Late reactivation of sonic hedgehog by Helicobacter pylori results in population of gastric epithelial cells that are resistant to apoptosis: implication for gastric carcinogenesis.

As much as that a disturbance of tissue homeostasis through dysregulated apoptosis is generally associated with carcinogenesis, gastric carcinogenesis after Helicobacter pylori infection could be the accumulated consequence of imbalances between apoptosis and proliferation. Since sonic hedgehog (Shh) has been reported to play versatile roles in various tumorigenesis, we hypothesized that late reactivation of sonic hedgehog by H. pylori infection results in population of gastric epithelial cells that are resistant to apoptosis. The Resistant Clones against H. pylori-induced Apoptosis (RCHA) were established and maintained up to 19th cell passages, during which the serial changes of Shh expression were measured. Apoptosis was measured in N-Shh over-expressed stable cell lines and compared with parent cell line after either infected with H. pylori or treated with cyclopamine. For clinical relevance, the expressions of Shh were compared in tissues from gastric adenoma or adenocarcinoma according to H. pylori infection. Longer passages of RCHA after H. pylori infection, the higher expressions of Shh, suggesting RCHA was associated with the reactivation of Shh. Significant decrement in subG1 phase of cell cycle and attenuated executions of apoptosis after H. pylori infection in cells of Shh overexpression, whereas either Shh siRNA or cyclopamine increased the H. pylori-induced cytotoxicity and significantly abrogated anti-apoptotic actions imposed by Shh. Significantly higher expressions of Shh were seen in H. pylori-associated gastric cancers than H. pylori-not associated gastric cancer. Late reactivation of sonic hedgehog by H. pylori infection results in population of gastric epithelial cells that are resistant to apoptosis and imposes proliferative changes under the background of atrophic gastritis, providing the carcinogenic basis.

Korea red ginseng on Helicobacter pylori-induced halitosis: newer therapeutic strategy and a plausible mechanism.

BACKGROUND: Gas chromatographic documentation of volatile sulfur compounds in Helicobacter pylori cultures and the amelioration of halitosis after eradication suggested a causal link between H. pylori infection and halitosis. AIM: We hypothesized that Korea red ginseng can relieve H. pylori-associated halitosis based on their anti-inflammatory and cytoprotective actions in H. pylori-associated gastritis. METHODS: Eighty-eight functional dyspepsia patients presenting with either subjective halitosis or objective halimeter levels >100 ppb were recruited, on whom tests were repeated after 10 weeks of red ginseng administration. The expressions of cystathionine gamma-lyase (CSE), cystathionine beta-synthetase (CBS), IL-6, IL-8 and IL-1beta mRNA were compared in H. pylori-infected or NaHS-treated gastric epithelial cells according to red ginseng treatment. RESULTS: After 10 weeks of red ginseng administration, 38 patients out of 68 H. pylori-positive cases became 'free of halitosis' accompanied with halimeter levels <50 ppb accordant with the subjective resolution of halitosis. Among the remaining 30 patients, 15 cases administered with both eradication regimen and red ginseng supplement showed either higher eradication rates (93.3%) or were found to be completely free of halitosis in comparison to the other 15 patients who were only administered the eradication regimen. Among 20 H. pylori-negative patients, 13 patients became 'free of halitosis' with 10 weeks of red ginseng treatment alone. Red ginseng extracts significantly decreased H. pylori- or NaHS-induced CSE expressions concomitant with attenuated levels of IL-6, IL-8 and IL-1beta mRNA. CONCLUSION: The strategy consisting of Korea red ginseng supplementation after the successful eradication of H. pylori could be an effective way to fight troublesome halitosis.

Genetic dissection of naturally occurring basal core promoter mutations of hepatitis B virus reveals a silent phenotype in the overlapping X gene.

During chronic hepatitis B virus (HBV) infection, double substitution mutations in the basal core promoter (BCP) region frequently emerge that include A1762T/G1764A and the neighbouring C1766T/T1768A mutations, here termed BCP1 and BCP2, respectively. Due to a compact viral genome organization, BCP1 and BCP2 mutations result in amino acids changes in the overlapping X gene: K130M/V131I and F132Y, respectively. It has been shown that both BCP mutations lead to a modest increase in viral genome replication. However, the question of whether the alteration that occurs in the overlapping X gene might contribute to the increased viral genome replication has not been properly addressed. This study genetically separated the core promoter from the overlapping X gene using 1.3mer overlength HBV constructs and examined the impact of the X gene mutations on viral genome replication in HepG2 cells. Each BCP mutation resulted in modestly enhanced viral genome replication that occurred via augmented viral transcription. Therefore, it was concluded that these BCP mutations do not affect expression of the overlapping X gene or impair its stimulatory effect on viral genome replication.

Stimulation of hepatitis B virus genome replication by HBx is linked to both nuclear and cytoplasmic HBx expression.

HBx, a small regulatory protein of hepatitis B virus, plays an important role in stimulating viral genome replication. HBx was shown to be associated with diverse subcellular locations, such as the nucleus, cytoplasm and mitochondria. Some studies have linked the stimulation of genome replication by HBx to its cytoplasmic function, while other reports have attributed this function to its nuclear component. To clarify this discrepancy, we measured viral genome replication by complementing an HBx-null replicon in two different ways: by (i) co-transfecting with an increasing amount of HBx expression plasmid and (ii) co-transfecting with re-targeted variants of HBx that are confined to either the nucleus or the cytoplasm due to either the nuclear localization signal (NLS) or the nuclear export signal (NES) tags, respectively. Intriguingly, immunostaining analysis indicated that the subcellular localization of HBx is primarily influenced by its abundance; HBx is confined to the nucleus at low levels but is usually detected in the cytoplasm at high levels. Importantly, HBx, whether re-targeted by either the NLS or NES tag, stimulates viral genome replication to a level comparable to that of the wild-type. Furthermore, similar to the wild-type, the stimulation of viral genome replication by the re-targeted HBx occurred at the transcription level. Thus, we concluded that the stimulation of viral genome replication by HBx is linked to both nuclear and cytoplasmic HBx, although the underlying mechanism of stimulation most likely differs.

Volatile sulfur compounds as a predictor for esophagogastroduodenal mucosal injury.

BACKGROUND/AIMS: Halitosis is a symptom that bothers patients more socially than medically and its pathogenic mechanisms are unclear and treatment armamenterium is limited. Clinicians generally ignored active interventions. Since halitosis is closely associated with volatile sulfur compounds (VSCs), we used a Halimeter and gas chromatography to measure VSCs in patients with Helicobacter-pylori (H. pylori)-associated gastric diseases. METHODS: We categorized 72 patients with H. pylori infection into two groups based on their endoscopic findings: a non-erosive mucosal group (NE, n=24) and an erosive mucosal group (E, n=48). Halitosis was objectively assessed by applying either a Halimeter to breath air or gas chromatography to gastric juice. Simultaneously, the expression of VSC-generating enzyme was measured with reverse-transcriptase PCR using mRNA isolated from biopsy tissues. RESULTS: The levels of VSCs in exhaled breaths or aspirated gastric juices differed significantly between the NE and E groups (p<0.00001), suggesting that VSCs might reflect eroded epithelial damage induced by H. pylori infection. The expressions of cystathionine beta-synthase (CBS) and cystathionine gamma-lyase (CSE) were broadly consistent with the degree of mucosal injury. CONCLUSIONS: Erosive changes in esophagogastroduodenal mucosa were strongly correlated with increased VSC levels, suggesting that halitosis might result from H. pylori-associated erosive lesions.