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Prabhakaran V, Melchels FP, Murray LM, Paxton JZ. Engineering three-dimensional bone macro-tissues by guided fusion of cell spheroids. Front Endocrinol (Lausanne) 2023; 14:1308604. [PMID: 38169965 PMCID: PMC10758461 DOI: 10.3389/fendo.2023.1308604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 11/27/2023] [Indexed: 01/05/2024] Open
Abstract
Introduction Bioassembly techniques for the application of scaffold-free tissue engineering approaches have evolved in recent years toward producing larger tissue equivalents that structurally and functionally mimic native tissues. This study aims to upscale a 3-dimensional bone in-vitro model through bioassembly of differentiated rat osteoblast (dROb) spheroids with the potential to develop and mature into a bone macrotissue. Methods dROb spheroids in control and mineralization media at different seeding densities (1 × 104, 5 × 104, and 1 × 105 cells) were assessed for cell proliferation and viability by trypan blue staining, for necrotic core by hematoxylin and eosin staining, and for extracellular calcium by Alizarin red and Von Kossa staining. Then, a novel approach was developed to bioassemble dROb spheroids in pillar array supports using a customized bioassembly system. Pillar array supports were custom-designed and printed using Formlabs Clear Resin® by Formlabs Form2 printer. These supports were used as temporary frameworks for spheroid bioassembly until fusion occurred. Supports were then removed to allow scaffold-free growth and maturation of fused spheroids. Morphological and molecular analyses were performed to understand their structural and functional aspects. Results Spheroids of all seeding densities proliferated till day 14, and mineralization began with the cessation of proliferation. Necrotic core size increased over time with increased spheroid size. After the bioassembly of spheroids, the morphological assessment revealed the fusion of spheroids over time into a single macrotissue of more than 2.5 mm in size with mineral formation. Molecular assessment at different time points revealed osteogenic maturation based on the presence of osteocalcin, downregulation of Runx2 (p < 0.001), and upregulated alkaline phosphatase (p < 0.01). Discussion With the novel bioassembly approach used here, 3D bone macrotissues were successfully fabricated which mimicked physiological osteogenesis both morphologically and molecularly. This biofabrication approach has potential applications in bone tissue engineering, contributing to research related to osteoporosis and other recurrent bone ailments.
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Affiliation(s)
- Vinothini Prabhakaran
- Anatomy@Edinburgh, Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Discovery Brain Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Ferry P.W. Melchels
- School of Engineering and Physical Sciences, Institute of Biological Chemistry, Biophysics and Bioengineering, Heriot-Watt University, Edinburgh, United Kingdom
- Future Industries Institute, University of South Australia, Adelaide, SA, Australia
| | - Lyndsay M. Murray
- Anatomy@Edinburgh, Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Discovery Brain Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
- Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Jennifer Z. Paxton
- Anatomy@Edinburgh, Edinburgh Medical School, Biomedical Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Discovery Brain Sciences, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
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Kordala AJ, Stoodley J, Ahlskog N, Hanifi M, Garcia Guerra A, Bhomra A, Lim WF, Murray LM, Talbot K, Hammond SM, Wood MJA, Rinaldi C. PRMT inhibitor promotes SMN2 exon 7 inclusion and synergizes with nusinersen to rescue SMA mice. EMBO Mol Med 2023; 15:e17683. [PMID: 37724723 PMCID: PMC10630883 DOI: 10.15252/emmm.202317683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 08/31/2023] [Accepted: 09/01/2023] [Indexed: 09/21/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a leading genetic cause of infant mortality. The advent of approved treatments for this devastating condition has significantly changed SMA patients' life expectancy and quality of life. Nevertheless, these are not without limitations, and research efforts are underway to develop new approaches for improved and long-lasting benefits for patients. Protein arginine methyltransferases (PRMTs) are emerging as druggable epigenetic targets, with several small-molecule PRMT inhibitors already in clinical trials. From a screen of epigenetic molecules, we have identified MS023, a potent and selective type I PRMT inhibitor able to promote SMN2 exon 7 inclusion in preclinical SMA models. Treatment of SMA mice with MS023 results in amelioration of the disease phenotype, with strong synergistic amplification of the positive effect when delivered in combination with the antisense oligonucleotide nusinersen. Moreover, transcriptomic analysis revealed that MS023 treatment has minimal off-target effects, and the added benefit is mainly due to targeting neuroinflammation. Our study warrants further clinical investigation of PRMT inhibition both as a stand-alone and add-on therapy for SMA.
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Affiliation(s)
- Anna J Kordala
- Department of Physiology Anatomy and GeneticsUniversity of OxfordOxfordUK
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Jessica Stoodley
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Nina Ahlskog
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | | | - Antonio Garcia Guerra
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Amarjit Bhomra
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Wooi Fang Lim
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
| | - Lyndsay M Murray
- Centre for Discovery Brain Sciences, College of Medicine and Veterinary MedicineUniversity of EdinburghEdinburghUK
- Euan McDonald Centre for Motor Neuron Disease ResearchUniversity of EdinburghEdinburghUK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, John Radcliffe HospitalUniversity of OxfordOxfordUK
- Kavli Institute for Nanoscience DiscoveryUniversity of OxfordOxfordUK
| | | | - Matthew JA Wood
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
- MDUK Oxford Neuromuscular CentreOxfordUK
| | - Carlo Rinaldi
- Department of PaediatricsUniversity of OxfordOxfordUK
- Institute of Developmental and Regenerative Medicine (IDRM)OxfordUK
- MDUK Oxford Neuromuscular CentreOxfordUK
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Woschitz V, Mei I, Hedlund E, Murray LM. Mouse models of SMA show divergent patterns of neuronal vulnerability and resilience. Skelet Muscle 2022; 12:22. [PMID: 36089582 PMCID: PMC9465884 DOI: 10.1186/s13395-022-00305-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 08/24/2022] [Indexed: 11/21/2022] Open
Abstract
Background Spinal muscular atrophy (SMA) is a form of motor neuron disease affecting primarily children characterised by the loss of lower motor neurons (MNs). Breakdown of the neuromuscular junctions (NMJs) is an early pathological event in SMA. However, not all motor neurons are equally vulnerable, with some populations being lost early in the disease while others remain intact at the disease end-stage. A thorough understanding of the basis of this selective vulnerability will give critical insight into the factors which prohibit pathology in certain motor neuron populations and consequently help identify novel neuroprotective strategies. Methods To retrieve a comprehensive understanding of motor neuron susceptibility in SMA, we mapped NMJ pathology in 20 muscles from the Smn2B/- SMA mouse model and cross-compared these data with published data from three other commonly used mouse models. To gain insight into the molecular mechanisms regulating selective resilience and vulnerability, we analysed published RNA sequencing data acquired from differentially vulnerable motor neurons from two different SMA mouse models. Results In the Smn2B/- mouse model of SMA, we identified substantial NMJ loss in the muscles from the core, neck, proximal hind limbs and proximal forelimbs, with a marked reduction in denervation in the distal limbs and head. Motor neuron cell body loss was greater at T5 and T11 compared with L5. We subsequently show that although widespread denervation is observed in each SMA mouse model (with the notable exception of the Taiwanese model), all models have a distinct pattern of selective vulnerability. A comparison of previously published data sets reveals novel transcripts upregulated with a disease in selectively resistant motor neurons, including genes involved in axonal transport, RNA processing and mitochondrial bioenergetics. Conclusions Our work demonstrates that the Smn2B/- mouse model shows a pattern of selective vulnerability which bears resemblance to the regional pathology observed in SMA patients. We found drastic differences in patterns of selective vulnerability across the four SMA mouse models, which is critical to consider during experimental design. We also identified transcript groups that potentially contribute to the protection of certain motor neurons in SMA mouse models. Supplementary Information The online version contains supplementary material available at 10.1186/s13395-022-00305-9.
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Comley LH, Kline RA, Thomson AK, Woschitz V, Landeros EV, Osman EY, Lorson CL, Murray LM. OUP accepted manuscript. Hum Mol Genet 2022; 31:3107-3119. [PMID: 35551393 PMCID: PMC9476628 DOI: 10.1093/hmg/ddac097] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/19/2022] [Accepted: 04/23/2022] [Indexed: 11/14/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a childhood motor neuron disease caused by anomalies in the SMN1 gene. Although therapeutics have been approved for the treatment of SMA, there is a therapeutic time window, after which efficacy is reduced. Hallmarks of motor unit pathology in SMA include loss of motor-neurons and neuromuscular junction (NMJs). Following an increase in Smn levels, it is unclear how much damage can be repaired and the degree to which normal connections are re-established. Here, we perform a detailed analysis of motor unit pathology before and after restoration of Smn levels. Using a Smn-inducible mouse model of SMA, we show that genetic restoration of Smn results in a dramatic reduction in NMJ pathology, with restoration of innervation patterns, preservation of axon and endplate number and normalized expression of P53-associated transcripts. Notably, presynaptic swelling and elevated Pmaip levels remained. We analysed the effect of either early or delayed treated of an antisense oligonucleotide (ASO) targeting SMN2 on a range of differentially vulnerable muscles. Following ASO administration, the majority of endplates appeared fully occupied. However, there was an underlying loss of axons and endplates, which was more prevalent following a delay in treatment. There was an increase in average motor unit size following both early and delayed treatment. Together this work demonstrates the remarkably regenerative capacity of the motor neuron following Smn restoration, but highlights that recovery is incomplete. This work suggests that there is an opportunity to enhance neuromuscular junction recovery following administration of Smn-enhancing therapeutics.
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Affiliation(s)
- Laura H Comley
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Rachel A Kline
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Alison K Thomson
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Victoria Woschitz
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, EH8 9XD, UK
- Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, EH16 4SB, UK
| | - Eric Villalón Landeros
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205-2185, USA
| | - Erkan Y Osman
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Christian L Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Lyndsay M Murray
- To whom correspondence should be addressed at: College of Medicine and Veterinary Medicine, University of Edinburgh, Old Medical School, Teviot Place, Edinburgh EH8 9XD, UK. Tel: +44 131 651 5985;
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Villalón E, Kline RA, Smith CE, Lorson ZC, Osman EY, O'Day S, Murray LM, Lorson CL. AAV9-Stathmin1 gene delivery improves disease phenotype in an intermediate mouse model of spinal muscular atrophy. Hum Mol Genet 2020; 28:3742-3754. [PMID: 31363739 DOI: 10.1093/hmg/ddz188] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/12/2019] [Accepted: 07/23/2019] [Indexed: 02/06/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a devastating infantile genetic disorder caused by the loss of survival motor neuron (SMN) protein that leads to premature death due to loss of motor neurons and muscle atrophy. The approval of an antisense oligonucleotide therapy for SMA was an important milestone in SMA research; however, effective next-generation therapeutics will likely require combinatorial SMN-dependent therapeutics and SMN-independent disease modifiers. A recent cross-disease transcriptomic analysis identified Stathmin-1 (STMN1), a tubulin-depolymerizing protein, as a potential disease modifier across different motor neuron diseases, including SMA. Here, we investigated whether viral-based delivery of STMN1 decreased disease severity in a well-characterized SMA mouse model. Intracerebroventricular delivery of scAAV9-STMN1 in SMA mice at P2 significantly increased survival and weight gain compared to untreated SMA mice without elevating Smn levels. scAAV9-STMN1 improved important hallmarks of disease, including motor function, NMJ pathology and motor neuron cell preservation. Furthermore, scAAV9-STMN1 treatment restored microtubule networks and tubulin expression without affecting tubulin stability. Our results show that scAAV9-STMN1 treatment improves SMA pathology possibly by increasing microtubule turnover leading to restored levels of stable microtubules. Overall, these data demonstrate that STMN1 can significantly reduce the SMA phenotype independent of restoring SMN protein and highlight the importance of developing SMN-independent therapeutics for the treatment of SMA.
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Affiliation(s)
- E Villalón
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - R A Kline
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - C E Smith
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Z C Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - E Y Osman
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - S O'Day
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - L M Murray
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, UK
- Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, UK
| | - C L Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
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Mole AJ, Bell S, Thomson AK, Dissanayake KN, Ribchester RR, Murray LM. Synaptic withdrawal following nerve injury is influenced by postnatal maturity, muscle-specific properties, and the presence of underlying pathology in mice. J Anat 2020; 237:263-274. [PMID: 32311115 PMCID: PMC7369188 DOI: 10.1111/joa.13187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/30/2020] [Accepted: 03/02/2020] [Indexed: 01/13/2023] Open
Abstract
Axonal and synaptic degeneration occur following nerve injury and during disease. Traumatic nerve injury results in rapid fragmentation of the distal axon and loss of synaptic terminals, in a process known as Wallerian degeneration (WD). Identifying and understanding factors that influence the rate of WD is of significant biological and clinical importance, as it will facilitate understanding of the mechanisms of neurodegeneration and identification of novel therapeutic targets. Here, we investigate levels of synaptic loss following nerve injury under a range of conditions, including during postnatal development, in a range of anatomically distinct muscles and in a mouse model of motor neuron disease. By utilising an ex vivo model of nerve injury, we show that synaptic withdrawal is slower during early postnatal development. Significantly more neuromuscular junctions remained fully innervated in the cranial nerve/muscle preparations analysed at P15 than at P25. Furthermore, we demonstrate variability in the level of synaptic withdrawal in response to injury in different muscles, with retraction being slower in abdominal preparations than in cranial muscles across all time points analysed. Importantly, differences between the cranial and thoracoabdominal musculature seen here are not consistent with differences in muscle vulnerability that have been previously reported in mouse models of the childhood motor neuron disease, spinal muscular atrophy (SMA), caused by depletion of survival motor neuron protein (Smn). To further investigate the relationship between synaptic degeneration in SMA and WD, we induced WD in preparations from the Smn2B/− mouse model of SMA. In a disease‐resistant muscle (rostral band of levator auris longus), where there is minimal denervation, there was no change in the level of synaptic loss, which suggests that the process of synaptic withdrawal following injury is Smn‐independent. However, in a muscle with ongoing degeneration (transvs. abdominis), the level of synaptic loss significantly increased, with the percentage of denervated endplates increasing by 33% following injury, compared to disease alone. We therefore conclude that the presence of a die‐back can accelerate synaptic loss after injury in Smn2B/− mice.
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Affiliation(s)
- Alannah J Mole
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Sarah Bell
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Alison K Thomson
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Kosala N Dissanayake
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Richard R Ribchester
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
| | - Lyndsay M Murray
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, UK.,The Euan MacDonald Centre for Motor Neurone Disease Research, Edinburgh, UK
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Abstract
Abstract
A trend to market-driven health care in many parts of the world is focusing increasing attention on getting maximum value from available resources. Laboratories are not exempted. Well-informed clinical input has a potentially valuable role in any laboratory rationalization process. However, a communication difficulty exists in the sense that, although laboratory workers, commercial developers, regulatory bodies, etc., are thoroughly conditioned to using assay coefficient of variation as a general performance measure (for excellent reasons), this is not necessarily the most intuitive or informative scale from a clinician's perspective. Here we use routine clinical data from an immunoradiometric assay of thyrotropin to illustrate, first, a general approach to estimation and prediction of reproducibility, and second, an alternative summary that expresses the discriminatory power of an assay. This latter measure, our experience suggests, is more suited to the way clinicians perceive assays and assay results. The overall aim is improved clinician/laboratory communication.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
| | - L M Murray
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
| | - J G Turner
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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Deguise M, Baranello G, Mastella C, Beauvais A, Michaud J, Leone A, De Amicis R, Battezzati A, Dunham C, Selby K, Warman Chardon J, McMillan HJ, Huang Y, Courtney NL, Mole AJ, Kubinski S, Claus P, Murray LM, Bowerman M, Gillingwater TH, Bertoli S, Parson SH, Kothary R. Abnormal fatty acid metabolism is a core component of spinal muscular atrophy. Ann Clin Transl Neurol 2019; 6:1519-1532. [PMID: 31402618 PMCID: PMC6689695 DOI: 10.1002/acn3.50855] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 07/09/2019] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Spinal muscular atrophy (SMA) is an inherited neuromuscular disorder leading to paralysis and subsequent death in young children. Initially considered a motor neuron disease, extra-neuronal involvement is increasingly recognized. The primary goal of this study was to investigate alterations in lipid metabolism in SMA patients and mouse models of the disease. METHODS We analyzed clinical data collected from a large cohort of pediatric SMA type I-III patients as well as SMA type I liver necropsy data. In parallel, we performed histology, lipid analysis, and transcript profiling in mouse models of SMA. RESULTS We identify an increased susceptibility to developing dyslipidemia in a cohort of 72 SMA patients and liver steatosis in pathological samples. Similarly, fatty acid metabolic abnormalities were present in all SMA mouse models studied. Specifically, Smn2B/- mice displayed elevated hepatic triglycerides and dyslipidemia, resembling non-alcoholic fatty liver disease (NAFLD). Interestingly, this phenotype appeared prior to denervation. INTERPRETATION This work highlights metabolic abnormalities as an important feature of SMA, suggesting implementation of nutritional and screening guidelines in patients, as such defects are likely to increase metabolic distress and cardiovascular risk. This study emphasizes the need for a systemic therapeutic approach to ensure maximal benefits for all SMA patients throughout their life.
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Affiliation(s)
- Marc‐Olivier Deguise
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Centre for Neuromuscular DiseaseUniversity of OttawaOttawaOntarioCanadaK1H 8M5
| | - Giovanni Baranello
- UO Neurologia dello SviluppoFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
- The Dubowitz Neuromuscular CentreNIHR BRC University College London Great Ormond Street Institute of Child Health & Great Ormond Street HospitalLondonUnited Kingdom
| | - Chiara Mastella
- SAPRE‐UONPIA, Fondazione IRCCS Cà' Granda Ospedale Maggiore PoliclinicoMilanItaly
| | - Ariane Beauvais
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
| | - Jean Michaud
- Department of Pathology and Laboratory Medicine, Faculty of MedicineUniversity of OttawaOttawaOntarioCanada
| | - Alessandro Leone
- International Center for the Assessment of Nutritional Status (ICANS), Department of Food, Environmental and Nutritional Sciences (DeFENS)University of MilanMilanItaly
| | - Ramona De Amicis
- International Center for the Assessment of Nutritional Status (ICANS), Department of Food, Environmental and Nutritional Sciences (DeFENS)University of MilanMilanItaly
| | - Alberto Battezzati
- International Center for the Assessment of Nutritional Status (ICANS), Department of Food, Environmental and Nutritional Sciences (DeFENS)University of MilanMilanItaly
| | - Christopher Dunham
- Division of Anatomic PathologyChildren's and Women's Health Centre of B.CVancouverBritish ColumbiaCanada
| | - Kathryn Selby
- Division of Neurology, Department of PediatricsBC Children's HospitalVancouverBritish ColumbiaCanada
| | - Jodi Warman Chardon
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Centre for Neuromuscular DiseaseUniversity of OttawaOttawaOntarioCanadaK1H 8M5
- Neuroscience Program, Ottawa Hospital Research InstituteOttawaOntarioCanada
- Department of PediatricsChildren's Hospital of Eastern OntarioOttawaOntarioCanada
- Department of MedicineUniversity of OttawaOttawaOntarioCanada
| | - Hugh J. McMillan
- Children's Hospital of Eastern Ontario Research InstituteUniversity of OttawaOttawaOntarioCanada
| | - Yu‐Ting Huang
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
| | - Natalie L. Courtney
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
- Centre for Discovery Brain ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Alannah J. Mole
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
- Centre for Discovery Brain ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Sabrina Kubinski
- Institute of Neuroanatomy and Cell BiologyHannover Medical SchoolHannoverGermany
- Center of Systems NeuroscienceHannoverGermany
| | - Peter Claus
- Institute of Neuroanatomy and Cell BiologyHannover Medical SchoolHannoverGermany
- Center of Systems NeuroscienceHannoverGermany
| | - Lyndsay M. Murray
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
- Centre for Discovery Brain ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Melissa Bowerman
- School of MedicineKeele UniversityStaffordshireUnited Kingdom
- Institute for Science and Technology in MedicineStoke‐on‐TrentUnited Kingdom
- Wolfson Centre for Inherited Neuromuscular DiseaseRJAH Orthopaedic HospitalOswestryUnited Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- College of Medicine & Veterinary MedicineUniversity of EdinburghEdinburghUnited Kingdom
| | - Simona Bertoli
- International Center for the Assessment of Nutritional Status (ICANS), Department of Food, Environmental and Nutritional Sciences (DeFENS)University of MilanMilanItaly
| | - Simon H. Parson
- Euan MacDonald Centre for Motor Neurone Disease ResearchUniversity of EdinburghEdinburghUnited Kingdom
- Institute of Medical SciencesUniversity of AberdeenAberdeenUnited Kingdom
| | - Rashmi Kothary
- Regenerative Medicine ProgramOttawa Hospital Research InstituteOttawaOntarioCanada
- Department of Cellular and Molecular MedicineUniversity of OttawaOttawaOntarioCanada
- Centre for Neuromuscular DiseaseUniversity of OttawaOttawaOntarioCanadaK1H 8M5
- Department of MedicineUniversity of OttawaOttawaOntarioCanada
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Courtney NL, Mole AJ, Thomson AK, Murray LM. Reduced P53 levels ameliorate neuromuscular junction loss without affecting motor neuron pathology in a mouse model of spinal muscular atrophy. Cell Death Dis 2019; 10:515. [PMID: 31273192 PMCID: PMC6609617 DOI: 10.1038/s41419-019-1727-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 04/23/2019] [Accepted: 05/28/2019] [Indexed: 11/09/2022]
Abstract
Spinal Muscular Atrophy (SMA) is a childhood motor neuron disease caused by mutations or deletions within the SMN1 gene. At endstages of disease there is profound loss of motor neurons, loss of axons within ventral roots and defects at the neuromuscular junctions (NMJ), as evidenced by pathological features such as pre-synaptic loss and swelling and post-synaptic shrinkage. Although these motor unit defects have been widely described, the time course and interdependancy of these aspects of motor unit degeneration are unclear. Recent reports have also revealed an early upregulation of transcripts associated with the P53 signalling pathway. The relationship between the upregulation of these transcripts and pathology within the motor unit is also unclear. In this study, we exploit the prolonged disease timecourse and defined pre-symptomatic period in the Smn2B/- mouse model to perform a temporal analysis of the different elements of motor unit pathology. We demonstrate that NMJ loss occurs prior to cell body loss, and coincides with the onset of symptoms. The onset of NMJ pathology also coincides with an increase in P53-related transcripts at the cell body. Finally, using a tamoxifen inducible P53 knockout, we demonstrate that post-natal reduction in P53 levels can reduce NMJ loss, but does not affect other aspects of NMJ pathology, motor neuron loss or the phenotype of the Smn2B/- mouse model. Together this work provides a detailed temporal description of pathology within motor units of an SMA mouse model, and demonstrates that NMJ loss is a P53-dependant process. This work supports the role for P53 as an effector of synaptic and axonal degeneration in a die-back neuropathy.
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Affiliation(s)
- Natalie L Courtney
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, Edinburgh, UK.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Scotland, EH8 9XD, UK
| | - Alannah J Mole
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, Edinburgh, UK.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Scotland, EH8 9XD, UK
| | - Alison K Thomson
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, Edinburgh, UK.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Scotland, EH8 9XD, UK
| | - Lyndsay M Murray
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, Edinburgh, UK. .,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Scotland, EH8 9XD, UK.
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10
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Groen EJN, Perenthaler E, Courtney NL, Jordan CY, Shorrock HK, van der Hoorn D, Huang YT, Murray LM, Viero G, Gillingwater TH. Temporal and tissue-specific variability of SMN protein levels in mouse models of spinal muscular atrophy. Hum Mol Genet 2019; 27:2851-2862. [PMID: 29790918 PMCID: PMC6077828 DOI: 10.1093/hmg/ddy195] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 05/14/2018] [Indexed: 02/02/2023] Open
Abstract
Spinal muscular atrophy (SMA) is a progressive motor neuron disease caused by deleterious variants in SMN1 that lead to a marked decrease in survival motor neuron (SMN) protein expression. Humans have a second SMN gene (SMN2) that is almost identical to SMN1. However, due to alternative splicing the majority of SMN2 messenger ribonucleic acid (mRNA) is translated into a truncated, unstable protein that is quickly degraded. Because the presence of SMN2 provides a unique opportunity for therapy development in SMA patients, the mechanisms that regulate SMN2 splicing and mRNA expression have been elucidated in great detail. In contrast, how much SMN protein is produced at different developmental time points and in different tissues remains under-characterized. In this study, we addressed this issue by determining SMN protein expression levels at three developmental time points across six different mouse tissues and in two distinct mouse models of SMA (‘severe’ Taiwanese and ‘intermediate’ Smn2B/− mice). We found that, in healthy control mice, SMN protein expression was significantly influenced by both age and tissue type. When comparing mouse models of SMA, we found that, despite being transcribed from genetically different alleles, control SMN levels were relatively similar. In contrast, the degree of SMN depletion between tissues in SMA varied substantially over time and between the two models. These findings offer an explanation for the differential vulnerability of tissues and organs observed in SMA and further our understanding of the systemic and temporal requirements for SMN with direct relevance for developing effective therapies for SMA.
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Affiliation(s)
- Ewout J N Groen
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Elena Perenthaler
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Natalie L Courtney
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Crispin Y Jordan
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences
| | - Hannah K Shorrock
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Dinja van der Hoorn
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Yu-Ting Huang
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Lyndsay M Murray
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Gabriella Viero
- Institute of Biophysics, CNR Unit at Trento, 38123 Povo, Trento, Italy
| | - Thomas H Gillingwater
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences.,Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh EH8 9XD, UK
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11
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Walter LM, Deguise MO, Meijboom KE, Betts CA, Ahlskog N, van Westering TLE, Hazell G, McFall E, Kordala A, Hammond SM, Abendroth F, Murray LM, Shorrock HK, Prosdocimo DA, Haldar SM, Jain MK, Gillingwater TH, Claus P, Kothary R, Wood MJA, Bowerman M. Interventions Targeting Glucocorticoid-Krüppel-like Factor 15-Branched-Chain Amino Acid Signaling Improve Disease Phenotypes in Spinal Muscular Atrophy Mice. EBioMedicine 2018; 31:226-242. [PMID: 29735415 PMCID: PMC6013932 DOI: 10.1016/j.ebiom.2018.04.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 04/15/2018] [Accepted: 04/26/2018] [Indexed: 01/01/2023] Open
Abstract
The circadian glucocorticoid-Krüppel-like factor 15-branched-chain amino acid (GC-KLF15-BCAA) signaling pathway is a key regulatory axis in muscle, whose imbalance has wide-reaching effects on metabolic homeostasis. Spinal muscular atrophy (SMA) is a neuromuscular disorder also characterized by intrinsic muscle pathologies, metabolic abnormalities and disrupted sleep patterns, which can influence or be influenced by circadian regulatory networks that control behavioral and metabolic rhythms. We therefore set out to investigate the contribution of the GC-KLF15-BCAA pathway in SMA pathophysiology of Taiwanese Smn−/−;SMN2 and Smn2B/− mouse models. We thus uncover substantial dysregulation of GC-KLF15-BCAA diurnal rhythmicity in serum, skeletal muscle and metabolic tissues of SMA mice. Importantly, modulating the components of the GC-KLF15-BCAA pathway via pharmacological (prednisolone), genetic (muscle-specific Klf15 overexpression) and dietary (BCAA supplementation) interventions significantly improves disease phenotypes in SMA mice. Our study highlights the GC-KLF15-BCAA pathway as a contributor to SMA pathogenesis and provides several treatment avenues to alleviate peripheral manifestations of the disease. The therapeutic potential of targeting metabolic perturbations by diet and commercially available drugs could have a broader implementation across other neuromuscular and metabolic disorders characterized by altered GC-KLF15-BCAA signaling. SMA is a neuromuscular disease characterized by motoneuron loss, muscle abnormalities and metabolic perturbations. The regulatory GC-KLF15-BCAA pathway is dysregulated in serum and skeletal muscle of SMA mice during disease progression. Modulating GC-KLF15-BCAA signaling by pharmacological, dietary and genetic interventions improves phenotype of SMA mice.
Spinal muscular atrophy (SMA) is a devastating and debilitating childhood genetic disease. Although nerve cells are mainly affected, muscle is also severely impacted. The normal communication between the glucocorticoid (GC) hormone, the protein KLF15 and the dietary branched-chain amino acids (BCAAs) maintains muscle and whole-body health. In this study, we identified an abnormal activity of GC-KLF15- BCAA in blood and muscle of SMA mice. Importantly, targeting GC-KLF15-BCAA activity with an existing drug or a specific diet improved disease progression in SMA mice. Our research uncovers GCs, KLF15 and BCAAs as therapeutic targets to ameliorate SMA muscle and whole-body health.
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Affiliation(s)
- Lisa M Walter
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany; Center of Systems Neuroscience, Hannover, Germany
| | - Marc-Olivier Deguise
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada; Department of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Katharina E Meijboom
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Corinne A Betts
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Nina Ahlskog
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Tirsa L E van Westering
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Gareth Hazell
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Emily McFall
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada; Department of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Anna Kordala
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Suzan M Hammond
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Frank Abendroth
- Medical Research Council, Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Lyndsay M Murray
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Hannah K Shorrock
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Domenick A Prosdocimo
- Case Cardiovascular Research Institute, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, OH, USA
| | - Saptarsi M Haldar
- Gladstone Institute of Cardiovascular Disease, San Francisco, CA, USA; Department of Medicine, Division of Cardiology University of California, San Francisco, CA, USA
| | - Mukesh K Jain
- Case Cardiovascular Research Institute, Case Western Reserve University School of Medicine, University Hospitals Case Medical Center, Cleveland, OH, USA
| | - Thomas H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom; Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter Claus
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Hannover, Germany; Center of Systems Neuroscience, Hannover, Germany
| | - Rashmi Kothary
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada; Department of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Melissa Bowerman
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
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12
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Bowerman M, Murray LM, Scamps F, Schneider BL, Kothary R, Raoul C. Pathogenic commonalities between spinal muscular atrophy and amyotrophic lateral sclerosis: Converging roads to therapeutic development. Eur J Med Genet 2017; 61:685-698. [PMID: 29313812 DOI: 10.1016/j.ejmg.2017.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Revised: 10/04/2017] [Accepted: 12/03/2017] [Indexed: 12/12/2022]
Abstract
Spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS) are the two most common motoneuron disorders, which share typical pathological hallmarks while remaining genetically distinct. Indeed, SMA is caused by deletions or mutations in the survival motor neuron 1 (SMN1) gene whilst ALS, albeit being mostly sporadic, can also be caused by mutations within genes, including superoxide dismutase 1 (SOD1), Fused in Sarcoma (FUS), TAR DNA-binding protein 43 (TDP-43) and chromosome 9 open reading frame 72 (C9ORF72). However, it has come to light that these two diseases may be more interlinked than previously thought. Indeed, it has recently been found that FUS directly interacts with an Smn-containing complex, mutant SOD1 perturbs Smn localization, Smn depletion aggravates disease progression of ALS mice, overexpression of SMN in ALS mice significantly improves their phenotype and lifespan, and duplications of SMN1 have been linked to sporadic ALS. Beyond genetic interactions, accumulating evidence further suggests that both diseases share common pathological identities such as intrinsic muscle defects, neuroinflammation, immune organ dysfunction, metabolic perturbations, defects in neuron excitability and selective motoneuron vulnerability. Identifying common molecular effectors that mediate shared pathologies in SMA and ALS would allow for the development of therapeutic strategies and targeted gene therapies that could potentially alleviate symptoms and be equally beneficial in both disorders. In the present review, we will examine our current knowledge of pathogenic commonalities between SMA and ALS, and discuss how furthering this understanding can lead to the establishment of novel therapeutic approaches with wide-reaching impact on multiple motoneuron diseases.
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Affiliation(s)
- Melissa Bowerman
- School of Medicine, Keele University, Staffordshire, United Kingdom; Institute for Science and Technology in Medicine, Stoke-on-Trent, United Kingdom; Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, United Kingdom
| | - Lyndsay M Murray
- Euan McDonald Centre for Motor Neuron Disease Research and Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Frédérique Scamps
- The Institute for Neurosciences of Montpellier, Inserm UMR1051, Univ Montpellier, Saint Eloi Hospital, Montpellier, France
| | - Bernard L Schneider
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada; Departments of Medicine and Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Cédric Raoul
- The Institute for Neurosciences of Montpellier, Inserm UMR1051, Univ Montpellier, Saint Eloi Hospital, Montpellier, France.
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13
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Hall EA, Nahorski MS, Murray LM, Shaheen R, Perkins E, Dissanayake KN, Kristaryanto Y, Jones RA, Vogt J, Rivagorda M, Handley MT, Mali GR, Quidwai T, Soares DC, Keighren MA, McKie L, Mort RL, Gammoh N, Garcia-Munoz A, Davey T, Vermeren M, Walsh D, Budd P, Aligianis IA, Faqeih E, Quigley AJ, Jackson IJ, Kulathu Y, Jackson M, Ribchester RR, von Kriegsheim A, Alkuraya FS, Woods CG, Maher ER, Mill P. PLAA Mutations Cause a Lethal Infantile Epileptic Encephalopathy by Disrupting Ubiquitin-Mediated Endolysosomal Degradation of Synaptic Proteins. Am J Hum Genet 2017; 100:706-724. [PMID: 28413018 PMCID: PMC5420347 DOI: 10.1016/j.ajhg.2017.03.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Accepted: 03/17/2017] [Indexed: 12/12/2022] Open
Abstract
During neurotransmission, synaptic vesicles undergo multiple rounds of exo-endocytosis, involving recycling and/or degradation of synaptic proteins. While ubiquitin signaling at synapses is essential for neural function, it has been assumed that synaptic proteostasis requires the ubiquitin-proteasome system (UPS). We demonstrate here that turnover of synaptic membrane proteins via the endolysosomal pathway is essential for synaptic function. In both human and mouse, hypomorphic mutations in the ubiquitin adaptor protein PLAA cause an infantile-lethal neurodysfunction syndrome with seizures. Resulting from perturbed endolysosomal degradation, Plaa mutant neurons accumulate K63-polyubiquitylated proteins and synaptic membrane proteins, disrupting synaptic vesicle recycling and neurotransmission. Through characterization of this neurological intracellular trafficking disorder, we establish the importance of ubiquitin-mediated endolysosomal trafficking at the synapse.
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Affiliation(s)
- Emma A Hall
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Michael S Nahorski
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, UK; Department of Medical Genetics, University of Cambridge, and Cambridge NIHR Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge CB2 OXY, UK
| | - Lyndsay M Murray
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK; Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Ranad Shaheen
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia
| | - Emma Perkins
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK; Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Kosala N Dissanayake
- Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK; Patrick Wild Centre, University of Edinburgh, Edinburgh EH8 9XD, UK; Centre for Cognitive and Neural Systems, University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - Yosua Kristaryanto
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee DD1 5EH, UK
| | - Ross A Jones
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK; Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Julie Vogt
- West Midlands Regional Genetics Service, Clinical Genetics Unit, Birmingham Women's Hospital, Birmingham B15 2TG, UK
| | - Manon Rivagorda
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Mark T Handley
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Girish R Mali
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Tooba Quidwai
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Dinesh C Soares
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK; Centre for Genomic and Experimental Medicine, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Margaret A Keighren
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Lisa McKie
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Richard L Mort
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Noor Gammoh
- Edinburgh Cancer Research UK Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | | | - Tracey Davey
- Electron Microscopy Research Services, Newcastle University, Newcastle NE2 4HH, UK
| | - Matthieu Vermeren
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Diana Walsh
- West Midlands Regional Genetics Service, Clinical Genetics Unit, Birmingham Women's Hospital, Birmingham B15 2TG, UK
| | - Peter Budd
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Irene A Aligianis
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Eissa Faqeih
- Department of Pediatric Subspecialties, Children's Hospital, King Fahad Medical City, Riyadh 11211, Saudi Arabia
| | - Alan J Quigley
- NHS Lothian, Department of Paediatric Radiology, Royal Hospital for Sick Children, Edinburgh EH9 1LF, UK
| | - Ian J Jackson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - Yogesh Kulathu
- MRC Protein Phosphorylation and Ubiquitylation Unit, University of Dundee, Dundee DD1 5EH, UK
| | - Mandy Jackson
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK; Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Richard R Ribchester
- Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh EH16 4SB, UK; Patrick Wild Centre, University of Edinburgh, Edinburgh EH8 9XD, UK; Centre for Cognitive and Neural Systems, University of Edinburgh, Edinburgh EH8 9JZ, UK
| | - Alex von Kriegsheim
- Edinburgh Cancer Research UK Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK; Systems Biology Ireland, University College Dublin, Dublin, Ireland
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh 11211, Saudi Arabia; Department of Anatomy and Cell Biology, College of Medicine, Alfaisal University, Riyadh 11533, Saudi Arabia; Saudi Human Genome Program, King Abdulaziz City for Science and Technology, Riyadh 11442, Saudi Arabia
| | - C Geoffrey Woods
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 OXY, UK; Department of Medical Genetics, University of Cambridge, and Cambridge NIHR Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge CB2 OXY, UK
| | - Eamonn R Maher
- Department of Medical Genetics, University of Cambridge, and Cambridge NIHR Biomedical Research Centre, Cambridge Biomedical Campus, Cambridge CB2 OXY, UK.
| | - Pleasantine Mill
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK.
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Kline RA, Kaifer KA, Osman EY, Carella F, Tiberi A, Ross J, Pennetta G, Lorson CL, Murray LM. Comparison of independent screens on differentially vulnerable motor neurons reveals alpha-synuclein as a common modifier in motor neuron diseases. PLoS Genet 2017; 13:e1006680. [PMID: 28362802 PMCID: PMC5391970 DOI: 10.1371/journal.pgen.1006680] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 04/14/2017] [Accepted: 03/09/2017] [Indexed: 02/04/2023] Open
Abstract
The term “motor neuron disease” encompasses a spectrum of disorders in which motor neurons are the primary pathological target. However, in both patients and animal models of these diseases, not all motor neurons are equally vulnerable, in that while some motor neurons are lost very early in disease, others remain comparatively intact, even at late stages. This creates a valuable system to investigate the factors that regulate motor neuron vulnerability. In this study, we aim to use this experimental paradigm to identify potential transcriptional modifiers. We have compared the transcriptome of motor neurons from healthy wild-type mice, which are differentially vulnerable in the childhood motor neuron disease Spinal Muscular Atrophy (SMA), and have identified 910 transcriptional changes. We have compared this data set with published microarray data sets on other differentially vulnerable motor neurons. These neurons were differentially vulnerable in the adult onset motor neuron disease Amyotrophic Lateral Sclerosis (ALS), but the screen was performed on the equivalent population of neurons from neurologically normal human, rat and mouse. This cross species comparison has generated a refined list of differentially expressed genes, including CELF5, Col5a2, PGEMN1, SNCA, Stmn1 and HOXa5, alongside a further enrichment for synaptic and axonal transcripts. As an in vivo validation, we demonstrate that the manipulation of a significant number of these transcripts can modify the neurodegenerative phenotype observed in a Drosophila line carrying an ALS causing mutation. Finally, we demonstrate that vector-mediated expression of alpha-synuclein (SNCA), a transcript decreased in selectively vulnerable motor neurons in all four screens, can extend life span, increase weight and decrease neuromuscular junction pathology in a mouse model of SMA. In summary, we have combined multiple data sets to identify transcripts, which are strong candidates for being phenotypic modifiers, and demonstrated SNCA is a modifier of pathology in motor neuron disease. The term “motor neuron disease” refers to a group of disorders, causing progressive paralysis of affected patients due to the degeneration of motor neurons cells which control voluntary movements. Importantly, not all motor neurons appear to be affected in the same way, with those that control the face being affected less that those that control the abdomen. The reason why some motor neurons are more vulnerable is unknown; however, understanding this may provide new targets for therapeutics to slow motor neuron degeneration either as stand-alone therapeutics or in combination with SMN-inducing compounds. In this study, we analysed gene expression in different groups of motor neurons and compared this to previously published expression data to identify commonalities. One of the common transcripts was alpha-synuclein (SNCA), which was consistently expressed at lower levels in vulnerable motor neurons. Importantly, when SNCA levels were increased in a mouse model of motor neuron disease, the disease phenotype was significantly reduced, including an extension in survival and reduction in motor neuron pathology. Collectively, these results demonstrate that this approach can identify disease modifiers that can reduce disease severity in models of motor neuron disease and potentially identify new therapeutic targets.
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Affiliation(s)
- Rachel A. Kline
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
- Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Kevin A. Kaifer
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
| | - Erkan Y. Osman
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
| | - Francesco Carella
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
- Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Ariana Tiberi
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Jolill Ross
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
| | - Giuseppa Pennetta
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
- Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
| | - Christian L. Lorson
- Bond Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
| | - Lyndsay M. Murray
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
- Euan McDonald Centre for Motor Neuron Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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15
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Murray LM, Beauvais A, Gibeault S, Courtney NL, Kothary R. Transcriptional profiling of differentially vulnerable motor neurons at pre-symptomatic stage in the Smn (2b/-) mouse model of spinal muscular atrophy. Acta Neuropathol Commun 2015; 3:55. [PMID: 26374403 PMCID: PMC4570693 DOI: 10.1186/s40478-015-0231-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 08/10/2015] [Indexed: 12/17/2022] Open
Abstract
INTRODUCTION The term motor neuron disease encompasses a spectrum of disorders in which motor neurons are the lost. Importantly, while some motor neurons are lost early in disease and others remain intact at disease end-stage. This creates a valuable experimental paradigm to investigate the factors that regulate motor neuron vulnerability. Spinal muscular atrophy is a childhood motor neuron disease caused by mutations or deletions in the SMN1 gene. Here, we have performed transcriptional analysis on differentially vulnerable motor neurons from an intermediate mouse model of Spinal muscular atrophy at a presymptomatic time point. RESULTS We have characterised two differentially vulnerable populations, differing in the level neuromuscular junction loss. Transcriptional analysis on motor neuron cell bodies revealed that reduced Smn levels correlate with a reduction of transcripts associated with the ribosome, rRNA binding, ubiquitination and oxidative phosphorylation. Furthermore, P53 pathway activation precedes neuromuscular junction loss, suggesting that denervation may be a consequence, rather than a cause of motor neuron death in Spinal muscular atrophy. Finally, increased vulnerability correlates with a decrease in the positive regulation of DNA repair. CONCLUSIONS This study identifies pathways related to the function of Smn and associated with differential motor unit vulnerability, thus presenting a number of exciting targets for future therapeutic development.
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Abstract
Spinal muscular atrophy (SMA) is a devastating motor neuron disease primarily affecting children, for which there is currently no known disease-modifying therapy or cure. The identification of the disease gene, survival motor neuron, led to an expansion in SMA research and allowed the creation of numerous animal and cellular models. This led to a significant increase in our understanding of the pathophysiology of SMA, culminating in the development of multiple SMN-dependent and -independent therapies. Among the most exciting options, viral gene therapy has emerged as one leading candidate. A growing body of pre-clinical evidence suggests that administration of scAAV9 carrying an SMN transgene can be both efficacious and translationally viable. In this article, we briefly review the progress which has been made in the field, and provide a commentary on some of the challenges which remain.
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Affiliation(s)
- Thomas H Gillingwater
- a 1 Centre for Integrative Physiology, University of Edinburgh, EH8 9XD, Edinburgh, UK
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McFall ER, Murray LM, Lunde JA, Jasmin BJ, Kothary R, Parks RJ. A reduction in the human adenovirus virion size through use of a shortened fibre protein does not enhance muscle transduction following systemic or localised delivery in mice. Virology 2014; 468-470:444-453. [PMID: 25243333 DOI: 10.1016/j.virol.2014.08.026] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 07/28/2014] [Accepted: 08/22/2014] [Indexed: 02/06/2023]
Abstract
We have investigated whether reducing the overall size of adenovirus (Ad), through use of a vector containing a shortened fibre, leads to enhanced distribution and dissemination of the vector. Intravenous or intraperitoneal injection of Ad5SlacZ (12 nm fibre versus the normal Ad5 37 nm fibre) or Ad5SpKlacZ (shortened fibre with polylysine motif in the H-I loop of fibre knob domain) led to similar levels of lacZ expression compared to Ad5LlacZ (native Ad5 fibre) in the liver of treated animals, but did not enhance extravasation into the tibialis anterior muscle. Direct injection of the short-fibre vectors into the tibialis anterior muscle did not result in enhanced spread of the vector through muscle tissue, and led to only sporadic transgene expression in the spinal cord, suggesting that modifying the fibre length or redirecting viral infection to a more common cell surface receptor does not enhance motor neuron uptake or retrograde transport.
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Affiliation(s)
- Emily R McFall
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada
| | - Lyndsay M Murray
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6
| | - John A Lunde
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada; University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada
| | - Rashmi Kothary
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6; Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada; University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada; Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Robin J Parks
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada K1H 8L6; Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario, Canada; University of Ottawa Centre for Neuromuscular Disease, Ottawa, Ontario, Canada; Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
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Boyer JG, Deguise MO, Murray LM, Yazdani A, De Repentigny Y, Boudreau-Larivière C, Kothary R. Myogenic program dysregulation is contributory to disease pathogenesis in spinal muscular atrophy. Hum Mol Genet 2014; 23:4249-59. [PMID: 24691550 PMCID: PMC4103674 DOI: 10.1093/hmg/ddu142] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mutations in the survival motor neuron (SMN1) gene lead to the neuromuscular disease spinal muscular atrophy (SMA). Although SMA is primarily considered as a motor neuron disease, the importance of muscle defects in its pathogenesis has not been fully examined. We use both primary cell culture and two different SMA model mice to demonstrate that reduced levels of Smn lead to a profound disruption in the expression of myogenic genes. This disruption was associated with a decrease in myofiber size and an increase in immature myofibers, suggesting that Smn is crucial for myogenic gene regulation and early muscle development. Histone deacetylase inhibitor trichostatin A treatment of SMA model mice increased myofiber size, myofiber maturity and attenuated the disruption of the myogenic program in these mice. Taken together, our work highlights the important contribution of myogenic program dysregulation to the muscle weakness observed in SMA.
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Affiliation(s)
- Justin G Boyer
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada K1H 8L6 Department of Cellular and Molecular Medicine
| | - Marc-Olivier Deguise
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada K1H 8L6 Department of Cellular and Molecular Medicine
| | - Lyndsay M Murray
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada K1H 8L6
| | - Armin Yazdani
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada K1H 8L6 Department of Cellular and Molecular Medicine
| | - Yves De Repentigny
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada K1H 8L6
| | | | - Rashmi Kothary
- Ottawa Hospital Research Institute, Regenerative Medicine Program, Ottawa, ON, Canada K1H 8L6 Department of Cellular and Molecular Medicine Department of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5
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Bowerman M, Michalski JP, Beauvais A, Murray LM, DeRepentigny Y, Kothary R. Defects in pancreatic development and glucose metabolism in SMN-depleted mice independent of canonical spinal muscular atrophy neuromuscular pathology. Hum Mol Genet 2014; 23:3432-44. [PMID: 24497575 PMCID: PMC4049303 DOI: 10.1093/hmg/ddu052] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Spinal muscular atrophy (SMA) is characterized by motor neuron loss, caused by mutations or deletions in the ubiquitously expressed survival motor neuron 1 (SMN1) gene. We recently identified a novel role for Smn protein in glucose metabolism and pancreatic development in both an intermediate SMA mouse model (Smn(2B/-)) and type I SMA patients. In the present study, we sought to determine if the observed metabolic and pancreatic defects are SMA-dependent. We employed a line of heterozygous Smn-depleted mice (Smn(+/-)) that lack the hallmark SMA neuromuscular pathology and overt phenotype. At 1 month of age, pancreatic/metabolic function of Smn(+/-)mice is indistinguishable from wild type. However, when metabolically challenged with a high-fat diet, Smn(+/-)mice display abnormal localization of glucagon-producing α-cells within the pancreatic islets and increased hepatic insulin and glucagon sensitivity, through increased p-AKT and p-CREB, respectively. Further, aging results in weight gain, an increased number of insulin-producing β cells, hyperinsulinemia and increased hepatic glucagon sensitivity in Smn(+/-)mice. Our study uncovers and highlights an important function of Smn protein in pancreatic islet development and glucose metabolism, independent of canonical SMA pathology. These findings suggest that carriers of SMN1 mutations and/or deletions may be at an increased risk of developing pancreatic and glucose metabolism defects, as even small depletions in Smn protein may be a risk factor for diet- and age-dependent development of metabolic disorders.
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Affiliation(s)
- Melissa Bowerman
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada The Neuroscience Institute of Montpellier (INM), Inserm UMR1051, Saint Eloi Hospital, Montpellier, France
| | - John-Paul Michalski
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada Department of Cellular and Molecular Medicine and
| | | | | | | | - Rashmi Kothary
- Ottawa Hospital Research Institute, Ottawa, Ontario, Canada Department of Cellular and Molecular Medicine and Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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20
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Boyer JG, Murray LM, Scott K, De Repentigny Y, Renaud JM, Kothary R. Early onset muscle weakness and disruption of muscle proteins in mouse models of spinal muscular atrophy. Skelet Muscle 2013; 3:24. [PMID: 24119341 PMCID: PMC3852932 DOI: 10.1186/2044-5040-3-24] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/26/2013] [Indexed: 11/12/2022] Open
Abstract
Background The childhood neuromuscular disease spinal muscular atrophy (SMA) is caused by mutations or deletions of the survival motor neuron (SMN1) gene. Although SMA has traditionally been considered a motor neuron disease, the muscle-specific requirement for SMN has never been fully defined. Therefore, the purpose of this study was to investigate muscle defects in mouse models of SMA. Methods We have taken advantage of two different mouse models of SMA, the severe Smn-/-;SMN2 mice and the less severe Smn2B/- mice. We have measured the maximal force produced from control muscles and those of SMA model mice by direct stimulation using an ex vivo apparatus. Immunofluorescence and immunoblot experiments were performed to uncover muscle defects in mouse models of SMA. Means from control and SMA model mice samples were compared using an analysis of variance test and Student’s t tests. Results We report that tibialis anterior (TA) muscles of phenotype stage Smn-/-;SMN2 mice generate 39% less maximal force than muscles from control mice, independently of aberrant motor neuron signal transmission. In addition, during muscle fatigue, the Smn-/-;SMN2 muscle shows early onset and increased unstimulated force compared with controls. Moreover, we demonstrate a significant decrease in force production in muscles from pre-symptomatic Smn-/-;SMN2 and Smn2B/- mice, indicating that muscle weakness is an early event occurring prior to any overt motor neuron loss and muscle denervation. Muscle weakness in mouse models of SMA was associated with a delay in the transition from neonatal to adult isoforms of proteins important for proper muscle contractions, such as ryanodine receptors and sodium channels. Immunoblot analyses of extracts from hindlimb skeletal muscle revealed aberrant levels of the sarcoplasmic reticulum Ca2+ ATPase. Conclusions The findings from this study reveal a delay in the appearance of mature isoforms of proteins important for muscle contractions, as well as muscle weakness early in the disease etiology, thus highlighting the contributions of skeletal muscle defects to the SMA phenotype.
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Affiliation(s)
- Justin G Boyer
- Ottawa Hospital Research Institute, Regenerative Medicine Program, 501 Smyth Road, Ottawa, ON K1H 8L6, Canada.
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Murray LM, Beauvais A, Bhanot K, Kothary R. Defects in neuromuscular junction remodelling in the Smn2B/− mouse model of spinal muscular atrophy. Neurobiol Dis 2013; 49:57-67. [DOI: 10.1016/j.nbd.2012.08.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 08/17/2012] [Accepted: 08/22/2012] [Indexed: 10/28/2022] Open
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Sanchez G, Dury AY, Murray LM, Biondi O, Tadesse H, El Fatimy R, Kothary R, Charbonnier F, Khandjian EW, Côté J. A novel function for the survival motoneuron protein as a translational regulator. Hum Mol Genet 2012; 22:668-84. [PMID: 23136128 DOI: 10.1093/hmg/dds474] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
SMN1, the causative gene for spinal muscular atrophy (SMA), plays a housekeeping role in the biogenesis of small nuclear RNA ribonucleoproteins. SMN is also present in granular foci along axonal projections of motoneurons, which are the predominant cell type affected in the pathology. These so-called RNA granules mediate the transport of specific mRNAs along neurites and regulate mRNA localization, stability, as well as local translation. Recent work has provided evidence suggesting that SMN may participate in the assembly of RNA granules, but beyond that, the precise nature of its role within these structures remains unclear. Here, we demonstrate that SMN associates with polyribosomes and can repress translation in an in vitro translation system. We further identify the arginine methyltransferase CARM1 as an mRNA that is regulated at the translational level by SMN and find that CARM1 is abnormally up-regulated in spinal cord tissue from SMA mice and in severe type I SMA patient cells. We have previously characterized a novel regulatory pathway in motoneurons involving the SMN-interacting RNA-binding protein HuD and CARM1. Thus, our results suggest the existence of a potential negative feedback loop in this pathway. Importantly, an SMA-causing mutation in the Tudor domain of SMN completely abolished translational repression, a strong indication for the functional significance of this novel SMN activity in the pathology.
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Affiliation(s)
- Gabriel Sanchez
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5
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Bowerman M, Murray LM, Boyer JG, Anderson CL, Kothary R. Fasudil improves survival and promotes skeletal muscle development in a mouse model of spinal muscular atrophy. BMC Med 2012; 10:24. [PMID: 22397316 PMCID: PMC3310724 DOI: 10.1186/1741-7015-10-24] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 03/07/2012] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is the leading genetic cause of infant death. It is caused by mutations/deletions of the survival motor neuron 1 (SMN1) gene and is typified by the loss of spinal cord motor neurons, muscular atrophy, and in severe cases, death. The SMN protein is ubiquitously expressed and various cellular- and tissue-specific functions have been investigated to explain the specific motor neuron loss in SMA. We have previously shown that the RhoA/Rho kinase (ROCK) pathway is misregulated in cellular and animal SMA models, and that inhibition of ROCK with the chemical Y-27632 significantly increased the lifespan of a mouse model of SMA. In the present study, we evaluated the therapeutic potential of the clinically approved ROCK inhibitor fasudil. METHODS Fasudil was administered by oral gavage from post-natal day 3 to 21 at a concentration of 30 mg/kg twice daily. The effects of fasudil on lifespan and SMA pathological hallmarks of the SMA mice were assessed and compared to vehicle-treated mice. For the Kaplan-Meier survival analysis, the log-rank test was used and survival curves were considered significantly different at P < 0.05. For the remaining analyses, the Student's two-tail t test for paired variables and one-way analysis of variance (ANOVA) were used to test for differences between samples and data were considered significantly different at P < 0.05. RESULTS Fasudil significantly improves survival of SMA mice. This dramatic phenotypic improvement is not mediated by an up-regulation of Smn protein or via preservation of motor neurons. However, fasudil administration results in a significant increase in muscle fiber and postsynaptic endplate size, and restores normal expression of markers of skeletal muscle development, suggesting that the beneficial effects of fasudil could be muscle-specific. CONCLUSIONS Our work underscores the importance of muscle as a therapeutic target in SMA and highlights the beneficial potential of ROCK inhibitors as a therapeutic strategy for SMA and for other degenerative diseases characterized by muscular atrophy and postsynaptic immaturity.
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Affiliation(s)
- Melissa Bowerman
- Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, ON, Canada K1H 8L6
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Bowerman M, Murray LM, Beauvais A, Pinheiro B, Kothary R. A critical smn threshold in mice dictates onset of an intermediate spinal muscular atrophy phenotype associated with a distinct neuromuscular junction pathology. Neuromuscul Disord 2012; 22:263-76. [DOI: 10.1016/j.nmd.2011.09.007] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 09/07/2011] [Accepted: 09/27/2011] [Indexed: 11/24/2022]
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Mutsaers CA, Wishart TM, Lamont DJ, Riessland M, Schreml J, Comley LH, Murray LM, Parson SH, Lochmüller H, Wirth B, Talbot K, Gillingwater TH. Reversible molecular pathology of skeletal muscle in spinal muscular atrophy. Hum Mol Genet 2011; 20:4334-44. [PMID: 21840928 DOI: 10.1093/hmg/ddr360] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Low levels of full-length survival motor neuron (SMN) protein cause the motor neuron disease, spinal muscular atrophy (SMA). Although motor neurons undoubtedly contribute directly to SMA pathogenesis, the role of muscle is less clear. We demonstrate significant disruption to the molecular composition of skeletal muscle in pre-symptomatic severe SMA mice, in the absence of any detectable degenerative changes in lower motor neurons and with a molecular profile distinct from that of denervated muscle. Functional cluster analysis of proteomic data and phospho-histone H2AX labelling of DNA damage revealed increased activity of cell death pathways in SMA muscle. Robust upregulation of voltage-dependent anion-selective channel protein 2 (Vdac2) and downregulation of parvalbumin in severe SMA mice was confirmed in a milder SMA mouse model and in human patient muscle biopsies. Molecular pathology of skeletal muscle was ameliorated in mice treated with the FDA-approved histone deacetylase inhibitor, suberoylanilide hydroxamic acid. We conclude that intrinsic pathology of skeletal muscle is an important and reversible event in SMA and also suggest that muscle proteins have the potential to act as novel biomarkers in SMA.
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Affiliation(s)
- Chantal A Mutsaers
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, UK
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Comley LH, Wishart TM, Baxter B, Murray LM, Nimmo A, Thomson D, Parson SH, Gillingwater TH. Induction of cell stress in neurons from transgenic mice expressing yellow fluorescent protein: implications for neurodegeneration research. PLoS One 2011; 6:e17639. [PMID: 21408118 PMCID: PMC3050905 DOI: 10.1371/journal.pone.0017639] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 02/04/2011] [Indexed: 11/30/2022] Open
Abstract
Background Mice expressing fluorescent proteins in neurons are one of the most powerful tools in modern neuroscience research and are increasingly being used for in vivo studies of neurodegeneration. However, these mice are often used under the assumption that the fluorescent proteins present are biologically inert. Methodology/Principal Findings Here, we show that thy1-driven expression of yellow fluorescent protein (YFP) in neurons triggers multiple cell stress responses at both the mRNA and protein levels in vivo. The presence of YFP in neurons also subtly altered neuronal morphology and modified the time-course of dying-back neurodegeneration in experimental axonopathy, but not in Wallerian degeneration triggered by nerve injury. Conclusions/Significance We conclude that fluorescent protein expressed in thy1-YFP mice is not biologically inert, modifies molecular and cellular characteristics of neurons in vivo, and has diverse and unpredictable effects on neurodegeneration pathways.
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Affiliation(s)
- Laura H. Comley
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Thomas M. Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Becki Baxter
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Lyndsay M. Murray
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Ailish Nimmo
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Derek Thomson
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Simon H. Parson
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, Lothian, United Kingdom
- * E-mail:
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Affiliation(s)
- Lyndsay M. Murray
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh Medical School Edinburgh UK
| | - Laura H. Comley
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh Medical School Edinburgh UK
| | - Thomas H. Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh Medical School Edinburgh UK
| | - Simon H. Parson
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh Medical School Edinburgh UK
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Wishart TM, Huang JPW, Murray LM, Lamont DJ, Mutsaers CA, Ross J, Geldsetzer P, Ansorge O, Talbot K, Parson SH, Gillingwater TH. SMN deficiency disrupts brain development in a mouse model of severe spinal muscular atrophy. Hum Mol Genet 2010; 19:4216-28. [PMID: 20705736 DOI: 10.1093/hmg/ddq340] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Reduced expression of the survival motor neuron (SMN) gene causes the childhood motor neuron disease spinal muscular atrophy (SMA). Low levels of ubiquitously expressed SMN protein result in the degeneration of lower motor neurons, but it remains unclear whether other regions of the nervous system are also affected. Here we show that reduced levels of SMN lead to impaired perinatal brain development in a mouse model of severe SMA. Regionally selective changes in brain morphology were apparent in areas normally associated with higher SMN levels in the healthy postnatal brain, including the hippocampus, and were associated with decreased cell density, reduced cell proliferation and impaired hippocampal neurogenesis. A comparative proteomics analysis of the hippocampus from SMA and wild-type littermate mice revealed widespread modifications in expression levels of proteins regulating cellular proliferation, migration and development when SMN levels were reduced. This study reveals novel roles for SMN protein in brain development and maintenance and provides the first insights into cellular and molecular pathways disrupted in the brain in a severe form of SMA.
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Affiliation(s)
- Thomas M Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh Medical School, Edinburgh, UK
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Bäumer D, Lee S, Nicholson G, Davies JL, Parkinson NJ, Murray LM, Gillingwater TH, Ansorge O, Davies KE, Talbot K. Alternative splicing events are a late feature of pathology in a mouse model of spinal muscular atrophy. PLoS Genet 2009; 5:e1000773. [PMID: 20019802 PMCID: PMC2787017 DOI: 10.1371/journal.pgen.1000773] [Citation(s) in RCA: 195] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Accepted: 11/16/2009] [Indexed: 11/24/2022] Open
Abstract
Spinal muscular atrophy is a severe motor neuron disease caused by inactivating mutations in the SMN1 gene leading to reduced levels of full-length functional SMN protein. SMN is a critical mediator of spliceosomal protein assembly, and complete loss or drastic reduction in protein leads to loss of cell viability. However, the reason for selective motor neuron degeneration when SMN is reduced to levels which are tolerated by all other cell types is not currently understood. Widespread splicing abnormalities have recently been reported at end-stage in a mouse model of SMA, leading to the proposition that disruption of efficient splicing is the primary mechanism of motor neuron death. However, it remains unclear whether splicing abnormalities are present during early stages of the disease, which would be a requirement for a direct role in disease pathogenesis. We performed exon-array analysis of RNA from SMN deficient mouse spinal cord at 3 time points, pre-symptomatic (P1), early symptomatic (P7), and late-symptomatic (P13). Compared to littermate control mice, SMA mice showed a time-dependent increase in the number of exons showing differential expression, with minimal differences between genotypes at P1 and P7, but substantial variation in late-symptomatic (P13) mice. Gene ontology analysis revealed differences in pathways associated with neuronal development as well as cellular injury. Validation of selected targets by RT–PCR confirmed the array findings and was in keeping with a shift between physiologically occurring mRNA isoforms. We conclude that the majority of splicing changes occur late in SMA and may represent a secondary effect of cell injury, though we cannot rule out significant early changes in a small number of transcripts crucial to motor neuron survival. The identification of mutations in the Survival Motor Neuron (SMN) gene as the cause of the severe motor neuron disorder spinal muscular atrophy is one of a number of discoveries implicating selective motor neuron vulnerability to defects in processing of RNA and its associated ribonucleoprotein complexes. An unresolved issue is whether loss of the general cellular function of SMN in spliceosomal assembly, which is predicted to result in widespread defects in mRNA splicing, is directly responsible for motor neuron death. We have used exon-specific microarrays to assess the degree of altered splicing in the spinal cord in a mouse model of SMA. Our finding that the vast majority of splicing changes are a late feature of the disease and may represent a shift to alternative isoform expression, rather than loss of splicing fidelity, provides evidence that widespread splicing disturbance is not a primary feature of the disease pathogenesis but a secondary effect of cell injury in a late phase of the disease. However, our study cannot rule out a role for subtle early changes in one or a few transcripts crucial to motor neuron survival expressed at low levels or in only in a sub-population of spinal cord cells.
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Affiliation(s)
- Dirk Bäumer
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Sheena Lee
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - George Nicholson
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Joanna L. Davies
- Department of Statistics, University of Oxford, Oxford, United Kingdom
| | - Nicholas J. Parkinson
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Lyndsay M. Murray
- Centre for Integrative Physiology and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh Medical School, Edinburgh, United Kingdom
| | - Thomas H. Gillingwater
- Centre for Integrative Physiology and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh Medical School, Edinburgh, United Kingdom
| | - Olaf Ansorge
- Department of Neuropathology, John Radcliffe Hospital, Oxford, United Kingdom
| | - Kay E. Davies
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Kevin Talbot
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
- Department of Clinical Neurology, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
- * E-mail:
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Murray LM, Lee S, Bäumer D, Parson SH, Talbot K, Gillingwater TH. Pre-symptomatic development of lower motor neuron connectivity in a mouse model of severe spinal muscular atrophy. Hum Mol Genet 2009; 19:420-33. [PMID: 19884170 DOI: 10.1093/hmg/ddp506] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The childhood motor neuron disease spinal muscular atrophy (SMA) results from reduced expression of the survival motor neuron (SMN) gene. Previous studies using in vitro model systems and lower organisms have suggested that low levels of Smn protein disrupt prenatal developmental processes in lower motor neurons, influencing neuronal outgrowth, axon branching and neuromuscular connectivity. The extent to which these developmental pathways contribute to selective vulnerability and pathology in the mammalian neuromuscular system in vivo remains unclear. Here, we have investigated the pre-symptomatic development of neuromuscular connectivity in differentially vulnerable motor neuron populations in Smn(-/-);SMN2 mice, a model of severe SMA. We show that reduced Smn levels have no detectable effect on morphological correlates of pre-symptomatic development in either vulnerable or stable motor units, indicating that abnormal pre-symptomatic developmental processes are unlikely to be a prerequisite for subsequent pathological changes to occur in vivo. Microarray analyses of spinal cord from two different severe SMA mouse models demonstrated that only minimal changes in gene expression were present in pre-symptomatic mice. In stark contrast, microarray analysis of late-symptomatic spinal cord revealed widespread changes in gene expression, implicating extracellular matrix integrity, growth factor signalling and myelination pathways in SMA pathogenesis. Taken together, these data suggest that reduced Smn levels induce SMA pathology by instigating rapidly progressive neurodegenerative pathways in lower motor neurons around the time of disease onset rather than by modulating pre-symptomatic neurodevelopmental pathways.
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Affiliation(s)
- Lyndsay M Murray
- Centre for Integrative Physiology and Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh Medical School, Edinburgh, UK
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Murray LM, Thomson D, Conklin A, Wishart TM, Gillingwater TH. Loss of translation elongation factor (eEF1A2) expression in vivo differentiates between Wallerian degeneration and dying-back neuronal pathology. J Anat 2009; 213:633-45. [PMID: 19094180 DOI: 10.1111/j.1469-7580.2008.01007.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Wallerian degeneration and dying-back pathology are two well-known cellular pathways capable of regulating the breakdown and loss of axonal and synaptic compartments of neurons in vivo. However, the underlying mechanisms and molecular triggers of these pathways remain elusive. Here, we show that loss of translation elongation factor eEF1A2 expression in lower motor neurons and skeletal muscle fibres in homozygous Wasted mice triggered a dying-back neuropathy. Synaptic loss at the neuromuscular junction occurred in advance of axonal pathology and by a mechanism morphologically distinct from Wallerian degeneration. Dying-back pathology in Wasted mice was accompanied by reduced expression levels of the zinc finger protein ZPR1, as found in other dying-back neuropathies such as spinal muscular atrophy. Surprisingly, experimental nerve lesion revealed that Wallerian degeneration was significantly delayed in homozygous Wasted mice; morphological assessment revealed that approximately 80% of neuromuscular junctions in deep lumbrical muscles at 24 h and approximately 50% at 48 h had retained motor nerve terminals following tibial nerve lesion. This was in contrast to wild-type and heterozygous Wasted mice where < 5% of neuromuscular junctions had retained motor nerve terminals at 24 h post-lesion. These data show that eEF1A2 expression is required to prevent the initiation of dying-back pathology at the neuromuscular junction in vivo. In contrast, loss of eEF1A2 expression significantly inhibited the initiation and progression of Wallerian degeneration in vivo. We conclude that loss of eEF1A2 expression distinguishes mechanisms underlying dying-back pathology from those responsible for Wallerian degeneration in vivo and suggest that eEF1A2-dependent cascades may provide novel molecular targets to manipulate neurodegenerative pathways in lower motor neurons.
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Affiliation(s)
- Lyndsay M Murray
- Centre for Integrative Physiology, College of Medicine, and Veterinary Medicine, University of Edinburgh, Edinburgh, EH8 9XD, UK
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Soriano FX, Baxter P, Murray LM, Sporn MB, Gillingwater TH, Hardingham GE. Transcriptional regulation of the AP-1 and Nrf2 target gene sulfiredoxin. Mol Cells 2009; 27:279-82. [PMID: 19326073 PMCID: PMC2837916 DOI: 10.1007/s10059-009-0050-y] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Accepted: 02/15/2009] [Indexed: 01/11/2023] Open
Abstract
"Two-cysteine" peroxiredoxins are antioxidant enzymes that exert a cytoprotective effect in many models of oxidative stress. However, under highly oxidizing conditions they can be inactivated through hyperoxidation of their peroxidatic active site cysteine residue. Sulfiredoxin can reverse this hyperoxidation, thus reactivating peroxiredoxins. Here we review recent investigations that have shed further light on sulfiredoxin's role and regulation. Studies have revealed sulfiredoxin to be a dynamically regulated gene whose transcription is induced by a variety of signals and stimuli. Sulfiredoxin expression is regulated by the transcription factor AP-1, which mediates its up-regulation by synaptic activity in neurons, resulting in protection against oxidative stress. Furthermore, sulfiredoxin has been identified as a new member of the family of genes regulated by nuclear factor erythroid 2-related factor (Nrf2) via a conserved Aáë-acting antioxidant response element (ARE). As such, sulfiredoxin is likely to contribute to the net antioxidative effect of small molecule activators of Nrf2. As discussed here, the proximal AP-1 site of the sulfiredoxin promoter is embedded within the ARE, as is common with Nrf2 target genes. Other recent studies have shown that sulfiredoxin induction via Nrf2 may form an important part of the protective response to oxidative stress in the lung, preventing peroxiredoxin hyperoxidation and, in certain cases, subsequent degradation. We illustrate here that sulfiredoxin can be rapidly induced in vivo by administration of CDDO-TFEA, a synthetic triterpenoid inducer of endogenous Nrf2, which may offer a way of reversing peroxiredoxin hyperoxidation in vivo following chronic or acute oxidative stress.
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Affiliation(s)
- Francesc X. Soriano
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Paul Baxter
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Lyndsay M. Murray
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Michael B. Sporn
- Centre for Neuroscience Research, University of Edinburgh, Edinburgh EH8 9XD, UK; Dartmouth Medical School, 524 Remsen, Hanover NH 03755, USA
| | | | - Giles E. Hardingham
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
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Murray LM, Comley LH, Thomson D, Parkinson N, Talbot K, Gillingwater TH. Selective vulnerability of motor neurons and dissociation of pre- and post-synaptic pathology at the neuromuscular junction in mouse models of spinal muscular atrophy. Hum Mol Genet 2007; 17:949-62. [DOI: 10.1093/hmg/ddm367] [Citation(s) in RCA: 299] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
A Spongosorites sp. collected off southern Australia has yielded 1, 9-dimethylhypoxanthine (4). The structure for 4 was solved by spectroscopic analysis.
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Affiliation(s)
- R J Capon
- School of Chemistry, University of Melbourne, Parkville, Victoria, 3052, Australia.
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Capon RJ, Rooney F, Murray LM, Collins E, Sim ATR, Rostas JAP, Butler MS, Carroll AR. Dragmacidins: new protein phosphatase inhibitors from a southern australian deep-water marine sponge, spongosorites sp. J Nat Prod 1998; 61:660-662. [PMID: 9599272 DOI: 10.1021/np970483t] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A Spongosorites sp. collected during trawling operations off the southern coast of Australia returned the new alkaloid dragmacidin E (3), the structure of which was secured by detailed spectroscopic analysis. Dragmacidin E (3), and its co-metabolite dragmacidin D (1) have been identified as potent inhibitors of serine-threonine protein phosphatases.
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Affiliation(s)
- RJ Capon
- Department of Chemistry, University of Melbourne, Parkville, Victoria 3052, Australia, Faculty of Medicine, The University of Newcastle, University Drive, Callaghan, New South Wales 2308, Australia, and Queensland Pharmaceutical Resea
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Quigley JD, Drewry JJ, Murray LM, Ivey SJ. Effects of lasalocid in milk replacer of calf starter on health and performance of calves challenged with Eimeria species. J Dairy Sci 1997; 80:2972-6. [PMID: 9406090 DOI: 10.3168/jds.s0022-0302(97)76263-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Holstein bull calves (n = 48) were purchased from local sale barns at 3 to 7 d of age and were assigned randomly to a 2 x 2 factorial arrangement of lasalocid in milk replacer (0 or 80 mg/kg) and in calf starter (3 or 44 mg/kg of dry matter). On d 10 after arrival, calves were orally dosed with 100,000 Eimeria oocysts. Intakes of calf starter and milk replacer, body weight (BW), BW gain, excretion of fecal oocysts, and fecal scores were determined. Calves fed lasalocid in milk replacer consumed more calf starter, had greater BW gain, shed fewer oocysts in feces, and scoured less frequently and less severely than did calves fed no lasalocid or those fed lasalocid in calf starter alone. The combination of lasalocid in milk replacer and in calf starter did not improve performance above that of calves fed lasalocid in milk replacer alone. Low intake of calf starter prior to weaning may provide an insufficient amount of lasalocid to control effectively the effects of coccidiosis when calves are infected with Eimeria at an early age. Use of coccidiostats in milk replacers may reduce the effects of coccidiosis in young calves that are infected with Eimeria at an early age.
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Affiliation(s)
- J D Quigley
- Department of Animal Science, University of Tennessee, Knoxville 37901-1071, USA
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Quigley JD, Drewry JJ, Murray LM, Ivey SJ. Body weight gain, feed efficiency, and fecal scores of dairy calves in response to galactosyl-lactose or antibiotics in milk replacers. J Dairy Sci 1997; 80:1751-4. [PMID: 9276816 DOI: 10.3168/jds.s0022-0302(97)76108-3] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Holstein bull calves (n = 96) were purchased at approximately 7 d of age and were assigned to receive 400, 450, 500, and 550 g/d of milk replacer solids during wk 1 to 4, respectively. Treatments were nonmedicated milk replacer plus dried whey, medicated milk replacer (138 mg/kg of oxytetracycline and 276 mg/kg of neomycin) plus dried whey, or nonmedicated milk replacer plus whey processed with beta-galactosidase to contain 15% galactosyl-lactose. Processed whey was added to provide 1% of dry matter as galactosyl-lactose; an equivalent amount of dried whey was added to the other treatments to provide 6.3% of dry matter daily. Intake of milk replacer and fecal scores were measured daily. No calf starter or hay was fed. Body weights were measured weekly from arrival to 26 d. Serum immunoglobulin G, measured 1 d after arrival, averaged 18.3 g/L. Intake of milk replacer plus additive during the 26-d study was 445 g/d and did not vary with treatment. Body weight and body weight gain were increased by 52 and 72 g/d in response to antibiotics and galactosyl-lactose, respectively. Severity of scours and number of days scouring tended to be reduced when calves were fed milk replacer containing galactosyl-lactose or antibiotics.
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Affiliation(s)
- J D Quigley
- Tennessee Agricultural Experiment Station, Department of Animal Science, University of Tennessee, Knoxville 37901-1071, USA
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Sadler WA, Smith MH, Murray LM, Turner JG. A pragmatic approach to estimating total analytical error of immunoassays. Clin Chem 1997; 43:608-14. [PMID: 9105261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Several groups have recently commented on the need for more realistic information on analytical performance of laboratory tests. The term "total analytical error" is sometimes used in this context. However, differing opinions have been expressed on how best to obtain estimates of clinical assay error, as it would be perceived by clinicians. We suggest a pragmatic definition of total analytical error for immunoassays and describe our attempts to estimate it by simple designs in the internal quality-control process. We use results over 29 months from a total serum thyroxine RIA. The most important error sources were those related to calibration materials and operator effects, errors not usually captured by short-term or snapshot experiments.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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Sadler WA, Murray LM, Turner JG. What does "functional sensitivity" mean? Clin Chem 1996; 42:2051-2. [PMID: 8969655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Sadler WA, Murray LM, Turner JG. Influence of specimen carryover on sensitive thyrotropin (TSH) assays: is there a problem? Clin Chem 1996; 42:593-7. [PMID: 8605677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
A relatively slow transition has occurred from so-called 1st-generation thyrotropin (TSH) assays (e.g., RIAs) through 2nd-generation assays (e.g., IRMAs) to 3rd-generation assays (e.g., immunochemiluminometric assays). Analysis of data from a modified internal quality-control design, followed up by a computer simulation, showed that specimen carryover has minimal effect on 2nd-generation TSH assays. However, extension of the simulation to a 3rd-generation assay showed the possibility of substantial effects in the subnormal region. Carryover of 1:1250 (0.08%), for example, may reduce the theoretical 10-fold precision improvement claimed for 3rd-generation assays to nearer fourfold. Simulation results suggest maximum allowable specimen carryover of approximately 1:10,000 (approximately 0.01%) for 3rd-generation TSH assays. We suggest that when automated specimen handling is used in a TSH assay, a well-designed carryover experiment should become a routine part of reports that claim 3rd-generation (or better) performance characteristics.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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Abstract
Abstract
A relatively slow transition has occurred from so-called 1st-generation thyrotropin (TSH) assays (e.g., RIAs) through 2nd-generation assays (e.g., IRMAs) to 3rd-generation assays (e.g., immunochemiluminometric assays). Analysis of data from a modified internal quality-control design, followed up by a computer simulation, showed that specimen carryover has minimal effect on 2nd-generation TSH assays. However, extension of the simulation to a 3rd-generation assay showed the possibility of substantial effects in the subnormal region. Carryover of 1:1250 (0.08%), for example, may reduce the theoretical 10-fold precision improvement claimed for 3rd-generation assays to nearer fourfold. Simulation results suggest maximum allowable specimen carryover of approximately 1:10,000 (approximately 0.01%) for 3rd-generation TSH assays. We suggest that when automated specimen handling is used in a TSH assay, a well-designed carryover experiment should become a routine part of reports that claim 3rd-generation (or better) performance characteristics.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
| | - L M Murray
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
| | - J G Turner
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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Barrow RA, Murray LM, Lim TK, Capon RJ. Mirabilins (A-F): New Alkaloids From a Southern Australian Marine Sponge, Arenochalina mirabilis. Aust J Chem 1996. [DOI: 10.1071/ch9960767] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An Australian marine sponge Arenochalina mirabilis (Lendenfeld 1887) collected from the Great Australian Bight has been found to contain six tricyclic alkaloids, mirabilins A-F (5)-(10), isolated and identified as their N-acetyl derivatives (11)-(16). Structures for the mirabilins were secured by detailed spectroscopic analysis.
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Murray LM, Lim TK, Hooper JNA, Capon RJ. Isobromotopsentin: a New Bis(indole) Alkaloid From a Deep-Water Marine Sponge Spongosorites sp. Aust J Chem 1995. [DOI: 10.1071/ch9952053] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Isobromotopsentin (16) is a new brominated bis(indole) alkaloid isolated from a deep-water marine sponge Spongosorites sp. collected off the southern Australian coast. The structure for (16) was determined by spectroscopic methods.
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Abstract
This case report describes a systemic reaction occurring in a 12-year-old female following presumed envenomation by a brown recluse spider (Loxosceles reclusa). The systemic reaction included self-limited hemolysis necessitating blood transfusion. The clinical course and management are described and compared with those of previously reported cases of systemic loxoscelism.
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Affiliation(s)
- L M Murray
- Department of Emergency Medicine, Vanderbilt University Medical Center, Nashville, TN 37232-4700
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Sadler WA, van der Splinter TM, Murray LM, Turner JG. Calibration of automated thyrotropin assays. Clin Chem 1993; 39:904-5. [PMID: 8485886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Sadler WA, Murray LM, Turner JG. Minimum distinguishable difference in concentration: a clinically oriented translation of assay precision summaries. Clin Chem 1992; 38:1773-8. [PMID: 1526013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A trend to market-driven health care in many parts of the world is focusing increasing attention on getting maximum value from available resources. Laboratories are not exempted. Well-informed clinical input has a potentially valuable role in any laboratory rationalization process. However, a communication difficulty exists in the sense that, although laboratory workers, commercial developers, regulatory bodies, etc., are thoroughly conditioned to using assay coefficient of variation as a general performance measure (for excellent reasons), this is not necessarily the most intuitive or informative scale from a clinician's perspective. Here we use routine clinical data from an immunoradiometric assay of thyrotropin to illustrate, first, a general approach to estimation and prediction of reproducibility, and second, an alternative summary that expresses the discriminatory power of an assay. This latter measure, our experience suggests, is more suited to the way clinicians perceive assays and assay results. The overall aim is improved clinician/laboratory communication.
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Affiliation(s)
- W A Sadler
- Department of Nuclear Medicine, Christchurch Hospital, New Zealand
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Lisker-Melman M, Di Bisceglie AM, Usala SJ, Weintraub B, Murray LM, Hoofnagle JH. Development of thyroid disease during therapy of chronic viral hepatitis with interferon alfa. Gastroenterology 1992; 102:2155-60. [PMID: 1587439 DOI: 10.1016/0016-5085(92)90348-3] [Citation(s) in RCA: 147] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Six of 237 (2.5%) patients with chronic viral hepatitis who were treated with recombinant interferon alfa developed thyroid disease while on treatment. Three patients developed hyperthyroidism, two of whom developed detectable levels of thyroid-stimulating immunoglobulin; three patients developed hypothyroidism in association with high titers of antithyroglobulin and/or antimicrosomal antibodies. The thyroid disease did not remit when interferon therapy was stopped, and all six patients required definitive therapy for the thyroid disease. These findings suggest that a small proportion of patients treated with interferon alfa develop autoimmune reactions and can develop autoimmune thyroid disease.
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Affiliation(s)
- M Lisker-Melman
- Liver Diseases Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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