UNLABELLED: We investigated the tripartite interactions between two intracellular bacterial symbionts, Cardinium and Wolbachia in Tyrophagus putrescentiae. Cultures of Tyrophagus putrescentiae are typically single-infected by one intracellular symbiont. However, co-infection can be experimentally induced by mixing single-infected cultures, resulting in 10% of mite individuals being double-infected (Cardinium + Wolbachia) and a corresponding reduction in host fitness. Here, we assembled the genomes of Cardinium and Wolbachia and analyzed their gene expression in parental single-infected and mixed mite cultures using population-level samples (ranging from 7,500 to 10,000 mites). Wolbachia interacts more extensively with its mite host than Cardinium in single-infected cultures. However, in mixed cultures, (i) Wolbachia exhibited reduced regulation of the host compared with Cardinium; (ii) the gene expression profile of Cardinium shifted, increasing its interactions with the host, whereas the gene expression profile of Wolbachia remained unchanged; and (iii) Wolbachia genes exhibited a loss of interactions with mite gene expression, as indicated by reduced correlations (for example with host MAPK, endocytosis, and calcium signaling pathways). The experiments show that at the mite population level, symbiont infection disrupts gene expression interaction between the two symbionts and their host in different ways. Wolbachia was more influenced by Cardinium gene expression than vice versa. Cardinium can inhibit the growth of Wolbachia by disrupting its interaction with the host, leading to a loss of Wolbachia's influence on mite immune and regulatory pathways. The reasons for responses are due to co-infection or the reduced frequency of Wolbachia single-infected individuals due to the analyses of population-level samples. IMPORTANCE: We found that Cardinium disrupts the interaction between Wolbachia and mite host. In Wolbachia single-infected cultures, strong correlations exist between symbiont and host gene expressions. Interestingly, although Cardinium can also interact with the host, this interaction appears weaker compared with Wolbachia in single-infected cultures. These results suggest that both symbionts affect mite host gene expression, particularly in immune and regulatory pathways. In mixed samples, Cardinium appears to outcompete Wolbachia by disrupting its host interaction. It indicates competition between these two intracellular symbionts in mite populations. Wolbachia belongs to a mite-specific supergroup Q, distinct from the more commonly studied Wolbachia supergroups. As these mite-specific bacteria exhibit pathogen-blocking effects, our findings may have relevance for other systems, such as ticks and tick-borne diseases. The study sheds light on intracellular symbiont interaction within a novel mite-symbiont model.
- MeSH
- Bacteroidetes * physiology genetics MeSH
- Mites * microbiology MeSH
- Symbiosis MeSH
- Wolbachia * genetics physiology MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
The parasitic protozoan Entamoeba histolytica secretes extracellular vesicles (EVs), but so far little is known about their function in the interaction with the host immune system. Infection with E. histolytica trophozoites can lead to formation of amebic liver abscesses (ALAs), in which pro-inflammatory immune responses of Ly6Chi monocytes contribute to liver damage. Men exhibit a more severe pathology as the result of higher monocyte recruitment and a stronger immune response. To investigate the role of EVs and pathogenicity in the host immune response, we studied the effect of EVs secreted by low pathogenic EhA1 and highly pathogenic EhB2 amebae on monocytes. Size and quantity of isolated EVs from both clones were similar. However, they differed in their proteome and miRNA cargo, providing insight into factors potentially involved in amebic pathogenicity. In addition, EVs were enriched in proteins with signaling peptides compared with the total protein content of trophozoites. Exposure to EVs from both clones induced monocyte activation and a pro-inflammatory immune response as evidenced by increased surface presentation of the activation marker CD38 and upregulated gene expression of key signaling pathways (including NF-κB, IL-17 and TNF signaling). The release of pro-inflammatory cytokines was increased in EV-stimulated monocytes and more so in male- than in female-derived cells. While EhA1 EV stimulation caused elevated myeloperoxidase (MPO) release by both monocytes and neutrophils, EhB2 EV stimulation did not, indicating the protective role of MPO during amebiasis. Collectively, our results suggest that parasite-released EVs contribute to the male-biased immunopathology mediated by pro-inflammatory monocytes during ALA formation.
- MeSH
- Liver Abscess, Amebic immunology parasitology MeSH
- Cytokines metabolism MeSH
- Entamoebiasis immunology parasitology MeSH
- Entamoeba histolytica * immunology pathogenicity genetics MeSH
- Extracellular Vesicles * immunology metabolism MeSH
- Humans MeSH
- Monocytes * immunology parasitology MeSH
- Signal Transduction * MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Hepatitis B virus (HBV) infection can cause liver disease and lead to hepatocellular carcinoma (HCC). To better understand the factors involved in viral infection and pathogenesis and to develop novel therapies, it is crucial to investigate virus-host interactions. HBV infection has been shown to increase the expression of the unconventional prefoldin RPB5 interactor (URI1), a cellular protein that promotes liver tumorigenesis and HCC metastasis. Our study investigated the role of URI1 in HBV infection in vitro. Although previous reports have suggested that URI1 may act as an HBV restriction factor, our results showed that URI1 silencing or overexpression did not affect HBV replication in HepG2-NTCP cells. In primary human hepatocytes, URI1 knockdown modestly reduced HBV markers but did not significantly alter acute infection. Supporting the premise that URI1 is a promising therapeutic target for HCC, our findings show that URI1 knockdown does not enhance HBV infection in an acute infection model. This suggests that URI1 may be a viable therapeutic target for patients with HBV-associated HCC without increasing HBV-related complications.
- MeSH
- Hep G2 Cells MeSH
- Gene Knockdown Techniques MeSH
- Hepatitis B * virology complications metabolism MeSH
- Carcinoma, Hepatocellular virology metabolism MeSH
- Hepatocytes * virology metabolism MeSH
- Host-Pathogen Interactions MeSH
- Humans MeSH
- Virus Replication * MeSH
- Hepatitis B virus * genetics physiology MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
The olfactory response of insect vectors such as phlebotomine sand flies is a key facet for investigating their interactions with vertebrate hosts and associated vector-borne pathogens. Such studies are mainly performed by assessing the electrophysiological response and the olfactory behaviour of these arthropods towards volatile organic compounds (VOCs) produced by hosts. Nonetheless, few studies are available for species of the subgenera Lutzomyia and Nyssomyia in South America, leaving a void for Old World sand fly species of the genus Phlebotomus. In this study, we evaluated the olfactory responses of Phlebotomus perniciosus, one of the most important vectors of Leishmania infantum in the Old World. To test the P. perniciosus behavioural response to VOCs, 28 compounds isolated from humans and dogs were assessed using electrophysiological (i.e., electroantennogram, EAG) and behavioural assays (i.e., Y-tube olfactometer). In the EAG trials, 14 compounds (i.e., acetic acid, nonanoic acid, 2-propanol, 2-butanol, pentanal, hexanal, nonanal, trans-2-nonenal, decanal, myrcene, p-cymene, verbenone, 2-ethyl-1-hexanol, and acetonitrile) elicited high antennal responses (i.e., ≥ 0.30 mV) in female sand flies, being those VOCs selected for the behavioural assays. From the 14 compounds tested in the Y-tube olfactometer, nonanal was significantly attractive for P. perniciosus females, whereas myrcene and p-cymene were significantly repellents (p < 0.05). The attraction indexes varied from 0.53 for nonanal (i.e., most attractive) to -0.47 to p-cymene (i.e., most repellent). Overall, our results shed light on the role of olfactory cues routing host seeking behaviour in P. perniciosus, with implications to develop sustainable sand fly monitoring as well as control in leishmaniasis endemic areas.
- MeSH
- Behavior, Animal drug effects MeSH
- Insect Vectors physiology drug effects MeSH
- Leishmania infantum drug effects physiology MeSH
- Humans MeSH
- Phlebotomus * physiology drug effects MeSH
- Dogs MeSH
- Volatile Organic Compounds * pharmacology chemistry analysis MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Dogs MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Mikroorganismy si během evoluce vyvinuly širokou škálu strategií, jak uniknout vrozenému i adaptivnímu imunitnímu systému, a některým těmto strategiím se věnujeme v našem přehledu. Mikroorganismy mohou využívat podobnost svých proteinů s proteiny hostitele, produkovat protizánětlivé faktory, narušovat komplementový systém, ovlivňovat funkci a blokovat syntézu cytokinů, inhibovat rozpoznávání imunoglobulinů, snižovat expresi a modifikovat antigeny na svém povrchu, narušovat zpracování a prezentaci antigenu imunitními buňkami, vstupovat do imunitních buněk, ovlivňovat apoptózu buněk, modulovat funkce imunitních buněk nebo ovlivňovat produkci hormonů. S těmito únikovými strategiemi je nutné počítat při léčbě infekčních onemocnění.
Microorganisms have evolved a wide variety of strategies to evade both the innate and adaptive immune systems during evolution, and some of these strategies are addressed in our review. Microorganisms can use the similarity of their proteins to host proteins, produce anti-inflammatory factors, disrupt the complement system, affect the function and block the synthesis of cytokines, inhibit the recognition of immunoglobulins, reduce the expression and modify antigens on their surface, disrupt the processing and presentation of antigen by immune cells, enter immune cells , influence cell apoptosis, modulate immune cell functions or influence hormone production. These escape strategies must be taken into account when treating infectious diseases.
- Keywords
- únikové strategie mikroorganismů,
- MeSH
- Host-Pathogen Interactions MeSH
- Humans MeSH
- Microbiological Phenomena * MeSH
- Immunity, Innate * MeSH
- Trained Immunity MeSH
- Check Tag
- Humans MeSH
- Publication type
- Review MeSH
Bordetella pertussis is the causative agent of whooping cough in humans, a disease that has recently experienced a resurgence. In contrast, Bordetella bronchiseptica infects the respiratory tract of various mammalian species, causing a range of symptoms from asymptomatic chronic carriage to acute illness. Both pathogens utilize type III secretion system (T3SS) to deliver the effector protein BteA into host cells. Once injected, BteA triggers a cascade of events leading to caspase 1-independent necrosis through a mechanism that remains incompletely understood. We demonstrate that BteA-induced cell death is characterized by the fragmentation of the cellular endoplasmic reticulum and mitochondria, the formation of necrotic balloon-like protrusions, and plasma membrane permeabilization. Importantly, genome-wide CRISPR-Cas9 screen targeting 19,050 genes failed to identify any host factors required for BteA cytotoxicity, suggesting that BteA does not require a single nonessential host factor for its cytotoxicity. We further reveal that BteA triggers a rapid and sustained influx of calcium ions, which is associated with organelle fragmentation and plasma membrane permeabilization. The sustained elevation of cytosolic Ca2+ levels results in mitochondrial calcium overload, mitochondrial swelling, cristolysis, and loss of mitochondrial membrane potential. Inhibition of calcium channels with 2-APB delays both the Ca2+ influx and BteA-induced cell death. Our findings indicate that BteA exploits essential host processes and/or redundant pathways to disrupt calcium homeostasis and mitochondrial function, ultimately leading to host cell death.IMPORTANCEThe respiratory pathogens Bordetella pertussis and Bordetella bronchiseptica exhibit cytotoxicity toward a variety of mammalian cells, which depends on the type III secretion effector BteA. Moreover, the increased virulence of B. bronchiseptica is associated with enhanced expression of T3SS and BteA. However, the molecular mechanism underlying BteA cytotoxicity is elusive. In this study, we performed a CRISPR-Cas9 screen, revealing that BteA-induced cell death depends on essential or redundant host processes. Additionally, we demonstrate that BteA disrupts calcium homeostasis, which leads to mitochondrial dysfunction and cell death. These findings contribute to closing the gap in our understanding of the signaling cascades targeted by BteA.
- MeSH
- Bacterial Proteins * metabolism genetics MeSH
- Bordetella bronchiseptica genetics metabolism drug effects MeSH
- Bordetella pertussis genetics pathogenicity metabolism drug effects MeSH
- Cell Death * drug effects MeSH
- Endoplasmic Reticulum metabolism drug effects MeSH
- Homeostasis * MeSH
- Host-Pathogen Interactions MeSH
- Humans MeSH
- Mitochondria metabolism drug effects MeSH
- Type III Secretion Systems metabolism genetics MeSH
- Calcium * metabolism MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
Neurotropic pathogens, notably, herpesviruses, have been associated with significant neuropsychiatric effects. As a group, these pathogens can exploit molecular mimicry mechanisms to manipulate the host central nervous system to their advantage. Here, we present a systematic computational approach that may ultimately be used to unravel protein-protein interactions and molecular mimicry processes that have not yet been solved experimentally. Toward this end, we validate this approach by replicating a set of pre-existing experimental findings that document the structural and functional similarities shared by the human cytomegalovirus-encoded UL144 glycoprotein and human tumor necrosis factor receptor superfamily member 14 (TNFRSF14). We began with a thorough exploration of the Homo sapiens protein database using the Basic Local Alignment Search Tool (BLASTx) to identify proteins sharing sequence homology with UL144. Subsequently, we used AlphaFold2 to predict the independent three-dimensional structures of UL144 and TNFRSF14. This was followed by a comprehensive structural comparison facilitated by Distance-Matrix Alignment and Foldseek. Finally, we used AlphaFold-multimer and PPIscreenML to elucidate potential protein complexes and confirm the predicted binding activities of both UL144 and TNFRSF14. We then used our in silico approach to replicate the experimental finding that revealed TNFRSF14 binding to both B- and T-lymphocyte attenuator (BTLA) and glycoprotein domain and UL144 binding to BTLA alone. This computational framework offers promise in identifying structural similarities and interactions between pathogen-encoded proteins and their host counterparts. This information will provide valuable insights into the cognitive mechanisms underlying the neuropsychiatric effects of viral infections.
- MeSH
- Cognition physiology MeSH
- Humans MeSH
- Molecular Mimicry * MeSH
- Models, Molecular MeSH
- Amino Acid Sequence MeSH
- Protein Binding MeSH
- Viral Proteins metabolism chemistry MeSH
- Computational Biology methods MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
BACKGROUND: Schistosoma mansoni was introduced from Africa to the Americas during the transatlantic slave trade and remains a major public health problem in parts of South America and the Caribbean. This study presents a comprehensive comparative analysis of three S. mansoni strains with different geographical origins-from Liberia, Belo Horizonte and Puerto Rico. We demonstrated significant variation in virulence and host-parasite interactions. METHODS: We investigated the phenotypic characteristics of the parasite and its eggs, as well as the immunopathologic effects on laboratory mouse organ systems. RESULTS: Our results show significant differences in worm morphology, worm burden, egg size, and pathologic organ changes between these strains. The Puerto Rican strain showed the highest virulence, as evidenced by marked liver and spleen changes and advanced liver fibrosis indicated by increased collagen content. In contrast, the strains from Liberia and Belo Horizonte had a less pathogenic profile with less liver fibrosis. We found further variations in granuloma formation, cytokine expression and T-cell dynamics, indicating different immune responses. CONCLUSION: Our study emphasizes the importance of considering intra-specific variations of S. mansoni for the development of targeted therapies and public health strategies. The different virulence patterns, host immune responses and organ pathologies observed in these strains provide important insights for future research and could inform region-specific interventions for schistosomiasis control.
- MeSH
- Cytokines metabolism MeSH
- Host-Parasite Interactions MeSH
- Liver * parasitology pathology MeSH
- Mice MeSH
- Schistosoma mansoni * pathogenicity genetics immunology MeSH
- Schistosomiasis mansoni * parasitology immunology pathology MeSH
- Spleen parasitology pathology immunology MeSH
- Virulence MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Liberia MeSH
- Puerto Rico MeSH
Trematodes of the order Diplostomida are well known as serious pathogens of man, and both farm and wild animals; members of the genus Schistosoma (Schistosomatidae) are responsible for human schistosomosis (schistosomiasis) affecting more than 200 million people in tropical and subtropical countries, and infections of mammals and birds by animal schistosomes are of great veterinary importance. The order Diplostomida is also rich in species parasitizing other major taxa of vertebrates. The "Aporocotylidae" sensu lato are pathogenic in fish, "Spirorchiidae" sensu lato in reptiles. All these flukes have two-host life cycles, with asexually reproducing larvae usually in mollusks and occasionally in annelids, and adults usually live in the blood vessels of their vertebrate hosts. Pathology is frequently associated with inflammatory reactions to eggs trapped in various tissues/organs. On the other hand, the representatives of Diplostomidae and Strigeidae have three- or four-host life cycles in which vertebrates often serve not only as definitive but also as intermediate or paratenic hosts. Pathology is usually associated with migration of metacercariae and mesocercariae within the host tissues. The impact of these trematode infections on both farm and wild animals may be significant.
Francisella is a highly infectious gram-negative bacterium that causes tularemia in humans and animals. It can survive and multiply in a variety of cells, including macrophages, dendritic cells, amoebae, and arthropod-derived cells. However, the intracellular life cycle of a bacterium varies depending on the cell type. Shortly after the infection of mammalian cells, the bacterium escapes the phagosome into the cytosol, where it replicates. In contrast, in the amoebae Acanthamoeba castellanii and Hartmannella vermiformis, the bacterium replicates within the membrane-bound vacuole. In recent years, the amoeba Dictyostelium discoideum has emerged as a powerful model to study the intracellular cycle and virulence of many pathogenic bacteria. In this study, we used D. discoideum as a model for the infection and isolation of Francisella novicida-containing vacuoles (FCVs) formed after bacteria invade the amoeba. Our results showed that F. novicida localized in a vacuole after invading D. discoideum. Here, we developed a method to isolate FCV and determined its composition by proteomic analyses. Proteomic analyses revealed 689 proteins, including 13 small GTPases of the Rab family. This is the first evidence of F. novicida-containing vacuoles within amoeba, and this approach will contribute to our understanding of host-pathogen interactions and the process of pathogen vacuole formation, as vacuoles containing bacteria represent direct contact between pathogens and their hosts. Furthermore, this method can be translocated on other amoeba models.
- Publication type
- Journal Article MeSH
