Os autores agradecem a K. Kissa para discussões úteis e para a prestação de lipo-clodronate e L. Ramakrishnan pelo dom generoso de pTEC27 e pTEC15 que permitir a expressão de tdTomato e Wasabi, respectivamente. Este trabalho faz parte dos projetos da Agência Nacional de Investigação francesa (ZebraFlam ANR-10 MIDI-009 e DIMYVIR ANR-13-BSV3-007-01) e Sétimo Programa-Quadro da Comunidade Europeia (FP7-PEOPLE-2011-ITN) sob acordo de subvenção não. PITN-GA-2011-289209 para a Marie-Curie de Formação Inicial Rede FishForPharma. Gostaríamos também de agradecer à Associação Gregory Lemarchal e Vaincre La mucoviscidose (RF20130500835) para o financiamento CM Dupont.

The authors have nothing to disclose.

O peixe-zebra emergiu recentemente como um excelente sistema modelo para o estudo dos vertebrados dinâmica da infecção bacteriana usando um campo largo e de imagem confocal em tempo real 36. A combinação de suspensões de micobactérias dispersas (protocolo 2.2), juntamente com métodos micro-injecção (protocolo 4) permite infecções sistêmicas, reprodutíveis e posterior acompanhamento e visualização da progressão da infecção com um foco especial sobre as interações bacterianas com macrófago...

Mycobacterium abscessus é um agente patogénico emergente que faz com que um largo espectro de síndromes clínicos em seres humanos. Estes incluem infecções cutâneas, bem como infecções pulmonares crônicas graves, principalmente encontrados em imunocomprometidos e em pacientes com fibrose cística 1,2,3,4. M. abscessus também é considerado como um dos principais rápido crescimento espécies de micobactérias responsáveis ​​por infecções hospitalares e iatrogênica em seres humanos. Além disso, vários relatórios recentes em destaque a possibilidade de que M. abscessus pode atravessar a barreira sangue-cérebro e induzir lesões importantes no sistema nervoso central (SNC) 5,6. Apesar de ser um cultivador rápido, M. exposições abscessus também várias características patogênicas que estão relacionados com os do Mycobacterium tuberculosis, incluindo a capacidade de permanecer em silêncio durante anos dentro de estruturas granulomatosas e gerar lesões caseosas nos pulmões 7. Mais alarmante é a baixa sensensibili- de M. abscessus aos antibióticos, tornando estas infecções extremamente difícil de tratar levando a uma taxa de insucesso terapêutico significativo 8,9. A ameaça importante desta espécie é principalmente a sua resistência intrínseca a antibióticos, que é de grande preocupação em instituições de saúde públicas 10 e uma contra-indicação para transplante pulmonar 11. M. abscessus exibe lisas (S) ou ásperas morfotipos (R) da colônia que levam a desfechos clínicos diferentes. Em contraste com a estirpe S, R bactérias têm uma tendência para crescer uma extremidade à outra, levando a uma corda ou cabo, como a estrutura 12,13. Vários estudos independentes com base em modelos celulares e animais seja revelado o fenótipo hiper-virulência do morfotipo R 14,15. A partir de estudos epidemiológicos, os casos mais graves de M. infecções pulmonares abscessus parecem estar associados com R 16 variantes que são a única variante quetem sido visto a persistir por anos em um hospedeiro infectado 3. A diferença morfotipo depende da presença (em S) ou perda (em R $) de glycopeptidolipids associada de superfície (GPL) 12. No entanto, devido às limitações inerentes dos modelos celulares / animais actualmente disponíveis utilizados para estudar M. infecção abscessus, o nosso conhecimento sobre os eventos fisiopatológicos das variantes R ou S permanece obscura. A infecção de ratos imuno-competentes através de via intravenosa ou aerossóis conduz à colonização transiente, o que dificulta a utilização de ratos para estudar infecções persistentes e in vivo para os testes de susceptibilidade droga 17. Por conseguinte, o desenvolvimento de modelos animais susceptíveis à manipulação da resposta do hospedeiro é um grande desafio. Neste contexto, os modelos não-mamíferos de infecção foram recentemente desenvolvidos, incluindo Drosophila melanogaster 18 que oferece várias vantagens, tais como custos, velocidade e ética o aceitabilidadeVer o modelo de mouse. O modelo de peixe-zebra (Danio rerio) de infecção também tem sido explorada para visualizar, por imagem não-invasivo, a progressão e cronologia da M. abscessus infecção em um animal vivo 19. Importante, uma prova de conceito também foi criado para demonstrar a sua aptidão para avaliações in vivo de antibióticos contra M. abscessus 17,20. O peixe-zebra têm sido amplamente utilizados durante as duas últimas décadas para estudar as interacções entre vários agentes patogénicos e o sistema imune do hospedeiro 21. O crescente sucesso deste modelo vertebrado alternativa depende de grandes e únicas oportunidades que motivaram e validados a sua utilização para uma melhor compreensão das inúmeras infecções virais e bacterianas 19,22,23,24,25,26,27,28,29. Ao contrário da maioria dos outros modelos animais, embriões de peixe-zebra são opticamente transparentes, permitindo que imagens de fluorescência não-invasivo 30. Esta has levou a estudar M. abscessus infectado embriões de peixe-zebra com detalhes sem precedentes, culminando com a descrição dos cordões extracelular, que representam um exemplo de plasticidade morfológica bacteriana. Cordões representa um novo mecanismo de subverter o sistema imunitário e um mecanismo de chave promover patogénese de M. aguda infecção abscessus 19. Este relatório descreve novas ferramentas e métodos que utilizam o embrião de peixe-zebra para decifrar os traços fisiopatológicos da M. abscessus infecção e para estudar as interacções entre os bacilos íntimas e do sistema imune inato. Em primeiro lugar, um protocolo detalhado microinjecção que inclui o processamento do inoculo bacteriano, preparação de embriões, e infecção por si só, é apresentada. Métodos especificamente adaptado para avaliar M. virulência abscessus medindo vários parâmetros, tais como a sobrevivência do hospedeiro e a carga bacteriana, são apresentados. É dado especial relevo sobre comopara monitorar, a um nível de espaço-temporal, o destino e a progressão da infecção e da resposta imune do hospedeiro a M. abscessus usando microscopia de vídeo. Além disso, para investigar a contribuição eo papel dos macrófagos durante M. abscessus infecção, métodos para gerar macrófagos-empobrecido embriões (usando abordagens quer genetically- ou baseados em quimicamente) são descritos. Finalmente, os protocolos para visualizar as interações específicas com macrófagos ou neutrófilos seja utilizando embriões fixos ou vivem são documentados. O objetivo deste relatório é estimular novos estudos para lançar uma nova luz em M. mecanismos de virulência abscessus e particularmente o papel de cordões no estabelecimento de um processo de infecção aguda e descontrolada.

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deciphering and imaging pathogenesis and cording of mycobacterium abscessus in zebrafish embryos

Zebrafish (Danio rerio) embryos are increasingly used as an infection model to study the function of the vertebrate innate immune system in host-pathogen interactions.&#160;The ease of obtaining large numbers of embryos, their accessibility due to external development, their optical transparency as well as the availability of a wide panoply of genetic/immunological tools and transgenic reporter line collections, contribute to the versatility of this model.&#160;In this respect, the present manuscript describes the use of zebrafish as an&#160;in vivo&#160;model system to investigate the chronology of Mycobacterium abscessus infection. This human pathogen can exist either as smooth (S) or rough (R) variants, depending on cell wall composition, and their respective virulence can be imaged and compared in zebrafish embryos and larvae. Micro-injection of either S or R fluorescent variants directly in the blood circulation via the caudal vein, leads to chronic or acute/lethal infections, respectively. This biological system allows high resolution visualization and analysis of the role of mycobacterial cording in promoting abscess formation. In addition, the use of fluorescent bacteria along with transgenic zebrafish lines harbouring fluorescent macrophages produces a unique opportunity for multi-color imaging of the host-pathogen interactions. This article describes detailed protocols for the preparation of homogenous M. abscessus inoculum and for intravenous injection of zebrafish embryos for subsequent fluorescence imaging of the interaction with macrophages. These techniques open the avenue to future investigations involving mutants defective in cord formation and are dedicated to understand how this impacts on M. abscessus pathogenicity in a whole vertebrate.

Apesar de vários sítios anatômicos podem ser injetados 32, injeções veia caudal são muitas vezes utilizados para gerar infecção sistêmica para análises posteriores, incluindo experiências de sobrevivência, determinação carga bacteriana, atividade fagocitose ou a formação do cordão umbilical. As injecções nos músculos da cauda são usados ​​para avaliar o recrutamento de macrófagos no local da injecção (Figura 3A). Para investigar e comparar a virulência de R e S va...

Watch this Scientific Journal Video about Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos at JoVE.com

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos

Optically transparent zebrafish embryos are widely used to study and visualize in real time the interactions between pathogenic microorganisms and the innate immune cells. Micro-injection of Mycobacterium abscessus, combined with fluorescence imaging, is used to scrutinize essential pathogenic features such as cord formation in zebrafish embryos.

Decifrar e Imagem Patogênese e Cording de<em&gt; Mycobacterium abscessus</em&gt; Em embriões Zebrafish

Zebrafish (Danio rerio) embryos are increasingly used as an infection model to study the function of the vertebrate innate immune system in host-pathogen ...

deciphering-imaging-pathogenesis-cording-mycobacterium-abscessus

Research

JoVE Journal

Immunology and Infection

Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos

10.1K visualizações.  Université Montpellier. Optically transparent zebrafish embryos are widely used to study and visualize in real time the interactions between pathogenic microorganisms and the innate immune cells. Micro-injection of Mycobacterium abscessus, combined with fluorescence imaging, is used to scrutinize essential pathogenic features such as cord formation in zebrafish embryos. 

Vídeo: Deciphering and Imaging Pathogenesis and Cording of Mycobacterium abscessus in Zebrafish Embryos

Imaging of HIV-1 Envelope-induced Virological Synapse and Signaling on Synthetic Lipid Bilayers

Human immunodeficiency virus type 1 (HIV-1) infection occurs most efficiently via cell to cell transmission2,10,11. This cell to cell transfer between CD4+ T cells involves the formation of a virological synapse (VS), which is an F-actin-dependent cell-cell junction formed upon the engagement of HIV-1 envelope gp120 on the infected cell with CD4 and the chemokine receptor (CKR) CCR5 or CXCR4 on the target cell 8. In addition to gp120 and its receptors, other membrane proteins, particularly the adhesion molecule LFA-1 and its ligands, the ICAM family, play a major role in VS formation and virus transmission as they are present on the surface of virus-infected donor cells and target cells, as well as on the envelope of HIV-1 virions1,4,5,6,7,13. VS formation is also accompanied by intracellular signaling events that are transduced as a result of gp120-engagement of its receptors. Indeed, we have recently showed that CD4+ T cell interaction with gp120 induces recruitment and phosphorylation of signaling molecules associated with the TCR signalosome including Lck, CD3&zeta;, ZAP70, LAT, SLP-76, Itk, and PLC&gamma;15.
In this article, we present a method to visualize supramolecular arrangement and membrane-proximal signaling events taking place during VS formation. We take advantage of the glass-supported planar bi-layer system as a reductionist model to represent the surface of HIV-infected cells bearing the viral envelope gp120 and the cellular adhesion molecule ICAM-1. The protocol describes general procedures for monitoring HIV-1 gp120-induced VS assembly and signal activation events that include i) bi-layer preparation and assembly in a flow cell, ii) injection of cells and immunofluorescence staining to detect intracellular signaling molecules on cells interacting with HIV-1 gp120 and ICAM-1 on bi-layers, iii) image acquisition by TIRF microscopy, and iv) data analysis. This system generates high-resolution images of VS interface beyond that achieved with the conventional cell-cell system as it allows detection of distinct clusters of individual molecular components of VS along with specific signaling molecules recruited to these sub-domains.

This article describes a method to visualize formation of an HIV-1 envelope-induced virological synapse on glass supported planar bilayers by total internal reflection fluorescence (TIRF) microscopy. The method can also be combined with immunofluorescence staining to detect activation and redistribution of signaling molecules that occur during HIV-1 envelope-induced virological synapse formation.

Imagem do HIV-1 Synapse Envelope induzida virológica e Sinalização em bicamadas lipídicas sintéticas

Human immunodeficiency virus type 1 (HIV-1) infection occurs most efficiently via cell to cell transmission2,10,11. This cell to cell transfer between ...

Imunologia e Infecção

Infection of Zebrafish Embryos with Intracellular Bacterial Pathogens

Zebrafish (Danio rerio) embryos are increasingly used as a model for studying the function of the vertebrate innate immune system in host-pathogen interactions 1. The major cell types of the innate immune system, macrophages and neutrophils, develop during the first days of embryogenesis prior to the maturation of lymphocytes that are required for adaptive immune responses. The ease of obtaining large numbers of embryos, their accessibility due to external development, the optical transparency of embryonic and larval stages, a wide range of genetic tools, extensive mutant resources and collections of transgenic reporter lines, all add to the versatility of the zebrafish model. Salmonella enterica serovar Typhimurium (S. typhimurium) and Mycobacterium marinum can reside intracellularly in macrophages and are frequently used to study host-pathogen interactions in zebrafish embryos. The infection processes of these two bacterial pathogens are interesting to compare because S. typhimurium infection is acute and lethal within one day, whereas M. marinum infection is chronic and can be imaged up to the larval stage 2, 3. The site of micro-injection of bacteria into the embryo (Figure 1) determines whether the infection will rapidly become systemic or will initially remain localized. A rapid systemic infection can be established by micro-injecting bacteria directly into the blood circulation via the caudal vein at the posterior blood island or via the Duct of Cuvier, a wide circulation channel on the yolk sac connecting the heart to the trunk vasculature. At 1 dpf, when embryos at this stage have phagocytically active macrophages but neutrophils have not yet matured, injecting into the blood island is preferred. For injections at 2-3 dpf, when embryos also have developed functional (myeloperoxidase-producing) neutrophils, the Duct of Cuvier is preferred as the injection site. To study directed migration of myeloid cells towards local infections, bacteria can be injected into the tail muscle, otic vesicle, or hindbrain ventricle 4-6. In addition, the notochord, a structure that appears to be normally inaccessible to myeloid cells, is highly susceptible to local infection 7. A useful alternative for high-throughput applications is the injection of bacteria into the yolk of embryos within the first hours after fertilization 8. Combining fluorescent bacteria and transgenic zebrafish lines with fluorescent macrophages or neutrophils creates ideal circumstances for multi-color imaging of host-pathogen interactions. This video article will describe detailed protocols for intravenous and local infection of zebrafish embryos with S. typhimurium or M. marinum bacteria and for subsequent fluorescence imaging of the interaction with cells of the innate immune system.

Transparent zebrafish embryos have proved useful model hosts to visualize and functionally study interactions between innate immune cells and intracellular bacterial pathogens, such as Salmonella typhimurium and Mycobacterium marinum. Micro-injection of bacteria and multi-color fluorescence imaging are essential techniques involved in the application of zebrafish embryo infection models.

A infecção de embriões de zebrafish com patógenos bacterianos intracelulares

Zebrafish (Danio rerio) embryos are increasingly used as a model for studying the function of the vertebrate innate immune system in host-pathogen ...

Growth of Mycobacterium tuberculosis Biofilms

Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, has an extraordinary ability to survive against environmental stresses including antibiotics. Although stress tolerance of M. tuberculosis is one of the likely contributors to the 6-month long chemotherapy of tuberculosis 1, the molecular mechanisms underlying this characteristic phenotype of the pathogen remain unclear. Many microbial species have evolved to survive in stressful environments by self-assembling in highly organized, surface attached, and matrix encapsulated structures called biofilms 2-4. Growth in communities appears to be a preferred survival strategy of microbes, and is achieved through genetic components that regulate surface attachment, intercellular communications, and synthesis of extracellular polymeric substances (EPS) 5,6. The tolerance to environmental stress is likely facilitated by EPS, and perhaps by the physiological adaptation of individual bacilli to heterogeneous microenvironments within the complex architecture of biofilms 7.
In a series of recent papers we established that M. tuberculosis and Mycobacterium smegmatis have a strong propensity to grow in organized multicellular structures, called biofilms, which can tolerate more than 50 times the minimal inhibitory concentrations of the anti-tuberculosis drugs isoniazid and rifampicin 8-10. M. tuberculosis, however, intriguingly requires specific conditions to form mature biofilms, in particular 9:1 ratio of headspace: media as well as limited exchange of air with the atmosphere 9. Requirements of specialized environmental conditions could possibly be linked to the fact that M. tuberculosis is an obligate human pathogen and thus has adapted to tissue environments. In this publication we demonstrate methods for culturing M. tuberculosis biofilms in a bottle and a 12-well plate format, which is convenient for bacteriological as well as genetic studies. We have described the protocol for an attenuated strain of M. tuberculosis, mc27000, with deletion in the two loci, panCD and RD1, that are critical for in vivo growth of the pathogen 9. This strain can be safely used in a BSL-2 containment for understanding the basic biology of the tuberculosis pathogen thus avoiding the requirement of an expensive BSL-3 facility. The method can be extended, with appropriate modification in media, to grow biofilm of other culturable mycobacterial species.
Overall, a uniform protocol of culturing mycobacterial biofilms will help the investigators interested in studying the basic resilient characteristics of mycobacteria. In addition, a clear and concise method of growing mycobacterial biofilms will also help the clinical and pharmaceutical investigators to test the efficacy of a potential drug.

Growth of Mycobacterium tuberculosis Biofilms

Mycobacterium tuberculosis forms drug tolerant biofilms when cultured in certain conditions. Here we describe methods for culturing M. tuberculosis biofilms and determining the frequency of drug tolerant persisters. These protocols will be useful for further studies into the mechanisms of drug tolerance in M. tuberculosis.

Crescimento de Mycobacterium tuberculosis Biofilmes

Mycobacterium tuberculosis, the etiologic agent of human tuberculosis, has an extraordinary ability to survive against environmental stresses including ...

Non-invasive Imaging of Disseminated Candidiasis in Zebrafish Larvae

Disseminated candidiasis caused by the pathogen Candida albicans is a clinically important problem in hospitalized individuals and is associated with a 30 to 40% attributable mortality6. Systemic candidiasis is normally controlled by innate immunity, and individuals with genetic defects in innate immune cell components such as phagocyte NADPH oxidase are more susceptible to candidemia7-9. Very little is known about the dynamics of C. albicans interaction with innate immune cells in vivo. Extensive in vitro studies have established that outside of the host C. albicans germinates inside of macrophages, and is quickly destroyed by neutrophils10-14. In vitro studies, though useful, cannot recapitulate the complex in vivo environment, which includes time-dependent dynamics of cytokine levels, extracellular matrix attachments, and intercellular contacts10, 15-18. To probe the contribution of these factors in host-pathogen interaction, it is critical to find a model organism to visualize these aspects of infection non-invasively in a live intact host. 
The zebrafish larva offers a unique and versatile vertebrate host for the study of infection. For the first 30 days of development zebrafish larvae have only innate immune defenses2, 19-21, simplifying the study of diseases such as disseminated candidiasis that are highly dependent on innate immunity. The small size and transparency of zebrafish larvae enable imaging of infection dynamics at the cellular level for both host and pathogen. Transgenic larvae with fluorescing innate immune cells can be used to identify specific cells types involved in infection22-24. Modified anti-sense oligonucleotides (Morpholinos) can be used to knock down various immune components such as phagocyte NADPH oxidase and study the changes in response to fungal infection5. In addition to the ethical and practical advantages of using a small lower vertebrate, the zebrafish larvae offers the unique possibility to image the pitched battle between pathogen and host both intravitally and in color. 
The zebrafish has been used to model infection for a number of human pathogenic bacteria, and has been instrumental in major advances in our understanding of mycobacterial infection3, 25. However, only recently have much larger pathogens such as fungi been used to infect larva5, 23, 26, and to date there has not been a detailed visual description of the infection methodology. Here we present our techniques for hindbrain ventricle microinjection of prim25 zebrafish, including our modifications to previous protocols. Our findings using the larval zebrafish model for fungal infection diverge from in vitro studies and reinforce the need to examine the host-pathogen interaction in the complex environment of the host rather than the simplified system of the Petri dish5.

The rapid development, small size and transparency of zebrafish are tremendous advantages for the study of innate immune control of infection1-4. Here we demonstrate techniques for infecting zebrafish larvae using the fungal pathogen Candida albicans by microinjection, methodology recently used to implicate phagocyte NADPH oxidase activity in control of fungal dimorphism5.

Não-invasivos de imagem de candidíase disseminada em larvas do peixe

Disseminated candidiasis caused by the pathogen Candida albicans is a clinically important problem in hospitalized individuals and is associated with a 30 ...

Imaging Mycobacterium tuberculosis in Mice with Reporter Enzyme Fluorescence

Reporter enzyme fluorescence (REF) utilizes substrates that are specific for enzymes present in target organisms of interest for imaging or detection by fluorescence or bioluminescence. We utilize BlaC, an enzyme expressed constitutively by all M. tuberculosis strains. REF allows rapid quantification of bacteria in lungs of infected mice. The same group of mice can be imaged at many time points, greatly reducing costs, enumerating bacteria more quickly, allowing novel observations in host-pathogen interactions, and increasing statistical power, since more animals per group are readily maintained. REF is extremely sensitive due to the catalytic nature of the BlaC enzymatic reporter and specific due to the custom flourescence resonance energy transfer (FRET) or fluorogenic substrates used. REF does not require recombinant strains, ensuring normal host-pathogen interactions. We describe the imaging of M. tuberculosis infection using a FRET substrate with maximal emission at 800 nm. The wavelength of the substrate allows sensitive deep tissue imaging in mammals. We will outline aerosol infection of mice with M. tuberculosis, anesthesia of mice, administration of the REF substrate, and optical imaging. This method has been successfully applied to evaluating host-pathogen interactions and efficacy of antibiotics targeting M. tuberculosis.

Imaging Mycobacterium tuberculosis in Mice with Reporter Enzyme Fluorescence

We describe the optical imaging of mice infected with Mycobacterium tuberculosis (M. tuberculosis) using reporter enzyme fluorescence (REF). This protocol facilitates the sensitive and specific detection of M. tuberculosis in pre-clinical animal models for pathogenesis, therapeutics and vaccine research.

Mycobacterium tuberculosis em camundongos com fluorescência de enzima do repórter de imagem

Reporter enzyme fluorescence (REF) utilizes substrates that are specific for enzymes present in target organisms of interest for imaging or detection by ...

Identification of Virulence Markers of Mycobacterium abscessus for Intracellular Replication in Phagocytes

What differentiates Mycobacterium abscessus from other saprophytic mycobacteria is the ability to resist phagocytosis by human macrophages and the ability to multiply inside such cells. These virulence traits render M. abscessus pathogenic, especially in vulnerable hosts with underlying structural lung disease, such as cystic fibrosis, bronchiectasis or tuberculosis. How patients become infected with M. abscessus remains unclear. Unlike many mycobacteria, M. abscessus is not found in the environment but might reside inside amoebae, environmental phagocytes that represent a potential reservoir for M. abscessus. Indeed, M. abscessus is resistant to amoebal phagocytosis and the intra-amoeba life seems to increase M. abscessus virulence in an experimental model of infection. However, little is known about M. abscessus virulence in itself. To decipher the genes conferring an advantage to M. abscessus intracellular life, a screening of a M. abscessus transposon mutant library was developed. In parallel, a method of RNA extraction from intracellular Mycobacteria after co-culture with amoebae was developed. This method was validated and allowed the sequencing of whole M. abscessus transcriptomes inside the cells; providing, for the first time, a global view on M. abscessus adaptation to intracellular life. Both approaches give us an insight into M. abscessus virulence factors that enable M. abscessus to colonize the airways in humans.

Identification of Virulence Markers of Mycobacterium abscessus for Intracellular Replication in Phagocytes

Here, we present two protocols to study Phagocyte-Mycobacterium abscessus interactions: the screening of a transposon mutant library for bacterial intracellular deficiency and the determination of bacterial intracellular transcriptome from RNA sequencing. Both approaches provide insight into the genomic advantages and transcriptomic adaptations enhancing intracellular bacteria fitness.

Identificação de marcadores de virulência de Mycobacterium abscessus para replicação intracelular em fagócitos

What differentiates Mycobacterium abscessus from other saprophytic mycobacteria is the ability to resist phagocytosis by human macrophages and the ability ...

Modeling Tuberculosis in Mycobacterium marinum Infected Adult Zebrafish

Mycobacterium tuberculosis is currently the deadliest human pathogen causing 1.7 million deaths and 10.4 million infections every year. Exposure to this bacterium causes a wide disease spectrum in humans ranging from a sterilized infection to an actively progressing deadly disease. The most common form is the latent tuberculosis, which is asymptomatic, but has the potential to reactivate into a fulminant disease. Adult zebrafish and its natural pathogen Mycobacterium marinum have recently proven to be an applicable model to study the wide disease spectrum of tuberculosis. Importantly, spontaneous latency and reactivation as well as adaptive immune responses in the context of mycobacterial infection can be studied in this model. In this article, we describe methods for the experimental infection of adult zebrafish, the collection of internal organs for the extraction of nucleic acids for the measurement of mycobacterial loads and host immune responses by quantitative PCR. The in-house-developed, M. marinum-specific qPCR assay is more sensitive than the traditional plating methods as it also detects DNA from non-dividing, dormant or recently dead mycobacteria. As both DNA and RNA are extracted from the same individual, it is possible to study the relationships between the diseased state, and the host and pathogen gene-expression. The adult zebrafish model for tuberculosis thus presents itself as a highly applicable, non-mammalian in vivo system to study host-pathogen interactions.

Modeling Tuberculosis in Mycobacterium marinum Infected Adult Zebrafish

Here, we present a protocol to model human tuberculosis in an adult zebrafish using its natural pathogen Mycobacterium marinum. Extracted DNA and RNA from the internal organs of infected zebrafish can be used to reveal the total mycobacterial loads in the fish and the host&#39;s immune responses with qPCR.

Modelagem de tuberculose no Zebrafish adulto infectado de Mycobacterium marinum

Mycobacterium tuberculosis is currently the deadliest human pathogen causing 1.7 million deaths and 10.4 million infections every year. Exposure to this ...

Adoptive Immunotherapy of iNKT Cells in Glucose-6-Phosphate Isomerase (G6PI)-Induced RA Mice

Rheumatoid arthritis (RA) is a complex chronic inflammatory autoimmune disease. The pathogenesis of the disease is related to invariant natural killer T (iNKT) cells. Patients with active RA present fewer iNKT cells, defective cell function, and excessive polarization of Th1. In this study, an RA animal model was established using a mixture of hGPI325-339 and hGPI469-483 peptides. The iNKT cells were obtained by in vivo induction and in vitro purification, followed by infusion into RA mice for adoptive immunotherapy. The in vivo imaging system (IVIS) tracking revealed that iNKT cells were mainly distributed in the spleen and liver. On day 12 after cell therapy, the disease progression slowed down significantly, the clinical symptoms were alleviated, the abundance of iNKT cells in the thymus increased, the proportion of iNKT1 in the thymus decreased, and the levels of TNF-&#945;, IFN-&#947;, and IL-6 in the serum decreased. Adoptive immunotherapy of iNKT cells restored the balance of immune cells and corrected the excessive inflammation of the body.

Adoptive Immunotherapy of iNKT Cells in Glucose-6-Phosphate Isomerase G6PI-Induced RA Mice

This protocol uses G6PI mixed peptides to construct rheumatoid arthritis models that are closer to that of human rheumatoid arthritis in CD4+ T cells and cytokines. High purity invariant natural killer T cells (mainly iNKT2) with specific phenotypes and functions were obtained by in vivo induction and in vitro purification for adoptive immunotherapy.

Imunoterapia adotiva de células iNKT em Isomerase Isomerase Induzida de Glicose-6-Fosfato (G6PI)-Induzido RaMice

Rheumatoid arthritis (RA) is a complex chronic inflammatory autoimmune disease. The pathogenesis of the disease is related to invariant natural killer T ...

Visualization of Macrophage Lytic Cell Death During Mycobacterial Infection in Zebrafish Embryos via Intravital Microscopy

Zebrafish is an excellent model organism for studying innate immune cell behavior due to its transparent nature and reliance solely on its innate immune system during early development. The Zebrafish Mycobacterium marinum (M. marinum) infection model has been well-established in studying host immune response against mycobacterial infection. It has been suggested that different macrophage cell death types will lead to the diverse outcomes of mycobacterial infection. Here we describe a protocol using intravital microscopy to observe macrophage cell death in zebrafish embryos following M. marinum infection. Zebrafish transgenic lines that specifically label macrophages and neutrophils are infected via intramuscular microinjection of fluorescently labeled M. marinum in either the midbrain or the trunk. Infected zebrafish embryos are subsequently mounted on low melting agarose and observed by confocal microscopy in X-Y-Z-T dimensions. Because long-term live imaging requires using low laser power to avoid photobleaching and phototoxicity, a strongly expressing transgenic is highly recommended. This protocol facilitates the visualization of the dynamic processes in vivo, including immune cell migration, host pathogen interaction, and cell death.

This protocol describes a technique for visualizing macrophage behavior and death in embryonic zebrafish during Mycobacterium marinum infection. Steps for the preparation of bacteria, infection of the embryos, and intravital microscopy are included. This technique may be applied to the observation of cellular behavior and death in similar scenarios involving infection or sterile inflammation.

Visualização da morte de células ticas de macrófago durante infecção micobacteriana em embriões de zebrafish via microscopia intravital

Zebrafish is an excellent model organism for studying innate immune cell behavior due to its transparent nature and reliance solely on its innate immune ...

Phage Therapy Application to Counteract Pseudomonas aeruginosa Infection in Cystic Fibrosis Zebrafish Embryos

Antimicrobial resistance, a major consequence of diagnostic uncertainty and antimicrobial overprescription, is an increasingly recognized cause of severe infections, complications, and mortality worldwide with a huge impact on our society and on the health system. In particular, patients with compromised immune systems or pre-existing and chronic pathologies, such as cystic fibrosis (CF), are subjected to frequent antibiotic treatments to control the infections with the appearance and diffusion of multidrug resistant isolates. Therefore, there is an urgent need to address alternative therapies to counteract bacterial infections. Use of bacteriophages, the natural enemies of bacteria, can be a possible solution. The protocol detailed in this work describes the application of phage therapy against Pseudomonas aeruginosa infection in CF zebrafish embryos. Zebrafish embryos were infected with P. aeruginosa to demonstrate that phage therapy is effective against P. aeruginosa infections as it reduces lethality, bacterial burden and pro-inflammatory immune response in CF embryos.

Phage Therapy Application to Counteract Pseudomonas aeruginosa Infection in Cystic Fibrosis Zebrafish Embryos

Presented here is a protocol for Pseudomonas aeruginosa infection and phage therapy application in cystic fibrosis (CF) zebrafish embryos.

Aplicação de terapia phage para neutralizar pseudomonas aeruginosa infecção em embriões de zebrafish fibrose cística

Antimicrobial resistance, a major consequence of diagnostic uncertainty and antimicrobial overprescription, is an increasingly recognized cause of severe ...