Restoring age-related loss of the lactate receptor GPR81 improves mitochondrial function and mitigates skeletal muscle aging
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE325224 | GEO | 2026/06/01
REPOSITORIES: GEO
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Project description:Muscle weakness and atrophy are clinical hallmarks of myotonic dystrophy type 1 (DM1). Muscle stem cells, which contribute to skeletal muscle growth and repair, are also affected in this disease. However, the molecular mechanisms leading to this defective activity and the impact on the disease severity are still elusive. Here, we explored through an unbiased approach the molecular signature leading to myogenic cell defects in DM1. Single cell RNAseq data revealed the presence of a specific subset of DM1 myogenic cells expressing a senescence signature, characterized by the high expression of genes related to senescence-associated secretory phenotype (SASP). This profile was confirmed using different senescence markers in vitro and in situ. Accumulation of intranuclear RNA foci in senescent cells, suggest that RNA-mediated toxicity contribute to senescence induction. High expression of IL-6, a prominent SASP cytokine, in the serum of DM1 patients was identified as a biomarker correlating with muscle weakness and functional capacity limitations. Drug screening revealed that the BCL-XL inhibitor (A1155463), a senolytic drug, can specifically target senescent DM1 myoblasts to induce their apoptosis and reduce their SASP. Removal of senescent cells re-established the myogenic function of the non-senescent DM1 myoblasts, which displayed improved proliferation and differentiation capacity in vitro; and enhanced engraftment following transplantation in vivo. Altogether this study presents a well-defined senescent molecular signature in DM1 untangling part of the pathological mechanisms observed in the disease; additionally, we demonstrate the therapeutic potential of targeting these defective cells with senolytics to restore myogenesis.
2023-05-05 | GSE208360 | GEO
Project description:Whether muscle mitochondrial dysfunction is the cause or consequence of metabolic disorders remains controversial. Herein, we demonstrate that inhibition of mitochondrial ATP synthase in muscle in vivo alters whole-body lipid homeostasis. Mice with restrained activity of the enzyme presented intrafiber lipid droplets, dysregulation of acyl-glycerides and higher visceral adipose tissue deposits, causing these animals to be prone to insulin resistance. This mitochondrial energy crisis increase lactate production, prevents fatty acid β-oxidation, and forces the catabolism of branched-chain amino acids (BCAA) to provide acetyl-CoA for de novo lipid synthesis. In turn, muscle acetyl-CoA accumulation feeds back to oxidative phosphorylation dysfunction through the acetylation-dependent inhibition of respiratory complex II that results in augmented ROS production. Finally, by screening 702 FDA-approved drugs, we identified edaravone as a potent mitochondrial antioxidant and enhancer. The edaravone-driven restoration of ROS and lipid homeostasis in skeletal muscle reestablished insulin sensitivity, thus suggesting that muscular mitochondrial perturbations are a direct cause in the setting of metabolic disorders and repurposing edaravone as a potential treatment for these diseases.
2020-07-06 | PXD017621 | Pride
Project description:Whether muscle mitochondrial dysfunction is the cause or consequence of metabolic disorders remains controversial. Herein, we demonstrate that inhibition of mitochondrial ATP synthase in muscle in vivo alters whole-body lipid homeostasis. Mice with restrained activity of the enzyme presented intrafiber lipid droplets, dysregulation of acyl-glycerides and higher visceral adipose tissue deposits, causing these animals to be prone to insulin resistance. This mitochondrial energy crisis increase lactate production, prevents fatty acid β-oxidation, and forces the catabolism of branched-chain amino acids (BCAA) to provide acetyl-CoA for de novo lipid synthesis. In turn, muscle acetyl-CoA accumulation feeds back to oxidative phosphorylation dysfunction through the acetylation-dependent inhibition of respiratory complex II that results in augmented ROS production. Finally, by screening 702 FDA-approved drugs, we identified edaravone as a potent mitochondrial antioxidant and enhancer. The edaravone-driven restoration of ROS and lipid homeostasis in skeletal muscle reestablished insulin sensitivity, thus suggesting that muscular mitochondrial perturbations are a direct cause in the setting of metabolic disorders and repurposing edaravone as a potential treatment for these diseases.
2020-07-06 | PXD017683 | Pride
Project description:Whether muscle mitochondrial dysfunction is the cause or consequence of metabolic disorders remains controversial. Herein, we demonstrate that inhibition of mitochondrial ATP synthase in muscle in vivo alters whole-body lipid homeostasis. Mice with restrained activity of the enzyme presented intrafiber lipid droplets, dysregulation of acyl-glycerides and higher visceral adipose tissue deposits, causing these animals to be prone to insulin resistance. This mitochondrial energy crisis increase lactate production, prevents fatty acid β-oxidation, and forces the catabolism of branched-chain amino acids (BCAA) to provide acetyl-CoA for de novo lipid synthesis. In turn, muscle acetyl-CoA accumulation feeds back to oxidative phosphorylation dysfunction through the acetylation-dependent inhibition of respiratory complex II that results in augmented ROS production. Finally, by screening 702 FDA-approved drugs, we identified edaravone as a potent mitochondrial antioxidant and enhancer. The edaravone-driven restoration of ROS and lipid homeostasis in skeletal muscle reestablished insulin sensitivity, thus suggesting that muscular mitochondrial perturbations are a direct cause in the setting of metabolic disorders and repurposing edaravone as a potential treatment for these diseases.
2020-07-06 | PXD017678 | Pride
Project description:Myosteatosis is the pathological accumulation of lipid that occurs in conjunction with atrophy and fibrosis following skeletal muscle injury or disease. Little is known about the mechanisms by which lipid accumulates in myosteatosis, but many studies have demonstrated the degree of lipid infiltration negatively correlates with muscle function and regeneration. Our goal was to identify biochemical pathways that lead to muscle dysfunction and lipid accumulation in injured rotator cuff muscles, a model that demonstrates severe myosteatosis. Adult rats were subjected to a massive tear to the rotator cuff musculature. After a period of either 0 (healthy control), 10, 30, or 60 days, muscles were prepared for RNA sequencing, shotgun lipidomics, metabolomics, biochemical measures, electron microscopy, and muscle fiber contractility. Following rotator cuff injury, there was a decrease in muscle fiber specific force production that was lowest at 30d. There was a dramatic time dependent increase in triacylglyceride content. Interestingly, genes related to not only triacylglyceride synthesis, but also lipid oxidation were largely downregulated over time. Using bioinformatics techniques, we identified that biochemical pathways related to mitochondrial dysfunction and reactive oxygen species were considerably increased in muscles with myosteatosis. Long chain acyl-carnitines and L-carnitine, precursors to beta-oxidation, were depleted following rotator cuff tear. Electron micrographs showed injured muscles displayed large lipid droplets within mitochondria at early time points, and an accumulation of peripheral segment mitochondria at all time points. Several markers of oxidative stress were elevated following rotator cuff tear. The results from this study suggest that the accumulation of lipid in myosteatosis is not a result of canonical lipid synthesis, but occurs due to decreased lipid oxidation in mitochondria. A failure in lipid utilization by mitochondria would ultimately cause an accumulation of lipid even in the absence of increased synthesis. Further study will identify whether this process is required for the onset of myosteatosis.
2018-08-29 | GSE103266 | GEO
Project description:Type 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. C2C12 cells (mouse myoblast cell line) were treated with fatty acids and effects of knockdown of Perilipin 2 by siRNA were studied by gene expression profiling.
2012-06-08 | E-GEOD-38590 | biostudies-arrayexpress
Project description:Aims/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 M-bM-^@M-^S in comparison with effects of PLIN2 M-bM-^@M-^S 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 PPARM-NM-1 and PGC1M-NM-1 involved in FA catabolism and mitochondrial oxidation. Rats received a high fat diet for 3 weeks; 2 weeks after start of the diet intervention Plin5 (OXPAT) or Plin2 (ADRP) were overexpressed in either the right or left tibialis anterior muscle. One week later pooled tibialis anterior muscle samples were analysed on microarrays.
2013-01-29 | E-GEOD-43832 | biostudies-arrayexpress
Project description:Muscle is a target of growth hormone (GH) action and a major contributor to whole body metabolism. Little is known about how GH regulates metabolic process in muscle or the extent to which muscle contributes to changes in whole body substrate metabolism during GH treatment. To identify GH-responsive genes that regulate substrate metabolism in muscle, we studied six hypopituitary men who underwent whole body metabolic measurement and muscle biopsies before and after two weeks of GH treatment (0.5mg/day). Transcript profiles of four subjects were analysed using Affymetrix GeneChips. Serum insulin-like growth factor I (IGF-I), procollagens I and III were measured by RIA. GH increased serum IGF-I, procollagens I and III, enhanced whole body lipid oxidation, reduced carbohydrate oxidation, and stimulated protein synthesis. It induced gene expression of IGF-I and collagens in muscle. GH reduced expression of several enzymes regulating lipid oxidation and energy production. It reduced calpain 3, increased ribosomal protein L38 expression, and displayed mixed effects on genes encoding myofibrillar proteins. It increased expression of circadian gene CLOCK, and reduced that of PERIOD. In summary, GH exerted concordant effects on muscle expression and blood levels of IGF-I and collagens. It induced changes in genes regulating protein metabolism in parallel with a whole body anabolic effect. The discordance between muscle gene expression profiles and metabolic responses suggests that muscle is unlikely to contribute to GH-induced stimulation of whole body energy and lipid metabolism. GH may regulate circadian function in muscle by modulating circadian gene expression with possible metabolic consequences.
2008-01-31 | E-TABM-206 | biostudies-arrayexpress
Project description:Branched-chain amino acids (BCAA) have emerged as predictors of type 2 diabetes (T2D). However, their potential role in the pathogenesis of insulin resistance and T2D remains unclear. By integrating data from skeletal muscle gene expression and metabolomic analyses, we demonstrate evidence for perturbation in BCAA metabolism and fatty acid oxidation in skeletal muscle from insulin-resistant humans. Experimental modulation of BCAA flux in cultured cells alters fatty acid oxidation in parallel. Furthermore, heterozygosity for the BCAA metabolic enzyme methylmalonyl-CoA mutase (MUT) alters muscle lipid metabolism in vivo, resulting in increased muscle triacylglycerol (TAG) accumulation and increased body weight after high-fat feeding. Together, our results demonstrate that impaired muscle BCAA catabolism may contribute to the development of insulin resistance by reducing fatty acid oxidation and increasing TAG accumulation.
2017-02-09 | GSE66766 | 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