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Cholinergic systems mediate action from movement to higher consciousness. Behav Brain Res 2011; 221:488-98. [DOI: 10.1016/j.bbr.2009.12.046] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 12/26/2009] [Indexed: 02/06/2023]
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Irrcher I, Hood DA. Regulation of Egr-1, SRF, and Sp1 mRNA expression in contracting skeletal muscle cells. J Appl Physiol (1985) 2004; 97:2207-13. [PMID: 15310743 DOI: 10.1152/japplphysiol.00388.2004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The early cellular signals associated with contractile activity initiate the activation and induction of transcription factors that regulate changes in skeletal muscle phenotype. The transcription factors Egr-1, Sp1, and serum response factor (SRF) are potentially important mediators of mitochondrial biogenesis based on the prevalence of binding sites for them in the promoter regions of genes encoding mitochondrial proteins, including PGC-1α, the important regulator of mitochondrial biogenesis. Thus, to further define a role for transcription factors at the onset of contractile activity, we examined the time-dependent alterations in Egr-1, Sp1, and SRF mRNA and the levels in electrically stimulated mouse C2C12skeletal muscle cells. Early transient increases in Egr-1 mRNA levels within 30 min ( P < 0.05) of contractile activity led to threefold increases ( P < 0.05) in Egr-1 protein by 60 min. The increase in Egr-1 mRNA was not because of increased stability, as Egr-1 mRNA half-life after 30 min of stimulation showed only a 58% decline. Stimulation of muscle cells had no effect on Sp1 mRNA but led to progressive increases ( P < 0.05) in SRF mRNA by 30 and 60 min. This was not matched by increases in SRF protein but occurred coincident with increases ( P < 0.05) in SRF-serum response element DNA binding at 30 and 60 min as a result of SRF phosphorylation on serine-103. To assess the importance of the recovery period, 12 h of continuous contractile activity was compared with four successive 3-h bouts, with an intervening 21-h recovery period after each bout. Continuous contractile activity led to a twofold increase ( P < 0.05) in Egr-1 mRNA, no change in SRF mRNA, and a 43% decrease in Sp1 mRNA expression. The recovery period prevented the decline in Sp1 mRNA, produced a decrease in Egr-1 mRNA, and had no effect on SRF mRNA. Thus continuous and intermittent contractile activity evoked different specific transcription factor expression patterns, which may ultimately contribute to divergent qualitative, or temporal patterns of, phenotypic adaptation in muscle.
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Affiliation(s)
- Isabella Irrcher
- Dept. of Kinesiology and Health Science, York University, Toronto, Ontario, Canada M3J 1P3
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Freyssenet D, Irrcher I, Connor MK, Di Carlo M, Hood DA. Calcium-regulated changes in mitochondrial phenotype in skeletal muscle cells. Am J Physiol Cell Physiol 2004; 286:C1053-61. [PMID: 15075204 DOI: 10.1152/ajpcell.00418.2003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cytochrome c expression and mitochondrial biogenesis can be invoked by elevated intracellular Ca2+in muscle cells. To characterize the potential role of Ca2+as a messenger involved in mitochondrial biogenesis in muscle, we determined the effects of the Ca2+ionophore A-23187 on the expression of nuclear- and mitochondrially encoded genes. Treatment of myotubes with 1 μM A-23187 for 48–96 h increased nuclear-encoded β-subunit F1ATPase and malate dehydrogenase (MDH) mRNA levels by 50–100% ( P < 0.05) but decreased mRNA levels of glutamate dehydrogenase (GDH) by 19% ( P < 0.05). mRNA levels of the cytochrome c oxidase (COX) nuclear-encoded subunits IV, Vb, and VIc were unchanged, whereas the mitochondrially encoded subunits COX II and COX III were decreased by 30 and 70%, respectively ( P < 0.05). This was paralleled by a 20% decrease ( P < 0.05) in COX activity. These data suggest that cytoplasmic Ca2+differentially regulates the mRNA level of nuclear and mitochondrial genes. The decline in COX II and III mRNA may be mediated by Tfam, because A-23187 modestly reduced Tfam levels by 48 h. A-23187 induced time-dependent increases in Egr-1 mRNA, along with the activation of ERK1/2 and AMP-activated protein kinase. MEK inhibition with PD-98059 attenuated the increase in Egr-1 mRNA. A-23187 also increased Egr-1, serum response factor, and Sp1 protein expression, transcription factors implicated in mitochondrial biogenesis. Egr-1 overexpression increased nuclear-encoded cytochrome c transcriptional activation by 1.5-fold ( P < 0.05) and reduced GDH mRNA by 37% ( P < 0.05) but had no effect on MDH or β-subunit F1ATPase mRNA. These results indicate that changes in intracellular Ca2+can modify mitochondrial phenotype, in part via the involvement of Egr-1.
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Carrasco MA, Riveros N, Ríos J, Müller M, Torres F, Pineda J, Lantadilla S, Jaimovich E. Depolarization-induced slow calcium transients activate early genes in skeletal muscle cells. Am J Physiol Cell Physiol 2003; 284:C1438-47. [PMID: 12529240 DOI: 10.1152/ajpcell.00117.2002] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The signaling mechanisms by which skeletal muscle electrical activity leads to changes in gene expression remain largely undefined. We have reported that myotube depolarization induces calcium signals in the cytosol and nucleus via inositol 1,4,5-trisphosphate (IP(3)) and phosphorylation of both ERK1/2 and cAMP-response element-binding protein (CREB). We now describe the calcium dependence of P-CREB and P-ERK induction and of the increases in mRNA of the early genes c-fos, c-jun, and egr-1. Increased phosphorylation and early gene activation were maintained in the absence of extracellular calcium, while the increase in intracellular calcium induced by caffeine could mimic the depolarization stimulus. Depolarization performed either in the presence of the IP(3) inhibitors 2-aminoethoxydiphenyl borate or xestospongin C or on cells loaded with BAPTA-AM, in which slow calcium signals were abolished, resulted in decreased activation of the early genes examined. Both early gene activation and CREB phosphorylation were inhibited by ERK phosphorylation blockade. These data suggest a role for calcium in the transcription-related events that follow membrane depolarization in muscle cells.
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MESH Headings
- Animals
- Caffeine/metabolism
- Calcium/metabolism
- Cells, Cultured
- Cyclic AMP Response Element-Binding Protein/genetics
- Cyclic AMP Response Element-Binding Protein/metabolism
- DNA-Binding Proteins
- Early Growth Response Protein 1
- Enzyme Inhibitors/metabolism
- Gene Expression Regulation, Developmental
- Genes, Immediate-Early
- Genes, fos
- Genes, jun
- Immediate-Early Proteins
- Membrane Potentials/physiology
- Mitogen-Activated Protein Kinases/genetics
- Mitogen-Activated Protein Kinases/metabolism
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/cytology
- Muscle, Skeletal/physiology
- Phosphorylation
- Potassium/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Signal Transduction/physiology
- Transcription Factors
- Transcriptional Activation
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Affiliation(s)
- Maria Angélica Carrasco
- Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 6530499, Chile.
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Connor MK, Irrcher I, Hood DA. Contractile activity-induced transcriptional activation of cytochrome C involves Sp1 and is proportional to mitochondrial ATP synthesis in C2C12 muscle cells. J Biol Chem 2001; 276:15898-904. [PMID: 11279044 DOI: 10.1074/jbc.m100272200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Contractile activity induces adaptations in the expression of genes encoding skeletal muscle mitochondrial proteins; however, the putative signals responsible for these adaptations remain unknown. We used electrical stimulation (5 Hz, 65 V) of C2C12 muscle cells in culture to define some of the mechanisms involved in contractile activity-induced changes in cytochrome c gene expression. Chronic contractile activity (4 days, 3 h/day) augmented cytochrome c mRNA by 1.6-fold above control cells. This was likely mediated by increases in transcriptional activation, because cells transfected with full-length (-726 base pairs) or minimal (-66 base pairs) cytochrome c promoter/chloramphenicol acetyltransferase reporter constructs demonstrated contractile activity-induced 1.5-1.7-fold increases in the absence of contractile activity-induced increases in mRNA stability. Transcriptional activation of the -726 promoter was abolished when muscle contraction was inhibited at various subcellular locations by pretreatment with either the Na(+) channel blocker tetrodotoxin, the intracellular Ca(2+) chelator 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl) ester, or the myosin ATPase inhibitor 2,3-butanedione monoxime. It was further reduced in unstimulated cells when mitochondrial ATP synthesis was impaired using the uncoupler 2,4-dinitrophenol. Because the contractile activity-induced response was evident within the minimal promoter, electromobility shift assays performed within the first intron (+75 to +104 base pairs) containing Sp1 sites revealed an elevated DNA binding in response to contractile activity. This was paralleled by increases in Sp1 protein levels. Sp1 overexpression studies also led to increases in cytochrome c transactivation and mRNA levels. These data suggest that variations in the rate of mitochondrial ATP synthesis are important in determining cytochrome c gene expression in muscle cells and that this is mediated, in part, by Sp1-induced increases in cytochrome c transcription.
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Affiliation(s)
- M K Connor
- Departments of Biology and Kinesiology and Health Science, York University, Toronto, Ontario M3J 1P3, Canada
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Oudit GY, Kassiri Z, Sah R, Ramirez RJ, Zobel C, Backx PH. The molecular physiology of the cardiac transient outward potassium current (I(to)) in normal and diseased myocardium. J Mol Cell Cardiol 2001; 33:851-72. [PMID: 11343410 DOI: 10.1006/jmcc.2001.1376] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
G. Y. Oudit, Z. Kassiri, R. Sah, R. J. Ramirez, C. Zobel and P. H. Backx. The Molecular Physiology of the Cardiac Transient Outward Potassium Current (I(to)) in Normal and Diseased Myocardium. Journal of Molecular and Cellular Cardiology (2001) 33, 851-872. The Ca(2+)-independent transient outward potassium current (I(to)) plays an important role in early repolarization of the cardiac action potential. I(to)has been clearly demonstrated in myocytes from different cardiac regions and species. Two kinetic variants of cardiac I(to)have been identified: fast I(to), called I(to,f), and slow I(to), called I(to,s). Recent findings suggest that I(to,f)is formed by assembly of K(v4.2)and/or K(v4.3)alpha pore-forming voltage-gated subunits while I(to,s)is comprised of K(v1.4)and possibly K(v1.7)subunits. In addition, several regulatory subunits and pathways modulating the level and biophysical properties of cardiac I(to)have been identified. Experimental findings and data from computer modeling of cardiac action potentials have conclusively established an important physiological role of I(to)in rodents, with its role in large mammals being less well defined due to complex interplay between a multitude of cardiac ionic currents. A central and consistent electrophysiological change in cardiac disease is the reduction in I(to)density with a loss of heterogeneity of I(to)expression and associated action potential prolongation. Alterations of I(to)in rodent cardiac disease have been linked to repolarization abnormalities and alterations in intracellular Ca(2+)homeostasis, while in larger mammals the link with functional changes is far less certain. We review the current literature on the molecular basis for cardiac I(to)and the functional consequences of changes in I(to)that occur in cardiovascular disease.
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Affiliation(s)
- G Y Oudit
- Department of Medicine and Physiology, Toronto General Hospital, 101 College Street, Toronto, M5G 2C4, Canada
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Studzinski DM, Callahan RE, Benjamins JA. Increased intracellular calcium alters myelin gene expression in the N20.1 oligodendroglial cell line. J Neurosci Res 1999. [DOI: 10.1002/(sici)1097-4547(19990901)57:5<633::aid-jnr5>3.0.co;2-i] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wang X, Marton LS, Weir BK, Macdonald RL. Immediate early gene expression in vascular smooth-muscle cells synergistically induced by hemolysate components. J Neurosurg 1999; 90:1083-90. [PMID: 10350256 DOI: 10.3171/jns.1999.90.6.1083] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Vasospasm after subarachnoid hemorrhage is associated with changes in modulators of vascular tone in the arterial wall and is related to the presence of erythrocyte hemolysate in the subarachnoid space. The purpose of this study was to determine the compounds in erythrocyte hemolysate that are responsible for changing smooth-muscle cell gene expression. METHODS Rat aorta smooth-muscle cells were exposed to erythrocyte hemolysate in vitro and the effects on immediate early gene messenger (m)RNA levels were determined by competitive reverse transcriptase-polymerase chain reaction. Message levels for c-fos, jun B, and c-jun were increased in the presence of hemolysate, reaching maximum expression between 30 and 60 minutes, whereas the level of jun D mRNA was unaffected. Increasing doses of hemolysate caused greater expression of c-fos and jun B, but not c-jun. Adenosine triphosphate and hemoglobin, possible spasmogens present in hemolysate, caused much smaller and more rapid increases in c-fos expression than whole hemolysate. Size fractionation showed that all of the c-fos mRNA-inducing activity of hemolysate was recovered with molecules greater than 6 kD. Following separation of hemolysate proteins by hydrophobic interaction chromatography, only one of the three fractions had partial activity. Recombining the three fractions, however, yielded greater c-fos activation than any combination of two. CONCLUSIONS Multiple high-molecular-weight components present in erythrocytes have synergistic effects on gene expression in smooth-muscle cells. The differences in patterns of gene induction suggest that multiple signaling pathways are activated.
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Affiliation(s)
- X Wang
- Department of Surgery, Pritzker School of Medicine, University of Chicago, Illinois 60637, USA
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von der Kammer H, Mayhaus M, Albrecht C, Enderich J, Wegner M, Nitsch RM. Muscarinic acetylcholine receptors activate expression of the EGR gene family of transcription factors. J Biol Chem 1998; 273:14538-44. [PMID: 9603968 DOI: 10.1074/jbc.273.23.14538] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In order to search for genes that are activated by muscarinic acetylcholine receptors (mAChRs), we used an mRNA differential display approach in HEK293 cells expressing m1AChR. The zinc-finger transcription factor genes Egr-1, Egr-2, and Egr-3 were identified. Northern blot analyses confirmed that mRNA levels of Egr-1, Egr-2, and Egr-3 increased readily after m1AChR stimulation and that a maximum was attained within 50 min. At that time, Egr-4 mRNA was also detectable. Western blots and electromobility shift assays demonstrated synthesis of EGR-1 and EGR-3, as well as binding to DNA recognition sites in response to m1AChR activation. Activation of m1AChR increased transcription from EGR-dependent promoters, including the acetylcholinesterase gene promoter. Activity-dependent regulation of Egr-1 mRNA expression and EGR-1 protein synthesis was also observed in cells expressing m2, m3, or m4AChR subtypes. Increased EGR-1 synthesis was mimicked by phorbol myristate acetate, but not by forskolin, and receptor-stimulated EGR-1 synthesis was partially inhibited by phorbol myristate acetate down-regulation. Together, our results demonstrate that muscarinic receptor signaling activates the EGR transcription factor family and that PKC may be involved in intracellular signaling. The data suggest that transcription of EGR-dependent target genes, including the AChE gene, can be under the control of extracellular and intracellular signals coupled to muscarinic receptors.
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Affiliation(s)
- H von der Kammer
- Center for Molecular Neurobiology and Alzheimer's Disease Research Group, University of Hamburg, Martinistrasse 52, D-20246 Hamburg, Germany
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Abu-Shakra S, Alhalabi M, Nachtman F, Schemidt R, Brusilow W. Anabolic steroids induce injury and apoptosis of differentiated skeletal muscle. J Neurosci Res 1997. [DOI: 10.1002/(sici)1097-4547(19970115)47:2<186::aid-jnr7>3.0.co;2-b] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abu-Shakra SR, Nachtman FC. Anabolic steroids induce skeletal muscle injury and immediate early gene expression through a receptor-independent mechanism. Ann N Y Acad Sci 1995; 761:395-9. [PMID: 7625745 DOI: 10.1111/j.1749-6632.1995.tb31401.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- S R Abu-Shakra
- Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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