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1.
Int J Mol Sci ; 25(13)2024 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-39000189

RESUMO

Impaired E-cadherin (Cdh1) functions are closely associated with cellular dedifferentiation, infiltrative tumor growth and metastasis, particularly in gastric cancer. The class-I carcinogen Helicobacter pylori (H. pylori) colonizes gastric epithelial cells and induces Cdh1 shedding, which is primarily mediated by the secreted bacterial protease high temperature requirement A (HtrA). In this study, we used human primary epithelial cell lines derived from gastroids and mucosoids from different healthy donors to investigate HtrA-mediated Cdh1 cleavage and the subsequent impact on bacterial pathogenesis in a non-neoplastic context. We found a severe impairment of Cdh1 functions by HtrA-induced ectodomain cleavage in 2D primary cells and mucosoids. Since mucosoids exhibit an intact apico-basal polarity, we investigated bacterial transmigration across the monolayer, which was partially depolarized by HtrA, as indicated by microscopy, the analyses of the transepithelial electrical resistance (TEER) and colony forming unit (cfu) assays. Finally, we investigated CagA injection and observed efficient CagA translocation and tyrosine phosphorylation in 2D primary cells and, to a lesser extent, similar effects in mucosoids. In summary, HtrA is a crucially important factor promoting the multistep pathogenesis of H. pylori in non-transformed primary gastric epithelial cells and organoid-based epithelial models.


Assuntos
Proteínas de Bactérias , Caderinas , Células Epiteliais , Mucosa Gástrica , Helicobacter pylori , Organoides , Humanos , Caderinas/metabolismo , Organoides/metabolismo , Células Epiteliais/metabolismo , Células Epiteliais/microbiologia , Mucosa Gástrica/metabolismo , Mucosa Gástrica/microbiologia , Mucosa Gástrica/patologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Antígenos de Bactérias/metabolismo , Infecções por Helicobacter/metabolismo , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/patologia , Antígenos CD/metabolismo , Estômago/microbiologia , Estômago/patologia , Linhagem Celular , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Neoplasias Gástricas/microbiologia , Serina Proteases
2.
Front Cell Infect Microbiol ; 14: 1419568, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38983115

RESUMO

Background: Helicobacter pylori infection poses a significant health burden worldwide, and its virulence factor CagA plays a pivotal role in its pathogenesis. Methods: In this study, the interaction between H. pylori-infected AGS cells and silver nanoparticles (AgNPs) was investigated, with a focus on the modulation of CagA-mediated responses, investigated by western blotting. Both, the dose-dependent efficacy against H. pylori (growth curves, CFU assay) and the impact of the nanoparticles on AGS cells (MTT assay) were elucidated. Results: AGS cells infected with H. pylori displayed dramatic morphological changes, characterized by elongation and a migratory phenotype, attributed to CagA activity. Preincubation of H. pylori with AgNPs affected these morphological changes in a concentration-dependent manner, suggesting a correlation between AgNPs concentration and CagA function. Conclusion: Our study highlights the nuanced interplay between host-pathogen interactions and the therapeutic potential of AgNPs in combating H. pylori infection and offers valuable insights into the multifaceted dynamics of CagA mediated responses.


Assuntos
Antígenos de Bactérias , Proteínas de Bactérias , Infecções por Helicobacter , Helicobacter pylori , Nanopartículas Metálicas , Transdução de Sinais , Prata , Helicobacter pylori/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , Antígenos de Bactérias/metabolismo , Prata/farmacologia , Prata/metabolismo , Humanos , Infecções por Helicobacter/microbiologia , Infecções por Helicobacter/tratamento farmacológico , Transdução de Sinais/efeitos dos fármacos , Interações Hospedeiro-Patógeno , Células Epiteliais/microbiologia , Fatores de Virulência/metabolismo , Linhagem Celular , Antibacterianos/farmacologia , Linhagem Celular Tumoral
3.
Front Immunol ; 14: 1290833, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38053995

RESUMO

Helicobacter pylori is a widespread Gram-negative pathogen involved in a variety of gastrointestinal diseases, including gastritis, ulceration, mucosa-associated lymphoid tissue (MALT) lymphoma and gastric cancer. Immune responses aimed at eradication of H. pylori often prove futile, and paradoxically play a crucial role in the degeneration of epithelial integrity and disease progression. We have previously shown that H. pylori infection of primary human monocytes increases their potential to respond to subsequent bacterial stimuli - a process that may be involved in the generation of exaggerated, yet ineffective immune responses directed against the pathogen. In this study, we show that H. pylori-induced monocyte priming is not a common feature of Gram-negative bacteria, as Acinetobacter lwoffii induces tolerance to subsequent Escherichia coli lipopolysaccharide (LPS) challenge. Although the increased reactivity of H. pylori-infected monocytes seems to be specific to H. pylori, it appears to be independent of its virulence factors Cag pathogenicity island (CagPAI), cytotoxin associated gene A (CagA), vacuolating toxin A (VacA) and γ-glutamyl transferase (γ-GT). Utilizing whole-cell proteomics complemented with biochemical signaling studies, we show that H. pylori infection of monocytes induces a unique proteomic signature compared to other pro-inflammatory priming stimuli, namely LPS and the pathobiont A. lwoffii. Contrary to these tolerance-inducing stimuli, H. pylori priming leads to accumulation of NF-кB proteins, including p65/RelA, and thus to the acquisition of a monocyte phenotype more responsive to subsequent LPS challenge. The plasticity of pro-inflammatory responses based on abundance and availability of intracellular signaling molecules may be a heretofore underappreciated form of regulating innate immune memory as well as a novel facet of the pathobiology induced by H. pylori.


Assuntos
Helicobacter pylori , NF-kappa B , Humanos , NF-kappa B/metabolismo , Proteínas de Bactérias , Imunidade Treinada , Lipopolissacarídeos/metabolismo , Proteômica
4.
Protein J ; 42(4): 343-354, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37093417

RESUMO

In many bacteria, the High Temperature requirement A (HtrA) protein functions as a chaperone and protease. HtrA is an important factor in stress tolerance and plays a significant role in the virulence of several pathogenic bacteria. Camostat, gabexate and nafamostat mesylates are serine protease inhibitors and have recently shown a great impact in the inhibition studies of SARS-CoV2. In this study, the inhibition of Listeria monocytogenes HtrA (LmHtrA) protease activity was analysed using these three inhibitors. The cleavage assay, using human fibrinogen and casein as substrates, revealed that the three inhibitors effectively inhibit the protease activity of LmHtrA. The agar plate assay and spectrophotometric analysis concluded that the inhibition of nafamostat (IC50 value of 6.6 ± 0.4 µM) is more effective compared to the other two inhibitors. Previous studies revealed that at the active site of the protease, these inhibitors are hydrolysed and one of the hydrolysates is covalently bound to the active site serine. To understand the mode of binding of these inhibitors at the active site of LmHtrA, docking of the inhibitors followed by molecular dynamics simulations were carried out. Analysis of the LmHtrA-inhibitor complex structures revealed that the covalently bound inhibitor is unable to occupy the S1 pocket of the LmHtrA which is in contrast to the previously determined camostat and nafamostat complex structures. This observation provides the first glimpse of the substrate specificity of LmHtrA which is not known. The obtained results also suggest that the development of novel inhibitors of LmHtrA and its homologs with active site architecture similar to LmHtrA can be pursued with suitable modification of these inhibitors. To date, only a very few studies have been carried out on identifying the inhibitors of HtrA proteolytic activity.


Assuntos
COVID-19 , Gabexato , Listeria monocytogenes , Humanos , Gabexato/farmacologia , Peptídeo Hidrolases , RNA Viral , SARS-CoV-2 , Mesilatos , Inibidores de Proteases/farmacologia
5.
Curr Top Microbiol Immunol ; 444: 259-277, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38231222

RESUMO

Helicobacter pylori (H. pylori) proteases have become a major focus of research in recent years, because they not only have an important function in bacterial physiology, but also directly alter host cell functions. In this review, we summarize recent findings on extracellular H. pylori proteases that target host-derived substrates to facilitate bacterial pathogenesis. In particular, the secreted H. pylori collagenase (Hp0169), the metalloprotease Hp1012, or the serine protease High temperature requirement A (HtrA) are of great interest. Specifically, various host cell-derived substrates were identified for HtrA that directly interfere with the gastric epithelial barrier allowing full pathogenesis. In light of increasing antibiotic resistance, the development of inhibitory compounds for extracellular proteases as potential targets is an innovative field that offers alternatives to existing therapies.


Assuntos
Infecções por Helicobacter , Helicobacter pylori , Gastropatias , Humanos , Peptídeo Hidrolases , Helicobacter pylori/genética , Infecções por Helicobacter/tratamento farmacológico , Endopeptidases
6.
J Med Chem ; 65(19): 12933-12955, 2022 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-36154055

RESUMO

In view of the worldwide antimicrobial resistance (AMR) threat, new bacterial targets and anti-infective agents are needed. Since important roles in bacterial pathogenesis have been demonstrated for the collagenase H and G (ColH and ColG) from Clostridium histolyticum, collagenase Q1 and A (ColQ1 and ColA) from Bacillus cereus represent attractive antivirulence targets. Furthermore, repurposing FDA-approved drugs may assist to tackle the AMR crisis and was addressed in this work. Here, we report on the discovery of two potent and chemically stable bacterial collagenase inhibitors: synthesized and FDA-approved diphosphonates and hydroxamates. Both classes showed high in vitro activity against the clostridial and bacillary collagenases. The potent diphosphonates reduced B. cereus-mediated detachment and death of cells and Galleria mellonella larvae. The hydroxamates were also tested in a similar manner; they did not have an effect in infection models. This might be due to their fast binding kinetics to bacterial collagenases.


Assuntos
Inibidores de Metaloproteinases de Matriz , Colagenase Microbiana , Clostridium histolyticum , Colagenases/metabolismo , Difosfonatos
7.
Int J Mol Sci ; 23(5)2022 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-35269560

RESUMO

Gastric cancer is a leading cause of cancer-related death, and a large proportion of cases are inseparably linked to infections with the bacterial pathogen and type I carcinogen Helicobacter pylori. The development of gastric cancer follows a cascade of transformative tissue events in an inflammatory environment. Proteases of host origin as well as H. pylori-derived proteases contribute to disease progression at every stage, from chronic gastritis to gastric cancer. In the present article, we discuss the importance of (metallo-)proteases in colonization, epithelial inflammation, and barrier disruption in tissue transformation, deregulation of cell proliferation and cell death, as well as tumor metastasis and neoangiogenesis. Proteases of the matrix metalloproteinase (MMP) and a disintegrin and metalloproteinase domain-containing protein (ADAM) families, caspases, calpain, and the H. pylori proteases HtrA, Hp1012, and Hp0169 cleave substrates including extracellular matrix molecules, chemokines, and cytokines, as well as their cognate receptors, and thus shape the pathogenic microenvironment. This review aims to summarize the current understanding of how proteases contribute to disease progression in the gastric compartment.


Assuntos
Infecções por Helicobacter/imunologia , Helicobacter pylori/patogenicidade , Peptídeo Hidrolases/metabolismo , Neoplasias Gástricas/patologia , Proteínas de Bactérias/metabolismo , Progressão da Doença , Regulação da Expressão Gênica , Infecções por Helicobacter/complicações , Helicobacter pylori/imunologia , Humanos , Metaloproteases/metabolismo , Proteólise , Serina Proteases/metabolismo , Neoplasias Gástricas/microbiologia
8.
Biomolecules ; 12(3)2022 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-35327548

RESUMO

Helicobacter pylori (H. pylori) expresses the serine protease and chaperone High temperature requirement A (HtrA) that is involved in periplasmic unfolded protein stress response. Additionally, H. pylori-secreted HtrA directly cleaves the human cell adhesion molecule E-cadherin leading to a local disruption of intercellular adhesions during pathogenesis. HtrA-mediated E-cadherin cleavage has been observed in response to a broad range of pathogens, implying that it is a prevalent mechanism in humans. However, less is known whether E-cadherin orthologues serve as substrates for bacterial HtrA. Here, we compared HtrA-mediated cleavage of human E-cadherin with murine, canine, and simian E-cadherin in vitro and during bacterial infection. We found that HtrA targeted mouse and dog E-cadherin equally well, whereas macaque E-cadherin was less fragmented in vitro. We stably re-expressed orthologous E-cadherin (Cdh1) in a CRISPR/Cas9-mediated cdh1 knockout cell line to investigate E-cadherin shedding upon infection using H. pylori wildtype, an isogenic htrA deletion mutant, or complemented mutants as bacterial paradigms. In Western blot analyses and super-resolution microscopy, we demonstrated that H. pylori efficiently cleaved E-cadherin orthologues in an HtrA-dependent manner. These data extend previous knowledge to HtrA-mediated E-cadherin release in mammals, which may shed new light on bacterial infections in non-human organisms.


Assuntos
Helicobacter pylori , Serina Proteases , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Caderinas/genética , Caderinas/metabolismo , Cães , Helicobacter pylori/metabolismo , Mamíferos/metabolismo , Camundongos , Serina Endopeptidases/metabolismo , Serina Proteases/genética , Serina Proteases/metabolismo , Temperatura
9.
Adv Ther (Weinh) ; 5(3): 2100222, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35310821

RESUMO

Despite the progress in surgical techniques and antibiotic prophylaxis, opportunistic wound infections with Bacillus cereus remain a public health problem. Secreted toxins are one of the main factors contributing to B. cereus pathogenicity. A promising strategy to treat such infections is to target these toxins and not the bacteria. Although the exoenzymes produced by B. cereus are thoroughly investigated, little is known about the role of B. cereus collagenases in wound infections. In this report, the collagenolytic activity of secreted collagenases (Col) is characterized in the B. cereus culture supernatant (csn) and its isolated recombinantly produced ColQ1 is characterized. The data reveals that ColQ1 causes damage on dermal collagen (COL). This results in gaps in the tissue, which might facilitate the spread of bacteria. The importance of B. cereus collagenases is also demonstrated in disease promotion using two inhibitors. Compound 2 shows high efficacy in peptidolytic, gelatinolytic, and COL degradation assays. It also preserves the fibrillar COLs in skin tissue challenged with ColQ1, as well as the viability of skin cells treated with B. cereus csn. A Galleria mellonella model highlights the significance of collagenase inhibition in vivo.

10.
Cell Commun Signal ; 19(1): 108, 2021 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-34742300

RESUMO

BACKGROUND: High temperature requirement A (HtrA) is an active serine protease secreted by the group-I carcinogen Helicobacter pylori (H. pylori). The human cell adhesion protein and tumor suppressor E-cadherin (hCdh1) expressed on the surface of gastric epithelial cells was identified as the first HtrA substrate. HtrA-mediated hCdh1 cleavage and subsequent disruption of intercellular adhesions are considered as important steps in H. pylori pathogenesis. In this study, we performed a proteomic profiling of H. pylori HtrA (HpHtrA) to decipher the complex mechanism of H. pylori interference with the epithelial barrier integrity. RESULTS: Using a proteomic approach we identified human desmoglein-2 (hDsg2), neuropilin-1, ephrin-B2, and semaphorin-4D as novel extracellular HpHtrA substrates and confirmed the well characterized target hCdh1. HpHtrA-mediated hDsg2 cleavage was further analyzed by in vitro cleavage assays using recombinant proteins. In infection experiments, we demonstrated hDsg2 shedding from H. pylori-colonized MKN28 and NCI-N87 cells independently of pathogen-induced matrix-metalloproteases or ADAM10 and ADAM17. CONCLUSIONS: Characterizing the substrate specificity of HpHtrA revealed efficient hDsg2 cleavage underlining the importance of HpHtrA in opening intercellular junctions. Video Abstract.


Assuntos
Proteínas de Bactérias/genética , Desmogleína 2/genética , Infecções por Helicobacter/genética , Helicobacter pylori/genética , Interações Hospedeiro-Patógeno/genética , Serina Proteases/genética , Proteína ADAM10/genética , Proteína ADAM17/genética , Efrina-B2/genética , Células Epiteliais/microbiologia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/patogenicidade , Humanos , Neuropilina-1/genética , Proteômica/métodos , Semaforinas/genética
11.
FEMS Microbiol Lett ; 368(20)2021 11 27.
Artigo em Inglês | MEDLINE | ID: mdl-34755852

RESUMO

High Temperature Requirement A (HtrA) was identified as a secreted virulence factor in many pathogenic bacteria, including Listeria monocytogenes. Recently, it was discovered that Helicobacter pylori and Campylobacter jejuni HtrAs can directly cleave the human cell-adhesion molecule E-cadherin, which facilitates bacterial transmigration. HtrAs also interact with extracellular matrix (ECM) molecules. However, only a limited number of studies have been carried out in this regard. In the present study, the protease and ECM binding properties of L. monocytogenes HtrA (LmHtrA) were studied using native rLmHtrA, catalytically inactive rLmHtrA(S343A) and rLmHtrA lacking the PDZ domain (∆PDZ) to gain more insights into HtrA-ECM molecule interaction. The results show that (1) native rLmHtrA cleaves fibrinogen, fibronectin, plasminogen and casein in a time and temperature dependent manner, (2) interaction of rLmHtrA with various host proteins was found in the micromolar to nanomolar range, (3) in the absence of PDZ domain, rLmHtrA exhibits no drastic change in binding affinity toward the host molecules when compared with native rLmHtrA and (4) the PDZ domain plays an important role in the substrate cleavage as rLmHtrA1-394∆PDZ cleaves the substrates only under certain conditions. The proteolysis of various ECM molecules by rLmHtrA possibly highlights the role of HtrA in L. monocytogenes pathogenesis involving ECM degradation.


Assuntos
Proteínas de Bactérias/metabolismo , Matriz Extracelular , Listeria monocytogenes , Proteínas de Membrana/metabolismo , Serina Endopeptidases/metabolismo , Proteínas de Bactérias/genética , Matriz Extracelular/metabolismo , Humanos , Listeria monocytogenes/enzimologia , Listeria monocytogenes/genética , Listeria monocytogenes/metabolismo , Proteínas de Membrana/genética , Ligação Proteica , Domínios Proteicos/genética , Serina Endopeptidases/genética
12.
Toxins (Basel) ; 13(9)2021 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-34564597

RESUMO

BACKGROUND: Helicobacter pylori (Hp) colonizes the human stomach and can induce gastric cancer and mucosa-associated lymphoid tissue (MALT) lymphoma. Clinical observations suggest a role for the Hp virulence factor cytotoxin-associated gene A (CagA) in pathogenesis. The pathogenic activity of CagA is partly regulated by tyrosine phosphorylation of C-terminal Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs in host cells. However, CagA differs considerably in EPIYA motifs, whose functions have been well characterized in epithelial cells. Since CagA is fragmented in immune cells, different CagA variants may exhibit undetected functions in B cells. METHODS: B cells were infected with Hp isolates and isogenic mutants expressing different CagA EPIYA variants. CagA translocation and tyrosine phosphorylation were investigated by Western blotting. Apoptosis was analyzed by flow cytometry and metabolic activity was detected by an MTT assay. RESULTS: Isogenic CagA EPIYA variants are equally well translocated into B cells, followed by tyrosine phosphorylation and cleavage. B cell apoptosis was induced in a CagA-independent manner. However, variants containing at least one EPIYA-C motif affected metabolic activity independently of phosphorylation or multiplication of EPIYA-C motifs. CONCLUSIONS: The diverse structure of CagA regulates B cell physiology, whereas B cell survival is independent of CagA.


Assuntos
Infecções por Helicobacter/metabolismo , Infecções por Helicobacter/fisiopatologia , Helicobacter pylori/genética , Helicobacter pylori/patogenicidade , Linfoma de Zona Marginal Tipo Células B/metabolismo , Linfoma de Zona Marginal Tipo Células B/fisiopatologia , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/fisiopatologia , Citotoxinas/genética , Citotoxinas/metabolismo , Regulação Bacteriana da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Variação Genética , Genótipo , Interações Hospedeiro-Patógeno/genética , Humanos
13.
Cell Commun Signal ; 18(1): 160, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-33023610

RESUMO

BACKGROUND: Helicobacter pylori (H. pylori) is a gram-negative bacterium that chronically infects approximately 50% of the world's human population. While in most cases the infection remains asymptomatic, 10% of infected individuals develop gastric pathologies and 1-3% progress to gastric cancer. Although H. pylori induces severe inflammatory responses, the host's immune system fails to clear the pathogen and H. pylori can persist in the human stomach for decades. As suppressor of cytokine signaling (SOCS) proteins are important feedback regulators limiting inflammatory responses, we hypothesized that H. pylori could modulate the host's immune responses by inducing SOCS expression. METHODS: The phenotype of human monocyte-derived DCs (moDCs) infected with H. pylori was analyzed by flow cytometry and multiplex technology. SOCS expression levels were monitored by qPCR and signaling studies were conducted by means of Western blot. For functional studies, RNA interference-based silencing of SOCS1-3 and co-cultures with CD4+ T cells were performed. RESULTS: We show that H. pylori positive gastritis patients express significantly higher SOCS3, but not SOCS1 and SOCS2, levels compared to H. pylori negative patients. Moreover, infection of human moDCs with H. pylori rapidly induces SOCS3 expression, which requires the type IV secretion system (T4SS), release of TNFα, and signaling via the MAP kinase p38, but appears to be independent of TLR2, TLR4, MEK1/2 and STAT proteins. Silencing of SOCS3 expression in moDCs prior to H. pylori infection resulted in increased release of both pro- and anti-inflammatory cytokines, upregulation of PD-L1, and decreased T-cell proliferation. CONCLUSIONS: This study shows that H. pylori induces SOCS3 via an autocrine loop involving the T4SS and TNFα and p38 signaling. Moreover, we demonstrate that high levels of SOCS3 in DCs dampen PD-L1 expression on DCs, which in turn drives T-cell proliferation. Video Abstract.


Assuntos
Sistemas de Secreção Bacterianos , Células Dendríticas/metabolismo , Células Dendríticas/microbiologia , Helicobacter pylori/fisiologia , Proteína 3 Supressora da Sinalização de Citocinas/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Antígenos de Bactérias/metabolismo , Antígeno B7-H1/metabolismo , Proteínas de Bactérias/metabolismo , Proliferação de Células , Quimiocinas/metabolismo , Retroalimentação Fisiológica , Infecções por Helicobacter/metabolismo , Humanos , Janus Quinases/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Monócitos/metabolismo , Mutação/genética , Fosforilação , Transdução de Sinais , Receptores Toll-Like/metabolismo
14.
Microorganisms ; 8(9)2020 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-32878302

RESUMO

Persistent infections with the human pathogen Helicobacter pylori (H. pylori) have been closely associated with the induction and progression of a wide range of gastric disorders, including acute and chronic gastritis, ulceration in the stomach and duodenum, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric adenocarcinoma. The pathogenesis of H. pylori is determined by a complicated network of manifold mechanisms of pathogen-host interactions, which involves a coordinated interplay of H. pylori pathogenicity and virulence factors with host cells. While these molecular and cellular mechanisms have been intensively investigated to date, the knowledge about outer membrane vesicles (OMVs) derived from H. pylori and their implication in bacterial pathogenesis is not well developed. In this review, we summarize the current knowledge on H. pylori-derived OMVs.

15.
Pathog Dis ; 78(7)2020 10 08.
Artigo em Inglês | MEDLINE | ID: mdl-32866262

RESUMO

Persistent infections with the bacterial group-I carcinogen Helicobacter pylori (H. pylori) have been associated with a broad range of gastric disorders, including gastritis, ulceration, gastric cancer or mucosa-associated lymphoid tissue (MALT) lymphoma. Pathogenesis of H. pylori requires a balance between immune tolerance and defense. Although H. pylori induces inflammatory responses, the immune system cannot eliminate the pathogen. The detailed molecular mechanisms of how H. pylori interferes with cells of the immune system, in particular infiltrated B cells, are not well investigated. Previously, it was shown that the bacterial effector and oncoprotein cytotoxin-associated gene A (CagA) is delivered into B cells followed by its tyrosine-phosphorylation. To investigate the functional consequences in B cells colonized by CagA-positive H. pylori, we analyzed the global transcriptome of H. pylori-infected Mec-1 cells by RNA sequencing. We found 889 differentially expressed genes (DEGs) and validated JUN, FOSL2, HSPA1B, SRC, CXCR3, TLR-4, TNF-α, CXCL8, CCL2, CCL4, MHC class I and MHC class II molecules by qPCR, western blot, flow cytometry and ELISA assays. The H. pylori-specific mRNA expression signature reveals a downregulation of inflammation- and migration-associated genes, whereas central signal transduction regulators of cell survival and death are upregulated.


Assuntos
Linfócitos B/imunologia , Linfócitos B/metabolismo , Infecções por Helicobacter/genética , Infecções por Helicobacter/microbiologia , Helicobacter pylori/fisiologia , Interações Hospedeiro-Patógeno/genética , Transcriptoma , Biologia Computacional/métodos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Infecções por Helicobacter/complicações , Infecções por Helicobacter/imunologia , Interações Hospedeiro-Patógeno/imunologia , Humanos , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Linfoma de Zona Marginal Tipo Células B/etiologia , Reprodutibilidade dos Testes , Neoplasias Gástricas/etiologia
16.
Biochemistry ; 59(39): 3772-3781, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-32936629

RESUMO

Naturally occurring membranolytic antimicrobial peptides (AMPs) are rarely cell-type selective and highly potent at the same time. Template-based peptide design can be used to generate AMPs with improved properties de novo. Following this approach, 18 linear peptides were obtained by computationally morphing the natural AMP Aurein 2.2d2 GLFDIVKKVVGALG into the synthetic model AMP KLLKLLKKLLKLLK. Eleven of the 18 chimeric designs inhibited the growth of Staphylococcus aureus, and six peptides were tested and found to be active against one resistant pathogenic strain or more. One of the peptides was broadly active against bacterial and fungal pathogens without exhibiting toxicity to certain human cell lines. Solution nuclear magnetic resonance and molecular dynamics simulation suggested an oblique-oriented membrane insertion mechanism of this helical de novo peptide. Temperature-resolved circular dichroism spectroscopy pointed to conformational flexibility as an essential feature of cell-type selective AMPs.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Sequência de Aminoácidos , Desenho de Fármacos , Células HEK293 , Humanos , Simulação de Dinâmica Molecular , Conformação Proteica em alfa-Hélice , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/crescimento & desenvolvimento
17.
Sci Rep ; 10(1): 10563, 2020 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-32601479

RESUMO

Helicobacter pylori (H. pylori) secretes the chaperone and serine protease high temperature requirement A (HtrA) that cleaves gastric epithelial cell surface proteins to disrupt the epithelial integrity and barrier function. First inhibitory lead structures have demonstrated the essential role of HtrA in H. pylori physiology and pathogenesis. Comprehensive drug discovery techniques allowing high-throughput screening are now required to develop effective compounds. Here, we designed a novel fluorescence resonance energy transfer (FRET) peptide derived from a gel-based label-free proteomic approach (direct in-gel profiling of protease specificity) as a valuable substrate for H. pylori HtrA. Since serine proteases are often sensitive to metal ions, we investigated the influence of different divalent ions on the activity of HtrA. We identified Zn++ and Cu++ ions as inhibitors of H. pylori HtrA activity, as monitored by in vitro cleavage experiments using casein or E-cadherin as substrates and in the FRET peptide assay. Putative binding sites for Zn++ and Cu++ were then analyzed in thermal shift and microscale thermophoresis assays. The findings of this study will contribute to the development of novel metal ion-dependent protease inhibitors, which might help to fight bacterial infections.


Assuntos
Proteínas de Bactérias/antagonistas & inibidores , Avaliação Pré-Clínica de Medicamentos/métodos , Transferência Ressonante de Energia de Fluorescência/métodos , Proteínas de Bactérias/metabolismo , Caderinas/metabolismo , Cobre/metabolismo , Infecções por Helicobacter/tratamento farmacológico , Infecções por Helicobacter/metabolismo , Helicobacter pylori/metabolismo , Chaperonas Moleculares/metabolismo , Peptídeos/metabolismo , Proteômica/métodos , Serina Endopeptidases/metabolismo , Serina Proteases/metabolismo , Zinco/metabolismo
18.
Gut Microbes ; 12(1): 1770017, 2020 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-32584649

RESUMO

Mechanisms of host-pathogen interactions resulting in immunopathological responses upon human Campylobacter jejuni infection are not completely understood, but the recent availability of murine infection models mimicking key features of campylobacteriosis helps solving this dilemma. During a screen for proteases expressed by C. jejuni, we identified a peptidase of the M24 family as a potential novel virulence factor, which was named PepP. The gene is strongly conserved in various Campylobacter species. A constructed deletion mutant ΔpepP of C. jejuni strain 81-176 grew as efficiently compared to isogenic wild-type (WT) or pepP complemented bacteria. To shed light on the potential role of this protease in mediating immunopathological responses in the mammalian host, we perorally challenged microbiota-depleted IL-10-/- mice with these strains. All strains stably colonized the murine gastrointestinal tract with comparably high loads. Remarkably, pepP deficiency was associated with less severe induced malaise, with less distinct apoptotic and innate immune cell responses, but also with more pronounced proliferative/regenerative epithelial cell responses in the large intestine at d6post-infection. Furthermore, pro-inflammatory mediators were lower in the colon, ileum, and mesenteric lymph nodes of mice that had been challenged with the ΔpepP mutant compared to the WT or pepP complemented strains. This also held true for extra-intestinal organs including liver, kidneys, and lungs, and, strikingly, to systemic compartments. Taken together, protease PepP is a novel virulence determinant involved in mediating campylobacteriosis. The finding that apoptosis in the colon is significantly diminished in mice infected with the pepP mutant highlights the epithelial layer as the first and main target of PepP in the intestine.


Assuntos
Infecções por Campylobacter/microbiologia , Campylobacter jejuni , Microbioma Gastrointestinal/fisiologia , Serina Endopeptidases/genética , Animais , Apoptose/fisiologia , Campylobacter jejuni/genética , Campylobacter jejuni/imunologia , Campylobacter jejuni/patogenicidade , Feminino , Doenças Transmitidas por Alimentos/microbiologia , Trato Gastrointestinal/microbiologia , Trato Gastrointestinal/patologia , Interleucina-10/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Serina Endopeptidases/metabolismo , Fatores de Virulência/genética
19.
Int J Mol Sci ; 21(11)2020 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-32486097

RESUMO

Helicobacter pylori (H. pylori) is a stomach pathogen that persistently colonizes the gastric mucosa, often leading to chronic inflammation and gastric pathologies. Although infection with H. pylori is the primary risk factor for gastric cancer, the underlying mechanisms of pathogen persistence and consequential chronic inflammation are still not well understood. Conventional dendritic cells (cDCs), which are among the first immune cells to encounter H. pylori in the gastric lining, and the cytokines and chemokines they secrete, contribute to both acute and chronic inflammation. Therefore, this study aimed to unravel the contributions of specific signaling pathways within human CD1c+ cDCs (cDC2s) to the composition of secreted cytokines and chemokines in H. pylori infection. Here, we show that the type IV secretion system (T4SS) plays only a minor role in H. pylori-induced activation of cDC2s. In contrast, Toll-like receptor 4 (TLR4) signaling drives the secretion of inflammatory mediators, including IL-12 and IL-18, while signaling via TLR10 attenuates the release of IL-1ß and other inflammatory cytokines upon H. pylori infection. The TLR2 pathway significantly blocks the release of CXCL1 and CXCL8, while it promotes the secretion of TNFα and GM-CSF. Taken together, these results highlight how specific TLR-signaling pathways in human cDC2s shape the H. pylori-induced cytokine and chemokine milieu, which plays a pivotal role in the onset of an effective immune response.


Assuntos
Quimiocinas/metabolismo , Citocinas/metabolismo , Células Dendríticas/metabolismo , Células Dendríticas/microbiologia , Receptor 10 Toll-Like/metabolismo , Receptor 2 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismo , Antígenos CD1/metabolismo , Mucosa Gástrica/metabolismo , Infecções por Helicobacter/metabolismo , Helicobacter pylori , Humanos , Inflamação , Mediadores da Inflamação/metabolismo , Leucócitos Mononucleares/citologia , Transdução de Sinais , Neoplasias Gástricas/microbiologia
20.
Nanoscale ; 12(3): 2154-2155, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31912840

RESUMO

Correction for 'Nanoparticle binding attenuates the pathobiology of gastric cancer-associated Helicobacter pylori' by Dana Westmeier et al., Nanoscale, 2018, 10, 1453-1463.

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