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Adamopoulos KI, Sanders LM, Costes SV. NASA GeneLab derived microarray studies of Mus musculus and Homo sapiens organisms in altered gravitational conditions. NPJ Microgravity 2024; 10:49. [PMID: 38671027 PMCID: PMC11053165 DOI: 10.1038/s41526-024-00392-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 04/03/2024] [Indexed: 04/28/2024] Open
Abstract
One of the greatest challenges of humanity for deep space exploration is to fully understand how altered gravitational conditions affect human physiology. It is evident that the spaceflight environment causes multiple alterations to musculoskeletal, cardiovascular, immune and central nervous systems, to name a few known effects. To better characterize these biological effects, we compare gene expression datasets from microarray studies found in NASA GeneLab, part of the NASA Open Science Data Repository. In this review, we summarize these archived results for various tissues, emphasizing key genes which are highly reproducible in different mice or human experiments. Such exhaustive mining shows the potential of NASA Open Science data to identify and validate mechanisms taking place when mammalian organisms are exposed to microgravity or other spaceflight conditions. Our comparative meta-analysis findings highlight certain degrees of overlap and reproducibility in genes identified as differentially expressed within musculoskeletal tissues in each species across a variety of altered gravity conditions. However, the level of overlap between species was found to be significantly limited, partly attributed to the limited availability of human samples.
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Affiliation(s)
- Konstantinos I Adamopoulos
- National Technical University of Athens, School of Electrical and Computer Engineering, Biomedical Engineering Laboratory, Zografou, Athens, Greece
- Blue Marble Space Institute of Science, Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, USA
| | - Lauren M Sanders
- Blue Marble Space Institute of Science, Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, USA
- NASA Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, USA
| | - Sylvain V Costes
- NASA Space Biosciences Division, NASA Ames Research Center, Moffett Field, CA, USA.
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vanLieshout TL, Stouth DW, Hartel NG, Vasam G, Ng SY, Webb EK, Rebalka IA, Mikhail AI, Graham NA, Menzies KJ, Hawke TJ, Ljubicic V. The CARM1 transcriptome and arginine methylproteome mediate skeletal muscle integrative biology. Mol Metab 2022; 64:101555. [PMID: 35872306 PMCID: PMC9379683 DOI: 10.1016/j.molmet.2022.101555] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 07/14/2022] [Accepted: 07/15/2022] [Indexed: 11/18/2022] Open
Abstract
OBJECTIVE Coactivator-associated arginine methyltransferase 1 (CARM1) catalyzes the methylation of arginine residues on target proteins to regulate critical processes in health and disease. A mechanistic understanding of the role(s) of CARM1 in skeletal muscle biology is only gradually emerging. The purpose of this study was to elucidate the function of CARM1 in regulating the maintenance and plasticity of skeletal muscle. METHODS We used transcriptomic, methylproteomic, molecular, functional, and integrative physiological approaches to determine the specific impact of CARM1 in muscle homeostasis. RESULTS Our data defines the occurrence of arginine methylation in skeletal muscle and demonstrates that this mark occurs on par with phosphorylation and ubiquitination. CARM1 skeletal muscle-specific knockout (mKO) mice displayed altered transcriptomic and arginine methylproteomic signatures with molecular and functional outcomes confirming remodeled skeletal muscle contractile and neuromuscular junction characteristics, which presaged decreased exercise tolerance. Moreover, CARM1 regulates AMPK-PGC-1α signalling during acute conditions of activity-induced muscle plasticity. CONCLUSIONS This study uncovers the broad impact of CARM1 in the maintenance and remodelling of skeletal muscle biology.
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Affiliation(s)
| | - Derek W Stouth
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Nicolas G Hartel
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089, USA
| | - Goutham Vasam
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Sean Y Ng
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Erin K Webb
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Irena A Rebalka
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Andrew I Mikhail
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Nicholas A Graham
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089, USA
| | - Keir J Menzies
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, ON, K1H 8M5, Canada; Ottawa Institute of Systems Biology and the Centre for Neuromuscular Disease, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, 451 Smyth Rd, K1H 8M5, Ottawa, Canada
| | - Thomas J Hawke
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, ON, L8S 4L8, Canada
| | - Vladimir Ljubicic
- Department of Kinesiology, McMaster University, Hamilton, ON, L8S 4L8, Canada.
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Addicks GC, Zhang H, Ryu D, Vasam G, Green AE, Marshall PL, Patel S, Kang BE, Kim D, Katsyuba E, Williams EG, Renaud JM, Auwerx J, Menzies KJ. GCN5 maintains muscle integrity by acetylating YY1 to promote dystrophin expression. J Cell Biol 2022; 221:e202104022. [PMID: 35024765 PMCID: PMC8931935 DOI: 10.1083/jcb.202104022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 11/04/2021] [Accepted: 12/08/2021] [Indexed: 12/12/2022] Open
Abstract
Protein lysine acetylation is a post-translational modification that regulates protein structure and function. It is targeted to proteins by lysine acetyltransferases (KATs) or removed by lysine deacetylases. This work identifies a role for the KAT enzyme general control of amino acid synthesis protein 5 (GCN5; KAT2A) in regulating muscle integrity by inhibiting DNA binding of the transcription factor/repressor Yin Yang 1 (YY1). Here we report that a muscle-specific mouse knockout of GCN5 (Gcn5skm-/-) reduces the expression of key structural muscle proteins, including dystrophin, resulting in myopathy. GCN5 was found to acetylate YY1 at two residues (K392 and K393), disrupting the interaction between the YY1 zinc finger region and DNA. These findings were supported by human data, including an observed negative correlation between YY1 gene expression and muscle fiber diameter. Collectively, GCN5 positively regulates muscle integrity through maintenance of structural protein expression via acetylation-dependent inhibition of YY1. This work implicates the role of protein acetylation in the regulation of muscle health and for consideration in the design of novel therapeutic strategies to support healthy muscle during myopathy or aging.
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Affiliation(s)
- Gregory C Addicks
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Hongbo Zhang
- Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Department of Histology and Embryology, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou, China
- Laboratory of Integrative Systems Physiology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Dongryeol Ryu
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Goutham Vasam
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Alexander E Green
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
- Ottawa Institute of Systems Biology and the Éric Poulin Centre for Neuromuscular Disease, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Philip L Marshall
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Sonia Patel
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
| | - Baeki E Kang
- Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, South Korea
| | - Doyoun Kim
- Division of Therapeutics and Biotechnology, Korea Research Institute of Chemical Technology, Daejeon, South Korea
| | - Elena Katsyuba
- Laboratory of Integrative Systems Physiology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Evan G Williams
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Johan Auwerx
- Laboratory of Integrative Systems Physiology, École polytechnique fédérale de Lausanne, Lausanne, Switzerland
| | - Keir J Menzies
- Interdisciplinary School of Health Sciences, Faculty of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada
- Ottawa Institute of Systems Biology and the Éric Poulin Centre for Neuromuscular Disease, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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Tran KN, Choi JI. Mimic microgravity effect on muscle transcriptome under ionizing radiation. LIFE SCIENCES IN SPACE RESEARCH 2022; 32:96-104. [PMID: 35065767 DOI: 10.1016/j.lssr.2021.12.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/30/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Spaceflight imposes the risk of skeletal muscle atrophy for astronauts. Two main factors of a spaceflight that results in deleterious effects are microgravity and cosmic rays in outer space. To study spaceflight-induced muscle atrophy with ground-based models, we performed two models of microgravity, tail suspension and denervation, in a low dose radiation environment and studied transcriptional changes in rat soleus muscle using microarrays. Soleus muscle from rats in the denervation group had greater expression changes compared to that found in rats from the tail suspension group. However, there was a very similar pattern of expression of differentially expressed genes (DEGs) in both models. In total, we identified 144 differentially expressed genes common in both models. Our study yielded two main findings. First, a large number of genes involved in energy metabolism were transcriptionally suppressed including those involved in fatty acid transport and beta-oxidation, and oxidative phosphorylation. Second, slow-twitch contractile protein encoding genes were down-regulated while there was an up-regulation in the fast-twitch type transcription. These results were consistent with other spaceflight studies on the effects on muscle cells, hence showed the potential of our ground-based models in studying spaceflight effects. The genes that might be involved in spaceflight effects will serve as candidate genes for future studies in understanding the mechanism of spaceflight-induced muscle atrophy and result in the development of effective countermeasures.
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Affiliation(s)
- Kim Ngan Tran
- Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju 61186, Republic of Korea
| | - Jong-Il Choi
- Department of Biotechnology and Bioengineering, Chonnam National University, Gwangju 61186, Republic of Korea.
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Liang Y, Wang M, Liu Y, Wang C, Takahashi K, Naruse K. Meta-Analysis-Assisted Detection of Gravity-Sensitive Genes in Human Vascular Endothelial Cells. Front Cell Dev Biol 2021; 9:689662. [PMID: 34422812 PMCID: PMC8371407 DOI: 10.3389/fcell.2021.689662] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 07/14/2021] [Indexed: 12/18/2022] Open
Abstract
Gravity affects the function and maintenance of organs, such as bones, muscles, and the heart. Several studies have used DNA microarrays to identify genes with altered expressions in response to gravity. However, it is technically challenging to combine the results from various microarray datasets because of their different data structures. We hypothesized that it is possible to identify common changes in gene expression from the DNA microarray datasets obtained under various conditions and methods. In this study, we grouped homologous genes to perform a meta-analysis of multiple vascular endothelial cell and skeletal muscle datasets. According to the t-distributed stochastic neighbor embedding (t-SNE) analysis, the changes in the gene expression pattern in vascular endothelial cells formed specific clusters. We also identified candidate genes in endothelial cells that responded to gravity. Further, we exposed human umbilical vein endothelial cells (HUVEC) to simulated microgravity (SMG) using a clinostat and measured the expression levels of the candidate genes. Gene expression analysis using qRT-PCR revealed that the expression level of the prostaglandin (PG) transporter gene SLCO2A1 decreased in response to microgravity, consistent with the meta-analysis of microarray datasets. Furthermore, the direction of gravity affected the expression level of SLCO2A1, buttressing the finding that its expression was affected by gravity. These results suggest that a meta-analysis of DNA microarray datasets may help identify new target genes previously overlooked in individual microarray analyses.
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Affiliation(s)
- Yin Liang
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Mengxue Wang
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Yun Liu
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Chen Wang
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Ken Takahashi
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
| | - Keiji Naruse
- Department of Cardiovascular Physiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan
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Exercise as a therapy for cancer-induced muscle wasting. SPORTS MEDICINE AND HEALTH SCIENCE 2020; 2:186-194. [PMID: 35782998 PMCID: PMC9219331 DOI: 10.1016/j.smhs.2020.11.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/12/2020] [Accepted: 11/17/2020] [Indexed: 12/17/2022] Open
Abstract
Cancer cachexia is a progressive disorder characterized by body weight, fat, and muscle loss. Cachexia induces metabolic disruptions that can be analogous and distinct from those observed in cancer, obscuring both diagnosis and treatment options. Inflammation, hypogonadism, and physical inactivity are widely investigated as systemic mediators of cancer-induced muscle wasting. At the cellular level, dysregulation of protein turnover and energy metabolism can negatively impact muscle mass and function. Exercise is well known for its anti-inflammatory effects and potent stimulation of anabolic signaling. Emerging evidence suggests the potential for exercise to rescue muscle's sensitivity to anabolic stimuli, reduce wasting through protein synthesis modulation, myokine release, and subsequent downregulation of proteolytic factors. To date, there is no recommendation for exercise in the management of cachexia. Given its complex nature, a multimodal approach incorporating exercise offers promising potential for cancer cachexia treatment. This review's primary objective is to summarize the growing body of research examining exercise regulation of cancer cachexia. Furthermore, we will provide evidence for exercise interactions with established systemic and cellular regulators of cancer-induced muscle wasting.
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Ye L, Li M, Wang Z, Yang Z, Zhang J, Fang H, He Z, Wang X. Depression of Mitochondrial Function in the Rat Skeletal Muscle Model of Myofascial Pain Syndrome Is Through Down-Regulation of the AMPK-PGC-1α-SIRT3 Axis. J Pain Res 2020; 13:1747-1756. [PMID: 32765049 PMCID: PMC7367922 DOI: 10.2147/jpr.s233583] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2019] [Accepted: 05/23/2020] [Indexed: 12/11/2022] Open
Abstract
Purpose The causative mechanisms triggering myofascial pain syndrome (MPS) are still in debate. It is becoming evident that mitochondrial dysfunction may regulate pathways controlling MPS. The aim of this study was to investigate whether AMPK-PGC-1α-SIRT3 axis is associated with depression of mitochondrial function in the rat MPS model. Methods A total of 32 Sprague-Dawley rats were randomly divided into control group and experimental group. The expression level of mRNA and protein of gastrocnemius medialis (GM) was analyzed by Western blot and RT-PCR. The histopathological findings were investigated through electron microscopes in GM of all groups. Results Our results showed that MPS induces continuous depression of mitochondrial biogenesis and function via down-regulation of PGC-1α-SIRT3 axis accompanying with ATP fuel crisis as compared to control group. However, the expression level of SIRT3 mRNA did not change. Additionally, a correlated reduction of the mRNA and protein expression level of NRF-1 and TFAM, known as the downstream target of PGC-1α, suggesting further transcription of nuclear genes encoding mitochondria functional proteins for promoting mitochondria proliferation, oxidative phosphorylation and energy production is continuously depressed. Furthermore, phosphorylation extent of AMPK is also declined following MPS, and it is negatively correlated with reduction of ATP generation, suggesting that the complex network involves different inhibition in transcription, post-translational modification and a plethora of other effectors that mediate the inhibition roles. Conclusion We here suggested that the down-regulation in AMPK-PGC-1α-SIRT3 axis network may be the basis for the association between mitochondrial dysfunction and MPS, where a vicious circle further aggravates the disease symptoms with ongoing ATP energy crisis.
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Affiliation(s)
- Le Ye
- Department of Pain Management, The South Campus of Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 20025, People's Republic of China
| | - Mingli Li
- Department of Anesthesiology, The Shanghai First Rehabilitation Hospital, Shanghai 200090, People's Republic of China
| | - Zhankui Wang
- Department of Orthopedics, The First Clinical Medical College, Shaanxi University of Chinese Medicine, Xianyang, Shaanxi 712046, People's Republic of China
| | - Zhongwei Yang
- Department of Anesthesiology, Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 200127, People's Republic of China
| | - Jinyuan Zhang
- Department of Anesthesiology and Intensive Care Unit, Dongfang Hospital, Tongji University, Shanghai 200123, People's Republic of China
| | - Hongwei Fang
- Department of Anesthesiology and Intensive Care Unit, Dongfang Hospital, Tongji University, Shanghai 200123, People's Republic of China
| | - Zhenzhou He
- Department of Pain Management, The South Campus of Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 20025, People's Republic of China
| | - Xiangrui Wang
- Department of Anesthesiology and Intensive Care Unit, Dongfang Hospital, Tongji University, Shanghai 200123, People's Republic of China
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Leermakers PA, Kneppers AEM, Schols AMWJ, Kelders MCJM, de Theije CC, Verdijk LB, van Loon LJC, Langen RCJ, Gosker HR. Skeletal muscle unloading results in increased mitophagy and decreased mitochondrial biogenesis regulation. Muscle Nerve 2019; 60:769-778. [PMID: 31495926 PMCID: PMC6900132 DOI: 10.1002/mus.26702] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 09/03/2019] [Accepted: 09/03/2019] [Indexed: 12/31/2022]
Abstract
Introduction Physical inactivity significantly contributes to loss of muscle mass and performance in bed‐bound patients. Loss of skeletal muscle mitochondrial content has been well‐established in muscle unloading models, but the underlying molecular mechanism remains unclear. We hypothesized that apparent unloading‐induced loss of muscle mitochondrial content is preceded by increased mitophagy‐ and decreased mitochondrial biogenesis‐signaling during the early stages of unloading. Methods We analyzed a comprehensive set of molecular markers involved in mitochondrial‐autophagy, −biogenesis, −dynamics, and ‐content, in the gastrocnemius muscle of C57BL/6J mice subjected to 0‐ and 3‐days hind limb suspension, and in biopsies from human vastus lateralis muscle obtained before and after 7 days of one‐leg immobilization. Results In both mice and men, short‐term skeletal muscle unloading results in molecular marker patterns indicative of increased receptor‐mediated mitophagy and decreased mitochondrial biogenesis regulation, before apparent loss of mitochondrial content. Discussion These results emphasize the early‐onset of skeletal muscle disuse‐induced mitochondrial remodeling.
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Affiliation(s)
- Pieter A Leermakers
- Department of Respiratory Medicine, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Anita E M Kneppers
- Department of Respiratory Medicine, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Annemie M W J Schols
- Department of Respiratory Medicine, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Marco C J M Kelders
- Department of Respiratory Medicine, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Chiel C de Theije
- Department of Respiratory Medicine, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Lex B Verdijk
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Luc J C van Loon
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Ramon C J Langen
- Department of Respiratory Medicine, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Harry R Gosker
- Department of Respiratory Medicine, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, The Netherlands
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Buso A, Comelli M, Picco R, Isola M, Magnesa B, Pišot R, Rittweger J, Salvadego D, Šimunič B, Grassi B, Mavelli I. Mitochondrial Adaptations in Elderly and Young Men Skeletal Muscle Following 2 Weeks of Bed Rest and Rehabilitation. Front Physiol 2019; 10:474. [PMID: 31118897 PMCID: PMC6504794 DOI: 10.3389/fphys.2019.00474] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/04/2019] [Indexed: 12/21/2022] Open
Abstract
The aim of the study was to evaluate the expression levels of proteins related to mitochondrial biogenesis regulation and bioenergetics in vastus lateralis muscle biopsies from 16 elderly and 7 young people subjected to 14 days of bed-rest, causing atrophy, and subsequent 14 days of exercise training. Based on quantitative immunoblot analyses, in both groups a reduction of two key regulators of mitochondrial biogenesis/remodeling and activity, namely PGC-1α and Sirt3, was revealed during bed-rest, with a subsequent up-regulation after rehabilitation, indicating an involvement of PGC-1α-Sirt3 axis in response to the treatments. A difference was observed comparing the young and elderly subjects as, for both proteins, the abundance in the elderly was more affected by immobility and less responsive to exercise. The expression levels of TOM20 and Citrate Synthase, assayed as markers of outer mitochondrial membrane and mitochondrial mass, showed a noticeable sensitivity in the elderly group, where they were affected by bed-rest and rehabilitation recalling the pattern of PGC-1α. TOM20 and CS remained unchanged in young subjects. Single OXPHOS complexes showed peculiar patterns, which were in some cases dissimilar from PGC-1α, and suggest different influences on protein biogenesis and degradation. Overall, exercise was capable to counteract the effect of immobility, when present, except for complex V, which was markedly downregulated by bed-rest, but remained unaffected after rehabilitation, maybe as result of greater extent of degradation processes over biogenesis. Phosphorylation extent of AMPK, and its upstream activator LKB1, did not change after bed-rest and rehabilitation in either young or elderly subjects, suggesting that the activation of energy-sensing LKB1-AMPK signaling pathway was “missed” due to its transient nature, or was not triggered under our conditions. Our study demonstrates that, as far as the expression of various proteins related to mitochondrial biogenesis/remodeling, adaptations to bed-rest and rehabilitation in the two populations were different. The impact of bed-rest was greater in the elderly subjects, where the pattern (decrease after bed rest and recovery following rehabilitation) was accompanied by changes of mitochondrial mass. Modifications of protein abundance were matched with data obtained from gene expression analyses of four public human datasets focusing on related genes.
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Affiliation(s)
- Alessia Buso
- Department of Medicine, University of Udine, Udine, Italy
| | - Marina Comelli
- Department of Medicine, University of Udine, Udine, Italy
| | | | - Miriam Isola
- Department of Medicine, University of Udine, Udine, Italy
| | | | - Rado Pišot
- Institute for Kinesiology Research, Science and Research Centre, Koper, Slovenia
| | - Joern Rittweger
- Department of Pediatrics and Adolescent Medicine, University of Cologne, Cologne, Germany.,Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
| | - Desy Salvadego
- Department of Medicine, University of Udine, Udine, Italy
| | - Boštjan Šimunič
- Institute for Kinesiology Research, Science and Research Centre, Koper, Slovenia
| | - Bruno Grassi
- Department of Medicine, University of Udine, Udine, Italy.,Institute of Bioimaging and Molecular Physiology, National Research Council, Milan, Italy
| | - Irene Mavelli
- Department of Medicine, University of Udine, Udine, Italy.,INBB Istituto Nazionale Biostrutture e Biosistemi, Rome, Italy
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Salvadego D, Keramidas ME, Kölegård R, Brocca L, Lazzer S, Mavelli I, Rittweger J, Eiken O, Mekjavic IB, Grassi B. PlanHab * : hypoxia does not worsen the impairment of skeletal muscle oxidative function induced by bed rest alone. J Physiol 2018; 596:3341-3355. [PMID: 29665013 DOI: 10.1113/jp275605] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 02/16/2018] [Indexed: 12/31/2022] Open
Abstract
KEY POINTS Superposition of hypoxia on 21 day bed rest did not worsen the impairment of skeletal muscle oxidative function induced by bed rest alone. A significant impairment of maximal oxidative performance was identified downstream of cardiovascular O2 delivery, involving both the intramuscular matching between O2 supply and utilization and mitochondrial respiration. These chronic adaptations appear to be relevant in terms of exposure to spaceflights and reduced gravity habitats (Moon or Mars), as characterized by low gravity and hypoxia, in patients with chronic diseases characterized by hypomobility/immobility and hypoxia, as well as in ageing. ABSTRACT Skeletal muscle oxidative function was evaluated in 11 healthy males (mean ± SD age 27 ± 5 years) prior to (baseline data collection, BDC) and following a 21 day horizontal bed rest (BR), carried out in normoxia ( PIO2 = 133 mmHg; N-BR) and hypoxia ( PIO2 = 90 mmHg; H-BR). H-BR was aimed at simulating reduced gravity habitats. The effects of a 21 day hypoxic ambulatory confinement ( PIO2 = 90 mmHg; H-AMB) were also assessed. Pulmonary O2 uptake ( V̇O2 ), vastus lateralis fractional O2 extraction (changes in deoxygenated haemoglobin + myoglobin concentration, Δ[deoxy(Hb + Mb)]; near-infrared spectroscopy) and femoral artery blood flow (ultrasound Doppler) were evaluated during incremental one-leg knee-extension exercise (reduced constraints to cardiovascular O2 delivery) carried out to voluntary exhaustion in a normoxic environment. Mitochondrial respiration was evaluated ex vivo by high-resolution respirometry in permeabilized vastus lateralis fibres. V̇O2peak decreased (P < 0.05) after N-BR (0.98 ± 0.13 L min-1 ) and H-BR (0.96 ± 0.17 L min-1 ) vs. BDC (1.05 ± 0.14 L min-1 ). In the presence of a decreased (by ∼6-8%) thigh muscle volume, V̇O2peak normalized per unit of muscle mass was not affected by both interventions. Δ[deoxy(Hb + Mb)]peak decreased (P < 0.05) after N-BR (65 ± 13% of limb ischaemia) and H-BR (62 ± 12%) vs. BDC (73 ± 13%). H-AMB did not alter V̇O2peak or Δ[deoxy(Hb + Mb)]peak . An overshoot of Δ[deoxy(Hb + Mb)] was evident during the first minute of unloaded exercise after N-BR and H-BR. Arterial blood flow to the lower limb during both unloaded and peak knee extension was not affected by any intervention. Maximal ADP-stimulated mitochondrial respiration decreased (P < 0.05) after all interventions vs. control. In 21 day N-BR, a significant impairment of oxidative metabolism occurred downstream of cardiovascular O2 delivery, affecting both mitochondrial respiration and presumably the intramuscular matching between O2 supply and utilization. Superposition of H on BR did not worsen the impairment induced by BR alone.
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Affiliation(s)
- Desy Salvadego
- Department of Medicine, University of Udine, Udine, Italy
| | - Michail E Keramidas
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Stockholm, Sweden
| | - Roger Kölegård
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Stockholm, Sweden
| | - Lorenza Brocca
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Stefano Lazzer
- Department of Medicine, University of Udine, Udine, Italy
| | - Irene Mavelli
- Department of Medicine, University of Udine, Udine, Italy
| | - Jörn Rittweger
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany.,Department of Pediatrics and Adolescent Medicine, Medical Faculty, University of Cologne, Cologne, Germany
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Centre, Royal Institute of Technology, Stockholm, Sweden
| | - Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia.,Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Bruno Grassi
- Department of Medicine, University of Udine, Udine, Italy.,Institute of Bioimaging and Molecular Physiology, National Research Council, Milano, Italy
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11
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Mille-Hamard L, Breuneval C, Rousseau AS, Grimaldi P, Billat VL. Transcriptional modulation of mitochondria biogenesis pathway at and above critical speed in mice. Mol Cell Biochem 2015; 405:223-32. [DOI: 10.1007/s11010-015-2413-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 04/18/2015] [Indexed: 01/08/2023]
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12
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Cannavino J, Brocca L, Sandri M, Grassi B, Bottinelli R, Pellegrino MA. The role of alterations in mitochondrial dynamics and PGC-1α over-expression in fast muscle atrophy following hindlimb unloading. J Physiol 2015; 593:1981-95. [PMID: 25565653 DOI: 10.1113/jphysiol.2014.286740] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/01/2015] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Skeletal muscle atrophy occurs as a result of disuse. Although several studies have established that a decrease in protein synthesis and increase in protein degradation lead to muscle atrophy, little is known about the triggers underlying such processes. A growing body of evidence challenges oxidative stress as a trigger of disuse atrophy; furthermore, it is also becoming evident that mitochondrial dysfunction may play a causative role in determining muscle atrophy. Mitochondrial fusion and fission have emerged as important processes that govern mitochondrial function and PGC-1α may regulate fusion/fission events. Although most studies on mice have focused on the anti-gravitary slow soleus muscle as it is preferentially affected by disuse atrophy, several fast muscles (including gastrocnemius) go through a significant loss of mass following unloading. Here we found that in fast muscles an early down-regulation of pro-fusion proteins, through concomitant AMP-activated protein kinase (AMPK) activation, can activate catabolic systems, and ultimately cause muscle mass loss in disuse. Elevated muscle PGC-1α completely preserves muscle mass by preventing the fall in pro-fusion protein expression, AMPK and catabolic system activation, suggesting that compounds inducing PGC-1α expression could be useful to treat and prevent muscle atrophy. ABSTRACT The mechanisms triggering disuse muscle atrophy remain of debate. It is becoming evident that mitochondrial dysfunction may regulate pathways controlling muscle mass. We have recently shown that mitochondrial dysfunction plays a major role in disuse atrophy of soleus, a slow, oxidative muscle. Here we tested the hypothesis that hindlimb unloading-induced atrophy could be due to mitochondrial dysfunction in fast muscles too, notwithstanding their much lower mitochondrial content. Gastrocnemius displayed atrophy following both 3 and 7 days of unloading. SOD1 and catalase up-regulation, no H2 O2 accumulation and no increase of protein carbonylation suggest the antioxidant defence system efficiently reacted to redox imbalance in the early phases of disuse. A defective mitochondrial fusion (Mfn1, Mfn2 and OPA1 down-regulation) occurred together with an impairment of OXPHOS capacity. Furthermore, at 3 days of unloading higher acetyl-CoA carboxylase (ACC) phosphorylation was found, suggesting AMP-activated protein kinase (AMPK) pathway activation. To test the role of mitochondrial alterations we used Tg-mice overexpressing PGC-1α because of the known effect of PGC-1α on stimulation of Mfn2 expression. PGC-α overexpression was sufficient to prevent (i) the decrease of pro-fusion proteins (Mfn1, Mfn2 and OPA1), (ii) activation of the AMPK pathway, (iii) the inducible expression of MuRF1 and atrogin1 and of authopagic factors, and (iv) any muscle mass loss in response to disuse. As the effects of increased PGC-1α activity were sustained throughout disuse, compounds inducing PGC-1α expression could be useful to treat and prevent muscle atrophy also in fast muscles.
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Affiliation(s)
- Jessica Cannavino
- Department of Molecular Medicine, University of Pavia, 27100, Pavia, Italy
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13
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Cannavino J, Brocca L, Sandri M, Bottinelli R, Pellegrino MA. PGC1-α over-expression prevents metabolic alterations and soleus muscle atrophy in hindlimb unloaded mice. J Physiol 2014; 592:4575-89. [PMID: 25128574 DOI: 10.1113/jphysiol.2014.275545] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Prolonged skeletal muscle inactivity causes muscle fibre atrophy. Redox imbalance has been considered one of the major triggers of skeletal muscle disuse atrophy, but whether redox imbalance is actually the major cause or simply a consequence of muscle disuse remains of debate. Here we hypothesized that a metabolic stress mediated by PGC-1α down-regulation plays a major role in disuse atrophy. First we studied the adaptations of soleus to mice hindlimb unloading (HU) in the early phase of disuse (3 and 7 days of HU) with and without antioxidant treatment (trolox). HU caused a reduction in cross-sectional area, redox status alteration (NRF2, SOD1 and catalase up-regulation), and induction of the ubiquitin proteasome system (MuRF-1 and atrogin-1 mRNA up-regulation) and autophagy (Beclin1 and p62 mRNA up-regulation). Trolox completely prevented the induction of NRF2, SOD1 and catalase mRNAs, but not atrophy or induction of catabolic systems in unloaded muscles, suggesting that oxidative stress is not a major cause of disuse atrophy. HU mice showed a marked alteration of oxidative metabolism. PGC-1α and mitochondrial complexes were down-regulated and DRP1 was up-regulated. To define the link between mitochondrial dysfunction and disuse muscle atrophy we unloaded mice overexpressing PGC-1α. Transgenic PGC-1α animals did not show metabolic alteration during unloading, preserving muscle size through the reduction of autophagy and proteasome degradation. Our results indicate that mitochondrial dysfunction plays a major role in disuse atrophy and that compounds inducing PGC-1α expression could be useful to treat/prevent muscle atrophy.
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Affiliation(s)
- Jessica Cannavino
- Department of Molecular Medicine, University of Pavia, 27100, Pavia, Italy
| | - Lorenza Brocca
- Department of Molecular Medicine, University of Pavia, 27100, Pavia, Italy
| | - Marco Sandri
- Venetian Institute of Molecular Medicine and Dulbecco Telethon Institute, 35129, Padova, Italy Interuniversity Institute of Myology, University of Pavia, Pavia, Italy
| | - Roberto Bottinelli
- Department of Molecular Medicine, University of Pavia, 27100, Pavia, Italy Fondazione Salvatore Maugeri (IRCCS), Scientific Institute of Pavia, Pavia, Italy Interdipartimental Centre for Biology and Sport Medicine, University of Pavia, Pavia, Italy
| | - Maria Antonietta Pellegrino
- Department of Molecular Medicine, University of Pavia, 27100, Pavia, Italy Interuniversity Institute of Myology, University of Pavia, Pavia, Italy Interdipartimental Centre for Biology and Sport Medicine, University of Pavia, Pavia, Italy
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Remels AHV, Pansters NA, Gosker HR, Schols AMWJ, Langen RCJ. Activation of alternative NF-κB signaling during recovery of disuse-induced loss of muscle oxidative phenotype. Am J Physiol Endocrinol Metab 2014; 306:E615-26. [PMID: 24425759 DOI: 10.1152/ajpendo.00452.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Physical inactivity-induced loss of skeletal muscle oxidative phenotype (OXPHEN), often observed in chronic disease, adversely affects physical functioning and quality of life. Potential therapeutic targets remain to be identified, since the molecular mechanisms involved in reloading-induced recovery of muscle OXPHEN remain incompletely understood. We hypothesized a role for alternative NF-κB, as a recently identified positive regulator of muscle OXPHEN, in reloading-induced alterations in muscle OXPHEN. Markers and regulators (including alternative NF-κB signaling) of muscle OXPHEN were investigated in gastrocnemius muscle of mice subjected to a hindlimb suspension/reloading (HLS/RL) protocol. Expression levels of oxidative phosphorylation subunits and slow myosin heavy chain isoforms I and IIA increased rapidly upon RL. After an initial decrease upon HLS, mRNA levels of peroxisome proliferator-activated receptor (PPAR)-γ coactivator (PGC) molecules PGC-1α and PGC-1β and mRNA levels of mitochondrial transcription factor A (Tfam) and estrogen-related receptor α increased upon RL. PPAR-δ, nuclear respiratory factor 1 (NRF-1), NRF-2α, and sirtuin 1 mRNA levels increased during RL although expression levels were unaltered upon HLS. In addition, both Tfam and NRF-1 protein levels increased significantly during the RL period. Moreover, upon RL, IKK-α mRNA and protein levels increased, and phosphorylation of P100 and subsequent processing to P52 were elevated, reflecting alternative NF-κB activation. We conclude that RL-induced recovery of muscle OXPHEN is associated with activation of alternative NF-κB signaling.
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Affiliation(s)
- A H V Remels
- NUTRIM School for Nutrition, Toxicology, and Metabolism, Department of Respiratory Medicine, Maastricht University Medical Center +, Maastricht, The Netherlands
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15
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Increased insulin sensitivity and distorted mitochondrial adaptations during muscle unloading. Int J Mol Sci 2012; 13:16971-85. [PMID: 23443131 PMCID: PMC3546734 DOI: 10.3390/ijms131216971] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2012] [Revised: 11/27/2012] [Accepted: 11/29/2012] [Indexed: 11/17/2022] Open
Abstract
We aimed to further investigate mitochondrial adaptations to muscle disuse and the consequent metabolic disorders. Male rats were submitted to hindlimb unloading (HU) for three weeks. Interestingly, HU increased insulin sensitivity index (ISI) and decreased blood level of triglyceride and insulin. In skeletal muscle, HU decreased expression of pyruvate dehydrogenase kinase 4 (PDK4) and its protein level in mitochondria. HU decreased mtDNA content and mitochondrial biogenesis biomarkers. Dynamin-related protein (Drp1) in mitochondria and Mfn2 mRNA level were decreased significantly by HU. Our findings provide more extensive insight into mitochondrial adaptations to muscle disuse, involving the shift of fuel utilization towards glucose, the decreased mitochondrial biogenesis and the distorted mitochondrial dynamics.
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16
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Lionikas A, Meharg C, Derry JM, Ratkevicius A, Carroll AM, Vandenbergh DJ, Blizard DA. Resolving candidate genes of mouse skeletal muscle QTL via RNA-Seq and expression network analyses. BMC Genomics 2012; 13:592. [PMID: 23126637 PMCID: PMC3505184 DOI: 10.1186/1471-2164-13-592] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 10/26/2012] [Indexed: 11/28/2022] Open
Abstract
Background We have recently identified a number of Quantitative Trait Loci (QTL) contributing to the 2-fold muscle weight difference between the LG/J and SM/J mouse strains and refined their confidence intervals. To facilitate nomination of the candidate genes responsible for these differences we examined the transcriptome of the tibialis anterior (TA) muscle of each strain by RNA-Seq. Results 13,726 genes were expressed in mouse skeletal muscle. Intersection of a set of 1061 differentially expressed transcripts with a mouse muscle Bayesian Network identified a coherent set of differentially expressed genes that we term the LG/J and SM/J Regulatory Network (LSRN). The integration of the QTL, transcriptome and the network analyses identified eight key drivers of the LSRN (Kdr, Plbd1, Mgp, Fah, Prss23, 2310014F06Rik, Grtp1, Stk10) residing within five QTL regions, which were either polymorphic or differentially expressed between the two strains and are strong candidates for quantitative trait genes (QTGs) underlying muscle mass. The insight gained from network analysis including the ability to make testable predictions is illustrated by annotating the LSRN with knowledge-based signatures and showing that the SM/J state of the network corresponds to a more oxidative state. We validated this prediction by NADH tetrazolium reductase staining in the TA muscle revealing higher oxidative potential of the SM/J compared to the LG/J strain (p<0.03). Conclusion Thus, integration of fine resolution QTL mapping, RNA-Seq transcriptome information and mouse muscle Bayesian Network analysis provides a novel and unbiased strategy for nomination of muscle QTGs.
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Affiliation(s)
- Arimantas Lionikas
- School of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, UK.
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17
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Liu J, Peng Y, Cui Z, Wu Z, Qian A, Shang P, Qu L, Li Y, Liu J, Long J. Depressed mitochondrial biogenesis and dynamic remodeling in mouse tibialis anterior and gastrocnemius induced by 4-week hindlimb unloading. IUBMB Life 2012; 64:901-10. [PMID: 23024034 DOI: 10.1002/iub.1087] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Accepted: 08/09/2012] [Indexed: 12/13/2022]
Abstract
Mitochondrial dynamics is highly involved in muscle atrophy, the slow twitch muscle as soleus, preferentially affected by hindlimb unloading (HU), was well characterized by mitochondrial dysfunction in biogenesis. However, the fast twitch muscles like tibialis anterior (TA) and gastrocnemius (GAS), which are the most massive parts of the hindlimb muscles, are less elucidated on mitochondrial adaptations responding to HU. To investigate the mitochondrial dynamic responses and the involved molecules mediating atrophy in TA and GAS, we studied a 4-week HU mouse model. We found GAS was preferentially affected to atrophy by unloading compared with TA. Furthermore, the depressed mitochondrial biogenesis occurred, accounting for mitochondrial loss in GAS by unloading. PGC-1α, as well as its transcriptional/post-translational modification regulators, such as p-CREB, SIRT1, and p-AMPK, were consistently reduced in response to unloading in GAS. Molecules relevant to autophagy, mitochondrial fusion, and fission, were compromised following unloading both in TA and GAS. These results suggested that TA exhibited resistance to unloading induced muscle atrophy while GAS presented significant mitochondrial loss, which might be due to the mitochondrial biogenesis suppressed by the inactivation of PGC-1α. However, both in TA and GAS muscles, a similar sedentary mitochondrial dynamics of mitochondrial fusion and fission was induced by unloading though TA exhibited little muscle atrophy.
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Affiliation(s)
- Jing Liu
- Institute of Mitochondrial Biology and Medicine, The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Xi'an Jiaotong University School of Life Science and Technology, Xi'an 710049, China
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18
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Mazzatti D, Lim FL, O'Hara A, Wood IS, Trayhurn P. A microarray analysis of the hypoxia-induced modulation of gene expression in human adipocytes. Arch Physiol Biochem 2012; 118:112-20. [PMID: 22352407 DOI: 10.3109/13813455.2012.654611] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The effect of hypoxia on global gene expression in human adipocytes has been examined using DNA microarrays. Adipocytes (Zen-Bio, day 12 post-differentiation) were exposed to hypoxia (1% O(2)) or 'normoxia' (21% O(2)) for 24 h and extracted RNA probed with Agilent arrays containing 41,152 probes. A total of 1346 probes were differentially expressed (>2.0-fold change, P < 0.01) in response to hypoxia; 650 genes were up-regulated (including LEP, IL6, VEGF, ANGPTL4) and 650 down-regulated (including ADIPOQ, UCP2). Major genes not previously identified as hypoxia-sensitive in adipocytes include AQP3, FABP3, FABP5 and PPARGC1A. Ingenuity analysis indicated that several pathways and functions were modulated by hypoxia, including glucose utilization, lipid oxidation and cell death. Network analysis indicated a down-regulation of p38/MAPK and PGC-1α signalling in the adipocytes. It is concluded that hypoxia has extensive effects on human adipocyte gene expression, consistent with low O(2) tension underlying adipose tissue dysfunction in obesity.
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Affiliation(s)
- Dawn Mazzatti
- Unilever R&D Discover, Colworth Park, Bedfordshire MK44 1LQ, United Kingdom
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19
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O'Hara A, Lim FL, Mazzatti DJ, Trayhurn P. Stimulation of inflammatory gene expression in human preadipocytes by macrophage-conditioned medium: upregulation of IL-6 production by macrophage-derived IL-1β. Mol Cell Endocrinol 2012; 349:239-47. [PMID: 22079434 DOI: 10.1016/j.mce.2011.10.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2011] [Revised: 10/07/2011] [Accepted: 10/26/2011] [Indexed: 11/29/2022]
Abstract
The aim of this study was to examine the effects of macrophage secretions on global gene expression in human preadipocytes using microarrays. Preadipocytes were cultured with unconditioned or conditioned medium from U937 macrophages, and gene expression examined with Agilent arrays (43,000 probes). 472 transcripts were differentially regulated (>2-fold difference; P<0.05) between preadipocytes in the conditioned medium compared to the unconditioned; 401 were upregulated and 71 downregulated. The upregulated transcripts were particularly linked to inflammation, including IL-1β, IL-6, and CCL20 (16.8-, 10.0-, and 8.9-fold increases, respectively) together with matrix metalloproteinases (MMP3, MMP9 and MMP12). Major pathways regulated by the conditioned medium were linked to inflammation, macrophage infiltration and lipid accumulation. Network analysis identified NFkB and IL-1β as central nodes in the upregulation of multiple inflammation-related genes. Treatment with an IL-1β neutralising antibody abolished the stimulation of IL-6 secretion by conditioned medium, indicating that IL-1β is a key regulator of preadipocyte IL-6 production. Macrophages evoke extensive changes in preadipocyte gene expression.
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Affiliation(s)
- Adrian O'Hara
- Obesity Biology Research Unit, School of Clinical Sciences, University of Liverpool, Liverpool L69 3GA, UK
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20
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Dhahbi JM, Atamna H, Boffelli D, Martin DIK, Spindler SR. mRNA-Seq reveals complex patterns of gene regulation and expression in the mouse skeletal muscle transcriptome associated with calorie restriction. Physiol Genomics 2012; 44:331-44. [PMID: 22274562 DOI: 10.1152/physiolgenomics.00129.2011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Sarcopenia is an age-associated loss of skeletal muscle mass and strength that increases the risk of disability. Calorie restriction (CR), the consumption of fewer calories while maintaining adequate nutrition, mitigates sarcopenia and many other age-related diseases. To identify potential mechanisms by which CR preserves skeletal muscle integrity during aging, we used mRNA-Seq for deep characterization of gene regulation and mRNA abundance in skeletal muscle of old mice compared with old mice subjected to CR. mRNA-Seq revealed complex CR-associated changes in expression of mRNA isoforms, many of which occur without a change in total message abundance and thus would not be detected by methods other than mRNA-Seq. Functional annotation of differentially expressed genes reveals CR-associated upregulation of pathways involved in energy metabolism and lipid biosynthesis, and downregulation of pathways mediating protein breakdown and oxidative stress, consistent with earlier microarray-based studies. CR-associated changes not noted in previous studies involved downregulation of genes controlling actin cytoskeletal structures and muscle development. These CR-associated changes reflect generally healthier muscle, consistent with CR's mitigation of sarcopenia. mRNA-Seq generates a rich picture of the changes in gene expression associated with CR, and may facilitate identification of genes that are primary mediators of CR's effects.
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Affiliation(s)
- Joseph M Dhahbi
- Department of Biochemistry, University of California at Riverside, 92521, USA.
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21
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Hutchins-Wiese HL, Li Y, Hannon K, Watkins BA. Hind limb suspension and long-chain omega-3 PUFA increase mRNA endocannabinoid system levels in skeletal muscle. J Nutr Biochem 2011; 23:986-93. [PMID: 22051448 DOI: 10.1016/j.jnutbio.2011.05.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 04/18/2011] [Accepted: 05/13/2011] [Indexed: 11/28/2022]
Abstract
Muscle disuse has numerous physiological consequences that end up with significant catabolic metabolism and ultimately tissue atrophy. What is not known is how muscle atrophy affects the endocannabinoid (EC) system. Arachidonic acid (AA) is the substrate for anandamide (AEA) and 2-arachidonylgycerol (2-AG), which act as agonists for cannabinoid receptors CB1 and CB2 found in muscle. Diets with n-3 polyunsaturated fatty acids (PUFA) have been shown to reduce tissue levels of AA, AEA and 2-AG. Therefore, we hypothesized that hind limb suspension (HS)-induced muscle atrophy and intake of n-3 PUFA will change mRNA levels of the EC system. Mice were randomized and assigned to a moderate n-3 PUFA [11.7 g/kg eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA)], high n-3 PUFA (17.6 g/kg EPA+DHA) or control diets for 12 days and then subjected to HS or continued weight bearing (WB) for 14 days. HS resulted in body weight, epididymal fat pad and quadriceps muscle loss compared to WB. Compared to WB, HS had greater mRNA levels of AEA and 2-AG synthesis enzymes and CB2 in the atrophied quadriceps muscle. The high n-3 PUFA diet resulted in greater mRNA levels of EC synthesis enzymes, and CB1 and CB2. The higher mRNA levels for EC with HS and dietary n-3 PUFA suggest that muscle disuse and diet induce changes in the EC system to sensitize muscle in response to metabolic and physiological consequences of atrophy.
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Giangreco A, Lu L, Mazzatti DJ, Spencer-Dene B, Nye E, Teixeira VH, Janes SM. Myd88 deficiency influences murine tracheal epithelial metaplasia and submucosal gland abundance. J Pathol 2011; 224:190-202. [PMID: 21557220 PMCID: PMC3434371 DOI: 10.1002/path.2876] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Tracheal epithelial remodelling, excess mucus production, and submucosal gland hyperplasia are features of numerous lung diseases, yet their origins remain poorly understood. Previous studies have suggested that NF-κB signalling may regulate airway epithelial homeostasis. The purpose of this study was to determine whether deletion of the NF-κB signalling pathway protein myeloid differentiation factor 88 (Myd88) influenced tracheal epithelial cell phenotype. We compared wild-type and Myd88-deficient or pharmacologically inhibited adult mouse tracheas and determined that in vivo Myd88 deletion resulted in increased submucosal gland number, secretory cell metaplasia, and excess mucus cell abundance. We also found that Myd88 was required for normal resolution after acute tracheal epithelial injury. Microarray analysis revealed that uninjured Myd88-deficient tracheas contained 103 transcripts that were differentially expressed relative to wild-type and all injured whole tracheal samples. These clustered into several ontologies and networks that are known to functionally influence epithelial cell phenotype. Comparing these transcripts to those expressed in airway progenitor cells revealed only five common genes, suggesting that Myd88 influences tracheal epithelial homeostasis through an extrinsic mechanism. Overall, this study represents the first identification of Myd88 as a regulator of adult tracheal epithelial cell phenotype. Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
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Affiliation(s)
- Adam Giangreco
- Centre for Respiratory Research, University College London, Rayne Institute, 5 University Street, London WC1E 6JF, UK.
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Vitošević B, Ranković G, Popović-Ilić T. ROLE OF PPAR-* IN DETERMINATION OF MUSCLE FIBER TYPE IN RESPONSE TO EXERCISE. ACTA MEDICA MEDIANAE 2011. [DOI: 10.5633/amm.2011.0211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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The effects of simulated microgravity on skeletal muscle of Japanese quail: transmission electron microscopic study. ACTA VET BRNO 2011. [DOI: 10.2754/avb201180010119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aim of the present study was to investigate the effects of simulated microgravity (hypodynamia) on the structure of the skeletal muscle (m. gastrocnemius) in developing Japanese quail by transmission electron microscopy. Samples of muscle tissues from experimental (n = 28) and control (n = 28) birds were collected at day 7, 14, 28, 42 and 56 of age. The structure of m. gastrocnenmius was changed depending on hypodynamia length. The first extensive structural changes were found on day 14 of age. The mitochondria were enlarged and the spaces between the myofibrils were slightly extended compared to control. The sarcomeres were irregular and lipid droplets occurred in the sarcoplasm. Further developmental changes occurred on day 28 of age. Mitochondria fused into the giant mitochondria which frequently exceeded the length of one sarcomere. Moreover, at 42 days of age, beside the above mentioned changes, sarcoplasmic reticulum was dilated and the number of mitochondrial cristae was reduced. However, the structure of m. gastrocnemius on day 56 was less damaged compared to the damage observed on day 42 of age. Presented results indicate that the continuous stay of male Japanese quail under simulated microgravity has a negative impact on the structure of m. gastrocnemius, but also the ability of muscle tissue to cope with these specific conditions.
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Wagatsuma A, Kotake N, Kawachi T, Shiozuka M, Yamada S, Matsuda R. Mitochondrial adaptations in skeletal muscle to hindlimb unloading. Mol Cell Biochem 2011; 350:1-11. [PMID: 21165677 DOI: 10.1007/s11010-010-0677-1] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Accepted: 12/02/2010] [Indexed: 12/20/2022]
Abstract
To gain insight into the regulation of mitochondrial adaptations to hindlimb unloading (HU), the activity of mitochondrial enzymes and the expression of nuclear-encoded genes which control mitochondrial properties in mouse gastrocnemius muscle were investigated. Biochemical and enzyme histochemical analysis showed that subsarcolemmal mitochondria were lost largely than intermyofibrillar mitochondria after HU. Gene expression analysis revealed disturbed or diminished gene expression patterns. The three main results of this analysis are as follows. First, in contrast to peroxisome proliferator-activated receptor γ coactivator 1 β (PGC-1β) and PGC-1-related coactivator, which were down-regulated by HU, PGC-1α was up-regulated concomitant with decreased expression of its DNA binding transcription factors, PPARα, and estrogen-related receptor α (ERRα). Moreover, there was no alteration in expression of nuclear respiratory factor 1, but its downstream target gene, mitochondrial transcription factor A, was down-regulated. Second, both mitofusin 2 and fission 1, which control mitochondrial morphology, were down-regulated. Third, ATP-dependent Lon protease, which participates in mitochondrial-protein degradation, was also down-regulated. These findings suggest that HU may induce uncoordinated expression of PGC-1 family coactivators and DNA binding transcription factors, resulting in reducing ability of mitochondrial biogenesis. Furthermore, down-regulation of mitochondrial morphology-related genes associated with HU may be also involved in alterations in intracellular mitochondrial distribution.
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MESH Headings
- Adaptation, Physiological/genetics
- Adaptation, Physiological/physiology
- Animals
- Citrate (si)-Synthase/genetics
- Citrate (si)-Synthase/metabolism
- Female
- Gene Expression Regulation
- Gene Expression Regulation, Enzymologic
- Hindlimb Suspension/physiology
- Mice
- Mitochondria, Muscle/genetics
- Mitochondria, Muscle/metabolism
- Mitochondria, Muscle/physiology
- Muscle Proteins/genetics
- Muscle Proteins/metabolism
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/physiology
- PPAR gamma/genetics
- PPAR gamma/metabolism
- Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha
- Receptors, Estrogen/genetics
- Receptors, Estrogen/metabolism
- SKP Cullin F-Box Protein Ligases/genetics
- SKP Cullin F-Box Protein Ligases/metabolism
- Succinate Dehydrogenase/genetics
- Succinate Dehydrogenase/metabolism
- Trans-Activators/genetics
- Trans-Activators/metabolism
- Transcription Factors
- ERRalpha Estrogen-Related Receptor
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Affiliation(s)
- Akira Wagatsuma
- Department of Life Sciences, The University of Tokyo, Meguro-ku, Tokyo, Japan.
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Thompson D, Markovitch D, Betts JA, Mazzatti D, Turner J, Tyrrell RM. Time course of changes in inflammatory markers during a 6-mo exercise intervention in sedentary middle-aged men: a randomized-controlled trial. J Appl Physiol (1985) 2010; 108:769-79. [PMID: 20368384 DOI: 10.1152/japplphysiol.00822.2009] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Regular exercise may improve systemic markers of chronic inflammation, but direct evidence and dose-response information is lacking. The objective of this study was to examine the effect and time course of changes in markers of chronic inflammation in response to progressive exercise training (and subsequent detraining). Forty-one sedentary men 45-64 yr of age completed either a progressive 24-wk exercise intervention or control followed by short-term removal of the intervention (2-wk detraining). Serum IL-6 fell by -0.4 pg/ml (SD 0.6) after 12 wk and responded to moderate-intensity exercise. Serum alanine aminotransferase (ALT) activity fell -7 U/l (SD 11) at 24 wk although there was no evidence of any change by week 12 (and therefore ALT required more vigorous-intensity activity and/or a more prolonged intervention). The effect on IL-6 was lost after 2-wk detraining whereas the change in ALT was retained. The temporal fall and rise in IL-6 with training and subsequent detraining in men with high IL-6 at baseline provided a retrospective opportunity to examine parallel genomic changes in peripheral mononuclear cells. A subset of 53 probes was differentially regulated by at least twofold after training with 31 of these changes being lost after detraining (n = 6). IL-6 responded quickly to the carefully monitored exercise intervention (within weeks) and required only moderate-intensity exercise, whereas ALT took longer to change and/or required more vigorous-intensity exercise. Further work is required to determine whether any of the genes that temporally changed in parallel with changes in IL-6 are a cause or consequence of this response.
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Affiliation(s)
- Dylan Thompson
- School for Health, University of Bath, Bath, United Kingdom.
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Andrianjafiniony T, Dupré-Aucouturier S, Letexier D, Couchoux H, Desplanches D. Oxidative stress, apoptosis, and proteolysis in skeletal muscle repair after unloading. Am J Physiol Cell Physiol 2010; 299:C307-15. [DOI: 10.1152/ajpcell.00069.2010] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Although several lines of evidence link muscle-derived oxidants and inflammation to skeletal muscle wasting via regulation of apoptosis and proteolysis, little information is currently available on muscle repair. The present work was designed to study oxidative stress response, inflammatory cytokines, apoptotic, or proteolytic pathways during the early (1 and 5 days) and later (14 days) stages of the regrowth process subsequent to 14 days of hindlimb unloading. During the early stages of reloading, muscle mass recovery ( day 5) was facilitated by transcriptional downregulation ( day 1) of pathways involved in muscle proteolysis [μ-calpain, atrogin-1/muscle atrophy F-box (MAFbx), and muscle RING finger-1/(MuRF1) mRNA] and upregulation of an autophagy-related protein Beclin-1 ( day 5). At the same time, oxidative stress (glutathione vs. glutathione disulfide ratio, superoxide dismutase, catalase activities) remained still enhanced, whereas the increased uncoupling protein 3 gene expression recovered. Increased caspase-9 (mitochondrial-driven apoptosis) and decreased caspase-12 (sarcoplasmic reticulum-mediated apoptosis) activation was also normalized at early stages ( day 5). Conversely, the receptor-mediated apoptotic pathway initiated by ligand-induced (tumor necrosis factor-α, TNF-α) binding and promoting the activation of caspase-8 remained elevated until 14 days. Our data suggest that at early stages, muscle repair is mediated via the modulation of mitochondrial-driven apoptosis and muscle proteolysis. Despite full muscle mass recovery, oxidative stress and TNF-α-mediated apoptotic pathway are still activated till later stages of muscle remodeling.
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Affiliation(s)
- Tina Andrianjafiniony
- Université de Lyon, Lyon; and Centre National de la Recherche Scientifique, UMR 5123, Laboratoire de Physiologie Intégrative, Cellulaire et Moléculaire Université Lyon 1, Villeurbanne Cedex, France
| | - Sylvie Dupré-Aucouturier
- Université de Lyon, Lyon; and Centre National de la Recherche Scientifique, UMR 5123, Laboratoire de Physiologie Intégrative, Cellulaire et Moléculaire Université Lyon 1, Villeurbanne Cedex, France
| | - Dominique Letexier
- Université de Lyon, Lyon; and Centre National de la Recherche Scientifique, UMR 5123, Laboratoire de Physiologie Intégrative, Cellulaire et Moléculaire Université Lyon 1, Villeurbanne Cedex, France
| | - Harold Couchoux
- Université de Lyon, Lyon; and Centre National de la Recherche Scientifique, UMR 5123, Laboratoire de Physiologie Intégrative, Cellulaire et Moléculaire Université Lyon 1, Villeurbanne Cedex, France
| | - Dominique Desplanches
- Université de Lyon, Lyon; and Centre National de la Recherche Scientifique, UMR 5123, Laboratoire de Physiologie Intégrative, Cellulaire et Moléculaire Université Lyon 1, Villeurbanne Cedex, France
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Mazzucco S, Agostini F, Mangogna A, Cattin L, Biolo G. Prolonged inactivity up-regulates cholesteryl ester transfer protein independently of body fat changes in humans. J Clin Endocrinol Metab 2010; 95:2508-12. [PMID: 20228163 DOI: 10.1210/jc.2009-2561] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
CONTEXT Physical inactivity is associated with insulin resistance and decreased high-density lipoprotein (HDL) cholesterol. Cholesteryl ester transfer protein (CETP) is involved in cholesterol metabolism, being responsible for the transfer of cholesteryl esters from HDL to very low- and low-density lipoproteins. OBJECTIVE We hypothesized that physical inactivity could decrease HDL cholesterol through changes in CETP availability. DESIGN AND PARTICIPANTS Twenty-four healthy, male volunteers (aged 23.1 +/- 0.5 yr) were investigated in eucaloric conditions before and at the end of 35 d of experimental bed rest. MEASURES Changes in body composition were monitored by bioimpedance throughout the study. Before and at the end of the experimental period, plasma insulin and glucose and plasma lipid pattern as well as CETP concentrations were determined. RESULTS Our results demonstrated that during bed rest, fat mass did not change significantly, whereas fat-free mass decreased by 3.9 +/- 0.4% (P < 0.01). The homeostatic model assessment index of insulin resistance significantly (P < 0.001) increased by 47 +/- 11% after bed rest. Bed rest decreased HDL cholesterol by 12 +/- 3% (P < 0.05), increased triglycerides by 51 +/- 10% (P < 0.05), whereas it did not change significantly low-density lipoprotein cholesterol. Plasma CETP concentration increased after bed rest by 27 +/- 9% (P < 0.01). Bed rest-induced changes in CETP concentrations inversely correlated with changes in the ratio between HDL and non-HDL cholesterol (n = 24; R = -0.43; P < 0.05). CONCLUSIONS Physical inactivity decreases HDL cholesterol, at least in part, through CETP up-regulation.
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Affiliation(s)
- Sara Mazzucco
- Department of Medical, Technological, and Translational Science, Division of Internal Medicine, University of Trieste, 34139 Trieste, Italy
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Ehrenborg E, Krook A. Regulation of skeletal muscle physiology and metabolism by peroxisome proliferator-activated receptor delta. Pharmacol Rev 2010; 61:373-93. [PMID: 19805479 DOI: 10.1124/pr.109.001560] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Agonists directed against the alpha and gamma isoforms of the peroxisome proliferator-activated receptors (PPARs) have become important for the respective treatment of hypertriglyceridemia and insulin resistance associated with metabolic disease. PPARdelta is the least well characterized of the three PPAR isoforms. Skeletal muscle insulin resistance is a primary risk factor for the development of type 2 diabetes. There is increasing evidence that PPARdelta is an important regulator of skeletal muscle metabolism, in particular, muscle lipid oxidation, highlighting the potential utility of this isoform as a drug target. In addition, PPARdelta seems to be a key regulator of skeletal muscle fiber type and a possible mediator of the adaptations noted in skeletal muscle in response to exercise. In this review we summarize the current status regarding the regulation, and the metabolic effects, of PPARdelta in skeletal muscle.
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Affiliation(s)
- Ewa Ehrenborg
- Atherosclerosis Research Unit, Department of Medicine, Center for Molecular Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden
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Brocca L, Pellegrino MA, Desaphy JF, Pierno S, Camerino DC, Bottinelli R. Is oxidative stress a cause or consequence of disuse muscle atrophy in mice? A proteomic approach in hindlimb-unloaded mice. Exp Physiol 2009; 95:331-50. [PMID: 19819934 DOI: 10.1113/expphysiol.2009.050245] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Two-dimensional proteomic maps of soleus (Sol), a slow oxidative muscle, and gastrocnemius (Gas), a fast glycolytic muscle of control mice (CTRL), of mice hindlimb unloaded for 14 days (HU mice) and of HU mice treated with trolox (HU-TRO), a selective and potent antioxidant, were compared. The proteomic analysis identified a large number of differentially expressed proteins in a pool of approximately 800 proteins in both muscles. The protein pattern of Sol and Gas adapted very differently to hindlimb unloading. The most interesting adaptations related to the cellular defense systems against oxidative stress and energy metabolism. In HU Sol, the antioxidant defense systems and heat shock proteins were downregulated, and protein oxidation index and lipid peroxidation were higher compared with CTRL Sol. In contrast, in HU Gas the antioxidant defense systems were upregulated, and protein oxidation index and lipid peroxidation were normal. Notably, both Sol and Gas muscles and their muscle fibres were atrophic. Antioxidant administration prevented the impairment of the antioxidant defense systems in Sol and further enhanced them in Gas. Accordingly, it restored normal levels of protein oxidation and lipid peroxidation in Sol. However, muscle and muscle fibre atrophy was not prevented either in Sol or in Gas. A general downsizing of all energy production systems in Sol and a shift towards glycolytic metabolism in Gas were observed. Trolox administration did not prevent metabolic adaptations in either Sol or Gas. The present findings suggest that oxidative stress is not a major determinant of muscle atrophy in HU mice.
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Affiliation(s)
- Lorenza Brocca
- Department of Physiology, Human Physiology Unit, University of Pavia, Via Forlanini 6, 27100 Pavia, Italy
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Microarray analysis identifies matrix metalloproteinases (MMPs) as key genes whose expression is up-regulated in human adipocytes by macrophage-conditioned medium. Pflugers Arch 2009; 458:1103-14. [PMID: 19585142 DOI: 10.1007/s00424-009-0693-8] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2009] [Revised: 06/03/2009] [Accepted: 06/18/2009] [Indexed: 02/01/2023]
Abstract
White adipose tissue exhibits inflammation as tissue mass expands in obesity, involving macrophage infiltration and a direct inflammatory response by adipocytes. DNA microarrays and conditioned medium have been used to examine the effects of macrophages on global gene expression in human adipocytes. SGBS adipocytes, differentiated in culture, were treated with macrophage-conditioned medium (U937 cells) for 4 or 24 h; control cells received unconditioned medium. Agilent arrays comprising 44,000 probes were used to analyse gene expression. Microarray analysis identified 1,088 genes differentially expressed in response to the conditioned medium at both 4 and 24 h (754 up-regulated, 334 down-regulated at 24 h); these included genes associated with inflammation and macrophage infiltration. A cluster of matrix metalloproteinase genes were highly up-regulated at both time-points, including MMP1, MMP3, MMP9, MMP10, MMP12 and MMP19. At 4 and 24 h, MMP1 was the most highly up-regulated gene (>2,400-fold increase in mRNA at 24 h). ELISA measurements indicated that substantial quantities of MMP1 and MMP3 were released from adipocytes incubated with conditioned medium, with little release by control adipocytes. Treatment with TNFalpha induced substantial increases in MMP1 (>100-fold) and MMP3 (27-fold) mRNA level and MMP1 and MMP3 release in adipocytes, suggesting that this cytokine could contribute to the stimulation of MMP expression by macrophages. In conclusion, macrophage-secreted factors induce a major inflammatory response in human adipocytes, with expression of MMP family members being strongly up-regulated. The induction of MMP1 and other MMPs suggests that macrophages stimulate tissue remodelling during adipose tissue expansion in obesity.
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Oita RC, Mazzatti DJ, Lim FL, Powell JR, Merry BJ. Whole-genome microarray analysis identifies up-regulation of Nr4a nuclear receptors in muscle and liver from diet-restricted rats. Mech Ageing Dev 2008; 130:240-7. [PMID: 19150624 DOI: 10.1016/j.mad.2008.12.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Revised: 11/13/2008] [Accepted: 12/12/2008] [Indexed: 11/16/2022]
Abstract
One of the most conserved methods to significantly increase lifespan in animals is through dietary restriction (DR). The mechanisms by which DR increases survival are controversial but are thought to include improvements in mitochondrial function concomitant with reductions in reactive oxygen species production and alterations in the insulin signalling pathway, resulting in global metabolic adaptation. In order to identify novel genes that may be important for lifespan extension of Brown Norway rats, we compared gene expression profiles from skeletal muscle of 28-month-old animals fed ad libitum or DR diets using whole-genome arrays. Following DR, 426 transcripts were significantly down-regulated whilst only 52 were up-regulated. Included in the up-regulated transcripts were three functionally related previously unidentified DR-regulated genes: Nr4a1, Nr4a2, and Nr4a3. Up-regulation of all three Nr4a receptors was also observed in liver - but not brain - of DR-fed animals. Furthermore, RT-PCR revealed up-regulation of several NR4A transcriptional targets (Ucp-3, Ampk-gamma3, Pgc-1alpha and Pgc-1beta) in skeletal muscle of DR animals. Due to the proposed roles of the NR4A nuclear receptors in sensing and responding to changes in the nutritional environment and in regulating glucose and lipid metabolism and insulin sensitivity, we hypothesise that these proteins may contribute to DR-induced metabolic adaptation.
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Affiliation(s)
- Radu C Oita
- Unilever R&D Colworth, Bedfordshire, United Kingdom
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