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Oudhoff H, Hisler V, Baumgartner F, Rees L, Grepper D, Jaźwińska A. Skeletal muscle regeneration after extensive cryoinjury of caudal myomeres in adult zebrafish. NPJ Regen Med 2024; 9:8. [PMID: 38378693 PMCID: PMC10879182 DOI: 10.1038/s41536-024-00351-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 01/24/2024] [Indexed: 02/22/2024] Open
Abstract
Skeletal muscles can regenerate after minor injuries, but severe structural damage often leads to fibrosis in mammals. Whether adult zebrafish possess the capacity to reproduce profoundly destroyed musculature remains unknown. Here, a new cryoinjury model revealed that several myomeres efficiently regenerated within one month after wounding the zebrafish caudal peduncle. Wound clearance involved accumulation of the selective autophagy receptor p62, an immune response and Collagen XII deposition. New muscle formation was associated with proliferation of Pax7 expressing muscle stem cells, which gave rise to MyoD1 positive myogenic precursors, followed by myofiber differentiation. Monitoring of slow and fast muscles revealed their coordinated replacement in the superficial and profound compartments of the myomere. However, the final boundary between the muscular components was imperfectly recapitulated, allowing myofibers of different identities to intermingle. The replacement of connective with sarcomeric tissues required TOR signaling, as rapamycin treatment impaired new muscle formation, leading to persistent fibrosis. The model of zebrafish myomere restoration may provide new medical perspectives for treatment of traumatic injuries.
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Affiliation(s)
- Hendrik Oudhoff
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700, Fribourg, Switzerland
| | - Vincent Hisler
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700, Fribourg, Switzerland
| | - Florian Baumgartner
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700, Fribourg, Switzerland
| | - Lana Rees
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700, Fribourg, Switzerland
| | - Dogan Grepper
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700, Fribourg, Switzerland
| | - Anna Jaźwińska
- Department of Biology, University of Fribourg, Chemin du Musée 10, 1700, Fribourg, Switzerland.
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Kim KM, Yoo GD, Heo W, Oh HT, Park J, Shin S, Do Y, Jeong MG, Hwang ES, Hong J. TAZ stimulates exercise-induced muscle satellite cell activation via Pard3-p38 MAPK-TAZ signalling axis. J Cachexia Sarcopenia Muscle 2023; 14:2733-2746. [PMID: 37923703 PMCID: PMC10751443 DOI: 10.1002/jcsm.13348] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 07/11/2023] [Accepted: 09/11/2023] [Indexed: 11/07/2023] Open
Abstract
BACKGROUND Exercise stimulates the activation of muscle satellite cells, which facilitate the maintenance of stem cells and their myogenic conversion during muscle regeneration. However, the underlying mechanism is not yet fully understood. This study shows that the transcriptional co-activator with PDZ-binding motif (TAZ) stimulates muscle regeneration via satellite cell activation. METHODS Tazf/f mice were crossed with the paired box gene 7 (Pax7)creERT2 mice to generate muscle satellite cell-specific TAZ knockout (sKO) mice. Mice were trained in an endurance exercise programme for 4 weeks. Regenerated muscles were harvested and analysed by haematoxylin and eosin staining. Muscle tissues were also analysed by immunofluorescence staining, immunoblot analysis and quantitative reverse transcription PCR (qRT-PCR). For the in vitro study, muscle satellite cells from wild-type and sKO mice were isolated and analysed. Mitochondrial DNA was quantified by qRT-PCR using primers that amplify the cyclooxygenase-2 region of mitochondrial DNA. Quiescent and activated satellite cells were stained with MitoTracker Red CMXRos to analyse mitochondria. To study the p38 mitogen-activated protein kinase (MAPK)-TAZ signalling axis, p38 MAPK was activated by introducing the MAPK kinase 6 plasmid into satellite cells and also inhibited by treatment with the p38 MAPK inhibitor, SB203580. RESULTS TAZ interacts with Pax7 to induce Myf5 expression and stimulates mammalian target of rapamycin signalling for satellite cell activation. In sKO mice, TAZ depletion reduces muscle satellite cell number by 38% (0.29 ± 0.073 vs. 0.18 ± 0.034, P = 0.0082) and muscle regeneration. After muscle injury, TAZ levels (2.59-fold, P < 0.0001) increase in committed cells compared to self-renewing cells during asymmetric satellite cell division. Mechanistically, the polarity protein Pard3 induces TAZ (2.01-fold, P = 0.008) through p38 MAPK, demonstrating that the p38 MAPK-TAZ axis is important for muscle regeneration. Physiologically, endurance exercise training induces muscle satellite cell activation and increases muscle fibre diameter (1.33-fold, 43.21 ± 23.59 vs. 57.68 ± 23.26 μm, P = 0.0004) with increased TAZ levels (1.76-fold, P = 0.017). However, sKO mice had a 39% reduction in muscle satellite cell number (0.20 ± 0.03 vs. 0.12 ± 0.02, P = 0.0013) and 24% reduction in muscle fibre diameter compared to wild-type mice (61.07 ± 23.33 vs. 46.60 ± 24.29 μm, P = 0.0006). CONCLUSIONS Our results demonstrate a novel mechanism of TAZ-induced satellite cell activation after muscle injury and exercise, suggesting that activation of TAZ in satellite cells may ameliorate the muscle ageing phenotype and may be an important target protein for the drug development in sarcopenia.
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Affiliation(s)
| | - Gi Don Yoo
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Woong Heo
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Ho Taek Oh
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Jeekeon Park
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Somin Shin
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Youjin Do
- Division of Life SciencesKorea UniversitySeoulKorea
| | - Mi Gyeong Jeong
- College of Pharmacy and Graduate School of Pharmaceutical SciencesEwha Womans UniversitySeoulKorea
| | - Eun Sook Hwang
- College of Pharmacy and Graduate School of Pharmaceutical SciencesEwha Womans UniversitySeoulKorea
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Wang K, Liufu S, Yu Z, Xu X, Ai N, Li X, Liu X, Chen B, Zhang Y, Ma H, Yin Y. miR-100-5p Regulates Skeletal Muscle Myogenesis through the Trib2/mTOR/S6K Signaling Pathway. Int J Mol Sci 2023; 24:ijms24108906. [PMID: 37240251 DOI: 10.3390/ijms24108906] [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: 04/20/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 05/28/2023] Open
Abstract
MicroRNAs (miRNAs) are endogenous small non-coding RNAs that play crucial regulatory roles in many biological processes, including the growth and development of skeletal muscle. miRNA-100-5p is often associated with tumor cell proliferation and migration. This study aimed to uncover the regulatory mechanism of miRNA-100-5p in myogenesis. In our study, we found that the miRNA-100-5p expression level was significantly higher in muscle tissue than in other tissues in pigs. Functionally, this study shows that miR-100-5p overexpression significantly promotes the proliferation and inhibits the differentiation of C2C12 myoblasts, whereas miR-100-5p inhibition results in the opposite effects. Bioinformatic analysis predicted that Trib2 has potential binding sites for miR-100-5p at the 3'UTR region. A dual-luciferase assay, qRT-qPCR, and Western blot confirmed that Trib2 is a target gene of miR-100-5p. We further explored the function of Trib2 in myogenesis and found that Trib2 knockdown markedly facilitated proliferation but suppressed the differentiation of C2C12 myoblasts, which is contrary to the effects of miR-100-5p. In addition, co-transfection experiments demonstrated that Trib2 knockdown could attenuate the effects of miR-100-5p inhibition on C2C12 myoblasts differentiation. In terms of the molecular mechanism, miR-100-5p suppressed C2C12 myoblasts differentiation by inactivating the mTOR/S6K signaling pathway. Taken together, our study results indicate that miR-100-5p regulates skeletal muscle myogenesis through the Trib2/mTOR/S6K signaling pathway.
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Affiliation(s)
- Kaiming Wang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Sui Liufu
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Zonggang Yu
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Xueli Xu
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Nini Ai
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Xintong Li
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Xiaolin Liu
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Bohe Chen
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Yuebo Zhang
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
| | - Haiming Ma
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China
| | - Yulong Yin
- College of Animal Science and Technology, Hunan Agricultural University, Changsha 410128, China
- Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China
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Sincennes MC, Brun CE. [GLI3 processing in the primary cilia of muscle stem cells controls their quiescence state]. Med Sci (Paris) 2023; 39:325-327. [PMID: 37094263 DOI: 10.1051/medsci/2023040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Affiliation(s)
- Marie-Claude Sincennes
- Centre Armand-Frappier Santé Biotechnologie, Institut national de la recherche scientifique (INRS), unité de recherche mixte INRS-UQAC en santé durable, Laval, Canada
| | - Caroline E Brun
- Institut NeuroMyoGène - Physiopathologie et génétique du neurone et du muscle (INMG-PGNM), CNRS UMR5261, Inserm U1315, université Claude Bernard Lyon 1, Lyon, France
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Direct Effects of Mifepristone on Mice Embryogenesis: An In Vitro Evaluation by Single-Embryo RNA Sequencing Analysis. Biomedicines 2023; 11:biomedicines11030907. [PMID: 36979886 PMCID: PMC10046204 DOI: 10.3390/biomedicines11030907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 03/09/2023] [Accepted: 03/11/2023] [Indexed: 03/17/2023] Open
Abstract
The clinical use of mifepristone for medical abortions has been established in 1987 in France and since 2000 in the United States. Mifepristone has a limited medical period that lasts <9 weeks of gestation, and the incidence of mifepristone treatment failure increases with gestation time. Mifepristone functions as an antagonist for progesterone and glucocorticoid receptors. Studies have confirmed that mifepristone treatments can directly contribute to endometrium disability by interfering with the endometrial receptivity of the embryo, thus causing decidual endometrial degeneration. However, whether mifepristone efficacy directly affects embryo survival and growth is still an open question. Some women choose to continue their pregnancy after mifepristone treatment fails, and some women express regret and seek medically unapproved mifepristone antagonization with high doses of progesterone. These unapproved treatments raise the potential risk of embryonic fatality and developmental anomalies. Accordingly, in the present study, we collected mouse blastocysts ex vivo and treated implanted blastocysts with mifepristone for 24 h. The embryos were further cultured to day 8 in vitro to finish their growth in the early somite stage, and the embryos were then collected for RNA sequencing (control n = 3, mifepristone n = 3). When we performed a gene set enrichment analysis, our data indicated that mifepristone treatment considerably altered the cellular pathways of embryos in terms of viability, proliferation, and development. The data indicated that mifepristone was involved in hallmark gene sets of protein secretion, mTORC1, fatty acid metabolism, IL-2-STAT5 signaling, adipogenesis, peroxisome, glycolysis, E2F targets, and heme metabolism. The data further revealed that mifepristone interfered with normal embryonic development. In sum, our data suggest that continuing a pregnancy after mifepristone treatment fails is inappropriate and infeasible. The results of our study reveal a high risk of fetus fatality and developmental problems when pregnancies are continued after mifepristone treatment fails.
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Ahmad SS, Chun HJ, Ahmad K, Shaikh S, Lim JH, Ali S, Han SS, Hur SJ, Sohn JH, Lee EJ, Choi I. The roles of growth factors and hormones in the regulation of muscle satellite cells for cultured meat production. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2023; 65:16-31. [PMID: 37093925 PMCID: PMC10119461 DOI: 10.5187/jast.2022.e114] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/25/2022] [Accepted: 11/27/2022] [Indexed: 12/24/2022]
Abstract
Cultured meat is a potential sustainable food generated by the in vitro myogenesis of muscle satellite (stem) cells (MSCs). The self-renewal and differentiation properties of MSCs are of primary interest for cultured meat production. MSC proliferation and differentiation are influenced by a variety of growth factors such as insulin-like growth factors (IGF-1 and IGF-2), transforming growth factor beta (TGF-β), fibroblast growth factors (FGF-2 and FGF-21), platelet-derived growth factor (PDGF) and hepatocyte growth factor (HGF) and by hormones like insulin, testosterone, glucocorticoids, and thyroid hormones. In this review, we investigated the roles of growth factors and hormones during cultured meat production because these factors provide signals for MSC growth and structural stability. The aim of this article is to provide the important idea about different growth factors such as FGF (enhance the cell proliferation and differentiation), IGF-1 (increase the number of myoblasts), PDGF (myoblast proliferation), TGF-β1 (muscle repair) and hormones such as insulin (cell survival and growth), testosterone (muscle fiber size), dexamethasone (myoblast proliferation and differentiation), and thyroid hormones (amount and diameter of muscle fibers and determine the usual pattern of fiber distributions) as media components during myogenesis for cultured meat production.
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Affiliation(s)
- Syed Sayeed Ahmad
- Department of Medical Biotechnology,
Yeungnam University, Gyeongsan 38541, Korea
- Research Institute of Cell Culture,
Yeungnam University, Gyeongsan 38541, Korea
| | - Hee Jin Chun
- Department of Medical Biotechnology,
Yeungnam University, Gyeongsan 38541, Korea
| | - Khurshid Ahmad
- Department of Medical Biotechnology,
Yeungnam University, Gyeongsan 38541, Korea
- Research Institute of Cell Culture,
Yeungnam University, Gyeongsan 38541, Korea
| | - Sibhghatulla Shaikh
- Department of Medical Biotechnology,
Yeungnam University, Gyeongsan 38541, Korea
- Research Institute of Cell Culture,
Yeungnam University, Gyeongsan 38541, Korea
| | - Jeong Ho Lim
- Department of Medical Biotechnology,
Yeungnam University, Gyeongsan 38541, Korea
- Research Institute of Cell Culture,
Yeungnam University, Gyeongsan 38541, Korea
| | - Shahid Ali
- Department of Medical Biotechnology,
Yeungnam University, Gyeongsan 38541, Korea
- Research Institute of Cell Culture,
Yeungnam University, Gyeongsan 38541, Korea
| | - Sung Soo Han
- Research Institute of Cell Culture,
Yeungnam University, Gyeongsan 38541, Korea
- School of Chemical Engineering, Yeungnam
University, Gyeongsan 38541, Korea
| | - Sun Jin Hur
- Department of Animal Science and
Technology, Chung-Ang University, Anseong 17546, Korea
| | - Jung Hoon Sohn
- Synthetic Biology and Bioengineering
Research Center, Korea Research Institute of Bioscience and Biotechnology
(KRIBB), Daejeon 34141, Korea
| | - Eun Ju Lee
- Department of Medical Biotechnology,
Yeungnam University, Gyeongsan 38541, Korea
- Research Institute of Cell Culture,
Yeungnam University, Gyeongsan 38541, Korea
| | - Inho Choi
- Department of Medical Biotechnology,
Yeungnam University, Gyeongsan 38541, Korea
- Research Institute of Cell Culture,
Yeungnam University, Gyeongsan 38541, Korea
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7
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Han X, Goh KY, Lee WX, Choy SM, Tang HW. The Importance of mTORC1-Autophagy Axis for Skeletal Muscle Diseases. Int J Mol Sci 2022; 24:297. [PMID: 36613741 PMCID: PMC9820406 DOI: 10.3390/ijms24010297] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/15/2022] [Accepted: 12/20/2022] [Indexed: 12/28/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR) complex 1, mTORC1, integrates nutrient and growth factor signals with cellular responses and plays critical roles in regulating cell growth, proliferation, and lifespan. mTORC1 signaling has been reported as a central regulator of autophagy by modulating almost all aspects of the autophagic process, including initiation, expansion, and termination. An increasing number of studies suggest that mTORC1 and autophagy are critical for the physiological function of skeletal muscle and are involved in diverse muscle diseases. Here, we review recent insights into the essential roles of mTORC1 and autophagy in skeletal muscles and their implications in human muscle diseases. Multiple inhibitors targeting mTORC1 or autophagy have already been clinically approved, while others are under development. These chemical modulators that target the mTORC1/autophagy pathways represent promising potentials to cure muscle diseases.
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Affiliation(s)
- Xujun Han
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Kah Yong Goh
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Wen Xing Lee
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Sze Mun Choy
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Hong-Wen Tang
- Program in Cancer and Stem Cell Biology, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
- Division of Cellular & Molecular Research, Humphrey Oei Institute of Cancer Research, National Cancer Centre Singapore, Singapore 169610, Singapore
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8
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Lu P, Morawong T, Molee A, Molee W. L-arginine alters myogenic genes expression but does not affect breast muscle characteristics by in ovo feeding technique in slow-growing chickens. Front Vet Sci 2022; 9:1030873. [PMID: 36590799 PMCID: PMC9794582 DOI: 10.3389/fvets.2022.1030873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 11/22/2022] [Indexed: 12/15/2022] Open
Abstract
In ovo feeding (IOF) of nutrients is a viable method for increasing muscle mass through hyperplasia and hypertrophy. The objective of this study was to evaluate the effects of IOF of L-arginine (Arg) on breast muscle weight, muscle morphology, amino acid profile, and gene expression of muscle development in slow-growing chickens. Four hundred eighty fertilized eggs were randomly divided into two groups: the first group was the non-injected control group, and the second group was the Arg group, injected with 1% Arg (0.5 mL) into the amnion on day 18 of incubation. After hatching, 160 birds from each group were randomly divided into four replicates of 40 birds each. This experiment lasted for 63 days. The results showed that IOF of Arg did not affect (P > 0.05) breast muscle weight, muscle morphology, and mRNA expression of mammalian target of rapamycin (mTOR) signaling pathway in slow-growing chickens. However, the amino acid profile of breast muscle was altered (P < 0.05) on the day of hatching (DOH), day 21 (D21), and day 42 (D42) post-hatch, respectively. Myogenic factor 5 (Myf5) mRNA expression was upregulated (P < 0.05) on D21 post-hatch. Myogenic regulator 4 (MRF4) mRNA expression was increased (P < 0.05) on DOH. And myogenin (MyoG) was increased (P < 0.05) on DOH and D21 post-hatch, in the Arg group compared to the control group. Overall, IOF of 1% Arg improved the expression of myogenic genes but did not influence muscle morphology and BMW. These results indicate that in ovo Arg dosage (0.5 mL/egg) has no adverse effect on breast muscle development of slow-growing chickens.
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Neuregulin-1/ErbB4 upregulates acetylcholine receptors via Akt/mTOR/p70S6K: a study in a rat model of obstetric brachial plexus palsy and in vitro. Acta Biochim Biophys Sin (Shanghai) 2022; 54:1648-1657. [PMID: 36331297 PMCID: PMC9828288 DOI: 10.3724/abbs.2022158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
In obstetric brachial plexus palsy (OBPP), the operative time window for nerve reconstruction of the intrinsic muscles of the hand (IMH) is much shorter than that of biceps. The reason is that the atrophy of IMH becomes irreversible more quickly than that of biceps. A previous study confirmed that the motor endplates of denervated intrinsic muscles of the forepaw (IMF) were destabilized, while those of denervated biceps remained intact. However, the specific molecular mechanism of regulating the self-repair of motor endplates is still unknown. In this study, we use a rat model of OBPP with right C5-C6 rupture plus C7-C8-T1 avulsion and left side as a control. Bilateral IMF and biceps are harvested at 5 weeks postinjury to assess relative protein and mRNA expression. We also use L6 skeletal myoblasts to verify the effects of signaling pathways regulating acetylcholine receptor (AChR) protein synthesis in vitro. The results show that in the OBPP rat model, the protein and mRNA expression levels of NRG-1/ErbB4 and phosphorylation of Akt/mTOR/p70S6K are lower in denervated IMF than in denervated biceps. In L6 myoblasts stimulated with NRG-1, overexpression and knockdown of ErbB4 lead to upregulation and downregulation of AChR subunit protein synthesis and Akt/mTOR/p70S6K phosphorylation, respectively. Inhibition of mTOR abolishes protein synthesis of AChR subunits elevated by NRG-1/ErbB4. Our findings suggest that in the OBPP rat model, lower expression of AChR subunits in the motor endplates of denervated IMF is associated with downregulation of NRG-1/ErbB4 and phosphorylation of Akt/mTOR/p70S6K. NRG-1/ErbB4 can promote protein synthesis of the AChR subunits in L6 myoblasts via phosphorylation of Akt/mTOR/p70S6K.
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10
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Cai H, Wang Z, Tang W, Ke X, Zhao E. Recent advances of the mammalian target of rapamycin signaling in mesenchymal stem cells. Front Genet 2022; 13:970699. [PMID: 36110206 PMCID: PMC9468880 DOI: 10.3389/fgene.2022.970699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 08/11/2022] [Indexed: 11/22/2022] Open
Abstract
Mammalian target of rapamycin (mTOR) is a serine/threonine kinase involved in a variety of cellular functions, such as cell proliferation, metabolism, autophagy, survival and cytoskeletal organization. Furthermore, mTOR is made up of three multisubunit complexes, mTOR complex 1, mTOR complex 2, and putative mTOR complex 3. In recent years, increasing evidence has suggested that mTOR plays important roles in the differentiation and immune responses of mesenchymal stem cells (MSCs). In addition, mTOR is a vital regulator of pivotal cellular and physiological functions, such as cell metabolism, survival and ageing, where it has emerged as a novel therapeutic target for ageing-related diseases. Therefore, the mTOR signaling may develop a large impact on the treatment of ageing-related diseases with MSCs. In this review, we discuss prospects for future research in this field.
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Affiliation(s)
- Huarui Cai
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
| | - Zhongze Wang
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
| | - Wenhan Tang
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
| | - Xiaoxue Ke
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
- *Correspondence: Xiaoxue Ke, ; Erhu Zhao,
| | - Erhu Zhao
- State Key Laboratory of Silkworm Genome Biology, College of Sericulture, Textile and Biomass Sciences, Southwest University, Chongqing, China
- Cancer Center, Medical Research Institute, Southwest University, Chongqing, China
- *Correspondence: Xiaoxue Ke, ; Erhu Zhao,
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11
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Jin J, Du M, Wang J, Guo Y, Zhang J, Zuo H, Hou Y, Wang S, Lv W, Bai W, Wang J, Zhan X, Peng Y, Tong Q, Chai J, Xu Z, Zuo B. Conservative analysis of Synaptopodin-2 intron sense-overlapping lncRNA reveals its novel function in promoting muscle atrophy. J Cachexia Sarcopenia Muscle 2022; 13:2017-2030. [PMID: 35592920 PMCID: PMC9397560 DOI: 10.1002/jcsm.13012] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 03/31/2022] [Accepted: 04/25/2022] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Dissection of the regulatory pathways that control skeletal muscle development and atrophy is important for the treatment of muscle wasting. Long noncoding RNA (lncRNA) play important roles in various stages of muscle development. We previously reported that Synaptopodin-2 (SYNPO2) intron sense-overlapping lncRNA (SYISL) regulates myogenesis through an interaction with enhancer of zeste homologue 2 (EZH2). However, it remains unclear whether SYISL homologues exist in humans and pigs, and whether the functions and mechanisms of these homologues are conserved among species. METHODS Bioinformatics, cell fractionation, and quantitative real-time polymerase chain reaction (qRT-PCR) analyses were used for the identification and molecular characterization of SYISL homologues in humans and pigs. Effects on myogenesis and muscle atrophy were determined via loss-of-function or gain-of-function experiments using C2C12 myoblasts, myogenic progenitor cells, dexamethasone (DEX), and aging-induced muscle atrophy models. RNA pulldown, RNA immunoprecipitation, dual luciferase reporting, and co-transfection experiments were used to explore the mechanisms of SYISL interactions with proteins and miRNAs. RESULTS We identified SYISL homologues in humans (designated hSYISL) and pigs (designated pSYISL). Functional experiments demonstrated that hSYISL and pSYISL regulate myogenesis through interactions with EZH2. Interestingly, we showed that SYISL functions to regulate muscle atrophy and sarcopenia through comparative analysis. SYISL is significantly up-regulated after muscle atrophy (P < 0.01); it significantly promotes muscle atrophy in DEX-induced muscle atrophy models (P < 0.01). SYISL knockdown or knockout alleviates muscle atrophy and sarcopenia in DEX-induced and aged mice. The tibialis anterior (TA) muscle weight of 3-month-old wild-type (WT) mice decreased by 33.24% after DEX treatment (P < 0.001), while the muscle weight loss of 3-month-old SYISL knockout mice was only 18.20% after DEX treatment (P < 0.001). SYISL knockout in 18-month-old WT mice significantly increased the weights of quadriceps (Qu), gastrocnemius (Gas), and TA muscles by 10.45% (P < 0.05), 13.95% (P < 0.01), and 24.82% (P < 0.05), respectively. Mechanistically, SYISL increases the expression levels of the muscle atrophy genes forkhead box protein O3a (FoxO3a), muscle ring finger 1 (MuRF1), and muscle atrophy-related F-box (Atrogin-1) via sponging of miR-23a-3p/miR-103-3p/miR-205-5p and thus promotes muscle atrophy. Additionally, we verified that human SYISL overexpression in muscles of 18-month-old WT mice significantly decreased the weights of Gas, Qu, and TA muscles by 7.76% (P < 0.01), 12.26% (P < 0.05), and 13.44% (P < 0.01), respectively, and accelerates muscle atrophy through conserved mechanisms. CONCLUSIONS Our results identify SYISL as a conserved lncRNA that modulates myogenesis in mice, pigs, and humans. We also demonstrated its previously unknown ability to promote muscle atrophy.
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Affiliation(s)
- Jianjun Jin
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Animal Genetics, Breeding and Reproduction of Shaanxi Province, Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Mengmeng Du
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Jian Wang
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Yubo Guo
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Jiali Zhang
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Hao Zuo
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Yunqing Hou
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Shanshan Wang
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Wei Lv
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Wei Bai
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Jin Wang
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Xizhen Zhan
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Yaxin Peng
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Qian Tong
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Jin Chai
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China
| | - Zaiyan Xu
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Department of Basic Veterinary Medicine, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, China
| | - Bo Zuo
- Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Agriculture Animal Genetics, Breeding and Reproduction of the Ministry of Education, Huazhong Agricultural University, Wuhan, China.,Hubei Hongshan Laboratory, Wuhan, China.,The Cooperative Innovation Center for Sustainable Pig Production, Wuhan, China.,Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Wuhan, China.,Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
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12
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Brun CE, Sincennes MC, Lin AYT, Hall D, Jarassier W, Feige P, Le Grand F, Rudnicki MA. GLI3 regulates muscle stem cell entry into G Alert and self-renewal. Nat Commun 2022; 13:3961. [PMID: 35803939 PMCID: PMC9270324 DOI: 10.1038/s41467-022-31695-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 06/27/2022] [Indexed: 12/12/2022] Open
Abstract
Satellite cells are required for the growth, maintenance, and regeneration of skeletal muscle. Quiescent satellite cells possess a primary cilium, a structure that regulates the processing of the GLI family of transcription factors. Here we find that GLI3 processing by the primary cilium plays a critical role for satellite cell function. GLI3 is required to maintain satellite cells in a G0 dormant state. Strikingly, satellite cells lacking GLI3 enter the GAlert state in the absence of injury. Furthermore, GLI3 depletion stimulates expansion of the stem cell pool. As a result, satellite cells lacking GLI3 display rapid cell-cycle entry, increased proliferation and augmented self-renewal, and markedly enhanced regenerative capacity. At the molecular level, we establish that the loss of GLI3 induces mTORC1 signaling activation. Therefore, our results provide a mechanism by which GLI3 controls mTORC1 signaling, consequently regulating muscle stem cell activation and fate.
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Affiliation(s)
- Caroline E Brun
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Marie-Claude Sincennes
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Alexander Y T Lin
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Derek Hall
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - William Jarassier
- Univ Lyon, Univ Lyon 1, CNRS, INSERM, Pathophysiology and Genetics of Neuron and Muscle, UMR5261, U1315, Institut NeuroMyoGène, 69008, Lyon, France
| | - Peter Feige
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada
| | - Fabien Le Grand
- Univ Lyon, Univ Lyon 1, CNRS, INSERM, Pathophysiology and Genetics of Neuron and Muscle, UMR5261, U1315, Institut NeuroMyoGène, 69008, Lyon, France
| | - Michael A Rudnicki
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, ON, K1H 8L6, Canada.
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
- Department of Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, K1H 8M5, Canada.
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13
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Gugliuzza MV, Crist C. Muscle stem cell adaptations to cellular and environmental stress. Skelet Muscle 2022; 12:5. [PMID: 35151369 PMCID: PMC8840228 DOI: 10.1186/s13395-022-00289-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/30/2022] [Indexed: 12/21/2022] Open
Abstract
Background Lifelong regeneration of the skeletal muscle is dependent on a rare population of resident skeletal muscle stem cells, also named ‘satellite cells’ for their anatomical position on the outside of the myofibre and underneath the basal lamina. Muscle stem cells maintain prolonged quiescence, but activate the myogenic programme and the cell cycle in response to injury to expand a population of myogenic progenitors required to regenerate muscle. The skeletal muscle does not regenerate in the absence of muscle stem cells. Main body The notion that lifelong regeneration of the muscle is dependent on a rare, non-redundant population of stem cells seems contradictory to accumulating evidence that muscle stem cells have activated multiple stress response pathways. For example, muscle stem cell quiescence is mediated in part by the eIF2α arm of the integrated stress response and by negative regulators of mTORC1, two translational control pathways that downregulate protein synthesis in response to stress. Muscle stem cells also activate pathways to protect against DNA damage, heat shock, and environmental stress. Here, we review accumulating evidence that muscle stem cells encounter stress during their prolonged quiescence and their activation. While stress response pathways are classically described to be bimodal whereby a threshold dictates cell survival versus cell death responses to stress, we review evidence that muscle stem cells additionally respond to stress by spontaneous activation and fusion to myofibres. Conclusion We propose a cellular stress test model whereby the prolonged state of quiescence and the microenvironment serve as selective pressures to maintain muscle stem cell fitness, to safeguard the lifelong regeneration of the muscle. Fit muscle stem cells that maintain robust stress responses are permitted to maintain the muscle stem cell pool. Unfit muscle stem cells are depleted from the pool first by spontaneous activation, or in the case of severe stress, by activating cell death or senescence pathways.
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14
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A Long Journey before Cycling: Regulation of Quiescence Exit in Adult Muscle Satellite Cells. Int J Mol Sci 2022; 23:ijms23031748. [PMID: 35163665 PMCID: PMC8836154 DOI: 10.3390/ijms23031748] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 01/28/2022] [Accepted: 01/30/2022] [Indexed: 02/04/2023] Open
Abstract
Skeletal muscle harbors a pool of stem cells called muscle satellite cells (MuSCs) that are mainly responsible for its robust regenerative capacities. Adult satellite cells are mitotically quiescent in uninjured muscles under homeostasis, but they exit quiescence upon injury to re-enter the cell cycle to proliferate. While most of the expanded satellites cells differentiate and fuse to form new myofibers, some undergo self-renewal to replenish the stem cell pool. Specifically, quiescence exit describes the initial transition of MuSCs from quiescence to the first cell cycle, which takes much longer than the time required for subsequent cell cycles and involves drastic changes in cell size, epigenetic and transcriptomic profiles, and metabolic status. It is, therefore, an essential period indispensable for the success of muscle regeneration. Diverse mechanisms exist in MuSCs to regulate quiescence exit. In this review, we summarize key events that occur during quiescence exit in MuSCs and discuss the molecular regulation of this process with an emphasis on multiple levels of intrinsic regulatory mechanisms. A comprehensive understanding of how quiescence exit is regulated will facilitate satellite cell-based muscle regenerative therapies and advance their applications in various disease and aging conditions.
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15
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Franck S, Couvreu De Deckersberg E, Bubenik JL, Markouli C, Barbé L, Allemeersch J, Hilven P, Duqué G, Swanson MS, Gheldof A, Spits C, Sermon KD. Myotonic dystrophy type 1 embryonic stem cells show decreased myogenic potential, increased CpG methylation at the DMPK locus and RNA mis-splicing. Biol Open 2022; 11:273965. [PMID: 35019138 PMCID: PMC8764412 DOI: 10.1242/bio.058978] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/29/2021] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle tissue is severely affected in myotonic dystrophy type 1 (DM1) patients, characterised by muscle weakness, myotonia and muscle immaturity in the most severe congenital form of the disease. Previously, it was not known at what stage during myogenesis the DM1 phenotype appears. In this study we differentiated healthy and DM1 human embryonic stem cells to myoblasts and myotubes and compared their differentiation potential using a comprehensive multi-omics approach. We found myogenesis in DM1 cells to be abnormal with altered myotube generation compared to healthy cells. We did not find differentially expressed genes between DM1 and non-DM1 cell lines within the same developmental stage. However, during differentiation we observed an aberrant inflammatory response and increased CpG methylation upstream of the CTG repeat at the myoblast level and RNA mis-splicing at the myotube stage. We show that early myogenesis modelled in hESC reiterates the early developmental manifestation of DM1. Summary: Early developmental abnormalities in myotonic dystrophy type 1 are reiterated in vitro in myotubes differentiated from human embryonic stem cells that carry the mutation.
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Affiliation(s)
- Silvie Franck
- Department Reproduction and Genetics, Vrije Universiteit Brussel, Brussels 1090, Belgium
| | | | - Jodi L Bubenik
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Christina Markouli
- Department Reproduction and Genetics, Vrije Universiteit Brussel, Brussels 1090, Belgium
| | - Lise Barbé
- Center for Systems and Therapeutics, Gladstone Institutes, San Francisco, 94107 CA, United States
| | | | - Pierre Hilven
- Department Reproduction and Genetics, Vrije Universiteit Brussel, Brussels 1090, Belgium
| | - Geoffrey Duqué
- Department Reproduction and Genetics, Vrije Universiteit Brussel, Brussels 1090, Belgium
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL 32610, USA
| | - Alexander Gheldof
- Department Reproduction and Genetics, Vrije Universiteit Brussel, Brussels 1090, Belgium.,Center for Medical Genetics, UZ Brussel, Brussels 1090, Belgium
| | - Claudia Spits
- Department Reproduction and Genetics, Vrije Universiteit Brussel, Brussels 1090, Belgium
| | - Karen D Sermon
- Department Reproduction and Genetics, Vrije Universiteit Brussel, Brussels 1090, Belgium
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16
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Function and regulation of muscle stem cells in skeletal muscle development and regeneration: a narrative review. JOURNAL OF BIO-X RESEARCH 2021. [DOI: 10.1097/jbr.0000000000000105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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17
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Kapoor S, Subba P, Shenoy P S, Bose B. Sca1 + Progenitor Cells (Ex vivo) Exhibits Differential Proteomic Signatures From the Culture Adapted Sca1 + Cells (In vitro), Both Isolated From Murine Skeletal Muscle Tissue. Stem Cell Rev Rep 2021; 17:1754-1767. [PMID: 33742350 DOI: 10.1007/s12015-021-10134-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2021] [Indexed: 10/21/2022]
Abstract
Stem cell antigen-1 (Sca-1) is a glycosyl-phosphatidylinositol-anchored membrane protein that is expressed in a sub-population of muscle stem and progenitor cell types. Reportedly, Sca-1 regulates the myogenic property of myoblasts and Sca-1-/- mice exhibited defective muscle regeneration. Although the role of Sca-1 in muscle development and maintenance is well-acknowledged, molecular composition of muscle derived Sca-1+ cells is not characterized. Here, we applied a high-resolution mass spectrometry-based workflow to characterize the proteomic landscape of mouse hindlimb skeletal muscle derived Sca-1+ cells. Furthermore, we characterized the impact of the cellular microenvironments on the proteomes of Sca-1+ cells. The proteome component of freshly isolated Sca-1+ cells (ex vivo) was compared with that of Sca-1+ cells expanded in cell culture (in vitro). The analysis revealed significant differences in the protein abundances in the two conditions reflective of their functional variations. The identified proteins were enriched in various biological pathways. Notably, we identified proteins related to myotube differentiation, myotube cell development and myoblast fusion. We also identified a panel of cell surface marker proteins that can be leveraged in future to enrich Sca-1+ cells using combinatorial strategies. Comparative analysis implicated the activation of various pathways leading to increased protein synthesis under in vitro condition. We report here the most comprehensive proteome map of Sca-1+ cells that provides insights into the molecular networks operative in Sca-1+ cells. Importantly, through our work we generated the proteomic blueprint of protein abundances significantly altered in Sca-1+ cells under ex vivo and in vitro conditions. The curated data can also be visualized at https://yenepoya.res.in/database/Sca-1-Proteomics .
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Affiliation(s)
- Saketh Kapoor
- Stem Cells and Regenerative Medicine Centre, Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, Karnataka, 575018, India
| | - Pratigya Subba
- Center for Systems Biology and Molecular Medicine, Yenepoya Research Centre, Yenepoya (Deemed to be University), Deralakatte, Mangalore, Karnataka, 575018, India
| | - Sudheer Shenoy P
- Stem Cells and Regenerative Medicine Centre, Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, Karnataka, 575018, India.
| | - Bipasha Bose
- Stem Cells and Regenerative Medicine Centre, Yenepoya Research Centre, Yenepoya (Deemed to be University), University Road, Deralakatte, Mangalore, Karnataka, 575018, India.
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18
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Solsona R, Pavlin L, Bernardi H, Sanchez AMJ. Molecular Regulation of Skeletal Muscle Growth and Organelle Biosynthesis: Practical Recommendations for Exercise Training. Int J Mol Sci 2021; 22:2741. [PMID: 33800501 PMCID: PMC7962973 DOI: 10.3390/ijms22052741] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 12/18/2022] Open
Abstract
The regulation of skeletal muscle mass and organelle homeostasis is dependent on the capacity of cells to produce proteins and to recycle cytosolic portions. In this investigation, the mechanisms involved in skeletal muscle mass regulation-especially those associated with proteosynthesis and with the production of new organelles-are presented. Thus, the critical roles of mammalian/mechanistic target of rapamycin complex 1 (mTORC1) pathway and its regulators are reviewed. In addition, the importance of ribosome biogenesis, satellite cells involvement, myonuclear accretion, and some major epigenetic modifications related to protein synthesis are discussed. Furthermore, several studies conducted on the topic of exercise training have recognized the central role of both endurance and resistance exercise to reorganize sarcomeric proteins and to improve the capacity of cells to build efficient organelles. The molecular mechanisms underlying these adaptations to exercise training are presented throughout this review and practical recommendations for exercise prescription are provided. A better understanding of the aforementioned cellular pathways is essential for both healthy and sick people to avoid inefficient prescriptions and to improve muscle function with emergent strategies (e.g., hypoxic training). Finally, current limitations in the literature and further perspectives, notably on epigenetic mechanisms, are provided to encourage additional investigations on this topic.
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Affiliation(s)
- Robert Solsona
- Laboratoire Interdisciplinaire Performance Santé Environnement de Montagne (LIPSEM), Faculty of Sports Sciences, University of Perpignan Via Domitia, UR 4640, 7 Avenue Pierre de Coubertin, 66120 Font-Romeu, France;
| | - Laura Pavlin
- DMEM, University of Montpellier, INRAE UMR866, 2 Place Pierre Viala, 34060 Montpellier, France; (L.P.); (H.B.)
| | - Henri Bernardi
- DMEM, University of Montpellier, INRAE UMR866, 2 Place Pierre Viala, 34060 Montpellier, France; (L.P.); (H.B.)
| | - Anthony MJ Sanchez
- Laboratoire Interdisciplinaire Performance Santé Environnement de Montagne (LIPSEM), Faculty of Sports Sciences, University of Perpignan Via Domitia, UR 4640, 7 Avenue Pierre de Coubertin, 66120 Font-Romeu, France;
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19
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Millward DJ. Interactions between Growth of Muscle and Stature: Mechanisms Involved and Their Nutritional Sensitivity to Dietary Protein: The Protein-Stat Revisited. Nutrients 2021; 13:729. [PMID: 33668846 PMCID: PMC7996181 DOI: 10.3390/nu13030729] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Revised: 02/15/2021] [Accepted: 02/22/2021] [Indexed: 02/07/2023] Open
Abstract
Childhood growth and its sensitivity to dietary protein is reviewed within a Protein-Stat model of growth regulation. The coordination of growth of muscle and stature is a combination of genetic programming, and of two-way mechanical interactions involving the mechanotransduction of muscle growth through stretching by bone length growth, the core Protein-Stat feature, and the strengthening of bone through muscle contraction via the mechanostat. Thus, growth in bone length is the initiating event and this is always observed. Endocrine and cellular mechanisms of growth in stature are reviewed in terms of the growth hormone-insulin like growth factor-1 (GH-IGF-1) and thyroid axes and the sex hormones, which together mediate endochondral ossification in the growth plate and bone lengthening. Cellular mechanisms of muscle growth during development are then reviewed identifying (a) the difficulties posed by the need to maintain its ultrastructure during myofibre hypertrophy within the extracellular matrix and the concept of muscle as concentric "bags" allowing growth to be conceived as bag enlargement and filling, (b) the cellular and molecular mechanisms involved in the mechanotransduction of satellite and mesenchymal stromal cells, to enable both connective tissue remodelling and provision of new myonuclei to aid myofibre hypertrophy and (c) the implications of myofibre hypertrophy for protein turnover within the myonuclear domain. Experimental data from rodent and avian animal models illustrate likely changes in DNA domain size and protein turnover during developmental and stretch-induced muscle growth and between different muscle fibre types. Growth of muscle in male rats during adulthood suggests that "bag enlargement" is achieved mainly through the action of mesenchymal stromal cells. Current understanding of the nutritional regulation of protein deposition in muscle, deriving from experimental studies in animals and human adults, is reviewed, identifying regulation by amino acids, insulin and myofibre volume changes acting to increase both ribosomal capacity and efficiency of muscle protein synthesis via the mechanistic target of rapamycin complex 1 (mTORC1) and the phenomenon of a "bag-full" inhibitory signal has been identified in human skeletal muscle. The final section deals with the nutritional sensitivity of growth of muscle and stature to dietary protein in children. Growth in length/height as a function of dietary protein intake is described in the context of the breastfed child as the normative growth model, and the "Early Protein Hypothesis" linking high protein intakes in infancy to later adiposity. The extensive paediatric studies on serum IGF-1 and child growth are reviewed but their clinical relevance is of limited value for understanding growth regulation; a role in energy metabolism and homeostasis, acting with insulin to mediate adiposity, is probably more important. Information on the influence of dietary protein on muscle mass per se as opposed to lean body mass is limited but suggests that increased protein intake in children is unable to promote muscle growth in excess of that linked to genotypic growth in length/height. One possible exception is milk protein intake, which cohort and cross-cultural studies suggest can increase height and associated muscle growth, although such effects have yet to be demonstrated by randomised controlled trials.
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Affiliation(s)
- D Joe Millward
- Department of Nutritional Sciences, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
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20
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Abstract
Blood is generated throughout life by continued proliferation and differentiation of hematopoietic progenitors, while at the top of the hierarchy, hematopoietic stem cells (HSCs) remain largely quiescent. This way HSCs avoid senescence and preserve their capacity to repopulate the hematopoietic system. But HSCs are not always quiescent, proliferating extensively in conditions such as those found in the fetal liver. Understanding the elusive mechanisms that regulate HSC fate would enable us to comprehend a crucial piece of HSC biology and pave the way for ex-vivo HSC expansion with clear clinical benefit. Here we review how metabolism, endoplasmic reticulum stress and oxidative stress condition impact HSCs decision to self-renew or differentiate and how these signals integrate into the mammalian target of rapamycin (mTOR) pathway. We argue that the bone marrow microenvironment continuously favors differentiation through the activation of the mTOR complex (mTORC)1 signaling, while the fetal liver microenvironment favors self-renewal through the inverse mechanism. In addition, we also postulate that strategies that have successfully achieved HSC expansion, directly or indirectly, lead to the inactivation of mTORC1. Finally, we propose a mechanism by which mTOR signaling, during cell division, conditions HSC fate. This mechanism has already been demonstrated in mature hematopoietic cells (T-cells), that face a similar decision after activation, either undergoing clonal expansion or differentiation.
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21
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Relaix F, Bencze M, Borok MJ, Der Vartanian A, Gattazzo F, Mademtzoglou D, Perez-Diaz S, Prola A, Reyes-Fernandez PC, Rotini A, Taglietti. Perspectives on skeletal muscle stem cells. Nat Commun 2021; 12:692. [PMID: 33514709 PMCID: PMC7846784 DOI: 10.1038/s41467-020-20760-6] [Citation(s) in RCA: 158] [Impact Index Per Article: 52.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 12/17/2020] [Indexed: 01/30/2023] Open
Abstract
Skeletal muscle has remarkable regeneration capabilities, mainly due to its resident muscle stem cells (MuSCs). In this review, we introduce recently developed technologies and the mechanistic insights they provide to the understanding of MuSC biology, including the re-definition of quiescence and Galert states. Additionally, we present recent studies that link MuSC function with cellular heterogeneity, highlighting the complex regulation of self-renewal in regeneration, muscle disorders and aging. Finally, we discuss MuSC metabolism and its role, as well as the multifaceted regulation of MuSCs by their niche. The presented conceptual advances in the MuSC field impact on our general understanding of stem cells and their therapeutic use in regenerative medicine.
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Affiliation(s)
- F. Relaix
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France ,EnvA, IMRB, 94700 Maisons-Alfort, France ,grid.462410.50000 0004 0386 3258EFS, IMRB, 94010 Creteil, France ,grid.50550.350000 0001 2175 4109AP-HP, Hopital Mondor, Service d’histologie, 94010 Creteil, France
| | - M. Bencze
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France
| | - M. J. Borok
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France
| | - A. Der Vartanian
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France
| | - F. Gattazzo
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France ,grid.462410.50000 0004 0386 3258EFS, IMRB, 94010 Creteil, France
| | - D. Mademtzoglou
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France
| | - S. Perez-Diaz
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France
| | - A. Prola
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France ,EnvA, IMRB, 94700 Maisons-Alfort, France
| | - P. C. Reyes-Fernandez
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France
| | - A. Rotini
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France
| | - Taglietti
- grid.462410.50000 0004 0386 3258Univ Paris Est Creteil, INSERM, IMRB, 94010 Creteil, France
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22
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O'Neill EN, Cosenza ZA, Baar K, Block DE. Considerations for the development of cost-effective cell culture media for cultivated meat production. Compr Rev Food Sci Food Saf 2020; 20:686-709. [PMID: 33325139 DOI: 10.1111/1541-4337.12678] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/30/2020] [Accepted: 11/03/2020] [Indexed: 12/28/2022]
Abstract
Innovation in cultivated meat development has been rapidly accelerating in recent years because it holds the potential to help attenuate issues facing production of dietary protein for a growing world population. There are technical obstacles still hindering large-scale commercialization of cultivated meat, of which many are related to the media that are used to culture the muscle, fat, and connective tissue cells. While animal cell culture media has been used and refined for roughly a century, it has not been specifically designed with the requirements of cultivated meat in mind. Perhaps the most common industrial use of animal cell culture is currently the production of therapeutic monoclonal antibodies, which sell for orders of magnitude more than meat. Successful production of cultivated meat requires media that is food grade with minimal cost, can regulate large-scale cell proliferation and differentiation, has acceptable sensory qualities, and is animal ingredient-free. Much insight into strategies for achieving media formulations with these qualities can be obtained from knowledge of conventional culture media applications and from the metabolic pathways involved in myogenesis and protein synthesis. In addition, application of principles used to optimize media for large-scale microbial fermentation processes producing lower value commodity chemicals and food ingredients can also be instructive. As such, the present review shall provide an overview of the current understanding of cell culture media as it relates to cultivated meat.
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Affiliation(s)
- Edward N O'Neill
- Department of Food Science and Technology, University of California, Davis, California.,Department of Viticulture and Enology, University of California, Davis, California
| | - Zachary A Cosenza
- Department of Viticulture and Enology, University of California, Davis, California.,Department of Chemical Engineering, University of California, Davis, California
| | - Keith Baar
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California.,Department of Physiology and Membrane Biology, University of California, Davis, California
| | - David E Block
- Department of Viticulture and Enology, University of California, Davis, California.,Department of Chemical Engineering, University of California, Davis, California
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23
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Manickam N, Radhakrishnan RK, Vergil Andrews JF, Selvaraj DB, Kandasamy M. Cell cycle re-entry of neurons and reactive neuroblastosis in Huntington's disease: Possibilities for neural-glial transition in the brain. Life Sci 2020; 263:118569. [PMID: 33049278 DOI: 10.1016/j.lfs.2020.118569] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 09/29/2020] [Accepted: 10/02/2020] [Indexed: 02/07/2023]
Abstract
Huntington's disease (HD) is an autosomal dominant pathogenic condition that causes progressive degeneration of GABAergic neurons in the brain. The abnormal expansion of the CAG repeats in the exon 1 of the Huntingtin gene (HTT gene) has been associated with the onset and progression of movement disorders, psychiatric disturbance and cognitive decline in HD. Microglial activation and reactive astrogliosis have been recognized as the key pathogenic cellular events in the brains of HD subjects. Besides, HD has been characterized by induced quiescence of neural stem cells (NSCs), reactive neuroblastosis and reduced survival of newborn neurons in the brain. Strikingly, the expression of the mutant HTT gene has been reported to induce the cell cycle re-entry of neurons in HD brains. However, the underlying basis for the induction of cell cycle in neurons and the fate of dedifferentiating neurons in the pathological brain remain largely unknown. Thus, this review article revisits the reports on the regulation of key signaling pathways responsible for altered cell cycle events in diseased brains, with special reference to HD and postulates the occurrence of reactive neuroblastosis as a consequential cellular event of dedifferentiation of neurons. Meanwhile, a substantial number of studies indicate that many neuropathogenic events are associated with the expression of potential glial cell markers by neuroblasts. Taken together, this article represents a hypothesis that transdifferentiation of neurons into glial cells might be highly possible through the transient generation of reactive neuroblasts in the brain upon certain pathological conditions.
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Affiliation(s)
- Nivethitha Manickam
- Laboratory of Stem Cells and Neuroregeneration, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India
| | - Risna Kanjirassery Radhakrishnan
- Laboratory of Stem Cells and Neuroregeneration, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India
| | - Jemi Feiona Vergil Andrews
- Laboratory of Stem Cells and Neuroregeneration, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India
| | - Divya Bharathi Selvaraj
- Laboratory of Stem Cells and Neuroregeneration, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India
| | - Mahesh Kandasamy
- Laboratory of Stem Cells and Neuroregeneration, Department of Animal Science, School of Life Sciences, Bharathidasan University, Tiruchirappalli 620024, Tamil Nadu, India; Faculty Recharge Programme, University Grants Commission (UGC-FRP), New Delhi 110002, India.
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24
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The neuromuscular junction is a focal point of mTORC1 signaling in sarcopenia. Nat Commun 2020; 11:4510. [PMID: 32908143 PMCID: PMC7481251 DOI: 10.1038/s41467-020-18140-1] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 08/05/2020] [Indexed: 12/21/2022] Open
Abstract
With human median lifespan extending into the 80s in many developed countries, the societal burden of age-related muscle loss (sarcopenia) is increasing. mTORC1 promotes skeletal muscle hypertrophy, but also drives organismal aging. Here, we address the question of whether mTORC1 activation or suppression is beneficial for skeletal muscle aging. We demonstrate that chronic mTORC1 inhibition with rapamycin is overwhelmingly, but not entirely, positive for aging mouse skeletal muscle, while genetic, muscle fiber-specific activation of mTORC1 is sufficient to induce molecular signatures of sarcopenia. Through integration of comprehensive physiological and extensive gene expression profiling in young and old mice, and following genetic activation or pharmacological inhibition of mTORC1, we establish the phenotypically-backed, mTORC1-focused, multi-muscle gene expression atlas, SarcoAtlas (https://sarcoatlas.scicore.unibas.ch/), as a user-friendly gene discovery tool. We uncover inter-muscle divergence in the primary drivers of sarcopenia and identify the neuromuscular junction as a focal point of mTORC1-driven muscle aging.
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Castets P, Ham DJ, Rüegg MA. The TOR Pathway at the Neuromuscular Junction: More Than a Metabolic Player? Front Mol Neurosci 2020; 13:162. [PMID: 32982690 PMCID: PMC7485269 DOI: 10.3389/fnmol.2020.00162] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/05/2020] [Indexed: 12/18/2022] Open
Abstract
The neuromuscular junction (NMJ) is the chemical synapse connecting motor neurons and skeletal muscle fibers. NMJs allow all voluntary movements, and ensure vital functions like breathing. Changes in the structure and function of NMJs are hallmarks of numerous pathological conditions that affect muscle function including sarcopenia, the age-related loss of muscle mass and function. However, the molecular mechanisms leading to the morphological and functional perturbations in the pre- and post-synaptic compartments of the NMJ remain poorly understood. Here, we discuss the role of the metabolic pathway associated to the kinase TOR (Target of Rapamycin) in the development, maintenance and alterations of the NMJ. This is of particular interest as the TOR pathway has been implicated in aging, but its role at the NMJ is still ill-defined. We highlight the respective functions of the two TOR-associated complexes, TORC1 and TORC2, and discuss the role of localized protein synthesis and autophagy regulation in motor neuron terminals and sub-synaptic regions of muscle fibers and their possible effects on NMJ maintenance.
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Affiliation(s)
- Perrine Castets
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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26
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Bouquier N, Moutin E, Tintignac LA, Reverbel A, Jublanc E, Sinnreich M, Chastagnier Y, Averous J, Fafournoux P, Verpelli C, Boeckers T, Carnac G, Perroy J, Ollendorff V. AIMTOR, a BRET biosensor for live imaging, reveals subcellular mTOR signaling and dysfunctions. BMC Biol 2020; 18:81. [PMID: 32620110 PMCID: PMC7334845 DOI: 10.1186/s12915-020-00790-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/06/2020] [Indexed: 11/24/2022] Open
Abstract
Background mTOR signaling is an essential nutrient and energetic sensing pathway. Here we describe AIMTOR, a sensitive genetically encoded BRET (Bioluminescent Resonance Energy Transfer) biosensor to study mTOR activity in living cells. Results As a proof of principle, we show in both cell lines and primary cell cultures that AIMTOR BRET intensities are modified by mTOR activity changes induced by specific inhibitors and activators of mTORC1 including amino acids and insulin. We further engineered several versions of AIMTOR enabling subcellular-specific assessment of mTOR activities. We then used AIMTOR to decipher mTOR signaling in physio-pathological conditions. First, we show that mTORC1 activity increases during muscle cell differentiation and in response to leucine stimulation in different subcellular compartments such as the cytosol and at the surface of the lysosome, the nucleus, and near the mitochondria. Second, in hippocampal neurons, we found that the enhancement of neuronal activity increases mTOR signaling. AIMTOR further reveals mTOR-signaling dysfunctions in neurons from mouse models of autism spectrum disorder. Conclusions Altogether, our results demonstrate that AIMTOR is a sensitive and specific tool to investigate mTOR-signaling dynamics in living cells and phenotype mTORopathies.
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Affiliation(s)
| | - Enora Moutin
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Lionel A Tintignac
- University Hospital Basel, Department of Biomedecine, Basel, Switzerland
| | | | - Elodie Jublanc
- DMEM, University of Montpellier, INRAE, Montpellier, France
| | - Michael Sinnreich
- University Hospital Basel, Department of Biomedecine, Basel, Switzerland
| | - Yan Chastagnier
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Julien Averous
- Université Clermont Auvergne, INRAE, Unité de Nutrition Humaine, UMR1019, Clermont-Ferrand, France
| | - Pierre Fafournoux
- Université Clermont Auvergne, INRAE, Unité de Nutrition Humaine, UMR1019, Clermont-Ferrand, France
| | - Chiara Verpelli
- Cnr Institute of Neuroscience, Via Vanvitelli, 3220129, Milan, Italy
| | - Tobias Boeckers
- Anatomie und Zellbiologie Universität Ulm, Albert-Einstein Allee 11, Raumnummer 4105, M24, 89081, Ulm, Germany
| | - Gilles Carnac
- Phymedexp, University of Montpellier, CNRS, INSERM, Montpellier, France
| | - Julie Perroy
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France.
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Jin CL, Zhang ZM, Song ZW, Gao CQ, Yan HC, Wang XQ. mTORC1-Mediated Satellite Cell Differentiation Is Required for Lysine-Induced Skeletal Muscle Growth. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:4884-4892. [PMID: 32275833 DOI: 10.1021/acs.jafc.0c01275] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Skeletal muscle is the primary source of protein for humans. However, the mechanisms of skeletal muscle growth, such as nutrition control, remain unknown. Moreover, the function of lysine (Lys) in controling skeletal muscle growth has gradually demonstrated that Lys is not only substantial for protein synthesis but also a signaling molecule for satellite cell (SC) activation. In the current work, the number of differentiated SCs in the longissimus thoracis muscle and the fusion index of SCs were both governed by Lys supplementation. Meanwhile, the myogenic regulatory factors and the mammalian target of rapamycin complex 1 (mTORC1) pathway showed the same tendencies of changes as the differentiation of SCs. After Lys was resupplemented with rapamycin, the mTORC1 pathway was inhibited and the differentiation ability of SCs was suppressed. Collectively, the results showed that the mTORC1-pathway-mediated SC differentiation was required for Lys-promoted skeletal muscle growth.
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Affiliation(s)
- Cheng-Long Jin
- College of Animal Science, South China Agricultural University/Guangdong Provincial Key Laboratory of Animal Nutrition Control/National Engineering Research Center for Breeding Swine Industry, Guangzhou, Guangdong 510642, People's Republic of China
| | - Zong-Ming Zhang
- College of Animal Science, South China Agricultural University/Guangdong Provincial Key Laboratory of Animal Nutrition Control/National Engineering Research Center for Breeding Swine Industry, Guangzhou, Guangdong 510642, People's Republic of China
| | - Zhi-Wen Song
- College of Animal Science, South China Agricultural University/Guangdong Provincial Key Laboratory of Animal Nutrition Control/National Engineering Research Center for Breeding Swine Industry, Guangzhou, Guangdong 510642, People's Republic of China
| | - Chun-Qi Gao
- College of Animal Science, South China Agricultural University/Guangdong Provincial Key Laboratory of Animal Nutrition Control/National Engineering Research Center for Breeding Swine Industry, Guangzhou, Guangdong 510642, People's Republic of China
| | - Hui-Chao Yan
- College of Animal Science, South China Agricultural University/Guangdong Provincial Key Laboratory of Animal Nutrition Control/National Engineering Research Center for Breeding Swine Industry, Guangzhou, Guangdong 510642, People's Republic of China
| | - Xiu-Qi Wang
- College of Animal Science, South China Agricultural University/Guangdong Provincial Key Laboratory of Animal Nutrition Control/National Engineering Research Center for Breeding Swine Industry, Guangzhou, Guangdong 510642, People's Republic of China
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Dadon-Freiberg M, Chapnik N, Froy O. REV-ERBα activates the mTOR signalling pathway and promotes myotubes differentiation. Biol Cell 2020; 112:213-221. [PMID: 32306421 DOI: 10.1111/boc.201900091] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 04/13/2020] [Indexed: 12/29/2022]
Abstract
BACKGROUND INFORMATION Mammalian target of rapamycin (mTOR) complex 1 (mTORC1) is a master regulator of cell and whole-body energy homoeostasis. REV-ERBα is a nuclear receptor that plays an important role in metabolism. While mTORC1 activation is necessary for muscle differentiation, the role of REV-ERBα is less clear. RESULTS We studied the effect of REV-ERBα overexpression and silencing as well as mTORC1 activation and inhibition on the differentiation of C2C12 myoblasts to myotubes. mTOR, myogenin and REV-ERBα were induced during differentiation of myoblasts into myotubes. REV-ERBα was found to activate mTORC1 during the differentiation process even in the absence of the differentiation medium. This activation was presumably through the downregulation of the expression of TSC1, an mTORC1 inhibitor. CONCLUSION Herein we show that REV-ERBα promotes myoblasts differentiation via the activation of the mTORC1 signalling pathway. SIGNIFICANCE REV-ERBα modulation can activate mTORC1 signalling and promote myoblasts differentiation.
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Affiliation(s)
- Maayan Dadon-Freiberg
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Nava Chapnik
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
| | - Oren Froy
- Institute of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
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Ham AS, Chojnowska K, Tintignac LA, Lin S, Schmidt A, Ham DJ, Sinnreich M, Rüegg MA. mTORC1 signalling is not essential for the maintenance of muscle mass and function in adult sedentary mice. J Cachexia Sarcopenia Muscle 2020; 11:259-273. [PMID: 31697050 PMCID: PMC7015237 DOI: 10.1002/jcsm.12505] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 09/09/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The balance between protein synthesis and degradation (proteostasis) is a determining factor for muscle size and function. Signalling via the mammalian target of rapamycin complex 1 (mTORC1) regulates proteostasis in skeletal muscle by affecting protein synthesis and autophagosomal protein degradation. Indeed, genetic inactivation of mTORC1 in developing and growing muscle causes atrophy resulting in a lethal myopathy. However, systemic dampening of mTORC1 signalling by its allosteric inhibitor rapamycin is beneficial at the organismal level and increases lifespan. Whether the beneficial effect of rapamycin comes at the expense of muscle mass and function is yet to be established. METHODS We conditionally ablated the gene coding for the mTORC1-essential component raptor in muscle fibres of adult mice [inducible raptor muscle-specific knockout (iRAmKO)]. We performed detailed phenotypic and biochemical analyses of iRAmKO mice and compared them with muscle-specific raptor knockout (RAmKO) mice, which lack raptor in developing muscle fibres. We also used polysome profiling and proteomics to assess protein translation and associated signalling in skeletal muscle of iRAmKO mice. RESULTS Analysis at different time points reveal that, as in RAmKO mice, the proportion of oxidative fibres decreases, but slow-type fibres increase in iRAmKO mice. Nevertheless, no significant decrease in body and muscle mass or muscle fibre area was detected up to 5 months post-raptor depletion. Similarly, ex vivo muscle force was not significantly reduced in iRAmKO mice. Despite stable muscle size and function, inducible raptor depletion significantly reduced the expression of key components of the translation machinery and overall translation rates. CONCLUSIONS Raptor depletion and hence complete inhibition of mTORC1 signalling in fully grown muscle leads to metabolic and morphological changes without inducing muscle atrophy even after 5 months. Together, our data indicate that maintenance of muscle size does not require mTORC1 signalling, suggesting that rapamycin treatment is unlikely to negatively affect muscle mass and function.
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Affiliation(s)
| | | | - Lionel A Tintignac
- Department of Biomedicine, Pharmazentrum, University of Basel, Basel, Switzerland
| | - Shuo Lin
- Biozentrum, University of Basel, Basel, Switzerland
| | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Daniel J Ham
- Biozentrum, University of Basel, Basel, Switzerland
| | - Michael Sinnreich
- Department of Biomedicine, Pharmazentrum, University of Basel, Basel, Switzerland
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Effect of dietary threonine on growth performance and muscle growth, protein synthesis and antioxidant-related signalling pathways of hybrid catfish Pelteobagrus vachelli♀ × Leiocassis longirostris♂. Br J Nutr 2019; 123:121-134. [PMID: 31637992 DOI: 10.1017/s0007114519002599] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The experiment was conducted to investigate the effects of dietary threonine (Thr) on growth performance and muscle growth, protein synthesis and antioxidant-related signalling pathways of hybrid catfish Pelteobagrus vachelli♀ × Leiocassis longirostris♂. A total of 1200 fish (14·19 (se 0·13) g) were randomly distributed into six groups with four replicates each, fed six diets with graded level of Thr (9·5, 11·5, 13·5, 15·4, 17·4 and 19·3 g/kg diets) for 56 d. Results showed (P < 0·05) that dietary Thr (1) increased percentage weight gain, specific growth rate, feed efficiency and protein efficiency ratio; (2) up-regulated growth hormone (GH), insulin-like growth factor 1 (IGF-1), proliferating cell nuclear antigen, myogenic regulation factors (MyoD, Myf5, MyoG and Mrf4) and myosin heavy chain (MyHC) mRNA levels; (3) increased muscle protein content via regulating the protein kinase B/target of rapamycin signalling pathway and (4) decreased malondialdehyde and protein carbonyl contents, increased catalase, glutathione-S-transferase, glutathione reductase and GSH activities, up-regulated mRNA levels of antioxidant enzymes related to NFE2-related factor 2 and γ-glutamylcysteine ligase catalytic subunit. These results suggest that Thr has a potential role to improve muscle growth and protein synthesis, which might be due to the regulation of GH-IGF system, muscle growth-related gene, antioxidative capacity and protein synthesis-related signalling pathways. Based on the quadratic regression analysis of specific growth rate, the Thr requirement of hybrid catfish (14·19-25·77 g) was estimated to be 13·77 g/kg of the diet (33·40 g/kg of dietary protein).
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Purohit G, Dhawan J. Adult Muscle Stem Cells: Exploring the Links Between Systemic and Cellular Metabolism. Front Cell Dev Biol 2019; 7:312. [PMID: 31921837 PMCID: PMC6915107 DOI: 10.3389/fcell.2019.00312] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 11/15/2019] [Indexed: 12/13/2022] Open
Abstract
Emerging evidence suggests that metabolites are important regulators of skeletal muscle stem cell (MuSC) function and fate. While highly proliferative in early life, MuSCs reside in adult skeletal muscle tissue in a quiescent and metabolically depressed state, but are critical for the homeostatic maintenance and regenerative response of the tissue to damage. It is well established that metabolic activity in MuSC changes with their functional activation, but the spatiotemporal links between physiological metabolism and stem cell metabolism require explicit delineation. The quiescent MuSC is defined by a specific metabolic state, which is controlled by intrinsic and extrinsic factors during physiological and pathological tissue dynamics. However, the extent of tissue and organismal level changes driven by alteration in metabolic state of quiescent MuSC is currently not well defined. In addition to their role as biosynthetic precursors and signaling molecules, metabolites are key regulators of epigenetic mechanisms. Emerging evidence points to metabolic control of epigenetic mechanisms in MuSC and their impact on muscle regenerative capacity. In this review, we explore the links between cell-intrinsic, tissue level, and systemic metabolic state in the context of MuSC metabolic state, quiescence, and tissue homeostasis to highlight unanswered questions.
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Affiliation(s)
- Gunjan Purohit
- Centre for Cellular and Molecular Biology, Hyderabad, India
| | - Jyotsna Dhawan
- Centre for Cellular and Molecular Biology, Hyderabad, India
- Institute for Stem Cell Science and Regenerative Medicine, Bengaluru, India
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Rion N, Castets P, Lin S, Enderle L, Reinhard JR, Rüegg MA. mTORC2 affects the maintenance of the muscle stem cell pool. Skelet Muscle 2019; 9:30. [PMID: 31791403 PMCID: PMC6886171 DOI: 10.1186/s13395-019-0217-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 10/23/2019] [Indexed: 01/15/2023] Open
Abstract
Background The mammalian target of rapamycin complex 2 (mTORC2), containing the essential protein rictor, regulates cellular metabolism and cytoskeletal organization by phosphorylating protein kinases, such as PKB/Akt, PKC, and SGK. Inactivation of mTORC2 signaling in adult skeletal muscle affects its metabolism, but not muscle morphology and function. However, the role of mTORC2 in adult muscle stem cells (MuSCs) has not been investigated. Method Using histological, biochemical, and molecular biological methods, we characterized the muscle phenotype of mice depleted for rictor in the Myf5-lineage (RImyfKO) and of mice depleted for rictor in skeletal muscle fibers (RImKO). The proliferative and myogenic potential of MuSCs was analyzed upon cardiotoxin-induced injury in vivo and in isolated myofibers in vitro. Results Skeletal muscle of young and 14-month-old RImyfKO mice appeared normal in composition and function. MuSCs from young RImyfKO mice exhibited a similar capacity to proliferate, differentiate, and fuse as controls. In contrast, the number of MuSCs was lower in young RImyfKO mice than in controls after two consecutive rounds of cardiotoxin-induced muscle regeneration. Similarly, the number of MuSCs in RImyfKO mice decreased with age, which correlated with a decline in the regenerative capacity of mutant muscle. Interestingly, reduction in the number of MuSCs was also observed in 14-month-old RImKO muscle. Conclusions Our study shows that mTORC2 signaling is dispensable for myofiber formation, but contributes to the homeostasis of MuSCs. Loss of mTORC2 does not affect their myogenic function, but impairs the replenishment of MuSCs after repeated injuries and their maintenance during aging. These results point to an important role of mTORC2 signaling in MuSC for muscle homeostasis.
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Affiliation(s)
- Nathalie Rion
- Biozentrum, University of Basel, CH-4056, Basel, Switzerland
| | - Perrine Castets
- Biozentrum, University of Basel, CH-4056, Basel, Switzerland.,Department PHYM, Centre Médical Universitaire de Genève, Geneva, Switzerland
| | - Shuo Lin
- Biozentrum, University of Basel, CH-4056, Basel, Switzerland
| | - Leonie Enderle
- Biozentrum, University of Basel, CH-4056, Basel, Switzerland.,Toronto Recombinant Antibody Centre/The Donnelly Centre, University of Toronto, M5G 1 L6, Toronto, ON, Canada
| | | | - Markus A Rüegg
- Biozentrum, University of Basel, CH-4056, Basel, Switzerland.
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Ma J, Ren C, Yang H, Zhao J, Wang F, Wan Y. The Expression Pattern of p32 in Sheep Muscle and Its Role in Differentiation, Cell Proliferation, and Apoptosis of Myoblasts. Int J Mol Sci 2019; 20:ijms20205161. [PMID: 31635221 PMCID: PMC6829534 DOI: 10.3390/ijms20205161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 09/30/2019] [Indexed: 12/21/2022] Open
Abstract
The complement 1q binding protein C (C1QBP), also known as p32, is highly expressed in rapidly growing tissues and plays a crucial role in cell proliferation and apoptosis. However, there are no data interpreting its mechanisms in muscle development. To investigate the role of p32 in sheep muscle development, an 856 bp cDNA fragment of p32 containing an 837 bp coding sequence that encodes 278 amino acids was analyzed. We then revealed that the expression of p32 in the longissimus and quadricep muscles of fetal sheep was more significantly up-regulated than expression at other developmental stages. Furthermore, we found that the expression of p32 was increased during myoblasts differentiation in vitro. Additionally, the knockdown of p32 in sheep myoblasts effectively inhibited myoblast differentiation, proliferation, and promoted cell apoptosis in vitro. The interference of p32 also changed the energy metabolism from Oxidative Phosphorylation (OXPHOS) to glycolysis and activated AMP-activated protein kinase (AMPK) phosphorylation in sheep myoblasts in vitro. Taken together, our data suggest that p32 plays a vital role in the development of sheep muscle and provides a potential direction for future research on muscle development and some muscle diseases.
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Affiliation(s)
- Jianyu Ma
- Institute of Sheep and Goat Science; Nanjing Agricultural University, Nanjing 210095, China.
| | - Caifang Ren
- Institute of Sheep and Goat Science; Nanjing Agricultural University, Nanjing 210095, China.
| | - Hua Yang
- Institute of Sheep and Goat Science; Nanjing Agricultural University, Nanjing 210095, China.
| | - Jie Zhao
- Institute of Sheep and Goat Science; Nanjing Agricultural University, Nanjing 210095, China.
| | - Feng Wang
- Institute of Sheep and Goat Science; Nanjing Agricultural University, Nanjing 210095, China.
| | - Yongjie Wan
- Institute of Sheep and Goat Science; Nanjing Agricultural University, Nanjing 210095, China.
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Maiole F, Giachero S, Fossati SM, Rocchi A, Zullo L. mTOR as a Marker of Exercise and Fatigue in Octopus vulgaris Arm. Front Physiol 2019; 10:1161. [PMID: 31572212 PMCID: PMC6749024 DOI: 10.3389/fphys.2019.01161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/28/2019] [Indexed: 01/07/2023] Open
Abstract
Cephalopods are highly evolved marine invertebrates that colonized almost all the oceans of the world at all depths. This imposed the occurrence of several modifications of their brain and body whose muscle component represents the major constituent. Hence, studying their muscle physiology may give important hints in the context of animal biology and environmental adaptability. One major pathway involved in muscle metabolism in vertebrates is the evolutionary conserved mTOR-signaling cascade; however, its role in cephalopods has never been elucidated. mTOR is regulating cell growth and homeostasis in response to a wide range of cues such as nutrient availability, body temperature and locomotion. It forms two functionally heteromeric complexes, mTORC1 and mTORC2. mTORC1 regulates protein synthesis and degradation and, in skeletal muscles, its activation upon exercise induces muscle growth. In this work, we characterized Octopus vulgaris mTOR full sequence and functional domains; we found a high level of homology with vertebrates’ mTOR and the conservation of Ser2448 phosphorylation site required for mTORC1 activation. We then designed and tested an in vitro protocol of resistance exercise (RE) inducing fatigue in arm samples. We showed that, upon the establishment of fatigue, a transient increase in mTORC1 phosphorylation reaching a pick 30 min after exercise was induced. Our data indicate the activation of mTORC1 pathway in exercise paradigm and possibly in the regulation of energy homeostasis in octopus and suggest that mTORC1 activity can be used to monitor animal response to changes in physiological and ecological conditions and, more in general, the animal welfare.
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Affiliation(s)
- Federica Maiole
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy.,Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Sarah Giachero
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy.,Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Sara Maria Fossati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Anna Rocchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy.,IRCSS Ospedale Policlinico San Martino, Genoa, Italy
| | - Letizia Zullo
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy.,IRCSS Ospedale Policlinico San Martino, Genoa, Italy
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Wei X, Luo L, Chen J. Roles of mTOR Signaling in Tissue Regeneration. Cells 2019; 8:cells8091075. [PMID: 31547370 PMCID: PMC6769890 DOI: 10.3390/cells8091075] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 09/06/2019] [Accepted: 09/07/2019] [Indexed: 12/11/2022] Open
Abstract
The mammalian target of rapamycin (mTOR), is a serine/threonine protein kinase and belongs to the phosphatidylinositol 3-kinase (PI3K)-related kinase (PIKK) family. mTOR interacts with other subunits to form two distinct complexes, mTORC1 and mTORC2. mTORC1 coordinates cell growth and metabolism in response to environmental input, including growth factors, amino acid, energy and stress. mTORC2 mainly controls cell survival and migration through phosphorylating glucocorticoid-regulated kinase (SGK), protein kinase B (Akt), and protein kinase C (PKC) kinase families. The dysregulation of mTOR is involved in human diseases including cancer, cardiovascular diseases, neurodegenerative diseases, and epilepsy. Tissue damage caused by trauma, diseases or aging disrupt the tissue functions. Tissue regeneration after injuries is of significance for recovering the tissue homeostasis and functions. Mammals have very limited regenerative capacity in multiple tissues and organs, such as the heart and central nervous system (CNS). Thereby, understanding the mechanisms underlying tissue regeneration is crucial for tissue repair and regenerative medicine. mTOR is activated in multiple tissue injuries. In this review, we summarize the roles of mTOR signaling in tissue regeneration such as neurons, muscles, the liver and the intestine.
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Affiliation(s)
- Xiangyong Wei
- Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China.
| | - Lingfei Luo
- Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China.
| | - Jinzi Chen
- Laboratory of Molecular Developmental Biology, School of Life Sciences, Southwest University, Beibei, Chongqing 400715, China.
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The people behind the papers - Nathalie Rion and Markus Rüegg. Development 2019; 146:146/7/dev178491. [PMID: 30962324 DOI: 10.1242/dev.178491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In development and during regeneration in adults, muscle fibres develop from muscle progenitor cells, and the proliferation, differentiation and fusion of these progenitors needs to be tightly controlled and co-ordinated. A new paper in Development studies the role of the mTOR protein in this process using genetic deletions that target either of the two protein complexes mTOR functions in. We caught up with lead author Nathalie Rion and her supervisor Markus Rüegg, Professor of Neurobiology at Biozentrum, University of Basel, to find out more about the work.
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