Dynamin-related protein 1 regulates substrate oxidation in skeletal muscle by stabilizing cellular and mitochondrial calcium dynamics
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ABSTRACT:
PROVIDER: PRJNA684136 | ENA |
REPOSITORIES: ENA
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Project description:Mitochondria undergo continuous cycles of fission and fusion to promote inheritance, regulate quality control, and mitigate organelle stress. More recently, this process of mitochondrial dynamics has been demonstrated to be highly sensitive to nutrient supply, ultimately conferring bioenergetic plasticity to the organelle. However, whether regulators of mitochondrial dynamics play a causative role in nutrient regulation remains unclear. In this study, we generated a cellular loss-of-function model for dynamin-related protein 1 (DRP1), the primary regulator of outer membrane mitochondrial fission. Loss of DRP1 (shDRP1) resulted in extensive ultrastructural and functional remodeling of mitochondria, characterized by pleomorphic enlargement, increased electron density of the matrix, and defective NADH and succinate oxidation. Despite increased mitochondrial size and volume, shDRP1 cells exhibited reduced cellular glucose uptake and mitochondrial fatty acid oxidation. Untargeted transcriptomic profiling revealed severe downregulation of genes required for cellular and mitochondrial calcium homeostasis, inhibition of ATP-stimulated calcium flux, and impaired substrate oxidation stimulated by calcium levels. The insights obtained herein suggest that DRP1 regulates fatty acid oxidation by altering whole-cell and mitochondrial calcium dynamics. These findings are relevant to the targetability of mitochondrial fission and have clinical relevance in the identification of treatments for fission-related pathologies such as hereditary neuropathies, inborn errors in metabolism, cancer, and chronic diseases.
2021-09-13 | GSE162983 | GEO
Project description: Not available
| S-EPMC8498465 | biostudies-literature
Project description:We previously identified a small molecule, UM101, predicted to bind to the substrate-binding groove of MAPK14/p38a near the binding site of the proinflammatory substrate, MAPK-activated protein kinase (MK2). UM101 exhibited anti-inflammatory, endothelial-stabilizing, and lung-protective effects. We developed an analog of UM101, GEn-1124, with improved aqueous stability and p38a binding affinity. Compared with UM101, GEn-1124 has 60-fold greater p38a binding affinity as measured by Surface Plasmon Resonance (SPR), 66-fold greater aqueous solubility, enhanced barrier-stabilizing activity in thrombin-stimulated human pulmonary artery endothelial cells (hPAEC) in vitro, and greater lung protection in a mouse models of acute lung injury (ALI). GEn-1124 reduced lung injury and improved survival in a mouse model of ALI induced by intratracheal LPS instillation and exposure to febrile-range hyperthermia (FRH) from 10% to 40% and in a mouse influenza pneumonia model from 0% to 50%. RNASeq and pathway analysis of gene expression in TNFa-treated hPAEC showed that the gene-modifying effects of GEn-1124 were much more restricted to TNFa-inducible genes than SB203580. Gene expression pathway analysis, confocal immunofluorescence analysis of p38a and MK2 subcellular trafficking, and SPR analysis of phosphorylated p38a:MK2 binding affinity supports a novel mechanism of action. GEn-1124 destabilizes the phosphorylated p38a:MK2 complex, dissociates nuclear export of phosphorylated p38a and MK2, thereby promoting intranuclear phosphorylated p38a retention and intranuclear signaling, and accelerating inactivation of p38-free cytosolic MK2 by unopposed phosphatases.
2024-04-01 | GSE262079 | GEO
Project description:The Hippo signalling pathway effector Yap positively regulates adult skeletal muscle mass. However, the biological processes that are modulated by Yap in skeletal muscle remain elusive. Using an integrated transcriptomics and proteomics approach, we define the transcriptional programme regulated by Yap in adult skeletal muscle and demonstrate that Yap is a regulator of metabolic substrate utilisation. Inhibition of Yap in mammalian skeletal muscle results in increased, but incomplete, oxidation of fatty acids and features of lipotoxicity. In line with these findings, we demonstrate that Yap abundance is reduced in the skeletal musculature of obese db/db mice, and in muscle biopsies from obese, insulin-resistant humans where YAP levels positively correlate with whole-body metabolic flexibility. Increasing Yap abundance in the striated muscle of db/db mice attenuated the accumulation of fat mass and development of hepatic steatosis. Our findings demonstrate a vital role for Yap in skeletal muscle as a mediator of metabolic substrate utilisation. Modulating Yap activity in skeletal muscle warrants consideration as part of comprehensive approaches to treat metabolic disease.
2021-02-18 | GSE144137 | GEO
Project description:The Hippo signalling pathway effector Yap positively regulates adult skeletal muscle mass. However, the biological processes that are modulated by Yap in skeletal muscle remain elusive. Using an integrated transcriptomics and proteomics approach, we define the transcriptional programme regulated by Yap in adult skeletal muscle and demonstrate that Yap is a regulator of metabolic substrate utilisation. Inhibition of Yap in mammalian skeletal muscle results in increased, but incomplete, oxidation of fatty acids and features of lipotoxicity. In line with these findings, we demonstrate that Yap abundance is reduced in the skeletal musculature of obese db/db mice, and in muscle biopsies from obese, insulin-resistant humans where YAP levels positively correlate with whole-body metabolic flexibility. Increasing Yap abundance in the striated muscle of db/db mice attenuated the accumulation of fat mass and development of hepatic steatosis. Our findings demonstrate a vital role for Yap in skeletal muscle as a mediator of metabolic substrate utilisation. Modulating Yap activity in skeletal muscle warrants consideration as part of comprehensive approaches to treat metabolic disease.
2021-02-18 | GSE144135 | GEO
Project description:Ferroptosis is an iron-dependent form of cell death driven by biochemical and metabolic alterations resulting in oxidation within the lipid compartment. Calcium is a potent signaling molecule ascribed to diverse cellular processes including migration, neurotransmitter function, and cell death. Here we elucidate a crucial link between calcium homeostasis and ferroptotic cell death through the identification of the tetraspanin MS4A15. Ectopic MS4A15 expression specifically protects against ferroptosis by depleting endoplasmic reticulum stores. In an unexpected connection, prolonged calcium dysregulation stimulates fundamental remodeling to ferroptosis-resistant monounsaturated and plasmalogen lipid species. Application of this discovery revealed that augmenting luminal calcium sensitizes cancer cell lines previously refractory to ferroptosis. This finding provides a unique mechanistic basis for ferroptosis sensitivity and resolves a long-standing query into the role of calcium in oxidative cell death. Manipulating calcium homeostasis offers an unprecedented strategy for overcoming therapy resistance in cancer.
2021-10-09 | GSE160574 | GEO
Project description:The Dynamin-related GTPase, Drp1 (encoded by Dnm1l) plays a central role in mitochondrial fission and is requisite for numerous cellular processes however its role in oxidative metabolism remains unclear. Herein, we show that among human tissues, skeletal muscle exhibits the strongest correlations with the DNM1L gene. Knockdown of Drp1 (Drp1-KD) promoted mitochondrial hyperfusion in the muscle of male mice. Reduced fatty acid oxidation and accumulation of intramyocellular lipids along with increased muscle succinate was observed in Drp1-KD muscle. Muscle Drp1-KD reduced Complex II assembly and activity as a consequence of diminished mitochondrial translocation of succinate dehydrogenase assembly factor 2 (Sdhaf2). Restoration of Sdhaf2, normalized Complex II activity and lipid oxidation in Drp1-KD myocytes. Drp1 appears critical in maintaining mitochondrial Complex II assembly and fatty acid oxidation, suggesting a mechanistic link between mitochondrial morphology and skeletal muscle lipid metabolism which is of clinical significance in combatting metabolic diseases.
2024-01-26 | GSE248081 | GEO
Project description:Skeletal muscle excitation-contraction (EC) coupling is independent of calcium influx. In fact alternative splicing of the voltage-gated calcium channel CaV1.1 actively suppresses calcium currents in mature muscle. Why this might be necessary is not known. However, splicing defects causing aberrant expression of the calcium-conducting embryonic CaV1.1e splice variant correlate with muscle weakness in myotonic dystrophy. Here we deleted CaV1.1 exon 29 in mice. The continued expression of CaV1.1e resulted in increased calcium influx during EC coupling and spontaneous calcium sparks. While overall motor performance was normal, muscle force was reduced, endurance enhanced, and the fiber type composition shifted toward slower fibers. In contrast, oxidative enzyme activity and the mitochondrial content declined. Together with the dysregulation of key regulators of the slow program these findings indicate that limiting calcium influx during skeletal muscle EC coupling is important for the calcium signalâs secondary function in the activity-dependent regulation of fiber type composition. Differential gene expression between soleus and EDL muscle fibres from wildtype and Cav1.1 delta E29 mice.
2016-04-01 | E-GEOD-67803 | biostudies-arrayexpress
Project description:The role of peroxisome proliferator-activated receptor M-NM-4 (PPARM-NM-4) activation on global gene expression and mitochondrial fuel utilization were investigated in human myotubes. Only 21 genes were up-regulated and 3 genes were down-regulated after activation by the PPARM-NM-4 agonist GW501516. Pathway analysis showed up-regulated mitochondrial fatty acid oxidation, TCA cycle and cholesterol biosynthesis. GW501516 increased oleic acid oxidation and mitochondrial oxidative capacity by 2-fold. Glucose uptake and oxidation were reduced, but total substrate oxidation was not affected, indicating a fuel switch from glucose to fatty acid. Cholesterol biosynthesis was increased, but lipid biosynthesis and mitochondrial content were not affected. This study confirmed that the principal effect of PPARM-NM-4 activation was to increase mitochondrial fatty acid oxidative capacity. Our results further suggest that PPARM-NM-4 activation reduced glucose utilization through a switch in mitochondrial substrate preference by up-regulating pyruvate dehydrogenase kinase isozyme 4 and genes involved in lipid metabolism and fatty acid oxidation. Keywords: Expression profiling by array Human myotubes from four donors were exposed to a PPARM-NM-4 agonist or control for 96 h after which gene expression was profiled.
2014-05-23 | E-GEOD-40789 | biostudies-arrayexpress
Project description:Skeletal muscle excitation-contraction (EC) coupling is independent of calcium influx. In fact alternative splicing of the voltage-gated calcium channel CaV1.1 actively suppresses calcium currents in mature muscle. Why this might be necessary is not known. However, splicing defects causing aberrant expression of the calcium-conducting embryonic CaV1.1e splice variant correlate with muscle weakness in myotonic dystrophy. Here we deleted CaV1.1 exon 29 in mice. The continued expression of CaV1.1e resulted in increased calcium influx during EC coupling and spontaneous calcium sparks. While overall motor performance was normal, muscle force was reduced, endurance enhanced, and the fiber type composition shifted toward slower fibers. In contrast, oxidative enzyme activity and the mitochondrial content declined. Together with the dysregulation of key regulators of the slow program these findings indicate that limiting calcium influx during skeletal muscle EC coupling is important for the calcium signal’s secondary function in the activity-dependent regulation of fiber type composition.
2016-04-01 | GSE67803 | GEO