Proper mitochondrial function plays a central role in cellular metabolism. Various diseases as well as aging are associated with diminished mitochondrial function. Previously, we identified 19 miRNAs putatively involved in the regulation of mitochondrial metabolism in skeletal muscle, a highly metabolically active tissue. In the present study, these 19 miRNAs were individually silenced in C2C12 myotubes using antisense oligonucleotides, followed by measurement of the expression of 27 genes known to play a major role in regulating mitochondrial metabolism. Based on the outcomes, we then focused on miR-382-5p and identified pathways affected by its silencing using microarrays, investigated protein expression and studied cellular respiration. Silencing of miRNA-382-5p significantly increased the expression of several genes involved in mitochondrial dynamics and -biogenesis. Microarray analysis of C2C12 myotubes silenced for miRNA-382-5p revealed a collective downregulation of mitochondrial ribosomal proteins and respiratory chain proteins. This effect was accompanied by an imbalance between mitochondrial proteins encoded by the nuclear and mitochondrial DNA (1.35-fold, p<0.01) and an induction of HSP60 protein (1.31-fold, p<0.05), indicating activation of the mitochondrial unfolded protein response (mtUPR). Furthermore, silencing of miR-382-5p reduced basal oxygen consumption rate by 14% (p<0.05) without affecting mitochondrial content, pointing towards a more efficient mitochondrial function as a result of improved mitochondrial quality control. Taken together, silencing of miR-382-5p induces a mitonuclear protein imbalance and activates the mtUPR in skeletal muscle, a phenomenon that was previously associated with improved longevity.
MicroRNA-382 silencing induces a mitonuclear protein imbalance and activates the mitochondrial unfolded protein response in muscle cells.
Specimen part, Cell line
View SamplesBackground: The prevalence of type 2 diabetes has increased dramatically in recent decades. Increasing brown adipose tissue (BAT) mass and activity has recently emerged as an interesting approach to not only increase energy expenditure, but also improve glucose homeostasis. BAT can be recruited by prolonged cold exposure in lean, healthy humans. Here, we tested whether cold acclimation could have therapeutic value for patients with type 2 diabetes by improving insulin sensitivity. Methods: Eight type 2 diabetic patients (age 59.35.8 years, BMI 29.83.2 kg/m2) followed a cold acclimation protocol, consisting of intermittent cold exposure (6 hours/day, 14-14.5 C) for 12 consecutive days. Before and after cold acclimation, cold-induced BAT activity was assessed by [18F]FDG-PET/CT scanning, insulin sensitivity at thermoneutrality by a hyperinsulinemic-euglycemic clamp, and muscle and WAT biopsies were taken. Results: Cold-induced BAT activity was low, but increased in all patients upon cold acclimation (SUV from 0.400.29 to 0.630.78, p<0.05). Interestingly, insulin sensitivity showed a very pronounced 40% increase upon cold acclimation (glucose rate of disappearance from 14.94.1 to 20.56.9 mol kg-1 min-1, p<0.05). A 40% increase in insulin sensitivity cannot be explained by BAT glucose uptake, in fact basal skeletal muscle GLUT4 content and translocation was markedly increased after cold acclimation, without effects on insulin signaling or AMPk activation. Conclusions: Regular mild cold exposure has marked effects on insulin sensitivity, which are accompanied by small increases in BAT activity and more pronounced effects on skeletal muscle. These data suggest a novel therapeutic option for the treatment of type 2 diabetes.
Short-term cold acclimation improves insulin sensitivity in patients with type 2 diabetes mellitus.
Subject
View SamplesEffects of treatment with Nimodipine on N9 cells
Nimodipine fosters remyelination in a mouse model of multiple sclerosis and induces microglia-specific apoptosis.
Treatment
View SamplesC-peptide exerts beneficial effects on glomerular hyperfiltration in type I diabetic patients. As C-peptide localizes to the nucleus, we investigated the transcriptional activities of C-peptide in proximal tubular cells isolated from diabetic rats.
Early transcriptional regulation by C-peptide in freshly isolated rat proximal tubular cells.
Specimen part, Treatment
View SamplesSeasonal allergic rhinitis (SAR) is a complex disease that is caused by many interacting genes and environmental factors. It is also an excellent model disease for clinical studies; it is common, it is seasonal, and since it takes place in the nasal cavity it can be studied in vivo non-invasively. Furthermore, the key disease cell, the Th2 cell is known. We study SAR using allergen-challenged CD4+ cells from allergic patients.
Highly interconnected genes in disease-specific networks are enriched for disease-associated polymorphisms.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Systems biology of the IMIDIA biobank from organ donors and pancreatectomised patients defines a novel transcriptomic signature of islets from individuals with type 2 diabetes.
Age
View SamplesPancreatic islet beta cell failure causes type 2 diabetes (T2D). The IMIDIA consortium has used a strategy entailing a stringent comparative transcriptomics analysis of islets isolated enzymatically or by laser microdissection from two large cohorts of non-diabetic (ND) and T2D organ donors (OD) or partially pancreatectomized patients (PPP). This work led to the identification of a signature of genes that were differentially expressed between T2D and ND regardless of the sample type (OD or PPP). This signature includes 19 genes, of which 9 have never been previously reported to be differentially expressed in T2D islets. The PPP cohort also includes samples from individuals with impaired glucose tolerance (IGT) or recent onset diabetes associated with a pancreatic exocrine disorder (T3cD). Notably, none of the 19 signature genes of T2D islets were significantly dysregulated in islets of subjects with IGT or T3cD, suggesting that their changed expression reflects beta cell deterioration rather than a deficit preceding it.
Systems biology of the IMIDIA biobank from organ donors and pancreatectomised patients defines a novel transcriptomic signature of islets from individuals with type 2 diabetes.
Age
View SamplesPancreatic islet beta cell failure causes type 2 diabetes (T2D). The IMIDIA consortium has used a strategy entailing a stringent comparative transcriptomics analysis of islets isolated enzymatically or by laser microdissection from two large cohorts of non-diabetic (ND) and T2D organ donors (OD) or partially pancreatectomized patients (PPP). This work led to the identification of a signature of genes that were differentially expressed between T2D and ND regardless of the sample type (OD or PPP). This signature includes 19 genes, of which 9 have never been previously reported to be differentially expressed in T2D islets. The PPP cohort also includes samples from individuals with impaired glucose tolerance (IGT) or recent onset diabetes associated with a pancreatic exocrine disorder (T3cD). Notably, none of the 19 signature genes of T2D islets were significantly dysregulated in islets of subjects with IGT or T3cD, suggesting that their changed expression reflects beta cell deterioration rather than a deficit preceding it.
Systems biology of the IMIDIA biobank from organ donors and pancreatectomised patients defines a novel transcriptomic signature of islets from individuals with type 2 diabetes.
Age
View Samples