TGF-beta-independent function of SMAD4 preconditions naïve CD8 T-cells to prevent severe microbiota-driven chronic intestinal inflammation.
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE188934 | GEO | 2022/03/15
REPOSITORIES: GEO
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Project description:SMAD4, a key mediator of TGF-beta signaling, plays a crucial role in T cells to prevent chronic intestinal inflammation through unknown mechanisms. We reveal that SMAD4 in CD8 T cells prevents chronic intestinal inflammation primarily in a TGF-beta-independent manner. Mechanistically, SMAD4, in CD8 T cells, acts as a basal and tonic repressor of TGF-beta-target genes at the transcriptional and epigenetic level, prior to any TGF-beta signal. SMAD4 deletion affects aberrantly a wide range of TGF-beta-target genes, thereby promoting accumulation and epithelial retention of CD8.alpha.beta T cells inversely to total TGF-beta signaling disruption. Moreover, SMAD4 deletion unleashes the expression of TGF-beta-signaling-repressors and hampers TGF-β-mediated CD8 T cell immunosuppression, eliciting their chronic activation. Hence, in a feedforward mechanism, SMAD4 both blocks the TGF-beta signature in CD8 T cells and pre-sensitizes them to TGF-beta.
2022-03-15 | GSE188933 | GEO
Project description:SMAD4, a key mediator of TGF-beta signaling, plays a crucial role in T cells to prevent chronic intestinal inflammation through unknown mechanisms. We reveal that SMAD4 in CD8 T cells prevents chronic intestinal inflammation primarily in a TGF-beta-independent manner. Mechanistically, SMAD4, in CD8 T cells, acts as a basal and tonic repressor of TGF-beta-target genes at the transcriptional and epigenetic level, prior to any TGF-beta signal. SMAD4 deletion affects aberrantly a wide range of TGF-beta-target genes, thereby promoting accumulation and epithelial retention of CD8.alpha.beta T cells inversely to total TGF-beta signaling disruption. Moreover, SMAD4 deletion unleashes the expression of TGF-beta-signaling-repressors and hampers TGF-β-mediated CD8 T cell immunosuppression, eliciting their chronic activation. Hence, in a feedforward mechanism, SMAD4 both blocks the TGF-beta signature in CD8 T cells and pre-sensitizes them to TGF-beta.
2022-03-15 | GSE188932 | GEO
Project description:SMAD4, a mediator of TGF-β signaling, plays an important role in T cells to prevent inflammatory bowel disease (IBD). However, the precise mechanisms underlying this control remain elusive. Using both genetic and epigenetic approaches, we revealed an unexpected mechanism by which SMAD4 prevents naive CD8+ T cells from becoming pathogenic for the gut. Prior to the engagement of the TGF-β receptor, SMAD4 restrains the epigenetic, transcriptional, and functional landscape of the TGF-β signature in naive CD8+ T cells. Mechanistically, prior to TGF-β signaling, SMAD4 binds to promoters and enhancers of several TGF-β target genes, and by regulating histone deacetylation, suppresses their expression. Consequently, regardless of a TGF-β signal, SMAD4 limits the expression of TGF-β negative feedback loop genes, such as Smad7 and Ski, and likely conditions CD8+ T cells for the immunoregulatory effects of TGF-β. In addition, SMAD4 ablation conferred naive CD8+ T cells with both a superior survival capacity, by enhancing their response to IL-7, as well as an enhanced capacity to be retained within the intestinal epithelium, by promoting the expression of Itgae, which encodes the integrin CD103. Accumulation, epithelial retention, and escape from TGF-β control elicited chronic microbiota-driven CD8+ T cell activation in the gut. Hence, in a TGF-β-independent manner, SMAD4 imprints a program that preconditions naive CD8+ T cell fate, preventing IBD.
| S-EPMC9012287 | biostudies-literature
Project description:TGF-beta-independent function of SMAD4 preconditions naïve CD8 T-cells to prevent severe microbiota-driven chronic intestinal inflammation.
| PRJNA780795 | ENA
Project description:TGF-beta-independent function of SMAD4 preconditions naïve CD8 T-cells to prevent severe microbiota-driven chronic intestinal inflammation [ChIPseq]
| PRJNA780804 | ENA
Project description:TGF-beta-independent function of SMAD4 preconditions naïve CD8 T-cells to prevent severe microbiota-driven chronic intestinal inflammation [RNAseq]
| PRJNA780803 | ENA
Project description:SMAD4 is the only common SMAD in TGF-? signaling that usually impedes immune cell activation in the tumor microenvironment. However, we demonstrated here that selective deletion of Smad4 in NK cells actually led to dramatically reduced tumor cell rejection and augmented tumor cell metastases, reduced murine CMV clearance, as well as impeded NK cell homeostasis and maturation. This was associated with a downregulation of granzyme B (Gzmb), Kit, and Prdm1 in Smad4-deficient NK cells. We further unveiled the mechanism by which SMAD4 promotes Gzmb expression. Gzmb was identified as a direct target of a transcriptional complex formed by SMAD4 and JUNB. A JUNB binding site distinct from that for SMAD4 in the proximal Gzmb promoter was required for transcriptional activation by the SMAD4-JUNB complex. In a Tgfbr2 and Smad4 NK cell-specific double-conditional KO model, SMAD4-mediated events were found to be independent of canonical TGF-? signaling. Our study identifies and mechanistically characterizes unusual functions and pathways for SMAD4 in governing innate immune responses to cancer and viral infection, as well as NK cell development.
| S-EPMC6205382 | biostudies-literature
Project description:Arginase 1 (Arg1), which converts L-arginine into ornithine and urea, exerts pleiotropic immunoregulatory effects. Patients with inflammatory bowel disease (IBD) show an enhanced expression and activity of Arg1 in the intestinal (sub-)mucosa, but the function of Arg1 in IBD remains poorly characterized. Here, we found that Arg1 expression correlates with the degree of inflammation in colitic tissues of IBD patients. In mice with - experimental colitis Arg1 was upregulated in an IL-4-/IL-13- and intestinal microbiota-dependent manner. Tie2-Cre+/-Arg1fl/fl mice lacking Arg1 in hematopoietic and endothelial cells recovered faster from colitis than Arg1-expressing littermates. This correlated with decreased vessel density, compositional changes in the intestinal microbiota, diminished infiltration by myeloid cellsand an accumulation of intraluminal polyamines that are associated with epithelial healing. Dietary L-arginine restriction abolished the protective effect of Arg1-deletion, suggesting that protection is related to an increased availability of L-arginine. Fecal microbiota transfers from Tie2-Cre+/-Arg1fl/fl mice into wildtype recipients restored the protective, anti-inflammatory phenotype while transfers from wildtype littermates into Arg1-deficient mice prevented the accelerated recovery from colitis. Thus, altered intestinal microbiota and metabolic products in Tie2-Cre+/-Arg1fl/fl mice account for the accelerated resolution from colitis in the absence of Arg1. Subsequently, L-arginine serves as novel therapeutic and diagnostic target for clinical intervention in IBD patients.
2020-06-07 | GSE151931 | GEO
Project description:Background & aimsMice lacking the receptor Toll-like receptor 5 (TLR5-null mice), which recognizes flagellin, have an altered intestinal microbiota composition compared with wild-type mice; they develop low-grade inflammation and metabolic syndrome and are prone to colitis. The relative roles of intestinal epithelial cell (IEC) vs dendritic cell (DC) TLR5 in mediating these phenotypes are not clear; modification of intestinal microbiota composition has been reported to reflect animal husbandry practices rather than loss of TLR5. We generated mice with specific disruption of Tlr5 in IECs or DCs by using a breeding scheme that allows comparison with cohoused siblings as controls.MethodsWe generated C57BL/6 mice with LoxP sites flanking Tlr5. These mice were crossed with mice expressing Cre recombinase, regulated by the villin or CD11c promoters, to generate mice that lacked expression of TLR5 by IECs (TLR5(ΔIEC)) or DCs (TLR5(ΔDC)), respectively. Tlr5(fl/fl) siblings were used as controls. On weaning, mice were housed by sex and genotype or by sex only (genotypes cohoused). Mice were examined for basal phenotypes, including microbiota composition; we also analyzed responses to pathobiont challenge, administration of dextran sodium sulfate, and high-fat diets.ResultsSimilar to previous findings from TLR5-null mice, TLR5(ΔIEC) mice had low-grade inflammation (mild splenomegaly, shortened colons, and increased fecal levels of lipocalin 2), metabolic syndrome, and an inability to clear pathobionts and were prone to developing colitis compared with their sibling controls under both housing conditions. Development of this inflammation in the TLR5(ΔIEC) mice was eliminated by administration of antibiotics and associated with alterations in localization of microbiota and levels of fecal lipopolysaccharide and flagellin. The composition of the microbiota clustered more closely according to genotype than housing. Loss of TLR5 from DCs did not associate with development of inflammation-associated phenotypes or alterations in the composition of the microbiota but resulted in complete loss of flagellin-induced production of interleukin-22.ConclusionsIn mice, flagellin activation of TLR5 on DCs leads to production of interleukin-22. Expression of TLR5 on IECs regulates the composition and localization of the intestinal microbiota, preventing diseases associated with intestinal inflammation.
| S-EPMC4253564 | biostudies-literature
Project description:Pancreatic Ductal Adenocarcinoma (PDA) has a mortality rate that nearly matches its incidence rate. Transforming Growth Factor Beta (TGF-β) is a cytokine with a dual role in tumor development switching from a tumor suppressor to a tumor promoter. There is limited knowledge of how TGF-β function switches during tumorigenesis. Mucin 1 (MUC1) is an aberrantly glycosylated, membrane-bound, glycoprotein that is overexpressed in >80% of PDA cases and is associated with poor prognosis. In PDA, MUC1 promotes tumor progression and metastasis via signaling through its cytoplasmic tail (MUC1-CT) and interacting with other oncogenic signaling molecules. We hypothesize that high levels of MUC1 in PDA may be partly responsible for the TGF-β functional switch during oncogenesis. We report that overexpression of MUC1 in BxPC3 human PDA cells (BxPC3.MUC1) enhances the induction of epithelial to mesenchymal transition leading to increased invasiveness in response to exogenous TGF-β1. Simultaneously, these cells resist TGF-β induced apoptosis by downregulating levels of cleaved caspases. We show that mutating the tyrosines in MUC1-CT to phenylalanine reverses the TGF-β induced invasiveness. This suggests that the tyrosine residues in MUC1-CT are required for TGF-β induced invasion. Some of these tyrosines are phosphorylated by the tyrosine kinase c-Src. Thus, treatment of BxPC3.MUC1 cells with a c-Src inhibitor (PP2) significantly reduces TGF-β induced invasiveness. Similar observations were confirmed in the Chinese hamster ovarian (CHO) cell line. Data strongly suggests that MUC1 may regulate TGF-β function in PDA cells and thus have potential clinical relevance in the use of TGF-β inhibitors in clinical trials.
| S-EPMC5805524 | biostudies-literature