Project description:A transitory, interleukin-25-responsive, KLRG1high Group 2 innate lymphoid (ILC2) cell subset that migrates to mucosal tissues early during type-2 inflammation was recently identified. This study focuses on understanding the significance of this population in relation to tissue-resident ILC2 cells in the lung and intestine. RNA-sequencing and unbiased pathway analysis revealed the AP-1 factor BATF as a potential modulator of ILC2 cell fate. For RNAseq, KLRG1-postive and KLRG1-neagive populations were sorted and compared.
Project description:Subtypes of innate lymphoid cells (ILC), defined by effector function and transcription factor expression, have recently been identified. In the adult, ILC derive from common lymphoid progenitors in bone marrow, although transcriptional regulation of the developmental pathways involved remains poorly defined. TOX is required for development of lymphoid tissue inducer cells, a type of ILC3 required for lymph node organogenesis, and NK cells, a type of ILC1. We show here that production of multiple ILC lineages requires TOX, as a result of TOX-dependent development of common ILC progenitors. Comparative transcriptome analysis demonstrated failure to induce various aspects of the ILC gene program in the absence of TOX, implicating this nuclear factor as a key early determinant of ILC lineage specification. TOX KO vs. wild tyype
Project description:Innate lymphoid cells (ILC) in the small intestine govern immune homeostasis and protect the host against gut pathogens. While distinct cell-intrinsic signals have been identified that determine ILC development and differentiation, it has remained unclear which cell population regulates ILC sustenance. Using unbiased single cell RNA transcriptomic analysis of intestinal fibroblasts, we have identified a specialized Ccl19-expressing fibroblastic reticular cell (FRC) population that underpins solitary intestinal lymphoid tissue (SILT) structures including cryptopatches and isolated lymphoid follicles. Conditional ablation of lymphotoxin-β receptor (LTβR) signalling in SILT FRC impeded the maturation of isolated lymphoid follicles and blocked ILC maintenance through the downregulation of IL-7, consequently resulting in the elevated susceptibility to bacterial infection. Moreover, specific Ltbr ablation in FRC during adulthood revealed that constant LTβR-dependent FRC-ILC interaction is required to maintain SILT structures and ILC populations. Taken together, our study unveils a critical intestinal FRC niche that secures protective gut immunity.
Project description:Subtypes of innate lymphoid cells (ILC), defined by effector function and transcription factor expression, have recently been identified. In the adult, ILC derive from common lymphoid progenitors in bone marrow, although transcriptional regulation of the developmental pathways involved remains poorly defined. TOX is required for development of lymphoid tissue inducer cells, a type of ILC3 required for lymph node organogenesis, and NK cells, a type of ILC1. We show here that production of multiple ILC lineages requires TOX, as a result of TOX-dependent development of common ILC progenitors. Comparative transcriptome analysis demonstrated failure to induce various aspects of the ILC gene program in the absence of TOX, implicating this nuclear factor as a key early determinant of ILC lineage specification.
Project description:Innate lymphoid cells (ILC) in the small intestine govern immune homeostasis and protect the host against gut pathogens. While distinct cell-intrinsic signals have been identified that determine ILC development and differentiation, it has remained unclear which cell population regulates ILC sustenance. Using unbiased single cell RNA transcriptomic analysis of intestinal fibroblasts, we have identified a specialized Ccl19-expressing fibroblastic reticular cell (FRC) population that underpins solitary intestinal lymphoid tissue (SILT) structures including cryptopatches and isolated lymphoid follicles. Conditional ablation of lymphotoxin-β receptor (LTβR) signalling in SILT FRC impeded the maturation of isolated lymphoid follicles and blocked ILC maintenance through the downregulation of IL-7, consequently resulting in the elevated susceptibility to bacterial infection. Moreover, specific Ltbr ablation in FRC during adulthood revealed that constant LTβR-dependent FRC-ILC interaction is required to maintain SILT structures and ILC populations. Taken together, our study unveils a critical intestinal FRC niche that secures protective gut immunity.
Project description:Innate lymphoid cells (ILCs) promote lung inflammation in diseases such as asthma through cytokine production. RNA-binding proteins (RBPs) are critical post-transcriptional regulators of cellular function though the role of RBPs in innate lymphoid cells is unknown. Here, we demonstrate that RNA-binding motif 3 protein (RBM3) is one of the most highly expressed RBPs in Thy1.2+ lung ILCs after fungal allergen challenge and is further induced by epithelial cytokines TSLP and IL-33 in both human and mouse ILCs. Single (rbm3-/-) and double (rbm3-/-rag2-/-) knockout mice exposed via the airway to the asthma-associated fungal allergen Alternaria alternata displayed increases in eosinophilic lung inflammation and ILC activation compared to control mice. In addition to increased Th2 cytokine production, rbm3-/- ILCs produced elevated IL-17A. The negative regulation by RBM3 in ILC responses was direct as purified rbm3-/- ILCs were hyperinflammatory in vitro and in vivo after stimulation with IL-33. Transcriptomic analysis by RNA-sequencing of rbm3-/- lung ILCs showed increased type 2 and 17 cytokines as well as global expression differences in critical cytokines, receptors, transcription factors, and survival transcripts compared with WT ILCs. Importantly, these transcript changes were independent of the numbers of AU-rich elements (AREs) which RBM3 is known to bind. Thus, regulation of ILC responses by RNA-binding proteins offers novel mechanistic insight into lung ILC biology and ILC-driven inflammatory diseases.
Project description:Innate lymphoid cells (ILCs) develop from common lymphoid progenitors (CLP), which further differentiate into the common ILC progenitor (CILP) that can give rise to both ILCs and NK cells. Murine ILC intermediates have recently been characterized, but the human counterparts and their developmental trajectories have not yet been identified, largely due to the lack of homologous surface receptors in both organisms. Here, we show that human CILPs (CD34+CD117+α4β7+Lin-) acquire CD48 and CD52, which define NK progenitors (NKPs) and innate lymphoid cell precursors (ILCPs). Two distinct NK cell subsets were generated in vitro from CD34+CD117+α4β7+Lin-CD48-CD52+ and CD34+CD117+α4β7+Lin-CD48+CD52+ NKPs, respectively. Independent of NKPs, ILCPs exist in the CD34+CD117+α4β7+Lin-CD48+CD52+ subset and give rise to ILC1s, ILC2s and NCR+ ILC3s, whereas CD34+CD117+α4β7+Lin-CD48+CD52- ILCPs give rise to a distinct subset of ILC3s that have lymphoid tissue inducer (LTi)-like properties. Additionally, CD48 expressing CD34+CD117+α4β7+Lin- precursors give rise to tissue-associated ILCs in vivo. We also observed that the interaction of 2B4 with CD48 induced differentiation of ILC2s, and together these findings show that expression of CD48 by human ILCPs modulates ILC differentiation.
Project description:Innate lymphoid cells (ILCs) are a recently recognized heterogenous group of immune cells that are critical in orchestrating immunity and inflammation in the intestine, but whether ILCs influence immune responses or tissue homeostasis at other mucosal sites remains poorly characterized. Here we identify a population of lung-resident ILCs in mice and humans that expressed the alloantigen Thy-1 (CD90), interleukin 2 (IL-2) receptor a-chain (CD25), IL-7 receptor a-chain (CD127) and the IL-33 receptor subunit T1-ST2. Notably, mouse ILCs accumulated in the lung after infection with influenza virus, and depletion of ILCs resulted in loss of airway epithelial integrity, diminished lung function and impaired airway remodeling. These defects were restored by administration of the lung ILC product amphiregulin. Collectively, our results demonstrate a critical role for lung ILCs in restoring airway epithelial integrity and tissue homeostasis after infection with influenza virus. As part of this study, we performed gene expression profiling to examine how the transcriptional signatures compared between murine naïve group 2 lung ILC and group 3 splenic LTi cell populations. Group 2 ILCs from the lung (Lin- CD90+ CD25+ T1/ST2+) and Group 3 LTi cells from the spleen (Lin- CD90+ CD25+ CD4+) were sort-purified from naive wildtype C57BL/6 mice using BD FACS Aria. Four biological replicates were collected, each replicate containing 1.5 x 104 to 2 x104 cells sorted to a purity >97% from six pooled lungs (ILCs) or 10 pooled spleens (LTi cells). Cells were sorted directly into TRIzol LS (Invitrogen), then mRNA was isolated, amplified, labeled, and hybridized to Affymetrix GeneChip (Mouse Gene 1.0 ST).