Heat Shock Protein Produced by <i>Helicobacter pylori</i>

Yokota, Kenji; Hirai, Yoshikazu; Haque, Mahmudul; Hayashi, S; Isogai, Hiroshi; Sugiyama, Toshiro; Nagamachi, Eiko; Tsukada, Yutaka; Fujii, Nobuhiro; Oguma, Keiji

doi:10.1111/j.1348-0421.1994.tb01799.x

Cited by 20 publications

(19 citation statements)

References 5 publications

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“…As in the case of the dnaK operon, this study failed to demonstrate inducibility of the promoter by heat shock (34). On the other hand, an increase in the amount of GroEL protein after heat shock has been demonstrated previously (45). Therefore, heat induction of the GroE synthesis was assumed to be regulated posttranscriptionally (34).…”

Section: Vol 182 2000mentioning

confidence: 54%

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Transcriptional Analysis of Major Heat Shock Genes of Helicobacter pylori

Homuth¹,

Domm

Kleiner

et al. 2000

J Bacteriol

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The transcriptional organization and heat inducibility of the major heat shock genes hrcA, dnaK, dnaJ, groEL, and htpG were analyzed on the transcriptional level in Helicobacter pylori strain 69A. The strongly heat-induced dnaK operon was found to be tricistronic, consisting of the genes hrcA, grpE, and dnaK. The dnaJ gene specified one monocistronic mRNA which was also heat inducible. The genes groES and groEL were transcribed as one strongly heat-inducible bicistronic mRNA which exhibited exactly the same induction kinetic as the dnaK operon. Surprisingly, transcription of the monocistronic htpG gene was switched off after heat shock. The data presented are discussed with regard to the different mechanisms regulating expression of heat shock genes in H. pyloriHelicobacter pylori is a gram-negative, spiral-shaped pathogenic bacterium that specifically colonizes the gastric epithelium of primates and is the causative agent of chronic, active type B gastritis in humans (3). The following genetic determinants contribute to the successful colonization of the gastric mucosa: a urease neutralizing the bacterial microenvironment by producing ammonia from the urea present in mucosal sections (9, 10, 14); motility in the gastric mucus and adhesion to the mucosal cell membrane, enabling H. pylori to avoid the extremely low pH of the gastric lumen (11,24,35); and the low-pH-induced synthesis of H. pylori gene products inhibiting acid secretion by mucosal cells (26). As has been demonstrated for all other bacterial species examined so far, H. pylori elicits a heat shock response. Thermoregulation plays an important role in virulence gene expression in pathogenic bacteria including Escherichia coli, Salmonella spp., Shigella spp., and Yersinia spp. Given the importance of the heat shock response in the pathogenesis of other enteric pathogens, this stress response may also play an important role in pathogenesis of H. pylorimediated gastritis.The major heat shock proteins GroES/GroEL and DnaK have been identified in H. pylori. The amount of GroEL increases after heat shock and acid shock (22,45). It has been proposed that GroEL may participate in protection and activity regulation of urease (12,36). An increase in the amount of DnaK after acid shock has also been observed (22). Furthermore, DnaK was reported to be involved in the modulation of glycolipid binding specificity of H. pylori at low pH (21).The aim of this study was to analyze expression of the major H. pylori heat shock genes at the transcriptional level under unstressed conditions and after heat shock. The availability of the published complete H. pylori genome sequence (38) made it possible to generate highly sensitive RNA probes allowing the detection of mRNA specified by the classical heat shock genes hrcA, dnaK, dnaJ, groEL, and htpG.Recently, Spohn and Scarlato demonstrated the negative regulation of the promoters preceding the dnaK and groE operons by the HspR/HAIR (HspR-associated inverted repeat) repressor/operator system in H. pylori G27 (34). Surprising...

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Section: Vol 182 2000mentioning

confidence: 54%

“…The amount of GroEL increases after heat shock and acid shock (22,45). It has been proposed that GroEL may participate in protection and activity regulation of urease (12,36).…”

mentioning

confidence: 99%

Transcriptional Analysis of Major Heat Shock Genes of Helicobacter pylori

Homuth¹,

Domm

Kleiner

et al. 2000

J Bacteriol

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“…The chaperones of the human gastric pathogen H. pylori have been studied in some detail because of their possible involvement in specific virulence mechanisms (9,12,20,25). It has been shown that the groESL, hrcA-grpE-dnaK, and cbpA-hspR-orf operons, encoding the major chaperones of H. pylori, are transcribed by an RNA polymerase containing the vegetative sigma factor 80 and regulated negatively by the transcriptional repressor HspR (17).…”

Section: Discussionmentioning

confidence: 99%

Characterization of the HspR-Mediated Stress Response inHelicobacter pylori

Spohn¹,

Delany²,

Rappuoli³

et al. 2002

J Bacteriol

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The major heat shock genes of Helicobacter pylori are regulated by the HspR repressor. In the present study we characterize the transcriptional response of the three known HspR-dependent promoters P cbp , P gro , and P hrc to different environmental stresses. A temperature shift from 37 to 42°C causes a typical heat shock response at all three promoters characterized by an immediate and strong induction phase of transcription and a subsequent adaptation phase, which is specific for each promoter and whose onset is determined partially by the half-lives of the respective mRNAs. Exposure to high osmolarity induces a similar response on the P gro and P cbp promoters while no such response is detectable at the P hrc promoter. Puromycin treatment induces transcription from all three HspR-dependent promoters, indicating that different environmental stresses are intracellularly sensed by the regulatory machinery through the accumulation of nonnative proteins. The implications of these data for the regulatory network controlling the heat shock response in H. pylori are discussed.The heat shock proteins of the gastric pathogen Helicobacter pylori have been studied in some detail both because of their general role in the protection of the bacteria from the hostile environment represented by the human stomach and because of their involvement in specific pathogenic processes. The H. pylori GroEL (Hsp60) homologue (12, 20) has been proposed to play a role in regulating the activity of the nickel-dependent urease enzyme, which generates ammonia ions from the hydrolysis of urea and therefore protects the bacteria from the low pH of the stomach lumen (4, 6). Its cochaperone GroES (Hsp10) is thought to contribute to this regulation by controlling the availability of nickel ions by means of its intrinsic metal-binding activity (10,20). GroEL as well as another major heat shock protein, DnaK (Hsp70), can furthermore be found in association with the outer membrane, and this surface localization has been suggested to modify the glycolipid binding specificity of H. pylori cells at a low pH (5, 9, 15).Because of their multiple functions in both the general stress response and in specific disease mechanisms, the H. pylori heat shock proteins are expected to be tightly regulated in their expression levels. It was recently demonstrated that transcription of the groESL, hrcA-grpE-dnaK, and cbpA-hspR-orf operons encoding the major chaperones of H. pylori is negatively regulated by HspR (17). HspR is a homologue of the repressor of the dnaK operon of Streptomyces coelicolor (2, 7). By RNA analyses and footprint experiments with purified protein preparations, we have shown that HspR represses transcription by binding to regions of 75 bp on the three chaperone genetranscribing promoters P gro , P hrc , and P cbp . In an attempt to identify the environmental stresses, which induce transcription from these promoters, we subjected H. pylori cultures to both osmotic shock and thermal shock at 45°C. While the P gro and P cbp promoters were found t...

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“…Moreover, in another study, the serum TOS and OSI values decreased after proteins, may be targets of autoimmune responses 110) , and certain data have shown immunologic cross-reactions between bacterial and human HSPs 11,111,112) . For example, H. pylori-derived HSP60 (Hp-HSP60) is an important antigen that is abundantly expressed under various environmental stressors 113) . Hp-HSP60 has been found to appear on antigen-presenting cells in the germinal center in the gastric lymphoid tissues of patients infected with H. pylori 114) , and antibodies cross-reactive to both endogenous HSP60 and Hp-HSP60 have been found in the sera of H. pyloriinfected patients 115,116) .…”

Section: H Pylori and Oxidative Stressmentioning

confidence: 99%

Helicobacter pylori—An Infectious Risk Factor for Atherosclerosis?

Yang

Lü

2014

JAT

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Accumulating evidence implicates Helicobacter pylori (H. pylori) infection in the pathogenesis of certain diseases localized outside the stomach, particularly those characterized by persistent and lowgrade systematic inflammation. Recently, the role of H. pylori infection in the development of atherosclerosis and its clinical complications has received attention. Atherosclerosis is a high-cost disease, and acute events resulting from this condition rank first among morbidity and mortality statistics in most industrialized countries. Atherosclerosis is a multifactorial disorder, and traditional risk factors explain only 50% of its etiology. Therefore, identifying new risk factors for atherosclerosis is necessary. Serological studies indicate that chronic H. pylori infection, especially that with more virulent strains, may predispose patients to the onset of atherosclerosis and related adverse clinical events, and PCR studies have detected H. pylori DNA in atherosclerotic plaques, although this finding remains controversial. If this association were to be confirmed, its importance to public health would be substantial, as the eradication of H. pylori is more straightforward and less costly than the longterm treatment of other risk factors. This review investigates the potential relationship between H. pylori infection and atherosclerosis from both epidemiological and pathogenic perspectives and characterizes the potential mechanisms underlying this correlation.

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Heat Shock Protein Produced by Helicobacter pylori

Cited by 20 publications

References 5 publications

Transcriptional Analysis of Major Heat Shock Genes of Helicobacter pylori

Transcriptional Analysis of Major Heat Shock Genes of Helicobacter pylori

Characterization of the HspR-Mediated Stress Response inHelicobacter pylori

Helicobacter pylori—An Infectious Risk Factor for Atherosclerosis?

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