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Coudert L, Osseni A, Gangloff YG, Schaeffer L, Leblanc P. The ESCRT-0 subcomplex component Hrs/Hgs is a master regulator of myogenesis via modulation of signaling and degradation pathways. BMC Biol 2021; 19:153. [PMID: 34330273 PMCID: PMC8323235 DOI: 10.1186/s12915-021-01091-4] [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: 02/09/2021] [Accepted: 07/09/2021] [Indexed: 11/30/2022] Open
Abstract
Background Myogenesis is a highly regulated process ending with the formation of myotubes, the precursors of skeletal muscle fibers. Differentiation of myoblasts into myotubes is controlled by myogenic regulatory factors (MRFs) that act as terminal effectors of signaling cascades involved in the temporal and spatial regulation of muscle development. Such signaling cascades converge and are controlled at the level of intracellular trafficking, but the mechanisms by which myogenesis is regulated by the endosomal machinery and trafficking is largely unexplored. The Endosomal Sorting Complex Required for Transport (ESCRT) machinery composed of four complexes ESCRT-0 to ESCRT-III regulates the biogenesis and trafficking of endosomes as well as the associated signaling and degradation pathways. Here, we investigate its role in regulating myogenesis. Results We uncovered a new function of the ESCRT-0 hepatocyte growth factor-regulated tyrosine kinase substrate Hrs/Hgs component in the regulation of myogenesis. Hrs depletion strongly impairs the differentiation of murine and human myoblasts. In the C2C12 murine myogenic cell line, inhibition of differentiation was attributed to impaired MRF in the early steps of differentiation. This alteration is associated with an upregulation of the MEK/ERK signaling pathway and a downregulation of the Akt2 signaling both leading to the inhibition of differentiation. The myogenic repressors FOXO1 as well as GSK3β were also found to be both activated when Hrs was absent. Inhibition of the MEK/ERK pathway or of GSK3β by the U0126 or azakenpaullone compounds respectively significantly restores the impaired differentiation observed in Hrs-depleted cells. In addition, functional autophagy that is required for myogenesis was also found to be strongly inhibited. Conclusions We show for the first time that Hrs/Hgs is a master regulator that modulates myogenesis at different levels through the control of trafficking, signaling, and degradation pathways. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01091-4.
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Affiliation(s)
- L Coudert
- Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon, 8 avenue Rockefeller, 69373, 09, Lyon, Cedex, France
| | - A Osseni
- Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon, 8 avenue Rockefeller, 69373, 09, Lyon, Cedex, France
| | - Y G Gangloff
- Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon, 8 avenue Rockefeller, 69373, 09, Lyon, Cedex, France
| | - L Schaeffer
- Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon, 8 avenue Rockefeller, 69373, 09, Lyon, Cedex, France
| | - P Leblanc
- Institut NeuroMyoGène, CNRS UMR5310, INSERM U1217, Faculté de Médecine Rockefeller, Université Claude Bernard Lyon, 8 avenue Rockefeller, 69373, 09, Lyon, Cedex, France.
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2
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Fernandez GJ, Ferreira JH, Vechetti IJ, de Moraes LN, Cury SS, Freire PP, Gutiérrez J, Ferretti R, Dal-Pai-Silva M, Rogatto SR, Carvalho RF. MicroRNA-mRNA Co-sequencing Identifies Transcriptional and Post-transcriptional Regulatory Networks Underlying Muscle Wasting in Cancer Cachexia. Front Genet 2020; 11:541. [PMID: 32547603 PMCID: PMC7272700 DOI: 10.3389/fgene.2020.00541] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/05/2020] [Indexed: 12/23/2022] Open
Abstract
Cancer cachexia is a metabolic syndrome with alterations in gene regulatory networks that consequently lead to skeletal muscle wasting. Integrating microRNAs-mRNAs omics profiles offers an opportunity to understand transcriptional and post-transcriptional regulatory networks underlying muscle wasting. Here, we used RNA sequencing to simultaneously integrate and explore microRNAs and mRNAs expression profiles in the tibialis anterior (TA) muscles of the Lewis Lung Carcinoma (LLC) model of cancer cachexia. We found 1,008 mRNAs and 18 microRNAs differentially expressed in cachectic mice compared with controls. Although our transcriptomic analysis demonstrated a high heterogeneity in mRNA profiles of cachectic mice, we identified a reduced number of differentially expressed genes that were uniformly regulated within cachectic muscles. This set of uniformly regulated genes is associated with the extracellular matrix (ECM), proteolysis, and inflammatory response. We also used transcriptomic data to perform enrichment analysis of transcriptional factor binding sites in promoter sequences, which revealed activation of the atrophy-related transcription factors NF-κB, Stat3, AP-1, and FoxO. Furthermore, the integration of mRNA and microRNA expression profiles identified post-transcriptional regulation by microRNAs of genes involved in ECM organization, cell migration, transcription factors binding, ion transport, and the FoxO signaling pathway. Our integrative analysis of microRNA-mRNA co-profiles comprehensively characterized regulatory relationships of molecular pathways and revealed microRNAs targeting ECM-associated genes in cancer cachexia.
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Affiliation(s)
- Geysson Javier Fernandez
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Botucatu, Brazil.,Faculty of Medicine, University of Antioquia, Medellín, Colombia
| | - Juarez Henrique Ferreira
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | - Ivan José Vechetti
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | - Leonardo Nazario de Moraes
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | - Sarah Santiloni Cury
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | - Paula Paccielli Freire
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | - Jayson Gutiérrez
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Renato Ferretti
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | - Maeli Dal-Pai-Silva
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
| | - Silvia Regina Rogatto
- Department of Clinical Genetics, University Hospital of Southern Denmark, Vejle, Institute of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Robson Francisco Carvalho
- Department of Structural and Functional Biology, Institute of Biosciences, São Paulo State University, Botucatu, Brazil
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3
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Chen M, Yao YL, Yang Y, Zhu M, Tang Y, Liu S, Li K, Tang Z. Comprehensive Profiles of mRNAs and miRNAs Reveal Molecular Characteristics of Multiple Organ Physiologies and Development in Pigs. Front Genet 2019; 10:756. [PMID: 31552085 PMCID: PMC6737989 DOI: 10.3389/fgene.2019.00756] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/17/2019] [Indexed: 12/13/2022] Open
Abstract
The pig (Sus scrofa) is not only an important livestock animal but also widely used as a biomedical model. However, the understanding of the molecular characteristics of organs and of the developmental skeletal muscle of the pig is severely limited. Here, we performed a comprehensive transcriptome profiling of mRNAs and miRNAs across nine tissues and three skeletal muscle developmental stages in the Guizhou miniature pig. The reproductive organs (ovary and testis) had greater transcriptome complexity and activity than other tissues, and the highest transcriptome similarity was between skeletal muscle and heart (R = 0.79). We identified 1,819 mRNAs and 96 miRNAs to be tissue-specific in nine organs. Testis had the largest number of tissue-specific mRNAs (992) and miRNAs (40). Only 15 genes and two miRNAs were specifically expressed in skeletal muscle and fat, respectively. During postnatal skeletal muscle development, the mRNAs associated with focal adhesion, Notch signaling, protein digestion, and absorption pathways were up-regulated from D0 to D30 and then down-regulated from D30 and D240, while genes with opposing expression patterns were significantly enriched in the oxidative phosphorylation and proteasome pathways. The miRNAs mainly regulated genes associated with insulin, Wnt, fatty acid biosynthesis, Notch, MAPK, TGF-beta, insulin secretion, ECM-receptor interaction, focal adhesion, and calcium signaling pathways. We also identified 37 new miRNA-mRNA interaction pairs involved in skeletal muscle development. Overall, our data not only provide a rich resource for understanding pig organ physiology and development but also aid the study of the molecular functions of mRNA and miRNA in mammals.
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Affiliation(s)
- Muya Chen
- Research Centre for Animal Genome, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.,Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yi Long Yao
- Research Centre for Animal Genome, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.,Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yalan Yang
- Research Centre for Animal Genome, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.,Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Min Zhu
- Research Centre for Animal Genome, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.,Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Yijie Tang
- Research Centre for Animal Genome, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.,Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Siyuan Liu
- Research Centre for Animal Genome, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.,Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China
| | - Kui Li
- Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Zhonglin Tang
- Research Centre for Animal Genome, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.,Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, China.,Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, China
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4
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Blondelle J, Tallapaka K, Seto JT, Ghassemian M, Clark M, Laitila JM, Bournazos A, Singer JD, Lange S. Cullin-3 dependent deregulation of ACTN1 represents a new pathogenic mechanism in nemaline myopathy. JCI Insight 2019; 5:125665. [PMID: 30990797 PMCID: PMC6542616 DOI: 10.1172/jci.insight.125665] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 04/11/2019] [Indexed: 12/11/2022] Open
Abstract
Nemaline myopathy is a congenital neuromuscular disorder characterized by muscle weakness, fiber atrophy and presence of nemaline bodies within myofibers. However, the understanding of underlying pathomechanisms is lacking. Recently, mutations in KBTBD13, KLHL40 and KLHL41, three substrate adaptors for the E3-ubiquitin ligase Cullin-3, have been associated with early-onset nemaline myopathies. We hypothesized that deregulation of Cullin-3 and its muscle protein substrates may be responsible for the disease development. Using Cullin-3 knockout mice, we identified accumulation of non-muscle alpha-Actinins (ACTN1 and ACTN4) in muscles of these mice, which we also observed in KBTBD13 patients. Our data reveal that proper regulation of Cullin-3 activity and ACTN1 levels is essential for normal muscle and neuromuscular junction development. While ACTN1 is naturally downregulated during myogenesis, its overexpression in C2C12 myoblasts triggered defects in fusion, myogenesis and acetylcholine receptor clustering; features that we characterized in Cullin-3 deficient mice. Taken together, our data highlight the importance for Cullin-3 mediated degradation of ACTN1 for muscle development, and indicate a new pathomechanism for the etiology of myopathies seen in Cullin-3 knockout mice and nemaline myopathy patients.
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Affiliation(s)
- Jordan Blondelle
- Division of Cardiology, School of Medicine, UCSD, La Jolla, California, USA
| | - Kavya Tallapaka
- Division of Cardiology, School of Medicine, UCSD, La Jolla, California, USA
| | - Jane T. Seto
- Neuromuscular Research, Murdoch Children’s Research Institute, Royal Children’s Hospital, Parkville, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Majid Ghassemian
- Department of Chemistry and Biochemistry. UCSD, La Jolla, California, USA
| | - Madison Clark
- Division of Cardiology, School of Medicine, UCSD, La Jolla, California, USA
| | - Jenni M. Laitila
- Folkhälsan Research Center and Medicum, University of Helsinki, Helsinki, Finland
| | - Adam Bournazos
- Kids Neuroscience Centre, Kids Research, Children’s Hospital at Westmead, Sydney, New South Wales, Australia
- Discipline of Child and Adolescent Health, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Jeffrey D. Singer
- Department of Biology, Portland State University, Portland, Oregon, USA
| | - Stephan Lange
- Division of Cardiology, School of Medicine, UCSD, La Jolla, California, USA
- Wallenberg Laboratory, Department of Molecular and Clinical Medicine, Institute of Medicine, University of Gothenburg, Gothenburg, Sweden
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5
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Zhu J, Wu G, Ke Z, Cao L, Tang M, Li Z, Li Q, Zhou J, Tan Z, Song L, Li J. Targeting TRIM3 deletion-induced tumor-associated lymphangiogenesis prohibits lymphatic metastasis in esophageal squamous cell carcinoma. Oncogene 2018; 38:2736-2749. [DOI: 10.1038/s41388-018-0621-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Accepted: 11/23/2018] [Indexed: 01/06/2023]
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6
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Zhao X, Khurana S, Charkraborty S, Tian Y, Sedor JR, Bruggman LA, Kao HY. α Actinin 4 (ACTN4) Regulates Glucocorticoid Receptor-mediated Transactivation and Transrepression in Podocytes. J Biol Chem 2016; 292:1637-1647. [PMID: 27998979 DOI: 10.1074/jbc.m116.755546] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 12/19/2016] [Indexed: 12/14/2022] Open
Abstract
Glucocorticoids are a general class of steroids that possess renoprotective activity in glomeruli through their interaction with the glucocorticoid receptor. However, the mechanisms by which glucocorticoids ameliorate proteinuria and glomerular disease are not well understood. In this study, we demonstrated that α actinin 4 (ACTN4), an actin-cross-linking protein known to coordinate cytoskeletal organization, interacts with the glucocorticoid receptor (GR) in the nucleus of human podocytes (HPCs), a key cell type in the glomerulus critical for kidney filtration function. The GR-ACTN4 complex enhances glucocorticoid response element (GRE)-driven reporter activity. Stable knockdown of ACTN4 by shRNA in HPCs significantly reduces dexamethasone-mediated induction of GR target genes and GRE-driven reporter activity without disrupting dexamethasone-induced nuclear translocation of GR. Synonymous mutations or protein expression losses in ACTN4 are associated with kidney diseases, including focal segmental glomerulosclerosis, characterized by proteinuria and podocyte injury. We found that focal segmental glomerulosclerosis-linked ACTN4 mutants lose their ability to bind liganded GR and support GRE-mediated transcriptional activity. Mechanistically, GR and ACTN4 interact in the nucleus of HPCs. Furthermore, disruption of the LXXLL nuclear receptor-interacting motif present in ACTN4 results in reduced GR interaction and dexamethasone-mediated transactivation of a GRE reporter while still maintaining its actin-binding activity. In contrast, an ACTN4 isoform, ACTN4 (Iso), that loses its actin-binding domain is still capable of potentiating a GRE reporter. Dexamethasone induces the recruitment of ACTN4 and GR to putative GREs in dexamethasone-transactivated promoters, SERPINE1, ANGPLT4, CCL20, and SAA1 as well as the NF-κB (p65) binding sites on GR-transrepressed promoters such as IL-1β, IL-6, and IL-8 Taken together, our data establish ACTN4 as a transcriptional co-regulator that modulates both dexamethasone-transactivated and -transrepressed genes in podocytes.
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Affiliation(s)
- Xuan Zhao
- From the Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Simran Khurana
- From the Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Sharmistha Charkraborty
- From the Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Yuqian Tian
- From the Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - John R Sedor
- Rammelkamp Center for Education and Research and Department of Medicine, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Leslie A Bruggman
- Rammelkamp Center for Education and Research and Department of Medicine, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Hung-Ying Kao
- From the Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106; Case Comprehensive Cancer Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106.
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7
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Introducing STRaNDs: shuttling transcriptional regulators that are non-DNA binding. Nat Rev Mol Cell Biol 2016; 17:523-32. [PMID: 27220640 DOI: 10.1038/nrm.2016.41] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Many proteins originally identified as cytoplasmic - including many associated with the cytoskeleton or cell junctions - are increasingly being found in the nucleus, where they have specific functions. Here, we focus on proteins that translocate from the cytoplasm to the nucleus in response to external signals and regulate transcription without binding to DNA directly (for example, through interaction with transcription factors). We propose that proteins with such characteristics are classified as a distinct group of extracellular signalling effectors, and we suggest the term STRaND (shuttling transcriptional regulators and non-DNA binding) to refer to this group. Crucial roles of STRaNDs include linking cell morphology and adhesion with changes in transcriptional programmes in response to signals such as mechanical stresses.
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8
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α-Actinin-4 induces the epithelial-to-mesenchymal transition and tumorigenesis via regulation of Snail expression and β-catenin stabilization in cervical cancer. Oncogene 2016; 35:5893-5904. [PMID: 27065319 DOI: 10.1038/onc.2016.117] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 12/30/2016] [Accepted: 01/08/2016] [Indexed: 02/08/2023]
Abstract
α-Actinin-4 (ACTN4) is frequently amplified and overexpressed in various cancers. Although ACTN4 functions in cancer cell migration and invasion, the roles of ACTN4 during the epithelial-to-mesenchymal transition (EMT) and cervical cancer tumorigenesis are unknown. In this study, we investigated the function of ACTN4 in the progression of cervical cancer and the mechanisms of EMT and tumorigenesis induced by ACTN4. We found that ACTN4 induced EMT by upregulating Snail, which was dependent on the Akt signaling pathway in cervical cancer. ACTN4 induced cell migration and invasion through Snail-mediated matrix metalloproteinase-9 expression. ACTN4 expression level was correlated with stabilization of β-catenin. Accumulatioin of β-catenin owing to ACTN4 induced tumorigenesis via upregulation of genes involved in cell proliferation, including cyclin D1 and c-myc. ACTN4 knockdown reduced cervical cancer cell proliferation and tumor formation in vivo. The expression level of ACTN4 is highly elevated in human cervical tumors, compared with that in normal cervical tissues. ACTN4-overexpressing MDCK cells induced tumor formation and metastatic nodules in nude mice. Our findings indicate that ACTN4 promotes EMT and tumorigenesis by regulating Snail expression and the Akt pathway in cervical cancer. We propose a novel mechanism for EMT and tumorigenesis in cervical cancer.
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9
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Murphy ACH, Young PW. The actinin family of actin cross-linking proteins - a genetic perspective. Cell Biosci 2015; 5:49. [PMID: 26312134 PMCID: PMC4550062 DOI: 10.1186/s13578-015-0029-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 06/22/2015] [Accepted: 06/23/2015] [Indexed: 01/08/2023] Open
Abstract
Actinins are one of the major actin cross-linking proteins found in virtually all cell types and are the ancestral proteins of a larger family that includes spectrin, dystrophin and utrophin. Invertebrates have a single actinin-encoding ACTN gene, while mammals have four. Mutations in all four human genes have now been linked to heritable diseases or traits. ACTN1 mutations cause macrothrombocytopenia, a platelet disorder characterized by excessive bleeding. ACTN2 mutations have been linked to a range of cardiomyopathies, and ACTN4 mutations cause a kidney condition called focal segmental glomerulosclerosis. Intriguingly, approximately 16 % of people worldwide are homozygous for a nonsense mutation in ACTN3 that abolishes actinin-3 protein expression. This ACTN3 null allele has undergone recent positive selection in specific human populations, which may be linked to improved endurance and adaptation to colder climates. In this review we discuss the human genetics of the ACTN gene family, as well as ACTN gene knockout studies in several model organisms. Observations from both of these areas provide insights into the evolution and cellular functions of actinins.
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Affiliation(s)
- Anita C H Murphy
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
| | - Paul W Young
- School of Biochemistry and Cell Biology, University College Cork, Cork, Ireland
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10
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Feng D, DuMontier C, Pollak MR. The role of alpha-actinin-4 in human kidney disease. Cell Biosci 2015; 5:44. [PMID: 26301083 PMCID: PMC4545552 DOI: 10.1186/s13578-015-0036-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/24/2015] [Indexed: 11/19/2022] Open
Abstract
Mutations in the Alpha-actinin-4 gene (ACTN4) cause a rare form of familial focal segmental glomerulosclerosis in humans. Individuals with kidney disease-associated ACTN4 mutations tend to have mild to moderate proteinuria, with many developing decreased kidney function progressing to end stage kidney disease. All of the disease-causing ACTN4 mutations identified to date are located within the actin-binding domain of the encoded protein, increasing its binding affinity to F-actin and leading to abnormal actin rich cellular aggregates. The identification of ACTN4 mutations as a cause of human kidney disease demonstrates a key cellular pathway by which alterations in cytoskeletal behavior can mediate kidney disease. Here we review the studies relevant to ACTN4 and its role in mediating kidney disease.
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Affiliation(s)
- Di Feng
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215 USA
| | - Clark DuMontier
- Department of Medicine, Boston University School of Medicine, Boston, MA 02118 USA
| | - Martin R Pollak
- Division of Nephrology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA 02215 USA
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11
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Zhao X, Hsu KS, Lim JH, Bruggeman LA, Kao HY. α-Actinin 4 potentiates nuclear factor κ-light-chain-enhancer of activated B-cell (NF-κB) activity in podocytes independent of its cytoplasmic actin binding function. J Biol Chem 2014; 290:338-49. [PMID: 25411248 DOI: 10.1074/jbc.m114.597260] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Glomerular podocytes are highly specialized terminally differentiated cells that act as a filtration barrier in the kidney. Mutations in the actin-binding protein, α-actinin 4 (ACTN4), are linked to focal segmental glomerulosclerosis (FSGS), a chronic kidney disease characterized by proteinuria. Aberrant activation of NF-κB pathway in podocytes is implicated in glomerular diseases including proteinuria. We demonstrate here that stable knockdown of ACTN4 in podocytes significantly reduces TNFα-mediated induction of NF-κB target genes, including IL-1β and NPHS1, and activation of an NF-κB-driven reporter without interfering with p65 nuclear translocation. Overexpression of ACTN4 and an actin binding-defective variant increases the reporter activity. In contrast, an FSGS-linked ACTN4 mutant, K255E, which has increased actin binding activity and is predominantly cytoplasmic, fails to potentiate NF-κB activity. Mechanistically, IκBα blocks the association of ACTN4 and p65 in the cytosol. In response to TNFα, both NF-κB subunits p65 and p50 translocate to the nucleus, where they bind and recruit ACTN4 to their targeted promoters, IL-1β and IL-8. Taken together, our data identify ACTN4 as a novel coactivator for NF-κB transcription factors in podocytes. Importantly, this nuclear function of ACTN4 is independent of its actin binding activity in the cytoplasm.
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Affiliation(s)
| | | | | | - Leslie A Bruggeman
- Rammelkamp Center for Education and Research and Department of Medicine, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106
| | - Hung-Ying Kao
- From the Department of Biochemistry, Case Comprehensive Cancer Center, and
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