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Specialty: Microbiology
Source: Cellular Microbiology

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Total 25 results found since Jan 2013.

A novel kinase function of a nucleoside ‐diphosphate‐kinase homologue in Porphyromonas gingivalis is critical in subversion of host cell apoptosis by targeting heat‐shock protein 27
In this study, we describe a novel kinase function for bacterial effector, P. gingivalis‐Ndk, in abrogating epithelial cell death by phosphorylating heat‐shock protein 27 (HSP27) in GECs. Infection by P. gingivalis was recently suggested to increase phosphorylation of HSP27 in cancer‐epithelial cells; however, the mechanism and biological significance of antiapoptotic phospho‐HSP27 during infection has never been characterised. Interestingly, using glutathione S‐transferase‐rNdk pull‐down analysed by mass spectrometry, we identified HSP27 in GECs as a strong binder of P. gingivalis‐Ndk and further verifi...
Source: Cellular Microbiology - February 7, 2018 Category: Microbiology Authors: Jungnam Lee, JoAnn S. Roberts, Kalina R. Atanasova, Nityananda Chowdhury, Özlem Yilmaz Tags: RESEARCH ARTICLE Source Type: research

A Novel Kinase Function of a Nucleoside ‐diphosphate‐kinase Homolog in P. gingivalis is Critical in Subversion of Host Cell Apoptosis by Targeting Heat‐Shock Protein 27
In this study, we describe a novel kinase function for bacterial effector, P. gingivalis‐Ndk, in abrogating epithelial cell death by phosphorylating Heat‐shock‐protein‐27 (HSP27) in GECs. Infection by P. gingivalis was recently suggested to increase phosphorylation of HSP27 in cancer‐epithelial cells; however, the mechanism and biological significance of anti‐apoptotic phospho‐HSP27 during infection has never been characterized. Interestingly, using GST‐rNdk Pull‐down analyzed by mass‐spectrometry, we identified HSP27 in GECs as a strong binder of P. gingivalis‐Ndk and further verified using confocal ...
Source: Cellular Microbiology - January 23, 2018 Category: Microbiology Authors: Jungnam Lee, JoAnn S. Roberts, Kalina R. Atanasova, Nityananda Chowdhury, Özlem Yilmaz Tags: RESEARCH ARTICLE Source Type: research

Identification of GBF1 as a cellular factor required for Hepatitis E virus RNA replication
Abstract The hepatitis E virus (HEV) genome is a single‐stranded, positive‐sense RNA that encodes three proteins including the ORF1 replicase. Mechanisms of HEV replication in host cells are unclear and only a few cellular factors involved in this step have been identified so far. Here, we used brefeldin A (BFA) that blocks the activity of the cellular Arf guanine nucleotide exchange factors GBF1, BIG1 and BIG2, which play a major role in reshuffling of cellular membranes. We showed that BFA inhibits HEV replication in a dose‐dependent manner. The use of siRNA and Golgicide A identified GBF1 as a host factor critical...
Source: Cellular Microbiology - November 7, 2017 Category: Microbiology Authors: Rayan Farhat, Maliki Ankavay, Nadjet Lebsir, J érôme Gouttenoire, Catherine L. Jackson, Czeslaw Wychowski, Darius Moradpour, Jean Dubuisson, Yves Rouille, Laurence Cocquerel Tags: RESEARCH ARTICLE Source Type: research

Orientia tsutsugamushi Ank9 is a multifunctional effector that utilizes a novel GRIP ‐like Golgi localization domain for Golgi‐to‐endoplasmic reticulum trafficking and interacts with host COPB2
This report identifies a novel microbial GLD, links Ank9 to the ability of O. tsutsugamushi to perturb Golgi structure, and describes the first mechanism by which any Orientia effector targets the secretory pathway.
Source: Cellular Microbiology - January 20, 2017 Category: Microbiology Authors: Andrea R. Beyer, Kyle G. Rodino, Lauren VieBrock, Ryan S. Green, Brittney K. Tegels, Lee D. Oliver, Richard T. Marconi, Jason A. Carlyon Tags: RESEARCH ARTICLE Source Type: research

SNARE proteins required during Trypanosoma cruzi parasitophorous vacuole development
Abstract Trypanosoma cruzi, the etiologic agent of Chagas disease, is an obligate intracellular parasite that exploits different host vesicular pathways to invade the target cells. Vesicular and target SNAREs are key proteins of the intracellular membrane fusion machinery. During the early times of T. cruzi infection, several vesicles are attracted to the parasite contact sites in the plasma membrane. Fusion of these vesicles promotes the formation of the parasitic vacuole and parasite entry. In this work, we study the requirement and the nature of SNAREs involved in the fusion events which take place during T. cruzi infec...
Source: Cellular Microbiology - November 30, 2016 Category: Microbiology Authors: Juan Agust ín Cueto, María Cristina Vanrell, Betiana Nebaí Salassa, Sébastien Nola, Thierry Galli, María Isabel Colombo, Patricia Silvia Romano Tags: RESEARCH ARTICLE Source Type: research

Aggregatibacter actinomycetemcomitans outer membrane protein 29 (Omp29) induces TGF ‐β‐regulated apoptosis signal in human gingival epithelial cells via fibronectin/integrinβ1/FAK cascade
Summary Gingival junctional epithelial cell apoptosis caused by periodontopathic bacteria exacerbates periodontitis. This pathological apoptosis is involved in the activation of transforming growth factor β (TGF‐β). However, the molecular mechanisms by which microbes induce the activation of TGF‐β remain unclear. We previously reported that Aggregatibacter actinomycetemcomitans (Aa) activated TGF‐β receptor (TGF‐βR)/smad2 signalling to induce epithelial cell apoptosis, even though Aa cannot bind to TGF‐βR. Additionally, outer membrane protein 29 kDa (Omp29), a member of the Aa Omps family, can induce acti...
Source: Cellular Microbiology - June 9, 2016 Category: Microbiology Authors: Tetsuya Yoshimoto, Tsuyoshi Fujita, Mikihito Kajiya, Kazuhisa Ouhara, Shinji Matsuda, Hitoshi Komatsuzawa, Hideki Shiba, Hidemi Kurihara Tags: Research Article Source Type: research

Moraxella catarrhalis induces CEACAM3 ‐Syk‐CARD9‐dependent activation of human granulocytes
Summary The human restricted pathogen Moraxella catarrhalis is an important causal agent for exacerbations in chronic obstructive lung disease in adults. In such patients, increased numbers of granulocytes are present in the airways, which correlate with bacteria‐induced exacerbations and severity of the disease. Our study investigated whether the interaction of M. catarrhalis with the human granulocyte‐specific carcinoembryonic antigen‐related cell adhesion molecule (CEACAM)‐3 is linked to NF‐κB activation, resulting in chemokine production. Granulocytes from healthy donors and NB4 cells were infected with M....
Source: Cellular Microbiology - May 2, 2016 Category: Microbiology Authors: A. Heinrich, K.  A. Heyl, E. Klaile, M. M. Müller, T. E. Klassert, A. Wiessner, K. Fischer, R. R. Schumann, U. Seifert, K. Riesbeck, A. Moter, B. B. Singer, S. Bachmann, H. Slevogt Tags: Research Article Source Type: research

Aggregatibacter actinomycetemcomitans outer membrane protein 29 (Omp29) induces TGF‐β‐regulated apoptosis signal in human gingival epithelial cells via fibronectin/integrinβ1/FAK cascade.
Abstract Gingival junctional epithelial cell apoptosis caused by periodontopathic bacteria exacerbates periodontitis. This pathological apoptosis is involved in the activation of transforming growth factor β (TGF‐β). However, the molecular mechanisms by which microbes induce the activation of TGF‐β remain unclear. We previously reported that Aggregatibacter actinomycetemcomitans (Aa) activated TGF‐β receptor (TGF‐βR)/smad2 signaling to induce epithelial cell apoptosis, even though Aa cannot bind to TGF‐βR. Additionally, outer membrane protein 29 kDa (Omp29), a member of the Aa Omps family, can induce acti...
Source: Cellular Microbiology - April 28, 2016 Category: Microbiology Authors: Tetsuya Yoshimoto, Tsuyoshi Fujita, Mikihito Kajiya, Kazuhisa Ouhara, Shinji Matsuda, Hitoshi Komatsuzawa, Hideki Shiba, Hidemi Kurihara Tags: Research article Source Type: research

Moraxella catarrhalis induces CEACAM3‐Syk‐Card9‐dependent activation of human granulocytes
Summary The human restricted pathogen Moraxella catarrhalis is an important causal agent for exacerbations in chronic obstructive lung disease (COPD) in adults. In such patients, increased numbers of granulocytes are present in the airways, which correlate with bacteria‐induced exacerbations and severity of the disease. Our study investigated whether the interaction of M. catarrhalis with the human granulocyte‐specific carcinoembryonic antigen‐related cell adhesion molecule (CEACAM)‐3 is linked to NF‐κB activation, resulting in chemokine production. Granulocytes from healthy donors and NB4 cells were infected wi...
Source: Cellular Microbiology - March 31, 2016 Category: Microbiology Authors: A Heinrich, KA Heyl, E Klaile, MM Müller, TE Klassert, A Wiessner, K Fischer, RR Schumann, U Seifert, K Riesbeck, A Moter, BB Singer, S Bachmann, H Slevogt Tags: Research article Source Type: research

Subtilase cytotoxin produced by locus of enterocyte effacement ‐negative Shiga‐toxigenic Escherichia coli induces stress granule formation
Summary Subtilase cytotoxin (SubAB) is mainly produced by locus of enterocyte effacement (LEE)‐negative strains of Shiga‐toxigenic Escherichia coli (STEC). SubAB cleaves an endoplasmic reticulum (ER) chaperone, BiP/Grp78, leading to induction of ER stress. This stress causes activation of ER stress sensor proteins and induction of caspase‐dependent apoptosis. We found that SubAB induces stress granules (SG) in various cells. Aim of this study was to explore the mechanism by which SubAB induced SG formation. Here, we show that SubAB‐induced SG formation is regulated by activation of double‐stranded RNA‐activated...
Source: Cellular Microbiology - February 20, 2016 Category: Microbiology Authors: Hiroyasu Tsutsuki, Kinnosuke Yahiro, Kohei Ogura, Kimitoshi Ichimura, Sunao Iyoda, Makoto Ohnishi, Sayaka Nagasawa, Kazuko Seto, Joel Moss, Masatoshi Noda Tags: Original article Source Type: research

Subtilase cytotoxin produced by locus of enterocyte effacement‐negative shiga‐toxigenic Escherichia coli induces stress granule formation
This article is protected by copyright. All rights reserved.
Source: Cellular Microbiology - January 9, 2016 Category: Microbiology Authors: Hiroyasu Tsutsuki, Kinnosuke Yahiro, Kohei Ogura, Kimitoshi Ichimura, Sunao Iyoda, Makoto Ohnishi, Sayaka Nagasawa, Kazuko Seto, Joel Moss, Masatoshi Noda Tags: Research article Source Type: research

Porphyromonas gingivalis initiates a mesenchymal‐like transition through ZEB1 in gingival epithelial cells
This article is protected by copyright. All rights reserved.
Source: Cellular Microbiology - December 7, 2015 Category: Microbiology Authors: Maryta N. Sztukowska, Akintunde Ojo, Saira Ahmed, Anne L. Carenbauer, Qian Wang, Brain Shumway, Howard F. Jenkinson, Huizhi Wang, Douglas S. Darling, Richard J. Lamont Tags: Research article Source Type: research

cAMP signaling of Bordetella adenylate cyclase toxin through the SHP‐1 phosphatase activates the BimEL‐Bax pro‐apoptotic cascade in phagocytes
Summary The adenylate cyclase toxin‐hemolysin (CyaA, ACT or AC‐Hly) plays a key role in virulence of Bordetella pertussis. CyaA penetrates myeloid cells expressing the complement receptor 3 (αMβ2 integrin CD11b/CD18) and subverts bactericidal capacities of neutrophils and macrophages by catalyzing unregulated conversion of cytosolic ATP to the key signaling molecule cAMP. We show that the signaling of CyaA‐produced cAMP hijacks, by an as yet unknown mechanism, the activity of the tyrosine phosphatase SHP‐1 and activates the pro‐apoptotic BimEL‐Bax cascade. Mitochondrial hyperpolarization occurred in human THP...
Source: Cellular Microbiology - September 1, 2015 Category: Microbiology Authors: Jawid Nazir Ahmad, Ondrej Cerny, Irena Linhartova, Jiri Masin, Radim Osicka, Peter Sebo Tags: Research article Source Type: research

Antibacterial effect of mesenchymal stem cells against Escherichia coli is mediated by secretion of beta‐defensin‐2 via toll like receptor 4 signaling
This study was done to elucidate the mechanism underlying the antibacterial effects of MSCs. The growth of E. coli in vitro was significantly inhibited only by MSCs or their conditioned medium with bacterial preconditioning, but not by fibroblasts or their conditioned medium. Microarray analysis identified significant up‐regulation of toll like receptors (TLR)‐2 and TLR‐4, and β‐defensin 2 (BD2) in MSCs compared with fibroblasts after E. coli exposure. The increased BD2 level and the in vitro antibacterial effects of MSCs were abolished by specific antagonist or by siRNA‐mediated knockdown of TLR‐4, but not TL...
Source: Cellular Microbiology - September 1, 2015 Category: Microbiology Authors: Dong Kyung Sung, Yun Sil Chang, Se In Sung, Hye Soo Yoo, So Yoon Ahn, Won Soon Park Tags: Research article Source Type: research

FOXO responses to Porphyromonas gingivalis in epithelial cells
In this study we show that P. gingivalis infection induces the dephosphorylation and activation of FOXO1, 3, and 4 in gingival epithelial cells. In addition, immunofluorescence showed that FOXO1 accumulated in the nucleus of P. gingivalis‐infected cells. Quantitative RT‐PCR (qRT‐PCR) demonstrated that transcription of genes involved in protection against oxidative stress (Cat, Sod2, Prdx3), inflammatory responses (IL1β), and anti‐apoptosis (Bcl‐6) was induced by P. gingivalis, and siRNA‐mediated knockdown of FOXO1 suppressed the transcriptional activation of these genes. P. gingivalis‐induced secretion of IL...
Source: Cellular Microbiology - May 1, 2015 Category: Microbiology Authors: Qian Wang, Maryta Sztukowska, Akintunde Ojo, David A. Scott, Huizhi Wang, Richard J. Lamont Tags: Research Article Source Type: research