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Ian R Sanderson

Publications and source records attributed to Ian R Sanderson.

At least 19 recordsLinked to original sources
PubMed2006

TLRs in the Gut I. The role of TLRs/Nods in intestinal development and homeostasis.

The innate immune system includes microbial pattern recognition receptors that detect bacteria and viral products at the cell surface, in vesicles, and within the cytoplasm. Transmembrane signaling occurs through Toll-like receptors (TLRs). Cytoplasmic receptors are generally members of the nucleotide-binding domain (NOD)-leucine-rich repeat (LRR) family (CATERPILLER family). They influence the effects of other family members and of TLRs. Most NOD-LRR members enhance signal transduction, but Monarch-1 counterbalances TLR activity. NOD-LRR family members also act within the adaptive immune system. The class II transactivator regulates major histocompatibility complex class II expression. In the intestine, it is developmentally regulated, and its expression depends on weaning and, independently, on age.

Animals↗
PubMed2006

Helicobacter pylori regulates the expression of inhibitors of DNA binding (Id) proteins by gastric epithelial cells.

Id transcription factors control proliferation, differentiation and apoptosis by inhibiting the DNA binding of basic helix-loop-helix transcription factors. Increased expression of Id proteins promotes proliferation, inhibits differentiation, and is associated with intestinal tumorigenesis. We aimed to determine how Helicobacter pylori may alter the expression of Id proteins by gastric epithelial cells: it was hypothesised that H. pylori, a known carcinogen, would result in increased expression of one or more Id family members. In vitro and in vivo models of infection were employed, including treatment of AGS gastric epithelial cells with wild-type H. pylori strains, 60190 and SS1, and Mongolian gerbils infected with H. pylori SS1. A small cohort of human gastric mucosal biopsies was also examined. Treatment of AGS cells with H. pylori resulted in down-regulation of Id1 and Id3. Unexpectedly, expression of the main target of Id proteins, the basic helix-loop-helix transcription factor E2A, was also suppressed, with an associated decrease in E-box binding activity. In contrast, H. pylori induced the expression of the CDK inhibitor p21(WAF-1/cip1), and the homeobox transcription factor, Cdx2, an early marker of intestinal metaplasia of the stomach epithelium. Gastric epithelium from H. pylori-infected gerbils demonstrated similar changes, with decreased Id2, Id3 and E2A, and elevated p21(WAF-1/cip1) expression. In human gastric epithelium also, H. pylori infection was associated with reduced Id and E2A expression. In conclusion, H. pylori alters the expression of Id proteins, in vitro and in vivo; it is hypothesised that these changes contribute to H. pylori-associated pathologies.

Adolescent↗
PubMed2006

Myofibroblast matrix metalloproteinases activate the neutrophil chemoattractant CXCL7 from intestinal epithelial cells.

BACKGROUND & AIMS: The up-regulation of matrix metalloproteinases (MMPs) in the inflamed gut has mainly been associated with mucosal degradation and ulceration. However, their in vitro capacity to specifically cleave inflammatory mediators indicates that MMPs may have a profound immunoregulatory impact. We hypothesized that MMPs proteolytically modify intestinal epithelial chemokine signaling. METHODS: Interleukin-1beta-stimulated Caco-2 cells were exposed basolaterally to nanomolar concentrations of activated MMP-3 or cocultured with interleukin-1beta-stimulated, MMP-producing, colonic myofibroblasts (CCD-18co). The conditioned media were subjected to chemotaxis assays. In addition, epithelial cells from patients with colitis were examined by real-time polymerase chain reaction, immunoblotting, and immunohistochemistry. RESULTS: MMP-3 dose-dependently induced the neutrophil (up to 5-fold) but not monocyte chemoattractant capacity of Caco-2 cells. A similar Caco-2 chemotactic response was obtained in the Caco-2/CCD-18co cocultures. The principal mediator of these protease-related effects was identified as the potent neutrophil chemokine CXCL7 (neutrophil activating peptide 2), a proteolytic cleavage product of chemotactically inert platelet basic protein (PBP), not previously identified in the intestine. Antibodies against CXCL7 inhibited the MMP-induced chemotactic response by 84%, and PBP mRNA and protein were detected in stimulated Caco-2 but not in CCD-18co cells. Furthermore, PBP transcript and protein levels were low in the mucosa and in isolated epithelial cells from patients with Crohn's disease and from normal intestine but increased up to 13-fold in patients with ulcerative colitis. CONCLUSIONS: These findings identify a novel proinflammatory action of MMPs in inflammation and suggest that lamina propria myofibroblasts are required to achieve maximal intestinal epithelial immune activation.

Caco-2 Cells↗
PubMed2006

Sodium butyrate-mediated Sp3 acetylation represses human insulin-like growth factor binding protein-3 expression in intestinal epithelial cells.

OBJECTIVES: Butyrate concentrations in the gastrointestinal tract vary greatly with age. In intestinal epithelial cells, butyrate enhances gene transcription by increasing histone acetylation, rendering the nucleosome open to transcription factors. However, it inhibits human insulin-like growth factor binding protein (hIGFBP)-3 expression. We therefore hypothesized that butyrate also acts by regulating transcription factor acetylation. METHODS: Gene regulation was examined in Caco-2 cells. RNA stability was measured after interruption of transcription. The activity of deletion mutations of the hIGFBP-3 promoter was examined in reporter assays. Transcription factor binding to promoter DNA was analyzed. RESULTS: Butyrate did not increase the transcription of a repressor because it inhibited hIGFBP-3 mRNA in the absence of protein synthesis. Nor did butyrate decrease the stability of hIGFBP-3 mRNA. Analysis of the hIGFBP-3 promoter demonstrated a butyrate-response element that included the binding sites for p300 and Sp1/Sp3. Transfection of Caco-2 cells with E1A, an inhibitor of p300 acetyltransferase activity, reversed the butyrate-induced repression of hIGFBP-3. Because Sp3 represses the initiation of transcription, we studied whether butyrate induced Sp3 acetylation. Electrophoretic mobility shift assays of nuclei extracted from Caco-2 cells treated with 5 mmol/L butyrate demonstrated an extra, heavier band in addition to the Sp3-DNA binding in untreated cells. This corresponded to a protein, detected only in butyrate treated cells, that was identified both by an anti-Sp3 antibody and by an anti-acetyl lysine antibody. CONCLUSIONS: This study demonstrates that butyrate increases the acetylation of a nonhistone protein, Sp3, catalyzed by p300 acetyltransferase activity.

Acetylation↗
PubMed2006

Breast milk lactoferrin regulates gene expression by binding bacterial DNA CpG motifs but not genomic DNA promoters in model intestinal cells.

High-affinity binding of DNA by lactoferrin (LF) is an established phenomenon, but the biologic function of this interaction remains unclear. LF is an abundant breast milk protein (12.5-87.5 micromol/L) and is resistant to digestion in the infant gut. Regulation of gene expression by LF appears to be a major activity, particularly in modulating immune responses. We hypothesized that LF binding to DNA is a mechanism of gene regulation and aimed to identify the mechanism and physiologic sites of this activity. Our studies focused on two major biologic compartments of DNA: LF binding to proinflammatory bacterial DNA sequences (CpG motifs) in extracellular compartments and LF binding to genomic DNA promoters in the nucleus. LF 0.5 mmol/L inhibited CpG motif-induced nuclear factor-kappaB (NF-kappaB) activation and interleukin (IL)-8 and IL-12 cytokine gene transcription in B cells. Intestinal epithelial cells were unresponsive to CpG motifs. However, significant LF transferred across M cell-like monolayers, specialized epithelial cells that transcytose intact macromolecules to underlying B-cell follicles in the intestine. LF did not activate gene expression by binding to putative response elements in epithelial and lymphoid cells. Nor did LF bind to putative response elements specifically in gel-shift assays. No nuclear localization of LF was detected in green fluorescent protein (GFP) tagging experiments. We conclude that breast milk LF regulates gene expression by binding CpG motifs extracellularly, with follicular B cells in the infant intestine a likely target.

B-Lymphocytes↗
PubMed2006

Clinical features affecting final adult height in patients with pediatric-onset Crohn's disease.

BACKGROUND: Growth failure is a recognized complication of pediatric-onset Crohn's disease, but there are few data on final adult height. OBJECTIVE: Our purpose with this work was to determine adult height and the clinical features that influence long-term growth impairment. METHODS: We retrospectively studied 123 patients with Crohn's disease (65 male and 58 female) who had reached adult height. All of the case subjects were diagnosed before age 16.0 years. Heights were converted to SD scores and univariate analysis performed of factors postulated to influence final height, that is, interval from onset of symptoms to diagnosis, prepubertal onset of symptoms, gender, jejunal disease present at diagnosis, systemic steroid therapy, intestinal surgery, and midparental height SD scores. Significant univariate factors were additional analyzed in regression models. RESULTS: Mean height deficit at diagnosis was -0.50 SD scores, which improved to -0.29 SD scores at final height. Mean final height compared with target height, calculated from parental height, was -2.4 cm (range: -20.0 to 9.0 cm). Nineteen percent of the case subjects achieved a final height >8.0 cm below target height. The length of the interval between symptom onset and diagnosis correlated negatively with height SD scores at diagnosis. Height SD scores at diagnosis were related to final height SD scores, independent of midparental height. The presence of jejunal disease was negatively related to final height. CONCLUSIONS: Mean final adult height showed a modest deficit compared with target height, but in one fifth of patients, final height was significantly less than target height. Earlier diagnosis and improved treatment of jejunal disease would be likely to improve final height.

Adolescent↗
PubMed2005

Intestinal inflammation-induced growth retardation acts through IL-6 in rats and depends on the -174 IL-6 G/C polymorphism in children.

Inflammatory diseases frequently impair linear growth. Crohn's disease inhibits growth in up to one third of affected children. In rats with trinitrobenzenesulphonic acid-induced colitis, 40% of growth impairment is attributable to inflammation, with the rest being due to undernutrition. In transgenic mice without inflammation, raised IL-6 retards growth, suppressing insulin-like growth factor (IGF)-I. We hypothesized that IL-6, induced by intestinal inflammation, suppresses growth and inhibits IGF-I expression. Therefore, an anti-IL-6 Ab was given to rats with trinitrobenzene-sulphonic acid colitis. The Ab did not improve nutrient intake or decrease inflammation compared with untreated disease controls, but it significantly restored linear growth (P = 0.023) and increased IGF-I (P = 0.05). In humans, the IL-6 -174 G/C promoter polymorphism affects IL-6 transcription, with the GG genotype inducing the greatest IL-6 levels. Because IL-6 is increased in Crohn's disease, we further hypothesized that growth failure would vary with the IL-6 -174 genotype. At diagnosis, among 153 children with Crohn's disease, those with the IL-6 GG genotype were more growth-retarded than those with the GC or CC genotypes (height SD score, -0.51 vs. -0.10; P = 0.031). Also, the patients with the IL-6 GG genotype had higher circulating levels of C-reactive protein, an IL-6-induced product (36 vs. 18 mg/dl, P = 0.028). However, their risk of developing Crohn's disease was similar to other genotypes when compared with 351 healthy controls (P = 0.7). Thus, the IL-6 -174 genotype mediates growth failure in children with Crohn's disease.

Animals↗
PubMed2005

Effect of inflammation on cyclooxygenase (COX)-2 expression in benign and malignant oesophageal cells.

Chronic inflammation has been linked to carcinogenesis in various tissue sites. Barrett's oesophageal epithelium (BE) is a premalignant condition in which cyclooxygenase-2 (COX-2) levels are increased. However, it is not clear whether the primary stimulus for the high COX-2 levels is related to inflammation or malignancy. The effect of exogenous cytokines (IL-1beta, IL-10 and IL-13) on COX-2 expression was assessed by western blotting in three BE cancer cell lines (SEG-1, BIC-1 and OE33) and a squamous cancer cell line (OE21). Primary tissue was assessed from 17 patients with long BE segments, 13 oesophagitis, 30 oesophageal adenocarcinoma (EAC), and 40 normal oesophageal (NE) and duodenal (DU) controls. COX-2 protein expression was determined by western blotting and its tissue localization was examined using immunohistochemistry. COX-2 protein and the neutrophil marker myeloperoxidase (MPO) were quantified along BE segments. The leukocyte marker CD45 was used to identify any correlation between COX-2 expression and leukocyte cell distribution in EAC. IL-1beta induced COX-2 expression in SEG-1 cells (P < 0.05), whereas IL-10 and IL-13 had no effect. COX-2 protein levels were found to be increased in distal BE > proximal BE > oesophagitis > NE (P < 0.001). COX-2 expression in EAC was heterogeneous and the overall levels were not significantly increased. The increased COX-2 expression in distal BE was not associated with inflammation (MPO expression). In addition, there was no correlation between COX-2 and CD45 in AC. COX-2 protein expression in the oesophagus appears to be independent of the degree of inflammation.

Adenocarcinoma↗
PubMed2005

Markers to measure immunomodulation in human nutrition intervention studies.

Normal functioning of the immune system is crucial to the health of man, and diet is one of the major exogenous factors modulating individual immunocompetence. Recently, nutrition research has focused on the role of foods or specific food components in enhancing immune system responsiveness to challenges and thereby improving health and reducing disease risks. Assessing diet-induced changes of immune function, however, requires a thorough methodological approach targeting a large spectrum of immune system parameters. Currently, no single marker is available to predict the outcome of a dietary intervention on the resistance to infection or to other immune system-related diseases. The present review summarises the immune function assays commonly used as markers in human intervention studies and evaluates their biological relevance (e.g. known correlation with clinically relevant endpoints), sensitivity (e.g. within- and between-subject variation), and practical feasibility. Based on these criteria markers were classified into three categories with high, medium or low suitability. Vaccine-specific serum antibody production, delayed-type hypersensitivity response, vaccine-specific or total secretory IgA in saliva and the response to attenuated pathogens, were classified as markers with high suitability. Markers with medium suitability include natural killer cell cytotoxicity, oxidative burst of phagocytes, lymphocyte proliferation and the cytokine pattern produced by activated immune cells. Since no single marker allows conclusions to be drawn about the modulation of the whole immune system, except for the clinical outcome of infection itself, combining markers with high and medium suitability is currently the best approach to measure immunomodulation in human nutrition intervention studies. It would be valuable to include several immune markers in addition to clinical outcome in future clinical trials in this area, as there is too little evidence that correlates markers with global health improvement.

Aging↗
PubMed2005

Immunology.

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Animals↗
PubMed2004

Gastrin-induced cyclooxygenase-2 expression in Barrett's carcinogenesis.

PURPOSE: Cyclooxygenase (COX)-2 has been causally implicated in carcinogenesis. The evidence for increased COX-2 in the malignant progression of Barrett's esophagus is contradictory. We hypothesize that COX-2 expression may be causally affected by the gastrin status via the cholecystokinin 2 (CCK(2)) receptor. EXPERIMENTAL DESIGN: COX-2 and prostaglandin E(2) expression were evaluated by Western blotting and enzyme-linked immune assay in samples of squamous esophagus, Barrett's esophagus with varying degrees of dysplasia to adenocarcinoma, and normal duodenum. Differentiation status was evaluated by histopathology and villin expression. A longitudinal case-control study compared COX-2 in patients who progressed to adenocarcinoma with nonprogressors matched for age and length of follow-up. Messenger RNA levels of gastrin and CCK(2) receptor in biopsies and cell lines were evaluated by reverse transcription-PCR, and in vitro gastrin stimulation was conducted with and without inhibitors for CCK(2) (YM022) and COX-2 (NS-398). Cell proliferation was evaluated using minichromosome maintenance protein 2 (Mcm2) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays. RESULTS: COX-2 expression is significantly increased in Barrett's esophagus before dysplasia development. Expression is highly variable within Barrett's dysplasia and adenocarcinoma samples independent of differentiation status. In a longitudinal case-control study, the expression levels within patients increased over time, regardless of the degree of malignant progression. Biopsies from nondysplastic Barrett's esophagus expressed increased gastrin mRNA levels compared with other biopsies. Gastrin significantly induced COX-2, prostaglandin E(2), and cell proliferation in biopsies and cell lines. Gastrin-induced proliferation can be inhibited by YM022 and NS-398. CONCLUSIONS: COX-2 is up-regulated early in the Barrett's metaplasia sequence. During carcinogenesis, gastrin is a significant determinant of COX-2 activity levels via the CCK(2) receptor.

Adenocarcinoma↗
PubMed2004

Diarrhoea in children: an interface between developing and developed countries.

Despite much progress in the understanding of pathogenesis and of management, diarrhoeal illnesses remain one of the most important causes of global childhood mortality and morbidity. Infections account for most illnesses, with pathogens employing ingenious mechanisms to establish disease. In the developed world, an upsurge in immune-mediated gut disorders might have resulted from a disruption of normal bacterial-epithelial cross-talk and impaired maturation of the gut's immune system. Oral rehydration therapies are the mainstay of management of gastroenteritis, and their composition continues to improve. Malnutrition remains the major adverse prognostic indicator for diarrhoea-related mortality, emphasising the importance of nutrition in early management. Drugs are of little use, except for specific indications although new agents that target mechanisms of secretory diarrhoea show promise, as do probiotics. However, preventive strategies on a global scale might ultimately hold the greatest potential to reduce the burden of diarrhoeal disease. These strategies include vaccines and, most importantly, policies to address persisting inequalities between the developed and developing worlds with respect to nutrition, sanitation, and access to safe drinking water.

Child↗
PubMed2004

The effect of specific caspase inhibitors on TNF-alpha and butyrate-induced apoptosis of intestinal epithelial cells.

Tumour necrosis factor-alpha (TNF-alpha)-induced intestinal epithelial cell apoptosis may contribute to mucosal injury in inflammatory bowel disease. Inhibition of TNF-alpha-induced apoptosis, using specific caspase inhibitors could, therefore, be of benefit in the treatment of disease. In vitro, CaCo-2 colonic epithelial cells are refractory to apoptosis induced by TNF-alpha alone; however, TNF-alpha can act synergistically with the short-chain fatty acid (SCFA) and colonic fermentation product, butyrate, to promote apoptosis. TNF-alpha/butyrate-induced apoptosis was characterised by nuclear condensation and fragmentation and caspase-3 activation. Inhibitors of caspase-8 (z-IETD.fmk) and caspase-10 (z-AEVD.fmk) significantly reduced TNF-alpha/butyrate-induced apoptosis, based on nuclear morphology and terminal deoxynucleotide transferase-mediated dUTP-biotin nick-end labelling (TUNEL), although caspase inhibition was associated with a significant increase in cells demonstrating atypical nuclear condensation. Inclusion of atypical cells in calculations of total cell death, still demonstrated that z-IETD.fmk and z-AEVD.fmk (in combination) significantly reduced cell death. Reduction in cell death was associated with maintenance of viable cell number. Transmembrane resistance was also used a measure of the ability of caspase inhibitors to prevent TNF-alpha/butyrate-mediated damage to epithelial monolayers. TNF-alpha/butyrate resulted in a significant fall in transmembrane resistance, which was prevented by pre-treatment with z-IETD.fmk, but not z-AEVD.fmk. In conclusion, synthetic caspase inhibitors can reduce the apoptotic response of CaCo-2 colonic epithelial cells to TNF-alpha/butyrate, improve the maintenance of viable cell numbers and block loss of transmembrane resistance. We hypothesise that caspase inhibition could be a useful therapeutic goal in the treatment of inflammatory bowel conditions, such as ulcerative colitis.

Apoptosis↗
PubMed2004

Age and diet act through distinct isoforms of the class II transactivator gene in mouse intestinal epithelium.

BACKGROUND & AIMS: Normal weaning induces class II major histocompatibility complex (Ia) and invariant chain (Ii) expression in the mouse intestinal epithelium. Because the class II transactivator protein (CIITA) induces Ia and Ii in most cell types, we hypothesized that diet-induced expression of these genes was through CIITA. METHODS: Mouse litters were split and weaned onto an elemental diet or a normal (complex) chow diet. On days 24, 31, and 45, epithelial cells were isolated from small intestine with EDTA, and the RNA was extracted from both wild-type and interferon (IFN)-gamma receptor knockout mice. Messenger RNA (mRNA) was measured by Northern blotting, RNase protection assay, and real-time polymerase chain reaction and Ia localized by immunohistochemistry. RESULTS: By day 31, CIITA mRNA was induced in the intestinal epithelium of normally weaned wild-type mice, and this mirrored the expression of Ii chain mRNA. Mice weaned onto an elemental diet did not exhibit Ii mRNA or increased CIITA mRNA in the intestinal epithelium by day 31, but low levels of Ii mRNA were detectable by day 45. Of the 3 isoforms of CIITA, weaning onto a complex diet induced only CIITA IV by day 31. Mice deficient in the IFN-gamma receptor expressed Ia in the epithelium and they also accumulated Ii mRNA (at low levels) by day 45, irrespective of diet. CIITA III mRNA accumulation mirrored the dietary-independent changes of Ii mRNA. CONCLUSIONS: Two mechanisms regulate Ii in the mouse intestinal epithelium: a rapid one, which is diet-induced acting through CIITA IV; and a slower, dietary-independent pathway, acting through CIITA III.

Age Factors↗
PubMed2004

Short chain fatty acid regulation of signaling genes expressed by the intestinal epithelium.

Changes in diet greatly affect the mucosal immune system, particularly in diseases such as Crohn's disease and necrotizing enterocolitis. This review examines the hypothesis that alterations in the luminal environment of the intestine regulate the expression of genes in the epithelium responsible for signaling to immune cells. Increasing chemokine expression in the mouse intestinal epithelium using transgenic techniques enhances the recruitment of neutrophils and lymphocytes into the intestine. Furthermore, SCFA concentrations in the intestinal lumen vary markedly with diet. SCFAs alter chemokine expression by inhibiting histone deacetylase activity in the enterocyte. The review therefore describes a molecular pathway explaining how changes in diet may alter leukocyte recruitment by regulating enterocyte gene expression. It is likely that other similar pathways remain to be discovered.

Animals↗
PubMed2004

Anti-inflammatory and growth-stimulating effects precede nutritional restitution during enteral feeding in Crohn disease.

OBJECTIVES: Exclusive enteral feeding reduces inflammation and improves well being, nutrition and growth in children with active Crohn disease. Whether improved growth and increases in growth-related proteins are a consequence of improved nutrition or a reduced inflammation is not known. This study was undertaken to test the hypothesis that changes in growth-related proteins are related to decreased inflammation, rather than improvement in nutritional status. METHODS: Twelve children with active Crohn disease treated for 6-weeks with exclusive enteral feeding were studied at days 0, 3, 7, 14, 21, 28, and 56. The Paediatric Crohn's Disease Activity Index (PCDAI), weight, triceps skinfold thickness, and midupper arm circumference were recorded. C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), interleukin-6 (IL-6), insulin-like growth factor (IGF-I), IGF-binding protein (IGFBP-3), and leptin were measured at each visit. Wilcoxon matched-pairs signed-rank test was used to compare day 0 with follow-up data. RESULTS: Significant improvements (P < 0.05) occurred by day 3 in inflammatory parameters (ESR, IL-6) and by day 7 in PCDAI, CRP, and IGF-I. These changes preceded any significant changes in nutritional parameters (weight-for-age Z score and midupper arm circumference day 14, triceps skinfold thickness day 21). CONCLUSIONS: Early increases in IGF-I during treatment of Crohn disease are attributable to the anti-inflammatory effect of the enteral feed rather than nutritional restitution.

Adolescent↗