Real-Time Observation of Listeria monocytogenes-Phagocyte Interactions in Living Zebrafish Larvae

ABSTRACT The zebrafish, Danio rerio, has become a popular vertebrate model for the study of infections, mainly because of its excellent optical accessibility at the embryonic and larval stages, when the innate immune system is already effective. We have thus tested the susceptibility of zebrafish larvae to the human pathogen Listeria monocytogenes, a gram-positive, facultative, intracellular bacterium that is known to survive and multiply in professional phagocytes and that causes fatal meningitis and abortions. Intravenous injection of early zebrafish larvae resulted in a progressive and ultimately fatal infection. Blood-borne L. monocytogenes bacteria were quickly trapped and engulfed by macrophages, an event that, for the first time, could be captured in vivo and in real time. Granulocytes also participated in the innate immune response. As in mammals, bacteria could escape the macrophage phagosome in a listeriolysin-dependent manner and accessed the cytosol; this event was critical for bacterial virulence, as listeriolysin-deficient bacteria were completely avirulent. Actin comet tails and protrusions were observed, suggesting cell-to-cell spread; these phenomena also played a role in virulence in zebrafish larvae, as actA-deficient bacteria were attenuated. These results demonstrate the relevance of the genetically tractable and optically accessible zebrafish model for the study of L. monocytogenes pathogenesis and particularly for the dissection of its interactions with phagocytes in vivo, a key factor of L. monocytogenes virulence.

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Mn Inhibits GSH Synthesis via Downregulation of Neuronal EAAC1 and Astrocytic xCT to Cause Oxidative Damage in the Striatum of Mice

Oxidative Medicine and Cellular Longevity ◽

10.1155/2018/4235695 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 7

Author(s):

Xinxin Yang ◽

Haibo Yang ◽

Fengdi Wu ◽

Zhipeng Qi ◽

Jiashuo Li ◽

...

Keyword(s):

Oxidative Stress ◽

Oxidative Damage ◽

Dependent Manner ◽

Protein Levels ◽

Key Factor ◽

Protein Sulfhydryl ◽

Mrna And Protein Expression ◽

The Brain

Excessive manganese (Mn) can accumulate in the striatum of the brain following overexposure. Oxidative stress is a well-recognized mechanism in Mn-induced neurotoxicity. It has been proven that glutathione (GSH) depletion is a key factor in oxidative damage during Mn exposure. However, no study has focused on the dysfunction of GSH synthesis-induced oxidative stress in the brain during Mn exposure. The objective of the present study was to explore the mechanism of Mn disruption of GSH synthesis via EAAC1 and xCT in vitro and in vivo. Primary neurons and astrocytes were cultured and treated with different doses of Mn to observe the state of cells and levels of GSH and reactive oxygen species (ROS) and measure mRNA and protein expression of EAAC1 and xCT. Mice were randomly divided into seven groups, which received saline, 12.5, 25, and 50 mg/kg MnCl2, 500 mg/kg AAH (EAAC1 inhibitor) + 50 mg/kg MnCl2, 75 mg/kg SSZ (xCT inhibitor) + 50 mg/kg MnCl2, and 100 mg/kg NAC (GSH rescuer) + 50 mg/kg MnCl2 once daily for two weeks. Then, levels of EAAC1, xCT, ROS, GSH, malondialdehyde (MDA), protein sulfhydryl, carbonyl, 8-hydroxy-2-deoxyguanosine (8-OHdG), and morphological and ultrastructural features in the striatum of mice were measured. Mn reduced protein levels, mRNA expression, and immunofluorescence intensity of EAAC1 and xCT. Mn also decreased the level of GSH, sulfhydryl, and increased ROS, MDA, 8-OHdG, and carbonyl in a dose-dependent manner. Injury-related pathological and ultrastructure changes in the striatum of mice were significantly present. In conclusion, excessive exposure to Mn disrupts GSH synthesis through inhibition of EAAC1 and xCT to trigger oxidative damage in the striatum.

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Protective Effect of Phillyrin on Lethal LPS-Induced Neutrophil Inflammation in Zebrafish

Cellular Physiology and Biochemistry ◽

10.1159/000484192 ◽

2017 ◽

Vol 43 (5) ◽

pp. 2074-2087 ◽

Cited By ~ 19

Author(s):

Liling Yang ◽

Xiangjun Zhou ◽

Weijuan Huang ◽

Qin Fang ◽

Jianlan Hu ◽

...

Keyword(s):

Signalling Pathway ◽

Dependent Manner ◽

Zebrafish Model ◽

Lps Challenge ◽

Cell Counts ◽

Tnf Α ◽

Forsythia Suspensa ◽

Anti Inflammatory

Background/Aims: Forsythia suspensa Vahl. (Oleaceae) fruits are widely used in traditional Chinese medicine to treat pneumonia, typhoid, dysentery, ulcers and oedema. Antibacterial and anti-inflammatory activities have been reported for phillyrin (PHN), the main ingredient in Forsythia suspensa Vahl fruits, in vitro. However, the underlying mechanisms in vivo remain poorly defined. In this study, we discovered that PHN exerted potent anti-inflammatory effects in lethal LPS-induced neutrophil inflammation by suppressing the MyD88-dependent signalling pathway in zebrafish. Methods: LPS-yolk microinjection was used to induce a lethal LPS-infected zebrafish model. The effect of PHN on the survival of zebrafish challenged with lethal LPS was evaluated using survival analysis. The effect of PHN on neutrophil inflammation grading in vivo was assessed by tracking neutrophils with a transgenic line. The effects of PHN on neutrophil production and migration were analysed by SB+ cell counts during consecutive hours after modelling. Additionally, key cytokines and members of the MyD88 signalling pathway that are involved in inflammatory response were detected using quantitative RT-PCR. To assess gene expression changes during consecutive hours after modelling, the IL-1β, IL-6, TNF-α, MyD88, TRIF, ERK1/2, JNK, IκBa and NF-κB expression levels were measured. Results: PHN could protect zebrafish against a lethal LPS challenge in a dose-dependent manner, as indicated by decreased neutrophil infltration, reduced tissue necrosis and increased survival rates. Up-regulated IL-1β, IL-6 and TNF-α expression also showed the same tendencies of depression by PHN. Critically, PHN significantly inhibited the LPS-induced activation of MyD88, IκBa, and NF-κB but did not affect the expression of ERK1/2 MAPKs or JNK MAPKs in LPS-stimulated zebrafish. Additionally, PHN regulated the MyD88/IκBα/NF-κB signalling pathway by controlling IκBα, IL-1β, IL-6, and TNF-α expression. Conclusion: This study provides a rationale for the clinical application of PHN as an anti-inflammatory agent.

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(-)-Epigallocatechin Gallate Promotes MicroRNA 145 Expression against Myocardial Hypoxic Injury through Dab2/Wnt3a/β-catenin

The American Journal of Chinese Medicine ◽

10.1142/s0192415x20500172 ◽

2020 ◽

Vol 48 (02) ◽

pp. 341-356

Author(s):

Chiu-Mei Lin ◽

Wei-Jen Fang ◽

Bao-Wei Wang ◽

Chun-Ming Pan ◽

Su-Kiat Chua ◽

...

Keyword(s):

Myocardial Infarction ◽

Real Time ◽

Real Time Pcr ◽

Myocardial Infarct ◽

Epigallocatechin Gallate ◽

Dependent Manner ◽

Concentration Dependent Manner ◽

Rat Cardiomyocytes

MicroRNA 145 (miR-145) is a critical modulator of cardiovascular diseases. The downregulation of myocardial miR-145 is followed by an increase in disabled-2 (Dab2) expression in cardiomyocytes. (-)-epigallocatechin gallate (EGCG) is a flavonoid that has been evaluated extensively due to its diverse pharmacological properties including anti-inflammatory effects. The aim of this study was to investigate the cardioprotective effects of EGCG under hypoxia-induced stress in vitro and in vivo. The hypoxic insult led to the suppression of miR-145 expression in cultured rat cardiomyocytes in a concentration-dependent manner. Western blotting and real-time PCR were performed. In rat myocardial infarction study, in situ hybridization, and immunofluorescent analyses were adopted. The western blot and real-time PCR data revealed that hypoxic stress with 2.5% O2 suppressed the expression of miR-145 and Wnt3a/[Formula: see text]-catenin in cultured rat cardiomyocytes but augmented Dab2. Treatment with EGCG attenuated Dab2 expression, but increased Wnt3a and [Formula: see text]-catenin in hypoxic cultured cardiomyocytes. Following in vivo myocardial infarction (MI) study, the data revealed the myocardial infarct area reduced by 48.5%, 44.6%, and 48.5% in EGCG (50[Formula: see text]mg/kg) or miR-145 dominant or Dab2 siRNA groups after myocardial infarction for 28 days, respectively. This study demonstrated that EGCG increased miR-145, Wnt3a, and [Formula: see text]-catenin expression but attenuated Dab2 expression. Moreover, EGCG ameliorated myocardial ischemia in vivo. The novel suppressive effect was mediated through the miR-145 and Dab2/Wnt3a/[Formula: see text]-catenin pathways.

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Effects of Regulatory T Cell Depletion on NK Cell Responses against Listeria monocytogenes in Feline Immunodeficiency Virus Infected Cats

Viruses ◽

10.3390/v11110984 ◽

2019 ◽

Vol 11 (11) ◽

pp. 984

Author(s):

Simões ◽

LaVoy ◽

Dean

Keyword(s):

Immune Response ◽

Listeria Monocytogenes ◽

Dendritic Cell ◽

Innate Immune Response ◽

Feline Immunodeficiency Virus ◽

Innate Immune ◽

Treg Depletion ◽

Cell Responses ◽

Immunodeficiency Virus

Regulatory T cells (Treg) are key players in the maintenance of peripheral tolerance, preventing autoimmune diseases and restraining chronic inflammatory diseases. Evidence suggests Treg cells and NK cells have important roles in feline immunodeficiency virus (FIV) pathogenesis; however, in vivo studies investigating the interplay between these two cell populations are lacking. We previously described innate immune defects in FIV-infected cats characterized by cytokine deficits and impaired natural killer cell (NK) and NK T cell (NKT) functions. In this study, we investigated whether in vivo Treg depletion by treatment with an anti-feline CD25 monoclonal antibody would improve the innate immune response against subcutaneous challenge with Listeria monocytogenes (Lm). Treg depletion resulted in an increased overall number of cells in Lm-draining lymph nodes and increased proliferation of NK and NKT cells in FIV-infected cats. Treg depletion did not normalize expression of perforin or granzyme A by NK and NKT cells, nor did Treg depletion result in improved clearance of Lm. Thus, despite the quantitative improvements in the NK and NKT cell responses to Lm, there was no functional improvement in the early control of Lm. CD1a+ dendritic cell percentages in the lymph nodes of FIV-infected cats were lower than in specific-pathogen-free control cats and failed to upregulate CD80 even when Treg were depleted. Taken together, Treg depletion failed to improve the innate immune response of FIV-infected cats against Lm and this may be due to dendritic cell dysfunction.

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Robust Phagocyte Recruitment Controls the Opportunistic Fungal PathogenMucor circinelloidesin Innate GranulomasIn Vivo

mBio ◽

10.1128/mbio.02010-17 ◽

2018 ◽

Vol 9 (2) ◽

Cited By ~ 12

Author(s):

Sarah Inglesfield ◽

Aleksandra Jasiulewicz ◽

Matthew Hopwood ◽

James Tyrrell ◽

George Youlden ◽

...

Keyword(s):

Immune Response ◽

Fungal Infection ◽

Real Time ◽

Clinical Management ◽

In Silico ◽

Innate Immune ◽

Granuloma Formation ◽

Early Immune Response ◽

Latent Stage

ABSTRACTMucormycosis is an emerging fungal infection with extremely high mortality rates in patients with defects in their innate immune response, specifically in functions mediated through phagocytes. However, we currently have a limited understanding of the molecular and cellular interactions between these innate immune effectors and mucormycete spores during the early immune response. Here, the early events of innate immune recruitment in response to infection byMucor circinelloidesspores are modeled by a combinedin silicomodeling approach and real-timein vivomicroscopy. Phagocytes are rapidly recruited to the site of infection in a zebrafish larval model of mucormycosis. This robust early recruitment protects from disease onsetin vivo.In silicoanalysis identified that protection is dependent on the number of phagocytes at the infection site, but not the speed of recruitment. The mathematical model highlights the role of proinflammatory signals for phagocyte recruitment and the importance of inhibition of spore germination for protection from active fungal disease. Thesein silicodata are supported by anin vivolack of fungal spore killing and lack of reactive oxygen burst, which together result in latent fungal infection. During this latent stage of infection, spores are controlled in innate granulomasin vivo. Disease can be reactivated by immunosuppression. Together, these data represent the firstin vivoreal-time analysis of innate granuloma formation during the early stages of a fungal infection. The results highlight a potential latent stage during mucormycosis that should urgently be considered for clinical management of patients.IMPORTANCEMucormycosis is a dramatic fungal infection frequently leading to the death of patients. We know little about the immune response to the fungus causing this infection, although evidence points toward defects in early immune events after infection. Here, we dissect this early immune response to infectious fungal spores. We show that specialized white blood cells (phagocytes) rapidly respond to these spores and accumulate around the fungus. However, we demonstrate that the mechanisms that enable phagocytes to kill the fungus fail, allowing for survival of spores. Instead a cluster of phagocytes resembling an early granuloma is formed around spores to control the latent infection. This study is the first detailed analysis of early granuloma formation during a fungal infection highlighting a latent stage that needs to be considered for clinical management of patients.

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RIPK1 activates distinct gasdermins in macrophages and neutrophils upon pathogen blockade of innate immune signalling

10.1101/2021.01.20.427379 ◽

2021 ◽

Author(s):

Kaiwen W. Chen ◽

Benjamin Demarco ◽

Rosalie Heilig ◽

Saray P Ramos ◽

James P Grayczyk ◽

...

Keyword(s):

Effector Proteins ◽

Innate Immune ◽

Target Cells ◽

Caspase 8 ◽

Dependent Manner ◽

Wild Type ◽

Mapk Signalling ◽

Common Strategy ◽

Deficient Mice

AbstractInjection of effector proteins to block host innate immune signalling is a common strategy used by many pathogenic organisms to establish an infection. Pathogenic Yersinia species for example inject the acetyltransferase YopJ into target cells to inhibit NF-κB and MAPK signalling. To counteract this, detection of YopJ activity in myeloid cells promotes the assembly of a RIPK1-caspase-8 death-inducing platform that confers antibacterial defence. While recent studies revealed that caspase-8 cleaves the pore-forming protein, gasdermin D (GSDMD) to trigger pyroptosis in macrophages, whether RIPK1 activates additional substrates downstream of caspase-8 to promote host defence is unclear. Here, we report that the related gasdermin family member gasdermin E (GSDME) is activated upon detection of YopJ activity in a RIPK1 kinase-dependent manner. Specifically, GSDME promotes neutrophil pyroptosis and IL-1β release, which is critical for anti-Yersinia defence. During in vivo infection, IL-1β neutralisation increases bacterial burden in wild type but not Gsdme-deficient mice. Thus, our study establishes GSDME as an important mediator that counteracts pathogen blockade of innate immune signalling.

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Early detection of doxorubicin-induced cardiotoxicity in rats by its cardiac metabolic signature assessed with hyperpolarized MRI

Communications Biology ◽

10.1038/s42003-020-01440-z ◽

2020 ◽

Vol 3 (1) ◽

Cited By ~ 1

Author(s):

Kerstin N. Timm ◽

Charith Perera ◽

Vicky Ball ◽

John A. Henry ◽

Jack J. Miller ◽

...

Keyword(s):

Mitochondrial Dysfunction ◽

Real Time ◽

Chemotherapeutic Agent ◽

Imaging Techniques ◽

Functional Decline ◽

Metabolic Fluxes ◽

Key Factor ◽

Hyperpolarized Mri ◽

Magnetic Resonance Imaging Mri

AbstractDoxorubicin (DOX) is a widely used chemotherapeutic agent that can cause serious cardiotoxic side effects culminating in congestive heart failure (HF). There are currently no clinical imaging techniques or biomarkers available to detect DOX-cardiotoxicity before functional decline. Mitochondrial dysfunction is thought to be a key factor driving functional decline, though real-time metabolic fluxes have never been assessed in DOX-cardiotoxicity. Hyperpolarized magnetic resonance imaging (MRI) can assess real-time metabolic fluxes in vivo. Here we show that cardiac functional decline in a clinically relevant rat-model of DOX-HF is preceded by a change in oxidative mitochondrial carbohydrate metabolism, measured by hyperpolarized MRI. The decreased metabolic fluxes were predominantly due to mitochondrial loss and additional mitochondrial dysfunction, and not, as widely assumed hitherto, to oxidative stress. Since hyperpolarized MRI has been successfully translated into clinical trials this opens up the potential to test cancer patients receiving DOX for early signs of cardiotoxicity.

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XCR1+ dendritic cells promote memory CD8+ T cell recall upon secondary infections with Listeria monocytogenes or certain viruses

Journal of Experimental Medicine ◽

10.1084/jem.20142350 ◽

2015 ◽

Vol 213 (1) ◽

pp. 75-92 ◽

Cited By ~ 56

Author(s):

Yannick O. Alexandre ◽

Sonia Ghilas ◽

Cindy Sanchez ◽

Agnès Le Bon ◽

Karine Crozat ◽

...

Keyword(s):

Dendritic Cells ◽

Listeria Monocytogenes ◽

T Cell ◽

Nk Cells ◽

Nk Cell ◽

Infectious Agent ◽

Cd8 T Cell ◽

Dependent Manner ◽

Secondary Infections

Naive CD8+ T cell priming during tumor development or many primary infections requires cross-presentation by XCR1+ dendritic cells (DCs). Memory CD8+ T lymphocytes (mCTLs) harbor a lower activation threshold as compared with naive cells. However, whether their recall responses depend on XCR1+ DCs is unknown. By using a new mouse model allowing fluorescent tracking and conditional depletion of XCR1+ DCs, we demonstrate a differential requirement of these cells for mCTL recall during secondary infections by different pathogens. XCR1+ DCs were instrumental to promote this function upon secondary challenges with Listeria monocytogenes, vesicular stomatitis virus, or Vaccinia virus, but dispensable in the case of mouse cytomegalovirus. We deciphered how XCR1+ DCs promote mCTL recall upon secondary infections with Listeria. By visualizing for the first time the in vivo choreography of XCR1+ DCs, NK cells and mCTLs during secondary immune responses, and by neutralizing in vivo candidate molecules, we demonstrate that, very early after infection, mCTLs are activated, and attracted in a CXCR3-dependent manner, by NK cell–boosted, IL-12–, and CXCL9-producing XCR1+ DCs. Hence, depending on the infectious agent, strong recall of mCTLs during secondary challenges can require cytokine- and chemokine-dependent cross-talk with XCR1+ DCs and NK cells.

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RIPK1 activates distinct gasdermins in macrophages and neutrophils upon pathogen blockade of innate immune signaling

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2101189118 ◽

2021 ◽

Vol 118 (28) ◽

pp. e2101189118

Author(s):

Kaiwen W. Chen ◽

Benjamin Demarco ◽

Saray Ramos ◽

Rosalie Heilig ◽

Michiel Goris ◽

...

Keyword(s):

Mapk Signaling ◽

Effector Proteins ◽

Innate Immune ◽

Target Cells ◽

Caspase 8 ◽

Dependent Manner ◽

Immune Signaling ◽

Innate Immune Signaling ◽

Common Strategy

Injection of effector proteins to block host innate immune signaling is a common strategy used by many pathogenic organisms to establish an infection. For example, pathogenic Yersinia species inject the acetyltransferase YopJ into target cells to inhibit NF-κB and MAPK signaling. To counteract this, detection of YopJ activity in myeloid cells promotes the assembly of a RIPK1–caspase-8 death–inducing platform that confers antibacterial defense. While recent studies revealed that caspase-8 cleaves the pore-forming protein gasdermin D to trigger pyroptosis in macrophages, whether RIPK1 activates additional substrates downstream of caspase-8 to promote host defense is unclear. Here, we report that the related gasdermin family member gasdermin E (GSDME) is activated upon detection of YopJ activity in a RIPK1 kinase–dependent manner. Specifically, GSDME promotes neutrophil pyroptosis and IL-1β release, which is critical for anti-Yersinia defense. During in vivo infection, IL-1β neutralization increases bacterial burden in wild-type but not Gsdme-deficient mice. Thus, our study establishes GSDME as an important mediator that counteracts pathogen blockade of innate immune signaling.

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An orthotopic glioblastoma animal model suitable for high-throughput screenings

Neuro-Oncology ◽

10.1093/neuonc/noy071 ◽

2018 ◽

Vol 20 (11) ◽

pp. 1475-1484 ◽

Cited By ~ 7

Author(s):

Linda Pudelko ◽

Steven Edwards ◽

Mirela Balan ◽

Daniel Nyqvist ◽

Jonathan Al-Saadi ◽

...

Keyword(s):

Drug Discovery ◽

High Throughput ◽

Large Scale ◽

Light Sheet ◽

Time Lapse ◽

Zebrafish Model ◽

Light Sheet Microscopy ◽

Disease Biology ◽

Vertebrate Model

Abstract Background Glioblastoma (GBM) is an aggressive form of brain cancer with poor prognosis. Although murine animal models have given valuable insights into the GBM disease biology, they cannot be used in high-throughput screens to identify and profile novel therapies. The only vertebrate model suitable for large-scale screens, the zebrafish, has proven to faithfully recapitulate biology and pathology of human malignancies, and clinically relevant orthotopic zebrafish models have been developed. However, currently available GBM orthotopic zebrafish models do not support high-throughput drug discovery screens. Methods We transplanted both GBM cell lines as well as patient-derived material into zebrafish blastulas. We followed the behavior of the transplants with time-lapse microscopy and real-time in vivo light-sheet microscopy. Results We found that GBM material transplanted into zebrafish blastomeres robustly migrated into the developing nervous system, establishing an orthotopic intracranial tumor already 24 hours after transplantation. Detailed analysis revealed that our model faithfully recapitulates the human disease. Conclusion We have developed a robust, fast, and automatable transplantation assay to establish orthotopic GBM tumors in zebrafish. In contrast to currently available orthotopic zebrafish models, our approach does not require technically challenging intracranial transplantation of single embryos. Our improved zebrafish model enables transplantation of thousands of embryos per hour, thus providing an orthotopic vertebrate GBM model for direct application in drug discovery screens.

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