Innate lymphoid cells Jenny Mjösberg

Innate lymphoid cells (ILCs) are recently described microenvironment. However, they can regulate populations of lymphocytes that lack rearranged tissue homeostasis, inflammation and repair at antigen-specific receptors. The ILC family has been both mucosal and non-mucosal sites, including the divided into three main subsets — ILC1, ILC2 and intestine, lungs and skin, as well as in adipose and ILC3 — and also includes natural killer (NK) cells lymphoid tissues1. ILC effector functions are mainly and lymphoid tissue-inducer (LTi) cells. ILCs are mediated through cytokine secretion and through increasingly appreciated to have important immune direct cell–cell interactions with stromal cells and functions at mucosal surfaces, where they respond other immune cells. This Poster summarizes some of to signals they receive from other cells in the tissue the key features of ILCs in homeostasis and disease.

Bone marrow ILC development Skin or fetal liver CLP Much work has been done to define the Homeostasis and Psoriasis tissue repair TCF1, ontogeny of mouse ILCs; however, Damage OVA, papain, HDM, EOMES, NFIL3, GATA3, human ILC development remains largely Bacteria calcipotriol or LPS ID2, TOX ID2, uncharacterized. ILCs originate from a Keratinocyte NFIL3 IL-7 EILP common lymphoid progenitor (CLP), NKP CHILP RORγt, which develops into either a common PLZF RUNX3 helper innate lymphoid progenitor 2 Basophil (CHILP) under the influence of E-cadherin Keratinocyte 3 Fibrosis IL-6, ? ILCP LTiP transcription factors such as TCF1 and KLRG1 IL-8, proliferation EOMES, AHR, 4 IL-13 B cell IL-15, EOMES, ID2, or into an NK cell progenitor (NKP) DC CCL20 RORγt, + IL-22 T-bet T-bet BCL-11B, under the additional influence of EOMES ILC2 NCR RUNX3 IL-9 IL-4 IgE isotype GATA3, IL-2, and NFIL3. The subsequent expression of switch ILC3 IL-17 Notch, ROR TOX IL-25, IL-2 ILC2P α RORγt by the CHILP leads to LTi cell Homeostatic IL-33, TSLP suppression of T 2 IL-1β, RUNX3, differentiation via the LTi cell precursor H BCL-11B, ILC2 function ILC2 cell IL-23 T-bet (LTiP), whereas PLZF expression marks Periphery GFI1, TCF1 PGD the development of the ILC progenitor 2 Neutrophil IL-4, GM-CSF NCR+ NCR– LTi Mast cell NCR– NK iILC1 ILC1 ILC2 exILC3 (ILCP) which, under the influence of IL-5 IL-13 DC cell ILC3 ILC3 cell T-bet, GATA3 or RORγt, gives rise to the M1 ILC3 5 Activating IL-12, IL-12, IL-12, IL-2, IL-25, IL-2, IL-1β, IL-1β, IL-1β, ILC1, ILC2 or ILC3 subsets, respectively . Eosinophilia M2 IL-2, IL-2, IL-2, NCR+ ILC3s are characterized by IL-22 factors IL-15, IL-15 IL-18 IL-33, PGD2, IL-12, IL-18 TL1, TSLP IL-18 IL-6, IL-6, IL-23 production, whereas NCR– ILC3 produce IL-23 IL-23 IL-17. Both subsets can differentiate into ILC2s are involved in Effector IFNγ, granzymes, IFNγ AREG, GM-CSF, IFNγ GM-CSF, GM-CSF, IL-17, IFNγ-producing exILC3s. The molecules perforin IL-4, IL-5, IL-9, IL-22, LT, IL-17, IL-22, development of intraepithelial ILC1s Several mouse models and clinical observations support a role for IL-13 TNF LT LT, TNF 6,7,8 (iILC1s) remains to be elucidated. ILC2s in type 2 inflammation in the skin, lungs and intestine . ILC2 activation is triggered by IL-25, IL-33, TSLP and PGD2 produced by activated epithelial cells or immune cells in response to helminth infections or allergen exposure. The effector functions of ILC2s are Lung largely mediated by IL-4, IL-5, IL-9 and IL-13 and promote goblet cell The yin and yang of ILC3s Homeostasis and Airway hyperresponsiveness Obesity-induced airway hyperplasia, production, eosinophilia, IgE isotype switching tissue repair and asthma hyperresponsiveness and fibrosis1. Importantly, these mechanisms are mainly protective in IL-22 produced by NCR+ ILC3s binds to the IL-22 OVA, papain, Goblet Goblet cell the setting of helminth infection, in which ILC2 responses are driven receptor, which is exclusively expressed by non- Virus HDM or LPS cell hyperplasia predominantly by IL-33 but can become exaggerated and cause haematopoietic cells. The tissue protective role of pathology in allergy and asthma. Interestingly, ILC2s display functional IL-22 in the intestine during intestinal infection has 10 Repair plasticity, and inflammatory ILC2s may also differentiate into IL-17- been well documented and includes promotion 9 Basophil producing ILC3-like cells and participate in antifungal immunity . of epithelial cell fucosylation, which supports Fibrosis Mucus Airway remodelling IL-33 AREG and neutrophil influx host–microbiota symbiosis. However, the potent production ILC2 plasticity capacity of IL-22 to induce proliferation of stromal LXA4 ILC2 IL-17 cells also implies that excessive IL-22 production DC hi IL-13 KLRG1 Inflammatory IL-4 IgE isotype may lead to pathology. Indeed, in a mouse model IL-25, B cell ILC2 of colorectal cancer, tumour growth was enhanced IL-33, ICOSL IL-2 switch ILC3 IL-17RB ILC3- 11 TL1, TSLP ICOS Candida like by ILC3-derived IL-22 . Intriguingly, whereas IL-22 T 2 IL-25 ILC2 H albicans seems mainly protective in the intestine, IL-22- cell IL-1β Nippostrongylus IL-2, producing ILC3s accumulate in the skin of patients GM-CSF LTD 4 brasiliensis IL-7, with psoriasis12 and, supported by observations in IL-33 IL-5, IL-17 13 ILC2 low IL-13 a mouse model of psoriasis , this suggests a M1 KLRG1 IL-9 IL-5 IL-4, disease-promoting role for these cells in this tissue. IL-13 Macrophage IL-33 IL-13 Furthermore, in the lungs, ILC3s may promote PGD M2 2 ST2 Natural ILC2-like obesity-induced airway hyperresponsiveness through the production of IL-17. Mast cell Eosinophilia High-fat diet

Source? Beige Intestine adipocyte Metabolic homeostasis Acute IBD Homeostasis and Tumour Helminth infection or IL-25, infection tissue repair allergen exposure IL-33, IL-13, Intestinal VIP MetEnk Mucus Beiging Intracellular layer Goblet epithelial ILC2 pathogen • Stem cell cell cell regeneration • Epithelial White fucosylation The role for ILCs in homeostasis and tissue repair adipocyte Repair Important tissue protective effects of ILC2s and ILC3s have been Neutrophil Phagocytosis Mucins, IL-25, Mucus described. ILC3s produce IL-22, which is crucial for the repair of IL-33 AREG IL-33, production DC Neutrophil and AMPs, thymic tissue following viral infection14 and for intestinal mucosal cytotoxicity proliferation IL-9 TSLP recruitment LT, barrier protection10. In addition, ILC3s can suppress commensal- iILC1 IFNγ ILC2 IL-22 specific T 17 cells through IL-2 consumption, preventing intestinal IL-12, IL-13 H ILC2 Fibrosis 15 IL-18 IL-17 IL-22BP inflammation . In the spleen, ILC3s interact with adaptive immune + 16 IL-2 cells to maintain memory CD4 T cells and marginal zone (MZ) ILC1 IL-25 B cells17. Furthermore, ILC2s in adipose tissue produce met- ILC1 IL-5 IgE B cell isotype enkephalin (MetEnk), which promotes beiging of adipose tissue18. T 2 ILC3 H switch Lung ILC2s contribute to tissue restoration upon viral insult ILC3 exILC3 cell IFNγ IL-6, through the production of AREG19. IL-23 IL-1β, MHC IL-12, IL-23, Antigen Proliferation retinoic and type 2 Spleen and thymus IL-18 TCR M1 IFNγ acid cytokine production Tissue TH17 cell Stromal restoration Bacterial M1 Eosinophilia after injury killing cell ↑ ICAM1 Inhibition of MSC ↑ VCAM1 commensal-specific IL-22, Tolerogenic T 17 cells through MADCAM1 H LTβ , • Survival DC IL-2 consumption LTα α4β7 TNF • Proliferation IL-23 integrin CD40L • IgM, IgA and ILCs contribute to intestinal inflammation and are functionally plastic DC CD40 IgG production • Plasmablast 20 CD4+ MZ Human inflammatory bowel disease (IBD) is associated with an increased frequency of IL-17-producing ILC3s , which parallels findings in mice, in ILC3 differentiation T cell B cell which Helicobacter hepaticus-induced colitis increases the number of IL-17- and IFNγ-producing ILC3s21. Noteworthy, neutralization of IL-17 in this DLL1 model, or in clinical trials, does not ameliorate disease, pointing towards a crucial role for ILC3-derived IFNγ in IBD. In mice, intestinal environmental CD30L APRIL cues induce T-bet expression in RORγt+NCR+ ILC3s, which is crucial for defence against Salmonella infection22. However, this causes collateral T cell memory CD30 OX40L BAFF maintenance damage that presents as enterocolitis. Paralleling these observations, human Crohn's disease is associated with an accumulation of IFNγ-producing OX40 + ILC1s23. ILC1s can be derived from ILC3s under the influence of IL-12, whereas IL-23 and retinoic acid exposure lead to ILC3 re-differentiation24. CD4 Neutrophil T cell GM-CSF Hence, a finely tuned balance of ILC1s and ILC3s ensures tissue integrity while maintaining immune defence in the intestine.

STEMCELL Technologies • RoboSep™ (www.RoboSep.com), the fully Abbreviations Affiliations STEMCELL Technologies offers a complete portfolio of automated cell isolation platform, performs all AHR, aryl hydrocarbon receptor; AMPs, antimicrobial peptides; APRIL, a proliferation-inducing Jenny Mjösberg is at the Center for Infectious Medicine, Department ligand; AREG, amphiregulin; BAFF, B cell activating factor; BCL-11B, B cell lymphoma 11B; of Medicine Huddinge, Karolinska University Hospital Huddinge, fast and easy cell isolation products, including solutions cell labeling and magnetic isolation steps using CCL20, CC-chemokine ligand 20; CD30L, CD30 ligand; CD40L, CD40 ligand; DC, ; for the isolation of ILCs. Our wide range of positive and EasySep™ reagents to reduce hands-on time and Karolinska Institutet, S-14186 Stockholm, Sweden. DLL1, delta-like protein 1; EILP, early ILC progenitor; EOMES, eomesodermin; GFI1, growth ([email protected]) negative cell isolation kits are proven to rapidly give increase laboratory throughput. factor independent protein 1; GM-CSF, granulocyte–macrophage colony-stimulating factor; you high recovery and purity of functional cells from • RosetteSepTM (www.RosetteSep.com) is a unique HDM, house dust mite; ICAM1, intercellular adhesion molecule 1; ICOS, inducible T cell The author apologizes to colleagues whose work has not been cited virtually any sample source including fresh and immunodensity cell isolation system for the isolation costimulator; ICOSL, ICOS ligand; ID2, inhibitor of DNA binding 2; IFNγ, interferon-γ; owing to space limitations. previously frozen peripheral blood mononuclear cells of untouched cells directly from whole blood during IL, interleukin; IL-17RB, IL-17 receptor B; IL-22BP, IL-22 binding protein; KLRG1, killer-cell lectin like References and a table of the surface markers expressed by human receptor G1; LTD , leukotriene D ; LPS, lipopolysaccharide; LT, lymphotoxin; LT R, lymphotoxin- (PBMCs), Leuko Paks, whole blood, bone marrow, lymph the standard density centrifugation step. 4 4 β β and mouse ILCs are available online. receptor; LXA , lipoxin A ; M1, type 1 macrophage; M2, type 2 macrophage; MADCAM1, mucosal nodes, and spleen. For more information on the complete range of cell 4 4 addressin cell adhesion molecule 1; NCR, natural cytotoxicity receptor; NFIL3, nuclear factor IL-3 • EasySep™ (www.EasySep.com) is a fast, easy and separation products available, or to learn more about Edited by Olive Leavy and Jamie D. K. Wilson; copy-edited by induced; OVA, ovalbumin; OX40L, OX40 ligand; PGD , prostaglandin D ; PLZF, promyelocytic 2 2 Gemma Ryan; designed by Kirsten Lee and Simon Bradbrook. column-free immunomagnetic cell separation system primary cells, cell culture media, antibodies or other leukaemia zinc finger protein; ROR, retinoic acid receptor-related orphan receptor; RUNX3, for isolating highly purified immune cells in as little as products for your immune cell workflow, please visit runt-related 3; ST2, IL-33 receptor; TCF1, T cell factor 1; TCR, T cell receptor; 8 minutes. Cells are immediately ready for our website: www.stemcell.com TH, T helper; TL1, TNF-like ligand 1; TNF, tumor necrosis factor; TSLP, thymic stromal lymphopoietin; © 2015 Nature Publishing Group. All rights reserved. downstream functional assays. Document # 27005 Version 1.0.0 VCAM1, vascular cell adhesion molecule 1; VIP, vasoactive intestinal peptide. www.nature.com/posters/ilcs/index.html