Download Innate lymphoid cells: identification of their role in allergic asthma

Innate lymphoid cells: identification of their role in allergic asthma and
exacerbations upon respiratory tract infection
Department of Pulmonary Medicine, project 6
Contact information
Prof. Dr. R.W. Hendriks (Head of research department)
Telephone 010-7043700
e-mail: [email protected]
Duration
6 months
12 months
18 months
Yes/No
Yes
Yes
Yes
Available per (date)
September 2017
September 2017
September 2017
Background
Asthma is a chronic lung disease characterized by reversible airway obstruction, hyperresponsiveness
and pulmonary inflammation. Classically, asthma is thought to arise from a T helper 2 (Th2) immune
response to allergens, such as house-dust mite (HDM). Th2 cells produce vast amounts of cytokines
that induce IgE (interleukin-4; IL-4), recruit eosinophils and mast cells (IL-5 and IL-9) and cause
smooth muscle hyperreactivity and goblet cell hyperplasia (IL-13). An important aspect of asthma
that has never been adequately addressed by the Th2 paradigm is the observation that respiratory
pathogens, which can engender robust innate and/or Th1 responses, can initiate and promulgate
pulmonary inflammation and airway obstruction in asthma. Rhinovirus, RSV and influenza virus and
Mycoplasma pneumoniae bacteria are common causes of asthma exacerbations. Interestingly, a
novel non-T/non-B lymphoid cell population, named group 2 innate lymphocytes (ILC2s), producing
high amounts of IL-5 and IL-13 was recently discovered. Unlike Th2 cells, ILC2s are not antigenrestricted. ILC2s are activated by epithelial cell-derived cytokines IL-25 and IL-33 and were recently
shown to accumulate in the lung after influenza infection in mice, thereby inducing hyperreactivity
and promoting tissue repair, dependent on the epidermal growth factor-family member
amphiregulin. In human, ILC2s were reported to be enriched in nasal polyps of chronic rhinosinusitis
patients.
This project is based on our recent finding that ILC2s are involved in allergic airway
inflammation in mice. Intranasal administration of IL-25 or IL-33 induced an asthma phenotype and
the accumulation in the lungs of ILC2s producing large amounts of IL-5 and IL-13. Importantly, in
HDM or ovalbumin-induced asthma the contribution of ILC2s to the total population of IL-5+ or IL-13+
cells in the lung was in the same range as for classical Th2 cells. We also found increased ILC2s in
bronchoalveolar lavage at day 18 after infection with H3N2 influenza virus in mice. Using Affimetrix
gene chip expression profiling of total lungs during influenza infection, we observed induction of IL13, IL-33R and amphiregulin. Interestingly, amphiregulin has the capacity to upregulate mucin
expression and in increased in sputum of chidren with asthma.
Research
The findings described above provide a solid basis to test the hypothesis that ILC2 play an essential
role in asthma pathogenesis and may comprise the long sought for link between respiratory tract
infection and asthma exacerbation.
In this project, we will investigate in a HDM-induced allergic airway inflammation model in
mice (1) how ILC2s collaborate with Th2 cells, using cell transfer approaches and confocal microscopy
and (2) how an influenza virus infection affects ILC2 activity and asthma symptoms. In these
experiments we will determine the effects of treatment with antibodies to the IL-25 and IL-33
receptors and determine genome-wide expression profiles of ILC2s. (3) We also plan to investigate
whether ILC2 are increased in bronchial mucosal biopsies or peripheral blood of asthma patients.
Collectively, these experiments address the involvement of ILC2s in asthma and exacerbations and
may result in the identification of new therapeutic targets or biomarkers.
Finally, we recently generated epigenomic profiles of in vivo activated ILC2s and Th2 cells
from mice with allergic airway inflammation and found largely overlapping patterns of H3K4Me2 at
loci controlling type-2 immunity. The few Th2-specific gene regulatory elements (GREs)
predominantly regulate genes implicated in T cell receptor signaling and co-stimulation. The
surprisingly richer ILC2-specific active epigenome consists of distal GREs and novel superenhancers
near genes involved in allergy, metabolism, immune signaling and cellular plasticity. Moreover,
transcription factor binding landscapes at GREs were markedly different between ILC2s and Th2 cells.
Importantly, shared and ILC2-specific - but few Th2-specific - GREs reside in asthma-associated loci in
human and murine cells, prioritizing GREs potentially relevant for asthma and supporting a
pathogenic role for ILC2s in human asthma.
Master of Science projects (6/12/18 months)
Students interested in fundamental/translational research who would like to support us in gaining
more insight into the different aspects of asthma exacerbation and/or physiological relevance of the
newly identified population of innate lymphocytes are kindly invited to participate. Master students
interested in a 12-month or 18-month Master of Science project can take an animal course (Art. 9).
As a Master student, you will be working at the Department of Pulmonary Medicine on the research
projects outlined above, together with a post-doc and the head of the research department (see
‘Contact details’). As these research projects comprise multiple research (sub)questions, you will be
focusing during your project mostly on a well-defined part of the research line.
As the project demands an experimental approach that is both fundamental and diseaserelated, you will have the opportunity to learn and use a whole variety of techniques, including
techniques for RNA analysis (RT-PCR), protein analysis, ex vivo analysis of B, T and innate
lymphocytes using advanced multi-color flow cytometry (staining of extracellular markers,
intracellular molecules such as cytokines, etcetera), confocal immunofluorescence microscopy,
immunohistochemistry on lymphoid organs and lungs and quantification using different assays
(ELISA), T cell culture systems, and induced disease models, in particular HDM-induced allergic
asthma and lung influenza virus infection. Moreover, the project may include molecular analyses in
the field of epigenetics and bioinformatics, both on human and on mouse ILC2 or Th2 cells.
We have obtained mouse models to specifically identify ILC2 using a YFP reporter through a
collaboration with Dr. J. Fehling (Ulm, Germany) or to specifically delete ILC2 through a collaboration
with prof. A. McKenzie (Cambridge, UK). Human ILC2 work is done in collaboration with prof. J. di
Santo (Paris, France).
Master students interested in a 12-month (or 18-month) Master of Science project may take
an animal course (Art. 9). As the post-doc on the project will start early next year, this research h
project will be available from September 2017 onwards.