Circadian regulation of CREB transcription factor in mouse esophagus

Analysis of Somatostatin-Secreting Gastric Delta Cells according to Upper Abdominal Symptoms and Helicobacter pylori Infection in Children

PURPOSE

Gastric delta cells (D-cells), which are somatostatin-secreting cells, are the main paracrine inhibitor of acid secretion. The number of D-cells was studied in children presenting with upper gastrointestinal (UGI) disease.

METHODS

We retrospectively investigated the number of D-cells in the gastric body and antrum through immunofluorescence examinations according to symptoms, endoscopic findings, and Helicobacter pylori infection in 75 children who visited Hanyang University Hospital Pediatrics.

RESULTS

The mean patient age was 12.2±3.3 years. The male-to-female ratio was 1:1.4. The mean D-cell number per high-power field in the antrum and body was 20.5 and 12 in children with substernal pain, 18.3 and 10.3 in vomiting, 22.3 and 6 in diarrhea, and 9.3 and 6 in abdominal pain, respectively (p>0.05). According to endoscopic findings, the mean D-cell number in the antrum and body was 14.3 and 6 with gastritis, 14 and 9.3 with reflux esophagitis, 16.7 and 8.7 with duodeno-gastric reflux, 19.3 and 12.7 with gastric ulcer, 16 and 13.7 with duodenitis, and 12.3 and 4 with duodenal ulcer, respectively (p>0.05). The D-cell number in the gastric body was 2.7 and 8.7 in children with current H. pylori infection and non-infected children, respectively (p=0.01), while those in the antrum were 15.5 and 14, respectively, with no statistical significance.

CONCLUSION

The D-cell number was lower in the gastric body of children with current H. pylori infection. Further studies concerning peptide-secreting cells with a control group would provide information about the pathogenic pathways of UGI disorder.

Drosophila CrebB is a Substrate of the Nonsense-Mediated mRNA Decay Pathway that Sustains Circadian Behaviors

Post-transcriptional regulation underlies the circadian control of gene expression and animal behaviors. However, the role of mRNA surveillance via the nonsense-mediated mRNA decay (NMD) pathway in circadian rhythms remains elusive. Here, we report that Drosophila NMD pathway acts in a subset of circadian pacemaker neurons to maintain robust 24 h rhythms of free-running locomotor activity. RNA interference-mediated depletion of key NMD factors in timeless-expressing clock cells decreased the amplitude of circadian locomotor behaviors. Transgenic manipulation of the NMD pathway in clock neurons expressing a neuropeptide PIGMENT-DISPERSING FACTOR (PDF) was sufficient to dampen or lengthen free-running locomotor rhythms. Confocal imaging of a transgenic NMD reporter revealed that arrhythmic Clock mutants exhibited stronger NMD activity in PDF-expressing neurons than wild-type. We further found that hypomorphic mutations in Suppressor with morphogenetic effect on genitalia 5 (Smg5 ) or Smg6 impaired circadian behaviors. These NMD mutants normally developed PDF-expressing clock neurons and displayed daily oscillations in the transcript levels of core clock genes. By contrast, the loss of Smg5 or Smg6 function affected the relative transcript levels of cAMP response element-binding protein B (CrebB ) in an isoform-specific manner. Moreover, the overexpression of a transcriptional repressor form of CrebB rescued free-running locomotor rhythms in Smg5-depleted flies. These data demonstrate that CrebB is a rate-limiting substrate of the genetic NMD pathway important for the behavioral output of circadian clocks in Drosophila.

Tablet and oral liquid L-thyroxine formulation in the treatment of naïve hypothyroid patients with Helicobacter pylori infection

To compare the clinical efficacy of tablet and oral liquid L-thyroxine (LT4) formulation in naïve hypothyroid subjects with Helicobacter pylori infection. Forty-seven adult naïve hypothyroid subjects with dyspeptic symptoms were investigated with upper endoscopy and divided into: 28 patients with Helicobacter pylori infection (Group A); 15 patients without gastric alterations (group B); 4 patients with autoimmune gastritis were excluded from the study. Subjects were randomly treated with a same dose of LT4 tablet (TAB) or oral liquid formulation (SOL), for 9 months on group A and 6 months on group B. Helicobacter pylori infection was eradicated after 3 months of LT4 treatment. On group A, after 3 months (before Helicobacter pylori eradication), subjects treated with SOL showed a greater thyroid-stimulating hormone reduction (ΔTSH_3-0: TAB = -4.1 ± 4.6 mU/L; SOL = -7.7 ± 2.5 mU/L; p = 0.029) and a greater homogeneity in the thyroid-stimulating hormone values (TSH_3mo: TAB = 5.7 ± 4.9 mU/L; SOL = 4.1 ± 2.0 mU/L; p = 0.025), compared to LT4 tablet. At 9 months (after 6 months of Helicobacter pylori eradication) mean thyroid-stimulating hormone values were lower in subjects treated with LT4 tablet (TSH_9mo: TAB = 1.8 ± 1.2 mU/L; SOL = 3.2 ± 1.7 mU/L; p = 0.006). On group B no difference were observed, at each time point, in the mean thyroid-stimulating hormone values and thyroid-stimulating hormone variations between two LT4 formulations. LT4 liquid formulation may produce a better clinical response compared to the tablet formulation in hypothyroid subjects with Helicobacter pylori infection.

Rhythmic profiles of cell cycle and circadian clock gene transcripts in mice: a possible association between two periodic systems

The circadian system shapes the rhythms of most biological functions. The regulation of the cell cycle by a circadian clock was suggested to operate via stages S, G2 and G2/M. This study investigated a possible time link at stages G1 and G1/S as well. The daily expression profiles of cell cycle markers (Ccnd1, Ccne1 and Pcna) and circadian clock genes (Per2 and Clock) were monitored in liver and esophagus (low and high proliferation index, respectively) of BALB/c mice. Locomotor activity displayed a 24 h rhythm, establishing the circadian organization of the suprachiasmatic nucleus. In the liver, the mRNA level of Per2 and Clock fitted the circadian rhythm with a 7.5 h shift. This temporal pattern suggests that the liver harbors a functional circadian clock. The rhythm of the analyzed cell cycle genes, however, was of low significance fitness and showed an opposite peak time between Pcna and Clock. These results indicate a weak regulatory role of the circadian clock. In the esophagus, the rhythms of Clock and Per2 mRNA had a similar peak time and non-circadian periods. These results suggest either that the esophagus does not harbor a functional circadian apparatus or that the phenotypes stem from differences in phase and amplitude of the rhythms of its various cell types. The similarity in the rhythm parameters of Clock, Ccne1 and Pcna transcripts questions the control of the circadian clock on the cell cycle along the G1 and G1/S stages. Yet the G1/S transition may play a role in modulating the local clock of proliferating tissues.

The effect of food intake on gene expression in human peripheral blood

Human gene expression traits have been shown to be dependent on gender, age and time of day in blood and other tissues. However, other factors that may impact gene expression have not been systematically explored. For example, in studies linking blood gene expression to obesity related traits, whether the fasted or fed state will be the most informative is an open question. Here, we employed a two-arm cross-over design to perform a genome-wide survey of gene expression in human peripheral blood to address explicitly this type of question. We were able to distinguish expression changes due to individual and time-specific effects from those due to food intake. We demonstrate that the transcriptional response to food intake is robust by constructing a classifier from the gene expression traits with >90% accuracy classifying individuals as being in the fasted or fed state. Gene expression traits that were best able to discriminate the fasted and fed states were more heritable and achieved greater coherence with respect to pathways associated with metabolic traits. The connectivity structure among gene expression traits was explored in the context of coexpression networks. Changes in the connectivity structure were observed between the fasted and fed states. We demonstrate that differential expression and differential connectivity are two complementary ways to characterize changes between fasted and fed states. Both gene sets were significantly enriched for genes associated with obesity related traits. Our results suggest that the pair of fasted/fed blood expression profiles provide more comprehensive information about an individual's metabolic states.

Sequence and expression analysis of the gene encoding inducible cAMP early repressor in tilapia

Suppression subtractive hybridization library was generated by comparison of cDNA populations isolated from peripheral leukocytes of pre- and post-immunized tilapia. One cDNA sequence encoding complete inducible cAMP early repressor was obtained from the library. The sequence was characterized by the presence of the basic structure of ICER IIgamma. Expression of ICER was in the tissues of four types of tilapia was decreased after infection with Streptococcus. After immunization, expression of ICER was initially decreased and then increased after 7 days. In addition, the order for the overall expression of ICER gene after infection and the increases of ICER expression later after immunization in these four types of tilapia was positively correlated to the disease resistance and productivity of these four species of tilapia. Our results provided molecular mechanisms for the different disease resistance capability in different species of tilapia. In addition, our results also provided reference molecular marker for breeding disease resistant tilapia, cAMP responsive element modulator.

Esophageal stem cells--a review of their identification and characterization

The incidence of adenocarcinoma of the esophagus has increased faster than any other internal malignancy over the last 40 years. Despite this, surprisingly little is known about the basic biology of this tissue, particularly with regards to the organization of cell proliferation within the epithelium. This is a matter of crucial importance for our understanding of the pathogenesis of esophageal cancer. Nevertheless, significant advances have recently been made in the identification and functional characterization of both murine and human esophageal stem cells and their progeny in recent years. This places investigators in an exciting position to gain further insights into the processes of tissue renewal and repair on the one hand and the development of dysplasia and malignancy on the other.

Association between reflux esophagitis and/or hiatus hernia and gastric mucosal atrophy level in Japan

BACKGROUND AND AIMS

The mechanisms involved in reflux esophagitis (RE) are mainly esophageal motor dysfunction and abnormal esophageal acid exposure. Therefore the extent of gastric mucosal atrophy (GMA), which is related to gastric acid secretion, is an important factor in the development of RE. The aim of this study was to evaluate the prevalence of RE and hiatus hernia (HH) according to level of GMA.

METHODS

A total of 1897 prospective, consecutive endoscopic examinations were performed by the same endoscopist to investigate the prevalence of RE and HH in patients with closed or open-type GMA. The patients were divided into four age groups: under 44, 45-54, 55-64 and over 65 years.

RESULTS

The prevalence of RE and HH in patients with closed-type GMA was significantly higher than that of open-type GMA in the 45-54, 55-64 and over 65 age groups. In patients with open-type GMA, the prevalence of RE in each age group was similar at 5.0-7.4%, and the prevalence of HH in the over 65 age group was significantly higher than that of the 55-64 age group. In patients with closed-type GMA, the prevalence of RE and HH in the over 65 age group was significantly higher than that of other age groups.

CONCLUSIONS

The existence of closed-type GMA and age over 65 years were important factors in the development of RE and HH.

Helicobacter pylori and CagA seropositivity and its association with gastric and oesophageal carcinoma

OBJECTIVE

Helicobacter pylori infection is an established risk factor for non-cardia gastric adenocarcinoma. Infection with H. pylori strains harbouring the cagA pathology island may augment this association. H. pylori infection may at the same time reduce the risk for oesophageal carcinoma. However, prospective data on the association between CagA seropositivity and gastric or oesophageal carcinomas are limited. The purpose of this study was to investigate whether CagA seropositivity among H. pylori seropositive subjects is associated with gastric or oesophageal carcinomas.

MATERIAL AND METHODS

A nested case-control study was performed in the Malmö Preventive Medicine cohort consisting of 32,906 middle-aged subjects. Tumour cases were identified by the Swedish National Cancer Registry. The Western blot method Helicoblot 2.1 was used to detect H. pylori and CagA seropositivity.

RESULTS

Non-cardia gastric adenocarcinoma was associated with H. pylori seropositivity, odds ratio 17.8 (95% CI: 4.2-74.8; 67 cases). The odds ratio for CagA seropositivity among H. pylori seropositive subjects was 9.7 (95% CI: 1.5-infinity). No significant associations were found between cardia gastric adenocarcinoma and H. pylori or CagA seropositivity among H. pylori seropositive subjects; odds ratios were 1.5 (95% CI: 0.51-4.8) and 2.7 (95% CI: 0.38-infinity), respectively (24 cases). Oesophageal adenocarcinoma and oesophageal squamous cell carcinoma were not significantly associated with H. pylori seropositivity or with CagA seropositivity among H. pylori seropositive subjects; the odds ratios associated with oesophageal adenocarcinoma were 0.46 (95% CI: 0.07-2.6) and 0.38 (95% CI: 0.02-24), respectively. Corresponding odds ratios for oesophageal squamous cell carcinoma were 0.44 (95% CI: 0.15-1.2; 37 cases) and 2.0 (95% CI: 0.24-infinity), respectively.

CONCLUSIONS

CagA seropositivity among H. pylori seropositive subjects is a risk factor for non-cardia gastric adenocarcinoma.

Systems analysis of circadian time-dependent neuronal epidermal growth factor receptor signaling

BACKGROUND

Identifying the gene regulatory networks governing physiological signal integration remains an important challenge in circadian biology. Epidermal growth factor receptor (EGFR) has been implicated in circadian function and is expressed in the suprachiasmatic nuclei (SCN), the core circadian pacemaker. The transcription networks downstream of EGFR in the SCN are unknown but, by analogy to other SCN inputs, we expect the response to EGFR activation to depend on circadian timing.

RESULTS

We have undertaken a systems-level analysis of EGFR circadian time-dependent signaling in the SCN. We collected gene-expression profiles to study how the SCN response to EGFR activation depends on circadian timing. Mixed-model analysis of variance (ANOVA) was employed to identify genes with circadian time-dependent EGFR regulation. The expression data were integrated with transcription-factor binding predictions through gene group enrichment analyses to generate robust hypotheses about transcription-factors responsible for the circadian phase-dependent EGFR responses.

CONCLUSION

The analysis results suggest that the transcriptional response to EGFR signaling in the SCN may be partly mediated by established transcription-factors regulated via EGFR transcription-factors (AP1, Ets1, C/EBP), transcription-factors involved in circadian clock entrainment (CREB), and by core clock transcription-factors (Ror alpha). Quantitative real-time PCR measurements of several transcription-factor expression levels support a model in which circadian time-dependent EGFR responses are partly achieved by circadian regulation of upstream signaling components. Our study suggests an important role for EGFR signaling in SCN function and provides an example for gaining physiological insights through systems-level analysis.

Identification of candidate murine esophageal stem cells using a combination of cell kinetic studies and cell surface markers

The identification and characterization of esophageal stem cells are critical to our understanding of the biology of the esophageal epithelium in health and disease. However, the proliferative compartment within the mouse esophageal epithelium remains poorly characterized. Here, we report that the basal cells of the mouse esophagus can be separated into three phenotypically and functionally distinct subpopulations based on the expression of alpha(6) integrin and transferrin receptor (CD71). Cells that express high levels of alpha(6) integrin and low levels of CD71, termed alpha(6)(bri)CD71(dim), are a minor subpopulation of small and undifferentiated cells that are enriched for label-retaining cells and thus represent a putative esophageal stem cell population. Conversely, cells expressing high levels of both alpha(6) integrin and CD71 (alpha(6)(bri)CD71(bri)), the majority of basal esophageal cells, are enriched for actively cycling cells and therefore represent a transit-amplifying population. Kinetic analyses revealed that a third cell population, which is alpha(6) integrin-dim and CD71-bright (alpha(6)(dim)), is destined to leave the basal layer and differentiate.

Helicobacter pylori infection in children and adults: a single pathogen but a different pathology

BACKGROUND

The aims of this retrospective study were to ascertain in large series of children and adults: the relationship of the infecting strain to gastric mucosal lesions; and the relationship of the infecting strain to its duodenal localization.

MATERIALS AND METHODS

We studied 307 and 604 consecutive children and adults. In gastric mucosal samples H. pylori was cultured, genotyped and histologically assessed, while inflammation, activity and intestinal metaplasia were graded. In a subset of 171 patients H. pylori ureaseA (ureA) and cagA genes were amplified (PCR) using mucosal biopsies from the duodenum.

RESULTS

H. pylori infection was diagnosed in 40 children and 308 adults. cagA was identified in 50% and 65.5% of infected children and adults. Antral activity was associated with the density of infecting bacteria (p <.001) and with cagA (p <.01). Intestinal metaplasia was correlated with cagA (p <.001). The ureA gene was found in 56 duodenal samples from 82 H. pylori positive patients. Duodenal H. pylori ureA was significantly more frequent in patients with duodenal diseases than in those without (p <.01), cagA positive strains being mainly involved in the infection of this anatomical area (p <.01).

CONCLUSIONS

A severe H. pylori-associated gastritis is more prevalent when the density of infecting bacteria is high and when cagA positive strains cause the infection. The most virulent cagA positive H. pylori colonizes not only the gastric, but also the duodenal mucosa, which can be directly damaged by the bacteria itself or by its products.

Trends in reported adenocarcinomas of the oesophagus and gastric cardia in Japan

Adenocarcinomas involving the oesophagus and gastric cardia are becoming more common in Western countries, but data from Japan are limited. We sought to determine whether the frequency of these cancers in Japan has increased in recent decades. Review of national cancer mortality data, national registries of oesophageal and gastric cancer cases, and records from two large cancer centres for various time periods between 1950 and 1998 did not show increased reporting of oesophageal adenocarcinomas. In contrast, both national and cancer centre data indicate an absolute increase in the number of gastric cancers involving the C-area (proximal third of the stomach). From a national registry of resected primary gastric cancer cases, those arising in the C-area as a proportion of all tumours rose by 41.8% between 1963 (12.2% of all registered cases) and 1990 (17.3%). Analysis of true cardia (<2 cm distal to oesophagus-cardia junction) early cancers from the two cancer centres showed significant increases in both absolute number and in proportion to other gastric cancers over a 36-year period. These data suggest that the frequency of cardia cancers is increasing in Japan. Lack of a parallel increase in oesophageal adenocarcinomas could be due to misclassification artefacts and/or coding preferences for gastro-oesophageal junction tumours.

Influence of Helicobacter pylori infection on the prevalence of reflux esophagitis in Japanese patients

BACKGROUND AND AIM

Reflux esophagitis is caused by esophageal motor dysfunction in patients with sufficient gastric acid secretion. Helicobacter pylori causes atrophic gastritis and influences gastric acid secretion. Hiatus hernia (HH) of the esophagus causes motor dysfunction in the lower esophagus. Therefore, this study aimed to test whether H. pylori infection, gastric mucosal atrophy and HH are predictive factors for reflux esophagitis.

METHODS

Helicobacter pylori infection was examined in 781 patients by the measurement of serum immunoglobulin (Ig)G antibody, bacteriological culture and histological examination of biopsy specimens. The prevalence of HH, endoscopically identified gastric mucosal atrophy (closed- or open-type) and reflux esophagitis were investigated by reviewing endoscopic films. Investigated patients were divided into three age groups, under 49, 50-69, and over 70 years. The prevalence of esophagitis, H. pylori infection, gastric mucosal atrophy, and HH were compared to identify the possible predictive factors for reflux esophagitis by using logistic regression analysis.

RESULTS

Sixty-nine patients with reflux esophagitis were found among the 781 investigated cases. The odds ratios of negative H. pylori infection, endoscopically identified closed-type gastric mucosal atrophy, and HH for the prevalence of reflux esophagitis were 1.342, 1.751 and 5.527, respectively. These results indicated that the presence of H. pylori infection was only a weak negative risk factor, and that HH was the most reliable endoscopic predictive factor for reflux esophagitis.

CONCLUSION

Helicobacter pylori infection is a weak negative risk factor for the prevalence of reflux esophagitis, while HH is the most reliable predictive factor.

Biological clocks and the digestive system

Circadian rhythms play a major role in regulating the digestive systems of many organisms. Cell proliferation, migration, differentiation, and even structure vary as a function of time of day in many different digestive organs (i.e., stomach, gut, liver, and pancreas) and cell types, resulting in regionally specific temporal variations in protein and gene expression. Feeding and light set the hands of the digestive clock(s). However, the clockwork has a genetic basis. During the last 10 years, new developments have emerged in our understanding of how cells keep time. Surprisingly, clock genes in mammals are expressed not only in specialized time keepers in the brain, but also in peripheral organs, suggesting that the ability to keep time may also belong to cells within the digestive system. This article reviews several classic examples of circadian variation in the digestive system, with an emphasis on rhythms in cell proliferation, function, and structure. It also briefly summarizes several new ideas about how cells in the brain and possibly the digestive system keep time.

Is Helicobacter pylori eradication associated with gastroesophageal reflux disease?

OBJECTIVES

A recent report has suggested an association between Helicobacter pylori eradication and the development of gastroesophageal reflux disease (GERD). We therefore assessed the incidence of GERD among comparable patients having undergone successful versus failed H. pylori eradication in a controlled trial. We also compared the H. pylori strains in the subjects that developed GERD to those that did not.

METHODS

Patients with a history of proven duodenal ulcer and H. pylori infection were randomised into a H. pylori eradication study. Patients subsequently underwent gastroscopy with gastric biopsies every 3 months for 1 yr. At each visit, the presence of GERD symptoms and endoscopic esophagitis were noted, and the incidence of these variables among patients in whom H. pylori eradication was successful was compared to those in whom it was not. In a subgroup, the presence of the cagA, cagE, and vacA genotypes and of cagA antibodies were determined.

RESULTS

Of 98 patients randomized into this study, 11 dropped out before determination of H. pylori eradication, leaving 87 patients with analyzable results. H. pylori eradication was successful in 63 (72%). By the end of the follow-up period, patients with GERD symptoms or endoscopic esophagitis were more prevalent in the successful than in the failed eradication group (37% [95% CI: 25-50%] vs 13% [95% CI: 3-32%], p = 0.04, 95% CI for the difference: 6-42%), as were patients with GERD symptoms alone (29% [95% CI: 18-41%] vs 8% [95% CI: 1-27%], p = 0.04, 95% CI for the difference: 4-36%) or esophagitis alone (21% [95% CI: 12-33%] vs 4% [95% CI: 0-21%], p = 0.10, 95% CI for the difference: 4-29%, respectively). Multivariate analysis revealed no significant association between the incidence of symptoms or esophagitis and age, gender, Quetelet index, caffeine or alcohol intake, smoking, weight change, or the presence of a hiatus hernia. There were also no differences in the prevalence of H. pylori genotypes from patients who developed GERD as compared to those who did not.

CONCLUSIONS

In this patient population, the incidence of new GERD-type symptoms or endoscopic esophagitis was greater in patients in whom successful eradication was achieved. This difference does not appear to be attributable to weight gain, habits, or specific H. pylori strains.

Circadian regulation of uroguanylin and guanylin in the rat intestine

Uroguanylin (UGN) and guanylin (GN) are the endogenous intestinal ligands for guanylyl cyclase C (GC-C). We examined the circadian expression of UGN, GN, and GC-C in the jejunum, ileum, and proximal colon of young adult rats by Northern blot analyses. These assays revealed that UGN is more abundant in the proximal small intestine, whereas GN and GC-C are more abundant in the proximal colon. mRNA levels showed significant circadian variation for UGN (3- to 18-fold peak/trough difference), GN (2.1- to 2.8-fold peak/trough difference), and GC-C (3- to 5-fold peak/trough difference). The maximal abundance occurred in the dark period for all three mRNAs, although peak UGN and GN expression occurred later in the dark period in the jejunum relative to the ileum and colon. Immunoblot analyses using monospecific polyclonal antibodies against UGN and GN prohormones confirmed the regional and circadian variation detected by Northern assays. Thus the expression of these genes is regulated not only by histological position but also by circadian time.

Regulation of intestinal tyrosine phosphorylation and programmed cell death by peroxovanadate

Cell suspensions of ileal mucosa undergo a rapid and synchronized form of programmed cell death when cultured in a simple medium at 37 degrees C. Because tyrosine phosphorylation of proteins plays a crucial role in the signal transduction of many cellular processes, we examined its role in intestinal programmed cell death by use of immunoblot and immunohistochemical methods. We observed a 50-70% reduction in tyrosine phosphorylation during the initial 10 min of intestinal epithelial cell culture. We hypothesized that the inhibition of protein tyrosine phosphatases would increase protein tyrosine phosphorylation in these suspensions and decrease programmed cell death. A strong inhibitor of these phosphatases (peroxovanadate) but not a weaker one (sodium orthovanadate) abolished the DNA fragmentation/laddering normally seen in dying enterocytes. Peroxovanadate enhanced protein tyrosine phosphorylation of many intestinal proteins, dramatically increasing the dually phosphorylated and active form of mitogen-activated protein kinase. Immunohistochemistry revealed a particularly high level of increased tyrosine phosphorylation in the intestinal crypts in peroxovanadate-treated mucosa. Kinetic studies indicated that the pivotal time for protein tyrosine phosphatase inhibition occurred within 5 min of ex vivo culture, precisely when protein tyrosine phosphorylation declined. Our data suggest that tyrosine kinase inactivation or tyrosine phosphatase activation may initiate intestinal epithelial cell death.