MicroRNA regulation of type 2 innate lymphoid cell homeostasis and function in allergic inflammation

MicroRNAs (miRNAs) exert powerful effects on immunity through coordinate regulation of multiple target genes in a wide variety of cells. Type 2 innate lymphoid cells (ILC2s) are tissue sentinel mediators of allergic inflammation. We established the physiological requirements for miRNAs in ILC2 homeostasis and immune function and compared the global miRNA repertoire of resting and activated ILC2s and T helper type 2 (TH2) cells. After exposure to the natural allergen papain, mice selectively lacking the miR-17∼92 cluster in ILC2s displayed reduced lung inflammation. Moreover, miR-17∼92–deficient ILC2s exhibited defective growth and cytokine expression in response to IL-33 and thymic stromal lymphopoietin in vitro. The miR-17∼92 cluster member miR-19a promoted IL-13 and IL-5 production and inhibited expression of several targets, including SOCS1 and A20, signaling inhibitors that limit IL-13 and IL-5 production. These findings establish miRNAs as important regulators of ILC2 biology, reveal overlapping but nonidentical miRNA-regulated gene expression networks in ILC2s and TH2 cells, and reinforce the therapeutic potential of targeting miR-19 to alleviate pathogenic allergic responses.

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A Gata3 enhancer necessary for ILC2 development and function

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2106311118 ◽

2021 ◽

Vol 118 (32) ◽

pp. e2106311118

Author(s):

Darshan N. Kasal ◽

Zhitao Liang ◽

Maile K. Hollinger ◽

Crystal Y. O’Leary ◽

Wioletta Lisicka ◽

...

Keyword(s):

Inflammatory Responses ◽

Lymphoid Cells ◽

Th2 Cells ◽

Regulatory Pathways ◽

Th2 Cell ◽

Gata3 Expression ◽

Gene Regulatory ◽

High Level ◽

And Function

The type 2 helper effector program is driven by the master transcription factor GATA3 and can be expressed by subsets of both innate lymphoid cells (ILCs) and adaptive CD4+ T helper (Th) cells. While ILC2s and Th2 cells acquire their type 2 differentiation program under very different contexts, the distinct regulatory mechanisms governing this common program are only partially understood. Here we show that the differentiation of ILC2s, and their concomitant high level of GATA3 expression, are controlled by a Gata3 enhancer, Gata3 +674/762, that plays only a minimal role in Th2 cell differentiation. Mice lacking this enhancer exhibited defects in several but not all type 2 inflammatory responses, depending on the respective degree of ILC2 and Th2 cell involvement. Our study provides molecular insights into the different gene regulatory pathways leading to the acquisition of the GATA3-driven type 2 helper effector program in innate and adaptive lymphocytes.

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ILC2s regulate adaptive Th2 cell functions via PD-L1 checkpoint control

Journal of Experimental Medicine ◽

10.1084/jem.20170051 ◽

2017 ◽

Vol 214 (9) ◽

pp. 2507-2521 ◽

Cited By ~ 54

Author(s):

Christian Schwartz ◽

Adnan R. Khan ◽

Achilleas Floudas ◽

Sean P. Saunders ◽

Emily Hams ◽

...

Keyword(s):

T Cell Response ◽

Lymphoid Cells ◽

Th2 Cells ◽

Nippostrongylus Brasiliensis ◽

Checkpoint Control ◽

T Helper ◽

Inhibitor Molecule ◽

Cell Functions

Group 2 innate lymphoid cells (ILC2s) are important effector cells driving the initiation of type 2 immune responses leading to adaptive T helper 2 (Th2) immunity. Here we show that ILC2s dynamically express the checkpoint inhibitor molecule PD-L1 during type 2 pulmonary responses. Surprisingly, PD-L1:PD-1 interaction between ILC2s and CD4+ T cells did not inhibit the T cell response, but PD-L1–expressing ILC2s stimulated increased expression of GATA3 and production of IL-13 by Th2 cells both in vitro and in vivo. Conditional deletion of PD-L1 on ILC2s impaired early Th2 polarization and cytokine production, leading to delayed worm expulsion during infection with the gastrointestinal helminth Nippostrongylus brasiliensis. Our results identify a novel PD-L1–controlled mechanism for type 2 polarization, with ILC2s mediating an innate checkpoint to control adaptive T helper responses, which has important implications for the treatment of type 2 inflammation.

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IL-9–mediated survival of type 2 innate lymphoid cells promotes damage control in helminth-induced lung inflammation

Journal of Experimental Medicine ◽

10.1084/jem.20130071 ◽

2013 ◽

Vol 210 (13) ◽

pp. 2951-2965 ◽

Cited By ~ 239

Author(s):

Jan-Eric Turner ◽

Peter J. Morrison ◽

Christoph Wilhelm ◽

Mark Wilson ◽

Helena Ahlfors ◽

...

Keyword(s):

Lung Inflammation ◽

Damage Control ◽

Recovery Phase ◽

Innate Lymphoid Cells ◽

Lymphoid Cells ◽

Th2 Cells ◽

Nippostrongylus Brasiliensis

IL-9 fate reporter mice established type 2 innate lymphoid cells (ILC2s) as major producers of this cytokine in vivo. Here we focus on the role of IL-9 and ILC2s during the lung stage of infection with Nippostrongylus brasiliensis, which results in substantial tissue damage. IL-9 receptor (IL-9R)–deficient mice displayed reduced numbers of ILC2s in the lung after infection, resulting in impaired IL-5, IL-13, and amphiregulin levels, despite undiminished numbers of Th2 cells. As a consequence, the restoration of tissue integrity and lung function was strongly impaired in the absence of IL-9 signaling. ILC2s, in contrast to Th2 cells, expressed high levels of the IL-9R, and IL-9 signaling was crucial for the survival of activated ILC2s in vitro. Furthermore, ILC2s in the lungs of infected mice required the IL-9R to up-regulate the antiapoptotic protein BCL-3 in vivo. This highlights a unique role for IL-9 as an autocrine amplifier of ILC2 function, promoting tissue repair in the recovery phase after helminth-induced lung inflammation.

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Leukotrienes provide an NFAT-dependent signal that synergizes with IL-33 to activate ILC2s

Journal of Experimental Medicine ◽

10.1084/jem.20161274 ◽

2016 ◽

Vol 214 (1) ◽

pp. 27-37 ◽

Cited By ~ 66

Author(s):

Jakob von Moltke ◽

Claire E. O’Leary ◽

Nora A. Barrett ◽

Yoshihide Kanaoka ◽

K. Frank Austen ◽

...

Keyword(s):

T Cells ◽

Allergic Inflammation ◽

Primary Source ◽

Cell Receptor ◽

Lymphoid Cells ◽

Th2 Cells ◽

Nuclear Factor ◽

Activated T Cells ◽

Deficient Mice

Group 2 innate lymphoid cells (ILC2s) and type 2 helper T cells (Th2 cells) are the primary source of interleukin 5 (IL-5) and IL-13 during type 2 (allergic) inflammation in the lung. In Th2 cells, T cell receptor (TCR) signaling activates the transcription factors nuclear factor of activated T cells (NFAT), nuclear factor κB (NF-κB), and activator protein 1 (AP-1) to induce type 2 cytokines. ILC2s lack a TCR and respond instead to locally produced cytokines such as IL-33. Although IL-33 induces AP-1 and NF-κB, NFAT signaling has not been described in ILC2s. In this study, we report a nonredundant NFAT-dependent role for lipid-derived leukotrienes (LTs) in the activation of lung ILC2s. Using cytokine reporter and LT-deficient mice, we find that complete disruption of LT signaling markedly diminishes ILC2 activation and downstream responses during type 2 inflammation. Type 2 responses are equivalently attenuated in IL-33– and LT-deficient mice, and optimal ILC2 activation reflects potent synergy between these pathways. These findings expand our understanding of ILC2 regulation and may have important implications for the treatment of airways disease.

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ICAM-1 controls development and function of ILC2

Journal of Experimental Medicine ◽

10.1084/jem.20172359 ◽

2018 ◽

Vol 215 (8) ◽

pp. 2157-2174 ◽

Cited By ~ 24

Author(s):

Ai-Hua Lei ◽

Qiang Xiao ◽

Gao-Yu Liu ◽

Kun Shi ◽

Qiong Yang ◽

...

Keyword(s):

Airway Inflammation ◽

Allergic Airway Inflammation ◽

Lymphoid Cells ◽

Peripheral Tissues ◽

Type 2 Cytokines ◽

Functionally Impaired ◽

Group 2 ◽

And Function

Group 2 innate lymphoid cells (ILC2s) are emerging as key players in the pathogenesis of allergic airway inflammation. The mechanisms regulating ILC2, however, are not fully understood. Here, we found that ICAM-1 is required for the development and function of ILC2. ICAM-1–deficient (ICAM-1−/−) mice displayed significantly lower levels of ILC2s in the bone marrow and peripheral tissues than wild-type controls. CLP transfer and in vitro culture assays revealed that the regulation of ILC2 by ICAM-1 is cell intrinsic. Furthermore, ILC2s from ICAM-1−/− mice were functionally impaired, as indicated by the diminished production of type-2 cytokines in response to IL-33 challenge. The reduction in lung ILC2s caused a clear remission of airway inflammation in ICAM-1−/− mice after administration of papain or Alternaria alternata. We further demonstrate that ILC2 defects caused by ICAM-1 deficiency are due to ERK signaling-dependent down-regulation of GATA3 protein. Collectively, these observations identify ICAM-1 as a novel regulator of ILC2.

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The Role of PPAR-γ in Allergic Disease

Current Allergy and Asthma Reports ◽

10.1007/s11882-021-01022-x ◽

2021 ◽

Vol 21 (11) ◽

Author(s):

Julian M. Stark ◽

Jonathan M. Coquet ◽

Christopher A. Tibbitt

Keyword(s):

Gene Expression ◽

Epithelial Cells ◽

Immune Responses ◽

Allergic Disease ◽

Allergic Inflammation ◽

Allergic Diseases ◽

Lymphoid Cells ◽

Th2 Cells ◽

Ppar Γ

Abstract Purpose of Review The incidence of allergic diseases such as asthma, rhinitis and atopic dermatitis has risen at an alarming rate over the last century. Thus, there is a clear need to understand the critical factors that drive such pathologic immune responses. Peroxisome proliferator-activated receptor-γ (PPAR-γ) is a nuclear receptor that has emerged as an important regulator of multiple cell types involved in the inflammatory response to allergens; from airway epithelial cells to T Helper (TH) cells. Recent Findings Initial studies suggested that agonists of PPAR-γ could be employed to temper allergic inflammation, suppressing pro-inflammatory gene expression programs in epithelial cells. Several lines of work now suggest that PPAR-γ plays an essential in promoting ‘type 2’ immune responses that are typically associated with allergic disease. PPAR-γ has been found to promote the functions of TH2 cells, type 2 innate lymphoid cells, M2 macrophages and dendritic cells, regulating lipid metabolism and directly inducing effector gene expression. Moreover, preclinical models of allergy in gene-targeted mice have increasingly implicated PPAR-γ in driving allergic inflammation. Summary Herein, we highlight the contrasting roles of PPAR-γ in allergic inflammation and hypothesize that the availability of environmental ligands for PPAR-γ may be at the heart of the rise in allergic diseases worldwide.

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Lysophosphatidic Acid Regulates the Differentiation of Th2 Cells and Its Antagonist Suppresses Allergic Airway Inflammation

International Archives of Allergy and Immunology ◽

10.1159/000509804 ◽

2020 ◽

Vol 182 (1) ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Mayo Kondo ◽

Toshifumi Tezuka ◽

Hirohisa Ogawa ◽

Kazuya Koyama ◽

Hiroki Bando ◽

...

Keyword(s):

Airway Inflammation ◽

Lysophosphatidic Acid ◽

Therapeutic Potential ◽

Allergic Inflammation ◽

Allergic Airway Inflammation ◽

Th2 Cells ◽

Nasal Administration ◽

Lpa Receptor

Background: Lysophosphatidic acid (LPA), a prototypic member of a large family of lysophospholipids, has been recently shown to play a role in immune responses to respiratory diseases. The involvement of LPA in allergic airway inflammation has been reported, but the mechanism remains unclear. Object: We analyzed the biological activity of LPA in vitro and in vivo and investigated its role in allergic inflammation in mice using an LPA receptor 2 (LPA2) antagonist. Methods: We used a murine model with acute allergic inflammation, in which mice are sensitized and challenged with house dust mite, and analyzed airway hyperresponsiveness (AHR), pathological findings, Th2 cytokines, and IL-33 in bronchoalveolar lavage fluid (BALF) and lung homogenates. The effect of LPA on Th2 differentiation and cytokine production was examined in vitro using naive CD4+ T cells isolated from splenocytes. We also investigated in vivo the effects of LPA on intranasal administration in mice. Results: The LPA2 antagonist suppressed the increase of AHR, the number of total cells, and eosinophils in BALF and lung tissue. It also decreased the production of IL-13 in BALF and IL-33 and CCL2 in the lung. LPA promoted Th2 cell differentiation and IL-13 production by Th2 cells in vitro. Nasal administration of LPA significantly increased the number of total cells and IL-13 in BALF via regulating the production of IL-33 and CCL-2-derived infiltrating macrophages. Conclusion: These findings suggest that LPA plays an important role in allergic airway inflammation and that the blockade of LPA2 might have therapeutic potential for bronchial asthma.

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Pulmonary type-2 innate lymphoid cells in paediatric severe asthma: phenotype and response to steroids

European Respiratory Journal ◽

10.1183/13993003.01809-2018 ◽

2019 ◽

Vol 54 (2) ◽

pp. 1801809 ◽

Cited By ~ 11

Author(s):

Prasad Nagakumar ◽

Franz Puttur ◽

Lisa G. Gregory ◽

Laura Denney ◽

Louise Fleming ◽

...

Keyword(s):

Symptom Control ◽

Innate Lymphoid Cells ◽

Lymphoid Cells ◽

Th2 Cells ◽

Poor Control ◽

Inhaled Steroids ◽

Elevated Type

Children with severe therapy-resistant asthma (STRA) have poor control despite maximal treatment, while those with difficult asthma (DA) have poor control from failure to implement basic management, including adherence to therapy. Although recognised as clinically distinct, the airway molecular phenotype, including the role of innate lymphoid cells (ILCs) and their response to steroids in DA and STRA is unknown.Immunophenotyping of sputum and blood ILCs and T-cells from STRA, DA and non-asthmatic controls was undertaken. Leukocytes were analysed longitudinally pre- and post-intramuscular triamcinolone in children with STRA. Cultured ILCs were evaluated to assess steroid responsiveness in vitro.Airway eosinophils, type 2 T-helper (Th2) cells and ILC2s were significantly higher in STRA patients compared to DA and disease controls, while IL-17+ lymphoid cells were similar. ILC2s and Th2 cells were significantly reduced in vivo following intramuscular triamcinolone and in vitro with steroids. Furthermore, asthma attacks and symptoms reduced after systemic steroids despite persistence of steroid-resistant IL-17+ cells and eosinophils.Paediatric STRA and DA have distinct airway molecular phenotypes with STRA characterised by elevated type-2 cells. Systemic corticosteroids, but not maintenance inhaled steroids resulted in improved symptom control and exacerbations concomitant with a reduction in functional ILC2s despite persistently elevated IL-17+ lymphoid cells.

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Apigenin Alleviates Renal Fibroblast Activation through AMPK and ERK Signaling Pathways In Vitro

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666200320140908 ◽

2020 ◽

Vol 21 (11) ◽

pp. 1107-1118

Author(s):

Ningning Li ◽

Zhan Wang ◽

Tao Sun ◽

Yanfei Lei ◽

Xianghua Liu ◽

...

Keyword(s):

Renal Fibrosis ◽

Transforming Growth Factor ◽

Therapeutic Potential ◽

Protective Role ◽

Fibroblast Proliferation ◽

Fibroblast Activation ◽

And Function ◽

Activated Fibroblasts ◽

Tgf Β1

Objective: Renal fibrosis is a common pathway leading to the progression of chronic kidney disease. Activated fibroblasts contribute remarkably to the development of renal fibrosis. Although apigenin has been demonstrated to play a protective role from fibrotic diseases, its pharmacological effect on renal fibroblast activation remains largely unknown. Materials and Methods: Here, we examined the functional role of apigenin in the activation of renal fibroblasts response to transforming growth factor (TGF)-β1 and its potential mechanisms. Cultured renal fibroblasts (NRK-49F) were exposed to apigenin (1, 5, 10 and 20 μM), followed by the stimulation of TGF-β1 (2 ng/mL) for 24 h. The markers of fibroblast activation were determined. In order to confirm the anti-fibrosis effect of apigenin, the expression of fibrosis-associated genes in renal fibroblasts was assessed. As a consequence, apigenin alleviated fibroblast proliferation and fibroblastmyofibroblast differentiation induced by TGF-β1. Result: Notably, apigenin significantly inhibited the fibrosis-associated genes expression in renal fibroblasts. Moreover, apigenin treatment significantly increased the phosphorylation of AMP-activated protein kinase (AMPK). Apigenin treatment also obviously reduced TGF-β1 induced phosphorylation of ERK1/2 but not Smad2/3, p38 and JNK MAPK in renal fibroblasts. Conclusion: In a summary, these results indicate that apigenin inhibits renal fibroblast proliferation, differentiation and function by AMPK activation and reduced ERK1/2 phosphorylation, suggesting it could be an attractive therapeutic potential for the treatment of renal fibrosis.

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Selective deletion of SHIP-1 in hematopoietic cells in mice leads to severe lung inflammation involving ILC2 cells

Scientific Reports ◽

10.1038/s41598-021-88677-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Xujun Ye ◽

Fengrui Zhang ◽

Li Zhou ◽

Yadong Wei ◽

Li Zhang ◽

...

Keyword(s):

Lung Inflammation ◽

Airway Remodeling ◽

Pulmonary Inflammation ◽

Hematopoietic Cells ◽

Cell Lineage ◽

Allergic Inflammation ◽

Cell Types ◽

Lymphoid Cells ◽

Whole Body

AbstractSrc homology 2 domain–containing inositol 5-phosphatase 1 (SHIP-1) regulates the intracellular levels of phosphotidylinositol-3, 4, 5-trisphosphate, a phosphoinositide 3–kinase (PI3K) product. Emerging evidence suggests that the PI3K pathway is involved in allergic inflammation in the lung. Germline or induced whole-body deletion of SHIP-1 in mice led to spontaneous type 2-dominated pulmonary inflammation, demonstrating that SHIP-1 is essential for lung homeostasis. However, the mechanisms by which SHIP-1 regulates lung inflammation and the responsible cell types are still unclear. Deletion of SHIP-1 selectively in B cells, T cells, dendritic cells (DC) or macrophages did not lead to spontaneous allergic inflammation in mice, suggesting that innate immune cells, particularly group 2 innate lymphoid cells (ILC2 cells) may play an important role in this process. We tested this idea using mice with deletion of SHIP-1 in the hematopoietic cell lineage and examined the changes in ILC2 cells. Conditional deletion of SHIP-1 in hematopoietic cells in Tek-Cre/SHIP-1 mice resulted in spontaneous pulmonary inflammation with features of type 2 immune responses and airway remodeling like those seen in mice with global deletion of SHIP-1. Furthermore, when compared to wild-type control mice, Tek-Cre/SHIP-1 mice displayed a significant increase in the number of IL-5/IL-13 producing ILC2 cells in the lung at baseline and after stimulation by allergen Papain. These findings provide some hints that PI3K signaling may play a role in ILC2 cell development at baseline and in response to allergen stimulation. SHIP-1 is required for maintaining lung homeostasis potentially by restraining ILC2 cells and type 2 inflammation.

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