Statins, the 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase inhibitors, are widely prescribed for treatment of hypercholesterolemia. Although statins are generally well tolerated, up to ten percent of patients taking statins experience muscle related adverse events. Myalgia, defined as muscle pain without elevated creatinine phosphokinase (CPK) levels, is the most frequent reason for discontinuation of statin therapy. The mechanisms underlying statin-associated myalgia are not clearly understood. To elucidate changes in gene expression associated with statin-induced myalgia, we compared profiles of gene expression in the biopsied skeletal muscle from statin-intolerant patients undergoing statin re-challenge versus those of statin-tolerant controls. A robust separation of statin-intolerant and statin-tolerant cohorts was revealed by Principal Component Analysis of differentially expressed genes (DEGs). To identify putative gene expression and metabolic pathways that may be perturbed in skeletal muscles of statin intolerant patients, we subjected DEGs to Ingenuity Pathways (IPA) and DAVID (Database for Annotation, Visualization and Integrated Discovery) analyses. The most prominent pathways altered by statins included cellular stress, apoptosis, senescence and DNA repair (TP53, BARD1, Mre11 and RAD51); activation of pro-inflammatory immune response (CXCL12, CST5, POU2F1); protein catabolism, cholesterol biosynthesis, protein prenylation and RAS-GTPase activation (FDFT1, LSS, TP53, UBD, ATF2, H-ras). Based on these data we tentatively conclude that persistent myalgia in response to statins may emanate from cellular stress underpinned by mechanisms of post-inflammatory repair and regeneration. We also posit that this subset of individuals are genetically predisposed to eliciting altered statin metabolism and/or increased end-organ susceptibility that lead to a range of statin-induced myopathies. This mechanistic scenario further bolstered by the discovery that a number of single nucleotide polymorphisms (e.g., SLCO1B1, SLCO2B1 and RYR2) associated with statin myopathy were observed with increased frequency among statin-intolerant study subjects.
Patients experiencing statin-induced myalgia exhibit a unique program of skeletal muscle gene expression following statin re-challenge.
Specimen part
View SamplesPurpose: The goal of this study was to determine the gene expression changes that occur over 7 days in parralyzed muscle in response to isometric contraction elicited by electrical stimulation initiated 4 months after spinal cord injury and to compare such changes to those observed in a normal muscle subjected to overload.
Electrical stimulation modulates Wnt signaling and regulates genes for the motor endplate and calcium binding in muscle of rats with spinal cord transection.
Sex, Specimen part
View SamplesType 2 diabetes differs from type 1 diabetes in its pathogenesis. Type 1 diabetic diaphragm has altered gene expression which includes lipid and carbohydrate metabolism, ubiquitination and oxidoreductase activity. The objectives of the present study were to assess respiratory muscle gene expression changes in type 2 diabetes and to determine whether they are greater for the diaphragm than an upper airway muscle. Diaphragm and sternohyoid muscle from Zucker diabetic fatty (ZDF) rats were analyzed with Affymetrix gene expression arrays. The two muscles had 97 and 102 genes, respectively, with at least 1.5-fold significantly changed expression with diabetes, and these were assigned to gene ontology groups based on over-representation analysis. Several significantly changed groups were common to both muscles, including lipid metabolism, carbohydrate metabolism, muscle contraction, ion transport and collagen, although the number of genes and the specific genes involved differed considerably for the two muscles. In both muscles there was a shift in metabolism gene expression from carbohydrate metabolism toward lipid metabolism, but the shift was greater and involved more genes in diabetic diaphragm than diabetic sternohyoid muscle. Groups present in only diaphragm were blood circulation and oxidoreductase activity. Groups present in only sternohyoid were immune & inflammation and response to stress & wounding, with complement genes being a prominent component. In conclusion, type 2 diabetes-induced gene expression changes in respiratory muscles has both similarities and differences relative to previous data on type 1 diabetes gene expression. Furthermore, the diabetic alterations in gene expression differ between diaphragm and sternohyoid.
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Sex, Age, Specimen part
View SamplesIn order to examine the changes in gene expression between normal and myotonic dystrophic animals, gene expression array studies were done with extensor digitorum longus (EDL) of transgenic HSALR line 20b mice using Affymetrix MOE430 2.0 microarrays.
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Age
View SamplesThis SuperSeries is composed of the SubSeries listed below.
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Age, Specimen part
View SamplesEffect of type 1 diabetes (induced by streptozotocin 60 mg/kg) on lung gene expression. Wistar rats, male. At age 8 weeks control rats got IP buffer, diabetic rats got streptozotocin. At age 12 weeks animals were anesthetized and lungs removed. RNA was extracted with Trizol, and gene expression array analysis was performed using Affymetrix RAE 230A microarrays according to the directions from the manufacturer. Arrays were scanned using a Hewlett Packard Gene Array scanner, and analyzed with Affymetrix MAS 5.0 software. Expression levels reported are the output from the MAS software.
Alterations in lung gene expression in streptozotocin-induced diabetic rats.
Age, Specimen part
View SamplesNormal young adult Sprague Dawley rats (male)
Differential expression of lipid and carbohydrate metabolism genes in upper airway versus diaphragm muscle.
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View SamplesComparison of gene expression of heart (left vent) and diaphragm of normal Sprague Dawley rats, young adult
Contrast between cardiac left ventricle and diaphragm muscle in expression of genes involved in carbohydrate and lipid metabolism.
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View SamplesGlucocorticoids are a well recognized and common cause of muscle atrophy. Glucocorticoid-induced atrophy can be prevented by testosterone, but the molecular mechanisms underlying such protection have not been described. Thus, the global effects of testosterone on dexamethasone-induced changes in gene expression were evaluated in rat gastrocnemius muscle using Affymetrix 230_2 DNA microarrays. Gene expression was analyzed after 7 days administration of dexamethasone, dexamethasone plus testosterone, or vehicle. Effects of these agents on weights of gastrocnemius muscles from these animals has been reported (1. Zhao W, Pan J, Zhao Z, Wu Y, Bauman WA, and Cardozo CP. Testosterone protects against dexamethasone-induced muscle atrophy, protein degradation and MAFbx upregulation. J Steroid Biochem Mol Biol 110: 125-129, 2008.) Dexamethasone changed expression of 876 probe sets by at least 2-fold, of which 474 probe sets were changed by at least two fold in the opposite direction in the dexamethasone plus testosterone group (genes in opposition). Major biological themes represented by genes in opposition included IGF-1 signaling, protein synthesis, myogenesis and muscle development, and ubiquitin conjugases and ligases. Testosterone blocked increased expression of DDIT4 and eIF4EBP1, FOXO1 and of the p85 regulatory subunit of the IGF-1 receptor, while preventing decreased expression of IRS-1. Testosterone blocked decreased expression of LXR and suppressed upregulation of C/EBP beta and delta. Testosterone prevented increase expression of Cdkn1A (p21) and decrease expression of cyclins B and D, as well as many other changes that would be expected to reduce cell cycle progression. Testosterone prevented increased expression of muscle development factors Csrp3 and Mbn1 and blocked reduced expression of Wnt4. These data suggest that testosterone blocks multiple changes in gene expression that, collectively, would otherwise downregulate molecular signals that promote protein synthesis and muscle hypertrophy and that stimulate muscle protein catabolism.
REDD1 is a major target of testosterone action in preventing dexamethasone-induced muscle loss.
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View SamplesCell fate is defined by specific transcriptional program. Here, we provide evidence that the transcriptional coactivator, Mediator 1 (MED1), is critical in determining the cell fate of ectodermal epithelia. MED1 ablation disrupted enamel formation and generated hair adjacent to the incisors. Deletion of MED1 altered the differentiation of dental epithelia to one expressing epidermal and hair genes similar to the skin. The cellular switch from dental to epidermal/hair lineage was characterized by abnormalities in MED1 deficient dental epithelial stem cells residing in cervical loop. MED1 deficiency caused a failure of dental epithelial stem cells to commit to the dental stratum intermedium regulated by Notch signaling. Instead, MED1 deficient cells retained stem cell potentials expressing Sox2. These cells were eventually adopted an epidermal fate probably through calcium provided through capillary networks, which is originally utilized for enamel formation. Our results demonstrate that MED1 regulates Sox2/Notch1 regulated cell lineage determination in dental epithelia. Our study also shows a potential to regenerate hairs by using genetically engineered dental tissues or cells outside of the skin.
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Age, Specimen part
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