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Project description:The prostaglandin D2 receptor CRTH2 suppresses epithelial responses during intestinal helminth infection
| PRJNA625445 | ENA
Project description:Our earlier work showed that knockout of hematopoietic prostaglandin D synthase (HPGDS, an enzyme that produces prostaglandin D2) caused more adenomas in Apc(Min/+) mice. Conversely, highly expressed transgenic HPGDS allowed fewer tumors. Prostaglandin D2 (PGD2) binds to the prostaglandin D2 receptor known as PTGDR (or DP1). PGD2 metabolites bind to peroxisome proliferator-activated receptor γ (PPARG). We hypothesized that Ptgdr or Pparg knockouts may raise numbers of tumors, if these receptors take part in tumor suppression by PGD2. To assess, we produced Apc(Min/+) mice with and without Ptgdr knockouts (147 mice). In separate experiments, we produced Apc(Min/+) mice expressing transgenic lipocalin-type prostaglandin D synthase (PTGDS), with and without heterozygous Pparg knockouts (104 mice). Homozygous Ptgdr knockouts raised total numbers of tumors by 30-40% at 6 and 14 weeks. Colon tumors were not affected. Heterozygous Pparg knockouts alone did not affect tumor numbers in Apc(Min/+) mice. As mentioned above, our Pparg knockout assessment also included mice with highly expressed PTGDS transgenes. Apc(Min/+) mice with transgenic PTGDS had fewer large adenomas (63% of control) and lower levels of v-myc avian myelocytomatosis viral oncogene homolog (MYC) mRNA in the colon. Heterozygous Pparg knockouts appeared to blunt the tumor-suppressing effect of transgenic PTGDS. However, tumor suppression by PGD2 was more clearly mediated by receptor PTGDR in our experiments. The suppression mechanism did not appear to involve changes in microvessel density or slower proliferation of tumor cells. The data support a role for PGD2 signals acting through PTGDR in suppression of intestinal tumors.
| S-EPMC4303173 | biostudies-literature
Project description:Th2 cells must sense and adapt to the tissue milieu in order to provide protective host immunity and tissue repair. Here, we examined the mechanisms promoting Th2 cell differentiation and function within the small intestinal lamina propria. Single cell RNA-seq analyses of CD4+ T cells from the small intestinal lamina propria of helminth infected mice revealed high expression of the gene Epas1, encoding the transcription factor hypoxia-inducible factor 2a (HIF2α). In vitro, exposure to hypoxia or genetic HIF2α activation promoted Th2 cell differentiation, even under non-polarizing conditions. In mice, HIF2α activation in CD4+ T cells promoted intestinal Th2 cell accumulation in the absence of infection, and HIF2α-deficiency impaired CD4+ T cell-mediated host immunity to intestinal helminth infection. Our findings identified hypoxia, and the oxygen-regulated transcription factor Hypoxia-Inducible Factor 2α (HIF2α), as key regulators of Th2 cell differentiation and function within the small intestine.
2025-04-01 | GSE288268 | GEO
Project description:We report RNA sequencing data from the plantaris tendons of 3-month old Sprague Dawley rats that were treated with vehicle or GSK2894631A to inhibit the HPGDS enzyme. Rats underwent a bilateral plantaris tendon tear followed by immediate repair, and samples were obtained either 7 or 21 days after surgical intervention.
2019-09-20 | GSE130276 | GEO
Project description:1. The recombinant human prostaglandin D(2) (PGD(2)) receptor, hCRTH2, has been expressed in HEK293(EBNA) and characterized with respect to radioligand binding and signal transduction properties. High and low affinity binding sites for PGD(2) were identified in the CRTH2 receptor population by saturation analysis with respective equilibrium dissociation constants (K(D)) of 2.5 and 109 nM. This revealed that the affinity of PGD(2) for CRTH2 is eight times less than its affinity for the DP receptor. 2. Equilibrium competition binding assays revealed that of the compounds tested, only PGD(2) and several related metabolites bound with high affinity to CRTH2 (K(i) values ranging from 2.4 to 34.0 nM) with the following rank order of potency: PGD(2)>13,14-dihydro-15-keto PGD(2)>15-deoxy-Delta(12,14)-PGJ(2)>PGJ(2)>Delta(12)-PGJ(2)>15(S)-15 methyl-PGD(2). This is in sharp contrast with the rank order of potency obtained at DP : PGD(2)>PGJ(2)>Delta(12)-PGJ(2)>15-deoxy-Delta(12,14)-PGJ(2) >>>13,14-dihydro-15-keto-PGD(2). 3. Functional studies demonstrated that PGD(2) activation of recombinant CRTH2 results in decrease of intracellular cAMP in a pertussis toxin-sensitive manner. Therefore, we showed that CRTH2 can functionally couple to the G-protein G(alphai/o). PGD(2) and related metabolites were tested and their rank order of potency followed the results of the membrane binding assay. 4. By Northern blot analysis, we showed that, besides haemopoietic cells, CRTH2 is expressed in many other tissues such as brain, heart, thymus, spleen and various tissues of the digestive system. In addition, in situ hybridization studies revealed that CRTH2 mRNA is expressed in human eosinophils. Finally, radioligand binding studies demonstrated that two eosinophilic cell lines, butyric acid-differentiated HL-60 and AML 14.3D10, also endogenously express CRTH2.
| S-EPMC1573602 | biostudies-literature
Project description:Th2 cells must sense and adapt to the tissue milieu in order to provide protective host immunity and tissue repair. Here, we examined the mechanisms promoting Th2 cell differentiation and function within the small intestinal lamina propria. Single cell RNA-seq analyses of CD4+ T cells from the small intestinal lamina propria of helminth infected mice revealed high expression of the gene Epas1, encoding the transcription factor hypoxia-inducible factor 2a (HIF2α). In vitro, exposure to hypoxia or genetic HIF2α activation promoted Th2 cell differentiation, even under non-polarizing conditions. In mice, HIF2α activation in CD4+ T cells promoted intestinal Th2 cell accumulation in the absence of infection, and HIF2α-deficiency impaired CD4+ T cell-mediated host immunity to intestinal helminth infection. Our findings identified hypoxia, and the oxygen-regulated transcription factor Hypoxia-Inducible Factor 2α (HIF2α), as key regulators of Th2 cell differentiation and function within the small intestine.
2025-04-01 | GSE288269 | GEO
Project description:Intestinal dendritic cells (DC) orchestrate the adaptive immune response that balances protection against pathogens and tolerance towards harmless antigens. Yet, it remains largely unknown what molecular mechanisms underly this functional duality. Heligmosomoides polygyrus bakeri (Hpb) is a naturally occurring parasite in mice characterised by unique immune-evasion strategies that counter host protective immunity. Here, we utilised this unique infection environment to study mechanisms by which DC maintain the immune balance. In-depth characterisation of intestinal DC during Hpb infection revealed the emergence of distinct populations of DC that drive protective Th2 responses, versus others with immunoregulatory properties. We also identified that the skewing of intestinal DC towards immunoregulatory functions was due to TGFb signalling via endogenous sources or by Hpb-produced TGFb-mimic molecules. Thus, our results present a mechanistic explanation for Hpb’s ability to modulate the adaptive immune system. Furthermore, these data offer an example of how heterogeneity within the DC compartment can determine the simultaneous generation of both pro- and anti-inflammatory immune responses.
2025-03-17 | GSE291087 | GEO
Project description:Prostaglandin D2 (PGD2) signals through the G protein-coupled receptor (GPCR) CRTH2 to mediate various inflammatory responses. CRTH2 is the only member of the prostanoid receptor family that is phylogenetically distant from others, implying a nonconserved mechanism of lipid action on CRTH2. Here, we report a crystal structure of human CRTH2 bound to a PGD2 derivative, 15R-methyl-PGD2 (15mPGD2), by serial femtosecond crystallography. The structure revealed a "polar group in"-binding mode of 15mPGD2 contrasting the "polar group out"-binding mode of PGE2 in its receptor EP3. Structural comparison analysis suggested that these two lipid-binding modes, associated with distinct charge distributions of ligand-binding pockets, may apply to other lipid GPCRs. Molecular dynamics simulations together with mutagenesis studies also identified charged residues at the ligand entry port that function to capture lipid ligands of CRTH2 from the lipid bilayer. Together, our studies suggest critical roles of charge environment in lipid recognition by GPCRs.
| S-EPMC8364189 | biostudies-literature
Project description:Death of intestinal epithelial cells (IECs) is important in the pathological process of intestinal inflammatory diseases. TNF acts as one pathogenic driver for inducing IEC death and substantial intestinal inflammation. However, the physiological protective mechanisms for suppressing TNF-induced IEC death remain poorly understood. Here, we report that EF-hand domain-containing protein D2 (EFHD2), highly expressed in normal intestine tissues but decreased in intestinal biopsy samples of ulcerative colitis patients, protects the intestinal epithelium from TNF-induced IEC apoptosis. EFHD2 inhibits TNF-induced apoptosis in primary IECs and intestinal organoids (enteroids). Mice deficient of Efhd2 in IECs exhibit excessive IEC death and exacerbated experimental colitis. Mechanistically, EFHD2 interacts with Cofilin to suppress the phosphorylation of Cofilin, leading to the inhibition of TNF receptor Ⅰ (TNFR1) internalization and TNF-induced apoptosis. Our findings define EFHD2 as an endogenous suppressor of IEC death to protect intestine inflammation, providing new insight to the regulation of death receptor signaling and control of intestinal inflammatory diseases.
2024-01-14 | PXD048587 |
Project description:Prostaglandins (PGs) are key inflammatory mediators involved in wound healing and regulating hair growth; however, their role in skin regeneration after injury is unknown. Using wound-induced hair follicle neogenesis (WIHN) as a marker of skin regeneration, we hypothesized that PGD2 decreases follicle neogenesis. PGE2 and PGD2 were elevated early and late, respectively, during wound healing. The levels of WIHN, lipocalin-type prostaglandin D2 synthase (Ptgds), and its product PGD2 each varied significantly among background strains of mice after wounding, and all correlated such that the highest Ptgds and PGD2 levels were associated with the lowest amount of regeneration. In addition, an alternatively spliced transcript variant of Ptgds missing exon 3 correlated with high regeneration in mice. Exogenous application of PGD2 decreased WIHN in wild-type mice, and PGD2 receptor Gpr44-null mice showed increased WIHN compared with strain-matched control mice. Furthermore, Gpr44-null mice were resistant to PGD2-induced inhibition of follicle neogenesis. In all, these findings demonstrate that PGD2 inhibits hair follicle regeneration through the Gpr44 receptor and imply that inhibition of PGD2 production or Gpr44 signaling will promote skin regeneration.
| S-EPMC3593761 | biostudies-literature