1
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Garcia EL, Steiner RE, Raimer AC, Herring LE, Matera AG, Spring AM. Dysregulation of innate immune signaling in animal models of spinal muscular atrophy. BMC Biol 2024; 22:94. [PMID: 38664795 PMCID: PMC11044505 DOI: 10.1186/s12915-024-01888-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is a devastating neuromuscular disease caused by hypomorphic loss of function in the survival motor neuron (SMN) protein. SMA presents across a broad spectrum of disease severity. Unfortunately, genetic models of intermediate SMA have been difficult to generate in vertebrates and are thus unable to address key aspects of disease etiology. To address these issues, we developed a Drosophila model system that recapitulates the full range of SMA severity, allowing studies of pre-onset biology as well as late-stage disease processes. RESULTS Here, we carried out transcriptomic and proteomic profiling of mild and intermediate Drosophila models of SMA to elucidate molecules and pathways that contribute to the disease. Using this approach, we elaborated a role for the SMN complex in the regulation of innate immune signaling. We find that mutation or tissue-specific depletion of SMN induces hyperactivation of the immune deficiency (IMD) and Toll pathways, leading to overexpression of antimicrobial peptides (AMPs) and ectopic formation of melanotic masses in the absence of an external challenge. Furthermore, the knockdown of downstream targets of these signaling pathways reduced melanotic mass formation caused by SMN loss. Importantly, we identify SMN as a negative regulator of a ubiquitylation complex that includes Traf6, Bendless, and Diap2 and plays a pivotal role in several signaling networks. CONCLUSIONS In alignment with recent research on other neurodegenerative diseases, these findings suggest that hyperactivation of innate immunity contributes to SMA pathology. This work not only provides compelling evidence that hyperactive innate immune signaling is a primary effect of SMN depletion, but it also suggests that the SMN complex plays a regulatory role in this process in vivo. In summary, immune dysfunction in SMA is a consequence of reduced SMN levels and is driven by cellular and molecular mechanisms that are conserved between insects and mammals.
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Affiliation(s)
- Eric L Garcia
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Department of Biology, University of Kentucky, Lexington, KY, USA
| | - Rebecca E Steiner
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- RNA Discovery and Lineberger Comprehensive Cancer Centers, University of North Carolina at Chapel Hill, Chapel Hill, 27599, USA
- Present Address: Lake, Erie College of Osteopathic Medicine, Bradenton, FL, USA
| | - Amanda C Raimer
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, 27599, USA
- Present Address, Radford University, Radford, VA, USA
| | - Laura E Herring
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - A Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, 27599, USA.
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, 27599, USA.
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, 27599, USA.
- RNA Discovery and Lineberger Comprehensive Cancer Centers, University of North Carolina at Chapel Hill, Chapel Hill, 27599, USA.
| | - Ashlyn M Spring
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, 27402, USA.
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2
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Westover KR, Jin P, Yao B. Bridging the gap: R-loop mediated genomic instability and its implications in neurological diseases. Epigenomics 2024; 16:589-608. [PMID: 38530068 PMCID: PMC11160457 DOI: 10.2217/epi-2023-0379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 03/12/2024] [Indexed: 03/27/2024] Open
Abstract
R-loops, intricate three-stranded structures formed by RNA-DNA hybrids and an exposed non-template DNA strand, are fundamental to various biological phenomena. They carry out essential and contrasting functions within cellular mechanisms, underlining their critical role in maintaining cellular homeostasis. The specific cellular context that dictates R-loop formation determines their function, particularly emphasizing the necessity for their meticulous genomic regulation. Notably, the aberrant formation or misregulation of R-loops is implicated in numerous neurological disorders. This review focuses on the complex interactions between R-loops and double-strand DNA breaks, exploring how R-loop dysregulation potentially contributes to the pathogenesis of various brain disorders, which could provide novel insights into the molecular mechanisms underpinning neurological disease progression and identify potential therapeutic targets by highlighting these aspects.
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Affiliation(s)
- Katherine R Westover
- Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA 30322, USA
| | - Peng Jin
- Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA 30322, USA
| | - Bing Yao
- Department of Human Genetics, Emory University, School of Medicine, Atlanta, GA 30322, USA
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3
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Garcia EL, Steiner RE, Raimer AC, Herring LE, Matera AG, Spring AM. Dysregulation of innate immune signaling in animal models of Spinal Muscular Atrophy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.14.571739. [PMID: 38168196 PMCID: PMC10760185 DOI: 10.1101/2023.12.14.571739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Background Spinal Muscular Atrophy (SMA) is a devastating neuromuscular disease caused by hypomorphic loss of function in the Survival Motor Neuron (SMN) protein. SMA presents across broad spectrum of disease severity. Unfortunately, vertebrate models of intermediate SMA have been difficult to generate and are thus unable to address key aspects of disease etiology. To address these issues, we developed a Drosophila model system that recapitulates the full range of SMA severity, allowing studies of pre-onset biology as well as late-stage disease processes. Results Here, we carried out transcriptomic and proteomic profiling of mild and intermediate Drosophila models of SMA to elucidate molecules and pathways that contribute to the disease. Using this approach, we elaborated a role for the SMN complex in the regulation of innate immune signaling. We find that mutation or tissue-specific depletion of SMN induces hyperactivation of the Immune Deficiency (IMD) and Toll pathways, leading to overexpression of antimicrobial peptides (AMPs) and ectopic formation of melanotic masses in the absence of an external challenge. Furthermore, knockdown of downstream targets of these signaling pathways reduced melanotic mass formation caused by SMN loss. Importantly, we identify SMN as a negative regulator of an ubiquitylation complex that includes Traf6, Bendless and Diap2, and plays a pivotal role in several signaling networks. Conclusions In alignment with recent research on other neurodegenerative diseases, these findings suggest that hyperactivation of innate immunity contributes to SMA pathology. This work not only provides compelling evidence that hyperactive innate immune signaling is a primary effect of SMN depletion, but it also suggests that the SMN complex plays a regulatory role in this process in vivo. In summary, immune dysfunction in SMA is a consequence of reduced SMN levels and is driven by cellular and molecular mechanisms that are conserved between insects and mammals.
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Affiliation(s)
- Eric L. Garcia
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill NC, USA
- Department of Biology, University of Kentucky, Lexington KY, USA
| | - Rebecca E. Steiner
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill NC, USA
- Department of Biology, University of North Carolina at Chapel Hill
| | - Amanda C. Raimer
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill
| | - Laura E. Herring
- Department of Pharmacology, University of North Carolina at Chapel Hill
| | - A. Gregory Matera
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill NC, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill
- Department of Biology, University of North Carolina at Chapel Hill
- Department of Genetics, University of North Carolina at Chapel Hill
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill
| | - Ashlyn M. Spring
- Integrative Program for Biological and Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill NC, USA
- Department of Biology, University of North Carolina at Greensboro, Greensboro NC, USA
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4
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He L, Xie Y, Qiu Y, Zhang Y. Pan-Cancer Profiling and Digital Pathology Analysis Reveal Negative Prognostic Biomarker ZPR1 Associated with Immune Infiltration and Treatment Response in Hepatocellular Carcinoma. J Hepatocell Carcinoma 2023; 10:1309-1325. [PMID: 37581094 PMCID: PMC10423584 DOI: 10.2147/jhc.s415224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 07/20/2023] [Indexed: 08/16/2023] Open
Abstract
Purpose ZPR1 is a zinc finger-containing protein that plays a crucial role in neurodegenerative diseases, lipid metabolism disorders, and non-alcoholic fatty liver disease. However, the expression pattern, prognostic value, and treatment response of ZPR1 in pan-cancer and hepatocellular carcinoma (HCC) remain unclear. Patients and Methods Pan-cancer expression profiles and relevant clinical data were acquired from UCSC Xena platform. Pan-cancer expression, epigenetic profile, and clinical correlation analysis for ZPR1 were performed. We next explored the prognostic significance and potential biological functions of ZPR1 in HCC. Furthermore, the relationship between ZPR1 and immune infiltration and treatment response was investigated. Finally, quantitative immunohistochemistry (IHC) analysis was applied to assess the correlation of ZPR1 expression and immune microenvironment in HCC tissues using Qupath software. Results ZPR1 was differentially expressed in most tumor types and significantly up-regulated in HCC. ZPR1 showed hypo-methylated status in most tumors. Pan-cancer correlation analysis indicated that ZPR1 was closely associated with clinicopathological factors and TMB, MSI, and stemness index in HCC. High ZPR1 expression could be an independent risk factor for adverse prognosis in HCC. ZPR1 correlated with immune cell infiltration and therapeutic response. Finally, IHC results suggested that ZPR1 correlated with CD4, CD56, CD68, and PD-L1 expression and is a promising pathological diagnostic marker in HCC. Conclusion Immune infiltrate-associated ZPR1 could be considered a novel negative prognostic biomarker for therapeutic response in HCC.
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Affiliation(s)
- Lian He
- Department of Pathology, Cancer Hospital of Dalian University of Technology (Liaoning Cancer Hospital & Institute), Shenyang, Liaoning, 110042, People’s Republic of China
| | - Yusai Xie
- Laboratory of Basic Medicine, General Hospital of Northern Theatre Command, Shenyang, Liaoning, 110016, People’s Republic of China
| | - Yusong Qiu
- Department of Pathology, Cancer Hospital of Dalian University of Technology (Liaoning Cancer Hospital & Institute), Shenyang, Liaoning, 110042, People’s Republic of China
| | - Yong Zhang
- Department of Pathology, Cancer Hospital of Dalian University of Technology (Liaoning Cancer Hospital & Institute), Shenyang, Liaoning, 110042, People’s Republic of China
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5
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Ouyang X, Wang X, Li P, Huang Q, Zhou L, Li J, Gao L, Sun Q, Chai F, Guo S, Zhou Z, Liu X, Dai L, Cheng W, Ren H. Bacterial effector restricts liquid-liquid phase separation of ZPR1 to antagonize host UPR ER. Cell Rep 2023; 42:112700. [PMID: 37379216 DOI: 10.1016/j.celrep.2023.112700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 04/29/2023] [Accepted: 06/09/2023] [Indexed: 06/30/2023] Open
Abstract
How pathogens manipulate host UPRER to mediate immune evasion is largely unknown. Here, we identify the host zinc finger protein ZPR1 as an interacting partner of the enteropathogenic E. coli (EPEC) effector NleE using proximity-enabled protein crosslinking. We show that ZPR1 assembles via liquid-liquid phase separation (LLPS) in vitro and regulates CHOP-mediated UPRER at the transcriptional level. Interestingly, in vitro studies show that the ZPR1 binding ability with K63-ubiquitin chains, which promotes LLPS of ZPR1, is disrupted by NleE. Further analyses indicate that EPEC restricts host UPRER pathways at the transcription level in a NleE-ZPR1 cascade-dependent manner. Together, our study reveals the mechanism by which EPEC interferes with CHOP-UPRER via regulating ZPR1 to help pathogens escape host defense.
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Affiliation(s)
- Xiaoxiao Ouyang
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Xueyun Wang
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Pan Li
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Qin Huang
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Li Zhou
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Jingxiang Li
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Li Gao
- Department of General Practice and National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, and Sichuan University, Chengdu 610041, China
| | - Qi Sun
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Fangni Chai
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Shupan Guo
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Zhihui Zhou
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Xin Liu
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
| | - Lunzhi Dai
- Department of General Practice and National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, and Sichuan University, Chengdu 610041, China
| | - Wei Cheng
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China; Collaborative Innovation Center of Biotherapy, Sichuan University West China Hospital, Chengdu, Sichuan 610041, China
| | - Haiyan Ren
- Department of Pulmonary and Critical Care, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China; Collaborative Innovation Center of Biotherapy, Sichuan University West China Hospital, Chengdu, Sichuan 610041, China.
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6
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Sabbarini IM, Reif D, McQuown AJ, Nelliat AR, Prince J, Membreno BS, Wu CCC, Murray AW, Denic V. Zinc-finger protein Zpr1 is a bespoke chaperone essential for eEF1A biogenesis. Mol Cell 2023; 83:252-265.e13. [PMID: 36630955 PMCID: PMC10016025 DOI: 10.1016/j.molcel.2022.12.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/15/2022] [Accepted: 12/12/2022] [Indexed: 01/12/2023]
Abstract
The conserved regulon of heat shock factor 1 in budding yeast contains chaperones for general protein folding as well as zinc-finger protein Zpr1, whose essential role in archaea and eukaryotes remains unknown. Here, we show that Zpr1 depletion causes acute proteotoxicity driven by biosynthesis of misfolded eukaryotic translation elongation factor 1A (eEF1A). Prolonged Zpr1 depletion leads to eEF1A insufficiency, thereby inducing the integrated stress response and inhibiting protein synthesis. Strikingly, we show by using two distinct biochemical reconstitution approaches that Zpr1 enables eEF1A to achieve a conformational state resistant to protease digestion. Lastly, we use a ColabFold model of the Zpr1-eEF1A complex to reveal a folding mechanism mediated by the Zpr1's zinc-finger and alpha-helical hairpin structures. Our work uncovers the long-sought-after function of Zpr1 as a bespoke chaperone tailored to the biogenesis of one of the most abundant proteins in the cell.
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Affiliation(s)
- Ibrahim M Sabbarini
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Dvir Reif
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Alexander J McQuown
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Anjali R Nelliat
- Graduate Program in Systems Biology, Harvard Medical School, Boston, MA 02115, USA
| | - Jeffrey Prince
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Britnie Santiago Membreno
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Colin Chih-Chien Wu
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Andrew W Murray
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
| | - Vladimir Denic
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
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7
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Adami R, Bottai D. NSC Physiological Features in Spinal Muscular Atrophy: SMN Deficiency Effects on Neurogenesis. Int J Mol Sci 2022; 23:ijms232315209. [PMID: 36499528 PMCID: PMC9736802 DOI: 10.3390/ijms232315209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 11/20/2022] [Accepted: 11/30/2022] [Indexed: 12/08/2022] Open
Abstract
While the U.S. Food and Drug Administration and the European Medicines Evaluation Agency have recently approved new drugs to treat spinal muscular atrophy 1 (SMA1) in young patients, they are mostly ineffective in older patients since many motor neurons have already been lost. Therefore, understanding nervous system (NS) physiology in SMA patients is essential. Consequently, studying neural stem cells (NSCs) from SMA patients is of significant interest in searching for new treatment targets that will enable researchers to identify new pharmacological approaches. However, studying NSCs in these patients is challenging since their isolation damages the NS, making it impossible with living patients. Nevertheless, it is possible to study NSCs from animal models or create them by differentiating induced pluripotent stem cells obtained from SMA patient peripheral tissues. On the other hand, therapeutic interventions such as NSCs transplantation could ameliorate SMA condition. This review summarizes current knowledge on the physiological properties of NSCs from animals and human cellular models with an SMA background converging on the molecular and neuronal circuit formation alterations of SMA fetuses and is not focused on the treatment of SMA. By understanding how SMA alters NSC physiology, we can identify new and promising interventions that could help support affected patients.
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8
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Cuartas J, Gangwani L. Zinc finger protein ZPR1: promising survival motor neuron protein-dependent modifier for the rescue of spinal muscular atrophy. Neural Regen Res 2022; 17:2225-2227. [PMID: 35259840 PMCID: PMC9083177 DOI: 10.4103/1673-5374.335798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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, USA
| | - 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, USA
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9
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Zhuri D, Gurkan H, Eker D, Karal Y, Yalcintepe S, Atli E, Demir S, Atli EI. Investigation on the Effects of Modifying Genes on the Spinal Muscular Atrophy Phenotype. Glob Med Genet 2022; 9:226-236. [PMID: 36071912 PMCID: PMC9444347 DOI: 10.1055/s-0042-1751302] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Introduction
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder caused by the degeneration of motor neurons, muscle weakness, and atrophy that leads to infant's death. The duplication of exon 7/8 in the
SMN2
gene reduces the clinical severity of disease, and it is defined as modifying effect. In this study, we aim to investigate the expression of modifying genes related to the prognosis of SMA like
PLS3
,
PFN2
,
ZPR1
,
CORO1C
,
GTF2H2
,
NRN1
,
SERF1A
,
NCALD
,
NAIP
, and
TIA1. Methods
Seventeen patients, who came to Trakya University, Faculty of Medicine, Medical Genetics Department, with a preliminary diagnosis of SMA disease, and eight healthy controls were included in this study after multiplex ligation-dependent probe amplification analysis. Gene expression levels were determined by real-time reverse transcription polymerase chain reaction and delta–delta CT method by the isolation of RNA from peripheral blood of patients and controls.
Results
SERF1A
and
NAIP
genes compared between A group and B + C + D groups, and A group of healthy controls, showed statistically significant differences (
p
= 0.037,
p
= 0.001).
Discussion
PLS3, NAIP
, and
NRN1
gene expressions related to SMA disease have been reported before in the literature. In our study, the expression levels of
SERF1A
,
GTF2H2
,
NCALD
,
ZPR1
,
TIA1
,
PFN2
, and
CORO1C
genes have been studied for the first time in SMA patients.
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Affiliation(s)
- Drenushe Zhuri
- Department of Medical Genetics, Trakya University Faculty of Medicine, Edirne, Turkey
| | - Hakan Gurkan
- Department of Medical Genetics, Trakya University Faculty of Medicine, Edirne, Turkey
| | - Damla Eker
- Department of Medical Genetics, Trakya University Faculty of Medicine, Edirne, Turkey
| | - Yasemin Karal
- Department of Pediatric Neurology, Trakya University Faculty of Medicine, Edirne, Turkey
| | - Sinem Yalcintepe
- Department of Medical Genetics, Trakya University Faculty of Medicine, Edirne, Turkey
| | - Engin Atli
- Department of Medical Genetics, Trakya University Faculty of Medicine, Edirne, Turkey
| | - Selma Demir
- Department of Medical Genetics, Trakya University Faculty of Medicine, Edirne, Turkey
| | - Emine Ikbal Atli
- Department of Medical Genetics, Trakya University Faculty of Medicine, Edirne, Turkey
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10
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Detering NT, Schüning T, Hensel N, Claus P. The phospho-landscape of the survival of motoneuron protein (SMN) protein: relevance for spinal muscular atrophy (SMA). Cell Mol Life Sci 2022; 79:497. [PMID: 36006469 PMCID: PMC11071818 DOI: 10.1007/s00018-022-04522-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 07/27/2022] [Accepted: 08/09/2022] [Indexed: 11/03/2022]
Abstract
Spinal muscular atrophy (SMA) is caused by low levels of the survival of motoneuron (SMN) Protein leading to preferential degeneration of lower motoneurons in the ventral horn of the spinal cord and brain stem. However, the SMN protein is ubiquitously expressed and there is growing evidence of a multisystem phenotype in SMA. Since a loss of SMN function is critical, it is important to decipher the regulatory mechanisms of SMN function starting on the level of the SMN protein itself. Posttranslational modifications (PTMs) of proteins regulate multiple functions and processes, including activity, cellular trafficking, and stability. Several PTM sites have been identified within the SMN sequence. Here, we map the identified SMN PTMs highlighting phosphorylation as a key regulator affecting localization, stability and functions of SMN. Furthermore, we propose SMN phosphorylation as a crucial factor for intracellular interaction and cellular distribution of SMN. We outline the relevance of phosphorylation of the spinal muscular atrophy (SMA) gene product SMN with regard to basic housekeeping functions of SMN impaired in this neurodegenerative disease. Finally, we compare SMA patient mutations with putative and verified phosphorylation sites. Thus, we emphasize the importance of phosphorylation as a cellular modulator in a clinical perspective as a potential additional target for combinatorial SMA treatment strategies.
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Affiliation(s)
- Nora Tula Detering
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Tobias Schüning
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Niko Hensel
- Ottawa Hospital Research Institute (OHRI), Ottawa, Canada
- Center for Systems Neuroscience (ZSN), Hannover, Germany
| | - Peter Claus
- SMATHERIA gGmbH - Non-Profit Biomedical Research Institute, Hannover, Germany.
- Center for Systems Neuroscience (ZSN), Hannover, Germany.
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11
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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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12
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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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13
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Hensel N, Brickwedde H, Tsaknakis K, Grages A, Braunschweig L, Lüders KA, Lorenz HM, Lippross S, Walter LM, Tavassol F, Lienenklaus S, Neunaber C, Claus P, Hell AK. Altered bone development with impaired cartilage formation precedes neuromuscular symptoms in spinal muscular atrophy. Hum Mol Genet 2021; 29:2662-2673. [PMID: 32644125 DOI: 10.1093/hmg/ddaa145] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/06/2020] [Accepted: 07/06/2020] [Indexed: 01/04/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a fatal neurodegenerative disease of newborns and children caused by mutations or deletions of the survival of motoneuron gene 1 resulting in low levels of the SMN protein. While neuromuscular degeneration is the cardinal symptom of the disease, the reduction of the ubiquitously expressed SMN additionally elicits non-motoneuron symptoms. Impaired bone development is a key feature of SMA, but it is yet unknown whether this is an indirect functional consequence of muscle weakness or caused by bone-intrinsic mechanisms. Therefore, we radiologically examined SMA patients in a prospective, non-randomized cohort study characterizing bone size and bone mineral density (BMD) and performed equivalent measurements in pre-symptomatic SMA mice. BMD as well as lumbar vertebral body size were significantly reduced in SMA patients. This growth defect but not BMD reduction was confirmed in SMA mice by μCT before the onset of neuromuscular symptoms indicating that it is at least partially independent of neuromuscular degeneration. Interestingly, the number of chondroblasts in the hypertrophic zone of the growth plate was significantly reduced. This was underlined by RNAseq and expression data from developing SMA mice vertebral bodies, which revealed molecular changes related to cell division and cartilage remodeling. Together, these findings suggest a bone intrinsic defect in SMA. This phenotype may not be rescued by novel drugs that enhance SMN levels in the central nervous system only.
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Affiliation(s)
- Niko Hensel
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Hermann Brickwedde
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany
| | - Konstantinos Tsaknakis
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Antonia Grages
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Lena Braunschweig
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Katja A Lüders
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Heiko M Lorenz
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Sebastian Lippross
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
| | - Lisa M Walter
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Frank Tavassol
- Department of Oral and Maxillofacial Surgery, Hannover Medical School, Hannover, Germany
| | - Stefan Lienenklaus
- Institute for Laboratory Animal Science and Central Animal Facility, Hannover Medical School, Hannover, Germany
| | | | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany.,Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Anna K Hell
- Pediatric Orthopedics, Department of Trauma, Orthopedic and Plastic Surgery, University Medical Center Goettingen, Goettingen, Germany
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14
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Chong LC, Gandhi G, Lee JM, Yeo WWY, Choi SB. Drug Discovery of Spinal Muscular Atrophy (SMA) from the Computational Perspective: A Comprehensive Review. Int J Mol Sci 2021; 22:8962. [PMID: 34445667 PMCID: PMC8396480 DOI: 10.3390/ijms22168962] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 01/27/2021] [Indexed: 01/02/2023] Open
Abstract
Spinal muscular atrophy (SMA), one of the leading inherited causes of child mortality, is a rare neuromuscular disease arising from loss-of-function mutations of the survival motor neuron 1 (SMN1) gene, which encodes the SMN protein. When lacking the SMN protein in neurons, patients suffer from muscle weakness and atrophy, and in the severe cases, respiratory failure and death. Several therapeutic approaches show promise with human testing and three medications have been approved by the U.S. Food and Drug Administration (FDA) to date. Despite the shown promise of these approved therapies, there are some crucial limitations, one of the most important being the cost. The FDA-approved drugs are high-priced and are shortlisted among the most expensive treatments in the world. The price is still far beyond affordable and may serve as a burden for patients. The blooming of the biomedical data and advancement of computational approaches have opened new possibilities for SMA therapeutic development. This article highlights the present status of computationally aided approaches, including in silico drug repurposing, network driven drug discovery as well as artificial intelligence (AI)-assisted drug discovery, and discusses the future prospects.
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Affiliation(s)
- Li Chuin Chong
- Centre for Bioinformatics, School of Data Sciences, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (L.C.C.); (J.M.L.)
| | - Gayatri Gandhi
- Perdana University Graduate School of Medicine, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (G.G.); (W.W.Y.Y.)
| | - Jian Ming Lee
- Centre for Bioinformatics, School of Data Sciences, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (L.C.C.); (J.M.L.)
| | - Wendy Wai Yeng Yeo
- Perdana University Graduate School of Medicine, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (G.G.); (W.W.Y.Y.)
| | - Sy-Bing Choi
- Centre for Bioinformatics, School of Data Sciences, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (L.C.C.); (J.M.L.)
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15
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Mills A, Gago F. On the Need to Tell Apart Fraternal Twins eEF1A1 and eEF1A2, and Their Respective Outfits. Int J Mol Sci 2021; 22:6973. [PMID: 34203525 PMCID: PMC8268798 DOI: 10.3390/ijms22136973] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/25/2021] [Accepted: 06/25/2021] [Indexed: 01/03/2023] Open
Abstract
eEF1A1 and eEF1A2 are paralogous proteins whose presence in most normal eukaryotic cells is mutually exclusive and developmentally regulated. Often described in the scientific literature under the collective name eEF1A, which stands for eukaryotic elongation factor 1A, their best known activity (in a monomeric, GTP-bound conformation) is to bind aminoacyl-tRNAs and deliver them to the A-site of the 80S ribosome. However, both eEF1A1 and eEF1A2 are endowed with multitasking abilities (sometimes performed by homo- and heterodimers) and can be located in different subcellular compartments, from the plasma membrane to the nucleus. Given the high sequence identity of these two sister proteins and the large number of post-translational modifications they can undergo, we are often confronted with the dilemma of discerning which is the particular proteoform that is actually responsible for the ascribed biochemical or cellular effects. We argue in this review that acquiring this knowledge is essential to help clarify, in molecular and structural terms, the mechanistic involvement of these two ancestral and abundant G proteins in a variety of fundamental cellular processes other than translation elongation. Of particular importance for this special issue is the fact that several de novo heterozygous missense mutations in the human EEF1A2 gene are associated with a subset of rare but severe neurological syndromes and cardiomyopathies.
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Affiliation(s)
| | - Federico Gago
- Department of Biomedical Sciences & “Unidad Asociada IQM-CSIC”, School of Medicine and Health Sciences, University of Alcalá, E-28805 Alcalá de Henares, Spain;
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16
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James R, Chaytow H, Ledahawsky LM, Gillingwater TH. Revisiting the role of mitochondria in spinal muscular atrophy. Cell Mol Life Sci 2021; 78:4785-4804. [PMID: 33821292 PMCID: PMC8195803 DOI: 10.1007/s00018-021-03819-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 02/22/2021] [Accepted: 03/23/2021] [Indexed: 02/07/2023]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease of variable clinical severity that is caused by mutations in the survival motor neuron 1 (SMN1) gene. Despite its name, SMN is a ubiquitous protein that functions within and outside the nervous system and has multiple cellular roles in transcription, translation, and proteostatic mechanisms. Encouragingly, several SMN-directed therapies have recently reached the clinic, albeit this has highlighted the increasing need to develop combinatorial therapies for SMA to achieve full clinical efficacy. As a subcellular site of dysfunction in SMA, mitochondria represents a relevant target for a combinatorial therapy. Accordingly, we will discuss our current understanding of mitochondrial dysfunction in SMA, highlighting mitochondrial-based pathways that offer further mechanistic insights into the involvement of mitochondria in SMA. This may ultimately facilitate translational development of targeted mitochondrial therapies for SMA. Due to clinical and mechanistic overlaps, such strategies may also benefit other motor neuron diseases and related neurodegenerative disorders.
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Affiliation(s)
- Rachel James
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Helena Chaytow
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Leire M Ledahawsky
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
| | - Thomas H Gillingwater
- Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK.
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK.
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17
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Rademacher S, Detering NT, Schüning T, Lindner R, Santonicola P, Wefel IM, Dehus J, Walter LM, Brinkmann H, Niewienda A, Janek K, Varela MA, Bowerman M, Di Schiavi E, Claus P. A Single Amino Acid Residue Regulates PTEN-Binding and Stability of the Spinal Muscular Atrophy Protein SMN. Cells 2020; 9:cells9112405. [PMID: 33153033 PMCID: PMC7692393 DOI: 10.3390/cells9112405] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 10/23/2020] [Accepted: 10/27/2020] [Indexed: 11/16/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a neuromuscular disease caused by decreased levels of the survival of motoneuron (SMN) protein. Post-translational mechanisms for regulation of its stability are still elusive. Thus, we aimed to identify regulatory phosphorylation sites that modulate function and stability. Our results show that SMN residues S290 and S292 are phosphorylated, of which SMN pS290 has a detrimental effect on protein stability and nuclear localization. Furthermore, we propose that phosphatase and tensin homolog (PTEN), a novel phosphatase for SMN, counteracts this effect. In light of recent advancements in SMA therapies, a significant need for additional approaches has become apparent. Our study demonstrates S290 as a novel molecular target site to increase the stability of SMN. Characterization of relevant kinases and phosphatases provides not only a new understanding of SMN function, but also constitutes a novel strategy for combinatorial therapeutic approaches to increase the level of SMN in SMA.
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Affiliation(s)
- Sebastian Rademacher
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany; (S.R.); (N.T.D.); (T.S.); (R.L.); (I.-M.W.); (J.D.); (L.M.W.); (H.B.)
| | - Nora T. Detering
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany; (S.R.); (N.T.D.); (T.S.); (R.L.); (I.-M.W.); (J.D.); (L.M.W.); (H.B.)
- Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
| | - Tobias Schüning
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany; (S.R.); (N.T.D.); (T.S.); (R.L.); (I.-M.W.); (J.D.); (L.M.W.); (H.B.)
- Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
| | - Robert Lindner
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany; (S.R.); (N.T.D.); (T.S.); (R.L.); (I.-M.W.); (J.D.); (L.M.W.); (H.B.)
| | - Pamela Santonicola
- Institute of Biosciences and Bioresources, National Research Council of Italy, 80131 Naples, Italy; (P.S.); (E.D.S.)
| | - Inga-Maria Wefel
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany; (S.R.); (N.T.D.); (T.S.); (R.L.); (I.-M.W.); (J.D.); (L.M.W.); (H.B.)
| | - Janina Dehus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany; (S.R.); (N.T.D.); (T.S.); (R.L.); (I.-M.W.); (J.D.); (L.M.W.); (H.B.)
| | - Lisa M. Walter
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany; (S.R.); (N.T.D.); (T.S.); (R.L.); (I.-M.W.); (J.D.); (L.M.W.); (H.B.)
- Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
| | - Hella Brinkmann
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany; (S.R.); (N.T.D.); (T.S.); (R.L.); (I.-M.W.); (J.D.); (L.M.W.); (H.B.)
| | - Agathe Niewienda
- Shared Facility for Mass Spectrometry, Institute of Biochemistry, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (A.N.); (K.J.)
| | - Katharina Janek
- Shared Facility for Mass Spectrometry, Institute of Biochemistry, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (A.N.); (K.J.)
| | - Miguel A. Varela
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK; (M.A.V.); (M.B.)
- Department of Paediatrics, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DU, UK
| | - Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK; (M.A.V.); (M.B.)
- School of Medicine, Keele University, Staffordshire ST5 5BG, UK
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10 7AG, UK
| | - Elia Di Schiavi
- Institute of Biosciences and Bioresources, National Research Council of Italy, 80131 Naples, Italy; (P.S.); (E.D.S.)
| | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany; (S.R.); (N.T.D.); (T.S.); (R.L.); (I.-M.W.); (J.D.); (L.M.W.); (H.B.)
- Center for Systems Neuroscience (ZSN), 30559 Hannover, Germany
- Correspondence:
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18
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Kannan A, Jiang X, He L, Ahmad S, Gangwani L. ZPR1 prevents R-loop accumulation, upregulates SMN2 expression and rescues spinal muscular atrophy. Brain 2020; 143:69-93. [PMID: 31828288 PMCID: PMC6935747 DOI: 10.1093/brain/awz373] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 09/08/2019] [Accepted: 10/07/2019] [Indexed: 12/21/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder caused by homozygous mutation or deletion of the survival motor neuron 1 (SMN1) gene. A second copy, SMN2, is similar to SMN1 but produces ∼10% SMN protein because of a single-point mutation that causes splicing defects. Chronic low levels of SMN cause accumulation of co-transcriptional R-loops and DNA damage leading to genomic instability and neurodegeneration in SMA. Severity of SMA disease correlates inversely with SMN levels. SMN2 is a promising target to produce higher levels of SMN by enhancing its expression. Mechanisms that regulate expression of SMN genes are largely unknown. We report that zinc finger protein ZPR1 binds to RNA polymerase II, interacts in vivo with SMN locus and upregulates SMN2 expression in SMA mice and patient cells. Modulation of ZPR1 levels directly correlates and influences SMN2 expression levels in SMA patient cells. ZPR1 overexpression in vivo results in a systemic increase of SMN levels and rescues severe to moderate disease in SMA mice. ZPR1-dependent rescue improves growth and motor function and increases the lifespan of male and female SMA mice. ZPR1 reduces neurodegeneration in SMA mice and prevents degeneration of cultured primary spinal cord neurons derived from SMA mice. Further, we show that the low levels of ZPR1 associated with SMA pathogenesis cause accumulation of co-transcriptional RNA-DNA hybrids (R-loops) and DNA damage leading to genomic instability in SMA mice and patient cells. Complementation with ZPR1 elevates senataxin levels, reduces R-loop accumulation and rescues DNA damage in SMA mice, motor neurons and patient cells. In conclusion, ZPR1 is critical for preventing accumulation of co-transcriptional R-loops and DNA damage to avert genomic instability and neurodegeneration in SMA. ZPR1 enhances SMN2 expression and leads to SMN-dependent rescue of SMA. ZPR1 represents a protective modifier and a therapeutic target for developing a new method for the treatment of SMA.
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Affiliation(s)
- Annapoorna Kannan
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA.,Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA
| | - Xiaoting Jiang
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA.,Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA
| | - Lan He
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA.,Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA
| | - Saif Ahmad
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA.,Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA.,Department of Molecular and Translational Medicine, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA.,Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA
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19
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Lomonte P, Baklouti F, Binda O. The Biochemistry of Survival Motor Neuron Protein Is Paving the Way to Novel Therapies for Spinal Muscle Atrophy. Biochemistry 2020; 59:1391-1397. [PMID: 32227847 DOI: 10.1021/acs.biochem.9b01124] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spinal muscle atrophy (SMA) is the leading genetic cause of infant mortality. SMA originates from the loss of functional survival motor neuron (SMN) protein. In most SMA cases, the SMN1 gene is deleted. However, in some cases, SMN is mutated, impairing its biological functions. SMN mutants could provide clues about the biological functions of SMN and the specific impact on SMA, potentially leading to the identification of new pathways and thus providing novel treatment alternatives, and even personalized care. Here, we discuss the biochemistry of SMN and the most recent SMA treatment strategies.
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Affiliation(s)
- Patrick Lomonte
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène (INMG), 69008 Lyon, France
| | - Faouzi Baklouti
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène (INMG), 69008 Lyon, France
| | - Olivier Binda
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène (INMG), 69008 Lyon, France
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20
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Jiang X, Kannan A, Gangwani L. ZPR1-Dependent Neurodegeneration Is Mediated by the JNK Signaling Pathway. J Exp Neurosci 2019; 13:1179069519867915. [PMID: 31488953 PMCID: PMC6709431 DOI: 10.1177/1179069519867915] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 07/15/2019] [Indexed: 01/16/2023] Open
Abstract
The zinc finger protein ZPR1 deficiency causes neurodegeneration and results in a
mild spinal muscular atrophy (SMA)-like disease in mice with reduced
Zpr1 gene dosage. Mutation of the survival motor
neuron 1 (SMN1) gene causes SMA. Spinal muscular
atrophy is characterized by the degeneration of the spinal cord motor neurons
caused by chronic low levels of SMN protein. ZPR1 interacts with SMN and is
required for nuclear accumulation of SMN. Patients with SMA express reduced
levels of ZPR1. Reduced Zpr1 gene dosage increases
neurodegeneration and severity of SMA disease in mice. Mechanisms underlying
ZPR1-dependent neurodegeneration are largely unknown. We report that
neurodegeneration caused by ZPR1 deficiency is mediated by the c-Jun
NH2-terminal kinase (JNK) group of mitogen-activated protein
kinases (MAPK). ZPR1-dependent neuron degeneration is mediated by central
nervous system (CNS)-specific isoform JNK3. ZPR1 deficiency activates the MAPK
signaling cascade, MLK3 → MKK7 → JNK3, which phosphorylates c-Jun and activates
caspase-mediated neuron degeneration. Neurons from Jnk3-null
mice show resistance to ZPR1-dependent neurodegeneration. Pharmacologic
inhibition of JNK reduces degeneration of ZPR1-deficient neurons. These data
show that ZPR1-dependent neurodegeneration is mediated by the JNK signaling
pathway and suggest that ZPR1 downregulation in SMA may contribute to
JNK-mediated neurodegeneration associated with SMA pathogenesis.
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Affiliation(s)
- Xiaoting Jiang
- 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, USA.,Department of Immunobiology, Houston Methodist Research Institute, Houston, TX, USA
| | - Annapoorna Kannan
- 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, USA
| | - 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, USA.,Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX, USA
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21
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Kannan A, Bhatia K, Branzei D, Gangwani L. Combined deficiency of Senataxin and DNA-PKcs causes DNA damage accumulation and neurodegeneration in spinal muscular atrophy. Nucleic Acids Res 2019; 46:8326-8346. [PMID: 30010942 PMCID: PMC6144794 DOI: 10.1093/nar/gky641] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/05/2018] [Indexed: 12/12/2022] Open
Abstract
Chronic low levels of survival motor neuron (SMN) protein cause spinal muscular atrophy (SMA). SMN is ubiquitously expressed, but the mechanisms underlying predominant neuron degeneration in SMA are poorly understood. We report that chronic low levels of SMN cause Senataxin (SETX)-deficiency, which results in increased RNA–DNA hybrids (R-loops) and DNA double-strand breaks (DSBs), and deficiency of DNA-activated protein kinase-catalytic subunit (DNA-PKcs), which impairs DSB repair. Consequently, DNA damage accumulates in patient cells, SMA mice neurons and patient spinal cord tissues. In dividing cells, DSBs are repaired by homologous recombination (HR) and non-homologous end joining (NHEJ) pathways, but neurons predominantly use NHEJ, which relies on DNA-PKcs activity. In SMA dividing cells, HR repairs DSBs and supports cellular proliferation. In SMA neurons, DNA-PKcs-deficiency causes defects in NHEJ-mediated repair leading to DNA damage accumulation and neurodegeneration. Restoration of SMN levels rescues SETX and DNA-PKcs deficiencies and DSB accumulation in SMA neurons and patient cells. Moreover, SETX overexpression in SMA neurons reduces R-loops and DNA damage, and rescues neurodegeneration. Our findings identify combined deficiency of SETX and DNA-PKcs stemming downstream of SMN as an underlying cause of DSBs accumulation, genomic instability and neurodegeneration in SMA and suggest SETX as a potential therapeutic target for SMA.
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Affiliation(s)
- Annapoorna Kannan
- Center of Emphasis in Neurosciences, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905.,Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905
| | - Kanchan Bhatia
- Center of Emphasis in Neurosciences, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905.,Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905
| | - 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, Pavia 27100, Italy
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences, Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905.,Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905.,Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA
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22
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Qian X, Du Y, Jiang G, Lin F, Yao L. Survival Motor Neuron (SMN) Protein Insufficiency Exacerbates Renal Ischemia/Reperfusion Injury. Front Physiol 2019; 10:559. [PMID: 31139093 PMCID: PMC6527877 DOI: 10.3389/fphys.2019.00559] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/24/2019] [Indexed: 12/14/2022] Open
Abstract
The survival of motor neuron (SMN) protein is ubiquitously involved in spliceosome assembly and ribonucleoprotein biogenesis. SMN protein is expressed in kidney and can affect cell death processes. However, the role of SMN in acute kidney injury (AKI) is largely unknown. In the current study, we found that the expression of SMN in the kidney was significantly reduced in both clinical ischemic AKI and a mouse model of renal ischemia-reperfusion injury (IRI). We then used SMN heterozygous knockout (SMN+/-) mice and found that the declines in renal function, tubular injury, and tubular cell apoptosis after experimental IRI were significantly more severe in SMN+/- mice than those in their wild-type littermates. Concomitantly, the canonical transcription factor nuclear factor-κb (NFκb) signaling was enhanced in ischemic SMN+/- mice. In vitro, cobalt dichloride (CoCl2) treatment reduced SMN expression in proximal tubular epithelial cells. In addition, CoCl2-induced apoptosis and activation of NFκb signaling pathway were enhanced by transient transfection of a small-interfering RNA (siRNA) against SMN while attenuated by transient transfection of a full-length SMN plasmid. Taken together, this study for the first time supported the protective role of SMN in ischemic AKI.
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Affiliation(s)
- Xiaoqian Qian
- Renal Division, Department of Internal Medicine, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Centre for Rare Disease, Shanghai, China
| | - Yichao Du
- Sichuan Provincial Academician (Expert) Workstation, The Affiliated Hospital of Southwest Medical University, Luzhou, China
| | - Gengru Jiang
- Renal Division, Department of Internal Medicine, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Centre for Rare Disease, Shanghai, China
| | - Fujun Lin
- Renal Division, Department of Internal Medicine, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Centre for Rare Disease, Shanghai, China
| | - Lei Yao
- Sichuan Provincial Academician (Expert) Workstation, The Affiliated Hospital of Southwest Medical University, Luzhou, China
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23
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A new biomarker candidate for spinal muscular atrophy: Identification of a peripheral blood cell population capable of monitoring the level of survival motor neuron protein. PLoS One 2018; 13:e0201764. [PMID: 30102724 PMCID: PMC6089418 DOI: 10.1371/journal.pone.0201764] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Accepted: 07/20/2018] [Indexed: 01/01/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a severe genetic neuromuscular disorder caused by insufficiency of functional survival motor neuron (SMN) protein. Several clinical trials have been conducted with the aim of upregulating the expression of the SMN protein in SMA patients. In order to evaluate the efficiency of these SMN-targeted approaches, it has become necessary to verify SMN protein levels in the cells of SMA patients. Accordingly, we have developed a method allowing the evaluation of the functional SMN protein with < 1.5 mL of peripheral blood using imaging flow cytometry. The expression of SMN protein in CD3+, CD19+, and CD33++ cells obtained from SMA patients, was significantly reduced compared with that in cells from control subjects. In spot analysis of CD33++ cells, the intensities of SMN spots were significantly reduced in SMA subjects, when compared with that in controls. Therefore, SMN spots implied the presence of functional SMN protein in the cell nucleus. To our knowledge, our results are the first to demonstrate the presence of functional SMN protein in freshly isolated peripheral blood cells. We anticipate that SMN spot analysis will become the primary endpoint assay for the evaluation and monitoring of therapeutic intervention, with SMN serving as a reliable biomarker of therapeutic efficacy in SMA patients.
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24
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Maretina MA, Zheleznyakova GY, Lanko KM, Egorova AA, Baranov VS, Kiselev AV. Molecular Factors Involved in Spinal Muscular Atrophy Pathways as Possible Disease-modifying Candidates. Curr Genomics 2018; 19:339-355. [PMID: 30065610 PMCID: PMC6030859 DOI: 10.2174/1389202919666180101154916] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Revised: 12/15/2017] [Accepted: 12/18/2017] [Indexed: 01/07/2023] Open
Abstract
Spinal Muscular Atrophy (SMA) is a neuromuscular disorder caused by mutations in the SMN1 gene. Being a monogenic disease, it is characterized by high clinical heterogeneity. Variations in penetrance and severity of symptoms, as well as clinical discrepancies between affected family members can result from modifier genes influence on disease manifestation. SMN2 gene copy number is known to be the main phenotype modifier and there is growing evidence of additional factors contributing to SMA severity. Potential modifiers of spinal muscular atrophy can be found among the wide variety of different factors, such as multiple proteins interacting with SMN or promoting motor neuron survival, epigenetic modifications, transcriptional or splicing factors influencing SMN2 expression. Study of these factors enables to reveal mechanisms underlying SMA pathology and can have pronounced clinical application.
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Affiliation(s)
- Marianna A. Maretina
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
- Saint Petersburg State University, Universitetskaya emb. 7/9, 199034Saint Petersburg, Russia
| | - Galina Y. Zheleznyakova
- Department of Clinical Neuroscience, Karolinska Institutet, Karolinska Universitetssjukhuset, 171 76 Stockholm, Sweden
| | - Kristina M. Lanko
- Saint Petersburg State Institute of Technology, Moskovsky prospect, 26, Saint Petersburg190013, Russia
| | - Anna A. Egorova
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
| | - Vladislav S. Baranov
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
- Saint Petersburg State University, Universitetskaya emb. 7/9, 199034Saint Petersburg, Russia
| | - Anton V. Kiselev
- D.O. Ott Research Institute of Obstetrics, Gynecology and Reproductology, Mendeleevskaya line, 3, Saint Petersburg199034, Russia
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25
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Ito YA, Smith AC, Kernohan KD, Pena IA, Ahmed A, McDonell LM, Beaulieu C, Bulman DE, Smidt A, Sawyer SL, Dyment DA, Boycott KM, Clericuzio CL. A ZPR1 mutation is associated with a novel syndrome of growth restriction, distinct craniofacial features, alopecia, and hypoplastic kidneys. Clin Genet 2018; 94:303-312. [PMID: 29851065 DOI: 10.1111/cge.13388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 05/24/2018] [Accepted: 05/27/2018] [Indexed: 12/24/2022]
Abstract
A novel autosomal recessive disorder characterized by pre- and postnatal growth restriction with microcephaly, distinctive craniofacial features, congenital alopecia, hypoplastic kidneys with renal insufficiency, global developmental delay, severe congenital sensorineural hearing loss, early mortality, hydrocephalus, and genital hypoplasia was observed in 4 children from 3 families of New Mexican Hispanic heritage. Three of the children died before 3 years of age from uremia and/or sepsis. Exome sequencing of the surviving individual identified a homozygous c.587T>C (p.Ile196Thr) mutation in ZPR1 Zinc Finger (ZPR1) that segregated appropriately in her family. In a second family, the identical variant was shown to be heterozygous in the affected individual's parents and not homozygous in any of her unaffected siblings. ZPR1 is a ubiquitously expressed, highly conserved protein postulated to transmit proliferative signals from the cell membrane to the nucleus. Structural modeling reveals that p.Ile196Thr disrupts the hydrophobic core of ZPR1. Patient fibroblast cells showed no detectable levels of ZPR1 and the cells showed a defect in cell cycle progression where a significant number of cells remained arrested in the G1 phase. We provide genetic and molecular evidence that a homozygous missense mutation in ZPR1 is associated with a rare and recognizable multisystem syndrome.
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Affiliation(s)
- Y A Ito
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - A C Smith
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - K D Kernohan
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - I A Pena
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - A Ahmed
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - L M McDonell
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - C Beaulieu
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - D E Bulman
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - A Smidt
- Division of Genetics/Dysmorphology, Department of Pediatrics, University of New Mexico School of Medicine, Albuquerque, New Mexico.,Department of Dermatology, University of New Mexico School of Medicine, Albuquerque, New Mexico
| | - S L Sawyer
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
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- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - D A Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - K M Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - C L Clericuzio
- Division of Genetics/Dysmorphology, Department of Pediatrics, University of New Mexico School of Medicine, Albuquerque, New Mexico
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26
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Shan Y, Cao W, Wang T, Jiang G, Zhang Y, Yang X. ZNF259 inhibits non-small cell lung cancer cells proliferation and invasion by FAK-AKT signaling. Cancer Manag Res 2017; 9:879-889. [PMID: 29276408 PMCID: PMC5733926 DOI: 10.2147/cmar.s150614] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Background Zinc finger protein 259 (ZNF259) is known to play essential roles in embryonic development and cell cycle regulation. However, its expression pattern and clinicopathological relevance remain unclear. Materials and methods A total of 114 lung cancer specimens were collected. The ZNF259 expression was measured between the lung cancer tissues and the adjacent normal lung tissues by immunohistochemical staining and Western blotting. Moreover, the correlation of ZNF259 expression with clinicopathological features was analyzed in 114 cases of lung cancer. Additionally, ZNF259 was depleted in the lung cancer cells in order to analyze its effect in the lung cancer. Results Immunohistochemical staining of 114 lung cancer specimens revealed significantly lower ZNF259 expression in lung cancer tissues than in adjacent normal lung tissues (53.5% vs 71.4%, P<0.001). In addition, ZNF259 downregulation was significantly associated with larger tumor size (P=0.001), advanced TNM stage (P=0.002), and positive lymph node metastasis (P=0.02). Western blotting of 20 paired lung cancer samples revealed lower ZNF259 protein levels in lung cancer tissues than in those of corresponding normal lung tissues (P=0.0032). Depletion of ZNF259 resulted in enhanced levels of p-FAK and p-AKT, CyclinD1, and MMP2, which in turn increased the proliferation and invasion of lung cancer cells. The effects of ZNF259 depletion were reversed by treatment with specific FAK or AKT inhibitors. Conclusion ZNF259 depletion is correlated with the development of non-small cell lung cancer (NSCLC) and serves as a predictor of adverse clinical outcome in NSCLC patients. The inhibitory effect of ZNF259 on proliferation and invasion can be attributed to downregulation of CyclinD1 and MMP2 via inactivation of the FAK-AKT pathway.
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Affiliation(s)
- Yuemei Shan
- Department of Pathology, Shengjing Hospital of China Medical University, Shenyang, China.,Department of Applied Technology, Institute of Technology of China Medical University, Shenyang, China
| | - Wei Cao
- Department of Pathology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Tao Wang
- Department of Pathology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Guiyang Jiang
- Department of Pathology, First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Yong Zhang
- Department of Pathology, Cancer Hospital of China Medical University, Shenyang, China
| | - Xianghong Yang
- Department of Pathology, Shengjing Hospital of China Medical University, Shenyang, China
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27
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Deregulation of ZPR1 causes respiratory failure in spinal muscular atrophy. Sci Rep 2017; 7:8295. [PMID: 28811488 PMCID: PMC5557895 DOI: 10.1038/s41598-017-07603-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 06/28/2017] [Indexed: 12/03/2022] Open
Abstract
Spinal muscular atrophy (SMA) is caused by the low levels of survival motor neuron (SMN) protein and is characterized by motor neuron degeneration and muscle atrophy. Respiratory failure causes death in SMA but the underlying molecular mechanism is unknown. The zinc finger protein ZPR1 interacts with SMN. ZPR1 is down regulated in SMA patients. We report that ZPR1 functions downstream of SMN to regulate HoxA5 levels in phrenic motor neurons that control respiration. Spatiotemporal inactivation of Zpr1 gene in motor neurons down-regulates HoxA5 and causes defects in the function of phrenic motor neurons that results in respiratory failure and perinatal lethality in mice. Modulation in ZPR1 levels directly correlates and influences levels of HoxA5 transcription. In SMA mice, SMN-deficiency causes down-regulation of ZPR1 and HoxA5 that result in degeneration of phrenic motor neurons. Identification of ZPR1 and HoxA5 as potential targets provides a paradigm for developing strategies to treat respiratory distress in SMA.
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28
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Raimer AC, Gray KM, Matera AG. SMN - A chaperone for nuclear RNP social occasions? RNA Biol 2017; 14:701-711. [PMID: 27648855 PMCID: PMC5519234 DOI: 10.1080/15476286.2016.1236168] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/01/2016] [Accepted: 09/09/2016] [Indexed: 12/24/2022] Open
Abstract
Survival Motor Neuron (SMN) protein localizes to both the nucleus and the cytoplasm. Cytoplasmic SMN is diffusely localized in large oligomeric complexes with core member proteins, called Gemins. Biochemical and cell biological studies have demonstrated that the SMN complex is required for the cytoplasmic assembly and nuclear transport of Sm-class ribonucleoproteins (RNPs). Nuclear SMN accumulates with spliceosomal small nuclear (sn)RNPs in Cajal bodies, sub-domains involved in multiple facets of snRNP maturation. Thus, the SMN complex forms stable associations with both nuclear and cytoplasmic snRNPs, and plays a critical role in their biogenesis. In this review, we focus on potential functions of the nuclear SMN complex, with particular emphasis on its role within the Cajal body.
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Affiliation(s)
- Amanda C. Raimer
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kelsey M. Gray
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - A. Gregory Matera
- Curriculum in Genetics and Molecular Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Integrative Program for Biological and Genome Sciences, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Genetics, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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29
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Singh RN, Howell MD, Ottesen EW, Singh NN. Diverse role of survival motor neuron protein. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2017; 1860:299-315. [PMID: 28095296 PMCID: PMC5325804 DOI: 10.1016/j.bbagrm.2016.12.008] [Citation(s) in RCA: 178] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 02/07/2023]
Abstract
The multifunctional Survival Motor Neuron (SMN) protein is required for the survival of all organisms of the animal kingdom. SMN impacts various aspects of RNA metabolism through the formation and/or interaction with ribonucleoprotein (RNP) complexes. SMN regulates biogenesis of small nuclear RNPs, small nucleolar RNPs, small Cajal body-associated RNPs, signal recognition particles and telomerase. SMN also plays an important role in DNA repair, transcription, pre-mRNA splicing, histone mRNA processing, translation, selenoprotein synthesis, macromolecular trafficking, stress granule formation, cell signaling and cytoskeleton maintenance. The tissue-specific requirement of SMN is dictated by the variety and the abundance of its interacting partners. Reduced expression of SMN causes spinal muscular atrophy (SMA), a leading genetic cause of infant mortality. SMA displays a broad spectrum ranging from embryonic lethality to an adult onset. Aberrant expression and/or localization of SMN has also been associated with male infertility, inclusion body myositis, amyotrophic lateral sclerosis and osteoarthritis. This review provides a summary of various SMN functions with implications to a better understanding of SMA and other pathological conditions.
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Affiliation(s)
- Ravindra N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States.
| | - Matthew D Howell
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Eric W Ottesen
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
| | - Natalia N Singh
- Department of Biomedical Sciences, Iowa State University, Ames, IA 50011, United States
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30
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Kiełbowicz-Matuk A, Czarnecka J, Banachowicz E, Rey P, Rorat T. Solanum tuberosum ZPR1 encodes a light-regulated nuclear DNA-binding protein adjusting the circadian expression of StBBX24 to light cycle. PLANT, CELL & ENVIRONMENT 2017; 40:424-440. [PMID: 27928822 DOI: 10.1111/pce.12875] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 11/14/2016] [Accepted: 11/16/2016] [Indexed: 06/06/2023]
Abstract
ZPR1 proteins belong to the C4-type of zinc finger coordinators known in animal cells to interact with other proteins and participate in cell growth and proliferation. In contrast, the current knowledge regarding plant ZPR1 proteins is very scarce. Here, we identify a novel potato nuclear factor belonging to this family and named StZPR1. StZPR1 is specifically expressed in photosynthetic organs during the light period, and the ZPR1 protein is located in the nuclear chromatin fraction. From modelling and experimental analyses, we reveal the StZPR1 ability to bind the circadian DNA cis motif 'CAACAGCATC', named CIRC and present in the promoter of the clock-controlled double B-box StBBX24 gene, the expression of which peaks in the middle of the day. We found that transgenic lines silenced for StZPR1 expression still display a 24 h period for the oscillation of StBBX24 expression but delayed by 4 h towards the night. Importantly, other BBX genes exhibit altered circadian regulation in these lines. Our data demonstrate that StZPR1 allows fitting of the StBBX24 circadian rhythm to the light period and provide evidence that ZPR1 is a novel clock-associated protein in plants necessary for the accurate rhythmic expression of specific circadian-regulated genes.
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Affiliation(s)
| | - Jagoda Czarnecka
- Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznań, Poland
| | - Ewa Banachowicz
- Molecular Biophysics Department, Faculty of Physics, Adam Mickiewicz University, Umultowska 85, 61-614, Poznań, Poland
| | - Pascal Rey
- CEA, DRF, BIAM, Laboratoire d'Ecophysiologie Moléculaire des Plantes, Saint-Paul-lez-Durance, F-13108, France
- CNRS, UMR 7265 Biologie Végétale & Microbiologie Environnementale, Saint-Paul-lez-Durance, F-13108, France
- Aix-Marseille Université, Saint-Paul-lez-Durance, F-13108, France
| | - Tadeusz Rorat
- Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznań, Poland
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31
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Altered mRNA Splicing in SMN-Depleted Motor Neuron-Like Cells. PLoS One 2016; 11:e0163954. [PMID: 27736905 PMCID: PMC5063418 DOI: 10.1371/journal.pone.0163954] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 09/16/2016] [Indexed: 11/23/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an intractable neurodegenerative disease afflicting 1 in 6–10,000 live births. One of the key functions of the SMN protein is regulation of spliceosome assembly. Reduced levels of the SMN protein that are observed in SMA have been shown to result in aberrant mRNA splicing. SMN-dependent mis-spliced transcripts in motor neurons may cause stresses that are particularly harmful and may serve as potential targets for the treatment of motor neuron disease or as biomarkers in the SMA patient population. We performed deep RNA sequencing using motor neuron-like NSC-34 cells to screen for SMN-dependent mRNA processing changes that occur following acute depletion of SMN. We identified SMN-dependent splicing changes, including an intron retention event that results in the production of a truncated Rit1 transcript. This intron-retained transcript is stable and is mis-spliced in spinal cord from symptomatic SMA mice. Constitutively active Rit1 ameliorated the neurite outgrowth defect in SMN depleted NSC-34 cells, while expression of the truncated protein product of the mis-spliced Rit1 transcript inhibited neurite extension. These results reveal new insights into the biological consequence of SMN-dependent splicing in motor neuron-like cells.
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32
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Hebert MD, Poole AR. Towards an understanding of regulating Cajal body activity by protein modification. RNA Biol 2016; 14:761-778. [PMID: 27819531 DOI: 10.1080/15476286.2016.1243649] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The biogenesis of small nuclear ribonucleoproteins (snRNPs), small Cajal body-specific RNPs (scaRNPs), small nucleolar RNPs (snoRNPs) and the telomerase RNP involves Cajal bodies (CBs). Although many components enriched in the CB contain post-translational modifications (PTMs), little is known about how these modifications impact individual protein function within the CB and, in concert with other modified factors, collectively regulate CB activity. Since all components of the CB also reside in other cellular locations, it is also important that we understand how PTMs affect the subcellular localization of CB components. In this review, we explore the current knowledge of PTMs on the activity of proteins known to enrich in CBs in an effort to highlight current progress as well as illuminate paths for future investigation.
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Affiliation(s)
- Michael D Hebert
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
| | - Aaron R Poole
- a Department of Biochemistry , The University of Mississippi Medical Center , Jackson , MS , USA
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33
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Tsigelny IF, Kouznetsova VL, Lian N, Kesari S. Molecular mechanisms of OLIG2 transcription factor in brain cancer. Oncotarget 2016; 7:53074-53101. [PMID: 27447975 PMCID: PMC5288170 DOI: 10.18632/oncotarget.10628] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/03/2016] [Indexed: 12/13/2022] Open
Abstract
Oligodendrocyte lineage transcription factor 2 (OLIG2) plays a pivotal role in glioma development. Here we conducted a comprehensive study of the critical gene regulatory networks involving OLIG2. These include the networks responsible for OLIG2 expression, its translocation to nucleus, cell cycle, epigenetic regulation, and Rho-pathway interactions. We described positive feedback loops including OLIG2: loops of epigenetic regulation and loops involving receptor tyrosine kinases. These loops may be responsible for the prolonged oncogenic activity of OLIG2. The proposed schemes for epigenetic regulation of the gene networks involving OLIG2 are confirmed by patient survival (Kaplan-Meier) curves based on the cancer genome atlas (TCGA) datasets. Finally, we elucidate the Coherent-Gene Modules (CGMs) networks-framework of OLIG2 involvement in cancer. We showed that genes interacting with OLIG2 formed eight CGMs having a set of intermodular connections. We showed also that among the genes involved in these modules the most connected hub is EGFR, then, on lower level, HSP90 and CALM1, followed by three lower levels including epigenetic genes KDM1A and NCOR1. The genes on the six upper levels of the hierarchy are involved in interconnections of all eight CGMs and organize functionally defined gene-signaling subnetworks having specific functions. For example, CGM1 is involved in epigenetic control. CGM2 is significantly related to cell proliferation and differentiation. CGM3 includes a number of interconnected helix-loop-helix transcription factors (bHLH) including OLIG2. Many of these TFs are partially controlled by OLIG2. The CGM4 is involved in PDGF-related: angiogenesis, tumor cell proliferation and differentiation. These analyses provide testable hypotheses and approaches to inhibit OLIG2 pathway and relevant feed-forward and feedback loops to be interrogated. This broad approach can be applied to other TFs.
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Affiliation(s)
- Igor F. Tsigelny
- Department of Neurosciences, University of California San Diego, La Jolla, 92093-0752, CA, USA
- San Diego Supercomputer Center, University of California San Diego, La Jolla, 92093-0505, CA, USA
- Moores Cancer Center, University of California San Diego, La Jolla, 92093, CA, USA
| | - Valentina L. Kouznetsova
- San Diego Supercomputer Center, University of California San Diego, La Jolla, 92093-0505, CA, USA
- Moores Cancer Center, University of California San Diego, La Jolla, 92093, CA, USA
| | - Nathan Lian
- REHS, San Diego Supercomputer Center, University of California San Diego, La Jolla, 92093-0505, CA, USA
| | - Santosh Kesari
- John Wayne Cancer Institute at Providence Saint John's Health Center, Santa Monica, 90404, CA, USA
- Pacific Neuroscience Institute at Providence Saint John's Health Center, Santa Monica, 90404, CA, USA
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Ahmad S, Bhatia K, Kannan A, Gangwani L. Molecular Mechanisms of Neurodegeneration in Spinal Muscular Atrophy. J Exp Neurosci 2016; 10:39-49. [PMID: 27042141 PMCID: PMC4807884 DOI: 10.4137/jen.s33122] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 02/22/2016] [Accepted: 02/25/2016] [Indexed: 02/07/2023] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease with a high incidence and is the most common genetic cause of infant mortality. SMA is primarily characterized by degeneration of the spinal motor neurons that leads to skeletal muscle atrophy followed by symmetric limb paralysis, respiratory failure, and death. In humans, mutation of the Survival Motor Neuron 1 (SMN1) gene shifts the load of expression of SMN protein to the SMN2 gene that produces low levels of full-length SMN protein because of alternative splicing, which are sufficient for embryonic development and survival but result in SMA. The molecular mechanisms of the (a) regulation of SMN gene expression and (b) degeneration of motor neurons caused by low levels of SMN are unclear. However, some progress has been made in recent years that have provided new insights into understanding of the cellular and molecular basis of SMA pathogenesis. In this review, we have briefly summarized recent advances toward understanding of the molecular mechanisms of regulation of SMN levels and signaling mechanisms that mediate neurodegeneration in SMA.
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Affiliation(s)
- Saif Ahmad
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center, El Paso, Texas, USA.; Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, USA
| | - Kanchan Bhatia
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center, El Paso, Texas, USA.; Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, USA
| | - Annapoorna Kannan
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center, El Paso, Texas, USA.; Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, USA
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences, Texas Tech University Health Sciences Center, El Paso, Texas, USA.; Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, Texas, USA
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Genabai NK, Ahmad S, Zhang Z, Jiang X, Gabaldon CA, Gangwani L. Genetic inhibition of JNK3 ameliorates spinal muscular atrophy. Hum Mol Genet 2015; 24:6986-7004. [PMID: 26423457 DOI: 10.1093/hmg/ddv401] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/21/2015] [Indexed: 01/04/2023] Open
Abstract
Mutation of the Survival Motor Neuron 1 (SMN1) gene causes spinal muscular atrophy (SMA), an autosomal recessive neurodegenerative disorder that occurs in early childhood. Degeneration of spinal motor neurons caused by SMN deficiency results in progressive muscle atrophy and death in SMA. The molecular mechanism underlying neurodegeneration in SMA is unknown. No treatment is available to prevent neurodegeneration and reduce the burden of illness in SMA. We report that the c-Jun NH2-terminal kinase (JNK) signaling pathway mediates neurodegeneration in SMA. The neuron-specific isoform JNK3 is required for neuron degeneration caused by SMN deficiency. JNK3 deficiency reduces degeneration of cultured neurons caused by low levels of SMN. Genetic inhibition of JNK pathway in vivo by Jnk3 knockout results in amelioration of SMA phenotype. JNK3 deficiency prevents the loss of spinal cord motor neurons, reduces muscle degeneration, improves muscle fiber thickness and muscle growth, improves motor function and overall growth and increases lifespan of mice with SMA that shows a systemic rescue of phenotype by a SMN-independent mechanism. JNK3 represents a potential (non-SMN) therapeutic target for the treatment of SMA.
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Affiliation(s)
- Naresh K Genabai
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Saif Ahmad
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Zhanying Zhang
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Xiaoting Jiang
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Cynthia A Gabaldon
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
| | - Laxman Gangwani
- Center of Emphasis in Neurosciences and Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech University Health Sciences Center, El Paso, TX 79905, USA
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Generation of a Zinc Finger Protein ZPR1 Mutant That Constitutively Interacted with Translation Elongation Factor 1α. Biosci Biotechnol Biochem 2014; 73:2809-11. [DOI: 10.1271/bbb.90745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Abstract
This review summarizes the current understanding of the role of nuclear bodies in regulating gene expression. The compartmentalization of cellular processes, such as ribosome biogenesis, RNA processing, cellular response to stress, transcription, modification and assembly of spliceosomal snRNPs, histone gene synthesis and nuclear RNA retention, has significant implications for gene regulation. These functional nuclear domains include the nucleolus, nuclear speckle, nuclear stress body, transcription factory, Cajal body, Gemini of Cajal body, histone locus body and paraspeckle. We herein review the roles of nuclear bodies in regulating gene expression and their relation to human health and disease.
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Affiliation(s)
| | - Cornelius F. Boerkoel
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +1-604-875-2157; Fax: +1-604-875-2376
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Abstract
Neuromuscular diseases, which encompass disorders that affect muscle and its innervation, are highly heritable. Genetic diagnosis now frequently pinpoints the primary mutation responsible for a given neuromuscular disease. However, the results from genetic testing indicate that neuromuscular disease phenotypes may vary widely, even in individuals with the same primary disease-causing mutation. Clinical variability arises from both genetic and environmental factors. Genetic modifiers can now be identified using candidate gene as well as genomic approaches. The presence of genetic modifiers for neuromuscular disease helps define the clinical outcome and also highlights pathways of potential therapeutic utility. Herein, we will focus on single gene neuromuscular disorders, including muscular dystrophy, spinal muscular atrophy, and amyotrophic lateral sclerosis, and the methods that have been used to identify modifier genes. Animal models have been an invaluable resource for modifier gene discovery and subsequent mechanistic studies. Some modifiers, identified using animal models, have successfully translated to the human counterpart. Furthermore, in a few instances, modifier gene discovery has repetitively uncovered the same pathway, such as TGFβ signaling in muscular dystrophy, further emphasizing the relevance of that pathway. Knowledge of genetic factors that influence disease can have direct clinical applications for prognosis and predicted outcome.
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Affiliation(s)
- Kay-Marie Lamar
- Department of Human Genetics, Department of Medicine, Section of Cardiology, The University of Chicago, Chicago, IL, USA
| | - Elizabeth M McNally
- Department of Human Genetics, Department of Medicine, Section of Cardiology, The University of Chicago, Chicago, IL, USA
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Aung LHH, Yin RX, Wu DF, Wang W, Wu JZ, Liu CW. Sex-specific association of the zinc finger protein 259 rs2075290 polymorphism and serum lipid levels. Int J Med Sci 2014; 11:471-8. [PMID: 24688311 PMCID: PMC3970100 DOI: 10.7150/ijms.8489] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 02/27/2014] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Little is known about the association of ZNF259 rs2075290 single nucleotide polymorphism (SNP) and serum lipid levels in the Chinese population. This study aimed to detect the association of ZNF259 rs2075290 SNP and environmental factors with serum lipid levels between males and females in the Mulao and Han populations. METHODS AND RESULTS Genotyping of ZNF259 rs2075290 SNP was performed in 788 of Mulao and 778 of Han participants using polymerase chain reaction and restriction fragment length polymorphism. The genotype frequencies were significantly different between Mulao and Han populations (AA, 50.1% Vs 58.9%; AG, 42.3% Vs 35.7%; GG, 7.6% Vs 5.4%, P = 0.002) and between Han males and females (AA, 64.5% Vs 55.2%; AG, 28.3% Vs 40.6%; GG, 7.2% Vs 4.2%, P = 0.001). Serum levels of triglyceride (TG) in Mulao males, and total cholesterol (TC), TG and low-density lipoprotein cholesterol (LDL-C) in Mulao females were different between the AA and AG/GG genotypes (P < 0.05-0.001). Serum TC, LDL-C and apolipoprotein (Apo) A1 levels in Han males, and TG and ApoB levels and ApoA1/ApoB ratio in Han females were different between the AA and AG/GG genotypes (P < 0.05-0.001). An interaction between ZNF259 rs2075290 polymorphism and male gender on serum TC, LDL-C, and ApoA1 levels was noted in Han population (P < 0.05-0.01) but not in Mulao's. CONCLUSIONS The subjects with AG/GG genotype in Mulao males and females and Han females have less favorable lipid profiles than those with AA genotype. In contrast, the subjects with AG/GG genotype in Han males have more favorable lipid profiles than those with AA genotype. These findings suggest that the association between ZNF259 rs2075290 SNP and serum lipid levels might have ethnic- and/or sex-specificity.
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Affiliation(s)
- Lynn Htet Htet Aung
- 1. Department of Cardiology, Institute of Cardiovascular Diseases, the First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Rui-Xing Yin
- 1. Department of Cardiology, Institute of Cardiovascular Diseases, the First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Dong-Feng Wu
- 1. Department of Cardiology, Institute of Cardiovascular Diseases, the First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Wei Wang
- 1. Department of Cardiology, Institute of Cardiovascular Diseases, the First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Jin-Zhen Wu
- 1. Department of Cardiology, Institute of Cardiovascular Diseases, the First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, People's Republic of China
| | - Cheng-Wu Liu
- 2. Department of Pathophysiology, School of Premedical Sciences, Guangxi Medical University, Nanning, Guangxi, People's Republic of China
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Förthmann B, van Bergeijk J, Lee YW, Lübben V, Schill Y, Brinkmann H, Ratzka A, Stachowiak MK, Hebert M, Grothe C, Claus P. Regulation of neuronal differentiation by proteins associated with nuclear bodies. PLoS One 2013; 8:e82871. [PMID: 24358231 PMCID: PMC3866168 DOI: 10.1371/journal.pone.0082871] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 11/06/2013] [Indexed: 12/17/2022] Open
Abstract
Nuclear bodies are large sub-nuclear structures composed of RNA and protein molecules. The Survival of Motor Neuron (SMN) protein localizes to Cajal bodies (CBs) and nuclear gems. Diminished cellular concentration of SMN is associated with the neurodegenerative disease Spinal Muscular Atrophy (SMA). How nuclear body architecture and its structural components influence neuronal differentiation remains elusive. In this study, we analyzed the effects of SMN and two of its interaction partners in cellular models of neuronal differentiation. The nuclear 23 kDa isoform of Fibroblast Growth Factor - 2 (FGF-2(23)) is one of these interacting proteins - and was previously observed to influence nuclear bodies by destabilizing nuclear gems and mobilizing SMN from Cajal bodies (CBs). Here we demonstrate that FGF-2(23) blocks SMN-promoted neurite outgrowth, and also show that SMN disrupts FGF-2(23)-dependent transcription. Our results indicate that FGF-2(23) and SMN form an inactive complex that interferes with neuronal differentiation by mutually antagonizing nuclear functions. Coilin is another nuclear SMN binding partner and a marker protein for Cajal bodies (CBs). In addition, coilin is essential for CB function in maturation of small nuclear ribonucleoprotein particles (snRNPs). The role of coilin outside of Cajal bodies and its putative impacts in tissue differentiation are poorly defined. The present study shows that protein levels of nucleoplasmic coilin outside of CBs decrease during neuronal differentiation. Overexpression of coilin has an inhibitory effect on neurite outgrowth. Furthermore, we find that nucleoplasmic coilin inhibits neurite outgrowth independent of SMN binding revealing a new function for coilin in neuronal differentiation.
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Affiliation(s)
- Benjamin Förthmann
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Hannover, Germany
| | | | - Yu-Wei Lee
- Department of Pathology and Anatomical Sciences, State University of New York, Buffalo, New York, United States of America
| | - Verena Lübben
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Yvonne Schill
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Hella Brinkmann
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Andreas Ratzka
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Michal K. Stachowiak
- Department of Pathology and Anatomical Sciences, State University of New York, Buffalo, New York, United States of America
| | - Michael Hebert
- Department of Biochemistry, The University of Mississippi Medical Center, Jackson, Mississippi, United States of America
| | - Claudia Grothe
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neuroscience, University of Veterinary Medicine Hannover, Hannover, Germany
- * E-mail:
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THEME 9IN VIVOEXPERIMENTAL MODELS. Amyotroph Lateral Scler Frontotemporal Degener 2013. [DOI: 10.3109/21678421.2013.838424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Overexpression of survival motor neuron improves neuromuscular function and motor neuron survival in mutant SOD1 mice. Neurobiol Aging 2013; 35:906-15. [PMID: 24210254 PMCID: PMC3919158 DOI: 10.1016/j.neurobiolaging.2013.09.030] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/03/2013] [Accepted: 09/19/2013] [Indexed: 12/14/2022]
Abstract
Spinal muscular atrophy results from diminished levels of survival motor neuron (SMN) protein in spinal motor neurons. Low levels of SMN also occur in models of amyotrophic lateral sclerosis (ALS) caused by mutant superoxide dismutase 1 (SOD1) and genetic reduction of SMN levels exacerbates the phenotype of transgenic SOD1G93A mice. Here, we demonstrate that SMN protein is significantly reduced in the spinal cords of patients with sporadic ALS. To test the potential of SMN as a modifier of ALS, we overexpressed SMN in 2 different strains of SOD1G93A mice. Neuronal overexpression of SMN significantly preserved locomotor function, rescued motor neurons, and attenuated astrogliosis in spinal cords of SOD1G93A mice. Despite this, survival was not prolonged, most likely resulting from SMN mislocalization and depletion of gems in motor neurons of symptomatic mice. Our results reveal that SMN upregulation slows locomotor deficit onset and motor neuron loss in this mouse model of ALS. However, disruption of SMN nuclear complexes by high levels of mutant SOD1, even in the presence of SMN overexpression, might limit its survival promoting effects in this specific mouse model. Studies in emerging mouse models of ALS are therefore warranted to further explore the potential of SMN as a modifier of ALS.
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Förthmann B, Brinkmann H, Ratzka A, Stachowiak MK, Grothe C, Claus P. Immobile survival of motoneuron (SMN) protein stored in Cajal bodies can be mobilized by protein interactions. Cell Mol Life Sci 2013; 70:2555-68. [PMID: 23334184 PMCID: PMC11113639 DOI: 10.1007/s00018-012-1242-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 11/29/2012] [Accepted: 12/10/2012] [Indexed: 12/25/2022]
Abstract
Reduced levels of survival of motoneuron (SMN) protein lead to spinal muscular atrophy, but it is still unknown how SMN protects motoneurons in the spinal cord against degeneration. In the nucleus, SMN is associated with two types of nuclear bodies denoted as gems and Cajal bodies (CBs). The 23 kDa isoform of fibroblast growth factor-2 (FGF-2(23)) is a nuclear protein that binds to SMN and destabilizes the SMN-Gemin2 complex. In the present study, we show that FGF-2(23) depletes SMN from CBs without affecting their general structure. FRAP analysis of SMN-EGFP in CBs demonstrated that the majority of SMN in CBs remained mobile and allowed quantification of fast, slow and immobile nuclear SMN populations. The potential for SMN release was confirmed by in vivo photoconversion of SMN-Dendra2, indicating that CBs concentrate immobile SMN that could have a specialized function in CBs. FGF-2(23) accelerated SMN release from CBs, accompanied by a conversion of immobile SMN into a mobile population. Furthermore, FGF-2(23) caused snRNP accumulation in CBs. We propose a model in which Cajal bodies store immobile SMN that can be mobilized by its nuclear interaction partner FGF-2(23), leading to U4 snRNP accumulation in CBs, indicating a role for immobile SMN in tri-snRNP assembly.
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Affiliation(s)
- Benjamin Förthmann
- Institute of Neuroanatomy, Hannover Medical School, OE 4140, Carl-Neuberg-Str.1, 30625 Hannover, Germany
- Center for Systems Neuroscience, 30625 Hannover, Germany
| | - Hella Brinkmann
- Institute of Neuroanatomy, Hannover Medical School, OE 4140, Carl-Neuberg-Str.1, 30625 Hannover, Germany
| | - Andreas Ratzka
- Institute of Neuroanatomy, Hannover Medical School, OE 4140, Carl-Neuberg-Str.1, 30625 Hannover, Germany
| | - Michal K. Stachowiak
- Department of Pathology and Anatomical Sciences, State University of New York, Buffalo, NY 14214 USA
| | - Claudia Grothe
- Institute of Neuroanatomy, Hannover Medical School, OE 4140, Carl-Neuberg-Str.1, 30625 Hannover, Germany
- Center for Systems Neuroscience, 30625 Hannover, Germany
| | - Peter Claus
- Institute of Neuroanatomy, Hannover Medical School, OE 4140, Carl-Neuberg-Str.1, 30625 Hannover, Germany
- Center for Systems Neuroscience, 30625 Hannover, Germany
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Genetic circuitry of Survival motor neuron, the gene underlying spinal muscular atrophy. Proc Natl Acad Sci U S A 2013; 110:E2371-80. [PMID: 23757500 DOI: 10.1073/pnas.1301738110] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The clinical severity of the neurodegenerative disorder spinal muscular atrophy (SMA) is dependent on the levels of functional Survival Motor Neuron (SMN) protein. Consequently, current strategies for developing treatments for SMA generally focus on augmenting SMN levels. To identify additional potential therapeutic avenues and achieve a greater understanding of SMN, we applied in vivo, in vitro, and in silico approaches to identify genetic and biochemical interactors of the Drosophila SMN homolog. We identified more than 300 candidate genes that alter an Smn-dependent phenotype in vivo. Integrating the results from our genetic screens, large-scale protein interaction studies, and bioinformatic analysis, we define a unique interactome for SMN that provides a knowledge base for a better understanding of SMA.
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Hebert MD. Signals controlling Cajal body assembly and function. Int J Biochem Cell Biol 2013; 45:1314-7. [PMID: 23583661 DOI: 10.1016/j.biocel.2013.03.019] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 03/28/2013] [Accepted: 03/29/2013] [Indexed: 10/27/2022]
Abstract
Cajal bodies (CBs) are subnuclear domains that participate in the biogenesis of small nuclear ribonucleoproteins (snRNPs) and telomerase. CBs are found in cells with high splicing demands, such as neuronal and cancer cells. The purpose of this review is to highlight what is known about the signals that impact the formation and activity of CBs. Particular attention is paid to phosphorylation as a major regulator of CB formation and composition, but a non-biochemical mediated pathway (mechanotransduction) that impacts CBs is also discussed. Amongst the CB components, recently published work on coilin (the CB marker protein) strongly suggests that this protein, and the CB by extension, is a global sensor that responds to environmental signals. Disruption of these signals, which would result in a decreased capacity to generate snRNPs and telomerase, is predicted to be beneficial in the treatment of cancer.
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Affiliation(s)
- Michael D Hebert
- Department of Biochemistry, The University of Mississippi Medical Center, Jackson, MS 39216 4505, USA.
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46
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Anderton RS, Meloni BP, Mastaglia FL, Boulos S. Spinal muscular atrophy and the antiapoptotic role of survival of motor neuron (SMN) protein. Mol Neurobiol 2013; 47:821-32. [PMID: 23315303 DOI: 10.1007/s12035-013-8399-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2012] [Accepted: 01/03/2013] [Indexed: 11/26/2022]
Abstract
Spinal muscular atrophy (SMA) is a devastating and often fatal neurodegenerative disease that affects spinal motor neurons and leads to progressive muscle wasting and paralysis. The survival of motor neuron (SMN) gene is mutated or deleted in most forms of SMA, which results in a critical reduction in SMN protein. Motor neurons appear particularly vulnerable to reduced SMN protein levels. Therefore, understanding the functional role of SMN in protecting motor neurons from degeneration is an essential prerequisite for the design of effective therapies for SMA. To this end, there is increasing evidence indicating a key regulatory antiapoptotic role for the SMN protein that is important in motor neuron survival. The aim of this review is to highlight key findings that support an antiapoptotic role for SMN in modulating cell survival and raise possibilities for new therapeutic approaches.
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Affiliation(s)
- Ryan S Anderton
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia and Australian Neuromuscular Research Institute, Nedlands, Western Australia, Australia.
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Singh NN, Seo J, Rahn SJ, Singh RN. A multi-exon-skipping detection assay reveals surprising diversity of splice isoforms of spinal muscular atrophy genes. PLoS One 2012. [PMID: 23185376 PMCID: PMC3501452 DOI: 10.1371/journal.pone.0049595] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Humans have two near identical copies of Survival Motor Neuron gene: SMN1 and SMN2. Loss of SMN1 coupled with the predominant skipping of SMN2 exon 7 causes spinal muscular atrophy (SMA), a neurodegenerative disease. SMA patient cells devoid of SMN1 provide a powerful system to examine splicing pattern of various SMN2 exons. Until now, similar system to examine splicing of SMN1 exons was unavailable. We have recently screened several patient cell lines derived from various diseases, including SMA, Alzheimer’s disease, Parkinson’s disease and Batten disease. Here we report a Batten disease cell line that lacks functional SMN2, as an ideal system to examine pre-mRNA splicing of SMN1. We employ a multiple-exon-skipping detection assay (MESDA) to capture simultaneously skipping of multiple exons. Our results show surprising diversity of splice isoforms and reveal novel splicing events that include skipping of exon 4 and co-skipping of three adjacent exons of SMN. Contrary to the general belief, MESDA captured oxidative-stress induced skipping of SMN1 exon 5 in several cell types, including non-neuronal cells. We further demonstrate that the predominant SMN2 exon 7 skipping induced by oxidative stress is modulated by a combinatorial control that includes promoter sequence, endogenous context, and the weak splice sites. We also show that an 8-mer antisense oligonucleotide blocking a recently described GC-rich sequence prevents SMN2 exon 7 skipping under the conditions of oxidative stress. Our findings bring new insight into splicing regulation of an essential housekeeping gene linked to neurodegeneration and infant mortality.
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Affiliation(s)
- Natalia N. Singh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Joonbae Seo
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Sarah J. Rahn
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
| | - Ravindra N. Singh
- Department of Biomedical Sciences, Iowa State University, Ames, Iowa, United States of America
- * E-mail:
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Machyna M, Heyn P, Neugebauer KM. Cajal bodies: where form meets function. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 4:17-34. [PMID: 23042601 DOI: 10.1002/wrna.1139] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cell nucleus contains dozens of subcompartments that separate biochemical processes into confined spaces. Cajal bodies (CBs) were discovered more than 100 years ago, but only extensive research in the past decades revealed the surprising complexity of molecular and cellular functions taking place in these structures. Many protein and RNA species are modified and assembled within CBs, which have emerged as a meeting place and factory for ribonucleoprotein (RNP) particles involved in splicing, ribosome biogenesis and telomere maintenance. Recently, a distinct structure near histone gene clusters--the Histone locus body (HLB)--was discovered. Involved in histone mRNA 3'-end formation, HLBs can share several components with CBs. Whether the appearance of distinct HLBs is simply a matter of altered affinity between these structures or of an alternate mode of CB assembly is unknown. However, both structures share basic assembly properties, in which transcription plays a decisive role in initiation. After this seeding event, additional components associate in random order. This appears to be a widespread mechanism for body assembly. CB assembly encompasses an additional layer of complexity, whereby a set of pre-existing substructures can be integrated into mature CBs. We propose this as a multi-seeding model of CB assembly.
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Affiliation(s)
- Martin Machyna
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
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Griffiths LA, Doig J, Churchhouse AMD, Davies FCJ, Squires CE, Newbery HJ, Abbott CM. Haploinsufficiency for translation elongation factor eEF1A2 in aged mouse muscle and neurons is compatible with normal function. PLoS One 2012; 7:e41917. [PMID: 22848658 PMCID: PMC3405021 DOI: 10.1371/journal.pone.0041917] [Citation(s) in RCA: 12] [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: 05/10/2012] [Accepted: 06/28/2012] [Indexed: 11/19/2022] Open
Abstract
Translation elongation factor isoform eEF1A2 is expressed in muscle and neurons. Deletion of eEF1A2 in mice gives rise to the neurodegenerative phenotype "wasted" (wst). Mice homozygous for the wasted mutation die of muscle wasting and neurodegeneration at four weeks post-natal. Although the mutation is said to be recessive, aged heterozygous mice have never been examined in detail; a number of other mouse models of motor neuron degeneration have recently been shown to have similar, albeit less severe, phenotypic abnormalities in the heterozygous state. We therefore examined the effects of ageing on a cohort of heterozygous +/wst mice and control mice, in order to establish whether a presumed 50% reduction in eEF1A2 expression was compatible with normal function. We evaluated the grip strength assay as a way of distinguishing between wasted and wild-type mice at 3-4 weeks, and then performed the same assay in older +/wst and wild-type mice. We also used rotarod performance and immunohistochemistry of spinal cord sections to evaluate the phenotype of aged heterozygous mice. Heterozygous mutant mice showed no deficit in neuromuscular function or signs of spinal cord pathology, in spite of the low levels of eEF1A2.
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Affiliation(s)
- Lowri A. Griffiths
- Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Jennifer Doig
- Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Antonia M. D. Churchhouse
- Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Faith C. J. Davies
- Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Charlotte E. Squires
- Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Helen J. Newbery
- Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Catherine M. Abbott
- Centre for Molecular Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
- * E-mail:
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Anderton RS, Price LL, Turner BJ, Meloni BP, Mitrpant C, Mastaglia FL, Goh C, Wilton SD, Boulos S. Co-regulation of survival of motor neuron and Bcl-xL expression: implications for neuroprotection in spinal muscular atrophy. Neuroscience 2012; 220:228-36. [PMID: 22732506 DOI: 10.1016/j.neuroscience.2012.06.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2012] [Revised: 06/15/2012] [Accepted: 06/18/2012] [Indexed: 11/29/2022]
Abstract
Spinal muscular atrophy (SMA), a fatal genetic motor disorder of infants, is caused by diminished full-length survival of motor neuron (SMN) protein levels. Normally involved in small nuclear ribonucleoprotein (snRNP) assembly and pre-mRNA splicing, recent studies suggest that SMN plays a critical role in regulating apoptosis. Interestingly, the anti-apoptotic Bcl-x isoform, Bcl-xL, is reduced in SMA. In a related finding, Sam68, an RNA-binding protein, was found to modulate splicing of SMN and Bcl-xL transcripts, promoting SMNΔ7 and pro-apoptotic Bcl-xS transcripts. Here we demonstrate that Bcl-xL expression increases SMN protein by ∼2-fold in SH-SY5Y cells. Conversely, SMN expression increases Bcl-xL protein levels by ∼6-fold in SH-SY5Y cells, and ∼2.5-fold in the brains of transgenic mice over-expressing SMN (PrP-SMN). Moreover, Sam68 protein levels were markedly reduced following SMN and Bcl-xL expression in SH-SY5Y cells, suggesting a feedback mechanism co-regulating levels of both proteins. We also found that exogenous SMN expression increased full-length SMN transcripts, possibly by promoting exon 7 inclusion. Finally, co-expression of SMN and Bcl-xL produced an additive anti-apoptotic effect following PI3-kinase inhibition in SH-SY5Y cells. Our findings implicate Bcl-xL as another potential target in SMA therapeutics, and indicate that therapeutic increases in SMN may arise from modest increases in total SMN.
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Affiliation(s)
- R S Anderton
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Australian Neuromuscular Research Institute, Western Australia, Australia.
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