Skeletal muscle must perform a wide range of kinds of work, and different fiber types have evolved to accommodate these different tasks. The attributes of fibers are determined in large part by the coordinated regulation of oxidative capacity, as reflected by mitochondrial content, and the specific makeup of myofibrillar proteins. Adult muscle fibers contain four myosin heavy chain isotypes: I, IIa, IIx and IIb. Type I and IIa fibers have slower twitches and are rich in mitochondria, while type IIb fibers are fast-twitch and predominantly glycolytic. The intermediate IIx fibers are less well understood. Previous work had shown that the transcriptional coactivator PGC-1 alpha could drive the formation of type I and IIa muscle fibers. We show here that mice with transgenic expression of PGC-1 beta in skeletal muscle results in marked induction of IIx fibers. The fibers in transgenic mice are rich in mitochondria and are highly oxidative. As a result, PGC-1 beta transgenic animals can perform oxidative activity for longer and at higher work loads than wild type animals. In cell culture, PGC-1 beta coactivates the MEF2 family of transcription factors to stimulate the MHC IIx promoter. Together, these data indicate that PGC-1 beta is sufficient to drive the formation in vivo of highly oxidative fibers with type IIx characteristics.
The transcriptional coactivator PGC-1beta drives the formation of oxidative type IIX fibers in skeletal muscle.
Sex, Specimen part
View SamplesIn contrast to the well-established role of oxidative muscle fibers in regulating fatty acid oxidation and whole body metabolism, little is known that about the function of fast/glycolytic muscle fibers in these processes. Here, we generated a skeletal muscle-specific, conditional transgenic mouse expressing a constitutively-active form of Akt1. Transgene activation led to muscle hypertrophy due to the growth of type IIb muscle fibers, which was accompanied by an increase in strength. These mice were then used to assess the consequence of building fast/glycolytic muscle fibers on adiposity and metabolism. Akt1 transgene induction in obese mice resulted in reductions in body weight and fat mass, a resolution of hepatic steatosis and improved metabolic parameters. These effects were achieved independent of changes in physical activity and levels of food consumption. Akt1-mediated skeletal muscle growth opposed the effects of high fat/sucrose diet on transcript expression patterns in the liver, and increased hepatic fatty acid oxidation and ketone body production. Our findings indicate that an increase in fast/glycolytic muscle mass can result in the regression of obesity and obesity-related metabolic disorders in part through its ability to alter fatty acid metabolism in remote tissues.
Fast/Glycolytic muscle fiber growth reduces fat mass and improves metabolic parameters in obese mice.
Sex, Specimen part, Treatment
View SamplesIPF (n=20) and control (n=19) samples were obtained through the LTRC and were sequenced on an Illumina HiSeq 2000 following TruSeq RNA Sample Prep Kit v2 library preparation. Overall design: Cross-sectional samples were analyzed. IPF diagnosis was based on American Thoracic Society and European Respiratory Society criteria, and all IPF samples displayed typical patterns of usual interstitial pneumonia. RNA libraries were prepared from 200 ng of high quality total RNA according to the manufacturer’s instructions for the TruSeq RNA Sample Prep Kit v2 (Illumina, San Diego, CA). The concentration and size distribution of TruSeq libraries was determined on an Agilent Bioanalyzer DNA 1000 chip (Santa Clara, CA), and a final quantification, using Qubit fluorometry (Invitrogen, Carlsbad, CA), was conducted to confirm sample concentration. Libraries were loaded onto paired end flow cells at concentrations of 8-10 pM to generate cluster densities of 700,000/mm2 following Illumina’s standard protocol using the Illumina cBot and cBot Paired end cluster kit version 3. The flow cells were sequenced as 51 X 2 paired end reads on an Illumina HiSeq 2000 using TruSeq SBS sequencing kit version 3 and SCS version 1.4.8 data collection software. Base-calling was performed using Illumina’s RTA version 1.12.4.2.
Cellular senescence mediates fibrotic pulmonary disease.
Specimen part, Disease, Disease stage, Subject
View SamplesThe healthspan of mice is enhanced by selectively killing senescent cells using a transgenic suicide gene. Achieving the same using small molecules would have a tremendous impact on quality of life and burden of age-related chronic diseases.
The Achilles' heel of senescent cells: from transcriptome to senolytic drugs.
Specimen part, Subject
View SamplesAgeing is the biggest risk factor to cardiovascular health and is associated with increased incidence of cardiovascular disease. Cellular senescence, a process driven in part by telomere shortening has been implicated in age-related cardiac dysfunction. However, the role of cellular senescence and its underlying mechanisms in slowly dividing/post-mitotic cardiomyocytes is not understood. Overall design: We quantify transcription via high throughput RNA sequencing in young (3 months) and old (20 months) mouse cardiomyocytes.
Length-independent telomere damage drives post-mitotic cardiomyocyte senescence.
Age, Cell line, Subject
View SamplesComparison of gene expression profile of HEK293 cells stably expressing a shRNA control (SilX-CT) or a shRNA against BAHD1 (SilX-BAHD1)
Overexpression of the Heterochromatinization Factor BAHD1 in HEK293 Cells Differentially Reshapes the DNA Methylome on Autosomes and X Chromosome.
Cell line
View SamplesComparison of gene expression profile of HEK293-CT cells and HEK293 cells stably over-expressing the BAHD1 gene (HEK-BAHD1)
Overexpression of the Heterochromatinization Factor BAHD1 in HEK293 Cells Differentially Reshapes the DNA Methylome on Autosomes and X Chromosome.
Cell line, Treatment
View SamplesLife-threatening pulmonary influenza can be caused by inborn errors of type I and III IFN immunity. We report a 5 year-old child with severe pulmonary influenza at 2 years. She is homozygous for a loss-of-function IRF9 allele. Her cells activate gamma-activated factor (GAF) STAT1 homodimers but not interferon-stimulated gene factor 3 (ISGF3) trimers (STAT1/STAT2/IRF9) in response to IFN-a2b. The transcriptome induced by IFN-a2b in the patient's cells is much narrower than that of control cells; however, induction of a subset of interferon-stimulated gene transcripts remains detectable. In vitro, the patient's cells do not control three respiratory viruses, influenza A virus (IAV), parainfluenza virus, and respiratory syncytial virus. These phenotypes are rescued by wild-type IRF9, whereas silencing IRF9 expression in control cells increases viral replication. However, the child has controlled various common viruses in vivo, including respiratory viruses other than IAV. Our findings show that human IRF9- and ISGF3-dependent type I and III IFN responsive pathways are essential for controlling IAV. Overall design: Total of 72 samples, 38 samples from primary fibroblasts and 34 samples from EBV-transformed B cells, were analyzed using paired-end RNA sequence data. Out of 38 samples from primary fibroblasts, 3 control samples are paired with no stimulation vs IFNa2b stimulation. Out of 34 samples from B-cells, 3 control samples are paired with no stimuliion vs IFNa2b stimulation. In addition to healthy control subjects, patients with AR complete STAT1 (STAT1 -/-) or STAT2 (STAT2 -/-) deficiency were analyzed for comparison.
Life-threatening influenza pneumonitis in a child with inherited IRF9 deficiency.
Specimen part, Subject
View SamplesNeuronal migration disorders such as lissencephaly and subcortical band heterotopia (SBH) are associated with epilepsy and intellectual disability. Doublecortin (DCX), LIS1 and alpha1-tubulin (TUBA1A), are mutated in these disorders, however corresponding mouse mutants do not show heterotopic neurons in the neocortex. On the other hand, the spontaneously arisen HeCo mouse mutant displays this phenotype. The study of this model reveals novel mechanisms of heterotopia formation. While, HeCo neurons migrate at the same speed as WT, abnormally distributed dividing progenitors were found throughout the cortical wall from E13. Through genetic studies we identified Eml1 as the mutant gene in HeCo mice. No full length transcripts of Eml1 were identified due to a retrotransposon insertion in an intron. Re-expression of Eml1, coding for a microtubule-associated protein, rescues the HeCo progenitor phenotype. We further show that EML1 is mutated in giant ribbon-like heterotopia in human. Our data link abnormal spindle orientations, ectopic progenitors and severe heterotopia in mouse and human.
Mutations in Eml1 lead to ectopic progenitors and neuronal heterotopia in mouse and human.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Role of the BAHD1 Chromatin-Repressive Complex in Placental Development and Regulation of Steroid Metabolism.
Specimen part, Disease, Cell line, Treatment
View Samples