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Alexandris AS, Koliatsos VE. NAD +, Axonal Maintenance, and Neurological Disease. Antioxid Redox Signal 2023; 39:1167-1184. [PMID: 37503611 PMCID: PMC10715442 DOI: 10.1089/ars.2023.0350] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 05/28/2023] [Indexed: 07/29/2023]
Abstract
Significance: The remarkable geometry of the axon exposes it to unique challenges for survival and maintenance. Axonal degeneration is a feature of peripheral neuropathies, glaucoma, and traumatic brain injury, and an early event in neurodegenerative diseases. Since the discovery of Wallerian degeneration (WD), a molecular program that hijacks nicotinamide adenine dinucleotide (NAD+) metabolism for axonal self-destruction, the complex roles of NAD+ in axonal viability and disease have become research priority. Recent Advances: The discoveries of the protective Wallerian degeneration slow (WldS) and of sterile alpha and TIR motif containing 1 (SARM1) activation as the main instructive signal for WD have shed new light on the regulatory role of NAD+ in axonal degeneration in a growing number of neurological diseases. SARM1 has been characterized as a NAD+ hydrolase and sensor of NAD+ metabolism. The discovery of regulators of nicotinamide mononucleotide adenylyltransferase 2 (NMNAT2) proteostasis in axons, the allosteric regulation of SARM1 by NAD+ and NMN, and the existence of clinically relevant windows of action of these signals has opened new opportunities for therapeutic interventions, including SARM1 inhibitors and modulators of NAD+ metabolism. Critical Issues: Events upstream and downstream of SARM1 remain unclear. Furthermore, manipulating NAD+ metabolism, an overdetermined process crucial in cell survival, for preventing the degeneration of the injured axon may be difficult and potentially toxic. Future Directions: There is a need for clarification of the distinct roles of NAD+ metabolism in axonal maintenance as contrasted to WD. There is also a need to better understand the role of NAD+ metabolism in axonal endangerment in neuropathies, diseases of the white matter, and the early stages of neurodegenerative diseases of the central nervous system. Antioxid. Redox Signal. 39, 1167-1184.
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Affiliation(s)
| | - Vassilis E. Koliatsos
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Neurology, and Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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2
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Jamjoom AAB, Rhodes J, Andrews PJD, Grant SGN. The synapse in traumatic brain injury. Brain 2021; 144:18-31. [PMID: 33186462 PMCID: PMC7880663 DOI: 10.1093/brain/awaa321] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/13/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability worldwide and is a risk factor for dementia later in life. Research into the pathophysiology of TBI has focused on the impact of injury on the neuron. However, recent advances have shown that TBI has a major impact on synapse structure and function through a combination of the immediate mechanical insult and the ensuing secondary injury processes, leading to synapse loss. In this review, we highlight the role of the synapse in TBI pathophysiology with a focus on the confluence of multiple secondary injury processes including excitotoxicity, inflammation and oxidative stress. The primary insult triggers a cascade of events in each of these secondary processes and we discuss the complex interplay that occurs at the synapse. We also examine how the synapse is impacted by traumatic axonal injury and the role it may play in the spread of tau after TBI. We propose that astrocytes play a crucial role by mediating both synapse loss and recovery. Finally, we highlight recent developments in the field including synapse molecular imaging, fluid biomarkers and therapeutics. In particular, we discuss advances in our understanding of synapse diversity and suggest that the new technology of synaptome mapping may prove useful in identifying synapses that are vulnerable or resistant to TBI.
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Affiliation(s)
- Aimun A B Jamjoom
- Centre for Clinical Brain Sciences, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh EH16 4SB, UK
| | - Jonathan Rhodes
- Anaesthesia, Critical Care and Pain Medicine, University of Edinburgh, Edinburgh EH16 4SA, UK
| | - Peter J D Andrews
- Anaesthesia, Critical Care and Pain Medicine, University of Edinburgh, Edinburgh EH16 4SA, UK
| | - Seth G N Grant
- Centre for Clinical Brain Sciences, Chancellor's Building, Edinburgh BioQuarter, University of Edinburgh, Edinburgh EH16 4SB, UK
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
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3
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Phthalide derivative CD21 ameliorates ischemic brain injury in a mouse model of global cerebral ischemia: involvement of inhibition of NLRP3. Int Immunopharmacol 2020; 86:106714. [PMID: 32593156 DOI: 10.1016/j.intimp.2020.106714] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 12/28/2022]
Abstract
The activation of NLRP3 inflammasome is closely related to ischemic brain injury and inhibition of NLRP3 inflammasome activation may be a new therapeutic strategy for ischemic stroke. Our previous studies showed that ligustilide (LIG) had a dose-dependent neuroprotective effect on various models of cerebral ischemia and dementia in vivo and in vitro. CD21, a kind of phthalide derivative, was modified from LIG. In this study, we established a global cerebral ischemia-reperfusion model in mice by bilateral common carotid artery ligation (2VO), and explored the neuroprotective effect of CD21 and its anti-inflammatory mechanism on cerebral ischemia mice. CD21 significantly improved weight loss, neurobehavioral deficits and neurons loss in hippocampal CA1 and caudate putamen (CPu) subregions, which were induced by 2VO in mice. CD21 significantly inhibited the overactivation of astrocyte and microglia, and decreased the mRNA level of IL-6, TNF-α and IL-1β. Moreover, CD21 significantly inhibited the activation of TLR4/NF-κB signaling pathway mediated by HMGB1 and NLRP3/ASC/Caspase-1 signaling pathway mediated by Cathepsin B, thus inhibiting the activation of NLRP3 inflammasome. Our results demonstrated that CD21 may exert a neuroprotection by inhibiting NLRP3 inflammasome activation after cerebral ischemia. These findings provide a new strategy for the treatment of ischemic stroke.
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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] [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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Krauss R, Bosanac T, Devraj R, Engber T, Hughes RO. Axons Matter: The Promise of Treating Neurodegenerative Disorders by Targeting SARM1-Mediated Axonal Degeneration. Trends Pharmacol Sci 2020; 41:281-293. [DOI: 10.1016/j.tips.2020.01.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2019] [Revised: 01/09/2020] [Accepted: 01/13/2020] [Indexed: 02/06/2023]
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Altered mitochondrial bioenergetics are responsible for the delay in Wallerian degeneration observed in neonatal mice. Neurobiol Dis 2019; 130:104496. [PMID: 31176719 PMCID: PMC6704473 DOI: 10.1016/j.nbd.2019.104496] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 04/26/2019] [Accepted: 06/05/2019] [Indexed: 01/10/2023] Open
Abstract
Neurodegenerative and neuromuscular disorders can manifest throughout the lifespan of an individual, from infant to elderly individuals. Axonal and synaptic degeneration are early and critical elements of nearly all human neurodegenerative diseases and neural injury, however the molecular mechanisms which regulate this process are yet to be fully elucidated. Furthermore, how the molecular mechanisms governing degeneration are impacted by the age of the individual is poorly understood. Interestingly, in mice which are under 3 weeks of age, the degeneration of axons and synapses following hypoxic or traumatic injury is significantly slower. This process, known as Wallerian degeneration (WD), is a molecularly and morphologically distinct subtype of neurodegeneration by which axons and synapses undergo distinct fragmentation and death following a range of stimuli. In this study, we first use an ex-vivo model of axon injury to confirm the significant delay in WD in neonatal mice. We apply tandem mass-tagging quantitative proteomics to profile both nerve and muscle between P12 and P24 inclusive. Application of unbiased in silico workflows to relevant protein identifications highlights a steady elevation in oxidative phosphorylation cascades corresponding to the accelerated degeneration rate. We demonstrate that inhibition of Complex I prevents the axotomy-induced rise in reactive oxygen species and protects axons following injury. Furthermore, we reveal that pharmacological activation of oxidative phosphorylation significantly accelerates degeneration at the neuromuscular junction in neonatal mice. In summary, we reveal dramatic changes in the neuromuscular proteome during post-natal maturation of the neuromuscular system, and demonstrate that endogenous dynamics in mitochondrial bioenergetics during this time window have a functional impact upon regulating the stability of the neuromuscular system.
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Syc-Mazurek SB, Libby RT. Axon injury signaling and compartmentalized injury response in glaucoma. Prog Retin Eye Res 2019; 73:100769. [PMID: 31301400 DOI: 10.1016/j.preteyeres.2019.07.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 07/05/2019] [Accepted: 07/09/2019] [Indexed: 12/19/2022]
Abstract
Axonal degeneration is an active, highly controlled process that contributes to beneficial processes, such as developmental pruning, but also to neurodegeneration. In glaucoma, ocular hypertension leads to vision loss by killing the output neurons of the retina, the retinal ganglion cells (RGCs). Multiple processes have been proposed to contribute to and/or mediate axonal injury in glaucoma, including: neuroinflammation, loss of neurotrophic factors, dysregulation of the neurovascular unit, and disruption of the axonal cytoskeleton. While the inciting injury to RGCs in glaucoma is complex and potentially heterogeneous, axonal injury is ultimately thought to be the key insult that drives glaucomatous neurodegeneration. Glaucomatous neurodegeneration is a complex process, with multiple molecular signals contributing to RGC somal loss and axonal degeneration. Furthermore, the propagation of the axonal injury signal is complex, with injury triggering programs of degeneration in both the somal and axonal compartment. Further complicating this process is the involvement of multiple cell types that are known to participate in the process of axonal and neuronal degeneration after glaucomatous injury. Here, we review the axonal signaling that occurs after injury and the molecular signaling programs currently known to be important for somal and axonal degeneration after glaucoma-relevant axonal injuries.
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Affiliation(s)
- Stephanie B Syc-Mazurek
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY, USA; Neuroscience Graduate Program, University of Rochester Medical Center, Rochester, NY, USA
| | - Richard T Libby
- Department of Ophthalmology, University of Rochester Medical Center, Rochester, NY, USA; Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY, USA; The Center for Visual Sciences, University of Rochester, Rochester, NY, USA.
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8
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Sun J, Wang F, Ling Z, Yu X, Chen W, Li H, Jin J, Pang M, Zhang H, Yu J, Liu J. Clostridium butyricum attenuates cerebral ischemia/reperfusion injury in diabetic mice via modulation of gut microbiota. Brain Res 2016; 1642:180-188. [PMID: 27037183 DOI: 10.1016/j.brainres.2016.03.042] [Citation(s) in RCA: 91] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 02/29/2016] [Accepted: 03/28/2016] [Indexed: 12/26/2022]
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Amorim IS, Mitchell NL, Palmer DN, Sawiak SJ, Mason R, Wishart TM, Gillingwater TH. Molecular neuropathology of the synapse in sheep with CLN5 Batten disease. Brain Behav 2015; 5:e00401. [PMID: 26664787 PMCID: PMC4667763 DOI: 10.1002/brb3.401] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 08/25/2015] [Accepted: 09/02/2015] [Indexed: 12/26/2022] Open
Abstract
AIMS Synapses represent a major pathological target across a broad range of neurodegenerative conditions. Recent studies addressing molecular mechanisms regulating synaptic vulnerability and degeneration have relied heavily on invertebrate and mouse models. Whether similar molecular neuropathological changes underpin synaptic breakdown in large animal models and in human patients with neurodegenerative disease remains unclear. We therefore investigated whether molecular regulators of synaptic pathophysiology, previously identified in Drosophila and mouse models, are similarly present and modified in the brain of sheep with CLN5 Batten disease. METHODS Gross neuropathological analysis of CLN5 Batten disease sheep and controls was used alongside postmortem MRI imaging to identify affected brain regions. Synaptosome preparations were then generated and quantitative fluorescent Western blotting used to determine and compare levels of synaptic proteins. RESULTS The cortex was particularly affected by regional neurodegeneration and synaptic loss in CLN5 sheep, whilst the cerebellum was relatively spared. Quantitative assessment of the protein content of synaptosome preparations revealed significant changes in levels of seven out of eight synaptic neurodegeneration proteins investigated in the motor cortex, but not cerebellum, of CLN5 sheep (α-synuclein, CSP-α, neurofascin, ROCK2, calretinin, SIRT2, and UBR4). CONCLUSIONS Synaptic pathology is a robust correlate of region-specific neurodegeneration in the brain of CLN5 sheep, driven by molecular pathways similar to those reported in Drosophila and rodent models. Thus, large animal models, such as sheep, represent ideal translational systems to develop and test therapeutics aimed at delaying or halting synaptic pathology for a range of human neurodegenerative conditions.
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Affiliation(s)
- Inês S Amorim
- Centre for Integrative Physiology University of Edinburgh Hugh Robson Building Edinburgh UK ; Euan MacDonald Centre for Motor Neurone Disease Research University of Edinburgh Hugh Robson Building Edinburgh UK
| | - Nadia L Mitchell
- Department of Molecular Biosciences Faculty of Agricultural and Life Sciences and Batten Animal Research Network Lincoln University Christchurch New Zealand
| | - David N Palmer
- Department of Molecular Biosciences Faculty of Agricultural and Life Sciences and Batten Animal Research Network Lincoln University Christchurch New Zealand
| | - Stephen J Sawiak
- Department of Physiology, Development and Neuroscience University of Cambridge Downing Street Cambridge UK ; Wolfson Brain Imaging Centre University of Cambridge Box 65 Addenbrooke's Hospital Hills Road Cambridge UK
| | - Roger Mason
- Department of Physiology, Development and Neuroscience University of Cambridge Downing Street Cambridge UK
| | - Thomas M Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research University of Edinburgh Hugh Robson Building Edinburgh UK ; Division of Neurobiology The Roslin Institute and Royal (Dick) School of Veterinary Studies University of Edinburgh Edinburgh UK
| | - Thomas H Gillingwater
- Centre for Integrative Physiology University of Edinburgh Hugh Robson Building Edinburgh UK ; Euan MacDonald Centre for Motor Neurone Disease Research University of Edinburgh Hugh Robson Building Edinburgh UK
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Mundinger TO, Cooper E, Coleman MP, Taborsky GJ. Short-term diabetic hyperglycemia suppresses celiac ganglia neurotransmission, thereby impairing sympathetically mediated glucagon responses. Am J Physiol Endocrinol Metab 2015; 309:E246-55. [PMID: 26037249 PMCID: PMC4525110 DOI: 10.1152/ajpendo.00140.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/25/2015] [Indexed: 01/09/2023]
Abstract
Short-term hyperglycemia suppresses superior cervical ganglia neurotransmission. If this ganglionic dysfunction also occurs in the islet sympathetic pathway, sympathetically mediated glucagon responses could be impaired. Our objectives were 1) to test for a suppressive effect of 7 days of streptozotocin (STZ) diabetes on celiac ganglia (CG) activation and on neurotransmitter and glucagon responses to preganglionic nerve stimulation, 2) to isolate the defect in the islet sympathetic pathway to the CG itself, and 3) to test for a protective effect of the WLD(S) mutation. We injected saline or nicotine in nondiabetic and STZ-diabetic rats and measured fos mRNA levels in whole CG. We electrically stimulated the preganglionic or postganglionic nerve trunk of the CG in nondiabetic and STZ-diabetic rats and measured portal venous norepinephrine and glucagon responses. We repeated the nicotine and preganglionic nerve stimulation studies in nondiabetic and STZ-diabetic WLD(S) rats. In STZ-diabetic rats, the CG fos response to nicotine was suppressed, and the norepinephrine and glucagon responses to preganglionic nerve stimulation were impaired. In contrast, the norepinephrine and glucagon responses to postganglionic nerve stimulation were normal. The CG fos response to nicotine, and the norepinephrine and glucagon responses to preganglionic nerve stimulation, were normal in STZ-diabetic WLD(S) rats. In conclusion, short-term hyperglycemia's suppressive effect on nicotinic acetylcholine receptors of the CG impairs sympathetically mediated glucagon responses. WLD(S) rats are protected from this dysfunction. The implication is that this CG dysfunction may contribute to the impaired glucagon response to insulin-induced hypoglycemia seen early in type 1 diabetes.
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MESH Headings
- Animals
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/physiopathology
- Down-Regulation/drug effects
- Electric Stimulation
- Ganglia, Sympathetic/drug effects
- Ganglia, Sympathetic/metabolism
- Ganglia, Sympathetic/physiopathology
- Ganglionic Stimulants/pharmacology
- Glucagon/blood
- Glucagon/metabolism
- Hyperglycemia/etiology
- Islets of Langerhans/drug effects
- Islets of Langerhans/innervation
- Islets of Langerhans/metabolism
- Male
- Mutant Proteins/metabolism
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Nicotinic Agonists/pharmacology
- Norepinephrine/blood
- Norepinephrine/metabolism
- Proto-Oncogene Proteins c-fos/genetics
- Proto-Oncogene Proteins c-fos/metabolism
- Rats, Sprague-Dawley
- Rats, Transgenic
- Rats, Wistar
- Receptors, Nicotinic/chemistry
- Receptors, Nicotinic/metabolism
- Synaptic Transmission/drug effects
- Wallerian Degeneration/complications
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Affiliation(s)
| | - Ellis Cooper
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Michael P Coleman
- The Babraham Institute, Babraham Research Campus, Babraham, Cambridge, United Kingdom; and
| | - Gerald J Taborsky
- Department of Medicine, University of Washington, Seattle, Washington; Veterans Affairs Puget Sound Health Care System, Seattle, Washington
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Brown R, Hynes-Allen A, Swan AJ, Dissanayake KN, Gillingwater TH, Ribchester RR. Activity-dependent degeneration of axotomized neuromuscular synapses in Wld S mice. Neuroscience 2015; 290:300-20. [PMID: 25617654 PMCID: PMC4362769 DOI: 10.1016/j.neuroscience.2015.01.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 01/10/2015] [Accepted: 01/12/2015] [Indexed: 12/12/2022]
Abstract
Use and disuse may influence synaptic maintenance but so far evidence for this has been indirect. We tested whether stimulation or disuse of neuromuscular junctions in adult WldS mice altered vulnerability to axotomy. Moderate activity optimized resistance to axotomy while disuse or stimulation increased the rate of synaptic degeneration.
Activity and disuse of synapses are thought to influence progression of several neurodegenerative diseases in which synaptic degeneration is an early sign. Here we tested whether stimulation or disuse renders neuromuscular synapses more or less vulnerable to degeneration, using axotomy as a robust trigger. We took advantage of the slow synaptic degeneration phenotype of axotomized neuromuscular junctions in flexor digitorum brevis (FDB) and deep lumbrical (DL) muscles of Wallerian degeneration-Slow (WldS) mutant mice. First, we maintained ex vivo FDB and DL nerve-muscle explants at 32 °C for up to 48 h. About 90% of fibers from WldS mice remained innervated, compared with about 36% in wild-type muscles at the 24-h checkpoint. Periodic high-frequency nerve stimulation (100 Hz: 1 s/100 s) reduced synaptic protection in WldS preparations by about 50%. This effect was abolished in reduced Ca2+ solutions. Next, we assayed FDB and DL innervation after 7 days of complete tetrodotoxin (TTX)-block of sciatic nerve conduction in vivo, followed by tibial nerve axotomy. Five days later, only about 9% of motor endplates remained innervated in the paralyzed muscles, compared with about 50% in 5 day-axotomized muscles from saline-control-treated WldS mice with no conditioning nerve block. Finally, we gave mice access to running wheels for up to 4 weeks prior to axotomy. Surprisingly, exercising WldS mice ad libitum for 4 weeks increased about twofold the amount of subsequent axotomy-induced synaptic degeneration. Together, the data suggest that vulnerability of mature neuromuscular synapses to axotomy, a potent neurodegenerative trigger, may be enhanced bimodally, either by disuse or by hyperactivity.
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Affiliation(s)
- R Brown
- Euan MacDonald Centre for Motor Neurone Disease Research, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - A Hynes-Allen
- Euan MacDonald Centre for Motor Neurone Disease Research, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - A J Swan
- Euan MacDonald Centre for Motor Neurone Disease Research, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - K N Dissanayake
- Euan MacDonald Centre for Motor Neurone Disease Research, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - T H Gillingwater
- Euan MacDonald Centre for Motor Neurone Disease Research, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK
| | - R R Ribchester
- Euan MacDonald Centre for Motor Neurone Disease Research, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh EH8 9XD, UK.
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12
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Wallerian degeneration: an emerging axon death pathway linking injury and disease. Nat Rev Neurosci 2014; 15:394-409. [DOI: 10.1038/nrn3680] [Citation(s) in RCA: 387] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Zhu S, Yang Y, Hu J, Qian L, Jiang Y, Li X, Yang Q, Bai H, Chen Q. Wld(S) ameliorates renal injury in a type 1 diabetic mouse model. Am J Physiol Renal Physiol 2014; 306:F1348-56. [PMID: 24598800 DOI: 10.1152/ajprenal.00418.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease worldwide. The purpose of this study is to investigate whether the Wld(S) (slow Wallerian degeneration; also known as Wld) gene plays a renoprotective role during the progression of DN. Diabetes was induced in 8-wk-old male wild-type (WT) and C57BL/Wld(S) mice by streptozotocin (STZ) injection. Blood and urinary variables including blood glucose, glycated hemoglobin (GHb), insulin, urea nitrogen, and albumin/creatinine ratio were assessed 4, 7, and 14 wk after STZ injection. Periodic acid-Schiff staining, Masson staining, and silver staining were performed for renal pathological analyses. In addition, the renal ultrastructure was observed by electron microscope. The activities of p38 and ERK signaling in renal cortical tissues were evaluated by Western blotting. NAD(+)/NADH ratio and NADPH oxidase activity were also measured. Moreover, the expressions of TNF-α, IL-1, and IL-6 were examined. We provide experimental evidence demonstrating that the Wld(S) gene is expressed in kidney cells and protects against the early stage of diabetes-induced renal dysfunction and extracellular matrix accumulation through delaying the reduction of the NAD(+)/NADH ratio, inhibiting the activation of p38 and ERK signaling, and suppressing oxidative stress as evidenced by the decreased NADPH oxidase activity and lower expression of TNF-α, IL-1, and IL-6.
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Affiliation(s)
- Shuaishuai Zhu
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Yelin Yang
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Jin Hu
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Lingling Qian
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Yuchen Jiang
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Xiaoyu Li
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qing Yang
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Hui Bai
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qi Chen
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
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14
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Sodium and potassium currents influence Wallerian degeneration of injured Drosophila axons. J Neurosci 2014; 33:18728-39. [PMID: 24285879 DOI: 10.1523/jneurosci.1007-13.2013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Axons degenerate after injury and in neuropathies and disease via a self-destruction program whose mechanism is poorly understood. Axons that have lost connection to their cell bodies have altered electrical and synaptic activities, but whether such changes play a role in the axonal degeneration process is not clear. We have used a Drosophila model to study the Wallerian degeneration of motoneuron axons and their neuromuscular junction synapses. We found that degeneration of the distal nerve stump after a nerve crush is greatly delayed when there is increased potassium channel activity (by overexpression of two different potassium channels, Kir2.1 and dORKΔ-C) or decreased voltage-gated sodium channel activity (using mutations in the para sodium channel). Conversely, degeneration is accelerated when potassium channel activity is decreased (by expressing a dominant-negative mutation of Shaker). Despite the effect of altering voltage-gated sodium and potassium channel activity, recordings made after nerve crush demonstrated that the distal stump does not fire action potentials. Rather, a variety of lines of evidence suggest that the sodium and potassium channels manifest their effects upon degeneration through changes in the resting membrane potential, which in turn regulates the level of intracellular free calcium within the isolated distal axon.
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Beirowski B. Concepts for regulation of axon integrity by enwrapping glia. Front Cell Neurosci 2013; 7:256. [PMID: 24391540 PMCID: PMC3867696 DOI: 10.3389/fncel.2013.00256] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 11/25/2013] [Indexed: 12/16/2022] Open
Abstract
Long axons and their enwrapping glia (EG; Schwann cells (SCs) and oligodendrocytes (OLGs)) form a unique compound structure that serves as conduit for transport of electric and chemical information in the nervous system. The peculiar cytoarchitecture over an enormous length as well as its substantial energetic requirements make this conduit particularly susceptible to detrimental alterations. Degeneration of long axons independent of neuronal cell bodies is observed comparatively early in a range of neurodegenerative conditions as a consequence of abnormalities in SCs and OLGs . This leads to the most relevant disease symptoms and highlights the critical role that these glia have for axon integrity, but the underlying mechanisms remain elusive. The quest to understand why and how axons degenerate is now a crucial frontier in disease-oriented research. This challenge is most likely to lead to significant progress if the inextricable link between axons and their flanking glia in pathological situations is recognized. In this review I compile recent advances in our understanding of the molecular programs governing axon degeneration, and mechanisms of EG’s non-cell autonomous impact on axon-integrity. A particular focus is placed on emerging evidence suggesting that EG nurture long axons by virtue of their intimate association, release of trophic substances, and neurometabolic coupling. The correction of defects in these functions has the potential to stabilize axons in a variety of neuronal diseases in the peripheral nervous system and central nervous system (PNS and CNS).
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Affiliation(s)
- Bogdan Beirowski
- Department of Genetics, Washington University School of Medicine Saint Louis, MO, USA
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Calliari A, Bobba N, Escande C, Chini EN. Resveratrol delays Wallerian degeneration in a NAD(+) and DBC1 dependent manner. Exp Neurol 2013; 251:91-100. [PMID: 24252177 DOI: 10.1016/j.expneurol.2013.11.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 11/06/2013] [Accepted: 11/10/2013] [Indexed: 01/12/2023]
Abstract
Axonal degeneration is a central process in the pathogenesis of several neurodegenerative diseases. Understanding the molecular mechanisms that are involved in axonal degeneration is crucial to developing new therapies against diseases involving neuronal damage. Resveratrol is a putative SIRT1 activator that has been shown to delay neurodegenerative diseases, including Amyotrophic Lateral Sclerosis, Alzheimer, and Huntington's disease. However, the effect of resveratrol on axonal degeneration is still controversial. Using an in vitro model of Wallerian degeneration based on cultures of explants of the dorsal root ganglia (DRG), we showed that resveratrol produces a delay in axonal degeneration. Furthermore, the effect of resveratrol on Wallerian degeneration was lost when SIRT1 was pharmacologically inhibited. Interestingly, we found that knocking out Deleted in Breast Cancer-1 (DBC1), an endogenous SIRT1 inhibitor, restores the neuroprotective effect of resveratrol. However, resveratrol did not have an additive protective effect in DBC1 knockout-derived DRGs, suggesting that resveratrol and DBC1 are working through the same signaling pathway. We found biochemical evidence suggesting that resveratrol protects against Wallerian degeneration by promoting the dissociation of SIRT1 and DBC1 in cultured ganglia. Finally, we demonstrated that resveratrol can delay degeneration of crushed nerves in vivo. We propose that resveratrol protects against Wallerian degeneration by activating SIRT1 through dissociation from its inhibitor DBC1.
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Affiliation(s)
- Aldo Calliari
- Department of Molecular and Cellular Biology, School of Veterinary-UdelaR., Av. A. Lasplaces 1550, CP 11600, Montevideo, Uruguay; Department of Protein and Nucleic Acids, IIBCE-MEC, Av. Italia 3318, CP 11600, Montevideo, Uruguay.
| | - Natalia Bobba
- Department of Protein and Nucleic Acids, IIBCE-MEC, Av. Italia 3318, CP 11600, Montevideo, Uruguay
| | - Carlos Escande
- Laboratory of Signal Transduction, Department of Anesthesiology and Kogod Center on Aging, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
| | - Eduardo N Chini
- Laboratory of Signal Transduction, Department of Anesthesiology and Kogod Center on Aging, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA.
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Maintaining energy homeostasis is an essential component of Wld(S)-mediated axon protection. Neurobiol Dis 2013; 59:69-79. [PMID: 23892229 DOI: 10.1016/j.nbd.2013.07.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 07/02/2013] [Accepted: 07/12/2013] [Indexed: 12/18/2022] Open
Abstract
Wld(S) mutation protects axons from degeneration in diverse experimental models of neurological disorders, suggesting that the mutation might act on a key step shared by different axon degeneration pathways. Here we test the hypothesis that Wld(S) protects axons by preventing energy deficiency commonly encountered in many diseases. We subjected compartmentally cultured, mouse cortical axons to energy deprivation with 6mM azide and zero glucose. In wild-type (WT) culture, the treatment, which reduced axon ATP level ([ATP]axon) by 65%, caused immediate axon depolarization followed by gradual free calcium accumulation and subsequent irreversible axon damage. The calcium accumulation resulted from calcium influx partially via L-type voltage-gated calcium channel (L-VGCC). Blocking L-VGCC with nimodipine reduced calcium accumulation and protected axons. Without altering baseline [ATP]axon, the presence of Wld(S) mutation significantly reduced the axon ATP loss and depolarization, restrained the subsequent calcium accumulation, and protected axons against energy deprivation. Wld(S) neurons possessed higher than normal nicotinamide mononucleotide adenylyltransferase (NMNAT) activity. The intrinsic Wld(S) NMNAT activity was required for the Wld(S)-mediated energy preservation and axon protection during but not prior to energy deprivation. NMNAT catalyzes the reversible reaction that produces nicotinamide adenine dinucleotide (NAD) from nicotinamide mononucleotide (NMN). Interestingly, preventing the production of NAD from NMN with FK866 increased [ATP]axon and protected axons from energy deprivation. These results indicate that the Wld(S) mutation depends on its intrinsic Wld(S) NMNAT activity and the subsequent increase in axon ATP but not NAD to protect axons, implicating a novel role of Wld(S) NMNAT in axon bioenergetics and protection.
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Zhang T, Yan W, Li Q, Fu J, Liu K, Jia W, Sun X, Liu X. 3-n-butylphthalide (NBP) attenuated neuronal autophagy and amyloid-beta expression in diabetic mice subjected to brain ischemia. Neurol Res 2013; 33:396-404. [DOI: 10.1179/1743132810y.0000000006] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Zhu Y, Zhang L, Sasaki Y, Milbrandt J, Gidday JM. Protection of mouse retinal ganglion cell axons and soma from glaucomatous and ischemic injury by cytoplasmic overexpression of Nmnat1. Invest Ophthalmol Vis Sci 2013; 54:25-36. [PMID: 23211826 DOI: 10.1167/iovs.12-10861] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
PURPOSE The Wlds mutation affords protection of retinal ganglion cell (RGC) axons in retinal ischemia and in inducible and hereditary preclinical models of glaucoma. We undertook the present study to determine whether the Nmnat1 portion of the chimeric protein provides axonal and somatic protection of RGCs in models of ischemia and glaucoma, particularly when localized to nonnuclear regions of the cell. METHODS The survival and integrity of RGC axons and soma from transgenic mice with confirmed cytoplasmic overexpression of Nmnat1 in retina and optic nerve (cytNmnat1-Tg mice) were examined in the retina and postlaminar optic nerve 4 days following acute retinal ischemia, and 3 weeks following the chronic elevation of intraocular pressure. RESULTS Ischemia- and glaucoma-induced disruptions of proximal segments of RGC axons that comprise the nerve fiber layer in wild-type mice were both robustly abrogated in cytNmnat1-Tg mice. More distal portions of RGC axons within the optic nerve were also protected from glaucomatous disruption in the transgenic mice. In both disease models, Nmnat1 overexpression in extranuclear locations significantly enhanced the survival of RGC soma. CONCLUSIONS Overexpression of Nmnat1 in the cytoplasm and axons of RGCs robustly protected against both ischemic and glaucomatous loss of RGC axonal integrity, as well as loss of RGC soma. These findings reflect the more pan-cellular protection of CNS neurons that is realized by cytoplasmic Nmnat1 expression, and thus provide a therapeutic strategy for protecting against retinal neurodegeneration, and perhaps other CNS neurodegenerative diseases as well.
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Affiliation(s)
- Yanli Zhu
- Department of Neurosurgery, Washington University School of Medicine, St. Louis, MO 63110, USA
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Li R, Xu X, Chen C, Yu X, Edin ML, Degraff LM, Lee CR, Zeldin DC, Wang DW. Cytochrome P450 2J2 is protective against global cerebral ischemia in transgenic mice. Prostaglandins Other Lipid Mediat 2012; 99:68-78. [PMID: 23041291 DOI: 10.1016/j.prostaglandins.2012.09.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 09/20/2012] [Accepted: 09/24/2012] [Indexed: 12/18/2022]
Abstract
Cytochrome P450 epoxygenase metabolites of arachidonic acid, EETs, have multiple cardiovascular effects, including reduction of blood pressure, protection against myocardial ischemia-reperfusion injury, and attenuation of endothelial apoptosis. This study investigated the hypothesis that transgenic mice with endothelial overexpression of CYP2J2 (Tie2-CYP2J2-Tr) would be protected against global cerebral ischemia induced by bilateral common carotid artery occlusion (BCCAO) and action mechanisms of EETs on cerebral ischemia in cultures of astrocytes exposed to oxygen-glucose deprivation (OGD). Tie2-CYP2J2-Tr mice had significantly increased CYP2J2 expression, increased 14,15-EET production, increases regional cerebral blood flow (rCBF) and microvascular density, decreased ROS production, decreased brain infarct size and apoptosis after ischemia compared to wild type mice, these were associated with increased activation of the PI3K/AKT and apoptosis-related protein in ischemic brain. Addition of exogenous EETs or CYP2J2 transfection attenuated OGD-induced apoptosis in astrocytes via activation of PI3K/AKT and anti-apoptosis pathways. However, these effects were reduced by pretreatments with inhibitor of the PI3K (LY294002) and 14,15-EET (14,15-EEZE), respectively. These results indicate that CYP2J2 overexpression exerts marked neuroprotective effects against ischemic injury by a mechanism linked to increased level of circulating EETs and increases CBF and reduction of apoptosis.
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Affiliation(s)
- Rui Li
- Department of Internal Medicine and Gene Therapy Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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Lorber B, Tassoni A, Bull ND, Moschos MM, Martin KR. Retinal ganglion cell survival and axon regeneration in WldS transgenic rats after optic nerve crush and lens injury. BMC Neurosci 2012; 13:56. [PMID: 22672534 PMCID: PMC3404964 DOI: 10.1186/1471-2202-13-56] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 06/06/2012] [Indexed: 11/22/2022] Open
Abstract
Background We have previously shown that the slow Wallerian degeneration mutation, whilst delaying axonal degeneration after optic nerve crush, does not protect retinal ganglion cell (RGC) bodies in adult rats. To test the effects of a combination approach protecting both axons and cell bodies we performed combined optic nerve crush and lens injury, which results in both enhanced RGC survival as well as axon regeneration past the lesion site in wildtype animals. Results As previously reported we found that the WldS mutation does not protect RGC bodies after optic nerve crush alone. Surprisingly, we found that WldS transgenic rats did not exhibit the enhanced RGC survival response after combined optic nerve crush and lens injury that was observed in wildtype rats. RGC axon regeneration past the optic nerve lesion site was, however, similar in WldS and wildtypes. Furthermore, activation of retinal glia, previously shown to be associated with enhanced RGC survival and axon regeneration after optic nerve crush and lens injury, was unaffected in WldS transgenic rats. Conclusions RGC axon regeneration is similar between WldS transgenic and wildtype rats, but WldS transgenic rats do not exhibit enhanced RGC survival after combined optic nerve crush and lens injury suggesting that the neuroprotective effects of lens injury on RGC survival may be limited by the WldS protein.
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Antenor-Dorsey JAV, O'Malley KL. WldS but not Nmnat1 protects dopaminergic neurites from MPP+ neurotoxicity. Mol Neurodegener 2012; 7:5. [PMID: 22315973 PMCID: PMC3322348 DOI: 10.1186/1750-1326-7-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 02/08/2012] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND The WldS mouse mutant ("Wallerian degeneration-slow") delays axonal degeneration in a variety of disorders including in vivo models of Parkinson's disease. The mechanisms underlying WldS -mediated axonal protection are unclear, although many studies have attributed WldS neuroprotection to the NAD+-synthesizing Nmnat1 portion of the fusion protein. Here, we used dissociated dopaminergic cultures to test the hypothesis that catalytically active Nmnat1 protects dopaminergic neurons from toxin-mediated axonal injury. RESULTS Using mutant mice and lentiviral transduction of dopaminergic neurons, the present findings demonstrate that WldS but not Nmnat1, Nmnat3, or cytoplasmically-targeted Nmnat1 protects dopamine axons from the parkinsonian mimetic N-methyl-4-phenylpyridinium (MPP+). Moreover, NAD+ synthesis is not required since enzymatically-inactive WldS still protects. In addition, NAD+ by itself is axonally protective and together with WldS is additive in the MPP+ model. CONCLUSIONS Our data suggest that NAD+ and WldS act through separate and possibly parallel mechanisms to protect dopamine axons. As MPP+ is thought to impair mitochondrial function, these results suggest that WldS might be involved in preserving mitochondrial health or maintaining cellular metabolism.
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Affiliation(s)
- Jo Ann V Antenor-Dorsey
- Department of Anatomy and Neurobiology, Washington University School of Medicine, Saint Louis, MO 63110, USA
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Tokunaga S, Araki T. Wallerian degeneration slow mouse neurons are protected against cell death caused by mechanisms involving mitochondrial electron transport dysfunction. J Neurosci Res 2011; 90:664-71. [DOI: 10.1002/jnr.22792] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 08/08/2011] [Accepted: 08/22/2011] [Indexed: 01/18/2023]
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Ljungberg MC, Ali YO, Zhu J, Wu CS, Oka K, Zhai RG, Lu HC. CREB-activity and nmnat2 transcription are down-regulated prior to neurodegeneration, while NMNAT2 over-expression is neuroprotective, in a mouse model of human tauopathy. Hum Mol Genet 2011; 21:251-67. [PMID: 22027994 DOI: 10.1093/hmg/ddr492] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Tauopathies, characterized by neurofibrillary tangles (NFTs) of phosphorylated tau proteins, are a group of neurodegenerative diseases, including frontotemporal dementia and both sporadic and familial Alzheimer's disease. Forebrain-specific over-expression of human tau(P301L), a mutation associated with frontotemporal dementia with parkinsonism linked to chromosome 17, in rTg4510 mice results in the formation of NFTs, learning and memory impairment and massive neuronal death. Here, we show that the mRNA and protein levels of NMNAT2 (nicotinamide mononucleotide adenylyltransferase 2), a recently identified survival factor for maintaining neuronal health in peripheral nerves, are reduced in rTg4510 mice prior to the onset of neurodegeneration or cognitive deficits. Two functional cAMP-response elements (CREs) were identified in the nmnat2 promoter region. Both the total amount of phospho-CRE binding protein (CREB) and the pCREB bound to nmnat2 CRE sites in the cortex and the hippocampus of rTg4510 mice are significantly reduced, suggesting that NMNAT2 is a direct target of CREB under physiological conditions and that tau(P301L) overexpression down-regulates CREB-mediated transcription. We found that over-expressing NMNAT2 or its homolog NMNAT1, but not NMNAT3, in rTg4510 hippocampi from 6 weeks of age using recombinant adeno-associated viral vectors significantly reduced neurodegeneration caused by tau(P301L) over-expression at 5 months of age. In summary, our studies strongly support a protective role of NMNAT2 in the mammalian central nervous system. Decreased endogenous NMNAT2 function caused by reduced CREB signaling during pathological insults may be one of underlying mechanisms for neuronal death in tauopathies.
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Affiliation(s)
- M Cecilia Ljungberg
- The Cain Foundation Laboratories, Jan and Dan Duncan Neurological Research Institute at Texas Children’s Hospital, Baylor College of Medicine, Houston, TX 77030, USA
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Xie M, Wang Q, Wu TH, Song SK, Sun SW. Delayed axonal degeneration in slow Wallerian degeneration mutant mice detected using diffusion tensor imaging. Neuroscience 2011; 197:339-47. [PMID: 21964470 DOI: 10.1016/j.neuroscience.2011.09.042] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Revised: 09/16/2011] [Accepted: 09/20/2011] [Indexed: 12/22/2022]
Abstract
Previous studies have shown the feasibility of using diffusion tensor imaging (DTI) as a noninvasive imaging modality to evaluate neurodegeneration in humans and animals. The axial and radial diffusivities derived from DTI were demonstrated to be sensitive markers for axonal and myelin damage, respectively. This study used DTI to evaluate optic nerve degeneration in wild-type and slow Wallerian degeneration (Wld(S)) mutant mice. Longitudinal DTI was performed on optic nerves following high intraocular pressure-induced transient retinal ischemia. The axial diffusivity of wild-type nerves decreased 30% (P<0.05) at 3 days and 40% (P<0.05) at 5-30 days after transient elevation of intraocular pressure. In contrast, the axial diffusivity of Wld(S) nerves did not change at 3 days; decreased by 20% (P<0.05) at 5 days, and continued to decrease by 30% (P<0.05) at 15 days and 40% (P<0.05) at 30 days after transient intraocular pressure elevation, suggesting delayed axonal damage in Wld(S) mice. Radial diffusivity increased 200% (P<0.05) at 15-30 days in the wild-type mice and 100% (P<0.05) at 30 days in the Wld(S) mice after transient intraocular pressure elevation, suggesting delayed myelin damage in Wld(S) mice. DTI detected damage was confirmed with immunohistochemistry using phosphorylated neurofilament and myelin basic protein for assessing axonal and myelin integrity, respectively. These findings support the use of DTI not only to evaluate the progression of neurodegeneration but also to noninvasively demonstrate Wld(S) mutation to delay the Wallerian degeneration.
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Affiliation(s)
- M Xie
- Department of Radiology, Washington University School of Medicine, St. Louis, MO, USA
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Zhu SS, Ren Y, Zhang M, Cao JQ, Yang Q, Li XY, Bai H, Jiang L, Jiang Q, He ZG, Chen Q. Wld(S) protects against peripheral neuropathy and retinopathy in an experimental model of diabetes in mice. Diabetologia 2011; 54:2440-50. [PMID: 21739347 DOI: 10.1007/s00125-011-2226-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2011] [Accepted: 05/31/2011] [Indexed: 10/18/2022]
Abstract
AIMS/HYPOTHESIS We aimed to evaluate the effect of the mutant Wld(S) (slow Wallerian degeneration; also known as Wld) gene in experimental diabetes on early experimental peripheral diabetic neuropathy and diabetic retinopathy. METHODS The experiments were performed in four groups of mice: wild-type (WT), streptozotocin (STZ)-induced diabetic WT, C57BL/Wld(S) and STZ-induced diabetic C57BL/Wld(S). In each group, intraperitoneal glucose and insulin tolerance tests were performed; blood glucose, glycated haemoglobin and serum insulin were monitored. These mice were also subjected to the following behavioural tests: grasping test, hot-plate test and von Frey aesthesiometer test. For some animals, sciatic-tibial motor nerve conduction velocity, tail sensory nerve conduction velocity and eye pattern electroretinogram were measured. At the end of the experiments, islets were isolated to detect glucose-stimulated insulin secretion, ATP content and extent of apoptosis. The NAD/NADH ratio in islets and retinas was evaluated. Surviving retinal ganglion cells were estimated by immunohistochemistry. RESULTS We found that the Wld(S) gene is expressed in islets and protects beta cells against multiple low doses of STZ by increasing the NAD/NADH ratio, maintaining the ATP concentration, and reducing apoptosis. Consistently, significantly higher insulin concentrations, lower blood glucose concentrations, and better glucose tolerance were observed in Wld(S) mice compared with WT mice after STZ treatment. Furthermore, Wld(S) alleviated abnormal sensory responses, nerve conduction, retina dysfunction and reduction of surviving retinal ganglion cells in STZ-induced diabetic models. CONCLUSIONS/INTERPRETATION We provide the first evidence that expression of the Wld(S) gene decreases beta cell destruction and preserves islet function in STZ-induced diabetes, thus revealing a novel protective strategy for diabetic models.
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Affiliation(s)
- S S Zhu
- Atherosclerosis Research Centre, Nanjing Medical University, 140 Hanzhong Road, Nanjing 210029, People's Republic of China
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Yoshioka H, Niizuma K, Katsu M, Sakata H, Okami N, Chan PH. Consistent injury to medium spiny neurons and white matter in the mouse striatum after prolonged transient global cerebral ischemia. J Neurotrauma 2011; 28:649-60. [PMID: 21309724 DOI: 10.1089/neu.2010.1662] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A reproducible transient global cerebral ischemia (tGCI) mouse model has not been fully established. Although striatal neurons and white matter are recognized to be vulnerable to ischemia, their injury after tGCI in mice has not been elucidated. The purpose of this study was to evaluate injuries to striatal neurons and white matter after tGCI in C57BL/6 mice, and to develop a reproducible tGCI model. Male C57BL/6 mice were subjected to tGCI by bilateral common carotid artery occlusion (BCCAO). Mice whose cortical cerebral blood flow after BCCAO decreased to less than 13% of the pre-ischemic value were used. Histological analysis showed that at 3 days after 22 min of BCCAO, striatal neurons were injured more consistently than those in other brain regions. Quantitative analysis of cytochrome c release into the cytosol and DNA fragmentation in the striatum showed consistent injury to the striatum. Immunohistochemistry and Western blot analysis revealed that DARPP-32-positive medium spiny neurons, the majority of striatal neurons, were the most vulnerable among the striatal neuronal subpopulations. The striatum (especially medium spiny neurons) was susceptible to oxidative stress after tGCI, which is probably one of the mechanisms of vulnerability. SMI-32 immunostaining showed that white matter in the striatum was also consistently injured 3 days after 22 min of BCCAO. We thus suggest that this is a tGCI model using C57BL/6 mice that consistently produces neuronal and white matter injury in the striatum by a simple technique. This model can be highly applicable for elucidating molecular mechanisms in the brain after global ischemia.
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Affiliation(s)
- Hideyuki Yoshioka
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California 94305-5487, USA
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Yoshioka H, Niizuma K, Katsu M, Okami N, Sakata H, Kim GS, Narasimhan P, Chan PH. NADPH oxidase mediates striatal neuronal injury after transient global cerebral ischemia. J Cereb Blood Flow Metab 2011; 31:868-80. [PMID: 20859296 PMCID: PMC3010524 DOI: 10.1038/jcbfm.2010.166] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Medium spiny neurons (MSNs) constitute most of the striatal neurons and are known to be vulnerable to ischemia; however, the mechanisms of the vulnerability remain unclear. Activated forms of nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase (NOX), which require interaction between cytosolic and membrane-bound subunits, are among the major sources of superoxide in the central nervous system. Although increasing evidence suggests that NOX has important roles in neurodegenerative diseases, its roles in MSN injury after transient global cerebral ischemia (tGCI) have not been elucidated. To clarify this issue, C57BL/6 mice were subjected to tGCI by bilateral common carotid artery occlusion for 22 minutes. Western blot analysis revealed upregulation of NOX subunits and recruitment of cytosolic subunits to the cell membrane at early (3 to 6 hours) and late (72 hours) phases after tGCI. Taken together with immunofluorescent studies, this activation arose in MSNs and endothelial cells at the early phase, and in reactive microglia at the late phase. Pharmacological and genetic inhibition of NOX attenuated oxidative injury, microglial activation, and MSN death after tGCI. These findings suggest that NOX has pivotal roles in MSN injury after tGCI and could be a therapeutic target for brain ischemia.
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Affiliation(s)
- Hideyuki Yoshioka
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, California 94305-5487, USA
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Wright AK, Wishart TM, Ingham CA, Gillingwater TH. Synaptic protection in the brain of WldS mice occurs independently of age but is sensitive to gene-dose. PLoS One 2010; 5:e15108. [PMID: 21124744 PMCID: PMC2993971 DOI: 10.1371/journal.pone.0015108] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 10/21/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Disruption of synaptic connectivity is a significant early event in many neurodegenerative conditions affecting the aging CNS, including Alzheimer's disease and Parkinson's disease. Therapeutic approaches that protect synapses from degeneration in the aging brain offer the potential to slow or halt the progression of such conditions. A range of animal models expressing the slow Wallerian Degeneration (Wld(S)) gene show robust neuroprotection of synapses and axons from a wide variety of traumatic and genetic neurodegenerative stimuli in both the central and peripheral nervous systems, raising that possibility that Wld(S) may be useful as a neuroprotective agent in diseases with synaptic pathology. However, previous studies of neuromuscular junctions revealed significant negative effects of increasing age and positive effects of gene-dose on Wld(S)-mediated synaptic protection in the peripheral nervous system, raising doubts as to whether Wld(S) is capable of directly conferring synapse protection in the aging brain. METHODOLOGY/PRINCIPAL FINDINGS We examined the influence of age and gene-dose on synaptic protection in the brain of mice expressing the Wld(S) gene using an established cortical lesion model to induce synaptic degeneration in the striatum. Synaptic protection was found to be sensitive to Wld(S) gene-dose, with heterozygous Wld(S) mice showing approximately half the level of protection observed in homozygous Wld(S) mice. Increasing age had no influence on levels of synaptic protection. In contrast to previous findings in the periphery, synapses in the brain of old Wld(S) mice were just as strongly protected as those in young mice. CONCLUSIONS/SIGNIFICANCE Our study demonstrates that Wld(S)-mediated synaptic protection in the CNS occurs independently of age, but is sensitive to gene dose. This suggests that the Wld(S) gene, and in particular its downstream endogenous effector pathways, may be potentially useful therapeutic agents for conferring synaptic protection in the aging brain.
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Affiliation(s)
- Ann K. Wright
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas M. Wishart
- Euan MacDonald Centre for Motor Neurone Disease Research, University of Edinburgh, Edinburgh, United Kingdom
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh, United Kingdom
| | - Cali A. Ingham
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - 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
- * E-mail:
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Sheline CT, Cai AL, Zhu J, Shi C. Serum or target deprivation-induced neuronal death causes oxidative neuronal accumulation of Zn2+ and loss of NAD+. Eur J Neurosci 2010; 32:894-904. [PMID: 20722716 DOI: 10.1111/j.1460-9568.2010.07372.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Trophic deprivation-mediated neuronal death is important during development, after acute brain or nerve trauma, and in neurodegeneration. Serum deprivation (SD) approximates trophic deprivation in vitro, and an in vivo model is provided by neuronal death in the mouse dorsal lateral geniculate nucleus (LGNd) after ablation of the visual cortex (VCA). Oxidant-induced intracellular Zn(2+) release ([Zn(2+) ](i) ) from metallothionein-3 (MT-III), mitochondria or 'protein Zn(2+) ', was implicated in trophic deprivation neurotoxicity. We have previously shown that neurotoxicity of extracellular Zn(2+) required entry, increased [Zn(2+) ](i) , and reduction of NAD(+) and ATP levels causing inhibition of glycolysis and cellular metabolism. Exogenous NAD(+) and sirtuin inhibition attenuated Zn(2+) neurotoxicity. Here we show that: (1) Zn(2+) is released intracellularly after oxidant and SD injuries, and that sensitivity to these injuries is proportional to neuronal Zn(2+) content; (2) NAD(+) loss is involved - restoration of NAD(+) using exogenous NAD(+) , pyruvate or nicotinamide attenuated these injuries, and potentiation of NAD(+) loss potentiated injury; (3) neurons from genetically modified mouse strains which reduce intracellular Zn(2+) content (MT-III knockout), reduce NAD(+) catabolism (PARP-1 knockout) or increase expression of an NAD(+) synthetic enzyme (Wld(s) ) each had attenuated SD and oxidant neurotoxicities; (4) sirtuin inhibitors attenuated and sirtuin activators potentiated these neurotoxicities; (5) visual cortex ablation (VCA) induces Zn(2+) staining and death only in ipsilateral LGNd neurons, and a 1 mg/kg Zn(2+) diet attenuated injury; and finally (6) NAD(+) synthesis and levels are involved given that LGNd neuronal death after VCA was dramatically reduced in Wld(s) animals, and by intraperitoneal pyruvate or nicotinamide. Zn(2+) toxicity is involved in serum and trophic deprivation-induced neuronal death.
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Affiliation(s)
- Christian T Sheline
- Department of Ophthalmology and the Neuroscience Center of Excellence, LSU Health Sciences Center, 2020 Gravier Street, Suite D, New Orleans, LA 70112, USA.
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Beirowski B, Morreale G, Conforti L, Mazzola F, Di Stefano M, Wilbrey A, Babetto E, Janeckova L, Magni G, Coleman MP. WldS can delay Wallerian degeneration in mice when interaction with valosin-containing protein is weakened. Neuroscience 2009; 166:201-11. [PMID: 20018231 DOI: 10.1016/j.neuroscience.2009.12.024] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Revised: 12/08/2009] [Accepted: 12/10/2009] [Indexed: 10/20/2022]
Abstract
Axon degeneration is an early event in many neurodegenerative disorders. In some, the mechanism is related to injury-induced Wallerian degeneration, a proactive death program that can be strongly delayed by the neuroprotective slow Wallerian degeneration protein (Wld(S)) protein. Thus, it is important to understand the Wallerian degeneration mechanism and how Wld(S) blocks it. Wld(S) location is influenced by binding to valosin-containing protein (VCP), an essential protein for many cellular processes including membrane fusion and endoplasmic reticulum-associated degradation. In mice, the N-terminal 16 amino acids (N16), which mediate VCP binding, are essential for Wld(S) to protect axons, a role which another VCP binding sequence can substitute. In Drosophila, the Wld(S) phenotype is weakened by a similar N-terminal truncation and by knocking down the VCP homologue ter94. Neither null nor floxed VCP mice are viable so it is difficult to confirm the requirement for VCP binding in mammals in vivo. However, the hypothesis can be tested further by introducing a Wld(S) missense mutation, altering its affinity for VCP but minimizing the risk of disturbing other aspects of its structure or function. We introduced the R10A mutation, which weakens VCP binding in vitro, and expressed it in transgenic mice. R10AWld(S) fails to co-immunoprecipitate VCP from mouse brain, and only occasionally and faintly accumulates in nuclear foci for which VCP binding is necessary but not sufficient. Surprisingly however, axon protection remains robust and indistinguishable from that in spontaneous Wld(S) mice. We suggest that either N16 has an additional, VCP-independent function in mammals, or that the phenotype requires only weak VCP binding which may be driven forwards in vivo by the high VCP concentration.
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Affiliation(s)
- B Beirowski
- The Babraham Institute, Babraham Research Campus, Laboratory of Molecular Signalling, Cambridge CB22 3AT, UK.
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Wishart TM, Brownstein DG, Thomson D, Tabakova AM, Boothe KM, Tsao JW, Gillingwater TH. Expression of the neuroprotective slow Wallerian degeneration (WldS) gene in non-neuronal tissues. BMC Neurosci 2009; 10:148. [PMID: 20015399 PMCID: PMC2801506 DOI: 10.1186/1471-2202-10-148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Accepted: 12/16/2009] [Indexed: 02/07/2023] Open
Abstract
Background The slow Wallerian Degeneration (WldS) gene specifically protects axonal and synaptic compartments of neurons from a wide variety of degeneration-inducing stimuli, including; traumatic injury, Parkinson's disease, demyelinating neuropathies, some forms of motor neuron disease and global cerebral ischemia. The WldS gene encodes a novel Ube4b-Nmnat1 chimeric protein (WldS protein) that is responsible for conferring the neuroprotective phenotype. How the chimeric WldS protein confers neuroprotection remains controversial, but several studies have shown that expression in neurons in vivo and in vitro modifies key cellular pathways, including; NAD biosynthesis, ubiquitination, the mitochondrial proteome, cell cycle status and cell stress. Whether similar changes are induced in non-neuronal tissue and organs at a basal level in vivo remains to be determined. This may be of particular importance for the development and application of neuroprotective therapeutic strategies based around WldS-mediated pathways designed for use in human patients. Results We have undertaken a detailed analysis of non-neuronal WldS expression in WldS mice, alongside gravimetric and histological analyses, to examine the influence of WldS expression in non-neuronal tissues. We show that expression of WldS RNA and protein are not restricted to neuronal tissue, but that the relative RNA and protein expression levels rarely correlate in these non-neuronal tissues. We show that WldS mice have normal body weight and growth characteristics as well as gravimetrically and histologically normal organs, regardless of WldS protein levels. Finally, we demonstrate that previously reported WldS-induced changes in cell cycle and cell stress status are neuronal-specific, not recapitulated in non-neuronal tissues at a basal level. Conclusions We conclude that expression of WldS protein has no adverse effects on non-neuronal tissue at a basal level in vivo, supporting the possibility of its safe use in future therapeutic strategies targeting axonal and/or synaptic compartments in patients with neurodegenerative disease. Future experiments determining whether WldS protein can modify responses to injury in non-neuronal tissue are now required.
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Affiliation(s)
- Thomas M Wishart
- Centre for Integrative Physiology & Euan MacDonald Centre for Motor Neuron Disease Research, University of Edinburgh Medical School, Edinburgh EH89XD, UK
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The role of Sirt1: at the crossroad between promotion of longevity and protection against Alzheimer's disease neuropathology. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2009; 1804:1690-4. [PMID: 19945548 DOI: 10.1016/j.bbapap.2009.11.015] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 11/12/2009] [Accepted: 11/15/2009] [Indexed: 11/24/2022]
Abstract
Sirt1, a mammalian member of the sirtuin gene family, holds great potential for promoting longevity, preventing against disease and increasing cell survival. For example, studies suggest that the beneficial impact of caloric restriction in promoting longevity and cellular function may be mediated, in part, by Sirt1 through mechanisms involving PGC-1alpha, which plays important role in the regulation of cellular metabolism and inflammatory and antioxidant responses. Sirt1 may also interfere with mechanisms implicated in pathological disorders. We will present recent evidence indicating that Sirt1 may protect against Alzheimer's disease by interfering with the generation of beta-amyloid peptides. We will discuss Sirt1 as a potential novel target, in addition to the development of Sirt1 activators for the prevention and treatment of Alzheimer's disease.
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Wei G, Doré S. Importance of normothermia control in investigating delayed neuronal injury in a mouse global ischemia model. J Neurosci Methods 2009; 185:230-5. [PMID: 19815029 DOI: 10.1016/j.jneumeth.2009.09.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 09/28/2009] [Accepted: 09/28/2009] [Indexed: 01/08/2023]
Abstract
This study aims to establish a mouse global cerebral ischemia model in which the physiological parameter measurements and neuronal injury evaluations are conducted in the same group of animals and to identify the effect of post-ischemic core temperature (CT) on the outcome of neuronal injury. Global ischemia was induced by 12-min bilateral common carotid artery occlusion followed by 7 days of reperfusion in C57BL/6 mice. Immediately after occlusion, mice were randomly assigned to be kept in environments of different temperatures [25 degrees C (room temperature, group 1), 33-34 degrees C for 2h (group 2), and 33-34 degrees C for 24h (group 3)] before being returned to their home cages. We found that in group 1, CT declined to approximately 32 degrees C after ischemia and then recovered at 24h post-ischemia; in group 2, CT remained at the pre-ischemia level during the first 2h, declined after the mice were returned to room temperature, and recovered at 24h post-ischemia; and in group 3, CT remained constant at the pre-ischemia level throughout the reperfusion period. The number of surviving neurons in a sector of the hippocampal CA1 region was significantly lower in all ischemic groups than in the sham controls, but the number was significantly higher in group 1 than that in groups 2 or 3 (P<0.05). We observed that CT declines initially but recovers spontaneously at 24h post-ischemia. Early post-ischemic hypothermia impacts the delayed neuronal injury, suggesting that tight temperature control immediately following ischemia is important to obtain the most reproducible neuronal damage in mouse models of cerebral global ischemia.
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Affiliation(s)
- G Wei
- Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
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Zhai RG, Rizzi M, Garavaglia S. Nicotinamide/nicotinic acid mononucleotide adenylyltransferase, new insights into an ancient enzyme. Cell Mol Life Sci 2009; 66:2805-18. [PMID: 19448972 PMCID: PMC11115848 DOI: 10.1007/s00018-009-0047-x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2009] [Revised: 04/16/2009] [Accepted: 04/28/2009] [Indexed: 12/14/2022]
Abstract
Nicotinamide/nicotinic acid mononucleotide adenylyltransferase (NMNAT) has long been known as the master enzyme in NAD biosynthesis in living organisms. A burst of investigations on NMNAT, going beyond enzymology, have paralleled increasing discoveries of key roles played by NAD homeostasis in a number or patho-physiological conditions. The availability of in-depth kinetics and structural enzymology analyses carried out on NMNATs from different organisms offer a powerful tool for uncovering fascinating evolutionary relationships. On the other hand, additional functions featuring NMNAT have emerged from investigations aimed at unraveling the molecular mechanisms responsible for complex biological phenomena such as neurodegeneration. NMNAT appears to be a multifunctional protein that sits both at the core of central metabolism and at a crossroads of multiple cellular processes. The resultant wealth of biochemical data has built a robust framework upon which design of NMNAT activators, inhibitors or enzyme variants of potential medical interest can be based.
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Affiliation(s)
- Rong Grace Zhai
- Department of Molecular and Cellular Pharmacology, Neuroscience Center, Miller School of Medicine, University of Miami, Miami, FL 33136 USA
| | - Menico Rizzi
- DiSCAFF, University of Piemonte Orientale “A. Avogadro”, Via Bovio, 6, 28100 Novara, Italy
| | - Silvia Garavaglia
- DiSCAFF, University of Piemonte Orientale “A. Avogadro”, Via Bovio, 6, 28100 Novara, Italy
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Kielar C, Wishart TM, Palmer A, Dihanich S, Wong AM, Macauley SL, Chan CH, Sands MS, Pearce DA, Cooper JD, Gillingwater TH. Molecular correlates of axonal and synaptic pathology in mouse models of Batten disease. Hum Mol Genet 2009; 18:4066-80. [PMID: 19640925 PMCID: PMC2758138 DOI: 10.1093/hmg/ddp355] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Neuronal ceroid lipofuscinoses (NCLs; Batten disease) are collectively the most frequent autosomal-recessive neurodegenerative disease of childhood, but the underlying cellular and molecular mechanisms remain unclear. Several lines of evidence have highlighted the important role that non-somatic compartments of neurons (axons and synapses) play in the instigation and progression of NCL pathogenesis. Here, we report a progressive breakdown of axons and synapses in the brains of two different mouse models of NCL: Ppt1−/− model of infantile NCL and Cln6nclf model of variant late-infantile NCL. Synaptic pathology was evident in the thalamus and cortex of these mice, but occurred much earlier within the thalamus. Quantitative comparisons of expression levels for a subset of proteins previously implicated in regulation of axonal and synaptic vulnerability revealed changes in proteins involved with synaptic function/stability and cell-cycle regulation in both strains of NCL mice. Protein expression changes were present at pre/early-symptomatic stages, occurring in advance of morphologically detectable synaptic or axonal pathology and again displayed regional selectivity, occurring first within the thalamus and only later in the cortex. Although significant differences in individual protein expression profiles existed between the two NCL models studied, 2 of the 15 proteins examined (VDAC1 and Pttg1) displayed robust and significant changes at pre/early-symptomatic time-points in both models. Our study demonstrates that synapses and axons are important early pathological targets in the NCLs and has identified two proteins, VDAC1 and Pttg1, with the potential for use as in vivo biomarkers of pre/early-symptomatic axonal and synaptic vulnerability in the NCLs.
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Affiliation(s)
- Catherine Kielar
- Department of Neuroscience, Centre for the Cellular Basis of Behaviour, Institute of Psychiatry, King's College London, London SE5 9NU, UK
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Prion disease development in slow Wallerian degeneration (Wld(S)) mice. Neurosci Lett 2009; 456:93-8. [PMID: 19429141 DOI: 10.1016/j.neulet.2009.03.089] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 03/26/2009] [Accepted: 03/27/2009] [Indexed: 11/22/2022]
Abstract
Axon destruction represents one aspect of prion disease-associated neurodegeneration. We characterized here the scrapie infection of Wld(S)-mice in comparison to wild-type C57Bl/6 controls to determine whether mechanisms involved in Wallerian degeneration contribute to disease development in this murine model system. The Wld(S) mutation had neither an effect on survival times, nor on typical hallmarks of a prion infection like deposition of misfolded PrP(Sc) and glia activation. At the ultrastructural level, axonal damage like loss of axoplasms and disintegration of myelin sheaths was evident. Moreover, lysosomes accumulated in neuronal cell bodies. These alterations occured however similarly in Wld(S)- and wild-type mice. In conclusion, it appears unlikely that axonal damage of the kind, which is slowed down in Wld(S)-mice, contributes significantly to disease progression. These findings distinguish the neurodegeneration occuring in this prion model from chronic neurodegenerative diseases, in which the Wld(S)-mutation provides axon protection and greatly improves the clinical outcome.
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Kariya S, Mauricio R, Dai Y, Monani UR. The neuroprotective factor Wld(s) fails to mitigate distal axonal and neuromuscular junction (NMJ) defects in mouse models of spinal muscular atrophy. Neurosci Lett 2008; 449:246-51. [PMID: 19010394 DOI: 10.1016/j.neulet.2008.10.107] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 10/21/2008] [Accepted: 10/27/2008] [Indexed: 01/18/2023]
Abstract
Spinal muscular atrophy (SMA) is a common autosomal recessive neurodegenerative disorder in humans. Amongst the earliest signs of neurodegeneration are severe and progressive defects of the neuromuscular synapse. These defects, characterized by poor terminal arborization and immature motor endplates, presumably result in a loss of functional synapses. The slow Wallerian degeneration (Wld(s)) mutation in rodents has been shown to have a protective effect on mouse models of motor neuron disease by retarding axonal die-back and preventing neuromuscular synapse loss. In this study we tested the effects of the Wld(s) mutation on the disease phenotype of SMA model mice. Consistent with previous reports, the mutation slows axon and neuromuscular synapse loss following nerve injury in wild-type as well as in SMA mice. However, the synaptic defects found in severely affected SMA patients and model mice persist in the double (Wld(s);SMA) mutants. No delay in disease onset was observed and survival was not significantly altered. Finally, Wld(s) had no effect on the striking phrenic nerve projection defects that we discovered in SMA model mice. Our results indicate that the reported protective effects of Wld(s) are insufficient to mitigate the neuromuscular phenotype due to reduced SMN protein, and that the mechanisms responsible for distal defects of the motor unit in SMA are unlikely to be similar to those causing neurodegeneration in genetic mutants such as the pmn mouse which is partially rescued by the Wld(s) protein.
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Affiliation(s)
- Shingo Kariya
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
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Wei G, Kibler KK, Koehler RC, Maruyama T, Narumiya S, Doré S. Prostacyclin receptor deletion aggravates hippocampal neuronal loss after bilateral common carotid artery occlusion in mouse. Neuroscience 2008; 156:1111-7. [PMID: 18790018 DOI: 10.1016/j.neuroscience.2008.07.073] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 07/11/2008] [Accepted: 07/18/2008] [Indexed: 11/20/2022]
Abstract
Transient global cerebral ischemia causes delayed neuronal death in the hippocampal CA1 region. It also induces an increase in cyclooxygenase 2 (COX-2), which generates several metabolites of arachidonic acid, known as prostanoids, including prostacyclin (PGI(2)). To determine the role of the PGI(2) receptor (IP) in post-ischemic delayed cell death, wild-type and IP knockout (IP(-/-)) C57Bl/6 mice were subjected to 12-min bilateral common carotid artery occlusion or sham surgery, followed by 7 days of reperfusion. In the sham-operated mice, no statistical difference in CA1 hippocampal neuronal density was observed between the wild-type (2836+/-18/mm(2)) and IP(-/-) (2793+/-43/mm(2)) mice. Interestingly, in animals subjected to ischemia, surviving neuronal density in wild-type mice decreased to 50.5+/-7.9% and that of IP(-/-) mice decreased to 23.0+/-4.5% of their respective sham-operated controls (P<0.05). The results establish a role for the IP receptor in protecting pyramidal hippocampal neurons after this global ischemic model and suggest that IP receptor agonists could be developed to prevent delayed pyramidal neuronal cell death.
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Affiliation(s)
- G Wei
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
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Wishart TM, Pemberton HN, James SR, McCabe CJ, Gillingwater TH. Modified cell cycle status in a mouse model of altered neuronal vulnerability (slow Wallerian degeneration; Wlds). Genome Biol 2008; 9:R101. [PMID: 18570652 PMCID: PMC2481432 DOI: 10.1186/gb-2008-9-6-r101] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 06/12/2008] [Accepted: 06/20/2008] [Indexed: 12/03/2022] Open
Abstract
Profiling of gene expression changes in mice harbouring the neurodegenerative Wlds mutation shows a strong correlation between changes in cell cycle pathways and altered vulnerability of terminally differentiated neurons. Background Altered neuronal vulnerability underlies many diseases of the human nervous system, resulting in degeneration and loss of neurons. The neuroprotective slow Wallerian degeneration (Wlds) mutation delays degeneration in axonal and synaptic compartments of neurons following a wide range of traumatic and disease-inducing stimuli, providing a powerful experimental tool with which to investigate modulation of neuronal vulnerability. Although the mechanisms through which Wlds confers neuroprotection remain unclear, a diverse range of downstream modifications, incorporating several genes/pathways, have been implicated. These include the following: elevated nicotinamide adenine dinucleotide (NAD) levels associated with nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1; a part of the chimeric Wlds gene); altered mRNA expression levels of genes such as pituitary tumor transforming gene 1 (Pttg1); changes in the location/activity of the ubiquitin-proteasome machinery via binding to valosin-containing protein (VCP/p97); and modified synaptic expression of proteins such as ubiquitin-activating enzyme E1 (Ube1). Results Wlds expression in mouse cerebellum and HEK293 cells induced robust increases in a broad spectrum of cell cycle-related genes. Both NAD-dependent and Pttg1-dependent pathways were responsible for mediating different subsets of these alterations, also incorporating changes in VCP/p97 localization and Ube1 expression. Cell proliferation rates were not modified by Wlds, suggesting that later mitotic phases of the cell cycle remained unaltered. We also demonstrate that Wlds concurrently altered endogenous cell stress pathways. Conclusion We report a novel cellular phenotype in cells with altered neuronal vulnerability. We show that previous reports of diverse changes occurring downstream from Wlds expression converge upon modifications in cell cycle status. These data suggest a strong correlation between modified cell cycle pathways and altered vulnerability of axonal and synaptic compartments in postmitotic, terminally differentiated neurons.
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Affiliation(s)
- Thomas M Wishart
- Centre for Integrative Physiology, University of Edinburgh Medical School, Edinburgh, UK
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Press C, Milbrandt J. Nmnat delays axonal degeneration caused by mitochondrial and oxidative stress. J Neurosci 2008; 28:4861-71. [PMID: 18463239 PMCID: PMC2678678 DOI: 10.1523/jneurosci.0525-08.2008] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 03/13/2008] [Accepted: 03/26/2008] [Indexed: 12/15/2022] Open
Abstract
Axonal degeneration is a prominent feature of many neurological disorders that are associated with mitochondrial dysfunction, including Parkinson's disease, motor neuron disease, and inherited peripheral neuropathies. Studies of the Wld(s) mutant mouse, which undergoes delayed Wallerian degeneration in response to axonal injury, suggest that axonal degeneration is an active process. Wld(s) mice also have slower axonal degeneration and disease progression in numerous models of neurodegenerative disease. The Wld(s) mutation results in the production of a chimeric protein that contains the full-length coding sequence of nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1), which alone is sufficient for axonal protection in vitro. To test the effects of increased Nmnat expression on axonal degeneration induced by mitochondrial dysfunction, we examined dorsal root ganglion (DRG) neurons treated with rotenone. Rotenone induced profound axonal degeneration in DRG neurons; however, this degeneration was delayed by expression of Nmnat. Nmnat-mediated protection resulted in decreased axonal accumulation and sensitivity to reactive oxygen species (ROS) but did not affect the change in the rate of rotenone-induced loss in neuronal ATP. Nmnat also prevented axonal degeneration caused by exposure to exogenous oxidants and reduced the level of axonal ROS after treatment with vincristine, further supporting the idea that Nmnat promotes axonal protection by mitigating the effects of ROS.
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Affiliation(s)
- Craig Press
- Department of Pathology, Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Jeffrey Milbrandt
- Department of Pathology, Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, Missouri 63110
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Zhai RG, Zhang F, Hiesinger PR, Cao Y, Haueter CM, Bellen HJ. NAD synthase NMNAT acts as a chaperone to protect against neurodegeneration. Nature 2008; 452:887-91. [PMID: 18344983 DOI: 10.1038/nature06721] [Citation(s) in RCA: 153] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 01/16/2008] [Indexed: 11/09/2022]
Abstract
Neurodegeneration can be triggered by genetic or environmental factors. Although the precise cause is often unknown, many neurodegenerative diseases share common features such as protein aggregation and age dependence. Recent studies in Drosophila have uncovered protective effects of NAD synthase nicotinamide mononucleotide adenylyltransferase (NMNAT) against activity-induced neurodegeneration and injury-induced axonal degeneration. Here we show that NMNAT overexpression can also protect against spinocerebellar ataxia 1 (SCA1)-induced neurodegeneration, suggesting a general neuroprotective function of NMNAT. It protects against neurodegeneration partly through a proteasome-mediated pathway in a manner similar to heat-shock protein 70 (Hsp70). NMNAT displays chaperone function both in biochemical assays and cultured cells, and it shares significant structural similarity with known chaperones. Furthermore, it is upregulated in the brain upon overexpression of poly-glutamine expanded protein and recruited with the chaperone Hsp70 into protein aggregates. Our results implicate NMNAT as a stress-response protein that acts as a chaperone for neuronal maintenance and protection. Our studies provide an entry point for understanding how normal neurons maintain activity, and offer clues for the common mechanisms underlying different neurodegenerative conditions.
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Affiliation(s)
- R Grace Zhai
- Department of Molecular and Cellular Pharmacology, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA.
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Wishart TM, Macdonald SH, Chen PE, Shipston MJ, Coleman MP, Gillingwater TH, Ribchester RR. Design of a novel quantitative PCR (QPCR)-based protocol for genotyping mice carrying the neuroprotective Wallerian degeneration slow (Wlds) gene. Mol Neurodegener 2007; 2:21. [PMID: 17971231 PMCID: PMC2147001 DOI: 10.1186/1750-1326-2-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Accepted: 10/30/2007] [Indexed: 11/18/2022] Open
Abstract
Background Mice carrying the spontaneous genetic mutation known as Wallerian degeneration slow (Wlds) have a unique neuroprotective phenotype, where axonal and synaptic compartments of neurons are protected from degeneration following a wide variety of physical, toxic and inherited disease-inducing stimuli. This remarkable phenotype has been shown to delay onset and progression in several mouse models of neurodegenerative disease, suggesting that Wlds-mediated neuroprotection may assist in the identification of novel therapeutic targets. As a result, cross-breeding of Wlds mice with mouse models of neurodegenerative diseases is used increasingly to understand the roles of axon and synapse degeneration in disease. However, the phenotype shows strong gene-dose dependence so it is important to distinguish offspring that are homozygous or heterozygous for the mutation. Since the Wlds mutation comprises a triplication of a region already present in the mouse genome, the most stringent way to quantify the number of mutant Wlds alleles is using copy number. Current approaches to genotype Wlds mice are based on either Southern blots or pulsed field gel electrophoresis, neither of which are as rapid or efficient as quantitative PCR (QPCR). Results We have developed a rapid, robust and efficient genotyping method for Wlds using QPCR. This approach differentiates, based on copy number, homozygous and heterozygous Wlds mice from wild-type mice and each other. We show that this approach can be used to genotype mice carrying the spontaneous Wlds mutation as well as animals expressing the Wlds transgene. Conclusion We have developed a QPCR genotyping method that permits rapid and effective genotyping of Wlds copy number. This technique will be of particular benefit in studies where Wlds mice are cross-bred with other mouse models of neurodegenerative disease in order to understand the neuroprotective processes conferred by the Wlds mutation.
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Affiliation(s)
- Thomas M Wishart
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, UK.
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Axon & dendrite degeneration: its mechanisms and protective experimental paradigms. Neurochem Int 2007; 52:751-60. [PMID: 18029056 DOI: 10.1016/j.neuint.2007.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2007] [Revised: 09/01/2007] [Accepted: 09/07/2007] [Indexed: 12/13/2022]
Abstract
Accumulating evidence suggests that axon and dendrite (or neurite) degeneration both in vivo and in vitro requires self-destructive programs independent of cell death programs to segregate neurite degeneration from cell soma demise. This review will deal with the mechanisms of neurite degeneration caused by several experimental paradigms including trophic factor deprivation and Wallerian degeneration as well as those under pathological conditions. The involvement of autophagy and mitochondrial dysfunction is emphasized in these mechanisms. The mechanisms through which protective agents including the Wld(s) protein rescue neurites from degeneration or fail to do so will be discussed.
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Bridge KE, Berg N, Adalbert R, Babetto E, Dias T, Spillantini MG, Ribchester RR, Coleman MP. Late onset distal axonal swelling in YFP-H transgenic mice. Neurobiol Aging 2007; 30:309-21. [PMID: 17658198 DOI: 10.1016/j.neurobiolaging.2007.06.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Revised: 06/03/2007] [Accepted: 06/07/2007] [Indexed: 11/19/2022]
Abstract
Axonal swellings, or spheroids, are a feature of central nervous system (CNS) axon degeneration during normal aging and in many disorders. The direct cause and mechanism are unknown. The use of transgenic mouse line YFP-H, which expresses yellow-fluorescent protein (YFP) in a subset of neurons, greatly facilitates longitudinal imaging and live imaging of axonal swellings, but it has not been established whether long-term expression of YFP itself contributes to axonal swelling. Using conventional methods to compare YFP-H mice with their YFP negative littermates, we found an age-related increase in swellings in discrete CNS regions in both genotypes, but the presence of YFP caused significantly more swellings in mice aged 8 months or over. Increased swelling was found in gracile tract, gracile nucleus and dorsal roots but not in lateral columns, olfactory bulb, motor cortex, ventral roots or peripheral nerve. Thus, long-term expression of YFP accelerates age-related axonal swelling in some axons and data reliant on the presence of YFP in these CNS regions in older animals needs to be interpreted carefully. The ability of a foreign protein to exacerbate age-related axon pathology is an important clue to the mechanisms by which such pathology can arise.
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Affiliation(s)
- Katherine E Bridge
- Laboratory of Molecular Signalling, Babraham Institute, Babraham, Cambridge CB22 3AT, UK
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Wishart TM, Paterson JM, Short DM, Meredith S, Robertson KA, Sutherland C, Cousin MA, Dutia MB, Gillingwater TH. Differential proteomics analysis of synaptic proteins identifies potential cellular targets and protein mediators of synaptic neuroprotection conferred by the slow Wallerian degeneration (Wlds) gene. Mol Cell Proteomics 2007; 6:1318-30. [PMID: 17470424 PMCID: PMC2225590 DOI: 10.1074/mcp.m600457-mcp200] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Non-somatic synaptic and axonal compartments of neurons are primary pathological targets in many neurodegenerative conditions, ranging from Alzheimer disease through to motor neuron disease. Axons and synapses are protected from degeneration by the slow Wallerian degeneration (Wld(s)) gene. Significantly the molecular mechanisms through which this spontaneous genetic mutation delays degeneration remain controversial, and the downstream protein targets of Wld(s) resident in non-somatic compartments remain unknown. In this study we used differential proteomics analysis to identify proteins whose expression levels were significantly altered in isolated synaptic preparations from the striatum of Wld(s) mice. Eight of the 16 proteins we identified as having modified expression levels in Wld(s) synapses are known regulators of mitochondrial stability and degeneration (including VDAC1, Aralar1, and mitofilin). Subsequent analyses demonstrated that other key mitochondrial proteins, not identified in our initial screen, are also modified in Wld(s) synapses. Of the non-mitochondrial proteins identified, several have been implicated in neurodegenerative diseases where synapses and axons are primary pathological targets (including DRP-2 and Rab GDP dissociation inhibitor beta). In addition, we show that downstream protein changes can be identified in pathways corresponding to both Ube4b (including UBE1) and Nmnat1 (including VDAC1 and Aralar1) components of the chimeric Wld(s) gene, suggesting that full-length Wld(s) protein is required to elicit maximal changes in synaptic proteins. We conclude that altered mitochondrial responses to degenerative stimuli are likely to play an important role in the neuroprotective Wld(s) phenotype and that targeting proteins identified in the current study may lead to novel therapies for the treatment of neurodegenerative diseases in humans.
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Affiliation(s)
- Thomas M. Wishart
- Centre for Integrative Physiology, University of Edinburgh Medical School, Edinburgh EH8 9XD, UK
- Centre for Neuroscience Research, University of Edinburgh Medical School, Edinburgh EH8 9XD, UK
| | - Janet M. Paterson
- Centre for Integrative Physiology, University of Edinburgh Medical School, Edinburgh EH8 9XD, UK
| | - Duncan M. Short
- Astellas CNS Research in Edinburgh, The Chancellor's Building, New Royal Infirmary, Little France Crescent, Edinburgh EH16 4SB, UK
| | - Sara Meredith
- Centre for Integrative Physiology, University of Edinburgh Medical School, Edinburgh EH8 9XD, UK
| | - Kevin A. Robertson
- Division of Pathway Medicine, University of Edinburgh, The Chancellor's Building, New Royal Infirmary, Little France Crescent, Edinburgh EH16 4SB, UK
| | - Calum Sutherland
- Pathology and Neurosciences, University of Dundee, Dundee DD1 9SY, UK
| | - Michael A. Cousin
- Centre for Integrative Physiology, University of Edinburgh Medical School, Edinburgh EH8 9XD, UK
- Centre for Neuroscience Research, University of Edinburgh Medical School, Edinburgh EH8 9XD, UK
| | - Mayank B. Dutia
- Centre for Integrative Physiology, University of Edinburgh Medical School, Edinburgh EH8 9XD, UK
| | - Thomas H. Gillingwater
- Centre for Integrative Physiology, University of Edinburgh Medical School, Edinburgh EH8 9XD, UK
- Centre for Neuroscience Research, University of Edinburgh Medical School, Edinburgh EH8 9XD, UK
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Cho KO, Kim SK, Cho YJ, Sung KW, Kim SY. Regional differences in the neuroprotective effect of minocycline in a mouse model of global forebrain ischemia. Life Sci 2007; 80:2030-5. [PMID: 17408699 DOI: 10.1016/j.lfs.2007.03.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2006] [Revised: 02/16/2007] [Accepted: 03/05/2007] [Indexed: 12/14/2022]
Abstract
We investigated the effect of minocycline on neuronal damage in the hippocampus and striatum in a mouse model of transient global forebrain ischemia. Male C57BL/6 mice were anesthetized with halothane and subjected to bilateral occlusion of the common carotid artery (BCCAO) for 30 min. Minocycline (90 mg/kg, i.p., qd) or saline was injected immediately after BCCAO and daily for the next two days (45 mg/kg, i.p., bid). In order to reduce the variability in ischemic neuronal damage, we applied selection criteria based on regional cerebral blood flow (rCBF), evaluated using laser Doppler flowmetry, and the plasticity of the posterior communicating artery (PcomA), evaluated using India ink solution. In animals with rCBF that was less than 15% of the baseline value and with a smaller PcomA, of diameter less than one-third that of the basilar artery, we consistently observed neuronal damage in the striatum and hippocampal subfields, including medial CA1, CA2, and CA4. When the effect of minocycline was assessed with cresyl violet staining, neuronal damage in the medial part of the CA1 subfield and the striatum was found to be significantly attenuated, although minocycline did not protect against neuronal damage in the remaining hippocampal subfields. Immunohistochemistry for NeuN, adenosine A1 receptor, and SCIP/Oct-6 confirmed the region-specific effect of minocycline in the hippocampus. In summary, our results suggest that minocycline protects neurons against global forebrain ischemia in a subregion-specific manner.
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Affiliation(s)
- Kyung-Ok Cho
- Department of Pharmacology, Cell Death Disease Research Center, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, 137-701, Seoul, Republic of Korea
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Wang AL, Yuan M, Neufeld AH. Degeneration of neuronal cell bodies following axonal injury in Wld(S) mice. J Neurosci Res 2007; 84:1799-807. [PMID: 17022038 DOI: 10.1002/jnr.21075] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The phenotype of Wld(S) ("slow Wallerian degeneration") mice demonstrates prolonged survival of injured axons. However, whether the Wld(S) mutation delays degeneration of the neuronal cell body following axonal injury is unclear. We used a retrograde model of axonal transport failure in Wld(S) mice to test whether the mutant Wld(S) protein has any beneficial effect on the neuronal cell body. Retrograde axonal transport was physically blocked by optic nerve crush and confirmed by the absence of Fluoro-Gold labeling in wild-type and in Wld(S) mice. After this axonal injury, there was marked protection of axonal degeneration in the Wld(S) phenotype, as confirmed by immunohistochemistry and electron microscopy. However, the Wld(S) protein, localized in the nucleus of retinal ganglion cells, did not prevent or delay degeneration of the retinal ganglion cell body, confirmed by TUNEL staining and Fluoro-Gold labeling. These results imply that, after axonal injury, Wallerian degeneration of axons and degeneration of the neuronal cell body have different mechanisms, which are autonomous and independent of each other. Although the Wld(S) phenotype can be used to demonstrate stable enucleate axons, the mutation is unlikely to protect neurons in neurodegenerative diseases in which there is failure of retrograde transport.
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Affiliation(s)
- Ai Ling Wang
- Laboratory for the Investigation of the Aging Retina, Department of Ophthalmology, Northwestern University School of Medicine, Chicago, IL 60611, USA.
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Cai AL, Zipfel GJ, Sheline CT. Zinc neurotoxicity is dependent on intracellular NAD levels and the sirtuin pathway. Eur J Neurosci 2006; 24:2169-76. [PMID: 17042794 DOI: 10.1111/j.1460-9568.2006.05110.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Zinc neurotoxicity has been demonstrated in ischemic, seizure, hypoglycemic, and trauma-induced neuronal death where Zn(2+) is thought to be synaptically released and taken up in neighbouring neurons, reaching toxic concentrations. We previously demonstrated that toxicity of extracellular Zn(2+) depended on entry, elevation in intracellular free Zn(2+) ([Zn(2+)](i)), a reduction in NAD(+) and ATP levels, and dysfunction of glycolysis and cellular metabolism. We suggested that PARP-1 activation alone can not explain this loss of neuronal NAD(+). NAD(+) was recently demonstrated to permeate neurons and glia, and we have now shown that exogenous NAD(+) can reduce Zn(2+) neurotoxicity, and 3-acetylpyridine, which generates inactive NAD(+), potentiated Zn(2+) neurotoxicity. Sirtinol and 2-hydroxynaphthaldehyde, inhibitors of the sirtuin pathway (SIRT proteins are NAD(+)-catabolic protein deacetylases), attenuated both acute and chronic Zn(2+) neurotoxicity. Resveratrol and fisetin (sirtuin activators) potentiated NAD(+) loss and Zn(2+) neurotoxicities. Furthermore, neuronal cultures derived from the Wld(s) mouse, which overexpress the NAD(+) synthetic enzyme nicotinamide mononucleotide adenyl transferase (NMNAT-1), had reduced sensitivity to Zn(2+) neurotoxicity. Finally, nicotinamide was demonstrated to attenuate CA1 neuronal death after 10 min of global ischemia in rat even if administered 1 h after the insult. Together with previous data, these results further implicate NAD(+) levels in Zn(2+) neurotoxicity.
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Affiliation(s)
- Ai-Li Cai
- Department of Neurology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO, USA
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Adalbert R, Nógrádi A, Szabó A, Coleman MP. The slow Wallerian degeneration genein vivoprotects motor axons but not their cell bodies after avulsion and neonatal axotomy. Eur J Neurosci 2006; 24:2163-8. [PMID: 17074042 DOI: 10.1111/j.1460-9568.2006.05103.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The slow Wallerian degeneration gene (Wld(S)) delays Wallerian degeneration and axon pathology for several weeks in mice and rats. Interestingly, neuronal cell death is also delayed in some in vivo models, most strikingly in the progressive motoneuronopathy mouse. Here, we tested the hypothesis that Wld(S) has a direct protective effect on motoneurone cell bodies in vivo. Cell death was induced in rat L4 motoneurones by intravertebral avulsion of the corresponding ventral roots. This simultaneously removed most of the motor axon, minimizing the possibility that the protective effect toward axons could rescue cell bodies secondarily. There was no significant difference between the survival of motoneurones in control and Wld(S) rats, suggesting that the Wld(S) gene has no direct protective effect on cell bodies. We also tested for any delay in apoptotic motoneurone death following neonatal nerve injury in Wld(S) rats and found that, unlike Wld(S) mice, Wld(S) rats show no delay in cell death. However, the corresponding distal axons were preserved, confirming that motoneurone cell bodies and motor axons die by different mechanisms. Thus, Wld(S) does not directly prevent death of motoneurone cell bodies. It follows that the protection of neuronal cell bodies observed in several disease and injury models where axons or significant axonal stumps remain is most probably secondary to axonal protection.
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