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Šimon M, Mikec Š, Atanur SS, Konc J, Morton NM, Horvat S, Kunej T. Whole genome sequencing of mouse lines divergently selected for fatness (FLI) and leanness (FHI) revealed several genetic variants as candidates for novel obesity genes. Genes Genomics 2024; 46:557-575. [PMID: 38483771 PMCID: PMC11024027 DOI: 10.1007/s13258-024-01507-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 02/25/2024] [Indexed: 04/18/2024]
Abstract
BACKGROUND Analysing genomes of animal model organisms is widely used for understanding the genetic basis of complex traits and diseases, such as obesity, for which only a few mouse models exist, however, without their lean counterparts. OBJECTIVE To analyse genetic differences in the unique mouse models of polygenic obesity (Fat line) and leanness (Lean line) originating from the same base population and established by divergent selection over more than 60 generations. METHODS Genetic variability was analysed using WGS. Variants were identified with GATK and annotated with Ensembl VEP. g.Profiler, WebGestalt, and KEGG were used for GO and pathway enrichment analysis. miRNA seed regions were obtained with miRPathDB 2.0, LncRRIsearch was used to predict targets of identified lncRNAs, and genes influencing adipose tissue amount were searched using the IMPC database. RESULTS WGS analysis revealed 6.3 million SNPs, 1.3 million were new. Thousands of potentially impactful SNPs were identified, including within 24 genes related to adipose tissue amount. SNP density was highest in pseudogenes and regulatory RNAs. The Lean line carries SNP rs248726381 in the seed region of mmu-miR-3086-3p, which may affect fatty acid metabolism. KEGG analysis showed deleterious missense variants in immune response and diabetes genes, with food perception pathways being most enriched. Gene prioritisation considering SNP GERP scores, variant consequences, and allele comparison with other mouse lines identified seven novel obesity candidate genes: 4930441H08Rik, Aff3, Fam237b, Gm36633, Pced1a, Tecrl, and Zfp536. CONCLUSION WGS revealed many genetic differences between the lines that accumulated over the selection period, including variants with potential negative impacts on gene function. Given the increasing availability of mouse strains and genetic polymorphism catalogues, the study is a valuable resource for researchers to study obesity.
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Affiliation(s)
- Martin Šimon
- Chair of Genetics, Animal Biotechnology and Immunology, Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Domžale, 1230, Slovenia.
| | - Špela Mikec
- Chair of Genetics, Animal Biotechnology and Immunology, Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Domžale, 1230, Slovenia
| | - Santosh S Atanur
- Faculty of Medicine, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, SW7 2AZ, UK
- Centre for Genomic and Experimental Medicine, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Janez Konc
- Laboratory for Molecular Modeling, National Institute of Chemistry, Ljubljana, 1000, Slovenia
| | - Nicholas M Morton
- The Queen's Medical Research Institute, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, EH4 2XU, UK
| | - Simon Horvat
- Chair of Genetics, Animal Biotechnology and Immunology, Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Domžale, 1230, Slovenia
| | - Tanja Kunej
- Chair of Genetics, Animal Biotechnology and Immunology, Department of Animal Science, Biotechnical Faculty, University of Ljubljana, Domžale, 1230, Slovenia.
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2
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Frank S, Gabassi E, Käseberg S, Bertin M, Zografidou L, Pfeiffer D, Brennenstuhl H, Falk S, Karow M, Schweiger S. Absence of the RING domain in MID1 results in patterning defects in the developing human brain. Life Sci Alliance 2024; 7:e202302288. [PMID: 38238086 PMCID: PMC10796562 DOI: 10.26508/lsa.202302288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 12/28/2023] [Accepted: 12/29/2023] [Indexed: 01/22/2024] Open
Abstract
The X-linked form of Opitz BBB/G syndrome (OS) is a monogenic disorder in which symptoms are established early during embryonic development. OS is caused by pathogenic variants in the X-linked gene MID1 Disease-associated variants are distributed across the entire gene locus, except for the N-terminal really interesting new gene (RING) domain that encompasses the E3 ubiquitin ligase activity. By using genome-edited human induced pluripotent stem cell lines, we here show that absence of isoforms containing the RING domain of MID1 causes severe patterning defects in human brain organoids. We observed a prominent neurogenic deficit with a reduction in neural tissue and a concomitant increase in choroid plexus-like structures. Transcriptome analyses revealed a deregulation of patterning pathways very early on, even preceding neural induction. Notably, the observed phenotypes starkly contrast with those observed in MID1 full-knockout organoids, indicating the presence of a distinct mechanism that underlies the patterning defects. The severity and early onset of these phenotypes could potentially account for the absence of patients carrying pathogenic variants in exon 1 of the MID1 gene coding for the N-terminal RING domain.
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Affiliation(s)
- Sarah Frank
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Elisa Gabassi
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Stephan Käseberg
- Institute of Human Genetics, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Marco Bertin
- Institute of Human Genetics, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Lea Zografidou
- Institute of Human Genetics, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | - Daniela Pfeiffer
- Institute of Human Genetics, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
| | | | - Sven Falk
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Marisa Karow
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Susann Schweiger
- Institute of Human Genetics, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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3
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Wang Y. Erdr1 Drives Macrophage Programming via Dynamic Interplay with YAP1 and Mid1. Immunohorizons 2024; 8:198-213. [PMID: 38392560 PMCID: PMC10916360 DOI: 10.4049/immunohorizons.2400004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 02/06/2024] [Indexed: 02/24/2024] Open
Abstract
Erythroid differentiation regulator 1 (Erdr1) is a stress-induced, widely expressed, highly conserved secreted factor found in both humans and mice. Erdr1 is linked with the Hippo-YAP1 signaling. Initially identified as an inducer of hemoglobin synthesis, Erdr1 emerged as a multifunctional protein, especially in immune cells. Although Erdr1 has been implicated in regulating T cells and NK cell function, its role in macrophage remains unclear. This study explored the function and mechanism of Erdr1 in macrophage inflammatory response. The data demonstrated that Erdr1 could promote anti-inflammatory cytokine production, a function that also has been reported by previous research. However, I found Erdr1 also could play a proinflammatory role. The function of Erdr1 in macrophages depends on its dose and cell density. I observed that Erdr1 expression was inhibited in M1 macrophages but was upregulated in M2 macrophages compared with unpolarized macrophages. I hypothesized that Erdr1 balances the inflammatory response by binding with distinct adaptors dependent on varying concentrations. Mechanistically, I demonstrated YAP1 and Mid1 as the two adaptor proteins of Erdr1. The Erdr1-YAP1 interaction promotes anti-inflammatory cytokine production when Erdr1 levels are elevated, whereas the Erdr1-Mid1 interaction induces proinflammatory cytokine production when Erdr1 levels are decreased. This study highlights the effects of Erdr1 on regulating cytokine production from polarized macrophages potentially by regulating YAP1 in the nonclassical Hippo pathway.
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Affiliation(s)
- Yuhang Wang
- Department of Microbiology and Immunology, University of Iowa, IA City, IA
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4
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Wei Y, Li W, Huang J, Braunstein Z, Liu X, Li X, Deiuliis J, Chen J, Min X, Yang H, Gong Q, He L, Liu Z, Dong L, Zhong J. Midline-1 regulates effector T cell motility in experimental autoimmune encephalomyelitis via mTOR/microtubule pathway. Theranostics 2024; 14:1168-1180. [PMID: 38323310 PMCID: PMC10845203 DOI: 10.7150/thno.87130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 01/03/2024] [Indexed: 02/08/2024] Open
Abstract
Background: Effector T cell activation, migration, and proinflammatory cytokine production are crucial steps in autoimmune disorders such as multiple sclerosis (MS). While several therapeutic approaches targeting T cell activation and proinflammatory cytokines have been developed for the treatment of autoimmune diseases, there are no therapeutic agents targeting the migration of effector T cells, largely due to our limited understanding of regulatory mechanisms of T cell migration in autoimmune disease. Here we reported that midline-1 (Mid1) is a key regulator of effector T cell migration in experimental autoimmune encephalomyelitis (EAE), a widely used animal model of MS. Methods: Mid1-/- mice were generated by Crispr-Cas9 technology. T cell-specific Mid1 knockout chimeric mice were generated by adoptive transfer of Mid1-/- T cells into lymphocyte deficient Rag2-/- mice. Mice were either immunized with MOG35-55 (active EAE) or received adoptive transfer of pathogenic T cells (passive EAE) to induce EAE. In vitro Transwell® assay or in vivo footpad injection were used to assess the migration of T cells. Results: Mid1 was significantly increased in the spinal cord of wild-type (Wt) EAE mice and disruption of Mid1 in T cells markedly suppressed the development of both active and passive EAE. Transcriptomic and flow cytometric analyses revealed a marked reduction in effector T cell number in the central nervous system of Mid1-/- mice after EAE induction. Conversely, an increase in the number of T cells was observed in the draining lymph nodes of Mid1-/- mice. Mice that were adoptively transferred with pathogenic Mid1-/- T cells also exhibited milder symptoms of EAE, along with a lower T cell count in the spinal cord. Additionally, disruption of Mid1 significantly inhibited T-cell migration both in vivo and in vitro. RNA sequencing suggests a suppression in multiple inflammatory pathways in Mid1-/- mice, including mTOR signaling that plays a critical role in cell migration. Subsequent experiments confirmed the interaction between Mid1 and mTOR. Suppression of mTOR with rapamycin or microtubule spindle formation with colcemid blunted the regulatory effect of Mid1 on T cell migration. In addition, mTOR agonists MHY1485 and 3BDO restored the migratory deficit caused by Mid1 depletion. Conclusion: Our data suggests that Mid1 regulates effector T cell migration to the central nervous system via mTOR/microtubule pathway in EAE, and thus may serve as a potential therapeutic target for the treatment of MS.
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Affiliation(s)
- Yingying Wei
- Department of Rheumatology and Immunology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
- Cardiovascular Research Institute, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Wenjuan Li
- Department of Rheumatology and Immunology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Jie Huang
- Department of Rheumatology and Immunology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Zachary Braunstein
- Wexner Medical Center, The Ohio State University, Columbus, Ohio 43210, USA
| | - Xinxin Liu
- Department of Rheumatology and Immunology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Xinlu Li
- Department of Rheumatology and Immunology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Jeffrey Deiuliis
- Cardiovascular Research Institute, Case Western Reserve University, Cleveland, Ohio 44106, USA
| | - Jun Chen
- Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine), Shiyan, Hubei 442008, China
| | - Xinwen Min
- Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine), Shiyan, Hubei 442008, China
| | - Handong Yang
- Sinopharm Dongfeng General Hospital, Hubei University of Medicine, Hubei Key Laboratory of Wudang Local Chinese Medicine Research (Hubei University of Medicine), Shiyan, Hubei 442008, China
| | - Quan Gong
- Department of Immunology, School of Medicine, Yangtze University, Jingzhou, Hubei 434023, China
| | - Leya He
- Department of Gastrointestinal Surgery, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Zheng Liu
- Institute of Allergy and Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
- Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Lingli Dong
- Department of Rheumatology and Immunology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
| | - Jixin Zhong
- Department of Rheumatology and Immunology, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
- Cardiovascular Research Institute, Case Western Reserve University, Cleveland, Ohio 44106, USA
- Institute of Allergy and Clinical Immunology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430030, China
- Key Laboratory of Vascular Aging (HUST), Ministry of Education, Wuhan, Hubei 430030, China
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Wang Y. Erdr1 orchestrates macrophage polarization and determines cell fate via dynamic interplay with YAP1 and Mid1. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.17.557960. [PMID: 37781614 PMCID: PMC10541097 DOI: 10.1101/2023.09.17.557960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/03/2023]
Abstract
Erythroid differentiation regulator 1 (Erdr1) is a stress-induced, widely distributed, extremely conserved secreted factor found in both humans and mice. Erdr1 is highly linked with the Hippo-YAP1 signaling. Initially identified as an inducer of hemoglobin synthesis, it has emerged as a multifunctional protein, especially in immune cells. Although Erdr1 has been implicated in T cells and NK cell function, its role in macrophage remains unclear. This study aims to explore the function and mechanism of Erdr1 in IL-1β production in macrophages. Data manifest Erdr1 could play an inhibition role in IL-1β production, which also has been reported by previous research. What significance is we discovered Erdr1 can promote IL-1β production which is associated with Erdr1 dose and cell density. We observed that Erdr1 was inhibited in pro-inflammatory (M1) macrophages but was upregulated in anti-inflammatory (M2) macrophages compared to naive macrophages. We hypothesized that Erdr1 dual drives and modulates IL-1β production by binding with distinct adaptors via concentration change. Mechanistically, we demonstrated that Erdr1 dual regulates IL-1β production by dynamic interaction with YAP1 and Mid1 by distinct domains. Erdr1-YAP1 interplay mediates macrophage M2 polarization by promoting an anti-inflammatory response, enhancing catabolic metabolism, and leading to sterile cell death. Whereas, Erdr1-Mid1 interplay mediates macrophage M1 polarization by initiating a pro-inflammatory response, facilitating anabolic metabolism, and causing inflammatory cell death. This study highlights Erdr1 orchestrates macrophage polarization and determines cell date by regulating YAP1 through non-classical Hippo pathway.
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Affiliation(s)
- Yuhang Wang
- Department of Microbiology and Immunology, University of Iowa, Iowa City, IA 52242, USA
- Department of Pathology, University of Iowa, Iowa City, IA 52242, USA (Current)
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6
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Dudley-Fraser J, Rittinger K. It's a TRIM-endous view from the top: the varied roles of TRIpartite Motif proteins in brain development and disease. Front Mol Neurosci 2023; 16:1287257. [PMID: 38115822 PMCID: PMC10728303 DOI: 10.3389/fnmol.2023.1287257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 11/13/2023] [Indexed: 12/21/2023] Open
Abstract
The tripartite motif (TRIM) protein family members have been implicated in a multitude of physiologies and pathologies in different tissues. With diverse functions in cellular processes including regulation of signaling pathways, protein degradation, and transcriptional control, the impact of TRIM dysregulation can be multifaceted and complex. Here, we focus on the cellular and molecular roles of TRIMs identified in the brain in the context of a selection of pathologies including cancer and neurodegeneration. By examining each disease in parallel with described roles in brain development, we aim to highlight fundamental common mechanisms employed by TRIM proteins and identify opportunities for therapeutic intervention.
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Affiliation(s)
- Jane Dudley-Fraser
- Molecular Structure of Cell Signalling Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Katrin Rittinger
- Molecular Structure of Cell Signalling Laboratory, The Francis Crick Institute, London, United Kingdom
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7
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Deisseroth CA, Lee WS, Kim J, Jeong HH, Dhindsa RS, Wang J, Zoghbi HY, Liu Z. Literature-based predictions of Mendelian disease therapies. Am J Hum Genet 2023; 110:1661-1672. [PMID: 37741276 PMCID: PMC10577072 DOI: 10.1016/j.ajhg.2023.08.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 08/31/2023] [Accepted: 08/31/2023] [Indexed: 09/25/2023] Open
Abstract
In the effort to treat Mendelian disorders, correcting the underlying molecular imbalance may be more effective than symptomatic treatment. Identifying treatments that might accomplish this goal requires extensive and up-to-date knowledge of molecular pathways-including drug-gene and gene-gene relationships. To address this challenge, we present "parsing modifiers via article annotations" (PARMESAN), a computational tool that searches PubMed and PubMed Central for information to assemble these relationships into a central knowledge base. PARMESAN then predicts putatively novel drug-gene relationships, assigning an evidence-based score to each prediction. We compare PARMESAN's drug-gene predictions to all of the drug-gene relationships displayed by the Drug-Gene Interaction Database (DGIdb) and show that higher-scoring relationship predictions are more likely to match the directionality (up- versus down-regulation) indicated by this database. PARMESAN had more than 200,000 drug predictions scoring above 8 (as one example cutoff), for more than 3,700 genes. Among these predicted relationships, 210 were registered in DGIdb and 201 (96%) had matching directionality. This publicly available tool provides an automated way to prioritize drug screens to target the most-promising drugs to test, thereby saving time and resources in the development of therapeutics for genetic disorders.
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Affiliation(s)
- Cole A Deisseroth
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Won-Seok Lee
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA
| | - Jiyoen Kim
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hyun-Hwan Jeong
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Ryan S Dhindsa
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Pathology and Immunology, Baylor College of Medicine, 1 Baylor Plaza, Houston, TX 77030, USA
| | - Julia Wang
- Medical Scientist Training Program, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Huda Y Zoghbi
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Integrative Molecular and Biomedical Sciences Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Zhandong Liu
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA.
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8
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Kaur A, Gladu EM, Wright KM, Webb JA, Massiah MA. B-box1 Domain of MID1 Interacts with the Ube2D1 E2 Enzyme Differently Than RING E3 Ligases. Biochemistry 2023; 62:1012-1025. [PMID: 36820504 DOI: 10.1021/acs.biochem.2c00693] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The MID1 TRIM protein is important for ventral midline development in vertebrates, and mutations of its B-box1 domain result in several birth defects. The B-box1 domain of the human MID1 protein binds two zinc atoms and adopt a similar ββα-RING structure. This domain is required for the efficient ubiquitination of protein phosphatase 2A, alpha4, and fused kinase. Considering the structural similarity, the MID1 B-box1 domain exhibits mono-autoubiquitination activity, in contrast to poly-autoubiquitination observed for RING E3 ligases. To understand its mechanism of action, the interaction of the B-box1 domain with Ube2D1 (UbcH5a, E2), a preferred E2 ligase, is investigated. Using isothermal titration calorimetry, the MID1 RING and B-box1 domains were observed to have similar binding affinities with the Ube2D1 protein. However, NMR 15N-1H Heteronuclear Single Quantum Coherence titration, 15N relaxation data, and High Ambiguity Driven protein-protein DOCKing (HADDOCK) calculations show the B-box1 domain binding on a surface distinct from where RING domains bind. The novel binding interaction shows the B-box1 domain partially overlapping the noncovalent Ube2D1 and a ubiquitin binding site that is necessary for poly-autoubiquitination activity. The B-box1 domain also displaces the ubiquitin from the Ube2D1 protein. These studies reveal a novel binding interaction between the zinc-binding ββα-fold B-box1 domain and the Ube2D enzyme family and that this difference in binding, compared to RING E3 ligases, provides a rationale for its auto-monoubiquitination E3 ligase activity.
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Affiliation(s)
- Anupreet Kaur
- Department of Chemistry, George Washington University, 800 22nd St NW, Washington, D.C. 20052, United States
| | - Erin M Gladu
- Department of Chemistry, George Washington University, 800 22nd St NW, Washington, D.C. 20052, United States
| | - Katharine M Wright
- Department of Chemistry, George Washington University, 800 22nd St NW, Washington, D.C. 20052, United States
| | - Jessica A Webb
- Department of Chemistry, George Washington University, 800 22nd St NW, Washington, D.C. 20052, United States
| | - Michael A Massiah
- Department of Chemistry, George Washington University, 800 22nd St NW, Washington, D.C. 20052, United States
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9
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Opitz syndrome: improving clinical interpretation of intronic variants in MID1 gene. Pediatr Res 2022; 93:1208-1215. [PMID: 35953512 DOI: 10.1038/s41390-022-02237-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 07/12/2022] [Accepted: 07/24/2022] [Indexed: 03/05/2023]
Abstract
BACKGROUND Loss-of-function variants in MID1 are the most common cause of Opitz G/BBB syndrome (OS). The interpretation of intronic variants affecting the splicing is a rising issue in OS. METHODS Exon sequencing of a 2-year-old boy with OS showed that he was a carrier of the de novo c.1286-10G>T variant in MID1. In silico predictions and minigene assays explored the effect of the variant on splicing. The minigene approach was also applied to two previously identified MID1 c.864+1G>T and c.1285+1G>T variants. RESULTS Minigene assay demonstrated that the c.1286-10G>T variant generated the inclusion of eight nucleotides that predicted generation of a frameshift. The c.864+1G>T and c.1285+1G>T variants resulted in an in-frame deletion predicted to generate a shorter MID1 protein. In hemizygous males, this allowed reclassification of all the identified variants from "of unknown significance" to "likely pathogenic." CONCLUSIONS Minigene assay supports functional effects from MID1 intronic variants. This paves the way to the introduction of similar second-tier investigations in the molecular diagnostics workflow of OS. IMPACT Causative intronic variants in MID1 are rarely investigated in Opitz syndrome. MID1 is not expressed in blood and mRNA studies are hardly accessible in routine diagnostics. Minigene assay is an alternative for assessing the effect of intronic variants on splicing. This is the first study characterizing the molecular consequences of three MID1 variants for diagnostic purposes and demonstrating the efficacy of minigene assays in supporting their clinical interpretation. Review of the criteria according to the American College of Medical Genetics reassessed all variants as likely pathogenic.
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10
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Heinz A, Schilling J, van Roon-Mom W, Krauß S. The MID1 Protein: A Promising Therapeutic Target in Huntington's Disease. Front Genet 2021; 12:761714. [PMID: 34659371 PMCID: PMC8517220 DOI: 10.3389/fgene.2021.761714] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 09/21/2021] [Indexed: 11/13/2022] Open
Abstract
Huntington's disease (HD) is caused by an expansion mutation of a CAG repeat in exon 1 of the huntingtin (HTT) gene, that encodes an expanded polyglutamine tract in the HTT protein. HD is characterized by progressive psychiatric and cognitive symptoms associated with a progressive movement disorder. HTT is ubiquitously expressed, but the pathological changes caused by the mutation are most prominent in the central nervous system. Since the mutation was discovered, research has mainly focused on the mutant HTT protein. But what if the polyglutamine protein is not the only cause of the neurotoxicity? Recent studies show that the mutant RNA transcript is also involved in cellular dysfunction. Here we discuss the abnormal interaction of the mutant HTT transcript with a protein complex containing the MID1 protein. MID1 aberrantly binds to CAG repeats and this binding increases with CAG repeat length. Since MID1 is a translation regulator, association of the MID1 complex stimulates translation of mutant HTT mRNA, resulting in an overproduction of polyglutamine protein. Thus, blocking the interaction between MID1 and mutant HTT mRNA is a promising therapeutic approach. Additionally, we show that MID1 expression in the brain of both HD patients and HD mice is aberrantly increased. This finding further supports the concept of blocking the interaction between MID1 and mutant HTT mRNA to counteract mutant HTT translation as a valuable therapeutic strategy. In line, recent studies in which either compounds affecting the assembly of the MID1 complex or molecules targeting HTT RNA, show promising results.
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Affiliation(s)
- Annika Heinz
- University of Siegen, Institute of Biology, Human Biology / Neurobiology, Siegen, Germany
| | - Judith Schilling
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Willeke van Roon-Mom
- Leiden University Medical Center, Department of Human Genetics, Leiden, Netherlands
| | - Sybille Krauß
- University of Siegen, Institute of Biology, Human Biology / Neurobiology, Siegen, Germany
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11
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Chen Q, Gao C, Wang M, Fei X, Zhao N. TRIM18-Regulated STAT3 Signaling Pathway via PTP1B Promotes Renal Epithelial-Mesenchymal Transition, Inflammation, and Fibrosis in Diabetic Kidney Disease. Front Physiol 2021; 12:709506. [PMID: 34434118 PMCID: PMC8381599 DOI: 10.3389/fphys.2021.709506] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/15/2021] [Indexed: 01/15/2023] Open
Abstract
Diabetic kidney disease (DKD) has become a key cause of end-stage renal disease worldwide. Inflammation and fibrosis have been shown to play important roles in the pathogenesis of DKD. MID1, also known as TRIM18, is an E3 ubiquitin ligase of the tripartite motif (TRIM) subfamily of RING-containing proteins and increased in renal tubule in patients with DKD. However, the function and molecular mechanism of TRIM18 in DKD remain unexplored. Herein we report that TRIM18 expression levels were increased in patients with DKD. An animal study confirms that TRIM18 is involved in kidney injury and fibrosis in diabetic mice. TRIM18 knockdown inhibits high glucose (HG)-induced epithelial–mesenchymal transition (EMT), inflammation, and fibrosis of HK-2 cells. This is accompanied by decreased levels of tumor necrosis factor alpha, interleukin-6, hydroxyproline (Hyp), connective tissue growth factor, and α-smooth muscle actin. Additionally, TRIM18 knockdown inhibits HG-induced increase in the phosphorylated-/total signal transducer and activator of transcription (STAT3). Treatment with niclosamide (STAT3 inhibitor) or protein tyrosine phosphatase-1B (PTP1B) overexpression blocked the TRIM18 induced EMT, inflammation and fibrosis. Co-immunoprecipitation and Western blot assays showed that TRIM18 promoted the ubiquitination of PTP1B. These findings highlight the importance of the TRIM18/PTP1B/STAT3 signaling pathway in DKD and can help in the development of new therapeutics for DKD treatment.
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Affiliation(s)
- Qi Chen
- Department of Nephrology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Chan Gao
- Department of Nephrology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ming Wang
- Department of Nephrology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiao Fei
- Department of Nephrology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Ning Zhao
- Department of Nephrology, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, China
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12
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Zheng J, Tian N, Liu F, Zhang Y, Su J, Gao Y, Deng M, Wei L, Ye J, Li H, Wang JZ. A novel dephosphorylation targeting chimera selectively promoting tau removal in tauopathies. Signal Transduct Target Ther 2021; 6:269. [PMID: 34262014 PMCID: PMC8280143 DOI: 10.1038/s41392-021-00669-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 01/04/2021] [Accepted: 01/18/2021] [Indexed: 11/12/2022] Open
Abstract
Intraneuronal accumulation of hyperphosphorylated tau is a hallmark pathology shown in over twenty neurodegenerative disorders, collectively termed as tauopathies, including the most common Alzheimer's disease (AD). Therefore, selectively removing or reducing hyperphosphorylated tau is promising for therapies of AD and other tauopathies. Here, we designed and synthesized a novel DEPhosphorylation TArgeting Chimera (DEPTAC) to specifically facilitate the binding of tau to Bα-subunit-containing protein phosphatase 2A (PP2A-Bα), the most active tau phosphatase in the brain. The DEPTAC exhibited high efficiency in dephosphorylating tau at multiple AD-associated sites and preventing tau accumulation both in vitro and in vivo. Further studies revealed that DEPTAC significantly improved microtubule assembly, neurite plasticity, and hippocampus-dependent learning and memory in transgenic mice with inducible overexpression of truncated and neurotoxic human tau N368. Our data provide a strategy for selective removal of the hyperphosphorylated tau, which sheds new light for the targeted therapy of AD and related-tauopathies.
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Affiliation(s)
- Jie Zheng
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
- Department of Pharmacology, Key Laboratory of Basic Pharmacology of Ministry of Education, Joint International Research Laboratory of Ethnomedicine of Ministry of Education, Key Laboratory of Basic Pharmacology of Guizhou Province, Zunyi Medical University, Zunyi, China.
| | - Na Tian
- Department of Histology and Embryology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Liu
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yidian Zhang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jingfen Su
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yang Gao
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mingmin Deng
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Linyu Wei
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jingwang Ye
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Honglian Li
- Department of Histology and Embryology, Key Laboratory of Ministry of Education for Neurological Disorders, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Department of Pathophysiology, School of Basic Medicine, Key Laboratory of Education Ministry of China/Hubei Province for Neurological Disorders, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.
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13
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Huntingtin and Its Role in Mechanisms of RNA-Mediated Toxicity. Toxins (Basel) 2021; 13:toxins13070487. [PMID: 34357961 PMCID: PMC8310054 DOI: 10.3390/toxins13070487] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/09/2021] [Accepted: 07/11/2021] [Indexed: 12/20/2022] Open
Abstract
Huntington’s disease (HD) is caused by a CAG-repeat expansion mutation in the Huntingtin (HTT) gene. It is characterized by progressive psychiatric and neurological symptoms in combination with a progressive movement disorder. Despite the ubiquitous expression of HTT, pathological changes occur quite selectively in the central nervous system. Since the discovery of HD more than 150 years ago, a lot of research on molecular mechanisms contributing to neurotoxicity has remained the focal point. While traditionally, the protein encoded by the HTT gene remained the cynosure for researchers and was extensively reviewed elsewhere, several studies in the last few years clearly indicated the contribution of the mutant RNA transcript to cellular dysfunction as well. In this review, we outline recent studies on RNA-mediated molecular mechanisms that are linked to cellular dysfunction in HD models. These mechanisms include mis-splicing, aberrant translation, deregulation of the miRNA machinery, deregulated RNA transport and abnormal regulation of mitochondrial RNA. Furthermore, we summarize recent therapeutical approaches targeting the mutant HTT transcript. While currently available treatments are of a palliative nature only and do not halt the disease progression, recent clinical studies provide hope that these novel RNA-targeting strategies will lead to better therapeutic approaches.
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Role and Perspective of Molecular Simulation-Based Investigation of RNA-Ligand Interaction: From Small Molecules and Peptides to Photoswitchable RNA Binding. Molecules 2021; 26:molecules26113384. [PMID: 34205049 PMCID: PMC8199858 DOI: 10.3390/molecules26113384] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/28/2021] [Accepted: 06/01/2021] [Indexed: 12/15/2022] Open
Abstract
Aberrant RNA–protein complexes are formed in a variety of diseases. Identifying the ligands that interfere with their formation is a valuable therapeutic strategy. Molecular simulation, validated against experimental data, has recently emerged as a powerful tool to predict both the pose and energetics of such ligands. Thus, the use of molecular simulation may provide insight into aberrant molecular interactions in diseases and, from a drug design perspective, may allow for the employment of less wet lab resources than traditional in vitro compound screening approaches. With regard to basic research questions, molecular simulation can support the understanding of the exact molecular interaction and binding mode. Here, we focus on examples targeting RNA–protein complexes in neurodegenerative diseases and viral infections. These examples illustrate that the strategy is rather general and could be applied to different pharmacologically relevant approaches. We close this study by outlining one of these approaches, namely the light-controllable association of small molecules with RNA, as an emerging approach in RNA-targeting therapy.
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15
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mTOR Driven Gene Transcription Is Required for Cholesterol Production in Neurons of the Developing Cerebral Cortex. Int J Mol Sci 2021; 22:ijms22116034. [PMID: 34204880 PMCID: PMC8199781 DOI: 10.3390/ijms22116034] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/15/2021] [Accepted: 05/28/2021] [Indexed: 12/13/2022] Open
Abstract
Dysregulated mammalian target of rapamycin (mTOR) activity is associated with various neurodevelopmental disorders ranging from idiopathic autism spectrum disorders (ASD) to syndromes caused by single gene defects. This suggests that maintaining mTOR activity levels in a physiological range is essential for brain development and functioning. Upon activation, mTOR regulates a variety of cellular processes such as cell growth, autophagy, and metabolism. On a molecular level, however, the consequences of mTOR activation in the brain are not well understood. Low levels of cholesterol are associated with a wide variety of neurodevelopmental disorders. We here describe numerous genes of the sterol/cholesterol biosynthesis pathway to be transcriptionally regulated by mTOR complex 1 (mTORC1) signaling in vitro in primary neurons and in vivo in the developing cerebral cortex of the mouse. We find that these genes are shared targets of the transcription factors SREBP, SP1, and NF-Y. Prenatal as well as postnatal mTORC1 inhibition downregulated expression of these genes which directly translated into reduced cholesterol levels, pointing towards a substantial metabolic function of the mTORC1 signaling cascade. Altogether, our results indicate that mTORC1 is an essential transcriptional regulator of the expression of sterol/cholesterol biosynthesis genes in the developing brain. Altered expression of these genes may be an important factor contributing to the pathogenesis of neurodevelopmental disorders associated with dysregulated mTOR signaling.
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16
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Differential accumulation of tau pathology between reciprocal F1 hybrids of rTg4510 mice. Sci Rep 2021; 11:9623. [PMID: 33953293 PMCID: PMC8100160 DOI: 10.1038/s41598-021-89142-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 04/22/2021] [Indexed: 02/03/2023] Open
Abstract
Tau, a family of microtubule-associated proteins, forms abnormal intracellular inclusions, so-called tau pathology, in a range of neurodegenerative diseases collectively known as tauopathies. The rTg4510 mouse model is a well-characterized bitransgenic F1 hybrid mouse model of tauopathy, which was obtained by crossing a Camk2α-tTA mouse line (on a C57BL/6 J background) with a tetO-MAPT*P301L mouse line (on a FVB/NJ background). The aim of this study was to investigate the effects of the genetic background and sex on the accumulation of tau pathology in reciprocal F1 hybrids of rTg4510 mice, i.e., rTg4510 on the (C57BL/6 J × FVB/NJ)F1 background (rTg4510_CxF) and on the (FVB/NJ × C57BL/6 J)F1 background (rTg4510_FxC). As compared with rTg4510_CxF mice, the rTg4510_FxC mice showed marked levels of tau pathology in the forebrain. Biochemical analyses indicated that the accumulation of abnormal tau species was accelerated in rTg4510_FxC mice. There were strong effects of the genetic background on the differential accumulation of tau pathology in rTg4510 mice, while sex had no apparent effect. Interestingly, midline-1 (Mid1) was identified as a candidate gene associated with this difference and exhibited significant up/downregulation according to the genetic background. Mid1 silencing with siRNA induced pathological phosphorylation of tau in HEK293T cells that stably expressed human tau with the P301L mutation, suggesting the role of Mid1 in pathological alterations of tau. Elucidation of the underlying mechanisms will provide novel insights into the accumulation of tau pathology and is expected to be especially informative to researchers for the continued development of therapeutic interventions for tauopathies.
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17
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Etchegaray E, Naville M, Volff JN, Haftek-Terreau Z. Transposable element-derived sequences in vertebrate development. Mob DNA 2021; 12:1. [PMID: 33407840 PMCID: PMC7786948 DOI: 10.1186/s13100-020-00229-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/15/2020] [Indexed: 12/14/2022] Open
Abstract
Transposable elements (TEs) are major components of all vertebrate genomes that can cause deleterious insertions and genomic instability. However, depending on the specific genomic context of their insertion site, TE sequences can sometimes get positively selected, leading to what are called "exaptation" events. TE sequence exaptation constitutes an important source of novelties for gene, genome and organism evolution, giving rise to new regulatory sequences, protein-coding exons/genes and non-coding RNAs, which can play various roles beneficial to the host. In this review, we focus on the development of vertebrates, which present many derived traits such as bones, adaptive immunity and a complex brain. We illustrate how TE-derived sequences have given rise to developmental innovations in vertebrates and how they thereby contributed to the evolutionary success of this lineage.
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Affiliation(s)
- Ema Etchegaray
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France.
| | - Magali Naville
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France
| | - Jean-Nicolas Volff
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France
| | - Zofia Haftek-Terreau
- Institut de Genomique Fonctionnelle de Lyon, Univ Lyon, CNRS UMR 5242, Ecole Normale Superieure de Lyon, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364, Lyon, France
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18
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Pirkmajer S, Bezjak K, Matkovič U, Dolinar K, Jiang LQ, Miš K, Gros K, Milovanova K, Pirkmajer KP, Marš T, Kapilevich L, Chibalin AV. Ouabain Suppresses IL-6/STAT3 Signaling and Promotes Cytokine Secretion in Cultured Skeletal Muscle Cells. Front Physiol 2020; 11:566584. [PMID: 33101052 PMCID: PMC7544989 DOI: 10.3389/fphys.2020.566584] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/25/2020] [Indexed: 12/16/2022] Open
Abstract
The cardiotonic steroids (CTS), such as ouabain and marinobufagenin, are thought to be adrenocortical hormones secreted during exercise and the stress response. The catalytic α-subunit of Na,K-ATPase (NKA) is a CTS receptor, whose largest pool is located in skeletal muscles, indicating that muscles are a major target for CTS. Skeletal muscles contribute to adaptations to exercise by secreting interleukin-6 (IL-6) and plethora of other cytokines, which exert paracrine and endocrine effects in muscles and non-muscle tissues. Here, we determined whether ouabain, a prototypical CTS, modulates IL-6 signaling and secretion in the cultured human skeletal muscle cells. Ouabain (2.5–50 nM) suppressed the abundance of STAT3, a key transcription factor downstream of the IL-6 receptor, as well as its basal and IL-6-stimulated phosphorylation. Conversely, ouabain (50 nM) increased the phosphorylation of ERK1/2, Akt, p70S6K, and S6 ribosomal protein, indicating activation of the ERK1/2 and the Akt-mTOR pathways. Proteasome inhibitor MG-132 blocked the ouabain-induced suppression of the total STAT3, but did not prevent the dephosphorylation of STAT3. Ouabain (50 nM) suppressed hypoxia-inducible factor-1α (HIF-1α), a modulator of STAT3 signaling, but gene silencing of HIF-1α and/or its partner protein HIF-1β did not mimic effects of ouabain on the phosphorylation of STAT3. Ouabain (50 nM) failed to suppress the phosphorylation of STAT3 and HIF-1α in rat L6 skeletal muscle cells, which express the ouabain-resistant α1-subunit of NKA. We also found that ouabain (100 nM) promoted the secretion of IL-6, IL-8, GM-CSF, and TNF-α from the skeletal muscle cells of healthy subjects, and the secretion of GM-CSF from cells of subjects with the type 2 diabetes. Marinobufagenin (10 nM), another important CTS, did not alter the secretion of these cytokines. In conclusion, our study shows that ouabain suppresses the IL-6 signaling via STAT3, but promotes the secretion of IL-6 and other cytokines, which might represent a negative feedback in the IL-6/STAT3 pathway. Collectively, our results implicate a role for CTS and NKA in regulation of the IL-6 signaling and secretion in skeletal muscle.
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Affiliation(s)
- Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Katja Bezjak
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Urška Matkovič
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Klemen Dolinar
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Lake Q Jiang
- Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
| | - Katarina Miš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Katarina Gros
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Kseniya Milovanova
- Department of Sports and Health Tourism, Sports Physiology and Medicine, National Research Tomsk State University, Tomsk, Russia
| | - Katja Perdan Pirkmajer
- Department of Rheumatology, University Medical Centre Ljubljana, Ljubljana, Slovenia.,Department of Internal Medicine, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Tomaž Marš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Leonid Kapilevich
- Department of Sports and Health Tourism, Sports Physiology and Medicine, National Research Tomsk State University, Tomsk, Russia.,Central Scientific Laboratory, Siberian State Medical University, Tomsk, Russia
| | - Alexander V Chibalin
- Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden
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Baldini R, Mascaro M, Meroni G. The MID1 gene product in physiology and disease. Gene 2020; 747:144655. [PMID: 32283114 PMCID: PMC8011326 DOI: 10.1016/j.gene.2020.144655] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/22/2020] [Accepted: 04/06/2020] [Indexed: 12/23/2022]
Abstract
MID1 is an E3 ubiquitin ligase of the Tripartite Motif (TRIM) subfamily of RING-containing proteins, hence also known as TRIM18. MID1 is a microtubule-binding protein found in complex with the catalytic subunit of PP2A (PP2Ac) and its regulatory subunit alpha 4 (α4). To date, several substrates and interactors of MID1 have been described, providing evidence for the involvement of MID1 in a plethora of essential biological processes, especially during embryonic development. Mutations in the MID1 gene are responsible of the X-linked form of Opitz syndrome (XLOS), a multiple congenital disease characterised by defects in the development of midline structures during embryogenesis. Here, we review MID1-related physiological mechanisms as well as the pathological implication of the MID1 gene in XLOS and in other clinical conditions.
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Affiliation(s)
- Rossella Baldini
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Martina Mascaro
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Germana Meroni
- Department of Life Sciences, University of Trieste, Trieste, Italy.
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20
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Lai GR, Lee YF, Yan SJ, Ting HJ. Active vitamin D induces gene-specific hypomethylation in prostate cancer cells developing vitamin D resistance. Am J Physiol Cell Physiol 2020; 318:C836-C847. [PMID: 32159363 DOI: 10.1152/ajpcell.00522.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Prostate cancer (PCa) is a leading cause of cancer death in men. Despite the antiproliferative effects of 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] on PCa, accumulating evidence indicates that 1,25(OH)2D3 promotes cancer progression by increasing genome plasticity. Our investigation of epigenetic changes associated with vitamin D insensitivity found that 1,25(OH)2D3 treatment reduced the expression levels and activities of DNA methyltransferases 1 and 3B (DNMT1 and DNMT3B, respectively). In silico analysis and reporter assay confirmed that 1,25(OH)2D3 downregulated transcriptional activation of the DNMT3B promoter and upregulated microRNAs targeting the 3'-untranslated regions of DNMT3B. We then profiled DNA methylation in the vitamin D-resistant PC-3 cells and a resistant PCa cell model generated by long-term 1,25(OH)2D3 exposure. Several candidate genes were found to be hypomethylated and overexpressed in vitamin D-resistant PCa cells compared with vitamin D-sensitive cells. Most of the identified genes were associated with mammalian target of rapamycin (mTOR) signaling activation, which is known to promote cancer progression. Among them, we found that inhibition of ribosomal protein S6 kinase A1 (RPS6KA1) promoted vitamin D sensitivity in PC-3 cells. Furthermore, The Cancer Genome Atlas (TCGA) prostate cancer data set demonstrated that midline 1 (MID1) expression is positively correlated with tumor stage. Overall, our study reveals an inhibitory mechanism of 1,25(OH)2D3 on DNMT3B, which may contribute to vitamin D resistance in PCa.
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Affiliation(s)
- Guan-Rong Lai
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Yi-Fen Lee
- Department of Urology, Pathology, and Wilmot Cancer Cancer, University of Rochester, Rochester, New York
| | - Shian-Jang Yan
- Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Huei-Ju Ting
- Department of Biological Sciences and Technology, National University of Tainan, Tainan, Taiwan, Republic of China
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21
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TRIM E3 Ubiquitin Ligases in Rare Genetic Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1233:311-325. [PMID: 32274764 DOI: 10.1007/978-3-030-38266-7_14] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The TRIM family comprises proteins characterized by the presence of the tripartite motif composed of a RING domain, one or two B-box domains and a coiled-coil region. The TRIM shared domain structure underscores a common biochemical function as E3 ligase within the ubiquitination cascade. The TRIM proteins represent one of the largest E3 ligase families counting in human more than 70 members. These proteins are implicated in a plethora of cellular processes such as apoptosis, cell cycle regulation, muscular physiology, and innate immune response. Consistently, their alteration results in several pathological conditions emphasizing their medical relevance. Here, the genetic and pathogenetic mechanisms of rare disorders directly caused by mutations in TRIM genes will be reviewed. These diseases fall into different pathological areas, from malformation birth defects due to developmental abnormalities, to neurological disorders and progressive teenage neuromuscular disorders. In many instances, TRIM E3 ligases act on several substrates thus exerting pleiotropic activities: the need of unraveling disease-specific TRIM pathways for a precise targeting therapy avoiding dramatic side effects will be discussed.
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22
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Posey KL, Coustry F, Veerisetty AC, Hossain MG, Gambello MJ, Hecht JT. Novel mTORC1 Mechanism Suggests Therapeutic Targets for COMPopathies. THE AMERICAN JOURNAL OF PATHOLOGY 2019; 189:132-146. [PMID: 30553437 DOI: 10.1016/j.ajpath.2018.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/20/2018] [Accepted: 09/17/2018] [Indexed: 02/06/2023]
Abstract
Cartilage oligomeric matrix protein (COMP) is a large, multifunctional extracellular protein that, when mutated, is retained in the rough endoplasmic reticulum (ER). This retention elicits ER stress, inflammation, and oxidative stress, resulting in dysfunction and death of growth plate chondrocytes. While identifying the cellular pathologic mechanisms underlying the murine mutant (MT)-COMP model of pseudoachondroplasia, increased midline-1 (MID1) expression and mammalian target of rapamycin complex 1 (mTORC1) signaling was found. This novel role for MID1/mTORC1 signaling was investigated since treatments shown to repress the pathology also reduced Mid1/mTORC1. Although ER stress-inducing drugs or tumor necrosis factor α (TNFα) in rat chondrosarcoma cells increased Mid1, oxidative stress did not, establishing that ER stress- or TNFα-driven inflammation alone is sufficient to elevate MID1 expression. Since MID1 ubiquitinates protein phosphatase 2A (PP2A), a negative regulator of mTORC1, PP2A was evaluated in MT-COMP growth plate chondrocytes. PP2A was decreased, indicating de-repression of mTORC1 signaling. Rapamycin treatment in MT-COMP mice reduced mTORC1 signaling and intracellular retention of COMP, and increased proliferation, but did not change inflammatory markers IL-16 and eosinophil peroxidase. Lastly, mRNA from tuberous sclerosis-1/2-null mice brain tissue exhibiting ER stress had increased Mid1 expression, confirming the relationship between ER stress and MID1/mTORC1 signaling. These findings suggest a mechanistic link between ER stress and MID1/mTORC1 signaling that has implications extending to other conditions involving ER stress.
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Affiliation(s)
- Karen L Posey
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas.
| | - Francoise Coustry
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas
| | - Alka C Veerisetty
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas
| | - Mohammad G Hossain
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas
| | - Michael J Gambello
- Human Genetics and Pediatrics, Emory University School of Medicine, Atlanta, Georgia
| | - Jacqueline T Hecht
- Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center, Houston, Texas; School of Dentistry, University of Texas Health Science Center, Houston, Texas
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23
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Park JG, Aziz N, Cho JY. MKK7, the essential regulator of JNK signaling involved in cancer cell survival: a newly emerging anticancer therapeutic target. Ther Adv Med Oncol 2019; 11:1758835919875574. [PMID: 31579105 PMCID: PMC6759727 DOI: 10.1177/1758835919875574] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Accepted: 08/19/2019] [Indexed: 01/02/2023] Open
Abstract
One of the mitogen-activated protein kinases (MAPKs), c-Jun NH2-terminal protein kinase (JNK) plays an important role in regulating cell fate, such as proliferation, differentiation, development, transformation, and apoptosis. Its activity is induced through the interaction of MAPK kinase kinases (MAP3Ks), MAPK kinases (MAP2Ks), and various scaffolding proteins. Because of the importance of the JNK cascade to intracellular bioactivity, many studies have been conducted to reveal its precise intracellular functions and mechanisms, but its regulatory mechanisms remain elusive. In this review, we discuss the molecular characterization, activation process, and physiological functions of mitogen-activated protein kinase kinase 7 (MKK7), the MAP2K that most specifically controls the activity of JNK. Understanding the role of MKK7/JNK signaling in physiological conditions could spark new hypotheses for targeted anticancer therapies.
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Affiliation(s)
- Jae Gwang Park
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Nur Aziz
- Department of Integrative Biotechnology, Sungkyunkwan University, Suwon, Republic of Korea
| | - Jae Youl Cho
- Department of Integrative Biotechnology, Sungkyunkwan University, 2066 Seobu-ro, Suwon 16419, Republic of Korea
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24
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Zanchetta ME, Meroni G. Emerging Roles of the TRIM E3 Ubiquitin Ligases MID1 and MID2 in Cytokinesis. Front Physiol 2019; 10:274. [PMID: 30941058 PMCID: PMC6433704 DOI: 10.3389/fphys.2019.00274] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 02/28/2019] [Indexed: 11/13/2022] Open
Abstract
Ubiquitination is a post-translational modification that consists of ubiquitin attachment to target proteins through sequential steps catalysed by activating (E1), conjugating (E2), and ligase (E3) enzymes. Protein ubiquitination is crucial for the regulation of many cellular processes not only by promoting proteasomal degradation of substrates but also re-localisation of cellular factors and modulation of protein activity. Great importance in orchestrating ubiquitination relies on E3 ligases as these proteins recognise the substrate that needs to be modified at the right time and place. Here we focus on two members of the TRIpartite Motif (TRIM) family of RING E3 ligases, MID1, and MID2. We discuss the recent findings on these developmental disease-related proteins analysing the link between their activity on essential factors and the regulation of cytokinesis highlighting the possible consequence of alteration of this process in pathological conditions.
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Affiliation(s)
| | - Germana Meroni
- Department of Life Sciences, University of Trieste, Trieste, Italy
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25
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Sekiguchi T, Furuno N, Ishii T, Hirose E, Sekiguchi F, Wang Y, Kobayashi H. RagA, an mTORC1 activator, interacts with a hedgehog signaling protein, WDR35/IFT121. Genes Cells 2019; 24:151-161. [DOI: 10.1111/gtc.12663] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 12/12/2018] [Accepted: 12/13/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Takeshi Sekiguchi
- Department of Molecular Biology, Graduate School of Medical Sciences Kyushu University Fukuoka Japan
| | - Nobuaki Furuno
- Laboratory for Amphibian Biology, Graduate School of Science Hiroshima University Higashihiroshima Japan
| | - Takashi Ishii
- Department of BiochemistryFukuoka Dental College Fukuoka Japan
| | - Eiji Hirose
- Faculty of Health Promotional Sciences Tokoha University Kitaku, Shizuoka Japan
| | - Fumiko Sekiguchi
- Department of Molecular Biology, Graduate School of Medical Sciences Kyushu University Fukuoka Japan
| | - Yonggang Wang
- Department of Molecular Biology, Graduate School of Medical Sciences Kyushu University Fukuoka Japan
| | - Hideki Kobayashi
- Department of Human Nutrition, Faculty of Contemporary Life ScienceChugoku‐Gakuen University Okayama Japan
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26
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Yu X, Teng XL, Wang F, Zheng Y, Qu G, Zhou Y, Hu Z, Wu Z, Chang Y, Chen L, Li HB, Su B, Lu L, Liu Z, Sun SC, Zou Q. Metabolic control of regulatory T cell stability and function by TRAF3IP3 at the lysosome. J Exp Med 2018; 215:2463-2476. [PMID: 30115741 PMCID: PMC6122976 DOI: 10.1084/jem.20180397] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 06/25/2018] [Accepted: 08/06/2018] [Indexed: 01/08/2023] Open
Abstract
Metabolic programs are crucial for regulatory T (T reg) cell stability and function, but the underlying mechanisms that regulate T reg cell metabolism are elusive. Here, we report that lysosomal TRAF3IP3 acts as a pivotal regulator in the maintenance of T reg cell metabolic fitness. T reg-specific deletion of Traf3ip3 impairs T reg cell function, causing the development of inflammatory disorders and stronger antitumor T cell responses in mice. Excessive mechanistic target of rapamycin complex 1 (mTORC1)-mediated hyper-glycolytic metabolism is responsible for the instability of TRAF3IP3-deficient T reg cells. Mechanistically, TRAF3IP3 restricts mTORC1 signaling by recruiting the serine-threonine phosphatase catalytic subunit (PP2Ac) to the lysosome, thereby facilitating the interaction of PP2Ac with the mTORC1 component Raptor. Our results define TRAF3IP3 as a metabolic regulator in T reg cell stability and function and suggest a lysosome-specific mTORC1 signaling mechanism that regulates T reg cell metabolism.
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Affiliation(s)
- Xiaoyan Yu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Lu Teng
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Feixiang Wang
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuhan Zheng
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Guojun Qu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Zhou
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhilin Hu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhongqiu Wu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuzhou Chang
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lei Chen
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Hua-Bing Li
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Bing Su
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Liming Lu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhiduo Liu
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shao-Cong Sun
- Department of Immunology, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Qiang Zou
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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27
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Cross Talk Networks of Mammalian Target of Rapamycin Signaling With the Ubiquitin Proteasome System and Their Clinical Implications in Multiple Myeloma. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 343:219-297. [PMID: 30712673 DOI: 10.1016/bs.ircmb.2018.06.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Multiple myeloma (MM) is the second most common hematological malignancy and results from the clonal amplification of plasma cells. Despite recent advances in treatment, MM remains incurable with a median survival time of only 5-6years, thus necessitating further insights into MM biology and exploitation of novel therapeutic approaches. Both the ubiquitin proteasome system (UPS) and the PI3K/Akt/mTOR signaling pathways have been implicated in the pathogenesis, and treatment of MM and different lines of evidence suggest a close cross talk between these central cell-regulatory signaling networks. In this review, we outline the interplay between the UPS and mTOR pathways and discuss their implications for the pathophysiology and therapy of MM.
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28
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Zhang L, Li J, Lv X, Guo T, Li W, Zhang J. MID1-PP2A complex functions as new insights in human lung adenocarcinoma. J Cancer Res Clin Oncol 2018; 144:855-864. [PMID: 29450633 DOI: 10.1007/s00432-018-2601-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 02/02/2018] [Indexed: 12/15/2022]
Abstract
PURPOSE MID1 is an E3 ubiquitin ligase that was first found in Opitz G/BBB syndrome, but there has been little research into its role in lung diseases. We have found an accumulating evidence that indicates the MID1-PP2A complex plays a role in asthma and contributes to inflammation, but its roles in lung adenocarcinoma are unclear. This study aimed at evaluating the function of MID1-PP2A complex in human lung adenocarcinoma. METHODS We used western blot, ELISA and real-time quantitative PCR to detect the protein and mRNA levels of MID1 and PP2A in A549, H1975, and H1650 lung adenocarcinoma cell lines compared with the human bronchial epithelial cell line BEAS-2B. Additionally, we used IHC, ELISA and real-time quantitative PCR to dectect MID1 and PP2A levels in 30-paired lung adenocarcinoma tissues. We also detected apoptosis, proliferation and cell cycle-related protein expression after silencing MID1 and activing PP2A. RESULTS Our data show that MID1 was significantly upregulated in 30-paired lung adenocarcinoma tissues, and in A549, H1975 and H1650 cell lines compared with BEAS-2B. PP2A showed the opposite results. Furthermore, both upregulated MID1 and downregulated PP2A were correlated with age, but not sex, TNM stage or smoking history. In vitro experiments showed that PP2A was upregulated in lung adenocarcinoma cell lines that were transfected with MID1-siRNA, suggesting MID1 negatively regulates PP2A in lung adenocarcinoma. We also found that silencing MID1 expression or activating PP2A induced apoptosis, proliferation and cell cycle arrest. CONCLUSIONS We demonstrated that the MID1-PP2A complex plays an important role in lung adenocarcinoma, influencing cell cycle progression, proliferation and apoptosis. Our findings showed a novel molecular mechanism of lung tumorigenesis that may provide new insights for anti-tumor therapies.
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Affiliation(s)
- Lin Zhang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, 218 Ziqiang Street, Nanguan, Changchun, 130041, Jilin, People's Republic of China
| | - Junyao Li
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, 218 Ziqiang Street, Nanguan, Changchun, 130041, Jilin, People's Republic of China
| | - Xuejiao Lv
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, 218 Ziqiang Street, Nanguan, Changchun, 130041, Jilin, People's Republic of China
| | - Tingting Guo
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, 218 Ziqiang Street, Nanguan, Changchun, 130041, Jilin, People's Republic of China
| | - Wei Li
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, 218 Ziqiang Street, Nanguan, Changchun, 130041, Jilin, People's Republic of China
| | - Jie Zhang
- Department of Respiratory Medicine, The Second Affiliated Hospital of Jilin University, 218 Ziqiang Street, Nanguan, Changchun, 130041, Jilin, People's Republic of China.
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29
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Matthes F, Hettich MM, Schilling J, Flores-Dominguez D, Blank N, Wiglenda T, Buntru A, Wolf H, Weber S, Vorberg I, Dagane A, Dittmar G, Wanker E, Ehninger D, Krauss S. Inhibition of the MID1 protein complex: a novel approach targeting APP protein synthesis. Cell Death Discov 2018. [PMID: 29531801 PMCID: PMC5841321 DOI: 10.1038/s41420-017-0003-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Alzheimer’s disease (AD) is characterized by two neuropathological hallmarks: senile plaques, which are composed of amyloid-β (Aβ) peptides, and neurofibrillary tangles, which are composed of hyperphosphorylated tau protein. Aβ peptides are derived from sequential proteolytic cleavage of the amyloid precursor protein (APP). In this study, we identified a so far unknown mode of regulation of APP protein synthesis involving the MID1 protein complex: MID1 binds to and regulates the translation of APP mRNA. The underlying mode of action of MID1 involves the mTOR pathway. Thus, inhibition of the MID1 complex reduces the APP protein level in cultures of primary neurons. Based on this, we used one compound that we discovered previously to interfere with the MID1 complex, metformin, for in vivo experiments. Indeed, long-term treatment with metformin decreased APP protein expression levels and consequently Aβ in an AD mouse model. Importantly, we have initiated the metformin treatment late in life, at a time-point where mice were in an already progressed state of the disease, and could observe an improved behavioral phenotype. These findings together with our previous observation, showing that inhibition of the MID1 complex by metformin also decreases tau phosphorylation, make the MID1 complex a particularly interesting drug target for treating AD.
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Affiliation(s)
- Frank Matthes
- 1Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
| | - Moritz M Hettich
- 1Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
| | - Judith Schilling
- 1Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
| | | | - Nelli Blank
- 1Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
| | - Thomas Wiglenda
- 2Max Delbrueck Center for Molecular Medicine (MDC) Berlin-Buch, Berlin, Germany
| | - Alexander Buntru
- 2Max Delbrueck Center for Molecular Medicine (MDC) Berlin-Buch, Berlin, Germany
| | - Hanna Wolf
- 1Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
| | - Stephanie Weber
- 1Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
| | - Ina Vorberg
- 1Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
| | - Alina Dagane
- 2Max Delbrueck Center for Molecular Medicine (MDC) Berlin-Buch, Berlin, Germany
| | - Gunnar Dittmar
- 2Max Delbrueck Center for Molecular Medicine (MDC) Berlin-Buch, Berlin, Germany.,3Luxembourg Institute of Health, Strassen, Luxembourg
| | - Erich Wanker
- 2Max Delbrueck Center for Molecular Medicine (MDC) Berlin-Buch, Berlin, Germany
| | - Dan Ehninger
- 1Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
| | - Sybille Krauss
- 1Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Bonn, Germany
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30
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Kapur M, Monaghan CE, Ackerman SL. Regulation of mRNA Translation in Neurons-A Matter of Life and Death. Neuron 2017; 96:616-637. [PMID: 29096076 DOI: 10.1016/j.neuron.2017.09.057] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/20/2017] [Accepted: 09/28/2017] [Indexed: 12/14/2022]
Abstract
Dynamic regulation of mRNA translation initiation and elongation is essential for the survival and function of neural cells. Global reductions in translation initiation resulting from mutations in the translational machinery or inappropriate activation of the integrated stress response may contribute to pathogenesis in a subset of neurodegenerative disorders. Aberrant proteins generated by non-canonical translation initiation may be a factor in the neuron death observed in the nucleotide repeat expansion diseases. Dysfunction of central components of the elongation machinery, such as the tRNAs and their associated enzymes, can cause translational infidelity and ribosome stalling, resulting in neurodegeneration. Taken together, dysregulation of mRNA translation is emerging as a unifying mechanism underlying the pathogenesis of many neurodegenerative disorders.
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Affiliation(s)
- Mridu Kapur
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Caitlin E Monaghan
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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31
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Schweiger S, Matthes F, Posey K, Kickstein E, Weber S, Hettich MM, Pfurtscheller S, Ehninger D, Schneider R, Krauß S. Resveratrol induces dephosphorylation of Tau by interfering with the MID1-PP2A complex. Sci Rep 2017; 7:13753. [PMID: 29062069 PMCID: PMC5653760 DOI: 10.1038/s41598-017-12974-4] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 09/18/2017] [Indexed: 12/24/2022] Open
Abstract
The formation of paired helical filaments (PHF), which are composed of hyperphosphorylated Tau protein dissociating from microtubules, is one of the pathological hallmarks of Alzheimer's disease (AD) and other tauopathies. The most important phosphatase that is capable of dephosphorylating Tau at AD specific phospho-sites is protein phosphatase 2 A (PP2A). Here we show that resveratrol, a polyphenol, significantly induces PP2A activity and reduces Tau phosphorylation at PP2A-dependent epitopes. The increase in PP2A activity is caused by decreased expression of the MID1 ubiquitin ligase that mediates ubiquitin-specific modification and degradation of the catalytic subunit of PP2A when bound to microtubules. Interestingly, we further show that MID1 expression is elevated in AD tissue. Our data suggest a key role of MID1 in the pathology of AD and related tauopathies. Together with previous studies showing that resveratrol reduces β-amyloid toxicity they also give evidence of a promising role for resveratrol in the prophylaxis and therapy of AD.
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Affiliation(s)
- Susann Schweiger
- Institute for Human Genetics, University of Mainz, Langenbeckstr. 1, 55131, Mainz, Germany.
| | - Frank Matthes
- German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str.27, 53127, Bonn, Germany
| | - Karen Posey
- McGovern Medical School at University of Texas in Houston, Department of Pediatrics, 6431 Fannin Street, Houston, Texas, 77030, USA
| | - Eva Kickstein
- Max-Planck Institute for Molecular Genetics, Department of Human Molecular Genetics, Ihnestr. 73, 14195, Berlin, Germany
| | - Stephanie Weber
- German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str.27, 53127, Bonn, Germany
| | - Moritz M Hettich
- German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str.27, 53127, Bonn, Germany
| | - Sandra Pfurtscheller
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck (CMBI), Innrain 80/82, 6020, Innsbruck, Austria
| | - Dan Ehninger
- German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str.27, 53127, Bonn, Germany
| | - Rainer Schneider
- Institute of Biochemistry and Center for Molecular Biosciences Innsbruck (CMBI), Innrain 80/82, 6020, Innsbruck, Austria
| | - Sybille Krauß
- German Center for Neurodegenerative Diseases (DZNE), Sigmund-Freud-Str.27, 53127, Bonn, Germany.
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32
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Nakamura T, Ueyama T, Ninoyu Y, Sakaguchi H, Choijookhuu N, Hishikawa Y, Kiyonari H, Kohta M, Sakahara M, de Curtis I, Kohmura E, Hisa Y, Aiba A, Saito N. Novel role of Rac-Mid1 signaling in medial cerebellar development. Development 2017; 144:1863-1875. [PMID: 28512198 DOI: 10.1242/dev.147900] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/31/2017] [Indexed: 02/04/2023]
Abstract
Rac signaling impacts a relatively large number of downstream targets; however, few studies have established an association between Rac pathways and pathological conditions. In the present study, we generated mice with double knockout of Rac1 and Rac3 (Atoh1-Cre;Rac1flox/flox;Rac3-/- ) in cerebellar granule neurons (CGNs). We observed impaired tangential migration at E16.5, as well as numerous apoptotic CGNs at the deepest layer of the external granule layer (EGL) in the medial cerebellum of Atoh1-Cre;Rac1flox/flox;Rac3-/- mice at P8. Atoh1-Cre;Rac1flox/flox;Rac3-/- CGNs differentiated normally until expression of p27kip1 and NeuN in the deep EGL at P5. Primary CGNs and cerebellar microexplants from Atoh1-Cre;Rac1flox/flox;Rac3-/- mice exhibited impaired neuritogenesis, which was more apparent in Map2-positive dendrites. Such findings suggest that impaired tangential migration and final differentiation of CGNs have resulted in decreased cerebellum size and agenesis of the medial internal granule layer, respectively. Furthermore, Rac depleted/deleted cells exhibited decreased levels of Mid1 and impaired mTORC1 signaling. Mid1 depletion in CGNs produced mild impairments in neuritogenesis and reductions in mTORC1 signaling. Thus, a novel Rac-signaling pathway (Rac1-Mid1-mTORC1) may be involved in medial cerebellar development.
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Affiliation(s)
- Takashi Nakamura
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan.,Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Takehiko Ueyama
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Yuzuru Ninoyu
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
| | - Hirofumi Sakaguchi
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Narantsog Choijookhuu
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Yoshitaka Hishikawa
- Division of Histochemistry and Cell Biology, Department of Anatomy, Faculty of Medicine, University of Miyazaki, Miyazaki 889-1692, Japan
| | - Hiroshi Kiyonari
- Animal Resource Development Unit and Genetic Engineering Team, RIKEN Center for Life Science Technologies, Kobe 650-0047, Japan
| | - Masaaki Kohta
- Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Mizuho Sakahara
- Department of Molecular Genetics, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Ivan de Curtis
- Division of Neuroscience, San Raffaele Scientific Institute, Milano 20132, Italy
| | - Eiji Kohmura
- Department of Neurosurgery, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
| | - Yasuo Hisa
- Department of Otolaryngology-Head and Neck Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | - Atsu Aiba
- Department of Molecular Genetics, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan.,Laboratory of Animal Resources, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Naoaki Saito
- Laboratory of Molecular Pharmacology, Biosignal Research Center, Kobe University, Kobe 657-8501, Japan
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33
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Wright KM, Du H, Massiah MA. Structural and functional observations of the P151L MID1 mutation reveal alpha4 plays a significant role in X-linked Opitz Syndrome. FEBS J 2017; 284:2183-2193. [PMID: 28548391 DOI: 10.1111/febs.14121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 05/16/2017] [Accepted: 05/24/2017] [Indexed: 12/20/2022]
Abstract
Mutations of human MID1 are associated with X-linked Opitz G Syndrome (XLOS), which is characterized by midline birth defects. XLOS-observed mutations within the MID1 B-box1 domain are associated with cleft lip/palate, wide-spaced eyes and hyperspadias. Three of the four XLOS-observed mutations in the B-box1 domain results in unfolding but the structural and functional effects of the P151L mutation is not characterized. Here, we demonstrate that the P151L mutation does not disrupt the overall tertiary structure of the B-box1 domain and the adjacent domains. In fact, MID1 E3 ligase activity is slightly enhanced. However, the P151L mutation disrupted the ability of MID1 to catalyze the poly-ubiquitination of alpha4, a novel regulator of PP2A. This observation is consistent with results observed with the other three structure-destabilizing B-box1 mutations in targeting alpha4 but not PP2A. Alpha4 is shown to bind and sequester the catalytic subunit of PP2A and protect it from MID1-mediated ubiquitination and as a result, an increase in alpha4 can contribute to an increase in PP2A, playing a greater role in midline development during embryogenesis.
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Affiliation(s)
- Katharine M Wright
- Department of Chemistry and Center of Biomolecular Science, George Washington University, DC, USA
| | - Haijuan Du
- Department of Chemistry and Center of Biomolecular Science, George Washington University, DC, USA
| | - Michael A Massiah
- Department of Chemistry and Center of Biomolecular Science, George Washington University, DC, USA
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34
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Chen L, Wang K, Long A, Jia L, Zhang Y, Deng H, Li Y, Han J, Wang Y. Fasting-induced hormonal regulation of lysosomal function. Cell Res 2017; 27:748-763. [PMID: 28374748 PMCID: PMC5518872 DOI: 10.1038/cr.2017.45] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 02/19/2017] [Accepted: 02/24/2017] [Indexed: 12/14/2022] Open
Abstract
Lysosomes are centers for nutrient sensing and recycling that allow mammals to adapt to starvation. Regulation of lysosome dynamics by internal nutrient signaling is well described, but the mechanisms by which external cues modulate lysosomal function are unclear. Here, we describe an essential role of the fasting-induced hormone fibroblast growth factor 21 (FGF21) in lysosome homeostasis in mice. Fgf21 deficiency impairs hepatic lysosomal function by blocking transcription factor EB (TFEB), a master regulator of lysosome biogenesis and autophagy. FGF21 induces mobilization of calcium from the endoplasmic reticulum, which activates the transcriptional repressor downstream regulatory element antagonist modulator (DREAM), and thereby inhibits expression of Mid1 (encoding the E3 ligase Midline-1). Protein phosphatase PP2A, a substrate of MID1, accumulates and dephosphorylates TFEB, thereby upregulating genes involved in lysosome biogenesis, autophagy and lipid metabolism. Thus, an FGF21-TFEB signaling axis links lysosome homeostasis with extracellular hormonal signaling to orchestrate lipid metabolism during fasting.
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Affiliation(s)
- Liqun Chen
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Ke Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Aijun Long
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Liangjie Jia
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yuanyuan Zhang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yu Li
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Jinbo Han
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yiguo Wang
- MOE Key Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
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Lazarus MB, Levin RS, Shokat KM. Discovery of new substrates of the elongation factor-2 kinase suggests a broader role in the cellular nutrient response. Cell Signal 2016; 29:78-83. [PMID: 27760376 DOI: 10.1016/j.cellsig.2016.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 09/25/2016] [Accepted: 10/13/2016] [Indexed: 12/25/2022]
Abstract
Elongation Factor-2 Kinase (eEF2K) in an unusual mammalian enzyme that has one known substrate, elongation factor-2. It belongs to a class of kinases, called alpha kinases, that has little sequence identity to the >500 conventional protein kinases, but performs the same reaction and has similar catalytic residues. The phosphorylation of eEF2 blocks translation elongation, which is thought to be critical to regulating cellular energy usage. Here we report a system for discovering new substrates of alpha kinases and identify the first new substrates of eEF2K including AMPK and alpha4, and determine a sequence motif for the kinase that shows a requirement for threonine residues as the target of phosphorylation. These new substrates suggest that eEF2K has a more diverse role in regulating cellular energy usage that involves multiple pathways and regulatory feedback.
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Affiliation(s)
- Michael B Lazarus
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Rebecca S Levin
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Kevan M Shokat
- Howard Hughes Medical Institute and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA.
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Griesche N, Schilling J, Weber S, Rohm M, Pesch V, Matthes F, Auburger G, Krauss S. Regulation of mRNA Translation by MID1: A Common Mechanism of Expanded CAG Repeat RNAs. Front Cell Neurosci 2016; 10:226. [PMID: 27774050 PMCID: PMC5054010 DOI: 10.3389/fncel.2016.00226] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 09/20/2016] [Indexed: 12/28/2022] Open
Abstract
Expansion of CAG repeats, which code for the disease-causing polyglutamine protein, is a common feature in polyglutamine diseases. RNA-mediated mechanisms that contribute to neuropathology in polyglutamine diseases are important. RNA-toxicity describes a phenomenon by which the mutant CAG repeat RNA recruits RNA-binding proteins, thereby leading to aberrant function. For example the MID1 protein binds to mutant huntingtin (HTT) RNA, which is linked to Huntington's disease (HD), at its CAG repeat region and induces protein synthesis of mutant protein. But is this mechanism specific to HD or is it a common mechanism in CAG repeat expansion disorders? To answer this question, we have analyzed the interaction between MID1 and three other CAG repeat mRNAs, Ataxin2 (ATXN2), Ataxin3 (ATXN3), and Ataxin7 (ATXN7), that all differ in the sequence flanking the CAG repeat. We show that ATXN2, ATXN3, and ATXN7 bind to MID1 in a CAG repeat length-dependent manner. Furthermore, we show that functionally, in line with what we have previously observed for HTT, the binding of MID1 to ATXN2, ATXN3, and ATXN7 mRNA induces protein synthesis in a repeat length-dependent manner. Our data suggest that regulation of protein translation by the MID1 complex is a common mechanism for CAG repeat containing mRNAs.
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Affiliation(s)
| | | | | | - Marlena Rohm
- German Center for Neurodegenerative Diseases Bonn, Germany
| | - Verena Pesch
- German Center for Neurodegenerative Diseases Bonn, Germany
| | - Frank Matthes
- German Center for Neurodegenerative Diseases Bonn, Germany
| | - Georg Auburger
- Experimental Neurology, Goethe University Medical School Frankfurt, Germany
| | - Sybille Krauss
- German Center for Neurodegenerative Diseases Bonn, Germany
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37
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Pérez-Otaño I, Larsen RS, Wesseling JF. Emerging roles of GluN3-containing NMDA receptors in the CNS. Nat Rev Neurosci 2016; 17:623-35. [DOI: 10.1038/nrn.2016.92] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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38
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Abstract
Polyglutamine (polyQ) diseases are heritable dominant neurological disorders, caused by abnormal CAG tri-nucleotide expansion in the coding sequence of affected genes. Extension of CAG repeats results in the production of aberrant gene products that are deleterious to neurons, such as transcripts with a CAG stem-loop secondary structure, and proteins containing a long stretch of polyQ residues. Thus, determining methods for the prevention or elimination of these mutant gene products from neuronal cells and translating this knowledge to clinical application are currently important goals in the fields of neurology and neurogenetics. Recently, several studies have revealed intriguing findings related to the allele-selective regulation of CAG-expanded genes, and have proposed novel designs to selectively diminish the mutant polyQ proteins. In this review, we focus on the genes, genetically engineered proteins, and oligonucleotides that show potential to modulate the expression of mutant genes. We also discuss their respective molecular functions at the levels of transcription, translation, and post-translation.
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Affiliation(s)
- Chia-Rung Liu
- a Institute of Biochemistry and Molecular Biology, National Yang-Ming University , Taipei , Taiwan , Republic of China
| | - Tzu-Hao Cheng
- a Institute of Biochemistry and Molecular Biology, National Yang-Ming University , Taipei , Taiwan , Republic of China.,b Brain Research Center, National Yang-Ming University , Taipei , Taiwan , Republic of China
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Zhao Y, Zeng C, Massiah MA. Molecular dynamics simulation reveals insights into the mechanism of unfolding by the A130T/V mutations within the MID1 zinc-binding Bbox1 domain. PLoS One 2015; 10:e0124377. [PMID: 25874572 PMCID: PMC4395243 DOI: 10.1371/journal.pone.0124377] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 03/01/2015] [Indexed: 11/25/2022] Open
Abstract
The zinc-binding Bbox1 domain in protein MID1, a member of the TRIM family of proteins, facilitates the ubiquitination of the catalytic subunit of protein phosphatase 2A and alpha4, a protein regulator of PP2A. The natural mutation of residue A130 to a valine or threonine disrupts substrate recognition and catalysis. While NMR data revealed the A130T mutant Bbox1 domain failed to coordinate both structurally essential zinc ions and resulted in an unfolded structure, the unfolding mechanism is unknown. Principle component analysis revealed that residue A130 served as a hinge point between the structured β-strand-turn-β-strand (β-turn-β) and the lasso-like loop sub-structures that constitute loop1 of the ββα-RING fold that the Bbox1 domain adopts. Backbone RMSD data indicate significant flexibility and departure from the native structure within the first 5 ns of the molecular dynamics (MD) simulation for the A130V mutant (>6 Å) and after 30 ns for A130T mutant (>6 Å). Overall RMSF values were higher for the mutant structures and showed increased flexibility around residues 125 and 155, regions with zinc-coordinating residues. Simulated pKa values of the sulfhydryl group of C142 located near A130 suggested an increased in value to ~9.0, paralleling the increase in the apparent dielectric constants for the small cavity near residue A130. Protonation of the sulfhydryl group would disrupt zinc-coordination, directly contributing to unfolding of the Bbox1. Together, the increased motion of residues of loop 1, which contains four of the six zinc-binding cysteine residues, and the increased pKa of C142 could destabilize the structure of the zinc-coordinating residues and contribute to the unfolding.
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Affiliation(s)
- Yunjie Zhao
- Department of Physics, The George Washington University, Washington, District of Columbia, United States of America
| | - Chen Zeng
- Department of Physics, The George Washington University, Washington, District of Columbia, United States of America
- Department of Physics, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Michael A. Massiah
- Department of Chemistry, The George Washington University, Washington, District of Columbia, United States of America
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40
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Lee CW, Yang FC, Chang HY, Chou H, Tan BCM, Lee SC. Interaction between salt-inducible kinase 2 and protein phosphatase 2A regulates the activity of calcium/calmodulin-dependent protein kinase I and protein phosphatase methylesterase-1. J Biol Chem 2015; 289:21108-19. [PMID: 24841198 DOI: 10.1074/jbc.m113.540229] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Salt-inducible kinase 2 (SIK2) is the only AMP-activated kinase (AMPK) family member known to interact with protein phosphatase 2 (PP2A). However, the functional aspects of this complex are largely unknown. Here we report that the SIK2-PP2A complex preserves both kinase and phosphatase activities. In this capacity,SIK2 attenuates the association of the PP2A repressor, the protein phosphatase methylesterase-1 (PME-1), thus preserving the methylation status of the PP2A catalytic subunit. Furthermore, the SIK2-PP2A holoenzyme complex dephosphorylates and inactivates Ca2(+)/calmodulin-dependent protein kinase I (CaMKI), an upstream kinase for phosphorylating PME-1/Ser(15). The functionally antagonistic SIK2-PP2A and CaMKI and PME-1 networks thus constitute a negative feedback loop that modulates the phosphatase activity of PP2A. Depletion of SIK2 led to disruption of the SIK2-PP2A complex, activation of CaMKI, and downstream effects, including phosphorylation of HDAC5/Ser(259), sequestration of HDAC5 in the cytoplasm, and activation of myocyte-specific enhancer factor 2C (MEF2C)-mediated gene expression. These results suggest that the SIK2-PP2A complex functions in the regulation of MEF2C-dependent transcription. Furthermore, this study suggests that the tightly linked regulatory loop comprised of the SIK2-PP2A and CaMKI and PME-1 networks may function in fine-tuning cell proliferation and stress response.
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41
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Wright KM, Wu K, Babatunde O, Du H, Massiah MA. XLOS-observed mutations of MID1 Bbox1 domain cause domain unfolding. PLoS One 2014; 9:e107537. [PMID: 25216264 PMCID: PMC4162623 DOI: 10.1371/journal.pone.0107537] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Accepted: 08/20/2014] [Indexed: 12/13/2022] Open
Abstract
MID1 catalyzes the ubiquitination of the protein alpha4 and the catalytic subunit of protein phosphatase 2A. Mutations within the MID1 Bbox1 domain are associated with X-linked Opitz G syndrome (XLOS). Our functional assays have shown that mutations of Ala130 to Val or Thr, Cys142 to Ser and Cys145 to Thr completely disrupt the polyubiquitination of alpha4. Using NMR spectroscopy, we characterize the effect of these mutations on the tertiary structure of the Bbox1 domain by itself and in tandem with the Bbox2 domain. The mutation of either Cys142 or Cys145, each of which is involved in coordinating one of the two zinc ions, results in the collapse of signal dispersion in the HSQC spectrum of the Bbox1 domain indicating that the mutant protein structure is unfolded. Each mutation caused the coordination of both zinc ions, which are ∼ 13 Å apart, to be lost. Although Ala130 is not involved in the coordination of a zinc ion, the Ala130Thr mutant Bbox1 domain yields a poorly dispersed HSQC spectrum similar to those of the Cys142Ser and Cys145Thr mutants. Interestingly, neither cysteine mutation affects the structure of the adjacent Bbox2 domain when the two Bbox domains are engineered in their native tandem Bbox1-Bbox2 protein construct. Dynamic light scattering measurements suggest that the mutant Bbox1 domain has an increased propensity to form aggregates compared to the wild type Bbox1 domain. These studies provide insight into the mechanism by which mutations observed in XLOS affect the structure and function of the MID1 Bbox1 domain.
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Affiliation(s)
- Katharine M. Wright
- Department of Chemistry, George Washington University, Washington, D.C., United States of America
| | - Kuanlin Wu
- Department of Chemistry, George Washington University, Washington, D.C., United States of America
| | - Omotolani Babatunde
- Department of Chemistry, George Washington University, Washington, D.C., United States of America
| | - Haijuan Du
- Department of Chemistry, George Washington University, Washington, D.C., United States of America
| | - Michael A. Massiah
- Department of Chemistry, George Washington University, Washington, D.C., United States of America
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42
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Du H, Wu K, Didoronkute A, Levy MVA, Todi N, Shchelokova A, Massiah MA. MID1 catalyzes the ubiquitination of protein phosphatase 2A and mutations within its Bbox1 domain disrupt polyubiquitination of alpha4 but not of PP2Ac. PLoS One 2014; 9:e107428. [PMID: 25207814 PMCID: PMC4160256 DOI: 10.1371/journal.pone.0107428] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Accepted: 08/14/2014] [Indexed: 01/05/2023] Open
Abstract
MID1 is a microtubule-associated protein that belongs to the TRIM family. MID1 functions as an ubiquitin E3 ligase, and recently was shown to catalyze the polyubiquitination of, alpha4, a protein regulator of protein phosphatase 2A (PP2A). It has been hypothesized that MID1 regulates PP2A, requiring the intermediary interaction with alpha4. Here we report that MID1 catalyzes the in vitro ubiquitination of the catalytic subunit of PP2A (PP2Ac) in the absence of alpha4. In the presence of alpha4, the level of PP2Ac ubiquitination is reduced. Using the MID1 RING-Bbox1-Bbox2 (RB1B2) construct containing the E3 ligase domains, we investigate the functional effects of mutations within the Bbox domains that are identified in patients with X-linked Opitz G syndrome (XLOS). The RB1B2 proteins harboring the C142S, C145T, A130V/T mutations within the Bbox1 domain and C195F mutation within the Bbox2 domain maintain auto-polyubiquitination activity. Qualitatively, the RB1B2 proteins containing these mutations are able to catalyze the ubiquitination of PP2Ac. In contrast, the RB1B2 proteins with mutations within the Bbox1 domain are unable to catalyze the polyubiquitination of alpha4. These results suggest that unregulated alpha4 may be the direct consequence of these natural mutations in the Bbox1 domain of MID1, and hence alpha4 could play a greater role to account for the increased amount of PP2A observed in XLOS-derived fibroblasts.
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Affiliation(s)
- Haijuan Du
- Department of Chemistry, George Washington University, Washington, District of Columbia, United States of America
| | - Kuanlin Wu
- Department of Chemistry, George Washington University, Washington, District of Columbia, United States of America
| | - Alma Didoronkute
- Department of Chemistry, George Washington University, Washington, District of Columbia, United States of America
| | - Marcus V. A. Levy
- Department of Chemistry, George Washington University, Washington, District of Columbia, United States of America
| | - Nimish Todi
- Department of Chemistry, George Washington University, Washington, District of Columbia, United States of America
| | - Anna Shchelokova
- Department of Chemistry, George Washington University, Washington, District of Columbia, United States of America
| | - Michael A. Massiah
- Department of Chemistry, George Washington University, Washington, District of Columbia, United States of America
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43
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Boding L, Hansen AK, Meroni G, Johansen BB, Braunstein TH, Bonefeld CM, Kongsbak M, Jensen BAH, Woetmann A, Thomsen AR, Ødum N, von Essen MR, Geisler C. Midline 1 directs lytic granule exocytosis and cytotoxicity of mouse killer T cells. Eur J Immunol 2014; 44:3109-18. [DOI: 10.1002/eji.201344388] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 05/27/2014] [Accepted: 07/08/2014] [Indexed: 11/07/2022]
Affiliation(s)
- Lasse Boding
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Ann K. Hansen
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Germana Meroni
- Institute for Maternal and Child Health - IRCCS “Burlo Garofolo”; Trieste Italy
| | - Bo B. Johansen
- Core Facility for Integrated Microscopy; University of Copenhagen; Copenhagen Denmark
| | - Thomas H. Braunstein
- Department of Biomedical Sciences; Danish National Research Foundation Centre for Cardiac Arrhythmia; University of Copenhagen; Copenhagen Denmark
| | - Charlotte M. Bonefeld
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Martin Kongsbak
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Benjamin A. H. Jensen
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Anders Woetmann
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Allan R. Thomsen
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Niels Ødum
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Marina R. von Essen
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
| | - Carsten Geisler
- Department of International Health, Immunology and Microbiology; University of Copenhagen; Copenhagen Denmark
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Hettich MM, Matthes F, Ryan DP, Griesche N, Schröder S, Dorn S, Krauß S, Ehninger D. The anti-diabetic drug metformin reduces BACE1 protein level by interfering with the MID1 complex. PLoS One 2014; 9:e102420. [PMID: 25025689 PMCID: PMC4099345 DOI: 10.1371/journal.pone.0102420] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 06/18/2014] [Indexed: 01/21/2023] Open
Abstract
Alzheimer's disease (AD), the most common form of dementia in the elderly, is characterized by two neuropathological hallmarks: senile plaques, which are composed of Aβ peptides, and neurofibrillary tangles, which are composed of hyperphosphorylated TAU protein. Diabetic patients with dysregulated insulin signalling are at increased risk of developing AD. Further, several animal models of diabetes show increased Aβ expression and hyperphosphorylated tau. As we have shown recently, the anti-diabetic drug metformin is capable of dephosphorylating tau at AD-relevant phospho-sites. Here, we investigated the effect of metformin on the main amyloidogenic enzyme BACE1 and, thus, on the production of Aβ peptides, the second pathological hallmark of AD. We find similar results in cultures of primary neurons, a human cell line model of AD and in vivo in mice. We show that treatment with metformin decreases BACE1 protein expression by interfering with an mRNA-protein complex that contains the ubiquitin ligase MID1, thereby reducing BACE1 activity. Together with our previous findings these results indicate that metformin may target both pathological hallmarks of AD and may be of therapeutic value for treating and/or preventing AD.
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Affiliation(s)
- Moritz M. Hettich
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE), Bonn, Germany
| | - Frank Matthes
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE), Bonn, Germany
| | - Devon P. Ryan
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE), Bonn, Germany
| | - Nadine Griesche
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE), Bonn, Germany
| | - Susanne Schröder
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE), Bonn, Germany
| | - Stephanie Dorn
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE), Bonn, Germany
| | - Sybille Krauß
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE), Bonn, Germany
| | - Dan Ehninger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE), Bonn, Germany
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45
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Köhler A, Demir Ü, Kickstein E, Krauss S, Aigner J, Aranda-Orgillés B, Karagiannidis AI, Achmüller C, Bu H, Wunderlich A, Schweiger MR, Schaefer G, Schweiger S, Klocker H, Schneider R. A hormone-dependent feedback-loop controls androgen receptor levels by limiting MID1, a novel translation enhancer and promoter of oncogenic signaling. Mol Cancer 2014; 13:146. [PMID: 24913494 PMCID: PMC4074869 DOI: 10.1186/1476-4598-13-146] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 05/30/2014] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND High androgen receptor (AR) level in primary tumour predicts increased prostate cancer (PCa)-specific mortality. Furthermore, activations of the AR, PI3K, mTOR, NFκB and Hedgehog (Hh) signaling pathways are involved in the fatal development of castration-resistant prostate cancer during androgen ablation therapy. MID1, a negative regulator of the tumor-suppressor PP2A, is known to promote PI3K, mTOR, NFκB and Hh signaling. Here we investigate the interaction of MID1 and AR. METHODS AR and MID1 mRNA and protein levels were measured by qPCR, Western blot and immunohistochemistry. Co-immunoprecipitation followed by PCR and RNA-pull-down followed by Western blot was used to investigate protein-mRNA interaction, chromatin-immunoprecipitation followed by next-generation sequencing for identification of AR chromatin binding sites. AR transcriptional activity and activity of promoter binding sites for AR were analyzed by reporter gene assays. For knockdown or overexpression of proteins of interest prostate cancer cells were transfected with siRNA or expression plasmids, respectively. RESULTS The microtubule-associated MID1 protein complex associates with AR mRNA via purine-rich trinucleotide repeats, expansions of which are known to correlate with ataxia and cancer. The level of MID1 directly correlates with the AR protein level in PCa cells. Overexpression of MID1 results in a several fold increase in AR protein and activity without major changes in mRNA-levels, whereas siRNA-triggered knockdown of MID1 mRNA reduces AR-protein levels significantly. Upregulation of AR protein by MID1 occurs via increased translation as no major changes in AR protein stability could be observed. AR on the other hand, regulates MID1 via several functional AR binding sites in the MID1 gene, and, in the presence of androgens, exerts a negative feedback loop on MID1 transcription. Thus, androgen withdrawal increases MID1 and concomitantly AR-protein levels. In line with this, MID1 is significantly over-expressed in PCa in a stage-dependent manner. CONCLUSION Promotion of AR, in addition to enhancement of the Akt-, NFκB-, and Hh-pathways by sustained MID1-upregulation during androgen deprivation therapy provides a powerful proliferative scenario for PCa progression into castration resistance. Thus MID1 represents a novel, multi-faceted player in PCa and a promising target to treat castration resistant prostate cancer.
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Affiliation(s)
- Andrea Köhler
- Institute of Biochemistry, Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Ümmühan Demir
- Department of Urology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Eva Kickstein
- Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Sybille Krauss
- Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
- Present address: German Center for Neurodegenerative Diseases (DZNE), Biomedical Center (BMZ1), Building 344, 53127 Bonn, Germany
| | - Johanna Aigner
- Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | | | - Antonios I Karagiannidis
- Institute of Biochemistry, Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Clemens Achmüller
- Institute of Biochemistry, Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Huajie Bu
- Department of Urology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Andrea Wunderlich
- Institute of Vertebrate Genetics, Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Michal-Ruth Schweiger
- Institute of Vertebrate Genetics, Max-Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Georg Schaefer
- Department of Urology, Innsbruck Medical University, 6020 Innsbruck, Austria
- Department of Pathology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Susann Schweiger
- Universitätsmedizin Mainz, Institute for Human Genetics, 55131 Mainz, Germany
- Division of Medical Sciences, Medical School, DD1 9SY Dundee, UK
| | - Helmut Klocker
- Department of Urology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Rainer Schneider
- Institute of Biochemistry, Center of Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
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Metformin lowers Ser-129 phosphorylated α-synuclein levels via mTOR-dependent protein phosphatase 2A activation. Cell Death Dis 2014; 5:e1209. [PMID: 24810045 PMCID: PMC4047877 DOI: 10.1038/cddis.2014.175] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Revised: 03/10/2014] [Accepted: 03/17/2014] [Indexed: 01/08/2023]
Abstract
Phospho-Ser129 α-synuclein is the modified form of α-synuclein that occurs most frequently within Parkinson's disease pathological inclusions. Here we demonstrate that the antidiabetic drug metformin significantly reduces levels of phospho-Ser129 α-synuclein and the ratio of phospho-Ser129 α-synuclein to total α-synuclein. This effect was documented in vitro in SH-SY5Y and HeLa cells as well as in primary cultures of hippocampal neurons. In vitro work also elucidated the mechanisms underlying metformin's action. Following metformin exposure, decreased phospho-Ser129 α-synuclein was not strictly dependent on induction of AMP-activated protein kinase, a primary target of the drug. On the other hand, metformin-induced phospho-Ser129 α-synuclein reduction was consistently associated with inhibition of mammalian target of rapamycin (mTOR) and activation of protein phosphatase 2A (PP2A). Evidence supporting a key role of mTOR/PP2A signaling included the finding that, similar to metformin, the canonical mTOR inhibitor rapamycin was capable of lowering the ratio of phospho-Ser129 α-synuclein to total α-synuclein. Furthermore, no decrease in phosphorylated α-synuclein occurred with either metformin or rapamycin when phosphatase activity was inhibited, supporting a direct relationship between mTOR inhibition, PP2A activation and protein dephosphorylation. A final set of experiments confirmed the effectiveness of metformin in vivo in wild-type C57BL/6 mice. Addition of the drug to food or drinking water lowered levels of phospho-Ser129 α-synuclein in the brain of treated animals. These data reveal a new mechanism leading to α-synuclein dephosphorylation that could be targeted for therapeutic intervention by drugs like metformin and rapamycin.
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Varadkar P, Despres D, Kraman M, Lozier J, Phadke A, Nagaraju K, Mccright B. The protein phosphatase 2A B56γ regulatory subunit is required for heart development. Dev Dyn 2014; 243:778-90. [PMID: 24425002 DOI: 10.1002/dvdy.24111] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 12/16/2013] [Accepted: 12/19/2013] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Protein Phosphatase 2A (PP2A) function is controlled by regulatory subunits that modulate the activity of the catalytic subunit and direct the PP2A complex to specific intracellular locations. To study PP2A's role in signal transduction pathways that control growth and differentiation in vivo, a transgenic mouse lacking the B56γ regulatory subunit of PP2A was made. RESULTS Lack of PP2A activity specific to the PP2A-B56γ holoenzyme, resulted in the formation of an incomplete ventricular septum and a decrease in the number of ventricular cardiomyocytes. During cardiac development, B56γ is expressed in the nucleus of α-actinin-positive cardiomyocytes that contain Z-bands. The pattern of B56γ expression correlated with the cardiomyocyte apoptosis we observed in B56γ-deficient mice during mid to late gestation. In addition to the cardiac phenotypes, mice lacking B56γ have a decrease in locomotive coordination and gripping strength, indicating that B56γ has a role in controlling PP2A activity required for efficient neuromuscular function. CONCLUSIONS PP2A-B56γ activity is required for efficient cardiomyocyte maturation and survival. The PP2A B56γ regulatory subunit controls PP2A substrate specificity in vivo in a manner that cannot be fully compensated for by other B56 subunits.
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Affiliation(s)
- Prajakta Varadkar
- Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, FDA, Bethesda, Maryland
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McDonald WJ, Thomas LN, Koirala S, Too CKL. Progestin-inducible EDD E3 ubiquitin ligase binds to α4 phosphoprotein to regulate ubiquitination and degradation of protein phosphatase PP2Ac. Mol Cell Endocrinol 2014; 382:254-261. [PMID: 24145130 DOI: 10.1016/j.mce.2013.09.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/20/2013] [Accepted: 09/26/2013] [Indexed: 10/26/2022]
Abstract
Mammalian α4 phosphoprotein binds to the protein phosphatase 2A catalytic subunit (PP2Ac) to regulate PP2A activity, and to poly(A)-binding protein (PABP) and progestin-inducible EDD E3 ubiquitin ligase. This study showed induction of the EDD protein by progesterone, 17β-estradiol and prolactin in breast cancer cells. Co-immunoprecipitation analyses, using lysates of COS-1 cells transfected with α4-deletion constructs, showed the α4 N-terminus binding to endogenous PP2Ac and PABP, and the C-terminus to EDD. Monoubiquitinated α4 in MCF-7 cells was unaffected by EDD-targeting siRNA (siEDD) nor by non-targetting siNT, thus, EDD does not ubiquitinate α4. PP2Ac is polyubiquitinated, and 36-kDa PP2Ac only was detected in siEDD- or siNT-transfected cells. However, treatment with proteasomal inhibitor MG132 showed polyubiquitinated-PP2Ac molecules (∼65-250kDa) abundantly in siNT controls but low in siEDD-transfectants, implicating PP2Ac as an EDD substrate. Finally, progesterone induction of EDD in MCF-7 cells correlated with decreased PP2Ac levels, further implicating hormone-inducible EDD in PP2Ac turnover.
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Affiliation(s)
- William J McDonald
- Department of Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Lynn N Thomas
- Department of Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Samir Koirala
- Department of Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Catherine K L Too
- Department of Biochemistry & Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Department of Obstetrics & Gynaecology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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X-linked microtubule-associated protein, Mid1, regulates axon development. Proc Natl Acad Sci U S A 2013; 110:19131-6. [PMID: 24194544 DOI: 10.1073/pnas.1303687110] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Opitz syndrome (OS) is a genetic neurological disorder. The gene responsible for the X-linked form of OS, Midline-1 (MID1), encodes an E3 ubiquitin ligase that regulates the degradation of the catalytic subunit of protein phosphatase 2A (PP2Ac). However, how Mid1 functions during neural development is largely unknown. In this study, we provide data from in vitro and in vivo experiments suggesting that silencing Mid1 in developing neurons promotes axon growth and branch formation, resulting in a disruption of callosal axon projections in the contralateral cortex. In addition, a similar phenotype of axonal development was observed in the Mid1 knockout mouse. This defect was largely due to the accumulation of PP2Ac in Mid1-depleted cells as further down-regulation of PP2Ac rescued the axonal phenotype. Together, these data demonstrate that Mid1-dependent PP2Ac turnover is important for normal axonal development and that dysregulation of this process may contribute to the underlying cause of OS.
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Mechanisms of RNA-induced toxicity in CAG repeat disorders. Cell Death Dis 2013; 4:e752. [PMID: 23907466 PMCID: PMC3763438 DOI: 10.1038/cddis.2013.276] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 06/21/2013] [Accepted: 06/28/2013] [Indexed: 01/27/2023]
Abstract
Several inherited neurodegenerative disorders are caused by CAG trinucleotide repeat expansions, which can be located either in the coding region or in the untranslated region (UTR) of the respective genes. Polyglutamine diseases (polyQ diseases) are caused by an expansion of a stretch of CAG repeats within the coding region, translating into a polyQ tract. The polyQ tract expansions result in conformational changes, eventually leading to aggregate formation. It is widely believed that the aggregation of polyQ proteins is linked with disease development. In addition, in the last couple of years, it has been shown that RNA-mediated mechanisms also have a profound role in neurotoxicity in both polyQ diseases and diseases caused by elongated CAG repeat motifs in their UTRs. Here, we review the different molecular mechanisms assigned to mRNAs with expanded CAG repeats. One aspect is the mRNA folding of CAG repeats. Furthermore, pathogenic mechanisms assigned to CAG repeat mRNAs are discussed. First, we discuss mechanisms that involve the sequestration of the diverse proteins to the expanded CAG repeat mRNA molecules. As a result of this, several cellular mechanisms are aberrantly regulated. These include the sequestration of MBNL1, leading to misregulated splicing; sequestration of nucleolin, leading to reduced cellular rRNA; and sequestration of proteins of the siRNA machinery, resulting in the production of short silencing RNAs that affect gene expression. Second, we discuss the effect of expanded CAG repeats on the subcellular localization, transcription and translation of the CAG repeat mRNA itself. Here we focus on the MID1 protein complex that triggers an increased translation of expanded CAG repeat mRNAs and a mechanism called repeat-associated non-ATG translation, which leads to proteins aberrantly translated from CAG repeat mRNAs. In addition, therapeutic approaches for CAG repeat disorders are discussed. Together, all the findings summarized here show that mutant mRNA has a fundamental role in the pathogenesis of CAG repeat diseases.
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