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Ahmad N, de la Serna IL, Marathe HG, Fan X, Dube P, Zhang S, Haller ST, Kennedy DJ, Pestov NB, Modyanov NN. Eutherian-Specific Functions of BetaM Acquired through Atp1b4 Gene Co-Option in the Regulation of MyoD Expression. Life (Basel) 2023; 13:414. [PMID: 36836771 PMCID: PMC9962273 DOI: 10.3390/life13020414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/20/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023] Open
Abstract
Vertebrate ATP1B4 genes represent a rare instance of orthologous gene co-option, resulting in radically different functions of the encoded BetaM proteins. In lower vertebrates, BetaM is a Na, K-ATPase β-subunit that is a component of ion pumps in the plasma membrane. In placental mammals, BetaM lost its ancestral role and, through structural alterations of the N-terminal domain, became a skeletal and cardiac muscle-specific protein of the inner nuclear membrane, highly expressed during late fetal and early postnatal development. We previously determined that BetaM directly interacts with the transcriptional co-regulator SKI-interacting protein (SKIP) and is implicated in the regulation of gene expression. This prompted us to investigate a potential role for BetaM in the regulation of muscle-specific gene expression in neonatal skeletal muscle and cultured C2C12 myoblasts. We found that BetaM can stimulate expression of the muscle regulatory factor (MRF), MyoD, independently of SKIP. BetaM binds to the distal regulatory region (DRR) of MyoD, promotes epigenetic changes associated with activation of transcription, and recruits the SWI/SNF chromatin remodeling subunit, BRG1. These results indicate that eutherian BetaM regulates muscle gene expression by promoting changes in chromatin structure. These evolutionarily acquired new functions of BetaM might be very essential and provide evolutionary advantages to placental mammals.
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Affiliation(s)
- Nisar Ahmad
- Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Ivana L. de la Serna
- Department of Cell and Cancer Biology, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Himangi G. Marathe
- Department of Cell and Cancer Biology, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Xiaoming Fan
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Prabhatchandra Dube
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Shungang Zhang
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Steven T. Haller
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - David J. Kennedy
- Department of Medicine, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Nikolay B. Pestov
- Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
| | - Nikolai N. Modyanov
- Department of Physiology and Pharmacology, Center for Diabetes and Endocrine Research, College of Medicine and Life Sciences, The University of Toledo, Toledo, OH 43614, USA
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2
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Silva NC, Alvarez AM, DeOcesano-Pereira C, Fortes-Dias CL, Moreira V. Catalytically active phospholipase A 2 myotoxin from Crotalus durissus terrificus induces proliferation and differentiation of myoblasts dependent on prostaglandins produced by both COX-1 and COX-2 pathways. Int J Biol Macromol 2021; 187:603-613. [PMID: 34314795 DOI: 10.1016/j.ijbiomac.2021.07.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/18/2021] [Accepted: 07/19/2021] [Indexed: 01/18/2023]
Abstract
Although crotoxin B (CB) is a well-established catalytically active secretory phospholipase A2 group IIA (sPLA2-IIA) myotoxin, we investigated its potential stimulatory effect on myogenesis with the involvement of prostaglandins (PGs) produced by cyclooxygenase (COX)-1 and -2 pathways. Myoblast C2C12 were cultured in proliferation or commitment protocols and incubated with CB followed by lumiracoxib (selective COX-2 inhibitor) or valeryl salicylate (selective COX-1 inhibitor) and subjected to analysis of PG release, cell proliferation and activation of myogenic regulatory factors (MRFs). Our data showed that CB in non-cytotoxic concentrations induces an increase of COX-2 protein expression and stimulates the activity of both COX isoforms to produce PGE2, PGD2 and 15d-PGJ2. CB induced an increase in the proliferation of C2C12 myoblast cells dependent on PGs from both COX-1 and COX-2 pathways. In addition, CB stimulated the activity of Pax7, MyoD, Myf5 and myogenin in proliferated cells. Otherwise, CB increased myogenin activity but not MyoD in committed cells. Our findings evidence the role of COX-1- and COX-2-derived PGs in modulating CB-induced activation of MRFs. This study contributes to the knowledge that CB promote early myogenic events via regulatory mechanisms on PG-dependent COX pathways, showing new concepts about the effect of sPLA2-IIA in skeletal muscle repair.
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Affiliation(s)
- Nadine C Silva
- Pharmacology Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP 04044-020, Brazil
| | - Angela M Alvarez
- Pharmacology Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP 04044-020, Brazil; Centre of Excellence in New Target Discovery (CENTD), Butantan Institute, São Paulo, SP 05503-900, Brazil.
| | - Carlos DeOcesano-Pereira
- Centre of Excellence in New Target Discovery (CENTD), Butantan Institute, São Paulo, SP 05503-900, Brazil.
| | | | - Vanessa Moreira
- Pharmacology Department, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP 04044-020, Brazil.
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3
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The skeletal muscle arachidonic acid cascade in health and inflammatory disease. Nat Rev Rheumatol 2014; 10:295-303. [PMID: 24468934 DOI: 10.1038/nrrheum.2014.2] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Muscle atrophy and weakness are often observed in patients with chronic inflammatory diseases, and are the major clinical features of the autoimmune myopathies, polymyositis and dermatomyositis. A general understanding of the pathogenesis of muscle atrophy and the impaired muscle function associated with chronic inflammatory diseases has not been clarified. In this context, arachidonic acid metabolites, such as the prostaglandin and leukotriene subfamilies, are of interest because they contribute to immune and nonimmune processes. Accumulating evidence suggests that prostaglandins and leukotrienes are involved in causing muscular pain and inflammation, and also in myogenesis and the repair of muscles. In this Review, we summarize novel findings that implicate prostaglandins and leukotrienes in the muscle atrophy and weakness that occur in inflammatory diseases of the muscles, with a focus on inflammatory myopathies. We discuss the role of the arachidonic acid cascade in skeletal muscle growth and function, and individual metabolites as potential therapeutic targets for the treatment of inflammatory muscle diseases.
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4
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ZEB1 imposes a temporary stage-dependent inhibition of muscle gene expression and differentiation via CtBP-mediated transcriptional repression. Mol Cell Biol 2013; 33:1368-82. [PMID: 23339872 DOI: 10.1128/mcb.01259-12] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Skeletal muscle development is orchestrated by the myogenic regulatory factor MyoD, whose activity is blocked in myoblasts by proteins preventing its nuclear translocation and/or binding to G/C-centered E-boxes in target genes. Recent evidence indicates that muscle gene expression is also regulated at the cis level by differential affinity for DNA between MyoD and other E-box binding proteins during myogenesis. MyoD binds to G/C-centered E-boxes, enriched in muscle differentiation genes, in myotubes but not in myoblasts. Here, we used cell-based and in vivo Drosophila, Xenopus laevis, and mouse models to show that ZEB1, a G/C-centered E-box binding transcriptional repressor, imposes a temporary stage-dependent inhibition of muscle gene expression and differentiation via CtBP-mediated transcriptional repression. We found that, contrary to MyoD, ZEB1 binds to G/C-centered E-boxes in muscle differentiation genes at the myoblast stage but not in myotubes. Its knockdown results in precocious expression of muscle differentiation genes and acceleration of myotube formation. Inhibition of muscle genes by ZEB1 occurs via transcriptional repression and involves recruitment of the CtBP corepressor. Lastly, we show that the pattern of gene expression associated with muscle differentiation is accelerated in ZEB1(-/-) mouse embryos. These results set ZEB1 as an important regulator of the temporal pattern of gene expression controlling muscle differentiation.
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5
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Redshaw Z, Loughna PT. Oxygen concentration modulates the differentiation of muscle stem cells toward myogenic and adipogenic fates. Differentiation 2012; 84:193-202. [PMID: 22790207 DOI: 10.1016/j.diff.2012.06.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 03/23/2012] [Accepted: 06/05/2012] [Indexed: 01/08/2023]
Abstract
The physiological oxygen concentration of many tissues is far lower than that in which cells are typically cultured in vitro and this may inadvertently influence the proliferation and differentiation potential of many cell types. Muscle derived stem cells, known as satellite cells are responsible for the maintenance and repair of muscle tissue post-natally and in vivo would be exposed to oxygen concentrations of ∼2-5%. Relatively few studies describe the function of these cells in large animal models and here we investigate the influence oxygen concentration has on modulating porcine muscle derived stem cell fate. We compared cells derived from two metabolically distinct muscles, the diaphragm and the hind limb semi-membranosus (SM) muscle. The two sub-populations responded differently to culture at atmospheric (∼20%) and physiological (∼5%) oxygen concentration. While myogenesis was enhanced in both populations at low oxygen, noticeably diaphragm derived cells exhibited greater myotube formation, than those from SM. The trans-differentiation of cells derived from these two sources was similarly affected, with considerable differences seen in adipogenic and neuronal tendencies. In addition to the effect of oxygen on cell phenotype, the expression of key signalling proteins varied between the two sub-populations during early time-points of induced differentiation, suggesting altered regulation of muscle specific stem cells under these conditions. While differences in muscle stem cell potential requires further investigation, the culture of cells in physiological oxygen concentration appears as fundamental to recreating the micro-environmental niche as routinely used factors such as cytokines, substrata and matrices.
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Affiliation(s)
- Zoe Redshaw
- The University of Nottingham, School of Veterinary Medicine and Science, Sutton Bonington Campus, Sutton Bonington, Leics LE12 5RD, United Kingdom.
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6
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Very low density lipoprotein receptor promotes adipocyte differentiation and mediates the proadipogenic effect of peroxisome proliferator-activated receptor gamma agonists. Biochem Pharmacol 2011; 82:1950-62. [DOI: 10.1016/j.bcp.2011.09.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Revised: 08/30/2011] [Accepted: 09/02/2011] [Indexed: 11/24/2022]
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7
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Changes of peroxisome proliferator-activated receptor-γ on crushed rat sciatic nerves and differentiated primary Schwann cells. J Mol Neurosci 2011; 47:380-8. [PMID: 22094441 DOI: 10.1007/s12031-011-9662-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 09/30/2011] [Indexed: 12/14/2022]
Abstract
Peroxisome proliferator-activated receptor-γ (PPAR-γ) has been found to play an essential role in cell proliferation, but whether it was involved in Schwann cells differentiation has never been studied. We have found in sciatic nerve injury that expression of PPAR-γ decreases mainly in Schwann cells, and it was also increased in differentiated Schwann cells. Further, activated PPAR-γ by the endogenous ligand 15 d-PGJ(2) increased expressions of PPAR-γ level and Schwann cell differentiation, and this effect may be protected by its antagonist GDW9662. These results indicate that PPAR-γ could promote Schwann cell differentiation, which plays an important role in peripheral nerve injury and regeneration.
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8
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Pereira Lopes JEF, Barbosa MR, Stella CN, Santos WA, Pereira EM, Nogueira-Neto J, Augusto EM, Silva LV, Smaili SS, Gomes LF. In vivo anti-angiogenic effects further support the promise of the antineoplasic activity of methyl jasmonate. BRAZ J BIOL 2010; 70:443-9. [PMID: 20549071 DOI: 10.1590/s1519-69842010000200029] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Accepted: 04/03/2009] [Indexed: 11/22/2022] Open
Abstract
Molecular plant components have long been aimed at the angiogenesis and anti-angiogenesis pathways, and have been tested as sources for antineoplasic drugs with promising success. The present work deals with the anti-angiogenic effects of Methyl Jasmonate. Jasmonate derivatives were demonstrated to selectively damage the mitochondria of cancer cells. In vitro, 1-10 mM Methyl Jasmonate induced the cell death of the human umbilical vein endothelial cells (HUVEC) and the Murine melanoma cells (B16F10), while micromolar concentrations were ineffective. In vivo, comparable concentrations were toxic and reduced the vessel density of the Chorioallantoic Membrane of the Chicken Embryo (CAM). However, 1-10 microM concentrations produced a complex effect. There was increased capillary budding, but the new vessels were leakier and less organised than corresponding controls. It is suggested that not only direct toxicity, but also the drug effects upon angiogenesis are relevant to the antineoplasic effects of Methyl Jasmonate.
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Affiliation(s)
- J E F Pereira Lopes
- Departamento de Análises Clínicas e Toxicológicas, Universidade de São Paulo, SP, Brazil
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9
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Yoda E, Hachisu K, Taketomi Y, Yoshida K, Nakamura M, Ikeda K, Taguchi R, Nakatani Y, Kuwata H, Murakami M, Kudo I, Hara S. Mitochondrial dysfunction and reduced prostaglandin synthesis in skeletal muscle of Group VIB Ca2+-independent phospholipase A2gamma-deficient mice. J Lipid Res 2010; 51:3003-15. [PMID: 20625036 DOI: 10.1194/jlr.m008060] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Group VIB Ca(2+)-independent phospholipase A(2)γ (iPLA(2)γ) is a membrane-bound iPLA(2) enzyme with unique features, such as the utilization of distinct translation initiation sites and the presence of mitochondrial and peroxisomal localization signals. Here we investigated the physiological functions of iPLA(2)γ by disrupting its gene in mice. iPLA(2)γ-knockout (KO) mice were born with an expected Mendelian ratio and appeared normal and healthy at the age of one month but began to show growth retardation from the age of two months as well as kyphosis and significant muscle weakness at the age of four months. Electron microscopy revealed swelling and reduced numbers of mitochondria and atrophy of myofilaments in iPLA(2)γ-KO skeletal muscles. Increased lipid peroxidation and the induction of several oxidative stress-related genes were also found in the iPLA(2)γ-KO muscles. These results provide evidence that impairment of iPLA(2)γ causes mitochondrial dysfunction and increased oxidative stress, leading to the loss of skeletal muscle structure and function. We further found that the compositions of cardiolipin and other phospholipid subclasses were altered and that the levels of myoprotective prostanoids were reduced in iPLA(2)γ-KO skeletal muscle. Thus, in addition to maintenance of homeostasis of the mitochondrial membrane, iPLA(2)γ may contribute to modulation of lipid mediator production in vivo.
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Affiliation(s)
- Emiko Yoda
- Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan
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10
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Veliça P, Bunce CM. Prostaglandins in muscle regeneration. J Muscle Res Cell Motil 2008; 29:163-7. [DOI: 10.1007/s10974-008-9154-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 11/14/2008] [Indexed: 10/21/2022]
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11
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Durieux AC, Amirouche A, Banzet S, Koulmann N, Bonnefoy R, Pasdeloup M, Mouret C, Bigard X, Peinnequin A, Freyssenet D. Ectopic expression of myostatin induces atrophy of adult skeletal muscle by decreasing muscle gene expression. Endocrinology 2007; 148:3140-7. [PMID: 17395701 DOI: 10.1210/en.2006-1500] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Myostatin is a master regulator of myogenesis and early postnatal skeletal muscle growth. However, myostatin has been also involved in several forms of muscle wasting in adulthood, suggesting a functional role for myostatin in the regulation of skeletal muscle mass in adult. In the present study, localized ectopic expression of myostatin was achieved by gene electrotransfer of a myostatin expression vector into the tibialis anterior muscle of adult Sprague Dawley male rats. The corresponding empty vector was electrotransfected in contralateral muscle. Ectopic myostatin mRNA was abundantly present in muscles electrotransfected with myostatin expression vector, whereas it was undetectable in contralateral muscles. Overexpression of myostatin elicited a significant decrease in muscle mass (10 and 20% reduction 7 and 14 d after gene electrotransfer, respectively), muscle fiber cross-sectional area (15 and 30% reduction 7 and 14 d after gene electrotransfer, respectively), and muscle protein content (20% reduction). No decrease in fiber number was observed. Overexpression of myostatin markedly decreased the expression of muscle structural genes (myosin heavy chain IIb, troponin I, and desmin) and the expression of myogenic transcription factors (MyoD and myogenin). Incidentally, mRNA level of caveolin-3 and peroxisome proliferator activated receptor gamma coactivator-1alpha was also significantly decreased 14 d after myostatin gene electrotransfer. To conclude, our study demonstrates that myostatin-induced muscle atrophy elicits the down-regulation of muscle-specific gene expression. Our observations support an important role for myostatin in muscle atrophy in physiological and physiopathological situations where myostatin expression is induced.
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Affiliation(s)
- Anne-Cécile Durieux
- Unité Physiologie et Physiopathologie de l'Exercice et Handicap, Université Jean Monnet, 42023 Saint-Etienne cedex 2, France
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12
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Guerfali I, Manissolle C, Durieux AC, Bonnefoy R, Bartegi A, Freyssenet D. Calcineurin A and CaMKIV transactivate PGC-1α promoter, but differentially regulate cytochrome c promoter in rat skeletal muscle. Pflugers Arch 2007; 454:297-305. [PMID: 17273866 DOI: 10.1007/s00424-007-0206-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2006] [Revised: 12/21/2006] [Accepted: 01/04/2007] [Indexed: 10/23/2022]
Abstract
In skeletal muscle, slow-twitch fibers are highly dependent on mitochondrial oxidative metabolism suggesting the existence of common regulatory pathways in the control of slow muscle-specific protein expression and mitochondrial biogenesis. In this study, we determined whether peroxisome proliferator-activated receptor gamma co-activator-1alpha (PGC-1alpha) could transactivate promoters of nuclear-encoded mitochondrial protein (cytochrome c) and muscle-specific proteins (fast troponin I, MyoD). We also investigated if calcineurin A (CnA) and calcium/calmodulin kinase IV (CaMKIV) were involved in the regulation of PGC-1alpha and cytochrome c promoter. For this purpose, we took advantage of the gene electrotransfer technique, which allows acute expression of a gene of interest. Electrotransfer of a PGC-1alpha expression vector into rat Tibialis anterior muscle induced a strong transactivation of cytochrome c promoter (P < 0.001) independent of nuclear respiratory factor 1. PGC-1alpha gene electrotransfer did not transactivate fast troponin I promoter, whereas it did transactivate MyoD promoter (P < 0.05). Finally, whereas electrotransfers of CnA or CaMKIV expression vectors transactivated PGC-1alpha promoter (P < 0.001), gene electrotransfer of CaMKIV was only able to transactivate cytochrome c promoter. Taken together, these data suggest that CnA triggers PGC-1alpha promoter transactivation to drive the expression of non-mitochondrial proteins.
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Affiliation(s)
- Ibtissem Guerfali
- Unité Physiologie et Physiopathologie de l'Exercice et Handicap EA 3062, Faculté de Médecine, Université Jean Monnet, 15 rue Ambroise Paré, 42023 Saint-Etienne Cedex 2, France
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13
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Abstract
Cultivation of stem cells, like all cells in culture, is performed under conditions that cannot and do not replicate normal physiologic conditions. For example, direct exposure of cultured monolayer cells to serum contents is normally prevented in vivo by the vasculature. The heterogeneity of cells and signals between different cell types in an organ is certainly not captured when a single cell type is grown and studied in vitro. Gases, in particular, are not accounted for in routine tissue culture. Oxygen is fundamental for life and its concentration is an important signal for virtually all cellular processes. Nonetheless, oxygen is rarely taken into account in culturing stem and other cells. This review will summarize work that highlights the importance of considering oxygen conditions for culturing and manipulating stem cells. Emphasis is placed on major phenotypic changes in response to oxygen, recognizing that oxygen-mediated transcriptional and post-translational effects are enormously complex, and beyond the scope of this review. The review emphasizes that oxygen is an important signal in all major aspects of stem cell biology including proliferation and tumorigenesis, cell death and differentiation, self-renewal, and migration.
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Affiliation(s)
- Marie Csete
- Emory Anesthesiology Research Labs, 1462 Clifton Rd. N.E., Room 420, Atlanta, GA 30322, USA.
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14
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López-Soriano J, Chiellini C, Maffei M, Grimaldi PA, Argilés JM. Roles of skeletal muscle and peroxisome proliferator-activated receptors in the development and treatment of obesity. Endocr Rev 2006; 27:318-29. [PMID: 16556851 DOI: 10.1210/er.2005-0012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Metabolic disturbances associated with alterations in lipid metabolism, such as obesity, type 2 diabetes, and syndrome X, are becoming more and more prominent in Western societies. Despite extensive research in such pathologies and their molecular basis, we are still far from completely understanding how these metabolic perturbations are produced and interrelate and, consequently, how to treat them efficiently. The discovery that adipose tissue is, in fact, an endocrine tissue able to secrete active molecules related to lipid homeostasis--the adipokines--has dramatically changed our understanding of the molecular events that take place in such diseases. This knowledge has been further improved by the discovery of peroxisome proliferator-activated receptors and their ligands, at present commonly used for the clinical treatment of lipid disturbances. However, a key point remains to be solved, and that is the role of muscle lipid metabolism, notably because of the main role played by this tissue in the development of such pathologies. In addition, a reciprocal regulation between adipose tissue and skeletal muscle has been proposed. New discoveries on the role of peroxisome proliferator-activated receptor-delta in skeletal muscle functions as well as the secretory capabilities of muscle, now considered as an endocrine tissue, have changed the general point of view on lipid homeostasis, opening new and promising doors for the treatment of lipid disorders.
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Affiliation(s)
- Joaquín López-Soriano
- Department of Endocrinology and Metabolism, Ospedale di Cisanello, University of Pisa, Italy
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15
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Coyle AT, Kinsella BT. Synthetic peroxisome proliferator-activated receptor γ agonists rosiglitazone and troglitazone suppress transcription by promoter 3 of the human thromboxane A2 receptor gene in human erythroleukemia cells. Biochem Pharmacol 2006; 71:1308-23. [PMID: 16499875 DOI: 10.1016/j.bcp.2006.01.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 01/20/2006] [Accepted: 01/20/2006] [Indexed: 10/25/2022]
Abstract
The human thromboxane (TX)A2 receptor (TP) gene encodes two TP isoforms, TPalpha and TPbeta, that are regulated by distinct promoters designated promoter Prm1 and Prm3, respectively. Previous studies established that 15d-Delta12,14-prostaglandin J2 (15d-PGJ2) selectively inhibits Prm3 activity and TPbeta expression through a peroxisome proliferator-activated receptor (PPAR)gamma mechanism without affecting Prm1 activity or TPalpha expression in human megakaryocytic erythroleukemia (HEL) 92.1.7 cells. Herein, we investigated the effect of synthetic thiazolidinedione (TZD) PPARgamma ligands rosiglitazone and troglitazone on TP gene expression in HEL cells. Like 15d-PGJ2, both TZDs suppressed Prm3 activity, TPbeta mRNA expression and TP-mediated calcium mobilization without affecting Prm1 or TPalpha mRNA expression. However, unlike 15d-PGJ2, both TZDs mediated their PPARgamma-dependent effects through trans-repression of an activator protein-1 (AP-1) element, a site previously found to be critical for basal Prm3 activity. These data provide further evidence for the role of PPARgamma in regulating the human TP gene; they highlight further differences in TPalpha and TPbeta expression/regulation and point to essential differences between natural and synthetic PPARgamma agonists in mediating those effects.
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MESH Headings
- Cell Line
- Cell Line, Tumor
- Chromans/pharmacology
- Genes, Reporter
- Humans
- Leukemia, Erythroblastic, Acute
- Luciferases
- PPAR gamma/agonists
- Promoter Regions, Genetic/genetics
- Prostaglandin D2/analogs & derivatives
- Prostaglandin D2/pharmacology
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- RNA, Messenger/metabolism
- Receptors, Thromboxane A2, Prostaglandin H2/genetics
- Receptors, Thromboxane A2, Prostaglandin H2/metabolism
- Retinoid X Receptor alpha
- Rosiglitazone
- Thiazolidinediones/pharmacology
- Transcription Factor AP-1
- Transcription, Genetic
- Troglitazone
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Affiliation(s)
- Adrian T Coyle
- School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
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16
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Bondesen BA, Mills ST, Pavlath GK. The COX-2 pathway regulates growth of atrophied muscle via multiple mechanisms. Am J Physiol Cell Physiol 2006; 290:C1651-9. [PMID: 16467402 DOI: 10.1152/ajpcell.00518.2005] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Loss of muscle mass occurs with disease, injury, aging, and inactivity. Restoration of normal muscle mass depends on myofiber growth, the regulation of which is incompletely understood. Cyclooxygenase (COX)-2 is one of two isoforms of COX that catalyzes the synthesis of prostaglandins, paracrine hormones that regulate diverse physiological and pathophysiological processes. Previously, we demonstrated that the COX-2 pathway regulates early stages of myofiber growth during muscle regeneration. However, whether the COX-2 pathway plays a common role in adult myofiber growth or functions specifically during muscle regeneration is unknown. Therefore, we examined the role of COX-2 during myofiber growth following atrophy in mice. Muscle atrophy was induced by hindlimb suspension (HS) for 2 wk, followed by a reloading period, during which mice were treated with either the COX-2-selective inhibitor SC-236 (6 mg x kg(-1) x day(-1)) or vehicle. COX-2 protein was expressed and SC-236 attenuated myofiber growth during reloading in both soleus and plantaris muscles. Attenuated myofiber growth in the soleus was associated with both decreased myonuclear addition and decreased inflammation, whereas neither of these processes mediated the effects of SC-236 on plantaris growth. In addition, COX-2(-/-) satellite cells exhibited impaired activation/proliferation in vitro, suggesting direct regulation of muscle cell activity by COX-2. Together, these data suggest that the COX-2 pathway plays a common regulatory role during various types of muscle growth via multiple mechanisms.
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Affiliation(s)
- Brenda A Bondesen
- Emory Univ. School of Medicine, Dept. of Pharmacology, O. W. Rollins Research Bldg., Atlanta, GA 30322, USA
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17
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McFarlane C, Plummer E, Thomas M, Hennebry A, Ashby M, Ling N, Smith H, Sharma M, Kambadur R. Myostatin induces cachexia by activating the ubiquitin proteolytic system through an NF-κB-independent, FoxO1-dependent mechanism. J Cell Physiol 2006; 209:501-14. [PMID: 16883577 DOI: 10.1002/jcp.20757] [Citation(s) in RCA: 326] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Myostatin, a transforming growth factor-beta (TGF-beta) super-family member, has been well characterized as a negative regulator of muscle growth and development. Myostatin has been implicated in several forms of muscle wasting including the severe cachexia observed as a result of conditions such as AIDS and liver cirrhosis. Here we show that Myostatin induces cachexia by a mechanism independent of NF-kappaB. Myostatin treatment resulted in a reduction in both myotube number and size in vitro, as well as a loss in body mass in vivo. Furthermore, the expression of the myogenic genes myoD and pax3 was reduced, while NF-kappaB (the p65 subunit) localization and expression remained unchanged. In addition, promoter analysis has confirmed Myostatin inhibition of myoD and pax3. An increase in the expression of genes involved in ubiquitin-mediated proteolysis is observed during many forms of muscle wasting. Hence we analyzed the effect of Myostatin treatment on proteolytic gene expression. The ubiquitin associated genes atrogin-1, MuRF-1, and E214k were upregulated following Myostatin treatment. We analyzed how Myostatin may be signaling to induce cachexia. Myostatin signaling reversed the IGF-1/PI3K/AKT hypertrophy pathway by inhibiting AKT phosphorylation thereby increasing the levels of active FoxO1, allowing for increased expression of atrophy-related genes. Therefore, our results suggest that Myostatin induces cachexia through an NF-kappaB-independent mechanism. Furthermore, increased Myostatin levels appear to antagonize hypertrophy signaling through regulation of the AKT-FoxO1 pathway.
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Affiliation(s)
- Craig McFarlane
- AgResearch, Functional Muscle Genomics, East Street, Hamilton, New Zealand
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18
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Abstract
The adipocyte has pleiotropic functions beyond the storage of energy in times of nutrient abundance. Considerable efforts in adipocyte biology within the past ten years have emphasized the important role of adipose tissue in processes as diverse as energy metabolism, inflammation and cancer. Adipocytes are able to communicate with the brain and peripheral tissues implementing metabolic signals such as satiety, food intake and energy expenditure. Despite its huge pharmacological potential, only a small number of clinical applications interfere directly with adipocyte physiology. Here, we want to highlight various areas of adipocyte physiology that have not yet been explored pharmacologically and emphasize some of the limitations associated with these pharmacotherapies.
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Affiliation(s)
- Andrea R Nawrocki
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA
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19
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Schwab AM, Granholm S, Persson E, Wilkes B, Lerner UH, Conaway HH. Stimulation of resorption in cultured mouse calvarial bones by thiazolidinediones. Endocrinology 2005; 146:4349-61. [PMID: 15994344 DOI: 10.1210/en.2005-0601] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Dosage-dependent release of 45Ca was observed from prelabeled mouse calvarial bones after treatment with two thiazolidinediones, troglitazone and ciglitazone. Release of 45Ca by ciglitazone was decreased by the osteoclast inhibitors acetazolamide, calcitonin, 3-amino-1-hydroxypropylidene-1,1-bisphosphonate, and IL-4, but not affected by the peroxisome proliferator-activated receptor gamma antagonist, GW 9662, the mitotic inhibitor, hydroxyurea, or indomethacin. Enhanced expression of receptor activator of nuclear factor-kappaB ligand (RANKL) mRNA and protein and decreased osteoprotegerin (OPG) mRNA and protein were noted after ciglitazone treatment of calvariae. Ciglitazone and RANKL each caused increased mRNA expression of osteoclast markers: calcitonin receptor, tartrate-resistant acid phosphatase, cathepsin K, matrix metalloproteinase-9, integrin beta3, and nuclear factor of activated T cells 2. OPG inhibited mRNA expression of RANKL stimulated by ciglitazone, mRNA expression of osteoclast markers stimulated by ciglitazone and RANKL, and 45Ca release stimulated by troglitazone and ciglitazone. Increased expression of IL-1alpha mRNA by ciglitazone was not linked to resorption stimulated by the thiazolidinedione. Ciglitazone did not increase adipogenic gene expression but enhanced osteocalcin mRNA in calvariae. In addition to exhibiting sensitivity to OPG, data indicate that stimulation of osteoclast differentiation and activity by thiazolidinediones may occur by a nonperoxisome proliferator-activated receptor gamma-dependent pathway that does not require cell proliferation, prostaglandins, or IL-1alpha but is characterized by an increased RANKL to OPG ratio.
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Affiliation(s)
- A M Schwab
- Department of Physiology and Biophysics, University of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 505, Little Rock, Arkansas 72205, USA
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20
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Patel H, Truant R, Rachubinski RA, Capone JP. Activity and subcellular compartmentalization of peroxisome proliferator-activated receptor alpha are altered by the centrosome-associated protein CAP350. J Cell Sci 2005; 118:175-86. [PMID: 15615782 DOI: 10.1242/jcs.01600] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peroxisome proliferator-activated nuclear hormone receptors (PPAR) are ligand-activated transcription factors that play pivotal roles in governing metabolic homeostasis and cell growth. PPARs are primarily in the nucleus but, under certain circumstances, can be found in the cytoplasm. We show here that PPAR(alpha) interacts with the centrosome-associated protein CAP350. CAP350 also interacts with PPAR(delta), PPAR(gamma) and liver-X-receptor alpha, but not with the 9-cis retinoic acid receptor, RXR(alpha). Immunofluorescence analysis indicated that PPAR(alpha) is diffusely distributed in the nucleus and excluded from the cytoplasm. However, in the presence of coexpressed CAP350, PPAR(alpha) colocalizes with CAP350 to discrete nuclear foci and to the centrosome, perinuclear region and intermediate filaments. In contrast, the subcellular distribution of RXR(alpha) or of thyroid hormone receptor alpha was not altered by coexpression of CAP350. An amino-terminal fragment of CAP350 was localized exclusively to nuclear foci and was sufficient to recruit PPAR(alpha) to these sites. Mutation of the single putative nuclear hormone receptor interacting signature motif LXXLL present in this fragment had no effect on its subnuclear localization but abrogated recruitment of PPAR(alpha) to nuclear foci. Surprisingly, mutation of the LXXLL motif in this CAP350 subfragment did not prevent its binding to PPAR(alpha) in vitro, suggesting that this motif serves some function other than PPAR(alpha) binding in recruiting PPAR(alpha) to nuclear spots. CAP350 inhibited PPAR(alpha)-mediated transactivation in an LXXLL-dependent manner, suggesting that CAP350 represses PPAR(alpha) function. Our findings implicate CAP350 in a dynamic process that recruits PPAR(alpha) to discrete nuclear and cytoplasmic compartments and suggest that altered intracellular compartmentalization represents a regulatory process that modulates PPAR function.
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Affiliation(s)
- Hansa Patel
- Department of Biochemistry, McMaster University, Hamilton, ON L8N 3Z5, Canada
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21
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Yun Z, Lin Q, Giaccia AJ. Adaptive myogenesis under hypoxia. Mol Cell Biol 2005; 25:3040-55. [PMID: 15798192 PMCID: PMC1069592 DOI: 10.1128/mcb.25.8.3040-3055.2005] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2004] [Revised: 08/24/2004] [Accepted: 01/18/2005] [Indexed: 01/03/2023] Open
Abstract
Previous studies have indicated that myoblasts can differentiate and repair muscle injury after an ischemic insult. However, it is unclear how hypoxia or glucose deprivation in the ischemic microenvironment affects myoblast differentiation. We have found that myogenesis can adapt to hypoxic conditions. This adaptive mechanism is accompanied by initial inhibition of the myoD, E2A, and myogenin genes followed by resumption of their expression in an oxygen-dependent manner. The regulation of myoD transcription by hypoxia is correlated with transient deacetylation of histones associated with the myoD promoter. It is noteworthy that, unlike the differentiation of other cell types such as preadipocytes or chondroblasts, the effect of hypoxia on myogenesis is independent of HIF-1, a ubiquitous regulator of transcription under hypoxia. While myogenesis can also adapt to glucose deprivation, the combination of severe hypoxia and glucose deprivation found in an ischemic environment results in pronounced loss of myoblasts. Our studies indicate that the ischemic muscle can be repaired via the adaptive differentiation of myogenic precursors, which depends on the levels of oxygen and glucose in the ischemic microenvironment.
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MESH Headings
- Acetylation
- Adaptation, Physiological
- Animals
- Basic Helix-Loop-Helix Transcription Factors
- Cell Differentiation
- Cell Hypoxia
- Cell Line
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- DNA-Binding Proteins/physiology
- Down-Regulation
- Energy Metabolism/genetics
- Energy Metabolism/physiology
- Gene Expression Regulation, Developmental
- Glucose/metabolism
- Histones/metabolism
- Hypoxia-Inducible Factor 1
- Hypoxia-Inducible Factor 1, alpha Subunit
- Mice
- Muscle Development/genetics
- Muscle Development/physiology
- MyoD Protein/genetics
- MyoD Protein/metabolism
- Myoblasts/metabolism
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- Myogenin/genetics
- Myogenin/metabolism
- Nuclear Proteins/genetics
- Nuclear Proteins/physiology
- Oxygen/metabolism
- Oxygen/pharmacology
- Promoter Regions, Genetic/drug effects
- Promoter Regions, Genetic/genetics
- RNA Stability
- RNA, Messenger/analysis
- RNA, Messenger/metabolism
- Sequence Deletion
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transcription Factors/physiology
- Transcription, Genetic
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Affiliation(s)
- Zhong Yun
- Department of Radiation Oncology, Stanford University School of Medicine, 269 Campus Dr., CCSR-1250, Stanford, CA 94305, USA.
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22
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Tascou S, Sorensen TK, Glénat V, Wang M, Lakich MM, Darteil R, Vigne E, Thuillier V. Stringent rosiglitazone-dependent gene switch in muscle cells without effect on myogenic differentiation. Mol Ther 2004; 9:637-49. [PMID: 15120324 DOI: 10.1016/j.ymthe.2004.02.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2003] [Accepted: 02/19/2004] [Indexed: 01/22/2023] Open
Abstract
We have developed a gene switch based on the human transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma) and its activation by rosiglitazone. However, ectopic expression of PPARgamma has been demonstrated to convert myogenic cells into adipocyte-like cells and, more generally, may interfere with the physiology of the target tissue. Consequently we modified the DNA-binding specificity of PPARgamma, resulting in a transcription factor that we named PPAR*. We demonstrated by histological and molecular assessment of cell phenotype that the overexpression of PPAR* did not alter the myogenic differentiation program of G8 myoblasts. We showed that PPAR* does not transactivate promoters containing PPARgamma-responsive elements but transactivates promoters containing PPAR*-responsive elements that are at least 80% identical to a 20-bp consensus. We improved the rosiglitazone-dependent gene switch by tuning PPAR* expression with a scaffold/matrix attachment region and by expressing both PPAR* and the reporter gene under the control of PPAR*-responsive elements. Treatment of cultured murine muscle cells (myotubes) with rosiglitazone induced reporter gene expression from assay background up to the level attained by a CMV I/E promoter-enhancer. These results indicate the potential of the PPAR* gene switch for use in gene therapy applications.
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Affiliation(s)
- Semi Tascou
- Gencell S.A.S., 72-82 Rue Léon Geoffroy, 94408 Vitry sur Seine, France
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23
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Verma NK, Singh J, Dey CS. PPAR-gamma expression modulates insulin sensitivity in C2C12 skeletal muscle cells. Br J Pharmacol 2004; 143:1006-13. [PMID: 15504754 PMCID: PMC1575957 DOI: 10.1038/sj.bjp.0706002] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2004] [Revised: 08/23/2004] [Accepted: 09/08/2004] [Indexed: 11/09/2022] Open
Abstract
Peroxisome proliferator-activated receptor-gamma (PPAR-gamma) expression is very low in skeletal muscle cells, which is one of the most important target tissues for insulin and plays a predominant role in glucose homeostasis. It has recently been shown that muscle-specific PPAR-gamma deletion in mouse causes insulin resistance. However, it is likely that the observed effects might be due to secondary interaction in whole animal. The aim of the study was to explore the role of muscle PPAR-gamma in insulin sensitivity. We stably transfected C2C12 skeletal muscle cells with plasmids containing sense or antisense constructs of PPAR-gamma and examined the effect of modulation of PPAR-gamma expression in terms of glucose uptake. Effect was also examined in insulin-resistant C2C12 skeletal muscle cells. In transfected C2C12 cell line, the inhibition of PPAR-gamma expression (23.0 +/-0.005%) was observed to induce insulin resistance as determined by functional assessment of 2-deoxyglucose incorporation. Overexpression of PPAR-gamma (28.5 +/- 0.008%) produced an additional effect on insulin (100 nM) and Pioglitazone (50 microM), resulting in 42.7 +/- 3.5% increase in glucose uptake as against 29.2+/-2.8% in wild-type C2C12 skeletal muscle cells differentiated under normal (2% horse serum) condition. Under similar treatment, PPAR-gamma overexpressing cells resistant to insulin exhibited enhanced glucose uptake upto 60.7 +/- 4.08%, as compared to 23.8 +/- 5.1% observed in wild-type C2C12 skeletal muscle cells. These data demonstrate a direct involvement of PPAR-gamma in insulin sensitization of TZD action on skeletal muscle cells, and suggest that pharmacological overexpression of muscle PPAR-gamma gene in skeletal muscle might be a useful strategy for the treatment of insulin resistance.
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Affiliation(s)
- Navin K Verma
- Signal Transduction Research Laboratory, Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Punjab 160 062, India
| | - Jaskirat Singh
- Signal Transduction Research Laboratory, Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Punjab 160 062, India
| | - Chinmoy S Dey
- Signal Transduction Research Laboratory, Department of Biotechnology, National Institute of Pharmaceutical Education and Research (NIPER), Sector 67, S.A.S. Nagar, Punjab 160 062, India
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24
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Larsson O, Scheele C, Liang Z, Moll J, Karlsson C, Wahlestedt C. Kinetics of senescence-associated changes of gene expression in an epithelial, temperature-sensitive SV40 large T antigen model. Cancer Res 2004; 64:482-9. [PMID: 14744760 DOI: 10.1158/0008-5472.can-03-1872] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Replicative senescence limits the number of times primary cells can divide and is therefore regarded as a potential checkpoint for cancer progression. The majority of studies examining changes of gene expression upon senescence have been made with stationary senescent cells. We wanted to study the transition from normal growth to senescence in detail and identify early regulators of senescence by analyzing early changes in global gene expression, using Affymetrix microarrays. For this purpose, we used a murine epithelial senescence model, where senescence is abrogated by SV40 large T antigen and can be induced by using a temperature-sensitive form of SV40 large T antigen (SV40ts58). Comparisons were made to wild-type SV40 large T antigen-expressing cells and to cells expressing SV40ts58 large T antigen grown to confluence. After removal of genes that are similarly regulated in wild-type and temperature-sensitive SV40 large T antigen-expressing cells, 60% of the remaining genes were shared between cells arrested by inactivation of SV40 T antigen and by confluence. We identified 125 up-regulated and 39 down-regulated candidate genes/expressed sequence tags that are regulated upon SV40 T antigen inactivation and not during heat shock or confluence and classified these based on their kinetic profiles. Our study identified genes that fall into different functional clusters, such as transforming growth factor-beta-related genes and transcription factors, and included genes not identified previously as senescence associated. The genes are candidates as early regulators of the senescence checkpoint and may be potential molecular targets for novel anticancer drugs.
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Affiliation(s)
- Ola Larsson
- Center for Genomics and Bioinformatics and. Department of Cell and Molecular Biology, Karolinska Institutet, Stockholm, Sweden.
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25
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Worley JR, Baugh MD, Hughes DA, Edwards DR, Hogan A, Sampson MJ, Gavrilovic J. Metalloproteinase expression in PMA-stimulated THP-1 cells. Effects of peroxisome proliferator-activated receptor-gamma (PPAR gamma) agonists and 9-cis-retinoic acid. J Biol Chem 2003; 278:51340-6. [PMID: 14534304 DOI: 10.1074/jbc.m310865200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The PPAR gamma agonists, thiazolidinediones (TZDs), have anti-inflammatory properties as well as increasing insulin sensitivity. This has widened their therapeutic scope to treat inflammatory diseases such as atherosclerosis in addition to Type 2 Diabetes. TZDs are known to reduce monocyte/macrophage expression of Matrix metalloproteinase (MMP)-9, which is implicated in atherosclerotic plaque destabilization. This study aims to identify other metalloproteinase genes of the ADAM (A Disintegin And Metalloproteinase) and ADAMTS families that are regulated by PPAR gamma or RXR agonists, which are potentially important in type 2 diabetes and/or related atherosclerosis. The synthetic PPAR gamma agonist, GW7845, and the natural agonist 15d-PGJ2, suppressed PMA stimulated MMP-9 in human monocyte-like cells (THP-1) only in the presence of 9-cis-retinoic acid. Quantitative Real-Time PCR showed that this reduction was regulated at the mRNA level. Expression of ADAMs 8, 9, and 17 were increased, and ADAM15 was decreased by stimulation of THP-1 with PMA, although these ADAMs were not regulated by PPAR gamma or RXR agonists. PMA-induced ADAM28 expression was further enhanced by the addition of 9-cis-retinoic acid. ADAMTS4, implicated in rheumatoid arthritis, was expressed in THP-1 cells, and significantly increased after 24 h of PMA stimulation. ADAMTS4 expression was suppressed by both PPAR gamma and RXR agonists and was undetectable when the agonists were combined. Pretreatment of THP-1 cells with the PPAR gamma antagonist, GW9662, suggests that PPAR gamma plays subtly different roles in the regulation of MMP-9, ADAMTS4 and ADAM28 gene expression. These results indicate that PPAR gamma and RXR agonists have complex effects on monocyte metalloproteinase expression, which may have implications for therapeutic strategies.
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Affiliation(s)
- Joanna R Worley
- School of Biological Sciences, University of East Anglia, and Bertram Diabetes Research Unit, Norfolk & Norwich University Hospital NHS Trust, Norwich, United Kingdom
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26
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Dressel U, Allen TL, Pippal JB, Rohde PR, Lau P, Muscat GEO. The peroxisome proliferator-activated receptor beta/delta agonist, GW501516, regulates the expression of genes involved in lipid catabolism and energy uncoupling in skeletal muscle cells. Mol Endocrinol 2003; 17:2477-93. [PMID: 14525954 DOI: 10.1210/me.2003-0151] [Citation(s) in RCA: 299] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Lipid homeostasis is controlled by the peroxisome proliferator-activated receptors (PPARalpha, -beta/delta, and -gamma) that function as fatty acid-dependent DNA-binding proteins that regulate lipid metabolism. In vitro and in vivo genetic and pharmacological studies have demonstrated PPARalpha regulates lipid catabolism. In contrast, PPARgamma regulates the conflicting process of lipid storage. However, relatively little is known about PPARbeta/delta in the context of target tissues, target genes, lipid homeostasis, and functional overlap with PPARalpha and -gamma. PPARbeta/delta, a very low-density lipoprotein sensor, is abundantly expressed in skeletal muscle, a major mass peripheral tissue that accounts for approximately 40% of total body weight. Skeletal muscle is a metabolically active tissue, and a primary site of glucose metabolism, fatty acid oxidation, and cholesterol efflux. Consequently, it has a significant role in insulin sensitivity, the blood-lipid profile, and lipid homeostasis. Surprisingly, the role of PPARbeta/delta in skeletal muscle has not been investigated. We utilize selective PPARalpha, -beta/delta, -gamma, and liver X receptor agonists in skeletal muscle cells to understand the functional role of PPARbeta/delta, and the complementary and/or contrasting roles of PPARs in this major mass peripheral tissue. Activation of PPARbeta/delta by GW501516 in skeletal muscle cells induces the expression of genes involved in preferential lipid utilization, beta-oxidation, cholesterol efflux, and energy uncoupling. Furthermore, we show that treatment of muscle cells with GW501516 increases apolipoprotein-A1 specific efflux of intracellular cholesterol, thus identifying this tissue as an important target of PPARbeta/delta agonists. Interestingly, fenofibrate induces genes involved in fructose uptake, and glycogen formation. In contrast, rosiglitazone-mediated activation of PPARgamma induces gene expression associated with glucose uptake, fatty acid synthesis, and lipid storage. Furthermore, we show that the PPAR-dependent reporter in the muscle carnitine palmitoyl-transferase-1 promoter is directly regulated by PPARbeta/delta, and not PPARalpha in skeletal muscle cells in a PPARgamma coactivator-1-dependent manner. This study demonstrates that PPARs have distinct roles in skeletal muscle cells with respect to the regulation of lipid, carbohydrate, and energy homeostasis. Moreover, we surmise that PPARbeta/delta agonists would increase fatty acid catabolism, cholesterol efflux, and energy expenditure in muscle, and speculate selective activators of PPARbeta/delta may have therapeutic utility in the treatment of hyperlipidemia, atherosclerosis, and obesity.
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Affiliation(s)
- Uwe Dressel
- Institute Molecular Bioscience, St. Lucia, Queensland 4072, Australia.
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27
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Mendez M, LaPointe MC. PPARgamma inhibition of cyclooxygenase-2, PGE2 synthase, and inducible nitric oxide synthase in cardiac myocytes. Hypertension 2003; 42:844-50. [PMID: 12885795 DOI: 10.1161/01.hyp.0000085332.69777.d1] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors belonging to the nuclear receptor superfamily. They regulate lipid metabolism, glucose homeostasis, cell proliferation, and differentiation and modulate inflammatory responses. We examined whether PPARgamma is functional in cultured neonatal ventricular myocytes and studied its role in inflammation. Western blots revealed PPARgamma in myocytes. When myocytes were transfected with a PPAR response element reporter plasmid (PPRE-TK-luciferase), the PPARgamma activator 15-deoxy-Delta12,14-prostaglandin J2 (15dPGJ2) increased promoter activity, whereas cotransfection of a dominant negative PPARgamma inhibited it. To determine the role of 15dPGJ2 in expression of proinflammatory genes, we tested its effect on interleukin-1beta induction of cyclooxygenase-2 (COX-2). 15dPGJ2 decreased interleukin-1beta stimulation of COX-2 by 40% and PGE2 production by 73%. We next questioned whether 15dPGJ2 was modulating the expression of inducible prostaglandin E2 synthase (PGES) and found that it completely blocked interleukin-1beta induction of PGES. Use of a second PPARgamma agonist, troglitazone, and the selective PPARgamma antagonist GW9662 demonstrated that the effects seen were PPARgamma-dependent. In addition, we found that 15dPGJ2 blocked interleukin-1beta stimulation of inducible nitric oxide synthase (iNOS). We concluded that 15dPGJ2 may play an anti-inflammatory role in a PPARgamma-dependent manner, decreasing COX-2, PGES, and PGE2 production, as well as iNOS expression.
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Affiliation(s)
- Mariela Mendez
- Hypertension and Vascular Research Division, Henry Ford Hospital, 2799 West Grand Blvd, Detroit, MI 48202-2689, USA
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28
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Ghosh SS, Gehr TWB, Ghosh S, Fakhry I, Sica DA, Lyall V, Schoolwerth AC. PPARgamma ligand attenuates PDGF-induced mesangial cell proliferation: role of MAP kinase. Kidney Int 2003; 64:52-62. [PMID: 12787395 DOI: 10.1046/j.1523-1755.2003.00054.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Mesangial proliferation is a key feature in the pathogenesis of a number of renal diseases and can be experimentally induced by the mitogen platelet-derived growth factor (PDGF). Mitogen-activated protein kinase (MAPK) signaling plays a key role in mesangial cell proliferation. In the present study we examined whether peroxisome proliferator-activated receptor gamma (PPARgamma) activators/ligands, thiazolidinediones such as ciglitazone, troglitazone, and rosiglitazone, can inhibit cell proliferation by modulating individual steps in the MAPK pathway. METHODS Mouse mesangial cells were made quiescent and proliferation was measured following the application of PDGF. Using ciglitazone as the model compound, the mechanism of the antiproliferative effect of PPARgamma activators on MAPK and specific cell cycle regulatory proteins were examined by Western blot analysis and transfection studies. RESULTS Ciglitazone inhibited PDGF-induced mesangial cell proliferation in a dose-dependent manner (1 to 20 micromol/L). The inhibitory effect was blocked by a peroxisome proliferator-activated receptor element (PPRE) decoy oligonucleotide, indicating that the observed effect of ciglitazone was via PPARgamma activation. Ciglitazone (1 to 20 micromol/L) did not affect extracellular signal-regulated protein kinase (ERK) activation but inhibited the activation of serum response element (SRE) by 85 +/- 6% (P < 0.01). This effect was associated with a reduction in c-fos expression (80 +/- 9%, P < 0.01). Ciglitazone (1, 10, and 20 micromol/L) also inhibited cyclin D1 expression by 37 +/- 8%, 79 +/- 15%, and 87 +/- 12%, respectively (P < 0.001 to 0.001), and p21 expression by 45 +/- 6% (P < 0.01), 61 +/- 10% (P < 0.001), and 72 +/- 8% (P < 0.001), respectively. Ciglitazone inhibited PDGF-mediated up-regulation of p27. In addition, the antiproliferative effect of ciglitazone was potentiated by PD98059, a mitogen-activated protein (MAP) kinase kinase (MEK) inhibitor that acts at a step upstream from ERK. CONCLUSION These data indicate that PPARgamma activation may inhibit mesangial growth directly by affecting MAPK and cell cycle regulatory proteins. Furthermore, a MAP kinase inhibitor can potentiate the antiproliferative effect.
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Affiliation(s)
- Siddhartha S Ghosh
- Division of Nephrology, MCV Campus, Virginia Commonwealth University, Richmond, Virginia 23298, USA
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29
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Smith SA, Monteith GR, Holman NA, Robinson JA, May FJ, Roberts-Thomson SJ. Effects of peroxisome proliferator-activated receptor gamma ligands ciglitazone and 15-deoxy-delta 12,14-prostaglandin J2 on rat cultured cerebellar granule neuronal viability. J Neurosci Res 2003; 72:747-55. [PMID: 12774315 DOI: 10.1002/jnr.10613] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) has been the focus of studies assessing its potential neuroprotective role. These studies have shown either neuroprotection or neurotoxicity by PPARgamma ligands. Comparison of these studies is complicated by the use of different PPARgamma ligands, mechanisms of neurotoxicity induction, and neuronal cell type. In this study, we compared the effects of the synthetic PPARgamma ligand ciglitazone with an endogenous PPARgamma ligand, 15-deoxy-delta(12,14)-prostaglandin J(2) (15-deoxy PGJ(2)), on inherent neurotoxicity and neuroprotection using a reduction in extracellular KCl in rat cultured cerebellar granule neurons (CGN). We also assessed the effects of these ligands on c-Jun protein expression, which is up-regulated on induction of low-KCl-mediated neuronal apoptosis as well as being associated with PPAR in other cell types. We showed that PPARgamma mRNA is expressed in CGN cultures and observed ciglitazone- and 15-deoxy PGJ(2)-mediated inherent neurotoxicity that was concentration and time dependent. c-Jun was only modestly increased in the presence of ciglitazone but was markedly up-regulated by 15-deoxy PGJ(2) after 12 hr. Treatment of CGN cultures with ciglitazone simultaneous with KCl withdrawal resulted in a modest, time-dependent neuroprotection. Such neuroprotection after KCl withdrawal was not observed with 15-deoxy PGJ(2). Despite the absence of neuroprotection, 15-deoxy PGJ(2) markedly inhibited the early up-regulation of c-Jun during KCl withdrawal. These studies suggest that ciglitazone and 15-deoxy PGJ(2) have markedly different effects on inherent and low-KCl-induced toxicity and c-Jun expression in CGN, indicating potential non-PPARgamma mechanisms.
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Affiliation(s)
- Steven A Smith
- School of Pharmacy, The University of Queensland, St. Lucia, Queensland, Australia
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Yee LD, Guo Y, Bradbury J, Suster S, Clinton SK, Seewaldt VL. The antiproliferative effects of PPARgamma ligands in normal human mammary epithelial cells. Breast Cancer Res Treat 2003; 78:179-92. [PMID: 12725418 DOI: 10.1023/a:1022978608125] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) is a transcription factor in the steroid nuclear receptor superfamily. Ligand activation of PPARgamma is associated with differentiation and an inhibition of proliferation in normal and malignant cells, including adipocytes, monocytes, and tumor cells in colon, prostate, and breast cancers. The current studies were undertaken to assess both the expression and functional activity of PPARgamma in cultured normal human mammary epithelial cells (HMECs) and tissue samples. Analyses by northern hybridization, immunoblotting, and immunohistochemistry demonstrate PPARgamma gene expression in HMECs and breast tissue specimens. DNA binding and transactivation assays indicate the presence of functionally active PPARgamma in HMECs. Treatment with PPARgamma selective ligands, 15-deoxy-delta-(12,14)-prostaglandin J2 (15dPGJ2) and ciglitazone, inhibits the growth of HMECs in a dose-dependent manner. This growth inhibition is associated with alterations in cell cycle progression and the induction of apoptosis.
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Affiliation(s)
- Lisa D Yee
- Department of Surgery, The Ohio State University, Columbus, OH 43210, USA.
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Sasao N, Hirayama E, Kim J. Characterization of heterokaryons between skeletal myoblasts and preadipocytes: myogenic potential of 3T3-L1 preadipocytes. Eur J Cell Biol 2003; 82:97-103. [PMID: 12647936 DOI: 10.1078/0171-9335-00299] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has been shown previously that heterokaryons between myoblasts and non-myogenic cells disturb myogenic differentiation (Hirayama et al. (2001); Cell Struct. Funct. 26, 37-47), suggesting that some myogenesis inhibitory factors exist in non-myogenic cells. Skeletal myoblasts and adipose cells are derived from a common mesodermal stem cell, indicating that both cells have a closer relationship in the developmental lineage than the other somatic cells. To investigate the functional relationship between myoblasts and adipose cells, heterokaryons between quail myoblasts and 3T3-L1 cells, a mouse preadipocyte cell line, were prepared and examined for characteristics of myogenic differentiation. Myogenic differentiation was inhibited in the heterokaryons between quail myoblasts and well-differentiated (adipocytes) 3T3-L1 cells. On the contrary, normal myogenic differentiation proceeded in the heterokaryons between quail myoblasts and undifferentiated (preadipocytes) 3T3-L1 cells. Further investigation showed that the mouse myogenin gene from 3T3-L1 cells was transactivated in the heterokaryons between quail myoblasts and undifferentiated 3T3-L1 cells. The results demonstrated that undifferentiated 3T3-L1 cells have no myogenesis inhibitory factors but acquire these during terminal differentiation into adipocytes.
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Affiliation(s)
- Nagako Sasao
- Institute of Molecular and Cellular Biology for Pharmaceutical Sciences, Kyoto Pharmaceutical University, Misasagi, Kyoto, Japan
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Langley B, Thomas M, Bishop A, Sharma M, Gilmour S, Kambadur R. Myostatin inhibits myoblast differentiation by down-regulating MyoD expression. J Biol Chem 2002; 277:49831-40. [PMID: 12244043 DOI: 10.1074/jbc.m204291200] [Citation(s) in RCA: 613] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Myostatin, a negative regulator of myogenesis, is shown to function by controlling the proliferation of myoblasts. In this study we show that myostatin is an inhibitor of myoblast differentiation and that this inhibition is mediated through Smad 3. In vitro, increasing concentrations of recombinant mature myostatin reversibly blocked the myogenic differentiation of myoblasts, cultured in low serum media. Western and Northern blot analysis indicated that addition of myostatin to the low serum culture media repressed the levels of MyoD, Myf5, myogenin, and p21 leading to the inhibition of myogenic differentiation. The transient transfection of C(2)C(12) myoblasts with MyoD expressing constructs did not rescue myostatin-inhibited myogenic differentiation. Myostatin signaling specifically induced Smad 3 phosphorylation and increased Smad 3.MyoD association, suggesting that Smad 3 may mediate the myostatin signal by interfering with MyoD activity and expression. Consistent with this, the expression of dominant-negative Smad3 rescued the activity of a MyoD promoter-reporter in C(2)C(12) myoblasts treated with myostatin. Taken together, these results suggest that myostatin inhibits MyoD activity and expression via Smad 3 resulting in the failure of the myoblasts to differentiate into myotubes. Thus we propose that myostatin plays a critical role in myogenic differentiation and that the muscular hyperplasia and hypertrophy seen in animals that lack functional myostatin is because of deregulated proliferation and differentiation of myoblasts.
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Affiliation(s)
- Brett Langley
- Animal Genomics, AgResearch, Private Bag 3123, East Street, Hamilton, New Zealand
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Pontsler AV, St Hilaire A, Marathe GK, Zimmerman GA, McIntyre TM. Cyclooxygenase-2 is induced in monocytes by peroxisome proliferator activated receptor gamma and oxidized alkyl phospholipids from oxidized low density lipoprotein. J Biol Chem 2002; 277:13029-36. [PMID: 11809750 DOI: 10.1074/jbc.m109546200] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Low density lipoprotein (LDL) oxidation and monocyte infiltration of the vessel wall underlie atherogenesis. These cells express cyclooxygenase-2, but the way oxidized LDL stimulates cyclooxygenase-2 transcription is unknown. Oxidized LDL, oxidatively fragmented phospholipids isolated from oxidized LDL, a synthetic oxidized alkylphospholipid (azPC) that is a potent peroxisome proliferator activated receptor (PPAR) gamma agonist, or the PPARgamma agonist rosiglitazone all induced cyclooxygenase-2 expression and enhanced prostaglandin E(2) (PGE(2)) secretion in primary human monocytes. The cyclooxygenase-2 inhibitor NS398 blocked PPARgamma-induced PGE(2) secretion. Phospholipase A(1) and A(2) digestion shows that oxidized alkylphospholipids, and not oxidized fatty acids, were the relevant agonists. The upstream PPAR-responsive element (PPRE) of cyclooxygenase-2 was required for induction of a luciferase reporter by oxidized phospholipids, azPC, and rosiglitazone, and a (COX-2 PPRE)(3)-luciferase reporter was responsive to these PPARgamma agonists. Circulating human monocytes do not contain PPARgamma, but PPARgamma was induced rapidly (<4 h) in monocytes upon ligation of surface ICAM-3, but not P-selectin glycoprotein-1 even though both interactions prime cytokine secretion. Cyclooxygenase-2 induction by oxidized phospholipids only occurred in monocytes containing PPARgamma. Thus PPARgamma was induced rapidly in primary monocytes by appropriate outside-in signaling, sensitizing them to previously undetectable agonists in oxidized LDL. Cyclooxygenase-2 and PGE(2) secretion are induced, not inhibited, by selective PPARgamma agonists that include oxidatively fragmented phospholipids in oxidized LDL.
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Affiliation(s)
- Aaron V Pontsler
- Department of Pathology, University of Utah, Salt Lake City, UT 84112, USA
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Affiliation(s)
- Linda L. Demer
- From the Departments of Medicine and Physiology, UCLA School of Medicine, Los Angeles, Calif
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Clay CE, Atsumi GI, High KP, Chilton FH. Early de novo gene expression is required for 15-deoxy-Delta 12,14-prostaglandin J2-induced apoptosis in breast cancer cells. J Biol Chem 2001; 276:47131-5. [PMID: 11668172 DOI: 10.1074/jbc.c100339200] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Cyclopentenone prostaglandin derivatives of arachidonic acid are potent inducers of apoptosis in a variety of cancer cell types. Several investigators have shown that the terminal derivative of prostaglandin J(2) (PGJ(2)) metabolism, 15-deoxy-Delta(12,14)-PGJ(2) (15dPGJ(2)), induces apoptosis in breast cancer cells and is a potent activator of the nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARgamma), but 15dPGJ(2) effects can be mediated by PPARgamma-dependent and PPARgamma-independent mechanisms. Here we report that 15dPGJ(2) regulates early gene expression critical to apoptosis. Specifically, 15dPGJ(2) induces potent and irreversible S phase arrest that is correlated with expression of genes critical to cell cycle arrest and apoptosis, including the cyclin-dependent kinase inhibitor p21(Waf1/Cip1) (p21). Inhibition of RNA or protein synthesis abrogates apoptosis induced by 15dPGJ(2) in breast cancer cells but potentiates apoptosis induced by tumor necrosis factor-alpha or CD95/Fas ligand. Additionally, 15dPGJ(2) induces caspase activation that is blocked by peptide caspase inhibitors. These data show that de novo gene transcription is necessary for 15dPGJ(2)-induced apoptosis in breast cancer cells. Critical candidate genes are likely to be revealed through analysis of differential cDNA array expression.
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Affiliation(s)
- C E Clay
- Department of Internal Medicine, Wake Forest University Baptist Medical Center, Winston Salem, NC 27157, USA
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