Multiomic Single Cell Evaluation Reveals Inflammatory Cytokines Affect Innate Lymphoid Cell Fate After Allogeneic Stem Cell Transplantation [ATAC-Seq]
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ABSTRACT: Although allogeneic hematopoietic stem cell transplantation (alloHSCT) is the preferred treatment for a variety of hematologic malignancies, its use is limited by the development of acute graft-versus-host disease (aGvHD). Type II innate lymphoid cells (ILC2s) are immune cells that play an important role in maintaining homeostasis in mucosal tissues. Previous work has shown that ILC2 cells fail to reconstitute after chemotherapy or stem cell transplantation, though the mechanism for this finding is unclear, making delineation of the mechanisms involved in their turnover and reconstitution could have a significant impact on transplant outcomes. We evaluated the hypothesis that the loss of ILC2 cells post-transplant induced epigenetic changes that convert ILC2 cells to ILC1-like cells. Strikingly, single-cell, multiomic analysis of donor-derived ILC2s after transplantation revealed a previously unreported population of ILC1-like cells that differentiate from ILC2s in the small intestine lamina propria (exILC2s). To recapitulate this transdifferentiation, we modeled skewing of ILC2s in vitro with IL-12, IL-1b, and IL-18 (termed proinflammatory cytokine conditioned ILC2s, pcILC2s) and observed a reduction in Type 2 lineage-defining regulatory factors and the acquisition of proinflammatory Type 1 characteristics consistent with the phenotype and function of the exILC2s recovered post-transplant. Excitingly, our approach confirms the skewed cell population expresses ILC1 associated Tbx21 and reveals Nr4a2, Foxo1, and Fli1 as additional putative drivers of the emergent ILC1-like exILC2s after alloHSCT. To test whether ex vivo generated pcILC2s contribute to aGVHD-mediated mortality, we infused transdifferentiated donor WT or pcILC2s and measured the clinical score and survival of recipient mice after alloHSCT in a mismatched murine model. Unlike their unmanipulated WT ILC2 counterparts, our pcILC2s accelerated morbidity and mortality. Finally, peripheral blood cells from human patients with aGvHD have an altered chromatin landscape at ILC2-associated regions of accessibility compared to transplanted controls. These data demonstrate that following transplantation ILC2s convert to a pro-pathogenic population ILC1-like cell state. These findings provide novel insights into the contribution of ILC plasticity to mucosal dysregulation and aGvHD pathogenesis after alloHSCT in a murine model and may inform new approaches for modulating innate lymphocytes in human disease.
Project description:Although allogeneic hematopoietic stem cell transplantation (alloHSCT) is the preferred treatment for a variety of hematologic malignancies, its use is limited by the development of acute graft-versus-host disease (aGvHD). Type II innate lymphoid cells (ILC2s) are immune cells that play an important role in maintaining homeostasis in mucosal tissues. Previous work has shown that ILC2 cells fail to reconstitute after chemotherapy or stem cell transplantation, though the mechanism for this finding is unclear, making delineation of the mechanisms involved in their turnover and reconstitution could have a significant impact on transplant outcomes. We evaluated the hypothesis that the loss of ILC2 cells post-transplant induced epigenetic changes that convert ILC2 cells to ILC1-like cells. Strikingly, single-cell, multiomic analysis of donor-derived ILC2s after transplantation revealed a previously unreported population of ILC1-like cells that differentiate from ILC2s in the small intestine lamina propria (exILC2s). To recapitulate this transdifferentiation, we modeled skewing of ILC2s in vitro with IL-12, IL-1b, and IL-18 (termed proinflammatory cytokine conditioned ILC2s, pcILC2s) and observed a reduction in Type 2 lineage-defining regulatory factors and the acquisition of proinflammatory Type 1 characteristics consistent with the phenotype and function of the exILC2s recovered post-transplant. Excitingly, our approach confirms the skewed cell population expresses ILC1 associated Tbx21 and reveals Nr4a2, Foxo1, and Fli1 as additional putative drivers of the emergent ILC1-like exILC2s after alloHSCT. To test whether ex vivo generated pcILC2s contribute to aGVHD-mediated mortality, we infused transdifferentiated donor WT or pcILC2s and measured the clinical score and survival of recipient mice after alloHSCT in a mismatched murine model. Unlike their unmanipulated WT ILC2 counterparts, our pcILC2s accelerated morbidity and mortality. Finally, peripheral blood cells from human patients with aGvHD have an altered chromatin landscape at ILC2-associated regions of accessibility compared to transplanted controls. These data demonstrate that following transplantation ILC2s convert to a pro-pathogenic population ILC1-like cell state. These findings provide novel insights into the contribution of ILC plasticity to mucosal dysregulation and aGvHD pathogenesis after alloHSCT in a murine model and may inform new approaches for modulating innate lymphocytes in human disease.
Project description:Although allogeneic hematopoietic stem cell transplantation (alloHSCT) is the preferred treatment for a variety of hematologic malignancies, its use is limited by the development of acute graft-versus-host disease (aGvHD). Type II innate lymphoid cells (ILC2s) are immune cells that play an important role in maintaining homeostasis in mucosal tissues. Previous work has shown that ILC2 cells fail to reconstitute after chemotherapy or stem cell transplantation, though the mechanism for this finding is unclear, making delineation of the mechanisms involved in their turnover and reconstitution could have a significant impact on transplant outcomes. We evaluated the hypothesis that the loss of ILC2 cells post-transplant induced epigenetic changes that convert ILC2 cells to ILC1-like cells. Strikingly, single-cell, multiomic analysis of donor-derived ILC2s after transplantation revealed a previously unreported population of ILC1-like cells that differentiate from ILC2s in the small intestine lamina propria (exILC2s). To recapitulate this transdifferentiation, we modeled skewing of ILC2s in vitro with IL-12, IL-1b, and IL-18 (termed proinflammatory cytokine conditioned ILC2s, pcILC2s) and observed a reduction in Type 2 lineage-defining regulatory factors and the acquisition of proinflammatory Type 1 characteristics consistent with the phenotype and function of the exILC2s recovered post-transplant. Excitingly, our approach confirms the skewed cell population expresses ILC1 associated Tbx21 and reveals Nr4a2, Foxo1, and Fli1 as additional putative drivers of the emergent ILC1-like exILC2s after alloHSCT. To test whether ex vivo generated pcILC2s contribute to aGVHD-mediated mortality, we infused transdifferentiated donor WT or pcILC2s and measured the clinical score and survival of recipient mice after alloHSCT in a mismatched murine model. Unlike their unmanipulated WT ILC2 counterparts, our pcILC2s accelerated morbidity and mortality. Finally, peripheral blood cells from human patients with aGvHD have an altered chromatin landscape at ILC2-associated regions of accessibility compared to transplanted controls. These data demonstrate that following transplantation ILC2s convert to a pro-pathogenic population ILC1-like cell state. These findings provide novel insights into the contribution of ILC plasticity to mucosal dysregulation and aGvHD pathogenesis after alloHSCT in a murine model and may inform new approaches for modulating innate lymphocytes in human disease.
Project description:Type II innate lymphoid cells (ILC2s) maintain homeostasis and barrier integrity in mucosal tissues. Previous work has shown that in mice and humans, ILC2s fail to reconstitute after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Determining the mechanisms involved in their impaired reconstitution could improve transplant outcomes. By integrating chromatin and transcriptomic analysis of marked, transplanted ILC2s at the single cell level, we identify a previously unreported population of converted ILC1-like cells in the small intestine post-transplant. Exposure of ILC2s to proinflammatory cytokines in vitro results in a mixed ILC1-ILC2 phenotype but was able to convert only an extremely small population of ILC2s to ILC1s as observed in vivo. Whereas ILC2s protected against acute graft-versus-host disease (aGVHD) mediated-morbidity and mortality, infusion of proinflammatory cytokine-exposed ILC2s accelerated aGvHD. Finally, circulating peripheral blood mononuclear cells from patients with aGvHD have an altered ILC2-associated chromatin landscape compared to transplanted controls. These data demonstrate, for the first time, that ILC2s fail to repopulate their protective niche after allo-HSCT in part due to conversion to a pro-pathogenic population marked by an ILC1-like chromatin state, providing novel insights into the contribution of ILC plasticity to aGvHD pathogenesis after allo-HSCT.
Project description:Type-2 innate lymphoid cells (ILC2s) promote anti-helminth responses and contribute to allergies. Though Bcl11b has been previously considered a T-lineage identity transcription factor (TF) that restrains the innate-cell genetic programs, we report here that Bcl11b is highly expressed in mature ILC2s and acts upstream of the key ILC2 TFs Gfi1, Gata-3, and of IL-33 receptor IL1rl1 (T1ST2). Additionally, Bcl11b-/- ILC2s de-repressed Rorγt, Ahr and IL-23 receptor, normally expressed in type-3 ILCs (ILC3s). Consequently, Bcl11b-/- ILC2s lost ILC2 functions and gained ILC3 functions, expanding in response to the protease allergen papain, however producing IL-17 and IL-22, and not IL-5 and IL-13, causing lung neutrophilia rather than eosinophilia, and diminished mucus production. Our results broaden Bcl11b's role from a T-cell only TF, and establishes that Bcl11b sustains mature ILC2 genetic and functional programs and lineage fidelity through positive regulation of essential ILC2 TFs and negative regulation of pivotal ILC3 TFs. RNA-seq analysis on sorted ILC2s from the mLNs of Bcl11bF/F Cre-ERT2 and wildtype mice at steady state following tamoxifen mediated deletion of Bcl11b
Project description:ILC2 cells are a newly described cell type whose biology and contribution to disease are poorly understood. ILC2 cells are activated by allergens, viral infection, and/or epithelial damage via IL-33 and IL-25. ILC2 cells require IL-2, IL-7, IL-25 and IL-33 for their survival and expansion. In mice, ILC2s produce multiple mediators primarily associated with type 2 inflammation (IL-13, IL-5, IL-4, IL-6, IL-9, IL-10, GM-CSF, amphiregulin). ILC2 cells may contribute to the pathology of asthma through multiple mediators that include IL-13-independent pathways. Our goal is to compare transcriptional profiles of IL-33- or IL-25-activated ILC2 cells from blood to characterize these cells and to identify marker(s) that can be utilized to detect them in human tissue. ILC2 cells (Lineage negative, CRTH2+, CD161+, CD127+) were purified from human blood of 5 different donors by flow cytometry. The ILC2 yield ranged from 20,000 to 165,000 cells per donor (0.001-0.008% WBC). Purified ILC2s were expanded in vitro in the presence of IL-2, IL-7, IL-33 and IL-25 (each at 50 ng/ml) for 7-10 days. Expanded cells maintained the ILC2 phenotype (Lineage negative, CRTH2+, CD161+, CD127+). The cells were rested for 2 days in the presence of 1 ng/ml IL-2 and IL-7 and then treated in the presence of 1 ng/ml IL-2 and IL-7 with either media control, IL-25 (50 ng/ml), IL-33 (50 ng/ml), and/or TSLP (50 ng/ml) in combination, for 6 or 24 hours. Whole RNA was isolated via the RNeasy kit (Qiagen). Stratagene Universal Human Reference RNA was used as the reference.
Project description:Group 2 innate lymphoid cells (ILC2s) are linked to type 2 immune diseases but can also molecularly change phenotype and provide type 1 immunity towards pathogens. Here we identify an ILC2 subset which can convert into IL-17 producing NKp44‒ ILC3-like cells. c-Kit and CCR6 define this ILC2 subpopulation which exhibit ILC3 features, including RORγt, which enables the conversion into IL-17 producing cells in response to IL-1β and IL-23. We also report a novel but critical role for TGF-β in promoting the conversion of c-kit‒ ILC2s into RORγt expressing c-Kit+ ILC2s by inducing the upregulation of IL23R, CCR6 and KIT mRNA in these cells. This switch was dependent on RORγt and down-regulation of GATA-3. IL-4 was able to reverse this event supporting a role for this cytokine in maintaining ILC2 identity. Notably, this plasticity has physiological relevance as a subset of RORγt+ ILC2s express the skin homing receptor CCR10 and the frequencies of IL-17‒producing ILC3s are increased at the expense of ILC2s within the lesional skin of psoriatic patients compared to healthy individuals.
Project description:Innate lymphoid cell (ILC) subsets that mirror helper T cells in their effector cytokine profiles have recently emerged as central players in both homeostatic and inflammatory conditions. Like their Th1, Th2 and Th17/Th22 helper T cell counterparts, ILC subsets are categorized based on their expression of specific transcription factors and effector cytokines: group 1 ILC (ILC1) express T-bet and IFN-γ; group 2 ILC (ILC2) express GATA-3 and type 2 effector cytokines such as IL-13 and IL-5; and group 3 ILC (ILC3) express RORgt and the cytokines IL-22 and/or IL-17. Under this nomenclature, natural killer (NK) cells and lymphoid tissue inducers (LTi) are considered ILC1 and ILC3, respectively. ILC1 contain both CD4+ and CD4- populations, but whether this phenotypic characteristic reflects functional differences between these two populations is unknown. These studies examine the gene expression profiles of CD4+ vs CD4- ILC1 in a cohort of healthy control subjects. ILC subsets were isolated from the peripheral blood of healthy control subjects. cDNA was isolated and amplified from sorted populations, and gene expression was analyzed by RNAseq
Project description:Group 2 innate lymphoid cells (ILC2s) in the lung are stimulated by inhaled allergens. ILC2s do not directly recognize allergens but they are stimulated by cytokines including interleukin (IL)-33 released by damaged epithelium.Lung ILC2s, upon stimulation, produce T helper 2 cell-type cytokines inducing T cell independent allergic lung inflammation. We now report that lung ILC2s, upon activation by an allergen or IL-33, acquire the properties of memory cells. The activated ILC2s initially proliferate and secrete cytokines, followed by a contraction phase as they stop producing cytokines. Nevertheless, some persist long after the resolution of the inflammation and acquire intrinsic capacities to react to unrelated allergens more vigorously than naïve ILC2s, thus mediating a severe allergic lung inflammation. Gene expression profiles of the previously activated ILC2s show a gene signature of memory T cells. These antigen non-specific memory ILC2s may explain why asthma patients are often sensitized to multiple allergens. ILC2s were isolated from mouse lungs from naive and IL-33 injected mice 4 days, 14 days and 4 months after the initial treatment. RNA was extracted from those ILC2 populations and analyzed for gene expression profiles. RNA was also extracted from ILC2s isolated from lung draining mediastinal lymph node (mLN) 4 days and 14 days after IL-33 treatment.
Project description:Innate lymphoid cells (ILCs) are tissue-resident lymphocytes subdivided into ILC1s, ILC2s and ILC3s based on core regulatory programs and signature cytokines secreted. ILCs exhibit functional plasticity: for instance, human IL-22-producing ILC3s convert into IFN-γ-producing ILC1-like in vitro. Whether this conversion occurs in vivo is unclear. Using flow cytometry, mass cytometry and scRNAseq, here we found that ILC3s and ILC1s occupy opposite ends of a spectrum including discrete subsets in human tonsils. RNA velocity suggested strong directionality toward ILC1s for one ILC3-ILC1 intermediate cluster. Clonal analysis revealed graded ability of ILC3-ILC1 subsets to convert into ILC1-like cells. When examined in humanized mice, ILC3 acquisition of ILC1 features showed tissue-dependency. In chromatin studies, Aiolos emerged as a nuclear factor that cooperates with Tbet to repress evolutionarily conserved regulatory elements active in ILC3s. The human intestine also exhibited an ILC3–ILC1 transitional population. We conclude that conversion of ILC3s to ILC1-like occurs in vivo in human tissues, and that tissue factors and Aiolos are crucial for this process.
Project description:Innate lymphoid cells (ILCs) are tissue-resident lymphocytes subdivided into ILC1s, ILC2s and ILC3s based on core regulatory programs and signature cytokines secreted. ILCs exhibit functional plasticity: for instance, human IL-22-producing ILC3s convert into IFN-γ-producing ILC1-like in vitro. Whether this conversion occurs in vivo is unclear. Using flow cytometry, mass cytometry and scRNAseq, here we found that ILC3s and ILC1s occupy opposite ends of a spectrum including discrete subsets in human tonsils. RNA velocity suggested strong directionality toward ILC1s for one ILC3-ILC1 intermediate cluster. Clonal analysis revealed graded ability of ILC3-ILC1 subsets to convert into ILC1-like cells. When examined in humanized mice, ILC3 acquisition of ILC1 features showed tissue-dependency. In chromatin studies, Aiolos emerged as a nuclear factor that cooperates with Tbet to repress evolutionarily conserved regulatory elements active in ILC3s. The human intestine also exhibited an ILC3–ILC1 transitional population. We conclude that conversion of ILC3s to ILC1-like occurs in vivo in human tissues, and that tissue factors and Aiolos are crucial for this process.