1
|
Application of OU processes to modelling temporal dynamics of the human microbiome, and calculating optimal sampling schemes. BMC Bioinformatics 2020; 21:450. [PMID: 33045987 PMCID: PMC7549249 DOI: 10.1186/s12859-020-03747-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 09/11/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The vast majority of microbiome research so far has focused on the structure of the microbiome at a single time-point. There have been several studies that measure the microbiome from a particular environment over time. A few models have been developed by extending time series models to accomodate specific features in microbiome data to address questions of stability and interactions of the microbime time series. Most research has observed the stability and mean reversion for some microbiomes. However, little has been done to study the mean reversion rates of these stable microbes and how sampling frequencies are related to such conclusions. In this paper, we begin to rectify this situation. We analyse two widely studied microbial time series data sets on four healthy individuals. We choose to study healthy individuals because we are interested in the baseline temporal dynamics of the microbiome. RESULTS For this analysis, we focus on the temporal dynamics of individual genera, absorbing all interactions in a stochastic term. We use a simple stochastic differential equation model to assess the following three questions. (1) Does the microbiome exhibit temporal continuity? (2) Does the microbiome have a stable state? (3) To better understand the temporal dynamics, how frequently should data be sampled in future studies? We find that a simple Ornstein-Uhlenbeck model which incorporates both temporal continuity and reversion to a stable state fits the data for almost every genus better than a Brownian motion model that contains only temporal continuity. The Ornstein-Uhlenbeck model also fits the data better than modelling separate time points as independent. Under the Ornstein-Uhlenbeck model, we calculate the variance of the estimated mean reversion rate (the speed with which each genus returns to its stable state). Based on this calculation, we are able to determine the optimal sample schemes for studying temporal dynamics. CONCLUSIONS There is evidence of temporal continuity for most genera; there is clear evidence of a stable state; and the optimal sampling frequency for studying temporal dynamics is in the range of one sample every 0.8-3.2 days.
Collapse
|
2
|
Park SH, Moon Y. Enterocyte-Based Bioassay via Quantitative Combination of Proinflammatory Sentinels Specific to 8-keto-trichothecenes. Front Immunol 2020; 11:1530. [PMID: 32765531 PMCID: PMC7378738 DOI: 10.3389/fimmu.2020.01530] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 06/10/2020] [Indexed: 12/12/2022] Open
Abstract
Type B 8-keto-trichothecenes are muco-active mycotoxins that exist as inevitable contaminants in cereal-based foodstuffs. Gut-associated inflammation is an early frontline response during human and animal exposure to these mycotoxins. Despite various tools for chemical identification, optimized biomonitoring of sentinel response-associated biomarkers is required to assess the specific proinflammatory actions of 8-keto-trichothecenes in the gut epithelial barrier. In the present study, intoxication with 8-keto-trichothecenes in human intestinal epithelial cells was found to trigger early response gene 1 product (EGR-1) that plays crucial roles in proinflammatory chemokine induction. In contrast, epithelial exposure to 8-keto-trichothecenes resulted in downregulated expression of nuclear factor NF-kappa-B p65 protein, a key transcription factor, during general inflammatory responses in the gut. Based on the early molecular patterns of expression, the inflammation-inducing activity of 8-keto-trichothecenes was quantified using intestinal epithelial cells with dual reporters for EGR-1 and p65 proteins. EGR-1-responsive elements were linked to luciferase reporter while p65 promoter was bound to secretory alkaline phosphatase (SEAP) reporter. In response to conventional inflammagens such as endotoxins and cytokines such as TNF-α, both luciferase and SEAP activity were elevated in a dose-dependent manner. However, as expected from the mechanistic evaluation, 8-keto-trichothecene-exposed dual reporters of luciferase and SEAP displayed contrasting expression patterns. Furthermore, 8-keto-trichothecene-elevated EGR-1-responsive luciferase activity was improved by deficiency of PSMA3, an α-type subunit of the 20S proteasome core complex for ubiquitin-dependent EGR-1 degradation. This molecular event-based dual biomonitoring in epithelial cells is a promising supplementary tool for detecting typical molecular inflammatory pathways in response to 8-keto-trichothecenes in the food matrix.
Collapse
Affiliation(s)
- Seong-Hwan Park
- Laboratory of Mucosal Exposome and Biomodulation, Department of Biomedical Sciences, Pusan National University, Yangsan, South Korea
| | - Yuseok Moon
- Laboratory of Mucosal Exposome and Biomodulation, Department of Biomedical Sciences, Pusan National University, Yangsan, South Korea.,Biomedical Research Institute, Pusan National University, Yangsan, South Korea
| |
Collapse
|
3
|
Li JH, Evans JD, Li WF, Zhao YZ, DeGrandi-Hoffman G, Huang SK, Li ZG, Hamilton M, Chen YP. New evidence showing that the destruction of gut bacteria by antibiotic treatment could increase the honey bee's vulnerability to Nosema infection. PLoS One 2017; 12:e0187505. [PMID: 29125851 PMCID: PMC5681286 DOI: 10.1371/journal.pone.0187505] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 10/20/2017] [Indexed: 12/19/2022] Open
Abstract
It has become increasingly clear that gut bacteria play vital roles in the development, nutrition, immunity, and overall fitness of their eukaryotic hosts. We conducted the present study to investigate the effects of gut microbiota disruption on the honey bee's immune responses to infection by the microsporidian parasite Nosema ceranae. Newly emerged adult workers were collected and divided into four groups: Group I-no treatment; Group II-inoculated with N. ceranae, Group III-antibiotic treatment, and Group IV-antibiotic treatment after inoculation with N. ceranae. Our study showed that Nosema infection did not cause obvious disruption of the gut bacterial community as there was no significant difference in the density and composition of gut bacteria between Group I and Group II. However, the elimination of gut bacteria by antibiotic (Groups III and IV) negatively impacted the functioning of the honey bees' immune system as evidenced by the expression of genes encoding antimicrobial peptides abaecin, defensin1, and hymenoptaecin that showed the following ranking: Group I > Group II > Group III > Group IV. In addition, significantly higher Nosema levels were observed in Group IV than in Group II, suggesting that eliminating gut bacteria weakened immune function and made honey bees more susceptible to Nosema infection. Based on Group IV having displayed the highest mortality rate among the four experimental groups indicates that antibiotic treatment in combination with stress, associated with Nosema infection, significantly and negatively impacts honey bee survival. The present study adds new evidence that antibiotic treatment not only leads to the complex problem of antibiotic resistance but can impact honey bee disease resistance. Further studies aimed at specific components of the gut bacterial community will provide new insights into the roles of specific bacteria and possibly new approaches to improving bee health.
Collapse
Affiliation(s)
- Jiang Hong Li
- USDA-ARS Bee research Laboratory, Beltsville, MD, United States of America
- College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jay D. Evans
- USDA-ARS Bee research Laboratory, Beltsville, MD, United States of America
| | - Wen Feng Li
- USDA-ARS Bee research Laboratory, Beltsville, MD, United States of America
| | - Ya Zhou Zhao
- Institute of Apicultural Research, Chinese Academy of Agriculture Sciences, Beijing, China
| | | | - Shao Kang Huang
- College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Zhi Guo Li
- College of Bee Science, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Michele Hamilton
- USDA-ARS Bee research Laboratory, Beltsville, MD, United States of America
| | - Yan Ping Chen
- USDA-ARS Bee research Laboratory, Beltsville, MD, United States of America
- * E-mail:
| |
Collapse
|
4
|
The Role of Malnutrition during Pregnancy and Its Effects on Brain and Skeletal Muscle Postnatal Development. J Funct Morphol Kinesiol 2017. [DOI: 10.3390/jfmk2030030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
“Foetal programming” refers to nutritional and hormonal variations during pregnancy. A maternal proper diet has a fundamental role in decreasing pregnancy complications and to prevent possible diseases in postnatal life. In our narrative review, we analyze and discuss the role of malnutrition during pregnancy and its effects on pre- and postnatal development of embryos. Our review proposes a comprehensive and careful analysis of the studies in this field regarding malnutrition and foetal programming. Evidence shows that nutrient imbalance before implantation may result in somatic hypoevolutism at birth, and endocrine and metabolic dysfunctions in postnatal life. In addition, the maternal malnutrition could exert a suppressive effect on the maternal and foetal immune response. It could also affect both the proliferation of myogenic precursors reducing the number of muscle fibres and the future reproductive maturation with possible consequent impaired fertility and quality of gametes. In conclusion, it is necessary to develop dietary strategies to optimize nutrition, not only during pregnancy but already when it is programmed, in order to improve the outcomes of pregnancy, promote growth, healthy child development, reduce the risk of chronic diseases, and slow down the metabolic decline associated with aging.
Collapse
|
5
|
Abreu MT, Thomas LS, Arnold ET, Lukasek K, Michelsen KS, Arditi M. TLR signaling at the intestinal epithelial interface. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519030090050901] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The intestinal epithelium provides a critical interface between lumenal bacteria and the mucosal immune system. Whereas normal commensal flora do not trigger acute inflammation, pathogenic bacteria trigger a potent inflammatory response. Our studies emanate from the hypothesis that the intestinal epithelium is normally hyporesponsive to commensal pathogen-associated molecular patterns (PAMPs) such as LPS. Our data demonstrate that normal human colonic epithelial cells and lamina propria cells express low levels of TLR4 and its co-receptor MD-2. This expression pattern is mirrored by intestinal epithelial cell (IEC) lines. Co-expression of TLR4 and MD-2 is necessary and sufficient for LPS responsiveness in IEC. Moreover, LPS sensing occurs along the basolateral membrane of polarized IEC in culture. Expression of MD-2 is regulated by IFN-γ. Cloning of the MD-2 promoter demonstrates that promoter activity is increased by IFN-γ and blocked by the STAT inhibitor SOCS3. We conclude from our studies that the intestinal epithelium down-regulates expression of TLR4 and MD-2 and is LPS unresponsive. The Th1 cytokine IFN-γ up-regulates expression of MD-2 in a STAT-dependent fashion. The results of our studies have important implications for understanding human inflammatory bowel diseases.
Collapse
Affiliation(s)
- Maria T. Abreu
- Inflammatory Bowel Disease Center, Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA,
| | - Lisa S. Thomas
- Inflammatory Bowel Disease Center, Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Elizabeth T. Arnold
- Inflammatory Bowel Disease Center, Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Katie Lukasek
- Inflammatory Bowel Disease Center, Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Kathrin S. Michelsen
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Steven Spielberg Pediatric Research Center, Burns and Allen Research Institute
| | - Moshe Arditi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Steven Spielberg Pediatric Research Center, Burns and Allen Research Institute
| |
Collapse
|
6
|
Koutsounas I, Kaltsa G, Siakavellas SI, Bamias G. Markers of bacterial translocation in end-stage liver disease. World J Hepatol 2015; 7:2264-2273. [PMID: 26380651 PMCID: PMC4568487 DOI: 10.4254/wjh.v7.i20.2264] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/13/2015] [Accepted: 08/31/2015] [Indexed: 02/06/2023] Open
Abstract
Bacterial translocation (BT) refers to the passage of viable bacteria or bacterial products from the intestinal lumen, through the intestinal epithelium, into the systemic circulation and extraintestinal locations. The three principal mechanisms that are thought to be involved in BT include bacterial overgrowth, disruption of the gut mucosal barrier and an impaired host defence. BT is commonly observed in liver cirrhosis and has been shown to play an important role in the pathogenesis of the complications of end stage liver disease, including infections as well as hepatic encephalopathy and hepatorenal syndrome. Due to the importance of BT in the natural history of cirrhosis, there is intense interest for the discovery of biomarkers of BT. To date, several such candidates have been proposed, which include bacterial DNA, soluble CD14, lipopolysaccharides endotoxin, lipopolysaccharide-binding protein, calprotectin and procalcitonin. Studies on the association of these markers with BT have demonstrated not only promising data but, oftentimes, contradictory results. As a consequence, currently, there is no optimal marker that may be used in clinical practice as a surrogate for the presence of BT.
Collapse
|
7
|
Young JC, Pan C, Adams RM, Brooks B, Banfield JF, Morowitz MJ, Hettich RL. Metaproteomics reveals functional shifts in microbial and human proteins during a preterm infant gut colonization case. Proteomics 2015; 15:3463-73. [PMID: 26077811 DOI: 10.1002/pmic.201400563] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 05/27/2015] [Accepted: 06/11/2015] [Indexed: 01/01/2023]
Abstract
Microbial colonization of the human gastrointestinal tract plays an important role in establishing health and homeostasis. However, the time-dependent functional signatures of microbial and human proteins during early colonization of the gut have yet to be determined. To this end, we employed shotgun proteomics to simultaneously monitor microbial and human proteins in fecal samples from a preterm infant during the first month of life. Microbial community complexity increased over time, with compositional changes that were consistent with previous metagenomic and rRNA gene data. More specifically, the function of the microbial community initially involved biomass growth, protein production, and lipid metabolism, and then switched to more complex metabolic functions, such as carbohydrate metabolism, once the community stabilized and matured. Human proteins detected included those responsible for epithelial barrier function and antimicrobial activity. Some neutrophil-derived proteins increased in abundance early in the study period, suggesting activation of the innate immune system. Likewise, abundances of cytoskeletal and mucin proteins increased later in the time course, suggestive of subsequent adjustment to the increased microbial load. This study provides the first snapshot of coordinated human and microbial protein expression in a preterm infant's gut during early development.
Collapse
Affiliation(s)
- Jacque C Young
- Genome Sciences and Technology Graduate School, University of Tennessee, Knoxville, TN, USA.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Chongle Pan
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Rachel M Adams
- Genome Sciences and Technology Graduate School, University of Tennessee, Knoxville, TN, USA.,Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| | - Brandon Brooks
- Department of Earth and Planetary Sciences, University of California, Berkeley, CA, USA
| | - Jillian F Banfield
- Department of Earth and Planetary Sciences, University of California, Berkeley, CA, USA
| | - Michael J Morowitz
- Division of Pediatric General & Thoracic Surgery, University of Pittsburgh, Pittsburgh, PA, USA
| | - Robert L Hettich
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA
| |
Collapse
|
8
|
Dishaw LJ, Cannon JP, Litman GW, Parker W. Immune-directed support of rich microbial communities in the gut has ancient roots. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 47:36-51. [PMID: 24984114 PMCID: PMC4146740 DOI: 10.1016/j.dci.2014.06.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Revised: 05/30/2014] [Accepted: 06/21/2014] [Indexed: 05/12/2023]
Abstract
The animal gut serves as a primary location for the complex host-microbe interplay that is essential for homeostasis and may also reflect the types of ancient selective pressures that spawned the emergence of immunity in metazoans. In this review, we present a phylogenetic survey of gut host-microbe interactions and suggest that host defense systems arose not only to protect tissue directly from pathogenic attack but also to actively support growth of specific communities of mutualists. This functional dichotomy resulted in the evolution of immune systems much more tuned for harmonious existence with microbes than previously thought, existing as dynamic but primarily cooperative entities in the present day. We further present the protochordate Ciona intestinalis as a promising model for studying gut host-bacterial dialogue. The taxonomic position, gut physiology and experimental tractability of Ciona offer unique advantages in dissecting host-microbe interplay and can complement studies in other model systems.
Collapse
Affiliation(s)
- Larry J Dishaw
- Department of Pediatrics, University of South Florida Morsani College of Medicine, USF/ACH Children's Research Institute, 140 7th Avenue South, St. Petersburg, FL 33701, USA.
| | - John P Cannon
- Department of Pediatrics, University of South Florida Morsani College of Medicine, USF/ACH Children's Research Institute, 140 7th Avenue South, St. Petersburg, FL 33701, USA
| | - Gary W Litman
- Department of Pediatrics, University of South Florida Morsani College of Medicine, USF/ACH Children's Research Institute, 140 7th Avenue South, St. Petersburg, FL 33701, USA; Department of Molecular Genetics, All Children's Hospital-Johns Hopkins Medicine, 501 6th Avenue South, St. Petersburg, FL 33701, USA
| | - William Parker
- Department of Surgery, Duke University Medical Center, Box 2605, Durham, NC 27710, USA
| |
Collapse
|
9
|
Turco MM, Sousa MC. The structure and specificity of the type III secretion system effector NleC suggest a DNA mimicry mechanism of substrate recognition. Biochemistry 2014; 53:5131-9. [PMID: 25040221 PMCID: PMC4131895 DOI: 10.1021/bi500593e] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
![]()
Many pathogenic bacteria utilize
the type III secretion system
(T3SS) to translocate effector proteins directly into host cells,
facilitating colonization. In enterohemmorhagic Escherichia
coli (EHEC), a subset of T3SS effectors is essential for
suppression of the inflammatory response in hosts, including humans.
Identified as a zinc protease that cleaves NF-κB transcription
factors, NleC is one such effector. Here, we investigate NleC substrate
specificity, showing that four residues around the cleavage site in
the DNA-binding loop of the NF-κB subunit RelA strongly influence
the cleavage rate. Class I NF-κB subunit p50 is cleaved at a
reduced rate consistent with conservation of only three of these four
residues. However, peptides containing 10 residues on each side of
the scissile bond were not efficiently cleaved by NleC, indicating
that elements distal from the cleavage site are also important for
substrate recognition. We present the crystal structure of NleC and
show that it mimics DNA structurally and electrostatically. Consistent
with this model, mutation of phosphate-mimicking residues in NleC
reduces the level of RelA cleavage. We propose that global recognition
of NF-κB subunits by DNA mimicry combined with a high sequence
selectivity for the cleavage site results in exquisite NleC substrate
specificity. The structure also shows that despite undetectable similarity
of its sequence to those of other Zn2+ proteases beyond
its conserved HExxH Zn2+-binding motif, NleC is a member
of the Zincin protease superfamily, albeit divergent from its structural
homologues. In particular, NleC displays a modified Ψ-loop motif
that may be important for folding and refolding requirements implicit
in T3SS translocation.
Collapse
Affiliation(s)
- Michelle Marian Turco
- Department of Chemistry and Biochemistry, University of Colorado at Boulder , Boulder, Colorado 80309-0596, United States
| | | |
Collapse
|
10
|
Banerjee R, Balaji M, Sasikala M, Anuradha S, Rao GV, Nageshwar Reddy D. Granulomas of intestinal tuberculosis and Crohn's disease can be differentiated by CD73 cell surface marker expression: a pilot study. Dig Dis Sci 2013; 58:2301-7. [PMID: 23625284 DOI: 10.1007/s10620-013-2667-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Accepted: 03/27/2013] [Indexed: 12/13/2022]
Abstract
BACKGROUND Intestinal tuberculosis (ITB) and Crohn's disease are similar granulomatous disorders. Granulomas are present in both and difficult to differentiate on histopathology alone. A recent study demonstrated recruitment of mesenchymal cells (MSCs) at the periphery of granulomas in lymph node tuberculosis which suppressed T cell responses. We hypothesized that granulomas of ITB would also recruit MSCs to evade host immune response. AIM The purpose of this study was to demonstrate MSC markers in granulomas of ITB and evaluate whether distribution of MSC markers could differentiate between granulomas of Crohn's and ITB. METHODS We initially retrospectively enrolled 17 patients with confirmed ITB (8) or Crohn's (9) with granulomas on histopathology. Tissues were evaluated by immunofluorescence for MSC markers CD29, CD90, CD73 and absence of haematopoietic markers CD31, CD34, CD45 and CD14. Double-staining was done to confirm presence of MSCs. Subsequently, 23 postoperative specimens of Crohn's (18) and ITB (5) were analyzed for validation. RESULTS Overall, 27 Crohn's and 13 ITB cases were assessed. CD29 and CD90 positive cells were noted around both ITB and Crohn's granulomas. MSC marker CD73 was expressed around the granulomas of ITB alone and was completely absent in the Crohn's. The subsequent assessment of granulomas in postoperative specimens of Crohn's and ITB also showed similar results. CONCLUSION Granulomas of ITB and Crohn's disease can be differentiated by CD73 MSC surface marker expression. The differential CD73 expression around ITB granuloma indicates that Mycobacterium tuberculosis evades host immunity by recruiting MSCs with CD73 expression. MSCs with increased CD73 expression could be the future for therapeutic intervention in Crohn's.
Collapse
Affiliation(s)
- Rupa Banerjee
- Department of Medical Gastroenterology, Asian Institute of Gastroenterology, 6-3-661, Somajiguda, Hyderabad, India
| | | | | | | | | | | |
Collapse
|
11
|
Natividad JMM, Petit V, Huang X, de Palma G, Jury J, Sanz Y, Philpott D, Garcia Rodenas CL, McCoy KD, Verdu EF. Commensal and probiotic bacteria influence intestinal barrier function and susceptibility to colitis in Nod1-/-; Nod2-/- mice. Inflamm Bowel Dis 2012; 18:1434-46. [PMID: 22162005 DOI: 10.1002/ibd.22848] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 11/08/2011] [Indexed: 12/13/2022]
Abstract
BACKGROUND The intestinal microbiota regulates key host functions. It is unknown whether modulation of the microbiota can affect a genetically determined host phenotype. Polymorphisms in the Nucleotide oligomerization domain (Nod)-like receptor family confer genetic risk for inflammatory bowel disease (IBD). We investigated whether the intestinal microbiota and the probiotic strain Bifidobacterium breve NCC2950 affect intestinal barrier function and responses to intestinal injury in Nod1(-/-); Nod2(-/-) mice. METHODS Specific pathogen-free (SPF) Nod1(-/-); Nod2(-/-) mice and mice gnotobiotically derived with altered Schaedler flora (ASF) biota were used. SPF Nod1(+/-); Nod2(+/-) littermates (generated by crossing SPF Nod1(-/-); Nod2(-/-) and germ-free C57BL/6 mice) and ASF Nod1(+/-); Nod2(+/-) mice were used as controls. SPF mice were gavaged daily with 10(9) -CFU B. breve for 14 days before colitis induction. Denaturing gradient gel electrophoresis (DGGE) and real-time polymerase chain reaction (PCR) were used to assess microbiota composition. Intestinal permeability was assessed by in vitro and in vivo techniques. Expressions of epithelial apical junction proteins, mucin, and antimicrobial proteins were assessed by quantitative reverse-transcription PCR (qRT-PCR) and immunofluorescence. Responses to intestinal injury were investigated using an acute experimental model of colitis. RESULTS Under SPF conditions, Nod1(-/-); Nod2(-/-) mice had increased paracellular permeability, decreased E-cadherin, and lower colonic antimicrobial RegIII-γ expression compared to Nod1(+/-); Nod2(+/-) littermate controls. These changes were associated with increased susceptibility to colitis. ASF colonization or B. breve supplementation normalized RegIII-γ expression and decreased susceptibility to dextran sodium sulfate (DSS) colitis in Nod1(-/-); Nod2(-/-) mice. CONCLUSIONS The intestinal microbiota influences colitis severity in Nod1(-/-); Nod2(-/-) mice. The results suggest that colonization strategies with defined commensals or exogenous specific probiotic therapy may prevent intestinal inflammation in a genetically predisposed host.
Collapse
Affiliation(s)
- Jane M M Natividad
- Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Canada
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Singh UP, Singh NP, Singh B, Mishra MK, Nagarkatti M, Nagarkatti PS, Singh SR. Stem cells as potential therapeutic targets for inflammatory bowel disease. Front Biosci (Schol Ed) 2010; 2:993-1008. [PMID: 20515838 DOI: 10.2741/s115] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The incidence and prevalence of Crohn's disease and ulcerative colitis, the two major forms of inflammatory bowel disease (IBD), are rising. According to some estimates >1 million new cases of IBD arise in the United States annually. The conventional therapies available for IBD range from anti-inflammatory drugs to immunosuppressive agents, but these therapies generally fail to achieve satisfactory results due to their side effects. Interest in a new therapeutic option, that is, biological therapy, has gained much momentum recently due to its focus on different stages of the inflammatory process. Stem cell (SC) research has become a new direction for IBD therapy due to our recent understanding of cell populations involved in the pathogenic process. To this end, hematopoietic and mesenchymal stem cells are receiving more attention from IBD investigators. The intestinal environment, with its crypts and niches, supports incoming embryonic and hematopoietic stem cells and allows them to engraft and differentiate. The above findings suggest that, in the future, SC-based therapy will be a promising alternative to conventional therapy for IBD. In this review, we discuss SCs as potential therapeutic targets for future treatment of IBD.
Collapse
Affiliation(s)
- Udai P Singh
- Pathology and Microbiology and Immunology, School of Medicine, University of South Carolina, Columbia, SC 29208, USA
| | | | | | | | | | | | | |
Collapse
|
13
|
Vamadevan AS, Fukata M, Arnold ET, Thomas LS, Hsu D, Abreu MT. Regulation of Toll-like receptor 4-associated MD-2 in intestinal epithelial cells: a comprehensive analysis. Innate Immun 2009; 16:93-103. [PMID: 19710105 DOI: 10.1177/1753425909339231] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The intestinal epithelium maintains a state of controlled inflammation despite continuous contact with Gram-negative commensal bacteria and lipopolysaccharide (LPS) on its luminal surface. Recognition of LPS by the Toll-like receptor (TLR) 4/MD-2 complex results in pro-inflammatory gene expression and cytokine secretion in intestinal epithelial cells (IECs). We have shown that IECs express low levels of MD-2 and TLR4 and are poorly responsive to LPS. In this study, we did a comprehensive analysis to understand the immune-mediated and epigenetic mechanisms by which IECs down-regulate MD-2 expression. Expression of MD-2 and TLR4 mRNA was examined in human inflammatory bowel disease and intestinal epithelial cell lines (T84, HT-29, Caco-2). Nuclear factor-kappaB transcriptional activation was used as a measure of LPS responsiveness. Intestinal epithelial cells in patients with inflammatory bowel disease exhibited increased expression of MD-2 and TLR4 mRNA. Lipopolysaccharide responsiveness in IECs was polarized to the basolateral membrane. Bisulfite sequencing of the MD-2 promoter demonstrated methylation of CpG dinucleotides. Inhibition of methylation by 5-azacytidine and histone de-actylation by trichostatin A, two forms of epigenetic silencing, resulted in increased mRNA expression of MD-2 in IECs. These results demonstrate various molecular mechanisms by which IECs down-regulate MD-2 and, thereby, protect against dysregulated inflammation to commensal bacteria in the intestinal lumen.
Collapse
Affiliation(s)
- Arunan S Vamadevan
- Division of Gastroenterology, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida 33101, USA
| | | | | | | | | | | |
Collapse
|
14
|
Chaouche-Drider N, Kaparakis M, Karrar A, Fernandez MI, Carneiro LAM, Viala J, Boneca IG, Moran AP, Philpott DJ, Ferrero RL. A commensal Helicobacter sp. of the rodent intestinal flora activates TLR2 and NOD1 responses in epithelial cells. PLoS One 2009; 4:e5396. [PMID: 19401779 PMCID: PMC2671595 DOI: 10.1371/journal.pone.0005396] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Accepted: 04/02/2009] [Indexed: 12/30/2022] Open
Abstract
Helicobacter spp. represent a proportionately small but significant component of the normal intestinal microflora of animal hosts. Several of these intestinal Helicobacter spp. are known to induce colitis in mouse models, yet the mechanisms by which these bacteria induce intestinal inflammation are poorly understood. To address this question, we performed in vitro co-culture experiments with mouse and human epithelial cell lines stimulated with a selection of Helicobacter spp., including known pathogenic species as well as ones for which the pathogenic potential is less clear. Strikingly, a member of the normal microflora of rodents, Helicobacter muridarum, was found to be a particularly strong inducer of CXC chemokine (Cxcl1/KC, Cxcl2/MIP-2) responses in a murine intestinal epithelial cell line. Time-course studies revealed a biphasic pattern of chemokine responses in these cells, with H. muridarum lipopolysaccharide (LPS) mediating early (24–48 h) responses and live bacteria seeming to provoke later (48–72 h) responses. H. muridarum LPS per se was shown to induce CXC chemokine production in HEK293 cells stably expressing Toll-like receptor 2 (TLR2), but not in those expressing TLR4. In contrast, live H. muridarum bacteria were able to induce NF-κB reporter activity and CXC chemokine responses in TLR2–deficient HEK293 and in AGS epithelial cells. These responses were attenuated by transient transfection with a dominant negative construct to NOD1, and by stable expression of NOD1 siRNA, respectively. Thus, the data suggest that both TLR2 and NOD1 may be involved in innate immune sensing of H. muridarum by epithelial cells. This work identifies H. muridarum as a commensal bacterium with pathogenic potential and underscores the potential roles of ill-defined members of the normal flora in the initiation of inflammation in animal hosts. We suggest that H. muridarum may act as a confounding factor in colitis model studies in rodents.
Collapse
Affiliation(s)
| | - Maria Kaparakis
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Abdulgader Karrar
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Maria-Isabel Fernandez
- Institut Pasteur, Unité de Pathogénie Microbienne Moléculaire, Paris, France
- INSERM U389, Paris, France
| | - Letitia A. M. Carneiro
- Institut Pasteur, Groupe d'Immunité Innée et Signalisation, Paris, France
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Jérôme Viala
- Institut Pasteur, Groupe d'Immunité Innée et Signalisation, Paris, France
| | - Ivo Gomperts Boneca
- Institut Pasteur, Unité de Pathogénie Bactérienne des Muqueuses, Paris, France
- Institut Pasteur, Groupe de Biologie et Génétique de la Paroi Bactérienne, Paris, France
- INSERM, Groupe Avenir, Paris, France
| | - Anthony P. Moran
- Department of Microbiology, National University of Ireland, Galway, Ireland
| | - Dana J. Philpott
- Institut Pasteur, Groupe d'Immunité Innée et Signalisation, Paris, France
- Department of Immunology, University of Toronto, Toronto, Ontario, Canada
| | - Richard L. Ferrero
- Institut Pasteur, Unité de Pathogénie Bactérienne des Muqueuses, Paris, France
- Department of Microbiology, Monash University, Clayton, Victoria, Australia
- * E-mail:
| |
Collapse
|
15
|
Singh UP, Singh S, Singh R, Cong Y, Taub DD, Lillard JW. CXCL10-producing mucosal CD4+ T cells, NK cells, and NKT cells are associated with chronic colitis in IL-10(-/-) mice, which can be abrogated by anti-CXCL10 antibody inhibition. J Interferon Cytokine Res 2008; 28:31-43. [PMID: 18370870 DOI: 10.1089/jir.2007.0059] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We have shown previously that there is a temporal increase in the levels of CXCL10 and CXCR3 mRNA during spontaneous murine colitis. We now show that CXCL10 is significantly expressed by mucosal CD4+ T cells, natural killer (NK) cells, and NKT cells, but not by dendritic cells (DCs), during chronic murine colitis. CXCL10 blockade alleviated chronic colitis and attenuated the associated increase in serum amyloid A (SAA), interleukin-12 (IL-12)p40, tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), IL-1 alpha, and IL-1 beta levels as well as in the number of CD4+ T, NKT, and NK cells that express CXCL10 and CXCR3, compared with groups treated with control antibody (Ab). After CXCL10 blockade, the number of CXCR3+ DCs in the mesenteric lymph nodes (MLNs) and Peyer's patches (PPs) were increased to levels found before the onset of colitis. In contrast, the numbers of splenic and intestinal lamina propria (LP) CXCR3+ DCs were reduced after anti-CXCL10 Ab treatment, compared with controls. Ex vivo antigen and CXCL10 stimulation of mucosal cells caused an increase in MHC class II, CD40, and CD86 as well as a decrease in CD30 ligand (CD30L) expression by DCs. This study provides insights into CXCL10 expression during inflammatory bowel disease (IBD) and the cellular and molecular mechanisms of CXCL10-mediated colitis. Our data also support the premise that CXCL10 blockade can attenuate chronic colitis by preventing the activation and recruitment of CXCR3+ leukocytes during IBD.
Collapse
Affiliation(s)
- Udai P Singh
- Department of Microbiology and Immunology, Morehouse School of Medicine, Atlanta, GA 30310, USA
| | | | | | | | | | | |
Collapse
|
16
|
Singh UP, Singh S, Singh R, Karls RK, Quinn FD, Potter ME, Lillard JW. Influence of Mycobacterium avium subsp. paratuberculosis on colitis development and specific immune responses during disease. Infect Immun 2007; 75:3722-8. [PMID: 17502388 PMCID: PMC1952017 DOI: 10.1128/iai.01770-06] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The granulomatous and intramural inflammation observed in cases of inflammatory bowel diseases (IBD) and veterinary Johne's disease suggests that Mycobacterium avium subsp. paratuberculosis is a causative agent. However, an incomplete understanding of the immunological steps responsible for the pathologies of IBD makes this conclusion uncertain. Sera from interleukin-10-deficient (IL-10(-/-)) mice with spontaneous colitis displayed significantly higher M. avium subsp. paratuberculosis-specific immunoglobulin G2a antibody responses than did sera from similar mice without disease. Pathogen-free IL-10(-/-) mice received control vehicle or the vehicle containing heat-killed or live M. avium subsp. paratuberculosis. Mucosal CD4(+) T cells from the mice that developed colitis proliferated and secreted higher levels of gamma interferon and tumor necrosis factor alpha after ex vivo stimulation with a Vbeta11(+) T-cell receptor-restricted peptide from the MPT59 antigen (Ag85B) than those secreted from cells from mice before the onset of colitis. The data from this study provide important information regarding the mechanisms of colitis in IL-10(-/-) mice, which are driven in part by Ag85B-specific T cells. The data suggest a plausible mechanism of Ag-specific T-cell responses in colitis driven by potent Ags conserved in Mycobacterium species.
Collapse
MESH Headings
- Animals
- Antibodies, Bacterial/blood
- Antigens, Bacterial/immunology
- CD4-Positive T-Lymphocytes/immunology
- Colitis/immunology
- Colitis/microbiology
- Colitis/pathology
- Disease Models, Animal
- Enzyme-Linked Immunosorbent Assay
- Female
- Humans
- Immunoglobulin G/blood
- Interferon-gamma/biosynthesis
- Interleukin-10/deficiency
- Intestinal Mucosa/immunology
- Ligands
- Mice
- Mice, Knockout
- Mycobacterium avium subsp. paratuberculosis/immunology
- Paratuberculosis/immunology
- Paratuberculosis/pathology
- Peptides/immunology
- Receptors, Antigen, T-Cell/immunology
- Receptors, CXCR3
- Receptors, Chemokine/agonists
- Receptors, Chemokine/immunology
- Specific Pathogen-Free Organisms
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocytes, Helper-Inducer/cytology
- T-Lymphocytes, Helper-Inducer/immunology
- Th1 Cells/immunology
- Tumor Necrosis Factor-alpha/biosynthesis
Collapse
Affiliation(s)
- Udai P Singh
- Brown Cancer Center, Department of Microbiology and Immunology, University of Louisville, 580 S. Preston Street, Baxter II/Room 304C, Louisville, KY 40202, USA
| | | | | | | | | | | | | |
Collapse
|
17
|
Buddington RK, Kelly-Quagliana K, Buddington KK, Kimura Y. Non–digestible oligosaccharides and defense functions: lessons learned from animal models. Br J Nutr 2007. [DOI: 10.1079/bjn/2002542] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Animals are constantly exposed to a diversity of health challenges and the gastrointestinal tract (GIT) is a major, if not the principal, site of exposure. Animal models and a limited number of human clinical studies have shown that the assemblages and metabolic activities of the resident bacteria are important determinants of the effectiveness of the various host defense mechanisms and thereby influence the ability of animals to respond to health challenges. The assemblages of bacteria resident in the GIT provide a first line of defense that can exclude invading pathogens, reduce the proliferation of opportunistic pathogens already resident in the GIT, and reduce the availability, carcinogenicity, or toxicity of noxious chemicals. The mucosa of the GIT is a second, multilayered line of defense that includes the mucous and other secretions, the epithelial cells, and immune-associated cells scattered within and under the epithelium. The final line of defense contends with pathogens or noxious chemicals that transcend the mucosal barrier and enter the host and consists of the innate and acquired components of the systemic immune system and the xenobiotic metabolizing enzymes. The lactic acid producing bacteria (LAB) are considered to be immunomodulatory and directly or indirectly influence the GIT and systemic defense functions. Corresponding with this, supplementing the diet with inulin, oligofructose, or other nondigestible oligosaccharides that increase the densities and metabolic capacities of the LAB enhances defense mechanisms of the host, increases resistance to various health challenges, and accelerates recovery of the GIT after disturbances.
Collapse
|
18
|
Helwig U, Lammers KM, Rizzello F, Brigidi P, Rohleder V, Caramelli E, Gionchetti P, Schrezenmeir J, Foelsch UR, Schreiber S, Campieri M. Lactobacilli, bifidobacteria and E. coli nissle induce pro- and anti-inflammatory cytokines in peripheral blood mononuclear cells. World J Gastroenterol 2006; 12:5978-86. [PMID: 17009396 PMCID: PMC4124405 DOI: 10.3748/wjg.v12.i37.5978] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate whether the stimulation of peripheral blood mononuclear cells (PBMNC) with the cell debris and cell extraction of different probiotic strains is similar or species specific.
METHODS: Three strains of bifidobacteria, 4 strains of lactobacilli, and E. coli nissle were sonicated and centrifuged in order to divide them into cell extract and cell debris. PBMNC were separated by density gradient and incubated for 36 h with either the cell debris or the cell extract of single strains of probiotic bacteria in doses from 102 to 108 CFU/mL. Cell supernatants were taken and interleukin (IL)-10, IL-1β, and tumor necosis factor (TNF)-α were determined by ELISA.
RESULTS: Depending on the species super-family, the strains had different stimulation patterns. Except for both L. casei strains, the cell extract of bifidobacteria and lactobacilli had less stimulating capacity than cell debris, whereas the cell extract of E. coli nissle had similar stimulating properties to that of the cell debris of the strain and significantly more stimulating capacity than that of bifidobacteria and lactobacilli. The cell debris of bifidobacteria stimulated more cytokine release than the cell debris of lactobacilli. The cell debris of lactobacilli did not have a stimulating capacity when lower concentrations were used. Neither cell extraction nor cell debris had an inhibitory effect on the production of the tested cytokines by stimulated PBMNC.
CONCLUSION: The incubation of probiotic strains, which have been used in clinical trials for inflammatory diseases, with immunocompetent cells leads to different species specific reactions. High IL-10 response to cell debris of bifidobacteria and E. coli nissle can be found. This corresponds to positive effects of bifidobacteria and E. coli nissle in clinical trials for inflammatory bowel disease compared to negative outcomes obtained with lactobacilli.
Collapse
Affiliation(s)
- Ulf Helwig
- University Hospital Schleswig-Holstein, Campus Kiel, 1st Medical Department, 24105 Kiel, Germany.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Liévin-Le Moal V, Servin AL. The front line of enteric host defense against unwelcome intrusion of harmful microorganisms: mucins, antimicrobial peptides, and microbiota. Clin Microbiol Rev 2006; 19:315-37. [PMID: 16614252 PMCID: PMC1471992 DOI: 10.1128/cmr.19.2.315-337.2006] [Citation(s) in RCA: 353] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The intestinal tract is a complex ecosystem that combines resident microbiota and the cells of various phenotypes with complex metabolic activities that line the epithelial wall. The intestinal cells that make up the epithelium provide physical and chemical barriers that protect the host against the unwanted intrusion of microorganisms that hijack the cellular molecules and signaling pathways of the host and become pathogenic. Some of the organisms making up the intestinal microbiota also have microbicidal effects that contribute to the barrier against enteric pathogens. This review describes the two cell lineages present in the intestinal epithelium: the goblet cells and the Paneth cells, both of which play a pivotal role in the first line of enteric defense by producing mucus and antimicrobial peptides, respectively. We also analyze recent insights into the intestinal microbiota and the mechanisms by which some resident species act as a barrier to enteric pathogens. Moreover, this review examines whether the cells producing mucins or antimicrobial peptides and the resident microbiota act in partnership and whether they function individually and/or synergistically to provide the host with an effective front line of defense against harmful enteric pathogens.
Collapse
Affiliation(s)
- Vanessa Liévin-Le Moal
- Unité 756 INSERM, Faculté de Pharmacie Paris XI, Signalisation et Physiopathologie des Cellules Epithéliales, Institut National de la Santé et de la Recherche Médicale, F-92296 Chātenay-Malabry, France
| | | |
Collapse
|
20
|
O'Mahony L, O'Callaghan L, McCarthy J, Shilling D, Scully P, Sibartie S, Kavanagh E, Kirwan WO, Redmond HP, Collins JK, Shanahan F. Differential cytokine response from dendritic cells to commensal and pathogenic bacteria in different lymphoid compartments in humans. Am J Physiol Gastrointest Liver Physiol 2006; 290:G839-45. [PMID: 16293657 DOI: 10.1152/ajpgi.00112.2005] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Resident host microflora condition and prime the immune system. However, systemic and mucosal immune responses to bacteria may be divergent. Our aim was to compare, in vitro, cytokine production by human mononuclear and dendritic cells (DCs) from mesenteric lymph nodes (MLNs) and peripheral blood mononuclear cells (PBMCs) to defined microbial stimuli. Mononuclear cells and DCs isolated from the MLN (n = 10) and peripheral blood (n = 12) of patients with active colitis were incubated in vitro with the probiotic bacteria Lactobacillus salivarius UCC118 or Bifidobacterium infantis 35624 or the pathogenic organism Salmonella typhimurium UK1. Interleukin (IL)-12, tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, and IL-10 cytokine levels were quantified by ELISA. PBMCs and PBMC-derived DCs secreted TNF-alpha in response to the Lactobacillus, Bifidobacteria, and Salmonella strains, whereas MLN cells and MLN-derived DCs secreted TNF-alpha only in response to Salmonella challenge. Cells from the systemic compartment secreted IL-12 after coincubation with Salmonella or Lactobacilli, whereas MLN-derived cells produced IL-12 only in response to Salmonella. PBMCs secreted IL-10 in response to the Bifidobacterium strain but not in response to the Lactobacillus or Salmonella strain. However, MLN cells secreted IL-10 in response to Bifidobacteria and Lactobacilli but not in response to Salmonella. In conclusion, commensal bacteria induced regulatory cytokine production by MLN cells, whereas pathogenic bacteria induce T cell helper 1-polarizing cytokines. Commensal-pathogen divergence in cytokine responses is more marked in cells isolated from the mucosal immune system compared with PBMCs.
Collapse
Affiliation(s)
- Liam O'Mahony
- Alimentary Pharmabiotic Centre, University College Cork, National University of Ireland
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Mitsuyama K, Suzuki A, Matsumoto S, Tomiyasu N, Takaki K, Takedatsu H, Masuda J, Handa K, Harada K, Nishida H, Toyonaga A, Sata M. Diminished cytokine signalling against bacterial components in mononuclear leucocytes from ulcerative colitis patients after leukocytapheresis. Clin Exp Immunol 2005; 141:130-40. [PMID: 15958079 PMCID: PMC1809412 DOI: 10.1111/j.1365-2249.2005.02825.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Infiltration by circulating inflammatory cells is a prominent local inflammatory feature of ulcerative colitis (UC). Several trials have suggested that leukocytapheresis by filtration can benefit patients with active UC. We investigated how this therapy might modulate the inflammatory response. Patients with active UC who were beginning repeated filtration leukocytapheresis were studied. Mononuclear cell preparations were obtained from blood before and after the first treatment, and expression of cytokine signalling components and the cell-proliferative response were analysed in vitro. Leukocytapheresis reduced lipopolysaccharide-induced production of proinflammatory cytokines (interleukin-1, -6, -8 and tumour necrosis factor-alpha, P < 0.05 for all) and activation of intracellular signalling components (nuclear factor-kappaB, mitogen-activated protein kinases, and signal transducer and activator of transcription-3), as well as surface expression of toll-like receptor-4 (P < 0.05) in mononuclear cells. The therapy also reduced the cell-proliferative response by mononuclear cells stimulated with sonicated bacterial preparations from autologous intestine (P < 0.05). These results indicate that activated mononuclear cells in the peripheral blood of patients with active UC are removed by leukocytapheresis and replaced by cells with a lower activation status. This replacement may partly explain the therapeutic benefit.
Collapse
Affiliation(s)
- K Mitsuyama
- Second Department of Medicine, Kurume University School of Medicine, Kurume, Japan
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Mylonaki M, Rayment NB, Rampton DS, Hudspith BN, Brostoff J. Molecular characterization of rectal mucosa-associated bacterial flora in inflammatory bowel disease. Inflamm Bowel Dis 2005; 11:481-7. [PMID: 15867588 DOI: 10.1097/01.mib.0000159663.62651.4f] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Colorectal bacteria may play a role in the pathogenesis of inflammatory bowel disease (IBD). To test the hypothesis that, in affected patients, the numbers of potentially protective mucosal bacteria might be reduced and pathogenic species increased, we compared rectal mucosa-associated flora in patients with IBD and normal controls. METHODS Snap-frozen rectal biopsies taken at routine diagnostic colonoscopy from 33 patients with ulcerative colitis, 6 patients with Crohn's disease, and 14 controls with normal colonoscopy were processed, and individual bacterial groups were counted using fluorescent in situ hybridization. RESULTS Bacteria were mostly found apposed to the epithelial surface and within crypts. Epithelium-associated counts of bifidobacteria in active [median 15/mm of epithelial surface (range, 4-56), n = 14] and quiescent ulcerative colitis [26/mm (range, 11-140), n = 19] were lower than in controls [56/mm (range, 0-144), n = 14; P = 0.006 and P = 0.03, respectively]. Conversely, epithelium-associated Escherichia coli counts were higher in active [82/mm (range, 56-136)] than inactive ulcerative colitis [6/mm (range, 0-136), P = 0.0001] or controls [0/mm (range, 0-16), P < 0.0001]. Epithelium-associated clostridia counts were also higher in active [3/mm (range, 0-9)] than inactive colitis [0/mm (range, 0-9), P = 0.03] or controls [0/mm (range, 0-1); P = 0.0007]. Epithelium-associated E. coli counts were higher in Crohn's disease [42/mm (range, 3-90), n = 6] than controls (P = 0.0006). E. coli were also found as individual bacteria and in clusters in the lamina propria in ulcerative colitis and Crohn's disease but in none of the controls (P < 0.01). Numbers of Lactobacillus and Bacteroides showed no differences between patient groups. CONCLUSIONS The reduction in mucosa-associated bifidobacteria and increase in E. coli and clostridia in patients with IBD supports the hypothesis that an imbalance between potentially beneficial and pathogenic bacteria may contribute to its pathogenesis.
Collapse
Affiliation(s)
- Maria Mylonaki
- Academic Department of Adult and Paediatric Gastroenterology, Barts and the London School of Medicine and Dentistry, UK
| | | | | | | | | |
Collapse
|
23
|
Affiliation(s)
- Fergus Shanahan
- Alimentary Pharmabiotic Centre and Department of Medicine, University College Cork, National University of Ireland.
| |
Collapse
|
24
|
Kim JM, Kim JS, Jung HC, Oh YK, Chung HY, Lee CH, Song IS. Helicobacter pylori infection activates NF-kappaB signaling pathway to induce iNOS and protect human gastric epithelial cells from apoptosis. Am J Physiol Gastrointest Liver Physiol 2003; 285:G1171-80. [PMID: 12919943 DOI: 10.1152/ajpgi.00502.2002] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Helicobacter pylori infection induces apoptosis and inducible nitric oxide synthase (iNOS) expression in gastric epithelial cells. In this study, we investigated the effects of NF-kappaB activation and iNOS expression on apoptosis in H. pylori-infected gastric epithelial cells. The suppression of NF-kappaB significantly increased caspase-3 activity and apoptosis in H. pylori-infected MKN-45 and Hs746T gastric epithelial cell lines as well as primary gastric epithelial cells. An NF-kappaB signaling pathway via NF-kappaB-inducing kinase and IkappaB kinase-beta activation was found to be involved in the inhibition of apoptosis in H. pylori-infected gastric epithelial cells. In gastric epithelial cells transfected with retrovirus containing IkappaBalpha superrepressor, iNOS mRNA and protein levels were reduced, indicating that H. pylori infection induced the expression of iNOS by activating NF-kappaB. Moreover, a NO donor, S-nitroso-N-acetylpenicillamine (100 microM), decreased caspase-3 activity and apoptosis in NF-kappaB-suppressed cells infected with H. pylori. These results suggest that NF-kappaB activation may play a role in protecting gastric epithelial cells from H. pylori-induced apoptosis by upregulating endogenous iNOS.
Collapse
Affiliation(s)
- Jung Mogg Kim
- Department of Microbiology and Institute of Biomedical Science, Hanyang University College of Medicine, Seoul, Korea
| | | | | | | | | | | | | |
Collapse
|
25
|
Cui HH, Chen CL, Yang YJ, Zhang ZJ, Zhang YD, Cui YS. Expression of Th1/Th2 cytokines in intestinal mucosa of ulcerative colitis. Shijie Huaren Xiaohua Zazhi 2003; 11:1524-1527. [DOI: 10.11569/wcjd.v11.i10.1524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM To investigate the effects of the expression of Th1/Th2 cytokines in intestinal mucosa with ulcerative colitis.
METHODS Thirty patients (24 males, 6 females, age 18-79 years) with severe ulcerative colitis (UC) were examined by colonoscope, the diagnosis was confirmed by histological method. Bacterial infection was excluded through consecutive stool cultures twice. And ameba, schistosomiasis, gastroen-terological cancer and endocrine diseases were also excluded. Ulcerative colitis was found in omni-colon (n = 15) , sigmoid (n = 9), rectum (n = 6), respectively. Its clinical categories included relapse (n = 20), persistent (n = 7) and initial (n = 3).They were treated by Sulphasalazine (SASP) and glucocorticoid after histological diagnosis. Eight weeks later, they were re-examined by colonoscope. The expression of cytokines in the intestinal mucosa of UC patients were detected by a semi-quantitative assay, reverse transcription-polymerase chain reaction(RT-PCR) before and after treatment respectively.
RESULTS Comparison with control groups, the expression of TNF-α, IL-2 was increased but IL-4 was decreased in the intestinal mucosa in acute stage. Sulphasalazine (SASP) and glucocorticoid inhibited inflammation by reducing the expression of TNF-α from 1.22±0.02 to 0.78±0.08 (P<0.01) and of IL-2 from 0.82±0.06 to 0.47±0.04 (P<0.01), and elevate the expression of IL-10 from 0.68±0.03 to 0.91±0.02(P<0.01).
CONCLUSION There is an imbalance of Th1 and Th2 phenotype cytokine in patients with ulcerative colitis.
Collapse
Affiliation(s)
- Hai-Hong Cui
- Chinese PLA Institute for Digestive Diseases, Nanfang Hospital, First Military Medical University, Guangzhou 50515, Guangdong Province, China
| | - Cun-Long Chen
- Chinese PLA Institute for Digestive Diseases, Nanfang Hospital, First Military Medical University, Guangzhou 50515, Guangdong Province, China
| | - Yu-Jie Yang
- Chinese PLA Institute for Digestive Diseases, Nanfang Hospital, First Military Medical University, Guangzhou 50515, Guangdong Province, China
| | - Zuo-Jian Zhang
- Institute For Digestive Disease, Jinan Air Force Hospital, Jinan 250031, Shandong Province, China
| | - Yao-Dong Zhang
- Institute For Digestive Disease, Jinan Air Force Hospital, Jinan 250031, Shandong Province, China
| | - Yao-Sheng Cui
- Institute For Digestive Disease, Jinan Air Force Hospital, Jinan 250031, Shandong Province, China
| |
Collapse
|
26
|
Bollinger RR, Everett ML, Palestrant D, Love SD, Lin SS, Parker W. Human secretory immunoglobulin A may contribute to biofilm formation in the gut. Immunology 2003; 109:580-7. [PMID: 12871226 PMCID: PMC1782994 DOI: 10.1046/j.1365-2567.2003.01700.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
It is critical, both for the host and for the long-term benefit of the bacteria that colonize the gut, that bacterial overgrowth with subsequent bacterial translocation, which may lead to sepsis and death of the host, be avoided. Secretory IgA (sIgA) is known to be a key factor in this process, agglutinating bacteria and preventing their translocation in a process termed 'immune exclusion'. To determine whether human sIgA might facilitate the growth of normal enteric bacteria under some conditions, the growth of human enteric bacteria on cultured, fixed human epithelial cells was evaluated in the presence of sIgA or various other proteins. Human sIgA was found to facilitate biofilm formation by normal human gut flora and by Escherichia coli on cultured human epithelial cell surfaces under conditions in which non-adherent bacteria were repeatedly washed away. In addition, the presence of sIgA resulted in a 64% increase in adherence of E. coli to live cultured epithelial cells over a 45-min period. Mucin, another defence factor thought to play a key role in immune exclusion, was found to facilitate biofilm formation by E. coli. Our findings suggest that sIgA may contribute to biofilm formation in the gut.
Collapse
Affiliation(s)
- R Randal Bollinger
- Department of Surgery, Duke University Medical CenterDurham, NC, USA
- Department of Immunology, Duke University Medical CenterDurham, NC, USA
| | - Mary Lou Everett
- Department of Surgery, Duke University Medical CenterDurham, NC, USA
| | - Daniel Palestrant
- Department of Surgery, Duke University Medical CenterDurham, NC, USA
| | - Stephanie D Love
- Department of Surgery, Duke University Medical CenterDurham, NC, USA
| | - Shu S Lin
- Department of Surgery, Duke University Medical CenterDurham, NC, USA
| | - William Parker
- Department of Surgery, Duke University Medical CenterDurham, NC, USA
| |
Collapse
|
27
|
Allaker RP, Kapas S. Adrenomedullin expression by gastric epithelial cells in response to infection. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2003; 10:546-51. [PMID: 12853384 PMCID: PMC164278 DOI: 10.1128/cdli.10.4.546-551.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Many surface epithelial cells express adrenomedullin, a multifunctional peptide found in a wide number of body and cell systems. Recently, we and others have proposed that adrenomedullin has an important novel role in host defense. This peptide has many properties in common with other cationic antimicrobial peptides, including the human beta-defensins. Upon exposure of human gastric epithelial cells to viable cells of invasive or noninvasive strains of Helicobacter pylori, Escherichia coli, Salmonella enterica, or Streptococcus bovis, a significant increase in adrenomedullin secretion from these cells was demonstrated. Adrenomedullin gene expression was also increased in response to these microorganisms. Similar observations were noted when these cells were incubated with proinflammatory cytokines such as interleukin 1 alpha (IL-1 alpha), IL-6, tumor necrosis factor alpha and lipopolysaccharide. In cultured cells and an animal infection model, increased adrenomedullin peptide and gene expression was demonstrated when exposed to E. coli or Mycobacterium paratuberculosis, respectively. The data suggest there is a strong association between epithelial infection, inflammation, and adrenomedullin expression, which may have clinical relevance. The regulation of adrenomedullin expression may have therapeutic applications, such as improving or enhancing mucosal immunity.
Collapse
Affiliation(s)
- Robert P Allaker
- Oral Microbiology Unit, Barts and the London, Queen Mary's School of Medicine and Dentistry, University of London, London E1 2AD, United Kingdom.
| | | |
Collapse
|
28
|
Morafo V, Srivastava K, Huang CK, Kleiner G, Lee SY, Sampson HA, Li AM. Genetic susceptibility to food allergy is linked to differential TH2-TH1 responses in C3H/HeJ and BALB/c mice. J Allergy Clin Immunol 2003; 111:1122-8. [PMID: 12743580 DOI: 10.1067/mai.2003.1463] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND Although food allergy is a serious health problem in westernized countries, factors influencing the development of food allergy are largely unknown. Appropriate murine models of food allergy would be useful in understanding the mechanisms underlying food allergy in human subjects. OBJECTIVE We sought to determine the susceptibility of different strains of mice to food hypersensitivity. METHODS C3H/HeJ and BALB/c mice were sensitized to cow's milk (CM) or peanut by means of intragastric administration, with cholera toxin as a mucosal adjuvant. Mice were then challenged with CM or peanut. Antigen-specific IgE levels, anaphylactic symptoms, plasma histamine levels, and splenocyte cytokine profiles of these 2 strains were compared. RESULTS CM-specific IgE levels were significantly increased only in the C3H/HeJ strain, 87% of which exhibited systemic anaphylactic reactions accompanied by significantly increased plasma histamine levels in response to challenge. BALB/c mice exhibited no significant CM-specific IgE response, increased plasma histamine levels, or anaphylactic symptoms. After peanut challenge, 100% of peanut-sensitized C3H/HeJ mice exhibited high levels of peanut-specific IgE and anaphylactic symptoms. In contrast, no hypersensitivity reactions were detected in BALB/c mice, despite the presence of significant serum peanut-specific IgE levels. Splenocytes from CM- and peanut-sensitized C3H/HeJ mice exhibited significantly increased IL-4 and IL-10 secretion, whereas splenocytes from BALB/c mice exhibited significantly increased IFN-gamma secretion. CONCLUSION Induction of food-induced hypersensitivity reactions in mice is strain dependent, with C3H/HeJ mice being susceptible and BALB/c mice being resistant. This strain-dependent susceptibility to food allergy is associated with differential T(H)2-T(H)1 responses after intragastric food allergen sensitization.
Collapse
Affiliation(s)
- Vivian Morafo
- Department of Pediatrics, Mount Sinai School of Medicine, New York 10029-6574, USA
| | | | | | | | | | | | | |
Collapse
|
29
|
Li XM, Srivastava K, Huleatt JW, Bottomly K, Burks AW, Sampson HA. Engineered recombinant peanut protein and heat-killed Listeria monocytogenes coadministration protects against peanut-induced anaphylaxis in a murine model. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:3289-95. [PMID: 12626588 DOI: 10.4049/jimmunol.170.6.3289] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Peanut allergy (PNA) is the major cause of fatal and near-fatal anaphylactic reactions to foods. Traditional immunotherapy using peanut (PN) protein is not an option for PNA therapy because of the high incidence of adverse reactions. We investigated the effects of s.c. injections of engineered (modified) recombinant PN proteins and heat-killed Listeria monocytogenes (HKLM) as an adjuvant on anaphylactic reactions in a mouse model of PN allergy. PN-allergic C3H/HeJ mice were treated s.c. with a mixture of the three major PN allergens and HKLM (modified (m)Ara h 1-3 plus HKLM). The effects on anaphylactic reactions following PN challenge and the association with Ab levels and cytokine profiles were determined. Although all mice in the sham-treated groups exhibited anaphylactic symptoms with a median symptom score of 3, only 31% of mice in the mAra h 1-3 plus HKLM group developed mild anaphylaxis, with a low median symptom score of 0.5. Alterations in core body temperature, bronchial constriction, plasma histamine, and PN-specific IgE levels were all significantly reduced. This protective effect was markedly more potent than in the mAra h 1-3 protein alone-treated group. HKLM alone did not have any protective effect. Reduced IL-5 and IL-13, and increased IFN-gamma levels were observed only in splenocytes cultures from mAra h 1-3 plus HKLM-treated mice. These results show that immunotherapy with modified PN proteins and HKLM is effective for treating PN allergy in this model, and may be a potential approach for treating PNA.
Collapse
MESH Headings
- 2S Albumins, Plant
- Adjuvants, Immunologic/administration & dosage
- Adjuvants, Immunologic/therapeutic use
- Allergens/administration & dosage
- Allergens/therapeutic use
- Anaphylaxis/blood
- Anaphylaxis/immunology
- Anaphylaxis/prevention & control
- Animals
- Antigens, Plant
- Arachis/adverse effects
- Arachis/immunology
- Bacterial Vaccines/administration & dosage
- Bacterial Vaccines/therapeutic use
- Cytokines/antagonists & inhibitors
- Cytokines/biosynthesis
- Disease Models, Animal
- Down-Regulation/immunology
- Drug Therapy, Combination
- Female
- Food Hypersensitivity/blood
- Food Hypersensitivity/immunology
- Food Hypersensitivity/prevention & control
- Glycoproteins/administration & dosage
- Glycoproteins/therapeutic use
- Histamine/blood
- Histamine Antagonists/administration & dosage
- Histamine Antagonists/therapeutic use
- Immunoglobulin E/biosynthesis
- Immunoglobulin G/biosynthesis
- Intubation, Gastrointestinal
- Listeria monocytogenes/immunology
- Membrane Proteins
- Mice
- Mice, Inbred C3H
- Plant Proteins/administration & dosage
- Plant Proteins/therapeutic use
- Protein Engineering
- Recombinant Proteins/administration & dosage
- Recombinant Proteins/therapeutic use
- Seed Storage Proteins
- Th1 Cells/immunology
- Th1 Cells/metabolism
- Th2 Cells/immunology
- Th2 Cells/metabolism
- Up-Regulation/immunology
- Vaccines, Attenuated/administration & dosage
- Vaccines, Attenuated/therapeutic use
Collapse
Affiliation(s)
- Xiu-Min Li
- Department of Pediatrics, Mount Sinai School of Medicine, New York, NY 10029, USA.
| | | | | | | | | | | |
Collapse
|
30
|
Abstract
Several biological therapies (monoclonal antibodies, designer molecules, recombinant cytokines) have been tested for clinical efficacy in inflammatory bowel disease, and some have been found to be effective. Anti-TNF-alpha (anti-tumour necrosis factor-alpha) antibody therapy is an important treatment modality in the treatment of active and fistulating Crohn's disease and should be considered in patients who fail standard medical therapies. Treatment with TNF-alpha-neutralizing antibodies is associated with immunosuppression that may lead to opportunistic infections and reactivation of tuberculosis, and patients should undergo Mantoux testing prior to treatment. Several other monoclonal antibodies, including anti-IL12 and anti-IFN-gamma, are currently in development for Crohn's disease. Other new approaches include ex vivo generation of regulatory T lymphocytes and antibodies that target and kill (subpopulations of) memory T lymphocytes.
Collapse
Affiliation(s)
- S J H van Deventer
- Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands
| |
Collapse
|
31
|
Abstract
Feline inflammatory bowel disease (FIBD) is characterized by persistent gastrointestinal signs, histologic evidence of mucosal inflammation, and responsiveness to immunotherapeutic intervention. Since a concise and comprehensive review of IBD has been recently presented (Jergens 1999 ), the purpose of this overview is to provide current perspectives on FIBD, and strategies for dealing with patients that fail to respond to routine medical management.
Collapse
Affiliation(s)
- A E Jergens
- Department of Clinical Veterinary Sciences College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA
| |
Collapse
|
32
|
Melmed G, Thomas LS, Lee N, Tesfay SY, Lukasek K, Michelsen KS, Zhou Y, Hu B, Arditi M, Abreu MT. Human intestinal epithelial cells are broadly unresponsive to Toll-like receptor 2-dependent bacterial ligands: implications for host-microbial interactions in the gut. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:1406-15. [PMID: 12538701 DOI: 10.4049/jimmunol.170.3.1406] [Citation(s) in RCA: 326] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Intestinal epithelial cells (IEC) interact with a high density of Gram-positive bacteria and are active participants in mucosal immune responses. Recognition of Gram-positive organisms by Toll-like receptor (TLR)2 induces proinflammatory gene expression by diverse cells. We hypothesized that IEC are unresponsive to Gram-positive pathogen-associated molecular patterns and sought to characterize the functional responses of IEC to TLR2-specific ligands. Human colonic epithelial cells isolated by laser capture microscopy and IEC lines (Caco-2, T84, HT-29) were analyzed for expression of TLR2, TLR6, TLR1, and Toll inhibitory protein (Tollip) mRNA by RT-PCR and quantitative real-time PCR. Response to Gram-positive bacterial ligands was measured by NF-kappa B reporter gene activation and IL-8 secretion. TLR2 protein expression was analyzed by immunofluorescence and flow cytometry. Colonic epithelial cells and lamina propria cells from both uninflamed and inflamed tissue demonstrate low expression of TLR2 mRNA compared with THP-1 monocytes. IECs were unresponsive to TLR2 ligands including the staphylococcal-derived Ags phenol soluble modulin, peptidoglycan, and lipotechoic acid and the mycobacterial-derived Ag soluble tuberculosis factor. Transgenic expression of TLR2 and TLR6 restored responsiveness to phenol soluble modulin and peptidoglycan in IEC. In addition to low levels of TLR2 protein expression, IEC also express high levels of the inhibitory molecule Tollip. We conclude that IEC are broadly unresponsive to TLR2 ligands secondary to deficient expression of TLR2 and TLR6. The relative absence of TLR2 protein expression by IEC and high level of Tollip expression may be important in preventing chronic proinflammatory cytokine secretion in response to commensal Gram-positive bacteria in the gut.
Collapse
Affiliation(s)
- Gil Melmed
- Inflammatory Bowel Disease Center, Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
|
34
|
Abstract
Colonization with bacteria is critical for the normal structural and functional development and optimal function of the mucosal immune system. Unrestrained mucosal immune activation in response to bacterial signals from the lumen is, however, a risk factor for inflammatory bowel disease. Therefore, mucosal immune responses to indigenous flora require precise control and an immunosensory capacity for distinguishing commensals from pathogens. The use of germ-free animal models with selective colonization strategies combined with modern molecular techniques promises to clarify the molecular signals responsible for host-flora interactions in health and disease. At least half of the resident flora cannot be cultured by conventional techniques but are identifiable by molecular methods. Collectively, the resident flora represent a virtual organ with a metabolic activity in excess of the liver and a microbiome in excess of the human genome. An improved understanding of this hidden organ holds secrets relevant to several infectious, inflammatory and neoplastic disease mechanisms.
Collapse
Affiliation(s)
- Fergus Shanahan
- Department of Medicine, University College Cork, National University of Ireland, Cork, Ireland
| |
Collapse
|
35
|
Abreu MT, Taylor KD, Lin YC, Hang T, Gaiennie J, Landers CJ, Vasiliauskas EA, Kam LY, Rojany M, Papadakis KA, Rotter JI, Targan SR, Yang H. Mutations in NOD2 are associated with fibrostenosing disease in patients with Crohn's disease. Gastroenterology 2002; 123:679-88. [PMID: 12198692 DOI: 10.1053/gast.2002.35393] [Citation(s) in RCA: 324] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND & AIMS The clinical manifestations of Crohn's disease (CD) are diverse, ranging from fibrostenosing small-bowel disease to colon-predominant inflammation. These distinctions may represent genetic, immunologic, and microbial heterogeneity. NOD2 gene mutations in CD have been described recently and may alter innate immune responses. We hypothesized that NOD2 mutations may be associated with distinct phenotypic expressions of CD. METHODS Two cohorts of consecutively identified patients referred to an inflammatory bowel disease center (n = 142 collected between 1993 and 1996; n = 59 collected between 1999 and 2001) were genotyped for 3 single nucleotide variants of NOD2-R675W, G881R, and 3020insC-and phenotyped for disease behavior, disease location, and serum immune markers. RESULTS Univariate analysis showed that CD-associated NOD2 variants were significantly associated with fibrostenosing disease in each cohort (P = 0.049 and P = 0.002, respectively). When both cohorts were analyzed together, the association between NOD2 variants and fibrostenosing disease was more significant (P = 0.001). These relationships were observed in both Jews and non-Jews. Forty-six percent of patients with fibrostenosing disease carried at least 1 of these alleles, compared with only 23.5% of patients without fibrostenosing disease (odds ratio, 2.8; 95% confidence interval, 1.6-5.2). Multivariate and conditioning analyses showed a primary association between NOD2 allelic variants and fibrostenosing disease, but not with small-bowel disease. CONCLUSIONS In this description of a genotype/phenotype correlation in CD patients and NOD2 variants, data suggest that variation in this gene contributes to the occurrence of fibrostenotic CD of the small bowel.
Collapse
Affiliation(s)
- Maria T Abreu
- Inflammatory Bowel Disease Center, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Tato CM, Hunter CA. Host-pathogen interactions: subversion and utilization of the NF-kappa B pathway during infection. Infect Immun 2002; 70:3311-7. [PMID: 12065467 PMCID: PMC128040 DOI: 10.1128/iai.70.7.3311-3317.2002] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- C M Tato
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | | |
Collapse
|
37
|
Abreu MT, Arnold ET, Thomas LS, Gonsky R, Zhou Y, Hu B, Arditi M. TLR4 and MD-2 expression is regulated by immune-mediated signals in human intestinal epithelial cells. J Biol Chem 2002; 277:20431-7. [PMID: 11923281 DOI: 10.1074/jbc.m110333200] [Citation(s) in RCA: 295] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The normal intestinal epithelium is not inflamed despite contact with a high density of commensal bacteria. Intestinal epithelial cells (IEC) express low levels of TLR4 and MD-2 and are lipopolysaccharide (LPS)-unresponsive. We hypothesized that immune-mediated signals regulate the expression of TLR4 and MD-2 in IEC. Expression of TLR4 and MD-2 was examined in normal colonic epithelial cells or intestinal epithelial cell lines. The effect of the cytokines interferon (IFN)-gamma, IFN-alpha, and tumor necrosis factor-alpha (TNF-alpha) on TLR4 and MD-2 expression was examined by reverse transcription-PCR and Western blot. NF-kappaB transcriptional activation and interleukin-8 secretion were used as measures of LPS responsiveness. Native colonic epithelial cells and IEC lines express a low level of TLR4 and MD-2 mRNA. IFN-gamma regulates MD-2 expression in both IEC lines, whereas IFN-gamma and TNF-alpha regulate TLR4 mRNA expression in IEC lines. Pre-incubation with IFN-gamma and/or TNF-alpha sensitizes IEC to LPS-dependent interleukin-8 secretion. To examine MD-2 transcriptional regulation, we cloned a 1-kb sequence proximal to the MD-2 gene translational start site. This promoter directed expression of a reporter gene in endothelial cells and IEC. IFN-gamma positively regulated MD-2 promoter activity in IEC. Co-expression of a STAT inhibitor, SOCS3, blocked IFN-gamma-mediated MD-2 promoter activation. T cell-derived cytokines lead to increased expression of TLR4 and MD-2 and LPS-dependent pro-inflammatory cytokine secretion in IEC. IFN-gamma regulates expression of the critical TLR4 co-receptor MD-2 through the Janus tyrosine kinase-STAT pathway. Th1 cytokines may initiate or perpetuate intestinal inflammation by altering toll-like receptor expression and bacterial reactivity.
Collapse
Affiliation(s)
- Maria T Abreu
- Inflammatory Bowel Disease Center, Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.
| | | | | | | | | | | | | |
Collapse
|
38
|
Brandtzaeg PER. Current understanding of gastrointestinal immunoregulation and its relation to food allergy. Ann N Y Acad Sci 2002; 964:13-45. [PMID: 12023193 DOI: 10.1111/j.1749-6632.2002.tb04131.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Tolerance to food antigens induced via the gut ("oral tolerance") appears to be a rather robust adaptive immune mechanism. However, the neonatal period is particularly critical in terms of mucosal defense, with regard to infections and priming for allergic disease. This is so because the intestinal barrier function provided by secretory antibodies, as well as the immunoregulatory network, is poorly developed for a variable period after birth. Notably, the postnatal development of mucosal immune homeostasis depends on the establishment of a normal commensal microbial flora and also on adequate timing and dose of dietary antigens when first introduced. In this context, breastfeeding appears to exert both shielding and positive regulatory effects. Altogether, the intestinal immune system normally seems rather fit for tolerance induction against innocuous antigens because most children with food allergy "outgrow" their problems, whereas airway allergy tends to persist.
Collapse
Affiliation(s)
- P E R Brandtzaeg
- Laboratory for Immunohistochemistry and Immunopathology (LIIPAT), Institute of Pathology, University of Oslo, Rikshospitalet, Norway.
| |
Collapse
|
39
|
Abreu MT, Vora P, Faure E, Thomas LS, Arnold ET, Arditi M. Decreased expression of Toll-like receptor-4 and MD-2 correlates with intestinal epithelial cell protection against dysregulated proinflammatory gene expression in response to bacterial lipopolysaccharide. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:1609-16. [PMID: 11466383 DOI: 10.4049/jimmunol.167.3.1609] [Citation(s) in RCA: 500] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The lumenal surface of the colonic epithelium is continually exposed to Gram-negative commensal bacteria and LPS. Recognition of LPS by Toll-like receptor (TLR)-4 results in proinflammatory gene expression in diverse cell types. Normally, however, commensal bacteria and their components do not elicit an inflammatory response from intestinal epithelial cells (IEC). The aim of this study is to understand the molecular mechanisms by which IEC limit chronic activation in the presence of LPS. Three IEC lines (Caco-2, T84, HT-29) were tested for their ability to activate an NF-kappaB reporter gene in response to purified, protein-free LPS. No IEC line responded to LPS, whereas human dermal microvessel endothelial cells (HMEC) did respond to LPS. IEC responded vigorously to IL-1beta in this assay, demonstrating that the IL-1 receptor signaling pathway shared by TLRs was intact. To determine the reason for LPS hyporesponsiveness in IEC, we examined the expression of TLR4 and MD-2, a critical coreceptor for TLR4 signaling. IEC expressed low levels of TLR4 compared with HMEC and none expressed MD-2. To determine whether the low level of TLR4 expression or absent MD-2 was responsible for the LPS signaling defect in IEC, the TLR4 or MD-2 gene was transiently expressed in IEC lines. Transient transfection of either gene individually was not sufficient to restore LPS signaling, but cotransfection of TLR4 and MD-2 in IEC led to synergistic activation of NF-kappaB and IL-8 reporter genes in response to LPS. We conclude that IEC limit dysregulated LPS signaling by down-regulating expression of MD-2 and TLR4. The remainder of the intracellular LPS signaling pathway is functionally intact.
Collapse
Affiliation(s)
- M T Abreu
- Inflammatory Bowel Disease Center, Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, 8631 West 3rd Street, Los Angeles, CA 90048, USA.
| | | | | | | | | | | |
Collapse
|
40
|
Abstract
Treatment options for inflammatory bowel disease (IBD) reflect a continuing shift from empiricism to strategies based on improved understanding of the pathophysiology of disease. In susceptible individuals, IBD appears to be the result of defective regulation of mucosal immune interactions with the enteric microflora. This has prompted research directed at the interface of the traditional disciplines of immunology, microbiology, and epithelial cell biology. Whereas immunodiagnostics have been of limited clinical value in IBD, assessments of mucosal rather than systemic immune function are promising. Therapeutically, there is an increasing trend toward more aggressive and earlier use of immunomodulatory agents, particularly for prevention of relapse, with cytokine manipulation as a bridge therapy to achieve remission in patients with acute severe disease. Although most drug treatments are directed toward altering the host response, the rationale for manipulating the enteric flora appears sound and will be the basis of additional future therapeutic strategies. Notwithstanding the widening range of options for drug therapy in IBD, other outcome modifiers and well-established principles of managing chronic disease are as important as ever.
Collapse
Affiliation(s)
- F Shanahan
- Department of Medicine, Cork University Hospital and National University of Ireland, Cork, Ireland.
| |
Collapse
|