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1.
Curr Opin Microbiol ; 71: 102256, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36584489

RESUMO

Cell death in response to infection is conserved across all kingdoms of life. In metazoans, cell death upon bacterial infection is primarily carried out by the cysteine and aspartate protease and receptor-interacting serine/threonine protein kinase families. The Gram-negative bacterial genus Yersinia includes pathogens that cause disease in humans and other animals ranging from plague to gastrointestinal infections. Pathogenic Yersiniae express a type-III secretion system (T3SS), which translocates effectors that disrupt phagocytosis and innate immune signaling to evade immune defenses and replicate extracellularly in infected tissues. Blockade of innate immune signaling, disruption of the actin cytoskeleton, and the membrane-disrupting activity of the T3SS translocon pore, are all sensed by innate immune cells. Here, we discuss recent advances in understanding the pathways that regulate Yersinia-induced cell death, and how manipulation of these cell death pathways over the course of infection promotes bacterial dissemination or host defense.


Assuntos
Morte Celular Regulada , Yersiniose , Humanos , Animais , Yersinia , Sistemas de Secreção Tipo III/metabolismo , Morte Celular , Transdução de Sinais , Proteínas de Bactérias
3.
J Infect Chemother ; 28(11): 1582-1583, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35934232

RESUMO

Antibody titers against the superantigen, Yersinia pseudotuberculosis-derived mitogen, suggestive of mediating Kawasaki disease-like manifestation in Y. pseudotuberculosis infections, in immunoglobulin products were evaluated. Trace, but detectable titer was demonstrated in the products. Thus, attention is required when evaluating anti-Y. pseudotuberculosis-derived mitogen IgG titers in patient sera post intravenous immunoglobulin therapy.


Assuntos
Yersiniose , Infecções por Yersinia pseudotuberculosis , Yersinia pseudotuberculosis , Humanos , Imunoglobulinas Intravenosas/uso terapêutico , Mitógenos/uso terapêutico , Yersinia , Infecções por Yersinia pseudotuberculosis/tratamento farmacológico
4.
PLoS Genet ; 18(7): e1010321, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35901167

RESUMO

The type III secretion system (T3SS) is an appendage used by many bacterial pathogens, such as pathogenic Yersinia, to subvert host defenses. However, because the T3SS is energetically costly and immunogenic, it must be tightly regulated in response to environmental cues to enable survival in the host. Here we show that expression of the Yersinia Ysc T3SS master regulator, LcrF, is orchestrated by the opposing activities of the repressive H-NS/YmoA histone-like protein complex and induction by the iron and oxygen-regulated IscR transcription factor. While deletion of iscR or ymoA has been shown to decrease and increase LcrF expression and type III secretion, respectively, the role of H-NS in this system has not been definitively established because hns is an essential gene in Yersinia. Using CRISPRi knockdown of hns, we show that hns depletion causes derepression of lcrF. Furthermore, we find that while YmoA is dispensable for H-NS binding to the lcrF promoter, YmoA binding to H-NS is important for H-NS repressive activity. We bioinformatically identified three H-NS binding regions within the lcrF promoter and demonstrate binding of H-NS to these sites in vivo using chromatin immunoprecipitation. Using promoter truncation and binding site mutation analysis, we show that two of these H-NS binding regions are important for H-NS/YmoA-mediated repression of the lcrF promoter. Surprisingly, we find that IscR is dispensable for lcrF transcription in the absence of H-NS/YmoA. Indeed, IscR-dependent regulation of LcrF and type III secretion in response to changes in oxygen, such as those Yersinia is predicted to experience during host infection, only occurs in the presence of an H-NS/YmoA complex. These data suggest that, in the presence of host tissue cues that drive sufficient IscR expression, IscR can act as a roadblock to H-NS/YmoA-dependent repression of RNA polymerase at the lcrF promoter to turn on T3SS expression.


Assuntos
Regulação Bacteriana da Expressão Gênica , Yersinia , Proteínas de Bactérias/metabolismo , Histonas/genética , Oxigênio/metabolismo , Yersinia/genética , Yersinia/metabolismo
5.
Int J Mol Sci ; 23(12)2022 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-35743219

RESUMO

Yersinia enterocolitica is a heterogeneous species comprising highly pathogenic, weakly pathogenic and non-pathogenic strains. Previous data suggest that gene exchange may occur in Yersinia. Only scarce information exists about temperate phages of Y. enterocolitica, even though many prophage sequences are present in this species. We have examined 102 pathogenic Y. enterocolitica strains for the presence of inducible prophages by mitomycin C treatment. Ten phages were isolated from nine strains belonging to the bio (B)/serotypes (O) B2/O:5,27, B2/O:9 and 1B/O:8. All phages are myoviruses showing lytic activity only at room temperature. Whole-genome sequencing of the phage genomes revealed that they belong to three groups, which, however, are not closely related to known phages. Group 1 is composed of five phages (type phage: vB_YenM_06.16.1) with genome sizes of 43.8 to 44.9 kb, whereas the four group 2 phages (type phage: vB_YenM_06.16.2) possess smaller genomes of 29.5 to 33.2 kb. Group 3 contains only one phage (vB_YenM_42.18) whose genome has a size of 36.5 kb, which is moderately similar to group 2. The host range of the phages differed significantly. While group 1 phages almost exclusively lysed strains of B2/O:5,27, phages of group 2 and 3 were additionally able to lyse B4/O:3, and some of them even B2/O:9 and 1B/O:8 strains.


Assuntos
Bacteriófagos , Yersinia enterocolitica , Bacteriófagos/genética , Especificidade de Hospedeiro , Análise de Sequência , Yersinia/genética , Yersinia enterocolitica/genética
6.
Nat Commun ; 13(1): 2858, 2022 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-35654781

RESUMO

Several gram-negative bacteria employ type III secretion systems (T3SS) to inject effector proteins into eukaryotic host cells directly from the bacterial cytoplasm. The export gate SctV (YscV in Yersinia) binds substrate:chaperone complexes such as YscX:YscY, which are essential for formation of a functional T3SS. Here, we present structures of the YscX:YscY complex alone and bound to nonameric YscV. YscX binds its chaperone YscY at two distinct sites, resembling the heterotrimeric complex of the T3SS needle subunit with its chaperone and co-chaperone. In the ternary complex the YscX N-terminus, which mediates YscX secretion, occupies a binding site within one YscV that is also used by flagellar chaperones, suggesting the interaction's importance for substrate recognition. The YscX C-terminus inserts between protomers of the YscV ring where the stalk protein binds to couple YscV to the T3SS ATPase. This primary YscV-YscX interaction is essential for the formation of a secretion-competent T3SS.


Assuntos
Proteínas de Bactérias , Chaperonas Moleculares , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Chaperonas Moleculares/metabolismo , Sistemas de Secreção Tipo III/metabolismo , Yersinia/metabolismo
7.
Molecules ; 27(9)2022 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-35566248

RESUMO

A high enzyme-yield strain Yersinia sp. 298 was screened from marine bacteria harvested from the coastal water. The screening conditions were extensive, utilizing hyaluronic acid (HA)/chondroitin sulfate (CS) as the carbon source. A coding gene yshyl8A of the family 8 polysaccharide lyase (PL8) was cloned from the genome of Yersinia sp. 298 and subjected to recombinant expression. The specific activity of the recombinase YsHyl8A was 11.19 U/mg, with an optimal reaction temperature of 40 °C and 50% of its specific activity remaining after thermal incubation at 30 °C for 1 h. In addition, its optimal reaction pH was 7.5, and while it was most stable at pH 6.0 in Na2HPO4-citric acid buffer, it remained highly stable at pH 6.0-11.0. Further, its enzymatic activity was increased five-fold with 0.1 M NaCl. YsHyl8A, as an endo-lyase, can degrade both HA and CS, producing disaccharide end-products. These properties suggested that YsHyl8A possessed both significant alkalophilic and cold-adapted features while being dependent on NaCl, likely resulting from its marine source. Yersinia is a typical fish pathogen, with glycosaminoglycan lyase (GAG lyase) as a potential pathogenic factor, exhibiting strong hyaluronidase and chondroitinase activity. Further research on the pathogenic mechanism of GAG lyase may benefit the prevention and treatment of related diseases.


Assuntos
Glicosaminoglicanos , Liases , Animais , Sulfatos de Condroitina , Ácido Hialurônico/química , Concentração de Íons de Hidrogênio , Polissacarídeo-Liases/química , Cloreto de Sódio , Yersinia/genética , Yersinia/metabolismo
8.
Bull Exp Biol Med ; 172(6): 725-728, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35503586

RESUMO

One of the mechanisms underlying the appearance of chronic infections is transition of pathogens into a non-culturable state, which is largely associated with the use of antibiotics. We studied ultrastructure of dormant bacteria Yersinia pseudotuberculosis obtained from the vegetative form of strain 512 by inhibition with kanamycin. On the model of the causative agent of pseudotuberculosis we showed that transition of prokaryotes to a dormant state occurs through apoptosis of bacteria. Fragmentation and condensation of chromatin with the formation of electron-dense fibrils, clumps and large conglomerates characteristic of apoptosis were found in the nucleoid zone of the cytoplasm of inhibited bacterial cells. These results are of great importance for understanding the mechanisms of the existence of pathogens in different conditions, as well as for identifying the causative agents of infectious diseases.


Assuntos
Infecções por Yersinia pseudotuberculosis , Yersinia pseudotuberculosis , Antibacterianos , Humanos , Yersinia , Yersinia pseudotuberculosis/ultraestrutura , Infecções por Yersinia pseudotuberculosis/microbiologia
9.
PLoS Pathog ; 18(5): e1010251, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35604950

RESUMO

Yersinia enterocolitica employs a type three secretion system (T3SS) to translocate immunosuppressive effector proteins into host cells. To this end, the T3SS assembles a translocon/pore complex composed of the translocator proteins YopB and YopD in host cell membranes serving as an entry port for the effectors. The translocon is formed in a Yersinia-containing pre-phagosomal compartment that is connected to the extracellular space. As the phagosome matures, the translocon and the membrane damage it causes are recognized by the cell-autonomous immune system. We infected cells in the presence of fluorophore-labeled ALFA-tag-binding nanobodies with a Y. enterocolitica strain expressing YopD labeled with an ALFA-tag. Thereby we could record the integration of YopD into translocons and its intracellular fate in living host cells. YopD was integrated into translocons around 2 min after uptake of the bacteria into a phosphatidylinositol-4,5-bisphosphate enriched pre-phagosomal compartment and remained there for 27 min on average. Damaging of the phagosomal membrane as visualized with recruitment of GFP-tagged galectin-3 occurred in the mean around 14 min after translocon formation. Shortly after recruitment of galectin-3, guanylate-binding protein 1 (GBP-1) was recruited to phagosomes, which was accompanied by a decrease in the signal intensity of translocons, suggesting their degradation or disassembly. In sum, we were able for the first time to film the spatiotemporal dynamics of Yersinia T3SS translocon formation and degradation and its sensing by components of the cell-autonomous immune system.


Assuntos
Yersinia pseudotuberculosis , Yersinia , Proteínas da Membrana Bacteriana Externa/metabolismo , Proteínas de Bactérias/metabolismo , Galectina 3 , Sistemas de Secreção Tipo III/metabolismo , Yersinia/metabolismo , Yersinia pseudotuberculosis/metabolismo
10.
Biochim Biophys Acta Proteins Proteom ; 1870(5): 140782, 2022 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-35470106

RESUMO

Protein phosphorylation mediated by protein kinases and phosphatases has a central regulatory function in many cellular processes in eukaryotes and prokaryotes. As a result, several diseases caused by imbalance in phosphorylation levels are known, especially due to protein tyrosine phosphatases (PTPs) activity, an important family of signaling enzymes. Furthermore, over the last decades several studies have shown the main role of PTPs in pathogenic bacteria: they are associated with growth, cell division, cell wall biosynthesis, biofilm formation, metabolic processes, as well as virulence factor. In this way, PTPs have ascended as targets for antibacterial drug design, particularly in view of the antibiotic resistance in pathogenic bacteria, which demands novel therapeutics strategies. Targeting secreted PTPs is an antivirulence strategy to combat the emergence of antimicrobial resistance (AMR). This review focuses on the recent advances in understanding the role of PTPs and the approaches to target them, with an emphasis in Yersinia spp. and Mycobacterium tuberculosis pathogenesis.


Assuntos
Mycobacterium tuberculosis , Desenho de Fármacos , Inibidores Enzimáticos , Proteínas Tirosina Fosfatases , Yersinia/metabolismo
12.
Dig Dis Sci ; 67(12): 5522-5528, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-35357609

RESUMO

INTRODUCTION: Cytolethal distending toxin (Cdt) is one of the bacterial toxins that present in a variety of gram-negative human pathogens, such as E. coli, Salmonella spp., and Campylobacter spp. CDT is composed of three subunits encoded by three adjacent genes, including cdtA, cdtB, and cdtC. cdtB has been shown to have toxic activity and cause DNA damage in host cells. Despite its presence in different bacterial species, the role of CdtB in acute and chronic infections, such as gastroenteritis and irritable bowel syndrome (IBS), is unclear. To analyze this correlation, we studied the prevalence of cdtB among different enteropathogenic bacteria in patients with gastroenteritis and IBS compared with healthy people. MATERIALS AND METHODS: In this cross-sectional descriptive study, 230 stool samples were collected from patients with gastroenteritis, IBS, and healthy people. The presence of CdtB encoding bacteria, including Escherichia coli, Campylobacter spp., Yersinia entercolitica, Providencia alkalifacience, and Salmonella enterica, was examined by polymerase chain reaction using genus-specific primers. RESULTS: Out of 230 stool samples, CdtB encoding Campylobacter spp. were found in 34.6% (52/150), 6.25% (5/80), and 4% (2/50) of the patients with gastroenteritis, IBS, and the control group, respectively. Carriage of CdtB encoding Salmonella enterica was characterized among 5.3% (8/150) of the patients with gastroenteritis and 17.5% (14/80) of the IBS patients. Although none of the patients carried CdtB encoding E. coli and Providencia spp., cdtB of Y. enterocolitica was detected in one of the patients with gastroenteritis (0.6%). Statistical analysis showed significant correlation between infection with CdtB encoding Campylobacter spp. and IBS-D subtype. No significant correlation was found between infection with CdtB encoding bacteria and other clinical and demographic data. CONCLUSION: Our results confirmed a relatively higher frequency of CdtB encoding bacteria in the intestine of patients with gastroenteritis and those with IBS compared with healthy individuals. Regarding the frequency of CdtB encoding Salmonella and Campylobacter bacteria, it was proposed that infection with these enteropathogens could be considered a risk factor for the development or progression of IBS among Iranian patients. Further studies are needed to establish this involvement.


Assuntos
Campylobacter , Gastroenterite , Síndrome do Intestino Irritável , Salmonella enterica , Humanos , Síndrome do Intestino Irritável/epidemiologia , Salmonella enterica/genética , Yersinia , Escherichia coli , Estudos Transversais , Irã (Geográfico) , Campylobacter/genética , Gastroenterite/epidemiologia
13.
Foodborne Pathog Dis ; 19(4): 248-258, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35049363

RESUMO

In Canada, enteric infections cause significant health and economic burden. We evaluated the individual characteristics of laboratory-confirmed cases of Campylobacter spp. (n = 28,728), non-typhoidal Salmonella spp. (n = 22,640), Yersinia spp. (n = 1674), Verotoxin-producing Escherichia coli (VTEC; n = 1340), and Listeria monocytogenes (n = 471), reported between 2010 and 2017 inclusive, in Ontario, Canada (population ∼13,500,000). We calculated overall and pathogen-specific annual and mean incidence rates (IRs) for Ontario. We used multivariable Poisson and negative binomial regression models to estimate incidence rate ratios (IRRs) for years, seasons, age groups, and sexes, and we included two-way age and sex interaction terms in the models. Campylobacter and Salmonella infections had the highest IRs whereas Listeria infections had the lowest IRs. None of the infections showed long-term trends over the 8-year study period; however, rates of all five infections were elevated in the summer. More Salmonella, VTEC, and Listeria infections were linked to disease outbreaks than were Campylobacter and Yersinia infections. Overall, mean IRs of Campylobacter, Salmonella, Yersinia, and VTEC infections were highest in children 0-4 years old, whereas Listeria IRs peaked in adults 60 years and older. Higher mean IRs of Campylobacter were observed in males. No other differences by sex were statistically significant. The same mean rate was observed in both sexes for Listeria. Adjusting for all other factors, significant age- and sex-specific differences in IRs were observed in Campylobacter, Salmonella, and VTEC infection rates. No significant interactions of age and sex were found for Yersinia and Listeria infections. Future research should focus on the pathogen-specific socioeconomic, environmental, or agricultural risk factors that might be responsible for these infections.


Assuntos
Infecções por Campylobacter , Campylobacter , Listeriose , Escherichia coli Shiga Toxigênica , Adulto , Infecções por Campylobacter/epidemiologia , Criança , Pré-Escolar , Feminino , Humanos , Incidência , Lactente , Recém-Nascido , Listeriose/epidemiologia , Masculino , Ontário/epidemiologia , Fatores de Risco , Salmonella , Estações do Ano , Yersinia
14.
Environ Sci Pollut Res Int ; 29(22): 33713-33724, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35029822

RESUMO

Heat- and pH-stable phytase efficiently hydrolyzes phytic acid. In this research, heat- and pH-stable mutant phytases, T83R, L287R, and T83R/L287R were generated by site-directed mutagenesis from Yersinia intermedia. After the induction and expression of recombinant wild-type and mutant phytases in E. coli BL21, the enzymes were purified using nickel sepharose affinity chromatography, and characterized kinetically and thermodynamically using spectroscopy methods. The mutants showed optimum activity at pH 5.15 and 55-61 °C. The catalytic efficiencies of T83R, L287R, T83R/L287R, and wild-type phytases were calculated to be 2941, 29346, 4906, and 6917 mmol/L-1s-1, respectively. Moreover, after the incubation of T83R, L287R, wild-type, and T83R/ L287R phytases at 100 °C for 1 h, the enzymes retained 22, 5, 4, and 2% of their initial activities, respectively. In addition, T83R, T83R/L287R, L287R, and wild-type phytases retained 82, 44, 16 as well as 11% of their initial activities after 1 h at pH 5.15, respectively. Among these mutants, T83R mutant showed 18% increase in thermal stability, 71% increase in pH stability, and +0.103 KJ/mole increase in ΔΔG, while the catalytic efficiency and ΔΔG value of L287R mutant increased by 4 times and +0.0903 KJ/mole, respectively. Thus, the mutants have the potential to be used in feed industries to increase the bioavailability of minerals while decreasing soil and water pollution.


Assuntos
6-Fitase , 6-Fitase/química , Estabilidade Enzimática , Escherichia coli/metabolismo , Concentração de Íons de Hidrogênio , Yersinia/química
15.
PLoS One ; 17(1): e0263019, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35077520

RESUMO

Bacterial protein secretion is crucial to the maintenance of viability and pathogenicity. Although many bacterial secretion systems have been identified, the underlying mechanisms regulating their expression are less well explored. Yersinia entomophaga MH96, an entomopathogenic bacterium, releases an abundance of proteins including the Yen-Tc into the growth medium when cultured in Luria Bertani broth at ≤ 25°C. Through the development of a high-throughput exoproteome screening assay (HESA), genes involved in MH96 exoprotein production were identified. Of 4,080 screened transposon mutants, 34 mutants exhibited a decreased exoprotein release, and one mutation located in the intergenic region of the Yen-Tc operon displayed an elevated exoprotein release relative to the wild-type strain MH96. DNA sequencing revealed several transposon insertions clustered in gene regions associated with lipopolysaccharide (LPSI and LPSII), and N-acyl-homoserine lactone synthesis (quorum sensing). Twelve transposon insertions were located within transcriptional regulators or intergenic regions. The HESA will have broad applicability for identifying genes associated with exoproteome production in a range of microorganisms.


Assuntos
Proteínas de Bactérias , Regulação Bacteriana da Expressão Gênica , Proteoma , Yersinia , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Proteoma/genética , Proteoma/metabolismo , Yersinia/genética , Yersinia/metabolismo
16.
Cell Death Differ ; 29(2): 306-322, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34999730

RESUMO

Phosphorylation of the pseudokinase mixed lineage kinase domain-like protein (MLKL) by the protein kinase RIPK3 targets MLKL to the cell membrane, where it triggers necroptotic cell death. We report that conjugation of K63-linked polyubiquitin chains to distinct lysine residues in the N-terminal HeLo domain of phosphorylated MLKL (facilitated by the ubiquitin ligase ITCH that binds MLKL via a WW domain) targets MLKL instead to endosomes. This results in the release of phosphorylated MLKL within extracellular vesicles. It also prompts enhanced endosomal trafficking of intracellular bacteria such as Listeria monocytogenes and Yersinia enterocolitica to the lysosomes, resulting in decreased bacterial yield. Thus, MLKL can be directed by specific covalent modifications to differing subcellular sites, whence it signals either for cell death or for non-deadly defense mechanisms.


Assuntos
Listeria , Yersinia , Endossomos/metabolismo , Listeria/metabolismo , Lisossomos/metabolismo , Fosforilação , Proteína Serina-Treonina Quinases de Interação com Receptores/metabolismo , Ubiquitinação , Yersinia/metabolismo
17.
Braz. j. biol ; 82: e237098, 2022. graf
Artigo em Inglês | LILACS | ID: biblio-1153483

RESUMO

Abstract Endosymbiont bacteria can affect biological parameters and reduce the effectiveness of natural enemies in controlling the target insect. The objective of this work was to identify endosymbiont bacteria in Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae), the main natural enemy used to manage Gonipterus platensis (Marelli, 1926) (Coleoptera: Curculionidae). Genomic DNA from six A. nitens populations was extracted and polymerase chain reactions (PCR) were performed with the primers to detect endosymbiont bacteria in this insect. The PCR products were amplified, sequenced, and compared with sequences deposited in the GenBank for the bacteria identification. All A. nitens populations had the bacterium Yersinia massiliensis (Enterobacteriales: Enterobacteriaceae). This bacterium was originally described as free-living, and it is associated with and composes part of the A. nitens microbiota. This is the first report of Y. massiliensis in an insect host.


Resumo As bactérias endossimbiontes podem afetar os parâmetros biológicos e reduzirem a eficácia de inimigos naturais no controle do inseto alvo. O objetivo deste trabalho foi identificar bactérias endossimbiontes em Anaphes nitens (Girault, 1928) (Hymenoptera: Mymaridae), o principal inimigo natural usado no manejo de Gonipterus platensis (Marelli, 1926) (Coleoptera: Curculionidae). O DNA genômico de seis populações de A. nitens foi extraído e as reações em cadeia da polimerase (PCR) realizadas com os primers para detectar bactérias endossimbiontes neste inseto. Os produtos de PCR foram amplificados, sequenciados e comparados com as sequências depositadas no GenBank para identificação das bactérias. Todas as populações de A. nitens tinham a bactéria Yersinia massiliensis (Enterobacteriales: Enterobacteriaceae). Esta bactéria foi originalmente descrita como de vida livre e está associada e compõe parte da microbiota de A. nitens. Este é o primeiro relato de Y. massiliensis em um hospedeiro.


Assuntos
Animais , Gorgulhos , Himenópteros/genética , Yersinia/genética , Enterobacteriaceae/genética
18.
Infect Immun ; 89(12): e0043021, 2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34543120

RESUMO

Despite the maintenance of YopP/J alleles throughout the human-pathogenic Yersinia lineage, the benefit of YopP/J-induced phagocyte death for Yersinia pathogenesis in animals is not obvious. To determine how the sequence divergence of YopP/J has impacted Yersinia virulence, we examined protein polymorphisms in this type III secreted effector protein across 17 Yersinia species and tested the consequences of polymorphism in a murine model of subacute systemic yersiniosis. Our evolutionary analysis revealed that codon 177 has been subjected to positive selection; the Yersinia enterocolitica residue had been altered from a leucine to a phenylalanine in nearly all Yersinia pseudotuberculosis and Yersinia pestis strains examined. Despite this change being minor, as both leucine and phenylalanine have hydrophobic side chains, reversion of YopJF177 to the ancestral YopJL177 variant yielded a Y. pseudotuberculosis strain with enhanced cytotoxicity toward macrophages, consistent with previous findings. Surprisingly, expression of YopJF177L in the mildly attenuated ksgA- background rendered the strain completely avirulent in mice. Consistent with this hypothesis that YopJ activity relates indirectly to Yersinia pathogenesis in vivo, ksgA- strains lacking functional YopJ failed to kill macrophages but actually regained virulence in animals. Also, treatment with the antiapoptosis drug suramin prevented YopJ-mediated macrophage cytotoxicity and enhanced Y. pseudotuberculosis virulence in vivo. Our results demonstrate that Yersinia-induced cell death is detrimental for bacterial pathogenesis in this animal model of illness and indicate that positive selection has driven YopJ/P and Yersinia evolution toward diminished cytotoxicity and increased virulence, respectively.


Assuntos
Proteínas de Bactérias/genética , Regulação Bacteriana da Expressão Gênica , Interações Hospedeiro-Patógeno , Yersiniose/microbiologia , Yersinia/fisiologia , Animais , Proteínas de Bactérias/metabolismo , Suscetibilidade a Doenças , Humanos , Mutação , Virulência/genética , Fatores de Virulência , Yersinia/patogenicidade
19.
Toxins (Basel) ; 13(12)2021 12 15.
Artigo em Inglês | MEDLINE | ID: mdl-34941738

RESUMO

The cytotoxic necrotizing factors (CNFs) are a family of Rho GTPase-activating single-chain exotoxins that are produced by several Gram-negative pathogenic bacteria. Due to the pleiotropic activities of the targeted Rho GTPases, the CNFs trigger multiple signaling pathways and host cell processes with diverse functional consequences. They influence cytokinesis, tissue integrity, cell barriers, and cell death, as well as the induction of inflammatory and immune cell responses. This has an enormous influence on host-pathogen interactions and the severity of the infection. The present review provides a comprehensive insight into our current knowledge of the modular structure, cell entry mechanisms, and the mode of action of this class of toxins, and describes their influence on the cell, tissue/organ, and systems levels. In addition to their toxic functions, possibilities for their use as drug delivery tool and for therapeutic applications against important illnesses, including nervous system diseases and cancer, have also been identified and are discussed.


Assuntos
Toxinas Bacterianas/farmacologia , Exotoxinas/farmacologia , Proteínas rho de Ligação ao GTP/metabolismo , Escherichia coli/metabolismo , Exotoxinas/metabolismo , Yersinia/metabolismo
20.
Mol Cell ; 81(24): 5039-5051.e5, 2021 12 16.
Artigo em Inglês | MEDLINE | ID: mdl-34784509

RESUMO

Cyclic oligonucleotide-based antiphage signaling systems (CBASS) are antiviral defense operons that protect bacteria from phage replication. Here, we discover a widespread class of CBASS transmembrane (TM) effector proteins that respond to antiviral nucleotide signals and limit phage propagation through direct membrane disruption. Crystal structures of the Yersinia TM effector Cap15 reveal a compact 8-stranded ß-barrel scaffold that forms a cyclic dinucleotide receptor domain that oligomerizes upon activation. We demonstrate that activated Cap15 relocalizes throughout the cell and specifically induces rupture of the inner membrane. Screening for active effectors, we identify the function of distinct families of CBASS TM effectors and demonstrate that cell death via disruption of inner-membrane integrity is a common mechanism of defense. Our results reveal the function of the most prominent class of effector protein in CBASS immunity and define disruption of the inner membrane as a widespread strategy of abortive infection in bacterial phage defense.


Assuntos
Proteínas de Bactérias/metabolismo , Bacteriófagos/patogenicidade , Membrana Celular/virologia , Escherichia coli/virologia , Yersinia/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Bacteriófagos/imunologia , Morte Celular , Membrana Celular/genética , Membrana Celular/metabolismo , Escherichia coli/genética , Escherichia coli/imunologia , Escherichia coli/metabolismo , Interações Hospedeiro-Patógeno , Ligantes , Conformação Proteica , Multimerização Proteica , Transporte Proteico , Transdução de Sinais , Relação Estrutura-Atividade , Yersinia/genética
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