Characterization of rabbit ileal receptors for Clostridium difficile toxin A. Evidence for a receptor-coupled G protein.

Pothoulakis, C; LaMont, J. Thomas; Eglow, R.; Gao, Ning; Rubins, Jeffrey B.; Theoharides, Theoharis C.; Dickey, Burton F.

doi:10.1172/jci115267

Cited by 74 publications

(56 citation statements)

References 49 publications

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“…Mouse ileal loops were ligated in anesthetized animals via laparotomy and injected with 0.15 ml of purified C. difficile toxin A (10 g) or buffer, as previously described (29). The purification of toxin A from toxigenic C. difficile strain 10465 (American Type Culture Collection) cultures has been previously described by us (34). In the experiments involving treatment with astressin 2B (Neurocrine Biosciences), CD1 male mice (n ϭ 7-8/group) were injected i.p.…”

Section: Induction Of Intestinal Inflammationmentioning

confidence: 99%

Corticotropin-Releasing Hormone Receptor 2-Deficient Mice Have Reduced Intestinal Inflammatory Responses

Kokkotou

Torres

Moss

et al. 2006

The Journal of Immunology

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Corticotropin-releasing hormone (CRH) and urocortins (Ucn) bind with various affinities to two G-protein-coupled receptors, CRHR1 and CRHR2, which are expressed in brain and in peripheral tissues, including immune cells. CRHR2-deficient mice display anxiety-like behavior, hypersensitivity to stress, altered feeding behavior and metabolism, and cardiovascular abnormalities. However, the phenotype of these mice in inflammatory responses has not been determined. In the present study we found that compared with wild-type CRHR2-null mice developed substantially reduced intestinal inflammation and had lower intestinal mRNA expression of the potent chemoattractants keratinocyte chemokine and monocyte chemoattractant protein 1 following intraluminal exposure to Clostridium difficile toxin A, a potent enterotoxin that mediates antibiotic-associated diarrhea and colitis in humans. This effect was recapitulated by administration of astressin 2B, a selective CRHR2 antagonist, before toxin A exposure. Moreover, Ab array analysis revealed reduced expression of several inflammatory chemokines, including keratinocyte chemokine and monocyte chemoattractant protein 1 in toxin A-exposed mice pretreated with astressin 2B. Real-time RT-PCR of wild-type mouse intestine showed that only UcnII, but not other Ucn, was significantly up-regulated by ileal administration of toxin A at 4 h compared with buffer exposure. We also found that human colonic epithelial HT-29 cells express CRHR2α mRNA, whereas expression of β and γ spliced variants was minimal. Moreover, treatment of HT-29 cells with UcnII, which binds exclusively to CRHR2, stimulated expression of IL-8 and monocyte chemoattractant protein 1. Taken together, these results provide direct evidence that CRHR2 mediates intestinal inflammatory responses via release of proinflammatory mediators at the colonocyte level.

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Section: Induction Of Intestinal Inflammationmentioning

confidence: 99%

Corticotropin-Releasing Hormone Receptor 2-Deficient Mice Have Reduced Intestinal Inflammatory Responses

Kokkotou

Torres

Moss

et al. 2006

The Journal of Immunology

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“…Toxin A was purified to homogeneity from broth culture supernatants of C. difficile strain 10,463, as described (31). Enterotoxicity and cytotoxicity of toxin A were assessed as described (32,33).…”

Section: Materials [mentioning

confidence: 99%

“…Enterotoxicity and cytotoxicity of toxin A were assessed as described (32,33). A dose of 5 g of purified toxin A was used in all experiments since previous studies showed that this dose induces fluid secretion, increases mannitol permeability, and causes an acute inflammatory infiltrate in rat ileal loops in vivo (21,22,(31)(32)(33). SP was purchased from Phoenix Laboratories (Belmont, CA), whereas the SP antagonist CP-96,345 and its 2R,3R inactive enantiomer, CP-96,344, were generously provided by Pfizer Diagnostics.…”

Section: Materials [mentioning

confidence: 99%

Increased substance P responses in dorsal root ganglia and intestinal macrophages duringClostridium difficiletoxin A enteritis in rats

Castagliuolo

Keates

Qiu

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

155

124

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Previously we reported that pretreatment of rats with the substance P (SP) antagonist CP-96,345 inhibits the enterotoxic responses following administration of toxin A from Clostridium difficile into ileal loops, indicating that SP participates in the intestinal responses to this toxin. We now report that injection of toxin A into rat ileum causes a rapid increase in SP content in lumbar dorsal root ganglia (DRG) and mucosal scrapings 30-60 min after toxin A administration. Toxin A-mediated f luid secretion, mannitol permeability, and ileal histologic damage is significantly increased only after 2 hr. Toxin A also causes an increase in the abundance of SP mRNA in lumbar DRG and ileal mucosa as measured by reverse transcription-PCR. Lamina propria macrophages (LPMs) obtained from toxin A-injected loops release greater amounts of tumor necrosis factor ␣ (TNF␣) and SP as compared with LPMs isolated from buffer-injected loops (P < 0.01). Pretreatment of rats with the SP antagonist CP-96,345 inhibits toxin A-mediated TNF␣ release from isolated LPMs, whereas an inactive enantiomer (CP-96,344) of the SP antagonist has no effect. LPMs obtained from toxin A-injected ileal loops incubated in vitro with SP (10 ؊8 to 10 ؊9 M) show enhanced TNF␣ secretion, whereas LPMs isolated from buffer-injected loops do not respond to SP. In addition, LPMs obtained from toxin A-injected ileal loops incubated in vitro with CP-96,345 showed a diminished TNF␣ release. Our results indicate that activated LPMs secrete SP during toxin A enteritis that can lead to secretion of cytokines, suggesting an autocrine͞paracrine regulation of cytokine secretion by SP from LPMs during intestinal inf lammation.Substance P (SP), an 11-aa peptide member of the tachykinin family originally isolated by Chang and Leeman (1), is a peptide distributed throughout the central and peripheral nervous system. In the intestine, SP has been found in capsaicin-sensitive sensory neurons (2), enteric neurons (3), as well as intestinal enteroendocrine cells (4). SP is also synthesized in the cell bodies of the dorsal root ganglia (DRG) (5), and evidence indicates that release of SP from DRG to spinal cord mediates nociceptive and inflammatory stimuli (6-8). Recently, Reinshagen et al. (9) reported decreased levels of SP in the DRG of rabbits 48 hr after induction of colitis, suggesting that SP may be released from sensory neurons during the acute phase of inflammation. However, there are no studies specifically evaluating the SP content in the DRG during acute intestinal inflammation mediated by bacterial enterotoxins.In addition to its role as a neurotransmitter, SP also participates in immune and inflammatory responses. Mast cells (10), polymorphonuclear leukocytes (11), T lymphocytes (12, 13), and macrophages (14) can respond to SP, indicating that the effects of SP during inflammation may be mediated by direct activation of these cells. SP levels are also elevated in inflamed tissues (15-17), and increased binding sites for SP have been demonstrated at sites o...

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“…Glycolipide ou glycoprotéine [91,120,153] (nLc5Cer, Ag X, Ag Y, Ag I) [139,147] Sucrase isolmaltase [121] Clostridium perfringens…”

Section: Clostridium Difficilementioning

confidence: 99%

“…Le récepteur de CDTa a été le plus étudié parmi ceux des entérotoxines ayant une activité dirigée contre l'actine [20,91,120,121,129,139,147,152]. CDTa est cytotonique et peut exercer aussi des effets cytotoxiques [153].…”

Section: Réarragement Du Cytosqueletteunclassified

Les récepteurs des entérotoxines bactériennes

Rousset

2000

Vet. Res.

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-Bacterial enterotoxin receptors. Enteric bacterial toxins display a great diversity in their structure, molecular weight and mechanism of action. The interaction of enterotoxins with the intestinal mucosa either leads to a direct effect on the cell membrane or an effect on signal transduction within eukaryotic cells. However, before a toxin can affect a cell, it must after its secretion by a microorganism, recognise and bind to a specific surface molecule, its receptor. Membrane receptors of bacterial enterotoxins have been identified as protein, glycoprotein or glycolipid in nature. The chemical nature of the molecules acting as receptors is crucial and during evolution they have been carefully selected. Some toxins, after their interaction with a receptor molecule, will transduce a signal across the cell membrane while remaining at the cell surface. Other toxins, after this initial binding step with a receptor, will be internalised. Others can form pores leading to leakage of cellular components and cell lysis. Receptors that have been identified often comprise a saccharidic chain that is directly involved in the recognition and binding of the toxin. Today, models explaining toxin-receptor interactions are more complex, including multistep events. This review summarises the knowledge of the interactions between bacterial toxins and membrane receptors present on intestinal mucosa. receptor / intestine / enterotoxin / binding epitope / glycosphingolipidRésumé -Les toxines bactériennes entériques présentent une grande diversité autant dans leur structure que dans leur poids moléculaire et leur mécanisme d'action. L'interaction des entérotoxines avec la muqueuse intestinale conduit soit à un effet direct sur la paroi cellulaire de la cellule hôte, soit à un dérèglement des voies de signalisation de celle-ci. Toutefois, avant même d'affecter la cellule cible, la toxine sécrétée par le micro-organisme devra reconnaître et s'attacher à une molécule présente à la surface cellulaire, son récepteur. Les récepteurs membranaires des entérotoxines bactériennes peuvent être de nature protéique, glycoprotéique ou glycolipidique. La nature chimique de ces récepteurs, sur laquelle repose la spécificité, est primordiale et au cours de l'évolution ceuxci ont été soigneusement sélectionnés. Certaines toxines, une fois en contact avec leur récepteur, envoient un signal à l'intérieur de la cellule tout en demeurant à la surface alors que d'autres toxines sont internalisées. Enfin, certaines toxines bactériennes peuvent former des pores dans la membrane Vet. Res. 31 (2000)

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Characterization of rabbit ileal receptors for Clostridium difficile toxin A. Evidence for a receptor-coupled G protein.

Cited by 74 publications

References 49 publications

Corticotropin-Releasing Hormone Receptor 2-Deficient Mice Have Reduced Intestinal Inflammatory Responses

Corticotropin-Releasing Hormone Receptor 2-Deficient Mice Have Reduced Intestinal Inflammatory Responses

Increased substance P responses in dorsal root ganglia and intestinal macrophages duringClostridium difficiletoxin A enteritis in rats

Les récepteurs des entérotoxines bactériennes

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