Hypomorphic Mutation in PGC1beta causes mitochondrial dysfunction and liver insulin resistance
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE6210 | GEO | 2007/01/01
SECONDARY ACCESSION(S): PRJNA100627
REPOSITORIES: GEO
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Project description:PGC1beta is a transcriptional coactivator that potently stimulates mitochondrial biogenesis and respiration of cells. Here, we have generated mice lacking exons 3 to 4 of the Pgc1beta gene (PGC1beta E3,4-/E3,4- mice). These mice express a mutant protein that has reduced coactivation activity on a subset of transcription factors, including ERRalpha, a major target of PGC1beta in the induction of mitochondrial gene expression. The mutant mice have reduced expression of OXPHOS genes and mitochondrial dysfunction in liver and skeletal muscle as well as elevated liver triglycerides. Euglycemic-hyperinsulinemic clamp and insulin signaling studies show that PGC1beta mutant mice have normal skeletal muscle response to insulin, but have hepatic insulin resistance. These results demonstrate that PGC1beta is required for normal expression of OXPHOS genes and mitochondrial function in liver and skeletal muscle. Importantly, these abnormalities do not cause insulin resistance in skeletal muscle but cause substantially reduced insulin action in the liver. Experiment Overall Design: Gene expression levels in liver tissue and quadriceps muscle were compared between WT/Control and PGC1beta mutant tissue. Total RNA was extracted from liver and skeletal muscle using RNAeasy kit (Qiagen, Valencia, CA), according to the manufacturerâ??s instructions. Synthesis of cRNA, hybridization and scanning of the Affymetrix Murine 430 2.0 chip was performed by Dana Farber Cancer Institute Microarray Core Facility. The microarray data was analyzed by Clustering Analysis using the d-Chip software (Li and Wong, 2001).
2009-04-24 | E-GEOD-6210 | biostudies-arrayexpress
Project description:Recently, abnormalities in mitochondrial oxidative phosphorylation (OXPHOS) have been implicated in the pathogenesis of skeletal muscle insulin resistance in type 2 diabetes. In the present study, we hypothesized that decreased expression of OXPHOS genes could be of similar importance for insulin resistance in the polycystic ovary syndrome (PCOS). Using the HG-U133 Plus 2.0 expression array from Affymetrix, we analyzed gene expression in skeletal muscle from obese women with PCOS (n=16) and age- and body mass index-matched control women (n=13) metabolically characterized by euglycemic-hyperinsulinemic clamp and indirect calorimetry. To identify pathways of importance for the pathogenesis of insulin resistance in PCOS, we performed biological pathway analysis using Gene Set Enrichment Analysis (GSEA 1.0) and Gene Microarray Pathway Profiler (GenMAPP 2.0). The expression of 9 genes, selected according to biological relevance, was evaluated by quantitative real time PCR (q-RT-PCR). Women with PCOS were characterized by fasting hyperinsulinemia and impaired insulin-stimulated glucose disposal - caused by reduced glucose oxidation and storage - as well as impaired suppression of lipid oxidation (all P<0.01). GSEA and GenMAPP both revealed the same set of genes involved in OXPHOS, which was also the most downregulated biological pathway (P<0.01). These results were confirmed by q-RT-PCR of six genes from the OXPHOS gene set as well as three transcription factors known to regulate the transcription of these genes. Our results, for the first time, provide evidence for an association between insulin resistance and impaired mitochondrial oxidative metabolism in skeletal muscle in women with PCOS. This may contribute to the increased risk of type 2 diabetes observed in these women Experiment Overall Design: 16 insulin resistant PCOS patients of fertile age were matched to 13 healthy control subjects.
2008-06-15 | E-GEOD-6798 | biostudies-arrayexpress
Project description:Recently, abnormalities in mitochondrial oxidative phosphorylation (OXPHOS) have been implicated in the pathogenesis of skeletal muscle insulin resistance in type 2 diabetes. In the present study, we hypothesized that decreased expression of OXPHOS genes could be of similar importance for insulin resistance in the polycystic ovary syndrome (PCOS). Using the HG-U133 Plus 2.0 expression array from Affymetrix, we analyzed gene expression in skeletal muscle from obese women with PCOS (n=16) and age- and body mass index-matched control women (n=13) metabolically characterized by euglycemic-hyperinsulinemic clamp and indirect calorimetry. To identify pathways of importance for the pathogenesis of insulin resistance in PCOS, we performed biological pathway analysis using Gene Set Enrichment Analysis (GSEA 1.0) and Gene Microarray Pathway Profiler (GenMAPP 2.0). The expression of 9 genes, selected according to biological relevance, was evaluated by quantitative real time PCR (q-RT-PCR). Women with PCOS were characterized by fasting hyperinsulinemia and impaired insulin-stimulated glucose disposal - caused by reduced glucose oxidation and storage - as well as impaired suppression of lipid oxidation (all P<0.01). GSEA and GenMAPP both revealed the same set of genes involved in OXPHOS, which was also the most downregulated biological pathway (P<0.01). These results were confirmed by q-RT-PCR of six genes from the OXPHOS gene set as well as three transcription factors known to regulate the transcription of these genes. Our results, for the first time, provide evidence for an association between insulin resistance and impaired mitochondrial oxidative metabolism in skeletal muscle in women with PCOS. This may contribute to the increased risk of type 2 diabetes observed in these women Keywords: PCOS, DNA microarray, global pathway analysis, mitochondrial oxidative metabolism, qantitative real time PCR, insulin resistance, skeletal muscle
2007-10-20 | GSE6798 | GEO
Project description:Insulin resistance is a common metabolic abnormality in women with PCOS and leads to an elevated risk of type 2 diabetes. Studies have shown that thiazolidinediones (TZD) improve metabolic disturbances in PCOS patients. We hypothesized that the effect of TZD in PCOS is in part mediated by changes in the transcriptional profile of muscle favoring insulin sensitivity. Using Affymetrix microarrays, we examined the effect of pioglitazone (30 mg/day for 16 weeks) on gene expression in skeletal muscle of 10 obese women with PCOS metabolically characterized by a euglycemic-hyperinsulinemic clamp. Moreover, we explored gene expression changes between these PCOS patients before treatment and 13 healthy control women. Treatment with pioglitazone improved insulin-stimulated total, oxidative and non-oxidative glucose metabolism, and reduced fasting serum insulin (all p < 0.05). Global pathway analysis using Gene Map Annotator and Pathway Profiler (GenMAPP 2.1) and Gene Set Enrichment Analysis (GSEA 2.0.1) revealed a significant upregulation of genes involved in mitochondrial oxidative phosphorylation (OXPHOS), ribosomal proteins, mRNA processing reactome, translation factors, and proteasome complexes in PCOS patients after pioglitazone therapy. Quantitative real-time PCR suggested that upregulation of OXPHOS genes was mediated by an increase in PGC-1M-NM-1 expression (p < 0.05). Expression of genes involved in ribosomal proteins and OXPHOS was down-regulated in PCOS patients before treatment compared to matched healthy women using GenMAPP 2.1 and GSEA 2.1. These data indicate that pioglitazone therapy restores insulin sensitivity in part by a coordinated upregulation of genes involved in mitochondrial oxidative metabolism and protein biosynthesis in skeletal muscle of PCOS. These transcriptional effects of pioglitazone therapy may contribute to prevent the onset of type 2 diabetes in these women. Experiment Overall Design: Ten obese women of reproductive age with PCOS participated in the study to test the effect of pioglitazone therapy (data set 1). To test if pioglitazone ameliorate existing defects in PCOS patients, the expression profile of the 10 PCOS patients before treatment were compared to the same cohort of 13 control subjects (data set 2).
2008-11-14 | E-GEOD-8157 | biostudies-arrayexpress
Project description:Type 2 diabetes (T2D) and obesity are strongly associated with low natriuretic peptide (NP) plasma levels and impaired NP signaling with a down-regulation of NP guanylyl cyclase receptor-A (GCA) in skeletal muscle and adipose tissue. However, no study has so far provided evidence for a causal link between ANP/GCA deficiency and T2D development. Here, we show that both ANP and GCA deficiency in mice promotes metabolic disturbances and prediabetes. In GCA haploinsufficient mice, skeletal muscle insulin resistance is associated with altered mitochondrial function and impaired endurance running capacity. Muscle RNA-seq analyses reveal down-regulation of various gene sets related to mitochondrial protein complexes and translation. Despite normal mitochondrial content, GCA haploinsufficient mice exhibit increased proton leak and reduced content of mitochondrial oxidative phosphorylation (OXPHOS) proteins. Using various clinical studies and cohorts, we further show that GCA is related to various metabolic traits in T2D and positively correlates with markers of oxidative capacity in human skeletal muscle. Altogether, these results indicate that ANP/GCA signaling controls muscle mitochondrial integrity and oxidative capacity in vivo and plays a causal role in the development of T2D.
2024-11-05 | GSE245048 | GEO
Project description:Skeletal muscle insulin resistance, decreased phosphatidylinositol 3-kinase (PI3K) activation and altered mitochondrial function are hallmarks of type 2 diabetes. We created mice with a muscle-specific knockout of p110α or p110β, the two major catalytic subunits of PI3K. We find that mice with muscle-specific knockout of p110α, but not p110β, display impaired muscle insulin signaling and reduced muscle size due to enhanced proteasomal and autophagic activity. Despite insulin resistance and muscle atrophy, M-p110αKO mice show decreased serum myostatin, increased mitochondrial mass, increased mitochondrial fusion visualized by intravital microscopy, and increased PGC1α expression, especially PCG1α2 and PCG1α3. This leads to enhanced mitochondrial oxidative capacity, striking increases in muscle NADH content, and higher muscle free radical release measured in vivo using pMitoTimer reporter. Thus, p110α is the dominant catalytic isoform of PI3K in muscle in control of insulin sensitivity and muscle mass, and has a unique role in mitochondrial homeostasis in skeletal muscle.
2019-03-12 | GSE124394 | GEO
Project description:The homeodomain transcription factor Prep1 was previously shown to regulate insulin sensitivity. Our aim was to study the specific role of Prep1 for the regulation of energy metabolism in skeletal muscle. Muscle specific ablation of Prep1 resulted in increased expression of respiratory chain subunits. This finding was consistent with an increase in mitochondrial enzyme activity without affecting mitochondrial volume fraction as assessed by electron microscopy. Metabolic phenotyping revealed no differences in daily energy expenditure or body composition. However, during treadmill exercise challenge, Prep1 ablation resulted in a higher maximal oxidative capacity and better endurance. Elevated PGC-1α expression was identified as a cause for increased mitochondrial capacity in Prep1-ablated mice. Prep1 stabilizes p160 Mybbp1a, a known inhibitor of PGC-1α activity. Thereby, P160 protein levels were significantly lower in muscle of Prep1-ablated mice. By a ChIPseq approach, PREP1-binding sites in genes encoding mitochondrial components (e.g. Ndufs2) were identified that might be responsible for elevated OXPHOS proteins in the muscle of Prep1 nullmutants. These results suggest that Prep1 exhibits additional direct effects on regulation of mitochondrial proteins. We therefore conclude that Prep1 is a regulator of oxidative phosphorylation components via direct and indirect mechanisms. Consequence of Prep1 ablation in skeletal muscle was investigated in Prep1deltaSM mice and compared to Prep1 flox mice, both on C57BL/6 background. 4 mice of each genotype were used to extract RNA from the tibialis anterior muscle.
2014-01-01 | E-GEOD-52424 | biostudies-arrayexpress
Project description:Total RNA was isolated from 3 WT and 3 ERRalpha null hearts and independent hybridizations were performed using MOE430 2.0 microarrays. Expression profiling was conducted to determine changes in gene expression in hearts lacking ERRa. The expression of genes involved in heart and muscle development, muscle contraction, lipid metabolism, OxPhos, protein metabolism and transcription were affected by the loss of ERRa. Experiment Overall Design: 3 hearts from WT and 3 hearts from ERRalpha-null mice were used in the study. The expression of genes in the ERRalpha KO hearts were compared to the reference WT hearts.
2007-11-10 | E-GEOD-7196 | biostudies-arrayexpress
Project description:Impaired estrogen production and action are associated with obesity and insulin resistance in male males however the tissues critical for estrogen action in the maintenance of metabolic homeostasis remain inadequately understood. Moreover, the cell specific target genes and molecular actions of estrogen in males remain unknown. We generated male mice with a muscle-specific ERa knockout (MERKO) to determine the role of this hormone nuclear receptor in controlling metabolic function and insulin action in skeletal muscle. Male MERKO mice became insulin resistant with age and accumulated more adipose tissue than floxed control mice. Skeletal muscle was distinguished by enlarged hyper-fused mitochondria that produced increased amounts of superoxide, and this was associated with enhanced proinflammatory signaling. The striking mitochondrial phenotype was accompanied by reduced protein abundance of electron transport chain proteins and the mitochondrial biogenesis marker Pgc1a. Muscle from MERKO mice showed imbalanced protein abundance of mitochondrial fission-fusion proteins most notably marked reductions in total DRP1, MFN1, and OPA1 were observed compared with f/f control. To recapitulate the reduction in DRP1 protein leading to impairment in mitochondrial fission, we generated mice with a muscle-specific heterozygous deletion in Drp1 (mDrp1+/-). mDrp1+/- mice phenocopied the aberrant muscle mitochondrial morphology and dysfunction of the MERKO mice and developed insulin resistance with age. Skeletal muscle ERa is critical for the maintenance of mitochondrial function and metabolic homeostasis in male mice.
2017-09-12 | GSE103722 | GEO
Project description:Skeletal muscle mitochondrial dysfunction is secondary to T2DM and can be improved by long-term regular exercise training Mitochondrial dysfunction has long been implicated to play a causative role in development of type 2 diabetes (T2DM). However, a growing number of recent studies provide data that mitochondrial dysfunction is a consequence of T2DM development. The aim of our study is to clarify in further detail the causal role of mitochondrial dysfunction in T2DM by a comprehensive ex vivo analysis of mitochondrial function combined with global gene expression analysis in muscle of pre-diabetic newly diagnosed untreated T2DM subjects and long-standing insulin treated T2DM subjects compared with age- and BMI-matched controls. In addition, we assessed the impact of long-term interval exercise training on physical activity performance, mitochondrial function and glycemic control in long-standing insulin-treated T2DM subjects. Ex vivo mitochondrial density, quality and functioning was comparable between pre-diabetic subjects and matched controls, however, gene expression analysis showed a switch from carbohydrate toward lipids as energy source in pre-diabetes subjects. In contrast, long-term insulin treated T2DM subjects had slightly decreased mitochondrial density and ex vivo function. Expression of Krebs cycle and OXPHOS related genes were decreased, indicating a decreased capacity to use lipids as an energy source. The insulin-treated T2DM subjects had a lower physical activity level than pre-diabetic and normoglycemic subjects. A 52 weeks exercise training of these subjects increased submaximal oxidative efficiency, increased in vivo PCr recovery rate, as well as mildly increased in vitro mitochondrial function. Gene expression of β-oxidation, Krebs cycle and OXPHOS-related genes was increased. Our data demonstrate that mitochondrial dysfunction is rather a consequence than a causative factor in T2DM development as it was only detected in overt diabetes and not in early diabetes. Regular exercise training stabilized exogenous insulin requirement and improved mitochondrial functioning, fatty acid oxidation and general physical work load capacity in long-standing insulin-treated T2DM subjects. As such, the present study shows for the first time that long-term exercise interventions are beneficial in this group of complex diabetes patient and may prevent further metabolic deterioration. Insulin-treated T2DM subjects before and after 52 weeks of exercise training (T2DM_0 and T2DM_52), normoglycemic controls (NGT) and pre-diabetes subjects (IGT) and were selected. RNA was extracted from skeletal muscle biopsies and hybridized on Affymetrix microarrays.
2010-11-29 | E-GEOD-19420 | biostudies-arrayexpress