1
|
Shoob S, Buchbinder N, Shinikamin O, Gold O, Baeloha H, Langberg T, Zarhin D, Shapira I, Braun G, Habib N, Slutsky I. Deep brain stimulation of thalamic nucleus reuniens promotes neuronal and cognitive resilience in an Alzheimer's disease mouse model. Nat Commun 2023; 14:7002. [PMID: 37919286 PMCID: PMC10622498 DOI: 10.1038/s41467-023-42721-5] [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: 10/15/2022] [Accepted: 10/19/2023] [Indexed: 11/04/2023] Open
Abstract
The mechanisms that confer cognitive resilience to Alzheimer's Disease (AD) are not fully understood. Here, we describe a neural circuit mechanism underlying this resilience in a familial AD mouse model. In the prodromal disease stage, interictal epileptiform spikes (IESs) emerge during anesthesia in the CA1 and mPFC regions, leading to working memory disruptions. These IESs are driven by inputs from the thalamic nucleus reuniens (nRE). Indeed, tonic deep brain stimulation of the nRE (tDBS-nRE) effectively suppresses IESs and restores firing rate homeostasis under anesthesia, preventing further impairments in nRE-CA1 synaptic facilitation and working memory. Notably, applying tDBS-nRE during the prodromal phase in young APP/PS1 mice mitigates age-dependent memory decline. The IES rate during anesthesia in young APP/PS1 mice correlates with later working memory impairments. These findings highlight the nRE as a central hub of functional resilience and underscore the clinical promise of DBS in conferring resilience to AD pathology by restoring circuit-level homeostasis.
Collapse
Affiliation(s)
- Shiri Shoob
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Nadav Buchbinder
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Ortal Shinikamin
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Or Gold
- Edmond & Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Halit Baeloha
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Tomer Langberg
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Daniel Zarhin
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Ilana Shapira
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Gabriella Braun
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Naomi Habib
- Edmond & Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Inna Slutsky
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel.
- Sagol School of Neuroscience, Tel Aviv University, 69978, Tel Aviv, Israel.
| |
Collapse
|
2
|
Nikom D, Zheng S. Alternative splicing in neurodegenerative disease and the promise of RNA therapies. Nat Rev Neurosci 2023; 24:457-473. [PMID: 37336982 DOI: 10.1038/s41583-023-00717-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2023] [Indexed: 06/21/2023]
Abstract
Alternative splicing generates a myriad of RNA products and protein isoforms of different functions from a single gene. Dysregulated alternative splicing has emerged as a new mechanism broadly implicated in the pathogenesis of neurodegenerative diseases such as Alzheimer disease, amyotrophic lateral sclerosis, frontotemporal dementia, Parkinson disease and repeat expansion diseases. Understanding the mechanisms and functional outcomes of abnormal splicing in neurological disorders is vital in developing effective therapies to treat mis-splicing pathology. In this Review, we discuss emerging research and evidence of the roles of alternative splicing defects in major neurodegenerative diseases and summarize the latest advances in RNA-based therapeutic strategies to target these disorders.
Collapse
Affiliation(s)
- David Nikom
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, USA
- Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA, USA
| | - Sika Zheng
- Neuroscience Graduate Program, University of California, Riverside, Riverside, CA, USA.
- Center for RNA Biology and Medicine, University of California, Riverside, Riverside, CA, USA.
- Division of Biomedical Sciences, University of California, Riverside, Riverside, CA, USA.
| |
Collapse
|
3
|
Cun Y, An S, Zheng H, Lan J, Chen W, Luo W, Yao C, Li X, Huang X, Sun X, Wu Z, Hu Y, Li Z, Zhang S, Wu G, Yang M, Tang M, Yu R, Liao X, Gao G, Zhao W, Wang J, Li J. Specific Regulation of m 6A by SRSF7 Promotes the Progression of Glioblastoma. GENOMICS, PROTEOMICS & BIOINFORMATICS 2023; 21:707-728. [PMID: 34954129 PMCID: PMC10787126 DOI: 10.1016/j.gpb.2021.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 11/06/2021] [Accepted: 12/14/2021] [Indexed: 02/07/2023]
Abstract
Serine/arginine-rich splicing factor 7 (SRSF7), a known splicing factor, has been revealed to play oncogenic roles in multiple cancers. However, the mechanisms underlying its oncogenic roles have not been well addressed. Here, based on N6-methyladenosine (m6A) co-methylation network analysis across diverse cell lines, we find that the gene expression of SRSF7 is positively correlated with glioblastoma (GBM) cell-specific m6A methylation. We then indicate that SRSF7 is a novel m6A regulator, which specifically facilitates the m6A methylation near its binding sites on the mRNAs involved in cell proliferation and migration, through recruiting the methyltransferase complex. Moreover, SRSF7 promotes the proliferation and migration of GBM cells largely dependent on the presence of the m6A methyltransferase. The two m6A sites on the mRNA for PDZ-binding kinase (PBK) are regulated by SRSF7 and partially mediate the effects of SRSF7 in GBM cells through recognition by insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). Together, our discovery reveals a novel role of SRSF7 in regulating m6A and validates the presence and functional importance of temporal- and spatial-specific regulation of m6A mediated by RNA-binding proteins (RBPs).
Collapse
Affiliation(s)
- Yixian Cun
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Sanqi An
- Department of Medical Informatics, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China; Biosafety Level-3 Laboratory, Life Sciences Institute, Guangxi Medical University, Nanning 530020, China
| | - Haiqing Zheng
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Jing Lan
- Department of Obstetrics and Gynecology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Wenfang Chen
- Department of Medical Informatics, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Wanjun Luo
- Department of Obstetrics and Gynecology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China
| | - Chengguo Yao
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Xincheng Li
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Xiang Huang
- Department of Medical Informatics, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Xiang Sun
- Department of Medical Informatics, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Zehong Wu
- Department of Medical Informatics, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Yameng Hu
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Ziwen Li
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Shuxia Zhang
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Geyan Wu
- State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-sen University, Guangzhou 510080, China
| | - Meisongzhu Yang
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Miaoling Tang
- State Key Laboratory of Oncology in South China, Cancer Center, Sun Yat-sen University, Guangzhou 510080, China
| | - Ruyuan Yu
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Xinyi Liao
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Guicheng Gao
- Department of Medical Informatics, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Wei Zhao
- Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China
| | - Jinkai Wang
- Department of Medical Informatics, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China; Center for Stem Cell Biology and Tissue Engineering, Key Laboratory for Stem Cells and Tissue Engineering, Ministry of Education, Sun Yat-sen University, Guangzhou 510080, China; RNA Biomedical Institute, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou 510080, China.
| | - Jun Li
- Department of Rehabilitation Medicine, Key Laboratory of Liver Disease of Guangdong Province, The Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China; Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.
| |
Collapse
|
4
|
Kumar J, Lackey L, Waldern JM, Dey A, Mustoe AM, Weeks KM, Mathews DH, Laederach A. Quantitative prediction of variant effects on alternative splicing in MAPT using endogenous pre-messenger RNA structure probing. eLife 2022; 11:73888. [PMID: 35695373 PMCID: PMC9236610 DOI: 10.7554/elife.73888] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 06/12/2022] [Indexed: 11/29/2022] Open
Abstract
Splicing is highly regulated and is modulated by numerous factors. Quantitative predictions for how a mutation will affect precursor mRNA (pre-mRNA) structure and downstream function are particularly challenging. Here, we use a novel chemical probing strategy to visualize endogenous precursor and mature MAPT mRNA structures in cells. We used these data to estimate Boltzmann suboptimal structural ensembles, which were then analyzed to predict consequences of mutations on pre-mRNA structure. Further analysis of recent cryo-EM structures of the spliceosome at different stages of the splicing cycle revealed that the footprint of the Bact complex with pre-mRNA best predicted alternative splicing outcomes for exon 10 inclusion of the alternatively spliced MAPT gene, achieving 74% accuracy. We further developed a β-regression weighting framework that incorporates splice site strength, RNA structure, and exonic/intronic splicing regulatory elements capable of predicting, with 90% accuracy, the effects of 47 known and 6 newly discovered mutations on inclusion of exon 10 of MAPT. This combined experimental and computational framework represents a path forward for accurate prediction of splicing-related disease-causing variants.
Collapse
Affiliation(s)
- Jayashree Kumar
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Lela Lackey
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Department of Genetics and Biochemistry, Center for Human Genetics, Clemson University, Greenwood, United States
| | - Justin M Waldern
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Abhishek Dey
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - Anthony M Mustoe
- Verna and Marrs McClean Department of Biochemistry and Molecular Biology, Therapeutic Innovation Center (THINC), and Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Kevin M Weeks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, United States
| | - David H Mathews
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, United States
| | - Alain Laederach
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States.,Curriculum in Bioinformatics and Computational Biology, University of North Carolina at Chapel Hill, Chapel Hill, United States
| |
Collapse
|
5
|
Jutzi D, Ruepp MD. Alternative Splicing in Human Biology and Disease. Methods Mol Biol 2022; 2537:1-19. [PMID: 35895255 DOI: 10.1007/978-1-0716-2521-7_1] [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] [Indexed: 06/15/2023]
Abstract
Alternative pre-mRNA splicing allows for the production of multiple mRNAs from an individual gene, which not only expands the protein-coding potential of the genome but also enables complex mechanisms for the post-transcriptional control of gene expression. Regulation of alternative splicing entails a combinatorial interplay between an abundance of trans-acting splicing factors, cis-acting regulatory sequence elements and their concerted effects on the core splicing machinery. Given the extent and biological significance of alternative splicing in humans, it is not surprising that aberrant splicing patterns can cause or contribute to a wide range of diseases. In this introductory chapter, we outline the mechanisms that govern alternative pre-mRNA splicing and its regulation and discuss how dysregulated splicing contributes to human diseases affecting the motor system and the brain.
Collapse
Affiliation(s)
- Daniel Jutzi
- United Kingdom Dementia Research Institute Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, UK.
| | - Marc-David Ruepp
- United Kingdom Dementia Research Institute Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, UK.
| |
Collapse
|
6
|
Xing S, Wang J, Wu R, Hefti MM, Crary JF, Lu Y. Identification of HnRNPC as a novel Tau exon 10 splicing factor using RNA antisense purification mass spectrometry. RNA Biol 2021; 19:104-116. [PMID: 34965173 PMCID: PMC8786334 DOI: 10.1080/15476286.2021.2015175] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Alternative splicing in Tau exon 10 generates 3 R- and 4 R-Tau proteoforms, which have equal abundance in healthy adult human brain. Aberrant alternative splicing in Tau exon 10 leads to distortion of the balanced 3 R- and 4 R-Tau expression levels, which is a causal factor to trigger toxic Tau aggregation, neuron dysfunction and patient death in a group of neurodegenerative diseases known as tauopathies. Hence, identification of regulators upstream of the Tau exon 10 splicing events are crucial to understanding pathogenic mechanisms driving tauopathies. In this study, we used RNA Antisense Purification with Mass Spectrometry (RAP-MS) analysis to identify RNA-binding proteins (RBPs) that interact with the Tau pre-mRNA near exon 10. Among the newly identified RBP candidates, we show that knockdown of hnRNPC induces Tau exon 10 skipping whereas overexpression of hnRNPC promotes Tau exon 10 inclusion. In addition, we show that hnRNPC interacts with the poly-uridine (U-tract) sequences in introns 9 and 10 of Tau pre-mRNA. Mutation of these U-tract motifs abolished binding of hnRNPC with Tau pre-mRNA fragment and blocked its impact on Tau exon 10 inclusion. These findings indicate that hnRNPC binds and utilizes these U-tract motifs located in introns 9 and 10 of Tau pre-mRNA to promote Tau exon 10 inclusion. Intriguingly, high hnRNPC expression level is associated with progressive supranuclear palsy (PSP), a sporadic tauopathy with pathological accumulation of Tau species that contain exon 10, which suggests a putative therapeutic role of hnRNPC for PSP treatment.
![]() ![]()
Collapse
Affiliation(s)
- Sansi Xing
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| | - Jane Wang
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Ruilin Wu
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada
| | - Marco M. Hefti
- Department of Pathology, University of Iowa, Iowa City, IA, USA
| | - John F. Crary
- Department of Pathology and Department of Neuroscience, Neuropathology Brain Bank & Research Core, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Yu Lu
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| |
Collapse
|
7
|
Ashok C, Ahuja N, Natua S, Mishra J, Samaiya A, Shukla S. E2F1 and epigenetic modifiers orchestrate breast cancer progression by regulating oxygen-dependent ESRP1 expression. Oncogenesis 2021; 10:58. [PMID: 34362878 PMCID: PMC8346533 DOI: 10.1038/s41389-021-00347-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 07/16/2021] [Accepted: 07/26/2021] [Indexed: 02/07/2023] Open
Abstract
Epithelial splicing regulatory protein 1 (ESRP1) is an RNA binding protein that governs the alternative splicing events related to epithelial phenotypes. ESRP1 contributes significantly at different stages of cancer progression. ESRP1 expression is substantially elevated in carcinoma in situ compared to the normal epithelium, whereas it is drastically ablated in cancer cells within hypoxic niches, which promotes epithelial to mesenchymal transition (EMT). Although a considerable body of research sought to understand the EMT-associated ESRP1 downregulation, the regulatory mechanisms underlying ESRP1 upregulation in primary tumors remained largely uncharted. This study seeks to unveil the regulatory mechanisms that spatiotemporally fine-tune the ESRP1 expression during breast carcinogenesis. Our results reveal that an elevated expression of transcription factor E2F1 and increased CpG hydroxymethylation of the E2F1 binding motif conjointly induce ESRP1 expression in breast carcinoma. However, E2F1 fails to upregulate ESRP1 despite its abundance in oxygen-deprived breast cancer cells. Mechanistically, impelled by the hypoxia-driven reduction of tet methylcytosine dioxygenase 3 (TET3) activity, CpG sites across the E2F1 binding motif lose the hydroxymethylation marks while gaining the de novo methyltransferase-elicited methylation marks. These two oxygen-sensitive epigenetic events work in concert to repel E2F1 from the ESRP1 promoter, thereby diminishing ESRP1 expression under hypoxia. Furthermore, E2F1 skews the cancer spliceome by upregulating splicing factor SRSF7 in hypoxic breast cancer cells. Our findings provide previously unreported mechanistic insights into the plastic nature of ESRP1 expression and insinuate important implications in therapeutics targeting breast cancer progression.
Collapse
Affiliation(s)
- Cheemala Ashok
- grid.462376.20000 0004 1763 8131Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh India
| | - Neha Ahuja
- grid.462376.20000 0004 1763 8131Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh India
| | - Subhashis Natua
- grid.462376.20000 0004 1763 8131Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh India
| | - Jharna Mishra
- Department of Pathology, Bansal Hospital, Bhopal, Madhya Pradesh India
| | - Atul Samaiya
- Department of Surgical Oncology, Bansal Hospital, Bhopal, Madhya Pradesh India
| | - Sanjeev Shukla
- grid.462376.20000 0004 1763 8131Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, Madhya Pradesh India
| |
Collapse
|
8
|
Wang Y, Yu Y, Pang Y, Yu H, Zhang W, Zhao X, Yu J. The distinct roles of zinc finger CCHC-type (ZCCHC) superfamily proteins in the regulation of RNA metabolism. RNA Biol 2021; 18:2107-2126. [PMID: 33787465 DOI: 10.1080/15476286.2021.1909320] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The zinc finger CCHC-type (ZCCHC) superfamily proteins, characterized with the consensus sequence C-X2-C-X4-H-X4-C, are accepted to have high-affinity binding to single-stranded nucleic acids, especially single-stranded RNAs. In human beings 25 ZCCHC proteins have been annotated in the HGNC database. Of interest is that among the family, most members are involved in the multiple steps of RNA metabolism. In this review, we focus on the diverged roles of human ZCCHC proteins on RNA transcription, biogenesis, splicing, as well as translation and degradation.
Collapse
Affiliation(s)
- Yishu Wang
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China; Shanghai Key Laboratory of Embryo Original Diseases, Shanghai, China
| | - Yu Yu
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yidan Pang
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Haojun Yu
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenqi Zhang
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xian Zhao
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jianxiu Yu
- Department of Biochemistry and Molecular Cell Biology, State Key Laboratory of Oncogenes and Related Genes, Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| |
Collapse
|
9
|
Nasamran CA, Sachan ANS, Mott J, Kuras YI, Scherzer CR, Study HB, Ricciardelli E, Jepsen K, Edland SD, Fisch KM, Desplats P. Differential blood DNA methylation across Lewy body dementias. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2021; 13:e12156. [PMID: 33665346 PMCID: PMC7896631 DOI: 10.1002/dad2.12156] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 12/29/2020] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD) are characterized by cognitive alterations, visual hallucinations, and motor impairment. Diagnosis is based on type and timing of clinical manifestations; however, determination of clinical subtypes is challenging. The utility of blood DNA methylation as a biomarker for Lewy body disorders (LBD) is mostly unexplored. METHODS We performed a cross-sectional analysis of blood methylation in 42 DLB and 50 PDD cases applying linear models to compare groups and logistic least absolute shrinkage and selection operator regression to explore the discriminant power of methylation signals. RESULTS DLB blood shows differential methylation compared to PDD. Some methylation changes associate with core features of LBD. Sets of probes show high predictive value to discriminate between variants. DISCUSSION Our study is the first to explore LBD blood methylation. Despite overlapping clinical presentation, we detected differential epigenetic signatures that, if confirmed in independent cohorts, could be developed into useful biomarkers.
Collapse
Affiliation(s)
- Chanond A. Nasamran
- Center for Computational Biology & BioinformaticsDepartment of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Anubhav Nikunj Singh Sachan
- Division of Biostatistics, Department of Family Medicine and Public HealthUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Jennifer Mott
- Department of Neurosciences, School of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Yuliya I. Kuras
- Center for Advanced Parkinson Research and Precision Neurology Program, Harvard Medical SchoolBrigham & Women's HospitalBostonMassachusettsUSA
| | - Clemens R. Scherzer
- Center for Advanced Parkinson Research and Precision Neurology Program, Harvard Medical SchoolBrigham & Women's HospitalBostonMassachusettsUSA
| | | | - Eugenia Ricciardelli
- Genomics CenterInstitute for Genomics MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Kristen Jepsen
- Genomics CenterInstitute for Genomics MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Steven D. Edland
- Department of Neurosciences, School of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
- Department of Family Medicine and Public HealthUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Kathleen M. Fisch
- Center for Computational Biology & BioinformaticsDepartment of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
| | - Paula Desplats
- Department of Neurosciences, School of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
- Department of Pathology, School of MedicineUniversity of California San DiegoLa JollaCaliforniaUSA
| |
Collapse
|
10
|
Drummond E, Pires G, MacMurray C, Askenazi M, Nayak S, Bourdon M, Safar J, Ueberheide B, Wisniewski T. Phosphorylated tau interactome in the human Alzheimer's disease brain. Brain 2021; 143:2803-2817. [PMID: 32812023 DOI: 10.1093/brain/awaa223] [Citation(s) in RCA: 162] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 05/05/2020] [Accepted: 05/22/2020] [Indexed: 01/07/2023] Open
Abstract
Accumulation of phosphorylated tau is a key pathological feature of Alzheimer's disease. Phosphorylated tau accumulation causes synaptic impairment, neuronal dysfunction and formation of neurofibrillary tangles. The pathological actions of phosphorylated tau are mediated by surrounding neuronal proteins; however, a comprehensive understanding of the proteins that phosphorylated tau interacts with in Alzheimer's disease is surprisingly limited. Therefore, the aim of this study was to determine the phosphorylated tau interactome. To this end, we used two complementary proteomics approaches: (i) quantitative proteomics was performed on neurofibrillary tangles microdissected from patients with advanced Alzheimer's disease; and (ii) affinity purification-mass spectrometry was used to identify which of these proteins specifically bound to phosphorylated tau. We identified 542 proteins in neurofibrillary tangles. This included the abundant detection of many proteins known to be present in neurofibrillary tangles such as tau, ubiquitin, neurofilament proteins and apolipoprotein E. Affinity purification-mass spectrometry confirmed that 75 proteins present in neurofibrillary tangles interacted with PHF1-immunoreactive phosphorylated tau. Twenty-nine of these proteins have been previously associated with phosphorylated tau, therefore validating our proteomic approach. More importantly, 34 proteins had previously been associated with total tau, but not yet linked directly to phosphorylated tau (e.g. synaptic protein VAMP2, vacuolar-ATPase subunit ATP6V0D1); therefore, we provide new evidence that they directly interact with phosphorylated tau in Alzheimer's disease. In addition, we also identified 12 novel proteins, not previously known to be physiologically or pathologically associated with tau (e.g. RNA binding protein HNRNPA1). Network analysis showed that the phosphorylated tau interactome was enriched in proteins involved in the protein ubiquitination pathway and phagosome maturation. Importantly, we were able to pinpoint specific proteins that phosphorylated tau interacts with in these pathways for the first time, therefore providing novel potential pathogenic mechanisms that can be explored in future studies. Combined, our results reveal new potential drug targets for the treatment of tauopathies and provide insight into how phosphorylated tau mediates its toxicity in Alzheimer's disease.
Collapse
Affiliation(s)
- Eleanor Drummond
- Brain and Mind Centre and Central Clinical School, Faculty of Medicine and Health, University of Sydney, Australia.,Centre for Cognitive Neurology, Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Geoffrey Pires
- Centre for Cognitive Neurology, Department of Neurology, New York University School of Medicine, New York, NY, USA.,Alzheimer's and Prion Diseases Team, Paris Brain Institute, CNRS, UMR 7225, INSERM 1127, Sorbonne University UM75, Paris, France
| | - Claire MacMurray
- Centre for Cognitive Neurology, Department of Neurology, New York University School of Medicine, New York, NY, USA
| | | | - Shruti Nayak
- Proteomics Laboratory, Division of Advanced Research Technologies, NYU School of Medicine, New York, NY, USA
| | - Marie Bourdon
- Centre for Cognitive Neurology, Department of Neurology, New York University School of Medicine, New York, NY, USA
| | - Jiri Safar
- Department of Pathology, Case Western Reserve University, Cleveland, OH, USA.,Department of Neurology, Case Western Reserve University, Cleveland, OH, USA
| | - Beatrix Ueberheide
- Biomedical Hosting LLC, USA.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Thomas Wisniewski
- Centre for Cognitive Neurology, Department of Neurology, New York University School of Medicine, New York, NY, USA.,Department of Psychiatry, New York University School of Medicine, New York, NY, USA
| |
Collapse
|
11
|
Wagner RE, Frye M. Noncanonical functions of the serine-arginine-rich splicing factor (SR) family of proteins in development and disease. Bioessays 2021; 43:e2000242. [PMID: 33554347 DOI: 10.1002/bies.202000242] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 12/19/2022]
Abstract
Members of the serine/arginine (SR)-rich protein family of splicing factors play versatile roles in RNA processing steps and are often essential for normal development. Dynamic changes in RNA processing and turnover allow fast cellular adaptions to a changing microenvironment and thereby closely cooperate with transcription factor networks that establish cell identity within tissues. SR proteins play fundamental roles in the processing of pre-mRNAs by regulating constitutive and alternative splicing. More recently, SR proteins have also been implicated in other aspects of RNA metabolism such as mRNA stability, transport and translation. The- emerging noncanonical functions highlight the multifaceted functions of these SR proteins and identify them as important coordinators of gene expression programmes. Accordingly, most SR proteins are essential for normal cell function and their misregulation contributes to human diseases such as cancer.
Collapse
Affiliation(s)
- Rebecca E Wagner
- German Cancer Research Center - Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| | - Michaela Frye
- German Cancer Research Center - Deutsches Krebsforschungszentrum (DKFZ), Heidelberg, Germany
| |
Collapse
|
12
|
Tubeuf H, Charbonnier C, Soukarieh O, Blavier A, Lefebvre A, Dauchel H, Frebourg T, Gaildrat P, Martins A. Large-scale comparative evaluation of user-friendly tools for predicting variant-induced alterations of splicing regulatory elements. Hum Mutat 2020; 41:1811-1829. [PMID: 32741062 DOI: 10.1002/humu.24091] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 07/11/2020] [Accepted: 07/26/2020] [Indexed: 12/20/2022]
Abstract
Discriminating which nucleotide variants cause disease or contribute to phenotypic traits remains a major challenge in human genetics. In theory, any intragenic variant can potentially affect RNA splicing by altering splicing regulatory elements (SREs). However, these alterations are often ignored mainly because pioneer SRE predictors have proved inefficient. Here, we report the first large-scale comparative evaluation of four user-friendly SRE-dedicated algorithms (QUEPASA, HEXplorer, SPANR, and HAL) tested both as standalone tools and in multiple combined ways based on two independent benchmark datasets adding up to >1,300 exonic variants studied at the messenger RNA level and mapping to 89 different disease-causing genes. These methods display good predictive power, based on decision thresholds derived from the receiver operating characteristics curve analyses, with QUEPASA and HAL having the best accuracies either as standalone or in combination. Still, overall there was a tight race between the four predictors, suggesting that all methods may be of use. Additionally, QUEPASA and HEXplorer may be beneficial as well for predicting variant-induced creation of pseudoexons deep within introns. Our study highlights the potential of SRE predictors as filtering tools for identifying disease-causing candidates among the plethora of variants detected by high-throughput DNA sequencing and provides guidance for their use in genomic medicine settings.
Collapse
Affiliation(s)
- Hélène Tubeuf
- Inserm U1245, UNIROUEN, Normandie University, Normandy Centre for Genomic and Personalized Medicine, Rouen, France.,Interactive Biosoftware, Rouen, France
| | - Camille Charbonnier
- Inserm U1245, UNIROUEN, Normandie University, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Omar Soukarieh
- Inserm U1245, UNIROUEN, Normandie University, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | | | - Arnaud Lefebvre
- Computer Science, Information Processing and Systems Laboratory, UNIROUEN, Normandie University, Mont-Saint-Aignan, France
| | - Hélène Dauchel
- Computer Science, Information Processing and Systems Laboratory, UNIROUEN, Normandie University, Mont-Saint-Aignan, France
| | - Thierry Frebourg
- Inserm U1245, UNIROUEN, Normandie University, Normandy Centre for Genomic and Personalized Medicine, Rouen, France.,Department of Genetics, University Hospital, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Pascaline Gaildrat
- Inserm U1245, UNIROUEN, Normandie University, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| | - Alexandra Martins
- Inserm U1245, UNIROUEN, Normandie University, Normandy Centre for Genomic and Personalized Medicine, Rouen, France
| |
Collapse
|
13
|
SRSF7 maintains its homeostasis through the expression of Split-ORFs and nuclear body assembly. Nat Struct Mol Biol 2020; 27:260-273. [PMID: 32123389 PMCID: PMC7096898 DOI: 10.1038/s41594-020-0385-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 01/23/2020] [Indexed: 02/08/2023]
Abstract
SRSF7 is an essential RNA-binding protein whose misexpression promotes cancer. Here, we describe how SRSF7 maintains its protein homeostasis in murine P19 cells using an intricate negative feedback mechanism. SRSF7 binding to its premessenger RNA promotes inclusion of a poison cassette exon and transcript degradation via nonsense-mediated decay (NMD). However, elevated SRSF7 levels inhibit NMD and promote translation of two protein halves, termed Split-ORFs, from the bicistronic SRSF7-PCE transcript. The first half acts as dominant-negative isoform suppressing poison cassette exon inclusion and instead promoting the retention of flanking introns containing repeated SRSF7 binding sites. Massive SRSF7 binding to these sites and its oligomerization promote the assembly of large nuclear bodies, which sequester SRSF7 transcripts at their transcription site, preventing their export and restoring normal SRSF7 protein levels. We further show that hundreds of human and mouse NMD targets, especially RNA-binding proteins, encode potential Split-ORFs, some of which are expressed under specific cellular conditions.
Collapse
|
14
|
Sirt1 enhances tau exon 10 inclusion and improves spatial memory of Htau mice. Aging (Albany NY) 2019; 10:2498-2510. [PMID: 30243024 PMCID: PMC6188499 DOI: 10.18632/aging.101564] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 09/14/2018] [Indexed: 12/18/2022]
Abstract
Alternative splicing of tau exon 10 generates tau isoforms with three or four microtubule binding repeats, named 3R-tau and 4R-tau, respectively. Dysregulation of tau exon 10 splicing could cause neurofibrillary degeneration. Acetylation is one of the major post-translational protein modifications in the cell by attachment of the acetyl group to either the α-amino group of the N-terminus of proteins or to the ε-amino group of lysine residues. Sirt1, one member in mammalian Sirtuin family, deacetylates protein and is associated closely with age-related diseases including Alzheimer’s disease. However, the role of Sirt1 in tau exon 10 splicing remains elusive. In the present study, we determined the role of Sirt1 in tau exon 10 splicing. We found that activation of Sirt1 by resveratrol enhanced tau exon 10 inclusion, leading to 4R-tau expression. Sirt1 interacted with splicing factor 9G8, deacetylated it at Lys24, and suppressed its function in promoting tau exon 10 exclusion. Moreover, resveratrol improved learning and spatial memory in Htau mice. These findings suggest that Sirt1 may serve as a new drug target for Alzheimer’s Disease related tauopathies and resveratrol may be used to correct dysregulated tau exon 10 with 3R-tau > 4R-tau.
Collapse
|
15
|
Abstract
Alzheimer's disease (AD), the most common form of dementia, is characterized by extracellular β-amyloid plaques and intracellular neurofibrillary tangles (NFTs), which are considered as major targets for AD therapies. However, no effective therapy is available to cure or prevent the progression of AD up until now. Accumulation of NFTs, which consist of abnormally hyperphosphorylated tau, is directly correlated with the degree of dementia in AD patients. Emerging evidence indicates that the prion-like seeding and spreading of tau pathology may be the key driver of AD. In the past decades, greater understanding of tau pathway reveals new targets for the development of specific therapies. Here, we review the recent research progress in the mechanism underlying tau pathology in AD and briefly introduce tau-based therapeutics.
Collapse
Affiliation(s)
- Dandan Chu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education of China, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, PR China
| | - Fei Liu
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, United States
| |
Collapse
|
16
|
Llorens-Agost M, Luessing J, van Beneden A, Eykelenboom J, O’Reilly D, Bicknell LS, Reynolds JJ, van Koegelenberg M, Hurles ME, Brady AF, Jackson AP, Stewart GS, Lowndes NF. Analysis of novel missense ATR mutations reveals new splicing defects underlying Seckel syndrome. Hum Mutat 2018; 39:1847-1853. [PMID: 30199583 PMCID: PMC7615757 DOI: 10.1002/humu.23648] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 08/17/2018] [Accepted: 09/06/2018] [Indexed: 01/01/2023]
Abstract
Ataxia Telangiectasia and Rad3 related (ATR) is one of the main regulators of the DNA damage response. It coordinates cell cycle checkpoint activation, replication fork stability, restart and origin firing to maintain genome integrity. Mutations of the ATR gene have been reported in Seckel patients, who suffer from a rare genetic disease characterized by severe microcephaly and growth retardation. Here, we report the case of a Seckel patient with compound heterozygous mutations in ATR. One allele has an intronic mutation affecting splicing of neighboring exons, the other an exonic missense mutation, producing the variant p.Lys1665Asn, of unknown pathogenicity. We have modeled this novel missense mutation, as well as a previously described missense mutation p.Met1159Ile, and assessed their effect on ATR function. Interestingly, our data indicate that both missense mutations have no direct effect on protein function, but rather result in defective ATR splicing. These results emphasize the importance of splicing mutations in Seckel Syndrome.
Collapse
Affiliation(s)
- Marta Llorens-Agost
- Centre for Chromosome Biology, National University of Ireland in Galway, Galway, Ireland
| | - Janna Luessing
- Centre for Chromosome Biology, National University of Ireland in Galway, Galway, Ireland
| | - Amandine van Beneden
- Centre for Chromosome Biology, National University of Ireland in Galway, Galway, Ireland
| | - John Eykelenboom
- Centre for Chromosome Biology, National University of Ireland in Galway, Galway, Ireland
- School of Life Sciences, University of Dundee, Dundee, Scotland
| | - Dawn O’Reilly
- Oxford Stem Cell Institute, University of Oxford, Oxford, UK
| | - Louise S Bicknell
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - John J Reynolds
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | | | - Matthew E Hurles
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Cambridge, UK
| | - Angela F Brady
- North West Thames Regional Genetics Service, Northwick Park Hospital, Harrow, UK
| | - Andrew P Jackson
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburg, Scotland
| | - Grant S Stewart
- Institute of Cancer and Genomic Sciences, University of Birmingham, Birmingham, UK
| | - Noel F Lowndes
- Centre for Chromosome Biology, National University of Ireland in Galway, Galway, Ireland
| |
Collapse
|
17
|
Welden JR, van Doorn J, Nelson PT, Stamm S. The human MAPT locus generates circular RNAs. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2753-2760. [PMID: 29729314 DOI: 10.1016/j.bbadis.2018.04.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 04/19/2018] [Accepted: 04/30/2018] [Indexed: 01/07/2023]
Abstract
The microtubule-associated protein Tau, generated by the MAPT gene is involved in dozens of neurodegenerative conditions ("tauopathies"), including Alzheimer's disease (AD) and frontotemporal lobar degeneration/frontotemporal dementia (FTLD/FTD). The pre-mRNA of MAPT is well studied and its aberrant pre-mRNA splicing is associated with frontotemporal dementia. Using a PCR screen of RNA from human brain tissues, we found that the MAPT locus generates circular RNAs through a backsplicing mechanism from exon 12 to either exon 10 or 7. MAPT circular RNAs are localized in the cytosol and contain open reading frames encoding Tau protein fragments. The MAPT exon 10 is alternatively spliced and proteins involved in its regulation, such as CLK2, SRSF7/9G8, PP1 (protein phosphatase 1) and NIPP1 (nuclear inhibitor of PP1) reduce the abundance of the circular MAPT exon 12 → 10 backsplice RNA after being transfected into cultured HEK293 cells. In summary, we report the identification of new bona fide human brain RNAs produced from the MAPT locus. These may be a component of normal human brain Tau regulation and, since the circular RNAs could generate high molecular weight proteins with multiple microtubule binding sites, they could contribute to taupathies.
Collapse
Affiliation(s)
| | | | - Peter T Nelson
- University of Kentucky, Lexington, KY 40503, United States
| | - Stefan Stamm
- University of Kentucky, Lexington, KY 40503, United States.
| |
Collapse
|
18
|
Fu Y, Wang Y. SRSF7 knockdown promotes apoptosis of colon and lung cancer cells. Oncol Lett 2018; 15:5545-5552. [PMID: 29556298 PMCID: PMC5844074 DOI: 10.3892/ol.2018.8072] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 01/10/2018] [Indexed: 02/04/2023] Open
Abstract
Serine/arginine-rich (SR) proteins are a family of important splicing factors, which are involved in multiple aspects of RNA processing, including splicing, mRNA nuclear export, mRNA stability and translation. Previous studies have identified a number of SR proteins that exhibit abnormal expression in various tumor types. In the present study, the expression and function of serine/arginine-rich splicing factor 7 (SRSF7) were investigated in colon and lung cancer. Using tissue immunohistochemistry, it was observed that SRSF7 was overexpressed in colon and lung cancer tissues. As the role of SRSF7 in cancer remains to be fully elucidated, the expression of SRSF7 was knocked down in the present study by transfecting SRSF7-specific small interfering RNAs (siRNAs) into the HCT116 colon cancer cell line and A549 lung cancer cell line, which exhibited elevated expression of SRSF7. MTS assays, western blot analysis, flow cytometry and spectrofluorometer analyses were performed to assess the effects of SRSF7 knockdown on the proliferation and apoptosis of cells. The results demonstrated that the expression of SRSF7 was efficiently knocked down by SRSF7 siRNA, and that SRSF7 knockdown inhibited proliferation and enhanced apoptosis of HCT116 and A549 cells. Further experiments involving BEAS-2B cells stably overexpressing SRSF7, and A549 cells with stable knockdown of SRSF7 revealed that SRSF7 regulated the splicing of the apoptosis regulator Fas. Collectively, these data indicated that SRSF7 is critical for the survival of colon and lung cancer cells, and may be a potential therapeutic target for the treatment of colon and lung cancer.
Collapse
Affiliation(s)
- Yu Fu
- College of Bioscience and Bioengineering, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018, P.R. China
| | - Yingze Wang
- College of Bioscience and Bioengineering, Hebei University of Science and Technology, Shijiazhuang, Hebei 050018, P.R. China
| |
Collapse
|
19
|
Gu J, Chen F, Iqbal K, Gong CX, Wang X, Liu F. Transactive response DNA-binding protein 43 (TDP-43) regulates alternative splicing of tau exon 10: Implications for the pathogenesis of tauopathies. J Biol Chem 2017; 292:10600-10612. [PMID: 28487370 DOI: 10.1074/jbc.m117.783498] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/08/2017] [Indexed: 12/14/2022] Open
Abstract
Hyperphosphorylation and aggregation of the neuronal protein tau are responsible for neurodegenerative diseases called tauopathies. Dysregulation of the alternative splicing of tau exon 10 results in alterations of the ratio of two tau isoforms, 3R-tau and 4R-tau, which have been seen in several tauopathies. Transactive response DNA-binding protein of 43 kDa (TDP-43) is involved in the regulation of RNA processing, including splicing. Cytoplasmic aggregation of TDP-43 has been observed in the brains of individuals with chronic traumatic encephalopathy or Alzheimer's disease, diseases in which neurofibrillary tangles of hyperphosphorylated tau are hallmarks. Here, we investigated the role of TDP-43 in tau exon 10 splicing. We found that TDP-43 promoted tau exon 10 inclusion, which increased production of the 4R-tau isoform. Moreover, TDP-43 could bind to intron 9 of tau pre-mRNA. Deletion of the TDP-43 N or C terminus promoted its cytoplasmic aggregation and abolished or diminished TDP-43-promoted tau exon 10 inclusion. Several TDP-43 mutations associated with amyotrophic lateral sclerosis or frontotemporal lobar degeneration with ubiquitin inclusions promoted tau exon 10 inclusion more effectively than wild-type TDP-43 but did not affect TDP-43 cytoplasmic aggregation in cultured cells. The ratio of 3R-tau/4R-tau was decreased in transgenic mouse brains expressing human TDP-43 and increased in the brains expressing the disease-causing mutation TDP-43M337V, in which cytoplasmic TDP-43 was increased. These findings suggest that TDP-43 promotes tau exon 10 inclusion and 4R-tau expression and that disease-related changes of TDP-43, truncations and mutations, affect its function in tau exon 10 splicing, possibly because of TDP-43 mislocalization to the cytoplasm.
Collapse
Affiliation(s)
- Jianlan Gu
- From the Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration and.,Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, and.,Department of Biochemistry and Molecular Biology, School of Medicine, Nantong University, Nantong, Jiangsu 226001, China
| | - Feng Chen
- From the Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration and.,Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, and
| | - Khalid Iqbal
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, and
| | - Cheng-Xin Gong
- From the Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration and.,Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, and
| | - Xinglong Wang
- Department of Pathology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Fei Liu
- From the Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-innovation Center of Neuroregeneration and .,Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, and
| |
Collapse
|
20
|
Boguslawska J, Sokol E, Rybicka B, Czubaty A, Rodzik K, Piekielko-Witkowska A. microRNAs target SRSF7 splicing factor to modulate the expression of osteopontin splice variants in renal cancer cells. Gene 2016; 595:142-149. [DOI: 10.1016/j.gene.2016.09.031] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 09/19/2016] [Accepted: 09/21/2016] [Indexed: 12/30/2022]
|
21
|
Liu B, Bossing T. Single neuron transcriptomics identify SRSF/SR protein B52 as a regulator of axon growth and Choline acetyltransferase splicing. Sci Rep 2016; 6:34952. [PMID: 27725692 PMCID: PMC5057162 DOI: 10.1038/srep34952] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 09/21/2016] [Indexed: 01/14/2023] Open
Abstract
We removed single identified neurons from living Drosophila embryos to gain insight into the transcriptional control of developing neuronal networks. The microarray analysis of the transcriptome of two sibling neurons revealed seven differentially expressed transcripts between both neurons (threshold: log21.4). One transcript encodes the RNA splicing factor B52. Loss of B52 increases growth of axon branches. B52 function is also required for Choline acetyltransferase (ChAT ) splicing. At the end of embryogenesis, loss of B52 function impedes splicing of ChAT, reduces acetylcholine synthesis, and extends the period of uncoordinated muscle twitches during larval hatching. ChAT regulation by SRSF proteins may be a conserved feature since changes in SRSF5 expression and increased acetylcholine levels in brains of bipolar disease patients have been reported recently.
Collapse
Affiliation(s)
- Boyin Liu
- School of Biological Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Torsten Bossing
- School of Biomedical and Healthcare Sciences, Plymouth University, John Bull Building, Plymouth, PL6 8BU, U.K
| |
Collapse
|
22
|
Functional Analysis of Mutations in Exon 9 of NF1 Reveals the Presence of Several Elements Regulating Splicing. PLoS One 2015; 10:e0141735. [PMID: 26509978 PMCID: PMC4624989 DOI: 10.1371/journal.pone.0141735] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 10/11/2015] [Indexed: 11/19/2022] Open
Abstract
Neurofibromatosis type 1 (NF1) is one of the most common human hereditary disorders, predisposing individuals to the development of benign and malignant tumors in the nervous system, as well as other clinical manifestations. NF1 is caused by heterozygous mutations in the NF1 gene and around 25% of the pathogenic changes affect pre-mRNA splicing. Since the molecular mechanisms affected by these mutations are poorly understood, we have analyzed the splicing mutations identified in exon 9 of NF1, which is particularly prone to such changes, to better define the possible splicing regulatory elements. Using a minigene approach, we studied the effect of five splicing mutations in this exon described in patients. These highlighted three regulatory motifs within the exon. An in vivo splicing analysis of an extensive collection of changes generated in the minigene demonstrated that the CG motif at c.910-911 is critical for the recognition of exon 9. We also found that the GC motif at c.945-946 is involved in exon recognition through SRSF2 and that this motif is part of a Composite Exon Splicing Regulatory Element made up of physically overlapping enhancer and silencer elements. Finally, through an in vivo splicing analysis and in vitro binding assays, we demonstrated that the c.1007G>A mutation creates an Exonic Splicing Silencer element that binds the hnRNPA1 protein. The complexity of the splicing regulatory elements present in exon 9 is most likely responsible for the fact that mutations in this region represent 25% of all exonic changes that affect splicing in the NF1 gene.
Collapse
|
23
|
Qian W, Liu F. Regulation of alternative splicing of tau exon 10. Neurosci Bull 2014; 30:367-77. [PMID: 24627328 DOI: 10.1007/s12264-013-1411-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 01/03/2014] [Indexed: 12/22/2022] Open
Abstract
The neuronal microtubule-associated protein tau is abnormally hyperphosphorylated and aggregated into neurofibrillary tangles in the brains of individuals with Alzheimer's disease and related neurodegenerative disorders. The adult human brain expresses six isoforms of tau generated by alternative splicing of exons 2, 3, and 10 of its pre-mRNA. Exon 10 encodes the second microtubule-binding repeat of tau. Its alternative splicing produces tau isoforms with either three or four microtubule-binding repeats, termed 3R-tau and 4Rtau. In the normal adult human brain, the level of 3R-tau is approximately equal to that of 4R-tau. Several silent and intronic mutations of the tau gene associated with FTDP-17T (frontotemporal dementia with Parkinsonism linked to chromosome 17 and specifically characterized by tau pathology) only disrupt exon 10 splicing, but do not influence the primary sequence of the tau protein. Thus, abnormal exon 10 splicing is sufficient to cause neurodegeneration and dementia. Here, we review the regulation of tau exon 10 splicing by cis-elements and trans-factors and summarize all the mutations associated with FTDP-17T and related tauopathies. The findings suggest that correction of exon 10 splicing may be a potential target for tau exon 10 splicing-related tauopathies.
Collapse
Affiliation(s)
- Wei Qian
- Department of Biochemistry and Molecular Biology, School of Medicine, Nantong University, Nantong, 226001, China
| | | |
Collapse
|
24
|
Iqbal K, Liu F, Gong CX. Alzheimer disease therapeutics: focus on the disease and not just plaques and tangles. Biochem Pharmacol 2014; 88:631-9. [PMID: 24418409 DOI: 10.1016/j.bcp.2014.01.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/26/2013] [Accepted: 01/02/2014] [Indexed: 12/13/2022]
Abstract
The bulk of AD research during the last 25 years has been Aβ-centric based on a strong faith in the Amyloid Cascade Hypothesis which is not supported by the data on humans. To date, Aβ-based therapeutic clinical trials on sporadic cases of AD have been negative. Although most likely the major reason for the failure is that Aβ is not an effective therapeutic target for sporadic AD, initiation of the treatment at mild to moderate stages of the disease is blamed as too late to be effective. Clinical trials on presymptomatic familial AD cases have been initiated with the logic that Aβ is a trigger of the disease and hence initiation of the Aβ immunotherapies several years before any clinical symptoms would be effective. There is an urgent need to explore targets other than Aβ. There is now increasing interest in inhibiting tau pathology, which does have a far more compelling rationale than Aβ. AD is multifactorial and over 99% of the cases are the sporadic form of the disease. Understanding of the various etiopathogenic mechanisms of sporadic AD and generation of the disease-relevant animal models are required to develop rational therapeutic targets and therapies. Treatment of AD will require both inhibition of neurodegeneration and regeneration of the brain.
Collapse
Affiliation(s)
- Khalid Iqbal
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.
| | - Fei Liu
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA
| | - Cheng-Xin Gong
- Department of Neurochemistry, Inge Grundke-Iqbal Research Floor, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA
| |
Collapse
|
25
|
Wong J. Altered expression of RNA splicing proteins in Alzheimer's disease patients: evidence from two microarray studies. Dement Geriatr Cogn Dis Extra 2013; 3:74-85. [PMID: 23637700 PMCID: PMC3617979 DOI: 10.1159/000348406] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND/AIMS Dysregulation of pre-mRNA splicing from an altered expression of RNA splice-regulatory proteins may act as the convergence point underlying aberrant gene expression changes in Alzheimer's disease (AD). METHODS Two microarray datasets from a control/AD postmortem brain cohort of 31 subjects - 9 controls and 22 AD subjects (National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) database) - were used. RESULTS Between the two microarray studies, the expression of six splice-regulatory protein genes showed concordant changes in AD. These genes were then correlated with gene expression changes of transcripts reported to be altered in AD. Amyloid beta (A4) precursor protein and tropomyosin receptor kinase B transcripts were found to correlate significantly with the same splice-regulatory proteins in the two studies. CONCLUSION This study highlights a susceptibility network that can potentially link a number of susceptibility genes.
Collapse
Affiliation(s)
- Jenny Wong
- Illawarra Health and Medical Research Institute, and School of Biological Sciences, University of Wollongong, Wollongong, N.S.W., Australia
| |
Collapse
|
26
|
Oleaga C, Welten S, Belloc A, Solé A, Rodriguez L, Mencia N, Selga E, Tapias A, Noé V, Ciudad CJ. Identification of novel Sp1 targets involved in proliferation and cancer by functional genomics. Biochem Pharmacol 2012; 84:1581-91. [PMID: 23018034 DOI: 10.1016/j.bcp.2012.09.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 09/04/2012] [Accepted: 09/17/2012] [Indexed: 01/07/2023]
Abstract
Sp1 is a transcription factor regulating many genes through its DNA binding domain, containing three zinc fingers. We were interested in identifying target genes regulated by Sp1, particularly those involved in proliferation and cancer. Our approach was to treat HeLa cells with a siRNA directed against Sp1 mRNA to decrease the expression of Sp1 and, in turn, the genes activated by this transcription factor. Sp1-siRNA treatment led to a great number of differentially expressed genes as determined by whole genome cDNA microarray analysis. Underexpressed genes were selected since they represent putative genes activated by Sp1 and classified in six Gene Onthology categories, namely proliferation and cancer, mRNA processing, lipid metabolism, glucidic metabolism, transcription and translation. Putative Sp1 binding sites were found in the promoters of the selected genes using the Match™ software. After literature mining, 11 genes were selected for further validation. Underexpression by qRT-PCR was confirmed for the 11 genes plus Sp1 in HeLa cells after Sp1-siRNA treatment. EMSA and ChIP assays were performed to test for binding of Sp1 to the promoters of these genes. We observed binding of Sp1 to the promoters of RAB20, FGF21, IHPK2, ARHGAP18, NPM3, SRSF7, CALM3, PGD and Sp1 itself. Furthermore, the mRNA levels of RAB20, FGF21 and IHPK2 and luciferase activity for these three genes related to proliferation and cancer, were determined after overexpression of Sp1 in HeLa cells, to confirm their regulation by Sp1. Involvement of these three genes in proliferation was validated by gene silencing using polypurine reverse hoogsteen hairpins.
Collapse
Affiliation(s)
- Carlota Oleaga
- Department of Biochemistry and Molecular Biology, School of Pharmacy, University of Barcelona, Barcelona, Spain.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Impaired Post-transcriptional Regulation in Alzheimer′s Disease*. PROG BIOCHEM BIOPHYS 2012. [DOI: 10.3724/sp.j.1206.2012.00211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
28
|
Wong J, Garner B, Halliday GM, Kwok JBJ. Srp20 regulates TrkB pre-mRNA splicing to generate TrkB-Shc transcripts with implications for Alzheimer's disease. J Neurochem 2012; 123:159-71. [PMID: 22788679 DOI: 10.1111/j.1471-4159.2012.07873.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Previously, we reported elevated levels of the neuron-specific tropomyosin receptor kinase B (TrkB) transcript, TrkB- sarc homology containing (Shc) in the hippocampus of Alzheimer's disease (AD) brains. In this study, we determined how TrkB-Shc transcripts are increased in AD. Utilizing a TrkB minigene transiently transfected into SHSY5Y cells, we found increased exon 19 inclusion in TrkB minigene transcripts (to generate TrkB-Shc) following cellular exposure to amyloid beta 1-42 (Αβ(42)). As this suggested altered TrkB pre-mRNA splicing in AD, we conducted an in silico screening for putative splice regulatory protein-binding sites in the intron/exon splice regulatory regions of exons 18 and 19 of the TrkB gene and then assessed their gene expression profiles using a microarray database of control/AD post-mortem human hippocampal brain tissue. We found significant changes in serine/arginine protein 20 (Srp20) gene expression in AD cases and confirmed this using a second cohort of control/AD. In vitro, we found increased Srp20 mRNA levels in SHSY5Y cells treated with Αβ(42) fibrils. Moreover, Srp20 over-expression was found to increase exon 19 inclusion in TrkB minigene transcripts and ratio of endogenous TrkB-Shc:TrkB-TK+ mRNA expression. Conversely, Srp20 expression knockdown produced the opposite effects. Our findings suggest that dysregulation of factors regulating TrkB pre-mRNA splicing may contribute to gene expression changes that occur in AD.
Collapse
Affiliation(s)
- Jenny Wong
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia.
| | | | | | | |
Collapse
|
29
|
O'Bryan MK, Grealy A, Stahl PJ, Schlegel PN, McLachlan RI, Jamsai D. Genetic variants in the ETV5 gene in fertile and infertile men with nonobstructive azoospermia associated with Sertoli cell-only syndrome. Fertil Steril 2012; 98:827-35.e1-3. [PMID: 22771031 DOI: 10.1016/j.fertnstert.2012.06.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2012] [Revised: 06/12/2012] [Accepted: 06/12/2012] [Indexed: 12/23/2022]
Abstract
OBJECTIVE To assess the association between genetic variants in the ETV5 gene with nonobstructive azoospermia (NOA) associated with Sertoli cell-only (SCO) syndrome. DESIGN Genetic association study. SETTING University. PATIENT(S) Australian men (65 SCO, 53 NOA, and 242 fertile men) and American men (86 SCO and 54 fertile men). INTERVENTION(S) Paraffin-embedded human testicular tissue was sectioned and processed for immunofluorescence. Direct DNA sequencing and polymerase chain reaction-based SNP detection were performed to define genetic variants in the ETV5 gene. MAIN OUTCOME MEASURE(S) The localization of ETV5 in the human testis and the presence of ETV5 genetic variants in fertile and infertile men. RESULT(S) ETV5 is localized to the cytoplasm and nucleus of Sertoli and germ cells in adult human testes. We identified six previously reported and six new genetic variants in the ETV5 gene. Of these, the allele frequency of the homozygous +48845 G>T (TT allele) variant was significantly higher in the SCO and NOA Australian men compared with fertile men. CONCLUSION(S) The homozygous +48845 G>T (TT allele) variant confers a higher risk for male infertility associated with NOA and SCO in Australian men.
Collapse
Affiliation(s)
- Moira K O'Bryan
- Department of Anatomy and Developmental Biology, School of Biomedical Sciences, Faculty of Medicine, Nursing, and Health Sciences, Monash University, Clayton, Victoria, Australia
| | | | | | | | | | | |
Collapse
|
30
|
Ding S, Shi J, Qian W, Iqbal K, Grundke-Iqbal I, Gong CX, Liu F. Regulation of alternative splicing of tau exon 10 by 9G8 and Dyrk1A. Neurobiol Aging 2012; 33:1389-99. [PMID: 21215488 PMCID: PMC3085640 DOI: 10.1016/j.neurobiolaging.2010.11.021] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 08/23/2010] [Accepted: 11/21/2010] [Indexed: 12/19/2022]
Abstract
Adult human brain expresses 6 isoforms of tau protein as a result of alternative splicing. Alternative splicing of exon 10 (E10) leads to tau isoforms containing either 3 (3R-tau) or 4 (4R-tau) microtubule-binding repeats. Imbalance in the 3R-tau/4R-tau ratio causes neurofibrillary degeneration and dementia. Here, we demonstrated that the dual-specificity tyrosine phosphorylation-regulated kinase 1A (Dyrk1A) interacted with the splicing factor 9G8 and phosphorylated it at several serine residues. Dyrk1A itself promoted tau E10 inclusion, whereas 9G8 inhibited E10 inclusion, and these actions were variable depending on the cell types. Coexpression of Dyrk1A and 9G8 led to their translocation from the nucleus to the cytoplasm and suppressed their ability to regulate tau exon 10 splicing. This action is probably due to their interaction-induced translocation from the nucleus, where the regulation of tau E10 splicing occurs, to the cytoplasm. These findings provide novel insights into the molecular mechanism of the regulation of tau E10 splicing and further our understanding of the neurodegeneration caused by dysregulation of tau E10 splicing.
Collapse
Affiliation(s)
- Shaohong Ding
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Jianhua Shi
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, New York 10314, USA
| | - Wei Qian
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Khalid Iqbal
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, New York 10314, USA
| | - Inge Grundke-Iqbal
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, New York 10314, USA
| | - Cheng-Xin Gong
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, New York 10314, USA
| | - Fei Liu
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, New York 10314, USA
| |
Collapse
|
31
|
Gu J, Shi J, Wu S, Jin N, Qian W, Zhou J, Iqbal IG, Iqbal K, Gong CX, Liu F. Cyclic AMP-dependent protein kinase regulates 9G8-mediated alternative splicing of tau exon 10. FEBS Lett 2012; 586:2239-44. [PMID: 22677170 DOI: 10.1016/j.febslet.2012.05.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 05/21/2012] [Indexed: 11/16/2022]
Abstract
Alternative splicing of tau exon 10 generates tau isoforms with three or four microtubule-binding repeats, named 3R- or 4R-tau. Normal adult human brain expresses equal levels of them. Imbalance of 3R-tau and 4R-tau associates with several tauopathies. Splicing factor 9G8 suppresses tau exon 10 inclusion and its function is regulated by phosphorylation. Here, we found that cyclic AMP-dependent protein kinase (PKA) phosphorylated 9G8. The catalytic subunits α and β of PKA interacted with 9G8, and activation of PKA enhanced the interaction. Up-regulation of PKA activity prevented 9G8 from inhibition of tau exon 10 inclusion. These findings provide novel insights into the regulation of tau exon 10 splicing and further our understanding of neurodegeneration associated with dysregulation of tau exon 10 splicing.
Collapse
Affiliation(s)
- Jianlan Gu
- Department of Biochemistry and Molecular Biology, Medical School, Soochow University, 199 Renai Road, Soochow, Jiangsu 215123, China
| | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Anderson ES, Lin CH, Xiao X, Stoilov P, Burge CB, Black DL. The cardiotonic steroid digitoxin regulates alternative splicing through depletion of the splicing factors SRSF3 and TRA2B. RNA (NEW YORK, N.Y.) 2012; 18:1041-9. [PMID: 22456266 PMCID: PMC3334691 DOI: 10.1261/rna.032912.112] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 02/24/2012] [Indexed: 05/24/2023]
Abstract
Modulation of alternative pre-mRNA splicing is a potential approach to therapeutic targeting for a variety of human diseases. We investigated the mechanism by which digitoxin, a member of the cardiotonic steroid class of drugs, regulates alternative splicing. Transcriptome-wide analysis identified a large set of alternative splicing events that change after digitoxin treatment. Within and adjacent to these regulated exons, we identified enrichment of potential binding sites for the splicing factors SRp20 (SRSF3/SFRS3) and Tra2-β (SFRS10/TRA2B). We further find that both of these proteins are depleted from cells by digitoxin treatment. Characterization of SRp20 and Tra2-β splicing targets revealed that many, but not all, digitoxin-induced splicing changes can be attributed to the depletion of one or both of these factors. Re-expression of SRp20 or Tra2-β after digitoxin treatment restores normal splicing of their targets, indicating that the digitoxin effect is directly due to these factors. These results demonstrate that cardiotonic steroids, long prescribed in the clinical treatment of heart failure, have broad effects on the cellular transcriptome through these and likely other RNA binding proteins. The approach described here can be used to identify targets of other potential therapeutics that act as alternative splicing modulators.
Collapse
Affiliation(s)
- Erik S. Anderson
- Molecular Biology Interdepartmental Graduate Program
- Medical Scientist Training Program
| | - Chia-Ho Lin
- Microbiology, Immunology and Molecular Genetics
- Howard Hughes Medical Institute
| | - Xinshu Xiao
- Department of Integrative Biology and Physiology
- Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
| | - Peter Stoilov
- Department of Biochemistry, West Virginia University, Morgantown, West Virginia 26506, USA
| | - Christopher B. Burge
- Department of Biology, Massachusetts Institute of Technology, Boston, Massachusetts 02139, USA
| | - Douglas L. Black
- Microbiology, Immunology and Molecular Genetics
- Howard Hughes Medical Institute
- Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
| |
Collapse
|
33
|
Abstract
Tau is a microtubule-associated protein that fulfills several functions critical for neuronal formation and health. Tau discharges its functions by producing multiple isoforms via regulated alternative splicing. These isoforms modulate tau function in normal brain by altering the domains of the protein, thereby influencing its localization, conformation, and post-translational modifications and hence its availability and affinity for microtubules and other ligands. Disturbances in tau expression result in disruption of the neuronal cytoskeleton and formation of tau structures (neurofibrillary tangles) found in brains of dementia sufferers. More specifically, aberrations in tau splicing regulation directly cause several neurodegenerative diseases, which lead to dementia. In this review, I present our cumulative knowledge of tau splicing regulation in connection with neurodegeneration and also briefly go over the still-extensive list of questions that are connected to tau (dys)function.
Collapse
Affiliation(s)
- Athena Andreadis
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA.
| |
Collapse
|
34
|
Ray P, Kar A, Fushimi K, Havlioglu N, Chen X, Wu JY. PSF suppresses tau exon 10 inclusion by interacting with a stem-loop structure downstream of exon 10. J Mol Neurosci 2011; 45:453-66. [PMID: 21881826 DOI: 10.1007/s12031-011-9634-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 08/17/2011] [Indexed: 01/24/2023]
Abstract
Microtubule binding protein Tau has been implicated in a wide range of neurodegenerative disorders collectively classified as tauopathies. Exon 10 of the human tau gene, which codes for a microtubule binding repeat region, is alternatively spliced to form Tau protein isoforms containing either four or three microtubule binding repeats, Tau4R and Tau3R, respectively. The levels of different Tau splicing isoforms are fine-tuned by alternative splicing with the ratio of Tau4R/Tau3R maintained approximately at one in adult neurons. Mutations that disrupt tau exon 10 splicing regulation cause an imbalance of different tau splicing isoforms and have been associated with tauopathy. To search for factors interacting with tau pre-messenger RNA (pre-mRNA) and regulating tau exon 10 alternative splicing, we performed a yeast RNA-protein interaction screen and identified polypyrimidine tract binding protein associated splicing factor (PSF) as a candidate tau exon 10 splicing regulator. UV crosslinking experiments show that PSF binds to the stem-loop structure at the 5' splice site downstream of tau exon 10. This PSF-interacting RNA element is distinct from known PSF binding sites previously identified in other genes. Overexpression of PSF promotes tau exon 10 exclusion, whereas down-regulation of the endogenous PSF facilitates exon 10 inclusion. Immunostaining shows that PSF is expressed in the human brain regions affected by tauopathy. Our data reveal a new player in tau exon 10 alternative splicing regulation and uncover a previously unknown mechanism of PSF in regulating tau pre-mRNA splicing.
Collapse
Affiliation(s)
- Payal Ray
- Department of Neurology, Lurie Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | | | | | | | | | | |
Collapse
|
35
|
van Abel D, Hölzel DR, Jain S, Lun FMF, Zheng YWL, Chen EZ, Sun H, Chiu RWK, Lo YMD, van Dijk M, Oudejans CBM. SFRS7-mediated splicing of tau exon 10 is directly regulated by STOX1A in glial cells. PLoS One 2011; 6:e21994. [PMID: 21755018 PMCID: PMC3130792 DOI: 10.1371/journal.pone.0021994] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Accepted: 06/10/2011] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND In this study, we performed a genome-wide search for effector genes bound by STOX1A, a winged helix transcription factor recently demonstrated to be involved in late onset Alzheimer's disease and affecting the amyloid processing pathway. METHODOLOGY/PRINCIPAL FINDINGS Our results show that out of 218 genes bound by STOX1A as identified by chromatin-immunoprecipitation followed by sequencing (ChIP-Seq), the serine/arginine-rich splicing factor 7 (SFRS7) was found to be induced, both at the mRNA and protein levels, by STOX1A after stable transfection in glial cells. The increase in SFRS7 was followed by an increase in the 4R/3R ratios of the microtubule-associated protein tau (MAPT) by differential exon 10 splicing. Secondly, STOX1A also induced expression of total tau both at the mRNA and protein levels. Upregulation of total tau expression (SFRS7-independent) and tau exon 10 splicing (SFRS7-dependent), as shown in this study to be both affected by STOX1A, is known to have implications in neurodegeneration. CONCLUSIONS Our data further supports the functional importance and central role of STOX1A in neurodegeneration.
Collapse
Affiliation(s)
- Daan van Abel
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Dennis R. Hölzel
- Department of Clinical Genetics, Section Medical Genomics, VU University Medical Center, Amsterdam, The Netherlands
| | - Shushant Jain
- Department of Clinical Genetics, Section Medical Genomics, VU University Medical Center, Amsterdam, The Netherlands
| | - Fiona M. F. Lun
- Department of Chemical Pathology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Yama W. L. Zheng
- Department of Chemical Pathology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Eric Z. Chen
- Department of Chemical Pathology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Hao Sun
- Department of Chemical Pathology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Rossa W. K. Chiu
- Department of Chemical Pathology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Y. M. Dennis Lo
- Department of Chemical Pathology, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China
| | - Marie van Dijk
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
| | - Cees B. M. Oudejans
- Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands
- * E-mail:
| |
Collapse
|
36
|
Wang Y, Wang J, Gao L, Stamm S, Andreadis A. An SRp75/hnRNPG complex interacting with hnRNPE2 regulates the 5' splice site of tau exon 10, whose misregulation causes frontotemporal dementia. Gene 2011; 485:130-8. [PMID: 21723381 DOI: 10.1016/j.gene.2011.06.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 06/09/2011] [Accepted: 06/11/2011] [Indexed: 01/14/2023]
Abstract
Tau is a neuronal-specific microtubule-associated protein that plays an important role in establishing neuronal polarity and maintaining the axonal cytoskeleton. Aggregated tau is the major component of neurofibrillary tangles (NFTs), structures present in the brains of people affected by neurodegenerative diseases called tauopathies. Tauopathies include Alzheimer's disease (AD), frontotemporal dementia with Parkinsonism (FTDP-17), the early onset dementia observed in Down syndrome (DS; trisomy 21) and the dementia component of myotonic dystrophy type 1 (DM1). Splicing misregulation of adult-specific exon 10, which codes for a microtubule binding domain, results in expression of abnormal ratios of tau isoforms, leading to FTDP-17. Positions 3 to 19 of the intron downstream of exon 10 define a hotspot of splicing regulation: the region diverges between humans and rodents, and point mutations within it result in tauopathies. In this study, we investigated three regulators of exon 10 splicing: serine/arginine-rich protein SRp75 and heterogeneous nuclear ribonucleoproteins hnRNPG and hnRNPE2. SRp75 and hnRNPG inhibit splicing of exon 10 whereas hnRNPE2 activates it. Using co-transfections, co-immunoprecipitations and RNAi we discovered that SRp75 binds to the proximal downstream intron of tau exon 10 at the FTDP-17 hotspot region; and that hnRNPG and hnRNPE2 interact with SRp75. Thus, increased exon 10 inclusion in FTDP mutants may arise from weakened SRp75 binding. This work provides insights into the splicing regulation of the tau gene and into possible strategies for correcting the imbalance in tauopathies caused by changes in the ratio of exon 10.
Collapse
Affiliation(s)
- Yan Wang
- Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | | | | | | | | |
Collapse
|
37
|
Hsu SY, Chen YJ, Ouyang P. Pnn and SR family proteins are differentially expressed in mouse central nervous system. Histochem Cell Biol 2011; 135:361-73. [DOI: 10.1007/s00418-011-0795-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2011] [Indexed: 12/31/2022]
|
38
|
Shi J, Qian W, Yin X, Iqbal K, Grundke-Iqbal I, Gu X, Ding F, Gong CX, Liu F. Cyclic AMP-dependent protein kinase regulates the alternative splicing of tau exon 10: a mechanism involved in tau pathology of Alzheimer disease. J Biol Chem 2011; 286:14639-48. [PMID: 21367856 DOI: 10.1074/jbc.m110.204453] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hyperphosphorylation and deposition of tau into neurofibrillary tangles is a hallmark of Alzheimer disease (AD). Alternative splicing of tau exon 10 generates tau isoforms containing three or four microtubule binding repeats (3R-tau and 4R-tau), which are equally expressed in adult human brain. Dysregulation of exon 10 causes neurofibrillary degeneration. Here, we report that cyclic AMP-dependent protein kinase, PKA, phosphorylates splicing factor SRSF1, modulates its binding to tau pre-mRNA, and promotes tau exon 10 inclusion in cultured cells and in vivo in rat brain. PKA-Cα, but not PKA-Cβ, interacts with SRSF1 and elevates SRSF1-mediated tau exon 10 inclusion. In AD brain, the decreased level of PKA-Cα correlates with the increased level of 3R-tau. These findings suggest that a down-regulation of PKA dysregulates the alternative splicing of tau exon 10 and contributes to neurofibrillary degeneration in AD by causing an imbalance in 3R-tau and 4R-tau expression.
Collapse
Affiliation(s)
- Jianhua Shi
- Jiangsu Key Laboratory of Neuroregeneration, Medical School, Nantong University, Nantong, Jiangsu 226001, China
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
RNA helicase p68 (DDX5) regulates tau exon 10 splicing by modulating a stem-loop structure at the 5' splice site. Mol Cell Biol 2011; 31:1812-21. [PMID: 21343338 DOI: 10.1128/mcb.01149-10] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Regulation of tau exon 10 splicing plays an important role in tauopathy. One of the cis elements regulating tau alternative splicing is a stem-loop structure at the 5' splice site of tau exon 10. The RNA helicase(s) modulating this stem-loop structure was unknown. We searched for splicing regulators interacting with this stem-loop region using an RNA affinity pulldown-coupled mass spectrometry approach and identified DDX5/RNA helicase p68 as an activator of tau exon 10 splicing. The activity of p68 in stimulating tau exon 10 inclusion is dependent on RBM4, an intronic splicing activator. RNase H cleavage and U1 protection assays suggest that p68 promotes conformational change of the stem-loop structure, thereby increasing the access of U1snRNP to the 5' splice site of tau exon 10. This study reports the first RNA helicase interacting with a stem-loop structure at the splice site and regulating alternative splicing in a helicase-dependent manner. Our work uncovers a previously unknown function of p68 in regulating tau exon 10 splicing. Furthermore, our experiments reveal functional interaction between two splicing activators for tau exon 10, p68 binding at the stem-loop region and RBM4 interacting with the intronic splicing enhancer region.
Collapse
|
40
|
|
41
|
Wang Y, Gao L, Tse SW, Andreadis A. Heterogeneous nuclear ribonucleoprotein E3 modestly activates splicing of tau exon 10 via its proximal downstream intron, a hotspot for frontotemporal dementia mutations. Gene 2009; 451:23-31. [PMID: 19914360 DOI: 10.1016/j.gene.2009.11.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2009] [Revised: 10/23/2009] [Accepted: 11/09/2009] [Indexed: 01/20/2023]
Abstract
The microtubule-associated protein tau is important to normal neuronal activity in the mammalian nervous system. Aggregated tau is the major component of neurofibrillary tangles (NFTs), structures present in the brains of people affected by neurodegenerative diseases called tauopathies. Tauopathies include Alzheimer's disease (AD), frontotemporal dementia with Parkinsonism (FTDP) and the early-onset dementia observed in Down syndrome (DS; trisomy 21). Splicing misregulation of adult-specific exon 10 results in expression of abnormal ratios of tau isoforms, leading to FTDP. Positions +3 to +19 of the intron downstream of exon 10 define a hotspot: Point mutations in it result in tauopathies. All these mutations increase exon 10 inclusion except for mutation +19, which almost entirely excludes exon 10. To investigate the tau connection between DS and AD, we examined splicing factors located on chromosome 21 for their effect on tau exon 10. By co-transfections, co-immunoprecipitations and RNAi constructs, we discovered that one of them, hnRNPE3 (PCBP3), modestly activates splicing of exon 10 by interacting with its proximal downstream intron around position +19. These results, coupled with the developmental profile of hnRNPE3, suggest a pathogenic role for splicing factors on chromosome 21 in neurodegenerative diseases with tangles and create a connection between tau splicing and the early-onset dementia of Down syndrome.
Collapse
Affiliation(s)
- Yan Wang
- Department of Cell Biology, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA
| | | | | | | |
Collapse
|
42
|
RBM4: A multifunctional RNA-binding protein. Int J Biochem Cell Biol 2009; 41:740-3. [DOI: 10.1016/j.biocel.2008.05.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 05/05/2008] [Accepted: 05/06/2008] [Indexed: 01/26/2023]
|
43
|
Shi J, Zhang T, Zhou C, Chohan MO, Gu X, Wegiel J, Zhou J, Hwang YW, Iqbal K, Grundke-Iqbal I, Gong CX, Liu F. Increased dosage of Dyrk1A alters alternative splicing factor (ASF)-regulated alternative splicing of tau in Down syndrome. J Biol Chem 2008; 283:28660-9. [PMID: 18658135 PMCID: PMC2568927 DOI: 10.1074/jbc.m802645200] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 07/14/2008] [Indexed: 12/15/2022] Open
Abstract
Two groups of tau, 3R- and 4R-tau, are generated by alternative splicing of tau exon 10. Normal adult human brain expresses equal levels of them. Disruption of the physiological balance is a common feature of several tauopathies. Very early in their life, individuals with Down syndrome (DS) develop Alzheimer-type tau pathology, the molecular basis for which is not fully understood. Here, we demonstrate that Dyrk1A, a kinase encoded by a gene in the DS critical region, phosphorylates alternative splicing factor (ASF) at Ser-227, Ser-234, and Ser-238, driving it into nuclear speckles and preventing it from facilitating tau exon 10 inclusion. The increased dosage of Dyrk1A in DS brain due to trisomy of chromosome 21 correlates to an increase in 3R-tau level, which on abnormal hyperphosphorylation and aggregation of tau results in neurofibrillary degeneration. Imbalance of 3R- and 4R-tau in DS brain by Dyrk1A-induced dysregulation of alternative splicing factor-mediated alternative splicing of tau exon 10 represents a novel mechanism of neurofibrillary degeneration and may help explain early onset tauopathy in individuals with DS.
Collapse
Affiliation(s)
- Jianhua Shi
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, P. R. China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
A high-throughput screening strategy identifies cardiotonic steroids as alternative splicing modulators. Proc Natl Acad Sci U S A 2008; 105:11218-23. [PMID: 18678901 DOI: 10.1073/pnas.0801661105] [Citation(s) in RCA: 107] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Alternative splicing has emerged as a promising therapeutic target in a number of human disorders. However, the discovery of compounds that target the splicing reaction has been hindered by the lack of suitable high-throughput screening assays. Conversely, the effects of known drugs on the splicing reaction are mostly unclear and not routinely assessed. We have developed a two-color fluorescent reporter for cellular assays of exon inclusion that can accommodate nearly any cassette exon and minimizes interfering effects from changes in transcription and translation. We used microtubule-associated protein tau (MAPT) exon 10, whose missplicing causes frontotemporal dementia, to test the reporter in screening libraries of known bioactive compounds. These screens yielded several compounds that alter the splicing of the exon, both in the reporter and in the endogenous MAPT mRNA. One compound, digoxin, has long been used in the treatment of heart failure, but was not known to modulate splicing. The positive compounds target different signal transduction pathways, and microarray analysis shows that each compound affects the splicing of a different set of exons in addition to MAPT exon 10. Our results identify currently prescribed cardiotonic steroids as modulators of alternative splicing and demonstrate the feasibility of screening for drugs that alter exon inclusion.
Collapse
|
45
|
Liu F, Gong CX. Tau exon 10 alternative splicing and tauopathies. Mol Neurodegener 2008; 3:8. [PMID: 18616804 PMCID: PMC2483273 DOI: 10.1186/1750-1326-3-8] [Citation(s) in RCA: 212] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 07/10/2008] [Indexed: 01/27/2023] Open
Abstract
Abnormalities of microtubule-associated protein tau play a central role in neurofibrillary degeneration in several neurodegenerative disorders that collectively called tauopathies. Six isoforms of tau are expressed in adult human brain, which result from alternative splicing of pre-mRNA generated from a single tau gene. Alternative splicing of tau exon 10 results in tau isoforms containing either three or four microtubule-binding repeats (3R-tau and 4R-tau, respectively). Approximately equal levels of 3R-tau and 4R-tau are expressed in normal adult human brain, but the 3R-tau/4R-tau ratio is altered in the brains in several tauopathies. Discovery of silence mutations and intronic mutations of tau gene in some individuals with frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17), which only disrupt tau exon 10 splicing but do not alter tau's primary sequence, demonstrates that dysregulation of tau exon 10 alternative splicing and consequently of 3R-tau/4R-tau balance is sufficient to cause neurodegeneration and dementia. Here, we review the gene structure, transcripts and protein isoforms of tau, followed by the regulation of exon 10 splicing that determines the expression of 3R-tau or 4R-tau. Finally, dysregulation of exon 10 splicing of tau in several tauopathies is discussed. Understanding the molecular mechanisms by which tau exon 10 splicing is regulated and how it is disrupted in tauopathies will provide new insight into the mechanisms of these tauopathies and help identify new therapeutic targets to treat these disorders.
Collapse
Affiliation(s)
- Fei Liu
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 10314, USA.
| | | |
Collapse
|
46
|
Abstract
Conventional gene therapy has focused largely on gene replacement in target cells. However, progress from basic research to the clinic has been slow for reasons relating principally to the challenges of heterologous DNA delivery and regulation in vivo. Alternative approaches targeting RNA have the potential to circumvent some of these difficulties, particularly as the active therapeutic molecules are usually short oligonucleotides and the target gene transcript is under endogenous regulation. RNA-based strategies offer a series of novel therapeutic applications, including altered processing of the target pre-mRNA transcript, reprogramming of genetic defects through mRNA repair, and the targeted silencing of allele- or isoform-specific gene transcripts. This review examines the potential of RNA therapeutics, focusing on antisense oligonucleotide modification of pre-mRNA splicing, methods for pre-mRNA trans-splicing, and the isoform- and allele-specific applications of RNA interference.
Collapse
Affiliation(s)
- Matthew Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, United Kingdom.
| | | | | |
Collapse
|