Role of TNF receptor 2 on Pulmonary Group 2 Innate Lymphoid Cells

Abstract
The long-term goal of this project is to develop better therapies for respiratory inflammation and allergic
asthma. Group 2 innate lymphoid cells (ILC2) are a recently identified cell population producing type 2
cytokines in response to a growing number of environmental signals and epithelial cell-derived cytokines.
Studies show increased ILC2 activity in asthma and many widespread diseases, as ILC2s are sufficient to
induce airway inflammation independent of adaptive immunity in mice. The proposed research plan is
motivated by recent new observations from our laboratory and others that the TNF/TNFR2 axis controls ILC2-
dependent airway inflammation (Cell Report 2019, J Allergy Clin Immunol. 2020). High levels of TNF are
found in the lungs of asthmatic patients, however anti-TNF therapy is generally associated with systemic
toxicity due to the existence of two distinct functionally different receptors for TNF: TNFR1 and TNFR2. Our
results suggest that TNF enhanced the secretion of ILC2 effector cytokines IL-5 and IL-13 and increased
survival via TNFR2 signaling, leading to airway inflammation. However, how the TNF/TNFR2 axis
mechanistically affects ILC2s and subsequent development of airway inflammation remains to be explored.
Based on our data, we hypothesize that blocking TNFR2 on ILC2s induces an immunoregulatory phenotype
fueling on a distinct metabolic source, together favoring the reduction of AHR. In Specific Aim 1 (SA1), we
have designed several approaches to characterize the effects of TNF on ILC2 effector functions and lung
inflammation. Our preliminary data suggest that TNFR2 is heterogeneously expressed on activated ILC2s. We
will therefore characterize the transcription factors driving the effects of TNF in ILC2s using a combination of
single cell genomic and transcriptomic analysis. Furthermore, data from our laboratory and others suggest that
metabolic processes in ILC2s are dependent on the generation of energy from fatty acid oxidation (FAO) and
oxidative phosphorylation. Interestingly our results clearly show a metabolic shift towards glycolysis in TNFR2-/-
ILC2s. Based on these results we intend to assess glycolysis and FAO mechanisms in WT and TNFR2-/- ILC2s
in SA2. Finally, we previously showed that human ILC2s express TNFR2 and humanized ILC2 mice developed
TNFR2-dependent AHR in response to TNF. Therefore, we intend to assess in the SA3 the relevance of our
findings in asthmatic patients. We will collect lung and blood ILC2s from carefully selected cohorts of
mild/moderate, severe asthmatics and healthy donors and correlate the levels of TNF in the BAL to the
numbers of ILC2s/expression of TNFR2, as well as monitor other cells that express TNFR2. These studies,
based on strong preliminary data, will focus on developing novel therapy for allergic asthma. In order to
achieve these results we have assembled a team including leading experts in lung biology and the chief of
clinical pulmonology to complement our extensive experience in pre-clinical models.

Grant Number: 5R01HL159804-04
NIH Institute/Center: NIH
Principal Investigator: OMID AKBARI