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Sun L, Liu Y, Guo X, Cui T, Wu C, Tao J, Cheng C, Chu Q, Ji C, Li X, Guo H, Liang S, Zhou H, Zhou S, Ma K, Zhang N, Wang J, Liu Y, Liu L. Acetylation-dependent regulation of core spliceosome modulates hepatocellular carcinoma cassette exons and sensitivity to PARP inhibitors. Nat Commun 2024; 15:5209. [PMID: 38890388 PMCID: PMC11189467 DOI: 10.1038/s41467-024-49573-7] [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: 06/29/2023] [Accepted: 06/09/2024] [Indexed: 06/20/2024] Open
Abstract
Despite the importance of spliceosome core components in cellular processes, their roles in cancer development, including hepatocellular carcinoma (HCC), remain poorly understood. In this study, we uncover a critical role for SmD2, a core component of the spliceosome machinery, in modulating DNA damage in HCC through its impact on BRCA1/FANC cassette exons and expression. Our findings reveal that SmD2 depletion sensitizes HCC cells to PARP inhibitors, expanding the potential therapeutic targets. We also demonstrate that SmD2 acetylation by p300 leads to its degradation, while HDAC2-mediated deacetylation stabilizes SmD2. Importantly, we show that the combination of Romidepsin and Olaparib exhibits significant therapeutic potential in multiple HCC models, highlighting the promise of targeting SmD2 acetylation and HDAC2 inhibition alongside PARP inhibitors for HCC treatment.
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Affiliation(s)
- Linmao Sun
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
- Anhui Provincial Clinical Research Center for Hepatobiliary Diseases, Hefei, 230001, Anhui, China
| | - Yufeng Liu
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
- Anhui Provincial Clinical Research Center for Hepatobiliary Diseases, Hefei, 230001, Anhui, China
| | - Xinyu Guo
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
| | - Tianming Cui
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
- Anhui Provincial Clinical Research Center for Hepatobiliary Diseases, Hefei, 230001, Anhui, China
| | - Chenghui Wu
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
| | - Jie Tao
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
| | - Cheng Cheng
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
| | - Qi Chu
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
| | - Changyong Ji
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
| | - Xianying Li
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
| | - Hongrui Guo
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
- Anhui Provincial Clinical Research Center for Hepatobiliary Diseases, Hefei, 230001, Anhui, China
| | - Shuhang Liang
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
- Department of Gastrointestinal Surgery, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China
| | - Huanran Zhou
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
- Department of Endocrinology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, China
| | - Shuo Zhou
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
| | - Kun Ma
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
- Anhui Provincial Clinical Research Center for Hepatobiliary Diseases, Hefei, 230001, Anhui, China
| | - Ning Zhang
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China
| | - Jiabei Wang
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China.
- Anhui Provincial Clinical Research Center for Hepatobiliary Diseases, Hefei, 230001, Anhui, China.
| | - Yao Liu
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China.
- Anhui Provincial Clinical Research Center for Hepatobiliary Diseases, Hefei, 230001, Anhui, China.
| | - Lianxin Liu
- Department of Hepatobiliary Surgery, Centre for Leading Medicine and Advanced Technologies of IHM, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230001, Anhui, China.
- Anhui Provincial Key Laboratory of Hepatopancreatobiliary Surgery, Hefei, 230001, Anhui, China.
- Anhui Provincial Clinical Research Center for Hepatobiliary Diseases, Hefei, 230001, Anhui, China.
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Leow DMK, Ng YK, Wang LC, Koh HW, Zhao T, Khong ZJ, Tabaglio T, Narayanan G, Giadone RM, Sobota RM, Ng SY, Teo AKK, Parson SH, Rubin LL, Ong WY, Darras BT, Yeo CJ. Hepatocyte-intrinsic SMN deficiency drives metabolic dysfunction and liver steatosis in spinal muscular atrophy. J Clin Invest 2024; 134:e173702. [PMID: 38722695 PMCID: PMC11178536 DOI: 10.1172/jci173702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 04/25/2024] [Indexed: 06/18/2024] Open
Abstract
Spinal Muscular Atrophy (SMA) is typically characterized as a motor neuron disease, but extra-neuronal phenotypes are present in almost every organ in severely affected patients and animal models. Extra-neuronal phenotypes were previously underappreciated as patients with severe SMA phenotypes usually died in infancy; however, with current treatments for motor neurons increasing patient lifespan, impaired function of peripheral organs may develop into significant future comorbidities and lead to new treatment-modified phenotypes. Fatty liver is seen in SMA animal models , but generalizability to patients and whether this is due to hepatocyte-intrinsic Survival Motor Neuron (SMN) protein deficiency and/or subsequent to skeletal muscle denervation is unknown. If liver pathology in SMA is SMN-dependent and hepatocyte-intrinsic, this suggests SMN repleting therapies must target extra-neuronal tissues and motor neurons for optimal patient outcome. Here we showed that fatty liver is present in SMA and that SMA patient-specific iHeps were susceptible to steatosis. Using proteomics, functional studies and CRISPR/Cas9 gene editing, we confirmed that fatty liver in SMA is a primary SMN-dependent hepatocyte-intrinsic liver defect associated with mitochondrial and other hepatic metabolism implications. These pathologies require monitoring and indicate need for systematic clinical surveillance and additional and/or combinatorial therapies to ensure continued SMA patient health.
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Affiliation(s)
- Damien Meng-Kiat Leow
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yang Kai Ng
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Loo Chien Wang
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Hiromi W.L. Koh
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Tianyun Zhao
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Zi Jian Khong
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Tommaso Tabaglio
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | | | - Richard M. Giadone
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge Massachusetts, USA
| | - Radoslaw M. Sobota
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Shi-Yan Ng
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
- National Neuroscience Institute, Singapore, Singapore
| | - Adrian Kee Keong Teo
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
| | - Simon H. Parson
- Institute of Education in Healthcare and Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, Scotland
| | - Lee L. Rubin
- Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge Massachusetts, USA
| | - Wei-Yi Ong
- Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Basil T. Darras
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Crystal J.J. Yeo
- Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (A*STAR), 61 Biopolis Drive, Proteos, Singapore, Singapore
- Duke-NUS Medical School, Singapore, Singapore
- National Neuroscience Institute, Singapore, Singapore
- Institute of Education in Healthcare and Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen, Scotland
- Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
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Hann SH, Kim SY, Kim YL, Jo YW, Kang JS, Park H, Choi SY, Kong YY. Depletion of SMN protein in mesenchymal progenitors impairs the development of bone and neuromuscular junction in spinal muscular atrophy. eLife 2024; 12:RP92731. [PMID: 38318851 PMCID: PMC10945524 DOI: 10.7554/elife.92731] [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: 02/07/2024] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by the deficiency of the survival motor neuron (SMN) protein, which leads to motor neuron dysfunction and muscle atrophy. In addition to the requirement for SMN in motor neurons, recent studies suggest that SMN deficiency in peripheral tissues plays a key role in the pathogenesis of SMA. Using limb mesenchymal progenitor cell (MPC)-specific SMN-depleted mouse models, we reveal that SMN reduction in limb MPCs causes defects in the development of bone and neuromuscular junction (NMJ). Specifically, these mice exhibited impaired growth plate homeostasis and reduced insulin-like growth factor (IGF) signaling from chondrocytes, rather than from the liver. Furthermore, the reduction of SMN in fibro-adipogenic progenitors (FAPs) resulted in abnormal NMJ maturation, altered release of neurotransmitters, and NMJ morphological defects. Transplantation of healthy FAPs rescued the morphological deterioration. Our findings highlight the significance of mesenchymal SMN in neuromusculoskeletal pathogenesis of SMA and provide insights into potential therapeutic strategies targeting mesenchymal cells for the treatment of SMA.
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Affiliation(s)
- Sang-Hyeon Hann
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Seon-Yong Kim
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea
| | - Ye Lynne Kim
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Young-Woo Jo
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Jong-Seol Kang
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Hyerim Park
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
| | - Se-Young Choi
- Department of Physiology, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea
| | - Young-Yun Kong
- School of Biological Sciences, Seoul National University, Seoul, Republic of Korea
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4
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Miller N, Xu Z, Quinlan KA, Ji A, McGivern JV, Feng Z, Shi H, Ko CP, Tsai LH, Heckman CJ, Ebert AD, Ma YC. Mitigating aberrant Cdk5 activation alleviates mitochondrial defects and motor neuron disease symptoms in spinal muscular atrophy. Proc Natl Acad Sci U S A 2023; 120:e2300308120. [PMID: 37976261 PMCID: PMC10666147 DOI: 10.1073/pnas.2300308120] [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: 01/06/2023] [Accepted: 07/31/2023] [Indexed: 11/19/2023] Open
Abstract
Spinal muscular atrophy (SMA), the top genetic cause of infant mortality, is characterized by motor neuron degeneration. Mechanisms underlying SMA pathogenesis remain largely unknown. Here, we report that the activity of cyclin-dependent kinase 5 (Cdk5) and the conversion of its activating subunit p35 to the more potent activator p25 are significantly up-regulated in mouse models and human induced pluripotent stem cell (iPSC) models of SMA. The increase of Cdk5 activity occurs before the onset of SMA phenotypes, suggesting that it may be an initiator of the disease. Importantly, aberrant Cdk5 activation causes mitochondrial defects and motor neuron degeneration, as the genetic knockout of p35 in an SMA mouse model rescues mitochondrial transport and fragmentation defects, and alleviates SMA phenotypes including motor neuron hyperexcitability, loss of excitatory synapses, neuromuscular junction denervation, and motor neuron degeneration. Inhibition of the Cdk5 signaling pathway reduces the degeneration of motor neurons derived from SMA mice and human SMA iPSCs. Altogether, our studies reveal a critical role for the aberrant activation of Cdk5 in SMA pathogenesis and suggest a potential target for therapeutic intervention.
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Affiliation(s)
- Nimrod Miller
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL60611
| | - Zhaofa Xu
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL60611
| | - Katharina A. Quinlan
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI02881
| | - Amy Ji
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Jered V. McGivern
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI53226
| | - Zhihua Feng
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA90089
| | - Han Shi
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL60611
| | - Chien-Ping Ko
- Section of Neurobiology, Department of Biological Sciences, University of Southern California, Los Angeles, CA90089
| | - Li-Huei Tsai
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, Massachusetts Institute of Technology, Cambridge, MA02139
| | - Charles J. Heckman
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Physical Medicine and Rehabilitation, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL60611
| | - Allison D. Ebert
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI53226
| | - Yongchao C. Ma
- Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, IL60611
- Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children’s Hospital of Chicago, Chicago, IL60611
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL60611
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Kordala AJ, Stoodley J, Ahlskog N, Hanifi M, Garcia Guerra A, Bhomra A, Lim WF, Murray LM, Talbot K, Hammond SM, Wood MJA, Rinaldi C. PRMT inhibitor promotes SMN2 exon 7 inclusion and synergizes with nusinersen to rescue SMA mice. EMBO Mol Med 2023; 15:e17683. [PMID: 37724723 PMCID: PMC10630883 DOI: 10.15252/emmm.202317683] [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: 03/07/2023] [Revised: 08/31/2023] [Accepted: 09/01/2023] [Indexed: 09/21/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant mortality. The advent of approved treatments for this devastating condition has significantly changed SMA patients' life expectancy and quality of life. Nevertheless, these are not without limitations, and research efforts are underway to develop new approaches for improved and long-lasting benefits for patients. Protein arginine methyltransferases (PRMTs) are emerging as druggable epigenetic targets, with several small-molecule PRMT inhibitors already in clinical trials. From a screen of epigenetic molecules, we have identified MS023, a potent and selective type I PRMT inhibitor able to promote SMN2 exon 7 inclusion in preclinical SMA models. Treatment of SMA mice with MS023 results in amelioration of the disease phenotype, with strong synergistic amplification of the positive effect when delivered in combination with the antisense oligonucleotide nusinersen. Moreover, transcriptomic analysis revealed that MS023 treatment has minimal off-target effects, and the added benefit is mainly due to targeting neuroinflammation. Our study warrants further clinical investigation of PRMT inhibition both as a stand-alone and add-on therapy for SMA.
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Affiliation(s)
- Anna J Kordala
- Department of Physiology Anatomy and GeneticsUniversity of OxfordOxfordUK
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Jessica Stoodley
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Nina Ahlskog
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | | | - Antonio Garcia Guerra
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Amarjit Bhomra
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Wooi Fang Lim
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Lyndsay M Murray
- Centre for Discovery Brain Sciences, College of Medicine and Veterinary MedicineUniversity of EdinburghEdinburghUK
- Euan McDonald Centre for Motor Neuron Disease ResearchUniversity of EdinburghEdinburghUK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, John Radcliffe HospitalUniversity of OxfordOxfordUK
- Kavli Institute for Nanoscience DiscoveryUniversity of OxfordOxfordUK
| | | | - Matthew JA Wood
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
- MDUK Oxford Neuromuscular CentreOxfordUK
| | - Carlo Rinaldi
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
- MDUK Oxford Neuromuscular CentreOxfordUK
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Yang XC, Desotell A, Lin MH, Paige AS, Malinowska A, Sun Y, Aik WS, Dadlez M, Tong L, Dominski Z. In vitro methylation of the U7 snRNP subunits Lsm11 and SmE by the PRMT5/MEP50/pICln methylosome. RNA (NEW YORK, N.Y.) 2023; 29:1673-1690. [PMID: 37562960 PMCID: PMC10578488 DOI: 10.1261/rna.079709.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Accepted: 07/08/2023] [Indexed: 08/12/2023]
Abstract
U7 snRNP is a multisubunit endonuclease required for 3' end processing of metazoan replication-dependent histone pre-mRNAs. In contrast to the spliceosomal snRNPs, U7 snRNP lacks the Sm subunits D1 and D2 and instead contains two related proteins, Lsm10 and Lsm11. The remaining five subunits of the U7 heptameric Sm ring, SmE, F, G, B, and D3, are shared with the spliceosomal snRNPs. The pathway that assembles the unique ring of U7 snRNP is unknown. Here, we show that a heterodimer of Lsm10 and Lsm11 tightly interacts with the methylosome, a complex of the arginine methyltransferase PRMT5, MEP50, and pICln known to methylate arginines in the carboxy-terminal regions of the Sm proteins B, D1, and D3 during the spliceosomal Sm ring assembly. Both biochemical and cryo-EM structural studies demonstrate that the interaction is mediated by PRMT5, which binds and methylates two arginine residues in the amino-terminal region of Lsm11. Surprisingly, PRMT5 also methylates an amino-terminal arginine in SmE, a subunit that does not undergo this type of modification during the biogenesis of the spliceosomal snRNPs. An intriguing possibility is that the unique methylation pattern of Lsm11 and SmE plays a vital role in the assembly of the U7 snRNP.
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Affiliation(s)
- Xiao-Cui Yang
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Anthony Desotell
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Min-Han Lin
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Andrew S Paige
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Agata Malinowska
- Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Yadong Sun
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Wei Shen Aik
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Michał Dadlez
- Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Warsaw University, 02-106 Warsaw, Poland
| | - Liang Tong
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Zbigniew Dominski
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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7
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Garcia-Vaquero ML, Heim M, Flix B, Pereira M, Palin L, Marques TM, Pinto FR, de Las Rivas J, Voigt A, Besse F, Gama-Carvalho M. Analysis of asymptomatic Drosophila models for ALS and SMA reveals convergent impact on functional protein complexes linked to neuro-muscular degeneration. BMC Genomics 2023; 24:576. [PMID: 37759179 PMCID: PMC10523761 DOI: 10.1186/s12864-023-09562-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2023] [Accepted: 08/08/2023] [Indexed: 09/29/2023] Open
Abstract
BACKGROUND Spinal Muscular Atrophy (SMA) and Amyotrophic Lateral Sclerosis (ALS) share phenotypic and molecular commonalities, including the fact that they can be caused by mutations in ubiquitous proteins involved in RNA metabolism, namely SMN, TDP-43 and FUS. Although this suggests the existence of common disease mechanisms, there is currently no model to explain the resulting motor neuron dysfunction. In this work we generated a parallel set of Drosophila models for adult-onset RNAi and tagged neuronal expression of the fly orthologues of the three human proteins, named Smn, TBPH and Caz, respectively. We profiled nuclear and cytoplasmic bound mRNAs using a RIP-seq approach and characterized the transcriptome of the RNAi models by RNA-seq. To unravel the mechanisms underlying the common functional impact of these proteins on neuronal cells, we devised a computational approach based on the construction of a tissue-specific library of protein functional modules, selected by an overall impact score measuring the estimated extent of perturbation caused by each gene knockdown. RESULTS Transcriptome analysis revealed that the three proteins do not bind to the same RNA molecules and that only a limited set of functionally unrelated transcripts is commonly affected by their knock-down. However, through our integrative approach we were able to identify a concerted effect on protein functional modules, albeit acting through distinct targets. Most strikingly, functional annotation revealed that these modules are involved in critical cellular pathways for motor neurons, including neuromuscular junction function. Furthermore, selected modules were found to be significantly enriched in orthologues of human neuronal disease genes. CONCLUSIONS The results presented here show that SMA and ALS disease-associated genes linked to RNA metabolism functionally converge on neuronal protein complexes, providing a new hypothesis to explain the common motor neuron phenotype. The functional modules identified represent promising biomarkers and therapeutic targets, namely given their alteration in asymptomatic settings.
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Affiliation(s)
- Marina L Garcia-Vaquero
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
- Department of Medicine and Cytometry General Service-15 Nucleus, Cancer Research Centre (IBMCC/CSIC/USAL/IBSAL), CIBERONC, 16 37007, Salamanca, Spain
| | - Marjorie Heim
- Institut de Biologie Valrose, Université Côte d'Azur, CNRS, 06108, Nice, Inserm, France
| | - Barbara Flix
- Department of Neurology, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
| | - Marcelo Pereira
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Lucile Palin
- Institut de Biologie Valrose, Université Côte d'Azur, CNRS, 06108, Nice, Inserm, France
| | - Tânia M Marques
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Francisco R Pinto
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal
| | - Javier de Las Rivas
- Cancer Research Center (CiC-IBMCC, CSIC/USAL/IBSAL), Consejo Superior de Investigaciones Científicas (CSIC) and University of Salamanca (USAL), 37007, Salamanca, Spain
| | - Aaron Voigt
- Department of Neurology, Medical Faculty, RWTH Aachen University, 52074, Aachen, Germany
- JARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, Forschungszentrum Jülich GmbH RWTH Aachen University, 52074, Aachen, Germany
| | - Florence Besse
- Institut de Biologie Valrose, Université Côte d'Azur, CNRS, 06108, Nice, Inserm, France
| | - Margarida Gama-Carvalho
- BioISI - Institute for Biosystems and Integrative Sciences, Faculty of Sciences, University of Lisbon, 1749-016, Lisbon, Portugal.
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8
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Cottam NC, Bamfo T, Harrington MA, Charvet CJ, Hekmatyar K, Tulin N, Sun J. Cerebellar structural, astrocytic, and neuronal abnormalities in the SMNΔ7 mouse model of spinal muscular atrophy. Brain Pathol 2023; 33:e13162. [PMID: 37218083 PMCID: PMC10467044 DOI: 10.1111/bpa.13162] [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: 11/18/2022] [Accepted: 04/18/2023] [Indexed: 05/24/2023] Open
Abstract
Spinalmuscular atrophy (SMA) is a neuromuscular disease that affects as many as 1 in 6000 individuals at birth, making it the leading genetic cause of infant mortality. A growing number of studies indicate that SMA is a multi-system disease. The cerebellum has received little attention even though it plays an important role in motor function and widespread pathology has been reported in the cerebella of SMA patients. In this study, we assessed SMA pathology in the cerebellum using structural and diffusion magnetic resonance imaging, immunohistochemistry, and electrophysiology with the SMNΔ7 mouse model. We found a significant disproportionate loss in cerebellar volume, decrease in afferent cerebellar tracts, selective lobule-specific degeneration of Purkinje cells, abnormal lobule foliation and astrocyte integrity, and a decrease in spontaneous firing of cerebellar output neurons in the SMA mice compared to controls. Our data suggest that defects in cerebellar structure and function due to decreased survival motor neuron (SMN) levels impair the functional cerebellar output affecting motor control, and that cerebellar pathology should be addressed to achieve comprehensive treatment and therapy for SMA patients.
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Affiliation(s)
- Nicholas C. Cottam
- Department of Biological SciencesDelaware State UniversityDoverDelawareUSA
| | - Tiffany Bamfo
- Department of Biological SciencesDelaware State UniversityDoverDelawareUSA
| | | | - Christine J. Charvet
- Delaware Center for Neuroscience ResearchDelaware State UniversityDoverDelawareUSA
- Department of Anatomy, Physiology and PharmacologyAuburn UniversityAuburnAlabamaUSA
- Department of PsychologyDelaware State UniversityDoverDEUnited States
| | - Khan Hekmatyar
- Center for Biomedical and Brain ImagingUniversity of DelawareNewarkDelawareUSA
- Bioimaging Research Center for Biomedical and Brain ImagingUniversity of GeorgiaAthensGeorgiaUSA
| | - Nikita Tulin
- Department of NeuroscienceTemple UniversityPhiladelphiaPennsylvaniaUSA
| | - Jianli Sun
- Department of Biological SciencesDelaware State UniversityDoverDelawareUSA
- Delaware Center for Neuroscience ResearchDelaware State UniversityDoverDelawareUSA
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9
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Morales ML, García-Vicente R, Rodríguez-García A, Reyes-Palomares A, Vincelle-Nieto Á, Álvarez N, Ortiz-Ruiz A, Garrido-García V, Giménez A, Carreño-Tarragona G, Sánchez R, Ayala R, Martínez-López J, Linares M. Posttranslational splicing modifications as a key mechanism in cytarabine resistance in acute myeloid leukemia. Leukemia 2023; 37:1649-1659. [PMID: 37422594 PMCID: PMC10400425 DOI: 10.1038/s41375-023-01963-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 06/14/2023] [Accepted: 06/29/2023] [Indexed: 07/10/2023]
Abstract
Despite the approval of several drugs for AML, cytarabine is still widely used as a therapeutic approach. However, 85% of patients show resistance and only 10% overcome the disease. Using RNA-seq and phosphoproteomics, we show that RNA splicing and serine-arginine-rich (SR) proteins phosphorylation were altered during cytarabine resistance. Moreover, phosphorylation of SR proteins at diagnosis were significantly lower in responder than non-responder patients, pointing to their utility to predict response. These changes correlated with altered transcriptomic profiles of SR protein target genes. Notably, splicing inhibitors were therapeutically effective in treating sensitive and resistant AML cells as monotherapy or combination with other approved drugs. H3B-8800 and venetoclax combination showed the best efficacy in vitro, demonstrating synergistic effects in patient samples and no toxicity in healthy hematopoietic progenitors. Our results establish that RNA splicing inhibition, alone or combined with venetoclax, could be useful for the treatment of newly diagnosed or relapsed/refractory AML.
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Affiliation(s)
- María Luz Morales
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain.
| | - Roberto García-Vicente
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
| | - Alba Rodríguez-García
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
| | - Armando Reyes-Palomares
- Department of Biochemistry and Molecular Biology, Veterinary School, Universidad Complutense de Madrid, ES 28040, Madrid, Spain
| | - África Vincelle-Nieto
- Department of Biochemistry and Molecular Biology, Veterinary School, Universidad Complutense de Madrid, ES 28040, Madrid, Spain
| | - Noemí Álvarez
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
| | - Alejandra Ortiz-Ruiz
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
| | - Vanesa Garrido-García
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
| | - Alicia Giménez
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
| | - Gonzalo Carreño-Tarragona
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
| | - Ricardo Sánchez
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
| | - Rosa Ayala
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
- Department of Medicine, Medicine School, Universidad Complutense de Madrid, ES 28040, Madrid, Spain
| | - Joaquín Martínez-López
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain
- Department of Medicine, Medicine School, Universidad Complutense de Madrid, ES 28040, Madrid, Spain
| | - María Linares
- Department of Translational Hematology, Instituto de Investigación Sanitaria Hospital 12 de Octubre (imas12), Hematological Malignancies Clinical Research Unit H12O-CNIO, Hospital 12 de Octubre - Centro Nacional de Investigaciones Oncológicas, CIBERONC, ES 28041, Madrid, Spain.
- Department of Biochemistry and Molecular Biology, Pharmacy School, Universidad Complutense de Madrid, ES 28040, Madrid, Spain.
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10
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Lumpkin CJ, Harris AW, Connell AJ, Kirk RW, Whiting JA, Saieva L, Pellizzoni L, Burghes AHM, Butchbach MER. Evaluation of the orally bioavailable 4-phenylbutyrate-tethered trichostatin A analogue AR42 in models of spinal muscular atrophy. Sci Rep 2023; 13:10374. [PMID: 37365234 PMCID: PMC10293174 DOI: 10.1038/s41598-023-37496-0] [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: 09/07/2022] [Accepted: 06/22/2023] [Indexed: 06/28/2023] Open
Abstract
Proximal spinal muscular atrophy (SMA) is a leading genetic cause for infant death in the world and results from the selective loss of motor neurons in the spinal cord. SMA is a consequence of low levels of SMN protein and small molecules that can increase SMN expression are of considerable interest as potential therapeutics. Previous studies have shown that both 4-phenylbutyrate (4PBA) and trichostatin A (TSA) increase SMN expression in dermal fibroblasts derived from SMA patients. AR42 is a 4PBA-tethered TSA derivative that is a very potent histone deacetylase inhibitor. SMA patient fibroblasts were treated with either AR42, AR19 (a related analogue), 4PBA, TSA or vehicle for 5 days and then immunostained for SMN localization. AR42 as well as 4PBA and TSA increased the number of SMN-positive nuclear gems in a dose-dependent manner while AR19 did not show marked changes in gem numbers. While gem number was increased in AR42-treated SMA fibroblasts, there were no significant changes in FL-SMN mRNA or SMN protein. The neuroprotective effect of this compound was then assessed in SMNΔ7 SMA (SMN2+/+;SMNΔ7+/+;mSmn-/-) mice. Oral administration of AR42 prior to disease onset increased the average lifespan of SMNΔ7 SMA mice by ~ 27% (20.1 ± 1.6 days for AR42-treated mice vs. 15.8 ± 0.4 days for vehicle-treated mice). AR42 treatment also improved motor function in these mice. AR42 treatment inhibited histone deacetylase (HDAC) activity in treated spinal cord although it did not affect SMN protein expression in these mice. AKT and GSK3β phosphorylation were both significantly increased in SMNΔ7 SMA mouse spinal cords. In conclusion, presymptomatic administration of the HDAC inhibitor AR42 ameliorates the disease phenotype in SMNΔ7 SMA mice in a SMN-independent manner possibly by increasing AKT neuroprotective signaling.
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Affiliation(s)
- Casey J Lumpkin
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Ashlee W Harris
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Andrew J Connell
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Ryan W Kirk
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Joshua A Whiting
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Luciano Saieva
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Livio Pellizzoni
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
- Department of Neurology, Columbia University, New York, NY, USA
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
| | - Arthur H M Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Matthew E R Butchbach
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA.
- Department of Biological Sciences, University of Delaware, Newark, DE, USA.
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA, USA.
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11
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Nakevska Z, Yokota T. Challenges and future perspective of antisense therapy for spinal muscular atrophy: A review. Eur J Cell Biol 2023; 102:151326. [PMID: 37295266 DOI: 10.1016/j.ejcb.2023.151326] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 05/18/2023] [Accepted: 05/20/2023] [Indexed: 06/12/2023] Open
Abstract
Spinal muscular atrophy (SMA), the most common genetic cause of infantile death, is caused by a mutation in the survival of motor neuron 1 gene (SMN1), leading to the death of motor neurons and progressive muscle weakness. SMN1 normally produces an essential protein called SMN. Although humans possess a paralogous gene called SMN2, ∼90% of the SMN it produces is non-functional. This is due to a mutation in SMN2 that causes the skipping of a required exon during splicing of the pre-mRNA. The first treatment for SMA, nusinersen (brand name Spinraza), was approved by the FDA in 2016 and by the EMU in 2017. Nusinersen is an antisense oligonucleotide-based therapy that alters the splicing of SMN2 to make functional full-length SMN protein. Despite the recent advancements in antisense oligonucleotide therapy and SMA treatment development, nusinersen is faced with a multitude of challenges, such as intracellular and systemic delivery. In recent years, the use of peptide-conjugated phosphorodiamidate morpholino oligomers (PPMOs) in antisense therapy has gained interest. These are antisense oligonucleotides conjugated to cell-penetrating peptides such as Pips and DG9, and they have the potential to address the challenges associated with delivery. This review focuses on the historic milestones, development, current challenges, and future perspectives of antisense therapy for SMA.
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Affiliation(s)
- Zorica Nakevska
- Department of Biological Sciences, Faculty of Science, University of Alberta, 116 St. and 85 Ave., Edmonton AB T6G 2E1, Canada.
| | - Toshifumi Yokota
- Neuroscience and Mental Health Institute, Faculty of Medicine and Dentistry, University of Alberta, 116 St. and 85 Ave., Edmonton AB T6G 2E1, Canada; Department of Medical Genetics, Faculty of Medicine and Dentistry, University of Alberta, 116 St. and 85 Ave., Edmonton AB T6G 2E1, Canada; The Friends of Garret Cumming Research and Muscular Dystrophy Canada HM Toupin Neurological Science Research Chair, 8812 112 St., Edmonton AB T6G 2H7, Canada.
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12
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Yang XC, Desotell A, Lin MH, Paige AS, Malinowska A, Sun Y, Aik WS, Dadlez M, Tong L, Dominski Z. In vitro methylation of the U7 snRNP subunits Lsm11 and SmE by the PRMT5/MEP50/pICln methylosome. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.10.540203. [PMID: 37215023 PMCID: PMC10197641 DOI: 10.1101/2023.05.10.540203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
U7 snRNP is a multi-subunit endonuclease required for 3' end processing of metazoan replication-dependent histone pre-mRNAs. In contrast to the spliceosomal snRNPs, U7 snRNP lacks the Sm subunits D1 and D2 and instead contains two related proteins, Lsm10 and Lsm11. The remaining five subunits of the U7 heptameric Sm ring, SmE, F, G, B and D3, are shared with the spliceosomal snRNPs. The pathway that assembles the unique ring of U7 snRNP is unknown. Here, we show that a heterodimer of Lsm10 and Lsm11 tightly interacts with the methylosome, a complex of the arginine methyltransferase PRMT5, MEP50 and pICln known to methylate arginines in the C-terminal regions of the Sm proteins B, D1 and D3 during the spliceosomal Sm ring assembly. Both biochemical and Cryo-EM structural studies demonstrate that the interaction is mediated by PRMT5, which binds and methylates two arginine residues in the N-terminal region of Lsm11. Surprisingly, PRMT5 also methylates an N-terminal arginine in SmE, a subunit that does not undergo this type of modification during the biogenesis of the spliceosomal snRNPs. An intriguing possibility is that the unique methylation pattern of Lsm11 and SmE plays a vital role in the assembly of the U7 snRNP.
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13
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Nadal M, Anton R, Dorca‐Arévalo J, Estébanez‐Perpiñá E, Tizzano EF, Fuentes‐Prior P. Structure and function analysis of Sam68 and hnRNP A1 synergy in the exclusion of exon 7 from SMN2 transcripts. Protein Sci 2023; 32:e4553. [PMID: 36560896 PMCID: PMC10031812 DOI: 10.1002/pro.4553] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 12/13/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by the absence of a functional copy of the Survival of Motor Neuron 1 gene (SMN1). The nearly identical paralog, SMN2, cannot compensate for the loss of SMN1 because exon 7 is aberrantly skipped from most SMN2 transcripts, a process mediated by synergistic activities of Src-associated during mitosis, 68 kDa (Sam68/KHDRBS1) and heterogeneous nuclear ribonucleoprotein (hnRNP) A1. This results in the production of a truncated, nonfunctional protein that is rapidly degraded. Here, we present several crystal structures of Sam68 RNA-binding domain (RBD). Sam68-RBD forms stable symmetric homodimers by antiparallel association of helices α3 from two monomers. However, the details of domain organization and the dimerization interface differ significantly from previously characterized homologs. We demonstrate that Sam68 and hnRNP A1 can simultaneously bind proximal motifs within the central region of SMN2 (ex7). Furthermore, we show that the RNA-binding pockets of the two proteins are close to each other in their heterodimeric complex and identify contact residues using crosslinking-mass spectrometry. We present a model of the ternary Sam68·SMN2 (ex7)·hnRNP A1 complex that reconciles all available information on SMN1/2 splicing. Our findings have important implications for the etiology of SMA and open new avenues for the design of novel therapeutics to treat splicing diseases.
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Affiliation(s)
- Marta Nadal
- Molecular Bases of DiseaseBiomedical Research Institute Sant Pau (IIB Sant Pau)BarcelonaSpain
| | - Rosa Anton
- Molecular Bases of DiseaseBiomedical Research Institute Sant Pau (IIB Sant Pau)BarcelonaSpain
| | - Jonatan Dorca‐Arévalo
- Molecular Bases of DiseaseBiomedical Research Institute Sant Pau (IIB Sant Pau)BarcelonaSpain
- Present address:
Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Campus of BellvitgeHospitalet de Llobregat, University of BarcelonaBarcelonaSpain
| | - Eva Estébanez‐Perpiñá
- Structural Biology of Nuclear Receptors, Department of Biochemistry and Molecular Biomedicine, Faculty of BiologyInstitute of Biomedicine (IBUB) of the University of Barcelona (UB)BarcelonaSpain
| | - Eduardo F. Tizzano
- Medicine Genetics GroupVall d'Hebron Research Institute (VHIR)BarcelonaSpain
- Department of Clinical and Molecular GeneticsHospital Vall d'HebronBarcelonaSpain
| | - Pablo Fuentes‐Prior
- Molecular Bases of DiseaseBiomedical Research Institute Sant Pau (IIB Sant Pau)BarcelonaSpain
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14
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Ikenaka A, Kitagawa Y, Yoshida M, Lin CY, Niwa A, Nakahata T, Saito MK. SMN promotes mitochondrial metabolic maturation during myogenesis by regulating the MYOD-miRNA axis. Life Sci Alliance 2023; 6:e202201457. [PMID: 36604149 PMCID: PMC9834662 DOI: 10.26508/lsa.202201457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 01/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a congenital neuromuscular disease caused by the mutation or deletion of the survival motor neuron 1 (SMN1) gene. Although the primary cause of progressive muscle atrophy in SMA has classically been considered the degeneration of motor neurons, recent studies have indicated a skeletal muscle-specific pathological phenotype such as impaired mitochondrial function and enhanced cell death. Here, we found that the down-regulation of SMN causes mitochondrial dysfunction and subsequent cell death in in vitro models of skeletal myogenesis with both a murine C2C12 cell line and human induced pluripotent stem cells. During myogenesis, SMN binds to the upstream genomic regions of MYOD1 and microRNA (miR)-1 and miR-206. Accordingly, the loss of SMN down-regulates these miRs, whereas supplementation of the miRs recovers the mitochondrial function, cell survival, and myotube formation of SMN-deficient C2C12, indicating the SMN-miR axis is essential for myogenic metabolic maturation. In addition, the introduction of the miRs into ex vivo muscle stem cells derived from Δ7-SMA mice caused myotube formation and muscle contraction. In conclusion, our data revealed novel transcriptional roles of SMN during myogenesis, providing an alternative muscle-oriented therapeutic strategy for SMA patients.
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Affiliation(s)
- Akihiro Ikenaka
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Yohko Kitagawa
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Michiko Yoshida
- Department of Pediatrics, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Chuang-Yu Lin
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
- Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Akira Niwa
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Tatsutoshi Nakahata
- Drug Discovery Technology Development Office, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
| | - Megumu K Saito
- Department of Clinical Application, Center for iPS Cell Research and Application, Kyoto University, Kyoto, Japan
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15
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Muiños-Bühl A, Rombo R, Ling KK, Zilio E, Rigo F, Bennett CF, Wirth B. Long-Term SMN- and Ncald-ASO Combinatorial Therapy in SMA Mice and NCALD-ASO Treatment in hiPSC-Derived Motor Neurons Show Protective Effects. Int J Mol Sci 2023; 24:ijms24044198. [PMID: 36835624 PMCID: PMC9961752 DOI: 10.3390/ijms24044198] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/17/2023] [Accepted: 02/19/2023] [Indexed: 02/22/2023] Open
Abstract
For SMA patients with only two SMN2 copies, available therapies might be insufficient to counteract lifelong motor neuron (MN) dysfunction. Therefore, additional SMN-independent compounds, supporting SMN-dependent therapies, might be beneficial. Neurocalcin delta (NCALD) reduction, an SMA protective genetic modifier, ameliorates SMA across species. In a low-dose SMN-ASO-treated severe SMA mouse model, presymptomatic intracerebroventricular (i.c.v.) injection of Ncald-ASO at postnatal day 2 (PND2) significantly ameliorates histological and electrophysiological SMA hallmarks at PND21. However, contrary to SMN-ASOs, Ncald-ASOs show a shorter duration of action limiting a long-term benefit. Here, we investigated the longer-term effect of Ncald-ASOs by additional i.c.v. bolus injection at PND28. Two weeks after injection of 500 µg Ncald-ASO in wild-type mice, NCALD was significantly reduced in the brain and spinal cord and well tolerated. Next, we performed a double-blinded preclinical study combining low-dose SMN-ASO (PND1) with 2× i.c.v. Ncald-ASO or CTRL-ASO (100 µg at PND2, 500 µg at PND28). Ncald-ASO re-injection significantly ameliorated electrophysiological defects and NMJ denervation at 2 months. Moreover, we developed and identified a non-toxic and highly efficient human NCALD-ASO that significantly reduced NCALD in hiPSC-derived MNs. This improved both neuronal activity and growth cone maturation of SMA MNs, emphasizing the additional protective effect of NCALD-ASO treatment.
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Affiliation(s)
- Anixa Muiños-Bühl
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | - Roman Rombo
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | | | - Eleonora Zilio
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
| | - Frank Rigo
- IONIS Pharmaceuticals, Carlsbad, CA 92010, USA
| | | | - Brunhilde Wirth
- Institute of Human Genetics, University of Cologne, 50931 Cologne, Germany
- Center for Molecular Medicine Cologne, University of Cologne, 50931 Cologne, Germany
- Center for Rare Diseases Cologne, University Hospital of Cologne, 50931 Cologne, Germany
- Correspondence:
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16
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Riboldi GM, Faravelli I, Rinchetti P, Lotti F. SMN post-translational modifications in spinal muscular atrophy. Front Cell Neurosci 2023; 17:1092488. [PMID: 36874214 PMCID: PMC9981653 DOI: 10.3389/fncel.2023.1092488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/26/2023] [Indexed: 02/19/2023] Open
Abstract
Since its first identification as the gene responsible for spinal muscular atrophy (SMA), the range of survival motor neuron (SMN) protein functions has increasingly expanded. This multimeric complex plays a crucial role in a variety of RNA processing pathways. While its most characterized function is in the biogenesis of ribonucleoproteins, several studies have highlighted the SMN complex as an important contributor to mRNA trafficking and translation, axonal transport, endocytosis, and mitochondria metabolism. All these multiple functions need to be selectively and finely modulated to maintain cellular homeostasis. SMN has distinct functional domains that play a crucial role in complex stability, function, and subcellular distribution. Many different processes were reported as modulators of the SMN complex activities, although their contribution to SMN biology still needs to be elucidated. Recent evidence has identified post-translational modifications (PTMs) as a way to regulate the pleiotropic functions of the SMN complex. These modifications include phosphorylation, methylation, ubiquitination, acetylation, sumoylation, and many other types. PTMs can broaden the range of protein functions by binding chemical moieties to specific amino acids, thus modulating several cellular processes. Here, we provide an overview of the main PTMs involved in the regulation of the SMN complex with a major focus on the functions that have been linked to SMA pathogenesis.
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Affiliation(s)
| | | | | | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY, United States
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17
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Faravelli I, Riboldi GM, Rinchetti P, Lotti F. The SMN Complex at the Crossroad between RNA Metabolism and Neurodegeneration. Int J Mol Sci 2023; 24:2247. [PMID: 36768569 PMCID: PMC9917330 DOI: 10.3390/ijms24032247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
In the cell, RNA exists and functions in a complex with RNA binding proteins (RBPs) that regulate each step of the RNA life cycle from transcription to degradation. Central to this regulation is the role of several molecular chaperones that ensure the correct interactions between RNA and proteins, while aiding the biogenesis of large RNA-protein complexes (ribonucleoproteins or RNPs). Accurate formation of RNPs is fundamentally important to cellular development and function, and its impairment often leads to disease. The survival motor neuron (SMN) protein exemplifies this biological paradigm. SMN is part of a multi-protein complex essential for the biogenesis of various RNPs that function in RNA metabolism. Mutations leading to SMN deficiency cause the neurodegenerative disease spinal muscular atrophy (SMA). A fundamental question in SMA biology is how selective motor system dysfunction results from reduced levels of the ubiquitously expressed SMN protein. Recent clarification of the central role of the SMN complex in RNA metabolism and a thorough characterization of animal models of SMA have significantly advanced our knowledge of the molecular basis of the disease. Here we review the expanding role of SMN in the regulation of gene expression through its multiple functions in RNP biogenesis. We discuss developments in our understanding of SMN activity as a molecular chaperone of RNPs and how disruption of SMN-dependent RNA pathways can contribute to the SMA phenotype.
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Affiliation(s)
- Irene Faravelli
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Giulietta M. Riboldi
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
- The Marlene and Paolo Fresco Institute for Parkinson’s and Movement Disorders, NYU Langone Health, New York, NY 10017, USA
| | - Paola Rinchetti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
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18
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Ding Z, Meng YR, Fan YJ, Xu YZ. Roles of minor spliceosome in intron recognition and the convergence with the better understood major spliceosome. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1761. [PMID: 36056453 DOI: 10.1002/wrna.1761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 06/06/2022] [Accepted: 08/06/2022] [Indexed: 01/31/2023]
Abstract
Catalyzed by spliceosomes in the nucleus, RNA splicing removes intronic sequences from precursor RNAs in eukaryotes to generate mature RNA, which also significantly increases proteome complexity and fine-tunes gene expression. Most metazoans have two coexisting spliceosomes; the major spliceosome, which removes >99.5% of introns, and the minor spliceosome, which removes far fewer introns (only 770 at present have been predicted in the human genome). Both spliceosomes are large and dynamic machineries, each consisting of five small nuclear RNAs (snRNAs) and more than 100 proteins. However, the dynamic assembly, catalysis, and protein composition of the minor spliceosome are still poorly understood. With different splicing signals, minor introns are rare and usually distributed alone and flanked by major introns in genes, raising questions of how they are recognized by the minor spliceosome and how their processing deals with the splicing of neighboring major introns. Due to large numbers of introns and close similarities between the two machinery, cooperative, and competitive recognition by the two spliceosomes has been investigated. Functionally, many minor-intron-containing genes are evolutionarily conserved and essential. Mutations in the minor spliceosome exhibit a variety of developmental defects in plants and animals and are linked to numerous human diseases. Here, we review recent progress in the understanding of minor splicing, compare currently known components of the two spliceosomes, survey minor introns in a wide range of organisms, discuss cooperation and competition of the two spliceosomes in splicing of minor-intron-containing genes, and contributions of minor splicing mutations in development and diseases. This article is categorized under: RNA Processing > Processing of Small RNAs RNA Processing > Splicing Mechanisms RNA Structure and Dynamics > RNA Structure, Dynamics and Chemistry.
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Affiliation(s)
- Zhan Ding
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China.,Key Laboratory of Insect Developmental and Evolutionary Biology, Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yan-Ran Meng
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
| | - Yu-Jie Fan
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
| | - Yong-Zhen Xu
- RNA Institute, State Key Laboratory of Virology, and Hubei Key Laboratory of Cell Homeostasis, College of Life Science, Wuhan University, Wuhan, Hubei, China
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19
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Miralles MP, Sansa A, Beltran M, Soler RM, Garcera A. Survival motor neuron protein and neurite degeneration are regulated by Gemin3 in spinal muscular atrophy motoneurons. Front Cell Neurosci 2022; 16:1054270. [PMID: 36619669 PMCID: PMC9813745 DOI: 10.3389/fncel.2022.1054270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 12/06/2022] [Indexed: 12/24/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a genetic neuromuscular disorder caused by reduction of the ubiquitously expressed protein Survival Motor Neuron (SMN). Low levels of SMN impact on spinal cord motoneurons (MNs) causing their degeneration and progressive muscle weakness and atrophy. To study the molecular mechanisms leading to cell loss in SMN-reduced MNs, we analyzed the NF-κB intracellular pathway in SMA models. NF-κB pathway activation is required for survival and regulates SMN levels in cultured MNs. Here we describe that NF-κB members, inhibitor of kappa B kinase beta (IKKβ), and RelA, were reduced in SMA mouse and human MNs. In addition, we observed that Gemin3 protein level was decreased in SMA MNs, but not in non-neuronal SMA cells. Gemin3 is a core member of the SMN complex responsible for small nuclear ribonucleoprotein biogenesis, and it regulates NF-κB activation through the mitogen-activated protein kinase TAK1. Our experiments showed that Gemin3 knockdown reduced SMN, IKKβ, and RelA protein levels, and caused significant neurite degeneration. Overexpression of SMN increased Gemin3 protein in SMA MNs, but did not prevent neurite degeneration in Gemin3 knockdown cells. These data indicated that Gemin3 reduction may contribute to cell degeneration in SMA MNs.
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20
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Hammond SM, Abendroth F, Goli L, Stoodley J, Burrell M, Thom G, Gurrell I, Ahlskog N, Gait MJ, Wood MJ, Webster CI. Antibody-oligonucleotide conjugate achieves CNS delivery in animal models for spinal muscular atrophy. JCI Insight 2022; 7:154142. [PMID: 36346674 PMCID: PMC7614086 DOI: 10.1172/jci.insight.154142] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
Antisense oligonucleotides (ASOs) have emerged as one of the most innovative new genetic drug modalities. However, their high molecular weight limits their bioavailability for otherwise-treatable neurological disorders. We investigated conjugation of ASOs to an antibody against the murine transferrin receptor, 8D3130, and evaluated it via systemic administration in mouse models of the neurodegenerative disease spinal muscular atrophy (SMA). SMA, like several other neurological and neuromuscular diseases, is treatable with single-stranded ASOs that modulate splicing of the survival motor neuron 2 (SMN2) gene. Administration of 8D3130-ASO conjugate resulted in elevated levels of bioavailability to the brain. Additionally, 8D3130-ASO yielded therapeutic levels of SMN2 splicing in the central nervous system of adult human SMN2-transgenic (hSMN2-transgenic) mice, which resulted in extended survival of a severely affected SMA mouse model. Systemic delivery of nucleic acid therapies with brain-targeting antibodies offers powerful translational potential for future treatments of neuromuscular and neurodegenerative diseases.
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Affiliation(s)
- Suzan M Hammond
- Department of Paediatrics, John Radcliffe Hospital, and.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, United Kingdom
| | - Frank Abendroth
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom.,Department of Chemistry, Philipps Universität-Marburg, Marburg, Germany
| | - Larissa Goli
- Department of Paediatrics, John Radcliffe Hospital, and.,Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Jessica Stoodley
- Department of Paediatrics, John Radcliffe Hospital, and.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, United Kingdom
| | | | | | - Ian Gurrell
- Neuroscience, Biopharmaceuticals, AstraZeneca, Cambridge, United Kingdom
| | - Nina Ahlskog
- Department of Paediatrics, John Radcliffe Hospital, and.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, United Kingdom
| | - Michael J Gait
- Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Matthew Ja Wood
- Department of Paediatrics, John Radcliffe Hospital, and.,MDUK Oxford Neuromuscular Centre, University of Oxford, Oxford, United Kingdom
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21
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Chen L, Roake CM, Maccallini P, Bavasso F, Dehghannasiri R, Santonicola P, Mendoza-Ferreira N, Scatolini L, Rizzuti L, Esposito A, Gallotta I, Francia S, Cacchione S, Galati A, Palumbo V, Kobin MA, Tartaglia G, Colantoni A, Proietti G, Wu Y, Hammerschmidt M, De Pittà C, Sales G, Salzman J, Pellizzoni L, Wirth B, Di Schiavi E, Gatti M, Artandi S, Raffa GD. TGS1 impacts snRNA 3'-end processing, ameliorates survival motor neuron-dependent neurological phenotypes in vivo and prevents neurodegeneration. Nucleic Acids Res 2022; 50:12400-12424. [PMID: 35947650 PMCID: PMC9757054 DOI: 10.1093/nar/gkac659] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/21/2022] [Indexed: 12/24/2022] Open
Abstract
Trimethylguanosine synthase 1 (TGS1) is a highly conserved enzyme that converts the 5'-monomethylguanosine cap of small nuclear RNAs (snRNAs) to a trimethylguanosine cap. Here, we show that loss of TGS1 in Caenorhabditis elegans, Drosophila melanogaster and Danio rerio results in neurological phenotypes similar to those caused by survival motor neuron (SMN) deficiency. Importantly, expression of human TGS1 ameliorates the SMN-dependent neurological phenotypes in both flies and worms, revealing that TGS1 can partly counteract the effects of SMN deficiency. TGS1 loss in HeLa cells leads to the accumulation of immature U2 and U4atac snRNAs with long 3' tails that are often uridylated. snRNAs with defective 3' terminations also accumulate in Drosophila Tgs1 mutants. Consistent with defective snRNA maturation, TGS1 and SMN mutant cells also exhibit partially overlapping transcriptome alterations that include aberrantly spliced and readthrough transcripts. Together, these results identify a neuroprotective function for TGS1 and reinforce the view that defective snRNA maturation affects neuronal viability and function.
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Affiliation(s)
- Lu Chen
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
- Cancer Signaling and Epigenetics Program and Cancer Epigenetics Institute, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Caitlin M Roake
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Paolo Maccallini
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Francesca Bavasso
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Roozbeh Dehghannasiri
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Biomedical Data Science, Stanford University, Stanford, CA 94305, USA
| | | | - Natalia Mendoza-Ferreira
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, 50931 Cologne, Germany
| | - Livia Scatolini
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Ludovico Rizzuti
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | | | - Ivan Gallotta
- Institute of Genetics and Biophysics, IGB-ABT, CNR, Naples, Italy
| | - Sofia Francia
- IFOM-The FIRC Institute of Molecular Oncology, Milan, Italy
- Istituto di Genetica Molecolare, CNR-Consiglio Nazionale delle Ricerche, Pavia, Italy
| | - Stefano Cacchione
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Alessandra Galati
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Valeria Palumbo
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Marie A Kobin
- Cancer Signaling and Epigenetics Program and Cancer Epigenetics Institute, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Gian Gaetano Tartaglia
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), Rome 00161, Italy
- Center for Human Technology, Fondazione Istituto Italiano di Tecnologia (IIT), Genoa 16152, Italy
| | - Alessio Colantoni
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), Rome 00161, Italy
- Center for Human Technology, Fondazione Istituto Italiano di Tecnologia (IIT), Genoa 16152, Italy
| | - Gabriele Proietti
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), Rome 00161, Italy
- Center for Human Technology, Fondazione Istituto Italiano di Tecnologia (IIT), Genoa 16152, Italy
| | - Yunming Wu
- Cancer Signaling and Epigenetics Program and Cancer Epigenetics Institute, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
- Department of Biology, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Matthias Hammerschmidt
- Institute for Zoology, Developmental Biology, University of Cologne, 50674 Cologne, Germany
| | | | - Gabriele Sales
- Department of Biology, University of Padova, Padua, Italy
| | - Julia Salzman
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Biomedical Data Science, Stanford University, Stanford, CA 94305, USA
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Columbia University, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University, NY 10032, USA
- Department of Neurology, Columbia University, NY 10032, USA
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, 50931 Cologne, Germany
- Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
| | - Elia Di Schiavi
- Institute of Biosciences and BioResources, IBBR, CNR, Naples, Italy
- Institute of Genetics and Biophysics, IGB-ABT, CNR, Naples, Italy
| | - Maurizio Gatti
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
- Istituto di Biologia e Patologia Molecolari (IBPM) del CNR, Rome, Italy
| | - Steven E Artandi
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Grazia D Raffa
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
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22
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A link between agrin signalling and Ca v3.2 at the neuromuscular junction in spinal muscular atrophy. Sci Rep 2022; 12:18960. [PMID: 36347955 PMCID: PMC9643518 DOI: 10.1038/s41598-022-23703-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 11/03/2022] [Indexed: 11/11/2022] Open
Abstract
SMN protein deficiency causes motoneuron disease spinal muscular atrophy (SMA). SMN-based therapies improve patient motor symptoms to variable degrees. An early hallmark of SMA is the perturbation of the neuromuscular junction (NMJ), a synapse between a motoneuron and muscle cell. NMJ formation depends on acetylcholine receptor (AChR) clustering triggered by agrin and its co-receptors lipoprotein receptor-related protein 4 (LRP4) and transmembrane muscle-specific kinase (MuSK) signalling pathway. We have previously shown that flunarizine improves NMJs in SMA model mice, but the mechanisms remain elusive. We show here that flunarizine promotes AChR clustering in cell-autonomous, dose- and agrin-dependent manners in C2C12 myotubes. This is associated with an increase in protein levels of LRP4, integrin-beta-1 and alpha-dystroglycan, three agrin co-receptors. Furthermore, flunarizine enhances MuSK interaction with integrin-beta-1 and phosphotyrosines. Moreover, the drug acts on the expression and splicing of Agrn and Cacna1h genes in a muscle-specific manner. We reveal that the Cacna1h encoded protein Cav3.2 closely associates in vitro with the agrin co-receptor LRP4. In vivo, it is enriched nearby NMJs during neonatal development and the drug increases this immunolabelling in SMA muscles. Thus, flunarizine modulates key players of the NMJ and identifies Cav3.2 as a new protein involved in the NMJ biology.
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23
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Oprişoreanu AM. Perspective on automated in vivo drug screening using the chodl mutant zebrafish line. Neural Regen Res 2022; 17:2437-2438. [PMID: 35535889 PMCID: PMC9120713 DOI: 10.4103/1673-5374.335795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/31/2021] [Accepted: 09/08/2021] [Indexed: 11/04/2022] Open
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24
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The Role of Small Heat Shock Proteins in Protein Misfolding Associated Motoneuron Diseases. Int J Mol Sci 2022; 23:ijms231911759. [PMID: 36233058 PMCID: PMC9569637 DOI: 10.3390/ijms231911759] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 09/29/2022] [Accepted: 09/30/2022] [Indexed: 11/17/2022] Open
Abstract
Motoneuron diseases (MNDs) are neurodegenerative conditions associated with death of upper and/or lower motoneurons (MNs). Proteostasis alteration is a pathogenic mechanism involved in many MNDs and is due to the excessive presence of misfolded and aggregated proteins. Protein misfolding may be the product of gene mutations, or due to defects in the translation process, or to stress agents; all these conditions may alter the native conformation of proteins making them prone to aggregate. Alternatively, mutations in members of the protein quality control (PQC) system may determine a loss of function of the proteostasis network. This causes an impairment in the capability to handle and remove aberrant or damaged proteins. The PQC system consists of the degradative pathways, which are the autophagy and the proteasome, and a network of chaperones and co-chaperones. Among these components, Heat Shock Protein 70 represents the main factor in substrate triage to folding, refolding, or degradation, and it is assisted in this task by a subclass of the chaperone network, the small heat shock protein (sHSPs/HSPBs) family. HSPBs take part in proteostasis by bridging misfolded and aggregated proteins to the HSP70 machinery and to the degradative pathways, facilitating refolding or clearance of the potentially toxic proteins. Because of its activity against proteostasis alteration, the chaperone system plays a relevant role in the protection against proteotoxicity in MNDs. Here, we discuss the role of HSPBs in MNDs and which HSPBs may represent a valid target for therapeutic purposes.
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25
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Liu Y, Iqbal A, Li W, Ni Z, Wang Y, Ramprasad J, Abraham KJ, Zhang M, Zhao DY, Qin S, Loppnau P, Jiang H, Guo X, Brown PJ, Zhen X, Xu G, Mekhail K, Ji X, Bedford MT, Greenblatt JF, Min J. A small molecule antagonist of SMN disrupts the interaction between SMN and RNAP II. Nat Commun 2022; 13:5453. [PMID: 36114190 PMCID: PMC9481570 DOI: 10.1038/s41467-022-33229-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 09/05/2022] [Indexed: 11/09/2022] Open
Abstract
Survival of motor neuron (SMN) functions in diverse biological pathways via recognition of symmetric dimethylarginine (Rme2s) on proteins by its Tudor domain, and deficiency of SMN leads to spinal muscular atrophy. Here we report a potent and selective antagonist with a 4-iminopyridine scaffold targeting the Tudor domain of SMN. Our structural and mutagenesis studies indicate that both the aromatic ring and imino groups of compound 1 contribute to its selective binding to SMN. Various on-target engagement assays support that compound 1 specifically recognizes SMN in a cellular context and prevents the interaction of SMN with the R1810me2s of RNA polymerase II subunit POLR2A, resulting in transcription termination and R-loop accumulation mimicking SMN depletion. Thus, in addition to the antisense, RNAi and CRISPR/Cas9 techniques, potent SMN antagonists could be used as an efficient tool to understand the biological functions of SMN.
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Affiliation(s)
- Yanli Liu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China.
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, China.
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada.
| | - Aman Iqbal
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
| | - Weiguo Li
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, China
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
| | - Zuyao Ni
- Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Yalong Wang
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jurupula Ramprasad
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Karan Joshua Abraham
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Mengmeng Zhang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | | | - Su Qin
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
- Life Science Research Center, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Peter Loppnau
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
| | - Honglv Jiang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Xinghua Guo
- Donnelly Centre, University of Toronto, Toronto, ON, Canada
| | - Peter J Brown
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada
| | - Xuechu Zhen
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Guoqiang Xu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Karim Mekhail
- Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Xingyue Ji
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Mark T Bedford
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Jinrong Min
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, China.
- Structural Genomics Consortium, University of Toronto, Toronto, ON, Canada.
- Department of Physiology, University of Toronto, Toronto, ON, Canada.
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26
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Sun J, Qiu J, Yang Q, Ju Q, Qu R, Wang X, Wu L, Xing L. Single-cell RNA sequencing reveals dysregulation of spinal cord cell types in a severe spinal muscular atrophy mouse model. PLoS Genet 2022; 18:e1010392. [PMID: 36074806 PMCID: PMC9488758 DOI: 10.1371/journal.pgen.1010392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 09/20/2022] [Accepted: 08/23/2022] [Indexed: 11/18/2022] Open
Abstract
Although spinal muscular atrophy (SMA) is a motor neuron disease caused by the loss of survival of motor neuron (SMN) proteins, there is growing evidence that non-neuronal cells play important roles in SMA pathogenesis. However, transcriptome alterations occurring at the single-cell level in SMA spinal cord remain unknown, preventing us from fully comprehending the role of specific cells. Here, we performed single-cell RNA sequencing of the spinal cord of a severe SMA mouse model, and identified ten cell types as well as their differentially expressed genes. Using CellChat, we found that cellular communication between different cell types in the spinal cord of SMA mice was significantly reduced. A dimensionality reduction analysis revealed 29 cell subtypes and their differentially expressed gene. A subpopulation of vascular fibroblasts showed the most significant change in the SMA spinal cord at the single-cell level. This subpopulation was drastically reduced, possibly causing vascular defects and resulting in widespread protein synthesis and energy metabolism reductions in SMA mice. This study reveals for the first time a single-cell atlas of the spinal cord of mice with severe SMA, and sheds new light on the pathogenesis of SMA.
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Affiliation(s)
- Junjie Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
- * E-mail: (JS); (LW); (LX)
| | - Jiaying Qiu
- Department of Prenatal Screening and Diagnosis Center, Affiliated Maternity and Child Health Care Hospital of Nantong University, Nantong, China
| | - Qiongxia Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
| | - Qianqian Ju
- Laboratory Animal Center, Nantong University, Nantong, China
| | - Ruobing Qu
- Biomedical Polymers Laboratory, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China
| | - Xu Wang
- Laboratory Animal Center, Nantong University, Nantong, China
| | - Liucheng Wu
- Laboratory Animal Center, Nantong University, Nantong, China
- * E-mail: (JS); (LW); (LX)
| | - Lingyan Xing
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Nantong University, Nantong, China
- * E-mail: (JS); (LW); (LX)
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27
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Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in SMN1 (encoding survival motor neuron protein (SMN)). Reduced expression of SMN leads to loss of α-motor neurons, severe muscle weakness and often early death. Standard-of-care recommendations for multidisciplinary supportive care of SMA were established in the past few decades. However, improved understanding of the pathogenetic mechanisms of SMA has led to the development of different therapeutic approaches. Three treatments that increase SMN expression by distinct molecular mechanisms, administration routes and tissue biodistributions have received regulatory approval with others in clinical development. The advent of the new therapies is redefining standards of care as in many countries most patients are treated with one of the new therapies, leading to the identification of emerging new phenotypes of SMA and a renewed characterization of demographics owing to improved patient survival.
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28
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Cuartas J, Gangwani L. R-loop Mediated DNA Damage and Impaired DNA Repair in Spinal Muscular Atrophy. Front Cell Neurosci 2022; 16:826608. [PMID: 35783101 PMCID: PMC9243258 DOI: 10.3389/fncel.2022.826608] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 05/23/2022] [Indexed: 12/02/2022] Open
Abstract
Defects in DNA repair pathways are a major cause of DNA damage accumulation leading to genomic instability and neurodegeneration. Efficient DNA damage repair is critical to maintain genomicstability and support cell function and viability. DNA damage results in the activation of cell death pathways, causing neuronal death in an expanding spectrum of neurological disorders, such as amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD), Alzheimer’s disease (AD), and spinal muscular atrophy (SMA). SMA is a neurodegenerative disorder caused by mutations in the Survival Motor Neuron 1 (SMN1) gene. SMA is characterized by the degeneration of spinal cord motor neurons due to low levels of the SMN protein. The molecular mechanism of selective motor neuron degeneration in SMA was unclear for about 20 years. However, several studies have identified biochemical and molecular mechanisms that may contribute to the predominant degeneration of motor neurons in SMA, including the RhoA/ROCK, the c-Jun NH2-terminal kinase (JNK), and p53-mediated pathways, which are involved in mediating DNA damage-dependent cell death. Recent studies provided insight into selective degeneration of motor neurons, which might be caused by accumulation of R-loop-mediated DNA damage and impaired non-homologous end joining (NHEJ) DNA repair pathway leading to genomic instability. Here, we review the latest findings involving R-loop-mediated DNA damage and defects in neuron-specific DNA repair mechanisms in SMA and discuss these findings in the context of other neurodegenerative disorders linked to DNA damage.
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Affiliation(s)
- Juliana Cuartas
- Center of Emphasis in Neurosciences, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences, Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
- Francis Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, United States
- *Correspondence: Laxman Gangwani
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29
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Lambert-Smith IA, Saunders DN, Yerbury JJ. Progress in biophysics and molecular biology proteostasis impairment and ALS. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 174:3-27. [PMID: 35716729 DOI: 10.1016/j.pbiomolbio.2022.06.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 05/19/2022] [Accepted: 06/09/2022] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal neurodegenerative disease that results from the loss of both upper and lower motor neurons. It is the most common motor neuron disease and currently has no effective treatment. There is mounting evidence to suggest that disturbances in proteostasis play a significant role in ALS pathogenesis. Proteostasis is the maintenance of the proteome at the right level, conformation and location to allow a cell to perform its intended function. In this review, we present a thorough synthesis of the literature that provides evidence that genetic mutations associated with ALS cause imbalance to a proteome that is vulnerable to such pressure due to its metastable nature. We propose that the mechanism underlying motor neuron death caused by defects in mRNA metabolism and protein degradation pathways converges on proteostasis dysfunction. We propose that the proteostasis network may provide an effective target for therapeutic development in ALS.
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Affiliation(s)
- Isabella A Lambert-Smith
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Darren N Saunders
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
| | - Justin J Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia; Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia.
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30
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Rudzka M, Wróblewska-Ankiewicz P, Majewska K, Hyjek-Składanowska M, Gołębiewski M, Sikora M, Smoliński DJ, Kołowerzo-Lubnau A. Functional nuclear retention of pre-mRNA involving Cajal bodies during meiotic prophase in European larch (Larix decidua). THE PLANT CELL 2022; 34:2404-2423. [PMID: 35294035 PMCID: PMC9134060 DOI: 10.1093/plcell/koac091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
Gene regulation ensures that the appropriate genes are expressed at the proper time. Nuclear retention of incompletely spliced or mature mRNAs is emerging as a novel, previously underappreciated layer of posttranscriptional regulation. Studies on this phenomenon indicated that it exerts a significant influence on the regulation of gene expression by regulating export and translation delay, which allows the synthesis of specific proteins in response to a stimulus or at strictly controlled time points, for example, during cell differentiation or development. Here, we show that transcription in microsporocytes of European larch (Larix decidua) occurs in a pulsatile manner during prophase of the first meiotic division. Transcriptional activity was then silenced after each pulse. However, the transcripts synthesized were not exported immediately to the cytoplasm but were retained in the nucleoplasm and Cajal bodies (CBs). In contrast to the nucleoplasm, we did not detect mature transcripts in CBs, which only stored nonfully spliced transcripts with retained introns. Notably, the retained introns were spliced at precisely defined times, and fully mature mRNAs were released into the cytoplasm for translation. As similar processes have been observed during spermatogenesis in animals, our results illustrate an evolutionarily conserved mechanism of gene expression regulation during generative cells development in Eukaryota.
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Affiliation(s)
- Magda Rudzka
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Torun 87-100, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
| | - Patrycja Wróblewska-Ankiewicz
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Torun 87-100, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
| | - Karolina Majewska
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Torun 87-100, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
| | | | - Marcin Gołębiewski
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
- Department of Plant Physiology and Biotechnology, Nicolaus Copernicus University, Torun 87-100, Poland
| | - Marcin Sikora
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
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31
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Kim JH, Kang JS, Yoo K, Jeong J, Park I, Park JH, Rhee J, Jeon S, Jo YW, Hann SH, Seo M, Moon S, Um SJ, Seong RH, Kong YY. Bap1/SMN axis in Dpp4+ skeletal muscle mesenchymal cells regulates the neuromuscular system. JCI Insight 2022; 7:158380. [PMID: 35603786 PMCID: PMC9220848 DOI: 10.1172/jci.insight.158380] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/06/2022] [Indexed: 12/15/2022] Open
Abstract
The survival of motor neuron (SMN) protein is a major component of the pre-mRNA splicing machinery and is required for RNA metabolism. Although SMN has been considered a fundamental gene for the central nervous system, due to its relationship with neuromuscular diseases, such as spinal muscular atrophy, recent studies have also revealed the requirement of SMN in non-neuronal cells in the peripheral regions. Here, we report that the fibro-adipogenic progenitor subpopulation expressing Dpp4 (Dpp4+ FAPs) is required for the neuromuscular system. Furthermore, we also reveal that BRCA1-associated protein-1 (Bap1) is crucial for the stabilization of SMN in FAPs by preventing its ubiquitination-dependent degradation. Inactivation of Bap1 in FAPs decreased SMN levels and accompanied degeneration of the neuromuscular junction, leading to loss of motor neurons and muscle atrophy. Overexpression of the ubiquitination-resistant SMN variant, SMNK186R, in Bap1-null FAPs completely prevented neuromuscular degeneration. In addition, transplantation of Dpp4+ FAPs, but not Dpp4– FAPs, completely rescued neuromuscular defects. Our data reveal the crucial role of Bap1-mediated SMN stabilization in Dpp4+ FAPs for the neuromuscular system and provide the possibility of cell-based therapeutics to treat neuromuscular diseases.
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Affiliation(s)
- Ji-Hoon Kim
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Molecular Recognition Research Center, Korea Institute of Science and Technology, Seoul, South Korea
| | - Jong-Seol Kang
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Kyusang Yoo
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Jinguk Jeong
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Inkuk Park
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Jong Ho Park
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Joonwoo Rhee
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Shin Jeon
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Young-Woo Jo
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Sang-Hyeon Hann
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Minji Seo
- School of Biological Sciences, Seoul National University, Seoul, South Korea
| | - Seungtae Moon
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea
| | - Soo-Jong Um
- Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea
| | - Rho Hyun Seong
- School of Biological Sciences, Seoul National University, Seoul, South Korea
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, South Korea
| | - Young-Yun Kong
- School of Biological Sciences, Seoul National University, Seoul, South Korea
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32
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Bizen N, Bepari AK, Zhou L, Abe M, Sakimura K, Ono K, Takebayashi H. Ddx20, an Olig2 binding factor, governs the survival of neural and oligodendrocyte progenitor cells via proper Mdm2 splicing and p53 suppression. Cell Death Differ 2022; 29:1028-1041. [PMID: 34974536 PMCID: PMC9090832 DOI: 10.1038/s41418-021-00915-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 09/05/2021] [Accepted: 09/20/2021] [Indexed: 12/13/2022] Open
Abstract
Olig2 is indispensable for motoneuron and oligodendrocyte fate-specification in the pMN domain of embryonic spinal cords, and also involved in the proliferation and differentiation of several cell types in the nervous system, including neural progenitor cells (NPCs) and oligodendrocytes. However, how Olig2 controls these diverse biological processes remains unclear. Here, we demonstrated that a novel Olig2-binding protein, DEAD-box helicase 20 (Ddx20), is indispensable for the survival of NPCs and oligodendrocyte progenitor cells (OPCs). A central nervous system (CNS)-specific Ddx20 conditional knockout (cKO) demonstrated apoptosis and cell cycle arrest in NPCs and OPCs, through the potentiation of the p53 pathway in DNA damage-dependent and independent manners, including SMN complex disruption and the abnormal splicing of Mdm2 mRNA. Analyzes of Olig2 null NPCs showed that Olig2 contributed to NPC proliferation through Ddx20 protein stabilization. Our findings provide novel mechanisms underlying the Olig2-mediated proliferation of NPCs, via the Ddx20-p53 axis, in the embryonic CNS.
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Affiliation(s)
- Norihisa Bizen
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Asim K Bepari
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.,Department of Pharmaceutical Sciences, North South University, Dhaka, Bangladesh
| | - Li Zhou
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan.,Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan.,Center for Coordination of Research Facilities (CCRF), Niigata University, Niigata, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan.,Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, Japan.,Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata, Japan
| | - Katsuhiko Ono
- Developmental Neurobiology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hirohide Takebayashi
- Division of Neurobiology and Anatomy, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan. .,Center for Coordination of Research Facilities (CCRF), Niigata University, Niigata, Japan.
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33
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Jacquier V, Prévot M, Gostan T, Bordonné R, Benkhelifa-Ziyyat S, Barkats M, Soret J. Splicing efficiency of minor introns in a mouse model of SMA predominantly depends on their branchpoint sequence and can involve the contribution of major spliceosome components. RNA (NEW YORK, N.Y.) 2022; 28:303-319. [PMID: 34893560 PMCID: PMC8848931 DOI: 10.1261/rna.078329.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
Spinal muscular atrophy (SMA) is a devastating neurodegenerative disease caused by reduced amounts of the ubiquitously expressed Survival of Motor Neuron (SMN) protein. In agreement with its crucial role in the biogenesis of spliceosomal snRNPs, SMN-deficiency is correlated to numerous splicing alterations in patient cells and various tissues of SMA mouse models. Among the snRNPs whose assembly is impacted by SMN-deficiency, those involved in the minor spliceosome are particularly affected. Importantly, splicing of several, but not all U12-dependent introns has been shown to be affected in different SMA models. Here, we have investigated the molecular determinants of this differential splicing in spinal cords from SMA mice. We show that the branchpoint sequence (BPS) is a key element controlling splicing efficiency of minor introns. Unexpectedly, splicing of several minor introns with suboptimal BPS is not affected in SMA mice. Using in vitro splicing experiments and oligonucleotides targeting minor or major snRNAs, we show for the first time that splicing of these introns involves both the minor and major machineries. Our results strongly suggest that splicing of a subset of minor introns is not affected in SMA mice because components of the major spliceosome compensate for the loss of minor splicing activity.
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Affiliation(s)
- Valentin Jacquier
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Manon Prévot
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Thierry Gostan
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Rémy Bordonné
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Sofia Benkhelifa-Ziyyat
- Centre de Recherche en Myologie (CRM), Institut de Myologie, Sorbonne Universités, UPMC Univ Paris 06, Inserm UMRS974, GH Pitié Salpêtrière, Paris 75013, France
| | - Martine Barkats
- Centre de Recherche en Myologie (CRM), Institut de Myologie, Sorbonne Universités, UPMC Univ Paris 06, Inserm UMRS974, GH Pitié Salpêtrière, Paris 75013, France
| | - Johann Soret
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
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34
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Li W, Jiang C, Zhang E. Advances in the phase separation-organized membraneless organelles in cells: a narrative review. Transl Cancer Res 2022; 10:4929-4946. [PMID: 35116344 PMCID: PMC8797891 DOI: 10.21037/tcr-21-1111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/29/2021] [Indexed: 11/26/2022]
Abstract
Membraneless organelles (MLOs) are micro-compartments that lack delimiting membranes, concentrating several macro-molecules with a high local concentration in eukaryotic cells. Recent studies have shown that MLOs have pivotal roles in multiple biological processes, including gene transcription, RNA metabolism, translation, protein modification, and signal transduction. These biological processes in cells have essential functions in many diseases, such as cancer, neurodegenerative diseases, and virus-related diseases. The liquid-liquid phase separation (LLPS) microenvironment within cells is thought to be the driving force for initiating the formation of micro-compartments with a liquid-like property, becoming an important organizing principle for MLOs to mediate organism responses. In this review, we comprehensively elucidated the formation of these MLOs and the relationship between biological functions and associated diseases. The mechanisms underlying the influence of protein concentration and valency on phase separation in cells are also discussed. MLOs undergoing the LLPS process have diverse functions, including stimulation of some adaptive and reversible responses to alter the transcriptional or translational processes, regulation of the concentrations of biomolecules in living cells, and maintenance of cell morphogenesis. Finally, we highlight that the development of this field could pave the way for developing novel therapeutic strategies for the treatment of LLPS-related diseases based on the understanding of phase separation in the coming years.
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Affiliation(s)
- Weihan Li
- Department of Immunology, School of Medicine, Nantong University, Nantong, China
| | - Chenwei Jiang
- Department of Immunology, School of Medicine, Nantong University, Nantong, China
| | - Erhao Zhang
- Department of Immunology, School of Medicine, Nantong University, Nantong, China.,Laboratory of Medical Science, School of Medicine, Nantong University, Nantong, China
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35
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Dominguez CE, Cunningham D, Venkataramany AS, Chandler DS. Heat increases full-length SMN splicing: promise for splice-augmenting therapies for SMA. Hum Genet 2022; 141:239-256. [PMID: 35088120 DOI: 10.1007/s00439-021-02408-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/30/2021] [Indexed: 11/28/2022]
Abstract
Spinal muscular atrophy (SMA) is a debilitating neurodegenerative pediatric disease characterized by low levels of the survival motor protein (SMN). Humans have two SMN genes that produce identical SMN proteins, but they differ at a key nucleotide in exon 7 that induces differential mRNA splicing. SMN1 primarily produces full-length SMN protein, but due to the spliceosome's inability to efficiently recognize exon 7, SMN2 transcripts are often truncated. SMA occurs primarily through mutations or deletions in the SMN1 gene; therefore, current therapies use antisense oligonucleotides (ASOs) to target exon 7 inclusion in SMN2 mRNA and promote full-length SMN protein production. Here, we explore additional methods that can target SMN splicing and therapeutically increase full-length SMN protein. We demonstrate that in vitro heat treatment of cells increases exon 7 inclusion and relative abundance of full-length SMN2 mRNA and protein, a response that is modulated through the upregulation of the positive splicing factor TRA2 beta. We also observe that HSP90, but not HSP40 or HSP70, in the heat shock response is essential for SMN2 exon 7 splicing under hyperthermic conditions. Finally, we show that pulsatile heat treatments for one hour in vitro and in vivo are effective in increasing full-length SMN2 levels. These findings suggest that timed interval treatments could be a therapeutic alternative for SMA patients who do not respond to current ASO-based therapies or require a unique combination regimen.
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Affiliation(s)
- Catherine E Dominguez
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA.,Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - David Cunningham
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA
| | - Akila S Venkataramany
- Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA.,Biomedical Sciences Graduate Program, The Ohio State University, Columbus, OH, USA.,Medical Scientist Training Program, The Ohio State University, Columbus, OH, USA
| | - Dawn S Chandler
- Molecular, Cellular and Developmental Biology Graduate Program and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA. .,Center for Childhood Cancer and Blood Diseases, The Research Institute at Nationwide Children's Hospital, 700 Children's Drive, Columbus, OH, 43205, USA. .,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA.
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36
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Kannan A, Cuartas J, Gangwani P, Branzei D, Gangwani L. Mutation in senataxin alters the mechanism of R-loop resolution in amyotrophic lateral sclerosis 4. Brain 2022; 145:3072-3094. [PMID: 35045161 PMCID: PMC9536298 DOI: 10.1093/brain/awab464] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/08/2021] [Accepted: 12/03/2021] [Indexed: 11/22/2022] Open
Abstract
Mutation in the senataxin (SETX) gene causes an autosomal dominant neuromuscular disorder, amyotrophic lateral sclerosis 4 (ALS4), characterized by degeneration of motor neurons, muscle weakness and atrophy. SETX is an RNA-DNA helicase that mediates resolution of co-transcriptional RNA:DNA hybrids (R-loops). The process of R-loop resolution is essential for the normal functioning of cells, including neurons. The molecular basis of ALS4 pathogenesis and the mechanism of R-loop resolution are unclear. We report that the zinc finger protein ZPR1 binds to RNA:DNA hybrids, recruits SETX onto R-loops and is critical for R-loop resolution. ZPR1 deficiency disrupts the integrity of R-loop resolution complexes containing SETX and causes increased R-loop accumulation throughout gene transcription. We uncover that SETX is a downstream target of ZPR1 and that overexpression of ZPR1 can rescue R-loop resolution complexe assembly in SETX-deficient cells but not vice versa. To uncover the mechanism of R-loop resolution, we examined the function of SETX-ZPR1 complexes using two genetic motor neuron disease models with altered R-loop resolution. Notably, chronic low levels of SETX-ZPR1 complexes onto R-loops result in a decrease of R-loop resolution activity causing an increase in R-loop levels in spinal muscular atrophy. ZPR1 overexpression increases recruitment of SETX onto R-loops, decreases R-loops and rescues the spinal muscular atrophy phenotype in motor neurons and patient cells. Strikingly, interaction of SETX with ZPR1 is disrupted in ALS4 patients that have heterozygous SETX (L389S) mutation. ZPR1 fails to recruit the mutant SETX homodimer but recruits the heterodimer with partially disrupted interaction between SETX and ZPR1. Interestingly, disruption of SETX-ZPR1 complexes causes increase in R-loop resolution activity leading to fewer R-loops in ALS4. Modulation of ZPR1 levels regulates R-loop accumulation and rescues the pathogenic R-loop phenotype in ALS4 patient cells. These findings originate a new concept, ‘opposite alterations in a cell biological activity (R-loop resolution) result in similar pathogenesis (neurodegeneration) in different genetic motor neuron disorders’. We propose that ZPR1 collaborates with SETX and may function as a molecular brake to regulate SETX-dependent R-loop resolution activity critical for the normal functioning of motor neurons.
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Affiliation(s)
- Annapoorna Kannan
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
- Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
| | - Juliana Cuartas
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
- Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
| | - Pratik Gangwani
- Automated Driving Compute System Architecture, GM Global Technical Center - Sloan Engineering Center, Warren, Michigan 48092, USA
| | - Dana Branzei
- The FIRC Institute of Molecular Oncology Foundation, IFOM Foundation, Via Adamello 16, Milan 20139, Italy
- Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100, Pavia, Italy
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
- Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, Texas 79905, USA
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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.
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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.
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38
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Varderidou-Minasian S, Verheijen BM, Harschnitz O, Kling S, Karst H, van der Pol WL, Pasterkamp RJ, Altelaar M. Spinal Muscular Atrophy Patient iPSC-Derived Motor Neurons Display Altered Proteomes at Early Stages of Differentiation. ACS OMEGA 2021; 6:35375-35388. [PMID: 34984269 PMCID: PMC8717385 DOI: 10.1021/acsomega.1c04688] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/24/2021] [Indexed: 05/08/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neurodegenerative disorder characterized by loss of motor neurons (MN) in the spinal cord leading to progressive muscle atrophy and weakness. SMA is caused by mutations in the survival motor neuron 1 (SMN1) gene, resulting in reduced levels of survival motor neuron (SMN) protein. The mechanisms that link SMN deficiency to selective motor neuron dysfunction in SMA remain largely unknown. We present here, for the first time, a comprehensive quantitative TMT-10plex proteomics analysis that covers the development of induced pluripotent stem cell-derived MNs from both healthy individuals and SMA patients. We show that the proteomes of SMA samples segregate from controls already at early stages of neuronal differentiation. The altered proteomic signature in SMA MNs is associated with mRNA splicing, ribonucleoprotein biogenesis, organelle organization, cellular biogenesis, and metabolic processes. We highlight several known SMN-binding partners and evaluate their expression changes during MN differentiation. In addition, we compared our study to human and mouse in vivo proteomic studies revealing distinct and similar signatures. Altogether, our work provides a comprehensive resource of molecular events during early stages of MN differentiation, containing potentially therapeutically interesting protein expression profiles for SMA.
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Affiliation(s)
- Suzy Varderidou-Minasian
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584
CH Utrecht, The Netherlands
- Netherlands
Proteomics Center, Padualaan
8, 3584 CH Utrecht, The Netherlands
| | - Bert M. Verheijen
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Oliver Harschnitz
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Sandra Kling
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - Henk Karst
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - W. Ludo van der Pol
- Department
of Neurology and Neurosurgery, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, The Netherlands
| | - R. Jeroen Pasterkamp
- Department
of Translational Neuroscience, UMC Utrecht Brain Center, University
Medical Center Utrecht, Utrecht University, 3584 CG Utrecht, The Netherlands
| | - Maarten Altelaar
- Biomolecular
Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular
Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, 3584
CH Utrecht, The Netherlands
- Netherlands
Proteomics Center, Padualaan
8, 3584 CH Utrecht, The Netherlands
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39
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Genetic architecture of motor neuron diseases. J Neurol Sci 2021; 434:120099. [PMID: 34965490 DOI: 10.1016/j.jns.2021.120099] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 11/26/2021] [Accepted: 12/14/2021] [Indexed: 12/18/2022]
Abstract
Motor neuron diseases (MNDs) are rare and frequently fatal neurological disorders in which motor neurons within the brainstem and spinal cord regions slowly die. MNDs are primarily caused by genetic mutations, and > 100 different mutant genes in humans have been discovered thus far. Given the fact that many more MND-related genes have yet to be discovered, the growing body of genetic evidence has offered new insights into the diverse cellular and molecular mechanisms involved in the aetiology and pathogenesis of MNDs. This search may aid in the selection of potential candidate genes for future investigation and, eventually, may open the door to novel interventions to slow down disease progression. In this review paper, we have summarized detailed existing research findings of different MNDs, such as amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), spinal bulbar muscle atrophy (SBMA) and hereditary spastic paraplegia (HSP) in relation to their complex genetic architecture.
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Buettner JM, Sime Longang JK, Gerstner F, Apel KS, Blanco-Redondo B, Sowoidnich L, Janzen E, Langenhan T, Wirth B, Simon CM. Central synaptopathy is the most conserved feature of motor circuit pathology across spinal muscular atrophy mouse models. iScience 2021; 24:103376. [PMID: 34825141 PMCID: PMC8605199 DOI: 10.1016/j.isci.2021.103376] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/12/2021] [Accepted: 10/26/2021] [Indexed: 11/04/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by reduced survival motor neuron (SMN) protein. Recently, SMN dysfunction has been linked to individual aspects of motor circuit pathology in a severe SMA mouse model. To determine whether these disease mechanisms are conserved, we directly compared the motor circuit pathology of three SMA mouse models. The severe SMNΔ7 model exhibits vast motor circuit defects, including degeneration of motor neurons, spinal excitatory synapses, and neuromuscular junctions (NMJs). In contrast, the Taiwanese model shows very mild motor neuron pathology, but early central synaptic loss. In the intermediate Smn2B/- model, strong pathology of central excitatory synapses and NMJs precedes the late onset of p53-dependent motor neuron death. These pathological events correlate with SMN-dependent splicing dysregulation of specific mRNAs. Our study provides a knowledge base for properly tailoring future studies and identifies central excitatory synaptopathy as a key feature of motor circuit pathology in SMA. Comparison of detailed motor circuit pathology across three SMA mouse models Motor circuit pathology correlates with dysregulation of specific mRNAs Motor neuron death in severe and intermediate SMA models is p53-dependent Central excitatory synaptopathy is the most conserved feature of SMA pathology
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Affiliation(s)
- Jannik M Buettner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | | | - Florian Gerstner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | - Katharina S Apel
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | - Beatriz Blanco-Redondo
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig 04103, Germany
| | - Leonie Sowoidnich
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | - Eva Janzen
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Tobias Langenhan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig 04103, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Rare Diseases Cologne, University Hospital of Cologne, Cologne, Germany
| | - Christian M Simon
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
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41
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Ravel-Chapuis A, Haghandish A, Daneshvar N, Jasmin BJ, Côté J. A novel CARM1-HuR axis involved in muscle differentiation and plasticity misregulated in spinal muscular atrophy. Hum Mol Genet 2021; 31:1453-1470. [PMID: 34791230 DOI: 10.1093/hmg/ddab333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 10/19/2021] [Accepted: 10/19/2021] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is characterized by the loss of alpha motor neurons in the spinal cord and a progressive muscle weakness and atrophy. SMA is caused by loss-of-function mutations and/or deletions in the survival of motor neuron (SMN) gene. The role of SMN in motor neurons has been extensively studied, but its function and the consequences of its loss in muscle has also emerged as a key aspect of SMA pathology. In this study, we explore the molecular mechanisms involved in muscle defects in SMA. First, we show in C2C12 myoblasts, that arginine methylation by CARM1 controls myogenic differentiation. More specifically, the methylation of HuR on K217 regulates HuR levels and subcellular localization during myogenic differentiation, and the formation of myotubes. Furthermore, we demonstrate that SMN and HuR interact in C2C12 myoblasts. Interestingly, the SMA-causing E134K point mutation within the SMN Tudor domain, and CARM1 depletion, modulate the SMN-HuR interaction. In addition, using the Smn2B/- mouse model, we report that CARM1 levels are markedly increased in SMA muscles and that HuR fails to properly respond to muscle denervation, thereby affecting the regulation of its mRNA targets. Altogether, our results show a novel CARM1-HuR axis in the regulation of muscle differentiation and plasticity as well as in the aberrant regulation of this axis caused by the absence of SMN in SMA muscle. With the recent developments of therapeutics targeting motor neurons, this study further indicates the need for more global therapeutic approaches for SMA.
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Affiliation(s)
- Aymeric Ravel-Chapuis
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Amir Haghandish
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Nasibeh Daneshvar
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON K1H 8M5, Canada
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42
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Mabin JW, Lewis PW, Brow DA, Dvinge H. Human spliceosomal snRNA sequence variants generate variant spliceosomes. RNA (NEW YORK, N.Y.) 2021; 27:1186-1203. [PMID: 34234030 PMCID: PMC8457000 DOI: 10.1261/rna.078768.121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 06/29/2021] [Indexed: 06/02/2023]
Abstract
Human pre-mRNA splicing is primarily catalyzed by the major spliceosome, comprising five small nuclear ribonucleoprotein complexes, U1, U2, U4, U5, and U6 snRNPs, each of which contains the corresponding U-rich snRNA. These snRNAs are encoded by large gene families exhibiting significant sequence variation, but it remains unknown if most human snRNA genes are untranscribed pseudogenes or produce variant snRNAs with the potential to differentially influence splicing. Since gene duplication and variation are powerful mechanisms of evolutionary adaptation, we sought to address this knowledge gap by systematically profiling human U1, U2, U4, and U5 snRNA variant gene transcripts. We identified 55 transcripts that are detectably expressed in human cells, 38 of which incorporate into snRNPs and spliceosomes in 293T cells. All U1 snRNA variants are more than 1000-fold less abundant in spliceosomes than the canonical U1, whereas at least 1% of spliceosomes contain a variant of U2 or U4. In contrast, eight U5 snRNA sequence variants occupy spliceosomes at levels of 1% to 46%. Furthermore, snRNA variants display distinct expression patterns across five human cell lines and adult and fetal tissues. Different RNA degradation rates contribute to the diverse steady state levels of snRNA variants. Our findings suggest that variant spliceosomes containing noncanonical snRNAs may contribute to different tissue- and cell-type-specific alternative splicing patterns.
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Affiliation(s)
- Justin W Mabin
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| | - Peter W Lewis
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| | - David A Brow
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
| | - Heidi Dvinge
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706, USA
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43
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Choi K, Yang A, Baek J, Jeong H, Kang Y, Baek W, Kim JC, Kang M, Choi M, Ham Y, Son MJ, Han SB, Kim J, Jang JH, Ahn JS, Shen H, Woo SH, Kim JH, Cho S. Regulation of Survival Motor Neuron Gene Expression by Calcium Signaling. Int J Mol Sci 2021; 22:ijms221910234. [PMID: 34638572 PMCID: PMC8508836 DOI: 10.3390/ijms221910234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/07/2021] [Accepted: 09/16/2021] [Indexed: 11/21/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by homozygous survival of motor neurons 1 (SMN1) gene deletion, leaving a duplicate gene, SMN2, as the sole source of SMN protein. However, a defect in SMN2 splicing, involving exon 7 skipping, results in a low level of functional SMN protein. Therefore, the upregulation of SMN protein expression from the SMN2 gene is generally considered to be one of the best therapeutic strategies to treat SMA. Most of the SMA drug discovery is based on synthetic compounds, and very few natural compounds have been explored thus far. Here, we performed an unbiased mechanism-independent and image-based screen of a library of microbial metabolites in SMA fibroblasts using an SMN-specific immunoassay. In doing so, we identified brefeldin A (BFA), a well-known inhibitor of ER-Golgi protein trafficking, as a strong inducer of SMN protein. The profound increase in SMN protein was attributed to, in part, the rescue of the SMN2 pre-mRNA splicing defect. Intriguingly, BFA increased the intracellular calcium concentration, and the BFA-induced exon 7 inclusion of SMN2 splicing, was abrogated by the depletion of intracellular calcium and by the pharmacological inhibition of calcium/calmodulin-dependent kinases (CaMKs). Moreover, BFA considerably reduced the expression of Tra2-β and SRSF9 proteins in SMA fibroblasts and enhanced the binding of PSF and hnRNP M to an exonic splicing enhancer (ESE) of exon 7. Together, our results demonstrate a significant role for calcium and its signaling on the regulation of SMN splicing, probably through modulating the expression/activity of splicing factors.
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Affiliation(s)
- Kwangman Choi
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Medical Biotechnology, SoonChunHyang University, Asan 31538, Korea
| | - Ansook Yang
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Jiyeon Baek
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Hyejeong Jeong
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Yura Kang
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
| | - Woosun Baek
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
| | - Joon-Chul Kim
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
| | - Mingu Kang
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Miri Choi
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Youngwook Ham
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
| | - Min-Jeong Son
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
| | - Sang-Bae Han
- College of Pharmacy, Chungbuk National University, Cheongju 28160, Korea;
| | - Janghwan Kim
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea;
| | - Jae-Hyuk Jang
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea
| | - Jong Seog Ahn
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Anticancer Agent Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea
| | - Haihong Shen
- Gwangju Institute of Science and Technology, School of life Sciences, Gwangju 61005, Korea;
| | - Sun-Hee Woo
- College of Pharmacy, Chungnam National University, Daejeon 34134, Korea; (J.-C.K.); (M.-J.S.)
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
| | - Jong Heon Kim
- Department of Cancer Biomedical Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang 10408, Korea; (Y.K.); (W.B.)
- Cancer Molecular Biology Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang 10408, Korea
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
| | - Sungchan Cho
- Natural Medicine Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (K.C.); (A.Y.); (J.B.); (H.J.); (M.K.); (M.C.); (Y.H.)
- Department of Biomolecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea; (J.-H.J.); (J.S.A.)
- Correspondence: (S.-H.W.); (J.H.K.); (S.C.); Tel.: +82-42-821-5924 (S.-H.W.); +82-31-920-2204 (J.H.K.); +82-43-240-6105 (S.C.); Fax: +82-42-823-6566 (S.-H.W.); +82-31-920-2006 (J.H.K.); +82-43-240-6159 (S.C)
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Abstract
Autosomal-recessive spinal muscular atrophy (SMA) is characterized by the loss of specific motor neurons of the spinal cord and skeletal muscle atrophy. SMA is caused by mutations or deletions of the survival motor neuron 1 (SMN1) gene, and disease severity correlates with the expression levels of the nearly identical copy gene, SMN2. Both genes ubiquitously express SMN protein, but SMN2 generates only low levels of protein that do not fully compensate for the loss-of-function of SMN1. SMN protein forms a multiprotein complex essential for the cellular assembly of ribonucleoprotein particles involved in diverse aspects of RNA metabolism. Other studies using animal models revealed a spatio-temporal requirement of SMN that is high during the development of the neuromuscular system and later, in the general maintenance of cellular and tissues homeostasis. These observations define a period for maximum therapeutic efficiency of SMN restoration, and suggest that cells outside the central nervous system may also participate in the pathogenesis of SMA. Finally, recent innovative therapies have been shown to mitigate SMN deficiency and have been approved to treat SMA patients. We briefly review major findings from the past twenty-five years of SMA research. © 2020 French Society of Pediatrics. Published by Elsevier Masson SAS. All rights reserved.
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Affiliation(s)
- S Lefebvre
- T3S INSERM UMR 1124, Toxicité Environnementale, Cibles Thérapeutiques, Signalisation Cellulaire et Biomarqueurs, UFR des Sciences Fondamentales et Biomédicales, Campus Saint-Germain-des-prés, Université de Paris, Paris, France.
| | - C Sarret
- Centre de compétence maladies rares des pathologies neuromusculaires, service de génétique médicale, Hôpital Estaing, CHU Clermont-Ferrand, France.
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Ottesen EW, Luo D, Singh NN, Singh RN. High Concentration of an ISS-N1-Targeting Antisense Oligonucleotide Causes Massive Perturbation of the Transcriptome. Int J Mol Sci 2021; 22:ijms22168378. [PMID: 34445083 PMCID: PMC8395096 DOI: 10.3390/ijms22168378] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/14/2021] [Accepted: 07/31/2021] [Indexed: 12/17/2022] Open
Abstract
Intronic splicing silencer N1 (ISS-N1) located within Survival Motor Neuron 2 (SMN2) intron 7 is the target of a therapeutic antisense oligonucleotide (ASO), nusinersen (Spinraza), which is currently being used for the treatment of spinal muscular atrophy (SMA), a leading genetic disease associated with infant mortality. The discovery of ISS-N1 as a promising therapeutic target was enabled in part by Anti-N1, a 20-mer ASO that restored SMN2 exon 7 inclusion by annealing to ISS-N1. Here, we analyzed the transcriptome of SMA patient cells treated with 100 nM of Anti-N1 for 30 h. Such concentrations are routinely used to demonstrate the efficacy of an ASO. While 100 nM of Anti-N1 substantially stimulated SMN2 exon 7 inclusion, it also caused massive perturbations in the transcriptome and triggered widespread aberrant splicing, affecting expression of essential genes associated with multiple cellular processes such as transcription, splicing, translation, cell signaling, cell cycle, macromolecular trafficking, cytoskeletal dynamics, and innate immunity. We validated our findings with quantitative and semiquantitative PCR of 39 candidate genes associated with diverse pathways. We also showed a substantial reduction in off-target effects with shorter ISS-N1-targeting ASOs. Our findings are significant for implementing better ASO design and dosing regimens of ASO-based drugs.
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46
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Meijboom KE, Volpato V, Monzón-Sandoval J, Hoolachan JM, Hammond SM, Abendroth F, de Jong OG, Hazell G, Ahlskog N, Wood MJ, Webber C, Bowerman M. Combining multiomics and drug perturbation profiles to identify muscle-specific treatments for spinal muscular atrophy. JCI Insight 2021; 6:e149446. [PMID: 34236053 PMCID: PMC8410072 DOI: 10.1172/jci.insight.149446] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 05/17/2021] [Indexed: 12/13/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by loss of survival motor neuron (SMN) protein. While SMN restoration therapies are beneficial, they are not a cure. We aimed to identify potentially novel treatments to alleviate muscle pathology combining transcriptomics, proteomics, and perturbational data sets. This revealed potential drug candidates for repurposing in SMA. One of the candidates, harmine, was further investigated in cell and animal models, improving multiple disease phenotypes, including lifespan, weight, and key molecular networks in skeletal muscle. Our work highlights the potential of multiple and parallel data-driven approaches for the development of potentially novel treatments for use in combination with SMN restoration therapies.
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Affiliation(s)
- Katharina E Meijboom
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Gene Therapy Center, University of Massachusetts Medical School, Worcester, Massachusetts, USA
| | - Viola Volpato
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,UK Dementia Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Jimena Monzón-Sandoval
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,UK Dementia Research Institute, Cardiff University, Cardiff, United Kingdom
| | | | - Suzan M Hammond
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Department of Paediatrics, John Radcliffe Hospital and.,MDUK Oxford Neuromuscular Centre, University of Oxford, United Kingdom
| | - Frank Abendroth
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, United Kingdom.,Institute of Chemistry, Philipps-University of Marburg, Marburg, Germany
| | - Olivier G de Jong
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Faculty of Science, Utrecht University, Utrecht, Netherlands
| | - Gareth Hazell
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Nina Ahlskog
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Department of Paediatrics, John Radcliffe Hospital and
| | - Matthew Ja Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Department of Paediatrics, John Radcliffe Hospital and.,MDUK Oxford Neuromuscular Centre, University of Oxford, United Kingdom
| | - Caleb Webber
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,UK Dementia Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,School of Medicine, Keele University, Staffordshire, United Kingdom.,Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom
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47
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Abstract
The majority of the mammalian genome is transcribed into non-coding RNAs, many of which co-evolve with RNA-binding proteins (RBPs) to function as biochemically defined and tractable ribonucleoproteins (RNPs). Here, we applied icSHAPE- a robust and versatile RNA structural probing pipeline- to endogenous RNPs purified from nuclei, providing base-resolution structural rationale for RNP activity and subcellular localization. Combining with genetic and biochemical reconstitutions, structural and functional alternations can be directly attributed to a given RBP without ambiguity. For complete details on the use and execution of this protocol, please refer to Chen et al. (2018).
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Affiliation(s)
- Lu Chen
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Howard Y. Chang
- Center for Personal Dynamic Regulomes, Stanford University, Stanford, CA 94305, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Steven E. Artandi
- Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
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48
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Xu XC, He S, Zhou YQ, Liu CJ, Liu SQ, Peng W, Liu YX, Wei PP, Bei JX, Luo CL. RNA-binding motif protein RBM47 promotes tumorigenesis in nasopharyngeal carcinoma through multiple pathways. J Genet Genomics 2021; 48:595-605. [PMID: 34274258 DOI: 10.1016/j.jgg.2021.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 12/13/2022]
Abstract
RNA binding motif proteins (RBMs) have been widely implicated in the tumorigenesis of multiple human cancers but scarcely studied in nasopharyngeal carcinoma (NPC). Here, we compare the mRNA levels of 29 RBMs between 87 NPC and 10 control samples. We find that RBM47 is frequently upregulated in NPC specimens, and its high expression is associated with the poor prognosis of patients with NPC. Biological experiments show that RBM47 plays an oncogenic role in NPC cells. Mechanically, RBM47 binds to the promoter and regulates the transcription of BCAT1, and its overexpression partially rescues the inhibitory effects of RBM47-knockdown on NPC cells. Moreover, transcriptome analysis reveals that RBM47 regulates alternative splicing of pre-mRNA, including those cancer-related, to a large extent in NPC cells. Furthermore, RBM47 binds to hnRNPM and cooperatively regulates multiple splicing events in NPC cells. In addition, we find that knockdown of hnRNPM inhibits proliferation and migration of NPC cells. Our study, taken together, shows that RBM47 promotes the progression of NPC through multiple pathways, acting as a transcriptional factor and a modulator of alternative splicing in cooperation with hnRNPM. Our study also highlights that RBM47 and hnRNPM could be prognostic factors and potential therapeutic targets for NPC.
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Affiliation(s)
- Xiao-Chen Xu
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Shuai He
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Ya-Qing Zhou
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Chu-Jun Liu
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Shu-Qiang Liu
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Wan Peng
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Yu-Xiang Liu
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Pan-Pan Wei
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China
| | - Jin-Xin Bei
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China; Department of Experimental Research, Sun Yat-sen University Cancer Center, Guangzhou 510060, PR China; Department of Medical Oncology, National Cancer Centre of Singapore, Singapore
| | - Chun-Ling Luo
- Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangzhou 510060, PR China.
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49
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Minor Intron Splicing from Basic Science to Disease. Int J Mol Sci 2021; 22:ijms22116062. [PMID: 34199764 PMCID: PMC8199999 DOI: 10.3390/ijms22116062] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 01/14/2023] Open
Abstract
Pre-mRNA splicing is an essential step in gene expression and is catalyzed by two machineries in eukaryotes: the major (U2 type) and minor (U12 type) spliceosomes. While the majority of introns in humans are U2 type, less than 0.4% are U12 type, also known as minor introns (mi-INTs), and require a specialized spliceosome composed of U11, U12, U4atac, U5, and U6atac snRNPs. The high evolutionary conservation and apparent splicing inefficiency of U12 introns have set them apart from their major counterparts and led to speculations on the purpose for their existence. However, recent studies challenged the simple concept of mi-INTs splicing inefficiency due to low abundance of their spliceosome and confirmed their regulatory role in alternative splicing, significantly impacting the expression of their host genes. Additionally, a growing list of minor spliceosome-associated diseases with tissue-specific pathologies affirmed the importance of minor splicing as a key regulatory pathway, which when deregulated could lead to tissue-specific pathologies due to specific alterations in the expression of some minor-intron-containing genes. Consequently, uncovering how mi-INTs splicing is regulated in a tissue-specific manner would allow for better understanding of disease pathogenesis and pave the way for novel therapies, which we highlight in this review.
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50
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Kobayashi M, Zochodne DW. Diabetic polyneuropathy: Bridging the translational gap. J Peripher Nerv Syst 2021; 25:66-75. [PMID: 32573914 DOI: 10.1111/jns.12392] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 12/22/2022]
Abstract
Clinical trials for diabetic polyneuropathy (DPN) have failed to identify therapeutic impacts that have arrested or reversed the disorder, despite a long history. This review considers DPN in the context of a unique neurodegenerative disorder that targets peripheral neurons and their companion glial cells. The approach is to examine what cells, cell substructures, and pathways are implicated in causing DPN and how they might be addressed therapeutically. These include axonopathy, neuronopathy, hyperglycemia, polyol flux, advanced glycation endproduct (AGE)-receptor AGE signaling, growth factor disruption, abnormal insulin signaling, and abnormalities of other intrinsic neuron pathways. Mitochondrial dysfunction and lipid toxicity are largely delegated to the companion review in this issue by Stino and Feldman. Finally, the linkage between axon plasticity of cutaneous nerves, peripheral neuroregenerative pathways, and diabetes are discussed.
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Affiliation(s)
- Masaki Kobayashi
- Department of Neurology, Nissan Tamagawa Hospital, Tokyo, Japan.,Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Douglas W Zochodne
- Division of Neurology and Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Alberta, Canada
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