1
|
Steiman S, Miyake T, McDermott JC. FoxP1 Represses MEF2A in Striated Muscle. Mol Cell Biol 2024; 44:57-71. [PMID: 38483114 PMCID: PMC10950271 DOI: 10.1080/10985549.2024.2323959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 01/23/2024] [Indexed: 03/19/2024] Open
Abstract
Myocyte enhancer factor 2 (MEF2) proteins are involved in multiple developmental, physiological, and pathological processes in vertebrates. Protein-protein interactions underlie the plethora of biological processes impacted by MEF2A, necessitating a detailed characterization of the MEF2A interactome. A nanobody based affinity-purification/mass spectrometry strategy was employed to achieve this goal. Specifically, the MEF2A protein complexes were captured from myogenic lysates using a GFP-tagged MEF2A protein immobilized with a GBP-nanobody followed by LC-MS/MS proteomic analysis to identify MEF2A interactors. After bioinformatic analysis, we further characterized the interaction of MEF2A with a transcriptional repressor, FOXP1. FOXP1 coprecipitated with MEF2A in proliferating myogenic cells which diminished upon differentiation (myotube formation). Ectopic expression of FOXP1 inhibited MEF2A driven myogenic reporter genes (derived from the creatine kinase muscle and myogenin genes) and delayed induction of endogenous myogenin during differentiation. Conversely, FOXP1 depletion enhanced MEF2A transactivation properties and myogenin expression. The FoxP1:MEF2A interaction is also preserved in cardiomyocytes and FoxP1 depletion enhanced cardiomyocyte hypertrophy. FOXP1 prevented MEF2A phosphorylation and activation by the p38MAPK pathway. Overall, these data implicate FOXP1 in restricting MEF2A function in order to avoid premature differentiation in myogenic progenitors and also to possibly prevent re-activation of embryonic gene expression in cardiomyocyte hypertrophy.
Collapse
Affiliation(s)
- Sydney Steiman
- Department of Biology, York University, Toronto, ON, Canada
- Muscle Health Research Centre (MHRC), York University, Toronto, ON, Canada
- Centre for Research in Biomolecular Interactions (CRBI), York University, Toronto, ON, Canada
| | - Tetsuaki Miyake
- Department of Biology, York University, Toronto, ON, Canada
- Muscle Health Research Centre (MHRC), York University, Toronto, ON, Canada
- Centre for Research in Biomolecular Interactions (CRBI), York University, Toronto, ON, Canada
| | - John C. McDermott
- Department of Biology, York University, Toronto, ON, Canada
- Muscle Health Research Centre (MHRC), York University, Toronto, ON, Canada
- Centre for Research in Biomolecular Interactions (CRBI), York University, Toronto, ON, Canada
| |
Collapse
|
2
|
Ehm P, Rietow R, Wegner W, Bußmann L, Kriegs M, Dierck K, Horn S, Streichert T, Horstmann M, Jücker M. SHIP1 Is Present but Strongly Downregulated in T-ALL, and after Restoration Suppresses Leukemia Growth in a T-ALL Xenotransplantation Mouse Model. Cells 2023; 12:1798. [PMID: 37443832 PMCID: PMC10341211 DOI: 10.3390/cells12131798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/23/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Acute lymphoblastic leukemia (ALL) is the most common cause of cancer-related death in children. Despite significantly increased chances of cure, especially for high-risk ALL patients, it still represents a poor prognosis for a substantial fraction of patients. Misregulated proteins in central switching points of the cellular signaling pathways represent potentially important therapeutic targets. Recently, the inositol phosphatase SHIP1 (SH2-containing inositol 5-phosphatase) has been considered as a tumor suppressor in leukemia. SHIP1 serves as an important negative regulator of the PI3K/AKT signaling pathway, which is frequently constitutively activated in primary T-ALL. In contrast to other reports, we show for the first time that SHIP1 has not been lost in T-ALL cells, but is strongly downregulated. Reduced expression of SHIP1 leads to an increased activation of the PI3K/AKT signaling pathway. SHIP1-mRNA expression is frequently reduced in primary T-ALL samples, which is recapitulated by the decrease in SHIP1 expression at the protein level in seven out of eight available T-ALL patient samples. In addition, we investigated the change in the activity profile of tyrosine and serine/threonine kinases after the restoration of SHIP1 expression in Jurkat T-ALL cells. The tyrosine kinase receptor subfamilies of NTRK and PDGFR, which are upregulated in T-ALL subgroups with low SHIP1 expression, are significantly disabled after SHIP1 reconstitution. Lentiviral-mediated reconstitution of SHIP1 expression in Jurkat cells points to a decreased cellular proliferation upon transplantation into NSG mice in comparison to the control cohort. Together, our findings will help to elucidate the complex network of cell signaling proteins, further support a functional role for SHIP1 as tumor suppressor in T-ALL and, much more importantly, show that full-length SHIP1 is expressed in T-ALL samples.
Collapse
Affiliation(s)
- Patrick Ehm
- Institute of Biochemistry and Signal Transduction, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
- Research Institute Children’s Cancer Center Hamburg, Hamburg and Department of Pediatric Oncology and Hematology, University Medical Center, 20246 Hamburg, Germany
| | - Ruth Rietow
- Institute of Biochemistry and Signal Transduction, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
- Research Institute Children’s Cancer Center Hamburg, Hamburg and Department of Pediatric Oncology and Hematology, University Medical Center, 20246 Hamburg, Germany
| | - Wiebke Wegner
- Institute of Biochemistry and Signal Transduction, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| | - Lara Bußmann
- Department of Otorhinolaryngology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- UCCH Kinomics Core Facility, University Cancer Center Hamburg (UCCH), University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Malte Kriegs
- UCCH Kinomics Core Facility, University Cancer Center Hamburg (UCCH), University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
- Center for Oncology, Clinic for Radiation Therapy and Radiation Oncology, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Kevin Dierck
- Research Institute Children’s Cancer Center Hamburg, Hamburg and Department of Pediatric Oncology and Hematology, University Medical Center, 20246 Hamburg, Germany
| | - Stefan Horn
- Research Department Cell and Gene Therapy, Department of Stem Cell Transplantation, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Thomas Streichert
- Institute for Clinical Chemistry, University Hospital Köln, 50937 Cologne, Germany
| | - Martin Horstmann
- Research Institute Children’s Cancer Center Hamburg, Hamburg and Department of Pediatric Oncology and Hematology, University Medical Center, 20246 Hamburg, Germany
| | - Manfred Jücker
- Institute of Biochemistry and Signal Transduction, Center for Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg, Germany
| |
Collapse
|
3
|
Ham AS, Chojnowska K, Tintignac LA, Lin S, Schmidt A, Ham DJ, Sinnreich M, Rüegg MA. mTORC1 signalling is not essential for the maintenance of muscle mass and function in adult sedentary mice. J Cachexia Sarcopenia Muscle 2020; 11:259-273. [PMID: 31697050 PMCID: PMC7015237 DOI: 10.1002/jcsm.12505] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 09/09/2019] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The balance between protein synthesis and degradation (proteostasis) is a determining factor for muscle size and function. Signalling via the mammalian target of rapamycin complex 1 (mTORC1) regulates proteostasis in skeletal muscle by affecting protein synthesis and autophagosomal protein degradation. Indeed, genetic inactivation of mTORC1 in developing and growing muscle causes atrophy resulting in a lethal myopathy. However, systemic dampening of mTORC1 signalling by its allosteric inhibitor rapamycin is beneficial at the organismal level and increases lifespan. Whether the beneficial effect of rapamycin comes at the expense of muscle mass and function is yet to be established. METHODS We conditionally ablated the gene coding for the mTORC1-essential component raptor in muscle fibres of adult mice [inducible raptor muscle-specific knockout (iRAmKO)]. We performed detailed phenotypic and biochemical analyses of iRAmKO mice and compared them with muscle-specific raptor knockout (RAmKO) mice, which lack raptor in developing muscle fibres. We also used polysome profiling and proteomics to assess protein translation and associated signalling in skeletal muscle of iRAmKO mice. RESULTS Analysis at different time points reveal that, as in RAmKO mice, the proportion of oxidative fibres decreases, but slow-type fibres increase in iRAmKO mice. Nevertheless, no significant decrease in body and muscle mass or muscle fibre area was detected up to 5 months post-raptor depletion. Similarly, ex vivo muscle force was not significantly reduced in iRAmKO mice. Despite stable muscle size and function, inducible raptor depletion significantly reduced the expression of key components of the translation machinery and overall translation rates. CONCLUSIONS Raptor depletion and hence complete inhibition of mTORC1 signalling in fully grown muscle leads to metabolic and morphological changes without inducing muscle atrophy even after 5 months. Together, our data indicate that maintenance of muscle size does not require mTORC1 signalling, suggesting that rapamycin treatment is unlikely to negatively affect muscle mass and function.
Collapse
Affiliation(s)
| | | | - Lionel A Tintignac
- Department of Biomedicine, Pharmazentrum, University of Basel, Basel, Switzerland
| | - Shuo Lin
- Biozentrum, University of Basel, Basel, Switzerland
| | - Alexander Schmidt
- Proteomics Core Facility, Biozentrum, University of Basel, Basel, Switzerland
| | - Daniel J Ham
- Biozentrum, University of Basel, Basel, Switzerland
| | - Michael Sinnreich
- Department of Biomedicine, Pharmazentrum, University of Basel, Basel, Switzerland
| | | |
Collapse
|
4
|
Guo B, Zheng C, Cai W, Cheng J, Wang H, Li H, Sun Y, Cui W, Wang Y, Han Y, Lee SMY, Zhang Z. Multifunction of Chrysin in Parkinson's Model: Anti-Neuronal Apoptosis, Neuroprotection via Activation of MEF2D, and Inhibition of Monoamine Oxidase-B. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:5324-5333. [PMID: 27245668 DOI: 10.1021/acs.jafc.6b01707] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Chrysin, a flavonoid compound existing in several plants, is applied as a dietary supplement because of its beneficial effects on general human health and alleviation of neurological disorders. However, mechanisms underlying neuroprotection of chrysin has not been fully elucidated, and the effects of chrysin on the Parkinson's disease (PD) model in vivo have not been investigated. It is here shown that chrysin protects primary granular neurons against 1-methyl-4-phenylpyridinium ion insult via antiapoptosis by reversing the dysregulated expression of Bcl-2, Bax, and caspase 3. The mechanisms also involved activating transcriptional factor myocyte enhancer factor 2D (MEF2D) via regulation of AKT-GSK3β signaling. In this in vivo model of PD, chrysin rescued the dopaminergic neurons loss and alleviated the decrease in dopamine level induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine in mice. Moreover, chrysin markedly inhibited monoamine oxidase-B activity in vitro and in vivo. In conclusion, chrysin exerts beneficial effects to PD, possibly through multitarget mechanisms including antineuronal apoptosis, activation of the AKT-GSK3β/MEF2D pathway, and inhibition of the MAO-B activity.
Collapse
Affiliation(s)
- Baojian Guo
- Institute of New Drug Research and Guangzhou Key Laboratory of Innovative Chemical Drug Research in Cardio-cerebrovascular Diseases, Jinan University College of Pharmacy , Guangzhou, 510632 China
| | - Chengyou Zheng
- Institute of New Drug Research and Guangzhou Key Laboratory of Innovative Chemical Drug Research in Cardio-cerebrovascular Diseases, Jinan University College of Pharmacy , Guangzhou, 510632 China
| | - Wei Cai
- Institute of New Drug Research and Guangzhou Key Laboratory of Innovative Chemical Drug Research in Cardio-cerebrovascular Diseases, Jinan University College of Pharmacy , Guangzhou, 510632 China
| | - Jiehong Cheng
- Institute of New Drug Research and Guangzhou Key Laboratory of Innovative Chemical Drug Research in Cardio-cerebrovascular Diseases, Jinan University College of Pharmacy , Guangzhou, 510632 China
| | - Hongyu Wang
- Institute of New Drug Research and Guangzhou Key Laboratory of Innovative Chemical Drug Research in Cardio-cerebrovascular Diseases, Jinan University College of Pharmacy , Guangzhou, 510632 China
| | - Haitao Li
- State Key Laboratory of Quality Research of Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau , Taipa, Macao, China
| | - Yewei Sun
- Institute of New Drug Research and Guangzhou Key Laboratory of Innovative Chemical Drug Research in Cardio-cerebrovascular Diseases, Jinan University College of Pharmacy , Guangzhou, 510632 China
| | - Wei Cui
- School of Medicine, Ningbo University , Zhejiang, 315211 China
| | - Yuqiang Wang
- Institute of New Drug Research and Guangzhou Key Laboratory of Innovative Chemical Drug Research in Cardio-cerebrovascular Diseases, Jinan University College of Pharmacy , Guangzhou, 510632 China
| | - Yifan Han
- Department of Applied Biology and Chemical Technology, Institute of Modern Chinese Medicine, The Hong Kong Polytechnic University , Hung Hom, Hong Kong, China
| | - Simon Ming-Yuen Lee
- State Key Laboratory of Quality Research of Chinese Medicine and Institute of Chinese Medical Sciences, University of Macau , Taipa, Macao, China
| | - Zaijun Zhang
- Institute of New Drug Research and Guangzhou Key Laboratory of Innovative Chemical Drug Research in Cardio-cerebrovascular Diseases, Jinan University College of Pharmacy , Guangzhou, 510632 China
| |
Collapse
|
5
|
Tanaka Y, Niwa S, Dong M, Farkhondeh A, Wang L, Zhou R, Hirokawa N. The Molecular Motor KIF1A Transports the TrkA Neurotrophin Receptor and Is Essential for Sensory Neuron Survival and Function. Neuron 2016; 90:1215-1229. [DOI: 10.1016/j.neuron.2016.05.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 03/12/2016] [Accepted: 04/28/2016] [Indexed: 01/10/2023]
|
6
|
Xifró X, Rodríguez-Álvarez J. Delineating the factors and cellular mechanisms involved in the survival of cerebellar granule neurons. THE CEREBELLUM 2016; 14:354-9. [PMID: 25596943 DOI: 10.1007/s12311-015-0646-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Cerebellar granule neurons (CGNs) constitute the most abundant neuronal population in the mammalian brain. Their postnatal generation and the feasibility to induce their apoptotic death in vitro make them an excellent model to study the effect of several neurotransmitters and neurotrophins. Here, we first review which factors are involved in the generation and proliferation of CGNs in the external granule layer (EGL) and in the regulation of their differentiation and migration to internal granule layer (IGL). Special attention was given to the role of several neurotrophins and the NMDA subtype of glutamate receptor. Then, using the paradigm of potassium deprivation in cultured CGNs, we address several extracellular factors that promote the survival of CGNs, with particular emphasis on the cellular mechanisms. The role of specific protein kinases leading to the regulation of transcription factors and recent data involving the small G protein family is also discussed. Finally, the participation of some members of Bcl-2 family and the inhibition of mitochondria-related apoptotic pathway is also considered. Altogether, these studies evidence that CGNs are a key model to understand the development and the survival of neuronal populations.
Collapse
Affiliation(s)
- Xavier Xifró
- Departament de Ciències Mèdiques, Facultat de Medicina, Universitat de Girona, C/ Emili Grahit, 77, 17071, Girona, Spain,
| | | |
Collapse
|
7
|
Chen ZW, Liu A, Liu Q, Chen J, Li WM, Chao XJ, Yang Q, Liu PQ, Mao ZX, Pi RB. MEF2D Mediates the Neuroprotective Effect of Methylene Blue Against Glutamate-Induced Oxidative Damage in HT22 Hippocampal Cells. Mol Neurobiol 2016; 54:2209-2222. [PMID: 26941101 DOI: 10.1007/s12035-016-9818-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 02/24/2016] [Indexed: 12/15/2022]
Abstract
Methylene blue (MB) can ameliorate behavioral, neurochemical, and neuropathological impairments in animal models of acute and chronic neurodegenerative disorders, but the underlying mechanism remains unclear. Myocyte enhancer factor 2 (MEF2D) is known to promote neuronal survival in several models, and several survival and death signals converge on MEF2D and regulate its activity. Here, we investigated the role of MEF2D in the neuroprotective effect of MB against glutamate-induced toxicity in HT22 neuronal cells. Our results showed that MB, event at less than 100 nM, improved the viability of HT22 cells exposed to 2 mM glutamate. MB attenuated the mitochondrial impairment and quenches the reactive oxygen species (ROS) induced by glutamate. Surprisingly, MB at 50-200 nM did not affect the Nrf2/HO-1 pathway, an important endogenous anti-oxidative system. Further study showed that MB increased the transcription and translation of MEF2D. In addition, MB upregulated the expression of mitochondrial NADH dehydrogenase 6 (ND6) in a MEF2D-dependent manner. Knockdown of MEF2D abolished both MB-medicated increase of ND6 and MB-induced neuroprotection against glutamate-induced toxicity. Moreover, we showed that MB promoted Akt function activity, suppressed GSK-3β activity, and increased MEF2D level in hippocampus of mice and HT22 cells. These findings for the first time demonstrate that MB protects HT22 neuronal cells against glutamate-induced cell death partially via the regulation of MEF2D-associated survival pathway.
Collapse
Affiliation(s)
- Zi-Wei Chen
- Department of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510080, China.,International Joint Laboratory (SYSU-PolyU HK) of Novel Anti-Dementia Drugs of Guangdong, Guangzhou, 510006, China.,National and Local United Engineering Lab of Druggability and New Drugs Evaluation, Sun Yat-sen University, Guangzhou, 510080, China.,Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.,Zhejiang Pharmaceutical College, Hangzhou, Zhejiang Province, China
| | - Anmin Liu
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120, China
| | - Qingyu Liu
- Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120, China
| | - Jingkao Chen
- Department of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510080, China.,International Joint Laboratory (SYSU-PolyU HK) of Novel Anti-Dementia Drugs of Guangdong, Guangzhou, 510006, China.,National and Local United Engineering Lab of Druggability and New Drugs Evaluation, Sun Yat-sen University, Guangzhou, 510080, China
| | - Wen-Ming Li
- Department of Pharmacology, School of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Xiao-Juan Chao
- Department of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510080, China.,International Joint Laboratory (SYSU-PolyU HK) of Novel Anti-Dementia Drugs of Guangdong, Guangzhou, 510006, China.,National and Local United Engineering Lab of Druggability and New Drugs Evaluation, Sun Yat-sen University, Guangzhou, 510080, China
| | - Qian Yang
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, China
| | - Pei-Qing Liu
- Department of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510080, China.,International Joint Laboratory (SYSU-PolyU HK) of Novel Anti-Dementia Drugs of Guangdong, Guangzhou, 510006, China.,National and Local United Engineering Lab of Druggability and New Drugs Evaluation, Sun Yat-sen University, Guangzhou, 510080, China
| | - Zi-Xu Mao
- Department of Pharmacology, School of Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Rong-Biao Pi
- Department of Pharmacology & Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou, 510080, China. .,International Joint Laboratory (SYSU-PolyU HK) of Novel Anti-Dementia Drugs of Guangdong, Guangzhou, 510006, China. .,National and Local United Engineering Lab of Druggability and New Drugs Evaluation, Sun Yat-sen University, Guangzhou, 510080, China. .,Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China.
| |
Collapse
|
8
|
Inhibition of MEF2A prevents hyperglycemia-induced extracellular matrix accumulation by blocking Akt and TGF-β1/Smad activation in cardiac fibroblasts. Int J Biochem Cell Biol 2015; 69:52-61. [DOI: 10.1016/j.biocel.2015.10.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 09/19/2015] [Accepted: 10/13/2015] [Indexed: 02/07/2023]
|
9
|
Salto R, Vílchez JD, Girón MD, Cabrera E, Campos N, Manzano M, Rueda R, López-Pedrosa JM. β-Hydroxy-β-Methylbutyrate (HMB) Promotes Neurite Outgrowth in Neuro2a Cells. PLoS One 2015; 10:e0135614. [PMID: 26267903 PMCID: PMC4534402 DOI: 10.1371/journal.pone.0135614] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 07/24/2015] [Indexed: 01/11/2023] Open
Abstract
β-Hydroxy-β-methylbutyrate (HMB) has been shown to enhance cell survival, differentiation and protein turnover in muscle, mainly activating phosphoinositide-3-kinase/protein kinase B (PI3K/Akt) and mitogen-activated protein kinases/ extracellular-signal-regulated kinases (MAPK/ERK) signaling pathways. Since these two pathways are related to neuronal survival and differentiation, in this study, we have investigated the neurotrophic effects of HMB in mouse neuroblastoma Neuro2a cells. In Neuro2a cells, HMB promotes differentiation to neurites independent from any effects on proliferation. These effects are mediated by activation of both the PI3K/Akt and the extracellular-signal-regulated kinases (ERK1/2) signaling as demonstrated by the use of specific inhibitors of these two pathways. As myocyte-enhancer factor 2 (MEF2) family of transcription factors are involved in neuronal survival and plasticity, the transcriptional activity and protein levels of MEF2 were also evaluated. HMB promoted MEF2-dependent transcriptional activity mediated by the activation of Akt and ERK1/2 pathways. Furthermore, HMB increases the expression of brain glucose transporters 1 (GLUT1) and 3 (GLUT3), and mTOR phosphorylation, which translates in a higher protein synthesis in Neuro2a cells. Furthermore, Torin1 and rapamycin effects on MEF2 transcriptional activity and HMB-dependent neurite outgrowth support that HMB acts through mTORC2. Together, these findings provide clear evidence to support an important role of HMB in neurite outgrowth.
Collapse
Affiliation(s)
- Rafael Salto
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
- * E-mail:
| | - Jose D. Vílchez
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
| | - María D. Girón
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
| | - Elena Cabrera
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
| | | | | | | | | |
Collapse
|
10
|
Rossman IT, Lin L, Morgan KM, Digiovine M, Van Buskirk EK, Kamdar S, Millonig JH, Dicicco-Bloom E. Engrailed2 modulates cerebellar granule neuron precursor proliferation, differentiation and insulin-like growth factor 1 signaling during postnatal development. Mol Autism 2014; 5:9. [PMID: 24507165 PMCID: PMC3932947 DOI: 10.1186/2040-2392-5-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 01/14/2014] [Indexed: 01/16/2023] Open
Abstract
Background The homeobox transcription factor Engrailed2 (En2) has been studied extensively in neurodevelopment, particularly in the midbrain/hindbrain region and cerebellum, where it exhibits dynamic patterns of expression and regulates cell patterning and morphogenesis. Because of its roles in regulating cerebellar development and evidence of cerebellar pathology in autism spectrum disorder (ASD), we previously examined an ENGRAILED2 association and found evidence to support EN2 as a susceptibility gene, a finding replicated by several other investigators. However, its functions at the cell biological level remain undefined. In the mouse, En2 gene is expressed in granule neuron precursors (GNPs) just as they exit the cell cycle and begin to differentiate, raising the possibility that En2 may modulate these developmental processes. Methods To define En2 functions, we examined proliferation, differentiation and signaling pathway activation in En2 knockout (KO) and wild-type (WT) GNPs in response to a variety of extracellular growth factors and following En2 cDNA overexpression in cell culture. In vivo analyses of cerebellar GNP proliferation as well as responses to insulin-like growth factor-1 (IGF1) treatment were also conducted. Results Proliferation markers were increased in KO GNPs in vivo and in 24-h cultures, suggesting En2 normally serves to promote cell cycle exit. Significantly, IGF1 stimulated greater DNA synthesis in KO than WT cells in culture, a finding associated with markedly increased phospho-S6 kinase activation. Similarly, there was three-fold greater DNA synthesis in the KO cerebellum in response to IGF1 in vivo. On the other hand, KO GNPs exhibited reduced neurite outgrowth and differentiation. Conversely, En2 overexpression increased cell cycle exit and promoted neuronal differentiation. Conclusions In aggregate, our observations suggest that the ASD-associated gene En2 promotes GNP cell cycle exit and differentiation, and modulates IGF1 activity during postnatal cerebellar development. Thus, genetic/epigenetic alterations of EN2 expression may impact proliferation, differentiation and IGF1 signaling as possible mechanisms that may contribute to ASD pathogenesis.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Emanuel Dicicco-Bloom
- Department of Neuroscience & Cell Biology, Robert Wood Johnson Medical School, Rutgers, The State University of New Jersey, 675 Hoes, Lane, Piscataway, NJ 08854, USA.
| |
Collapse
|
11
|
Yao L, Li W, She H, Dou J, Jia L, He Y, Yang Q, Zhu J, Cápiro NL, Walker DI, Pennell KD, Pang Y, Liu Y, Han Y, Mao Z. Activation of transcription factor MEF2D by bis(3)-cognitin protects dopaminergic neurons and ameliorates Parkinsonian motor defects. J Biol Chem 2012; 287:34246-55. [PMID: 22891246 DOI: 10.1074/jbc.m112.367540] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Parkinson disease (PD) is characterized by the selective demise of dopaminergic (DA) neurons in the substantial nigra pars compacta. Dysregulation of transcriptional factor myocyte enhancer factor 2D (MEF2D) has been implicated in the pathogenic process in in vivo and in vitro models of PD. Here, we identified a small molecule bis(3)-cognitin (B3C) as a potent activator of MEF2D. We showed that B3C attenuated the toxic effects of neurotoxin 1-methyl-4-phenylpyridinium (MPP(+)) by activating MEF2D via multiple mechanisms. B3C significantly reduced MPP(+)-induced oxidative stress and potentiated Akt to down-regulate the activity of MEF2 inhibitor glycogen synthase kinase 3β (GSK3β) in a DA neuronal cell line SN4741. Furthermore, B3C effectively rescued MEF2D from MPP(+)-induced decline in both nucleic and mitochondrial compartments. B3C offered SN4741 cells potent protection against MPP(+)-induced apoptosis via MEF2D. Interestingly, B3C also protected SN4741 cells from wild type or mutant A53T α-synuclein-induced cytotoxicity. Using the in vivo PD model of C57BL/6 mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine hydrochloride (MPTP), we showed that B3C maintained redox homeostasis, promoted Akt function activity, and restored MEF2D level in midbrain neurons. Moreover, B3C greatly prevented the loss of tyrosine hydroxylase signal in substantial nigra pars compacta DA neurons and ameliorated behavioral impairments in mice treated with MPTP. Collectedly, our studies identified B3C as a potent neuroprotective agent whose effectiveness relies on its ability to effectively up-regulate MEF2D in DA neurons against toxic stress in models of PD in vitro and in vivo.
Collapse
Affiliation(s)
- Lu Yao
- Institute of Neurobiology, Environment and Genes Related to Diseases, Key Laboratory of Education Ministry, Xi'an Jiaotong University College of Medicine, Xi'an, Shaanxi 710061, China
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Wei G, Yin Y, Li W, Bito H, She H, Mao Z. Calpain-mediated degradation of myocyte enhancer factor 2D contributes to excitotoxicity by activation of extrasynaptic N-methyl-D-aspartate receptors. J Biol Chem 2012; 287:5797-805. [PMID: 22215669 DOI: 10.1074/jbc.m111.260109] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Synaptic and extrasynaptic NMDA receptors (NMDARs) appear to play opposite roles in neuronal survival and death. Here we report the new findings on the dysregulation of survival factor, myocyte enhancer factor 2D (MEF2D), by extrasynaptic NMDARs. Excitotoxicity led to the NMDAR-dependent degradation of MEF2D protein and inhibition of its transactivation activity in mature cortical neurons. The activation of extrasynaptic NMDARs alone was sufficient for degradation of MEF2D. Calpain directly cleaved MEF2D in vitro and blocking this protease activity greatly attenuated NMDAR signaled degradation of MEF2D in neurons. Consistently, inhibition of calpain protected cortical neurons from NMDA-induced excitotoxicity. Furthermore, knockdown of MEF2D sensitized neurons to NMDA-induced excitotoxicity, which was not protected by calpain inhibition. Collectively, these findings suggest that dysregulation of MEF2D by calpain may mediate excitotoxicity via an extrasynaptic NMDAR-dependent manner.
Collapse
Affiliation(s)
- Gengze Wei
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | | | | | | | | | | |
Collapse
|
13
|
Song B, Lai B, Zheng Z, Zhang Y, Luo J, Wang C, Chen Y, Woodgett JR, Li M. Inhibitory phosphorylation of GSK-3 by CaMKII couples depolarization to neuronal survival. J Biol Chem 2010; 285:41122-34. [PMID: 20841359 DOI: 10.1074/jbc.m110.130351] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Glycogen synthase kinase-3 (GSK-3) plays a critical role in neuronal apoptosis. The two mammalian isoforms of the kinase, GSK-3α and GSK-3β, are inhibited by phosphorylation at Ser-21 and Ser-9, respectively. Depolarization, which is vital for neuronal survival, causes both an increase in Ser-21/9 phosphorylation and an inhibition of GSK-3α/β. However, the role of GSK-3 phosphorylation in depolarization-dependent neuron survival and the signaling pathway contributing to GSK-3 phosphorylation during depolarization remain largely unknown. Using several approaches, we showed that both isoforms of GSK-3 are important for mediating neuronal apoptosis. Nonphosphorylatable GSK-3α/β mutants (S21A/S9A) promoted apoptosis, whereas a peptide encompassing Ser-9 of GSK-3β protected neurons in a phosphorylation-dependent manner; these results indicate a critical role for Ser-21/9 phosphorylation on depolarization-dependent neuron survival. We found that Ser-21/9 phosphorylation of GSK-3 was mediated by Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) but not by Akt/PKB, PKA, or p90(RSK). CaMKII associated with and phosphorylated GSK-3α/β. Furthermore, the pro-survival effect of CaMKII was mediated by GSK-3 phosphorylation and inactivation. These findings identify a novel Ca(2+)/calmodulin/CaMKII/GSK-3 pathway that couples depolarization to neuronal survival.
Collapse
Affiliation(s)
- Bin Song
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, 74 Zhongshan Road II, Guangzhou 510080, China
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Muñoz JP, Collao A, Chiong M, Maldonado C, Adasme T, Carrasco L, Ocaranza P, Bravo R, Gonzalez L, Díaz-Araya G, Hidalgo C, Lavandero S. The transcription factor MEF2C mediates cardiomyocyte hypertrophy induced by IGF-1 signaling. Biochem Biophys Res Commun 2009; 388:155-60. [DOI: 10.1016/j.bbrc.2009.07.147] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2009] [Accepted: 07/28/2009] [Indexed: 10/20/2022]
|
15
|
Wang X, She H, Mao Z. Phosphorylation of neuronal survival factor MEF2D by glycogen synthase kinase 3beta in neuronal apoptosis. J Biol Chem 2009; 284:32619-26. [PMID: 19801631 DOI: 10.1074/jbc.m109.067785] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glycogen synthase kinase 3beta (GSK3beta) has been identified to play important roles in neuronal death. Evidence from both in vitro and in vivo studies indicates that increased GSK3beta activity contributes to neurodegeneration and to the pathogenesis of Alzheimer disease. But the molecular mechanisms that underlie GSK3beta-mediated neurotoxicity remain poorly understood. We reported here that myocyte enhancer factor 2D (MEF2D), a nuclear transcription factor known to promote neuronal survival, is directly phosphorylated by GSK3beta. Our data showed that phosphorylation of MEF2D by GSK3beta at three specific residues in its transactivation domain inhibits MEF2D transcriptional activity. Withdrawal of neuronal activity in cerebellar granule neurons activated GSK3beta in the nucleus, leading to GSK3beta-dependent inhibition of MEF2 function. This inhibition contributed to GSK3beta-mediated neuronal toxicity. Overexpression of MEF2D mutant that is resistant to GSK3beta inhibition protected cerebellar granule neurons from either GSK3beta activation- or neuronal activity deprivation-induced toxicity. These results identify survival factor MEF2D as a novel downstream effector targeted by GSK3beta and define a molecular link between activation of GSK3beta and neuronal survival machinery which may underlie in part GSK3beta-mediated neurotoxicity.
Collapse
Affiliation(s)
- Xuemin Wang
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | | | | |
Collapse
|
16
|
Kim BJ, Takamoto N, Yan J, Tsai SY, Tsai MJ. Chicken Ovalbumin Upstream Promoter-Transcription Factor II (COUP-TFII) regulates growth and patterning of the postnatal mouse cerebellum. Dev Biol 2008; 326:378-91. [PMID: 19041640 DOI: 10.1016/j.ydbio.2008.11.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Revised: 10/29/2008] [Accepted: 11/03/2008] [Indexed: 01/26/2023]
Abstract
COUP-TFII (also known as Nr2f2), a member of the nuclear orphan receptor superfamily, is expressed in several regions of the central nervous system (CNS), including the ventral thalamus, hypothalamus, midbrain, pons, and spinal cord. To address the function of COUP-TFII in the CNS, we generated conditional COUP-TFII knockout mice using a tissue-specific NSE-Cre recombinase. Ablation of COUP-TFII in the brain resulted in malformation of the lobule VI in the cerebellum and a decrease in differentiation of cerebellar neurons and cerebellar growth. The decrease in cerebellar growth in NSE(Cre/+)/CII(F/F) mice is due to reduced proliferation and increased apoptosis in granule cell precursors (GCPs). Additional studies demonstrated that insulin like growth factor 1 (IGF-1) expression was reduced in the cerebellum of NSE(Cre/+)/CII(F/F) mice, thereby leading to decreased Akt1 and GSK-3beta activities, and the reduced expression of mTOR. Using ChIP assays, we demonstrated that COUP-TFII was recruited to the promoter region of IGF-1 in a Sp1-dependent manner. In addition, dendritic branching of Purkinje cells was decreased in the mutant mice. Thus, our results indicate that COUP-TFII regulates growth and maturation of the mouse postnatal cerebellum through modulation of IGF-1 expression.
Collapse
Affiliation(s)
- Bum Jun Kim
- Department of Molecular and Cellular Biology and Development Program, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | | | |
Collapse
|
17
|
Bentzinger CF, Romanino K, Cloëtta D, Lin S, Mascarenhas JB, Oliveri F, Xia J, Casanova E, Costa CF, Brink M, Zorzato F, Hall MN, Rüegg MA. Skeletal muscle-specific ablation of raptor, but not of rictor, causes metabolic changes and results in muscle dystrophy. Cell Metab 2008; 8:411-24. [PMID: 19046572 DOI: 10.1016/j.cmet.2008.10.002] [Citation(s) in RCA: 486] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2008] [Revised: 08/15/2008] [Accepted: 10/07/2008] [Indexed: 11/18/2022]
Abstract
Mammalian target of rapamycin (mTOR) is a central controller of cell growth. mTOR assembles into two distinct multiprotein complexes called mTOR complex 1 (mTORC1) and mTORC2. Here we show that the mTORC1 component raptor is critical for muscle function and prolonged survival. In contrast, muscles lacking the mTORC2 component rictor are indistinguishable from wild-type controls. Raptor-deficient muscles become progressively dystrophic, are impaired in their oxidative capacity, and contain increased glycogen stores, but they express structural components indicative of oxidative muscle fibers. Biochemical analysis indicates that these changes are probably due to loss of activation of direct downstream targets of mTORC1, downregulation of genes involved in mitochondrial biogenesis, including PGC1alpha, and hyperactivation of PKB/Akt. Finally, we show that activation of PKB/Akt does not require mTORC2. Together, these results demonstrate that muscle mTORC1 has an unexpected role in the regulation of the metabolic properties and that its function is essential for life.
Collapse
|
18
|
Teos LY, Zhao A, Alvin Z, Laurence GG, Li C, Haddad GE. Basal and IGF-I-dependent regulation of potassium channels by MAP kinases and PI3-kinase during eccentric cardiac hypertrophy. Am J Physiol Heart Circ Physiol 2008; 295:H1834-45. [PMID: 18757484 DOI: 10.1152/ajpheart.321.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The potassium channels I(K) and I(K1), responsible for the action potential repolarization and resting potential respectively, are altered during cardiac hypertrophy. The activation of insulin-like growth factor-I (IGF-I) during hypertrophy may affect channel activity. The aim was to examine the modulatory effects of IGF-I on I(K) and I(K1) through mitogen-activated protein kinase (MAPK) and phosphatidylinositol 3-kinase (PI3K) pathways during hypertrophy. With the use of specific inhibitors for ERK1/2 (PD98059), p38 MAPK (SB203580) and PI3K/Akt (LY294002), Western blot and whole cell patch-clamp were conducted on sham and aorto-caval shunt-induced hypertrophy adult rat myocytes. Basal activation levels of MAPKs and Akt were increased during hypertrophy. Acute IGF-I (10(-8) M) enhanced basal activation levels of these kinases in normal hearts but only those of Akt in hypertrophied ones. I(K) and I(K1) activities were lowered by IGF-I. Inhibition of ERK1/2, p38 MAPK, or Akt reduced basal I(K) activity by 70, 32, or 50%, respectively, in normal cardiomyocytes vs. 53, 34, or 52% in hypertrophied ones. However, basal activity of I(K1) was reduced by 45, 48, or 45% in the former vs. 63, 43, or 24% in the latter. The inhibition of either MAPKs or Akt alleviated IGF-I effects on I(K) and I(K1). We conclude that basal I(K) and I(K1) are positively maintained by steady-state Akt and ERK activities. K+ channels seem to be regulated in a dichotomic manner by acutely stimulated MAPKs and Akt. Eccentric cardiac hypertrophy may be associated with a change in the regulation of the steady-state basal activities of K+ channels towards MAPKs, while that of the acute IGF-I-stimulated ones toward Akt.
Collapse
Affiliation(s)
- Leyla Y Teos
- Department of Physiology and Biophysics, College of Medicine, Howard University, Washington, DC 20059, USA
| | | | | | | | | | | |
Collapse
|