introduction
DESCRIPTION
Group 2 : Animal models for mast cell research Trainer : Katerina Tiligada. Introduction. In vivo animal models for Mast cell research: Guinea Pig Humanized Mice Zebrafish. Aim : comparison of established versus new in vivo models . - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/1.jpg)
Introduction
In vivo animal models for Mast cell research:1. Guinea Pig2. Humanized Mice3. Zebrafish
Aim: comparison of established versus new in vivo models
Group 2: Animal models for mast cell researchTrainer: Katerina Tiligada
![Page 2: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/2.jpg)
Aim: to evaluate a combination treatment in an animal model of early allergic reaction in the lung by using the established guinea pig model
Background: insufficiency of mouse models due to differences between human and mice MC distribution, mediator release and phenotype
![Page 3: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/3.jpg)
P: Pyrilamine - H1 antagonistM: Montelukast - cysLT inhibitorI: Indomethacin – COX inhibitor - NSAID
Treatment with pyrilamine in combination with montelukast or/and indomethacin reduced EAR
![Page 4: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/4.jpg)
Summary
The sensitized guinea pig is a well accepted and validated model for the study of pharmacological approaches related to
allergy treatment
Limitations of the study
Methodological shortcomings (e.g. no dose-response-curve, no justification for the selection of drugs to be investigated)
Limited novel information
![Page 5: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/5.jpg)
Background: lack of mice model which reflects human allergy response
Aim: To generate a humanized mouse strain that develops human granulocytes and mast cells
![Page 6: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/6.jpg)
Differentiation of myeloid and lymphoid cells inhu-HSC NOG IL-3/GM-Tg mice
![Page 7: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/7.jpg)
Differentiation of myeloid and lymphoid cells inhu-HSC NOG IL-3/GM-Tg mice
![Page 8: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/8.jpg)
Extravasation of Evans blue dye in the skin of hu-HSC NOG IL-3/GM-Tg mice
![Page 9: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/9.jpg)
Summary
The first human IL-3 and GM-CSF producing mice able to develop human granulocytes and mast cells
A new model which enables the research on human cell in vivo
Limitations of the study
Lack of cell-cell interactions of the same species origin
Mast cells can differentiate depending on the (micro)environment
![Page 10: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/10.jpg)
• Zebrafish is a robust model for studying vertebrate hematopoiesis• Presence of mast cells, basophils and eosinophils• Orthologs of toll-like receptors (TLRs) and myd88• Structural and functional similarities between zebrafish and mammalian MCs
Aim: Investigation of the FcεRI-mediated MC response upon stimulation
![Page 11: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/11.jpg)
Release of tryptase is induced by C48/80 and A. salmonicida while being inhibited by ketotifen
![Page 12: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/12.jpg)
Release of tryptase is induced by anti-IgE:DNP complex
![Page 13: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/13.jpg)
Summary
Zebrafish represents a potential new model for studying MC-mediated responses in vivo
Limitationsof the study
Functional studies to support the preliminary findings not conducted
Inhibition of the IgE-mediated pathway not investigated
Experimental settings are not specific for zebrafish
![Page 14: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/14.jpg)
Overall summary• The attempts of calibration & development of suitable models are
continuous. Overall, we are slowly getting closer to (patho)physiological relevance
• Functional and behavioral studies on MCs are being researched in few models, each one being suitable for a limited range of research questions/hypotheses
• No universal model is available; depending on the question to be answered, acceptable models have to be selected
Preliminary data ValidatedGuinea pig Humanized mice Zebrafish
![Page 15: Introduction](https://reader035.vdocuments.mx/reader035/viewer/2022062813/5681666b550346895dda04b9/html5/thumbnails/15.jpg)
Difficulties in in vivo studies: validation protocols; different markers, triggers, agents, etc
• Need for harmonization & standardization of the essential protocols/methodologies for validation of novel in vivo models in various species: consideration of strain, gender, age differences/variations; visibility of negative results is essential
• In vivo drug administration: consideration of strain-related differences, ligand specificity, ligand-directed signaling, threshold/baseline/placebo responses, dose-response curves, selection of the appropriate control drug
• Inter/intra species cell-cell interaction and immune responses in in vivo models (particularly concerning Tg & humanised models)
• Comparative definition of mast cell/basophil (rodent models are different from human, including MC/basophil phenotypes & behaviour): need for a (minimal) list of characteristics and comparison between species
Group 2: Animal models for mast cell researchTrainer: Katerina Tiligada
Points following discussion