We here used whole blood gene expression profiling to differentiate SSc patients from healthy controls (HC) and to identify a specific gene expression and predictive genes for SSc-overlap syndromes.
Whole blood gene expression profiling distinguishes systemic sclerosis-overlap syndromes from other subsets.
Specimen part, Disease, Disease stage
View SamplesAims/hypothesis: While lipid deposition in skeletal muscle is considered to be involved in obesity-associated insulin resistance, neutral intramyocellular lipid (IMCL) accumulation per se does not necessarily induce insulin resistance. We previously demonstrated that overexpression of the lipid droplet coat protein perilipin 2 augments intramyocellular lipid content while improving insulin sensitivity. Another member of the perilipin family, perilipin 5 (PLIN5), is predominantly expressed in oxidative tissues like skeletal muscle. Here we investigated the effects of PLIN5 overexpression in comparison with effects of PLIN2 on skeletal muscle lipid levels, gene expression profiles and insulin sensitivity. Methods: Gene electroporation was used to overexpress PLIN5 in tibialis anterior muscle of rats fed a high fat diet. Eight days after electroporation, insulin-mediated glucose uptake in skeletal muscle was measured by means of a hyperinsulinemic euglycemic clamp. Electron microscopy, fluorescence microscopy and lipid extractions were performed to investigate IMCL accumulation. Gene expression profiles were obtained using microarrays. Results: TAG storage and lipid droplet size increased upon PLIN5 overexpression. Despite the higher IMCL content, insulin sensitivity was not impaired and DAG and acylcarnitine levels were unaffected. In contrast to the effects of PLIN2 overexpression, microarray data analysis revealed a gene expression profile favoring FA oxidation and improved mitochondrial function. Conclusions/interpretation: Both PLIN2 and PLIN5 increase neutral IMCL content without impeding insulin-mediated glucose uptake. As opposed to the effects of PLIN2 overexpression, overexpression of PLIN5 in skeletal muscle promoted expression of a cluster of genes under control of PPAR and PGC1 involved in FA catabolism and mitochondrial oxidation.
Overexpression of PLIN5 in skeletal muscle promotes oxidative gene expression and intramyocellular lipid content without compromising insulin sensitivity.
Sex, Age, Specimen part, Treatment
View Samples1,2-unsaturated pyrrolizidine alkaloids (PA) are plant metabolites predominantly occurring in the plant families Asteraceae and Boraginaceae. Acute and chronic PA poisoning causes severe hepatotoxicity. So far, the molecular mechanisms of PA toxicity are not well understood. To analyze its mode of action, primary human hepatocytes were exposed to a non-cytotoxic dose of 100 M of four structurally different PA: echimidine, heliotrine, senecionine, senkirkine. Changes in mRNA expression were analyzed by a whole genome microarray. Employing cut-off values with a |fold change| of 2 and a q-value of 0.01, data analysis revealed numerous changes in gene expression. In total, 4556, 1806, 3406 and 8623 genes were regulated by echimidine, heliotrine, senecione and senkirkine, respectively. 1304 genes were identified as commonly regulated. PA affected pathways related to cell cycle regulation, cell death and cancer development. The transcription factors TP53, MYC, NFB and NUPR1 were predicted to be activated upon PA treatment. Furthermore, gene expression data showed a considerable interference with lipid metabolism and bile acid flow. The associated transcription factors FXR, LXR, SREBF1/2, and PPAR// were predicted to be inhibited. In conclusion, though structurally different, all four PA significantly regulated a great number of genes in common. This proposes similar molecular mechanisms, although the extent seems to differ between the analyzed PA as reflected by the potential hepatotoxicity and individual PA structure.
Disturbance of gene expression in primary human hepatocytes by hepatotoxic pyrrolizidine alkaloids: A whole genome transcriptome analysis.
No sample metadata fields
View SamplesThe NF-B pathway is a master regulator of inflammatory processes and is implicated in insulin resistance and pancreatic beta cell dysfunction in the metabolic syndrome. While canonical NF-B signaling is well studied, there is little information on the divergent non-canonical NF-B pathway in the context of pancreatic islet dysfunction in diabetes. Here, we demonstrate that pharmacological activation of the non-canonical NF-B inducing kinase (NIK) disrupts glucose homeostasis in zebrafish in vivo. Further, we identify NIK as a critical negative regulator of beta cell function as pharmacological NIK activation results in impaired glucose-stimulated insulin secretion in mouse and human islets. NIK levels are elevated in pancreatic islets isolated from diet-induced obese (DIO) mice, which exhibit increased processing of non-canonical NF-B components p100 to p52, and accumulation of RelB. Tumor necrosis factor (TNF) and receptor activator of NF-B ligand (RANKL), two ligands associated with diabetes, induce NIK in islets. Mice with constitutive beta cell intrinsic NIK activation present impaired insulin secretion with DIO. NIK activation triggers the non-canonical NF-B transcriptional network to induce genes identified in human type 2 diabetes genome-wide association studies linked to beta cell failure. These studies reveal that NIK contributes a central mechanism for beta cell failure in diet-induced obesity.
Nuclear factor κB-inducing kinase activation as a mechanism of pancreatic β cell failure in obesity.
Specimen part, Treatment
View SamplesType 2 diabetes is characterized by excessive lipid storage in skeletal muscle. Excessive intramyocellular lipid storage exceeds intracellular needs and induces lipotoxic events ultimately contributing to the development of insulin resistance. Lipid droplet (LD)-coating proteins may control proper lipid storage in skeletal muscle. Perilipin 2 (PLIN2/ADRP) is one of the most abundantly expressed LD-coating proteins in skeletal muscle. Here we examined the role of PLIN2 in myocellular lipid handling and insulin sensitivity by investigating the effects of in vitro PLIN2 knockdown and in vitro and in vivo overexpression. PLIN2 knockdown decreased LD formation and triacylglycerol storage, marginally increased FA oxidation, and increased incorporation of palmitate into diacylglycerols and phospholipids. PLIN2 overexpression in vitro increased intramyocellular TAG storage paralleled with improved insulin sensitivity. In vivo muscle-specific PLIN2 overexpression resulted in increased LD accumulation and blunted the high-fat diet-induced increase of OXPHOS protein content. Diacylglycerol levels were unchanged, while ceramide levels were increased. Despite the increased intramyocellular lipid accumulation, PLIN2 overexpression improved skeletal muscle insulin sensitivity. We conclude that PLIN2 is essential for lipid storage in skeletal muscle by enhancing the partitioning of excess FAs towards triacylglycerol storage in LDs thereby blunting lipotoxicity-associated insulin resistance.
Perilipin 2 improves insulin sensitivity in skeletal muscle despite elevated intramuscular lipid levels.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Comparative transcriptome analysis of human skeletal muscle in response to cold acclimation and exercise training in human volunteers.
Sex, Disease, Subject, Time
View SamplesBackground: Cold acclimation and exercise training were previously shown to increase peripheral insulin sensitivity in human volunteers with type 2 diabetes. Although cold is a potent activator of brown adipose tissue, the increase in peripheral insulin sensitivity by cold is largely mediated by events occurring in skeletal muscle and at least partly involves GLUT4 translocation, as is also observed for exercise training. Results: To investigate if cold acclimation and exercise training overlap in the molecular adaptive response in skeletal muscle, we performed transcriptomics analysis on vastus lateralis muscle collected from human subjects before and after 10 days of cold acclimation, as well as before and after a 12-week exercise training intervention. Methods: Cold acclimation altered the expression of 756 genes (422 up, 334 down, P<0.01), while exercise training altered the expression of 665 genes (444 up, 221 down, P<0.01). Principal Component Analysis, Venn diagram, similarity analysis and Rank–rank Hypergeometric Overlap all indicated significant overlap between cold acclimation and exercise training in upregulated genes, but not in downregulated genes. Overlapping gene regulation was especially evident for genes and pathways associated with extracellular matrix remodeling. Interestingly, the genes most highly induced by cold acclimation were involved in contraction and in signal transduction between nerve and muscle cells, while no significant changes were observed in genes and pathways related to insulin signaling or glucose metabolism. Conclusions: Overall, our results indicate that cold acclimation and exercise training have overlapping effects on gene expression in human skeletal muscle, but strikingly these overlapping genes are designated to pathways related to cell remodeling rather than metabolic pathways.
Comparative transcriptome analysis of human skeletal muscle in response to cold acclimation and exercise training in human volunteers.
Sex, Disease, Subject, Time
View SamplesBackground: Cold acclimation and exercise training were previously shown to increase peripheral insulin sensitivity in human volunteers with type 2 diabetes. Although cold is a potent activator of brown adipose tissue, the increase in peripheral insulin sensitivity by cold is largely mediated by events occurring in skeletal muscle and at least partly involves GLUT4 translocation, as is also observed for exercise training. Results: To investigate if cold acclimation and exercise training overlap in the molecular adaptive response in skeletal muscle, we performed transcriptomics analysis on vastus lateralis muscle collected from human subjects before and after 10 days of cold acclimation, as well as before and after a 12-week exercise training intervention. Methods: Cold acclimation altered the expression of 756 genes (422 up, 334 down, P<0.01), while exercise training altered the expression of 665 genes (444 up, 221 down, P<0.01). Principal Component Analysis, Venn diagram, similarity analysis and Rank–rank Hypergeometric Overlap all indicated significant overlap between cold acclimation and exercise training in upregulated genes, but not in downregulated genes. Overlapping gene regulation was especially evident for genes and pathways associated with extracellular matrix remodeling. Interestingly, the genes most highly induced by cold acclimation were involved in contraction and in signal transduction between nerve and muscle cells, while no significant changes were observed in genes and pathways related to insulin signaling or glucose metabolism. Conclusions: Overall, our results indicate that cold acclimation and exercise training have overlapping effects on gene expression in human skeletal muscle, but strikingly these overlapping genes are designated to pathways related to cell remodeling rather than metabolic pathways.
Comparative transcriptome analysis of human skeletal muscle in response to cold acclimation and exercise training in human volunteers.
Sex, Disease, Subject, Time
View SamplesRNA sequencing data for replicates of E347 driver control, E347 neuronal ablation per Shi dominant-negative expression and activation per NachBac expression to identify differences in RNA abundancy Overall design: E347 driver control, E347 neuronal ablation per Shi dominant-negative expression and activation per NachBac expression
Coordination between Drosophila Arc1 and a specific population of brain neurons regulates organismal fat.
Specimen part, Subject
View SamplesData for replicate Drn1-TAP and Dbr1-TAP CLIP-seq experiments to identify RNA-protein interactions Overall design: Drn1-TAP and Dbr1-TAP CLIP-seq
A homolog of lariat-debranching enzyme modulates turnover of branched RNA.
Disease, Subject
View Samples