An insulin-stimulated proteolytic mechanism links energy expenditure with glucose uptake
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE134846 | GEO | 2020/07/23
REPOSITORIES: GEO
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Project description:Huntington’s Disease (HD) is an inherited neurodegenerative disease caused by a glutamine repeat expansion in huntingtin protein. Transcriptional deregulation and altered energy metabolism have been implicated in HD pathogenesis. We report here that mutant huntingtin causes disruption of mitochondrial function by inhibiting expression of PGC-1a, a transcriptional coactivator that regulates several metabolic processes including mitochondrial biogenesis and respiration. Mutant huntingtin represses PGC-1a gene transcription by associating with the promoter and interfering with the CREB/TAF4-dependent transcriptional pathway critical for the regulation of PGC-1a gene expression. Crossbreeding of PGC-1a knockout mice with HD knock-in mice leads to increased neurodegeneration of striatal neurons and motor abnormalities in the HD mice. Importantly, expression of PGC-1a partially reverses the toxic effects of mutant huntingtin in cultured striatal neurons. Moreover, lentiviral-mediated delivery of PGC-1a in the striatum provides neuroprotection in the transgenic HD mice. These studies suggest a key role for PGC-1a in the control of energy metabolism in the early stages of HD pathogenesis. Keywords: PGC-1a, striatum
2006-10-05 | GSE5786 | GEO
Project description:Calorie restriction (CR) is a dietary intervention that extends lifespan and healthspan in a variety of organisms. CR improves mitochondrial energy production, fuel oxidation and reactive oxygen species scavenging in skeletal muscle and other tissues, and these processes are thought to be critical to the benefits of CR. PGC-1a is a transcriptional coactivator that regulates mitochondrial function and is induced by CR. Consequently, many of the mitochondrial and metabolic benefits of CR are attributed to increased PGC-1a activity. To test this model for the first time, we examined the metabolic and mitochondrial response to CR in mice lacking skeletal muscle PGC-1a (MKO). Surprisingly, MKO mice demonstrated a normal improvement in glucose homeostasis in response to CR, indicating that skeletal muscle PGC-1a is dispensable for the whole-body benefits of CR. In contrast, gene expression profiling and electron microscopy demonstrated that PGC-1a is required for the full CR-induced increases in mitochondrial gene expression and mitochondrial density in skeletal muscle. These results demonstrate that PGC-1a is a major regulator of the mitochondrial response to CR in skeletal muscle, but surprisingly show that neither PGC-1a nor mitochondrial biogenesis in skeletal muscle are required for the metabolic benefits of CR.
2012-02-04 | GSE34773 | GEO
Project description:The peroxisome proliferator-activated receptor c coactivator 1 (PGC-1) proteins are key regulators of cellular bioenergetics and are accordingly expressed in tissues with a high energetic demand. For example, PGC-1a and PGC-1b control organ function of brown adipose tissue, heart, brain, liver and skeletal muscle. Surprisingly, despite their prominent role in the control of mitochondrial biogenesis and oxidative metabolism, expression and function of the PGC-1 coactivators in the retina, an organ with one of the highest energy demands per tissue weight, are completely unknown. Moreover, the molecular mechanisms that coordinate energy production with repair processes in the damaged retina remain enigmatic. In the present study, we thus investigated the expression and function of the PGC-1 coactivators in the healthy and the damaged retina. We show that PGC-1a and PGC-1b are found at high levels in different structures of the mouse retina, most prominently in the photoreceptors. Furthermore, PGC-1a knockout mice suffer from a striking deterioration in retinal morphology and function upon detrimental light exposure. Gene expression studies revealed dysregulation of all major pathways involved in retinal damage and apoptosis, repair and renewal in the PGC-1a knockouts. The light-induced increase in apoptosis in vivo in the absence of PGC-1a was substantiated in vitro, where overexpression of PGC-1a evoked strong anti-apoptotic effects. Finally, we found that retinal levels of PGC-1 expression are reduced in different mouse models for retinitis pigmentosa. We demonstrate that PGC-1a is a central coordinator of energy production and, importantly, all of the major processes involved in retinal damage and subsequent repair. Together with the observed dysregulation of PGC-1a and PGC-1b in retinitis pigmentosa mouse models, these findings thus imply that PGC-1a might be an attractive target for therapeutic approaches aimed at retinal degeneration diseases.
2016-04-15 | GSE80265 | GEO
Project description:Calorie restriction (CR) is a dietary intervention that extends lifespan and healthspan in a variety of organisms. CR improves mitochondrial energy production, fuel oxidation and reactive oxygen species scavenging in skeletal muscle and other tissues, and these processes are thought to be critical to the benefits of CR. PGC-1a is a transcriptional coactivator that regulates mitochondrial function and is induced by CR. Consequently, many of the mitochondrial and metabolic benefits of CR are attributed to increased PGC-1a activity. To test this model for the first time, we examined the metabolic and mitochondrial response to CR in mice lacking skeletal muscle PGC-1a (MKO). Surprisingly, MKO mice demonstrated a normal improvement in glucose homeostasis in response to CR, indicating that skeletal muscle PGC-1a is dispensable for the whole-body benefits of CR. In contrast, gene expression profiling and electron microscopy demonstrated that PGC-1a is required for the full CR-induced increases in mitochondrial gene expression and mitochondrial density in skeletal muscle. These results demonstrate that PGC-1a is a major regulator of the mitochondrial response to CR in skeletal muscle, but surprisingly show that neither PGC-1a nor mitochondrial biogenesis in skeletal muscle are required for the metabolic benefits of CR. Control (FLOX) and PGC-1a skeletal muscle specific knock out (MKO) mice were placed on a control diet [C] or a calorie restriction diet [CR] for 12 weeks. RNA was isolated from TA/EDL muscles for microarray analysis. The following numbers of mice were analyzed from each group: C FLOX: n = 6; C MKO: n = 7; CR FLOX: n = 6; CR MKO: n = 7. Mice were mixed C57/BL6 and 129 background.
2012-02-04 | E-GEOD-34773 | biostudies-arrayexpress
Project description:Huntington's Disease (HD) is an inherited neurodegenerative disease caused by a glutamine repeat expansion in huntingtin protein. Transcriptional deregulation and altered energy metabolism have been implicated in HD pathogenesis. We report here that mutant huntingtin causes disruption of mitochondrial function by inhibiting expression of PGC-1a, a transcriptional coactivator that regulates several metabolic processes including mitochondrial biogenesis and respiration. Mutant huntingtin represses PGC-1a gene transcription by associating with the promoter and interfering with the CREB/TAF4-dependent transcriptional pathway critical for the regulation of PGC-1a gene expression. Crossbreeding of PGC-1a knockout mice with HD knock-in mice leads to increased neurodegeneration of striatal neurons and motor abnormalities in the HD mice. Importantly, expression of PGC-1a partially reverses the toxic effects of mutant huntingtin in cultured striatal neurons. Moreover, lentiviral-mediated delivery of PGC-1a in the striatum provides neuroprotection in the transgenic HD mice. These studies suggest a key role for PGC-1a in the control of energy metabolism in the early stages of HD pathogenesis. Experiment Overall Design: Total RNA was extracted from striata of 3 pgc1 KO mice and 3 littermate controls using the RNeasy Mini Kit (Qiagen) according to manufacturer's protocol. Samples were analyzed using RNA 6000 Nano LabChip kit on a 2100 Bioanalyzer (Agilent Technologies) to ensure integrity of RNA.
2007-11-13 | E-GEOD-5786 | biostudies-arrayexpress
Project description:The following abstract from the submitted manuscript describes the major findings of this work. The metabolic development of high energy-utilizing organs such as the heart involves mitochondrial proliferation at birth followed by a maturation process during the postnatal period. Conditional gene targeting was used in mice to explore the role of the PPARgamma coactivator 1 (PGC-1) coactivators during postnatal development and in adult heart. Marked mitochondrial derangements were observed in hearts of PGC-1a/b-deficient mice during the postnatal period, including fragmentation and elongation associated with the development of a lethal cardiomyopathy. The expression of multiple genes involved in mitochondrial fusion and fission was downregulated in hearts of PGC-1a/b-deficient mice. PGC-la was shown to activate transcription of the mitofusin 1 (Mfn1) gene by coactivating the estrogen-related receptor a (ERRa) upon a highly conserved element. Surprisingly, PGC-1a/b deficiency did not alter cardiac function or general mitochondrial density and myocyte distribution in adult heart. However, transcriptional profiling and mitochondrial function studies demonstrated that the PGC-1 coactivators are required for full respiratory capacity and high level expression of nuclear- and mitochondrial-encoded genes involved in mitochondrial energy transduction and oxidative phosphorylation pathways in adult heart. These results unveil distinct developmental stage-specific transcriptional programs involved in the maturation and maintenance of mitochondria. RNA from five PGC-1a-/- and five PGC-1a-/-bf/f/MerCre mice was analyzed.
2014-01-13 | E-GEOD-43798 | biostudies-arrayexpress
Project description:To identify mediators of obesity-linked reductions in PGC-1, we tested the effects of cellular nutrients in C2C12 myotubes. While overnight exposure to high insulin, glucose, glucosamine, or amino acids had no effect, saturated fatty acids (FA) potently reduced PGC-1a and b mRNA expression. Keywords: Nutrient Effect
2007-01-18 | GSE6766 | GEO
Project description:PGC-1α (Peroxisome proliferator-activated receptor gamma coactivator-1alpha) coactivators regulate adaptive gene expression in response to challenges such as cold exposure, fasting, or physical exercise to balance energy supply and demand. Transcription of a single PGC-1α gene produces different isoforms (e.g. PGC-1α1 to α4) with different biological functions. We aimed to characterize the nuclear interactome for each PGC-1α variant, in particular the transcription factors they bind to regulate gene expression. This was done by generating GST-fusions of all PGC-1a variants, expressed in an insect cell system. These were used to capture associated protein complexes from HeLa nuclear extracts.
2022-03-01 | PXD009232 | Pride
Project description:The following abstract from the submitted manuscript describes the major findings of this work. The metabolic development of high energy-utilizing organs such as the heart involves mitochondrial proliferation at birth followed by a maturation process during the postnatal period. Conditional gene targeting was used in mice to explore the role of the PPARgamma coactivator 1 (PGC-1) coactivators during postnatal development and in adult heart. Marked mitochondrial derangements were observed in hearts of PGC-1a/b-deficient mice during the postnatal period, including fragmentation and elongation associated with the development of a lethal cardiomyopathy. The expression of multiple genes involved in mitochondrial fusion and fission was downregulated in hearts of PGC-1a/b-deficient mice. PGC-la was shown to activate transcription of the mitofusin 1 (Mfn1) gene by coactivating the estrogen-related receptor a (ERRa) upon a highly conserved element. Surprisingly, PGC-1a/b deficiency did not alter cardiac function or general mitochondrial density and myocyte distribution in adult heart. However, transcriptional profiling and mitochondrial function studies demonstrated that the PGC-1 coactivators are required for full respiratory capacity and high level expression of nuclear- and mitochondrial-encoded genes involved in mitochondrial energy transduction and oxidative phosphorylation pathways in adult heart. These results unveil distinct developmental stage-specific transcriptional programs involved in the maturation and maintenance of mitochondria.
2014-01-13 | GSE43798 | GEO
Project description:The peroxisome proliferator-activated receptor-coactivator-1α1 (PGC-1α1) regulates genes involved in energy metabolism. Increasing adipose tissue energy expenditure through PGC-1α1 activation has been suggested to be beneficial for systemic metabolism. Pharmacological PGC-1α1 activators could be valuable tools in the fight against obesity and metabolic disease. Finding such compounds has been challenging partly because PGC-1α1 is a transcriptional coactivator with no known ligand-binding activities. Importantly, PGC-1α1 activation is regulated by several mechanisms but protein stabilization is a limiting step as the protein has a short half-life under unstimulated conditions. We designed a cell-based high-throughput system to identify stabilizers of PGC-1α1 protein. Positive hits were tested for their ability to induce endogenous PGC-1α1 protein accumulation and activate target gene expression in brown adipocytes. Selected compounds were analyzed for their effects on global gene expression in brown adipocytes.
2018-02-02 | GSE107630 | GEO