Paeoniflorin ameliorates chronic colitis via the DR3 signaling pathway in group 3 innate lymphoid cells

Inhibiting the death receptor 3(DR3)signaling pathway in group 3 innate lymphoid cells(ILC3s)presents a promising approach for promoting mucosal repair in individuals with ulcerative colitis(UC).Paeoniflorin,a prominent component of Paeonia lactiflora Pall.,has demonstrated the ability to restore barrier function in UC mice,but the precise mechanism remains unclear.In this study,we aimed to delve into whether paeoniflorin may promote intestinal mucosal repair in chronic colitis by inhibiting DR3 signaling in ILC3s.C57BL/6 mice were subjected to random allocation into 7 distinct groups,namely the control group,the 2%dextran sodium sulfate(DSS)group,the paeoniflorin groups(25,50,and 100 mg/kg),the anti-tumor necrosis factor-like ligand 1A(anti-TL1A)antibody group,and the IgG group.We detected the expression of DR3 signaling pathway proteins and the proportion of ILC3s in the mouse colon using Western blot and flow cytometry,respectively.Meanwhile,DR3-overexpressing MNK-3 cells and 2%DSS-induced Rag1^(-/-)mice were used for verification.The results showed that paeoniflorin alleviated DSS-induced chronic colitis and repaired the intestinal mucosal barrier.Simultaneously,paeoniflorin inhibited the DR3 signaling pathway in ILC3s and regulated the content of cytokines(interleukin-17A,granulocyte-macrophage colony stimulating factor,and interleukin-22).Alternatively,paeoniflorin directly inhibited the DR3 signaling pathway in ILC3s to repair mucosal damage independently of the adaptive immune system.We additionally confirmed that paeoniflorin-conditioned medium(CM)restored the expression of tight junctions in Caco-2 cells via coculture.In conclusion,paeoniflorin ameliorates chronic colitis by enhancing the intestinal barrier in an ILC3-dependent manner,and its mechanism is associated with the inhibition of the DR3 signaling pathway.

Ambiguous roles of innate lymphoid cells in chronic development of liver diseases

Innate lymphoid cells(ILCs) are defined as a distinct arm of innate immunity. According to their profile of secreted cytokines and lineage-specific transcriptional factors, ILCs can be categorized into the following three groups: group 1 ILCs(including natural killer(NK) cells and ILC1 s) are dependent on T-bet and can produce interferon-γ; group 2 ILCs(ILC2 s) are dependent on GATA3 and can produce type 2 cytokines, including interleukin(IL)-5 and IL-13; and, group 3 ILCs(including lymphoid tissue-like cells and ILC3 s) are dependent on RORγt and can produce IL-22 and IL-17. Collaborative with adaptive immunity, ILCs are highly reactive innate effectors that promptly orchestrate immunity, inflammation and tissue repair. Dysregulation of ILCs might result in inflammatory disorders. Evidence regarding the function of intrahepatic ILCs is emerging from longitudinal studies of inflammatory liver diseases wherein they exert both physiological and pathological functions, including immune homeostasis, defenses and surveillance. Their overall effect on the liver depends on the balance of their proinflammatory and antiinflammatory populations, specific microenvironment and stages of immune responses. Here, we review the current data about ILCs in chronic liver disease progression, to reveal their roles in different stages as well as to discuss their therapeutic potency as intervention targets.

Innate lymphoid cells in tissue homeostasis and diseases

Innate lymphoid cells(ILCs) are the most recently discovered family of innate immune cells. They are a part of the innate immune system, but develop from the lymphoid lineage. They lack pattern-recognition receptors and rearranged receptors, and therefore cannot directly mediate antigen specific responses. The progenitors specifically associated with the ILCs lineage have been uncovered, enabling the distinction between ILCs and natural killer cells. Based on the requirement of specific transcription factors and their patterns of cytokine production, ILCs are categorized into three subsets(ILC1, ILC2 and ILC3). First observed in mucosal surfaces, these cell populations interact with hematopoietic and non-hematopoietic cells throughout the body during homeostasis and diseases, promoting immunity, commensal microbiota tolerance, tissue repair and inflammation. Over the last 8 years, ILCs came into the spotlight as an essential cell type able to integrate diverse host immune responses. Recently, it became known that ILC subsets play a key role in immune responses at barrier surfaces, interacting with the microbiota, nutrients and metabolites. Since the liver receives the venous blood directly from the intestinal vein, the intestine and liver are essential to maintain tolerance and can rapidly respond to infections or tissue damage. Therefore, in this review, we discuss recent findings regarding ILC functions in homeostasis and disease, with a focus on the intestine and liver.

The origin and role of innate lymphoid cells in the lung

Innate lymphoid cells(ILCs),a newly identified member of the lymphoid population,play a critical role in the transition from innate to adaptive immunity in host defense.ILCs are important in mucosal barrier immunity,tissue homeostasis,and immune regulation throughout the body.Significant alterations in ILC responses in lung diseases have been observed and reported.Emerging evidence has shown that ILCs are importantly involved in the pathogenesis and development of a variety of lung diseases,i.e.,helminth infections,allergic airway inflammation,and airway hyper-responsiveness.However,as a tissue-resident cell population,the role of ILCs in the lung remains poorly characterized.In this review,we discuss the role of ILCs in lung diseases,the mechanisms underlying the ILCmediated regulation of immunity,and the therapeutic potential of modulating ILC responses.

Mahuang Xixin Fuzi decoction protects against ovalbumin-induced allergic rhinitis by inhibiting type 2 innate lymphoid cells in mice

Objective:As a traditional herbal formula,Mahuang Xixin Fuzi decoction(MXFD)has been used to treat allergic rhinitis(AR).It regulates the transcription factor GATA3 in T cells,blocks Th2 skewing and rebalances the Th1/Th2 immunity.Type 2 innate lymphoid cells(ILC2s)are closely associated with GATA3.However,it remains unknown whether ILC2s could be one mechanism through which MXFD acts.We sought to elucidate the efficacy and mechanism of action of this decoction in AR treatment.Methods:Forty C57BL/6J female mice were equally divided into control,model,loratadine-and MXFDtreated groups in random.AR was induced by ovalbumin(OVA),and then treatment with loratadine or MXFD was administered.AR scores were evaluated and compared before and after treatment.Pathological changes in the nasal mucosa and lung were observed using hematoxylin-eosin staining of tissue samples.Activation of ILC2 in nasal mucosa was assessed by immunofluorescence and quantitative polymerase chain reaction analysis.ILC2 cell count in lungs was measured by flow cytometry and levels of interleukin-(IL)4,IL-5 and IL-13 in serum were detected by ELISA.Results:The decoction alleviated the symptoms of AR in mice,improved vascular congestion and expansion,glandular hyperplasia and inflammatory cell infiltration in mouse nasal mucosa and slowly improved the interstitial pneumonia and lesions.Meanwhile,MXFD reduced the number and percentage of ILC2s in the nasal mucosa and lungs,downregulated the expression of GATA3 mRNA and RORa mRNA,and reduced the related inflammatory cytokine levels,including IL-4,IL-5 and IL-13.Conclusion:These data suggest that inhibition of ILC2s by MXFD may be an important means by which to treat AR.

AB003.Local group 2 innate lymphoid cells promote corneal regeneration after epithelial abrasion

Corneal injuries and infections are the leading cause of blindness worldwide.Thus,understanding the mechanisms that control healing of the damaged cornea is critical for the development of new therapies to promptly restore vision.Innate lymphoid cells(ILCs)are a recently identified heterogeneous cell population that has been reported to orchestrate immunity and promote tissue repair in the lungs and skin after injury.However,whether ILCs can modulate the repair process in the cornea remains poorly understood.We identified a population of cornea-resident group 2 ILCs(ILC2s)in mice that express CD127,T1/ST2,CD90,and cKit.This cell population was relatively rare in corneas at a steady state but increased after corneal epithelial abrasion.Moreover,ILC2s were maintained and expanded locally at a steady state and after wounding.Depletion of this cell population caused a delay in corneal wound healing,whereas supplementation of ILC2s through adoptive transfer partially restored the healing process.Further investigation revealed that IL-25,IL-33,and thymic stromal lymphopoietin had critical roles in corneal ILC2 responses and that CCR2-corneal macrophages were an important producer of IL-33 in the cornea.Together,these results reveal the critical role of cornea-resident ILC2s in the restoration of corneal epithelial integrity after acute injury and suggest that ILC2 responses depend on local induction of IL-25,IL-33,and thymic stromal lymphopoietin.

The protective roles of integrin α4β7 and Amphiregulin-expressing innate lymphoid cells in lupus nephritis

Type 2 innate lymphoid cells (ILC2s) have emerged as key regulators of the immune response in renal inflammatory diseases such as lupus nephritis. However, the mechanisms underlying ILC2 adhesion and migration in the kidney remain poorly understood. Here, we revealed the critical role of integrin α4β7 in mediating renal ILC2 adhesion and function. We found that integrin α4β7 enables the retention of ILC2s in the kidney by binding to VCAM-1, E-cadherin, or fibronectin on structural cells. Moreover, integrin α4β7 knockdown reduced the production of the reparative cytokine amphiregulin (Areg) by ILC2s. In lupus nephritis, TLR7/9 signaling within the kidney microenvironment downregulates integrin α4β7 expression, leading to decreased Areg production and promoting the egress of ILC2s. Notably, IL-33 treatment upregulated integrin α4β7 and Areg expression in ILC2s, thereby enhancing survival and reducing inflammation in lupus nephritis. Together, these findings highlight the potential of targeting ILC2 adhesion as a therapeutic strategy for autoimmune kidney diseases.

Tissue-resident memory-like ILCs: innate counterparts of TRM cells

Innate lymphoid cells(ILCs)are defined as lymphocytes that lack RAG recombinase and do not express diverse antigen receptors;however,recent studies have revealed the adaptive features of ILCs.Mouse cytomegalovirus(MCMV)-and cytokine-induced memory natural killer(NK)cells circulate in the blood and are referred to as conventional memory NK cells.In contrast,virusand hapten-induced memory NK cells,hapten-induced memory ILC1s,and cytokine-induced memory-like ILC2s exhibit long-term residency in the liver or lung,and are referred to as tissue-resident memory ILCs.Considering their similar migration patterns and memory potential,tissue-resident memory ILCs could be regarded as innate counterparts of resident memory T(T r m)cells.Both tissue-resident memory ILCs and TRM cells share common characteristics in terms of dynamics,phenotype,and molecular regulation.The emergence of ILC memory expands the basic biology of ILCs and prompts us to re-examine their functions in disease progression.This review discusses the evidence supporting tissue-resident memory NK cells and other memory ILC subsets,compares them with TRM cells,and highlights key unsolved questions in this emerging field.

ILC2和MDSC及其相关细胞因子IL-13和iNOS在宫颈癌中的表达及其列线图模型的构建和评价

目的:研究2型固有淋巴样细胞(ILC2)和髓源性抑制细胞(MDSC)及其相关细胞因子IL-13和诱导型一氧化氮合酶(iNOS)在宫颈癌(CC)中的表达,并基于其构建CC发病风险的列线图预测模型。方法:采集2022年5月至2024年1月在新疆医科大学第一附属医院手术切除的40例CC组织及100例外周血作为CC组,选取同期收治的30例子宫肌瘤经CC筛查为阴性的宫颈组织和100例正常健康个体外周血作为对照组。用多重免疫荧光技术(mIF)及免疫组化染色(IHC)法检测两组组织中ILC2和MDSC细胞浸润及其相关细胞因IL-13和iNOS的表达;使用流式细胞术和ELISA技术分别检测两组外周血中ILC2和MDSC及IL-13和iNOS的表达差异;通过Person相关性分析评估其相关性;使用单因素和多因素Logistic分析来确定ILC2和MDSC及IL-13和iNOS是否为CC发病的独立危险因素,再利用R软件建立免疫预测模型,使用ROC曲线下面积(AUC值)、Hosmer-Lemeshow检验、校准曲线、临床决策曲线和临床影响曲线来分别评估模型。结果:CC组中ILC2及MDSC及其相关细胞因子IL-13和iNOS均高于对照组(均P<0.05),且其均呈正相关(均P<0.05);经过单因素及多因素Logistic回归分析显示,ILC2、MDSC及IL-13、iNOS均是CC发病的独立危险因素(均P<0.05);基于这些危险因素的CC发病列线图,经过验证提示,该列线图模型具有一定的临床实用价值。结论:ILC2和MDSC及其相关的细胞因子IL-13和iNOS在CC组织及外周血中均呈高表达,基于这些危险因素构建的预测模型具有良好的预测能力和一定的实用性,为CC的早期诊断和治疗提供了一种简便有效的辅助工具。

ILC3/IL-22在细菌性肺炎中的抗菌免疫研究进展

Ⅲ型固有淋巴细胞(ILC3)是一种新型淋巴细胞,激活后通过产生白细胞介素-22(IL-22)和白细胞介素-17(IL-17)发挥抗菌和修复黏膜损伤的作用,本综述主要探讨ILC3/IL-22在细菌性肺炎中介导抗菌免疫的作用和机制,以期为细菌性肺炎的防控提供理论依据和研究思路。

MiR-142-3p Regulates ILC1s by Targeting HMGB1 via the NF-κB Pathway in a Mouse Model of Early Pregnancy Loss

Objective Innate lymphoid cells(ILCs)are a class of newly discovered immunocytes.Group 1 ILCs(ILC1s)are identified in the decidua of humans and mice.High mobility group box 1(HMGB1)is predicted to be one of the target genes of miR-142-3p,which is closely related to pregnancy-related diseases.Furthermore,miR-142-3p and HMGB1 are involved in regulating the NF-κB signaling pathway.This study aimed to examine the regulatory effect of miR-142-3p on ILC1s and the underlying mechanism involving HMGB1 and the NF-κB signaling pathway.Methods Mouse models of normal pregnancy and abortion were constructed,and the alterations of ILC1s,miR-142-3p,ILC1 transcription factor(T-bet),and pro-inflammatory cytokines of ILC1s(TNF-α,IFN-γand IL-2)were detected in mice from different groups.The targeting regulation of HMGB1 by miR-142-3p in ILC1s,and the expression of HMGB1 in normal pregnant mice and abortive mice were investigated.In addition,the regulatory effects of miR-142-3p and HMGB1 on ILC1s were detected in vitro by CCK-8,Annexin-V/PI,ELISA,and RT-PCR,respectively.Furthermore,changes of the NF-κB signaling pathway in ILC1s were examined in the different groups.For the in vivo studies,miR-142-3p-Agomir was injected in the uterus of abortive mice to evaluate the abortion rate and alterations of ILC1s at the maternal-fetal interface,and further detect the expression of HMGB1,pro-inflammatory cytokines,and the NF-κB signaling pathway.Results The number of ILC1s was significantly increased,the level of HMGB1 was significantly upregulated,and that of miR-142-3p was considerably downregulated in the abortive mice as compared with the normal pregnant mice(all P<0.05).In addition,miR-142-3p was found to drastically inhibit the activation of the NF-κB signaling pathway(P<0.05).The number of ILC1s and the levels of pro-inflammatory cytokines were significantly downregulated and the activation of the NF-κB signaling pathway was inhibited in the miR-142-3p Agomir group(all P<0.05).Conclusion miR-142-3p can regulate ILC1s by targeting HMGB1 via the NF-κB signaling pathway,and attenuate the inflammation at the maternal-fetal interface in abortive mice.

CD226在小鼠小肠3型固有淋巴样细胞(ILC3)中的表达

目的 观察CD226在小肠3型固有淋巴样细胞(ILC3)上的表达情况。方法 采用生物信息学方法分析小鼠CD226在ILC中的表达。分离正常C57BL/6J小鼠小肠黏膜固有层淋巴细胞(LPL),流式细胞术检测CD226在ILC1和ILC3上的表达。构建葡聚糖硫酸钠(DSS)诱导小鼠肠炎模型,观察CD226在ILC3上表达的变化情况。结果 小鼠小肠ILC1和ILC3均表达CD226;肠炎模型中ILC3所占比例降低,但CD226在ILC3上的表达水平升高。结论 小鼠小肠表达CD226,DSS诱导的肠炎模型中虽然ILC3比例降低,但CD226在ILC3的表达增加。

ILC2细胞、肠道微生态与牛奶蛋白过敏关系的研究进展

2型固有淋巴细胞(ILC2)是一种免疫细胞,可分泌辅助性T细胞2,参与呼吸道过敏、蠕虫感染等疾病的发生发展。牛奶蛋白过敏(CMPA)是一种口服耐受建立失败而引起的多器官甚至全身过敏状态。受饮食方式和环境变化的影响,肠道微生态失衡导致儿童中CMPA的发生率逐年攀升。近年来对免疫相关细胞群体的研究表明,ILC2在肠道局部免疫中起重要作用。ILC2的激活和功能表达离不开肠道菌群产生的细胞因子和代谢物,未来对过敏肠道内ILC2的代谢组学研究,或将成为治疗CMPA的靶细胞。

Suppression of Immunotherapy on Group 2 Innate Lymphoid Cells in Allergic Rhinitis

Background： Group 2 innate lymphoid cells （ILC2s） are regarded as a novel population of lineage-negative cells that induce innate Type 2 responses by producing the critical Th2-type cytokines interleukin （IL）-5 and IL-13. ILC2s as key players in the development of allergic rhinitis （AR） have been proved, however, the effect of subcutaneous immunotherapy （SCIT） with dermatophagoides pteronyssinus extract （Der p-SCIT） on ILC2s in AR patients is not clear. This study aimed to investigate the response of ILC2s of peripheral blood in house dust mites （HDM）-sensitized Chinese patients with AR who received SCIT with Der P extract. Methods： Seven healthy controls without symptoms of AR who had negative reactions to any of the allergens from skin-prick testing, nine patients diagnosed with persistent AR according to the Allergic Rhinitis and its Impact on Asthma （ARIA） guidelines, and 24 AR patients who received Der p-SCIT for 1.0-3.5 years were recruited for the study. ILC2s in the peripheral blood were evaluated using flow cytometry. The severity of their symptoms of all participants was rated based on the Total 5 symptom score. Results： Among 40 participants, 9 AR patients were assigned to the untreated group, 24 AR patients receiving Der p-SCIT were assigned to the immunotherapy group, and 7 healthy controls without symptoms of AR were assigned to healthy control group. The mean Total 5 symptom score of immunotherapy group was significantly lower than that of untreated group （4.3 ± 1.4 vs. 10.1 ± 2.5, P 〈 0.001 ）. Similarly, the levels of ILC2s in the peripheral blood ofimmunotherapy group were significantly reduced compared with that in untreated group （P 〈 0.001 ）, but were not significantly different from healthy controls （P = 0.775）. Further subgroup analysis based on the duration of SCIT therapy （ 1.0-2.0 years [SCIT1-2], 2.0-3.0 years [SCIT2_3], and 3.0-3.5 years [SCIT3_3.5]） showed that the percentage of ILC2s was not significantly different between SCIT1-2, SCIT2-3, and SCIT3-3.5 groups （SCIT1-2 vs. SCIT2-3： P = 0.268; SCIT1-2, vs. SCIT3-3.5： P = 0.635; and SCIT, 3 vs. SCIT3-3.5： P = 0.787）. Conclusions： The present study highlighted the suppression ofDer p-SCIT on ILC2s in HDM-AR patients. ILC2s identified in peripheral blood can be used as an effective biomarker for Der p-SCIT.

Guards at the gate： physiological and pathological roles of tissue-resident innate lymphoid cells in the lung

The lung Is an Important open organ and the primary site of respiration. Many life.threatening diseases develop in the lung, e.g., pneumonia, asthma, chronic obstructive pulmonary diseases （COPDs）, pulmonary fibrosis, and lung cancer. In the lung, innate Immunity serves as the frontline in both anti-irritant response and anti-tumor defense and is also critical for mucosal homeostasis; thus, it plays an important role In containing these pul- monary diseases. Innate lymphoid cells （ILCs）, charac. terized by their strict tissue residence and distinct function in the mucosa, are attracting Increased atten. tion In innate Immunity. Upon sensing the danger slg- nals from damaged epithelium, ILCs activate, proliferate, and release numerous cytoklnes with specific local functions; they also participate in mucosal immune- surveillance, Immune-regulation, and homeostasis. However, when their functions become uncontrolled, ILCs can enhance pathological states and Induce dis- eases. In this review, we discuss the physiologicel and pathological functions of ILC subsets 1 to 3 in the lung, and how the pathogenic environment affects the func- tion and plasticity of ILCs.

The transcription factor RelB restrains group 2 innate lymphoid cells and type 2 immune pathology in vivo

The exact relationships between group 2 innate lymphoid cells(ILC2s)and Th2 cells in type 2 pathology,as well as the mechanisms that restrain the responses of these cells,remain poorly defined.Here we examined the roles of ILC2s and Th2 cells in type 2 lung pathology in vivo using germline and conditional fie/b-deficient mice.We found that mice with germline deletion of Relb^(-/-)spontaneously developed prominent type 2 pathology in the lung,which contrasted sharply with mice with T-cell-specific Relb deletion(Relb^(f/f)Cd4-Cre),which were healthy with no observed autoimmune pathology.We also found that in contrast to wild-type B6 mice,Rel6-defident mice showed markedly expanded ILC2s but not ILC1s or ILC3s.Moreover,adoptive transfer of naive CD4^(+)T cells into Rag1^(-/-)Relb^(-/-)hosts induced prominent type 2 lung pathology,which was inhibited by depletion of ILC2s.Mechanistically,we showed that Relb deletion led to enhanced expression of Bcl11b,a key transcription factor for ILC2s.We concluded that RelB plays a critical role in restraining ILC2s,primarily by suppressing Bcl11b activity,and consequently inhibits type 2 lung pathology in vivo.

Allium tuberosum alleviates pulmonary inflammation by inhibiting activation of innate lymphoid cells and modulating intestinal microbiota in asthmatic mice

Objective:This study tests whether long-term intake of Allium tuberosum(AT)can alleviate pulmonary inflammation in ovalbumin(OVA)-induced asthmatic mice and evaluates its effect on the intestinal microbiota and innate lymphoid cells(ILCs).Methods:BALB/c mice were divided into three groups:phosphate buffer saline,OVA and OVA+AT.The asthmatic murine model was established by sensitization and challenge of OVA in the OVA and OVA+AT groups.AT was given to the OVA+AT group by oral gavage from day 0 to day 27.On day 28,mice were sacrificed.Histopathological evaluation of lung tissue was performed using hematoxylin and eosin,and periodic acid-Schiff staining.The levels of IgE in serum,interleukin-5(IL-5)and IL-13 from bronchoalveolar lavage fluid(BALF)were measured by enzyme-linked immunosorbent assay.The ILCs from the lung and gut were detected by flow cytometry.16 S ribosomal DNA sequencing was used to analyze the differences in colon microbiota among treatment groups.Results:We found that long-term intake of AT decreased the number of inflammatory cells from BALF,reduced the levels of IL-5 and IL-13 in BALF,and IgE level in serum,and rescued pulmonary histopathology with less mucus secretion in asthmatic mice.16 S ribosomal DNA sequencing results showed that AT strongly affected the colonic bacteria community structure in asthmatic mice,although it had no significant effect on the abundance and diversity of the microbiota.Ruminococcaceae and Desulfovibrionaceae were identified as two biomarkers of the treatment effect of AT.Moreover,AT decreased the numbers of ILCs in both the lung and gut of asthmatic mice.Conclusion:The results indicate that AT inhibits pulmonary inflammation,possibly by impeding the activation of ILCs and adjusting the homeostasis of gut microbiota in asthmatic mice.

NKR-P1B expression in gut-associated innate lymphoid cells is required for the control of gastrointestinal tract infections

Helper-type innate lymphoid cells(ILC)play an important role in intestinal homeostasis.Members of the NKR-P1 gene family are expressed in various innate immune cells,including natural killer(NK)cells,and their cognate Clr ligand family members are expressed in various specialized tissues,including the intestinal epithelium,where they may play an important role in mucosalassociated innate immune responses.In this study,we show that the inhibitory NKR-P1B receptor,but not the Ly49 receptor,is expressed in gut-resident NK cells,ILC,and a subset ofγδT cells in a tissue-specific manner.ILC3 cells constitute the predominant cell subset expressing NKR-P1B in the gut lamina propria.The known NKR-P1B ligand Clr-b is broadly expressed in gut-associated cells of hematopoietic origin.The genetic deletion of NKR-P1B results in a higher frequency and number of ILC3 andγδT cells in the gut lamina propria.However,the function of gut-resident ILC3,NK,andγδT cells in NKR-P1B-deficient mice is impaired during gastrointestinal tract infection by Citrobacter rodentium or Salmonella typhimurium,resulting in increased systemic bacterial dissemination in NKR-P1B-deficient mice.Our findings highlight the role of the NKR-P1B:Clr-b recognition system in the modulation of intestinal innate immune cell functions.

Sensing of physiological regulators by innate lymphoid cells

Maintenance of homeostasis and immune protection rely on the coordinated action of different physiological systems.Bidirectional communication between the immune system and physiological systems is required to sense and restore any disruption of equilibrium.Recent transcriptomic analyses of innate lymphoid cells(ILCs)from different tissues have revealed that ILCs express a large array of receptors involved in the recognition of neuropeptides,hormones and metabolic signals.ILCs rapidly secrete effector cytokines that are central in the development and activation of early immune responses,but they also constitutively secrete mediators that are important for tissue homeostasis.To achieve these functions effectively,ILCs integrate intrinsic and extrinsic signals that modulate their constitutive and induced activity.Disruption of the regulation of ILCs by physiological regulators leads to altered immune responses with harmful consequences for the organism.An understanding of these complex interactions between the immune system and physiological mediators is crucial to decipher the events leading to the protective versus pathological effects of these cells.

Reciprocal costimulatory molecules control the activation of mucosal type 3 innate lymphoid cells during engagement with B cells

Innate lymphoid cells(ILCs)are the counterpart of T helper cells in the innate immune system and share multiple phenotypes with T helper cells.Inducible T-cell costimulator(ICOS)is recognized on T cells and participates in T-cell activation and T and B-cell engagement in lymphoid tissues.However,the role of ICOS in ILC3s and ILC3-involved interactions with the immune microenvironment remains unclear.Here,we found that ICOS expression on human ILC3s was correlated with the activated state of ILC3s.ICOS costimulation enhanced the survival,proliferation,and capacity of ILC3s to produce cytokines(IL-22,IL-17A,IFN-γ,TNF,and GM-CSF).Via synergistic effects of ICOS and CD40 signaling,B cells promoted ILC3 functions,and ILC3-induced T-cellindependent B-cell IgA and IgM secretion primarily required CD40 signaling.Hence,ICOS is essential for the nonredundant role of ILC3s and their interaction with adjacent B cells.