Following skeletal muscle injury, muscle stem cells (satellite cells) are activated, proliferate, and differentiate to form myofibers. We show that mRNA decay protein AUF1 regulates satellite cell function through targeted degradation of specific mRNAs. AUF1 targets certain mRNAs containing 3 AU-rich elements (AREs) for rapid decay. Auf1-/- (KO) mice undergo accelerated skeletal muscle wasting with age and impaired muscle repair following injury. Satellite cell mRNA analysis and regeneration studies demonstrate that auf1-/- satellite cell self-renewal is impaired due to increased stability and overexpression of ARE-mRNAs. Control of ARE-mRNA decay by AUF1 and potentially other ARE-binding proteins represents a mechanism for adult stem cell regulation and is implicated in human muscle wasting diseases. We report the RNA transcript expression profiles from sorted satellite cells isolated from wild type (WT) and AUF1-null (KO) mice hindlimb muscles Overall design: Examination of RNA transcript expression from satellite cells of two genotypes Please note that mice are bred through a C57BL/6 strain of 129 background.
Targeted mRNA Decay by RNA Binding Protein AUF1 Regulates Adult Muscle Stem Cell Fate, Promoting Skeletal Muscle Integrity.
Age, Specimen part, Subject
View SamplesWith this study we wanted to evaluate the impact of murine norovirus infection of germfree mice and to compare it to germfree mice which have received fecal transplants of conventional mice. Overall design: whole small intestinal tissue analysis of 3 germfree, 3 germfree mice infected with murine norovirus and 3 conventionalized germfree mice
An enteric virus can replace the beneficial function of commensal bacteria.
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View SamplesNod2 has been extensively characterized as a bacterial sensor that induces an antimicrobial and inflammatory gene expression program. Therefore, it is unclear why Nod2 mutations that disrupt bacterial recognition are paradoxically among the highest risk factors for Crohns disease, which involves an exaggerated immune response directed at intestinal bacteria. Previous studies from our lab have shown that mice deficient in Atg16L1, another Crohns disease susceptibility gene, develop abnormalities in Paneth cells, specialized epithelial cells in the small intestine involved in antimicrobial responses.
Bacterial sensor Nod2 prevents inflammation of the small intestine by restricting the expansion of the commensal Bacteroides vulgatus.
Age, Specimen part
View SamplesTranscriptional profile of monocytes in the colon in response to C. rodentium infection Overall design: Eight samples have been analyzed. All are from Cd11b+Ly6C+ inflammatory monocytes sorted from colonic tissue 9 days after C. rodentium infection from Atg16L1HM(4) and WT(4) mice.
Autophagy proteins suppress protective type I interferon signalling in response to the murine gut microbiota.
Age, Specimen part, Subject
View SamplesWe previously found that mice deficient in the CD susceptibility gene Nod2 develop small intestinal abnormalities including impaired mucus production by goblet cells and susceptibility to injury, which were associated with interferon-gamma producing intraepithelial lymphocytes. These abnormalities were caused by a striking expansion of a common member of the microbiota, Bacteroides vulgatus. Remarkably, infection of Nod2-deficient mice with the helminth Trichuris muris led to a TH2 response that eliminated B. vulgatus colonization and intestinal abnormalities. In addition, treatment with recombinant IL13 (rIL13) or recombinant IL4 reduced B. vulgatus levels and eliminated goblet cell defects, suggesting that type 2 cytokines alone can reverse intestinal abnormalities in the absence of helminth infection. To determine the mechanism by which type 2 cytokines protected Nod2-/- mice from intestinal abnormalities, we performed RNA-seq on small intestinal tissue from WT, Nod2-/- and rIL13 treated Nod2-/- mice. We found that rIL13 treatment induced a wound healing response characterized by M2 macrophage activation genes. Hence, type 2 cytokines can reverse inflammatory imbalances in the composition of the gut microbiota that occurs in a genetically susceptible host. Overall design: Comparison of small intestinal transcriptome in WT, Nod2-/-, and rIL-13 treated Nod2-/- mice.
Helminth infection promotes colonization resistance via type 2 immunity.
Specimen part, Subject
View SamplesThe identification of Atg16L1 as a susceptibility gene has implicated antibacterial autophagy in the pathogenesis of Crohn''s disease, a major type of inflammatory bowel disease (IBD). However, the role of Atg16L1 during extracellular bacterial infections of the intestine has not been sufficiently examined and compared to the function of other IBD susceptibility genes such as Nod2. We now find that Atg16L1 mutant mice are extraordinarily resistant to intestinal disease induced by the model bacterial pathogen Citrobacter rodentium. We further demonstrate that Atg16L1 deficiency alters the intestinal environment to mediate an enhanced immune response that is dependent on monocytic cells, and that Atg16L1/Nod2 double mutant mice lose this advantage. These results reveal an unappreciated immuno-suppressive function of an IBD gene, and raise the possibility that gene variants that affect the autophagy pathway were evolutionarily maintained to protect against certain life-threatening infections. Overall design: Twenty samples have been analyzed. All are colonic tissue from mice. Controls are uninfected WT mice, uninfected Atg16L1 mutant mice (Atg16L1HM) (n=3/genotype). Treatment conditions are tissue from WT and Atg16L1 mutant mice 6 days after C. rodentium infection (n=4/genotype) and 15 days after infection (n=3/genotype).
A deficiency in the autophagy gene Atg16L1 enhances resistance to enteric bacterial infection.
Specimen part, Subject
View SamplesThe aim of this study is to survey global gene expression of total thymocytes from wild-type mice and Atg16l1 mutant (hypomorph) mice.
A key role for autophagy and the autophagy gene Atg16l1 in mouse and human intestinal Paneth cells.
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View SamplesSusceptibility to Crohn's disease, a complex inflammatory disease involving the small intestine, is controlled by over 30 loci. One Crohn's disease risk allele is in ATG16L1, a gene homologous to the essential yeast autophagy gene ATG16 (ref. 2). It is not known how ATG16L1 or autophagy contributes to intestinal biology or Crohn's disease pathogenesis. To address these questions, we generated and characterized mice that are hypomorphic for ATG16L1 protein expression, and validated conclusions on the basis of studies in these mice by analysing intestinal tissues that we collected from Crohn's disease patients carrying the Crohn's disease risk allele of ATG16L1. Here we show that ATG16L1 is a bona fide autophagy protein. Within the ileal epithelium, both ATG16L1 and a second essential autophagy protein ATG5 are selectively important for the biology of the Paneth cell, a specialized epithelial cell that functions in part by secretion of granule contents containing antimicrobial peptides and other proteins that alter the intestinal environment. ATG16L1- and ATG5-deficient Paneth cells exhibited notable abnormalities in the granule exocytosis pathway. In addition, transcriptional analysis revealed an unexpected gain of function specific to ATG16L1-deficient Paneth cells including increased expression of genes involved in peroxisome proliferator-activated receptor (PPAR) signalling and lipid metabolism, of acute phase reactants and of two adipocytokines, leptin and adiponectin, known to directly influence intestinal injury responses. Importantly, Crohn's disease patients homozygous for the ATG16L1 Crohn's disease risk allele displayed Paneth cell granule abnormalities similar to those observed in autophagy-protein-deficient mice and expressed increased levels of leptin protein. Thus, ATG16L1, and probably the process of autophagy, have a role within the intestinal epithelium of mice and Crohn's disease patients by selective effects on the cell biology and specialized regulatory properties of Paneth cells.
A key role for autophagy and the autophagy gene Atg16l1 in mouse and human intestinal Paneth cells.
No sample metadata fields
View SamplesThe early life microbiome plays important roles in host immunological and metabolic development. Because type 1 diabetes (T1D) incidence has been increasing substantially in recent decades, we hypothesized that early-life antibiotic use alters gut microbiota that predisposes to disease. Using NOD mice that are genetically susceptible to T1D, we examined the effects of exposure to either continuous low-dose antibiotics or pulsed therapeutic antibiotics (PAT) early in life, mimicking childhood exposures. We found that in mice receiving PAT, T1D incidence was significantly higher, microbial community composition and structure differed compared with controls. In pre-diabetic male PAT mice, the intestinal lamina propria had lower Th17 and T reg proportions and intestinal SAA expression than in controls, suggesting key roles in transducing the altered microbiota signals. PAT affected microbial lipid metabolism and host cholesterol biosynthetic gene expression. These findings show that early-life antibiotic treatments alter the gut microbiota and its metabolic capacities, intestinal gene expression, and T-cell populations, accelerating T1D onset in NOD mice.
Antibiotic-mediated gut microbiome perturbation accelerates development of type 1 diabetes in mice.
Sex, Specimen part, Disease, Disease stage, Treatment
View SamplesThe goal of our study is to determine whether Atg16L1 deficiency leads to differences in the transcriptional profile of CD11c+ Dendritic Cells, ultimately leading to an increased inflammatory phenotype.
Autophagy gene Atg16L1 prevents lethal T cell alloreactivity mediated by dendritic cells.
Specimen part
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