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Bizanti A, Zhang Y, Toledo Z, Bendowski KT, Harden SW, Mistareehi A, Chen J, Gozal D, Heal M, Christie R, Hunter PJ, Paton JFR, Cheng ZJ. Chronic intermittent hypoxia remodels catecholaminergic nerve innervation in mouse atria. J Physiol 2024; 602:49-71. [PMID: 38156943 PMCID: PMC10842556 DOI: 10.1113/jp284961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 10/04/2023] [Indexed: 01/03/2024] Open
Abstract
Chronic intermittent hypoxia (CIH, a model for sleep apnoea) is a major risk factor for several cardiovascular diseases. Autonomic imbalance (sympathetic overactivity and parasympathetic withdrawal) has emerged as a causal contributor of CIH-induced cardiovascular disease. Previously, we showed that CIH remodels the parasympathetic pathway. However, whether CIH induces remodelling of the cardiac sympathetic innervation remains unknown. Mice (male, C57BL/6J, 2-3 months) were exposed to either room air (RA, 21% O2 ) or CIH (alternating 21% and 5.7% O2 , every 6 min, 10 h day-1 ) for 8-10 weeks. Flat-mounts of their left and right atria were immunohistochemically labelled for tyrosine hydroxylase (TH, a sympathetic marker). Using a confocal microscope (or fluorescence microscope) and Neurlocudia 360 digitization and tracing system, we scanned both the left and right atria and quantitatively analysed the sympathetic axon density in both groups. The segmentation data was mapped onto a 3D mouse heart scaffold. Our findings indicated that CIH significantly remodelled the TH immunoreactive (-IR) innervation of the atria by increasing its density at the sinoatrial node, the auricles and the major veins attached to the atria (P < 0.05, n = 7). Additionally, CIH increased the branching points of TH-IR axons and decreased the distance between varicosities. Abnormal patterns of TH-IR axons around intrinsic cardiac ganglia were also found following CIH. We postulate that the increased sympathetic innervation may further amplify the effects of enhanced CIH-induced central sympathetic drive to the heart. Our work provides an anatomical foundation for the understanding of CIH-induced autonomic imbalance. KEY POINTS: Chronic intermittent hypoxia (CIH, a model for sleep apnoea) causes sympathetic overactivity, cardiovascular remodelling and hypertension. We determined the effect of CIH on sympathetic innervation of the mouse atria. In vivo CIH for 8-10 weeks resulted in an aberrant axonal pattern around the principal neurons within intrinsic cardiac ganglia and an increase in the density, branching point, tortuosity of catecholaminergic axons and atrial wall thickness. Utilizing mapping tool available from NIH (SPARC) Program, the topographical distribution of the catecholaminergic innervation of the atria were integrated into a novel 3D heart scaffold for precise anatomical distribution and holistic quantitative comparison between normal and CIH mice. This work provides a unique neuroanatomical understanding of the pathophysiology of CIH-induced autonomic remodelling.
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Affiliation(s)
- Ariege Bizanti
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Yuanyuan Zhang
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Zulema Toledo
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Kohlton T Bendowski
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Scott W Harden
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Anas Mistareehi
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - Jin Chen
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
| | - David Gozal
- Joan C. Edwards School of medicine, Marshall University, Huntington, WV, USA
| | - Maci Heal
- MBF Bioscience, Williston, Vermont, USA
| | - Richard Christie
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Peter J Hunter
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Julian F R Paton
- Department Physiology, Manaaki Manawa-the Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Zixi Jack Cheng
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA
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Cao Y, Sun W, Liu C, Zhou Z, Deng Z, Zhang M, Yan M, Yin X, Zhu X. Resveratrol ameliorates diabetic encephalopathy through PDE4D/PKA/Drp1 signaling. Brain Res Bull 2023; 203:110763. [PMID: 37722608 DOI: 10.1016/j.brainresbull.2023.110763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/05/2023] [Accepted: 09/15/2023] [Indexed: 09/20/2023]
Abstract
Diabetic encephalopathy (DE) is a central nervous complication of diabetes mellitus which is characterized by cognitive impairment and neurochemical abnormalities. However, no effective approaches are available to prevent its progression and development. PDE4D serves many functions in the pathogenesis of neurodegenerative diseases involving PKA signaling. This study illustrated the role of PDE4D in DE and investigated whether resveratrol protected against DE via inhibiting PDE4D. db/db male mice and hippocampus cell line (HT22) were used to investigate the role of PDE4D and the protective effect of resveratrol on cognitive function under high glucose (HG). PDE4D overexpression or knockdown lentivirus and PKA specific inhibitor H89 were used to further identify the indispensable role of PDE4D/PKA signaling pathway in resveratrol's amelioration effect of neurotoxicity. Resveratrol attenuated cognitive impairment in db/db mice, reduced PDE4D protein, restored the impaired mitochondrial function in db/db mice. The in vitro study also confirmed the neuroprotective effect of resveratrol on neurotoxicity. PDE4D overexpression resulted in cell injury and downregulation of cAMP, PKA and pDrp1(Ser637) under normal condition. In contrast, PDE4D knockdown improved cell injury and elevated cAMP, PKA and pDrp1(Ser637) levels caused in HG-cultured HT22 cells. PDE4D over-expression blunted the improvement effects of resveratrol on PKA, pDrp1(Ser637) and mitochondrial function. Moreover, PKA inhibitor H89 blunted the inhibitory effects of resveratrol on pDrp1(Ser637) and mitochondrial function in HG-treated HT22. These data indicated that resveratrol may improve cognitive impairment in db/db mice by modulating mitochondrial function through the PDE4D dependent pathway.
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Affiliation(s)
- Yanjuan Cao
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Wen Sun
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Chang Liu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Zihui Zhou
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Zongli Deng
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Mingjie Zhang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Meng Yan
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Xiaoxing Yin
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China
| | - Xia Zhu
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, Xuzhou Medical University, Xuzhou, Jiangsu Province 221004, China.
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Huang YQ, Gu X, Chen X, Du YT, Chen BC, Sun FY. BMECs Ameliorate High Glucose-Induced Morphological Aberrations and Synaptic Dysfunction via VEGF-Mediated Modulation of Glucose Uptake in Cortical Neurons. Cell Mol Neurobiol 2023; 43:3575-3592. [PMID: 37418138 PMCID: PMC10477237 DOI: 10.1007/s10571-023-01366-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 05/23/2023] [Indexed: 07/08/2023]
Abstract
It has been demonstrated that diabetes cause neurite degeneration in the brain and cognitive impairment and neurovascular interactions are crucial for maintaining brain function. However, the role of vascular endothelial cells in neurite outgrowth and synaptic formation in diabetic brain is still unclear. Therefore, present study investigated effects of brain microvascular endothelial cells (BMECs) on high glucose (HG)-induced neuritic dystrophy using a coculture model of BMECs with neurons. Multiple immunofluorescence labelling and western blot analysis were used to detect neurite outgrowth and synapsis formation, and living cell imaging was used to detect uptake function of neuronal glucose transporters. We found cocultured with BMECs significantly reduced HG-induced inhibition of neurites outgrowth (including length and branch formation) and delayed presynaptic and postsynaptic development, as well as reduction of neuronal glucose uptake capacity, which was prevented by pre-treatment with SU1498, a vascular endothelial growth factor (VEGF) receptor antagonist. To analyse the possible mechanism, we collected BMECs cultured condition medium (B-CM) to treat the neurons under HG culture condition. The results showed that B-CM showed the same effects as BMEC on HG-treated neurons. Furthermore, we observed VEGF administration could ameliorate HG-induced neuronal morphology aberrations. Putting together, present results suggest that cerebral microvascular endothelial cells protect against hyperglycaemia-induced neuritic dystrophy and restorate neuronal glucose uptake capacity by activation of VEGF receptors and endothelial VEGF release. This result help us to understand important roles of neurovascular coupling in pathogenesis of diabetic brain, providing a new strategy to study therapy or prevention for diabetic dementia. Hyperglycaemia induced inhibition of neuronal glucose uptake and impaired to neuritic outgrowth and synaptogenesis. Cocultured with BMECs/B-CM and VEGF treatment protected HG-induced inhibition of glucose uptake and neuritic outgrowth and synaptogenesis, which was antagonized by blockade of VEGF receptors. Reduction of glucose uptake may further deteriorate impairment of neurites outgrowth and synaptogenesis.
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Affiliation(s)
- Yu-Qi Huang
- Department of Neurobiology and Research Institute for Aging and Medicine, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 138 Yi-Xue-Yuan Road, Shanghai, 200032, People's Republic of China
- National Clinical Research Center for Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| | - Xiao Gu
- Department of Neurobiology and Research Institute for Aging and Medicine, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 138 Yi-Xue-Yuan Road, Shanghai, 200032, People's Republic of China
- National Clinical Research Center for Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| | - Xiao Chen
- Department of Neurobiology and Research Institute for Aging and Medicine, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 138 Yi-Xue-Yuan Road, Shanghai, 200032, People's Republic of China
- National Clinical Research Center for Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| | - Yi-Ting Du
- Department of Neurobiology and Research Institute for Aging and Medicine, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 138 Yi-Xue-Yuan Road, Shanghai, 200032, People's Republic of China
- National Clinical Research Center for Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| | - Bin-Chi Chen
- Department of Neurobiology and Research Institute for Aging and Medicine, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 138 Yi-Xue-Yuan Road, Shanghai, 200032, People's Republic of China
- National Clinical Research Center for Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China
| | - Feng-Yan Sun
- Department of Neurobiology and Research Institute for Aging and Medicine, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, 138 Yi-Xue-Yuan Road, Shanghai, 200032, People's Republic of China.
- National Clinical Research Center for Aging and Medicine, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China.
- Shanghai Key Laboratory of Bioactive Small Molecules, School of Basic Medical Sciences, Institute of Biomedical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, People's Republic of China.
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Wu HF, Huang CW, Art J, Liu HX, Hart GW, Zeltner N. O-GlcNAcylation is crucial for sympathetic neuron development, maintenance, functionality and contributes to peripheral neuropathy. Front Neurosci 2023; 17:1137847. [PMID: 37229433 PMCID: PMC10203903 DOI: 10.3389/fnins.2023.1137847] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 04/12/2023] [Indexed: 05/27/2023] Open
Abstract
O-GlcNAcylation is a post-translational modification (PTM) that regulates a wide range of cellular functions and has been associated with multiple metabolic diseases in various organs. The sympathetic nervous system (SNS) is the efferent portion of the autonomic nervous system that regulates metabolism of almost all organs in the body. How much the development and functionality of the SNS are influenced by O-GlcNAcylation, as well as how such regulation could contribute to sympathetic neuron (symN)-related neuropathy in diseased states, remains unknown. Here, we assessed the level of protein O-GlcNAcylation at various stages of symN development, using a human pluripotent stem cell (hPSC)-based symN differentiation paradigm. We found that pharmacological disruption of O-GlcNAcylation impaired both the growth and survival of hPSC-derived symNs. In the high glucose condition that mimics hyperglycemia, hPSC-derived symNs were hyperactive, and their regenerative capacity was impaired, which resembled typical neuronal defects in patients and animal models of diabetes mellitus. Using this model of sympathetic neuropathy, we discovered that O-GlcNAcylation increased in symNs under high glucose, which lead to hyperactivity. Pharmacological inhibition of O-GlcNAcylation rescued high glucose-induced symN hyperactivity and cell stress. This framework provides the first insight into the roles of O-GlcNAcylation in both healthy and diseased human symNs and may be used as a platform for therapeutic studies.
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Affiliation(s)
- Hsueh-Fu Wu
- Center for Molecular Medicine, University of Georgia, Athens, GA, United States
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Chia-Wei Huang
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Jennifer Art
- Center for Molecular Medicine, University of Georgia, Athens, GA, United States
- Biomedical and Translational Sciences Institute, Neuroscience Program, University of Georgia, Athens, GA, United States
| | - Hong-Xiang Liu
- Regenerative Bioscience Center, Department of Animal and Dairy Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, GA, United States
| | - Gerald W. Hart
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States
| | - Nadja Zeltner
- Center for Molecular Medicine, University of Georgia, Athens, GA, United States
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
- Department of Cellular Biology, University of Georgia, Athens, GA, United States
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5
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Maselli RA, Wei DT, Hodgson TS, Sampson JB, Vazquez J, Smith HL, Pytel P, Ferns M. Dominant and recessive congenital myasthenic syndromes caused by SYT2 mutations. Muscle Nerve 2021; 64:219-224. [PMID: 34037996 DOI: 10.1002/mus.27332] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/14/2021] [Accepted: 05/19/2021] [Indexed: 01/11/2023]
Abstract
INTRODUCTION/AIMS We studied a patient with a congenital myasthenic syndrome (CMS) caused by a dominant mutation in the synaptotagmin 2 gene (SYT2) and compared the clinical features of this patient with those of a previously described patient with a recessive mutation in the same gene. METHODS We performed electrodiagnostic (EDX) studies, genetic studies, muscle biopsy, microelectrode recordings and electron microscopy (EM). RESULTS Both patients presented with muscle weakness and bulbar deficits, which were worse in the recessive form. EDX studies showed presynaptic failure, which was more prominent in the recessive form. Microelectrode studies in the dominant form showed a marked reduction of the quantal content, which increased linearly with higher frequencies of nerve stimulation. The MEPP frequencies were normal at rest but increased markedly with higher frequencies of nerve stimulation. The EM demonstrated overdeveloped postsynaptic folding, and abundant endosomes, multivesicular bodies and degenerative lamellar bodies inside small nerve terminals. DISCUSSION The recessive form of CMS caused by a SYT2 mutation showed far more severe clinical manifestations than the dominant form. The pathogenesis of the dominant form likely involves a dominant-negative effect due to disruption of the dual function of synaptotagmin as a Ca2+ -sensor and modulator of synaptic vesicle exocytosis.
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Affiliation(s)
- Ricardo A Maselli
- Department of Neurology, University of California Davis, Sacramento, California, USA
| | - David T Wei
- Department of Neurology, University of California Davis, Sacramento, California, USA
| | - Trent S Hodgson
- Kaiser Permanente Oakland Medical Center, Oakland, California, USA
| | - Jacinda B Sampson
- Department of Neurology, Stanford University, Palo Alto, California, USA
| | - Jessica Vazquez
- Department of Neurology, University of California Davis, Sacramento, California, USA
| | - Heather L Smith
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Peter Pytel
- Department of Pathology, The University of Chicago, Chicago, Illinois, USA
| | - Michael Ferns
- Department of Anesthesiology, University of California Davis, Davis, California, USA
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Silva TM, Borniger JC, Alves MJ, Alzate Correa D, Zhao J, Fadda P, Toland AE, Takakura AC, Moreira TS, Czeisler CM, Otero JJ. Machine learning approaches reveal subtle differences in breathing and sleep fragmentation in Phox2b-derived astrocytes ablated mice. J Neurophysiol 2021; 125:1164-1179. [PMID: 33502943 DOI: 10.1152/jn.00155.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Modern neurophysiology research requires the interrogation of high-dimensionality data sets. Machine learning and artificial intelligence (ML/AI) workflows have permeated into nearly all aspects of daily life in the developed world but have not been implemented routinely in neurophysiological analyses. The power of these workflows includes the speed at which they can be deployed, their availability of open-source programming languages, and the objectivity permitted in their data analysis. We used classification-based algorithms, including random forest, gradient boosted machines, support vector machines, and neural networks, to test the hypothesis that the animal genotypes could be separated into their genotype based on interpretation of neurophysiological recordings. We then interrogate the models to identify what were the major features utilized by the algorithms to designate genotype classification. By using raw EEG and respiratory plethysmography data, we were able to predict which recordings came from genotype class with accuracies that were significantly improved relative to the no information rate, although EEG analyses showed more overlap between groups than respiratory plethysmography. In comparison, conventional methods where single features between animal classes were analyzed, differences between the genotypes tested using baseline neurophysiology measurements showed no statistical difference. However, ML/AI workflows successfully were capable of providing successful classification, indicating that interactions between features were different in these genotypes. ML/AI workflows provide new methodologies to interrogate neurophysiology data. However, their implementation must be done with care so as to provide high rigor and reproducibility between laboratories. We provide a series of recommendations on how to report the utilization of ML/AI workflows for the neurophysiology community.NEW & NOTEWORTHY ML/AI classification workflows are capable of providing insight into differences between genotypes for neurophysiology research. Analytical techniques utilized in the neurophysiology community can be augmented by implementing ML/AI workflows. Random forest is a robust classification algorithm for respiratory plethysmography data. Utilization of ML/AI workflows in neurophysiology research requires heightened transparency and improved community research standards.
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Affiliation(s)
- Talita M Silva
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine.,Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo
| | | | - Michele Joana Alves
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine
| | - Diego Alzate Correa
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine
| | - Jing Zhao
- Department of Biomedical Informatics, The Ohio State University College of Dentistry
| | - Paolo Fadda
- Genomics Shared Resource-Comprehensive Cancer Center, The Ohio State University
| | - Amanda Ewart Toland
- Genomics Shared Resource-Comprehensive Cancer Center, The Ohio State University.,Department of Cancer Biology and Genetics, The Ohio State University College of Medicine
| | - Ana C Takakura
- Department of Pharmacology, Institute of Biomedical Science, University of São Paulo
| | - Thiago S Moreira
- Department of Physiology and Biophysics, Institute of Biomedical Science, University of São Paulo
| | - Catherine M Czeisler
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine
| | - José Javier Otero
- Division of Neuropathology, Department of Pathology, The Ohio State University College of Medicine
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7
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Parlanti P, Pal-Ghosh S, Williams A, Tadvalkar G, Popratiloff A, Stepp MA. Axonal debris accumulates in corneal epithelial cells after intraepithelial corneal nerves are damaged: A focused Ion Beam Scanning Electron Microscopy (FIB-SEM) study. Exp Eye Res 2020; 194:107998. [PMID: 32209319 PMCID: PMC7697722 DOI: 10.1016/j.exer.2020.107998] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/13/2020] [Accepted: 03/07/2020] [Indexed: 12/15/2022]
Abstract
The intraepithelial corneal nerves (ICNs) that innervate the corneal epithelium are maintained through interactions with corneal epithelial cells and the extracellular matrix they produce. One to several axons bundle together within the basal cell layer and extend parallel to the ocular surface or branch and extend apically. Here we use 3-dimentional (3D) ultrastructural reconstructions of control and trephine injured mouse corneal epithelium and stroma produced using Focused Ion Beam Scanning Electron Microscope (FIB-SEM) to determine whether corneal epithelial or immune cells resident in the epithelium remove axonal debris and degrade it in their lysosomes after trephine injury to the cornea. We demonstrate that axonal fragments are internalized in the corneal epithelium and accumulate within electron dense structures consistent with lysosomes 3 h after trephine injury in both epithelial and immune cells located among the basal cells of the trephine injured cornea. Confocal imaging showed fewer CD45+ immune cells within the corneal epithelium after trephine injury compared to controls. The resolution obtained using FIB-SEM also allowed us to show that the presence of sensory axons at the basal aspect of the epithelial basal cells close to the anterior aspect of the epithelial basement membrane (EBM) is associated with a focal reduction in EBM thickness. In addition, we show using FIB-SEM and confocal imaging that superficial trephine injuries that do not penetrate the stroma, damage the integrity of anterior stromal nerves. These studies are the first to look at the mouse cornea following nerve injury using FIB-SEM.
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Affiliation(s)
- Paola Parlanti
- GW Nanofabrication and Imaging Center, The George Washington School of Medicine and Health Sciences, Washington DC, 20052, USA
| | - Sonali Pal-Ghosh
- Department of Anatomy and Cell Biology, The George Washington School of Medicine and Health Sciences, Washington DC, 20052, USA
| | - Alexa Williams
- Department of Anatomy and Cell Biology, The George Washington School of Medicine and Health Sciences, Washington DC, 20052, USA
| | - Gauri Tadvalkar
- Department of Anatomy and Cell Biology, The George Washington School of Medicine and Health Sciences, Washington DC, 20052, USA
| | - Anastas Popratiloff
- GW Nanofabrication and Imaging Center, The George Washington School of Medicine and Health Sciences, Washington DC, 20052, USA; Department of Anatomy and Cell Biology, The George Washington School of Medicine and Health Sciences, Washington DC, 20052, USA
| | - Mary Ann Stepp
- Department of Anatomy and Cell Biology, The George Washington School of Medicine and Health Sciences, Washington DC, 20052, USA; Department of Ophthalmology, The George Washington School of Medicine and Health Sciences, Washington DC, 20052, USA.
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8
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Lu M, Yi T, Xiong Y, Wang Q, Yin N. Cortex Mori Radicis extract promotes neurite outgrowth in diabetic rats by activating PI3K/AKT signaling and inhibiting Ca2+ influx associated with the upregulation of transient receptor potential canonical channel 1. Mol Med Rep 2019; 21:320-328. [PMID: 31939614 PMCID: PMC6896399 DOI: 10.3892/mmr.2019.10839] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 10/16/2019] [Indexed: 01/16/2023] Open
Abstract
Cortex Mori Radicis extract (CMR) has various pharmacological properties, such as anti‑inflammatory, anti‑allergic and anti‑hyperglycemic effects. However, the effects and mechanisms of CMR in the neuroregeneration of diabetic peripheral neuropathy (DPN) are unclear. In the present study, the effects of CMR on neurite outgrowth of dorsal root ganglia (DRG) neurons in diabetic rats were investigated and its underlying mechanisms were explored. SD rats were subjected to a high‑fat diet with low‑dose streptozotocin to induce a Type II diabetes model with peripheral neuropathy. CMR was then applied for four weeks continuously with or without injection of small interfere (si)RNA targeting the transient receptor potential canonical channel 1 (TRPC1) via the tail vein. Blood glucose levels, the number of Nissl bodies, neurite outgrowth and growth cone turning in DRG neurons were evaluated. The expression of TRPC1 protein, Ca2+ influx and activation of the PI3K/AKT signaling pathway were also investigated. The results of the present study showed that CMR significantly lowered blood glucose levels, reversed the loss of Nissl bodies, induced neurite outgrowth and restored the response of the growth cone of DRG neurons in diabetic rats. CMR exerted neurite outgrowth‑promoting effects by increasing TRPC1 expression, reducing Ca2+ influx and enhancing AKT phosphorylation. siRNA targeting TRPC1 in the CMR group abrogated its anti‑diabetic and neuroregenerative effects, suggesting the involvement of TRPC1 in the biological effects of CMR on DPN.
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Affiliation(s)
- Min Lu
- Department of Histology and Embryology, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, P.R. China
| | - Tao Yi
- College of Acupuncture and Moxibustion, Hubei University of Chinese Medicine, Wuhan, Hubei 430065, P.R. China
| | - Yong Xiong
- College of Acupuncture and Moxibustion, Hubei University of Chinese Medicine, Wuhan, Hubei 430065, P.R. China
| | - Qian Wang
- Department of Pathogen Biology, School of Basic Medical Sciences, Hubei University of Chinese Medicine, Wuhan, Hubei 430065, P.R. China
| | - Nina Yin
- Department of Anatomy, School of Basic Medical Sciences, Hubei University of Chinese Medicine, Wuhan, Hubei 430065, P.R. China
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Schmidt RE. Mitochondriopathy: The unifying concept in distal neuropathies? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2019; 145:1-12. [PMID: 31208521 DOI: 10.1016/bs.irn.2019.05.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This is a new, exciting time for the study of peripheral nerve and its diseases. For many years research in peripheral neuropathies largely involved descriptive analysis, a situation which is now rapidly giving way to hypothesis testing with the development and validation of molecular genetic tools. Although it has been known for some time that many neuropathies target the most distal portions of the longest peripheral nerves, a process variously referred to as central-peripheral distal neuropathy, "dying-back" neuropathy, or "stocking-glove" neuropathy, proposed mechanisms driving axon loss have been generally unproven/untestable. Studies have shown that mitochondrial DNA mutations accumulate in distal axons and a unifying theory of distal neuropathy has been proposed based on underlying mitochondrial aging defects in mitogenesis and, thus, distal axon susceptibility, particularly if axonal transport defects also accompanied them. Increased levels of mtDNA mutations have been described in some painful neuropathies (e.g., HIV) compared to baseline HIV patients and controls. For some time no therapies were available to preserve and prevent the development of peripheral neuropathy and, with a variety of expected pathogenetic mechanisms, complex cocktails of therapeutic agents were envisioned. Although structure and ultrastructure continue to be relevant in the studies of mitochondriopathy-driven neuropathies, more techniques have been added and more complex hypotheses now expand the concept and focus directly on mitochondrial pathology or dysfunction. It is now possible to definitively test possible pathogenetic mechanisms with a variety of new tools and to formulate new and testable hypotheses.
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Affiliation(s)
- Robert E Schmidt
- Washington University School of Medicine, Saint Louis, Missouri.
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10
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Czeisler CM, Silva TM, Fair SR, Liu J, Tupal S, Kaya B, Cowgill A, Mahajan S, Silva PE, Wang Y, Blissett AR, Göksel M, Borniger JC, Zhang N, Fernandes‐Junior SA, Catacutan F, Alves MJ, Nelson RJ, Sundaresean V, Rekling J, Takakura AC, Moreira TS, Otero JJ. The role of PHOX2B-derived astrocytes in chemosensory control of breathing and sleep homeostasis. J Physiol 2019; 597:2225-2251. [PMID: 30707772 PMCID: PMC6462490 DOI: 10.1113/jp277082] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/28/2019] [Indexed: 01/07/2023] Open
Abstract
KEY POINTS The embryonic PHOX2B-progenitor domain generates neuronal and glial cells which together are involved in chemosensory control of breathing and sleep homeostasis. Ablating PHOX2B-derived astrocytes significantly contributes to secondary hypoxic respiratory depression as well as abnormalities in sleep homeostasis. PHOX2B-derived astrocyte ablation results in axonal pathologies in the retrotrapezoid nucleus. ABSTRACT We identify in mice a population of ∼800 retrotrapezoid nucleus (RTN) astrocytes derived from PHOX2B-positive, OLIG3-negative progenitor cells, that interact with PHOX2B-expressing RTN chemosensory neurons. PHOX2B-derived astrocyte ablation during early life results in adult-onset O2 chemoreflex deficiency. These animals also display changes in sleep homeostasis, including fragmented sleep and disturbances in delta power after sleep deprivation, all without observable changes in anxiety or social behaviours. Ultrastructural evaluation of the RTN demonstrates that PHOX2B-derived astrocyte ablation results in features characteristic of degenerative neuro-axonal dystrophy, including abnormally dilated axon terminals and increased amounts of synapses containing autophagic vacuoles/phagosomes. We conclude that PHOX2B-derived astrocytes are necessary for maintaining a functional O2 chemosensory reflex in the adult, modulate sleep homeostasis, and are key regulators of synaptic integrity in the RTN region, which is necessary for the chemosensory control of breathing. These data also highlight how defects in embryonic development may manifest as neurodegenerative pathology in an adult.
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Affiliation(s)
| | - Talita M. Silva
- Department of Physiology and BiophysicsInstitute of Biomedical ScienceUniversity of Sao PauloSao PauloBrazil
| | - Summer R. Fair
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | - Jillian Liu
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | - Srinivasan Tupal
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | - Behiye Kaya
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | - Aaron Cowgill
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | - Salil Mahajan
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | - Phelipe E. Silva
- Department of Physiology and BiophysicsInstitute of Biomedical ScienceUniversity of Sao PauloSao PauloBrazil
| | - Yangyang Wang
- Department of NeuroscienceThe Ohio State University College of MedicineColumbusOHUSA
- The Ohio State University Mathematical Biosciences InstituteColumbusOHUSA
| | - Angela R. Blissett
- Department of Mechanical and Aerospace EngineeringThe Ohio State University College of EngineeringColumbusOHUSA
| | - Mustafa Göksel
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | - Jeremy C. Borniger
- Department of NeuroscienceThe Ohio State University College of MedicineColumbusOHUSA
| | - Ning Zhang
- Department of NeuroscienceWest Virginia UniversityWVUSA
| | - Silvio A. Fernandes‐Junior
- The Ohio State University Campus Microscopy and Imaging FacilityColumbusOHUSA
- Department of PharmacologyInstitute of Biomedical ScienceUniversity of São PauloSao PauloBrazil
| | - Fay Catacutan
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | - Michele J. Alves
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | | | - Vishnu Sundaresean
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
| | - Jens Rekling
- Department of NeuroscienceUniversity of CopenhagenCopenhagenDenmark
| | - Ana C. Takakura
- Department of PharmacologyInstitute of Biomedical ScienceUniversity of São PauloSao PauloBrazil
| | - Thiago S. Moreira
- Department of Physiology and BiophysicsInstitute of Biomedical ScienceUniversity of Sao PauloSao PauloBrazil
| | - José J. Otero
- Department of PathologyThe Ohio State University College of MedicineColumbusOHUSA
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Effects of Mitochondrial Dysfunction via AMPK/PGC-1 α Signal Pathway on Pathogenic Mechanism of Diabetic Peripheral Neuropathy and the Protective Effects of Chinese Medicine. Chin J Integr Med 2019; 25:386-394. [DOI: 10.1007/s11655-018-2579-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 05/14/2018] [Indexed: 01/12/2023]
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12
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Cheng Z(J. Vagal cardiac efferent innervation in F344 rats: Effects of chronic intermittent hypoxia. Auton Neurosci 2017; 203:9-16. [DOI: 10.1016/j.autneu.2016.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 10/05/2016] [Accepted: 10/27/2016] [Indexed: 12/27/2022]
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13
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Akhter F, Chen D, Yan SF, Yan SS. Mitochondrial Perturbation in Alzheimer's Disease and Diabetes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2017; 146:341-361. [PMID: 28253990 DOI: 10.1016/bs.pmbts.2016.12.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Mitochondria are well-known cellular organelles that play a vital role in cellular bioenergetics, heme biosynthesis, thermogenesis, calcium homeostasis, lipid catabolism, and other metabolic activities. Given the extensive role of mitochondria in cell function, mitochondrial dysfunction plays a part in many diseases, including diabetes and Alzheimer's disease (AD). In most cases, there is overwhelming evidence that impaired mitochondrial function is a causative factor in these diseases. Studying mitochondrial function in diseased cells vs healthy cells may reveal the modified mechanisms and molecular components involved in specific disease states. In this chapter, we provide a concise overview of the major recent findings on mitochondrial abnormalities and their link to synaptic dysfunction relevant to neurodegeneration and cognitive decline in AD and diabetes. Our increased understanding of the role of mitochondrial perturbation indicates that the development of specific small molecules targeting aberrant mitochondrial function could provide therapeutic benefits for the brain in combating aging-related dementia and neurodegenerative diseases by powering up brain energy and improving synaptic function and transmission.
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Affiliation(s)
- F Akhter
- School of Pharmacy, Higuchi Bioscience Center, University of Kansas, Lawrence, KS, United States
| | - D Chen
- School of Pharmacy, Higuchi Bioscience Center, University of Kansas, Lawrence, KS, United States
| | - S F Yan
- School of Pharmacy, Higuchi Bioscience Center, University of Kansas, Lawrence, KS, United States
| | - S S Yan
- School of Pharmacy, Higuchi Bioscience Center, University of Kansas, Lawrence, KS, United States.
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14
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Yan S, Du F, Wu L, Zhang Z, Zhong C, Yu Q, Wang Y, Lue LF, Walker DG, Douglas JT, Yan SS. F1F0 ATP Synthase-Cyclophilin D Interaction Contributes to Diabetes-Induced Synaptic Dysfunction and Cognitive Decline. Diabetes 2016; 65:3482-3494. [PMID: 27554467 PMCID: PMC5079631 DOI: 10.2337/db16-0556] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 08/09/2016] [Indexed: 02/03/2023]
Abstract
Mitochondrial abnormalities are well known to cause cognitive decline. However, the underlying molecular basis of mitochondria-associated neuronal and synaptic dysfunction in the diabetic brain remains unclear. Here, using a mitochondrial single-channel patch clamp and cyclophilin D (CypD)-deficient mice (Ppif -/-) with streptozotocin-induced diabetes, we observed an increase in the probability of Ca2+-induced mitochondrial permeability transition pore (mPTP) opening in brain mitochondria of diabetic mice, which was further confirmed by mitochondrial swelling and cytochrome c release induced by Ca2+ overload. Diabetes-induced elevation of CypD triggers enhancement of F1F0 ATP synthase-CypD interaction, which in turn leads to mPTP opening. Indeed, in patients with diabetes, brain cypD protein levels were increased. Notably, blockade of the F1F0 ATP synthase-CypD interaction by CypD ablation protected against diabetes-induced mPTP opening, ATP synthesis deficits, oxidative stress, and mitochondria dysfunction. Furthermore, the absence of CypD alleviated deficits in synaptic plasticity, learning, and memory in diabetic mice. Thus, blockade of ATP synthase interaction with CypD provides a promising new target for therapeutic intervention in diabetic encephalopathy.
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Affiliation(s)
- Shijun Yan
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Fang Du
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Long Wu
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Zhihua Zhang
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Changjia Zhong
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Qing Yu
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Yongfu Wang
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Lih-Fen Lue
- Neurodegenerative Disease Research Center, Biodesign Institute, Arizona State University, Tempe, AZ
| | - Douglas G Walker
- Neurodegenerative Disease Research Center, Biodesign Institute, Arizona State University, Tempe, AZ
| | - Justin T Douglas
- Nuclear Magnetic Resonance Laboratory, Molecular Structures Group, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Shirley ShiDu Yan
- Department of Pharmacology & Toxicology and Higuchi Bioscience Center, School of Pharmacy, University of Kansas, Lawrence, KS
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15
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Rusu MC, Mănoiu VS, Vrapciu AD, Hostiuc S, Mirancea N. Altered Mitochondrial Anatomy of Trigeminal Ganglia Neurons in Diabetes. Anat Rec (Hoboken) 2016; 299:1561-1570. [PMID: 27615558 DOI: 10.1002/ar.23475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Revised: 05/27/2016] [Accepted: 07/02/2016] [Indexed: 11/11/2022]
Abstract
Neurons from sensory ganglia are exposed to oxidative attack in diabetes. Altered mitochondrial morphologies are due to impaired dynamics (fusion, fission) and to cristae remodeling. This study aimed to evaluate using transmission electron microscopy mitochondrial changes in diabetic trigeminal ganglia suggestive for ignition of apoptosis, in absence of "classical" morphological signs of apoptosis. We used samples of trigeminal ganglia (from six type 2 diabetes human donors and five streptozotocin (STZ)-induced diabetic rats). In human diabetic samples we found three main distributions of mitochondria: (a) small "dark" normal mitochondria, seemingly resulted from fission processes; (b) small "dark" damaged mitochondria, with side-vesiculations (single- and double-coated), large matrix vesicles and cytosolic leakage of reactive species, mixed with larger "light" mitochondria, swollen, and with crystolysis; (c) prevailing "light" mitochondria. In STZ-treated rats a type (c) distribution prevailed, except for nociceptive neurons where we found a different distribution: large and giant mitochondria, suggestive for impaired mitochondrial fission, mitochondrial fenestrations, matrix vesicles interconnected by lamellar cristae, and mitochondrial leakage into the cytosol. Thus, the ultrastructural pattern of mitochondria damage in diabetic samples of sensory neurons may provide clues on the initiation of intrinsic apoptosis, even if the classical morphological signs of apoptosis are not present. Further studies, combining use of biochemical and ultrastructural techniques, may allow a better quantification of the degree in which mitochondrial damage, with membrane alterations and cytosolic leaks, may be used as morphological signs suggesting the point-of-no return for apoptosis. Anat Rec, 299:1561-1570, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- M C Rusu
- Division of Anatomy, Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania.
| | - V S Mănoiu
- Department of Cellular and Molecular Biology, National Institute of Research and Development for Biological Sciences, Bucharest, Romania
| | - A D Vrapciu
- Division of Anatomy, Faculty of Dental Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania
| | - S Hostiuc
- Division of Legal Medicine, Faculty of Medicine, "Carol Davila" University of Medicine and Pharmacy, Bucharest, Romania; "Mina Minovici" National Institute of Legal Medicine, Bucharest, Romania
| | - N Mirancea
- Institute of Biology of Bucharest, Romanian Academy, Bucharest, Romania
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16
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Requirement for Microglia for the Maintenance of Synaptic Function and Integrity in the Mature Retina. J Neurosci 2016; 36:2827-42. [PMID: 26937019 DOI: 10.1523/jneurosci.3575-15.2016] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED Microglia, the principal resident immune cell of the CNS, exert significant influence on neurons during development and in pathological situations. However, if and how microglia contribute to normal neuronal function in the mature uninjured CNS is not well understood. We used the model of the adult mouse retina, a part of the CNS amenable to structural and functional analysis, to investigate the constitutive role of microglia by depleting microglia from the retina in a sustained manner using genetic methods. We discovered that microglia are not acutely required for the maintenance of adult retinal architecture, the survival of retinal neurons, or the laminar organization of their dendritic and axonal compartments. However, sustained microglial depletion results in the degeneration of photoreceptor synapses in the outer plexiform layer, leading to a progressive functional deterioration in retinal light responses. Our results demonstrate that microglia are constitutively required for the maintenance of synaptic structure in the adult retina and for synaptic transmission underlying normal visual function. Our findings on constitutive microglial function are relevant in understanding microglial contributions to pathology and in the consideration of therapeutic interventions that reduce or perturb constitutive microglial function. SIGNIFICANCE STATEMENT Microglia, the principal resident immune cell population in the CNS, has been implicated in diseases in the brain and retina. However, how they contribute to the everyday function of the CNS is unclear. Using the model of the adult mouse retina, we examined the constitutive role of microglia by depleting microglia from the retina. We found that in the absence of microglia, retinal neurons did not undergo overt cell death or become structurally disorganized in their processes. However, connections between neurons called synapses begin to break down, leading to a decreased ability of the retina to transmit light responses. Our results indicate that retinal microglia contribute constitutively to the maintenance of synapses underlying healthy vision.
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17
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Shen C, Sun FL, Zhang RY, Zhang L, Li YL, Zhang L, Li L. Tetrahydroxystilbene glucoside ameliorates memory and movement functions, protects synapses and inhibits α-synuclein aggregation in hippocampus and striatum in aged mice. Restor Neurol Neurosci 2016; 33:531-41. [PMID: 26409411 DOI: 10.3233/rnn-150514] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE To investigate the effects of 2,3,5,4'-tetrahydroxystilbene-2-O-β-D-glucoside (TSG) on the memory and movement functions and its mechanisms related to synapses and α-synuclein in aged mice. METHODS The memory ability of mice was detected by step-through passive avoidance task. The movement function was measured by the pole test and rotarod test. Transmission electron microscopy was used to observe the synaptic ultrastructure. Western blotting was applied to measure the expression of synapse-related proteins and α-synuclein. RESULTS Intragastrical administration of TSG for 3 months significantly improved the memory and movement functions in aged mice. TSG treatment obviously protected the synaptic ultrastructure and increased the number of synaptic connections in the hippocampal CA1 region and striatum; enhanced the expression of synaptophysin, phosphorylated synapsin I and postsynaptic density protein 95 (PSD95), elevated phosphorylated calcium/calmodulin-dependent protein kinase II (p-CaMKII) expression, and inhibited the overexpression and aggregation of α-synuclein in the hippocampus, striatum and cerebral cortex of aged mice. CONCLUSION TSG improved the memory and movement functions in aged mice through protecting synapses and inhibiting α-synuclein overexpression and aggregation in multiple brain regions. The results suggest that TSG may be beneficial to the treatment of ageing-related neurodegenerative diseases.
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18
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Ishibashi F, Kojima R, Taniguchi M, Kosaka A, Uetake H, Tavakoli M. The Expanded Bead Size of Corneal C-Nerve Fibers Visualized by Corneal Confocal Microscopy Is Associated with Slow Conduction Velocity of the Peripheral Nerves in Patients with Type 2 Diabetes Mellitus. J Diabetes Res 2016; 2016:3653459. [PMID: 27563679 PMCID: PMC4987467 DOI: 10.1155/2016/3653459] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 06/09/2016] [Accepted: 06/19/2016] [Indexed: 12/28/2022] Open
Abstract
This study aims to establish the corneal nerve fiber (CNF) morphological alterations in a large cohort of type 2 diabetic patients and to investigate the association between the bead size, a novel parameter representing composite of accumulated mitochondria, glycogen particles, and vesicles in CNF, and the neurophysiological dysfunctions of the peripheral nerves. 162 type 2 diabetic patients and 45 healthy control subjects were studied in detail with a battery of clinical and neurological examinations and corneal confocal microscopy. Compared with controls, patients had abnormal CNF parameters. In particular the patients had reduced density and length of CNF and beading frequency and increased bead size. Alterations in CNF parameters were significant even in patients without neuropathy. The HbA1c levels were tightly associated with the bead size, which was inversely related to the motor and sensory nerve conduction velocity (NCV) and to the distal latency period of the median nerve positively. The CNF density and length positively correlated with the NCV and amplitude. The hyperglycemia-induced expansion of beads in CNF might be a predictor of slow NCV in peripheral nerves in type 2 diabetic patients.
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Affiliation(s)
- Fukashi Ishibashi
- Ishibashi Clinic, 1-9-41-2 Kushido, Hatsukaichi, Hiroshima 738-0033, Japan
- *Fukashi Ishibashi: and
| | - Rie Kojima
- Ishibashi Clinic, 1-9-41-2 Kushido, Hatsukaichi, Hiroshima 738-0033, Japan
| | - Miki Taniguchi
- Ishibashi Clinic, 1-9-41-2 Kushido, Hatsukaichi, Hiroshima 738-0033, Japan
| | - Aiko Kosaka
- Ishibashi Clinic, 1-9-41-2 Kushido, Hatsukaichi, Hiroshima 738-0033, Japan
| | - Harumi Uetake
- Ishibashi Clinic, 1-9-41-2 Kushido, Hatsukaichi, Hiroshima 738-0033, Japan
| | - Mitra Tavakoli
- Centre for Endocrinology and Diabetes, Institute of Human Development, University of Manchester, 46 Grafton Street, Manchester M13 9NT, UK
- University of Exeter Medical School, St Luke's Campus, South Cloisters, Exeter EX1 2LU, UK
- *Mitra Tavakoli:
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19
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Abstract
Diabetic neuropathy is a dying back neurodegenerative disease of the peripheral nervous system where mitochondrial dysfunction has been implicated as an etiological factor. Diabetes (type 1 or type 2) invokes an elevation of intracellular glucose concentration simultaneously with impaired growth factor support by insulin, and this dual alteration triggers a maladaptation in metabolism of adult sensory neurons. The energy sensing pathway comprising the AMP-activated protein kinase (AMPK)/sirtuin (SIRT)/peroxisome proliferator-activated receptor-γ coactivator α (PGC-1α) signaling axis is the target of these damaging changes in nutrient levels, e.g., induction of nutrient stress, and loss of insulin-dependent growth factor support and instigates an aberrant metabolic phenotype characterized by a suppression of mitochondrial oxidative phosphorylation and shift to anaerobic glycolysis. There is discussion of how this loss of mitochondrial function and transition to overreliance on glycolysis contributes to the diminishment of collateral sprouting and axon regeneration in diabetic neuropathy in the context of the highly energy-consuming nerve growth cone.
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Affiliation(s)
- Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, R4046-351 Taché Ave, Winnipeg, Manitoba, R2H 2A6, Canada.
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, R3E 0T6, Canada.
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20
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Habash T, Saleh A, Roy Chowdhury SK, Smith DR, Fernyhough P. The proinflammatory cytokine, interleukin-17A, augments mitochondrial function and neurite outgrowth of cultured adult sensory neurons derived from normal and diabetic rats. Exp Neurol 2015; 273:177-89. [PMID: 26321687 DOI: 10.1016/j.expneurol.2015.08.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 07/31/2015] [Accepted: 08/24/2015] [Indexed: 12/11/2022]
Abstract
BACKGROUND Diabetic neuropathy comprises dying back of nerve endings that reflects impairment in axonal plasticity and regenerative nerve growth. Metabolic changes in diabetes can lead to a dysregulation of hormonal mediators, such as cytokines, that may constrain distal nerve fiber growth. Interleukin-17 (IL-17A), a proinflammatory and neurotropic cytokine produced by T-cells, was significantly reduced in sciatic nerve of streptozotocin (STZ)-diabetic rats. Thus we studied the effect of IL-17A on the phenotype of sensory neurons derived from age matched control or type 1 diabetic rats. The aims were to determine the ability of IL-17A to enhance neurite outgrowth in cultured sensory neurons, investigate the signaling pathways activated by IL-17A, study the role of mitochondria and mechanistically link to neurite outgrowth. RESULTS IL-17A (10 ng/ml; p<0.05) significantly and dose-dependently increased total neurite outgrowth in cultures of adult dorsal root ganglia (DRG) sensory neurons derived from both control and streptozotocin (STZ)-diabetic rats. This enhancement was mediated by IL-17A-dependent activation of extracellular-regulated protein kinase (ERK) and phosphoinositide-3 kinase (PI-3K) signal transduction pathways. Pharmacological blockade of one of these activated pathways triggered complete inhibition of neurite outgrowth. IL-17A augmented mitochondrial bioenergetic function of sensory neurons derived from control or diabetic rats and this was also mediated via ERK or PI-3K. IL-17A-dependent elevation of bioenergetic function was associated with augmented expression of proteins of the mitochondrial electron transport system complexes. CONCLUSIONS IL-17A enhanced axonal plasticity through activation of ERK and PI-3K pathways and was associated with augmented mitochondrial bioenergetic function in sensory neurons.
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Affiliation(s)
- Tarek Habash
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada; Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB R3E 0T6, Canada
| | - Ali Saleh
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Subir K Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Darrell R Smith
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB R2H 2A6, Canada; Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB R3E 0T6, Canada.
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21
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Wagner N, Laugks U, Heckmann M, Asan E, Neuser K. Aging Drosophila melanogaster display altered pre- and postsynaptic ultrastructure at adult neuromuscular junctions. J Comp Neurol 2015; 523:2457-75. [PMID: 25940748 DOI: 10.1002/cne.23798] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Revised: 04/21/2015] [Accepted: 04/23/2015] [Indexed: 01/19/2023]
Abstract
Although age-related changes in synaptic plasticity are an important focus within neuroscience, little is known about ultrastructural changes of synaptic morphology during aging. Here we report how aging affects synaptic ultrastructure by using fluorescence and electron microscopy at the adult Drosophila neuromuscular junction (NMJ) of ventral abdominal muscles. Mainly four striking morphological changes of aging NMJs were revealed. 1) Bouton size increases with proportionally rising number of active zones (AZs). 2) Synaptic vesicle density at AZs is increased in old flies. 3) Late endosomes, cisternae, and multivesicular bodies accumulate in the presynaptic terminal, and vesicles accumulate between membranes of the terminal bouton and the subsynaptic reticulum. 4) The electron-dense pre- and postsynaptic apposition is expanded in aging NMJs, which is accompanied by an expansion of the postsynaptic glutamate receptor fields. These findings suggest that aging is possibly accompanied by impaired synaptic vesicle release and recycling and a potentially compensatory expansion of AZs and postsynaptic densities.
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Affiliation(s)
- Nicole Wagner
- Institute of Anatomy and Cell Biology, University of Wuerzburg, 97070, Wuerzburg, Germany
| | - Ulrike Laugks
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152, Martinsried, Germany
| | - Manfred Heckmann
- Institute of Physiology-Neurophysiology, Julius-Maximilians University Wuerzburg, 97070, Wuerzburg, Germany
| | - Esther Asan
- Institute of Anatomy and Cell Biology, University of Wuerzburg, 97070, Wuerzburg, Germany
| | - Kirsa Neuser
- Institute of Physiology-Neurophysiology, Julius-Maximilians University Wuerzburg, 97070, Wuerzburg, Germany
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22
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Huang S, Wang Y, Gan X, Fang D, Zhong C, Wu L, Hu G, Sosunov AA, McKhann GM, Yu H, Yan SS. Drp1-mediated mitochondrial abnormalities link to synaptic injury in diabetes model. Diabetes 2015; 64:1728-42. [PMID: 25412623 PMCID: PMC4407851 DOI: 10.2337/db14-0758] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 11/15/2014] [Indexed: 02/05/2023]
Abstract
Diabetes has adverse effects on the brain, especially the hippocampus, which is particularly susceptible to synaptic injury and cognitive dysfunction. The underlying mechanisms and strategies to rescue such injury and dysfunction are not well understood. Using a mouse model of type 2 diabetes (db/db mice) and a human neuronal cell line treated with high concentration of glucose, we demonstrate aberrant mitochondrial morphology, reduced ATP production, and impaired activity of complex I. These mitochondrial abnormalities are induced by imbalanced mitochondrial fusion and fission via a glycogen synthase kinase 3β (GSK3β)/dynamin-related protein-1 (Drp1)-dependent mechanism. Modulation of the Drp1 pathway or inhibition of GSK3β activity restores hippocampal long-term potentiation that is impaired in db/db mice. Our results point to a novel role for mitochondria in diabetes-induced synaptic impairment. Exploration of the mechanisms behind diabetes-induced synaptic deficit may provide a novel treatment for mitochondrial and synaptic injury in patients with diabetes.
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Affiliation(s)
- Shengbin Huang
- Department of Pharmacology & Toxicology and Higuchi Biosciences Center, School of Pharmacy, University of Kansas, Lawrence, KS State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yongfu Wang
- Department of Pharmacology & Toxicology and Higuchi Biosciences Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Xueqi Gan
- Department of Pharmacology & Toxicology and Higuchi Biosciences Center, School of Pharmacy, University of Kansas, Lawrence, KS State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Du Fang
- Department of Pharmacology & Toxicology and Higuchi Biosciences Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Changjia Zhong
- Department of Pharmacology & Toxicology and Higuchi Biosciences Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Long Wu
- Department of Pharmacology & Toxicology and Higuchi Biosciences Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Gang Hu
- Department of Pharmacology & Toxicology and Higuchi Biosciences Center, School of Pharmacy, University of Kansas, Lawrence, KS
| | - Alexander A Sosunov
- Department of Neurosurgery, College of Physicians and Surgeons, Columbia University, New York, NY
| | - Guy M McKhann
- Department of Neurosurgery, College of Physicians and Surgeons, Columbia University, New York, NY
| | - Haiyang Yu
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Shirley ShiDu Yan
- Department of Pharmacology & Toxicology and Higuchi Biosciences Center, School of Pharmacy, University of Kansas, Lawrence, KS
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Chandna AR, Nair M, Chang C, Pennington PR, Yamamoto Y, Mousseau DD, Campanucci VA. RAGE mediates the inactivation of nAChRs in sympathetic neurons under high glucose conditions. Eur J Neurosci 2014; 41:341-51. [PMID: 25431195 DOI: 10.1111/ejn.12795] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 10/27/2014] [Accepted: 10/28/2014] [Indexed: 12/11/2022]
Abstract
Autonomic dysfunction is a serious complication of diabetes and can lead to cardiovascular abnormalities and premature death. It was recently proposed that autonomic dysfunction is triggered by oxidation-mediated inactivation of neuronal nicotinic acetylcholine receptors (nAChRs), impairing synaptic transmission in sympathetic ganglia and resulting in autonomic failure. We investigated whether the receptor for advanced glycation end products (RAGE) and its role in the generation of reactive oxygen species (ROS) could be contributing to the events that initiate sympathetic malfunction under high glucose conditions. Using biochemical, live imaging and electrophysiological tools we demonstrated that exposure of sympathetic neurons to high glucose increases RAGE expression and oxidative markers, and that incubation with RAGE ligands (e.g. AGEs, S100 and HMGB1) mimics both ROS elevation and nAChR inactivation. In contrast, co-treatment with either antioxidants or an anti-RAGE IgG prevented the inactivation of nAChRs. Lastly, a role for RAGE in this context was corroborated by the lack of sensitivity of sympathetic neurons from RAGE knock-out mice to high glucose. These data define a pivotal role for RAGE in initiating the events associated with exposure of sympathetic neurons to high glucose, and strongly support RAGE signaling as a potential therapeutic target in the autonomic complications associated with diabetes.
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Affiliation(s)
- Andrew R Chandna
- Department of Physiology, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada
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Langdale C, Thor K, Marson L, Burgard E. Maintenance of bladder innervation in diabetes: A stereological study of streptozotocin-treated female rats. Auton Neurosci 2014; 185:59-66. [DOI: 10.1016/j.autneu.2014.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Revised: 06/23/2014] [Accepted: 06/24/2014] [Indexed: 12/19/2022]
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Synapses on sympathetic neurons and parasympathetic neurons differ in their vulnerability to diabetes. J Neurosci 2014; 34:8865-74. [PMID: 24966386 DOI: 10.1523/jneurosci.0033-14.2014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Synapses in autonomic ganglia represent the final output of various CNS structures that regulate the function of the periphery. Normally, these excitatory cholinergic-nicotinic synapses produce large suprathreshold EPSPs on sympathetic and parasympathetic neurons to convey signals from the CNS. However, in certain disease states, synaptic transmission in autonomic ganglia is depressed and the periphery becomes deregulated. For example, previous work demonstrated that hyperglycemia depresses EPSPs on sympathetic neurons and disrupts sympathetic reflexes by causing an ROS-dependent inactivation of the postsynaptic nAChRs. What is not clear, however, is whether some autonomic neurons are more vulnerable to hyperglycemia than others. One possibility is that sympathetic neurons may be more prone than cholinergic parasympathetic neurons to hyperglycemia-induced elevations in cytosolic ROS because sympathetic neurons contain several pro-oxidant molecules involved in noradrenaline metabolism. To test this hypothesis, we recorded synaptic transmission from different mouse sympathetic and parasympathetic ganglia, as well as from the adrenal medulla. In addition, we used cellular imaging to measure hyperglycemia-induced changes in cytosolic ROS and whole-cell recordings to measure the use-dependent rundown of ACh-evoked currents. Our results demonstrate that hyperglycemia depresses synaptic transmission on sympathetic neurons and adrenal chromaffin cells and elevates cytosolic ROS. Conversely, hyperglycemia has little effect on synaptic transmission at synapses on parasympathetic neurons. We conclude that sympathetic neurons and adrenal chromaffin cells are more vulnerable to diabetes than parasympathetic neurons, a finding that may have implications for both long-term diabetic autonomic neuropathies and insulin-induced hypoglycemia, a serious complication of diabetes.
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Menard CE, Durston M, Zherebitskaya E, Smith DR, Freed D, Glazner GW, Tian G, Fernyhough P, Arora RC. Temporal dystrophic remodeling within the intrinsic cardiac nervous system of the streptozotocin-induced diabetic rat model. Acta Neuropathol Commun 2014; 2:60. [PMID: 24894521 PMCID: PMC4229951 DOI: 10.1186/2051-5960-2-60] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/19/2014] [Indexed: 01/20/2023] Open
Abstract
Introduction The pathogenesis of heart failure (HF) in diabetic individuals, called “diabetic cardiomyopathy”, is only partially understood. Alterations in the cardiac autonomic nervous system due to oxidative stress have been implicated. The intrinsic cardiac nervous system (ICNS) is an important regulatory pathway of cardiac autonomic function, however, little is known about the alterations that occur in the ICNS in diabetes. We sought to characterize morphologic changes and the role of oxidative stress within the ICNS of diabetic hearts. Cultured ICNS neuronal cells from the hearts of 3- and 6-month old type 1 diabetic streptozotocin (STZ)-induced diabetic Sprague-Dawley rats and age-matched controls were examined. Confocal microscopy analysis for protein gene product 9.5 (PGP 9.5) and amino acid adducts of (E)-4-hydroxy-2-nonenal (4-HNE) using immunofluorescence was undertaken. Cell morphology was then analyzed in a blinded fashion for features of neuronal dystrophy and the presence of 4-HNE adducts. Results At 3-months, diabetic ICNS neuronal cells exhibited 30% more neurite swellings per area (p = 0.01), and had a higher proportion with dystrophic appearance (88.1% vs. 50.5%; p = <0.0001), as compared to control neurons. At 6-months, diabetic ICNS neurons exhibited more features of dystrophy as compared to controls (74.3% vs. 62.2%; p = 0.0448), with 50% more neurite branching (p = 0.0015) and 50% less neurite outgrowth (p = <0.001). Analysis of 4-HNE adducts in ICNS neurons of 6-month diabetic rats demonstrated twice the amount of reactive oxygen species (ROS) as compared to controls (p = <0.001). Conclusion Neuronal dystrophy occurs in the ICNS neurons of STZ-induced diabetic rats, and accumulates temporally within the disease process. In addition, findings implicate an increase in ROS within the neuronal processes of ICNS neurons of diabetic rats suggesting an association between oxidative stress and the development of dystrophy in cardiac autonomic neurons.
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Abstract
Autonomic neuropathy complicates diabetes by increasing patient morbidity and mortality. Surprisingly, considering its importance, development and exploitation of animal models has lagged behind the wealth of information collected for somatic symmetrical sensory neuropathy. Nonetheless, animal studies have resulted in a variety of insights into the pathogenesis, neuropathology, and pathophysiology of diabetic autonomic neuropathy (DAN) with significant and, in some cases, remarkable correspondence between rodent models and human disease. Particularly in the study of alimentary dysfunction, findings in intrinsic intramural ganglia, interstitial cells of Cajal and the extrinsic parasympathetic and sympathetic ganglia serving the bowel vie for recognition as the chief mechanism. A body of work focused on neuropathologic findings in experimental animals and human subjects has demonstrated that axonal and dendritic pathology in sympathetic ganglia with relative neuron preservation represents one of the neuropathologic hallmarks of DAN but it is unlikely to represent the entire story. There is a surprising selectivity of the diabetic process for subpopulations of neurons and nerve terminals within intramural, parasympathetic, and sympathetic ganglia and innervation of end organs, afflicting some while sparing others, and differing between vascular and other targets within individual end organs. Rather than resulting from a simple deficit in one limb of an effector pathway, autonomic dysfunction may proceed from the inability to integrate portions of several complex pathways. The selectivity of the diabetic process appears to confound a simple global explanation (e.g., ischemia) of DAN. Although the search for a single unifying pathogenetic hypothesis continues, it is possible that autonomic neuropathy will have multiple pathogenetic mechanisms whose interplay may require therapies consisting of a cocktail of drugs. The role of multiple neurotrophic substances, antioxidants (general or pathway specific), inhibitors of formation of advanced glycosylation end products and drugs affecting the polyol pathway may be complex and therapeutic elements may have both salutary and untoward effects. This review has attempted to present the background and current findings and hypotheses, focusing on autonomic elements including and beyond the typical parasympathetic and sympathetic nervous systems to include visceral sensory and enteric nervous systems.
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Affiliation(s)
- Robert E Schmidt
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO, USA.
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Pathogenesis of autosomal dominant hereditary spastic paraplegia (SPG6) revealed by a rat model. J Neuropathol Exp Neurol 2013; 72:1016-28. [PMID: 24128679 PMCID: PMC3814936 DOI: 10.1097/nen.0000000000000000] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Supplemental Digital Content is available in the text. Hereditary spastic paraplegias (HSPs) are characterized by progressive spasticity and weakness in the lower extremities that result from length-dependent central to peripheral axonal degeneration. Mutations in the non-imprinted Prader-Willi/Angelman syndrome locus 1 (NIPA1) transmembrane protein cause an autosomal dominant form of HSP (SPG6). Here, we report that transgenic (Tg) rats expressing a human NIPA1/SPG6 mutation in neurons (Thy1.2-hNIPA1G106R) show marked early onset behavioral and electrophysiologic abnormalities. Detailed morphologic analyses reveal unique histopathologic findings, including the accumulation of tubulovesicular organelles with endosomal features that start at axonal and dendritic terminals, followed by multifocal vacuolar degeneration in both the CNS and peripheral nerves. In addition, the NIPA1G106R mutation in the spinal cord from older Tg rats results in an increase in bone morphogenetic protein type II receptor expression, suggesting that its degradation is impaired. This Thy1.2-hNIPA1G106R Tg rat model may serve as a valuable tool for understanding endosomal trafficking in the pathogenesis of a subgroup of HSP with an abnormal interaction with bone morphogenetic protein type II receptor, as well as for developing potential therapeutic strategies for diseases with axonal degeneration and similar pathogenetic mechanisms.
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Vinsant S, Mansfield C, Jimenez-Moreno R, Del Gaizo Moore V, Yoshikawa M, Hampton TG, Prevette D, Caress J, Oppenheim RW, Milligan C. Characterization of early pathogenesis in the SOD1(G93A) mouse model of ALS: part II, results and discussion. Brain Behav 2013; 3:431-57. [PMID: 24381813 PMCID: PMC3869683 DOI: 10.1002/brb3.142] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 03/21/2013] [Accepted: 03/22/2013] [Indexed: 12/12/2022] Open
Abstract
Pathological events are well characterized in amyotrophic lateral sclerosis (ALS) mouse models, but review of the literature fails to identify a specific initiating event that precipitates disease pathology. There is now growing consensus in the field that axon and synapses are first cellular sites of degeneration, but controversy exists over whether axon and synapse loss is initiated autonomously at those sites or by pathology in the cell body, in nonneuronal cells or even in nonmotoneurons (MNs). Previous studies have identified pathological events in the mutant superoxide dismutase 1 (SOD1) models involving spinal cord, peripheral axons, neuromuscular junctions (NMJs), or muscle; however, few studies have systematically examined pathogenesis at multiple sites in the same study. We have performed ultrastructural examination of both central and peripheral components of the neuromuscular system in the SOD1(G93A) mouse model of ALS. Twenty percent of MNs undergo degeneration by P60, but NMJ innervation in fast fatigable muscles is reduced by 40% by P30. Gait alterations and muscle weakness were also found at P30. There was no change in axonal transport prior to initial NMJ denervation. Mitochondrial morphological changes are observed at P7 and become more prominent with disease progression. At P30 there was a significant decrease in excitatory axo-dendritic and axo-somatic synapses with an increase in C-type axo-somatic synapses. Our study examined early pathology in both peripheral and central neuromuscular system. The muscle denervation is associated with functional motor deficits and begins during the first postnatal month in SOD1(G93A) mice. Physiological dysfunction and pathology in the mitochondria of synapses and MN soma and dendrites occur, and disease onset in these animals begins more than 2 months earlier than originally thought. This information may be valuable for designing preclinical trials that are more likely to impact disease onset and progression.
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Affiliation(s)
- Sharon Vinsant
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Carol Mansfield
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Ramon Jimenez-Moreno
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | | | - Masaaki Yoshikawa
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | | | - David Prevette
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - James Caress
- Department of Neurology and the ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Ronald W Oppenheim
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
| | - Carol Milligan
- Department of Neurobiology and Anatomy, The Neuroscience Program and The ALS Center, Wake Forest University School of Medicine Winston-Salem, North Carolina
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Mulay SR, Kulkarni OP, Rupanagudi KV, Migliorini A, Darisipudi MN, Vilaysane A, Muruve D, Shi Y, Munro F, Liapis H, Anders HJ. Calcium oxalate crystals induce renal inflammation by NLRP3-mediated IL-1β secretion. J Clin Invest 2012. [PMID: 23221343 DOI: 10.1172/jci636679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Nephrocalcinosis, acute calcium oxalate (CaOx) nephropathy, and renal stone disease can lead to inflammation and subsequent renal failure, but the underlying pathological mechanisms remain elusive. Other crystallopathies, such as gout, atherosclerosis, and asbestosis, trigger inflammation and tissue remodeling by inducing IL-1β secretion, leading us to hypothesize that CaOx crystals may induce inflammation in a similar manner. In mice, intrarenal CaOx deposition induced tubular damage, cytokine expression, neutrophil recruitment, and renal failure. We found that CaOx crystals activated murine renal DCs to secrete IL-1β through a pathway that included NLRP3, ASC, and caspase-1. Despite a similar amount of crystal deposits, intrarenal inflammation, tubular damage, and renal dysfunction were abrogated in mice deficient in MyD88; NLRP3, ASC, and caspase-1; IL-1R; or IL-18. Nephropathy was attenuated by DC depletion, ATP depletion, or therapeutic IL-1 antagonism. These data demonstrated that CaOx crystals trigger IL-1β-dependent innate immunity via the NLRP3/ASC/caspase-1 axis in intrarenal mononuclear phagocytes and directly damage tubular cells, leading to the release of the NLRP3 agonist ATP. Furthermore, these results suggest that IL-1β blockade may prevent renal damage in nephrocalcinosis.
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Affiliation(s)
- Shrikant R Mulay
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Germany
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Mulay SR, Kulkarni OP, Rupanagudi KV, Migliorini A, Darisipudi MN, Vilaysane A, Muruve D, Shi Y, Munro F, Liapis H, Anders HJ. Calcium oxalate crystals induce renal inflammation by NLRP3-mediated IL-1β secretion. J Clin Invest 2012; 123:236-46. [PMID: 23221343 DOI: 10.1172/jci63679] [Citation(s) in RCA: 326] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 10/11/2012] [Indexed: 12/11/2022] Open
Abstract
Nephrocalcinosis, acute calcium oxalate (CaOx) nephropathy, and renal stone disease can lead to inflammation and subsequent renal failure, but the underlying pathological mechanisms remain elusive. Other crystallopathies, such as gout, atherosclerosis, and asbestosis, trigger inflammation and tissue remodeling by inducing IL-1β secretion, leading us to hypothesize that CaOx crystals may induce inflammation in a similar manner. In mice, intrarenal CaOx deposition induced tubular damage, cytokine expression, neutrophil recruitment, and renal failure. We found that CaOx crystals activated murine renal DCs to secrete IL-1β through a pathway that included NLRP3, ASC, and caspase-1. Despite a similar amount of crystal deposits, intrarenal inflammation, tubular damage, and renal dysfunction were abrogated in mice deficient in MyD88; NLRP3, ASC, and caspase-1; IL-1R; or IL-18. Nephropathy was attenuated by DC depletion, ATP depletion, or therapeutic IL-1 antagonism. These data demonstrated that CaOx crystals trigger IL-1β-dependent innate immunity via the NLRP3/ASC/caspase-1 axis in intrarenal mononuclear phagocytes and directly damage tubular cells, leading to the release of the NLRP3 agonist ATP. Furthermore, these results suggest that IL-1β blockade may prevent renal damage in nephrocalcinosis.
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Affiliation(s)
- Shrikant R Mulay
- Nephrologisches Zentrum, Medizinische Klinik und Poliklinik IV, Klinikum der Universität München, Munich, Germany
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Hernández-Beltrán N, Moreno CB, Gutiérrez-Álvarez AM. Contribution of mitochondria to pain in diabetic neuropathy. ACTA ACUST UNITED AC 2012; 60:25-32. [PMID: 22595537 DOI: 10.1016/j.endonu.2012.03.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 03/10/2012] [Accepted: 03/19/2012] [Indexed: 01/13/2023]
Abstract
Diabetes is a metabolic disease affecting approximately 300 million people worldwide. Neuropathy is one of its frequent complications, and may affect sensory, motor, and autonomic nerves. Its pathophysiology has not fully been elucidated. Several hypotheses have been proposed, and mitochondria have been suggested to play a significant role. This article reviews the mechanisms involved in mitochondrial dysfunction and development of diabetic neuropathy, consisting mainly of oxidative and inflammatory stress, changes in intracellular calcium regulation, apoptotic processes, and changes in mitochondrial structure and function that may lead to development of diabetic neuropathy.
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Chowdhury SKR, Smith DR, Fernyhough P. The role of aberrant mitochondrial bioenergetics in diabetic neuropathy. Neurobiol Dis 2012; 51:56-65. [PMID: 22446165 DOI: 10.1016/j.nbd.2012.03.016] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 02/22/2012] [Accepted: 03/01/2012] [Indexed: 02/07/2023] Open
Abstract
Diabetic neuropathy is a neurological complication of diabetes that causes significant morbidity and, because of the obesity-driven rise in incidence of type 2 diabetes, is becoming a major international health problem. Mitochondrial phenotype is abnormal in sensory neurons in diabetes and may contribute to the etiology of diabetic neuropathy where a distal dying-back neurodegenerative process is a key component contributing to fiber loss. This review summarizes the major features of mitochondrial dysfunction in neurons and Schwann cells in human diabetic patients and in experimental animal models (primarily exhibiting type 1 diabetes). This article attempts to relate these findings to the development of critical neuropathological hallmarks of the disease. Recent work reveals that hyperglycemia in diabetes triggers nutrient excess in neurons that, in turn, mediates a phenotypic change in mitochondrial biology through alteration of the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) signaling axis. This vital energy sensing metabolic pathway modulates mitochondrial function, biogenesis and regeneration. The bioenergetic phenotype of mitochondria in diabetic neurons is aberrant due to deleterious alterations in expression and activity of respiratory chain components as a direct consequence of abnormal AMPK/PGC-1α signaling. Utilization of innovative respirometry equipment to analyze mitochondrial function of cultured adult sensory neurons from diabetic rodents shows that the outcome for cellular bioenergetics is a reduced adaptability to fluctuations in ATP demand. The diabetes-induced maladaptive process is hypothesized to result in exhaustion of the ATP supply in the distal nerve compartment and induction of nerve fiber dissolution. The role of mitochondrial dysfunction in the etiology of diabetic neuropathy is compared with other types of neuropathy with a distal dying-back pathology such as Friedreich ataxia, Charcot-Marie-Tooth disease type 2 and human immunodeficiency virus-associated distal-symmetric neuropathy.
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Affiliation(s)
- Subir K Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, Winnipeg, MB, Canada
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Von Bartheld CS, Altick AL. Multivesicular bodies in neurons: distribution, protein content, and trafficking functions. Prog Neurobiol 2011; 93:313-40. [PMID: 21216273 DOI: 10.1016/j.pneurobio.2011.01.003] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 12/22/2010] [Accepted: 01/03/2011] [Indexed: 11/27/2022]
Abstract
Multivesicular bodies (MVBs) are intracellular endosomal organelles characterized by multiple internal vesicles that are enclosed within a single outer membrane. MVBs were initially regarded as purely prelysosomal structures along the degradative endosomal pathway of internalized proteins. MVBs are now known to be involved in numerous endocytic and trafficking functions, including protein sorting, recycling, transport, storage, and release. This review of neuronal MVBs summarizes their research history, morphology, distribution, accumulation of cargo and constitutive proteins, transport, and theories of functions of MVBs in neurons and glia. Due to their complex morphologies, neurons have expanded trafficking and signaling needs, beyond those of "geometrically simpler" cells, but it is not known whether neuronal MVBs perform additional transport and signaling functions. This review examines the concept of compartment-specific MVB functions in endosomal protein trafficking and signaling within synapses, axons, dendrites and cell bodies. We critically evaluate reports of the accumulation of neuronal MVBs based on evidence of stress-induced MVB formation. Furthermore, we discuss potential functions of neuronal and glial MVBs in development, in dystrophic neuritic syndromes, injury, disease, and aging. MVBs may play a role in Alzheimer's, Huntington's, and Niemann-Pick diseases, some types of frontotemporal dementia, prion and virus trafficking, as well as in adaptive responses of neurons to trauma and toxin or drug exposure. Functions of MVBs in neurons have been much neglected, and major gaps in knowledge currently exist. Developing truly MVB-specific markers would help to elucidate the roles of neuronal MVBs in intra- and intercellular signaling of normal and diseased neurons.
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Affiliation(s)
- Christopher S Von Bartheld
- Department of Physiology and Cell Biology, Mailstop 352, University of Nevada School of Medicine, Reno, NV 89557, USA.
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Campanucci V, Krishnaswamy A, Cooper E. Diabetes depresses synaptic transmission in sympathetic ganglia by inactivating nAChRs through a conserved intracellular cysteine residue. Neuron 2010; 66:827-34. [PMID: 20620869 DOI: 10.1016/j.neuron.2010.06.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2010] [Indexed: 10/19/2022]
Abstract
Most people with diabetes develop severe complications of the autonomic nervous system; yet, the underlying causes of many diabetic-induced dysautonomias are poorly understood. Here we explore the idea that these dysautonomias results, in part, from a defect in synaptic transmission. To test this idea, we investigated cultured sympathetic neurons and show that hyperglycemia inactivates nAChRs through a mechanism involving an elevation in reactive oxygen species and an interaction with highly conserved cysteine residues located near the intracellular mouth of the nAChR channel. Consistent with this, we show that diabetic mice have depressed ganglionic transmission and reduced sympathetic reflexes, whereas diabetic mice expressing mutant postsynaptic nAChRs that lack the conserved cysteine residues on the alpha3 subunit have normal synaptic transmission in sympathetic ganglia and normal sympathetic reflexes. Our work suggests a new model for diabetic-induced dysautonomias and identifies ganglionic nAChRs as targets of hyperglycemia-induced downstream signals.
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Affiliation(s)
- Verónica Campanucci
- Department of Physiology, McGill University, Montreal, Quebec H3G 1Y6, Canada
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Fernyhough P, Roy Chowdhury SK, Schmidt RE. Mitochondrial stress and the pathogenesis of diabetic neuropathy. Expert Rev Endocrinol Metab 2010; 5:39-49. [PMID: 20729997 PMCID: PMC2924887 DOI: 10.1586/eem.09.55] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Diabetic neuropathy is a major complication of diabetes that affects the sensory and autonomic nervous systems and leads to significant morbidity and impact on quality of life of patients. Mitochondrial stress has been proposed as a major mediator of neurodegeneration in diabetes. This review briefly summarizes the nature of sensory and autonomic nerve dysfunction and presents these findings in the context of diabetes-induced nerve degeneration mediated by alterations in mitochondrial ultrastructure, physiology and trafficking. Diabetes-induced dysfunction in calcium homeostasis is discussed at length and causative associations with sub-optimal mitochondrial physiology are developed. It is clear that across a range of complications of diabetes that mitochondrial physiology is impaired, in general a reduction in electron transport chain capability is apparent. This abnormal activity may predispose mitochondria to generate elevated reactive oxygen species (ROS), although experimental proof remains lacking, but more importantly will deleteriously alter the bioenergetic status of neurons. It is proposed that the next five years of research should focus on identifying changes in mitochondrial phenotype and associated cellular impact, identifying sources of ROS in neurons and analyzing mitochondrial trafficking under diabetic conditions.
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Affiliation(s)
- Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Research Centre, R4046 - 351 Taché Avenue, Winnipeg, MB R2H 2A6, Canada and Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada, Tel: (204) 235 3692
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Rossi S, Furlan R, De Chiara V, Musella A, Lo Giudice T, Mataluni G, Cavasinni F, Cantarella C, Bernardi G, Muzio L, Martorana A, Martino G, Centonze D. Exercise attenuates the clinical, synaptic and dendritic abnormalities of experimental autoimmune encephalomyelitis. Neurobiol Dis 2009; 36:51-9. [PMID: 19591937 DOI: 10.1016/j.nbd.2009.06.013] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Revised: 06/25/2009] [Accepted: 06/28/2009] [Indexed: 11/18/2022] Open
Abstract
Voluntary exercise is beneficial in models of primarily neurodegenerative disorders. Whether exercise also affects inflammatory neurodegeneration is unknown. In the present study, we evaluated the clinical, synaptic and neuropathological effects of voluntary wheel running in mice with myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE), a model of multiple sclerosis. Exercising EAE mice exhibited less severe neurological deficits compared to control EAE animals. The sensitivity of striatal GABA synapses to the stimulation of cannabinoid CB1 receptors was dramatically downregulated following EAE induction, and was rescued by exercise in EAE mice with access to a running wheel. Finally, we found that exercise was able to contrast dendritic spine loss induced by EAE in striatal neurons, although the degree of inflammatory response was similar in the two experimental groups. Our work suggests that life style and experiences can impact the clinical course of inflammatory neurodegenerative diseases by affecting their synaptic bases.
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MESH Headings
- Animals
- Antigens, CD/metabolism
- Corpus Striatum/pathology
- Dendrites/pathology
- Dendrites/physiology
- Dendrites/ultrastructure
- Disease Models, Animal
- Dronabinol/analogs & derivatives
- Dronabinol/pharmacology
- Encephalomyelitis, Autoimmune, Experimental/chemically induced
- Encephalomyelitis, Autoimmune, Experimental/complications
- Encephalomyelitis, Autoimmune, Experimental/pathology
- Encephalomyelitis, Autoimmune, Experimental/rehabilitation
- Female
- Glutamic Acid/metabolism
- Glutamic Acid/pharmacology
- Glycoproteins
- In Vitro Techniques
- Mice
- Mice, Inbred C57BL
- Movement Disorders/etiology
- Myelin-Oligodendrocyte Glycoprotein
- Neurons/pathology
- Neurons/physiology
- Neuroprotective Agents/pharmacology
- Patch-Clamp Techniques/methods
- Peptide Fragments
- Physical Conditioning, Animal
- Silver Staining/methods
- Statistics, Nonparametric
- Synapses/physiology
- Synapses/ultrastructure
- Synaptic Potentials/drug effects
- Synaptic Potentials/physiology
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Affiliation(s)
- Silvia Rossi
- Clinica Neurologica, Dipartimento di Neuroscienze, Università Tor Vergata, Via Montpellier 1, 00133 Rome, Italy
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Ai J, Wurster RD, Harden SW, Cheng ZJ. Vagal afferent innervation and remodeling in the aortic arch of young-adult fischer 344 rats following chronic intermittent hypoxia. Neuroscience 2009; 164:658-66. [PMID: 19580847 DOI: 10.1016/j.neuroscience.2009.06.066] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 06/15/2009] [Accepted: 06/29/2009] [Indexed: 11/25/2022]
Abstract
Previously, we have shown that chronic intermittent hypoxia (CIH) impairs baroreflex control of heart rate and augments aortic baroreceptor afferent function. In the present study, we examined whether CIH induces structural changes of aortic afferent axons and terminals. Young-adult Fischer 344 (F344, 4 months old) rats were exposed to room air (RA) or CIH for 35-45 days. After 14-24 days of exposure, they received tracer DiI injection into the left nodose ganglion to anterogradely label vagal afferent nerves. After surgery, animals were returned to their cages to continue RA or CIH exposure. Twenty-one days after DiI injection, the animals were sacrificed and the aortic arch was examined using confocal microscopy. In both RA and CIH rats, we found that DiI-labeled vagal afferent axons entered the wall of the aortic arch, then fanned out and branched into large receptive fields with numerous terminals (flower-sprays, end-nets and free endings). Vagal afferent axons projected much more to the anterior wall than to the posterior wall. In general, the flower-sprays, end-nets and free endings were widely and similarly distributed in the aortic arch of both groups. However, several salient differences between RA and CIH rats were found. Compared to RA control, CIH rats appeared to have larger vagal afferent receptive fields. The CIH rats had many abnormal flower-sprays, end-nets, and free endings which were intermingled and diffused into "bush-like" structures. However, the total number of flower-sprays was comparable (P>0.05). Since there was a large variance of the size of flower-sprays, we only sampled the 10 largest flower-sprays from each animal. CIH substantially increased the size of large flower-sprays (P<0.01). Numerous free endings with enlarged varicosities were identified, resembling axonal sprouting structures. Taken together, our data indicate that CIH induces significant remodeling of afferent terminal structures in the aortic arch of F344 rats. We suggest that such an enlargement of vagal afferent terminals may contribute to altered aortic baroreceptor function following CIH.
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Affiliation(s)
- J Ai
- Biomolecular Science Center, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, 4000 Central Florida Boulevard, Orlando, FL 32816, USA
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Schmidt RE, Green KG, Snipes LL, Feng D. Neuritic dystrophy and neuronopathy in Akita (Ins2(Akita)) diabetic mouse sympathetic ganglia. Exp Neurol 2009; 216:207-18. [PMID: 19111542 PMCID: PMC2672346 DOI: 10.1016/j.expneurol.2008.11.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2008] [Revised: 11/24/2008] [Accepted: 11/30/2008] [Indexed: 12/14/2022]
Abstract
Diabetic autonomic neuropathy is a debilitating, poorly studied complication of diabetes. Our previous studies of non-obese diabetic (NOD) and related mouse models identified rapidly developing, dramatic pathology in prevertebral sympathetic ganglia; however, once diabetic, the mice did not survive for extended periods needed to examine the ability of therapeutic agents to correct established neuropathy. In the current manuscript we show that the Akita (Ins2(Akita)) mouse is a robust model of diabetic sympathetic autonomic neuropathy with unambiguous, spontaneous, rapidly-developing neuropathology which corresponds closely to the characteristic pathology of other rodent models and man. Akita mice diabetic for 2, 4 or 8 months of diabetes progressively developed markedly swollen axons and dendrites ("neuritic dystrophy") in the prevertebral superior mesenteric (SMG) and celiac ganglia (CG). Comparable changes failed to develop in the superior cervical ganglia (SCG) of the Akita mouse or in any ganglia of non-diabetic mice. Morphometric studies demonstrate an overall increase in presynaptic axon terminal cross sectional area, including those without any ultrastructural features of dystrophy. Neurons in Akita mouse prevertebral sympathetic ganglia show an unusual perikaryal alteration characterized by the accumulation of membranous aggregates and minute mitochondria and loss of rough endoplasmic reticulum. These changes result in the loss of a third of neurons in the CG over the course of 8 months of diabetes. The extended survival of diabetic mice and robust pathologic findings provide a clinically relevant paradigm that will facilitate the analysis of novel therapeutic agents on the reversal of autonomic neuropathy.
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Affiliation(s)
- Robert E Schmidt
- Division of Neuropathology, Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO 63110, USA.
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