Calorie restriction (CR) is a dietary intervention that extends lifespan and healthspan in a variety of organisms. CR improves mitochondrial energy production, fuel oxidation and reactive oxygen species scavenging in skeletal muscle and other tissues, and these processes are thought to be critical to the benefits of CR. PGC-1a is a transcriptional coactivator that regulates mitochondrial function and is induced by CR. Consequently, many of the mitochondrial and metabolic benefits of CR are attributed to increased PGC-1a activity. To test this model for the first time, we examined the metabolic and mitochondrial response to CR in mice lacking skeletal muscle PGC-1a (MKO). Surprisingly, MKO mice demonstrated a normal improvement in glucose homeostasis in response to CR, indicating that skeletal muscle PGC-1a is dispensable for the whole-body benefits of CR. In contrast, gene expression profiling and electron microscopy demonstrated that PGC-1a is required for the full CR-induced increases in mitochondrial gene expression and mitochondrial density in skeletal muscle. These results demonstrate that PGC-1a is a major regulator of the mitochondrial response to CR in skeletal muscle, but surprisingly show that neither PGC-1a nor mitochondrial biogenesis in skeletal muscle are required for the metabolic benefits of CR.
Skeletal muscle transcriptional coactivator PGC-1α mediates mitochondrial, but not metabolic, changes during calorie restriction.
Specimen part
View SamplesMEN1 is a tumor suppressor gene loss of which causes lipoma (fatty tumors under the skin) and many other endocrine and non-endocrine tumors. It's target genes in fat cells (adipocytes) are unknown. Gene expression in adipocytes that were in vitro differentiated from mouse embryonic stem cells (mESCs) of Men1-nul l(Men1-KO) and WT mice were compared to assess the expression of genes upon menin loss in adipocytes that could lead to the deveopment of lipoma.
Consequence of Menin Deficiency in Mouse Adipocytes Derived by In Vitro Differentiation.
Specimen part
View SamplesWe analysed the G-actin regulated transcriptome by gene expression analysis using previously characterised actin binding drugs. We found many known MAL/MRTF-dependent target genes of serum response factor (SRF) as well as unknown directly regulated genes.
Negative regulation of the EGFR-MAPK cascade by actin-MAL-mediated Mig6/Errfi-1 induction.
Time
View SamplesOur laboratory wanted to define the transcription profile of aged skeletal muscle. For this reason, we performed a triplicate microarray study on young (3 weeks) and aged (24 months) gatrocnemius muscle from wild-type C57B16 Mice
Transcriptional profiling of skeletal muscle reveals factors that are necessary to maintain satellite cell integrity during ageing.
Sex
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Type I and type III interferons drive redundant amplification loops to induce a transcriptional signature in influenza-infected airway epithelia.
Specimen part
View SamplesWe used microarrays to detail the global programme of gene expression in response to Influenza A (PR8) infection
Type I and type III interferons drive redundant amplification loops to induce a transcriptional signature in influenza-infected airway epithelia.
Specimen part
View SamplesMast cells, activated by antigen via the high affinity receptor for IgE (FcRI), release an array of pro-inflammatory mediators that contribute to allergic disorders such as asthma and anaphylaxis. The KIT ligand, stem cell factor (SCF), is critical for mast cell expansion, differentiation and survival, and, under acute conditions, enhances mast cell activation. However, extended SCF exposure in vivo conversely protects against fatal antigen-mediated anaphylaxis. In investigating this dichotomy, we identified a novel mode of regulation of the mast cell activation phenotype through SCF-mediated programming. We found that mouse bone marrow-derived mast cells chronically exposed to SCF displayed a marked attenuation of FcRI-mediated degranulation and cytokine production. The hypo-responsive phenotype was not a consequence of altered signals regulating calcium flux or protein kinase C, but of ineffective cytoskeletal reorganization, with evidence implicating a down-regulation of expression of the Src kinase Hck. Collectively, these findings demonstrate a major role for SCF in the homeostatic control of mast cell activation with potential relevance to mast cell-driven disease and the development of novel approaches for the treatment of allergic disorders.
Stem cell factor programs the mast cell activation phenotype.
Specimen part, Treatment
View SamplesInterleukin-33 (IL-33) is elevated in afflicted tissues of patients with mast cell-dependent chronic allergic diseases. Based on its acute effects on mouse mast cells (MCs), IL-33 is thought to play a role in the pathogenesis of allergic disease through MC activation. However, the manifestations of chronic IL-33 exposure on human MC function, which best reflect the conditions associated with chronic allergic disease, are unknown. We now find that long-term exposure of human and mouse MCs to IL-33 results in a substantial reduction of MC activation in response to antigen. This reduction required >72 h exposure to IL-33 for onset and 1-2 wk for reversion following IL-33 removal. This hypo-responsive phenotype was determined to be a consequence of MyD88-dependent attenuation of signaling processes necessary for MC activation including antigen-mediated calcium mobilization and cytoskeletal reorganization; potentially as a consequence of down-regulation of the expression of PLCg1 and Hck. These findings suggest that IL-33 may play a protective, rather than a causative role in MC activation under chronic conditions and, furthermore, reveal regulated plasticity in the MC activation phenotype. The ability to down-regulate MC activation in this manner may provide alternative approaches for treatment of MC-driven disease.
IL-33 induces a hyporesponsive phenotype in human and mouse mast cells.
Specimen part, Treatment
View SamplesThe HSA21-mES Cell Bank includes, in triplicate clones, thirty-two murine orthologs of HSA21 genes, which can be overexpressed in an inducible manner using the Tet-off system integrated in the Rosa26 locus.
A mouse embryonic stem cell bank for inducible overexpression of human chromosome 21 genes.
Specimen part
View SamplesAlthough it has recently been shown that A/J mice are highly susceptible to Staphylococcus aureus sepsis as compared to C57BL/6J, the specific genes responsible for this differential phenotype are unknown. Using chromosome substitution strains (CSS), we found that factors on chromosomes (chr) 8, 11, and 18 are responsible for susceptibility to S. aureus sepsis in A/J mice. F1 mice from C57BL/6J X CSS8 cross (C8A) and C57BL/6J X CSS18 (C18A) were also susceptible to S. aureus (median survival < 48 h), whereas F1 mice from C57BL/6J X CSS11 cross (C11A) were resistant (median survival > 120 h) to S. aureus. Bacterial loads in the kidney were consistent with F1 median survivals, with higher bacterial counts in susceptible mice. No sexlinked associations with susceptibility were noted in F1 intercrosses. Using whole genome transcription profiling, we identified a total of 192 genes on chromosomes 8, 11, and 18 which are differentially expressed between A/J and C57BL/6J in the setting of S. aureus infection. Of these, 28 genes had Gene Ontology annotations indicating a potential immune response function. These 28 genes are associated with susceptibility to S. aureus in A/J mice, and are potential determinants of susceptibility to S. aureus infection in humans.
Two genes on A/J chromosome 18 are associated with susceptibility to Staphylococcus aureus infection by combined microarray and QTL analyses.
Time
View Samples