Rab5a Promotes Cytolethal Distending Toxin B-Induced Cytotoxicity and Inflammation

ABSTRACT The cytolethal distending toxin B subunit (CdtB) induces significant cytotoxicity and inflammation in many cell types that are involved in the pathogenesis of postinfectious irritable bowel syndrome (PI-IBS). However, the underlying mechanisms remain unclear. This study tested the potential role of Rab small GTPase 5a (Rab5a) in the process. We tested mRNA and protein expression of proinflammatory cytokines (interleukin-1β [IL-1β] and IL-6) in THP-1 macrophages by quantitative PCR (qPCR) and enzyme-linked immunosorbent assays (ELISAs), respectively. In the primary colonic epithelial cells, Cdt treatment induced a CdtB-Rab5a-cellugyrin association. Rab5a silencing, by target small hairpin RNAs (shRNAs), largely inhibited CdtB-induced cytotoxicity and apoptosis in colon epithelial cells. CRISPR/Cas9-mediated Rab5a knockout also attenuated CdtB-induced colon epithelial cell death. Conversely, forced overexpression of Rab5a intensified CdtB-induced cytotoxicity. In THP-1 human macrophages, Rab5a shRNA or knockout significantly inhibited CdtB-induced mRNA expression and production of proinflammatory cytokines (IL-1β and IL-6). Rab5a depletion inhibited activation of nuclear factor-κB (NF-κB) and Jun N-terminal protein kinase (JNK) signaling in CdtB-treated THP-1 macrophages. Rab5a appears essential for CdtB-induced cytotoxicity in colonic epithelial cells and proinflammatory responses in THP-1 macrophages.

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Activation of the nuclear factor-κb/green fluorescent protein by proinflammatory cytokines in gastric epithelial cells

Gastroenterology ◽

10.1016/s0016-5085(08)81526-0 ◽

2001 ◽

Vol 120 (5) ◽

pp. A307-A308 ◽

Cited By ~ 1

Author(s):

Kenta Yoshiura ◽

Tadahito Shimada ◽

Takahiro Mitsuhashi ◽

Kumi Takahashi ◽

Hideyuki Hiraishi ◽

...

Keyword(s):

Green Fluorescent Protein ◽

Epithelial Cells ◽

Proinflammatory Cytokines ◽

Fluorescent Protein ◽

Nuclear Factor Κb ◽

Nuclear Factor ◽

Gastric Epithelial Cells ◽

Green Fluorescent

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Clostridium difficile toxin A and proinflammatory cytokines stimulate corticotropin-releasing hormone receptor 2 (CRHR2) expression in human colonic epithelial cells

Gastroenterology ◽

10.1016/s0016-5085(03)80046-x ◽

2003 ◽

Vol 124 (4) ◽

pp. A9

Author(s):

Pauline M. Anton ◽

Amy Pan ◽

Tor Savidge ◽

Paul Newman ◽

Simos Simeonidis ◽

...

Keyword(s):

Clostridium Difficile ◽

Epithelial Cells ◽

Proinflammatory Cytokines ◽

Hormone Receptor ◽

Corticotropin Releasing Hormone ◽

Toxin A ◽

Colonic Epithelial Cells ◽

Releasing Hormone ◽

Clostridium Difficile Toxin ◽

Clostridium Difficile Toxin A

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PI3K is critical for the nuclear translocation of IRF-7 and type I IFN production by human plasmacytoid predendritic cells in response to TLR activation

Journal of Experimental Medicine ◽

10.1084/jem.20070763 ◽

2008 ◽

Vol 205 (2) ◽

pp. 315-322 ◽

Cited By ~ 166

Author(s):

Cristiana Guiducci ◽

Cristina Ghirelli ◽

Marie-Annick Marloie-Provost ◽

Tracy Matray ◽

Robert L. Coffman ◽

...

Keyword(s):

Nuclear Translocation ◽

Cell Types ◽

Nuclear Factor Κb ◽

Type I ◽

Endosomal Trafficking ◽

Type I Ifn ◽

Protein Levels ◽

Proinflammatory Responses ◽

Novel Target ◽

Factor Α

Plasmacytoid predendritic cells (pDCs) are the main producers of type I interferon (IFN) in response to Toll-like receptor (TLR) stimulation. Phosphatidylinositol-3 kinase (PI3K) has been shown to be activated by TLR triggering in multiple cell types; however, its role in pDC function is not known. We show that PI3K is activated by TLR stimulation in primary human pDCs and demonstrate, using specific inhibitors, that PI3K is required for type I IFN production by pDCs, both at the transcriptional and protein levels. Importantly, PI3K was not involved in other proinflammatory responses of pDCs, including tumor necrosis factor α and interleukin 6 production and DC differentiation. pDCs preferentially expressed the PI3K δ subunit, which was specifically involved in the control of type I IFN production. Although uptake and endosomal trafficking of TLR ligands were not affected in the presence of PI3K inhibitors, there was a dramatic defect in the nuclear translocation of IFN regulatory factor (IRF) 7, whereas nuclear factor κB activation was preserved. Thus, PI3K selectively controls type I IFN production by regulating IRF-7 nuclear translocation in human pDCs and could serve as a novel target to inhibit pathogenic type I IFN in autoimmune diseases.

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Pathology of Experimental CV777 Coronavirus Enteritis in Piglets. II. Electron Microscopic Study

Veterinary Pathology ◽

10.1177/030098588201900109 ◽

1982 ◽

Vol 19 (1) ◽

pp. 57-66 ◽

Cited By ~ 27

Author(s):

R. Ducatelle ◽

W. Coussement ◽

P. Debouck ◽

J. Hoorens

Keyword(s):

Epithelial Cells ◽

Lipid Droplets ◽

Clinical Signs ◽

Cell Types ◽

Electron Microscopic ◽

Time Intervals ◽

Colonic Epithelial Cells ◽

Severe Diarrhea ◽

Viral Particles ◽

Vacuolated Cells

Sixteen cesarean-derived, colostrum-deprived piglets were infected oronasally with CV777 coronavirus on the second or third day of life. Two uninfected piglets were controls. After an incubation period of 22 hours to 36 hours, all principals showed severe diarrhea. The piglets were killed at different time intervals. Viral particles were found in the jejunal villous epithelial cells from 18 hours after infection until four days after the beginning of diarrhea. In the colonic epithelial cells, viral particles and degenerative lesions were found only in the piglet killed 36 hours after onset of diarrhea. Degenerative lesions in the enterocytes began at 18 hours after infection and were most pronounced in the jejunum at the onset of clinical signs. From 24 hours on after the onset of clinical signs, three cell types were found: degenerated virus-containing enterocytes; cuboidal cells; and columnar, highly vacuolated cells containing lipid droplets.

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Probiotics inhibit nuclear factor-κB and induce heat shock proteins in colonic epithelial cells through proteasome inhibition

Gastroenterology ◽

10.1053/j.gastro.2004.09.001 ◽

2004 ◽

Vol 127 (5) ◽

pp. 1474-1487 ◽

Cited By ~ 220

Author(s):

Elaine O. Petrof ◽

Keishi Kojima ◽

Mark J. Ropeleski ◽

Mark W. Musch ◽

Yun Tao ◽

...

Keyword(s):

Heat Shock ◽

Epithelial Cells ◽

Heat Shock Proteins ◽

Proteasome Inhibition ◽

Nuclear Factor Κb ◽

Nuclear Factor ◽

Colonic Epithelial Cells ◽

Shock Proteins

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Regulation of Proinflammatory Cytokine Expression in Primary Mouse Astrocytes by Coronavirus Infection

Journal of Virology ◽

10.1128/jvi.01103-09 ◽

2009 ◽

Vol 83 (23) ◽

pp. 12204-12214 ◽

Cited By ~ 13

Author(s):

Dongdong Yu ◽

Hongqing Zhu ◽

Yin Liu ◽

Jianzhong Cao ◽

Xuming Zhang

Keyword(s):

Signaling Pathway ◽

Proinflammatory Cytokines ◽

Hepatitis Virus ◽

Cell Types ◽

Nuclear Factor Κb ◽

Small Interfering Rnas ◽

Necrosis Factor Alpha ◽

Tnf Α ◽

Primary Mouse ◽

Signaling Events

ABSTRACT Previous studies have shown that proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6), are differentially induced in primary mouse astrocytes by mouse hepatitis virus strain A59 (MHV-A59) and MHV-2. However, the signaling events that trigger TNF-α and IL-6 induction in these cells upon MHV infection remain unknown. In this study, we explored the potential signaling events. We found that induction of TNF-α and IL-6 occurred as early as 2 h postinfection and was completely dependent on viral replication. Using inhibitors specific for three mitogen-activated protein kinases, we showed that induction of TNF-α and IL-6 by MHV-A59 infection was mediated through activation of the Janus N-terminal kinase signaling pathway, but not through the extracellular signal-regulated kinase or p38 signaling pathway. This finding was further confirmed with knockdown experiments using small interfering RNAs specific for Janus N-terminal kinase. Interestingly, while nuclear factor κB (NF-κB), a key transcription factor required for the expression of proinflammatory cytokines in most cell types, was activated in astrocytes during MHV-A59 infection, disruption of the NF-κB pathway by peptide inhibitors did not significantly inhibit TNF-α and IL-6 expression. Furthermore, experiments using chimeric viruses demonstrated that the viral spike and nucleocapsid proteins, which play important roles in MHV pathogenicity in mice, are not responsible for the differential induction of the cytokines. These results illustrate the complexity of the regulatory mechanism by which MHV induces proinflammatory cytokines in primary astrocytes.

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ZBP-89, Sp1, and Nuclear Factor-κB Regulate Epithelial Neutrophil-activating Peptide-78 Gene Expression in Caco-2 Human Colonic Epithelial Cells

Journal of Biological Chemistry ◽

10.1074/jbc.m107838200 ◽

2001 ◽

Vol 276 (47) ◽

pp. 43713-43722 ◽

Cited By ~ 60

Author(s):

Andrew C. Keates ◽

Sarah Keates ◽

John H. Kwon ◽

Kristen O. Arseneau ◽

David J. Law ◽

...

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Nuclear Factor Κb ◽

Nuclear Factor ◽

Colonic Epithelial Cells

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Small Rab GTPase Rab7b Promotes Megakaryocytic Differentiation by Enhancing IL-6 Production and STAT3-GATA-1 Association.

Blood ◽

10.1182/blood.v116.21.1549.1549 ◽

2010 ◽

Vol 116 (21) ◽

pp. 1549-1549

Author(s):

Donghua He ◽

Taoyong Chen ◽

Mingjing Yang ◽

Xuhui Zhu ◽

Xuetao Cao ◽

...

Keyword(s):

Neutralizing Antibodies ◽

Conflicts Of Interest ◽

K562 Cells ◽

Cell Types ◽

Nuclear Factor Κb ◽

Small Gtpase ◽

Rab Gtpase ◽

Differentiation Markers ◽

Megakaryocytic Differentiation ◽

Morphological Alterations

Abstract Abstract 1549 Interleukin 6 (IL-6) is a pleiotropic cytokine acting on a variety of cell types, and plays important roles in hematopoiesis. GATA-1 (GATA binding protein 1) is an important transcription factor involved in either megakaryocytic or erythrocytic differentiation. However, the mechanisms for IL-6-induced megakaryocytic differentiation and regulation of GATA-1 have not been fully elucidated. By using phorbol-12-myristate-13-acetate (PMA)-induced megakaryocytic differentiation of K562 cells as a model, we investigated the roles of Rab7b, a late endosome/lysosome-localized myeloid small GTPase, in megakaryocytic differentiation. We find that Rab7b can promote PMA-induced megakaryocytic differentiation, as evidenced by typical morphological alterations, increased fibronectin-specific adhesion, increased polyploidy formation, and increased expression of CD41a. The GTP-bound status and lysosomal localization of Rab7b are required for promotion of K562 megakaryocytic differentiation, which can be blocked by inhibitor of nuclear factor κB (NF-κB) and neutralizing antibodies for IL-6 and gp130. In Rab7b-silenced K562 cells, PMA-induced activation of NF-κB, IL-6 production and megakaryocytic differentiation are impaired. Furthermore, we demonstrate that IL-6-induced activation of signal transducer and activator of transcription 3 (STAT3) and the subsequent association of STAT3 with GATA-1 may contribute to PMA-induced and Rab7b-mediated transcriptional upregulation of megakaryocytic differentiation markers. Therefore, our data suggest that Rab7b may play important roles in megakaryopoiesis by activating NF-κB and promoting IL-6 production. Our study also indicates that the IL-6-induced association of STAT3 with GATA-1 may favor megakaryopoiesis. Disclosures: No relevant conflicts of interest to declare.

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