1
|
Bohl V, Mogk A. When the going gets tough, the tough get going-Novel bacterial AAA+ disaggregases provide extreme heat resistance. Environ Microbiol 2024; 26:e16677. [PMID: 39039821 DOI: 10.1111/1462-2920.16677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/05/2024] [Indexed: 07/24/2024]
Abstract
Heat stress can lead to protein misfolding and aggregation, potentially causing cell death due to the loss of essential proteins. Bacteria, being particularly exposed to environmental stress, are equipped with disaggregases that rescue these aggregated proteins. The bacterial Hsp70 chaperone DnaK and the ATPase associated with diverse cellular activities protein ClpB form the canonical disaggregase in bacteria. While this combination operates effectively during physiological heat stress, it is ineffective against massive aggregation caused by temperature-based sterilization protocols used in the food industry and clinics. This leaves bacteria unprotected against these thermal processes. However, bacteria that can withstand extreme, man-made stress conditions have emerged. These bacteria possess novel ATPase associated with diverse cellular activities disaggregases, ClpG and ClpL, which are key players in extreme heat resistance. These disaggregases, present in selected Gram-negative or Gram-positive bacteria, respectively, function superiorly by exhibiting increased thermal stability and enhanced threading power compared to DnaK/ClpB. This enables ClpG and ClpL to operate at extreme temperatures and process large and tight protein aggregates, thereby contributing to heat resistance. The genes for ClpG and ClpL are often encoded on mobile genomic islands or conjugative plasmids, allowing for their rapid spread among bacteria via horizontal gene transfer. This threatens the efficiency of sterilization protocols. In this review, we describe the various bacterial disaggregases identified to date, characterizing their commonalities and the specific features that enable these novel disaggregases to provide stress protection against extreme stress conditions.
Collapse
Affiliation(s)
- Valentin Bohl
- Faculty of Biosciences, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| | - Axel Mogk
- Faculty of Biosciences, Center for Molecular Biology of Heidelberg University (ZMBH), Heidelberg, Germany
| |
Collapse
|
2
|
Grünberger F, Schmid G, El Ahmad Z, Fenk M, Vogl K, Reichelt R, Hausner W, Urlaub H, Lenz C, Grohmann D. Uncovering the temporal dynamics and regulatory networks of thermal stress response in a hyperthermophile using transcriptomics and proteomics. mBio 2023; 14:e0217423. [PMID: 37843364 PMCID: PMC10746257 DOI: 10.1128/mbio.02174-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 08/30/2023] [Indexed: 10/17/2023] Open
Abstract
IMPORTANCE Extreme environments provide unique challenges for life, and the study of extremophiles can shed light on the mechanisms of adaptation to such conditions. Pyrococcus furiosus, a hyperthermophilic archaeon, is a model organism for studying thermal stress response mechanisms. In this study, we used an integrated analysis of RNA-sequencing and mass spectrometry data to investigate the transcriptomic and proteomic responses of P. furiosus to heat and cold shock stress and recovery. Our results reveal the rapid and dynamic changes in gene and protein expression patterns associated with these stress responses, as well as the coordinated regulation of different gene sets in response to different stressors. These findings provide valuable insights into the molecular adaptations that facilitate life in extreme environments and advance our understanding of stress response mechanisms in hyperthermophilic archaea.
Collapse
Affiliation(s)
- Felix Grünberger
- Institute of Biochemistry, Genetics and Microbiology, Institute of Microbiology and Archaea Centre, Single-Molecule Biochemistry Lab and Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Georg Schmid
- Institute of Biochemistry, Genetics and Microbiology, Institute of Microbiology and Archaea Centre, Single-Molecule Biochemistry Lab and Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Zubeir El Ahmad
- Institute of Biochemistry, Genetics and Microbiology, Institute of Microbiology and Archaea Centre, Single-Molecule Biochemistry Lab and Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Martin Fenk
- Institute of Biochemistry, Genetics and Microbiology, Institute of Microbiology and Archaea Centre, Single-Molecule Biochemistry Lab and Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Katharina Vogl
- Institute of Biochemistry, Genetics and Microbiology, Institute of Microbiology and Archaea Centre, Single-Molecule Biochemistry Lab and Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Robert Reichelt
- Institute of Biochemistry, Genetics and Microbiology, Institute of Microbiology and Archaea Centre, Single-Molecule Biochemistry Lab and Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Winfried Hausner
- Institute of Biochemistry, Genetics and Microbiology, Institute of Microbiology and Archaea Centre, Single-Molecule Biochemistry Lab and Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| | - Henning Urlaub
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Department of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Christof Lenz
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Department of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Dina Grohmann
- Institute of Biochemistry, Genetics and Microbiology, Institute of Microbiology and Archaea Centre, Single-Molecule Biochemistry Lab and Regensburg Center for Biochemistry, University of Regensburg, Regensburg, Germany
| |
Collapse
|
3
|
Insights into the Orchestration of Gene Transcription Regulators in Helicobacter pylori. Int J Mol Sci 2022; 23:ijms232213688. [PMID: 36430169 PMCID: PMC9696931 DOI: 10.3390/ijms232213688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 10/31/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
Bacterial pathogens employ a general strategy to overcome host defenses by coordinating the virulence gene expression using dedicated regulatory systems that could raise intricate networks. During the last twenty years, many studies of Helicobacter pylori, a human pathogen responsible for various stomach diseases, have mainly focused on elucidating the mechanisms and functions of virulence factors. In parallel, numerous studies have focused on the molecular mechanisms that regulate gene transcription to attempt to understand the physiological changes of the bacterium during infection and adaptation to the environmental conditions it encounters. The number of regulatory proteins deduced from the genome sequence analyses responsible for the correct orchestration of gene transcription appears limited to 14 regulators and three sigma factors. Furthermore, evidence is accumulating for new and complex circuits regulating gene transcription and H. pylori virulence. Here, we focus on the molecular mechanisms used by H. pylori to control gene transcription as a function of the principal environmental changes.
Collapse
|
4
|
Effect of a Stannous Fluoride Dentifrice on Biofilm Composition, Gene Expression and Biomechanical Properties. Microorganisms 2022; 10:microorganisms10091691. [PMID: 36144293 PMCID: PMC9506307 DOI: 10.3390/microorganisms10091691] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/17/2022] [Accepted: 08/18/2022] [Indexed: 11/16/2022] Open
Abstract
An in situ study was conducted to examine the mode of action of a 0.454% stannous fluoride (SnF2)-containing dentifrice in controlling the composition and properties of oral biofilm. Thirteen generally healthy individuals participated in the study. Each participant wore an intra-oral appliance over a 48-h period to measure differences in the resulting biofilm’s architecture, mechanical properties, and bacterial composition after using two different toothpaste products. In addition, metatranscriptomics analysis of supragingival plaque was conducted to identify the gene pathways influenced. The thickness and volume of the microcolonies formed when brushing with the SnF2 dentifrice were dramatically reduced compared to the control 0.76% sodium monofluorophosphate (MFP)-containing toothpaste. Similarly, the biophysical and nanomechanical properties measured by atomic force microscopy (AFM) demonstrated a significant reduction in biofilm adhesive properties. Metatranscriptomic analysis identified pathways associated with biofilm formation, cell adhesion, quorum sensing, and N-glycosylation that are significantly downregulated with SnF2. This study provides a clinically relevant snapshot of how the use of a stabilized, SnF2 toothpaste formulation can change the spatial organization, nanomechanical, and gene expression properties of bacterial communities.
Collapse
|
5
|
Huang Y, Wurihan W, Lu B, Zou Y, Wang Y, Weldon K, Fondell JD, Lai Z, Wu X, Fan H. Robust Heat Shock Response in Chlamydia Lacking a Typical Heat Shock Sigma Factor. Front Microbiol 2022; 12:812448. [PMID: 35046926 PMCID: PMC8762339 DOI: 10.3389/fmicb.2021.812448] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 12/02/2021] [Indexed: 11/13/2022] Open
Abstract
Cells reprogram their transcriptome in response to stress, such as heat shock. In free-living bacteria, the transcriptomic reprogramming is mediated by increased DNA-binding activity of heat shock sigma factors and activation of genes normally repressed by heat-induced transcription factors. In this study, we performed transcriptomic analyses to investigate heat shock response in the obligate intracellular bacterium Chlamydia trachomatis, whose genome encodes only three sigma factors and a single heat-induced transcription factor. Nearly one-third of C. trachomatis genes showed statistically significant (≥1.5-fold) expression changes 30 min after shifting from 37 to 45°C. Notably, chromosomal genes encoding chaperones, energy metabolism enzymes, type III secretion proteins, as well as most plasmid-encoded genes, were differentially upregulated. In contrast, genes with functions in protein synthesis were disproportionately downregulated. These findings suggest that facilitating protein folding, increasing energy production, manipulating host activities, upregulating plasmid-encoded gene expression, and decreasing general protein synthesis helps facilitate C. trachomatis survival under stress. In addition to relieving negative regulation by the heat-inducible transcriptional repressor HrcA, heat shock upregulated the chlamydial primary sigma factor σ66 and an alternative sigma factor σ28. Interestingly, we show for the first time that heat shock downregulates the other alternative sigma factor σ54 in a bacterium. Downregulation of σ54 was accompanied by increased expression of the σ54 RNA polymerase activator AtoC, thus suggesting a unique regulatory mechanism for reestablishing normal expression of select σ54 target genes. Taken together, our findings reveal that C. trachomatis utilizes multiple novel survival strategies to cope with environmental stress and even to replicate. Future strategies that can specifically target and disrupt Chlamydia’s heat shock response will likely be of therapeutic value.
Collapse
Affiliation(s)
- Yehong Huang
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Wurihan Wurihan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Bin Lu
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China.,Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Yi Zou
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Yuxuan Wang
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Korri Weldon
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Joseph D Fondell
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| | - Zhao Lai
- Greehey Children's Cancer Research Institute, University of Texas Health San Antonio, San Antonio, TX, United States.,Department of Molecular Medicine, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Xiang Wu
- Department of Parasitology, Xiangya School of Basic Medicine, Central South University, Changsha, China
| | - Huizhou Fan
- Department of Pharmacology, Robert Wood Johnson Medical School, Rutgers University, Piscataway, NJ, United States
| |
Collapse
|
6
|
Joshi C, Kothari V. Bacterial Stress-response Machinery as a Target for Next-generation Antimicrobials. Infect Disord Drug Targets 2022; 22:e210322202493. [PMID: 35319398 DOI: 10.2174/1871526522666220321153332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 10/30/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Affiliation(s)
- Chinmayi Joshi
- Smt. S.S.Patel Nootan Science and Commerce College, Sankalchand Patel University, Visnagar 384315, India
| | - Vijay Kothari
- Institute of Science, Nirma University, Ahmedabad 382481, India
| |
Collapse
|
7
|
Lou J, Wang J, Yang Y, Yang Q, LI R, Hu M, He Q, Du J, Wang X, Li M, Yang S. Development and characterization of efficient xylose utilization strains of Zymomonas mobilis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:231. [PMID: 34863266 PMCID: PMC8645129 DOI: 10.1186/s13068-021-02082-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/19/2021] [Indexed: 05/15/2023]
Abstract
BACKGROUND Efficient use of glucose and xylose is a key for the economic production of lignocellulosic biofuels and biochemicals, and different recombinant strains have been constructed for xylose utilization including those using Zymomonas mobilis as the host. However, the xylose utilization efficiency still needs to be improved. In this work, the strategy of combining metabolic engineering and adaptive laboratory evolution (ALE) was employed to develop recombinant Z. mobilis strains that can utilize xylose efficiently at high concentrations, and NGS-based genome resequencing and RNA-Seq transcriptomics were performed for strains evolved after serial transfers in different media to understand the impact of xylose and differences among strains with different xylose-utilization capabilities at molecular level. RESULTS Heterologous genes encoding xylose isomerase and xylulokinase were evaluated, which were then introduced into xylose-utilizing strain Z. mobilis 8b to enhance its capacity of xylose utilization. The results demonstrated that the effect of three xylose isomerases on xylose utilization was different, and the increase of copy number of xylose metabolism genes can improve xylose utilization. Among various recombinant strains constructed, the xylose utilization capacity of the recombinant strain 8b-RsXI-xylB was the best, which was further improved through continuous adaption with 38 transfers over 100 days in 50 g/L xylose media. The fermentation performances of the parental strain 8b, the evolved 8b-S38 strain with the best xylose utilization capability, and the intermediate strain 8b-S8 in different media were compared, and the results showed that only 8b-S38 could completely consume xylose at 50 g/L and 100 g/L concentrations. In addition, the xylose consumption rate of 8b-S38 was faster than that of 8b at different xylose concentrations from 50 to 150 g/L, and the ethanol yield increased by 16 ~ 40%, respectively. The results of the mixed-sugar fermentation also demonstrated that 8b-S38 had a higher xylose consumption rate than 8b, and its maximum ethanol productivity was 1.2 ~ 1.4 times higher than that of 8b and 8b-S8. Whole-genome resequencing identified three common genetic changes in 8b-S38 compared with 8b and 8b-S8. RNA-Seq study demonstrated that the expression levels of genes encoding chaperone proteins, ATP-dependent proteases, phage shock proteins, ribosomal proteins, flagellar operons, and transcriptional regulators were significantly increased in xylose media in 8b-S38. The up-regulated expression of these genes may therefore contribute to the efficient xylose utilization of 8b-S38 by maintaining the normal cell metabolism and growth, repairing cellular damages, and rebalancing cellular energy to help cells resist the stressful environment. CONCLUSIONS This study provides gene candidates to improve xylose utilization, and the result of expressing an extra copy of xylose isomerase and xylulokinase improved xylose utilization also provides a direction for efficient xylose-utilization strain development in other microorganisms. In addition, this study demonstrated the necessity to combine metabolic engineering and ALE for industrial strain development. The recombinant strain 8b-S38 can efficiently metabolize xylose for ethanol fermentation at high xylose concentrations as well as in mixed sugars of glucose and xylose, which could be further developed as the microbial biocatalyst for the production of lignocellulosic biofuels and biochemicals.
Collapse
Affiliation(s)
- Jiyun Lou
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Jingwen Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Qing Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Runxia LI
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Mimi Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Qiaoning He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Jun Du
- China Biotech Fermentation Industry Association, Beijing, 100833 China
| | - Xia Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., Ltd., Kaihua County, Zhejiang, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| |
Collapse
|
8
|
Wang M, Zhou T, Liang Y, Li G, Sun Y. Response characteristics of nirS-type denitrifier Paracoccus denitrificans under florfenicol stress. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 219:112355. [PMID: 34049225 DOI: 10.1016/j.ecoenv.2021.112355] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 04/13/2021] [Accepted: 05/16/2021] [Indexed: 06/12/2023]
Abstract
Florfenicol (FF) is widely used in aquaculture and can interfere with denitrification when released into natural ecosystems. The aim of this study was to analyze the response characteristics of nirS-type denitrifier Paracoccus denitrificans under FF stress and further mine antibiotic-responsive factors in aquatic environment. Phenotypic analysis revealed that FF delayed the nitrate removal with a maximum inhibition value of 82.4% at exponential growth phase, leading to nitrite accumulation reached to 21.9-fold and biofilm biomass decreased by ~38.6%, which were due to the lower bacterial population count (P < 0.01). RNA-seq transcriptome analyses indicated that FF treatment decreased the expression of nirS, norB, nosD and nosZ genes that encoded enzymes required for NO2- to N2 conversion from 1.02- to 2.21-fold (P < 0.001). Furthermore, gene associated with the flagellar system FlgL was also down-regulated by 1.03-fold (P < 0.001). Moreover, 10 confirmed sRNAs were significantly induced, which regulated a wide range of metabolic pathways and protein expression. Interestingly, different bacteria contained the same sRNAs means that sRNAs can spread between them. Overall, this study suggests that the denitrification of nirS-type denitrifiers can be hampered widely by FF and the key sRNAs have great potential to be antibiotic-responsive factors.
Collapse
Affiliation(s)
- Mei Wang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China
| | - Tong Zhou
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China
| | - Yi Liang
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China
| | - Ganwu Li
- Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA 50011, USA; State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, China
| | - Yongxue Sun
- Guangdong Provincial Key Laboratory of Veterinary Pharmaceutics Development and Safety Evaluation, South China Agricultural University, 483 Wushan Road, Guangzhou 510642, China.
| |
Collapse
|
9
|
Biofilm Formation as a Complex Result of Virulence and Adaptive Responses of Helicobacter pylori. Pathogens 2020; 9:pathogens9121062. [PMID: 33353223 PMCID: PMC7766044 DOI: 10.3390/pathogens9121062] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022] Open
Abstract
Helicobacter pylori is a bacterium that is capable of colonizing a host for many years, often for a lifetime. The survival in the gastric environment is enabled by the production of numerous virulence factors conditioning adhesion to the mucosa surface, acquisition of nutrients, and neutralization of the immune system activity. It is increasingly recognized, however, that the adaptive mechanisms of H. pylori in the stomach may also be linked to the ability of this pathogen to form biofilms. Initially, biofilms produced by H. pylori were strongly associated by scientists with water distribution systems and considered as a survival mechanism outside the host and a source of fecal-oral infections. In the course of the last 20 years, however, this trend has changed and now the most attention is focused on the biomedical aspect of this structure and its potential contribution to the therapeutic difficulties of H. pylori. Taking into account this fact, the aim of the current review is to discuss the phenomenon of H. pylori biofilm formation and present this mechanism as a resultant of the virulence and adaptive responses of H. pylori, including morphological transformation, membrane vesicles secretion, matrix production, efflux pump activity, and intermicrobial communication. These mechanisms will be considered in the context of transcriptomic and proteomic changes in H. pylori biofilms and their modulating effect on the development of this complex structure.
Collapse
|
10
|
Abstract
The original strategies developed by Helicobacter pylori to persistently colonise its host and to deregulate its cellular functions make this bacterium an outstanding model to study host-pathogen interaction and the mechanisms responsible for bacterial-induced carcinogenesis. During the last year, significant results were obtained on the role of bacterial factors essential for gastric colonisation such as spiral shape maintenance, orientation through chemotaxis and the formation of bacteria clonal population islands inside the gastric glands. Particularities of the H pylori cell surface, a structure important for immune escape, were demonstrated. New insights in the bacterial stress response revealed the importance of DNA methylation-mediated regulation. Further findings were reported on H pylori components that mediate natural transformation and mechanisms of bacterial DNA horizontal transfer which maintain a high level of H pylori genetic variability. Within-host evolution was found to be niche-specific and probably associated with physiological differences between the antral and oxyntic gastric mucosa. In addition, with the progress of CryoEM, high-resolution structures of the major virulence factors, VacA and CagT4SS, were obtained. The use of gastric organoid models fostered research revealing, preferential accumulation of bacteria at the site of injury during infection. Several studies further characterised the role of CagA in the oncogenic properties of H pylori, identifying the activation of novel CagA-dependent pathways, leading to the promotion of genetic instabilities, epithelial-to-mesenchymal transition and finally carcinogenesis. Recent studies also highlight that microRNA-mediated regulation and epigenetic modifications, through DNA methylation, are key events in the H pylori-induced tumorigenesis process.
Collapse
Affiliation(s)
- Milica Denic
- Département de Microbiologie, Institut Pasteur, UMR CNRS 2001, Unité Pathogenèse de Helicobacter, Paris, France.,Sorbonne Paris Cité, Cellule Pasteur, Université Paris Diderot, Paris, France
| | - Eliette Touati
- Département de Microbiologie, Institut Pasteur, UMR CNRS 2001, Unité Pathogenèse de Helicobacter, Paris, France
| | - Hilde De Reuse
- Département de Microbiologie, Institut Pasteur, UMR CNRS 2001, Unité Pathogenèse de Helicobacter, Paris, France
| |
Collapse
|
11
|
Pepe S, Scarlato V, Roncarati D. The Helicobacter pylori HspR-Modulator CbpA Is a Multifunctional Heat-Shock Protein. Microorganisms 2020; 8:microorganisms8020251. [PMID: 32069975 PMCID: PMC7074700 DOI: 10.3390/microorganisms8020251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 01/31/2020] [Accepted: 02/11/2020] [Indexed: 12/24/2022] Open
Abstract
The medically important human pathogen Helicobacter pylori relies on a collection of highly conserved heat-shock and chaperone proteins to preserve the integrity of cellular polypeptides and to control their homeostasis in response to external stress and changing environmental conditions. Among this set of chaperones, the CbpA protein has been shown to play a regulatory role in heat-shock gene regulation by directly interacting with the master stress-responsive repressor HspR. Apart from this regulatory role, little is known so far about CbpA functional activities. Using biochemistry and molecular biology approaches, we have started the in vitro functional characterization of H. pylori CbpA. Specifically, we show that CbpA is a multifunctional protein, being able to bind DNA and to stimulate the ATPase activity of the major chaperone DnaK. In addition, we report a preliminary observation suggesting that CbpA DNA-binding activity can be affected by the direct interaction with the heat-shock master repressor HspR, supporting the hypothesis of a reciprocal crosstalk between these two proteins. Thus, our work defines novel functions for H. pylori CbpA and stimulates further studies aimed at the comprehension of the complex regulatory interplay among chaperones and heat-shock transcriptional regulators.
Collapse
Affiliation(s)
| | - Vincenzo Scarlato
- Correspondence: (V.S.); (D.R.); Tel.: +39-051-2094204 (V.S.); +39-051-2099320 (D.R.)
| | - Davide Roncarati
- Correspondence: (V.S.); (D.R.); Tel.: +39-051-2094204 (V.S.); +39-051-2099320 (D.R.)
| |
Collapse
|