Project description:Group 2 Innate Lymphoid Cells (ILC2s) are key players in type 2 immunity and contribute to maintaining homeostasis and responding to inflammation. ILC2s are implicated in the development of type 2 inflammation-mediated chronic disorders like asthma. While memory ILC2s have been identified in mouse, it is unknown whether human ILC2s can acquire immunological memory. Here, we demonstrate the persistence of CD45RO, a marker previously linked to inflammatory ILC2s, in resting ILC2s that have undergone prior activation. A high proportion of these cells concurrently reduce the expression of the canonical ILC marker CD127 in a tissue specific manner. Through isolation and in vitro stimulation of CD127- CD45RO+ ILC2s, we observed an augmented ability to proliferate and produce cytokines. CD127- CD45RO+ ILC2s are found in both healthy and inflamed tissues and display a gene signature of cell activation. Our findings suggest that human ILC2s can acquire innate immune memory and warrants a revision of the current strategies to identify human ILC2s.
Project description:Background: Alternaria exposure is associated with severe asthma in humans. Alternaria exposure in mice potently activates group 2 innate lymphoid cells (ILC2s) via the IL-33/ST2 axis and causes ILC2s to robustly secrete type 2 cytokines. Objective: Our aim was to determine whether conventionally used ILC2 markers, ST2 (IL-33R) and CD127 (IL-7Ra), were sufficient to identify all Th2-cytokine producing ILCs after Alternaria exposure. Methods: Mice received intranasal Alternaria for three days prior to analysis. Lung ILCs were identified by flow cytometry as CD45+Lineage−Thy1.2+ lymphocyte-sized cells, divided into four subsets based on ST2 and CD127 expression, and stained for intracellular cytokines and transcription factors. Sort-purified ILC subpopulations were also analyzed by RNA sequencing and qPCR. Results: Alternaria exposure led to accumulation of all ILC populations regardless of ST2 or CD127 expression. Nearly half of the GATA-3+, IL-5+, and IL-13+ ILCs were “unconventional” as they were either single or double negative for ST2/CD127. Further, these populations upregulated CD25, KLRG1, and ICOS after Alternaria challenge. Some activated unconventional IL-5+ ILC2s also produced IFNγ and IL-17A. In addition to shared ILC2 transcripts (Gata3, Il5, Il13) in all populations, RNA-seq further identified novel transcripts enriched in each subset. Finally, transcripts from all populations that correlated best with IL-5 and IL-13 production included Tnfrsf18, Ffar2, and Pde4b. Conclusions: Unconventional ST2- and CD127-negative mouse lung ILC2 populations are induced by Alternaria. Thus, commonly used lung ILC2 identification methods based on ST2 and CD127 do not accurately account for the total ILC2 burden and may exclude nearly half of these cells.
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:Transcriptomes of ILC2s sorted as KLRG1+CD127+CD90+Lin-CD45+ cells from mesenteric lymph nodes of non-treated mice were analyzed. The mice were part of the experiments described in PMID: 29496881 and were sequenced together with samples submitted in GSE108884.
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.
Project description:We analyzed the total proteome of group 2 innate lymphoid cells (ILC2s) after different stimulation with interleukin-33 (IL-33), a cytokine playing a critical role in human asthma, and TL1A, a TNF-family cytokine also known to activate ILC2s. Upon combined stimulation with IL-33 plus TL1A, we show that lung ILC2s produce high amounts of IL-9 and acquire a transient ‘ILC9’ phenotype. This phenotype is characterized by simultaneous production of large amounts of type 2 cytokines (IL-5, IL-13 and IL-9), induction of the IL-2 receptor CD25 (Il2ra), and of the transcription factors IRF4, JunB and BATF, that form immune-specific complexes known to induce IL-9 expression.
Project description:To determine the activation patterns of ILC2s and associated ILC2-intrinsic functional molecules triggered by the high fiber diet, we administered either a control or high fiber diet in WT mice and performed RNA sequencing of FACS-sorted ILC2s from mouse colons. RNAseq libraries were prepared from 1,000 sorted colonic lamina propria ILC2s (CD45+Lin-CD90.2+CD127+KLRG1+) by the Epigenomics Core at WCM using the Clontech SMARTer® Ultra® Low Input RNA Kit V4 (Clontech Laboratories). Libraries were sequenced on an Illumina HiSeq 2500, generating 50 bp single-end reads. Two samples from two control diet-fed WT SPF mice and two samples from two high fiber diet-fed WT SPF mice were used.
Project description:Group 2 innate lymphoid cells (ILC2s) reside in multiple tissues including lymphoid organs and barrier surfaces, and secrete type 2 cytokines including interleukin (IL)-5, IL-9 and IL-13. These cells participate in multiple physiological processes including allergic inflammation, tissue repair, metabolic homeostasis and host defense against helminth infections. Recent studies indicate that neuropeptides can play an important role in regulating ILC2 responses, however, the mechanisms that underlie these processes in vivo remain incompletely defined. Here, we identify that activated ILC2s upregulate choline acetyltransferase (ChAT)—the enzyme responsible for the biosynthesis of acetylcholine (ACh)—following infection with the helminth parasite Nippostrongylus brasiliensis or treatment with alarmins or cytokines including IL-25, IL-33 and thymic stromal lymphopoietin (TSLP). ILC2s also express acetylcholine receptors (AChRs), and ACh administration promotes ILC2 cytokine production and elicits expulsion of helminth infection. In accordance with this, ChAT deficiency in ILC2s leads to defective ILC2 responses and impaired immunity against helminth infection. Together, these results reveal a previously unrecognized role of the ChAT-ACh pathway in promoting type 2 innate immunity to helminth infection.
Project description:Single cell transcriptomic analysis of human CD25+ CD127- CD4+ Treg cells and CD25- CD127+ CD4+ Tconv cells isolated from peripheral blood from two different donors