Parasitic helminths repress the canonical intestinal stem cell program
ABSTRACT: The intestinal helminth parasite Heligmosomoides polygyrus initiates infection in mice by penetrating the duodenal mucosa, where it develops while surrounded by a multicellular granulomatous infiltrate before emerging into the intestinal lumen. We examined early H. polygyrus infection to assess the epithelial response to disruption of the mucosal barrier. Unexpectedly, intestinal stem cell markers, including Lgr5 and Olfm4, were completely lost in crypts overlying larvae-associated granulomas. We sought to identify the mechanism by which the H. polygyrus granuloma represses the activity of intestinal stem cells. Overall design: CD45-negative EpCAM-positive CD44-positive crypt cells were sorted from duodenum of mice infected with H. polygyrus for six days. Crypt cells from granuloma punch biopsies was compared to crypt cells from non-granuloma punch biopsies.
Project description:The purpose of this study is to compare the cellular populations present within granuloma (Sca1+) and non-granuloma (Sca-1–) crypt epithelum arising from parasitic H polygyrus infections. Overall design: Single cell transcriptomes of Sca-1+(Granuloma) and Sca-1–(Non-granuloma) were generated from infected mice and then re-merged for population comparison
Project description:We show that a gastrointestinal nematode that infects mice, Heligmosomoides polygyrus, secretes vesicles packaged with specific microRNAs (miRNAs) and Y RNAs as well as a nematode-specific Argonaute protein. The vesicles are of intestinal origin and are enriched for homologs of mammalian proteins found in exosomes, including heat shock proteins, tetraspanins and an ESCORT protein. The nematode-derived vesicles are internalized by mouse intestinal epithelial cells and mediate changes in expression of host genes involved in inflammation and immunity, including the receptor for the alarmin IL33 as well as a key regulator of MAPK signaling, DUSP1. A total of 12 samples were analyzed, from 4 different conditions: medium, exosome-treated, LPS and LPS+exosomes, each with 3 biological replicates. One of the 'medium' replicates was discarded due to outlier behaviour.
Project description:Mouse bone marrow derived macrophages were stimulated with L3 larvae of the helminth Heligmosomoides polygyrus (Hp) (500 L3 /1 mio cells) in the presence or absence of immune serum (1:50 v:v) from challenge-Hp-infected mice.
Project description:Gene expression of Treg cells that have lost Foxp3 expression and acquired Il4 expression following adoptive transfer into T-cell deficient mice (HpTR-IL-4gfp+), cmpared to conventional Treg cells isolated from H. polygyrus-infected wild-type mice (HpTR) and Th2 cells generated from naïve T cells following adoptive transfer into H. polygyrus-infected T-cell deficient mice (nT-IL-4gfp+). Immunity to intestinal helminth infections requires the rapid activation of T helper 2 (Th2) cells. However, simultaneous expansion of regulatory CD4+Foxp3+ T (Treg) cells impedes protective responses, resulting in chronic infections. The ratio between regulatory and effector T cells can therefore determine the outcome of infection. The re-differentiation of Treg into T helper (Th) cells has been identified in hyper-inflammatory diseases. In this study, we asked whether ex-Treg Th2 cells develop and contribute to type 2 immunity. Using multi-gene reporter and fate-reporter systems we demonstrate that a significant proportion of Th2 cells derive from Foxp3+ cells following Heligmosomoides polygyrus infection and airway allergy. Ex-Foxp3 Th2 cells exhibit characteristic Th2 effector functions and provide immunity to H. polygyrus. Through selective deletion of Il4ra on Foxp3+ cells, we further demonstrate IL-4 is required for the development of ex-Foxp3 Th2 cells. Collectively, our findings indicate that converting Treg cells into Th2 cells could concomitantly enhance Th2 cells and limit Treg-mediated suppression. Overall design: Naïve T cells were FACS-sorted from naive wild-type mice. HpTR cells were FACS-sorted from H. polygyrus-infected mice. HpTR cells and nT cells were transferred to T-cell deficient mice infected with H. polygyrus. IL-4gfp-expressing cells were FACS-sorted from HpTR (HpTR-IL-4gfp+) or nT (nT-IL-4gfp+) recipients. 3 biological samples were obtained from 3 independent experiments for each sample group.
Project description:Immunity to intestinal helminth infections has been well studied, but the mechanism of helminth killing prior to expulsion remains unclear. Here we identify epithelial-cell-derived phospholipase A2 group 1B (PLA2g1B) as a host-derived endogenous anthelmintic. PLA2g1B is elevated in resistant mice and is responsible for killing tissue-embedded larvae. Despite comparable activities of other essential type-2-dependent immune mechanisms, Pla2g1b-/- mice failed to expel the intestinal helminths Heligmosomoides polygyrus or Nippostrongylus brasiliensis. Expression of Pla2g1b by epithelial cells was dependent upon intestinal microbiota, adaptive immunity, and common-gamma chain-dependent signaling. Notably, Pla2g1b was downregulated in susceptible mice and inhibited by IL-4R-signaling in vitro, uncoupling parasite killing from expulsion mechanisms. Resistance was restored in Pla2g1b-/- mice by treating infective H. polygyrus L3 larvae with PLA2g1B, which reduced larval phospholipid abundance. These findings uncover epithelial-cell-derived Pla2g1b as an essential mediator of helminth killing, highlighting a previously overlooked mechanism of anti-helminth immunity.
Project description:Celiac disease (CD) is a chronic immune-mediated disorder with an important genetic component. We analyzed the expression of candidate genes in biopsies from duodenum. Overall design: The sample set consisted of duodenal biopsies from 15 CD children at diagnosis (on a gluten-containing diet, with CD-associated antibodies, atrophy of intestinal villi and crypt hyperplasia), and the same patients in remission after being treated with gluten-free diet (GFD) for >2 years (asymptomatic, antibody negative, and normalized intestinal epithelium at that time), plus 15 tissue samples from non-celiac individuals not suffering from inflammation at the time of endoscopy, used as controls.