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Khudayberdiev S, Weiss K, Heinze A, Colombaretti D, Trausch N, Linne U, Rust MB. The actin-binding protein CAP1 represses MRTF-SRF-dependent gene expression in mouse cerebral cortex. Sci Signal 2024; 17:eadj0032. [PMID: 38713765 DOI: 10.1126/scisignal.adj0032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 04/15/2024] [Indexed: 05/09/2024]
Abstract
Serum response factor (SRF) is an essential transcription factor for brain development and function. Here, we explored how an SRF cofactor, the actin monomer-sensing myocardin-related transcription factor MRTF, is regulated in mouse cortical neurons. We found that MRTF-dependent SRF activity in vitro and in vivo was repressed by cyclase-associated protein CAP1. Inactivation of the actin-binding protein CAP1 reduced the amount of actin monomers in the cytoplasm, which promoted nuclear MRTF translocation and MRTF-SRF activation. This function was independent of cofilin1 and actin-depolymerizing factor, and CAP1 loss of function in cortical neurons was not compensated by endogenous CAP2. Transcriptomic and proteomic analyses of cerebral cortex lysates from wild-type and Cap1 knockout mice supported the role of CAP1 in repressing MRTF-SRF-dependent signaling in vivo. Bioinformatic analysis identified likely MRTF-SRF target genes, which aligned with the transcriptomic and proteomic results. Together with our previous studies that implicated CAP1 in axonal growth cone function as well as the morphology and plasticity of excitatory synapses, our findings establish CAP1 as a crucial actin regulator in the brain relevant for formation of neuronal networks.
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Affiliation(s)
- Sharof Khudayberdiev
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
| | - Kerstin Weiss
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Anika Heinze
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Dalila Colombaretti
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Nathan Trausch
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Uwe Linne
- Department of Chemistry, Philipps-University Marburg, 35032 Marburg, Germany
| | - Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
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Li J, Kalev‐Zylinska ML. Advances in molecular characterization of pediatric acute megakaryoblastic leukemia not associated with Down syndrome; impact on therapy development. Front Cell Dev Biol 2023; 11:1170622. [PMID: 37325571 PMCID: PMC10267407 DOI: 10.3389/fcell.2023.1170622] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 05/19/2023] [Indexed: 06/17/2023] Open
Abstract
Acute megakaryoblastic leukemia (AMKL) is a rare subtype of acute myeloid leukemia (AML) in which leukemic blasts have megakaryocytic features. AMKL makes up 4%-15% of newly diagnosed pediatric AML, typically affecting young children (less than 2 years old). AMKL associated with Down syndrome (DS) shows GATA1 mutations and has a favorable prognosis. In contrast, AMKL in children without DS is often associated with recurrent and mutually exclusive chimeric fusion genes and has an unfavorable prognosis. This review mainly summarizes the unique features of pediatric non-DS AMKL and highlights the development of novel therapies for high-risk patients. Due to the rarity of pediatric AMKL, large-scale multi-center studies are needed to progress molecular characterization of this disease. Better disease models are also required to test leukemogenic mechanisms and emerging therapies.
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Affiliation(s)
- Jixia Li
- Blood and Cancer Biology Laboratory, Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
- Department of Laboratory Medicine, School of Medicine, Foshan University, Foshan, China
| | - Maggie L. Kalev‐Zylinska
- Blood and Cancer Biology Laboratory, Department of Molecular Medicine and Pathology, University of Auckland, Auckland, New Zealand
- Haematology Laboratory, Department of Pathology and Laboratory Medicine, Auckland City Hospital, Auckland, New Zealand
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Phosphorylation Signals Downstream of Dopamine Receptors in Emotional Behaviors: Association with Preference and Avoidance. Int J Mol Sci 2022; 23:ijms231911643. [PMID: 36232945 PMCID: PMC9570387 DOI: 10.3390/ijms231911643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 11/09/2022] Open
Abstract
Dopamine regulates emotional behaviors, including rewarding and aversive behaviors, through the mesolimbic dopaminergic pathway, which projects dopamine neurons from the ventral tegmental area to the nucleus accumbens (NAc). Protein phosphorylation is critical for intracellular signaling pathways and physiological functions, which are regulated by neurotransmitters in the brain. Previous studies have demonstrated that dopamine stimulated the phosphorylation of intracellular substrates, such as receptors, ion channels, and transcription factors, to regulate neuronal excitability and synaptic plasticity through dopamine receptors. We also established a novel database called KANPHOS that provides information on phosphorylation signals downstream of monoamines identified by our kinase substrate screening methods, including dopamine, in addition to those reported in the literature. Recent advances in proteomics techniques have enabled us to clarify the mechanisms through which dopamine controls rewarding and aversive behaviors through signal pathways in the NAc. In this review, we discuss the intracellular phosphorylation signals regulated by dopamine in these two emotional behaviors.
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Tang G, Yu C, Xiang K, Gao M, Liu Z, Yang B, Yang M, Zhao S. Inhibition of ANXA2 regulated by SRF attenuates the development of severe acute pancreatitis by inhibiting the NF-κB signaling pathway. Inflamm Res 2022; 71:1067-1078. [PMID: 35900381 DOI: 10.1007/s00011-022-01609-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Acute pancreatitis (AP) is an inflammatory process of the pancreas resulting from biliary obstruction or alcohol consumption. Approximately, 10-20% of AP can evolve into severe AP (SAP). In this study, we sought to explore the physiological roles of the transcription factor serum response factor (SRF), annexin A2 (ANXA2), and nuclear factor-kappaB (NF-κB) in SAP. METHODS C57BL/6 mice and rat pancreatic acinar cells (AR42J) were used to establish an AP model in vivo and in vitro by cerulein with or without lipopolysaccharide (LPS). Production of pro-inflammatory cytokines (IL-1β and TNF-α) were examined by ELISA and immunoblotting analysis. Hematoxylin and eosin (HE) staining and TUNEL staining were performed to evaluate pathological changes in the course of AP. Apoptosis was examined by flow cytometric and immunoblotting analysis. Molecular interactions were tested by dual luciferase reporter, ChIP, and Co-IP assays. RESULTS ANXA2 was overexpressed in AP and correlated to the severity of AP. ANXA2 knockdown rescued pancreatic acinar cells against inflammation and apoptosis induced by cerulein with or without LPS. Mechanistic investigations revealed that SRF bound with the ANXA2 promoter region and repressed its expression. ANXA2 could activate the NF-κB signaling pathway by inducing the nuclear translocation of p50. SRF-mediated transcriptional repression of ANXA2-protected pancreatic acinar cells against AP-like injury through repressing the NF-κB signaling pathway. CONCLUSION Our study highlighted a regulatory network consisting of SRF, ANXA2, and NF-κB that was involved in AP progression, possibly providing some novel targets for treating SAP.
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Affiliation(s)
- Guanxiu Tang
- The Department of Gerontology, The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Can Yu
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Kaimin Xiang
- The Department of Gastrointestinal Surgery, The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Min Gao
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Zuoliang Liu
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Bingchang Yang
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Mingshi Yang
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China
| | - Shangping Zhao
- The Department of Intensive Care Unit (ICU), The Third Xiangya Hospital of Central South University, No. 138, Tongzipo Road, Yuelu District, Changsha, 410013, Hunan Province, People's Republic of China.
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Tabuchi A, Ihara D. SRF in Neurochemistry: Overview of Recent Advances in Research on the Nervous System. Neurochem Res 2022; 47:2545-2557. [PMID: 35668335 DOI: 10.1007/s11064-022-03632-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/20/2022] [Accepted: 05/07/2022] [Indexed: 10/18/2022]
Abstract
Serum response factor (SRF) is a representative transcription factor that plays crucial roles in various biological phenomena by regulating immediate early genes (IEGs) and genes related to cell morphology and motility, among others. Over the years, the signal transduction pathways activating SRF have been clarified and SRF-target genes have been identified. In this overview, we initially briefly summarize the basic biology of SRF and its cofactors, ternary complex factor (TCF) and megakaryoblastic leukemia (MKL)/myocardin-related transcription factor (MRTF). Progress in the generation of nervous system-specific knockout (KO) or genetically modified mice as well as genetic analyses over the last few decades has not only identified novel SRF-target genes but also highlighted the neurochemical importance of SRF and its cofactors. Therefore, here we next present the phenotypes of mice with nervous system-specific KO of SRF or its cofactors by depicting recent findings associated with brain development, plasticity, epilepsy, stress response, and drug addiction, all of which result from function or dysfunction of the SRF axis. Last, we develop a hypothesis regarding the possible involvement of SRF and its cofactors in human neurological disorders including neurodegenerative, psychiatric, and neurodevelopmental diseases. This overview should deepen our understanding, highlight promising future directions for developing novel therapeutic strategies, and lead to illumination of the mechanisms underlying higher brain functions based on neuronal structure and function.
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Affiliation(s)
- Akiko Tabuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Daisuke Ihara
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
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Wang N, Xi J, Lan C, Wu Y, Zhu Y, Zuo X, Zhang Y. Association between IKBKAP polymorphisms and Hirschsprung's disease susceptibility in Chinese children. Transl Pediatr 2022; 11:789-796. [PMID: 35800263 PMCID: PMC9253937 DOI: 10.21037/tp-21-550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 04/22/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Hirschsprung's disease (HSCR) is a rare congenital disease in which enteric nervous system (ENS) in the distal intestine is absent. HSCR is a disease involving genetic factors and environmental factors. Despite a series of genes have been revealed to contribute to HSCR, many HSCR associated genes were yet not identified. Previous studies had identified that a potential susceptibility gene of HSCR was an inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase complex-associated protein (IKBKAP). The study aimed to explore the association of genetic variants in IKBKAP and HSCR susceptibility in southern Chinese children. METHODS Single nucleotide polymorphism (SNPs) were genotyped by the Mass ARRAY iPLEX Gold system (Sequenom, San Diego, CA, USA) on all samples, which included 1,470 HSCR children (cases) and 1,473 healthy children (controls). The associations between SNPs and HSCR or clinical subtypes were assessed by comparing their allele frequencies in corresponding case and control samples. Different genetic models, including additive, recessive, and dominant models, were tested using PLINK 1.9 software. RESULTS Further subgroup analysis revealed rs2275630 as a total colonic aganglionosis (TCA)-specific susceptibility locus. The present study is the first to indicate that IKBKAP rs2275630 were associated with HSCR susceptibility, especially in TCA patients. CONCLUSIONS We conclude that IKBKAP rs2275630 is a susceptibility gene of HSCR.
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Affiliation(s)
- Ning Wang
- Department of Pediatric Surgery, Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Jiaojiao Xi
- Department of Pediatric Surgery, Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Chaoting Lan
- Department of Pediatrics, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Yuxin Wu
- Department of Pediatrics, The First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Yun Zhu
- Department of Pediatric Surgery, Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Xiaoyu Zuo
- Department of Pediatric Surgery, Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
| | - Yan Zhang
- Department of Pediatric Surgery, Guangzhou Institute of Pediatrics, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, China
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Kuchler O, Gerlach J, Vomhof T, Hettich J, Steinmetz J, Gebhardt JCM, Michaelis J, Knöll B. Single-molecule tracking (SMT) and localization of SRF and MRTF transcription factors during neuronal stimulation and differentiation. Open Biol 2022; 12:210383. [PMID: 35537478 PMCID: PMC9090491 DOI: 10.1098/rsob.210383] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
In cells, proteins encoded by the same gene do not all behave uniformly but engage in functional subpopulations induced by spatial or temporal segregation. While conventional microscopy has limitations in revealing such spatial and temporal diversity, single-molecule tracking (SMT) microscopy circumvented this problem and allows for high-resolution imaging and quantification of dynamic single-molecule properties. Particularly in the nucleus, SMT has identified specific DNA residence times of transcription factors (TFs), DNA-bound TF fractions and positions of transcriptional hot-spots upon cell stimulation. By contrast to cell stimulation, SMT has not been employed to follow dynamic TF changes along stages of cell differentiation. Herein, we analysed the serum response factor (SRF), a TF involved in the differentiation of many cell types to study nuclear single-molecule dynamics in neuronal differentiation. Our data in living mouse hippocampal neurons show dynamic changes in SRF DNA residence time and SRF DNA-bound fraction between the stages of adhesion, neurite growth and neurite differentiation in axon and dendrites. Using TALM (tracking and localization microscopy), we identified nuclear positions of SRF clusters and observed changes in their numbers and size during differentiation. Furthermore, we show that the SRF cofactor MRTF-A (myocardin-related TF or MKL1) responds to cell activation by enhancing the long-bound DNA fraction. Finally, a first SMT colocalization study of two proteins was performed in living cells showing enhanced SRF/MRTF-A colocalization upon stimulation. In summary, SMT revealed modulation of dynamic TF properties during cell stimulation and differentiation.
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Affiliation(s)
- Oliver Kuchler
- Institute of Neurobiochemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany,Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Jule Gerlach
- Institute of Neurobiochemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany,Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Thomas Vomhof
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Johannes Hettich
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Julia Steinmetz
- Department of Statistics, TU Dortmund University, August-Schmidt Straße 1, 44227 Dortmund, Germany
| | | | - Jens Michaelis
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Bernd Knöll
- Institute of Neurobiochemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
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Li SZ, Zhang ZY, Chen J, Dong MY, Du XH, Gao J, Shu QP, Li C, Liang XY, Ding ZH, Du RL, Wang J, Zhang XD. NLK is required for Ras/ERK/SRF/ELK signaling to tune skeletal muscle development by phosphorylating SRF and antagonizing the SRF/MKL pathway. Cell Death Dis 2022; 8:4. [PMID: 35013153 PMCID: PMC8748963 DOI: 10.1038/s41420-021-00774-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/15/2021] [Accepted: 11/25/2021] [Indexed: 11/23/2022]
Abstract
Serum response factor (SRF) regulates differentiation and proliferation by binding to RhoA-actin-activated MKL or Ras-MAPK-activated ELK transcriptional coactivators, but the molecular mechanisms responsible for SRF regulation remain unclear. Here, we show that Nemo-like kinase (NLK) is required for the promotion of SRF/ELK signaling in human and mouse cells. NLK was found to interact with and phosphorylate SRF at serine residues 101/103, which in turn enhanced the association between SRF and ELK. The enhanced affinity of SRF/ELK antagonized the SRF/MKL pathway and inhibited mouse myoblast differentiation in vitro. In a skeletal muscle-specific Nlk conditional knockout mouse model, forming muscle myofibers underwent hypertrophic growth, resulting in an increased muscle and body mass phenotype. We propose that both phosphorylation of SRF by NLK and phosphorylation of ELKs by MAPK are required for RAS/ELK signaling, confirming the importance of this ancient pathway and identifying an important role for NLK in modulating muscle development in vivo.
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Affiliation(s)
- Shang-Ze Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China.,School of Medicine, Chongqing University, 400030, Chongqing, China
| | - Ze-Yan Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China
| | - Jie Chen
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China
| | - Ming-You Dong
- Reproductive genetics laboratory, Affiliated hospital of Youjiang Medical University for Nationalities, 533000, Baise, Guangxi, China
| | - Xue-Hua Du
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China
| | - Jie Gao
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China
| | - Qi-Peng Shu
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China
| | - Chao Li
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China
| | - Xin-Yi Liang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China
| | - Zhi-Hao Ding
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China
| | - Run-Lei Du
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China
| | - Junli Wang
- School of Medicine, Chongqing University, 400030, Chongqing, China. .,Reproductive genetics laboratory, Affiliated hospital of Youjiang Medical University for Nationalities, 533000, Baise, Guangxi, China.
| | - Xiao-Dong Zhang
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, 430072, Wuhan, Hubei, China. .,Reproductive genetics laboratory, Affiliated hospital of Youjiang Medical University for Nationalities, 533000, Baise, Guangxi, China.
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Tabuchi A, Ihara D. Regulation of Dendritic Synaptic Morphology and Transcription by the SRF Cofactor MKL/MRTF. Front Mol Neurosci 2021; 14:767842. [PMID: 34795561 PMCID: PMC8593110 DOI: 10.3389/fnmol.2021.767842] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/11/2021] [Indexed: 12/12/2022] Open
Abstract
Accumulating evidence suggests that the serum response factor (SRF) cofactor megakaryoblastic leukemia (MKL)/myocardin-related transcription factor (MRTF) has critical roles in many physiological and pathological processes in various cell types. MKL/MRTF molecules comprise MKL1/MRTFA and MKL2/MRTFB, which possess actin-binding motifs at the N-terminus, and SRF-binding domains and a transcriptional activation domain (TAD) at the C-terminus. Several studies have reported that, in association with actin rearrangement, MKL/MRTF translocates from the cytoplasm to the nucleus, where it regulates SRF-mediated gene expression and controls cell motility. Therefore, it is important to elucidate the roles of MKL/MRTF in the nervous system with regard to its structural and functional regulation by extracellular stimuli. We demonstrated that MKL/MRTF is highly expressed in the brain, especially the synapses, and is involved in dendritic complexity and dendritic spine maturation. In addition to the positive regulation of dendritic complexity, we identified several MKL/MRTF isoforms that negatively regulate dendritic complexity in cortical neurons. We found that the MKL/MRTF isoforms were expressed differentially during brain development and the impacts of these isoforms on the immediate early genes including Arc/Arg3.1, were different. Here, we review the roles of MKL/MRTF in the nervous system, with a special focus on the MKL/MRTF-mediated fine-tuning of neuronal morphology and gene transcription. In the concluding remarks, we briefly discuss the future perspectives and the possible involvement of MKL/MRTF in neurological disorders such as schizophrenia and autism spectrum disorder.
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Affiliation(s)
- Akiko Tabuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Daisuke Ihara
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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Integration in oncogenes plays only a minor role in determining the in vivo distribution of HIV integration sites before or during suppressive antiretroviral therapy. PLoS Pathog 2021; 17:e1009141. [PMID: 33826675 PMCID: PMC8055010 DOI: 10.1371/journal.ppat.1009141] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 04/19/2021] [Accepted: 03/24/2021] [Indexed: 12/11/2022] Open
Abstract
HIV persists during antiretroviral therapy (ART) as integrated proviruses in cells descended from a small fraction of the CD4+ T cells infected prior to the initiation of ART. To better understand what controls HIV persistence and the distribution of integration sites (IS), we compared about 15,000 and 54,000 IS from individuals pre-ART and on ART, respectively, with approximately 395,000 IS from PBMC infected in vitro. The distribution of IS in vivo is quite similar to the distribution in PBMC, but modified by selection against proviruses in expressed genes, by selection for proviruses integrated into one of 7 specific genes, and by clonal expansion. Clones in which a provirus integrated in an oncogene contributed to cell survival comprised only a small fraction of the clones persisting in on ART. Mechanisms that do not involve the provirus, or its location in the host genome, are more important in determining which clones expand and persist. In HIV-infected individuals, a small fraction of the infected cells persist and divide. This reservoir persists during fully suppressive ART and can rekindle the infection if ART is discontinued. Because the number of possible sites of HIV DNA integration is very large, each infected cell, and all of its descendants, can be identified by the site where the provirus is integrated (IS). To understand the selective forces that determine the fates of infected cells in vivo, we compared the distribution of HIV IS in freshly-infected cells to cells from HIV-infected donors sampled both before and during ART. We found that, as previously reported, integration favors highly-expressed genes. However, over time, the fraction of cells with proviruses integrated in highly-expressed genes decreases, implying that they grow less well. There are exceptions to this broad negative selection. When a provirus is integrated in a specific region in one of seven genes, the proviruses affect the expression of the target gene, promoting growth and/or survival of the cell. Although this effect is striking, it is only a minor component of the forces that promote the growth and survival of the population of infected cells during ART.
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Kermorgant M, Ben Salem J, Iacovoni JS, Calise D, Dahan L, Guiard BP, Lopez S, Lairez O, Lasbories A, Nasr N, Pavy Le‐Traon A, Beaudry F, Senard J, Arvanitis DN. Cardiac sensory afferents modulate susceptibility to anxio-depressive behaviour in a mouse model of chronic heart failure. Acta Physiol (Oxf) 2021; 231:e13601. [PMID: 33316126 DOI: 10.1111/apha.13601] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 11/23/2020] [Accepted: 12/09/2020] [Indexed: 12/20/2022]
Abstract
AIM Impairments in cerebral structure and cognitive performance in chronic heart failure (CHF) are critical components of its comorbidity spectrum. Autonomic afferents that arise from cardiac sensory fibres show enhanced activity with CHF. Desensitization of these fibres by local application of resiniferatoxin (RTX) during myocardial infarction (MI) is known to prevent cardiac hypertrophy, sympathetic hyperactivity and CHF. Whether these afferents mediate cerebral allostasis is unknown. METHODS CHF was induced by myocardial infarction. To evaluate if cardiac afferents contribute to cerebral allostasis, RTX was acutely applied to the pericardial space in controls (RTX) and in MI treated animals (MI/RTX). Subjects were then evaluated in a series of behavioural tests recapitulating different symptoms of depressive disorders. Proteomics of the frontal cortices (FC) was performed to identify contributing proteins and pathways responsible for behavioural allostasis. RESULTS Desensitization of cardiac afferents relieves hallmarks of an anxio/depressive-like state in mice. Unique protein signatures and regulatory pathways in FCs isolated from each treatment reveal the degree of complexity inherent in the FC response to stresses originating in the heart. While cortices from the combined treatment (MI/RTX) did not retain protein signatures from the individual treatment groups, all three groups suffer dysregulation in circadian entrainment. CONCLUSION CHF is comorbid with an anxio/depressive-like state and ablation of cardiac afferents relieves the despair phenotype. The strikingly different proteomic profiles observed in FCs suggest that MI and RTX lead to unique brain-signalling patterns and that the combined treatment, potentially through destructive interference mechanisms, most closely resembles controls.
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Affiliation(s)
- Marc Kermorgant
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
| | - Jennifer Ben Salem
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Groupe de Recherche en Pharmacologie Animale du Québec (GREPAQ) Département de Biomédecine Vétérinaire Faculté de Médecine Vétérinaire Université de Montréal Saint Hyacinthe QC Canada
- Centre de recherche sur le cerveau et l’apprentissage (CIRCA) Université de Montréal Montréal QC Canada
| | - Jason S. Iacovoni
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
| | - Denis Calise
- INSERM DR Midi‐Pyrénées LimousinCentre Régional d’Exploration Fonctionnelle et Ressources Expérimentales Service Microchirurgie, (CREFRE‐US06, Rangueil) Toulouse France
| | - Lionel Dahan
- Centre de Recherches sur la Cognition Animale Centre de Biologie Intégrative Université de Toulouse Toulouse France
- CNRSUniversité de Toulouse III Toulouse France
| | - Bruno P. Guiard
- Centre de Recherches sur la Cognition Animale Centre de Biologie Intégrative Université de Toulouse Toulouse France
- CNRSUniversité de Toulouse III Toulouse France
| | - Sébastien Lopez
- Centre de Recherches sur la Cognition Animale Centre de Biologie Intégrative Université de Toulouse Toulouse France
- CNRSUniversité de Toulouse III Toulouse France
| | - Olivier Lairez
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Fédération des services de cardiologie Hôpital RangueilUniversité de Toulouse III Toulouse France
| | - Antoine Lasbories
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
| | - Nathalie Nasr
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Département de Neurologie et Institut des Neurosciences CHU de ToulouseUniversité de Toulouse III Toulouse France
| | - Anne Pavy Le‐Traon
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Département de Neurologie et Institut des Neurosciences CHU de ToulouseUniversité de Toulouse III Toulouse France
| | - Francis Beaudry
- Groupe de Recherche en Pharmacologie Animale du Québec (GREPAQ) Département de Biomédecine Vétérinaire Faculté de Médecine Vétérinaire Université de Montréal Saint Hyacinthe QC Canada
- Centre de recherche sur le cerveau et l’apprentissage (CIRCA) Université de Montréal Montréal QC Canada
| | - Jean‐Michel Senard
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- Département de Neurologie et Institut des Neurosciences CHU de ToulouseUniversité de Toulouse III Toulouse France
- Service de Pharmacologie Clinique CHU de ToulouseUniversité de Toulouse III Toulouse France
| | - Dina N Arvanitis
- INSERM DR Midi‐Pyrénées LimousinInstitut des Maladies Métaboliques et Cardiovasculaires (I2MC) UMR1048Université de Toulouse III Toulouse France
- CNRSUniversité de Toulouse III Toulouse France
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12
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Ariza A, Funahashi Y, Kozawa S, Omar Faruk M, Nagai T, Amano M, Kaibuchi K. Dynamic subcellular localization and transcription activity of the SRF cofactor MKL2 in the striatum are regulated by MAPK. J Neurochem 2021; 157:1774-1788. [PMID: 33449379 DOI: 10.1111/jnc.15303] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 01/05/2021] [Accepted: 01/08/2021] [Indexed: 01/16/2023]
Abstract
Dopamine type 1 receptor (D1R) signaling activates protein kinase A (PKA), which then activates mitogen-activated protein kinase (MAPK) through Rap1, in striatal medium spiny neurons (MSNs). MAPK plays a pivotal role in reward-related behavior through the activation of certain transcription factors. How D1R signaling regulates behavior through transcription factors remains largely unknown. CREB-binding protein (CBP) promotes transcription through hundreds of different transcription factors and is also important for reward-related behavior. To identify transcription factors regulated by dopamine signaling in MSNs, we performed a phosphoproteomic analysis using affinity beads coated with CBP. We obtained approximately 40 novel candidate proteins in the striatum of the C57BL/6 mouse brain after cocaine administration. Among them, the megakaryoblastic leukemia-2 (MKL2) protein, a transcriptional coactivator of serum response factor (SRF), was our focus. We found that the interaction between CBP and MKL2 was increased by cocaine administration. Additionally, MKL2, CBP and SRF formed a ternary complex in vivo. The C-terminal domain of MKL2 interacted with CBP-KIX and was phosphorylated by MAPK in COS7 cells. The activation of PKA-MAPK signaling induced the nuclear localization of MKL2 and increased SRF-dependent transcriptional activity in neurons. These results demonstrate that dopamine signaling regulates the interaction of MKL2 with CBP in a phosphorylation-dependent manner and thereby controls SRF-dependent gene expression. Cover Image for this issue: https://doi.org/10.1111/jnc.15067.
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Affiliation(s)
- Anthony Ariza
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Yasuhiro Funahashi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.,Research Project for Neural and Tumor Signaling, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
| | - Sachi Kozawa
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Md Omar Faruk
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Taku Nagai
- Division of Behavioral Neuropharmacology, Project Office for Neuropsychological Research Center, Fujita Health University, Toyoake, Aichi, Japan
| | - Mutsuki Amano
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Kozo Kaibuchi
- Department of Cell Pharmacology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan.,Research Project for Neural and Tumor Signaling, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake, Aichi, Japan
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13
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Kamikawa Y, Yokota K, Oikawa K, Sato F, Muragaki Y. Suppression of MKL1 promotes adipocytic differentiation and reduces the proliferation of myxoid liposarcoma cells. Oncol Lett 2020; 20:369. [PMID: 33154767 DOI: 10.3892/ol.2020.12232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 09/23/2020] [Indexed: 11/05/2022] Open
Abstract
Myxoid liposarcoma (MLS) is thought to occur due to defective adipocytic differentiation in mesenchymal stem cells. A promising strategy for MLS treatment is the prevention of sarcomagenesis by promoting the terminal differentiation of MLS cells into adipocytes. Previous studies have reported that the suppression of megakaryoblastic leukemia 1 (MKL1) expression induces adipocytic differentiation in preadipocyte cell lines. The present study aimed to investigate the effects of MKL1 suppression on MLS cells. In the present study, MKL1 knockdown was demonstrated to promote the adipocytic differentiation of an MLS-derived cell line, designated 1955/91, under adipogenic conditions. This suggests that therapeutic targeting of the MKL1-associated molecular pathway has potential as a promising method of MLS treatment. However, the induction of adipogenesis by MKL knockdown was incomplete, and Oil Red O staining indicated that intracellular lipid droplets were only sporadically generated. Conversely, MKL1 knockdown reduced the growth of the MLS cells. As adipocytic differentiation in vitro requires cellular confluence, the decreased growth rate of the MLS cells following MKL1 knockdown could be attributed to the incomplete induction of adipogenesis. Translocated in liposarcoma-CCAAT/enhancer-binding protein homologous protein (TLS-CHOP) is an MLS-specific oncoprotein that is thought to play key roles in sarcomagenesis and the suppression of adipocytic differentiation. However, the results of western blotting analyses suggest that TLS-CHOP has limited effects on MKL1 expression in MLS cells and that MKL1 knockdown hardly affects TLS-CHOP expression. Thus, it is postulated that the inhibitory effect of TLS-CHOP on adipogenesis is not associated with MKL1 expression. However, MKL1 and the molecular pathway involving MKL1 appear to be attractive targets for the differentiation therapy of MLS.
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Affiliation(s)
- Yohei Kamikawa
- Department of Pathology, Wakayama Medical University, Wakayama 641-8509, Japan
| | - Kento Yokota
- Department of Pathology, Wakayama Medical University, Wakayama 641-8509, Japan
| | - Kosuke Oikawa
- Department of Pathology, Wakayama Medical University, Wakayama 641-8509, Japan
| | - Fuyuki Sato
- Department of Pathology, Wakayama Medical University, Wakayama 641-8509, Japan
| | - Yasuteru Muragaki
- Department of Pathology, Wakayama Medical University, Wakayama 641-8509, Japan
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14
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Ishibashi Y, Shoji S, Ihara D, Kubo Y, Tanaka T, Tanabe H, Hakamata T, Miyata T, Satou N, Sakagami H, Mizuguchi M, Kikuchi K, Fukuchi M, Tsuda M, Takasaki I, Tabuchi A. Expression of SOLOIST/MRTFB i4, a novel neuronal isoform of the mouse serum response factor coactivator myocardin-related transcription factor-B, negatively regulates dendritic complexity in cortical neurons. J Neurochem 2020; 159:762-777. [PMID: 32639614 DOI: 10.1111/jnc.15122] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 10/11/2019] [Accepted: 07/02/2020] [Indexed: 12/12/2022]
Abstract
Megakaryoblastic leukemia 2 (MKL2)/myocardin-related transcription factor-B (MRTFB), a serum response factor (SRF) coactivator, is an important regulator of gene expression and neuronal morphology. Here, we show that different mouse MRTFB splice isoforms, including a novel fourth MRTFB isoform named spliced neuronal long isoform of SRF transcriptional coactivator (SOLOIST)/MRTFB isoform 4 (MRTFB i4), play distinct roles in this process. SOLOIST/MRTFB i4 has a short exon that encodes 21 amino acid residues ahead of the first RPXXXEL (RPEL) motif in MRTFB isoform 3. Quantitative PCR revealed that SOLOIST/MRTFB i4 and isoform 1 were enriched in the forebrain and neurons, and up-regulated during brain development. Conversely, isoform 3 was detected in various tissues, including both neurons and astrocytes, and was down-regulated in the developing brain. Reporter assays supported the SRF-coactivator function of SOLOIST/MRTFB i4 as well as isoform 1. Acute expression of MRTFB isoform 1, but not isoform 3 or SOLOIST/MRTFB i4, in neuronal cells within 24 hr drastically increased endogenous immediate early gene [c-fos, egr1, and activity-regulated cytoskeleton-associated protein] expression, but not endogenous actinin α1, β-actin, gelsolin, or srf gene expression measured by qPCR. Over-expression of SOLOIST/MRTFB i4 reduced the dendritic complexity of cortical neurons, whereas over-expression of isoform 1 increased this complexity. Co-expression of isoform 1 and SOLOIST/MRTFB i4 in cortical neurons revealed that isoform 1 competitively counteracted down-regulation by SOLOIST/MRTFB i4. Our findings indicate that MRTFB isoforms have unique expression patterns and differential effects on gene expression and dendritic complexity, which contribute to shaping neuronal circuits, at least in part.
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Affiliation(s)
- Yuta Ishibashi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Shizuku Shoji
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Daisuke Ihara
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan.,Laboratory of Molecular Neurobiology, Faculty of Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Yukimi Kubo
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Takuro Tanaka
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Hiroki Tanabe
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Tomoyuki Hakamata
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Tomoaki Miyata
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Natsumi Satou
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Mineyuki Mizuguchi
- Laboratory of Structural Biology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Keietsu Kikuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Mamoru Fukuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan.,Present affiliation: Laboratory of Molecular Neuroscience, Faculty of Pharmacy, Takasaki University of Health and Welfare, Takasaki, Gunma, Japan
| | - Masaaki Tsuda
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Ichiro Takasaki
- Department of Pharmacology, Graduate School of Science and Engineering, Graduate School of Innovative Life Sciences, University of Toyama, Toyama, Japan
| | - Akiko Tabuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine & Pharmaceutical Sciences, University of Toyama, Toyama, Japan.,Laboratory of Molecular Neurobiology, Faculty of Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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15
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Phosphorylation of Npas4 by MAPK Regulates Reward-Related Gene Expression and Behaviors. Cell Rep 2019; 29:3235-3252.e9. [DOI: 10.1016/j.celrep.2019.10.116] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/02/2019] [Accepted: 10/28/2019] [Indexed: 02/06/2023] Open
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16
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Gerosa L, Grillo B, Forastieri C, Longaretti A, Toffolo E, Mallei A, Bassani S, Popoli M, Battaglioli E, Rusconi F. SRF and SRFΔ5 Splicing Isoform Recruit Corepressor LSD1/KDM1A Modifying Structural Neuroplasticity and Environmental Stress Response. Mol Neurobiol 2019; 57:393-407. [DOI: 10.1007/s12035-019-01720-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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17
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Montel L, Sotiropoulos A, Hénon S. The nature and intensity of mechanical stimulation drive different dynamics of MRTF-A nuclear redistribution after actin remodeling in myoblasts. PLoS One 2019; 14:e0214385. [PMID: 30921405 PMCID: PMC6438519 DOI: 10.1371/journal.pone.0214385] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 03/12/2019] [Indexed: 01/14/2023] Open
Abstract
Serum response factor and its cofactor myocardin-related transcription factor (MRTF) are key elements of muscle-mass adaptation to workload. The transcription of target genes is activated when MRTF is present in the nucleus. The localization of MRTF is controlled by its binding to G-actin. Thus, the pathway can be mechanically activated through the mechanosensitivity of the actin cytoskeleton. The pathway has been widely investigated from a biochemical point of view, but its mechanical activation and the timescales involved are poorly understood. Here, we applied local and global mechanical cues to myoblasts through two custom-built set-ups, magnetic tweezers and stretchable substrates. Both induced nuclear accumulation of MRTF-A. However, the dynamics of the response varied with the nature and level of mechanical stimulation and correlated with the polymerization of different actin sub-structures. Local repeated force induced local actin polymerization and nuclear accumulation of MRTF-A by 30 minutes, whereas a global static strain induced both rapid (minutes) transient nuclear accumulation, associated with the polymerization of an actin cap above the nucleus, and long-term accumulation, with a global increase in polymerized actin. Conversely, high strain induced actin depolymerization at intermediate times, associated with cytoplasmic MRTF accumulation.
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Affiliation(s)
- Lorraine Montel
- Matière et Systèmes Complexes, CNRS UMR 7057, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Athanassia Sotiropoulos
- Institut Cochin, INSERM U1016, CNRS UMR 8104, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sylvie Hénon
- Matière et Systèmes Complexes, CNRS UMR 7057, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
- * E-mail:
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18
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Methylmercury induces the expression of chemokine CCL4 via SRF activation in C17.2 mouse neural stem cells. Sci Rep 2019; 9:4631. [PMID: 30874621 PMCID: PMC6420654 DOI: 10.1038/s41598-019-41127-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Accepted: 02/27/2019] [Indexed: 12/23/2022] Open
Abstract
Methylmercury is an environmental pollutant that causes specific and serious damage to the central nervous system. We have previously shown that C-C motif chemokine ligand 4 (CCL4) protects cultured neural cells from methylmercury toxicity and expression of CCL4 is specifically induced in mouse brain by methylmercury. In this study, we examined the transcriptional regulatory mechanism that induces CCL4 expression by methylmercury using C17.2 mouse neural stem cells. The promoter region of the CCL4 gene was analyzed by a reporter assay, revealing that the region up to 50 bp upstream from the transcription start site was necessary for inducing expression of CCL4 by methylmercury. Nine transcription factors that might bind to this upstream region and be involved in the induction of CCL4 expression by methylmercury were selected, and the induction of CCL4 expression by methylmercury was suppressed by the knockdown of serum response factor (SRF). In addition, the nuclear level of SRF was elevated by methylmercury, and an increase in the amount bound to the CCL4 gene promoter was also observed. Furthermore, we examined the upstream signaling pathway involved in the induction of CCL4 expression by SRF, and confirmed that activation of p38 and ERK, which are part of the MAPK pathway, are involved. These results suggest that methylmercury induces the expression of CCL4 by activating SRF via the p38 and ERK signaling pathway. Our findings are important for elucidating the mechanism involved in the brain-specific induction of CCL4 expression by methylmercury.
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19
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Dai J, Qin L, Chen Y, Wang H, Lin G, Li X, Liao H, Fang H. Matrix stiffness regulates epithelial-mesenchymal transition via cytoskeletal remodeling and MRTF-A translocation in osteosarcoma cells. J Mech Behav Biomed Mater 2018; 90:226-238. [PMID: 30384218 DOI: 10.1016/j.jmbbm.2018.10.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 10/02/2018] [Accepted: 10/03/2018] [Indexed: 12/20/2022]
Abstract
Matrix stiffness is known to alter cellular behaviors in various biological contexts. Previous investigations have shown that epithelial-mesenchymal transition (EMT) promotes the progression and invasion of tumor. Mechanical signaling is identified as a regulator of EMT. However, the molecular mechanisms underlying the influence exerted by matrix stiffness on EMT in osteosarcoma remains largely unknown. Using polyacrylamide hydrogel model, we investigate the effects of matrix stiffness on EMT and migration in osteosarcoma. Our data indicates that high matrix stiffness regulates cell morphology and promotes EMT and migration in osteosarcoma MG63 cell line in vitro. Notably, matrix stiffness promotes polymerization of actin and nuclear accumulation of myocardin-related transcription factor A (MRTF-A). Furthermore, inhibiting MRTF-A by CCG 203971 significantly reduces EMT and migration on rigid gels. These data suggest that matrix stiffness of the tumor microenvironment actively regulate osteosarcoma EMT and migration through cytoskeletal remodeling and translocation of MRTF-A, which may contribute to cancer progression.
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Affiliation(s)
- Jun Dai
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Qiaokou District, Wuhan 430030, China
| | - Liang Qin
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Qiaokou District, Wuhan 430030, China
| | - Yan Chen
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Qiaokou District, Wuhan 430030, China
| | - Huan Wang
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Qiaokou District, Wuhan 430030, China
| | - Guanlin Lin
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Qiaokou District, Wuhan 430030, China
| | - Xiao Li
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Qiaokou District, Wuhan 430030, China
| | - Hui Liao
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Qiaokou District, Wuhan 430030, China.
| | - Huang Fang
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Qiaokou District, Wuhan 430030, China.
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20
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Kikuchi K, Ihara D, Fukuchi M, Tanabe H, Ishibashi Y, Tsujii J, Tsuda M, Kaneda M, Sakagami H, Okuno H, Bito H, Yamazaki Y, Ishikawa M, Tabuchi A. Involvement of SRF coactivator MKL2 in BDNF-mediated activation of the synaptic activity-responsive element in the Arc gene. J Neurochem 2018; 148:204-218. [PMID: 30244496 DOI: 10.1111/jnc.14596] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 09/12/2018] [Accepted: 09/18/2018] [Indexed: 12/31/2022]
Abstract
The expression of immediate early genes (IEGs) is thought to be an essential molecular basis of neuronal plasticity for higher brain function. Many IEGs contain serum response element in their transcriptional regulatory regions and their expression is controlled by serum response factor (SRF). SRF is known to play a role in concert with transcriptional cofactors. However, little is known about how SRF cofactors regulate IEG expression during the process of neuronal plasticity. We hypothesized that one of the SRF-regulated neuronal IEGs, activity-regulated cytoskeleton-associated protein (Arc; also termed Arg3.1), is regulated by an SRF coactivator, megakaryoblastic leukemia (MKL). To test this hypothesis, we initially investigated which binding site of the transcription factor or SRF cofactor contributes to brain-derived neurotrophic factor (BDNF)-induced Arc gene transcription in cultured cortical neurons using transfection and reporter assays. We found that BDNF caused robust induction of Arc gene transcription through a cAMP response element, binding site of myocyte enhancer factor 2, and binding site of SRF in an Arc enhancer, the synaptic activity-responsive element (SARE). Regardless of the requirement for the SRF-binding site, the binding site of a ternary complex factor, another SRF cofactor, did not affect BDNF-mediated Arc gene transcription. In contrast, chromatin immunoprecipitation revealed occupation of MKL at the SARE. Furthermore, knockdown of MKL2, but not MKL1, significantly decreased BDNF-mediated activation of the SARE. Taken together, these findings suggest a novel mechanism by which MKL2 controls the Arc SARE in response to BDNF stimulation.
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Affiliation(s)
- Keietsu Kikuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Daisuke Ihara
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Mamoru Fukuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Hiroki Tanabe
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Yuta Ishibashi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Junya Tsujii
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Masaaki Tsuda
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Marisa Kaneda
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Hiroyuki Sakagami
- Department of Anatomy, Kitasato University School of Medicine, Sagamihara, Kanagawa, Japan
| | - Hiroyuki Okuno
- Department of Biochemistry and Molecular Biology, Graduate School of Medical and Dental Sciences, Kagoshima University, Sakuragaoka, Kagoshima, Japan
| | - Haruhiko Bito
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yuya Yamazaki
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Mitsuru Ishikawa
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Akiko Tabuchi
- Laboratory of Molecular Neurobiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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21
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Synaptic localisation of SRF coactivators, MKL1 and MKL2, and their role in dendritic spine morphology. Sci Rep 2018; 8:727. [PMID: 29335431 PMCID: PMC5768758 DOI: 10.1038/s41598-017-18905-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 12/15/2017] [Indexed: 01/01/2023] Open
Abstract
The megakaryoblastic leukaemia (MKL) family are serum response factor (SRF) coactivators, which are highly expressed in the brain. Accordingly, MKL plays important roles in dendritic morphology, neuronal migration, and brain development. Further, nucleotide substitutions in the MKL1 and MKL2 genes are found in patients with schizophrenia and autism spectrum disorder, respectively. Thus, studies on the precise synaptic localisation and function of MKL in neurons are warranted. In this study, we generated and tested new antibodies that specifically recognise endogenously expressed MKL1 and MKL2 proteins in neurons. Using these reagents, we biochemically and immunocytochemically show that MKL1 and MKL2 are localised at synapses. Furthermore, shRNA experiments revealed that postsynaptic deletion of MKL1 or MKL2 reduced the percentage of mushroom- or stubby-type spines in cultured neurons. Taken together, our findings suggest that MKL1 and MKL2 are present at synapses and involved in dendritic spine maturation. This study may, at least in part, contribute to better understanding of the molecular mechanisms underlying MKL-mediated synaptic plasticity and neurological disorders.
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22
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Wang D, Cheng Z, Zhao X, Li Z, Wang J, Dong A, Zhou Z, Zhang F. Association between MKL1 rs6001946 and schizophrenia in a Han Chinese population. Neurosci Lett 2016; 631:36-39. [PMID: 27507698 DOI: 10.1016/j.neulet.2016.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 07/16/2016] [Accepted: 08/05/2016] [Indexed: 10/21/2022]
Abstract
Megakaryoblastic leukemia 1 (MKL1) is highly expressed in the nervous system and plays a potentially principal role in neuronal migration and morphology. A recent study showed that some genetic loci within the MKL1 gene, especially single nucleotide polymorphism (SNP) rs6001946, may increase schizophrenia susceptibility. Here, we sought to determine whether the polymorphism rs6001946 was associated with schizophrenia in a Han Chinese population using the ligase detection reaction-polymerase chain reaction method to genotype SNP rs6001946 in the MKL1 gene. We observed that there was a marginally significant association between SNP rs6001946 and the risk of schizophrenia (P=0.077). Our results indicated that SNP rs6001946 of the MKL1 gene is likely a risk factor for schizophrenia, but the role of SNP rs6001946 in the development of schizophrenia in Han Chinese should be interpreted cautiously. Further studies with larger sample sizes are needed to determine the involvement of the MKL1 polymorphism in schizophrenia susceptibility.
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Affiliation(s)
- Dong Wang
- Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, Jiangsu Province, China
| | - Zaohuo Cheng
- Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, Jiangsu Province, China
| | - Xingfu Zhao
- Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, Jiangsu Province, China
| | - Zongchang Li
- Institute of Mental Health of the second Xiangya hospital, National Laboratory for Psychiatry Disease Diagnosis and Treatment, Key Laboratory of Psychiatry and Mental Health of Hunan Province, The Central South University, Changsha, China
| | - Jun Wang
- Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, Jiangsu Province, China
| | - Aiguo Dong
- Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, Jiangsu Province, China
| | - Zhenhe Zhou
- Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, Jiangsu Province, China
| | - Fuquan Zhang
- Wuxi Mental Health Center, Nanjing Medical University, Wuxi, 214151, Jiangsu Province, China.
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Cenik BK, Liu N, Chen B, Bezprozvannaya S, Olson EN, Bassel-Duby R. Myocardin-related transcription factors are required for skeletal muscle development. Development 2016; 143:2853-61. [PMID: 27385017 PMCID: PMC5004908 DOI: 10.1242/dev.135855] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 06/17/2016] [Indexed: 12/24/2022]
Abstract
Myocardin-related transcription factors (MRTFs) play a central role in the regulation of actin expression and cytoskeletal dynamics. Stimuli that promote actin polymerization allow for shuttling of MRTFs to the nucleus where they activate serum response factor (SRF), a regulator of actin and other cytoskeletal protein genes. SRF is an essential regulator of skeletal muscle differentiation and numerous components of the muscle sarcomere, but the potential involvement of MRTFs in skeletal muscle development has not been examined. We explored the role of MRTFs in muscle development in vivo by generating mutant mice harboring a skeletal muscle-specific deletion of MRTF-B and a global deletion of MRTF-A. These double knockout (dKO) mice were able to form sarcomeres during embryogenesis. However, the sarcomeres were abnormally small and disorganized, causing skeletal muscle hypoplasia and perinatal lethality. Transcriptome analysis demonstrated dramatic dysregulation of actin genes in MRTF dKO mice, highlighting the importance of MRTFs in actin cycling and myofibrillogenesis. MRTFs were also shown to be necessary for the survival of skeletal myoblasts and for the efficient formation of intact myotubes. Our findings reveal a central role for MRTFs in sarcomere formation during skeletal muscle development and point to the potential involvement of these transcriptional co-activators in skeletal myopathies.
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Affiliation(s)
- Bercin K Cenik
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Ning Liu
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Beibei Chen
- Clinical Sciences, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Svetlana Bezprozvannaya
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Eric N Olson
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
| | - Rhonda Bassel-Duby
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA The Hamon Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9148, USA
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Zhang Y, Pan HY, Hu XM, Cao XL, Wang J, Min ZL, Xu SQ, Xiao W, Yuan Q, Li N, Cheng J, Zhao SQ, Hong X. The role of myocardin-related transcription factor-A in Aβ25-35 induced neuron apoptosis and synapse injury. Brain Res 2016; 1648:27-34. [PMID: 27387387 DOI: 10.1016/j.brainres.2016.07.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 06/19/2016] [Accepted: 07/04/2016] [Indexed: 11/18/2022]
Abstract
Myocardin-related transcription factor-A (MRTF-A) highly expressed in brain has been demonstrated to promote neuronal survival via regulating the transcription of related target genes as a powerful co-activator of serum response factor (SRF). However, the role of MRTF-A in Alzheimer's disease (AD) is still unclear. Here, we showed that MRTF-A was significantly downregulated in cortex of the Aβ25-35-induced AD rats, which played a key role in Aβ25-35 induced cerebral neuronal degeneration in vitro. Bilateral intracerebroventricular injection of Aβ25-35 caused significantly MRTF-A expression decline in cortex of rats, along with significant neuron apoptosis and plasticity damage. In vitro, transfection of MRTF-A into primary cultured cortical neurons prevented Aβ25-35 induced neuronal apoptosis and synapses injury. And luciferase reporter assay determined that MRTF-A could bind to and enhance the transactivity of the Mcl-1 (Myeloid cell leukemia-1) and Arc (activity-regulated cytoskeletal-associated protein) promoters by activating the key CArG box element. These data demonstrated that the decreasing of endogenous MRTF-A expression might contribute to the development of AD, whereas the upregulation MRTF-A in neurons could effectively reduce Aβ25-35 induced synapse injury and cell apoptosis. And the underlying mechanism might be partially due to MRTF-A-mediated the transcription and expression of Mcl-1 and Arc by triggering the CArG box.
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Affiliation(s)
- Ying Zhang
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Hong-Yan Pan
- Tianyou Hospital Affiliated to Wuhan University of Science and Technology, Wuhan 430064, PR China
| | - Xia-Min Hu
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China.
| | - Xiao-Lu Cao
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Jun Wang
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Zhen-Li Min
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Shi-Qiang Xu
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Wan Xiao
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Qiong Yuan
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Na Li
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Jing Cheng
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Shu-Qi Zhao
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
| | - Xing Hong
- Department of Pharmacology, Medical College of Wuhan University of Science and Technology, Wuhan 430080, PR China
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Kuzniewska B, Nader K, Dabrowski M, Kaczmarek L, Kalita K. Adult Deletion of SRF Increases Epileptogenesis and Decreases Activity-Induced Gene Expression. Mol Neurobiol 2016; 53:1478-1493. [PMID: 25636686 PMCID: PMC4789231 DOI: 10.1007/s12035-014-9089-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 12/29/2014] [Indexed: 11/27/2022]
Abstract
Although the transcription factor serum response factor (SRF) has been suggested to play a role in activity-dependent gene expression and mediate plasticity-associated structural changes in the hippocampus, no unequivocal evidence has been provided for its role in brain pathology, such as epilepsy. A genome-wide program of activity-induced genes that are regulated by SRF also remains unknown. In the present study, we show that the inducible and conditional deletion of SRF in the adult mouse hippocampus increases the epileptic phenotype in the kainic acid model of epilepsy, reflected by more severe and frequent seizures. Moreover, we observe a robust decrease in activity-induced gene transcription in SRF knockout mice. We characterize the genetic program controlled by SRF in neurons and using functional annotation, we find that SRF target genes are associated with synaptic plasticity and epilepsy. Several of these SRF targets function as regulators of inhibitory or excitatory balance and the structural plasticity of neurons. Interestingly, mutations in those SRF targets have found to be associated with such human neuropsychiatric disorders, as autism and intellectual disability. We also identify novel direct SRF targets in hippocampus: Npas4, Gadd45g, and Zfp36. Altogether, our data indicate that proteins that are highly upregulated by neuronal stimulation, identified in the present study as SRF targets, may function as endogenous protectors against overactivation. Thus, the lack of these effector proteins in SRF knockout animals may lead to uncontrolled excitation and eventually epilepsy.
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Affiliation(s)
- Bozena Kuzniewska
- Laboratory of Neurobiology, Nencki Institute, 3 Pasteur Street, Warsaw, Poland
| | - Karolina Nader
- Laboratory of Neurobiology, Nencki Institute, 3 Pasteur Street, Warsaw, Poland
| | - Michal Dabrowski
- Laboratory of Bioinformatics, Neurobiology Center, Nencki Institute, 3 Pasteur Street, Warsaw, Poland
| | - Leszek Kaczmarek
- Laboratory of Neurobiology, Nencki Institute, 3 Pasteur Street, Warsaw, Poland
| | - Katarzyna Kalita
- Laboratory of Neurobiology, Nencki Institute, 3 Pasteur Street, Warsaw, Poland.
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Meyer zu Reckendorf C, Anastasiadou S, Bachhuber F, Franz-Wachtel M, Macek B, Knöll B. Proteomic analysis of SRF associated transcription complexes identified TFII-I as modulator of SRF function in neurons. Eur J Cell Biol 2016; 95:42-56. [DOI: 10.1016/j.ejcb.2015.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 10/30/2015] [Accepted: 11/05/2015] [Indexed: 11/25/2022] Open
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Scandaglia M, Benito E, Morenilla-Palao C, Fiorenza A, Del Blanco B, Coca Y, Herrera E, Barco A. Fine-tuned SRF activity controls asymmetrical neuronal outgrowth: implications for cortical migration, neural tissue lamination and circuit assembly. Sci Rep 2015; 5:17470. [PMID: 26638868 PMCID: PMC4671020 DOI: 10.1038/srep17470] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/29/2015] [Indexed: 01/09/2023] Open
Abstract
The stimulus-regulated transcription factor Serum Response Factor (SRF) plays an important role in diverse neurodevelopmental processes related to structural plasticity and motile functions, although its precise mechanism of action has not yet been established. To further define the role of SRF in neural development and distinguish between cell-autonomous and non cell-autonomous effects, we bidirectionally manipulated SRF activity through gene transduction assays that allow the visualization of individual neurons and their comparison with neighboring control cells. In vitro assays showed that SRF promotes survival and filopodia formation and is required for normal asymmetric neurite outgrowth, indicating that its activation favors dendrite enlargement versus branching. In turn, in vivo experiments demonstrated that SRF-dependent regulation of neuronal morphology has important consequences in the developing cortex and retina, affecting neuronal migration, dendritic and axonal arborization and cell positioning in these laminated tissues. Overall, our results show that the controlled and timely activation of SRF is essential for the coordinated growth of neuronal processes, suggesting that this event regulates the switch between neuronal growth and branching during developmental processes.
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Affiliation(s)
- Marilyn Scandaglia
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant. 03550. Alicante, Spain
| | - Eva Benito
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant. 03550. Alicante, Spain
| | - Cruz Morenilla-Palao
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant. 03550. Alicante, Spain
| | - Anna Fiorenza
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant. 03550. Alicante, Spain
| | - Beatriz Del Blanco
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant. 03550. Alicante, Spain
| | - Yaiza Coca
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant. 03550. Alicante, Spain
| | - Eloísa Herrera
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant. 03550. Alicante, Spain
| | - Angel Barco
- Instituto de Neurociencias (Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas). Av. Santiago Ramón y Cajal s/n. Sant Joan d'Alacant. 03550. Alicante, Spain
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28
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Immunodeficiency and severe susceptibility to bacterial infection associated with a loss-of-function homozygous mutation of MKL1. Blood 2015. [PMID: 26224645 DOI: 10.1182/blood-2014-12-611012] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Megakaryoblastic leukemia 1 (MKL1), also known as MAL or myocardin-related transcription factor A (MRTF-A), is a coactivator of serum response factor, which regulates transcription of actin and actin cytoskeleton-related genes. MKL1 is known to be important for megakaryocyte differentiation and function in mice, but its role in immune cells is unexplored. Here we report a patient with a homozygous nonsense mutation in the MKL1 gene resulting in immunodeficiency characterized predominantly by susceptibility to severe bacterial infection. We show that loss of MKL1 protein expression causes a dramatic loss of filamentous actin (F-actin) content in lymphoid and myeloid lineage immune cells and widespread cytoskeletal dysfunction. MKL1-deficient neutrophils displayed reduced phagocytosis and almost complete abrogation of migration in vitro. Similarly, primary dendritic cells were unable to spread normally or to form podosomes. Silencing of MKL1 in myeloid cell lines revealed that F-actin assembly was abrogated through reduction of globular actin (G-actin) levels and disturbed expression of multiple actin-regulating genes. Impaired migration of these cells was associated with failure of uropod retraction likely due to altered contractility and adhesion, evidenced by reduced expression of the myosin light chain 9 (MYL9) component of myosin II complex and overexpression of CD11b integrin. Together, our results show that MKL1 is a nonredundant regulator of cytoskeleton-associated functions in immune cells and fibroblasts and that its depletion underlies a novel human primary immunodeficiency.
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Luo XJ, Huang L, van den Oord EJ, Aberg KA, Gan L, Zhao Z, Yao YG. Common variants in the MKL1 gene confer risk of schizophrenia. Schizophr Bull 2015; 41:715-27. [PMID: 25380769 PMCID: PMC4393692 DOI: 10.1093/schbul/sbu156] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Genome-wide association studies (GWAS) of schizophrenia have identified multiple risk variants with robust association signals for schizophrenia. However, these variants could explain only a small proportion of schizophrenia heritability. Furthermore, the effect size of these risk variants is relatively small (eg, most of them had an OR less than 1.2), suggesting that additional risk variants may be detected when increasing sample size in analysis. Here, we report the identification of a genome-wide significant schizophrenia risk locus at 22q13.1 by combining 2 large-scale schizophrenia cohort studies. Our meta-analysis revealed that 7 single nucleotide polymorphism (SNPs) on chromosome 22q13.1 reached the genome-wide significance level (P < 5.0×10(-8)) in the combined samples (a total of 38441 individuals). Among them, SNP rs6001946 had the most significant association with schizophrenia (P = 2.04×10(-8)). Interestingly, all 7 SNPs are in high linkage disequilibrium and located in the MKL1 gene. Expression analysis showed that MKL1 is highly expressed in human and mouse brains. We further investigated functional links between MKL1 and proteins encoded by other schizophrenia susceptibility genes in the whole human protein interaction network. We found that MKL1 physically interacts with GSK3B, a protein encoded by a well-characterized schizophrenia susceptibility gene. Collectively, our results revealed that genetic variants in MKL1 might confer risk to schizophrenia. Further investigation of the roles of MKL1 in the pathogenesis of schizophrenia is warranted.
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Affiliation(s)
- Xiong-jian Luo
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, China;,*To whom correspondence should be addressed; Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, China; tel: 86-871-65180085, fax: 86-871-65180085, e-mail:
| | - Liang Huang
- First Affiliated Hospital of Gannan Medical University, Ganzhou, Jiangxi 341000, China
| | - Edwin J. van den Oord
- Center for Biomarker Research and Personalized Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Karolina A. Aberg
- Center for Biomarker Research and Personalized Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Lin Gan
- Flaum Eye Institute and Department of Ophthalmology, University of Rochester, Rochester, NY 14642, USA
| | - Zhongming Zhao
- Departments of Biomedical Informatics and Psychiatry, Vanderbilt University School of Medicine, Nashville, TN
| | - Yong-Gang Yao
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Kunming, Yunnan, China
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Neuromolecular responses to social challenge: common mechanisms across mouse, stickleback fish, and honey bee. Proc Natl Acad Sci U S A 2014; 111:17929-34. [PMID: 25453090 DOI: 10.1073/pnas.1420369111] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Certain complex phenotypes appear repeatedly across diverse species due to processes of evolutionary conservation and convergence. In some contexts like developmental body patterning, there is increased appreciation that common molecular mechanisms underlie common phenotypes; these molecular mechanisms include highly conserved genes and networks that may be modified by lineage-specific mutations. However, the existence of deeply conserved mechanisms for social behaviors has not yet been demonstrated. We used a comparative genomics approach to determine whether shared neuromolecular mechanisms could underlie behavioral response to territory intrusion across species spanning a broad phylogenetic range: house mouse (Mus musculus), stickleback fish (Gasterosteus aculeatus), and honey bee (Apis mellifera). Territory intrusion modulated similar brain functional processes in each species, including those associated with hormone-mediated signal transduction and neurodevelopment. Changes in chromosome organization and energy metabolism appear to be core, conserved processes involved in the response to territory intrusion. We also found that several homologous transcription factors that are typically associated with neural development were modulated across all three species, suggesting that shared neuronal effects may involve transcriptional cascades of evolutionarily conserved genes. Furthermore, immunohistochemical analyses of a subset of these transcription factors in mouse again implicated modulation of energy metabolism in the behavioral response. These results provide support for conserved genetic "toolkits" that are used in independent evolutions of the response to social challenge in diverse taxa.
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Nonaka M, Kim R, Sharry S, Matsushima A, Takemoto-Kimura S, Bito H. Towards a better understanding of cognitive behaviors regulated by gene expression downstream of activity-dependent transcription factors. Neurobiol Learn Mem 2014; 115:21-9. [PMID: 25173698 DOI: 10.1016/j.nlm.2014.08.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 08/18/2014] [Accepted: 08/20/2014] [Indexed: 12/12/2022]
Abstract
In the field of molecular and cellular neuroscience, it is not a trivial task to see the forest for the trees, where numerous, and seemingly independent, molecules often work in concert to control critical steps of synaptic plasticity and signalling. Here, we will first summarize our current knowledge on essential activity-dependent transcription factors (TFs) such as CREB, MEF2, Npas4 and SRF, then examine how various transcription cofactors (TcoFs) also contribute to defining the transcriptional outputs during learning and memory. This review finally attempts a provisory synthesis that sheds new light on some of the emerging principles of neuronal circuit dynamics driven by activity-regulated gene transcription to help better understand the intricate relationship between activity-dependent gene expression and cognitive behavior.
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Affiliation(s)
- Mio Nonaka
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; Centre for Cognitive and Neural Systems, University of Edinburgh, 1 George Square, Edinburgh EH8 9JZ, United Kingdom
| | - Ryang Kim
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; CREST-Japan Science and Technology Agency, Tokyo 102-0076, Japan
| | - Stuart Sharry
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Ayano Matsushima
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; CREST-Japan Science and Technology Agency, Tokyo 102-0076, Japan
| | - Sayaka Takemoto-Kimura
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Haruhiko Bito
- Department of Neurochemistry, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan; CREST-Japan Science and Technology Agency, Tokyo 102-0076, Japan.
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Transient α-helices in the disordered RPEL motifs of the serum response factor coactivator MKL1. Sci Rep 2014; 4:5224. [PMID: 24909411 PMCID: PMC4048911 DOI: 10.1038/srep05224] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 05/21/2014] [Indexed: 12/17/2022] Open
Abstract
The megakaryoblastic leukemia 1 (MKL1) protein functions as a transcriptional coactivator of the serum response factor. MKL1 has three RPEL motifs (RPEL1, RPEL2, and RPEL3) in its N-terminal region. MKL1 binds to monomeric G-actin through RPEL motifs, and the dissociation of MKL1 from G-actin promotes the translocation of MKL1 to the nucleus. Although structural data are available for RPEL motifs of MKL1 in complex with G-actin, the structural characteristics of RPEL motifs in the free state have been poorly defined. Here we characterized the structures of free RPEL motifs using NMR and CD spectroscopy. NMR and CD measurements showed that free RPEL motifs are largely unstructured in solution. However, NMR analysis identified transient α-helices in the regions where helices α1 and α2 are induced upon binding to G-actin. Proline mutagenesis showed that the transient α-helices are locally formed without helix-helix interactions. The helix content is higher in the order of RPEL1, RPEL2, and RPEL3. The amount of preformed structure may correlate with the binding affinity between the intrinsically disordered protein and its target molecule.
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Lewis TC, Prywes R. Serum regulation of Id1 expression by a BMP pathway and BMP responsive element. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:1147-59. [PMID: 23948603 DOI: 10.1016/j.bbagrm.2013.08.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 08/02/2013] [Accepted: 08/05/2013] [Indexed: 02/01/2023]
Abstract
Immediate early genes (IEGs) are expressed upon re-entry of quiescent cells into the cell cycle following serum stimulation. These genes are involved in growth control and differentiation and hence their expression is tightly controlled. Many IEGs are regulated through Serum Response Elements (SREs) in their promoters, which bind Serum Response Factor (SRF). However, many other IEGs do not have SREs in their promoters and their serum regulation is poorly understood. We have identified SRF-independent IEGs in SRF-depleted fibroblasts. One of these, Id1, was examined more closely. We mapped a serum responsive element in the Id1 promoter and find that it is identical to a BMP responsive element (BRE). The Id1 BRE is necessary and sufficient for the serum regulation of Id1. Inhibition of the BMP pathway by siRNA depletion of Smad 4, treatment with the BMP antagonist noggin, or the BMP receptor inhibitor dorsomorphin blocked serum induction of Id1. Further, BMP2 is sufficient to induce Id1 expression. Given reports that SRC inhibitors can block Id1 expression, we tested the SRC inhibitor, AZD0530, and found that it inhibits the serum activation of Id1. Surprisingly, this inhibition is independent of SRC or its family members. Rather, we show that AZD0530 directly inhibits the BMP type I receptors. Serum induction of the Id1 related gene Id3 also required the BMP pathway. Given these and other findings we conclude that the Id family of IEGs is regulated by BMPs in serum through similar BREs. This represents a second pathway for serum regulation of IEGs.
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Affiliation(s)
- Thera C Lewis
- Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
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Myocardin-related transcription factor-A is a key regulator in retinoic acid-induced neural-like differentiation of adult bone marrow-derived mesenchymal stem cells. Gene 2013; 523:178-86. [DOI: 10.1016/j.gene.2013.03.043] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Revised: 02/28/2013] [Accepted: 03/12/2013] [Indexed: 01/13/2023]
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Ramos EI, Bien-Willner GA, Li J, Hughes AEO, Giacalone J, Chasnoff S, Kulkarni S, Parmacek M, Cole FS, Druley TE. Genetic variation in MKL2 and decreased downstream PCTAIRE1 expression in extreme, fatal primary human microcephaly. Clin Genet 2013; 85:423-32. [PMID: 23692340 PMCID: PMC3929543 DOI: 10.1111/cge.12197] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 05/16/2013] [Accepted: 05/16/2013] [Indexed: 11/26/2022]
Abstract
The genetic mechanisms driving normal brain development remain largely unknown. We performed genomic and immunohistochemical characterization of a novel, fatal human phenotype including extreme microcephaly with cerebral growth arrest at 14-18 weeks gestation in three full sisters born to healthy, non-consanguineous parents. Analysis of index cases and parents included familial exome sequencing, karyotyping, and genome-wide single nucleotide polymorphism (SNP) array. From proband, control and unrelated microcephalic fetal cortical tissue, we compared gene expression of RNA and targeted immunohistochemistry. Each daughter was homozygous for a rare, non-synonymous, deleterious variant in the MKL2 gene and heterozygous for a private 185 kb deletion on the paternal allele, upstream and in cis with his MKL2 variant allele, eliminating 24 CArG transcription factor binding sites and MIR4718. MKL1 was underexpressed in probands. Dysfunction of MKL2 and its transcriptional coactivation partner, serum response factor (SRF), was supported by a decrease in gene and protein expression of PCTAIRE1, a downstream target of MKL2:SRF heterodimer transcriptional activation, previously shown to result in severe microcephaly in murine models. While disruption of the MKL2:SRF axis has been associated with severe microcephaly and disordered brain development in multiple model systems, the role of this transcription factor complex has not been previously demonstrated in human brain development.
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Affiliation(s)
- E I Ramos
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO, USA; Department of Pediatrics
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Abstract
Biological cells are well known to respond to a multitude of chemical signals. In the nervous system, chemical signaling has been shown to be crucially involved in development, normal functioning, and disorders of neurons and glial cells. However, there are an increasing number of studies showing that these cells also respond to mechanical cues. Here, we summarize current knowledge about the mechanical properties of nervous tissue and its building blocks, review recent progress in methodology and understanding of cellular mechanosensitivity in the nervous system, and provide an outlook on the implications of neuromechanics for future developments in biomedical engineering to aid overcoming some of the most devastating and currently incurable CNS pathologies such as spinal cord injuries and multiple sclerosis.
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Affiliation(s)
- Kristian Franze
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3DY, UK.
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mTORC2 controls actin polymerization required for consolidation of long-term memory. Nat Neurosci 2013; 16:441-8. [PMID: 23455608 PMCID: PMC3615448 DOI: 10.1038/nn.3351] [Citation(s) in RCA: 222] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 01/29/2013] [Indexed: 02/07/2023]
Abstract
A major goal of biomedical research has been the identification of molecular mechanisms that can enhance memory. Here we report a novel signaling pathway that regulates the conversion from short- to long-term memory. The mTOR complex 2 (mTORC2), which contains the key regulatory protein Rictor (Rapamycin-Insensitive Companion of mTOR), was discovered only recently, and little is known about its physiological role. We show that conditional deletion of rictor in the postnatal murine forebrain greatly reduces mTORC2 activity and selectively impairs both long-term memory (LTM) and the late (but not the early) phase of hippocampal long-term potentiation (LTP). Actin polymerization is reduced in the hippocampus of mTORC2-deficient mice and its restoration rescues both L-LTP and LTM. More importantly, a compound that selectively promotes mTORC2 activity converts early-LTP into late-LTP and enhances LTM. These findings indicate that mTORC2 could be a novel therapeutic target for the treatment of cognitive dysfunction.
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Actin isoforms in neuronal development and function. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 301:157-213. [PMID: 23317819 DOI: 10.1016/b978-0-12-407704-1.00004-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The actin cytoskeleton contributes directly or indirectly to nearly every aspect of neuronal development and function. This diversity of functions is often attributed to actin regulatory proteins, although how the composition of the actin cytoskeleton itself may influence its function is often overlooked. In neurons, the actin cytoskeleton is composed of two distinct isoforms, β- and γ-actin. Functions for β-actin have been investigated in axon guidance, synaptogenesis, and disease. Insight from loss-of-function in vivo studies has also revealed novel roles for β-actin in select brain structures and behaviors. Conversely, very little is known regarding functions of γ-actin in neurons. The dysregulation or mutation of both β- and γ-actin has been implicated in multiple human neurological disorders, however, demonstrating the critical importance of these still poorly understood proteins. This chapter highlights what is currently known regarding potential distinct functions for β- and γ-actin in neurons as well as the significant areas that remain unexplored.
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