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 (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) are critical modulators of mucosal immunity, inflammation, and tissue homeostasis, but their full spectrum of cellular states and regulatory landscapes remain elusive. Here, we use a combination of genome-wide RNA-seq, ChIP-seq and ATAC-seq to compare the transcriptional and epigenetic identity of small intestinal ILCs, identifying thousands of distinct gene profiles and regulatory elements. Single-cell RNA-seq, cytometry, and imaging analyses reveal functional compartmentalization of cytokine expression and metabolic activity within the three classical ILC subtypes, and highlight transcriptional states beyond the current canonical classification. In addition, using antibiotic intervention and germ-free mice, we characterize the effect of the microbiome on the ILC regulatory landscape, and determine the response of ILCs to microbial colonization at the single-cell level. Together, our work characterizes the spectrum of transcriptional identities of small intestinal ILCs and describes how ILCs differentially integrate signals from the microbial microenvironment to generate phenotypic and functional plasticity.
Project description:Innate lymphoid cells (ILCs) are critical modulators of mucosal immunity, inflammation, and tissue homeostasis, but their full spectrum of cellular states and regulatory landscapes remain elusive. Here, we use a combination of genome-wide RNA-seq, ChIP-seq and ATAC-seq to compare the transcriptional and epigenetic identity of small intestinal ILCs, identifying thousands of distinct gene profiles and regulatory elements. Single-cell RNA-seq, cytometry, and imaging analyses reveal functional compartmentalization of cytokine expression and metabolic activity within the three classical ILC subtypes, and highlight transcriptional states beyond the current canonical classification. In addition, using antibiotic intervention and germ-free mice, we characterize the effect of the microbiome on the ILC regulatory landscape, and determine the response of ILCs to microbial colonization at the single-cell level. Together, our work characterizes the spectrum of transcriptional identities of small intestinal ILCs and describes how ILCs differentially integrate signals from the microbial microenvironment to generate phenotypic and functional plasticity.