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Ma HL, Bizet M, Soares Da Costa C, Murisier F, de Bony EJ, Wang MK, Yoshimi A, Lin KT, Riching KM, Wang X, Beckman JI, Arya S, Droin N, Calonne E, Hassabi B, Zhang QY, Li A, Putmans P, Malbec L, Hubert C, Lan J, Mies F, Yang Y, Solary E, Daniels DL, Gupta YK, Deplus R, Abdel-Wahab O, Yang YG, Fuks F. SRSF2 plays an unexpected role as reader of m 5C on mRNA, linking epitranscriptomics to cancer. Mol Cell 2023; 83:4239-4254.e10. [PMID: 38065062 PMCID: PMC11090011 DOI: 10.1016/j.molcel.2023.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/06/2023] [Accepted: 11/03/2023] [Indexed: 12/18/2023]
Abstract
A common mRNA modification is 5-methylcytosine (m5C), whose role in gene-transcript processing and cancer remains unclear. Here, we identify serine/arginine-rich splicing factor 2 (SRSF2) as a reader of m5C and impaired SRSF2 m5C binding as a potential contributor to leukemogenesis. Structurally, we identify residues involved in m5C recognition and the impact of the prevalent leukemia-associated mutation SRSF2P95H. We show that SRSF2 binding and m5C colocalize within transcripts. Furthermore, knocking down the m5C writer NSUN2 decreases mRNA m5C, reduces SRSF2 binding, and alters RNA splicing. We also show that the SRSF2P95H mutation impairs the ability of the protein to read m5C-marked mRNA, notably reducing its binding to key leukemia-related transcripts in leukemic cells. In leukemia patients, low NSUN2 expression leads to mRNA m5C hypomethylation and, combined with SRSF2P95H, predicts poor outcomes. Altogether, we highlight an unrecognized mechanistic link between epitranscriptomics and a key oncogenesis driver.
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Affiliation(s)
- Hai-Li Ma
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Martin Bizet
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Christelle Soares Da Costa
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Frédéric Murisier
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Eric James de Bony
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Meng-Ke Wang
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics and Chinese Academy of Sciences, China National Center for Bioinformation, Beijing 100101, China
| | - Akihide Yoshimi
- Molecular Pharmacology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Kuan-Ting Lin
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | | | - Xing Wang
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics and Chinese Academy of Sciences, China National Center for Bioinformation, Beijing 100101, China
| | - John I Beckman
- Greehey Children's Cancer Research Institute, Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Shailee Arya
- Greehey Children's Cancer Research Institute, Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Nathalie Droin
- Université Paris-Saclay, INSERM U1287, and Department of Hematology, Gustave Roussy Cancer Center, Villejuif 94800, France
| | - Emilie Calonne
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Bouchra Hassabi
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Qing-Yang Zhang
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics and Chinese Academy of Sciences, China National Center for Bioinformation, Beijing 100101, China
| | - Ang Li
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics and Chinese Academy of Sciences, China National Center for Bioinformation, Beijing 100101, China
| | - Pascale Putmans
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Lionel Malbec
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Céline Hubert
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Jie Lan
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Frédérique Mies
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Ying Yang
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics and Chinese Academy of Sciences, China National Center for Bioinformation, Beijing 100101, China
| | - Eric Solary
- Université Paris-Saclay, INSERM U1287, and Department of Hematology, Gustave Roussy Cancer Center, Villejuif 94800, France
| | | | - Yogesh K Gupta
- Greehey Children's Cancer Research Institute, Department of Biochemistry and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Rachel Deplus
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium
| | - Omar Abdel-Wahab
- Molecular Pharmacology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Yun-Gui Yang
- CAS Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics and Chinese Academy of Sciences, China National Center for Bioinformation, Beijing 100101, China.
| | - François Fuks
- Laboratory of Cancer Epigenetics, Faculty of Medicine, ULB-Cancer Research Center (U-CRC), Université libre de Bruxelles (ULB), Institut Jules Bordet, Brussels 1070, Belgium.
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Jiang T, Wang L, Tang L, Zeb A, Hou Y. Identification of two short peptide motifs from serine/arginine-rich protein ribonucleic acid recognition motif-1 domain acting as splicing regulators. PeerJ 2023; 11:e16103. [PMID: 37744237 PMCID: PMC10512959 DOI: 10.7717/peerj.16103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/25/2023] [Indexed: 09/26/2023] Open
Abstract
Background Serine/arginine-rich (SR) proteins regulate pre-mRNA splicing. However, structurally similar proteins often behave differently in splicing regulation and the underlying mechanisms are largely unknown. Here, using SMN1/2 minigenes we extensively analyzed four SR proteins, SRSF1/5/6/9. Methods In this study, the effects of these proteins on SMN1/2 exon 7 splicing when tethered at either intron 6 or 7 were evaluated using an MS2-tethering assay. Deletion analysis in four SR proteins and co-overexpression analysis were performed. Results Splicing outcomes varied among all four SR proteins, SRSF1 and SRSF5 function the same at the two sites, acting as repressor and stimulator, respectively; while SRSF6 and SRSF9 promote exon 7 inclusion at only one site. Further, the key domains of each SR proteins were investigated, which identified a potent inhibitory nonapeptide in the C-terminus of SRSF1/9 ribonucleic acid recognition motif-1 (RRM1) and a potent stimulatory heptapeptide at the N-terminus of SRSF5/6 RRM1. Conclusion The insight of the four SR proteins and their domains in affecting SMN gene splicing brings a new perspective on the modes of action of SR proteins; and the functional peptides obtained here offers new ideas for developing splice switching-related therapies.
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Affiliation(s)
- Tao Jiang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
- Department of Rehabilitation, Southwest Hospital, Third Military Medical University Army Medical University, Chongqing, China
| | - Li Wang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
| | - Liang Tang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
| | - Azhar Zeb
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
| | - Yanjun Hou
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, NanJing, China
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Jung H, Park HJ, Jo SH, Lee A, Lee HJ, Kim HS, Jung C, Cho HS. Nuclear OsFKBP20-1b maintains SR34 stability and promotes the splicing of retained introns upon ABA exposure in rice. THE NEW PHYTOLOGIST 2023; 238:2476-2494. [PMID: 36942934 DOI: 10.1111/nph.18892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/16/2023] [Indexed: 05/19/2023]
Abstract
Alternative splicing (AS) is a critical means by which plants respond to changes in the environment, but few splicing factors contributing to AS have been reported and functionally characterized in rice (Oryza sativa L.). Here, we explored the function and molecular mechanism of the spliceosome-associated protein OsFKBP20-1b during AS. We determined the AS landscape of wild-type and osfkbp20-1b knockout plants upon abscisic acid (ABA) treatment by transcriptome deep sequencing. To capture the dynamics of translating intron-containing mRNAs, we blocked transcription with cordycepin and performed polysome profiling. We also analyzed whether OsFKBP20-1b and the splicing factors OsSR34 and OsSR45 function together in AS using protoplast transfection assays. We show that OsFKBP20-1b interacts with OsSR34 and regulates its stability, suggesting a role as a chaperone-like protein in the spliceosome. OsFKBP20-1b facilitates the splicing of mRNAs with retained introns after ABA treatment; some of these mRNAs are translatable and encode functional transcriptional regulators of stress-responsive genes. In addition, interacting proteins, OsSR34 and OsSR45, regulate the splicing of the same retained introns as OsFKBP20-1b after ABA treatment. Our findings reveal that spliceosome-associated immunophilin functions in alternative RNA splicing in rice by positively regulating the splicing of retained introns to limit ABA response.
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Affiliation(s)
- Haemyeong Jung
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Hyun Ji Park
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
| | - Seung Hee Jo
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Areum Lee
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Hyo-Jun Lee
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Functional Genomics, KRIBB School of Bioscience, UST, Daejeon, 34113, South Korea
| | - Hyun-Soon Kim
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
| | - Choonkyun Jung
- Department of International Agricultural Technology and Crop Biotechnology Institute/Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, South Korea
- Department of Agriculture, Forestry, and Bioresources and Integrated Major in Global Smart Farm, College of Agriculture and Life Sciences, Seoul National University, Seoul, 08826, South Korea
| | - Hye Sun Cho
- Plant Systems Engineering Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, 34141, South Korea
- Department of Biosystems and Bioengineering, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon, 34113, South Korea
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Li X, Fang J, Tao X, Xia J, Cheng B, Wang Y. Splice site m 6A methylation prevents binding of DGCR8 to suppress KRT4 pre-mRNA splicing in oral squamous cell carcinoma. PeerJ 2023; 11:e14824. [PMID: 36811004 PMCID: PMC9939020 DOI: 10.7717/peerj.14824] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/08/2023] [Indexed: 02/18/2023] Open
Abstract
Oral squamous cell carcinoma (OSCC) is the 11th most prevalent tumor worldwide. Despite advantages of therapeutic approaches, the 5-year survival rate of patients with OSCC is less than 50%. It is urgent to elucidate mechanisms underlying OSCC progression for developing novel treatment strategies. Our recent study has revealed that Keratin 4 (KRT4) suppresses OSCC development, which is downregulated in OSCC. Nevertheless, the mechanism downregulating KRT4 in OSCC remains unknown. In this study, touchdown PCR was utilized to detect KRT4 pre-mRNA splicing, while m6A RNA methylation was identified by methylated RNA immunoprecipitation (MeRIP). Besides, RNA immunoprecipitation (RIP) was used to determine RNA-protein interaction. Herein, this study indicated that intron splicing of KRT4 pre-mRNA was suppressed in OSCC. Mechanistically, m6A methylation of exon-intron boundaries prevented intron splicing of KRT4 pre-mRNA in OSCC. Besides, m6A methylation suppressed the binding of splice factor DGCR8 microprocessor complex subunit (DGCR8) to exon-intron boundaries in KRT4 pre-mRNA to prohibit intron splicing of KRT4 pre-mRNA in OSCC. These findings revealed the mechanism downregulating KRT4 in OSCC and provided potential therapeutic targets for OSCC.
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Affiliation(s)
- Xiaoxu Li
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Juan Fang
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Xiaoan Tao
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Juan Xia
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Bin Cheng
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yun Wang
- Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
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Liu L, Lv Z, Wang M, Zhang D, Liu D, Zhu F. HBV Enhances Sorafenib Resistance in Hepatocellular Carcinoma by Reducing Ferroptosis via SRSF2-Mediated Abnormal PCLAF Splicing. Int J Mol Sci 2023; 24:ijms24043263. [PMID: 36834680 PMCID: PMC9967099 DOI: 10.3390/ijms24043263] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/02/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is one of the most lethal human cancers. Hepatitis B virus (HBV) infection accounts for nearly 50% of HCC cases. Recent studies indicate that HBV infection induces resistance to sorafenib, the first-line systemic treatment for advanced HCC for more than a decade, from 2007 to 2020. Our previous research shows that variant 1 (tv1) of proliferating cell nuclear antigen clamp-associated factor (PCLAF), overexpressed in HCC, protects against doxorubicin-induced apoptosis. However, there are no reports on the relevance of PCLAF in sorafenib resistance in HBV-related HCC. In this article, we found that PCLAF levels were higher in HBV-related HCC than in non-virus-related HCC using bioinformatics analysis. Immunohistochemistry (IHC) staining of clinical samples and the splicing reporter minigene assay using HCC cells revealed that PCLAF tv1 was elevated by HBV. Furthermore, HBV promoted the splicing of PCLAF tv1 by downregulating serine/arginine-rich splicing factor 2 (SRSF2), which hindered the inclusion of PCLAF exon 3 through a putative cis-element (116-123), "GATTCCTG". The CCK-8 assay showed that HBV decreased cell susceptibility to sorafenib through SRSF2/PCLAF tv1. HBV reduced ferroptosis by decreasing intracellular Fe2+ levels and activating GPX4 expression via the SRSF2/PCLAF tv1 axis, according to a mechanism study. Suppressed ferroptosis, on the other hand, contributed to HBV-mediated sorafenib resistance through SRSF2/PCLAF tv1. These data suggested that HBV regulated PCLAF abnormal alternative splicing by suppressing SRSF2. HBV caused sorafenib resistance by reducing ferroptosis via the SRSF2/PCLAF tv1 axis. As a result, the SRSF2/PCLAF tv1 axis may be a prospective molecular therapeutic target in HBV-related HCC, as well as a predictor of sorafenib resistance. The inhibition of the SRSF2/PCLAF tv1 axis may be crucial in the emergence of systemic chemotherapy resistance in HBV-associated HCC.
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Affiliation(s)
| | | | | | | | | | - Fan Zhu
- Correspondence: ; Tel.: +86-189-4290-0238
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Ruiz-Gabarre D, Carnero-Espejo A, Ávila J, García-Escudero V. What's in a Gene? The Outstanding Diversity of MAPT. Cells 2022; 11:840. [PMID: 35269461 PMCID: PMC8909800 DOI: 10.3390/cells11050840] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 02/25/2022] [Accepted: 02/27/2022] [Indexed: 02/04/2023] Open
Abstract
Tau protein is a microtubule-associated protein encoded by the MAPT gene that carries out a myriad of physiological functions and has been linked to certain pathologies collectively termed tauopathies, including Alzheimer's disease, frontotemporal dementia, Huntington's disease, progressive supranuclear palsy, etc. Alternative splicing is a physiological process by which cells generate several transcripts from one single gene and may in turn give rise to different proteins from the same gene. MAPT transcripts have been proven to be subjected to alternative splicing, generating six main isoforms in the central nervous system. Research throughout the years has demonstrated that the splicing landscape of the MAPT gene is far more complex than that, including at least exon skipping events, the use of 3' and 5' alternative splice sites and, as has been recently discovered, also intron retention. In addition, MAPT alternative splicing has been showed to be regulated spatially and developmentally, further evidencing the complexity of the gene's splicing regulation. It is unclear what would drive the need for the existence of so many isoforms encoded by the same gene, but a wide range of functions have been ascribed to these Tau isoforms, both in physiology and pathology. In this review we offer a comprehensive up-to-date exploration of the mechanisms leading to the outstanding diversity of isoforms expressed from the MAPT gene and the functions in which such isoforms are involved, including their potential role in the onset and development of tauopathies such as Alzheimer's disease.
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Affiliation(s)
- Daniel Ruiz-Gabarre
- Anatomy, Histology and Neuroscience Department, School of Medicine, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain; (D.R.-G.); (A.C.-E.)
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC), 28049 Madrid, Spain
- Graduate Program in Neuroscience, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
| | - Almudena Carnero-Espejo
- Anatomy, Histology and Neuroscience Department, School of Medicine, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain; (D.R.-G.); (A.C.-E.)
- Graduate Program in Neuroscience, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
| | - Jesús Ávila
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC), 28049 Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, 28031 Madrid, Spain
| | - Vega García-Escudero
- Anatomy, Histology and Neuroscience Department, School of Medicine, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain; (D.R.-G.); (A.C.-E.)
- Centro de Biología Molecular Severo Ochoa (UAM-CSIC), 28049 Madrid, Spain
- Graduate Program in Neuroscience, Universidad Autónoma de Madrid (UAM), 28029 Madrid, Spain
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Neuronal Pnn Deficiency Increases Oxidative Stress and Exacerbates Cerebral Ischemia/Reperfusion Injury in Mice. Antioxidants (Basel) 2022; 11:antiox11030466. [PMID: 35326115 PMCID: PMC8944488 DOI: 10.3390/antiox11030466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 02/23/2022] [Accepted: 02/25/2022] [Indexed: 12/10/2022] Open
Abstract
Cerebral stroke remains one of the leading causes of death worldwide. Ischemic stroke caused by the sudden loss of blood flow in brain is the major type of cerebral stroke. In addition to necrotic cell death in the ischemic core region, neuronal apoptosis is usually observed in the ischemic penumbra. Pnn, a multi-functional protein, participates in cellular proliferation, migration, differentiation, apoptosis as well as cell–cell interaction through its abilities in regulating gene transcription and mRNA processing. Our recent studies have demonstrated that Pnn has a cell type-specific distribution manner in neural cells under ischemic injury and plays a protective role in astrocytes against ischemic stress. In this study, we generated an inducible neuron-specific Pnn deficiency mouse model to further investigate the physiological role of Pnn in neurons. To directly examine the role of neuronal Pnn in ischemic stress, four weeks after induction of Pnn deficiency in neurons, middle cerebral artery occlusion (MCAO) was applied to induce cerebral ischemia/reperfusion in mice. In the cerebrum and hippocampus with neuronal Pnn depletion, the expression of SRSF2, a mRNA splicing regulator, was increased, while the expression of SRSF1, a functional antagonist of SRSF2, was reduced. Expression levels of ROS generators (NOX-1 and NOX-2) and antioxidant proteins (GR, HO-1, NQO-1) were upregulated in brain tissue with loss of neuronal Pnn, echoing an increase in oxidized proteins in cortical and hippocampal neurons. Furthermore, the expression of DNA damage marker, p53bp1, was found in the choroid plexus of mice with neuronal Pnn depletion. In mice with MCAO, compared to wild type mice, both increased cerebral infarcted area and elevated expressions of proapoptotic proteins were found in mice with neuronal Pnn depletion. In conclusion, Pnn deficiency increases oxidative stress in neurons and exacerbates cerebral ischemia/reperfusion injury in mice.
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8
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García-Escudero V, Ruiz-Gabarre D, Gargini R, Pérez M, García E, Cuadros R, Hernández IH, Cabrera JR, García-Escudero R, Lucas JJ, Hernández F, Ávila J. A new non-aggregative splicing isoform of human Tau is decreased in Alzheimer's disease. Acta Neuropathol 2021; 142:159-177. [PMID: 33934221 PMCID: PMC8217066 DOI: 10.1007/s00401-021-02317-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 04/21/2021] [Accepted: 04/22/2021] [Indexed: 12/11/2022]
Abstract
Tauopathies, including Alzheimer's disease (AD) and frontotemporal lobar degeneration with Tau pathology (FTLD-tau), are a group of neurodegenerative disorders characterized by Tau hyperphosphorylation. Post-translational modifications of Tau such as phosphorylation and truncation have been demonstrated to be an essential step in the molecular pathogenesis of these tauopathies. In this work, we demonstrate the existence of a new, human-specific truncated form of Tau generated by intron 12 retention in human neuroblastoma cells and, to a higher extent, in human RNA brain samples, using qPCR and further confirming the results on a larger database of human RNA-seq samples. Diminished protein levels of this new Tau isoform are found by Westernblotting in Alzheimer's patients' brains (Braak I n = 3; Braak II n = 6, Braak III n = 3, Braak IV n = 1, and Braak V n = 10, Braak VI n = 8) with respect to non-demented control subjects (n = 9), suggesting that the lack of this truncated isoform may play an important role in the pathology. This new Tau isoform exhibits similar post-transcriptional modifications by phosphorylation and affinity for microtubule binding, but more interestingly, is less prone to aggregate than other Tau isoforms. Finally, we present evidence suggesting this new Tau isoform could be linked to the inhibition of GSK3β, which would mediate intron 12 retention by modulating the serine/arginine rich splicing factor 2 (SRSF2). Our results show the existence of an important new isoform of Tau and suggest that further research on this less aggregation-prone Tau may help to develop future therapies for Alzheimer's disease and other tauopathies.
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Affiliation(s)
- Vega García-Escudero
- Departamento de Anatomía, Histología y Neurociencia, School of Medicine, Autonoma de Madrid University (UAM), Arzobispo Morcillo, 4, 28029, Madrid, Spain
- Graduate Program in Neuroscience, Autonoma de Madrid University (UAM), Arzobispo Morcillo, 4, 28029, Madrid, Spain
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain
| | - Daniel Ruiz-Gabarre
- Departamento de Anatomía, Histología y Neurociencia, School of Medicine, Autonoma de Madrid University (UAM), Arzobispo Morcillo, 4, 28029, Madrid, Spain
- Graduate Program in Neuroscience, Autonoma de Madrid University (UAM), Arzobispo Morcillo, 4, 28029, Madrid, Spain
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain
| | - Ricardo Gargini
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain
- Neurooncology Unit, Instituto de Salud Carlos III-UFIEC, 28220, Madrid, Spain
| | - Mar Pérez
- Departamento de Anatomía, Histología y Neurociencia, School of Medicine, Autonoma de Madrid University (UAM), Arzobispo Morcillo, 4, 28029, Madrid, Spain
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain
| | - Esther García
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain
| | - Raquel Cuadros
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain
| | - Ivó H Hernández
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain
| | - Jorge R Cabrera
- Unidad de Investigación, Fundación Hospital de Jove, 33290, Gijón, Spain
| | - Ramón García-Escudero
- Molecular Oncology Unit, CIEMAT, Ave Complutense, 40, 28040, Madrid, Spain
- Hospital 12 Octubre Research Institute/CIEMAT, Madrid, Spain
- Centro de Investigación Biomédica en Red de Cancer (CIBERONC), Valderrebollo, 5, 28031, Madrid, Spain
| | - José J Lucas
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, 28031, Madrid, Spain
| | - Félix Hernández
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, 28031, Madrid, Spain
| | - Jesús Ávila
- Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM). Nicolás Cabrera, 1. Cantoblanco, 28049, Madrid, Spain.
- Networking Research Center on Neurodegenerative Diseases (CIBERNED), Instituto de Salud Carlos III, 28031, Madrid, Spain.
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9
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Li K, Wang Z. Splicing factor SRSF2-centric gene regulation. Int J Biol Sci 2021; 17:1708-1715. [PMID: 33994855 PMCID: PMC8120470 DOI: 10.7150/ijbs.58888] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/04/2021] [Indexed: 01/14/2023] Open
Abstract
Serine/arginine-rich splicing factor 2 (SRSF2) is a splicing factor that is widely expressed in a variety of mammalian cell types. Increasing evidence has confirmed that SRSF2 plays vital roles in a number of biological and pathological processes. Therefore, it is important to understand how its expression is regulated, and how it regulates the expression of its target genes. Recently, we found that SRSF2 expression could be upregulated by herpes simplex virus-1 (HSV-1) infection, and that altered SRSF2 expression, in turn, epigenetically regulates the transcription of HSV-1 genes. Further studies on T cell exhaustion demonstrated that upregulated SRSF2 in exhausted T cells elevated the levels of multiple immune checkpoint molecules by associating with the acyl-transferases, P300 and CBP, and by altering histone modification near the transcription start sites of these genes, thereby influencing signal transducer and activator of transcription 3 binding to these gene promoters. These findings suggest that SRSF2 acts as an important sensor and effector during disease progression. Here, we discuss the molecules that regulate SRSF2 gene expression and their associated mechanisms, and the mechanisms via which SRSF2 regulates the expression of target genes, thus providing novel insights into the central role of SRSF2 in gene regulation.
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Affiliation(s)
- Kun Li
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan 250014, China
| | - Ziqiang Wang
- Department of Nuclear Medicine, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan 250014, China.,Biomedical Sciences College & Shandong Medicinal Biotechnology Centre, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan 250062, China
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10
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Clinical presentation and differential splicing of SRSF2, U2AF1 and SF3B1 mutations in patients with acute myeloid leukemia. Leukemia 2020; 34:2621-2634. [PMID: 32358566 DOI: 10.1038/s41375-020-0839-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 04/06/2020] [Accepted: 04/14/2020] [Indexed: 12/30/2022]
Abstract
Previous studies demonstrated that splicing factor mutations are recurrent events in hematopoietic malignancies with both clinical and functional implications. However, their aberrant splicing patterns in acute myeloid leukemia remain largely unexplored. In this study, we characterized mutations in SRSF2, U2AF1, and SF3B1, the most commonly mutated splicing factors. In our clinical analysis of 2678 patients, splicing factor mutations showed inferior relapse-free and overall survival, however, these mutations did not represent independent prognostic markers. RNA-sequencing of 246 and independent validation in 177 patients revealed an isoform expression profile which is highly characteristic for each individual mutation, with several isoforms showing a strong dysregulation. By establishing a custom differential splice junction usage pipeline, we accurately detected aberrant splicing in splicing factor mutated samples. A large proportion of differentially used junctions were novel, including several junctions in leukemia-associated genes. In SRSF2(P95H) mutants, we further explored the possibility of a cascading effect through the dysregulation of the splicing pathway. Furthermore, we observed a validated impact on overall survival for two junctions overused in SRSF2(P95H) mutants. We conclude that splicing factor mutations do not represent independent prognostic markers. However, they do have genome-wide consequences on gene splicing leading to dysregulated isoform expression of several genes.
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11
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Moon H, Jang HN, Liu Y, Choi N, Oh J, Ha J, Kim HH, Zheng X, Shen H. RRM but not the Asp/Glu domain of hnRNP C1/C2 is required for splicing regulation of Ron exon 11 pre-mRNA. BMB Rep 2019. [PMID: 31401978 PMCID: PMC6889891 DOI: 10.5483/bmbrep.2019.52.11.080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
Abstract
The Ron proto-oncogene is a human receptor for macrophage-stimulating protein (MSP). The exclusion of exon 11 in alternative splicing generates ΔRON protein that is constitutively activated. Heterogenous ribonucleaoprotein (hnRNP) C1/C2 is one of the most abundant proteins in cells. In this manuscript, we showed that both hnRNP C1 and C2 promoted exon 11 inclusion of Ron pre-mRNA and that hnRNP C1 and hnRNP C2 functioned independently but not cooperatively. Moreover, hnRNP C1 stimulated exon 11 splicing through intron 10 activation but not through intron 11 splicing. Furthermore, we showed that, whereas the RRM domain was required for hnRNP C1 function, the Asp/Glu domain was not. In conclusion, hnRNP C1/C2 promoted exon 11 splicing independently by stimulating intron 10 splicing through RRM but not through the Asp/Glu domain.
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Affiliation(s)
- Heegyum Moon
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Ha Na Jang
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Yongchao Liu
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Namjeong Choi
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Jagyeong Oh
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Jiyeon Ha
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Hyeon Ho Kim
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 06351, Korea
| | - Xuexiu Zheng
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - Haihong Shen
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
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12
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Activation of Cryptic 3' Splice-Sites by SRSF2 Contributes to Cassette Exon Skipping. Cells 2019; 8:cells8070696. [PMID: 31295920 PMCID: PMC6678912 DOI: 10.3390/cells8070696] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Revised: 07/05/2019] [Accepted: 07/09/2019] [Indexed: 11/21/2022] Open
Abstract
Here we show that the serine/arginine rich splicing factor 2 (SRSF2) promotes cryptic 3′ splice-site (3′AG′) usage during cassette exon exclusion in survival of motor neuron (SMN2) minigenes. Deletion of the 3′AG′ (3′AG′1), its associated branch point (BP′) and polypyrimidine tract (PPT′) sequences directs SRSF2 to promote a second 3′AG′ (3′AG′2) with less conserved associated region for intron splicing. Furthermore, deletion of both 3′AG′1 and 3′AG′2 and their associated sequences triggered usage of a third 3′AG′3 that has very weak associated sequences. Interestingly, when intron splicing was directed to the 3′AG′ cryptic splice-sites, intron splicing from the canonical 3′AG splice-site was reduced along with a decrease in cassette exon inclusion. Moreover, multiple SRSF2 binding sites within the intron are responsible for 3′AG′ activation. We conclude that SRSF2 facilitates exon exclusion by activating a cryptic 3′AG′ and inhibiting downstream intron splicing.
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