Protective Immunization of Mice with an Active-Site Mutant of Subtilase Cytotoxin of Shiga Toxin-Producing
            <i>Escherichia coli</i>

Talbot, Ursula M.; Paton, James C.; Paton, Adrienne W.

doi:10.1128/iai.73.7.4432-4436.2005

Cited by 28 publications

(21 citation statements)

References 20 publications

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“…SubAB and SubA A272 B were purified by Ni-NTA chromatography as previously described (Paton et al, 2004;Paton et al, 2006;Talbot et al, 2005). Peak fractions were pooled, dialyzed against phosphate-buffered saline and stored in 50% glycerol at −20°C, before addition to cell culture media at a final 1 µg/ml concentration (Paton et al, 2006).…”

Section: Antibodies Reagents and Plasmidsmentioning

confidence: 99%

Decreased ER-associated degradation of α-TCR induced by Grp78 depletion with the SubAB cytotoxin

Lass

Kujawa

McConnell

et al. 2008

The International Journal of Biochemistry & Cell Biology

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HeLa cells stably expressing the α chain of T-cell receptor (αTCR), a model substrate of ERAD (ERassociated degradation), were used to analyze the effects of BiP/Grp78 depletion by the SubAB cytotoxin. SubAB induced XBP1 splicing, followed by JNK phosphorylation, eIF2α phosphorylation, upregulation of ATF3/4 and partial ATF6 cleavage. Other markers of ER stress, including elements of ER-associated degradation (ERAD) pathway, as well as markers of cytoplasmic stress, were not induced. SubAB treatment decreased absolute levels of αTCR, which was caused by inhibition of protein synthesis. At the same time, the half-life of αTCR was extended almost fourfold from 70 min to 210 min, suggesting that BiP normally facilitates ERAD. Depletion ofp97/VCP partially rescued SubAB-induced depletion of αTCR, confirming the role of VCP in ERAD of αTCR. It therefore appears that ERAD of αTCR is driven by at least two different ATPase systems located at two sides of the ER membrane, BiP located on the lumenal side, while p97/ VCP on the cytoplasmic side. While SubAB altered cell morphology by inducing cytoplasm vacuolization and accumulation of lipid droplets, caspase activation was partial and subsided after prolonged incubation. Expression of CHOP/GADD153 occurred only after prolonged incubation and was not associated with apoptosis.

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Section: Antibodies Reagents and Plasmidsmentioning

confidence: 99%

Decreased ER-associated degradation of α-TCR induced by Grp78 depletion with the SubAB cytotoxin

Lass

Kujawa

McConnell

et al. 2008

The International Journal of Biochemistry & Cell Biology

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“…SubAB and SubA A272 B were purified as described previously (1,22). SubA A272 B is a SubAB active-site mutant with a Ser 272 -Ala mutation in the A subunit.…”

Section: Methodsmentioning

confidence: 99%

Differential Effects of Escherichia coli Subtilase Cytotoxin and Shiga Toxin 2 on Chemokine and Proinflammatory Cytokine Expression in Human Macrophage, Colonic Epithelial, and Brain Microvascular Endothelial Cell Lines

et al. 2014

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Subtilase cytotoxin (SubAB) is the prototype of a recently emerged family of AB5 cytotoxins produced by Shiga-toxigenic Escherichia coli (STEC). Its mechanism of action involves highly specific A-subunit-mediated proteolytic cleavage of the essential endoplasmic reticulum (ER) chaperone BiP. Our previous in vivo studies showed that intraperitoneal injection of purified SubAB causes a major redistribution of leukocytes and elevated leukocyte apoptosis in mice, as well as profound splenic atrophy. In the current study, we investigated selected chemokine and proinflammatory cytokine responses to treatment with SubAB, a nontoxic derivative (SubA A272 B), or Shiga toxin 2 (Stx2) in human macrophage (U937), brain microvascular endothelial (HBMEC), and colonic epithelial (HCT-8) cell lines, at the levels of secreted protein, cell-associated protein, and gene expression. Stx2 treatment upregulated expression of chemokines and cytokines at both the protein and mRNA levels. In contrast, SubAB induced significant decreases in secreted interleukin-8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) in all three tested cell lines and a significant decrease in secreted IL-6 in HBMECs. The downregulation of secreted chemokines or cytokines was not observed in SubA A272 B-treated cells, indicating a requirement for BiP cleavage. The downregulation of secreted chemokines and cytokines by SubAB was not reflected at the mRNA and cell-associated protein levels, suggesting a SubAB-induced export defect.

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“…Recombinant SubAB and SubA A272 B mutant toxins were produced in Escherichia coli and purified by Ni-nitrilotriacetic acid chromatography, as previously described (31,42). The 293 cells were either left uninfected, mock infected with heat-inactivated virus, or DENV infected, as described above.…”

Section: Methodsmentioning

confidence: 99%

Dengue Virus Infection Induces Upregulation of GRP78, Which Acts To Chaperone Viral Antigen Production

Wati

Soo

Zilm

et al. 2009

J Virol

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Dengue virus (DENV) pathogenesis is related to the host responses to viral infection within target cells, and therefore, this study assessed intracellular changes in host proteins following DENV infection. Two-dimensional gel electrophoresis and mass spectrometry identified upregulation of the host endoplasmic reticulum (ER) chaperone GRP78 in K562 cells following DENV infection, in the absence of virus-induced cell death. Upregulation of GRP78 in DENV-infected cells was confirmed by immunostaining and confocal microscopy and by Western blot analysis and was also observed in DENV-infected primary monocyte-derived macrophages, a natural target cell type for DENV infection. GRP78 was upregulated in both DENV antigen-positive and -negative cells in the DENV-infected culture, suggesting a bystander effect, with the highest GRP78 levels coincident with high-level DENV antigen production and infectious-virus release. Transfection of target cells to express GRP78 prior to DENV challenge did not affect subsequent DENV infection, but cleavage of GRP78 with the SubAB toxin, during an established DENV infection, yielded a 10-to 100-fold decrease in infectiousvirus release, loss of intracellular DENV particles, and a dramatic decrease in intracellular DENV antigen. However, DENV RNA levels were unchanged, indicating normal DENV RNA replication but altered DENV antigen levels in the absence of GRP78. Thus, GRP78 is upregulated by DENV infection and is necessary for DENV antigen production and/or accumulation. This may be a common requirement for viruses such as flaviviruses that depend heavily on the ER for coordinated protein production and processing.The pathogenesis of dengue virus (DENV) disease is multifactorial, and many of the clinical manifestations of the disease, including the life-threatening DENV-induced hemorrhage, may be mediated by the host responses to infection. Many studies have defined altered host responses during DENV infection, including activation of T cells (19) and altered levels of circulating factors in patients (13) and altered release of cytokines and chemokines from DENV-infected cells (8). Transcriptome analyses of DENV-infected endothelial cells (23, 45), HepG2 cells (9), circulating patient cells (39), or peripheral blood mononuclear cells from DENV-infected macaque monkeys (37) have identified alterations in transcripts involved in a variety of cellular processes, including the innate immune response, cell signaling, and metabolic processes. A recent study examined proteomic changes in DENVinfected HepG2 cells and identified 17 altered cellular proteins, including 2 proteins for which the changes were confirmed (32). In the current study, we performed a proteomic analysis of changes due to DENV infection in a target cell population that is relevant to a natural DENV infection and in which DENV-induced cytopathic effect (CPE) and the cellular death response are absent. Two-dimensional gel electrophoresis (2DGE) identified upregulation of glucose-regulated protein 78 (GRP78), otherwise known a...

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Protective Immunization of Mice with an Active-Site Mutant of Subtilase Cytotoxin of Shiga Toxin-Producing Escherichia coli

Cited by 28 publications

References 20 publications

Decreased ER-associated degradation of α-TCR induced by Grp78 depletion with the SubAB cytotoxin

Decreased ER-associated degradation of α-TCR induced by Grp78 depletion with the SubAB cytotoxin

Differential Effects of Escherichia coli Subtilase Cytotoxin and Shiga Toxin 2 on Chemokine and Proinflammatory Cytokine Expression in Human Macrophage, Colonic Epithelial, and Brain Microvascular Endothelial Cell Lines

Dengue Virus Infection Induces Upregulation of GRP78, Which Acts To Chaperone Viral Antigen Production

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