scholarly journals Acid-Induced Gene Expression in Helicobacter pylori: Study in Genomic Scale by Microarray

2001 ◽  
Vol 69 (3) ◽  
pp. 1679-1686 ◽  
Author(s):  
Sunny Ang ◽  
Cha-Ze Lee ◽  
Konan Peck ◽  
Michelle Sindici ◽  
Udayakumar Matrubutham ◽  
...  
Keyword(s):  
Gene Expression ◽  
Helicobacter Pylori ◽  
Cdna Probe ◽  
Acid Stress ◽  
Growth Conditions ◽  
Open Reading Frames ◽  
Genomic Scale ◽  
Ph Conditions ◽  
H Pylori ◽  
Catalyzed Reporter Deposition

ABSTRACT To understand the RNA expression in response to acid stress ofHelicobacter pylori in genomic scale, a microarray membrane containing 1,534 open reading frames (ORFs) from strain 26695 was used. Total RNAs of H. pylori under growth conditions of pH 7.2 and 5.5 were extracted, reverse transcribed into cDNA, and labeled with biotin. Each microarray membrane was hybridized with cDNA probe from the same strain under two different pH conditions and developed by a catalyzed reporter deposition method. Gene expression of all ORFs was measured by densitometry. Among the 1,534 ORFs, 53 ORFs were highly expressed (≧30% of rRNA control in densitometry ratios). There were 445 ORFs which were stably expressed (<30% of rRNA in densitometry) under both pH conditions without significant variation. A total of 80 ORFs had significantly increased expression levels at low pH, while expressions of 4 ORFs were suppressed under acidic condition. The remaining 952 ORFs were not detectable under either pH condition. These data were highly reproducible and comparable to those obtained by the RNA slot blot method. Our results suggest that microarray can be used in monitoring prokaryotic gene expression in genomic scale.

scholarly journals Acid-Adaptive Genes of Helicobacter pylori

2003 ◽  
Vol 71 (10) ◽  
pp. 5921-5939 ◽  
Author(s):  
Yi Wen ◽  
Elizabeth A. Marcus ◽  
Uday Matrubutham ◽  
Martin A. Gleeson ◽  
David R. Scott ◽  
...  
Keyword(s):  
Gene Expression ◽  
Helicobacter Pylori ◽  
Cell Envelope ◽  
Open Reading Frames ◽  
Ph Optimum ◽  
Transcriptional Regulatory ◽  
Adaptive Mechanisms ◽  
H Pylori ◽  
Reading Frames ◽  
External Ph

ABSTRACT Helicobacter pylori is the only neutralophile that has been able to colonize the human stomach by using a variety of acid-adaptive mechanisms. One of the adaptive mechanisms is increased buffering due to expression of an acid-activated inner membrane urea channel, UreI, and a neutral pH-optimum intrabacterial urease. To delineate other possible adaptive mechanisms, changes in gene expression in response to acid exposure were examined using genomic microarrays of H. pylori exposed to different levels of external pH (7.4, 6.2, 5.5, and 4.5) for 30 min in the absence and presence of 5 mM urea. Gene expression was correlated with intrabacterial pH measured using 2′,7′-bis-(2-carboxyethyl)-5-carboxyfluorescein and compared to that observed with exposure to 42°C for 30 min. Microarrays containing the 1,534 open reading frames of H. pylori strain 26695 were hybridized with cDNAs from control (pH 7.4; labeled with Cy3) and acidic (labeled with Cy5) conditions. The intrabacterial pH was 8.1 at pH 7.4, fell to 5.3 at pH 4.5, and rose to 6.2 with urea. About 200 genes were up-regulated and ∼100 genes were down-regulated at pH 4.5 in the absence of urea, and about half that number changed in the presence of urea. These genes included pH-homeostatic, transcriptional regulatory, motility, cell envelope, and pathogenicity genes. The up-regulation of some pH-homeostatic genes was confirmed by real-time PCR. There was little overlap with the genes induced by temperature stress. These results suggest that H. pylori has evolved multifaceted acid-adaptive mechanisms enabling it to colonize the stomach that may be novel targets for eliminating infection.

scholarly journals Iron and pH Homeostasis Intersect at the Level of Fur Regulation in the Gastric Pathogen Helicobacter pylori

2006 ◽  
Vol 74 (1) ◽  
pp. 602-614 ◽  
Author(s):  
Hanan Gancz ◽  
Stefano Censini ◽  
D. Scott Merrell
Keyword(s):  
Gene Expression ◽  
Helicobacter Pylori ◽  
Dna Microarrays ◽  
Acid Stress ◽  
Fold Increase ◽  
Ph Homeostasis ◽  
Bacterial Gene ◽  
Infectious Dose ◽  
Bacterial Gene Expression ◽  
H Pylori

ABSTRACT Helicobacter pylori persistently colonizes the stomach of the majority of the world's population and is a tremendous medical burden due to its causal role in diverse gastric maladies. Since the stomach is a constantly changing environment, successful colonization of H. pylori within this niche requires regulation of bacterial gene expression to cope with the environmental fluctuations. In H. pylori, the ferric uptake regulator (Fur) has been shown to play an intricate role in adaptation of the bacterium to two conditions known to oscillate within the gastric mucosa: iron limitation and low pH. To extend our knowledge of the process of regulation and adaptation in H. pylori, we show that Fur is required for efficient colonization of the Mongolian gerbil: the mutant strain exhibits a 100-fold increase in the 50% infectious dose, as well as a 100-fold defect in competitive colonization, when coinfected with wild-type bacteria. Furthermore, we used DNA microarrays to identify genes whose expression was altered in a Fur-deficient strain. We show that the Fur regulon of H. pylori consists of approximately 30 genes, most of which have been previously annotated as acid stress associated. Finally, we investigate the role of Fur in acid-responsive modulation of gene expression and show that a large number of genes are aberrantly expressed in the Fur mutant specifically upon acid exposure. This fact likely explains the requirement for this regulator for growth and colonization in the stomach.

scholarly journals Shedding Light on the African Enigma: In Vitro Testing of Homo sapiens-Helicobacter pylori Coevolution

2021 ◽  
Vol 9 (2) ◽  
pp. 240
Author(s):  
Bruno Cavadas ◽  
Marina Leite ◽  
Nicole Pedro ◽  
Ana C. Magalhães ◽  
Joana Melo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Helicobacter Pylori ◽  
Host Response ◽  
Homo Sapiens ◽  
European Ancestry ◽  
Genome Wide ◽  
Expression Host ◽  
H Pylori ◽  
Human Ancestry

The continuous characterization of genome-wide diversity in population and case–cohort samples, allied to the development of new algorithms, are shedding light on host ancestry impact and selection events on various infectious diseases. Especially interesting are the long-standing associations between humans and certain bacteria, such as the case of Helicobacter pylori, which could have been strong drivers of adaptation leading to coevolution. Some evidence on admixed gastric cancer cohorts have been suggested as supporting Homo-Helicobacter coevolution, but reliable experimental data that control both the bacterium and the host ancestries are lacking. Here, we conducted the first in vitro coinfection assays with dual human- and bacterium-matched and -mismatched ancestries, in African and European backgrounds, to evaluate the genome wide gene expression host response to H. pylori. Our results showed that: (1) the host response to H. pylori infection was greatly shaped by the human ancestry, with variability on innate immune system and metabolism; (2) African human ancestry showed signs of coevolution with H. pylori while European ancestry appeared to be maladapted; and (3) mismatched ancestry did not seem to be an important differentiator of gene expression at the initial stages of infection as assayed here.

scholarly journals Genetic Polymorphisms of CXCL8 (−251) Are Associated with the Susceptibility of Helicobacter pylori Infection Increased the Risk of Inflammation and Gastric Cancer in Thai Gastroduodenal Patients

2019 ◽  
Author(s):  
Wongwarut Boonyanugomol ◽  
Kamolchanok Rukseree ◽  
Worrarat Kongkasame ◽  
Prasit Palittapongarnpim ◽  
Seung-Chul Baik ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Cancer Progression ◽  
Chemokine Receptor ◽  
Gene Polymorphisms ◽  
Inflammatory Responses ◽  
Increased Risk ◽  
Cxc Chemokine ◽  
H Pylori

CXC Chemokine Ligand 8 (CXCL8) plays an important role in gastric inflammation and in the progression of gastric cancer induced by Helicobacter pylori (H. pylori) infection. The association of CXCL8, CXC Chemokine Receptor 1 (CXCR1), and CXC Chemokine Receptor 2 (CXCR2) polymorphisms with H. pylori infection and gastric cancer progression needs to be investigated in a population within an enigma area consisting of multiple ethnicities, such as Thailand. To analyze the relative risk of H. pylori infection and gastric cancer among Thai gastroduodenal patients, gene polymorphisms in CXCL8 (promoter region -251) and in CXCR1 and CXCR2 (receptors for CXCL8) were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific-PCR (AS-PCR). We also determined the presence of cytotoxin-associated gene A (cagA) in Thai patients with H. pylori infection. Correlation between the CXCL8 (-251) polymorphism and CXCL8 gene expression was evaluated by quantitative reverse transcriptase-PCR (qRT-PCR). We found a significant association between the T/A and A/A genotypes of CXCL8 (-251) with H. pylori infection. However, no significant correlation was found between the CXCR1 (+2607) and CXCR2 (+1208) gene polymorphisms with H. pylori infection among Thai gastroduodenal subjects. Within the H. pylori-infected group of Thai gastroduodenal patients, no significant differences in cagA were observed. In addition, the A/A genotype of CXCL8 (-251) significantly correlated with the risk of gastric cancer and correlated with higher CXCL8 gene expression levels in Thai gastroduodenal patients. These results suggest that CXCL8 (-251) polymorphisms are associated with H. pylori infection, an increased risk of stronger inflammatory responses, and gastric cancer in Thai gastroduodenal patients.  

scholarly journals Vitamin B6 Is Required for Full Motility and Virulence in Helicobacter pylori

mBio ◽  
2010 ◽  
Vol 1 (3) ◽  
Author(s):  
Alexandra Grubman ◽  
Alexandra Phillips ◽  
Marie Thibonnier ◽  
Maria Kaparakis-Liaskos ◽  
Chad Johnson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Helicobacter Pylori ◽  
Virulence Factors ◽  
Bacterial Pathogens ◽  
Therapeutic Targets ◽  
Vitamin B ◽  
Human Pathogens ◽  
Chronic Colonization ◽  
H Pylori

ABSTRACTDespite recent advances in our understanding of howHelicobacter pyloricauses disease, the factors that allow this pathogen to persist in the stomach have not yet been fully characterized. To identify new virulence factors inH. pylori, we generated low-infectivity variants of a mouse-colonizingH. pyloristrain using the classical technique ofin vitroattenuation. The resulting variants and their highly infectious progenitor bacteria were then analyzed by global gene expression profiling. The gene expression levels of five open reading frames (ORFs) were significantly reduced in low-infectivity variants, with the most significant changes observed for ORFs HP1583 and HP1582. These ORFs were annotated as encoding homologs of theEscherichia colivitamin B6biosynthesis enzymes PdxA and PdxJ. Functional complementation studies withE. coliconfirmedH. pyloriPdxA and PdxJ to bebona fidehomologs of vitamin B6biosynthesis enzymes. Importantly,H. pyloriPdxA was required for optimal growthin vitroand was shown to be essential for chronic colonization in mice. In addition to having a well-known metabolic role, vitamin B6is necessary for the synthesis of glycosylated flagella and for flagellum-based motility inH. pylori. Thus, for the first time, we identify vitamin B6biosynthesis enzymes as novel virulence factors in bacteria. Interestingly,pdxAandpdxJorthologs are present in a number of human pathogens, but not in mammalian cells. We therefore propose that PdxA/J enzymes may represent ideal candidates for therapeutic targets against bacterial pathogens.IMPORTANCEApproximately half of the world’s population is infected withH. pylori, yet howH. pyloribacteria establish chronic infections in human hosts remains elusive. From gene array studies, we identified two genes as representing potentially novel colonization factors forH. pylori. These genes encoded enzymes involved in the synthesis of vitamin B6, an important molecule for many metabolic reactions in living organisms. Little is currently known regarding vitamin B6biosynthesis in human pathogens. We showed that mutantH. pyloribacteria lacking an enzyme involved inde novovitamin B6biosynthesis, PdxA, were unable to synthesize motility appendages (flagella) and were unable to establish chronic colonization in mice. Thus, this work identifies vitamin B6biosynthesis enzymes as novel virulence factors for bacterial pathogens. Interestingly, a number of human pathogens, but not their mammalian hosts, possess these genes, which suggests that Pdx enzymes may represent ideal candidates for new therapeutic targets.

scholarly journals Inhibitory Effect of β-Carotene on Helicobacter pylori-Induced TRAF Expression and Hyper-Proliferation in Gastric Epithelial Cells

Antioxidants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 637 ◽  
Author(s):  
Yongchae Park ◽  
Hanbit Lee ◽  
Joo Weon Lim ◽  
Hyeyoung Kim
Keyword(s):  
Gene Expression ◽  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Nadph Oxidase ◽  
Gastric Epithelial Cells ◽  
Gastric Cancer Cells ◽  
Ags Cells ◽  
H Pylori ◽  
Β Carotene

Helicobacter pylori infection causes the hyper-proliferation of gastric epithelial cells that leads to the development of gastric cancer. Overexpression of tumor necrosis factor receptor associated factor (TRAF) is shown in gastric cancer cells. The dietary antioxidant β-carotene has been shown to counter hyper-proliferation in H. pylori-infected gastric epithelial cells. The present study was carried out to examine the β-carotene mechanism of action. We first showed that H. pylori infection decreases cellular IκBα levels while increasing cell viability, NADPH oxidase activity, reactive oxygen species production, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation, and TRAF1 and TRAF2 gene expression, as well as protein–protein interaction in gastric epithelial AGS cells. We then demonstrated that pretreatment of cells with β-carotene significantly attenuates these effects. Our findings support the proposal that β-carotene has anti-cancer activity by reducing NADPH oxidase-mediated production of ROS, NF-κB activation and NF-κB-regulated TRAF1 and TRAF2 gene expression, and hyper-proliferation in AGS cells. We suggest that the consumption of β-carotene-enriched foods could decrease the incidence of H. pylori-associated gastric disorders.

scholarly journals Involvement of Myeloid Dendritic Cells in the Development of Gastric Secondary Lymphoid Follicles in Helicobacter pylori-Infected Neonatally Thymectomized BALB/c Mice

2003 ◽  
Vol 71 (4) ◽  
pp. 2153-2162 ◽  
Author(s):  
Toshiki Nishi ◽  
Kazuichi Okazaki ◽  
Kimio Kawasaki ◽  
Toshiro Fukui ◽  
Hiroyuki Tamaki ◽  
...  
Keyword(s):  
Gene Expression ◽  
Helicobacter Pylori ◽  
Dendritic Cells ◽  
Epithelial Cells ◽  
Lamina Propria ◽  
Myeloid Dendritic Cells ◽  
Lymphoid Follicles ◽  
Inflammatory Protein ◽  
H Pylori ◽  
Antigen Presenting

ABSTRACT We previously described an animal model of Helicobacter pylori-induced follicular gastritis in neonatally thymectomized (nTx) mice. However, it is still not clear whether antigen-presenting dendritic cells (DCs) in the stomach have a role in the development of secondary follicles in H. pylori-infected nTx mice. We investigated the distribution of DC subsets using this model and examined their roles. To identify lymphoid and myeloid DCs, sections were stained with anti-CD11c (pan-DC marker) in combination with anti-CD8α (lymphoid DC marker) or anti-CD11b (myeloid DC marker) and were examined with a confocal microscope. Expression of macrophage inflammatory protein 3α (MIP-3α), which chemoattracts immature DCs, was analyzed by real-time PCR and immunohistochemistry. Follicular dendritic cells (FDCs) were stained with anti-SKY28 antibodies. In noninfected nTx mice, a few myeloid and lymphoid DCs were observed in the bottom portion of the lamina propria, whereas in H. pylori-infected nTx mice, there was an increased influx of myeloid DCs throughout the lamina propria. FDC staining was also observed in the stomachs of members of the infected group. MIP-3α gene expression was upregulated in the infected nTx group, and the immunohistochemistry analysis revealed MIP-3α-positive epithelial cells. These data suggest that H. pylori infection upregulates MIP-3α gene expression in gastric epithelial cells and induces an influx of myeloid DCs in the lamina propria of the gastric mucosa in nTx mice. Myeloid DCs and FDCs might contribute to the development of gastric secondary lymphoid follicles in H. pylori-infected nTx mice.

scholarly journals The Orphan Response Regulator HP1021 of Helicobacter pylori Regulates Transcription of a Gene Cluster Presumably Involved in Acetone Metabolism

2007 ◽  
Vol 189 (6) ◽  
pp. 2339-2349 ◽  
Author(s):  
Michael Pflock ◽  
Melanie Bathon ◽  
Jennifer Schär ◽  
Stefanie Müller ◽  
Hans Mollenkopf ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Gene Cluster ◽  
Response Regulator ◽  
Transcriptional Profiling ◽  
Acid Resistance ◽  
Housekeeping Genes ◽  
Open Reading Frames ◽  
Considerable Impact ◽  
Two Component Systems ◽  
H Pylori

ABSTRACT Helicobacter pylori is a gastric pathogen for which no nonhuman reservoir is known. In accordance with the tight adaptation to its unique habitat, the human stomach, H. pylori is endowed with a very restricted repertoire of regulatory proteins. Nevertheless, the three complete two-component systems of H. pylori were shown to be involved in the regulation of important virulence traits like motility and acid resistance and in the control of metal homeostasis. HP1021 is an orphan response regulator with an atypical receiver domain whose inactivation has a considerable impact on the growth of H. pylori. Here we report the identification of HP1021-regulated genes by whole-genome transcriptional profiling. We show that the transcription of the essential housekeeping genes nifS and nifU, which are required for the assembly of Fe-S clusters, is activated by HP1021. Furthermore, we demonstrate that the expression of a gene cluster comprising open reading frames hp0690 to hp0693 and hp0695 to hp0697 which is probably involved in acetone metabolism is strongly upregulated by HP1021. Evidence is provided for a direct regulation of the hp0695-to-hp0697 operon by the binding of HP1021 to its promoter region.

scholarly journals Phylogeographic Origin of Helicobacter pylori Determines Host-Adaptive Responses upon Coculture with Gastric Epithelial Cells

2013 ◽  
Vol 81 (7) ◽  
pp. 2468-2477 ◽  
Author(s):  
Alexander Sheh ◽  
Rupesh Chaturvedi ◽  
D. Scott Merrell ◽  
Pelayo Correa ◽  
Keith T. Wilson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Epithelial Cells ◽  
Gastric Disease ◽  
Gastric Epithelial Cells ◽  
Gastric Cancer Risk ◽  
Content Type ◽  
H Pylori ◽  
Induced Apoptosis

ABSTRACTWhileHelicobacter pyloriinfects over 50% of the world's population, the mechanisms involved in the development of gastric disease are not fully understood. Bacterial, host, and environmental factors play a role in disease outcome. To investigate the role of bacterial factors inH. pyloripathogenesis, global gene expression of sixH. pyloriisolates was analyzed during coculture with gastric epithelial cells. Clustering analysis of six Colombian clinical isolates from a region with low gastric cancer risk and a region with high gastric cancer risk segregated strains based on their phylogeographic origin. One hundred forty-six genes had increased expression in European strains, while 350 genes had increased expression in African strains. Differential expression was observed in genes associated with motility, pathogenicity, and other adaptations to the host environment. European strains had greater expression of the virulence factorscagA,vacA, andbabBand were associated with increased gastric histologic lesions in patients. In AGS cells, European strains promoted significantly higher interleukin-8 (IL-8) expression than did African strains. African strains significantly induced apoptosis, whereas only one European strain significantly induced apoptosis. Our data suggest that gene expression profiles of clinical isolates can discriminate strains by phylogeographic origin and that these profiles are associated with changes in expression of the proinflammatory and protumorigenic cytokine IL-8 and levels of apoptosis in host epithelial cells. These findings support the hypothesis that bacterial factors determined by the phylogeographic origin ofH. pyloristrains may promote increased gastric disease.

scholarly journals Delineation of the pH-responsive regulon controlled by the Helicobacter pylori ArsRS two- component system

2021 ◽  
Author(s):  
John T. Loh ◽  
Miranda V. Shum ◽  
Scott D.R. Jossart ◽  
Anne M. Campbell ◽  
Neha Sawhney ◽  
...  
Keyword(s):  
Gene Expression ◽  
Helicobacter Pylori ◽  
Differentially Expressed ◽  
Sensor Kinase ◽  
Ph Responsive ◽  
Two Component System ◽  
Component System ◽  
Wide Range ◽  
Two Component ◽  
H Pylori

Helicobacter pylori encounters a wide range of pH within the human stomach. In a comparison of H. pylori cultured in vitro under neutral or acidic conditions, about 15% of genes are differentially expressed, and corresponding changes are detectable for many of the encoded proteins. The ArsRS two-component system (TCS), comprised of the sensor kinase ArsS and its cognate response regulator ArsR, has an important role in mediating pH-responsive changes in H. pylori gene expression. In this study, we sought to delineate the pH-responsive ArsRS regulon and further define the role of ArsR in pH-responsive gene expression. We compared H. pylori strains containing an intact ArsRS system with an arsS null mutant or strains containing site-specific mutations of a conserved aspartate residue (D52) in ArsR, which is phosphorylated in response to signals relayed by the cognate sensor kinase ArsS. We identified 178 genes that were pH-responsive in strains containing an intact ArsRS system but not in ΔarsS or arsR mutants. These constituents of the pH-responsive ArsRS regulon include genes involved in acid acclimatization (ureAB, amidases), oxidative stress responses (katA, sodB), transcriptional regulation related to iron or nickel homeostasis (fur, nikR), and genes encoding outer membrane proteins [including sabA, alpA, alpB, hopD (labA), and horA]. When comparing H. pylori strains containing an intact ArsRS TCS with arsRS mutants, each cultured at neutral pH, relatively few genes are differentially expressed. Collectively, these data suggest that ArsRS-mediated gene regulation has an important role in H. pylori adaptation to changing pH conditions.

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