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The emergence of antimicrobial resistance has created an urgent need for alternative treatments against bacterial pathogens. Here, we investigated kinase inhibitors as potential host-directed therapies (HDTs) against intracellular bacteria, specifically Salmonella Typhimurium (Stm) and Mycobacterium tuberculosis (Mtb). We screened 827 ATP-competitive kinase inhibitors with known target profiles from two Published Kinase Inhibitor Sets (PKIS1 and PKIS2) using intracellular infection models for Stm and Mtb, based on human cell lines and primary macrophages. Additionally, the in vivo safety and efficacy of the compounds were assessed using zebrafish embryo infection models. Our screen identified 11 hit compounds for Stm and 17 hit compounds for Mtb that were effective against intracellular bacteria and non-toxic for host cells. Further experiments were conducted to prioritize Stm hit compounds that were able to clear the intracellular infection in primary human macrophages. From these, two structurally related Stm hit compounds, GSK1379738A and GSK1379760A, exhibited significant activity against Stm in infected zebrafish embryos. In addition, we identified compounds that were active against intracellular Mtb, including morpholino-imidazo/triazolo-pyrimidinones that target PIK3CB, as well as 2-aminobenzimidazoles targeting ABL1. Overall, this study provided insights into kinase targets acting at the host-pathogen interface and identified several kinase inhibitors as potential HDTs.
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Macrófagos , Mycobacterium tuberculosis , Inhibidores de Proteínas Quinasas , Salmonella typhimurium , Pez Cebra , Animales , Humanos , Salmonella typhimurium/efectos de los fármacos , Mycobacterium tuberculosis/efectos de los fármacos , Mycobacterium tuberculosis/enzimología , Inhibidores de Proteínas Quinasas/farmacología , Macrófagos/microbiología , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Infecciones por Salmonella/tratamiento farmacológico , Infecciones por Salmonella/microbiología , Antibacterianos/farmacología , Línea Celular , Embrión no Mamífero/efectos de los fármacos , Tuberculosis/tratamiento farmacológico , Tuberculosis/microbiologíaRESUMEN
Mycobacterium tuberculosis (Mtb) is the causative pathogen of tuberculosis, the most lethal infectious disease resulting in 1.3 million deaths annually. Treatments against Mtb are increasingly impaired by the growing prevalence of antimicrobial drug resistance, which necessitates the development of new antibiotics or alternative therapeutic approaches. Upon infecting host cells, predominantly macrophages, Mtb becomes critically dependent on lipids as a source of nutrients. Additionally, Mtb produces numerous lipid-based virulence factors that contribute to the pathogen's ability to interfere with the host's immune responses and to create a lipid rich environment for itself. As lipids, lipid metabolism and manipulating host lipid metabolism play an important role for the virulence of Mtb, this review provides a state-of-the-art overview of mycobacterial lipid metabolism and concomitant role of host metabolism and host-pathogen interaction therein. While doing so, we will emphasize unexploited bacteria-directed and host-directed drug targets, and highlight potential synergistic drug combinations that hold promise for the development of new therapeutic interventions.
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The increasing prevalence of antimicrobial-resistant Staphylococcus aureus strains, especially methicillin-resistant S. aureus (MRSA), poses a threat to successful antibiotic treatment. Unsuccessful attempts to develop a vaccine and rising resistance to last-resort antibiotics urge the need for alternative treatments. Host-directed therapy (HDT) targeting critical intracellular stages of S. aureus emerges as a promising alternative, potentially acting synergistically with antibiotics and reducing the risk of de novo drug resistance. We assessed 201 ATP-competitive kinase inhibitors from Published Kinase Inhibitor Sets (PKIS1 and PKIS2) against intracellular MRSA. Seventeen hit compounds were identified, of which the two most effective and well-tolerated hit compounds (i.e., GW633459A and GW296115X) were selected for further analysis. The compounds did not affect planktonic bacterial cultures, while they were active in a range of human cell lines of cervical, skin, lung, breast and monocyte origin, confirming their host-directed mechanisms. GW633459A, structurally related to lapatinib, exhibited an HDT effect on intracellular MRSA independently of its known human epidermal growth factor receptor (EGFR)/(HER) kinase family targets. GW296115X activated adenosine monophosphate-activated protein kinase (AMPK), thereby enhancing bacterial degradation via autophagy. Finally, GW296115X not only reduced MRSA growth in human cells but also improved the survival rates of MRSA-infected zebrafish embryos, highlighting its potential as HDT.
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Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Humanos , Animales , Staphylococcus aureus , Pez Cebra , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Infecciones Estafilocócicas/microbiología , Pruebas de Sensibilidad MicrobianaRESUMEN
INTRODUCTION: Before release, vaccine batches are assessed for quality to evaluate whether they meet the product specifications. Vaccine batch tests, in particular of inactivated and toxoid vaccines, still largely rely on in vivo methods. Improved vaccine production processes, ethical concerns, and suboptimal performance of some in vivo tests have led to the development of in vitro alternatives. AREAS COVERED: This review describes the scientific constraints that need to be overcome for replacement of in vivo batch tests, as well as potential solutions. Topics include the critical quality attributes of vaccines that require testing, the use of cell-based assays to mimic aspects of in vivo vaccine-induced immune responses, how difficulties with testing adjuvanted vaccines in vitro can be overcome, the use of altered batches to validate new in vitro test methods, and how cooperation between different stakeholders is key to moving the transition forward. EXPERT OPINION: For safety testing, many in vitro alternatives are already available or at an advanced level of development. For potency testing, in vitro alternatives largely comprise immunochemical methods that assess several, but not all critical vaccine properties. One-to-one replacement by in vitro alternatives is not always possible and a combination of methods may be required.
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Vacunas Bacterianas , Proyectos de Investigación , Humanos , Control de CalidadRESUMEN
Salmonella enterica serotype Enteritidis (SE) is a zoonotic pathogen which causes foodborne diseases in humans as well as severe disease symptoms in young chickens. More insight in innate and adaptive immune responses of chickens to SE infection is needed to understand elimination of SE. Seven-day-old broiler chickens were experimentally challenged with SE and numbers and responsiveness of innate and adaptive immune cells as well as antibody titers were assessed. SE was observed in the ileum and spleen of SE-infected chickens at 7 days post-infection (dpi). At 1 dpi numbers of intraepithelial cytotoxic CD8+ T cells were significantly increased alongside numerically increased intraepithelial IL-2Rα+ and 20E5+ natural killer (NK) cells at 1 and 3 dpi. At both time points, activation of intraepithelial and splenic NK cells was significantly enhanced. At 7 dpi in the spleen, presence of macrophages and expression of activation markers on dendritic cells were significantly increased. At 21 dpi, SE-induced proliferation of splenic CD4+ and CD8+ T cells was observed and SE-specific antibodies were detected in sera of all SE-infected chickens. In conclusion, SE results in enhanced numbers and activation of innate cells and we hypothesized that in concert with subsequent specific T cell and antibody responses, reduction of SE is achieved. A better understanding of innate and adaptive immune responses important in the elimination of SE will aid in developing immune-modulation strategies, which may increase resistance to SE in young broiler chickens.
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Inmunidad Adaptativa , Pollos , Inmunidad Innata , Enfermedades de las Aves de Corral/inmunología , Salmonelosis Animal/inmunología , Salmonella enteritidis/fisiología , Animales , Femenino , Masculino , Enfermedades de las Aves de Corral/microbiología , Salmonelosis Animal/microbiologíaRESUMEN
Inactivated poultry vaccines are subject to routine potency testing for batch release, requiring large numbers of animals. The replacement of in vivo tests for cell-based alternatives can be facilitated by the identification of biomarkers for vaccine-induced immune responses. In this study, chicken bone marrow-derived dendritic cells were stimulated with an inactivated vaccine for infectious bronchitis virus and Newcastle disease virus, as well as inactivated infectious bronchitis virus only, and lipopolysaccharides as positive control, or left unstimulated for comparison with the stimulated samples. Next, the cells were lysed and subjected to proteomic analysis. Stimulation with the vaccine resulted in 66 differentially expressed proteins associated with mRNA translation, immune responses, lipid metabolism and the proteasome. For the eight most significantly upregulated proteins, mRNA expression levels were assessed. Markers that showed increased expression at both mRNA and protein levels included PLIN2 and PSMB1. Stimulation with infectious bronchitis virus only resulted in 25 differentially expressed proteins, which were mostly proteins containing Src homology 2 domains. Stimulation with lipopolysaccharides resulted in 118 differentially expressed proteins associated with dendritic cell maturation and antimicrobial activity. This study provides leads to a better understanding of the activation of dendritic cells by an inactivated poultry vaccine, and identified PLIN2 and PSMB1 as potential biomarkers for cell-based potency testing.
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Células Dendríticas , Marcadores Genéticos/inmunología , Aves de Corral/inmunología , Vacunas Virales , Animales , Células de la Médula Ósea/efectos de los fármacos , Células de la Médula Ósea/metabolismo , Células Cultivadas/efectos de los fármacos , Células Cultivadas/metabolismo , Pollos , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Expresión Génica/inmunología , Inmunidad Innata , Virus de la Bronquitis Infecciosa/inmunología , Enfermedad de Newcastle/inmunología , Enfermedad de Newcastle/prevención & control , Perilipina-2/inmunología , Perilipina-2/metabolismo , Aves de Corral/genética , Enfermedades de las Aves de Corral/inmunología , Enfermedades de las Aves de Corral/prevención & control , Enfermedades de las Aves de Corral/virología , Complejo de la Endopetidasa Proteasomal/inmunología , Complejo de la Endopetidasa Proteasomal/metabolismo , Proteómica , Vacunas de Productos Inactivados/inmunología , Vacunas de Productos Inactivados/farmacología , Vacunas Virales/inmunología , Vacunas Virales/farmacologíaRESUMEN
Recently, we have reported trained innate immunity in laying chicken monocytes. In the present study, we further investigated trained innate immunity of monocytes in layers and broilers. Monocytes of both breeds isolated from blood were trained in vitro with ß-glucan, rec-chicken IL-4 or a combination of both, and restimulated with lipopolysaccharide (LPS), after which inflammation and metabolism-related responses were measured. Training of laying and broiler hen monocytes resulted in increased mRNA levels of IL-1ß, iNOS and HIF-1α, but enhanced surface expression of CD40 and NO production was only observed in layers. Our in vitro study demonstrates that monocytes from different genetic backgrounds can be trained. However, the observed differences suggest a differential effect on immune functionality associated with innate training. Whether these differences in immune functions between layers and broilers have effect on disease resistance remains to be elucidated.
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Pollos/inmunología , Monocitos/metabolismo , Animales , Antígenos CD40/metabolismo , Células Cultivadas , Reprogramación Celular , Regulación de la Expresión Génica , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Inmunidad Innata , Interleucina-1beta/metabolismo , Interleucina-4/inmunología , Lipopolisacáridos/inmunología , Monocitos/inmunología , Óxido Nítrico , Óxido Nítrico Sintasa de Tipo II/metabolismo , beta-Glucanos/inmunologíaRESUMEN
High-quality vaccines are crucial to prevent infectious disease outbreaks in the poultry industry. In vivo vaccination tests are routinely used to test poultry vaccines for their potency, i.e., their capacity to induce protection against the targeted diseases. A better understanding of how poultry vaccines activate immune cells will facilitate the replacement of in vivo potency tests for in vitro assays. Using the chicken macrophage-like HD11 cell line as a model to evaluate innate immune responses, the current explorative study addresses the immunostimulatory capacity of an inactivated multivalent vaccine for infectious bronchitis, Newcastle disease, egg-drop syndrome, and infectious coryza. The vaccine stimulated HD11 cells to produce nitric oxide and to express pro-inflammatory cytokines IL-1ß, TNF, and IL-12p40, chemokines CXCLi1 and CXCLi2, and the anti-inflammatory cytokine IL-10, but only when inactivated Avibacterium paragallinarum, the causative agent of infectious coryza, was present. Lipopolysaccharides from Avibacterium paragallinarum were crucial for the production of nitric oxide and expression of IL-1ß and CXCLi1. The described immune parameters demonstrate the capacity of this multivalent vaccine to activate innate immune cells and may in the future, combined with antigen quantification methods, contribute to vaccine quality testing in vitro, hence the replacement of current in vivo vaccination tests.
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Macrophages are part of the first line of defense against invading pathogens. In mammals, the in vitro culture of macrophages from blood monocytes or bone marrow cells is well established, including culturing conditions to differentiate them towards M1 or M2-like macrophages. In chicken, monocyte-derived macrophages have been used in several studies, but there is no uniform protocol or actual characterization of these cells. Therefore, to generate proinflammatory M1-like macrophages, in this study blood monocytes were differentiated using GM-CSF for 4 days and characterized based on cell morphology, surface marker expression and cytokine expression response to TLRs stimulation at each (daily) time point. Cell morphology showed that one-day-cultured cells contained a mixture of cell populations, while the homogenous population of cells on day 3 and day 4 were flat and had a 'fried-egg' like shape, similar to human M1 macrophages. In addition, cell surface marker staining showed that 3 and 4- days-cultured cells expressed a high level of MRC1L-B (KUL01) and MHC-II. Furthermore, LPS stimulation of the cultured cells induced gene expression of the proinflammatory cytokines IL-1ß, IL-6 and IL-8 after 3 days of culture. Finally, it was shown that day 3 macrophages were able to phagocytose avian pathogenic E. coli (APEC) and respond by nitric oxide production. Overall, our systematic characterization of the monocyte derived cells from blood showed that a 3-days culture was optimal to obtain pro-inflammatory M1 like macrophages, increasing our knowledge about chicken macrophage polarization and providing useful information for studies on chicken macrophage phenotypes.
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Citocinas/metabolismo , Mediadores de Inflamación/metabolismo , Macrófagos/inmunología , Macrófagos/metabolismo , Monocitos/inmunología , Monocitos/metabolismo , Animales , Biomarcadores , Diferenciación Celular/inmunología , Plasticidad de la Célula/inmunología , Células Cultivadas , Pollos , Activación de Macrófagos/inmunología , Macrófagos/citología , Monocitos/citologíaRESUMEN
Beta-glucan-stimulated mammalian myeloid cells, such as macrophages, show an increased responsiveness to secondary stimulation in a nonspecific manner. This phenomenon is known as trained innate immunity and is important to prevent reinfections. Trained innate immunity seems to be an evolutionary conserved phenomenon among plants, invertebrates and mammalian species. Our study aimed to explore the training of primary chicken monocytes. We hypothesized that primary chicken monocytes, similar to their mammalian counterparts, can be trained with ß-glucan resulting in increased responses of these cells to a secondary stimulus. Primary blood monocytes of white leghorn chickens were primary stimulated with ß-glucan microparticulates (M-ßG), lipopolysaccharide (LPS), recombinant chicken interleukin-4 (IL-4) or combinations of these components for 48 h. On day 6, the primary stimulated cells were secondary stimulated with LPS. Nitric oxide (NO) production levels were measured as an indicator of pro-inflammatory activity. In addition, the cells were analyzed by flow cytometry to characterize the population of trained cells and to investigate the expression of surface markers associated with activation. After the secondary LPS stimulation, surface expression of colony stimulating factor 1 receptor (CSF1R) and the activation markers CD40 and major histocompatibility complex class II (MHC-II) was higher on macrophages that were trained with a combination of M-ßG and IL-4 compared to unstimulated cells. This increased expression was paralleled by enhanced NO production. In conclusion, this study showed that trained innate immunity can be induced in primary chicken monocytes with ß-glucan, which is in line with previous experiments in mammalian species. Innate immune training may have the potential to improve health and vaccination strategies within the poultry sector.
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Research in chickens has been fundamental for the discovery of basic aspects of the immune system and has led to an interest in the in-depth characterization of avian immune cell types including dendritic cells (DCs). The in vitro generation and expansion of chicken bone marrow-derived DCs (chBMDCs) in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) has provided a way to study chicken DCs, which are only present at limited cell numbers in vivo. This method has been employed to study the interactions between chicken DCs and pathogens or vaccines. However, a detailed characterization of the chBMDC culture is still lacking. In the present study, we performed an elaborate phenotypical and functional analysis of the chBMDC culture and addressed its heterogeneity. After 8 days of culture, chBMDCs comprised major histocompatibility complex class II (MHC-II)low and MHC-IIhigh subsets with different morphologies. Compared with MHC-IIlow chBMDCs, the MHC-IIhigh subset showed a more mature phenotype, with higher expressions of CD1.1, CD40, CD80, CCR7, and CD83, and a relatively low opsonophagocytic capacity. Nevertheless, MHC-IIhigh chBMDCs did not show an increased capacity to induce T-cell proliferation. Therefore, MHC-IIhigh chBMDCs were found to be semi-mature. Interestingly, the presence of the semi-mature MHC-IIhigh chBMDC subset reduced when cells were cultured in the presence of IL-4. Finally, prolonged cell culture after fluorescence-activated cell sorting (FACS) converted the semi-mature MHC-IIhigh subset back into the immature phenotype of the MHC-IIlow subset, demonstrating plasticity of their maturation state. This detailed characterization explained the heterogeneity of the chBMDC culture by the simultaneous presence of immature and semi-mature chBMDC subsets, in addition to cells without features of antigen-presenting cells. Our findings are instrumental for the interpretation of experiments using the chBMDC culture in past and future research by providing insights into its phenotypically and functionally distinct cell types.
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Células de la Médula Ósea/citología , Diferenciación Celular/inmunología , Pollos/inmunología , Células Dendríticas/citología , Células Dendríticas/inmunología , Animales , Diferenciación Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Embrión de Pollo , Células Dendríticas/metabolismo , Citometría de Flujo , Expresión Génica/efectos de los fármacos , Factor Estimulante de Colonias de Granulocitos y Macrófagos/metabolismo , Antígenos de Histocompatibilidad Clase II/metabolismo , Interleucina-4/farmacología , Lipopolisacáridos/farmacología , Fagocitosis/efectos de los fármacos , Fagocitosis/inmunología , Fenotipo , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/farmacología , Transducción de Señal/efectos de los fármacosRESUMEN
Mucosa-associated invariant T (MAIT) cells are unconventional innate-like T cells that recognize microbial riboflavin metabolites presented by the MHC class I-like protein MR1. Human MAIT cells predominantly express the CD8α coreceptor (CD8+), with a smaller subset lacking both CD4 and CD8 (double-negative, DN). However, it is unclear if these two MAIT cell subpopulations distinguished by CD8α represent functionally distinct subsets. Here, we show that the two MAIT cell subsets express divergent transcriptional programs and distinct patterns of classic T cell transcription factors. Furthermore, CD8+ MAIT cells have higher levels of receptors for IL-12 and IL-18, as well as of the activating receptors CD2, CD9, and NKG2D, and display superior functionality following stimulation with riboflavin-autotrophic as well as riboflavin-auxotrophic bacterial strains. DN MAIT cells display higher RORγt/T-bet ratio, and express less IFN-γ and more IL-17. Furthermore, the DN subset displays enrichment of an apoptosis gene signature and higher propensity for activation-induced apoptosis. During development in human fetal tissues, DN MAIT cells are more mature and accumulate over gestational time with reciprocal contraction of the CD8+ subset. Analysis of the T cell receptor repertoire reveals higher diversity in CD8+ MAIT cells than in DN MAIT cells. Finally, chronic T cell receptor stimulation of CD8+ MAIT cells in an in vitro culture system supports the accumulation and maintenance of the DN subpopulation. These findings define human CD8+ and DN MAIT cells as functionally distinct subsets and indicate a derivative developmental relationship.