Final Report Summary - TSLP IN ASTHMA (Human TSLP and OX40L as targets of therapeutic intervention for allergic asthma)
Home institute: University Medical Center Utrecht, Department of Pediatrics, the Netherlands
Host institute: Gent University and Flemish Institute for Biotechnology, Department of Molecular Biology Research, Gent, Belgium
Project period: 1 May 2010 - 31 August 2011
Introduction
Allergic asthma is a chronic inflammatory disease of the lungs, caused by dysregulated production of T-helper-2 (Th2) cytokines in response to aero-allergens, such as house dust mite (HDM). Results from adult animal models suggest that dendritic cells (DCs) are instructed to induce HDM-specific Th2 immunity via the release of pro-Th2 innate cytokines such as Thymic Stromal Lymphopoietin (TSLP) and interleukin-33 (IL-33) by bronchial epithelial cells and the expression of OX40L. TSLP, IL-33 and OX40L are therefore promising targets for the development of new therapies for allergic asthma.
Within this project, we studied the potential of targeting TSLP, IL33 and OX40L for intervening with the initiation and/or progression of allergic asthma in vivo by using the humanised mouse model for allergic asthma. This is a unique model enabling to particularly evaluate the effect of potential therapeutic compounds on human haematopoietic cells in an in vivo system.
Scientific results
The humanised mouse model for allergic asthma was successfully set up by reconstituting hu-SCID mice with peripheral blood mononuclear cells from house dust mite (HDM)-allergic patients. In these mice, the allergen-induced kinetics and expression levels of the TSLP-OX40L and IL-33-ST2-OX40L axis were studied (objective 1). Moderate TSLP levels and high DC OX40L levels were documented. The expression levels of (mouse) TSLP and other HDM induced epithelial cytokies such as IL-33 and IL1b were highly age-dependent with peak levels at postnatal day 14 (PND14). Like TSLP, IL-33 is well-known for its Th2 driving educational role on DCs. The finding that IL-33 plays a much more prominent role in infant mice compared to adult mice is of important clinical relevance since sensitisation to HDM in human usually takes place at young age. We therefore decided to extend our studies of the TSLP-OX40L axis with the IL-33-ST2-OX40L axis. For this purpose, we adjusted the running HDM model for adult wild type mice to neonatal (PND3) and infant (PND14) mice.
We next studied if and how TSLP/IL-33 influences the inititiation and progression of airway inflammation (objective 2). In each of the models, we identified the main cellular sources of TSLP (epithelial cells) and IL-33 (epithelial cells and macrophages). Besides high IL-33, young mice show high expression levels of the IL-33 receptor T1/ST2. Highest expression levels were found on CD11b+ lung DC and innate lymphoid cells with again, highly significant differences between the different age groups. Both in vivo and in vitro assays showed that increasing concentrations of recombinant IL-33 had a much more pronounced effect on DC phenotype and function in PND14 mice than in adult mice. Dendritic cells of PND14 mice and exposed to high levels of IL33 showed more distinct Th2 deviating characteristics than adult DC, including much higher expression levels of OX40L (objective 2ii).
Studies with blocking anti-OX40L nanobodies in the humanised asthma model showed a significant effect of anti-OX40L on all cardinal features of allergic airway inflammation (objective 3). We also performed blocking studies in PND3, PND14 and adult mice, using soluble ST2-Receptor (sST2R) in the sensitisation and challenge phase of the HDM protocol. These experiments showed a spectacular protective effect of sST2R in infant mice where only a mild effect was seen in adult mice.
We concluded from these experiments that antibodies blocking the IL33-ST2-OX40L and/or the TSLP-OX40L pathways have potential as a preventive and therapeutic application for allergic asthma. By testing the compounds in a humanised mouse model for allergic asthma we were the first to provide proof-of-concept in the human immune system in vivo. In addition, we gained important insight into the working mechanisms of the compounds and we identified an age / developmental window during which the compounds are increased effective.
Scientific output and transfer of knowledge activities:
- Two scientific papers are currently in preparation and will soon be submitted.
- Scientific data were presented at several national and international scientific congresses, including the annual congress of the European Respiratory Society and annual congresses of the European Academy of Allergy and Clinical Immunology.
- Transfer of knowledge was accelerated through involvement in networks like the Eureka Institute for Translational Medicine, networks within the Flemish Institute for Biotechnology and Gent University and specific allergy / pulmonology research and drug development networks, including working groups of the European Respiratory Society, the Utrecht Allergy Consortium and the Global Allergy and Asthma European Network (GA2LEN).
Socio-economic impact
Asthma is a significant source of morbidity and mortality worldwide and starts most often during early childhood. Because of the high prevalence and chronic nature of asthma, the economic costs associated with asthma rank as one of the highest among chronic diseases. Novel forms of prevention and/or cure for allergic asthma are urgently needed. Our data on the effect of anti-OX40L and sST2R in a humanised mouse model and in a neonatal / infant mouse model for allergic asthma currently contribute to important go-no go decisions to further advance this preventive / therapeutic strategy to the (paediatric) clinics.
Training objectives
All training objectives of the Marie Curie fellowship have been met. The project enabled me to learn all the ins and outs of multiple mouse models for allergic asthma and the accompanying techniques. I set up a new neonatal and infant model for HDM induced asthma. I followed several courses, amongst which a microscopy course and flowcytometry course and weekly attended research meetings and symposia. I supervised three PhD students and I was involved in several networks on translational medicine. Importantly, the data obtained during this project were used for the successful application for a follow-up grant (Veni-grant, Dutch scientific organisation).
Conclusion
All research and training objectives of the proposal have been met. Scientific data have been broadly distributed at scientific meetings and within scientific networks. We expect at least two high impact publications to come out of this project.
This Marie Curie Intra European Fellowship provided me of an opportunity to learn a broad range of research techniques and to develop conceptual and analytical skills in a dynamic and challenging environment. I successfully applied for a prestigious follow up grant. This grant will allow me to further develop my translational research line directed at the immunopathology of allergic asthma in young children within my home institute and to continue collaboration with Prof. B. Lambrecht and his group.
Host institute: Gent University and Flemish Institute for Biotechnology, Department of Molecular Biology Research, Gent, Belgium
Project period: 1 May 2010 - 31 August 2011
Introduction
Allergic asthma is a chronic inflammatory disease of the lungs, caused by dysregulated production of T-helper-2 (Th2) cytokines in response to aero-allergens, such as house dust mite (HDM). Results from adult animal models suggest that dendritic cells (DCs) are instructed to induce HDM-specific Th2 immunity via the release of pro-Th2 innate cytokines such as Thymic Stromal Lymphopoietin (TSLP) and interleukin-33 (IL-33) by bronchial epithelial cells and the expression of OX40L. TSLP, IL-33 and OX40L are therefore promising targets for the development of new therapies for allergic asthma.
Within this project, we studied the potential of targeting TSLP, IL33 and OX40L for intervening with the initiation and/or progression of allergic asthma in vivo by using the humanised mouse model for allergic asthma. This is a unique model enabling to particularly evaluate the effect of potential therapeutic compounds on human haematopoietic cells in an in vivo system.
Scientific results
The humanised mouse model for allergic asthma was successfully set up by reconstituting hu-SCID mice with peripheral blood mononuclear cells from house dust mite (HDM)-allergic patients. In these mice, the allergen-induced kinetics and expression levels of the TSLP-OX40L and IL-33-ST2-OX40L axis were studied (objective 1). Moderate TSLP levels and high DC OX40L levels were documented. The expression levels of (mouse) TSLP and other HDM induced epithelial cytokies such as IL-33 and IL1b were highly age-dependent with peak levels at postnatal day 14 (PND14). Like TSLP, IL-33 is well-known for its Th2 driving educational role on DCs. The finding that IL-33 plays a much more prominent role in infant mice compared to adult mice is of important clinical relevance since sensitisation to HDM in human usually takes place at young age. We therefore decided to extend our studies of the TSLP-OX40L axis with the IL-33-ST2-OX40L axis. For this purpose, we adjusted the running HDM model for adult wild type mice to neonatal (PND3) and infant (PND14) mice.
We next studied if and how TSLP/IL-33 influences the inititiation and progression of airway inflammation (objective 2). In each of the models, we identified the main cellular sources of TSLP (epithelial cells) and IL-33 (epithelial cells and macrophages). Besides high IL-33, young mice show high expression levels of the IL-33 receptor T1/ST2. Highest expression levels were found on CD11b+ lung DC and innate lymphoid cells with again, highly significant differences between the different age groups. Both in vivo and in vitro assays showed that increasing concentrations of recombinant IL-33 had a much more pronounced effect on DC phenotype and function in PND14 mice than in adult mice. Dendritic cells of PND14 mice and exposed to high levels of IL33 showed more distinct Th2 deviating characteristics than adult DC, including much higher expression levels of OX40L (objective 2ii).
Studies with blocking anti-OX40L nanobodies in the humanised asthma model showed a significant effect of anti-OX40L on all cardinal features of allergic airway inflammation (objective 3). We also performed blocking studies in PND3, PND14 and adult mice, using soluble ST2-Receptor (sST2R) in the sensitisation and challenge phase of the HDM protocol. These experiments showed a spectacular protective effect of sST2R in infant mice where only a mild effect was seen in adult mice.
We concluded from these experiments that antibodies blocking the IL33-ST2-OX40L and/or the TSLP-OX40L pathways have potential as a preventive and therapeutic application for allergic asthma. By testing the compounds in a humanised mouse model for allergic asthma we were the first to provide proof-of-concept in the human immune system in vivo. In addition, we gained important insight into the working mechanisms of the compounds and we identified an age / developmental window during which the compounds are increased effective.
Scientific output and transfer of knowledge activities:
- Two scientific papers are currently in preparation and will soon be submitted.
- Scientific data were presented at several national and international scientific congresses, including the annual congress of the European Respiratory Society and annual congresses of the European Academy of Allergy and Clinical Immunology.
- Transfer of knowledge was accelerated through involvement in networks like the Eureka Institute for Translational Medicine, networks within the Flemish Institute for Biotechnology and Gent University and specific allergy / pulmonology research and drug development networks, including working groups of the European Respiratory Society, the Utrecht Allergy Consortium and the Global Allergy and Asthma European Network (GA2LEN).
Socio-economic impact
Asthma is a significant source of morbidity and mortality worldwide and starts most often during early childhood. Because of the high prevalence and chronic nature of asthma, the economic costs associated with asthma rank as one of the highest among chronic diseases. Novel forms of prevention and/or cure for allergic asthma are urgently needed. Our data on the effect of anti-OX40L and sST2R in a humanised mouse model and in a neonatal / infant mouse model for allergic asthma currently contribute to important go-no go decisions to further advance this preventive / therapeutic strategy to the (paediatric) clinics.
Training objectives
All training objectives of the Marie Curie fellowship have been met. The project enabled me to learn all the ins and outs of multiple mouse models for allergic asthma and the accompanying techniques. I set up a new neonatal and infant model for HDM induced asthma. I followed several courses, amongst which a microscopy course and flowcytometry course and weekly attended research meetings and symposia. I supervised three PhD students and I was involved in several networks on translational medicine. Importantly, the data obtained during this project were used for the successful application for a follow-up grant (Veni-grant, Dutch scientific organisation).
Conclusion
All research and training objectives of the proposal have been met. Scientific data have been broadly distributed at scientific meetings and within scientific networks. We expect at least two high impact publications to come out of this project.
This Marie Curie Intra European Fellowship provided me of an opportunity to learn a broad range of research techniques and to develop conceptual and analytical skills in a dynamic and challenging environment. I successfully applied for a prestigious follow up grant. This grant will allow me to further develop my translational research line directed at the immunopathology of allergic asthma in young children within my home institute and to continue collaboration with Prof. B. Lambrecht and his group.