Project description:Innate lymphoid cells (ILCs) are tissue-resident lymphocytes that lack antigen-specific receptors and exhibit innate effector functions such as cytokine production that play an important role in immediate responses to pathogens especially at mucosal sites. Mouse and human ILC subsets have been extensively characterized in various tissues and in blood. In this study, we present the first characterization of ILCs and ILC subsets in rat gut and secondary lymphoid organs. ScRNAseq and flow cytometric data shows that phenotype and function of rat ILC subsets are conserved similar to human and mouse ILCs. However, contrary to human and mouse, our study unexpectedly revealed that ILC2 and not ILC3 was by far the dominant ILC subset in the rat intestinal lamina propria. ILC2 predominance in the gut was independent of rat strain, sex or housing facility. In contrast, ILC3 were the main ILC subset in mesenteric lymph nodes and Peyer patches, in which strain-dependent differences in ILC frequencies were also observed. In conclusion, our study demonstrates that in spite of highly conserved phenotype and function between mice, rat and humans, the distribution of ILC subsets in the intestinal mucosa is species-dependent, likely in response to both genetic and environmental factors.
Project description:Innate lymphoid cells (ILCs) have emerged as essential players in the skin-associated immune system in health and inflammatory skin diseases. Their low numbers and lack of specific markers hampered extensive characterization and consequently resulted in limited knowledge of their protein expression. Here, we combined flow cytometry and state-of-the-art proteomics to comprehensively describe the proteins constitutively expressed by ILC2 and ILC3 subsets derived from healthy human skin and peripheral blood. We quantified 6666 proteins from skin ILC and identified 608 differentially expressed proteins in the investigated subsets. In addition to the current analyses, highlighting new functions of ILC, the ILC proteomic libraries and the proteomes of the ILC2 and ILC3 subsets will serve as valuable resources for future analyses of ILC function and are available at http://skin.science.
Project description:The impact of the microenvironment on innate lymphoid cell (ILC)-mediated immunity in humans remains largely unknown. Here we used full-length Smart-seq2 single-cell RNA-sequencing to unravel tissue-specific transcriptional profiles and heterogeneity of CD127+ ILCs across four human tissues. Correlation analysis identified gene modules characterizing the migratory properties of tonsil and blood ILCs, and signatures of tissue-residency, activation and modified metabolism in gut and lung ILCs. Trajectory analysis revealed potential differentiation pathways from circulating and tissue-resident naïve ILCs to a spectrum of mature ILC subsets. In the lung we identified both CRTH2+ and CRTH2- ILC2 with lung-specific signatures, which could be recapitulated by alarmin-exposure of circulating ILC2. Finally, we describe unique TCR-V(D)J-rearrangement patterns of blood ILC1-like cells, revealing a subset of potentially immature ILCs with TCR-d rearrangement. In summary, we provide publicly available data as a resource for in-depth understanding of ILC-mediated immunity in humans, with implications for disease.
Project description:Tissue-resident innate lymphoid cells (ILCs) help sustain barrier function and respond to local signals. ILCs are traditionally classified as ILC1, ILC2 or ILC3 on the basis of their expression of specific transcription factors and cytokines1. In the skin, disease-specific production of ILC3-associated cytokines interleukin (IL)-17 and IL-22 in response to IL-23 signalling contributes to dermal inflammation in psoriasis. However, it is not known whether this response is initiated by pre-committed ILCs or by cell-state transitions. Here we show that the induction of psoriasis in mice by IL-23 or imiquimod reconfigures a spectrum of skin ILCs, which converge on a pathogenic ILC3-like state. Tissue-resident ILCs were necessary and sufficient, in the absence of circulatory ILCs, to drive pathology. Single-cell RNA-sequencing (scRNA-seq) profiles of skin ILCs along a time course of psoriatic inflammation formed a dense transcriptional continuum—even at steady state—reflecting fluid ILC states, including a naive or quiescent-like state and an ILC2 effector state. Upon disease induction, the continuum shifted rapidly to span a mixed, ILC3-like subset also expressing cytokines characteristic of ILC2s, which we inferred as arising through multiple trajectories. We confirmed the transition potential of quiescent-like and ILC2 states using in vitro experiments, single-cell assay for transposase-accessible chromatin using sequencing (scATAC-seq) and in vivo fate mapping. Our results highlight the range and flexibility of skin ILC responses, suggesting that immune activities primed in healthy tissues dynamically adapt to provocations and, left unchecked, drive pathological remodelling.
Project description:We find that the expression of GATA3 in skin ILCs is significantly lower than in conventional ILC2s of other tissues, indicating that the regulatory role of GATA3 may be different. Indeed, skin ILCs are still maintained after inducing Gata3 depletion in Gata3fl/flCreERT2 mice, when all ILC2s were gone. In addition, about 70% skin ILCs are found to experience RORγt expression as reflected by RORγt fate-mapping. And, conditional Gata3 depletion in the RORγt fate-mapped skin ILCs does not affect their number as well. Therefore, in contrast to conventional ILC2s, GATA3 is not required for skin ILCs for their maintenance. The RORγt fate-mapped skin ILCs have exhibited ILC3-like features. Single-cell transcriptome analysis further reveals that skin ILCs converge on a Ccr6+ ILC3-like state and an Il1rl1+ ILC2-like state. The regulatory role of GATA3 is crucial in the ILC3-like skin ILCs. It promotes the expression of their featured genes, while suppresses the expression of ILC2-like skin ILC featured genes. These ILC3-like skin ILCs locate in close proximity to hair follicles. During hair follicle recycling they migrate from isthmus to suprabulbar to promote the hair follicle growth. Whereas in absence of Gata3, the ILC3-like skin ILCs exhibit defective migration to the suprabulbar and reduced expression of the featured genes in this process. Together, our study evidence that skin ILCs are alternative to conventional ILC2s. In particular, we shed light on the function of GATA3 in promoting the specific gene expression in ILC3-like skin ILCs and regulating their crucial roles in hair follicle recycling, which will improve our knowledge about the involvement of ILCs in maintaining homeostasis of skin.
Project description:Innate lymphoid cells (ILCs) play a critical role in maintaining intestinal health in homeostatic and diseased conditions. During C. difficile infection (CDI), IL-33 activates ILC2 to protect from colonic damage and mortality. The function of IL-33 and ILC is tightly regulated by the intestinal microbiota. We set out to determine the impact of antibiotic-induced disruption of the microbiome on ILC function. Our goal was to understand antibiotic-induced changes in ILC function on susceptibility to C. difficile colitis in a mouse model. We utilized high-throughput single-cell RNAseq to investigate the phenotypic features of colonic ILC at baseline, after antibiotic administration with or without IL-33 treatment. We identified a heterogeneous landscape of colonic ILCs with gene signatures of inflammatory, anti-inflammatory, migratory, progenitor, plastic, and antigen-presenting ILC. Antibiotic treatment decreased ILC2 while coordinately increasing ILC1 and ILC3 phenotypes. Notably, Ifng+, Ccl5+, and Il23r+ ILC increased after antibiotics. IL-33 treatment counteracted the antibiotic effect by downregulating ILC1 and ILC3 and activating ILC2. In addition, IL-33 treatment markedly induced the expression of type 2 genes, including Areg and Il5. Finally, we identified amphiregulin, produced by ILC2, as protective duringC. difficileinfection. Together, our data expand our understanding of how antibiotics induce susceptibility to C. difficile colitis through their impact on ILC subsets and function.
Project description:Innate lymphoid cells (ILCs) reside in mucosal surfaces to potentiate immune responses, sustain mucosal integrity and maintain tissue homeostasis. However, how tumor infiltrating ILCs modulate tumor development and progression is unclear. Here we profiled tumor infiltrating ILCs during colorectal cancer (CRC) progression by single-cell RNA sequencing. We identified six clusters of tumor infiltrating ILCs with unique features. ILC1s expressed inhibitory receptors and underwent inhibitory functional conversion at the late stage of CRC. ILC2s were classified into three subsets (called ILC2-A, -B, -C), ILC2-C subset could facilitate tumor progression. HS3ST1 and PD1 were highly expressed in ILC2s of late stage CRC tumors and deficiency of HS3ST1 or PD1 in ILC2s suppressed tumor growth. Moreover, ILC3s transdifferentiated into ILCregs during CRC progression and ILCregs promoted tumor growth. Of note, TGF- signaling initiated the conversion of ILC3s to ILCregs and blockade of TGF- signaling could disrupt the ILCreg transdifferentiation and inhibited tumor growth as well. Thus intervention of ILC conversions might be a potential strategy for CRC immunotherapy.
Project description:Small intestinal innate lymphoid cells (ILCs) are known to regulate intestinal epithelial cell homeostasis and to help prevent pathogenic bacterial infections, by producing IL-22. However, other functions of these cells and the lineal relationship between ILCs and lymphoid or myeloid cells have not been clear. We performed a global gene expression analysis to examine which genes are highly expressed by small intestinal ILCs (Lin-c-Kit+Sca-1- cells) compared with non-ILCs (Lin-c-Kit-Sca-1- cells). To examine the gene expression profiles of ILCs within the small intestinal lamina propria (LP), we isolated Lingeage (Lin)-c-Kit+Sca-1- cells [consisting of NKp46+ ILC22 (Lin-c-Kit+Sca-1-NKp46+ cells) and LTi-like ILC (Lin-c-Kit+Sca-1-CD4+ cells)] as the ILC population, and Lin-c-Kit-Sca-1- cells as the non-ILC population, from the small intestinal LP of 8 week-old mice by FACS, then compared the gene expression profiles between these two populations by microarray analysis.
Project description:Innate lymphoid cells (ILCs) are able to directly respond to alarmin signals and produce an array of effector molecules for immune protection and tissue homeostasis. However, how posttranscriptional machinery in ILCs execute extracellular stimuli towards robust gene expression is yet to understand. Here, we reported a cell type-specific role of N6-methyladenosine (m6A) RNA methylation in ILCs. Inducible deletion of m6A methyltransferase METTL3 had little impact on ILC maintenance in the steady state or cytokine-induced ILC1 or ILC3 activation, but dramatically diminished IL-25-triggered ILC2 response. Specific deletion of Mettl3 in ILC2 significantly attenuated cell expansion, cytokine production, inter-organ migration, and anti-helminth immunity. To investigate the molecular mechanism by which m6A modification regulates ILC2 response, we subjected ILC2 of WT and Mettl3 Klrg1Cre mice to a m6A-tagged mRNA immunoprecipitation sequencing (meRIP-seq) to identify the m6A modified mRNA.