Turn-ons and Turn-offs

Rosenthal, Ken S.; Anand, Malini; Donley, Chad

doi:10.1097/ipc.0b013e31816fd5f0

Cited by 4 publications

(1 citation statement)

References 16 publications

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“…In most bacterial pathogens, virulence factors are tightly regulated [15]. One such regulator is the ferric uptake regulator (Fur) which is sensitive to the oxidative-stress response [16].…”

Section: Introductionmentioning

confidence: 99%

Protein expression and transcription profiles of three strains of Aeromonas salmonicida ssp. salmonicida under normal and iron-limited culture conditions

et al. 2014

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BackgroundAeromonas salmonicida is an important fish pathogen that produces a wide and varied array of virulence factors. Here we used iron deprivation by addition of the chelator 2’2-dipyridyl to induce the expression of several such virulence factors in three isolates of Aeromonas salmonicida (one avirulent and two virulent). By using SDS-PAGE followed by mass spectrometry, we identified proteins that appeared differentially expressed under these conditions. The differential transcription of the identified gene products were subsequently measured by reverse transcription quantitative real-time PCR (RT-qPCR).ResultsOur initial screening using SDS-PAGE identified five proteins that appeared differentially expressed in virulent and avirulent isolates or, within the same isolates, between bacteria cultivated under iron-rich or iron-deprived conditions. The transcription of the genes coding for these proteins were subsequently quantified by RT-qPCR. Results of this analysis demonstrated that the gene coding for alkyl hydroperoxide reductase (AhpC), a protein involved in oxidative stress response, was transcribed at a higher rate in the virulent strain as compared to the avirulent strain. Additionally, it was observed that addition of an iron chelator to the culture medium lead to a reduction of the transcription levels of the regulatory histone-like nucleoid structuring protein (H-NS). This was consistent in all three isolates. On the other hand, the transcription levels of the virulence array protein (VapA) and the protein ATP-synthetase F (ATPF) displayed only limited changes, despite being the dominant component of a protein fraction that displayed changes during the preliminary SDS-PAGE screening. This was true regardless of the culture conditions and of the isolates considered. Finally, transcription of the enzyme enolase was upregulated in the iron-deprived broths in all isolates.ConclusionsWe identified several genes differentially expressed under culture conditions known to lead to the overexpression of virulence factors. In addition, we identified alkyl hydroperoxide as being overexpressed in the virulent isolates compared to the avirulent isolates. The results from this study will contribute to enhance our understanding of the virulence of A. salmonicida and may suggest new directions for further research.

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Section: Introductionmentioning

confidence: 99%

Protein expression and transcription profiles of three strains of Aeromonas salmonicida ssp. salmonicida under normal and iron-limited culture conditions

et al. 2014

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Phenotypic and Genotypic Analyses of Methicillin-Resistant Staphylococcus aureus Isolates from a Community Hospital

Tran¹,

Stein²,

Common³

et al. 2009

Infectious Diseases in Clinical Practice

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Role of Glycogen Synthase Kinase-3 in Cell Fate and Epithelial-Mesenchymal Transitions

Doble

Woodgett²

2007

Cells Tissues Organs

165

129

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Epithelial cells usually exist as sheets of immotile, tightly packed, well-coupled, polarized cells with distinct apical, basal and lateral surfaces. Remarkably, these cells can dramatically alter their morphology to become motile, fibroblast-like mesenchymal cells in a process of epithelial-mesenchymal transition (EMT). This process and the reverse, mesenchymal-epithelial transition, occur repeatedly during normal embryonic development. A phenomenon similar to physiological EMT occurs during the pathophysiological progression of some cancers. Tumours of epithelial origin, as they transform to malignancy, appear to exploit the innate plasticity of epithelial cells, with EMT conferring increased invasiveness and metastatic potential. Key to the maintenance of epithelial cell identity is the expression of E-cadherin, a protein that is required for tight intercellular adhesion along the lateral surfaces of adjacent epithelial cells. Loss of functional E-cadherin is a critical event in EMT. An important regulator of E-cadherin expression is the protein Snail, a zinc-finger transcriptional repressor. Snail contains several consensus sites for the kinase, glycogen synthase kinase-3 (GSK-3), and accumulating evidence indicates that it is a GSK-3 substrate. Phosphorylation of Snail by GSK-3 facilitates its proteasomal degradation. Conversely, inhibition of GSK-3 leads to Snail accumulation, E-cadherin downregulation, and development of EMT in cultured epithelial cells. Several signalling pathways implicated in the progression of EMT, including the Wnt and phosphoinositide 3-kinase pathways, use GSK-3 to mediate their responses. In these pathways, GSK-3’s regulation of other transcriptional effectors like β-catenin works in concert with changes in Snail to orchestrate the EMT process. This review focuses on the emerging role of GSK-3 as a modulator of cell fate and EMT in the contexts of development, in vitro cell culture and cancer.

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Turn-ons and Turn-offs

Cited by 4 publications

References 16 publications

Protein expression and transcription profiles of three strains of Aeromonas salmonicida ssp. salmonicida under normal and iron-limited culture conditions

Protein expression and transcription profiles of three strains of Aeromonas salmonicida ssp. salmonicida under normal and iron-limited culture conditions

Phenotypic and Genotypic Analyses of Methicillin-Resistant Staphylococcus aureus Isolates from a Community Hospital

Role of Glycogen Synthase Kinase-3 in Cell Fate and Epithelial-Mesenchymal Transitions

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