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Navarro-Martínez A, Vicente-García C, Carvajal JJ. NMJ-related diseases beyond the congenital myasthenic syndromes. Front Cell Dev Biol 2023; 11:1216726. [PMID: 37601107 PMCID: PMC10436495 DOI: 10.3389/fcell.2023.1216726] [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: 05/04/2023] [Accepted: 07/21/2023] [Indexed: 08/22/2023] Open
Abstract
Neuromuscular junctions (NMJs) are a special type of chemical synapse that transmits electrical stimuli from motor neurons (MNs) to their innervating skeletal muscle to induce a motor response. They are an ideal model for the study of synapses, given their manageable size and easy accessibility. Alterations in their morphology or function lead to neuromuscular disorders, such as the congenital myasthenic syndromes, which are caused by mutations in proteins located in the NMJ. In this review, we highlight novel potential candidate genes that may cause or modify NMJs-related pathologies in humans by exploring the phenotypes of hundreds of mouse models available in the literature. We also underscore the fact that NMJs may differ between species, muscles or even sexes. Hence the importance of choosing a good model organism for the study of NMJ-related diseases: only taking into account the specific features of the mammalian NMJ, experimental results would be efficiently translated to the clinic.
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Affiliation(s)
| | - Cristina Vicente-García
- Centro Andaluz de Biología del Desarrollo, CSIC-UPO-JA, Universidad Pablo de Olavide, Sevilla, Spain
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2
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Guo J, Ye X, Zhao Y, Huang D, Wu Q, Ihsan A, Wang X. NRF-2α and mitophagy underlie enhanced mitochondrial functions and biogenesis induced by T-2 toxin in GH3 cells. Food Chem Toxicol 2023; 174:113687. [PMID: 36863559 DOI: 10.1016/j.fct.2023.113687] [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: 11/15/2022] [Revised: 02/16/2023] [Accepted: 02/20/2023] [Indexed: 03/04/2023]
Abstract
T-2 toxin is a natural contaminant in grain cereals produced by species of Fusarium. Studies indicate that T-2 toxin can positively affect mitochondrial function, but the underlying mechanism is unclear. In this study, we examined the role of nuclear respiratory factor 2α (NRF-2α) in T-2 toxin-activated mitochondrial biogenesis and the direct target genes of NRF-2α. Furthermore, we investigated T-2 toxin-induced autophagy and mitophagy, and the role of mitophagy in changes in mitochondrial function and apoptosis. It was found that T-2 toxin significantly increased NRF-2α levels and nuclear localization of NRF-2α was induced. NRF-2α deletion significantly increased the production of reactive oxygen species (ROS), abrogated T-2 toxin-induced increases in ATP and mitochondrial complex I activity, and inhibited the mitochondrial DNA copy number. Meanwhile, With chromatin immunoprecipitation sequencing (ChIP-Seq), various novel NRF-2α target genes were identified, such as mitochondrial iron-sulphur subunits (Ndufs 3,7) and mitochondrial transcription factors (Tfam, Tfb1m, and Tfb2m). Some target genes were also involved in mitochondrial fusion and fission (Drp1), mitochondrial translation (Yars2) and splicing (Ddx55), and mitophagy. Further studies showed that T-2 toxin induced Atg5 dependent autophagy and Atg5/PINK1-dependent mitophagy. In addition, mitophagy defects increase ROS production, inhibit ATP levels and the expression of genes related to mitochondrial dynamics, and promote apoptosis in the presence of T-2 toxins. Altogether, these results suggest that NRF-2α plays a critical role in promoting mitochondrial function and biogenesis through regulation of mitochondrial genes, and, interestingly, mitophagy caused by T-2 toxin positively affected mitochondrial function and protected cell survival against T-2 toxin.
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Affiliation(s)
- Jingchao Guo
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Xiaochun Ye
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Yongxia Zhao
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Deyu Huang
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Qinghua Wu
- College of Life Science, Institute of Biomedicine, Yangtze University, Jingzhou, 434025, China
| | - Awais Ihsan
- Department of Biosciences, COMSATS University Islamabad, Sahiwal campus, Pakistan
| | - Xu Wang
- National Reference Laboratory of Veterinary Drug Residues (HZAU) and MAO Key Laboratory for Detection of Veterinary Drug Residues, Huazhong Agricultural University, Wuhan, Hubei, 430070, China; MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
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3
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Qi Z, Wang S, Xuan A, Gu X, Deng J, Huang C, Zhang L, Yin X. MiR-142a-3p: A novel ACh receptor transcriptional regulator in association with peripheral nerve injury. MOLECULAR THERAPY. NUCLEIC ACIDS 2022; 30:325-336. [PMID: 36381585 PMCID: PMC9633872 DOI: 10.1016/j.omtn.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 10/12/2022] [Indexed: 12/15/2022]
Abstract
Long-term denervation leads to the disintegration of nicotinic acetylcholine receptor (nAChR) located at the endplate structure, which translates to deficits in functional activation despite nerve repair. Because of a lack of effective measures to protect AChR expression, we explored the effect of alterations in muscular miR-142a-3p on nAChR. In this study, we constructed a model of miR-142a-3p knockdown by transfecting a miR-142a-3p inhibitor short hairpin RNA (shRNA) into C2C12 myotubes, and we injected this miR-142a-3p inhibitor shRNA into the tibialis anterior (TA) muscle in uninjured mice and in denervated mice by transecting the sciatic nerve. Our results showed that miR-142a-3p knockdown led to an increased number and area of AChR clusters in myotubes in vitro and larger neuromuscular endplates in adult mice. Furthermore, miR-142a-3p knockdown delayed the disintegration of motor endplates after denervation. Last, upon miR-142a-3p knockdown in uninjured and denervated mice, we observed an increase in the mRNA levels of five AChR subunits as well as mRNAs of genes implicated in AChR transcription and AChR clustering. Together, these results suggest that miR-142a-3p may be a potential target for therapeutic intervention to prevent motor endplate degradation following peripheral nerve injury.
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Affiliation(s)
- Zhidan Qi
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Shen Wang
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Ang Xuan
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China,MoE Key Laboratory for Biomedical Photonics, School of Engineering Sciences, Huazhong University of Science and Technology, Wuhan, China
| | - Xinyi Gu
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Jin Deng
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Chen Huang
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China
| | - Lei Zhang
- Electron Microscopy Analysis Laboratory, Medical and Health Analysis Center, Peking University, Beijing, China,Department of Biophysics, School of Basic Medical Sciences, Peking University, Beijing, China
| | - Xiaofeng Yin
- Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China,Pizhou People’s Hospital, Jiangsu, China,Corresponding author Xiaofeng Yin, Department of Orthopedics and Trauma, Peking University People’s Hospital, Beijing, China.
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4
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Ng SY, Ljubicic V. Recent insights into neuromuscular junction biology in Duchenne muscular dystrophy: Impacts, challenges, and opportunities. EBioMedicine 2020; 61:103032. [PMID: 33039707 PMCID: PMC7648118 DOI: 10.1016/j.ebiom.2020.103032] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/28/2020] [Accepted: 09/11/2020] [Indexed: 12/13/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most common and relentless form of muscular dystrophy. The pleiotropic effects of dystrophin deficiency include remarkable impacts on neuromuscular junction (NMJ) structure and function. Some of these alterations contribute to the severe muscle wasting and weakness that distinguish DMD, while others attempt to compensate for them. Experimental approaches that correct NMJ biology in pre-clinical models of DMD attenuate disease progression and improve functional outcomes, which suggests that targeting the NMJ may be an effective therapeutic strategy for DMD patients. The objectives of this review are to 1) survey the distinctions in NMJ structure, function, and gene expression in the dystrophic context as compared to the healthy condition, and 2) summarize the efforts, opportunities and challenges to correct NMJ biology in DMD. This information will expand our basic understanding of neuromuscular biology and may be useful for designing novel NMJ-targeted drug or behavioural strategies to mitigate the dystrophic pathology and other disorders of the neuromuscular system.
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Affiliation(s)
- Sean Y Ng
- Department of Kinesiology, McMaster University, Hamilton L8S 4L8, Ontario, Canada
| | - Vladimir Ljubicic
- Department of Kinesiology, McMaster University, Hamilton L8S 4L8, Ontario, Canada.
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5
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A Role of Lamin A/C in Preventing Neuromuscular Junction Decline in Mice. J Neurosci 2020; 40:7203-7215. [PMID: 32817327 DOI: 10.1523/jneurosci.0443-20.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 08/10/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022] Open
Abstract
During aging, skeletal muscles become atrophic and lose contractile force. Aging can also impact the neuromuscular junction (NMJ), a synapse that transmits signals from motoneurons to muscle fibers to control muscle contraction. However, in contrast to muscle aging that has been studied extensively, less is known about the molecular mechanisms of NMJ aging although its structure and function are impaired in aged animals. To this end, we performed RNA sequencing (RNA-seq) analysis to identify genes whose expression in synapse-rich region is altered. Gene ontology (GO) analysis highlighted genes relating to nuclear structure or function. In particular, lamin A/C, an intermediate filament protein critical for the interphase nuclear architecture, was reduced. Remarkably, mutation of lamin A/C in muscles or motoneurons had no effect on NMJ formation in either sex of mice, but the muscle mutation caused progressive denervation, acetylcholine receptor (AChR) cluster fragmentation, and neuromuscular dysfunction. Interestingly, rapsyn, a protein critical to AChR clustering, was reduced in mutant muscle cells; and expressing rapsyn in muscles attenuated NMJ deficits of HSA-Lmna-/- mice. These results reveal a role of lamin A/C in NMJ maintenance and suggest that nuclear dysfunction or deficiency may contribute to NMJ deficits in aged muscles.SIGNIFICANCE STATEMENT This study provides evidence that lamin A/C, a scaffolding component of the nuclear envelope, is critical to maintaining the NMJ in mice. Its muscle-specific mutation led to progressive NMJ degeneration in vivo We showed that the mutation reduced the level of rapsyn, a protein necessary for acetylcholine receptor (AChR) clustering; and expression of rapsyn in muscles attenuated NMJ deficits of HSA-Lmna-/- mice. These results reveal a role of lamin A/C in NMJ maintenance and suggest that nuclear dysfunction or deficiency may contribute to NMJ deficits in aged muscles.
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Belotti E, Schaeffer L. Regulation of Gene expression at the neuromuscular Junction. Neurosci Lett 2020; 735:135163. [PMID: 32553805 DOI: 10.1016/j.neulet.2020.135163] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 01/08/2023]
Abstract
Gene expression in skeletal muscle is profoundly changed upon innervation. 50 years of research on the neuromuscular system have greatly increased our understanding of the mechanisms underlying these changes. By controlling the expression and the activity of key transcription factors, nerve-evoked electrical activity in the muscle fiber positively and negatively regulates the expression of hundreds of genes. Innervation also compartmentalizes gene expression into synaptic and extra-synaptic regions of muscle fibers. In addition, electrically-evoked, release of several factors (e.g. Agrin, Neuregulin, Wnt ligands) induce the clustering of synaptic proteins and of a few muscle nuclei. The sub-synaptic nuclei acquire a particular chromatin organization and develop a specific gene expression program dedicated to building and maintaining a functional neuromuscular synapse. Deciphering synapse-specific, transcriptional regulation started with the identification of the N-box, a six base pair element present in the promoters of the acetylcholine δ and ε subunits. Most genes with synapse-specific expression turned out to contain at least one N-box in their promoters. The N-box is a response element for the synaptic signals Agrin and Neuregulins as well as a binding site for transcription factors of the Ets family. The Ets transcription factors GABP and Erm are implicated in the activation of post-synaptic genes via the N-box. In muscle fibers, Erm expression is restricted to the NMJ whereas GABP is expressed in all muscle nuclei but phosphorylated and activated by the JNK and ERK signaling pathways in response to Agrin and Neuregulins. Post-synaptic gene expression also correlates with chromatin modifications at the genomic level as evidenced by the strong enrichment of decondensed chromatin and acetylated histones in sub-synaptic nuclei. Here we discuss these transcriptional pathways for synaptic specialization at NMJs.
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Affiliation(s)
- Edwige Belotti
- INMG, Inserm U1217, CNRS UMR5310, Université Lyon 1, Université De Lyon, Lyon, France
| | - Laurent Schaeffer
- INMG, Inserm U1217, CNRS UMR5310, Université Lyon 1, Université De Lyon, Lyon, France; Centre De Biotechnologie Cellulaire, Hospices Civils De Lyon, Lyon, France.
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Pravata VM, Omelková M, Stavridis MP, Desbiens CM, Stephen HM, Lefeber DJ, Gecz J, Gundogdu M, Õunap K, Joss S, Schwartz CE, Wells L, van Aalten DMF. An intellectual disability syndrome with single-nucleotide variants in O-GlcNAc transferase. Eur J Hum Genet 2020; 28:706-714. [PMID: 32080367 PMCID: PMC7253464 DOI: 10.1038/s41431-020-0589-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 12/30/2019] [Accepted: 02/04/2020] [Indexed: 01/05/2023] Open
Abstract
Intellectual disability (ID) is a neurodevelopmental condition that affects ~1% of the world population. In total 5-10% of ID cases are due to variants in genes located on the X chromosome. Recently, variants in OGT have been shown to co-segregate with X-linked intellectual disability (XLID) in multiple families. OGT encodes O-GlcNAc transferase (OGT), an essential enzyme that catalyses O-linked glycosylation with β-N-acetylglucosamine (O-GlcNAc) on serine/threonine residues of thousands of nuclear and cytosolic proteins. In this review, we compile the work from the last few years that clearly delineates a new syndromic form of ID, which we propose to classify as a novel Congenital Disorder of Glycosylation (OGT-CDG). We discuss potential hypotheses for the underpinning molecular mechanism(s) that provide impetus for future research studies geared towards informed interventions.
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Affiliation(s)
- Veronica M. Pravata
- 0000 0004 0397 2876grid.8241.fDivision of Gene Regulation and Expression and School of Life Sciences, University of Dundee, Dundee, UK
| | - Michaela Omelková
- 0000 0004 0397 2876grid.8241.fDivision of Gene Regulation and Expression and School of Life Sciences, University of Dundee, Dundee, UK
| | - Marios P. Stavridis
- 0000 0004 0397 2876grid.8241.fDivision of Cell and Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
| | - Chelsea M. Desbiens
- 0000 0004 1936 738Xgrid.213876.9Department of Biochemistry and Molecular Biology and Chemistry, Complex Carbohydrate Research Center, University of Georgia, Athens, GA USA
| | - Hannah M. Stephen
- 0000 0004 1936 738Xgrid.213876.9Department of Biochemistry and Molecular Biology and Chemistry, Complex Carbohydrate Research Center, University of Georgia, Athens, GA USA
| | - Dirk J. Lefeber
- 0000 0004 0444 9382grid.10417.33Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, 6500 HB Nijmegen, The Netherlands
| | - Jozef Gecz
- 0000 0004 1936 7304grid.1010.0Adelaide Medical School and the Robinson Research Institute, The University of Adelaide, Adelaide, SA Australia
| | - Mehmet Gundogdu
- 0000 0001 2193 314Xgrid.8756.cInstitute of Molecular Cell and System Biology, University of Glasgow, Glasgow, UK
| | - Katrin Õunap
- 0000 0001 0585 7044grid.412269.aDepartment of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia ,0000 0001 0943 7661grid.10939.32Department of Clinical Genetics, Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Shelagh Joss
- West of Scotland Genetic Service, Queen Elizabeth University Hospital, Glasgow, UK
| | - Charles E. Schwartz
- 0000 0000 8571 0933grid.418307.9Greenwood Genetic Center, Greenwood, SC 29646 USA
| | - Lance Wells
- 0000 0004 1936 738Xgrid.213876.9Department of Biochemistry and Molecular Biology and Chemistry, Complex Carbohydrate Research Center, University of Georgia, Athens, GA USA
| | - Daan M. F. van Aalten
- 0000 0004 0397 2876grid.8241.fDivision of Gene Regulation and Expression and School of Life Sciences, University of Dundee, Dundee, UK ,0000 0001 0379 7164grid.216417.7Institute of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, China
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8
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Pravata VM, Muha V, Gundogdu M, Ferenbach AT, Kakade PS, Vandadi V, Wilmes AC, Borodkin VS, Joss S, Stavridis MP, van Aalten DMF. Catalytic deficiency of O-GlcNAc transferase leads to X-linked intellectual disability. Proc Natl Acad Sci U S A 2019; 116:14961-14970. [PMID: 31296563 PMCID: PMC6660750 DOI: 10.1073/pnas.1900065116] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
O-GlcNAc transferase (OGT) is an X-linked gene product that is essential for normal development of the vertebrate embryo. It catalyses the O-GlcNAc posttranslational modification of nucleocytoplasmic proteins and proteolytic maturation of the transcriptional coregulator Host cell factor 1 (HCF1). Recent studies have suggested that conservative missense mutations distal to the OGT catalytic domain lead to X-linked intellectual disability in boys, but it is not clear if this is through changes in the O-GlcNAc proteome, loss of protein-protein interactions, or misprocessing of HCF1. Here, we report an OGT catalytic domain missense mutation in monozygotic female twins (c. X:70779215 T > A, p. N567K) with intellectual disability that allows dissection of these effects. The patients show limited IQ with developmental delay and skewed X-inactivation. Molecular analyses revealed decreased OGT stability and disruption of the substrate binding site, resulting in loss of catalytic activity. Editing this mutation into the Drosophila genome results in global changes in the O-GlcNAc proteome, while in mouse embryonic stem cells it leads to loss of O-GlcNAcase and delayed differentiation down the neuronal lineage. These data imply that catalytic deficiency of OGT could contribute to X-linked intellectual disability.
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Affiliation(s)
- Veronica M Pravata
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom
| | - Villo Muha
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom
| | - Mehmet Gundogdu
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom
| | - Andrew T Ferenbach
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom
| | - Poonam S Kakade
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom
| | - Vasudha Vandadi
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom
| | - Ariane C Wilmes
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom
| | - Vladimir S Borodkin
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom
| | - Shelagh Joss
- West of Scotland Genetic Service, Queen Elizabeth University Hospital, G51 4TF Glasgow, United Kingdom
| | - Marios P Stavridis
- Division of Cell and Developmental Biology, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom
| | - Daan M F van Aalten
- Division of Gene Regulation and Expression, School of Life Sciences, University of Dundee, DD1 5EH Dundee, United Kingdom;
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Liu C, Dai SK, Sun Z, Wang Z, Liu PP, Du HZ, Yu S, Liu CM, Teng ZQ. GA-binding protein GABPβ1 is required for the proliferation of neural stem/progenitor cells. Stem Cell Res 2019; 39:101501. [PMID: 31344652 DOI: 10.1016/j.scr.2019.101501] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 07/08/2019] [Accepted: 07/12/2019] [Indexed: 01/02/2023] Open
Abstract
GA binding protein (GABP) is a ubiquitously expressed transcription factor that regulates the development of multiple cell types, including osteoblast, hematopoietic stem cells, B cells and T cells. However, so little is known about its biological function in the development of central nervous system. In this report, we show that GABP is highly expressed in neural stem/progenitor cells (NSPCs) and down-regulated in neurons, and that GABPβ1 is required for the proper proliferation of NSPCs. Knockdown of GABPα resulted in an elevated expression level of GABPβ1, and GABPβ1 down-regulation significantly decreased the proliferation of NSPCs, whereas GABPβ2 knockdown did not result in any changes in the proliferation of NSPCs. We observed that there was nearly a 21-fold increase of the GABPβ1S mRNA level in GABPβ1L KO NSPCs compared to WT cells, and knocking down of GABPβ1S in GABPβ1L KO NSPCs could further reduce their proliferation potential. We also found that knockdown of GABPβ1 promoted neuronal and astrocytic differentiation of NSPCs. Finally, we identified dozens of downstream target genes of GABPβ1, which are closely associated with the cell proliferation and differentiation. Collectively, our results suggest that both GABPβ1L and GABPβ1S play an essential role in regulating the proper proliferation and differentiation of NSPCs.
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Affiliation(s)
- Cong Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China; Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Shang-Kun Dai
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China; Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhen Sun
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhuo Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China; Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Pei-Pei Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Hong-Zhen Du
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China
| | - Shuyang Yu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
| | - Chang-Mei Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China; Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China; State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
| | - Zhao-Qian Teng
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China; Savaid Medical School, University of Chinese Academy of Sciences, Beijing 100049, China; Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, China; State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
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10
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Chen Y, Ikeda K, Yoneshiro T, Scaramozza A, Tajima K, Wang Q, Kim K, Shinoda K, Sponton CH, Brown Z, Brack A, Kajimura S. Thermal stress induces glycolytic beige fat formation via a myogenic state. Nature 2019; 565:180-185. [PMID: 30568302 PMCID: PMC6328316 DOI: 10.1038/s41586-018-0801-z] [Citation(s) in RCA: 162] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 11/06/2018] [Indexed: 02/06/2023]
Abstract
Environmental cues profoundly affect cellular plasticity in multicellular organisms. For instance, exercise promotes a glycolytic-to-oxidative fibre-type switch in skeletal muscle, and cold acclimation induces beige adipocyte biogenesis in adipose tissue. However, the molecular mechanisms by which physiological or pathological cues evoke developmental plasticity remain incompletely understood. Here we report a type of beige adipocyte that has a critical role in chronic cold adaptation in the absence of β-adrenergic receptor signalling. This beige fat is distinct from conventional beige fat with respect to developmental origin and regulation, and displays enhanced glucose oxidation. We therefore refer to it as glycolytic beige fat. Mechanistically, we identify GA-binding protein α as a regulator of glycolytic beige adipocyte differentiation through a myogenic intermediate. Our study reveals a non-canonical adaptive mechanism by which thermal stress induces progenitor cell plasticity and recruits a distinct form of thermogenic cell that is required for energy homeostasis and survival.
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Affiliation(s)
- Yong Chen
- UCSF Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Kenji Ikeda
- UCSF Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Takeshi Yoneshiro
- UCSF Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Annarita Scaramozza
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA
| | - Kazuki Tajima
- UCSF Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Qiang Wang
- UCSF Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Kyeongkyu Kim
- UCSF Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Kosaku Shinoda
- UCSF Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
- Department of Medicine and Molecular Pharmacology, Albert Einstein College of Medicine, New York, NY, USA
| | - Carlos Henrique Sponton
- UCSF Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Zachary Brown
- UCSF Diabetes Center, San Francisco, CA, USA
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA
| | - Andrew Brack
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA
- Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA
| | - Shingo Kajimura
- UCSF Diabetes Center, San Francisco, CA, USA.
- Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, San Francisco, CA, USA.
- Department of Cell and Tissue Biology, University of California, San Francisco, CA, USA.
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11
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Luo CT, Osmanbeyoglu HU, Do MH, Bivona MR, Toure A, Kang D, Xie Y, Leslie CS, Li MO. Ets transcription factor GABP controls T cell homeostasis and immunity. Nat Commun 2017; 8:1062. [PMID: 29051483 PMCID: PMC5648787 DOI: 10.1038/s41467-017-01020-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 08/11/2017] [Indexed: 01/08/2023] Open
Abstract
Peripheral T cells are maintained in the absence of vigorous stimuli, and respond to antigenic stimulation by initiating cell cycle progression and functional differentiation. Here we show that depletion of the Ets family transcription factor GA-binding protein (GABP) in T cells impairs T-cell homeostasis. In addition, GABP is critically required for antigen-stimulated T-cell responses in vitro and in vivo. Transcriptome and genome-wide GABP-binding site analyses identify GABP direct targets encoding proteins involved in cellular redox balance and DNA replication, including the Mcm replicative helicases. These findings show that GABP has a nonredundant role in the control of T-cell homeostasis and immunity. T cells need to undergo rapid proliferation in response to antigenic stimulation. Here the authors show that the Ets family transcription factor GABP is required for T-cell homeostasis and response to infection by inducing Mcm3 and Mcm5 expression and enabling S-phase entry.
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Affiliation(s)
- Chong T Luo
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.,Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Hatice U Osmanbeyoglu
- Computational Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Mytrang H Do
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Michael R Bivona
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Ahmed Toure
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Davina Kang
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Yuchen Xie
- Louis V. Gerstner Jr. Graduate School of Biomedical Sciences, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Christina S Leslie
- Computational Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA
| | - Ming O Li
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY, 10065, USA.
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12
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Perdomo-Sabogal A, Nowick K, Piccini I, Sudbrak R, Lehrach H, Yaspo ML, Warnatz HJ, Querfurth R. Human Lineage-Specific Transcriptional Regulation through GA-Binding Protein Transcription Factor Alpha (GABPa). Mol Biol Evol 2016; 33:1231-44. [PMID: 26814189 PMCID: PMC4839217 DOI: 10.1093/molbev/msw007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
A substantial fraction of phenotypic differences between closely related species are likely caused by differences in gene regulation. While this has already been postulated over 30 years ago, only few examples of evolutionary changes in gene regulation have been verified. Here, we identified and investigated binding sites of the transcription factor GA-binding protein alpha (GABPa) aiming to discover cis-regulatory adaptations on the human lineage. By performing chromatin immunoprecipitation-sequencing experiments in a human cell line, we found 11,619 putative GABPa binding sites. Through sequence comparisons of the human GABPa binding regions with orthologous sequences from 34 mammals, we identified substitutions that have resulted in 224 putative human-specific GABPa binding sites. To experimentally assess the transcriptional impact of those substitutions, we selected four promoters for promoter-reporter gene assays using human and African green monkey cells. We compared the activities of wild-type promoters to mutated forms, where we have introduced one or more substitutions to mimic the ancestral state devoid of the GABPa consensus binding sequence. Similarly, we introduced the human-specific substitutions into chimpanzee and macaque promoter backgrounds. Our results demonstrate that the identified substitutions are functional, both in human and nonhuman promoters. In addition, we performed GABPa knock-down experiments and found 1,215 genes as strong candidates for primary targets. Further analyses of our data sets link GABPa to cognitive disorders, diabetes, KRAB zinc finger (KRAB-ZNF), and human-specific genes. Thus, we propose that differences in GABPa binding sites played important roles in the evolution of human-specific phenotypes.
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Affiliation(s)
- Alvaro Perdomo-Sabogal
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, University Leipzig, Leipzig, Germany Paul-Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany
| | - Katja Nowick
- Bioinformatics Group, Department of Computer Science, and Interdisciplinary Center for Bioinformatics, University Leipzig, Leipzig, Germany Paul-Flechsig Institute for Brain Research, University of Leipzig, Leipzig, Germany
| | - Ilaria Piccini
- Institute of Genetics of Heart Diseases (IfGH), Department of Cardiovascular Medicine, University Hospital Münster, 48149 Münster, Germany Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Ralf Sudbrak
- European Centre for Public Heath Genomics, UNU-MERIT, Unsiversity Maastricht,PO Box 616, 6200 MD Maastricht, The Netherlands Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Hans Lehrach
- Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Marie-Laure Yaspo
- Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Hans-Jörg Warnatz
- Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Robert Querfurth
- Department of Vertebrate Genomics, Max Planck Institute for Molecular Genetics, Berlin, Germany
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13
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Tintignac LA, Brenner HR, Rüegg MA. Mechanisms Regulating Neuromuscular Junction Development and Function and Causes of Muscle Wasting. Physiol Rev 2015; 95:809-52. [DOI: 10.1152/physrev.00033.2014] [Citation(s) in RCA: 224] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The neuromuscular junction is the chemical synapse between motor neurons and skeletal muscle fibers. It is designed to reliably convert the action potential from the presynaptic motor neuron into the contraction of the postsynaptic muscle fiber. Diseases that affect the neuromuscular junction may cause failure of this conversion and result in loss of ambulation and respiration. The loss of motor input also causes muscle wasting as muscle mass is constantly adapted to contractile needs by the balancing of protein synthesis and protein degradation. Finally, neuromuscular activity and muscle mass have a major impact on metabolic properties of the organisms. This review discusses the mechanisms involved in the development and maintenance of the neuromuscular junction, the consequences of and the mechanisms involved in its dysfunction, and its role in maintaining muscle mass during aging. As life expectancy is increasing, loss of muscle mass during aging, called sarcopenia, has emerged as a field of high medical need. Interestingly, aging is also accompanied by structural changes at the neuromuscular junction, suggesting that the mechanisms involved in neuromuscular junction maintenance might be disturbed during aging. In addition, there is now evidence that behavioral paradigms and signaling pathways that are involved in longevity also affect neuromuscular junction stability and sarcopenia.
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Affiliation(s)
- Lionel A. Tintignac
- Biozentrum, University of Basel, Basel, Switzerland; Department of Biomedicine, University of Basel, Basel, Switzerland; and INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Hans-Rudolf Brenner
- Biozentrum, University of Basel, Basel, Switzerland; Department of Biomedicine, University of Basel, Basel, Switzerland; and INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
| | - Markus A. Rüegg
- Biozentrum, University of Basel, Basel, Switzerland; Department of Biomedicine, University of Basel, Basel, Switzerland; and INRA, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France
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14
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Westermark P, Herzel H. Mechanism for 12 Hr Rhythm Generation by the Circadian Clock. Cell Rep 2013; 3:1228-38. [DOI: 10.1016/j.celrep.2013.03.013] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 01/25/2013] [Accepted: 03/12/2013] [Indexed: 11/30/2022] Open
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15
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Molecular mechanisms underlying maturation and maintenance of the vertebrate neuromuscular junction. Trends Neurosci 2012; 35:441-53. [PMID: 22633140 DOI: 10.1016/j.tins.2012.04.005] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 04/09/2012] [Accepted: 04/15/2012] [Indexed: 01/22/2023]
Abstract
The vertebrate neuromuscular junction (NMJ), a peripheral synapse formed between motoneuron and skeletal muscle, is characterized by a protracted postnatal period of maturation and life-long maintenance. In neuromuscular disorders such as congenital myasthenic syndromes (CMSs), disruptions of NMJ maturation and/or maintenance are frequently observed. In particular, defective neuromuscular transmission associated with structural and molecular abnormalities at the pre- and postsynaptic membranes, as well as at the synaptic cleft, has been reported in these patients. Here, we review recent advances in the understanding of molecular and cellular events that mediate NMJ maturation and maintenance. The underlying regulatory mechanisms, including key molecular regulators at the presynaptic nerve terminal, synaptic cleft, and postsynaptic muscle membrane, are discussed.
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16
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Molecular mechanisms for age-associated mitochondrial deficiency in skeletal muscle. J Aging Res 2012; 2012:768304. [PMID: 22548174 PMCID: PMC3324903 DOI: 10.1155/2012/768304] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 01/23/2012] [Indexed: 01/01/2023] Open
Abstract
The abundance, morphology, and functional properties of mitochondria decay in skeletal muscle during the process of ageing. Although the precise mechanisms remain to be elucidated, these mechanisms include decreased mitochondrial DNA (mtDNA) repair and mitochondrial biogenesis. Mitochondria possess their own protection system to repair mtDNA damage, which leads to defects of mtDNA-encoded gene expression and respiratory chain complex enzymes. However, mtDNA mutations have shown to be accumulated with age in skeletal muscle. When damaged mitochondria are eliminated by autophagy, mitochondrial biogenesis plays an important role in sustaining energy production and physiological homeostasis. The capacity for mitochondrial biogenesis has shown to decrease with age in skeletal muscle, contributing to progressive mitochondrial deficiency. Understanding how these endogenous systems adapt to altered physiological conditions during the process of ageing will provide a valuable insight into the underlying mechanisms that regulate cellular homeostasis. Here we will summarize the current knowledge about the molecular mechanisms responsible for age-associated mitochondrial deficiency in skeletal muscle. In particular, recent findings on the role of mtDNA repair and mitochondrial biogenesis in maintaining mitochondrial functionality in aged skeletal muscle will be highlighted.
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17
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Ngo ST, Cole RN, Sunn N, Phillips WD, Noakes PG. Neuregulin-1 potentiates agrin-induced acetylcholine receptor clustering through muscle-specific kinase phosphorylation. J Cell Sci 2012; 125:1531-43. [PMID: 22328506 DOI: 10.1242/jcs.095109] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
At neuromuscular synapses, neural agrin (n-agrin) stabilizes embryonic postsynaptic acetylcholine receptor (AChR) clusters by signalling through the muscle-specific kinase (MuSK) complex. Live imaging of cultured myotubes showed that the formation and disassembly of primitive AChR clusters is a dynamic and reversible process favoured by n-agrin, and possibly other synaptic signals. Neuregulin-1 is a growth factor that can act through muscle ErbB receptor kinases to enhance synaptic gene transcription. Recent studies suggest that neuregulin-1-ErbB signalling can modulate n-agrin-induced AChR clustering independently of its effects on transcription. Here we report that neuregulin-1 increased the size of developing AChR clusters when injected into muscles of embryonic mice. We investigated this phenomenon using cultured myotubes, and found that in the ongoing presence of n-agrin, neuregulin-1 potentiates AChR clustering by increasing the tyrosine phosphorylation of MuSK. This potentiation could be blocked by inhibiting Shp2, a postsynaptic tyrosine phosphatase known to modulate the activity of MuSK. Our results provide new evidence that neuregulin-1 modulates the signaling activity of MuSK and hence might function as a second-order regulator of postsynaptic AChR clustering at the neuromuscular synapse. Thus two classic synaptic signalling systems (neuregulin-1 and n-agrin) converge upon MuSK to regulate postsynaptic differentiation.
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Affiliation(s)
- Shyuan T Ngo
- School of Biomedical Sciences, University of Queensland, St. Lucia, 4072, Queensland, Australia
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18
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Meléndez LM, Colon K, Rivera L, Rodriguez-Franco E, Toro-Nieves D. Proteomic analysis of HIV-infected macrophages. J Neuroimmune Pharmacol 2011; 6:89-106. [PMID: 21153888 PMCID: PMC3028070 DOI: 10.1007/s11481-010-9253-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 11/23/2010] [Indexed: 12/21/2022]
Abstract
Mononuclear phagocytes (monocytes, macrophages, and microglia) play an important role in innate immunity against pathogens including HIV. These cells are also important viral reservoirs in the central nervous system and secrete inflammatory mediators and toxins that affect the tissue environment and function of surrounding cells. In the era of antiretroviral therapy, there are fewer of these inflammatory mediators. Proteomic approaches including surface enhancement laser desorption ionization, one- and two-dimensional difference in gel electrophoresis, and liquid chromatography tandem mass spectrometry have been used to uncover the proteins produced by in vitro HIV-infected monocytes, macrophages, and microglia. These approaches have advanced the understanding of novel mechanisms for HIV replication and neuronal damage. They have also been used in tissue macrophages that restrict HIV replication to understand the mechanisms of restriction for future therapies. In this review, we summarize the proteomic studies on HIV-infected mononuclear phagocytes and discuss other recent proteomic approaches that are starting to be applied to this field. As proteomic instruments and methods evolve to become more sensitive and quantitative, future studies are likely to identify more proteins that can be targeted for diagnosis or therapy and to uncover novel disease mechanisms.
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Affiliation(s)
- Loyda M Meléndez
- Department of Microbiology and Medical Zoology, School of Medicine, University of Puerto Rico, San Juan 00935, Puerto Rico.
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19
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Yu S, Cui K, Jothi R, Zhao DM, Jing X, Zhao K, Xue HH. GABP controls a critical transcription regulatory module that is essential for maintenance and differentiation of hematopoietic stem/progenitor cells. Blood 2011; 117:2166-78. [PMID: 21139080 PMCID: PMC3062326 DOI: 10.1182/blood-2010-09-306563] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Accepted: 11/30/2010] [Indexed: 12/15/2022] Open
Abstract
Maintaining a steady pool of self-renewing hematopoietic stem cells (HSCs) is critical for sustained production of multiple blood lineages. Many transcription factors and molecules involved in chromatin and epigenetic modifications have been found to be critical for HSC self-renewal and differentiation; however, their interplay is less understood. The transcription factor GA binding protein (GABP), consisting of DNA-binding subunit GABPα and transactivating subunit GABPβ, is essential for lymphopoiesis as shown in our previous studies. Here we demonstrate cell-intrinsic, absolute dependence on GABPα for maintenance and differentiation of hematopoietic stem/progenitor cells. Through genome-wide mapping of GABPα binding and transcriptomic analysis of GABPα-deficient HSCs, we identified Zfx and Etv6 transcription factors and prosurvival Bcl-2 family members including Bcl-2, Bcl-X(L), and Mcl-1 as direct GABP target genes, underlying its pivotal role in HSC survival. GABP also directly regulates Foxo3 and Pten and hence sustains HSC quiescence. Furthermore, GABP activates transcription of DNA methyltransferases and histone acetylases including p300, contributing to regulation of HSC self-renewal and differentiation. These systematic analyses revealed a GABP-controlled gene regulatory module that programs multiple aspects of HSC biology. Our studies thus constitute a critical first step in decoding how transcription factors are orchestrated to regulate maintenance and multipotency of HSCs.
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Affiliation(s)
- Shuyang Yu
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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20
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The neurogenic basic helix-loop-helix transcription factor NeuroD6 confers tolerance to oxidative stress by triggering an antioxidant response and sustaining the mitochondrial biomass. ASN Neuro 2010; 2:e00034. [PMID: 20517466 PMCID: PMC2874871 DOI: 10.1042/an20100005] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 04/09/2010] [Accepted: 04/21/2010] [Indexed: 12/21/2022] Open
Abstract
Preserving mitochondrial mass, bioenergetic functions and ROS (reactive oxygen species) homoeostasis is key to neuronal differentiation and survival, as mitochondria produce most of the energy in the form of ATP to execute and maintain these cellular processes. In view of our previous studies showing that NeuroD6 promotes neuronal differentiation and survival on trophic factor withdrawal, combined with its ability to stimulate the mitochondrial biomass and to trigger comprehensive antiapoptotic and molecular chaperone responses, we investigated whether NeuroD6 could concomitantly modulate the mitochondrial biomass and ROS homoeostasis on oxidative stress mediated by serum deprivation. In the present study, we report a novel role of NeuroD6 as a regulator of ROS homoeostasis, resulting in enhanced tolerance to oxidative stress. Using a combination of flow cytometry, confocal fluorescence microscopy and mitochondrial fractionation, we found that NeuroD6 sustains mitochondrial mass, intracellular ATP levels and expression of specific subunits of respiratory complexes upon oxidative stress triggered by withdrawal of trophic factors. NeuroD6 also maintains the expression of nuclear-encoded transcription factors, known to regulate mitochondrial biogenesis, such as PGC-1α (peroxisome-proliferator-activated receptor γ co-activator-1α), Tfam (transcription factor A, mitochondrial) and NRF-1 (nuclear respiratory factor-1). Finally, NeuroD6 triggers a comprehensive antioxidant response to endow PC12-ND6 cells with intracellular ROS scavenging capacity. The NeuroD6 effect is not limited to the classic induction of the ROS-scavenging enzymes, such as SOD2 (superoxide dismutase 2), GPx1 (glutathione peroxidase 1) and PRDX5 (peroxiredoxin 5), but also to the recently identified powerful ROS suppressors PGC-1α, PINK1 (phosphatase and tensin homologue-induced kinase 1) and SIRT1. Thus our collective results support the concept that the NeuroD6–PGC-1α–SIRT1 neuroprotective axis may be critical in co-ordinating the mitochondrial biomass with the antioxidant reserve to confer tolerance to oxidative stress.
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Key Words
- AD, Alzheimer’s disease
- AM, acetoxymethyl ester
- COX, cytochrome c oxidase
- DAPI, 4′,6-diamidino-2-phenylindole
- DIC, differential interference contrast
- Drp1, dynamin-related protein 1
- ETC, electron transfer chain
- GABP-α, GA-binding protein-α
- GAPDH, glyceraldehyde-3-phosphate dehydrogenase
- GFP, green fluorescent protein
- GPx1, glutathione peroxidase 1
- HSP, heat-shock protein
- MMP, mitochondrial membrane potential
- MTG, MitoTracker® Green
- MTR, MitoTracker® Red
- Mfn2, mitofusin 2
- Mg-Gr, Magnesium Green
- NRF, nuclear respiratory factor
- NT-PGC-1α, N-terminal-truncated PGC-1α
- NeuroD family
- OPA1, optic atrophy 1
- OXPHOS, oxidative phosphorylation
- PDL, poly-d-lysine
- PGC-1α, peroxisome-proliferator-activated receptor γ co-activator-1α
- PINK1, phosphatase and tensin homologue-induced kinase 1
- PRDX5, peroxiredoxin 5
- ROS, reactive oxygen species
- SIRT1
- SOD, superoxide dismutase
- Tfam, transcription factor A, mitochondrial
- WGA, wheatgerm agglutinin
- bHLH, basic helix–loop–helix
- mitochondria
- mtDNA, mitochondrial DNA
- neuronal survival
- reactive oxygen species (ROS)
- transcriptional co-regulator peroxisome-proliferator-activated receptor γ co-activator-1α (PGC-1α)
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Yu S, Zhao DM, Jothi R, Xue HH. Critical requirement of GABPalpha for normal T cell development. J Biol Chem 2010; 285:10179-88. [PMID: 20139079 DOI: 10.1074/jbc.m109.088740] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
GA binding protein (GABP) consists of GABPalpha and GABPbeta subunits. GABPalpha is a member of Ets family transcription factors and binds DNA via its conserved Ets domain, whereas GABPbeta does not bind DNA but possesses transactivation activity. In T cells, GABP has been demonstrated to regulate the gene expression of interleukin-7 receptor alpha chain (IL-7Ralpha) and postulated to be critical in T cell development. To directly investigate its function in early thymocyte development, we used GABPalpha conditional knock-out mice where the exons encoding the Ets DNA-binding domain are flanked with LoxP sites. Ablation of GABPalpha with the Lck-Cre transgene greatly diminished thymic cellularity, blocked thymocyte development at the double negative 3 (DN3) stage, and resulted in reduced expression of T cell receptor (TCR) beta chain in DN4 thymocytes. By chromatin immunoprecipitation, we demonstrated in DN thymocytes that GABPalpha is associated with transcription initiation sites of genes encoding key molecules in TCR rearrangements. Among these GABP-associated genes, knockdown of GABPalpha expression by RNA interference diminished expression of DNA ligase IV, Artemis, and Ku80 components in DNA-dependent protein kinase complex. Interestingly, forced expression of prearranged TCR but not IL-7Ralpha can alleviate the DN3 block in GABPalpha-targeted mice. Our observations collectively indicate that in addition to regulating IL-7Ralpha expression, GABP is critically required for TCR rearrangements and hence normal T cell development.
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Affiliation(s)
- Shuyang Yu
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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22
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Abstract
Mitochondria play central roles in energy homeostasis, metabolism, signaling, and apoptosis. Accordingly, the abundance, morphology, and functional properties of mitochondria are finely tuned to meet cell-specific energetic, metabolic, and signaling demands. This tuning is largely achieved at the level of transcriptional regulation. A highly interconnected network of transcription factors regulates a broad set of nuclear genes encoding mitochondrial proteins, including those that control replication and transcription of the mitochondrial genome. The same transcriptional network senses cues relaying cellular energy status, nutrient availability, and the physiological state of the organism and enables short- and long-term adaptive responses, resulting in adjustments to mitochondrial function and mitochondrial biogenesis. Mitochondrial dysfunction is associated with many human diseases. Characterization of the transcriptional mechanisms that regulate mitochondrial biogenesis and function can offer insights into possible therapeutic interventions aimed at modulating mitochondrial function.
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Affiliation(s)
- M Benjamin Hock
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037, USA
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23
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Targeting the GA binding protein beta1L isoform does not perturb lymphocyte development and function. Mol Cell Biol 2008; 28:4300-9. [PMID: 18426908 DOI: 10.1128/mcb.01855-07] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
GA binding protein (GABP) is a ubiquitously expressed Ets family transcription factor that consists of two subunits, GABPalpha and GABPbeta. GABPalpha binds to DNA, and GABPbeta heterodimerizes with GABPalpha and possesses the ability to transactivate target genes. Our previous studies using GABPalpha-deficient mice revealed that GABPalpha is required for the development of both T and B cells. Two splice variants of GABPbeta are generated from the Gabpb1 locus and differ in their carboxy-terminal lengths and sequences. The longer isoform (GABPbeta1L) can homodimerize and thus form alpha(2)beta(2) tetramers depending on the gene context, whereas the shorter isoform (GABPbeta1S) cannot. In this study, we generated mice that are deficient in GABPbeta1L but that retain the expression of GABPbeta1S. Surprisingly, GABPbeta1L-/- mice had normal T- and B-cell development, and mature T and B cells showed normal responses to various stimuli. In contrast, targeting both GABPbeta1L and GABPbeta1S resulted in early embryonic lethality. Because of its incapability of forming homodimers, GABPbeta1S has been suspected to have a dominant negative role in regulating GABP target genes. Our findings argue against such a possibility and rather suggest that GABPbeta1S has a critical role in maintaining the transcriptional activity of the GABPalpha/beta complex.
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24
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Herndon CA, Fromm L. Neuregulin-1 induces acetylcholine receptor transcription in the absence of GABPα phosphorylation. J Neurosci Res 2008; 86:982-91. [DOI: 10.1002/jnr.21563] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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25
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Hippenmeyer S, Huber RM, Ladle DR, Murphy K, Arber S. ETS Transcription Factor Erm Controls Subsynaptic Gene Expression in Skeletal Muscles. Neuron 2007; 55:726-40. [PMID: 17785180 DOI: 10.1016/j.neuron.2007.07.028] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Revised: 06/22/2007] [Accepted: 07/24/2007] [Indexed: 11/23/2022]
Abstract
Accumulation of specific proteins at synaptic structures is essential for synapse assembly and function, but mechanisms regulating local protein enrichment remain poorly understood. At the neuromuscular junction (NMJ), subsynaptic nuclei underlie motor axon terminals within extrafusal muscle fibers and are transcriptionally distinct from neighboring nuclei. In this study, we show that expression of the ETS transcription factor Erm is highly concentrated at subsynaptic nuclei, and its mutation in mice leads to severe downregulation of many genes with normally enriched subsynaptic expression. Erm mutant mice display an expansion of the muscle central domain in which acetylcholine receptor (AChR) clusters accumulate, show gradual fragmentation of AChR clusters, and exhibit symptoms of muscle weakness mimicking congenital myasthenic syndrome (CMS). Together, our findings define Erm as an upstream regulator of a transcriptional program selective to subsynaptic nuclei at the NMJ and underscore the importance of transcriptional control of local synaptic protein accumulation.
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Affiliation(s)
- Simon Hippenmeyer
- Biozentrum, Department of Cell Biology, University of Basel, Klingelbergstrasse 70, 4056 Basel, Switzerland
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