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1.
PLoS One ; 17(8): e0267859, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35939437

RESUMO

Clostridioides difficile infection is a global health threat and remains the primary cause of hospital-acquired infections worldwide. The burgeoning incidence and severity of infections coupled with high rates of recurrence have created an urgent need for novel therapeutics. Here, we report a novel natural product scaffold as a potential anticlostridial lead with antivirulence properties and potent activity both in vitro and in vivo. A whole cell phenotypic screening of 1,000 purified natural products identified 6 compounds with potent activity against C. difficile (minimum inhibitory concentration (MIC) range from 0.03 to 2 µg/ml). All these 6 compounds were non-toxic to human colorectal cells. The natural product compounds also inhibited the production of key toxins, TcdA and TcdB, the key virulence determinants of C. difficile infection pathology. Additionally, the compounds exhibited rapid bactericidal activity and were superior to the standard-of-care antibiotic vancomycin, in reducing a high inoculum of C. difficile in vitro. Furthermore, a murine model of C. difficile infection revealed that compound NP-003875 conferred 100% protection to the infected mice from clinical manifestations of the disease. Collectively, the current study lays the foundation for further investigation of the natural product NP-003875 as a potential therapeutic choice for C. difficile infection.


Assuntos
Toxinas Bacterianas , Produtos Biológicos , Clostridioides difficile , Infecções por Clostridium , Animais , Proteínas de Bactérias/toxicidade , Toxinas Bacterianas/toxicidade , Produtos Biológicos/farmacologia , Produtos Biológicos/uso terapêutico , Clostridioides , Infecções por Clostridium/tratamento farmacológico , Infecções por Clostridium/patologia , Enterotoxinas/toxicidade , Humanos , Camundongos
2.
Appl Environ Microbiol ; 88(13): e0040522, 2022 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-35730937

RESUMO

Bacillus cereus sensu lato (s.l.) includes foodborne pathogens, as well as beneficial microorganisms, such as bioinsecticides. Some of the beneficial and commercially used B. cereus s.l. strains have been shown to carry enterotoxin genes, the products of which can cause toxicoinfection in humans. Furthermore, recent epidemiological reports indicated that some bioinsecticidal strains have been linked with foodborne illness outbreaks. This demonstrates the need for improved surveillance of B. cereus s.l., which includes characterization of isolates' virulence capacity. However, the prediction of virulence capacity of B. cereus s.l. strains is challenging. Genetic screening for enterotoxin gene presence has proven to be insufficient for accurate discrimination between virulent and avirulent strains, given that nearly all B. cereus s.l. strains carry at least one enterotoxin gene. Furthermore, complex regulatory networks governing the expression of enterotoxins, and potential synergistic interactions between enterotoxins and other virulence factors make the prediction of toxicoinfection based on isolates' genome sequences challenging. In this review, we summarize and synthesize the current understanding of the regulation of enterotoxins associated with the B. cereus s.l. toxicoinfection and identify gaps in the knowledge that need to be addressed to facilitate identification of genetic markers predictive of cytotoxicity and toxicoinfection.


Assuntos
Enterotoxinas , Doenças Transmitidas por Alimentos , Bacillus cereus/metabolismo , Enterotoxinas/genética , Enterotoxinas/metabolismo , Enterotoxinas/toxicidade , Microbiologia de Alimentos , Humanos , Virulência , Fatores de Virulência/genética
3.
Curr Protein Pept Sci ; 23(3): 192-209, 2022 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-35585826

RESUMO

BACKGROUND: Clostridiodes (or Clostridium) difficile is a spore-forming, Gram-positive anaerobic bacterium that may cause symptoms ranging from diarrhea to pseudomembranous colitis. During the C. difficile infection (CDI), the two primary bacterial toxins, toxin A (TcdA) or toxin B (TcdB), disrupt host cell function mainly through the inactivation of small GTPases that regulate the actin cytoskeleton. Both toxins have complex structural organization containing several functional domains. METHODS: Analytical bioinformatics tools are used to compare the extent of disorder within TcdA and TcdB proteins, and to see if the existence of structural disorder can be used to explain the difference in the functionality of these toxins. RESULTS: This paper's aim is to offer an overall review of the structural and functional differences between TcdA and TcdB. CONCLUSION: Results of our multifactorial bioinformatics analysis revealed that intrinsic disorder may play a role in the multifunctionality of C. difficile major toxins TcdA and TcdB, suggesting that intrinsic disorder may be related to their pathogenic mechanisms.


Assuntos
Toxinas Bacterianas , Clostridioides difficile , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Toxinas Bacterianas/toxicidade , Composição de Bases , Enterotoxinas/metabolismo , Enterotoxinas/toxicidade , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA
4.
Endocrinology ; 163(4)2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35266539

RESUMO

Enterotoxigenic Escherichia coli (ETEC)-derived purified heat-stable enterotoxin b (STb) is responsible for secretory diarrhea in livestock and humans. STb disrupts intestinal fluid homeostasis, epithelial barrier function, and promotes cell death. Glucagon-like peptide-2 (GLP-2) is a potent intestinotrophic hormone secreted by enteroendocrine L cells. GLP-2 enhances crypt cell proliferation, epithelial barrier function, and inhibits enterocyte apoptosis. Whether STb can affect GLP-2 producing L cells remains to be elucidated. First, secreted-His-labeled STb from transformed E coli was collected and purified. When incubated with L-cell models (GLUTag, NCI-H716, and secretin tumor cell line [STC-1]), fluorescent immunocytochemistry revealed STb was internalized and was differentially localized in the cytoplasm and nucleus. Cell viability experiments with neutral red and resazurin revealed that STb was toxic in all but the GLUTag cells. STb stimulated 2-hour GLP-2 secretion in all cell models. Interestingly, GLUTag cells produced the highest amount of GLP-2 when treated with STb, demonstrating an inverse relationship in GLP-2 secretion and cell toxicity. To demonstrate a protective role for GLP-2, GLUTag-conditioned media (rich in GLP-2) blocked STb toxicity in STC-1 cells. Confirming a protective role of GLP-2, teduglutide was able to improve cell viability in cells treated with H2O2. In conclusion, STb interacts with the L cell, stimulates secretion, and may induce toxicity if GLP-2 is not produced at high levels. GLP-2 or receptor agonists have the ability to improve cell viability in response to toxins. These results suggest that GLP-2 secretion can play a protective role during STb intoxication. This work supports future investigation into the use of GLP-2 therapies in enterotoxigenic-related diseases.


Assuntos
Enterotoxinas , Peptídeo 2 Semelhante ao Glucagon , Animais , Células Enteroendócrinas/metabolismo , Enterotoxinas/metabolismo , Enterotoxinas/toxicidade , Escherichia coli/metabolismo , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Peptídeo 2 Semelhante ao Glucagon/metabolismo , Peptídeo 2 Semelhante ao Glucagon/farmacologia , Temperatura Alta , Humanos , Peróxido de Hidrogênio/metabolismo , Células L , Camundongos
5.
Cells ; 11(5)2022 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-35269525

RESUMO

Claudins are a family of integral membrane proteins that enable epithelial cell/cell interactions by localizing to and driving the formation of tight junctions. Via claudin self-assembly within the membranes of adjoining cells, their extracellular domains interact, forming barriers to the paracellular transport of small molecules and ions. The bacterium Clostridium perfringens causes prevalent gastrointestinal disorders in mammals by employing an enterotoxin (CpE) that targets claudins. CpE binds to claudins at or near tight junctions in the gut and disrupts their barrier function, potentially by disabling their assembly or via cell signaling means-the mechanism(s) remain unclear. CpE ultimately destroys claudin-expressing cells through the formation of a cytotoxic membrane-penetrating ß-barrel pore. Structures obtained by X-ray crystallography of CpE, claudins, and claudins in complex with CpE fragments have provided the structural bases of claudin and CpE functions, revealing potential mechanisms for the CpE-mediated disruption of claudin-made tight junctions. This review highlights current progress in this space-what has been discovered and what remains unknown-toward efforts to elucidate the molecular mechanism of CpE disruption of tight junction barriers. It further underscores the key insights obtained through structure that are being applied to develop CpE-based therapeutics that combat claudin-overexpressing cancers or modulate tight junction barriers.


Assuntos
Claudinas , Junções Íntimas , Animais , Biologia , Claudinas/metabolismo , Enterotoxinas/toxicidade , Mamíferos/metabolismo , Junções Íntimas/metabolismo
6.
Arch Toxicol ; 96(5): 1213-1225, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35226135

RESUMO

Enterotoxigenic Escherichia coli (ETEC) in humans and animals colonizes the intestine and thereafter secrets heat-stable enterotoxin (ST) with or without heat-labile enterotoxin (LT), which triggers massive fluid and electrolyte secretion into the gut lumen. The crosstalk between the cyclic nucleotide-dependent protein kinase/cystic fibrosis transmembrane conductance regulator (cAMP or cGMP/CFTR) pathway involved in ETEC-induced diarrhea channels, and the canonical Wnt/ß-catenin signaling pathway leads to changes in intestinal stem cell (ISC) fates, which are strongly associated with developmental disorders caused by diarrhea. We review how alterations in enterotoxin-activated ion channel pathways and the canonical Wnt/ß-catenin signaling pathway can explain inhibited intestinal epithelial activity, characterize alterations in the crosstalk of cyclic nucleotides, and predict harmful effects on ISCs in targeted therapy. Besides, we discuss current deficits in the understanding of enterotoxin-intestinal epithelial cell activity relationships that should be considered when interpreting sequelae of diarrhea.


Assuntos
Escherichia coli Enterotoxigênica , Infecções por Escherichia coli , Enteropatias , Animais , Diarreia/induzido quimicamente , Escherichia coli Enterotoxigênica/metabolismo , Enterotoxinas/metabolismo , Enterotoxinas/toxicidade , Proteínas de Escherichia coli/metabolismo , Intestinos , Nucleotídeos Cíclicos/metabolismo , Nucleotídeos Cíclicos/farmacologia , Células-Tronco/metabolismo , Via de Sinalização Wnt
7.
PLoS Pathog ; 18(2): e1010323, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-35176123

RESUMO

Clostridioides difficile infection (CDI) is the leading cause of nosocomial diarrhea and pseudomembranous colitis in the USA. In addition to these symptoms, patients with CDI can develop severe inflammation and tissue damage, resulting in life-threatening toxic megacolon. CDI is mediated by two large homologous protein toxins, TcdA and TcdB, that bind and hijack receptors to enter host cells where they use glucosyltransferase (GT) enzymes to inactivate Rho family GTPases. GT-dependent intoxication elicits cytopathic changes, cytokine production, and apoptosis. At higher concentrations TcdB induces GT-independent necrosis in cells and tissue by stimulating production of reactive oxygen species via recruitment of the NADPH oxidase complex. Although GT-independent necrosis has been observed in vitro, the relevance of this mechanism during CDI has remained an outstanding question in the field. In this study we generated novel C. difficile toxin mutants in the hypervirulent BI/NAP1/PCR-ribotype 027 R20291 strain to test the hypothesis that GT-independent epithelial damage occurs during CDI. Using the mouse model of CDI, we observed that epithelial damage occurs through a GT-independent process that does not involve immune cell influx. The GT-activity of either toxin was sufficient to cause severe edema and inflammation, yet GT activity of both toxins was necessary to produce severe watery diarrhea. These results demonstrate that both TcdA and TcdB contribute to disease pathogenesis when present. Further, while inactivating GT activity of C. difficile toxins may suppress diarrhea and deleterious GT-dependent immune responses, the potential of severe GT-independent epithelial damage merits consideration when developing toxin-based therapeutics against CDI.


Assuntos
Toxinas Bacterianas , Clostridioides difficile , Infecções por Clostridium , Animais , Anticorpos Antibacterianos , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/metabolismo , Infecções por Clostridium/patologia , Diarreia , Enterotoxinas/metabolismo , Enterotoxinas/toxicidade , Glucosiltransferases/genética , Glucosiltransferases/metabolismo , Humanos , Inflamação , Camundongos , Necrose
8.
Toxins (Basel) ; 14(2)2022 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-35202145

RESUMO

Yersinia (Y.) enterocolitica, an etiological agent of yersiniosis, is a bacterium whose pathogenicity is determined, among other things, by its ability to produce toxins. The aim of this article was to present the most important toxins that are produced by biotype 1A strains of Y. enterocolitica, and to discuss their role in the pathogenesis of yersiniosis. Y. enterocolitica biotype 1A strains are able to synthesize variants of thermostable YST enterotoxin and play a key role in the pathogenesis of yersiniosis. Biotype 1A strains of Y. enterocolitica also produce Y. enterocolitica pore-forming toxins, YaxA and YaxB. These toxins form pores in the cell membrane of host target cells and cause osmotic lysis, which is of particular importance in systemic infections. Insecticidal toxin complex genes have been detected in some clinical biotype 1A strains of Y. enterocolitica. However, their role has not yet been fully elucidated. Strains belonging to biotype 1A have long been considered non-pathogenic. This view is beginning to change due to the emerging knowledge about the toxigenic potential of these bacteria and their ability to overcome the defense barriers of the host organism.


Assuntos
Yersinia enterocolitica , Animais , Toxinas Bacterianas/biossíntese , Toxinas Bacterianas/toxicidade , Enterotoxinas/biossíntese , Enterotoxinas/toxicidade , Humanos , Virulência , Yersinia enterocolitica/genética , Yersinia enterocolitica/metabolismo , Yersinia enterocolitica/patogenicidade
9.
Cell Rep ; 38(1): 110172, 2022 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-34986351

RESUMO

During the 2013-2016 West African (WA) Ebola virus (EBOV) outbreak, severe gastrointestinal symptoms were common in patients and associated with poor outcome. Delta peptide is a conserved product of post-translational processing of the abundant EBOV soluble glycoprotein (sGP). The murine ligated ileal loop model was used to demonstrate that delta peptide is a potent enterotoxin. Dramatic intestinal fluid accumulation follows injection of biologically relevant amounts of delta peptide into ileal loops, along with gross alteration of villous architecture and loss of goblet cells. Transcriptomic analyses show that delta peptide triggers damage response and cell survival pathways and downregulates expression of transporters and exchangers. Induction of diarrhea by delta peptide occurs via cellular damage and regulation of genes that encode proteins involved in fluid secretion. While distinct differences exist between the ileal loop murine model and EBOV infection in humans, these results suggest that delta peptide may contribute to EBOV-induced gastrointestinal pathology.


Assuntos
Ebolavirus/metabolismo , Enterotoxinas/toxicidade , Gastroenterite/virologia , Doença pelo Vírus Ebola/patologia , Proteínas do Envelope Viral/toxicidade , Animais , Diarreia/virologia , Feminino , Gastroenterite/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C
10.
Toxins (Basel) ; 14(1)2022 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-35051006

RESUMO

Staphylococcal enterotoxin A (SEA), the toxin protein secreted by Staphylococcus aureus, can cause staphylococcal food poisoning outbreaks and seriously threaten global public health. However, little is known about the pathogenesis of SEA in staphylococcal foodborne diseases. In this study, the effect of SEA on intestinal barrier injury and NLRP3 inflammasome activation was investigated by exposing BALB/c mice to SEA with increasing doses and a potential toxic mechanism was elucidated. Our findings suggested that SEA exposure provoked villi injury and suppressed the expression of ZO-1 and occludin proteins, thereby inducing intestinal barrier dysfunction and small intestinal injury in mice. Concurrently, SEA significantly up-regulated the expression of NLRP3 inflammasome-associated proteins and triggered the mitogen-activated protein kinase (MAPK) and nuclear factor kappa-B (NF-κB) signaling pathways in jejunum tissues. Notably, selective inhibitors of MAPKs and NF-κB p65 ameliorated the activation of NLRP3 inflammasome stimulated by SEA, which further indicated that SEA could activate NLRP3 inflammasome through NF-κB/MAPK pathways. In summary, SEA was first confirmed to induce intestinal barrier dysfunction and activate NLRP3 inflammasome via NF-κB/MAPK signaling pathways. These findings will contribute to a more comprehensive understanding of the pathogenesis of SEA and related drug-screening for the treatment and prevention of bacteriotoxin-caused foodborne diseases via targeting specific pathways.


Assuntos
Enterotoxinas/toxicidade , Contaminação de Alimentos , Inflamassomos/metabolismo , Enteropatias/fisiopatologia , Mucosa Intestinal/efeitos dos fármacos , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Transdução de Sinais/efeitos dos fármacos , Staphylococcus/química , Animais , Modelos Animais de Doenças , Doenças Transmitidas por Alimentos/fisiopatologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , NF-kappa B/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismo
11.
Toxins (Basel) ; 14(1)2022 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-35051039

RESUMO

Foodborne diseases affect an estimated 600 million people worldwide annually, with the majority of these illnesses caused by Norovirus, Vibrio, Listeria, Campylobacter, Salmonella, and Escherichia coli. To elicit infections in humans, bacterial pathogens express a combination of virulence factors and toxins. AB5 toxins are an example of such toxins that can cause various clinical manifestations, including dehydration, diarrhea, kidney damage, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Treatment of most bacterial foodborne illnesses consists of fluid replacement and antibiotics. However, antibiotics are not recommended for infections caused by Shiga toxin-producing E. coli (STEC) because of the increased risk of HUS development, although there are conflicting views and results in this regard. Lack of effective treatment strategies for STEC infections pose a public health threat during outbreaks; therefore, the debate on antibiotic use for STEC infections could be further explored, along with investigations into antibiotic alternatives. The overall goal of this review is to provide a succinct summary on the mechanisms of action and the pathogenesis of AB5 and related toxins, as expressed by bacterial foodborne pathogens, with a primary focus on Shiga toxins (Stx). The role of Stx in human STEC disease, detection methodologies, and available treatment options are also briefly discussed.


Assuntos
Enterotoxinas/toxicidade , Infecções por Escherichia coli/microbiologia , Doenças Transmitidas por Alimentos/microbiologia , Toxinas Shiga/toxicidade , Escherichia coli Shiga Toxigênica/fisiologia , Humanos
12.
Sci Rep ; 12(1): 34, 2022 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-34997016

RESUMO

Cholera toxin (CT) and Escherichia coli heat-labile enterotoxin (LT) are structurally similar AB5-type protein toxins. They move from the cell surface to the endoplasmic reticulum where the A1 catalytic subunit is separated from its holotoxin by protein disulfide isomerase (PDI), thus allowing the dissociated A1 subunit to enter the cytosol for a toxic effect. Despite similar mechanisms of toxicity, CT is more potent than LT. The difference has been attributed to a more stable domain assembly for CT as compared to LT, but this explanation has not been directly tested and is arguable as toxin disassembly is an indispensable step in the cellular action of these toxins. We show here that PDI disassembles CT more efficiently than LT, which provides a possible explanation for the greater potency of the former toxin. Furthermore, direct examination of CT and LT domain assemblies found no difference in toxin stability. Using novel analytic geometry approaches, we provide a detailed characterization of the positioning of the A subunit with respect to the B pentamer and demonstrate significant differences in the interdomain architecture of CT and LT. Protein docking analysis further suggests that these global structural differences result in distinct modes of PDI-toxin interactions. Our results highlight previously overlooked structural differences between CT and LT that provide a new model for the PDI-assisted disassembly and differential potency of these toxins.


Assuntos
Toxina da Cólera/química , Toxina da Cólera/metabolismo , Enterotoxinas/química , Enterotoxinas/metabolismo , Glicosídeos/química , Glicosídeos/metabolismo , Isomerases de Dissulfetos de Proteínas/metabolismo , Triterpenos/química , Triterpenos/metabolismo , Domínio Catalítico , Toxina da Cólera/toxicidade , Enterotoxinas/toxicidade , Escherichia coli/genética , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Temperatura Alta , Simulação de Acoplamento Molecular , Isomerases de Dissulfetos de Proteínas/química , Estabilidade Proteica
13.
J Appl Toxicol ; 42(7): 1205-1217, 2022 07.
Artigo em Inglês | MEDLINE | ID: mdl-35080034

RESUMO

Lipopolysaccharide (LPS) is one of the main constituents of the cell wall in Gram-negative bacteria. Staphylococcal enterotoxin B (SEB) is produced by the Gram-positive opportunistic pathogen, Staphylococcus aureus. Emerging evidence suggests that intraperitoneal injection of LPS combined with low-dose aerosolized SEB exposure can cause severe lung injury and even death, while SEB or LPS alone cause neither mortality nor severe pulmonary symptoms in mice. However, pulmonary effects from exposure to aerosolized SEB potentiated by LPS have not been evaluated. This study investigates the global transcriptome profile of lung tissue in mice after exposure to aerosolized SEB potentiated by LPS or LPS alone. A mouse model of intratracheal exposure to LPS-potentiated aerosolized SEB is established and described through histological examination. Transcriptome analysis revealed LPS-potentiated aerosolized SEB affected mouse lungs within 72 h post-SEB inhalation, gradually causing lung injury starting from 24 h post inhalation. Hub genes leading to lung injury at 48 h post inhalation have been identified. Flow cytometry revealed that LPS potentiation of low-dose SEB produces a superantigen response that T cells expressing a particular T cell receptor Vß induces a proliferation response by 72 h post inhalation in the lungs of mice. This study represents the first research to investigate pulmonary transcriptional responses of LPS-potentiated aerosolized low-dose SEB exposure. This research helps to elucidate the molecular mechanisms underlying the process by which the two bacterial components combined to produce lung damage and provides an insight into potential treatments for alleviating inflammation of the lung when coinfection is present.


Assuntos
Lipopolissacarídeos , Lesão Pulmonar , Animais , Modelos Animais de Doenças , Enterotoxinas/genética , Enterotoxinas/toxicidade , Lipopolissacarídeos/toxicidade , Pulmão/patologia , Lesão Pulmonar/patologia , Camundongos , Camundongos Endogâmicos BALB C , Transcriptoma
14.
J Invest Dermatol ; 142(4): 1032-1039.e6, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-34606884

RESUMO

A potential role of Staphylococcus aureus in bullous pemphigoid was explored by examining the colonization rate in patients with new-onset disease compared with that in age- and sex-matched controls. S. aureus colonization was observed in 85% of bullous pemphigoid lesions, 3-6-fold higher than the nares or unaffected skin from the same patients (P ≤ 0.003) and 6-fold higher than the nares or skin of controls (P ≤ 0.0015). Furthermore, 96% of the lesional isolates produced the toxic shock syndrome toxin-1 superantigen, and most of these additionally exhibited homogeneous expression of the enterotoxin gene cluster toxins. Toxic shock syndrome toxin-1‒neutralizing antibodies were not protective against colonization. However, S. aureus colonization was not observed in patients who had recently received antibiotics, and the addition of antibiotics with staphylococcal coverage eliminated S. aureus and resulted in clinical improvement. This study shows that toxic shock syndrome toxin-1‒positive S. aureus is prevalent in bullous pemphigoid lesions and suggests that early implementation of antibiotics may be of benefit. Furthermore, our results suggest that S. aureus colonization could provide a source of infection in patients with bullous pemphigoid, particularly in the setting of high-dose immunosuppression.


Assuntos
Penfigoide Bolhoso , Infecções Estafilocócicas , Antibacterianos/uso terapêutico , Toxinas Bacterianas , Enterotoxinas/toxicidade , Humanos , Penfigoide Bolhoso/tratamento farmacológico , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/patologia , Staphylococcus aureus/metabolismo , Superantígenos/genética
15.
Food Funct ; 12(19): 9248-9260, 2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34606540

RESUMO

Pathogenesis of C. difficile in the intestine is associated with the secretion of toxins which can damage the intestinal epithelial layer and result in diseases such as diarrhoea. Treatment for C. difficile infections consists of antibiotics which, however, have non-specific microbiocidal effects and may cause intestinal dysbiosis which results in subsequent health issues. Therefore, alternative treatments to C. difficile infections are required. We investigated whether different black soldier fly- and mealworm-derived fractions, after applying the INFOGEST digestion protocol, could counteract C. difficile toxin A-mediated barrier damage of small intestinal Caco-2 cells. Treatment and pre-treatment with insect-derived fractions significantly (p < 0.05) mitigated the decrease of the transepithelial electrical resistance (TEER) of Caco-2 cells induced by C. difficile toxin A. In relation to these effects, RNA sequencing data showed an increased transcription of cell junctional and proliferation protein genes in Caco-2 cells. Furthermore, the transcription of genes regulating immune signalling was also increased. To identify whether this resulted in immune activation we used a Caco-2/THP-1 co-culture model where the cells were only separated by a permeable membrane. However, the insect-derived fractions did not change the basolateral secreted IL-8 levels in this model. To conclude, our findings suggest that black soldier fly- and mealworm-derived fractions can attenuate C. difficile induced intestinal barrier disruption and they might be promising tools to reduce the symptoms of C. difficile infections.


Assuntos
Toxinas Bacterianas/toxicidade , Proliferação de Células/genética , Enterotoxinas/toxicidade , Insetos , Junções Intercelulares/genética , Mucosa Intestinal/fisiologia , Intestino Delgado/citologia , Transcrição Genética , Animais , Células CACO-2 , Clostridioides difficile , Técnicas de Cocultura , Besouros , Dípteros , Células Epiteliais/fisiologia , Humanos , Imunidade/genética , Imunomodulação , Proteínas de Insetos/farmacologia , Mucosa Intestinal/citologia , Intestino Delgado/fisiologia , Macrófagos , RNA-Seq , Células THP-1
16.
Toxins (Basel) ; 13(9)2021 08 29.
Artigo em Inglês | MEDLINE | ID: mdl-34564613

RESUMO

Staphylococcal enterotoxin A (SEA), which is a superantigen toxin protein, binds to cytokine receptor gp130. Gp130 activates intracellular signaling pathways, including the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway. The effects of SEA on the JAK/STAT signaling pathway in mouse spleen cells were examined. After treatment with SEA, mRNA expression levels of interferon gamma (IFN-γ) and suppressor of cytokine-signaling 1 (SOCS1) increased. SEA-induced IFN-γ and SOCS1 expression were decreased by treatment with (-)-epigallocatechin gallate (EGCG). The phosphorylated STAT3, Tyr705, increased significantly in a SEA concentration-dependent manner in mouse spleen cells. Although (-)-3″-Me-EGCG did not inhibit SEA-induced phosphorylated STAT3, EGCG and (-)-4″-Me-EGCG significantly inhibited SEA-induced phosphorylated STAT3. It was thought that the hydroxyl group at position 3 of the galloyl group in the EGCG was responsible for binding to SEA and suppressing SEA-induced phosphorylation of STAT3. Through protein thermal shift assay in vitro, the binding of the gp130 receptor to SEA and the phosphorylation of STAT3 were inhibited by the interaction between EGCG and SEA. As far as we know, this is the first report to document that EGCG inhibits the binding of the gp130 receptor to SEA and the associated phosphorylation of STAT3.


Assuntos
Catequina/análogos & derivados , Catequina/metabolismo , Enterotoxinas/química , Enterotoxinas/metabolismo , Enterotoxinas/toxicidade , Janus Quinases/metabolismo , Fator de Transcrição STAT3/metabolismo , Animais , Células Cultivadas/efeitos dos fármacos , Modelos Animais de Doenças , Regulação Bacteriana da Expressão Gênica , Humanos , Camundongos , Transdução de Sinais/efeitos dos fármacos , Baço/efeitos dos fármacos , Staphylococcus aureus/química , Staphylococcus aureus/genética
17.
Toxins (Basel) ; 13(6)2021 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-34204819

RESUMO

Heat-labile toxin I (LT-I), produced by strains of enterotoxigenic Escherichia coli (ETEC), causes profuse watery diarrhea in humans. Different in vitro and in vivo models have already elucidated the mechanism of action of this toxin; however, their use does not always allow for more specific studies on how the LT-I toxin acts in systemic tracts and intestinal cell lines. In the present work, zebrafish (Danio rerio) and human intestinal cells (Caco-2) were used as models to study the toxin LT-I. Caco-2 cells were used, in the 62nd passage, at different cell concentrations. LT-I was conjugated to FITC to visualize its transport in cells, as well as microinjected into the caudal vein of zebrafish larvae, in order to investigate its effects on survival, systemic traffic, and morphological formation. The internalization of LT-I was visualized in 3 × 104 Caco-2 cells, being associated with the cell membrane and nucleus. The systemic traffic of LT-I in zebrafish larvae showed its presence in the cardiac cavity, yolk, and regions of the intestine, as demonstrated by cardiac edema (100%), the absence of a swimming bladder (100%), and yolk edema (80%), in addition to growth limitation in the larvae, compared to the control group. There was a reduction in heart rate during the assessment of larval survival kinetics, demonstrating the cardiotoxic effect of LT-I. Thus, in this study, we provide essential new depictions of the features of LT-I.


Assuntos
Toxinas Bacterianas/toxicidade , Escherichia coli Enterotoxigênica , Enterotoxinas/toxicidade , Proteínas de Escherichia coli/toxicidade , Animais , Toxinas Bacterianas/farmacocinética , Células CACO-2 , Edema/induzido quimicamente , Embrião não Mamífero/anormalidades , Embrião não Mamífero/efeitos dos fármacos , Embrião não Mamífero/metabolismo , Enterotoxinas/farmacocinética , Proteínas de Escherichia coli/farmacocinética , Cardiopatias Congênitas/induzido quimicamente , Frequência Cardíaca/efeitos dos fármacos , Humanos , Intestinos/metabolismo , Miocárdio/metabolismo , Saco Vitelino/efeitos dos fármacos , Peixe-Zebra/anormalidades , Peixe-Zebra/metabolismo
18.
Vet Res ; 52(1): 94, 2021 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-34174960

RESUMO

Small intestinal organoids, or enteroids, represent a valuable model to study host-pathogen interactions at the intestinal epithelial surface. Much research has been done on murine and human enteroids, however only a handful studies evaluated the development of enteroids in other species. Porcine enteroid cultures have been described, but little is known about their functional responses to specific pathogens or their associated virulence factors. Here, we report that porcine enteroids respond in a similar manner as in vivo gut tissues to enterotoxins derived from enterotoxigenic Escherichia coli, an enteric pathogen causing postweaning diarrhoea in piglets. Upon enterotoxin stimulation, these enteroids not only display a dysregulated electrolyte and water balance as shown by their swelling, but also secrete inflammation markers. Porcine enteroids grown as a 2D-monolayer supported the adhesion of an F4+ ETEC strain. Hence, these enteroids closely mimic in vivo intestinal epithelial responses to gut pathogens and are a promising model to study host-pathogen interactions in the pig gut. Insights obtained with this model might accelerate the design of veterinary therapeutics aimed at improving gut health.


Assuntos
Escherichia coli Enterotoxigênica/fisiologia , Enterotoxinas/toxicidade , Infecções por Escherichia coli/veterinária , Intestino Delgado/fisiopatologia , Organoides/fisiopatologia , Doenças dos Suínos/fisiopatologia , Animais , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/fisiopatologia , Interações Hospedeiro-Patógeno , Intestino Delgado/microbiologia , Organoides/microbiologia , Sus scrofa , Suínos , Doenças dos Suínos/microbiologia
19.
Proc Natl Acad Sci U S A ; 118(15)2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33876770

RESUMO

The bacterium Clostridium perfringens causes severe, sometimes lethal gastrointestinal disorders in humans, including enteritis and enterotoxemia. Type F strains produce an enterotoxin (CpE) that causes the third most common foodborne illness in the United States. CpE induces gut breakdown by disrupting barriers at cell-cell contacts called tight junctions (TJs), which are formed and maintained by claudins. Targeted binding of CpE to specific claudins, encoded by its C-terminal domain (cCpE), loosens TJ barriers to trigger molecular leaks between cells. Cytotoxicity results from claudin-bound CpE complexes forming pores in cell membranes. In mammalian tissues, ∼24 claudins govern TJ barriers-but the basis for CpE's selective targeting of claudins in the gut was undetermined. We report the structure of human claudin-4 in complex with cCpE, which reveals that enterotoxin targets a motif conserved in receptive claudins and how the motif imparts high-affinity CpE binding to these but not other subtypes. The structural basis of CpE targeting is supported by binding affinities, kinetics, and half-lives of claudin-enterotoxin complexes and by the cytotoxic effects of CpE on claudin-expressing cells. By correlating the binding residence times of claudin-CpE complexes we determined to claudin expression patterns in the gut, we uncover that the primary CpE receptors differ in mice and humans due to sequence changes in the target motif. These findings provide the molecular and structural element CpE employs for subtype-specific targeting of claudins during pathogenicity of C. perfringens in the gut and a framework for new strategies to treat CpE-based illnesses in domesticated mammals and humans.


Assuntos
Claudina-4/química , Enterotoxinas/química , Junções Íntimas/efeitos dos fármacos , Animais , Sítios de Ligação , Claudina-4/metabolismo , Clostridium perfringens , Enterotoxinas/toxicidade , Humanos , Simulação de Acoplamento Molecular , Ligação Proteica , Células Sf9 , Spodoptera , Junções Íntimas/metabolismo
20.
J Invest Dermatol ; 141(10): 2449-2458, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-33862068

RESUMO

Staphylococcal enterotoxins are believed to fuel disease activity in cutaneous T-cell lymphoma. Recent data support this by showing that antibiotics inhibit malignant T cells in skin lesions in mycosis fungoides and Sézary syndrome, the most common forms of cutaneous T-cell lymphoma. Yet, it remains incompletely characterized how staphylococcal enterotoxins fuel disease activity. In this study, we show that staphylococcal enterotoxins induce the expression of the oncogenic microRNA miR-155 in primary malignant T cells. Thus, staphylococcal enterotoxins and Staphyloccocus aureus isolates from lesional skin of patients induce miR-155 expression at least partly through the IL-2Rg‒Jak‒signal transducer and activator of transcription 5 pathway, and the effect is augmented by the presence of nonmalignant T cells. Importantly, mycosis fungoides lesions harbor S. aureus, express Y-phosphorylated signal transducer and activator of transcription 5, and display enhanced miR-155 expression, when compared with nonlesional and healthy skin. Preliminary data show that aggressive antibiotic therapy is associated with decreased Y-phosphorylated signal transducer and activator of transcription 5 and miR-155 expression in lesional skin in two patients with Sézary syndrome. In conclusion, we show that S. aureus and its enterotoxins induce enhanced expression of oncogenic miR-155, providing mechanistic insight into the role of S. aureus in cutaneous T-cell lymphoma. Our findings support that environmental stimuli such as bacteria can fuel disease progression in cutaneous T-cell lymphoma.


Assuntos
Enterotoxinas/toxicidade , Linfoma Cutâneo de Células T/etiologia , MicroRNAs/fisiologia , Fator de Transcrição STAT5/fisiologia , Neoplasias Cutâneas/etiologia , Staphylococcus aureus/patogenicidade , Antibacterianos/farmacologia , Linhagem Celular Tumoral , Humanos
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