1
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Fekete E, Allain T, Buret A. Altered Mucosal Glycosylation Patterns during
Giardia spp
. Infection are Time‐Dependent and Tissue‐Specific. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r3266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elena Fekete
- Department of Biological SciencesUniversity of CalgaryCalgaryAB
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2
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Lockhart J, Allain T, Buret A, Morck D. Anaerobic Bacterial Biofilms Inhibit Neutrophil Responses via the Release of Stable Small‐Molecule Effectors. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r2675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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3
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Sosnowski O, Allain T, Fekete E, Mckay DM, Buret A. A56 TUFT CELL RESPONSES DURING ACUTE- AND LATE-STAGE GIARDIA INFECTION. J Can Assoc Gastroenterol 2022. [PMCID: PMC8859371 DOI: 10.1093/jcag/gwab049.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background Epithelial tuft cells can detect and respond to enteric infections and appear to help clear some intestinal parasites. Through tuft cell luminal surface receptors, tuft cells can sense ligands directly supplied by a parasite, or indirectly via excretory/secretory products. We hypothesize that microbiome alterations may also modulate tuft cell-derived gut responses. Tuft cells release the alarmin cytokine IL-25 which, upon acting on type 2 innate lymphoid cells (ILC2), ultimately lead to tuft and goblet cell hyperplasia. Upon helminth infections, tuft and goblet cell hyperplasia occurred concurrently, and coincided with the peak of infection. The role of tuft cells in infections with the enteric protozoan parasite Giardia sp. is unknown. The aim of our study is to characterize how tuft cells may be implicated in the pathophysiology of giardiasis, in an attempt to uncover novel regulatory pathways of intestinal physiology. Aims In this study, we aim to characterise the tuft cell response to Giardia infection during acute and late stages of infection and to assess goblet cell hyperplasia. Methods 5–7-week-old C57BL/6 mice and tuft cell-deficient mice ( Pou2f3-/-) were orally gavaged with 5x104Giardia muris trophozoites and scarified at days 4, 11 and 21 post-infection. Parasite burden was assessed in the duodenum. Immunofluorescence (IF) staining of doublecortin-like kinase 1 (DCLK1) – a marker of tuft cells – was performed on C57BL/6 mice jejunum tissue sections and the number of tuft cells was quantified. Goblet cells were quantified in PAS/AB-stained jejunum sections. Quantitative PCR (qPCR) was performed on Dclk1, the epithelial secretory cell transcription factor Atoh1, and the mucus gene Muc2. Results G. muris infected C57BL/6 mice displayed high parasite load at days 4 ( p<0.05) and 11 ( p<0.05), with no or low parasite burden at day 21 ( p<0.05). Pou2f3-/- mice showed less robust parasite burden at days 4 and 11, and similar low parasite burden at day 21, compared to WT mice. At day 21, tuft cell (DCLK1+) counts ( p<0.05) and Dclk1 mRNA expression levels were increased in Giardia infected mice in the jejunum. Goblet cell number and Atoh1 and Muc2 expression were increased at day 4 post-infection. Conclusions The data demonstrate that tuft cells expand late in Giardia infection, suggesting that upon parasite infection, tuft cells may possess roles in tissue repair or clearance of infection. Tuft cell-deficient mice ( Pou2f3-/-) had lower parasite burden early in Giardia infection, counter-intuitively suggesting that tuft cells may facilitate trophozoite colonization, further highlighting the novelty of these findings. The crosstalk between tuft cells, Giardia, and other host responses during acute and late stages of infection remain to be fully characterised. Funding Agencies NSERC
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Affiliation(s)
- O Sosnowski
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - T Allain
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - E Fekete
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - D M Mckay
- Physiology & Pharmacology, Uni. Calgary, Calgary, AB, Canada
| | - A Buret
- Biological Sciences, University of Calgary, Calgary, AB, Canada
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4
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Siddiq A, Allain T, Dong G, Olivier M, Buret A. Giardia
releases extracellular vesicles which can modulate growth and behavior of commensal bacteria. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.01946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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5
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Fekete E, Amat C, Allain T, Mihara K, Hollenberg M, Chadee K, Buret A. Structural and Chemical Alterations to the Intestinal Mucus Barrier during
Giardia duodenalis
Infection. FASEB J 2021. [DOI: 10.1096/fasebj.2021.35.s1.02078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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6
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Fekete E, Amat CB, Allain T, Hollenberg M, Mihara K, Chadee K, Buret A. A50 MODULATION OF GOBLET CELL ACTIVITY DURING GIARDIA DUODENALIS INFECTION: A ROLE FOR PAR2. J Can Assoc Gastroenterol 2021. [DOI: 10.1093/jcag/gwab002.048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Background
Giardia duodenalis has been shown to alter the structure of the intestinal mucus layers during infection via obscure mechanisms. We hypothesize that goblet cell activity may be disrupted in part due to proteolytic activation of protease-activated receptor 2 (PAR2) by Giardia proteases, resulting in disruption of mucus production and secretion by intestinal goblet cells.
Aims
Characterize alterations in goblet cell activity during Giardia infection, focusing on the roles of Giardia protease activity and PAR2.
Methods
Chinese hamster ovary cells transfected with nano-luciferase tagged PAR2 were incubated with Giardia NF or GSM trophozoites. Cleavage within the activation domain results in release of enzymes into the supernatant. Luminescence in the supernatant was measured as an indication of PAR cleavage by Giardia.
LS174T, a human colonic mucus-producing cell line, was infected with Giardia trophozoites (isolates NF, WB, S2, and GSM). Prior to infection, trophozoites were treated with E64, a broad-spectrum cysteine protease inhibitor, and LS174T were treated with a PAR2 antagonist, a calcium chelator, or an ERK1/2 inhibitor. Quantitative PCR (qPCR) was performed for the MUC2 mucin gene.
Wild-type (WT) and PAR2 knockout (KO) mice were infected with Giardia. Colonic mucus was stained using fluorescein-coupled wheat-germ agglutinin (WGA), and qPCR was performed for Muc2 and Muc5ac.
Results
Giardia trophozoites cleaved PAR2 within the N-terminal activation domain in a cysteine protease-dependent manner. Cleavage was isolate dependent, with isolates that show higher protease activity cleaving at a higher rate.
High protease activity Giardia isolates increased MUC2 gene expression in LS714T. This increase was attenuated by inhibition of Giardia cysteine protease activity, and by antagonism of PAR2, inhibition of calcium release, or inhibition of ERK1/2 activity in LS174T cells.
Both Muc2 and Muc5ac expression were upregulated in the colons of WT mice in response to Giardia infection, while in the jejunum Muc2 expression decreased and Muc5ac expression increased. In KO, no changes in gene expression were seen in the colon in response to Giardia infection, while in the jejunum, Muc2 expression was unchanged and Muc5ac expression decreased. Both WT infected and KO noninfected mice showed thinning of the colonic mucus layer compared to WT controls. There was some recovery in thickness in KO infected mice.
Conclusions
PAR2 plays a significant role in the regulation of mucin gene expression in mice and in a human colonic cell line. Results suggest that Giardia cysteine proteases cleave and activate PAR2, leading to calcium release and activation of the MAPK pathway in goblet cells, ultimately leading to altered mucin gene expression. Findings identify a novel regulatory pathway for mucus production by intestinal goblet cells.
Funding Agencies
CAG, CCC
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Affiliation(s)
- E Fekete
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - C B Amat
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - T Allain
- University of Calgary, Calgary, AB, Canada
| | - M Hollenberg
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - K Mihara
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - K Chadee
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - A Buret
- Biological Sciences, University of Calgary, Calgary, AB, Canada
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7
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Siddiq A, Allain T, Dong G, Olivier M, Buret A. Giardia
extracellular vesicles disrupt intestinal epithelial junctions and inhibit the growth of commensal bacteria while increasing their swimming motility. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.00515] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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8
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Fekete ER, Amat C, Allain T, Mihara K, Hollenberg M, Chadee K, Buret A. Alterations to Mucus Production and Secretion during
Giardia
Infection Involve
Giardia
Protease Activity and PAR2 Activation. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.02365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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9
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Lockhart J, Buret A, Morck D. Biofilm and Planktonic Bacteria Differentially Express a Small Molecule (<3kD), Heat‐Stable, Protease‐Resistant Factor that Affects Bovine Neutrophil Function in a NF‐Kappa β‐Independent Mechanism. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.04816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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10
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Shute AJ, Callejas Pina BE, Jayme TS, Wang A, Buret A, McKay DM. A264 HELMINTH-INFECTION MOBILIZES HOST AND MICROBIAL FACTORS THAT CO-OPERATE TO SUPPRESS CHEMICAL-INDUCED COLITIS IN MICE. J Can Assoc Gastroenterol 2020. [DOI: 10.1093/jcag/gwz047.263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Background
Infection with helminth parasites suppresses inflammation in murine model systems; for example, IL-10 is important in Hymenolepis diminuta-inhibition of DNBS-induced colitis. Bacteria-derived products can have anti-inflammatory effects. Given that infection with H. diminuta, or other parasitic worms, results in perturbation of the gut microbiota, the present study tested a role for bacteria in helminth-suppression of colitis by assessing reciprocity between IL-10 and butyrate signaling in the amelioration of colitis.
Aims
To determine if a functional relationship exists between IL-10 and butyrate in the inhibition of colitis observed following infection with the lumen-dwelling tapeworm, Hymenolepis diminuta.
Methods
Colitis was induced in male BALB/c mice by intra-rectal dinitrobenzene sulphonic acid (DNBS) (3 mg/~22g mouse), with necropsy and assessment 3 days later. Mice received either infection with five H. diminuta cysticercoids by gavage or daily butyrate enemas or acetate in their drinking water. Immunostaining assessed IL-10R protein expression on formalin-fixed sections of colon. The murine IEC4.1 epithelial cell line and epithelial organoids were treated with butyrate and mRNA for the IL10Rα chain assessed, as was colonic tissue from mice.
Results
Mice infected with H. diminuta or receiving butyrate enemas (n=8–12) were protected from DNBS-induced colitis as gauged by colon length, and macroscopic disease and histopathology scores. Addition of acetate to the drinking water resulted in a more modest anti-colitic effect. Suppression of colitis was accompanied by increased epithelial expression of IL-10 in butyrate- and H. diminuta-treated mice, with the later also showing upregulation of the IL-10R on lamina propria cells; an effect negated by co-treating the mice with broad spectrum antibiotics. In vitro analyses revealed increased IL10Rα mRNA in butyrate-treated epithelia (n=4).
Conclusions
This study begins to tease apart the host (i.e. IL-10) and bacterial (i.e. butyrate) molecules that mediate H. diminuta-evoked suppression of colitis in a murine model. These proof-of-principle data suggest that knowledge of the individual patient (i.e. immunological basis of their disease and their microbiota) may be a critical determinant of the success or failure of helminth therapy.
Funding Agencies
CAG, CCCNSERC
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Affiliation(s)
- A J Shute
- Phisiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - B E Callejas Pina
- Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - T S Jayme
- University of Calgary, Calgary, AB, Canada
| | - A Wang
- Phisiology and Pharmacology, University of Calgary, Calgary, AB, Canada
| | - A Buret
- University of Calgary, Calgary, AB, Canada
| | - D M McKay
- University of Calgary, Calgary, AB, Canada
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11
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Fekete E, Amat C, Allain T, Mihara K, Hollenberg M, Chadee K, Buret A. Giardia
‐Induced Alterations to Intestinal Mucus Production Involve Protease‐Activated Receptor‐2‐Mediated Activation of MAPK and Calcium Release. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.38.10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Elena Fekete
- Biological SciencesUniversity of CalgaryCalgaryABCanada
| | | | | | - Koichiro Mihara
- Physiology and PharmacologyUniversity of CalgaryCalgaryABCanada
| | | | | | - Andre Buret
- Biological SciencesUniversity of CalgaryCalgaryABCanada
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12
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Fekete E, Amat CB, Allain T, Hollenberg M, Chadee K, Buret A. A158 ENTEROPATHOGEN CYSTEINE PROTEASES ALTER INTESTINAL MUCUS PRODUCTION VIA PROTEASE-ACTIVATED RECEPTOR-2: EFFECTS OF GIARDIA DUODENALIS. J Can Assoc Gastroenterol 2019. [DOI: 10.1093/jcag/gwz006.157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- E Fekete
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - C B Amat
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - T Allain
- University of Calgary, Calgary, AB, Canada
| | - M Hollenberg
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - K Chadee
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - A Buret
- University of Calgary, Calgary, AB, Canada
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13
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Wallace JL, Nagy P, Feener T, Allain T, Ditrói T, Vaughan D, Muscara M, de Nucci G, Buret A. A3 A PROOF-OF-CONCEPT, PHASE 2 CLINICAL TRIAL OF THE GI SAFETY OF A HYDROGEN SULFIDE-RELEASING ANTI-INFLAMMATORY DRUG (ATB-346). J Can Assoc Gastroenterol 2019. [DOI: 10.1093/jcag/gwz006.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- J L Wallace
- Physiology & Pharmacology, University of Calgary, Toronto, ON, Canada
| | - P Nagy
- National Institute of Oncology, Budapest, Hungary
| | - T Feener
- Physiology & Pharmacology, University of Calgary, Toronto, ON, Canada
| | - T Allain
- Physiology & Pharmacology, University of Calgary, Toronto, ON, Canada
| | - T Ditrói
- National Institute of Oncology, Budapest, Hungary
| | - D Vaughan
- Antibe Therapeutics Inc., Toronto, ON, Canada
| | - M Muscara
- University of Sao Paulo, Sao Paulo, Brazil
| | - G de Nucci
- University of Campinas, Campinas, Brazil
| | - A Buret
- University of Calgary, Calgary, AB, Canada
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14
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Allain T, Groves R, Lewis I, Buret A. A163
GIARDIA SP. METABOLOME : TOWARDS THE IDENTIFICATION OF NEW VIRULENCE FACTORS. J Can Assoc Gastroenterol 2019. [DOI: 10.1093/jcag/gwz006.162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- T Allain
- University of Calgary, Calgary, AB, Canada
| | - R Groves
- University of Calgary, Calgary, AB, Canada
| | - I Lewis
- University of Calgary, Calgary, AB, Canada
| | - A Buret
- University of Calgary, Calgary, AB, Canada
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15
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Lamache DD, Ruth M, Affan S, Feener T, Gregory M, McKenna N, Yates R, Buret A. Benefits of Antibiotics During Viral Infections: Immuno‐Modulating Properties of Tulathromycin in Porcine Reproductive and Respiratory Syndrome. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.817.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Moges Ruth
- Biological SciencesUniversity of CalgaryCalgaryABCanada
| | - Siddiq Affan
- Biological SciencesUniversity of CalgaryCalgaryABCanada
| | - Troy Feener
- Biological SciencesUniversity of CalgaryCalgaryABCanada
| | | | - Neil McKenna
- Comparative Biology and Experimental MedicineUniversity of CalgaryCalgaryABCanada
| | - Robin Yates
- Comparative Biology and Experimental MedicineUniversity of CalgaryCalgaryABCanada
- Biochemistry and Molecular BiologyUniversity of CalgaryCalgaryABCanada
| | - Andre Buret
- Biological SciencesUniversity of CalgaryCalgaryABCanada
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16
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Affiliation(s)
| | | | | | | | - Kris Chadee
- Microbiology, Immunology & Infectious DiseasesUniversity of CalgaryCalgaryABCanada
| | - Andre Buret
- Biological SciencesUniversity of CalgaryCalgaryABCanada
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17
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Manko A, Motta J, Cotton J, Oyeyemi A, Vallance B, Wallace JL, Buret A. A292 NLRP 3
-DEPENDENT PRODUCTION OF ANTIMICROBIAL PEPTIDES DURING CO-INFECTION WITH GIARDIA INTESTINALIS
AND E. COLI. J Can Assoc Gastroenterol 2018. [DOI: 10.1093/jcag/gwy008.293] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- A Manko
- Biological sciences, University of Calgary, Calgary, AB, Canada
| | - J Motta
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - J Cotton
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - A Oyeyemi
- University of Calgary, Calgary, AB, Canada
| | - B Vallance
- BC Children’s Hospital, Vancouver, BC, Canada
| | - J L Wallace
- Antibe Therapeutics Inc., Toronto, ON, Canada
| | - A Buret
- University of Calgary, Calgary, AB, Canada
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18
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Amat CB, Motta J, Chadee K, Buret A. A298 A SWITCH FROM MUC2 TRANSCRIPTION TO MUC5AC IS A COMPENSATORY MECHANISM AGAINST THE MUCOLYTIC ACTIVITY OF GIARDIA DUODENALIS. J Can Assoc Gastroenterol 2018. [DOI: 10.1093/jcag/gwy008.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- C B Amat
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - J Motta
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - K Chadee
- Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
| | - A Buret
- University of Calgary, Calgary, AB, Canada
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19
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Fekete E, Amat CB, Allain T, Saiffeddine M, Hollenberg M, Chadee K, Buret A. A7 THE ROLE OF PROTEASE-ACTIVATED RECEPTOR-2 IN GIARDIA INDUCED DISRUPTIONS OF THE INTESTINAL MUCUS LAYER. J Can Assoc Gastroenterol 2018. [DOI: 10.1093/jcag/gwy009.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- E Fekete
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - C B Amat
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - T Allain
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - M Saiffeddine
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - M Hollenberg
- Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - K Chadee
- Microbiology, Immunology and Infectious Diseases, University of Calgary, Calgary, AB, Canada
| | - A Buret
- University of Calgary, Calgary, AB, Canada
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20
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Affiliation(s)
- Christina Amat
- Biological SciencesUniversity of CalgaryCalgaryAlbertaCanada
- Inflammation Research Network University of CalgaryCalgaryAlbertaCanada
- Host‐Parasite Interactions University of CalgaryCalgaryAlbertaCanada
| | - Jean‐Paul Motta
- Biological SciencesUniversity of CalgaryCalgaryAlbertaCanada
- Inflammation Research Network University of CalgaryCalgaryAlbertaCanada
- Host‐Parasite Interactions University of CalgaryCalgaryAlbertaCanada
| | - Amol Bhargava
- Biological SciencesUniversity of CalgaryCalgaryAlbertaCanada
- Inflammation Research Network University of CalgaryCalgaryAlbertaCanada
- Host‐Parasite Interactions University of CalgaryCalgaryAlbertaCanada
| | - Kris Chadee
- Inflammation Research Network University of CalgaryCalgaryAlbertaCanada
- Microbiology and Infectious Diseases University of CalgaryCalgaryAlbertaCanada
- Host‐Parasite Interactions University of CalgaryCalgaryAlbertaCanada
| | - Andre Buret
- Biological SciencesUniversity of CalgaryCalgaryAlbertaCanada
- Inflammation Research Network University of CalgaryCalgaryAlbertaCanada
- Host‐Parasite Interactions University of CalgaryCalgaryAlbertaCanada
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21
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Gerbaba T, Gupta P, Wang X, Rioux K, Hansen D, Buret A. Enteropathogen‐induced toxicity of gut‐microbiota in
C. elegans
: a new model to investigate mechanisms of post‐infectious intestinal disorders (145.7). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.145.7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Teklu Gerbaba
- Biological Sciences University of CalgaryCalgaryABCanada
| | - Pratyush Gupta
- Biological Sciences University of CalgaryCalgaryABCanada
| | - Xin Wang
- Biological Sciences University of CalgaryCalgaryABCanada
| | - Kevin Rioux
- Department of Medicine University of CalgaryCalgaryABCanada
| | - Dave Hansen
- Biological Sciences University of CalgaryCalgaryABCanada
| | - Andre Buret
- Biological Sciences University of CalgaryCalgaryABCanada
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22
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Motta J, Flannigan K, Agbor T, Blackler R, Workentine M, Da Silva G, Buret A, Wallace J. Hydrogen sulfide protects from colitis: a possible role in stabilizing gut microbiota (898.3). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.898.3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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23
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Cotton J, Bhargava A, Ferraz J, Yates R, Beck P, Buret A. Giardia cathepsin B cysteine proteases degrade interleukin‐8 and attenuate interleukin‐8‐induced neutrophil chemotaxis (152.2). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.152.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- James Cotton
- Biological Sciences University of CalgaryCalgaryABCanada
| | - Amol Bhargava
- Biological Sciences University of CalgaryCalgaryABCanada
| | - Jose Ferraz
- Medicine University of CalgaryCalgaryABCanada
| | - Robin Yates
- Dept. of Biochemistry and Molecular Biology University of CalgaryCalgaryABCanada
| | - Paul Beck
- Medicine University of CalgaryCalgaryABCanada
| | - Andre Buret
- Biological Sciences University of CalgaryCalgaryABCanada
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Halliez M, Le Goff L, Francois A, Colasse E, Gargala G, Villena I, Favennec L, Lapointe T, Altier C, Buret A. Novel insights in post‐infectious irritable bowel syndrome in experimental giardiasis (650.15). FASEB J 2014. [DOI: 10.1096/fasebj.28.1_supplement.650.15] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Marie Halliez
- Department of Biological SciencesUniversity of CalgaryCalgaryABCanada
- Faculte DE medecine et DE pharmacie University of RouenRouenFrance
| | - Laetitia Le Goff
- Faculte DE medecine et DE pharmacie University of RouenRouenFrance
| | - Arnaud Francois
- Faculte DE medecine et DE pharmacie University of RouenRouenFrance
| | - Elodie Colasse
- Faculte DE medecine et DE pharmacie University of RouenRouenFrance
| | - Gilles Gargala
- Faculte DE medecine et DE pharmacie University of RouenRouenFrance
| | - Isabelle Villena
- Faculte DE medecine et DE pharmacie University of RouenRouenFrance
| | - Loic Favennec
- Faculte DE medecine et DE pharmacie University of RouenRouenFrance
| | - Tamia Lapointe
- Department of Physiology and Pharmacology University of CalgaryCalgaryABCanada
| | - Christophe Altier
- Department of Physiology and Pharmacology University of CalgaryCalgaryABCanada
| | - Andre Buret
- Department of Biological SciencesUniversity of CalgaryCalgaryABCanada
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Cotton J, Bhargava A, Ferraz J, Hollenberg M, Beck P, Buret A. Cleavage of interleukin‐8 and attenuation of neutrophil chemotaxis by a
Giardia
cathepsin B. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.131.8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- James Cotton
- Biological SciencesUniversity of CalgaryCalgaryABCanada
| | - Amol Bhargava
- Biological SciencesUniversity of CalgaryCalgaryABCanada
| | - Jose Ferraz
- MedicineUniversity of CalgaryCalgaryABCanada
| | | | - Paul Beck
- MedicineUniversity of CalgaryCalgaryABCanada
| | - Andre Buret
- Biological SciencesUniversity of CalgaryCalgaryABCanada
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Beatty J, Akierman S, Rioux K, Beck P, McKnight W, Feener T, Wallace J, Buret A. Gut microbiota biofilm disruptions by Giardia: Pathology in human enterocytes and germ‐free mice. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.131.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jennifer Beatty
- Biological ScienceUniversity of CalgaryCalgaryABCanada
- Inflammation Research NetworkCalgaryABCanada
| | | | - Kevin Rioux
- Department of MedicineUniversity of CalgaryCalgaryABCanada
- Gastrointestinal Research GroupCalgaryABCanada
| | - Paul Beck
- Department of MedicineUniversity of CalgaryCalgaryABCanada
- Gastrointestinal Research GroupCalgaryABCanada
| | - Webb McKnight
- Department of MedicineMcMaster UniversityHamiltonONCanada
| | - Troy Feener
- Biological ScienceUniversity of CalgaryCalgaryABCanada
| | - John Wallace
- Department of MedicineMcMaster UniversityHamiltonONCanada
| | - Andre Buret
- Biological ScienceUniversity of CalgaryCalgaryABCanada
- Inflammation Research NetworkCalgaryABCanada
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Cotton J, Bhargava A, Ferraz J, Hollenberg M, Beck P, Buret A. A
Giardia
Cathepsin‐B‐like Protease Cleaves Interleukin‐8 From Intestinal Epithelial Cells. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.56.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- James Cotton
- Biological SciencesUniversity of CalgaryCalgaryABCanada
- Inflammation Research NetworkUniversity of CalgaryCalgaryABCanada
| | - Amol Bhargava
- Biological SciencesUniversity of CalgaryCalgaryABCanada
- Inflammation Research NetworkUniversity of CalgaryCalgaryABCanada
| | - Jose Ferraz
- Inflammation Research NetworkUniversity of CalgaryCalgaryABCanada
- MedicineUniversity of CalgaryCalgaryABCanada
| | - Morley Hollenberg
- Inflammation Research NetworkUniversity of CalgaryCalgaryABCanada
- Physiology and PharmacologyUniversity of CalgaryCalgaryABCanada
| | - Paul Beck
- MedicineUniversity of CalgaryCalgaryABCanada
- Gastrointestinal Research GroupUniversity of CalgaryCalgaryABCanada
| | - Andre Buret
- Biological SciencesUniversity of CalgaryCalgaryABCanada
- Inflammation Research NetworkUniversity of CalgaryCalgaryABCanada
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29
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Beatty J, Akierman S, Ceri H, Rioux K, Beck P, Buret A. Giardia duodenalis
: A model of pathogen‐mediated disruptions in the human microbiota in leading to the development of chronic gastrointestinal disease. FASEB J 2012. [DOI: 10.1096/fasebj.26.1_supplement.394.4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Jennifer Beatty
- University of CalgaryCalgaryABCanada
- Inflammation Research NetworkUniversity of CalgaryCalgaryABCanada
| | | | | | - Kevin Rioux
- MedicineUniversity of CalgaryCalgaryABCanada
- Gastrointestinal Research GroupUniversity of CalgaryCalgaryABCanada
| | - Paul Beck
- MedicineUniversity of CalgaryCalgaryABCanada
- Gastrointestinal Research GroupUniversity of CalgaryCalgaryABCanada
| | - Andre Buret
- University of CalgaryCalgaryABCanada
- Inflammation Research NetworkUniversity of CalgaryCalgaryABCanada
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Abstract
The findings discussed in the present research note report the extensive genotypic characterization of an intestinal epithelial cell line originally obtained from a human patient. Although the line exhibits karyotypic anomalies, with 76 modal chromosomes, its immunological, biochemical, and physiological phenotype make it a well-suited model to study intestinal epithelial processes, including those involved during intestinal parasitism. Polymerase chain reaction (PCR), isoenzyme analysis, and PCR gene product sequencing ultimately revealed that SCBN epithelial cells express a canine genotype. The observations held true for one of the early cell stocks obtained directly from the laboratory where the cell line was first isolated. Since no canine cells were used in that laboratory at that time, and in view of the normal canine modal chromosomal number of 78, the canine genotype of SCBN cells cannot be explained through simple laboratory contamination. The various characteristics of SCBN nonetheless make it a useful tool for research in epithelial biology, as well as in parasite-epithelial interactions. Its newly discovered genotypic characteristics are of significant relevance to researchers using this cell line.
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Affiliation(s)
- Andre Buret
- University of Calgary, Biological Sciences, 2500 University Dr. NW, Calgary, Alberta T2N 1N4, Canada.
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Abstract
BACKGROUND This study examined the effects of enterally administered epidermal growth factor (EGF) on nutrient absorption and tolerance of enteral feeds in pediatric patients with short bowel syndrome (SBS). METHODS Patients identified with severe SBS (<25% bowel length predicted for age) were prospectively enrolled in treatment using human recombinant EGF (1-53); 100 microg/kg per day given mixed with enteral feeds and patients were treated for 6 weeks. End points followed were patient weight, tolerance of enteral feeds, nutrient absorption, and intestinal permeability as determined using carbohydrate probes and hematologic values for liver function parameters. RESULTS Five patients were treated with EGF; all showed a significant improvement in carbohydrate absorption (3-0 methylglucose): absorption 24.7% +/- 9.7% pretreatment vs 34.1% +/- 13.8% posttreatment and improved tolerance of enteral feeds (enteral energy as % of total energy, 25% +/- 28% pretreatment vs 36% +/- 24% posttreatment; mean +/- SD; P < .05 by Wilcoxon's signed rank test). Epidermal growth factor treatment was not associated with significant changes in intestinal permeability, the rate of weight gain, or liver function tests. During the treatment phase, no patients developed episodes of sepsis; however, within 2 weeks of discontinuation of EGF treatment, 3 patients developed septic episodes. No adverse effects of EGF administration were noted. CONCLUSIONS These results suggest that enteral treatment with EGF in pediatric SBS improves nutrient absorption, increases tolerance with enteral feeds, and may improve the infection rate. Further studies exploring treatment strategies including the timing and duration of EGF administration are indicated.
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Affiliation(s)
- David L Sigalet
- GI Research Group, University of Calgary, Calgary, Alberta, Canada TZT SC7.
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32
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Ceri H, Olson M, Morck D, Storey D, Read R, Buret A, Olson B. The MBEC Assay System: multiple equivalent biofilms for antibiotic and biocide susceptibility testing. Methods Enzymol 2001; 337:377-85. [PMID: 11398443 DOI: 10.1016/s0076-6879(01)37026-x] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- H Ceri
- Biofilm Research Group, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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33
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Buresi MC, Schleihauf E, Vergnolle N, Buret A, Wallace JL, Hollenberg MD, MacNaughton WK. Protease-activated receptor-1 stimulates Ca(2+)-dependent Cl(-) secretion in human intestinal epithelial cells. Am J Physiol Gastrointest Liver Physiol 2001; 281:G323-32. [PMID: 11447011 DOI: 10.1152/ajpgi.2001.281.2.g323] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The thrombin receptor, protease-activated receptor-1 (PAR-1), has wide tissue distribution and is involved in many physiological functions. Because thrombin is in the intestinal lumen and mucosa during inflammation, we sought to determine PAR-1 expression and function in human intestinal epithelial cells. RT-PCR showed PAR-1 mRNA expression in SCBN cells, a nontransformed duodenal epithelial cell line. Confluent SCBN monolayers mounted in Ussing chambers responded to PAR-1 activation with a Cl(-)-dependent increase in short-circuit current. The secretory effect was blocked by BaCl2 and the Ca(2+)-ATPase inhibitor thapsigargin, but not by the L-type Ca(2+) channel blocker verapamil or DIDS, the nonselective inhibitor of Ca(2+)-dependent Cl(-) transport. Responses to thrombin and PAR-1-activating peptides exhibited auto- and crossdesensitization. Fura 2-loaded SCBN cells had increased fluorescence after PAR-1 activation, indicating increased intracellular Ca(2+). RT-PCR showed that SCBN cells expressed mRNA for the cystic fibrosis transmembrane conductance regulator (CFTR) and hypotonicity-activated Cl(-) channel-2 but not for the Ca(2+)-dependent Cl(-) channel-1. PAR-1 activation failed to increase intracellular cAMP, suggesting that the CFTR channel is not involved in the Cl(-) secretory response. Our data demonstrate that PAR-1 is expressed on human intestinal epithelial cells and regulates a novel Ca(2+)-dependent Cl(-) secretory pathway. This may be of clinical significance in inflammatory intestinal diseases with elevated thrombin levels.
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Affiliation(s)
- M C Buresi
- Mucosal Inflammation Research Group, University of Calgary, Calgary, Alberta, T2N 4N1, Canada
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34
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Ma L, Elliott SN, Cirino G, Buret A, Ignarro LJ, Wallace JL. Platelets modulate gastric ulcer healing: role of endostatin and vascular endothelial growth factor release. Proc Natl Acad Sci U S A 2001; 98:6470-5. [PMID: 11353854 PMCID: PMC33492 DOI: 10.1073/pnas.111150798] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Bleeding and delayed healing of ulcers are well recognized clinical problems associated with the use of aspirin and other nonsteroidal antiinflammatory drugs, which have been attributed to their antiaggregatory effects on platelets. We hypothesized that antiplatelet drugs might interfere with gastric ulcer healing by suppressing the release of growth factors, such as vascular endothelial growth factor (VEGF), from platelets. Gastric ulcers were induced in rats by serosal application of acetic acid. Daily oral treatment with vehicle, aspirin, or ticlopidine (an ADP receptor antagonist) was started 3 days later and continued for 1 week. Ulcer induction resulted in a significant increase in serum levels of VEGF and a significant decrease in serum levels of endostatin (an antiangiogenic factor). Although both aspirin and ticlopidine markedly suppressed platelet aggregation, only ticlopidine impaired gastric ulcer healing and angiogenesis as well as reversing the ulcer-associated changes in serum levels of VEGF and endostatin. The effects of ticlopidine on ulcer healing and angiogenesis were mimicked by immunodepletion of circulating platelets, and ticlopidine did not influence ulcer healing when given to thrombocytopenic rats. Incubation of human umbilical vein endothelial cells with serum from ticlopidine-treated rats significantly reduced proliferation and increased apoptosis, effects reversed by an antibody directed against endostatin. Ticlopidine treatment resulted in increased platelet endostatin content and release. These results demonstrate a previously unrecognized contribution of platelets to the regulation of gastric ulcer healing. Such effects likely are mediated through the release from platelets of endostatin and possibly VEGF. As shown with ticlopidine, drugs that influence gastric ulcer healing may do so in part through altering the ability of platelets to release growth factors.
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Affiliation(s)
- L Ma
- Mucosal Inflammation Research Group, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, T2N 4N1, Canada
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35
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Goubau S, Morck DW, Buret A. Tilmicosin does not inhibit interleukin-8 gene expression in the bovine lung experimentally infected with Mannheimia (Pasteurella) haemolytica. Can J Vet Res 2000; 64:238-42. [PMID: 11041503 PMCID: PMC1189625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
The expression of the interleukin-8 (IL-8) gene was examined by in situ hybridization in lung tissues from calves experimentally infected with Mannheimia (Pasteurella) haemolytica and treated with tilmicosin. Interleukin-8 mRNA expression was detected in alveolar areas, particularly along interlobular septa, in the lumen, and in the epithelial cells of some bronchioles. In lesional lung tissues from animals that had received tilmicosin, we found large areas with limited inflammation. There was no staining for IL-8 mRNA in these areas. In contrast, in strongly inflamed areas, the same patterns and intensities of staining for IL-8 mRNA were detected in tilmicosin- and sham-treated animals. We conclude that tilmicosin does not affect the expression of IL-8 mRNA in tissue showing microscopic signs of inflammation. Together with previous reports, this supports the view that the pro-apoptotic properties of tilmicosin on neutrophils do not compromise the host defense mechanisms required to control the infection.
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Affiliation(s)
- S Goubau
- Department of Biological Sciences, University of Calgary, Alberta
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36
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Elliott SN, Wallace JL, McKnight W, Gall DG, Hardin JA, Olson M, Buret A. Bacterial colonization and healing of gastric ulcers: the effects of epidermal growth factor. Am J Physiol Gastrointest Liver Physiol 2000; 278:G105-12. [PMID: 10644568 DOI: 10.1152/ajpgi.2000.278.1.g105] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Experimental gastric ulcers are rapidly colonized by various bacteria, resulting in significantly impaired healing. Epidermal growth factor (EGF) is capable of preventing bacterial colonization of the healthy intestinal mucosa. In this study, we examined the possibility that EGF accelerates gastric ulcer healing by reducing bacterial colonization of the ulcer. Gastric ulcers were induced by serosal application of acetic acid. The effect of daily administration of EGF on ulcer healing and bacterial colonization was assessed and compared with the effect of daily treatment with broad-spectrum antibiotics. EGF administration reduced colonization levels and accelerated ulcer healing as effectively as the antibiotic treatment. EGF was without effect on acid secretion or neutrophil infiltration into the ulcer. Bacterial growth was not inhibited in the presence of EGF in vitro. These results demonstrate that EGF reduces bacterial colonization during an established infection of a compromised mucosal surface. This effect may contribute to the ability of EGF to accelerate gastric ulcer healing. This effect is acid independent and not due to an anti-inflammatory effect or to direct bactericidal actions.
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Affiliation(s)
- S N Elliott
- Department, University of Calgary, Calgary, Alberta, Canada T2N 1N4
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37
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Abstract
The epidermal growth factor receptor (EGFr) is a transmembrane glycoprotein with an intrinsic tyrosine kinase. Ligand-binding to the EGFr activates cell signaling, phosphorylates protein kinases, and rearranges cytoskeletal proteins - responses that resemble those induced by microbial attachment to cell surfaces, a process known to be mediated by host cell receptors in a number of cases. This article critically reviews the possible role played by the EGFr in microbial colonization, and discusses how modulation of the EGF-EGFr axis may affect infection of the gastrointestinal tract.
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Affiliation(s)
- A Buret
- Department of Biological Sciences, University of Calgary, Alberta, Canada
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38
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Ceri H, Olson ME, Stremick C, Read RR, Morck D, Buret A. The Calgary Biofilm Device: new technology for rapid determination of antibiotic susceptibilities of bacterial biofilms. J Clin Microbiol 1999; 37:1771-6. [PMID: 10325322 PMCID: PMC84946 DOI: 10.1128/jcm.37.6.1771-1776.1999] [Citation(s) in RCA: 1375] [Impact Index Per Article: 55.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Determination of the MIC, based on the activities of antibiotics against planktonic bacteria, is the standard assay for antibiotic susceptibility testing. Adherent bacterial populations (biofilms) present with an innate lack of antibiotic susceptibility not seen in the same bacteria grown as planktonic populations. The Calgary Biofilm Device (CBD) is described as a new technology for the rapid and reproducible assay of biofilm susceptibilities to antibiotics. The CBD produces 96 equivalent biofilms for the assay of antibiotic susceptibilities by the standard 96-well technology. Biofilm formation was followed by quantitative microbiology and scanning electron microscopy. Susceptibility to a standard group of antibiotics was determined for National Committee for Clinical Laboratory Standards (NCCLS) reference strains: Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and Staphylococcus aureus ATCC 29213. Growth curves demonstrated that biofilms of a predetermined size could be formed on the CBD at specific time points and, furthermore, that no significant difference (P > 0.1) was seen between biofilms formed on each of the 96 pegs. The antibiotic susceptibilities for planktonic populations obtained by the NCCLS method or from the CBD were similar. Minimal biofilm eradication concentrations, derived by using the CBD, demonstrated that for biofilms of the same organisms, 100 to 1,000 times the concentration of a certain antibiotic were often required for the antibiotic to be effective, while other antibiotics were found to be effective at the MICs. The CBD offers a new technology for the rational selection of antibiotics effective against microbial biofilms and for the screening of new effective antibiotic compounds.
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Affiliation(s)
- H Ceri
- Biofilm Research Group, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
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39
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Buret A, Olson ME, Gall DG, Hardin JA. Effects of orally administered epidermal growth factor on enteropathogenic Escherichia coli infection in rabbits. Infect Immun 1998; 66:4917-23. [PMID: 9746597 PMCID: PMC108608 DOI: 10.1128/iai.66.10.4917-4923.1998] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The increased intestinal absorption induced by epidermal growth factor (EGF) is associated with diffuse lengthening of brush border microvilli. The aim of this study was to examine the in vivo effects of oral administration of EGF during infection with enteropathogenic Escherichia coli. New Zealand White rabbits (4 weeks old) received orogastric EGF daily starting 3 days prior to infection with enteropathogenic E. coli RDEC-1 and were compared with sham-treated infected animals and uninfected controls. Weight gain, food intake, fecal E. coli, and stool consistency were assessed daily. On day 10, segments of jejunum, ileum, proximal, and distal colon were assessed for gram-negative bacterial colonization, disaccharidase activities, and epithelial ultrastructure. Effects of EGF on E. coli RDEC-1 proliferation were studied in vitro. E. coli RDEC-1 caused diarrhea and reduced weight gain. Seven days postinfection, the small and large intestines were colonized with numerous bacteria, brush border microvilli were disrupted, and maltase and sucrase activities were significantly reduced in the jejunum. Daily treatment with EGF prevented the occurrence of diarrhea and reduction of weight gain. These effects were associated with significant inhibition of E. coli colonization in the small and large intestine, improved jejunal maltase and sucrase activities and reduced microvillous injury. EGF did not affect the proliferation of E. coli in vitro. The findings suggest that EGF protects the gastrointestinal tract against colonization by enteropathogenic E. coli.
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Affiliation(s)
- A Buret
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada T2N 1N4.
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40
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Abstract
The stomach is generally regarded as an environment that is not conducive to bacterial colonization. In this study, we examined the possibility that this changes significantly when an ulcer has formed and that colonization of ulcers interferes with the normal healing process. Gastric ulcers were induced by serosal application of acetic acid. The relationship between ulcer healing and bacterial colonization was examined. The effects of antibiotics, induction of Lactobacillus colonization, and selective colonization with an antibiotic resistant strain of Escherichia coli on ulcer healing were examined. Within 6-12 h of their induction, gastric ulcers were colonized by a variety of bacteria, with gram-negative bacteria predominating. Suppression of colonization with antibiotics resulted in marked acceleration of healing. Induction of Lactobacillus colonization also accelerated ulcer healing. The beneficial effects of antibiotics were reversed through selective colonization with antibiotic-resistant E. coli. Bacterial colonization occurred irrespective of the method used to induce the ulcer. This study demonstrates that colonization of gastric ulcers in rats occurs rapidly and significantly impairs ulcer healing. This effect appeared to be primarily attributable to gram-negative bacteria.
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Affiliation(s)
- S N Elliott
- Department of Pharmacology and Therapeutics, University of Calgary, Calgary, Alberta, Canada T2N 4N1
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41
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O'Loughlin EV, Zhe L, Buret A, Bell C, Robins-Browne RM, Elliott EJ. Colonic structural and ion transport abnormalities in suckling rabbits infected with Escherichia coli K12. J Pediatr Gastroenterol Nutr 1997; 25:394-9. [PMID: 9327369 DOI: 10.1097/00005176-199710000-00006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Escherichia coli K12 is a laboratory strain considered nonpathogenic. The purpose of this study was to examine the effect of E. coli K12 infection on colonic structure and function. METHODS Suckling rabbits were infected at 10 days of age with 6 x 10(9) CFU E. coli by intragastric inoculation and were examined 4 to 5 days later. Segments of ileum and proximal and distal colon were removed for light and electron microscopy, and NaCl transport was examined in vitro under short-circuited conditions in Ussing chambers. RESULTS Infection did not cause weight loss or diarrhea. Colonic mucosa was inflamed with infiltration by polymorphonuclear neutrophils mainly in the lamina propria. The proximal and distal colon exhibited reduced Na+ absorption. The proximal colon also showed increased Cl- secretion; the ileum was unaffected. CONCLUSIONS Infection with E. coli K12 disrupts the epithelium and alters ion transport in the colon, probably as a result of mucosal inflammation. The changes indicate that nonpathogenic E. coli have the potential to cause intestinal disease.
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Affiliation(s)
- E V O'Loughlin
- Department of Gastroenterology, Royal Alexandra Hospital for Children, Westmead, New South Wales, Australia
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42
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Sparrow DG, Gard S, Buret A, Ceri H, Olson M, Morck DW. Expression of tumor necrosis factor alpha and granulocyte-macrophage colony-stimulating factor by bovine endothelial cells in vitro. Clin Infect Dis 1997; 25 Suppl 2:S178-9. [PMID: 9310669 DOI: 10.1086/516182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- D G Sparrow
- Department of Biological Sciences, University of Calgary, Alberta, Canada
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43
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Lincz LF, Buret A, Burns GF. Formation of spheroid structures in a human colon carcinoma cell line involves a complex series of intercellular rearrangements. Differentiation 1997; 61:261-74. [PMID: 9203349 DOI: 10.1046/j.1432-0436.1997.6140261.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The structural remodelling of tissues that occurs in vivo during animal morphogenesis can often prove difficult to study. Here we investigate the organizational processes of the LIM 1863 colon carcinoma cell line as it transforms from a single-cell stage into multicellular spherical structures called 'organoids'. The organoids can be dissociated into a viable single-cell suspension when cultured in calcium-depleted medium, and then induced to reform the organoid structure by the readdition of calcium. Previous studies have shown that initial cell attachment under these conditions is characterized by a novel mechanism of cell engulfment termed 'clutching'. This investigation reveals the subsequent appearance of junctional complexes between groups of 'clutched' cells prior to lumen formation, and the ultimate 'declutching' of entrapped cells as a means of cell rearrangement. Intact actin filaments but not microtubules were required for the initial clutching events, while inhibition of microtubule polymerization resulted in aberrant apical protein polarization, but did not affect the development of a luminal space within the spheroids. Single cells exhibited pools of intracellular microvilli contained in vacuolar apical compartments, which were resistant to the effects of cytoskeleton-disrupting drugs. However, these structures did not seem to be responsible for the swift development of the luminal surface observed in these cells. Two other cell lines, MDCK and DU 4475, were found to exhibit similar clutching conformations when induced to form three-dimensional structures, suggesting that this may be a widespread mechanism of cell rearrangement that reflects the process of organ morphogenesis in vivo.
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Affiliation(s)
- L F Lincz
- Cancer Research Unit, Faculty of Medicine, University of Newcastle, NSW 2308, Australia
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44
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Abstract
Using a new animal model, the aims of this study were to assess the role played by purified lipopolysaccharide (LPS) and neutrophils in the pathogenesis of acute red-eye reactions (ARE) and corneal ulcers. In addition, IL-1 alpha was assessed for its implications in the formation of corneal ulcers. Following corneal abrasion, eyes of rabbits underwent single or double exposures to various doses of LPS from Pseudomonas aeruginosa or Serratia marcescens. This protocol induced ARE symptoms, and their severity depended on the dosage, number of LPS exposures, and type of LPS used (LPS from S. marcescens showing highest virulence). Corneal ulcers were induced by delivering a high dose of Serratia LPS (100 micrograms) followed by a low dose (10 micrograms). Histopathological examination revealed that both ARE and corneal ulceration were associated with prominent neutrophil infiltration. In addition, many lymphocytes and other monocytic cells infiltrated ulcerated ocular tissue. Tear fluids obtained from ulcerated eyes contained high concentrations of a protein recognized by anti-rabbit IL-1 alpha antibodies as demonstrated by immunoblotting studies. The results indicate that LPS can induce ARE and corneal ulceration in the absence of any live bacteria. Moreover, the findings implicate the accumulation of neutrophils and IL-1 alpha-related proteins in the pathogenesis of ARE and corneal ulcers.
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Affiliation(s)
- C L Schultz
- Department of New Product Research, Vistakon, Jacksonville, Florida 32247, USA
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Reuter BK, Asfaha S, Buret A, Sharkey KA, Wallace JL. Exacerbation of inflammation-associated colonic injury in rat through inhibition of cyclooxygenase-2. J Clin Invest 1996; 98:2076-85. [PMID: 8903327 PMCID: PMC507652 DOI: 10.1172/jci119013] [Citation(s) in RCA: 311] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Cyclooxygenase type 1 is constitutively expressed and accounts for synthesis of prostaglandins in the normal gastrointestinal tract. Cyclooxygenase-2 is expressed at sites of inflammation. Selective inhibitors of cyclooxygenase-2 have been suggested to spare gastrointestinal prostaglandin synthesis, and therefore lack the ulcerogenic effects associated with standard nonsteroidal antiinflammatory drugs. However, the effects of cyclooxygenase-2 inhibitors on inflamed gastrointestinal mucosa have not been examined. We examined cyclooxygenase-2 mRNA and protein expression before and after induction of colitis in the rat, the contribution of cyclooxygenase-2 to colonic prostaglandin synthesis during colitis and the effects of selective inhibitors of cyclooxygenase-2 on colonic injury in this model. Cyclooxygenase-2 mRNA expression increased three to sixfold during the period 24 h to 1 wk after induction of colitis, with marked increases in cyclooxygenase-2 protein expression in the lamina propria and muscularis of the colon during colitis. Cyclooxygenase-1 expression (mRNA and protein) was not affected by the induction of colitis. The prostaglandins produced during colitis were largely derived from cyclooxygenase-2. Treatment with selective cyclooxygenase-2 inhibitors resulted in exacerbation of colitis, with perforation occurring when the compounds were administered for a week. These studies demonstrate that suppression of cyclooxygenase-2 can result in exacerbation of inflammation-associated colonic injury.
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Affiliation(s)
- B K Reuter
- Department of Pharmacology and Therapeutics, University of Calgary, Alberta, Canada
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Pang G, Buret A, O'Loughlin E, Smith A, Batey R, Clancy R. Immunologic, functional, and morphological characterization of three new human small intestinal epithelial cell lines. Gastroenterology 1996; 111:8-18. [PMID: 8698229 DOI: 10.1053/gast.1996.v111.pm8698229] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND & AIMS Epithelial cell cultures can be used for the study of epithelial cell biology, although human small intestinal cultures have not been available to date. The aim of this study was to characterize three cell lines derived from normal human duodenum. METHODS Cells were cultured from tissue fragments obtained from endoscopic biopsy specimens and characterized with respect to morphology and cytokine gene expression and for the presence of vectorial transport. RESULTS All cell lines grew as polarized continuous monolayers and were mostly cuboidal in shape but were not immortalized. Cells showed junctional complexes and sparse microvilli. All cell lines showed cytokeratins and mucin antigen but not chromagranin and messenger RNA for epidermal growth factor, interleukin 6, and vascular cell adhesion molecule 1. Disaccharidase activities were low and correlated with the low proportion of cells (1%-10%), showing positive immunocytochemistry for sucrase. Monolayer resistance varied from 30 to 200 ohms. One monolayer (BN) consistently showed secretion in response to forskolin (10 micromol/L), which could b inhibited by chloride-free buffer and apical addition of the chloride channel blocker diphenylamine decarboxylate. No monolayer had evidence of glucose transport. CONCLUSIONS These three nonimmortalized lines show morphological, phenotypic, and transport characteristics of crypt-like intestinal epithelial cells. The pattern of messenger RNA expression suggests a growth-promoting and immunomodulatory role.
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Affiliation(s)
- G Pang
- Faculty of Medicine and Australian Institute of Mucosal Immunology, University of Newcastle, New South Wales, Australia
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Wilson NR, Dunkley ML, Buret A, Young B, Cripps AW. Histopathology of the lung following intratracheal challenge with live Pseudomonas aeruginosa in intestinally immunized rats. Immunol Cell Biol 1995; 73:440-5. [PMID: 8595922 DOI: 10.1038/icb.1995.68] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
This paper examines the histology of rat lungs following intestinal immunization with killed mucoid Pseudomonas aeruginosa and subsequent pulmonary challenge with live P. aeruginosa. The lungs of non-immune challenged rats developed a confluent haemorrhagic pneumonitis with degeneration and sloughing of the mucosa of the airways; perivascular infiltration with mononuclear cells was apparent 1-2 h post-challenge; some neutrophils were present by 2 h post-challenge; by 12 h post-challenge oedema and intra-alveolar haemorrhage were prominent and Gram-negative organisms were seen in large quantities. In contrast, immunized challenged animals showed a pronounced neutrophilic response 1-2 h post challenge; by 12 h post-challenge patchy abscesses were apparent with resolving inflammation and no organisms visible. The findings suggest that intestinal immunization prevents the development of fatal P. aeruginosa infections in the lung by accelerating the recruitment of polymorphonuclear neutrophils.
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Affiliation(s)
- N R Wilson
- Department of Anatomical Pathology, Hunter Area Pathology, Service, NSW, Australia
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Buret A, Dunkley ML, Pang G, Clancy RL, Cripps AW. Pulmonary immunity to Pseudomonas aeruginosa in intestinally immunized rats roles of alveolar macrophages, tumor necrosis factor alpha, and interleukin-1 alpha. Infect Immun 1994; 62:5335-43. [PMID: 7960112 PMCID: PMC303273 DOI: 10.1128/iai.62.12.5335-5343.1994] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The aims of this study were to assess the role played by alveolar macrophages, tumor necrosis factor alpha (TNF-alpha), and interleukin-1 alpha (IL-1 alpha) in pulmonary immunity against Pseudomonas aeruginosa in animals that have been immunized via the gut-associated lymphoid tissue. Following intra-Peyer's patch immunization and subsequent intratracheal challenge with live bacteria, significantly enhanced bacterial clearance from the lungs correlated with an increase in bronchoalveolar neutrophils, increased recruitment and phagocytic activity of alveolar macrophages, and accelerated production of TNF-alpha in the bronchoalveolar space, while levels of IL-1 alpha remained low. Administration of recombinant TNF-alpha in physiological concentrations did not affect the proliferation of P. aeruginosa in vitro, but when given intratracheally to rats at the time of infection, recombinant TNF-alpha significantly increased bacterial clearance from the lungs. In these animals, phagocytic activity of bronchoalveolar neutrophils was enhanced, while the recruitment of alveolar macrophages and neutrophils remained unchanged. In acutely infected nonimmune animals, bronchoalveolar concentrations of soluble IL-1 alpha and TNF-alpha increased until the time of death. Levels of prostaglandin E2 and thromboxane B2 were similar in each experimental group. These results indicate that infection in immune animals enhanced both recruitment and phagocytic activity of alveolar macrophages as well as induced an accelerated production of TNF-alpha. In immune challenged animals, this cytokine enhanced the phagocytic activity of neutrophils and improved bacterial clearance from the lung. Levels of soluble IL-1 alpha and TNF-alpha in nonimmune rats increased consistently following infection until the time of death, thus implicating these cytokines in the pathogenesis of acute P. aeruginosa pneumonia.
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Affiliation(s)
- A Buret
- Australian Institute of Mucosal Immunology, Faculty of Medicine, University of Newcastle, Royal Newcastle Hospital, New South Wales, Australia
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Elliott E, Li Z, Bell C, Stiel D, Buret A, Wallace J, Brzuszczak I, O'Loughlin E. Modulation of host response to Escherichia coli o157:H7 infection by anti-CD18 antibody in rabbits. Gastroenterology 1994; 106:1554-61. [PMID: 7910802 DOI: 10.1016/0016-5085(94)90410-3] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND/AIMS Escherichia coli O157:H7 infection induces diarrhea, severe colitis, and colonic electrolyte transport abnormalities characterized by decreased Na absorption and Cl secretion. The aim of this study was to examine the role of the host inflammatory response in inducing distal colonic transport changes during infection with E. coli O157:H7. METHODS New Zealand white rabbits aged 10 days were infected with E. coli O157:H7 strain EDL933 (plasmid+, verotoxin 1+, verotoxin 2+). Studies were performed daily from day 1 to day 5 postinfection and compared with uninfected controls (10 days old). Distal colonic ion transport was studied in vitro under short-circuited conditions in Ussing chambers, and tissue inflammation was assessed by mucosal myeloperoxidase activities and mucosal neutrophil (polymorphonuclear neutrophil [PMN]) counts. In a second study, PMN infiltration was inhibited by an anti-CD18 (leukocyte adhesion molecule) monoclonal antibody, IB4, and histology and transport were studied on day 5 postinfection. RESULTS Infection with O157:H7 induced diarrhea and inhibition of Na absorption by day 3. CI secretion occurred on day 5, coincident with tissue infiltration with PMN. Pretreatment with IB4 prevented histological damage and tissue infiltration with PMN, and it inhibited the transport abnormalities induced by infection alone. CONCLUSIONS Infection with O157:H7 reduces Na absorption and stimulates Cl secretion in the distal colon. Disruption of the epithelium and changes in colonic electrolyte transport during enterohemorrhagic E. coli are mediated by the host inflammatory response.
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Affiliation(s)
- E Elliott
- Department of Pediatrics and Child Health, Children's Hospital, Camperdown, Australia
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Abstract
The LIM 1863 colon carcinoma cell line grows as structural organoids of goblet and columnar cells around a central lumen and provides a model for the development of stem cells in the normal colon. The organoid structure can be disrupted by removal of calcium from the medium, resulting in a suspension of single cells. Upon readdition of calcium, the cells reform the organoid structure over a period of 24 h, and ultrastructural examination of the reforming cells reveals that this involves a complex process that we have termed clutching. To determine the adhesion molecules involved in organoid formation we attempted to block this process by single cell suspensions of LIM 1863 reseeded in the presence of monoclonal antibodies. An anti-integrin antibody directed against a conformational epitope on the alpha v subunit totally inhibited organoid reformation. As a consequence of this inhibition of cell contact the colon carcinoma cells rapidly underwent apoptosis. Investigations of the apoptotic pathway involved suggested an induction mechanism since the onset of apoptosis in the contact-inhibited cells showed specific increased synthesis of 68- and 72-kD proteins. In addition, immunoblotting of cytosolic and nuclear extracts of the cells revealed the rapid translocation of the tumor suppressor gene product, p53 to the cell nucleus upon induction of apoptosis. These results suggest that cell-cell adhesion may be a vital regulator of colon development overcome in tumor cells by loss of adhesion molecules or of functional p53 protein.
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Affiliation(s)
- R C Bates
- Cancer Research Unit, Faculty of Medicine, University of Newcastle, New South Wales, Australia
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