastSaccharomyces cerevisiae. However, the mechanism by which Yap8 senses the presence of arsenic and activates transcription of detoxification genes is unknown. Here we demonstrate that Yap8 directly binds to trivalent arsenite [As(III)]in vitroandin vivoand that approximately one As(III) molecule is bound per molecule of Yap8. As(III) is coordinated by three sulfur atoms in purified Yap8, and our genetic and biochemical data identify the cysteine residues that form the binding site as Cys132, Cys137, and Cys274. As(III) binding by Yap8 does not require an additional yeast protein, and Yap8 is regulated neither at the level of localization nor at the level of DNA binding. Instead, our data are consistent with a model in which a DNA-bound form of Yap8 acts directly as an As(III) sensor. Binding of As(III) to Yap8 triggers a conformational change that in turn brings about a transcriptional response. Thus, As(III) binding to Yap8 acts as a molecular switch that converts inactive Yap8 into an active transcriptional regulator. This is the first report to demonstrate how a eukaryotic protein couples arsenic sensing to transcriptional activation.

Activation of the heat shock transcription factor by hypoxia in normal and tumor cell lines in vivo and in vitro

1992 ◽  
Vol 23 (4) ◽  
pp. 891-897 ◽  
Author(s):  
Amato J. Giaccia ◽  
Elizabeth A. Auger ◽  
Albert Koong ◽  
David J. Terris ◽  
Andrew I. Minchinton ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Heat Shock ◽  
Tumor Cell ◽  
Cell Lines ◽  
Heat Shock Transcription Factor ◽  
Tumor Cell Lines
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