ABSTRACT: Human ILCs are classically categorized into five subsets; cytotoxic CD127-CD94+ NK cells and non-cytotoxic CD127+CD94-, ILC1s, ILC2s, ILC3s and LTi cells. Here, we identify a novel subset within the CD127+ ILC population, characterized by the expression of the cytotoxic marker CD94. These CD94+ ILCs strongly resemble conventional ILC3s in terms of phenotype, transcriptome and cytokine production, but are highly cytotoxic. IL-15 was unable to induce differentiation of CD94+ ILCs towards mature NK cells. Instead, CD94+ ILCs retained RORγt, CD127 and CD200R expression and produced IL-22 in response to IL-15. Culturing non-cytotoxic CD127+ ILC1s or ILC3s with IL-12 induced upregulation of CD94 and cytotoxic activity, effects that were not observed with IL-15 stimulation. Thus, human helper ILCs can acquire a cytotoxic program without differentiating into NK cells.
Project description:Controversy in the identity and distinction of helper ILC1s and NK cells exist due to overlapping markers and the use of different gating strategies by distinct groups. Recently we identified cytotoxic ILC3s characterized by expression of CD94. Here we analyzed the full spectrum of CD127+ ILCs and NK cells in intestinal lamina propria from healthy donors and Crohn’s disease patients and identified two populations of CD127+CD94+ ILCs, designated A and B that could be distinguished on expression of CD117, CD18 and cytotoxic molecules. Population B highly expressed granulysin, a cytotoxic molecule linked to bacterial lysis and/or chemotaxis of monocytes. Granulysin protein was amply secreted by population B cells upon stimulation with IL-15. Activation of population B in the presence of TGF-β strongly reduced the expression of cytotoxic effector molecules of population B. Strikingly, samples from individuals that suffer from active Crohn disease displayed dramatically enhanced frequencies of granulysin expressing effector CD127+CD94+ ILCs compared to non-inflamed controls.
Project description:Type 3 innate lymphoid cells (ILC3s) fulfill protective functions at mucosal surfaces via cytokine production. While their plasticity to become ILC1s, the innate counterparts of type 1 helper T cells, has been described previously, we report that they can differentiate into cytotoxic lymphocytes with many characteristics of early differentiated natural killer (NK) cells. This transition is promoted by the proinflammatory cytokines IL-12 and IL-15, and correlates with expression of the master transcription factor of cytotoxicity eomesodermin (Eomes). As revealed by transcriptome analysis and flow cytometric profiling, differentiated ILC3s express CD94, NKG2A, NKG2C, CD56 and CD16 among other NK cell receptors, and possess all components of the cytotoxic machinery. These characteristics allow them to recognize and kill leukemic cells. Therefore, ILC3s can be harnessed for cytotoxic responses via differentiation under the influence of proinflammatory cytokines.
Project description:Innate lymphocytes are integral components of the cellular immune system that coordinates host defense against a multitude of challenges and can trigger immunopathology when dysregulated. Natural killer (NK) cells and innate lymphoid cells (ILCs) are innate immune effectors postulated to functionally mirror conventional cytotoxic T lymphocytes and helper T cells, respectively. Here, we show that the cytolytic molecule granzyme C was surprisingly expressed in cells with the phenotype of type 1 ILCs (ILC1s) in mouse liver and salivary gland. Cell fate-mapping and transfer studies revealed that granzyme C-expressing innate lymphocytes could be derived from ILC progenitors and did not interconvert with NK cells, ILC2s, or ILC3s. Granzyme C defined a maturation state of ILC1s, which required the transcription factor T-bet and to a lesser extent Eomes specifically in the salivary gland for their maintenance. Furthermore, transforming growth factor-b (TGF-b) signaling promoted maintenance of granzyme C-expressing ILC1s in the salivary gland and in the tumor of a transgenic breast cancer model, and their depletion caused accelerated tumor growth. ILC1s gained granzyme C expression following interleukin-15 (IL-15) stimulation, which enabled perforin-mediated cytotoxicity. Strikingly, constitutive activation of the IL-15-regulated transcription factor Stat5 in granzyme C-fate-mapped ILC1s triggered lethal perforin-dependent autoimmunity in neonatal mice. Thus, granzyme C marks a cytotoxic effector state of ILC1s, broadening their function beyond ‘helper-like’ lymphocytes.
Project description:GATA3 is indispensable for the development of all IL-7Rα-expressing innate lymphoid cells (ILCs) and maintenance of type 1 ILCs (ILC1s) and type 2 ILCs (ILC2s). However, the importance of low GATA3 expression in type 3 ILCs (ILC3s) is still elusive. Here, we report that GATA3 regulates homeostasis of ILC3s by controlling IL-7Rα expression. In addition, GATA3 is critical for the development of NKp46+ ILC3 subset partially through regulating the balance between T-bet and RORγt. Genome-wide analyses indicate that while GATA3 positively regulates CCR6+ and NKp46+ ILC3 subset-specific genes in respective lineages, it negatively regulates CCR6+ ILC3-specific genes in NKp46+ ILC3s. Furthermore, GATA3 regulates IL-22 production in both CCR6+ and NKp46+ ILC3s. Thus, low GATA3 expression is critical for the development and function of ILC3 subsets. To identify GATA3 regulated genes in total ILC3s with RNA-Seq; To identify unique genes expressed by CCR6+ ILC3 or NKp46+ ILC3 and GATA3 regulated genes within these two ILC3 subsets with RNA-Seq; To identify GATA3 direct binding sites in ILC3s, ILC2s and Th2 cells with ChIP-Seq.
Project description:GATA3 is indispensable for the development of all IL-7Rα-expressing innate lymphoid cells (ILCs) and maintenance of type 1 ILCs (ILC1s) and type 2 ILCs (ILC2s). However, the importance of low GATA3 expression in type 3 ILCs (ILC3s) is still elusive. Here, we report that GATA3 regulates homeostasis of ILC3s by controlling IL-7Rα expression. In addition, GATA3 is critical for the development of NKp46+ ILC3 subset partially through regulating the balance between T-bet and RORγt. Genome-wide analyses indicate that while GATA3 positively regulates CCR6+ and NKp46+ ILC3 subset-specific genes in respective lineages, it negatively regulates CCR6+ ILC3-specific genes in NKp46+ ILC3s. Furthermore, GATA3 regulates IL-22 production in both CCR6+ and NKp46+ ILC3s. Thus, low GATA3 expression is critical for the development and function of ILC3 subsets.
Project description:Group 1 innate lymphoid cells (ILCs) comprise a heterogeneous family of cytotoxic natural killer (NK) cells and ILC1s. We identifiy a population of “liver-type†ILC1s with transcriptional, phenotypic, and functional features distinct from those of conventional and liver-resident NK cells as well as from other previously described human ILC1 subsets. LT-ILC1s were CD49a+CD94+CD200R1+, expressed the transcription factor T-BET, do not express the activating receptor NKp80, or the transcription factor EOMES. Similar to NK cells, liver-type ILC1s produce IFN-γ, TNF-α, and GM-CSF; however, liver-type ILC1s also produce IL-2 and lack perforin and granzyme B. Liver- type ILC1s are expanded in cirrhotic liver tissues, and they can be produced from blood-derived ILC precursors in vitro in the presence of TGF-β1 and liver sinusoidal endothelial cells. Cells with similar signature and function can also be found in tonsil and intestinal tissues. Collectively, our study identifies and classifies a population of human cross-tissue ILC1s.
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.
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.