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Huang R, Yamamoto T, Nakata E, Ozaki T, Kurozumi K, Wei F, Tomizawa K, Fujimura A. CDKAL1 Drives the Maintenance of Cancer Stem-Like Cells by Assembling the eIF4F Translation Initiation Complex. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206542. [PMID: 36786012 PMCID: PMC10131790 DOI: 10.1002/advs.202206542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/06/2023] [Indexed: 06/18/2023]
Abstract
Cancer stem-like cells (CSCs) have a unique translation mode, but little is understood about the process of elongation, especially the contribution of tRNA modifications to the maintenance of CSCs properties. Here, it is reported that, contrary to the initial aim, a tRNA-modifying methylthiotransferase CDKAL1 promotes CSC-factor SALL2 synthesis by assembling the eIF4F translation initiation complex. CDKAL1 expression is upregulated in patients with worse prognoses and is essential for maintaining CSCs in rhabdomyosarcoma (RMS) and common cancers. Translatome analysis reveals that a group of mRNAs whose translation is CDKAL1-dependent contains cytosine-rich sequences in the 5' untranslated region (5'UTR). Mechanistically, CDKAL1 promotes the translation of such mRNAs by organizing the eIF4F translation initiation complex. This complex formation does not require the enzyme activity of CDKAL1 but requires only the NH2 -terminus domain of CDKAL1. Furthermore, sites in CDKAL1 essential for forming the eIF4F complex are identified and discovered candidate inhibitors of CDKAL1-dependent translation.
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Affiliation(s)
- Rongsheng Huang
- Department of Cellular PhysiologyOkayama University Graduate School of Medicine, Dentistry, and Pharmaceutical SciencesOkayamaOkayama700‐8558Japan
| | - Takahiro Yamamoto
- Department of Molecular PhysiologyKumamoto University Faculty of Life SciencesKumamotoKumamoto860‐0811Japan
| | - Eiji Nakata
- Department of Orthopedic SurgeryOkayama University Graduate School of Medicine, Dentistry, and Pharmaceutical SciencesOkayamaOkayama700‐8558Japan
| | - Toshifumi Ozaki
- Department of Orthopedic SurgeryOkayama University Graduate School of Medicine, Dentistry, and Pharmaceutical SciencesOkayamaOkayama700‐8558Japan
| | - Kazuhiko Kurozumi
- Department of NeurosurgeryHamamatsu University School of MedicineHamamatsuShizuoka431‐3192Japan
| | - Fanyan Wei
- Department of Modomics Biology and MedicineInstitute of Development, Aging and CancerTohoku UniversitySendaiMiyagi980‐8575Japan
| | - Kazuhito Tomizawa
- Department of Molecular PhysiologyKumamoto University Faculty of Life SciencesKumamotoKumamoto860‐0811Japan
| | - Atsushi Fujimura
- Department of Cellular PhysiologyOkayama University Graduate School of Medicine, Dentistry, and Pharmaceutical SciencesOkayamaOkayama700‐8558Japan
- Neutron Therapy Research CenterOkayama UniversityOkayamaOkayama700‐8558Japan
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2
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The Characterization and Differential Analysis of m 6A Methylation in Hycole Rabbit Muscle and Adipose Tissue and Prediction of Regulatory Mechanism about Intramuscular Fat. Animals (Basel) 2023; 13:ani13030446. [PMID: 36766336 PMCID: PMC9913852 DOI: 10.3390/ani13030446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 01/24/2023] [Accepted: 01/25/2023] [Indexed: 01/31/2023] Open
Abstract
N6-methyladenosine (m6A) widely participates in various life processes of animals, including disease, memory, growth and development, etc. However, there is no report on m6A regulating intramuscular fat deposition in rabbits. In this study, m6A modification of Hycole rabbit muscle and adipose tissues were detected by MeRIP-Seq. In this case, 3 methylases and 12 genes modified by m6A were found to be significantly different between muscle and adipose tissues. At the same time, we found 3 methylases can regulate the expression of 12 genes in different ways and the function of 12 genes is related to fat deposition base on existing studies. 12 genes were modified by m6A methylase in rabbit muscle and adipose tissues. These results suggest that 3 methylases may regulate the expression of 12 genes through different pathways. In addition, the analysis of results showed that 6 of the 12 genes regulated eight signaling pathways, which regulated intramuscular fat deposition. RT-qPCR was used to validate the sequencing results and found the expression results of RT-qPCR and sequencing results are consistent. In summary, METTL4, ZC3H13 and IGF2BP2 regulated intramuscular fat by m6A modified gene/signaling pathways. Our work provided a new molecular basis and a new way to produce rabbit meat with good taste.
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Exosome biopotentiated hydrogel restores damaged skeletal muscle in a porcine model of stress urinary incontinence. NPJ Regen Med 2022; 7:58. [PMID: 36175423 PMCID: PMC9523025 DOI: 10.1038/s41536-022-00240-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/05/2022] [Indexed: 11/28/2022] Open
Abstract
Urinary incontinence afflicts up to 40% of adult women in the United States. Stress urinary incontinence (SUI) accounts for approximately one-third of these cases, precipitating ~200,000 surgical procedures annually. Continence is maintained through the interplay of sub-urethral support and urethral sphincter coaptation, particularly during activities that increase intra-abdominal pressure. Currently, surgical correction of SUI focuses on the re-establishment of sub-urethral support. However, mesh-based repairs are associated with foreign body reactions and poor localized tissue healing, which leads to mesh exposure, prompting the pursuit of technologies that restore external urethral sphincter function and limit surgical risk. The present work utilizes a human platelet-derived CD41a and CD9 expressing extracellular vesicle product (PEP) enriched for NF-κB and PD-L1 and derived to ensure the preservation of lipid bilayer for enhanced stability and compatibility with hydrogel-based sustained delivery approaches. In vitro, the application of PEP to skeletal muscle satellite cells in vitro drove proliferation and differentiation in an NF-κB-dependent fashion, with full inhibition of impact on exposure to resveratrol. PEP biopotentiation of collagen-1 and fibrin glue hydrogel achieved sustained exosome release at 37 °C, creating an ultrastructural “bead on a string” pattern on scanning electron microscopy. Initial testing in a rodent model of latissimus dorsi injury documented activation of skeletal muscle proliferation of healing. In a porcine model of stress urinary incontinence, delivery of PEP-biopotentiated collagen-1 induced functional restoration of the external urethral sphincter. The histological evaluation found that sustained PEP release was associated with new skeletal muscle formation and polarization of local macrophages towards the regenerative M2 phenotype. The results provided herein serve as the first description of PEP-based biopotentiation of hydrogels implemented to restore skeletal muscle function and may serve as a promising approach for the nonsurgical management of SUI.
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Shirakawa T, Toyono T, Inoue A, Matsubara T, Kawamoto T, Kokabu S. Factors Regulating or Regulated by Myogenic Regulatory Factors in Skeletal Muscle Stem Cells. Cells 2022; 11:cells11091493. [PMID: 35563799 PMCID: PMC9104119 DOI: 10.3390/cells11091493] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 11/23/2022] Open
Abstract
MyoD, Myf5, myogenin, and MRF4 (also known as Myf6 or herculin) are myogenic regulatory factors (MRFs). MRFs are regarded as master transcription factors that are upregulated during myogenesis and influence stem cells to differentiate into myogenic lineage cells. In this review, we summarize MRFs, their regulatory factors, such as TLE3, NF-κB, and MRF target genes, including non-myogenic genes such as taste receptors. Understanding the function of MRFs and the physiology or pathology of satellite cells will contribute to the development of cell therapy and drug discovery for muscle-related diseases.
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Affiliation(s)
- Tomohiko Shirakawa
- Division of Orofacial Functions and Orthodontics, Department of Health Improvement, Kyushu Dental University, Kitakyushu 803-8580, Japan; (T.S.); (A.I.); (T.K.)
- Division of Molecular Signaling and Biochemistry, Department of Health Improvement, Kyushu Dental University, Kitakyushu 803-8580, Japan;
| | - Takashi Toyono
- Division of Anatomy, Department of Health Promotion, Kyushu Dental University, Kitakyushu 803-8580, Japan;
| | - Asako Inoue
- Division of Orofacial Functions and Orthodontics, Department of Health Improvement, Kyushu Dental University, Kitakyushu 803-8580, Japan; (T.S.); (A.I.); (T.K.)
- Division of Molecular Signaling and Biochemistry, Department of Health Improvement, Kyushu Dental University, Kitakyushu 803-8580, Japan;
| | - Takuma Matsubara
- Division of Molecular Signaling and Biochemistry, Department of Health Improvement, Kyushu Dental University, Kitakyushu 803-8580, Japan;
| | - Tatsuo Kawamoto
- Division of Orofacial Functions and Orthodontics, Department of Health Improvement, Kyushu Dental University, Kitakyushu 803-8580, Japan; (T.S.); (A.I.); (T.K.)
| | - Shoichiro Kokabu
- Division of Molecular Signaling and Biochemistry, Department of Health Improvement, Kyushu Dental University, Kitakyushu 803-8580, Japan;
- Correspondence: ; Tel.: +81-93-582-1131; Fax: +81-93-285-6000
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Jiang WD, Zhang L, Feng L, Wu P, Liu Y, Kuang SY, Li SW, Tang L, Mi HF, Zhang L, Zhou XQ. New Insight on the Immune Modulation and Physical Barrier Protection Caused by Vitamin A in Fish Gills Infected With Flavobacterium columnare. Front Immunol 2022; 13:833455. [PMID: 35401542 PMCID: PMC8992971 DOI: 10.3389/fimmu.2022.833455] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 02/23/2022] [Indexed: 11/13/2022] Open
Abstract
In this study, we have investigated the influence of vitamin A on gill barrier function of grass carp (Ctenopharyngodon idella) infected with Flavobacterium columnare. The fish were fed different concentrations of vitamin A diets for 10 weeks and then infected with F. columnare by immersion. We observed that optimal vitamin A significantly prevented gill rot morbidity in fish infected with F. columnare. Further investigations revealed that vitamin A boosted the gill immunity by increasing the contents of complements (C3 and C4), activities of acid phosphatase (ACP) and lysozyme, mRNAs of β-defensin-1, liver-expressed antimicrobial peptide 2A and 2B (LEAP-2A and LEAP-2B), hepcidin, and anti-inflammatory cytokines like transforming growth factor β1 (TGF-β1), TGF-β2, interleukin-10 (IL-10), and IL-11. It also enhanced the levels of various related signaling molecules including inhibitor protein κBα (IκBα), target of rapamycin (TOR), and ribosome protein S6 kinase 1 (S6K1) but downregulated the expression of pro-inflammatory cytokines including IL-1β, IL-8, tumor necrosis factor α (TNF-α), and interferon γ2 (IFN-γ2) and related signaling molecules including nuclear factor κB p65 (NF-κB p65) (rather than NF-κB p52), IκB kinase β (IKKβ), IKKγ (rather than IKKα), eIF4E-binding protein 1 (4E-BP1), and 4E-BP2 mRNA levels in fish gills. In addition, dietary vitamin A markedly lowered the concentrations of reactive oxygen species (ROS), malondialdehyde (MDA), and protein carbonyl (PC), increased both the activities and mRNAs of copper/zinc superoxide dismutase (Cu/ZnSOD), MnSOD, glutathione transferases (GSTs), glutathione peroxidase (GPx), and glutathione reductase (GR) associated with upregulation of NF-E2-related factor 2 (Nrf2) mRNAs and downregulation of Kelch-like-ECH-associated protein (Keap1a) and Keap1b mRNAs. Moreover, vitamin A decreased the mRNAs of different apoptotic mediators [caspases 8, 9, 3 (rather than 7)] associated with downregulation of signaling molecule p38 mitogen-activated protein kinase (p38MAPK) mRNAs in fish gills. Besides, vitamin A promoted tight junction (TJ) complex mRNAs [including claudin-b, -c, -3, -7, -12, occludin, and zonula occludens-1 (ZO-1)] that have been linked to the downregulation of myosin light chain kinase (MLCK) signaling. Taken together, the current study demonstrated for the first time that vitamin A markedly enhanced gill health associated with immune modulation and physical barrier protection. Based on protecting fish against gill rot morbidity, ACP activity, and against lipid peroxidation, optimum vitamin A concentrations in on-growing grass carp (262-997 g) were found to be 1,991, 2,188, and 2,934 IU/kg diet, respectively.
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Affiliation(s)
- Wei-Dan Jiang
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, China
| | - Li Zhang
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China
| | - Lin Feng
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, China
| | - Pei Wu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, China
| | - Yang Liu
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, China
| | - Sheng-Yao Kuang
- Animal Nutrition Institute, Sichuan Academy of Animal Science, Sichuan Animtech Feed Co. Ltd., Chengdu, China
| | - Shu-Wei Li
- Animal Nutrition Institute, Sichuan Academy of Animal Science, Sichuan Animtech Feed Co. Ltd., Chengdu, China
| | - Ling Tang
- Animal Nutrition Institute, Sichuan Academy of Animal Science, Sichuan Animtech Feed Co. Ltd., Chengdu, China
| | - Hai-Feng Mi
- Tongwei Co., Ltd., Healthy Aquaculture Key Laboratory of Sichuan Province, Chengdu, China
| | - Lu Zhang
- Tongwei Co., Ltd., Healthy Aquaculture Key Laboratory of Sichuan Province, Chengdu, China
| | - Xiao-Qiu Zhou
- Animal Nutrition Institute, Sichuan Agricultural University, Chengdu, China.,Fish Nutrition and Safety Production University Key Laboratory of Sichuan Province, Sichuan Agricultural University, Chengdu, China.,Key Laboratory of Animal Disease-Resistance Nutrition, Ministry of Education, Ministry of Agriculture and Rural Affairs, Key Laboratory of Sichuan Province, Sichuan, China
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6
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Wnt Activation and Reduced Cell-Cell Contact Synergistically Induce Massive Expansion of Functional Human iPSC-Derived Cardiomyocytes. Cell Stem Cell 2021; 27:50-63.e5. [PMID: 32619518 DOI: 10.1016/j.stem.2020.06.001] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 04/17/2020] [Accepted: 06/01/2020] [Indexed: 12/20/2022]
Abstract
Modulating signaling pathways including Wnt and Hippo can induce cardiomyocyte proliferation in vivo. Applying these signaling modulators to human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in vitro can expand CMs modestly (<5-fold). Here, we demonstrate massive expansion of hiPSC-CMs in vitro (i.e., 100- to 250-fold) by glycogen synthase kinase-3β (GSK-3β) inhibition using CHIR99021 and concurrent removal of cell-cell contact. We show that GSK-3β inhibition suppresses CM maturation, while contact removal prevents CMs from cell cycle exit. Remarkably, contact removal enabled 10 to 25 times greater expansion beyond GSK-3β inhibition alone. Mechanistically, persistent CM proliferation required both LEF/TCF activity and AKT phosphorylation but was independent from yes-associated protein (YAP) signaling. Engineered heart tissues from expanded hiPSC-CMs showed comparable contractility to those from unexpanded hiPSC-CMs, demonstrating uncompromised cellular functionality after expansion. In summary, we uncovered a molecular interplay that enables massive hiPSC-CM expansion for large-scale drug screening and tissue engineering applications.
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Zhang H, Guo Q, Liang Z, Wang M, Wang B, Sun-Waterhouse D, Waterhouse GI, Wang J, Ma C, Kang W. Anti-inflammatory and antioxidant effects of Chaetoglobosin Vb in LPS-induced RAW264.7 cells: Achieved via the MAPK and NF-κB signaling pathways. Food Chem Toxicol 2021; 147:111915. [DOI: 10.1016/j.fct.2020.111915] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 11/08/2020] [Accepted: 12/03/2020] [Indexed: 01/21/2023]
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8
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Di R, Yang Z, Xu P, Xu Y. Silencing PDK1 limits hypoxia-induced pulmonary arterial hypertension in mice via the Akt/p70S6K signaling pathway. Exp Ther Med 2019; 18:699-704. [PMID: 31281449 DOI: 10.3892/etm.2019.7627] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 06/15/2018] [Indexed: 12/16/2022] Open
Abstract
The present study aimed to investigate the effect of phosphoinositide-dependent protein kinase-1 (PDK1) on hypoxia-induced pulmonary arterial hypertension (PAH). A mouse model of hypoxia-induced PAH was generated using normal or PDK1-knockout mice. Histological analysis and hemodynamic evaluations were performed to identify the progression of PAH. The expression and phosphorylation of PDK1/protein kinase B (Akt) signaling pathway associated proteins were detected by western blot analysis. Increased lung vessel thickness, right ventricular (RV) systolic pressure (RVSP), RV hypertrophy index (RVHI) values [the RV weight-to-left ventricular (LV) plus septum (S) weight ratio] and PDK1 expression were observed in the hypoxia-induced PAH model compared with the normal control. The phosphorylation of AktT308, proline-rich Akt1 substrate 1 (PRAS40) and S6KT229 was also notably increased in the PAH model compared with the control. The changes of proteins were not observed in the hypoxia treated PDK1flox/+ : Tie2-Cre mice. Similarly, the RVSP and RVHI values, and PDK1 expression were reduced in the hypoxia treated PDK1flox/+: Tie2-Cre mice to a level comparable with those in the control, suggesting that PDK1 partial knockout significantly limited hypoxia-induced PAH. The results of the present study indicate that PDK1 is essential for hypoxia-induced PAH through the PDK1/Akt/S6K signaling cascades.
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Affiliation(s)
- Ruomin Di
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai 200240, P.R. China
| | - Zhongzhou Yang
- MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Nanjing University, Nanjing, Jiangsu 210061, P.R. China
| | - Peng Xu
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai 200240, P.R. China
| | - Yingjia Xu
- Department of Cardiology, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai 200240, P.R. China
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Chen SJ, Yue J, Zhang JX, Jiang M, Hu TQ, Leng WD, Xiang L, Li XY, Zhang L, Zheng F, Yuan Y, Guo LY, Pan YM, Yan YW, Wang JN, Chen SY, Tang JM. Continuous exposure of isoprenaline inhibits myoblast differentiation and fusion through PKA/ERK1/2-FOXO1 signaling pathway. Stem Cell Res Ther 2019; 10:70. [PMID: 30819239 PMCID: PMC6394105 DOI: 10.1186/s13287-019-1160-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 01/25/2019] [Accepted: 01/30/2019] [Indexed: 01/08/2023] Open
Abstract
Aim The objective of this study is to determine if exuberant sympathetic nerve activity is involved in muscle satellite cell differentiation and myoblast fusion. Methods and results By using immunoassaying and western blot analyses, we found that β1 and β2-adrenergic receptors (AdR) were expressed in C2C12 cells. The differentiated satellite cells exhibited an increased expression of β2-AdR, as compared with the proliferating cells. Continuous exposure of isoprenaline (ISO), a β-AdR agonist, delayed C2C12 cell differentiation, and myoblast fusion in time- and dose-dependent manner. ISO also increased short myotube numbers while decreasing long myotube numbers, consistent with the greater reduction in MyHC1, MyHC2a, and MyHC2x expression. Moreover, continuous exposure of ISO gradually decreased the ratio of PKA RI/RII, and PKA RI activator efficiently reversed the ISO effect on C2C12 cell differentiation and myoblast fusion while PKA inhibitor H-89 deteriorated the effects. Continuous single-dose ISO increased β1-AdR expression in C2C12 cells. More importantly, the cells showed enhanced phospho-ERK1/2 levels, resulting in increasing phospho-β2-AdR levels while decreasing β2-AdR levels, and the specific effects could be abolished by ERK1/2 inhibitor. Furthermore, continuous exposure of ISO induced FOXO1 nuclear translocation and increased the levels of FOXO1 in nuclear extracts while reducing pAKT, p-p38MAPK, and pFOXO1 levels. Conversely, blockade of ERK1/2 signaling partially abrogated ISO effects on AKT, p38MAPK, and FOXO1signaling, which partially restored C2C12 cell differentiation and myoblast fusion, leading to an increase in the numbers of medium myotube along with the increased expression of MyHC1 and MyHC2a. Conclusion Continuous exposure of ISO impedes satellite cell differentiation and myoblast fusion, at least in part, through PKA-ERK1/2-FOXO1 signaling pathways, which were associated with the reduced β2-AdR and increased β1-AdR levels. Electronic supplementary material The online version of this article (10.1186/s13287-019-1160-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shao-Juan Chen
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China.,Department of Stomatology, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Jing Yue
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Jing-Xuan Zhang
- Department of Physiology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China.,Institute of biomedicine and Key Lab of Human Embryonic Stem Cell of Hubei Province, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Miao Jiang
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Tu-Qiang Hu
- Department of Stomatology, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Wei-Dong Leng
- Department of Stomatology, Taihe Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Li Xiang
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China.,Department of Physiology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Xin-Yuan Li
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Lei Zhang
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China.,Institute of biomedicine and Key Lab of Human Embryonic Stem Cell of Hubei Province, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Fei Zheng
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Ye Yuan
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Lin-Yun Guo
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China.,Institute of biomedicine and Key Lab of Human Embryonic Stem Cell of Hubei Province, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Ya-Mu Pan
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Yu-Wen Yan
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Jia-Ning Wang
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China.,Institute of biomedicine and Key Lab of Human Embryonic Stem Cell of Hubei Province, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China
| | - Shi-You Chen
- Department of Physiology & Pharmacology, The University of Georgia, Athens, GA30602, USA
| | - Jun-Ming Tang
- Department of Cardiology, and Institute of Clinical Medicine, Renmin Hospital, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China. .,Department of Physiology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China. .,Institute of biomedicine and Key Lab of Human Embryonic Stem Cell of Hubei Province, Hubei University of Medicine, Shiyan, 442000, Hubei, People's Republic of China.
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10
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Shi J, Shan S, Li H, Song G, Li Z. Anti-inflammatory effects of millet bran derived-bound polyphenols in LPS-induced HT-29 cell via ROS/miR-149/Akt/NF-κB signaling pathway. Oncotarget 2017; 8:74582-74594. [PMID: 29088809 PMCID: PMC5650364 DOI: 10.18632/oncotarget.20216] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 06/05/2017] [Indexed: 12/24/2022] Open
Abstract
The pro-inflammatory and anti-inflammatory maladjustment has been acknowledged as one of the chief causations of inflammatory diseases and even cancers. Previous studies showed that plant-derived polyphenolic compounds were the most potent anti-oxidant and anti-inflammatory agents among all natural compounds. The present study indicates that bound polyphenols of inner shell (BPIS) from foxtail millet bran can display anti-inflammatory effects in LPS-induced HT-29 cells and in nude mice. Mechanistically, BPIS restrained the level of various pro-inflammatory cytokines (IL-1β, IL-6, IL-8), and enhanced the expression level of anti-inflammatory cytokine (IL-10) by blocking the nuclear factor-kappaB (NF-κB)-p65 nuclear translocation. Further, we found the elevated miR-149 expression by BPIS-induced ROS accumulation, directly targeted the Akt expression to block NF-κB nuclear translocation. Taken together, these novel findings provide new insights into the development of BPIS as an anti-inflammatory agent via the signaling cascade of ROS/miR-149/Akt/NF-κB axis.
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Affiliation(s)
- Jiangying Shi
- Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of National Ministry of Education, Shanxi University, Taiyuan 030006, PR China
| | - Shuhua Shan
- Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of National Ministry of Education, Shanxi University, Taiyuan 030006, PR China
| | - Hanqing Li
- Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of National Ministry of Education, Shanxi University, Taiyuan 030006, PR China.,College of Life Science, Shanxi University, Taiyuan 030006, China
| | - Guisheng Song
- Department of Medicine, Division of Gastroenterology, University of Minnesota Medical School, Minneapolis, Minnesota, MN 55455, USA
| | - Zhuoyu Li
- Institute of Biotechnology, Key Laboratory of Chemical Biology and Molecular Engineering of National Ministry of Education, Shanxi University, Taiyuan 030006, PR China.,College of Life Science, Shanxi University, Taiyuan 030006, China
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Nie X, Tang J, Liu Y, Cai R, Miao Q, Zhao Y, Chen C. Fullerenol inhibits the cross-talk between bone marrow-derived mesenchymal stem cells and tumor cells by regulating MAPK signaling. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2017; 13:1879-1890. [PMID: 28365417 DOI: 10.1016/j.nano.2017.03.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 03/07/2017] [Accepted: 03/21/2017] [Indexed: 01/10/2023]
Abstract
The interaction between bone marrow-derived mesenchymal stem cells (BDMSCs) and tumor cells promotes tumor proliferation and metastasis. We found that 4T1 breast cancer cells induced malignant differentiation of BDMSCs and that BDMSCs also affected the growth and metastasis of 4T1 cells. However, when the interaction between BDMSCs and 4T1 cells was attenuated or blocked by C60(OH)22 nanoparticles, tumor growth and metastasis were significantly suppressed. The suppression of metastasis depended on the activation of MAPK signals in the BDMSCs, whereas the underlying pathways were related to a broad range of extracellular responses and were modulated by the secretion of multiple cytokines. Interestingly, C60(OH)22 regulated the malignantly differentiated BDMSCs via the Erk- and p38-MAPK and its downstream NF-κB signal pathway, but in normal BDMSCs regulation occurred only through Erk- and p38-MAPK and not by NF-κB activation. This study may provide a novel mechanism for C60(OH)22 nanoparticles as an anti-tumor drug.
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Affiliation(s)
- Xin Nie
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, University of Chinese Academy of Sciences, Beijing, China
| | - Jinglong Tang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, University of Chinese Academy of Sciences, Beijing, China
| | - Ying Liu
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, University of Chinese Academy of Sciences, Beijing, China
| | - Rong Cai
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, University of Chinese Academy of Sciences, Beijing, China
| | - Qing Miao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, University of Chinese Academy of Sciences, Beijing, China; Divisions of Pediatric Surgery and Pediatric Pathology, Departments of Surgery and Pathology, Children's Research Institute, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Yuliang Zhao
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, University of Chinese Academy of Sciences, Beijing, China
| | - Chunying Chen
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety & CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, University of Chinese Academy of Sciences, Beijing, China.
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12
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Gao H, Lin L, Haq IU, Zeng SM. Inhibition of NF-κB promotes autophagy via JNK signaling pathway in porcine granulosa cells. Biochem Biophys Res Commun 2016; 473:311-316. [PMID: 27016483 DOI: 10.1016/j.bbrc.2016.03.101] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 03/21/2016] [Indexed: 12/15/2022]
Abstract
The transcription factor nuclear factor-κB (NF-κB) plays an important role in diverse processes, including cell proliferation and differentiation, apoptosis and inflammation. However, the role of NF-κB in porcine follicle development is not clearly elucidated. In this study, we demonstrated that follicle stimulating hormone (FSH) increased the level of inhibitor of NF-κB (IκB) protein and promoted the cytoplasmic localization of p65, indicating that FSH inhibits the activation of NF-κB in porcine granulosa cells. Moreover, inhibition of NF-κB by FSH or another specific inhibitor of NF-κB, pyrrolidine dithiocarbamate (PDTC), could activate JNK signaling and enhance autophagic activity in porcine granulosa cells. Knockdown of RelA (p65) Subunit of NF-κB by RNA interference abrogated the activation of JNK signaling pathway and the increase of autophagic protein expression by FSH. Meanwhile, the functional significance of FSH or PDTC-mediated autophagy were further investigated. Our results demonstrated that the increased autophagy promoted progesterone secretion in porcine granulosa cells. Blockage of autophagy by chloroquine obviated the FSH or PDTC-induced progesterone production. Taken together, these results indicate that inhibition of NF-κB increased autophagy via JNK signaling, and promote steroidogenesis in porcine granulosa cells. Our results provide new insights into the regulation and function of autophagy in mammalian follicle development.
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Affiliation(s)
- Hui Gao
- Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Lu Lin
- Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Ihtesham Ul Haq
- Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China
| | - Shen-Ming Zeng
- Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing 100193, China.
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13
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Garcia-Guerra L, Vila-Bedmar R, Carrasco-Rando M, Cruces-Sande M, Martín M, Ruiz-Gómez A, Ruiz-Gómez M, Lorenzo M, Fernández-Veledo S, Mayor F, Murga C, Nieto-Vázquez I. Skeletal muscle myogenesis is regulated by G protein-coupled receptor kinase 2. J Mol Cell Biol 2014; 6:299-311. [PMID: 24927997 DOI: 10.1093/jmcb/mju025] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
G protein-coupled receptor kinase 2 (GRK2) is an important serine/threonine-kinase regulating different membrane receptors and intracellular proteins. Attenuation of Drosophila Gprk2 in embryos or adult flies induced a defective differentiation of somatic muscles, loss of fibers, and a flightless phenotype. In vertebrates, GRK2 hemizygous mice contained less but more hypertrophied skeletal muscle fibers than wild-type littermates. In C2C12 myoblasts, overexpression of a GRK2 kinase-deficient mutant (K220R) caused precocious differentiation of cells into immature myotubes, which were wider in size and contained more fused nuclei, while GRK2 overexpression blunted differentiation. Moreover, p38MAPK and Akt pathways were activated at an earlier stage and to a greater extent in K220R-expressing cells or upon kinase downregulation, while the activation of both kinases was impaired in GRK2-overexpressing cells. The impaired differentiation and fewer fusion events promoted by enhanced GRK2 levels were recapitulated by a p38MAPK mutant, which was able to mimic the inhibitory phosphorylation of p38MAPK by GRK2, whereas the blunted differentiation observed in GRK2-expressing clones was rescued in the presence of a constitutively active upstream stimulator of the p38MAPK pathway. These results suggest that balanced GRK2 function is necessary for a timely and complete myogenic process.
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Affiliation(s)
- Lucia Garcia-Guerra
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Complutense University, 28040 Madrid, Spain CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Barcelona, Spain Instituto de Investigaciones Biomédicas Alberto Sols (CSIC-UAM), 28029 Madrid, Spain CIBER de enfermedades neurodegenerativas (CIBERNED), 28049 Madrid, Spain
| | - Rocío Vila-Bedmar
- Departament of Molecular Biology and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain Instituto de Investigación Sanitaria la Princesa, 28006 Madrid, Spain
| | | | - Marta Cruces-Sande
- Departament of Molecular Biology and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain Instituto de Investigación Sanitaria la Princesa, 28006 Madrid, Spain
| | - Mercedes Martín
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC), 28049 Madrid, Spain
| | - Ana Ruiz-Gómez
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC), 28049 Madrid, Spain
| | - Mar Ruiz-Gómez
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC), 28049 Madrid, Spain
| | - Margarita Lorenzo
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Complutense University, 28040 Madrid, Spain CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Barcelona, Spain
| | - Sonia Fernández-Veledo
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Barcelona, Spain Hospital Universitari de Tarragona Joan XXIII. IISPV. Universitat Rovira i Virgili, 43007 Tarragona, Spain
| | - Federico Mayor
- Departament of Molecular Biology and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain Instituto de Investigación Sanitaria la Princesa, 28006 Madrid, Spain
| | - Cristina Murga
- Departament of Molecular Biology and Centro de Biología Molecular Severo Ochoa (CSIC-UAM), 28049 Madrid, Spain Instituto de Investigación Sanitaria la Princesa, 28006 Madrid, Spain
| | - Iria Nieto-Vázquez
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, Complutense University, 28040 Madrid, Spain CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08017 Barcelona, Spain
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14
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HuR and miR-1192 regulate myogenesis by modulating the translation of HMGB1 mRNA. Nat Commun 2014; 4:2388. [PMID: 24005720 PMCID: PMC4005793 DOI: 10.1038/ncomms3388] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 08/02/2013] [Indexed: 12/14/2022] Open
Abstract
Upon muscle injury, the high mobility group box 1 (HMGB1) protein is upregulated and secreted to initiate reparative responses. Here we show that HMGB1 controls myogenesis both in vitro and in vivo during development and after adult muscle injury. HMGB1 expression in muscle cells is regulated at the translational level: the miRNA miR-1192 inhibits HMGB1 translation and the RNA-binding protein HuR promotes it. HuR binds to a cis-element, HuR binding sites (HuRBS), located in the 3'UTR of the HMGB1 transcript, and at the same time miR-1192 is recruited to an adjacent seed element. The binding of HuR to the HuRBS prevents the recruitment of Argonaute 2 (Ago2), overriding miR-1192-mediated translation inhibition. Depleting HuR reduces myoblast fusion and silencing miR-1192 re-establishes the fusion potential of HuR-depleted cells. We propose that HuR promotes the commitment of myoblasts to myogenesis by enhancing the translation of HMGB1 and suppressing the translation inhibition mediated by miR-1192.
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15
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Maull EA, Ahsan H, Edwards J, Longnecker MP, Navas-Acien A, Pi J, Silbergeld EK, Styblo M, Tseng CH, Thayer KA, Loomis D. Evaluation of the association between arsenic and diabetes: a National Toxicology Program workshop review. ENVIRONMENTAL HEALTH PERSPECTIVES 2012; 120:1658-70. [PMID: 22889723 PMCID: PMC3548281 DOI: 10.1289/ehp.1104579] [Citation(s) in RCA: 261] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 08/10/2012] [Indexed: 05/17/2023]
Abstract
BACKGROUND Diabetes affects an estimated 346 million persons globally, and total deaths from diabetes are projected to increase > 50% in the next decade. Understanding the role of environmental chemicals in the development or progression of diabetes is an emerging issue in environmental health. In 2011, the National Toxicology Program (NTP) organized a workshop to assess the literature for evidence of associations between certain chemicals, including inorganic arsenic, and diabetes and/or obesity to help develop a focused research agenda. This review is derived from discussions at that workshop. OBJECTIVES Our objectives were to assess the consistency, strength/weaknesses, and biological plausibility of findings in the scientific literature regarding arsenic and diabetes and to identify data gaps and areas for future evaluation or research. The extent of the existing literature was insufficient to consider obesity as an outcome. DATA SOURCES, EXTRACTION, AND SYNTHESIS Studies related to arsenic and diabetes or obesity were identified through PubMed and supplemented with relevant studies identified by reviewing the reference lists in the primary literature or review articles. CONCLUSIONS Existing human data provide limited to sufficient support for an association between arsenic and diabetes in populations with relatively high exposure levels (≥ 150 µg arsenic/L in drinking water). The evidence is insufficient to conclude that arsenic is associated with diabetes in lower exposure (< 150 µg arsenic/L drinking water), although recent studies with better measures of outcome and exposure support an association. The animal literature as a whole was inconclusive; however, studies using better measures of diabetes-relevant end points support a link between arsenic and diabetes.
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Affiliation(s)
- Elizabeth A Maull
- Biomolecular Screening Branch, Division of the National Toxicology Program, National Institute of Environmental Sciences (NIEHS), National Institutes of Health (NIH), Department of Health and Human Services (DHHS), Research Triangle Park, North Carolina, USA
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16
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Ge Y, Chen J. Mammalian target of rapamycin (mTOR) signaling network in skeletal myogenesis. J Biol Chem 2012; 287:43928-35. [PMID: 23115234 DOI: 10.1074/jbc.r112.406942] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mammalian (or mechanistic) target of rapamycin (mTOR) regulates a wide range of cellular and developmental processes by coordinating signaling responses to mitogens, nutrients, and various stresses. Over the last decade, mTOR has emerged as a master regulator of skeletal myogenesis, controlling multiple stages of the myofiber formation process. In this minireview, we present an emerging view of the signaling network underlying mTOR regulation of myogenesis, which contrasts with the well established mechanisms in the regulation of cell and muscle growth. Current questions for future studies are also highlighted.
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Affiliation(s)
- Yejing Ge
- Department of Cell and Developmental Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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17
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Buitrago CG, Arango NS, Boland RL. 1α,25(OH)2D3-dependent modulation of Akt in proliferating and differentiating C2C12 skeletal muscle cells. J Cell Biochem 2012; 113:1170-81. [PMID: 22095470 DOI: 10.1002/jcb.23444] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
We previously reported that 1α,25-dihydroxy-vitamin D(3) [1α,25(OH)(2)D(3)] induces non-transcriptional rapid responses through activation of Src and MAPKs in the skeletal muscle cell line C2C12. In the present study we investigated the modulation of Akt by the secosteroid hormone in C2C12 cells at proliferative stage (myoblasts) and at early differentiation stage. In proliferating cells, 1α,25(OH)(2)D(3) activates Akt by phosphorylation in Ser473 in a time-dependent manner (5-60 min). When these cells were pretreated with methyl-beta-cyclodextrin to disrupt caveolae microdomains, hormone-induced activation of Akt was suppressed. Similar results were obtained by siRNA silencing of caveolin-1 expression, further indicating that hormone effects on cell membrane caveolae are required for downstream signaling. PI3K and p38 MAPK, but not ERK1/2, participate in 1α,25(OH)(2)D(3) activation of Akt in myoblasts. The involvement of p38 MAPK in Akt phosphorylation by the hormone probably occurs through MAPK-activated protein kinase 2 (MK2), which is activated by the steroid. In addition, the participation of Src in Akt phosphorylation by 1α,25(OH)(2)D(3) was demonstrated using the inhibitor PP2 and antisense oligodeoxynucleotides that suppress Src expression. We also observed that PI3K participates in hormone-induced proliferation. During the early phase of C2C12 cell differentiation 1α,25(OH)(2)D(3) also increases Akt phosphorylation and activates Src. Of relevance, Src and PI3K are involved in Akt activation and in MHC and myogenin increased expression by 1α,25(OH)(2)D(3). Altogether, these data suggest that 1α,25(OH)(2)D(3) upregulates Akt through Src, PI(3)K, and p38 MAPK to stimulate myogenesis in C2C12 cells.
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Affiliation(s)
- Claudia G Buitrago
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina
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18
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Berger F, Büchsler I, Munz B. The effect of the NF-kappa B inhibitors curcumin and lactacystin on myogenic differentiation of rhabdomyosarcoma cells. Differentiation 2012; 83:271-81. [PMID: 22469857 DOI: 10.1016/j.diff.2012.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Revised: 01/23/2012] [Accepted: 02/01/2012] [Indexed: 11/17/2022]
Abstract
Rhabdomyosarcoma is a soft tissue sarcoma mainly seen in children. Despite considerable progress within the last few years, therapeutic approaches for this type of tumor are still limited. The respective tumor cells originate from myogenic precursor cells and are characterized by a blockade in their differentiation program. Interestingly, there is a direct inverse correlation between the differentiation status of a specific rhabdomyosarcoma cell and its metastatic potential. Thus, here, we tested whether the ubiquitous transcription factor NF-κB, which regulates myogenic differentiation and is also a promising therapeutic target in the treatment of other types of tumors, might be an interesting candidate for the development of novel rhabdomyosarcoma treatment strategies. For this purpose, we analyzed NF-κB activity (classical pathway) in myoblasts with different differentiation potential, specifically in three different rhabdomyosarcoma cell lines. In addition, we inhibited NF-κB activity in these cells and analyzed the effects on myogenic differentiation. We show that after the induction of differentiation, NF-κB activity declines rapidly in normal myoblasts, but only slightly in rhabdomyosarcoma cells. However, after treatment of the cells with two different small-molecule NF-κB-inhibiting compounds, the IKK inhibitor curcumin and the proteasome inhibitor lactacystin, we found that neither curcumin nor lactacystin promoted myogenic differentiation in either normal myoblasts or rhabdomyosarcoma cells. Taken together, our data suggest that treatment with curcumin or lactacystin might not be a suitable approach in the treatment of rhabdomyosarcoma.
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Affiliation(s)
- Felicitas Berger
- Charité, Institute of Physiology, University Medicine Berlin, Thielallee 71, D-14195 Berlin, Germany
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19
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Hakuno F, Yamauchi Y, Kaneko G, Yoneyama Y, Nakae J, Chida K, Kadowaki T, Yamanouchi K, Nishihara M, Takahashi SI. Constitutive expression of insulin receptor substrate (IRS)-1 inhibits myogenic differentiation through nuclear exclusion of Foxo1 in L6 myoblasts. PLoS One 2011; 6:e25655. [PMID: 21991327 PMCID: PMC3185002 DOI: 10.1371/journal.pone.0025655] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Accepted: 09/09/2011] [Indexed: 11/19/2022] Open
Abstract
Insulin-like growth factors (IGFs) are well known to play essential roles in enhancement of myogenic differentiation. In this report we showed that initial IGF-I signal activation but long-term IGF-1 signal termination are required for myogenic differentiation. L6 myoblast stably transfected with myc-epitope tagged insulin receptor substrate-1, myc-IRS-1 (L6-mIRS1) was unable to differentiate into myotubes, indicating that IRS-1 constitutive expression inhibited myogenesis. To elucidate the molecular mechanisms underlying myogenic inhibition, IGF-I signaling was examined. IGF-I treatment of control L6 cells for 18 h resulted in a marked suppression of IGF-I stimulated IRS-1 association with the p85 PI 3-kinase and suppression of activation of Akt that correlated with a down regulation of IRS-1 protein. L6-mIRS1 cells, in contrast, had sustained high levels of IRS-1 protein following 18 h of IGF-I treatment with persistent p85 PI 3-kinase association with IRS-1, Akt phosphorylation and phosphorylation of the downstream Akt substrate, Foxo1. Consistent with Foxo1 phosphorylation, Foxo1 protein was excluded from the nuclei in L6-mIRS1 cells, whereas Foxo1 was localized in the nuclei in control L6 cells during induction of differentiation. In addition, L6 cells stably expressing a dominant-interfering form of Foxo1, Δ256Foxo1 (L6-Δ256Foxo1) were unable to differentiate into myotubes. Together, these data demonstrate that IGF-I regulation of Foxo1 nuclear localization is essential for the myogenic program in L6 cells but that persistent activation of IGF-1 signaling pathways results in a negative feedback to prevent myogenesis.
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Affiliation(s)
- Fumihiko Hakuno
- Department of Animal Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yoko Yamauchi
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, Japan
| | - Gen Kaneko
- Department of Animal Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yosuke Yoneyama
- Department of Animal Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Jun Nakae
- Frontier Medicine on Metabolic Syndrome, Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan
| | - Kazuhiro Chida
- Department of Animal Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tatsuhiko Kadowaki
- Department of Bioengineering Sciences, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, Japan
| | - Keitaro Yamanouchi
- Department of Veterinary Medical Science, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Masugi Nishihara
- Department of Veterinary Medical Science, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Shin-Ichiro Takahashi
- Department of Animal Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail:
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Xiang X, Zhao J, Xu G, Li Y, Zhang W. mTOR and the differentiation of mesenchymal stem cells. Acta Biochim Biophys Sin (Shanghai) 2011; 43:501-10. [PMID: 21642276 DOI: 10.1093/abbs/gmr041] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The mammalian target of rapamycin (mTOR), an evolutionarily conserved serine-threonine protein kinase, belongs to the phosphoinositide 3-kinase (PI3K)-related kinase family, which contains a lipid kinase-like domain within their C-terminal region. Recent studies have revealed that mTOR as a critical intracellular molecule can sense the extracellular energy status and regulate the cell growth and proliferation in a variety of cells and tissues. This review summarizes our current understanding about the effects of mTOR on cell differentiation and tissue development, with an emphasis on the lineage determination of mesenchymal stem cells. mTOR can promote adipogenesis in white adipocytes, brown adipocytes, and muscle satellite cells, while rapamycin inhibits the adipogenic function of mTOR. mTOR signaling may function to affect osteoblast proliferation and differentiation, however, rapamycin has been reported to either inhibit or promote osteogenesis. Although the precise mechanism remains unclear, mTOR is indispensable for myogenesis. Depending on the cell type, rapamycin has been reported to inhibit, promote, or have no effect on myogenesis.
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Affiliation(s)
- Xinxin Xiang
- Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Department of Physiology and Pathophysiology, Health Science Center, Peking University, Beijing, China
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21
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Proto-oncogenic H-Ras, K-Ras, and N-Ras are involved in muscle differentiation via phosphatidylinositol 3-kinase. Cell Res 2010; 20:919-34. [DOI: 10.1038/cr.2010.92] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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22
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Bakkar N, Guttridge DC. NF-kappaB signaling: a tale of two pathways in skeletal myogenesis. Physiol Rev 2010; 90:495-511. [PMID: 20393192 DOI: 10.1152/physrev.00040.2009] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
NF-kappaB is a ubiquitiously expressed transcription factor that plays vital roles in innate immunity and other processes involving cellular survival, proliferation, and differentiation. Activation of NF-kappaB is controlled by an IkappaB kinase (IKK) complex that can direct either canonical (classical) NF-kappaB signaling by degrading the IkappaB inhibitor and releasing p65/p50 dimers to the nucleus, or causes p100 processing and nuclear translocation of RelB/p52 via a noncanonical (alternative) pathway. Under physiological conditions, NF-kappaB activity is transiently regulated, whereas constitutive activation of this transcription factor typically in the classical pathway is associated with a multitude of disease conditions, including those related to skeletal muscle. How NF-kappaB functions in muscle diseases is currently under intense investigation. Insight into this role of NF-kappaB may be gained by understanding at a more basic level how this transcription factor contributes to skeletal muscle cell differentiation. Recent data from knockout mice support that the classical NF-kappaB pathway functions as an inhibitor of skeletal myogenesis and muscle regeneration acting through multiple mechanisms. In contrast, alternative NF-kappaB signaling does not appear to be required for myofiber conversion, but instead functions in myotube homeostasis by regulating mitochondrial biogenesis. Additional knowledge of these signaling pathways in skeletal myogenesis should aid in the development of specific inhibitors that may be useful in treatments of muscle disorders.
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Affiliation(s)
- Nadine Bakkar
- Department of Molecular Virology, Immunology, and Medical Genetics, Arthur G. James Comprehensive Cancer Center, The Ohio State University, Columbus, Ohio 43210, USA
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23
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Hypoxia converts the myogenic action of insulin-like growth factors into mitogenic action by differentially regulating multiple signaling pathways. Proc Natl Acad Sci U S A 2010; 107:5857-62. [PMID: 20231451 DOI: 10.1073/pnas.0909570107] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Insulin-like growth factors (IGFs) stimulate myoblast proliferation and differentiation. It remains elusive how these mutually exclusive cellular responses are elicited by the same growth factor. Here we report that whereas IGF promotes myoblast differentiation under normoxia, it stimulates proliferation under hypoxia. Hypoxia activates the HIF-1 transcriptional program and knockdown of HIF-1alpha changes the mitogenic action of IGF into myogenic action under hypoxia. Conversely, overexpression of HIF-1alpha abolishes the myogenic effect of IGF under normoxia. Under normoxia, IGF activates the Akt-mTOR, p38, and Erk1/2 MAPK pathways. Hypoxia suppresses basal and IGF-induced Akt-mTOR and p38 activity, whereas it enhances and prolongs IGF-induced Erk1/2 activation in a HIF-1-dependent fashion. Activation of Akt-mTOR and p38 promotes myogenesis, and p38 also inhibits proliferation. Activation of Erk stimulates myoblast proliferation but inhibits differentiation. These results suggest that hypoxia converts the myogenic action of IGFs into mitogenic action by differentially regulating multiple signaling pathways via HIF-1-dependent mechanisms. Our findings provide a mechanistic explanation for the paradoxical actions of IGFs during myogenesis and reveal a novel mechanism by which cells sense and integrate growth factor signals and oxygen availability in their microenvironments.
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Overlapping functions of nuclear envelope proteins NET25 (Lem2) and emerin in regulation of extracellular signal-regulated kinase signaling in myoblast differentiation. Mol Cell Biol 2009; 29:5718-28. [PMID: 19720741 DOI: 10.1128/mcb.00270-09] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Mutations in certain nuclear envelope (NE) proteins cause muscular dystrophies and other disorders, but the disease mechanisms remain unclear. The nuclear envelope transmembrane protein NET25 (Lem2) is a truncated paralog of MAN1, an NE component linked to bone disorders. NET25 and MAN1 share an approximately 40-residue LEM homology domain with emerin, the protein mutated in X-linked Emery-Dreifuss muscular dystrophy. However, roles for NET25 and MAN1 in myogenesis have not yet been described. Using RNA interference in C2C12 myoblasts, we show for the first time that both NET25 and MAN1 are required for myogenic differentiation. NET25 depletion causes hyperactivation of extracellular signal-regulated kinase 1/2 at the onset of differentiation, and pharmacological inhibition of this transient overactivation rescues myogenesis. In contrast, pharmacological inhibition of both mitogen-activated protein kinase and transforming growth factor beta signaling is required to rescue differentiation after MAN1 depletion. Ectopic expression of silencing-resistant NET25 rescues myogenesis after depletion of emerin but not after MAN1 silencing. Thus, NET25 and emerin have at least partially overlapping functions during myogenic differentiation, which are distinct from those of MAN1. Our work supports the hypothesis that deregulation of cell signaling contributes to NE-linked disorders and suggests that mutations in NET25 and MAN1 may cause muscle diseases.
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Abstract
Forkhead proteins, and FoxO1 in particular, play a significant role in regulating whole body energy metabolism. Glucose homeostasis is achieved by adjusting endogenous glucose production as well as glucose uptake by peripheral tissues in response to insulin. In the fasted state, the liver is primarily responsible for maintaining glucose levels, with FoxO1 playing a key role in promoting the expression of gluconeogenic enzymes. Following feeding, pancreatic beta cells secrete insulin, which promotes the uptake of glucose by peripheral tissues including skeletal muscle and adipose tissue, and can in part suppress gluconeogenic enzyme expression in the liver. In addition to directly regulating metabolism, FoxO1 also plays a role in the formation of both adipose tissue and skeletal muscle, two major organs that are critical for maintaining energy homeostasis. The importance of FoxO1 in energy homeostasis is particularly striking under conditions of metabolic dysfunction or insulin resistance. In obese or diabetic states, FoxO1-dependent gene expression promotes some of the deleterious characteristics associated with these conditions, including hyperglycemia and glucose intolerance. In addition, the increase in pancreatic beta cell mass that normally occurs in response to a rise in insulin demand is blunted by nuclear FoxO1 expression. However, under these same pathophysiological conditions, FoxO1 expression may help drive the expression of genes involved in combating oxidative stress, thereby preserving cellular function. FoxO1 may also be involved in promoting the switch from carbohydrate to fatty acid as the major energy source during starvation.
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Bakkar N, Wang J, Ladner KJ, Wang H, Dahlman JM, Carathers M, Acharyya S, Rudnicki MA, Hollenbach AD, Guttridge DC. IKK/NF-kappaB regulates skeletal myogenesis via a signaling switch to inhibit differentiation and promote mitochondrial biogenesis. ACTA ACUST UNITED AC 2008; 180:787-802. [PMID: 18299349 PMCID: PMC2265568 DOI: 10.1083/jcb.200707179] [Citation(s) in RCA: 176] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Nuclear factor κB (NF-κB) is involved in multiple skeletal muscle disorders, but how it functions in differentiation remains elusive given that both anti- and promyogenic activities have been described. In this study, we resolve this by showing that myogenesis is controlled by opposing NF-κB signaling pathways. We find that myogenesis is enhanced in MyoD-expressing fibroblasts deficient in classical pathway components RelA/p65, inhibitor of κB kinase β (IKKβ), or IKKγ. Similar increases occur in myoblasts lacking RelA/p65 or IKKβ, and muscles from RelA/p65 or IKKβ mutant mice also contain higher fiber numbers. Moreover, we show that during differentiation, classical NF-κB signaling decreases, whereas the induction of alternative members IKKα, RelB, and p52 occurs late in myogenesis. Myotube formation does not require alternative signaling, but it is important for myotube maintenance in response to metabolic stress. Furthermore, overexpression or knockdown of IKKα regulates mitochondrial content and function, suggesting that alternative signaling stimulates mitochondrial biogenesis. Together, these data reveal a unique IKK/NF-κB signaling switch that functions to both inhibit differentiation and promote myotube homeostasis.
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Affiliation(s)
- Nadine Bakkar
- Human Cancer Genetics Program, Department of Molecular Virology, Immunology, and Medical Genetics, The Ohio State University, Columbus, OH 43210, USA
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Nedachi T, Kadotani A, Ariga M, Katagiri H, Kanzaki M. Ambient glucose levels qualify the potency of insulin myogenic actions by regulating SIRT1 and FoxO3a in C2C12 myocytes. Am J Physiol Endocrinol Metab 2008; 294:E668-78. [PMID: 18230695 DOI: 10.1152/ajpendo.00640.2007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nutrition availability is one of the major environmental signals influencing cell fate, such as proliferation, differentiation, and apoptosis, often functioning in concert with other humoral factors, including insulin. Herein, we show that low-serum-induced differentiation of C(2)C(12) myocytes is significantly hampered under low glucose (LG; 5 mM) compared with high glucose (HG; 22.5 mM) conditions, concurrently with nuclear accumulation of SIRT1, an NAD(+)-dependent deacetylase, and FoxO3a, both of which are implicated in the negative regulation of myogenesis. Intriguingly, insulin appears to exert opposite actions, depending on glucose availability, with regard to the regulation of SIRT1 and FoxO3a abundance, which apparently contributes to modulating the potency of insulin's myogenic action. Namely, insulin exerts a potent myogenic effect in the presence of sufficient glucose, whereas insulin is unable to exert its myogenic action under LG conditions, since insulin evokes massive upregulation of both SIRT1 and FoxO3a in the absence of sufficient ambient glucose. In addition, the hampered differentiation state under LG is significantly restored by sirtinol, a SIRT1 inhibitor, whereas insulin abolished this sirtinol-dependent restoration, indicating that insulin can function as a negative as well as a positive myogenic factor depending on glucose availability. Taken together, our data reveal the importance of ambient glucose levels in the regulation of myogenesis and also in the determination of insulin's myogenic potency, which is achieved, at least in part, through regulation of the cellular contents and localization of SIRT1 and FoxO3a in differentiating C(2)C(12) myocytes.
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Affiliation(s)
- Taku Nedachi
- Division of Biomaterials, Tohoku University Biomedical Engineering Research Organization, Tohoku University, Sendai, Japan
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De Alvaro C, Nieto-Vazquez I, Rojas JM, Lorenzo M. Nuclear exclusion of forkhead box O and Elk1 and activation of nuclear factor-kappaB are required for C2C12-RasV12C40 myoblast differentiation. Endocrinology 2008; 149:793-801. [PMID: 17962350 DOI: 10.1210/en.2007-0657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Activating ras point mutations are frequently found in skeletal muscle tumors such as rhabdomyosarcomas. In this study we investigated the impact of two different H-ras mutants in skeletal muscle differentiation: RasV12, a constitutively active form, and RasV12C40, a mutant deficient in Raf1 activation. Stably transfected C2C12-RasV12 myoblasts actively proliferated as indicated by the sustained expression of proliferating cell nuclear antigen and retinoblastoma at the hyperphosphorylated state and failed to express differentiation markers. This differentiation-defective phenotype was a consequence of the chronic p44/p42MAPK phosphorylation and the inability of the cells to activate AKT. Moreover, we observed that p44/p42MAPK activation in C2C12-RasV12 myoblasts phosphorylated the ETS-like transcription factor (ELK) 1, which translocates to the nuclei and seemed to be involved in maintaining myoblast proliferation. C2C12-RasV12C40 myoblasts cultured in low serum repressed phosphorylation of p44/p42MAPK and ELK1, resulting in cell cycle arrest and myogenic differentiation. Under this condition, activation of AKT, p70S6K, and p38MAPK was produced, leading to formation of myotubes in 3 d, 1 d earlier than in control C2C12-AU5 cells. Moreover, the expression of muscle-specific proteins, mainly the terminal differentiation markers caveolin-3 and myosin heavy chain, also occurred 1 d earlier than in control cells. Furthermore, AKT activation produced phosphorylation of Forkhead box O that led to nuclear exclusion and inactivation, allowing myogenesis. In addition, we found an induction of nuclear factor-kappaB activity in the nucleus in C2C12-RasV12C40 myotubes attributed to p38MAPK activation. Accordingly, muscle differentiation is associated with a pattern of transcription factors that involves nuclear exclusion ELK1 and Forkhead box O and the increase in nuclear factor-kappaB DNA binding.
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Affiliation(s)
- Cristina De Alvaro
- Departamento de Bioquimica y Biologia Molecular II, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain.
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Lorenzo M, Fernández-Veledo S, Vila-Bedmar R, Garcia-Guerra L, De Alvaro C, Nieto-Vazquez I. Insulin resistance induced by tumor necrosis factor-alpha in myocytes and brown adipocytes. J Anim Sci 2007; 86:E94-104. [PMID: 17940160 DOI: 10.2527/jas.2007-0462] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Insulin resistance is an important contributor to the pathogenesis of type 2 diabetes, and obesity is a risk factor for its development, in part because adipose tissue secretes proteins, called adipokines, that may influence insulin sensitivity. Among these molecules, tumor necrosis factor (TNF)-alpha has been proposed as a link between obesity and insulin resistance because TNF-alpha is overexpressed in adipose tissues of obese animals and humans, and obese mice lacking either TNF-alpha or its receptor show protection against developing insulin resistance. Direct exposure to TNF-alpha induces a state of insulin resistance in terms of glucose uptake in myocytes and brown adipocytes because of the activation of proinflammatory pathways that impair insulin signaling at the level of the insulin receptor substrate (IRS) proteins. In this regard, the Ser(307) residue in IRS-1 has been identified as a site for the inhibitory effects of TNF-alpha in myotubes, with p38 mitogen-activated protein kinase and inhibitor kB kinase being involved in the phosphorylation of this residue. Conversely, Ser phosphorylation of IRS-2 mediated by TNF-alpha activation of mitogen-activated protein kinase was the mechanism found in brown adipocytes. Protein-Tyr phosphatase (PTP)1B acts as a physiological, negative regulator of insulin signaling by dephosphorylating the phosphotyrosine residues of the insulin receptor and IRS-1, and PTP1B expression is increased in muscle and white adipose tissue of obese and diabetic humans and rodents. Moreover, up-regulation of PTP1B expression was recently found in cells treated with TNF-alpha Accordingly, myocytes and primary brown adipocytes deficient in PTP1B are protected against insulin resistance induced by this cytokine. Furthermore, down-regulation of PTP1B activity is possible by the use of pharmacological agonists of nuclear receptors that restore insulin sensitivity in the presence of TNF-alpha. In conclusion, the lack of PTP1B in muscle and brown adipocytes increases insulin sensitivity and glucose uptake and could confer protection against insulin resistance induced by adipokines.
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Affiliation(s)
- M Lorenzo
- Departamento de Bioquimica y Biologia Molecular II, Facultad de Farmacia, Universidad Complutense, 28040-Madrid, Spain.
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Lim MJ, Seo YH, Choi KJ, Cho CH, Kim BS, Kim YH, Lee J, Lee H, Jung CY, Ha J, Kang I, Kim SS. Suppression of c-Src activity stimulates muscle differentiation via p38 MAPK activation. Arch Biochem Biophys 2007; 465:197-208. [PMID: 17612500 DOI: 10.1016/j.abb.2007.06.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2007] [Revised: 05/25/2007] [Accepted: 06/03/2007] [Indexed: 11/28/2022]
Abstract
Role of c-Src in muscle differentiation has been controversial. Here, we investigated if c-Src positively or negatively regulates muscle differentiation, using H9c2 and C2C12 cell lines. Inhibition of c-Src by treatment with PP1 and SU6656, pharmacologic inhibitors of Src family kinases, or by expression of a dominant negative c-Src, all induced muscle differentiation in proliferation medium (PM). In differentiating cells in differentiation medium (DM), c-Src activity gradually decreased and reached basal level 3 days after induction of differentiation. Inhibition of c-Src suppressed Raf/MEK/ERK pathway but activated p38 MAPK. Inhibition of p38 MAPK did not affect c-Src activity in PM. However, it reactivated Raf/MEK/ERK pathway in c-Src-inhibited cells regardless of PM or DM. Concomitant inhibition of c-Src and p38 MAPK activities blocked muscle differentiation in both media. In conclusion, suppression of c-Src activity stimulates muscle differentiation by activating p38 MAPK uni-directionally.
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Affiliation(s)
- Min Jin Lim
- Department of Biochemistry and Molecular Biology (BK21 project), Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea
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31
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Wang H, Hertlein E, Bakkar N, Sun H, Acharyya S, Wang J, Carathers M, Davuluri R, Guttridge DC. NF-kappaB regulation of YY1 inhibits skeletal myogenesis through transcriptional silencing of myofibrillar genes. Mol Cell Biol 2007; 27:4374-87. [PMID: 17438126 PMCID: PMC1900043 DOI: 10.1128/mcb.02020-06] [Citation(s) in RCA: 193] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 12/11/2006] [Accepted: 03/20/2007] [Indexed: 11/20/2022] Open
Abstract
NF-kappaB signaling is implicated as an important regulator of skeletal muscle homeostasis, but the mechanisms by which this transcription factor contributes to muscle maturation and turnover remain unclear. To gain insight into these mechanisms, gene expression profiling was examined in C2C12 myoblasts devoid of NF-kappaB activity. Interestingly, even in proliferating myoblasts, the absence of NF-kappaB caused the pronounced induction of several myofibrillar genes, suggesting that NF-kappaB functions as a negative regulator of late-stage muscle differentiation. Although several myofibrillar promoters contain predicted NF-kappaB binding sites, functional analysis using the troponin-I2 gene as a model revealed that NF-kappaB-mediated repression does not occur through direct DNA binding. In the search for an indirect mediator, the transcriptional repressor YinYang1 (YY1) was identified. While inducers of NF-kappaB stimulated YY1 expression in multiple cell types, genetic ablation of the RelA/p65 subunit of NF-kappaB in both cultured cells and adult skeletal muscle correlated with reduced YY1 transcripts and protein. NF-kappaB regulation of YY1 occurred at the transcriptional level, mediated by direct binding of the p50/p65 heterodimer complex to the YY1 promoter. Furthermore, YY1 was found associated with multiple myofibrillar promoters in C2C12 myoblasts containing NF-kappaB activity. Based on these results, we propose that NF-kappaB regulation of YY1 and transcriptional silencing of myofibrillar genes represent a new mechanism by which NF-kappaB functions in myoblasts to modulate skeletal muscle differentiation.
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Affiliation(s)
- Huating Wang
- Human Cancer Genetics Program, The Ohio State University College of Medicine, Columbus, OH 43210, USA
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32
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Keren A, Tamir Y, Bengal E. The p38 MAPK signaling pathway: a major regulator of skeletal muscle development. Mol Cell Endocrinol 2006; 252:224-30. [PMID: 16644098 DOI: 10.1016/j.mce.2006.03.017] [Citation(s) in RCA: 259] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Skeletal muscle development is regulated by extracellular growth factors that transmit largely unknown signals into the cell affecting the muscle-transcription program. One intracellular signaling pathway activated during the differentiation of myogenic cell lines is p38 mitogen-activated protein kinase (MAPK). As a result of modifying the activity of p38 in myoblasts, the pathway proved essential for the expression of muscle-specific genes. P38 affects the activities of transcription factors from the MyoD and MEF2 families and participates in the remodeling of chromatin at specific muscle-regulatory regions. P38 cooperates with the myogenic transcription factors in the activation of a subset of late-transcribed genes, hence contributing to the temporal expression of genes during differentiation. Recent developmental studies with mouse and Xenopus embryos, substantiated and further extended the essential role of p38 in myogenesis. Evidence exists supporting the crucial role for p38 signaling in activating MEF2 transcription factors during somite development in mice. In Xenopus, p38 signaling was shown to be needed for the early expression of Myf5 and for the expression of several muscle structural genes. The emerging data indicate that p38 participates in several stages of the myogenic program.
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Affiliation(s)
- Aviad Keren
- Department of Biochemistry, Rappaport Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology, P.O. Box 9649, Haifa 31096, Israel
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Rodríguez-Escudero I, Roelants F, Thorner J, Nombela C, Molina M, Cid V. Reconstitution of the mammalian PI3K/PTEN/Akt pathway in yeast. Biochem J 2006; 390:613-23. [PMID: 15913452 PMCID: PMC1198941 DOI: 10.1042/bj20050574] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The mammalian signalling pathway involving class I PI3K (phosphoinositide 3-kinase), PTEN (phosphatidylinositol 3-phosphatase) and PKB (protein kinase B)/c-Akt has roles in multiple processes, including cell proliferation and apoptosis. To facilitate novel approaches for genetic, molecular and pharmacological analyses of these proteins, we have reconstituted this signalling pathway by heterologous expression in the unicellular eukaryote, Saccharomyces cerevisiae (yeast). High-level expression of the p110 catalytic subunit of mammalian PI3K dramatically inhibits yeast cell growth. This effect depends on PI3K kinase activity and is reversed partially by a PI3K inhibitor (LY294002) and reversed fully by co-expression of catalytically active PTEN (but not its purported yeast orthologue, Tep1). Growth arrest by PI3K correlates with loss of PIP2 (phosphatidylinositol 4,5-bisphosphate) and its conversion into PIP3 (phosphatidylinositol 3,4,5-trisphosphate). PIP2 depletion causes severe rearrangements of actin and septin architecture, defects in secretion and endocytosis, and activation of the mitogen-activated protein kinase, Slt2. In yeast producing PIP3, PKB/c-Akt localizes to the plasma membrane and its phosphorylation is enhanced. Phospho-specific antibodies show that both active and kinase-dead PKB/c-Akt are phosphorylated at Thr308 and Ser473. Thr308 phosphorylation, but not Ser473 phosphorylation, requires the yeast orthologues of mammalian PDK1 (3-phosphoinositide-dependent protein kinase-1): Pkh1 and Pkh2. Elimination of yeast Tor1 and Tor2 function, or of the related kinases (Tel1, Mec1 and Tra1), did not block Ser473 phosphorylation, implicating another kinase(s). Reconstruction of the PI3K/PTEN/Akt pathway in yeast permits incisive study of these enzymes and analysis of their functional interactions in a simplified context, establishes a new tool to screen for novel agonists and antagonists and provides a method to deplete PIP2 uniquely in the yeast cell.
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Affiliation(s)
- Isabel Rodríguez-Escudero
- *Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Pza. de Ramón y Cajal s/n, 28040 Madrid, Spain
| | - Françoise M. Roelants
- †Department of Molecular and Cell Biology, Division of Biochemistry and Molecular Biology, University of California, Berkeley, CA 94720, U.S.A
| | - Jeremy Thorner
- †Department of Molecular and Cell Biology, Division of Biochemistry and Molecular Biology, University of California, Berkeley, CA 94720, U.S.A
| | - César Nombela
- *Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Pza. de Ramón y Cajal s/n, 28040 Madrid, Spain
| | - María Molina
- *Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Pza. de Ramón y Cajal s/n, 28040 Madrid, Spain
- To whom correspondence should be addressed (email )
| | - Víctor J. Cid
- *Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Pza. de Ramón y Cajal s/n, 28040 Madrid, Spain
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Dayer JM, Molnarfi N, Burger D. From cellular receptors to transduction–transcription pathways for cytokines: at which level should the inhibition be targeted in inflammation? Expert Opin Biol Ther 2005; 5 Suppl 1:S83-96. [PMID: 16187943 DOI: 10.1517/14712598.5.1.s83] [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: 12/16/2022]
Abstract
An imbalance in cytokine homeostasis is considered to play a major part in the pathogenesis of immuno-inflammatory diseases. Since the identification and cloning of cytokines and their receptors, therapeutic approaches have been developed with the purpose of impeding the interaction between the ligand (cytokine) and its specific receptor, or interactions that involve the use of anti-inflammatory cytokines to switch off inflammation. Although some diseases have been treated successfully with cytokines or anticytokines (i.e., anti-TNF, and to a lesser extent recombinant IL-1 receptor antagonist, in rheumatoid arthritis; IFN-beta in multiple sclerosis), the fact remains that these therapies do not abrogate the concomitant use of steroids or immunosuppressive drugs, and that a significant percentage of patients do not respond to such therapies; these are important limitations. The identification of signalling pathways preferentially used in inflammatory conditions has boosted approaches that target these intracellular mechanisms. This review examines the different therapeutic approaches that may be considered for the treatment of immuno-inflammatory diseases, and discusses the advantages and disadvantages of targeting extracellular or intracellular mechanisms.
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Affiliation(s)
- Jean-Michel Dayer
- University Hospital & Faculty of Medicine, 24, Rue Micheli-du-Crest, 1211 Geneva 14, Switzerland.
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35
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de Alvaro C, Martinez N, Rojas JM, Lorenzo M. Sprouty-2 overexpression in C2C12 cells confers myogenic differentiation properties in the presence of FGF2. Mol Biol Cell 2005; 16:4454-61. [PMID: 16000370 PMCID: PMC1196351 DOI: 10.1091/mbc.e05-05-0419] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Myoblast C2C12 cells cultured in the presence of FGF2 actively proliferate and showed a differentiation-defective phenotype compared with cells cultured in low serum or in the presence of insulin. These FGF2 effects are associated with sustained activation of p44/p42-MAPK and lack of activation of AKT. Here we demonstrate that Sprouty-2, a protein involved in the negative feedback of receptor tyrosine kinase signaling, when stably overexpressed in C2C12 cells and in the presence of FGF2 produces growth arrest (precluding the expression of PCNA and the phosphorylation of retinoblastoma and inducing the expression of p21(CIP)) and myogenesis (multinucleated myotubes formation, induction of creatine kinase and expression of myosin heavy chain protein). These events were accompanied by repression of p44/p42-MAPK and activation of AKT. When C2C12 cells were stably transfected with a Sprouty-2 (Y55F) mutant defective in inhibiting p44/p42-MAPK activation by FGF, myoblasts in the presence of FGF continue to grow and completely fail to form myotubes. This work is the first evidence of the contribution of sprouty genes to myogenic differentiation in the presence of FGF2.
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Affiliation(s)
- Cristina de Alvaro
- Departamento de Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain
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36
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Hsu SH, Hsieh-Li HM, Huang HY, Huang PH, Li H. bHLH-zip Transcription Factor Spz1 Mediates Mitogen-Activated Protein Kinase Cell Proliferation, Transformation, and Tumorigenesis. Cancer Res 2005; 65:4041-50. [PMID: 15899793 DOI: 10.1158/0008-5472.can-04-3658] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BHLH-zip proteins usually play important regulatory roles in cell growth and differentiation. In this study, we show that Spz1, a bHLH-zip transcription factor, acts downstream of mitogen-activated protein kinase (MAPK, extracellular signal-regulated kinase 1/2) to up-regulate cell proliferation and tumorigenesis. In addition, through an interaction with proliferating cell nuclear antigen (PCNA) promoter, Spz1 induced cell proliferation concomitant with an increase in PCNA gene expression. Spz1-transfected cells formed colony foci on soft agar and developed fibrosarcoma tumors in nude mice. MAPK directly interacted and phosphorylated Spz1 protein, which increased PCNA transcription and cell tumorigenic activities. Reduction of endogenous Spz1 expression via RNA interference decreased cell proliferation in p19 embryonic carcinoma cells. High levels of Spz1 expression were detected in murine tumor cell lines and tumor samples of both human and Spz1 transgenic mice. Thus, Spz1 may act as a proto-oncogene, participating in the MAPK signal pathway, and be a potential therapeutic target in the treatment of Ras-induced tumors.
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Im E, Akare S, Powell A, Martinez JD. Ursodeoxycholic Acid Can Suppress Deoxycholic Acid-Induced Apoptosis by Stimulating Akt/PKB-Dependent Survival Signaling. Nutr Cancer 2005; 51:110-6. [PMID: 15749637 DOI: 10.1207/s15327914nc5101_15] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
The nontoxic bile acid ursodeoxycholic acid (UDCA) is reported to be an anti-apoptotic agent with efficacy against a variety of death stimuli including the cytotoxic bile acid deoxycholic acid (DCA). To gain insight into this anti-apoptotic property, we tested UDCA for its ability to protect the colon carcinoma-derived cell line HCT116 against DCA-induced apoptosis. We found that UDCA could suppress DCA-induced apoptosis in a time- and dose-dependent manner and that this effect correlated with Akt phosphorylation. Importantly, UDCA lost its ability to protect cells from DCA-induced cell death when Akt activity was suppressed genetically using a dominant negative Akt mutant or when PI3K activity was inhibited pharmacologically. These results suggest that UDCA can protect HCT116 cells against DCA-induced apoptosis by stimulating Akt-dependent survival signaling.
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Affiliation(s)
- Eunok Im
- Arizona Cancer Center, Department of Cell Biology and Anatomy, University of Arizona, Tucson, Arizona 85724, USA
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Abstract
Cell replication is tightly controlled in normal tissues and aberrant during disease progression, such as in tumorigenesis. The replication of cells can be divided into four distinct phases: Gap 1 (G1), synthesis (S), gap 2 (G2), and mitosis (M). The progression from one phase to the next is intricately regulated and has many "checkpoints" that take into account cellular status and environmental cues. Among the modulators of cell cycle progression are specific nutrients, which function as energy sources or regulate the production and/or function of proteins needed to advance cells through a replicative cycle. In this review, we focus on the roles of specific nutrients (vitamin A, vitamin D, iron, folic acid, vitamin B12, zinc, and glucose) in the control of cell cycle progression and discuss how insights into the mechanisms by which these nutrients modulate this process can be and have been used to control aberrant cell growth in the treatment of prevalent pathologies.
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Affiliation(s)
- Brenda L Bohnsack
- Children's Nutrition Research Center, Baylor College of Medicine, One Baylor Plaza, Houston, Texas 77030, USA.
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Sasson IE, Stern MJ. FGF and PI3 kinase signaling pathways antagonistically modulate sex muscle differentiation in C. elegans. Development 2004; 131:5381-92. [PMID: 15469970 DOI: 10.1242/dev.01423] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Myogenesis in vertebrate myocytes is promoted by activation of the phosphatidyl-inositol 3'-kinase (PI3 kinase) pathway and inhibited by fibroblast growth factor (FGF) signaling. We show that hyperactivation of the Caenorhabditis elegans FGF receptor, EGL-15, similarly inhibits the differentiation of the hermaphrodite sex muscles. Activation of the PI3 kinase signaling pathway can partially suppress this differentiation defect, mimicking the antagonistic relationship between these two pathways known to influence vertebrate myogenesis. When ectopically expressed in body wall muscle precursor cells, hyperactivated EGL-15 can also interfere with the proper development of the body wall musculature. Hyperactivation of EGL-15 has also revealed additional effects on a number of fundamental processes within the postembryonic muscle lineage, such as cell division polarity. These studies provide important in vivo insights into the contribution of FGF signaling events to myogenesis.
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Affiliation(s)
- Isaac E Sasson
- Yale University School of Medicine, Department of Genetics, I-354 SHM, PO Box 208005, New Haven, CT 06520-8005, USA
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Sarker KP, Lee KY. L6 myoblast differentiation is modulated by Cdk5 via the PI3K–AKT–p70S6K signaling pathway. Oncogene 2004; 23:6064-70. [PMID: 15208659 DOI: 10.1038/sj.onc.1207819] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Cdk5 regulates myogenesis but the signaling cascade through which Cdk5 modulates this process remains to be characterized. Here, we investigated whether PI3K, Akt, p70S6K, p38 MAPK, p44/42 MAPK, and Egr-1 serve as upstream regulators of Cdk5 during L6 myoblast differentiation. Upon serum reduction, we found that besides elevated expression of Cdk5 and its activator, p35, and increased Cdk5/p35 activity, Egr-1, Akt, p70S6K, and p38 MAPK activity were upregulated in differentiating L6 cells. However, p44/42 MAPK was downregulated and SAPK/JNK was unaffected. LY294002, a PI3K inhibitor, blocked the activation of Akt and p70S6K, indicating that Akt and p70S6K activation is linked to PI3K activation. The lack of LY294002 effect on p38 MAPK suggests that p38 MAPK activation is not associated with PI3K activation. Rapamycin, a specific inhibitor of FRAP/mTOR (the upstream kinase of p70S6K), also blocked p70S6K activation, indicating the involvement of FRAP/mTOR activation. LY294002 and rapamycin also blocked the enhancement of Egr-1 level, Cdk5 activity, and myogenin expression, suggesting that upregulation of these factors is coupled to PI3K-p70S6K activation. Overexpression of dominant-negative-Akt also reduced Cdk5/p35 activity and myogenin expression, indicating that the PI3K-p70S6K-Egr-1-Cdk5 signaling cascade is linked to Akt activation. SB2023580, a p38 MAPK inhibitor, had no effect on p70S6K, Egr-1, or Cdk5 activity, suggesting that p38 MAPK activation lies in a pathway distinct from the PI3K-Akt-p70S6K-Egr-1 pathway that we identify as the upstream modulator of Cdk5 activity during L6 myoblast differentiation.
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Affiliation(s)
- Krishna P Sarker
- Department of Cell Biology and Anatomy, Cancer Biology and Neuroscience Research Groups, The University of Calgary, Calgary, Alberta, Canada T2N 4N1
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41
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Burchfield JG, Lennard AJ, Narasimhan S, Hughes WE, Wasinger VC, Corthals GL, Okuda T, Kondoh H, Biden TJ, Schmitz-Peiffer C. Akt Mediates Insulin-stimulated Phosphorylation of Ndrg2. J Biol Chem 2004; 279:18623-32. [PMID: 14985363 DOI: 10.1074/jbc.m401504200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The protein kinase Akt mediates several metabolic and mitogenic effects of insulin, whereas activation of protein kinase C (PKC) isoforms has been implicated in the inhibition of insulin action. We have previously shown that both PKC and PKCepsilon are activated in skeletal muscle of insulin-resistant high fat-fed rats, and to identify potential substrates for these kinases, we incubated recombinant PKC isoforms with rat muscle fractions in vitro. PKC specifically phosphorylated a 48-kDa protein that was subsequently identified by mass spectrometry as Ndrg2. Ndrg2 is highly related to N-Myc downstream-regulated protein 1, which has been linked to stress responses, cell proliferation, and differentiation, although Ndrg2 itself is not repressed by N-Myc. Ndrg2 contains several potential phosphorylation sites, including three Akt consensus sequences. Ndrg2 phosphorylation was enhanced in [32P]orthophosphate-labeled C2C12 muscle cells co-overexpressing either PKC or Akt. Phosphorylation of Ndrg2 was examined further using a phospho (Ser/Thr) Akt substrate antibody. Insulin increased Ndrg2 phosphorylation in C2C12 cells in a wortmannin- and palmitate-inhibitable manner, whereas rapamycin, PD98059, and bisindoylmaleimide I had no effect, supporting a direct role for Akt. Mutation of Ndrg2 indicated that Thr-348 is the major phosphorylation site detected by the antibody and that Akt stimulates phosphorylation of this site, whereas PKC phosphorylates Ser-332. PKC overexpression, however, diminished the effect of insulin on Thr-348 phosphorylation without reducing Akt activation, suggesting that this is mediated through phosphorylation of Ndrg2 at Ser-332. Our data identify Ndrg2 as a novel insulin-dependent phosphoprotein and suggest that PKC may inhibit insulin action in part by reducing its phosphorylation by Akt.
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Affiliation(s)
- James G Burchfield
- Cell Signalling Group, Diabetes and Obesity Program, Garvan Institute of Medical Research, Sydney, New South Wales, Australia
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42
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de Alvaro C, Teruel T, Hernandez R, Lorenzo M. Tumor necrosis factor alpha produces insulin resistance in skeletal muscle by activation of inhibitor kappaB kinase in a p38 MAPK-dependent manner. J Biol Chem 2004; 279:17070-8. [PMID: 14764603 DOI: 10.1074/jbc.m312021200] [Citation(s) in RCA: 292] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Insulin stimulation produced a reliable 3-fold increase in glucose uptake in primary neonatal rat myotubes, which was accompanied by a similar effect on GLUT4 translocation to plasma membrane. Tumor necrosis factor (TNF)-alpha caused insulin resistance on glucose uptake and GLUT4 translocation by impairing insulin stimulation of insulin receptor (IR) and IR substrate (IRS)-1 and IRS-2 tyrosine phosphorylation, IRS-associated phosphatidylinositol 3-kinase activation, and Akt phosphorylation. Because this cytokine produced sustained activation of stress and proinflammatory kinases, we have explored the hypothesis that insulin resistance by TNF-alpha could be mediated by these pathways. In this study we demonstrate that pretreatment with PD169316 or SB203580, inhibitors of p38 MAPK, restored insulin signaling and normalized insulin-induced glucose uptake in the presence of TNF-alpha. However, in the presence of PD98059 or SP600125, inhibitors of p42/p44 MAPK or JNK, respectively, insulin resistance by TNF-alpha was still produced. Moreover, TNF-alpha produced inhibitor kappaB kinase (IKK)-beta activation and inhibitor kappaB-beta and -alpha degradation in a p38 MAPK-dependent manner, and treatment with salicylate (an inhibitor of IKK) completely restored insulin signaling. Furthermore, TNF-alpha produced serine phosphorylation of IR and IRS-1 (total and on Ser(307) residue), and these effects were completely precluded by pretreatment with either PD169316 or salicylate. Consequently, TNF-alpha, through activation of p38 MAPK and IKK, produces serine phosphorylation of IR and IRS-1, impairing its tyrosine phosphorylation by insulin and the corresponding activation of phosphatidylinositol 3-kinase and Akt, leading to insulin resistance on glucose uptake and GLUT4 translocation.
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Affiliation(s)
- Cristina de Alvaro
- Departamento de Bioquimica y Biologia Molecular II, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain
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43
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Hirose Y, Katayama M, Stokoe D, Haas-Kogan DA, Berger MS, Pieper RO. The p38 mitogen-activated protein kinase pathway links the DNA mismatch repair system to the G2 checkpoint and to resistance to chemotherapeutic DNA-methylating agents. Mol Cell Biol 2003; 23:8306-15. [PMID: 14585987 PMCID: PMC262371 DOI: 10.1128/mcb.23.22.8306-8315.2003] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Although human cells exposed to DNA-methylating agents undergo mismatch repair (MMR)-dependent G(2) arrest, the basis for the linkage between MMR and the G(2) checkpoint is unclear. We noted that mitogen-activated protein kinase p38alpha was activated in MMR-proficient human glioma cells exposed to the chemotherapeutic methylating agent temozolomide (TMZ) but not in paired cells made MMR deficient by expression of a short inhibitory RNA (siRNA) targeted to the MMR protein Mlh1. Furthermore, activation of p38alpha in MMR-proficient cells was associated with nuclear inactivation of the cell cycle regulator Cdc25C phosphatase and its downstream target Cdc2 and with activation of the G(2) checkpoint, actions which were suppressed by the p38alpha/beta inhibitors SB203580 and SB202590 or by expression of a p38alpha siRNA. Finally, pharmacologic or genetic inhibition of p38alpha increased the sensitivity of MMR-proficient cells to the cytotoxic actions of TMZ by increasing the percentage of cells that underwent mitotic catastrophe as a consequence of G(2) checkpoint bypass. These results suggest that p38alpha links DNA MMR to the G(2) checkpoint and to resistance to chemotherapeutic DNA-methylating agents. The p38 pathway may therefore represent a new target for the development of agents to sensitize tumor cells to chemotherapeutic methylating agents.
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Affiliation(s)
- Yuichi Hirose
- UCSF Cancer Center, Department of Neurological Surgery, University of California-San Francisco, 2340 Sutter Street, San Francisco, CA 94115-0875, USA
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45
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Porras A, Zuluaga S, Valladares A, Alvarez AM, Herrera B, Fabregat I, Benito M. Long-term treatment with insulin induces apoptosis in brown adipocytes: role of oxidative stress. Endocrinology 2003; 144:5390-401. [PMID: 14500576 DOI: 10.1210/en.2003-0622] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Trying to define the precise role played by insulin regulating the survival of brown adipocytes, we have used rat fetal brown adipocytes maintained in primary culture. The effect of insulin on apoptosis and the mechanisms involved were assessed. Different from the known effects of insulin as a survival factor, we have found that long-term treatment (72 h) with insulin induces apoptosis in rat fetal brown adipocytes. This process is dependent on the phosphatidylinositol 3-kinase/mammalian target of rapamycin/p70 S6 kinase pathway. Short-term treatment with the conditioned medium from brown adipocytes treated with insulin for 72 h mimicked the apoptotic effect of insulin. During the process, caspase 8 activation, Bid cleavage, cytochrome c release, and activation of caspases 9 and 3 are sequentially produced. Treatment with the caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp (Z-VAD), prevents activation of this apoptotic cascade. The antioxidants, ascorbic acid and superoxide dismutase, also impair this process of apoptosis. Moreover, generation of reactive oxygen species (ROS), probably through reduced nicotinamide adenine dinucleotide phosphate oxidases, and a late decrease in reduced glutathione content are produced. According to this, antioxidants prevent caspase 8 activation and Bid cleavage, suggesting that ROS production is an important event mediating this process of apoptosis. However, the participation of uncoupling protein-1, -2, and -3 regulating ROS is unclear because their levels remain unchanged upon insulin treatment for 72 h. Our data suggest that the prolonged hyperinsulinemia might cause insulin resistance through the loss of brown adipose tissue.
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Affiliation(s)
- Almudena Porras
- Departament of Biochemistry and Molecualr Biology II, Biochemistry Institute, Concejo Superior de Investigaciones Cientificas-Unioversidad Complutense de Madrid, Madrid, Spain.
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46
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Hribal ML, Nakae J, Kitamura T, Shutter JR, Accili D. Regulation of insulin-like growth factor-dependent myoblast differentiation by Foxo forkhead transcription factors. J Cell Biol 2003; 162:535-41. [PMID: 12925703 PMCID: PMC2173790 DOI: 10.1083/jcb.200212107] [Citation(s) in RCA: 159] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Insulin-like growth factors promote myoblast differentiation through phosphoinositol 3-kinase and Akt signaling. Akt substrates required for myogenic differentiation are unknown. Forkhead transcription factors of the forkhead box gene, group O (Foxo) subfamily are phosphorylated in an insulin-responsive manner by phosphatidylinositol 3-kinase-dependent kinases. Phosphorylation leads to nuclear exclusion and inactivation. We show that a constitutively active Foxo1 mutant inhibits differentiation of C2C12 cells and prevents myotube differentiation induced by constitutively active Akt. In contrast, a transcriptionally inactive mutant Foxo1 partially rescues inhibition of C2C12 differentiation mediated by wortmannin, but not by rapamycin, and is able to induce aggregation-independent myogenic conversion of teratocarcinoma cells. Inhibition of Foxo expression by siRNA resulted in more efficient differentiation, associated with increased myosin expression. These observations indicate that Foxo proteins are key effectors of Akt-dependent myogenesis.
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Affiliation(s)
- Marta L Hribal
- Russ Berrie Research Pavilion, Rm. 238, 1150 St. Nicholas Avenue, New York, NY 10032, USA
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47
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Santoro MM, Gaudino G, Marchisio PC. The MSP receptor regulates alpha6beta4 and alpha3beta1 integrins via 14-3-3 proteins in keratinocyte migration. Dev Cell 2003; 5:257-71. [PMID: 12919677 DOI: 10.1016/s1534-5807(03)00201-6] [Citation(s) in RCA: 176] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Growth factors, integrins, and the extracellular matrix (ECM) are known to play key roles in epidermal wound healing, although the interplay between these proteins is not fully understood. We show that growth factor macrophage stimulating protein (MSP)- and its receptor Ron-mediated PI3K activation in keratinocytes induces phosphorylation of both Ron and alpha6beta4 integrin at specific 14-3-3 binding sites. Consequently, a Ron/alpha6beta4 complex formed via 14-3-3 binding displaces alpha6beta4 from its location at hemidesmosomes (structures supporting cell adhesion) and relocalizes it to lamellipodia. Concomitant activation of alpha3beta1 and keratinocyte spreading/migration on laminin-5 occurs. Further, MSP-dependent beta4 tyrosine phosphorylation evokes p38 and NF-kappaB signaling required for keratinocyte wound closure. Based on these results, we propose a mechanism based on MSP-Ron-dependent phosphorylation and 14-3-3 association, whereby the function of alpha6beta4 switches from a mechanical adhesive device into a signaling component, and might be critically involved in human epidermal wound healing.
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Affiliation(s)
- Massimo M Santoro
- Department of Medical Sciences, University of Piemonte Orientale "A. Avogadro", 28100, Novara, Italy.
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48
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Hernandez R, Teruel T, Lorenzo M. Insulin and dexamethasone induce GLUT4 gene expression in foetal brown adipocytes: synergistic effect through CCAAT/enhancer-binding protein alpha. Biochem J 2003; 372:617-24. [PMID: 12641495 PMCID: PMC1223428 DOI: 10.1042/bj20030325] [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] [Received: 02/27/2003] [Revised: 03/11/2003] [Accepted: 03/17/2003] [Indexed: 01/02/2023]
Abstract
Treatment of foetal brown adipocytes in primary culture with either dexamethasone or insulin, at physiological concentrations, for 24 h up-regulates the expression of the GLUT4 gene, producing a synergistic effect on mRNA accumulation (20-fold increase), in the amount of protein in the total membrane fraction (8-fold increase) and in the transactivation of a full-promoter GLUT4 -chloramphenicol acetyltransferase gene ( CAT ) construct (7-fold increase). However, GLUT1 expression remains essentially unmodified regardless of the presence of the hormones. As a consequence, exposure of brown adipocytes to dexamethasone and insulin results in a dramatic increase of glucose uptake (12-fold). Dexamethasone induces the expression of CCAAT/enhancer-binding protein (C/EBP) alpha, insulin promotes myocyte enhancer factor-2 DNA-binding activity and both combined produces a significant increase in C/EBPalpha DNA-binding activity. Moreover, co-transfection with a wild-type C/EBPalpha construct transactivates a full-promoter GLUT4 - CAT fusion gene, whereas a dominant-negative C/EBPalpha expression vector impairs the hormonal effects. Our results show that the synergism between insulin and glucocorticoids on glucose uptake is a consequence of the activation of the GLUT4 promoter by the transcription factor C/EBPalpha.
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Affiliation(s)
- Rosario Hernandez
- Departamento de Bioquimica y Biologia Molecular, Facultad de Farmacia, Universidad Complutense, 28040-Madrid, Spain
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49
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Teruel T, Hernandez R, Benito M, Lorenzo M. Rosiglitazone and retinoic acid induce uncoupling protein-1 (UCP-1) in a p38 mitogen-activated protein kinase-dependent manner in fetal primary brown adipocytes. J Biol Chem 2003; 278:263-9. [PMID: 12414803 DOI: 10.1074/jbc.m207200200] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Brown adipose tissue expresses the thermogenic uncoupling protein-1 (UCP-1), which is positively regulated by peroxisome proliferator-activated receptor (PPAR) agonists and retinoids through the activation of the heterodimers PPAR/retinoid X receptor (RXR) and retinoic acid receptor (RAR)/RXR and binding to specific elements in the ucp-1 enhancer. In this study we show that in fetal rat brown adipocyte primary cultures the PPARgamma agonist rosiglitazone (Rosi), as well as retinoic acids 9-cis-retinoic acid and all-trans-retinoic acid also have "extragenic" effects and induce p44/p42 and p38 mitogen-activated protein kinase (p38MAPK) activation. The latter is involved in UCP-1 gene expression, because inhibition of p38MAPK activity with PD169316 impairs the ability of Rosi and retinoids for UCP-1 induction. The inhibitory effects of PD169316 are mimicked by the antioxidant GSH, suggesting a role for reactive oxygenated species (ROS) generation in the increase of UCP-1 expression in response either to Rosi or 9-cis-retinoic acid. Thus, we propose that Rosi and retinoids act as PPAR/RXR and RAR/RXR agonists and also activate p38MAPK. These two coordinated actions could result in a high increase of transcriptional activity on the ucp-1 enhancer and hence on thermogenesis. PPARalpha and gamma agonists but not retinoids also increase UCP-3 expression in fetal brown adipocytes. However, the regulation of UCP-3, which is not involved in thermogenesis, seems to differ from UCP-1 given the fact that is not affected by p38MAPK inhibition.
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Affiliation(s)
- Teresa Teruel
- Departamento de Bioquimica y Biologia Molecular II, Facultad de Farmacia, Universidad Complutense, 28040 Madrid, Spain
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