We used microarray technology to profile mRNA expression in the skeletal muscle of normal (NGT), glucose intolerant (IGT) and type 2 diabetic (DM) subjects. Groups were classified using WHO criteria and, importantly, the DM group were free of anti hypoglycaemic medication for one week prior to biopsy.
Integration of microRNA changes in vivo identifies novel molecular features of muscle insulin resistance in type 2 diabetes.
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Adipose tissue abundance relies partly on the factors that regulate adipogenesis, i.e. proliferation and differentiation of adipocytes. While the transcriptional program that initiates adipogenesis is well-known, the importance of microRNAs in adipogenesis is less well studied. We thus set out to investigate whether miRNAs would be actively modulated during adipogenesis and obesity. Several models exist to study adipogenesis in vitro, of which the cell line 3T3-L1 is probably the most well known, albeit not the most physiologically appropriate. We used a microarray strategy to provide a global profile of miRNAs in brown and white primary murine adipocytes (prior to and following differentiation) and evaluated the similarity of the responses to non-primary cell models, through literature data-mining. We found 65 miRNAs regulated during in vitro adipogenesis in primary adipocytes. When we compared our primary adipocyte profiles with those of cell lines reported in the literature, we found a high degree of difference in adipogenesis-regulated miRNAs. We evaluated the expression of 10 of our adipogenesis-regulated miRNAs using real-time qPCR and then selected 5 miRNAs that showed robust expression levels and profiled these by qPCR in subcutaneous adipose tissue of 20 humans with a range of body mass indices (BMI, range=21-48). Of the miRNAs tested, mir-21 was both highly expressed in human adipose tissue and positively correlated with BMI (R2=0.49, p<0.001). In conclusion, we provide the preliminary analysis of miRNAs important for primary cell in vitro adipogenesis and find that the inflammation-associated miRNA, mir-21, is up-regulated in subcutaneous adipose tissue in human obesity.
Gene-chip studies of adipogenesis-regulated microRNAs in mouse primary adipocytes and human obesity.
The mechanisms underlying muscle wasting in cancer patients remain poorly understood, and consequently there remains an unmet clinical need for new biomarkers and treatment strategies.
Suppression of skeletal muscle turnover in cancer cachexia: evidence from the transcriptome in sequential human muscle biopsies.
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Rectus abdominis muscle biopsies were obtained from 65 upper gastrointestinal (UGI) cancer patients during open surgery and RNA profiling was performed on a subset of this cohort (n=21) using the Affymetrix U133+2 platform with the aim of identifying biomarkers of cancer related muscle wasting.
Using transcriptomics to identify and validate novel biomarkers of human skeletal muscle cancer cachexia.
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Septic patients treated in the intensive care unit (ICU) often develop multiple organ failure including persistent skeletal muscle dysfunction which results in the patients protracted recovery process. We have demonstrated that muscle mitochondrial enzyme activities are impaired in septic ICU patients resulting in decreased cellular energy which will interfere with muscle function and metabolism. Here we use detailed phenotyping and genomics to elucidate mechanisms leading to these impairments. Methodology/Principle Findings Utilising biopsy material from seventeen patients and ten age-matched controls we demonstrate that neither mitochondrial in vivo protein synthesis nor expression of mitochondrial genes are compromised. Indeed, there was partial activation of the mitochondrial biogenesis pathway involving NRF2?/GABP and its target genes TFAM, TFB1M and TFB2M yet clearly this failed to maintain mitochondrial function. We therefore utilised transcript profiling and pathway analysis of ICU patient skeletal muscle to generate insight into the molecular defects driving loss of muscle function and metabolic homeostasis. Gene ontology analysis of Affymetrix analysis demonstrated substantial loss of muscle specific genes, a global oxidative stress response related to most probably cytokine signalling, altered insulin related signalling and a substantial overlap between patients and muscle wasting/inflammatory animal models. MicroRNA 21 processing appeared defective suggesting that post-transcriptional protein synthesis regulation is altered by disruption of tissue microRNA expression. Finally, we were able to demonstrate that the phenotype of skeletal muscle in ICU patients is not merely one of inactivity, it appears to be an actively remodelling tissue, influenced by several mediators, all of which may be open to manipulation with the aim to improve clinical outcome. Conclusions/Significance This first combined protein and transcriptome based analysis of human skeletal muscle obtained from septic patients demonstrated that losses of mitochondria and muscle mass are accompanied by sustained protein synthesis (anabolic process) while dysregulation of transcription programmes appears to fail to compensate for increased damage and proteolysis. Our analysis identified both validated and novel clinically tractable targets to manipulate these failing processes and pursuit of these could lead to new potential treatments.
Dysregulation of mitochondrial dynamics and the muscle transcriptome in ICU patients suffering from sepsis induced multiple organ failure.
Human liver progenitor cells (LPCs) show therapeutic potential, however, their in vitro culture results in inadequate function and phenotypic instability reflecting incomplete understanding of in vivo processes. Foetal LPCs capable of differentiation to a hepatocyte phenotype were isolated and mRNA expression profiling carried out using Affymetrix HGU133plus2 microarrays. This was compared to profiles from mature human hepatocytes and human embryonic stem cells undergoing hepatocytic differentiation. Foetal LPCs exhibit a distinct molecular profile consistent with a stem cell signature, cell division, and some liver-specific functions.
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The hypoxia response contributes to radio and chemo-resistance in cancer cells. Our previous work has shown that the nitric oxide donating non-steroidal anti-inflammatory drug (NO-NSAID) NO-sulindac is a potent inhibitor of the hypoxia response in prostate cancer cells and leads to increased susceptibilty to radiation. In this study we used microarrays to investigated the global impact of NO-sulindac on the hypoxia response in prostate cancer cells with a view to determining the mechanism of action.
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Targeted interference of sin3a-tgif1 function by SID decoy treatment inhibits WNT signaling and invasion in triple negative breast cancer cells. MDA-MB-231 cells were treated with scrambled SID control, 2.5M SID peptide or untreated for 24h.
Targeted interference of SIN3A-TGIF1 function by SID decoy treatment inhibits Wnt signaling and invasion in triple negative breast cancer cells.
Specimen partView Samples