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Kang N, Han X, Li Z, Liu T, Mi X, Li Y, Guo X, Han D, Yang N. Rapamycin Affects the Hippocampal SNARE Complex to Alleviate Cognitive Dysfunction Induced by Surgery in Aged Rats. Brain Sci 2023; 13:598. [PMID: 37190563 PMCID: PMC10136734 DOI: 10.3390/brainsci13040598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 03/03/2023] [Accepted: 03/22/2023] [Indexed: 04/05/2023] Open
Abstract
Delayed neurocognitive recovery (dNCR) is a common complication that occurs post-surgery, especially in elderly individuals. The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex plays an essential role in various membrane fusion events, such as synaptic vesicle exocytosis and autophagosome-lysosome fusion. Although SNARE complex dysfunction has been observed in several neurodegenerative disorders, the causal link between SNARE-mediated membrane fusion and dNCR remains unclear. We previously demonstrated that surgical stimuli caused cognitive impairment in aged rats by inducing α-synuclein accumulation, inhibiting autophagy, and disrupting neurotransmitter release in hippocampal synaptosomes. Here, we evaluated the effects of propofol anesthesia plus surgery on learning and memory and investigated levels of SNARE proteins and chaperones in hippocampal synaptosomes. Aged rats that received propofol anesthesia and surgery exhibited learning and memory impairments in a Morris water maze test and decreased levels of synaptosome-associated protein 25, synaptobrevin/vesicle-associated membrane protein 2, and syntaxin 1. Levels of SNARE chaperones, including mammalian uncoordinated-18, complexins 1 and 2, cysteine string protein-α, and N-ethylmaleimide-sensitive factor, were all significantly decreased following anesthesia with surgical stress. However, the synaptic vesicle marker synaptophysin was unaffected. The autophagy-enhancer rapamycin attenuated structural and functional disturbances of the SNARE complex and ameliorated disrupted neurotransmitter release. Our results indicate that perturbations of SNARE proteins in hippocampal synaptosomes may underlie the occurrence of dNCR. Moreover, the protective effect of rapamycin may partially occur through recovery of SNARE structural and functional abnormalities. Our findings provide insight into the molecular mechanisms underlying dNCR.
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Affiliation(s)
- Ning Kang
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Xiaoguang Han
- Department of Spine Surgery, Beijing Jishuitan Hospital, Beijing 100035, China
- Department of Spine Surgery, Peking University Fourth School of Clinical Medicine, Beijing 100035, China
- Beijing Key Laboratory of Robotic Orthopaedics, Beijing 100035, China
| | - Zhengqian Li
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Taotao Liu
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Xinning Mi
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Yue Li
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Xiangyang Guo
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Dengyang Han
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
| | - Ning Yang
- Department of Anesthesiology, Peking University Third Hospital, Beijing 100191, China
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2
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Costa AS, Ferri E, Guerini FR, Rossi PD, Arosio B, Clerici M. VAMP2 Expression and Genotype Are Possible Discriminators in Different Forms of Dementia. Front Aging Neurosci 2022; 14:858162. [PMID: 35360211 PMCID: PMC8964122 DOI: 10.3389/fnagi.2022.858162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 02/22/2022] [Indexed: 12/03/2022] Open
Abstract
Vascular alterations often overlap with neurodegeneration, resulting in mixed forms of dementia (MD) that are hard to differentiate from Alzheimer’s Disease (AD). The 26 bp intergenic polymorphism of VAMP2, a key component of SNARE complex, as well as its mRNA and protein levels are associated with neurological diseases. We evaluated ApoE4 and VAMP2 26 bp Ins/Del genotype distribution in 177 AD, 132 MD, 115 Mild Cognitive Impairment (MCI) and 250 individuals without cognitive decline (CT), as well as VAMP2 gene expression in a subset of 73 AD, 122 MD, 103 MCI and 140 CT. Forty-two MCI evolved to AD (22 MCI-AD) or MD (20 MCI-MD) over time. VAMP2 mRNA was higher in MD compared to AD (p = 0.0013) and CT (p = 0.0017), and in MCI-MD compared to MCI-AD (p < 0.001) after correcting for age, gender, MMSE and ApoE4 +/− covariates (pc = 0.004). A higher VAMP2 expression was observed in subjects carrying the minor allele Del compared to those carrying the Ins/Ins genotype (p = 0.012). Finally, Del/Del genotype was more frequently carried by MD/MCI-MD compared to CT (pc = 0.036). These results suggest that VAMP2 mRNA expression can discriminate mixed form of dementia from AD, possibly being a biomarker of AD evolution in MCI patients.
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Affiliation(s)
| | - Evelyn Ferri
- Geriatric Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Franca Rosa Guerini
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
- *Correspondence: Franca Rosa Guerini,
| | - Paolo Dionigi Rossi
- Geriatric Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Beatrice Arosio
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Mario Clerici
- IRCCS Fondazione Don Carlo Gnocchi ONLUS, Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, Milan, Italy
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3
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Cho TS, Beigaitė E, Klein NE, Sweeney ST, Bhattacharya MRC. The Putative Drosophila TMEM184B Ortholog Tmep Ensures Proper Locomotion by Restraining Ectopic Firing at the Neuromuscular Junction. Mol Neurobiol 2022; 59:2605-2619. [PMID: 35107803 PMCID: PMC9018515 DOI: 10.1007/s12035-022-02760-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 01/20/2022] [Indexed: 11/29/2022]
Abstract
TMEM184B is a putative seven-pass membrane protein that promotes axon degeneration after injury. TMEM184B mutation causes aberrant neuromuscular architecture and sensory and motor behavioral defects in mice. The mechanism through which TMEM184B causes neuromuscular defects is unknown. We employed Drosophila melanogaster to investigate the function of the closely related gene, Tmep (CG12004), at the neuromuscular junction. We show that Tmep is required for full adult viability and efficient larval locomotion. Tmep mutant larvae have a reduced body contraction rate compared to controls, with stronger deficits in females. In recordings from body wall muscles, Tmep mutants show substantial hyperexcitability, with many postsynaptic potentials fired in response to a single stimulation, consistent with a role for Tmep in restraining synaptic excitability. Additional branches and satellite boutons at Tmep mutant neuromuscular junctions are consistent with an activity-dependent synaptic overgrowth. Tmep is expressed in endosomes and synaptic vesicles within motor neurons, suggesting a possible role in synaptic membrane trafficking. Using RNAi knockdown, we show that Tmep is required in motor neurons for proper larval locomotion and excitability, and that its reduction increases levels of presynaptic calcium. Locomotor defects can be rescued by presynaptic knockdown of endoplasmic reticulum calcium channels or by reducing evoked release probability, further suggesting that excess synaptic activity drives behavioral deficiencies. Our work establishes a critical function for Tmep in the regulation of synaptic transmission and locomotor behavior.
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Affiliation(s)
- Tiffany S Cho
- Department of Neuroscience, University of Arizona, 1040 E 4th Street, Tucson, AZ, 85721, USA
| | - Eglė Beigaitė
- Department of Biology, University of York, York, YO10 5DD, UK.,York Biomedical Research Institute, University of York, York, YO10 5DD, UK
| | - Nathaniel E Klein
- Department of Neuroscience, University of Arizona, 1040 E 4th Street, Tucson, AZ, 85721, USA
| | - Sean T Sweeney
- Department of Biology, University of York, York, YO10 5DD, UK.,York Biomedical Research Institute, University of York, York, YO10 5DD, UK
| | - Martha R C Bhattacharya
- Department of Neuroscience, University of Arizona, 1040 E 4th Street, Tucson, AZ, 85721, USA.
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4
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Christmann A, Gries M, Scholz P, Stahr PL, Law JKY, Schulte S, Martin M, Lilischkis R, Ingebrandt S, Keck CM, Schäfer KH. The antioxidant Rutin counteracts the pathological impact of α-synuclein on the enteric nervous system in vitro. Biol Chem 2021; 403:103-122. [PMID: 34582634 DOI: 10.1515/hsz-2021-0259] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 09/15/2021] [Indexed: 11/15/2022]
Abstract
Motoric disturbances in Parkinson's disease (PD) derive from the loss of dopaminergic neurons in the substantia nigra. Intestinal dysfunctions often appear long before manifestation of neuronal symptoms, suggesting a strong correlation between gut and brain in PD. Oxidative stress is a key player in neurodegeneration causing neuronal cell death. Using natural antioxidative flavonoids like Rutin, might provide intervening strategies to improve PD pathogenesis. To explore the potential effects of micro (mRutin) compared to nano Rutin (nRutin) upon the brain and the gut during PD, its neuroprotective effects were assessed using an in vitro PD model. Our results demonstrated that Rutin inhibited the neurotoxicity induced by A53T α-synuclein (Syn) administration by decreasing oxidized lipids and increasing cell viability in both, mesencephalic and enteric cells. For enteric cells, neurite outgrowth, number of synaptic vesicles, and tyrosine hydroxylase positive cells were significantly reduced when treated with Syn. This could be reversed by the addition of Rutin. nRutin revealed a more pronounced result in all experiments. In conclusion, our study shows that Rutin, especially the nanocrystals, are promising natural compounds to protect neurons from cell death and oxidative stress during PD. Early intake of Rutin may provide a realizable option to prevent or slow PD pathogenesis.
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Affiliation(s)
- Anne Christmann
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, D-66482Zweibrücken, Germany
| | - Manuela Gries
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, D-66482Zweibrücken, Germany
| | - Patrik Scholz
- Formulation Development, BAYER AG, R&D, D-51373Leverkusen, Germany
| | - Pascal L Stahr
- Department of Pharmaceutics and Biopharmaceutics, Philipps-Universität Marburg, D-35037Marburg, Germany
| | - Jessica Ka Yan Law
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, D-66482Zweibrücken, Germany
| | - Steven Schulte
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, D-66482Zweibrücken, Germany
| | - Monika Martin
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, D-66482Zweibrücken, Germany
| | - Rainer Lilischkis
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, D-66482Zweibrücken, Germany
| | - Sven Ingebrandt
- Institute of Materials in Electrical Engineering, RWTH Aachen University, D-52074Aachen, Germany
| | - Cornelia M Keck
- Department of Pharmaceutics and Biopharmaceutics, Philipps-Universität Marburg, D-35037Marburg, Germany
| | - Karl-Herbert Schäfer
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, D-66482Zweibrücken, Germany.,Department of Pediatric Surgery, Medical Faculty Mannheim, University of Heidelberg, D-68167Mannheim, Germany
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5
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Chanaday NL, Kavalali ET. Synaptobrevin-2 dependent regulation of single synaptic vesicle endocytosis. Mol Biol Cell 2021; 32:1818-1823. [PMID: 34191540 PMCID: PMC8684713 DOI: 10.1091/mbc.e21-04-0213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 06/10/2021] [Accepted: 06/25/2021] [Indexed: 11/29/2022] Open
Abstract
Evidence from multiple systems indicates that vesicle SNARE (soluble NSF attachment receptor) proteins are involved in synaptic vesicle endocytosis, although their exact action at the level of single vesicles is unknown. Here we interrogate the role of the main synaptic vesicle SNARE mediating fusion, synaptobrevin-2 (also called VAMP2), in modulation of single synaptic vesicle retrieval. We report that in the absence of synaptobrevin-2, fast and slow modes of single synaptic vesicle retrieval are impaired, indicating a role of the SNARE machinery in coupling exocytosis to endocytosis of single synaptic vesicles. Ultrafast endocytosis was impervious to changes in the levels of synaptobrevin-2, pointing to a separate molecular mechanism underlying this type of recycling. Taken together with earlier studies suggesting a role of synaptobrevin-2 in endocytosis, these results indicate that the machinery for fast synchronous release couples fusion to retrieval and regulates the kinetics of endocytosis in a Ca2+-dependent manner.
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Affiliation(s)
- Natali L. Chanaday
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN 37240-7933
| | - Ege T. Kavalali
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN 37240-7933
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933
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6
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Wan B, Belghazi M, Lemauf S, Poirié M, Gatti JL. Proteomics of purified lamellocytes from Drosophila melanogaster HopT um-l identifies new membrane proteins and networks involved in their functions. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2021; 134:103584. [PMID: 34033897 DOI: 10.1016/j.ibmb.2021.103584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 04/20/2021] [Accepted: 04/22/2021] [Indexed: 06/12/2023]
Abstract
In healthy Drosophila melanogaster larvae, plasmatocytes and crystal cells account for 95% and 5% of the hemocytes, respectively. A third type of hemocytes, lamellocytes, are rare, but their number increases after oviposition by parasitoid wasps. The lamellocytes form successive layers around the parasitoid egg, leading to its encapsulation and melanization, and finally the death of this intruder. However, the total number of lamellocytes per larva remains quite low even after parasitoid infestation, making direct biochemical studies difficult. Here, we used the HopTum-l mutant strain that constitutively produces large numbers of lamellocytes to set up a purification method and analyzed their major proteins by 2D gel electrophoresis and their plasma membrane surface proteins by 1D SDS-PAGE after affinity purification. Mass spectrometry identified 430 proteins from 2D spots and 344 affinity-purified proteins from 1D bands, for a total of 639 unique proteins. Known lamellocyte markers such as PPO3 and the myospheroid integrin were among the components identified with specific chaperone proteins. Affinity purification detected other integrins, as well as a wide range of integrin-associated proteins involved in the formation and function of cell-cell junctions. Overall, the newly identified proteins indicate that these cells are highly adapted to the encapsulation process (recognition, motility, adhesion, signaling), but may also have several other physiological functions (such as secretion and internalization of vesicles) under different signaling pathways. These results provide the basis for further in vivo and in vitro studies of lamellocytes, including the development of new markers to identify coexisting populations and their respective origins and functions in Drosophila immunity.
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Affiliation(s)
- Bin Wan
- Université Côte d'Azur, INRAE, CNRS, Institute Sophia-Agrobiotech, Sophia Antipolis, France
| | - Maya Belghazi
- Institute of NeuroPhysiopathology (INP), UMR7051, CNRS, Aix-Marseille Université, Marseille, 13015, France
| | - Séverine Lemauf
- Université Côte d'Azur, INRAE, CNRS, Institute Sophia-Agrobiotech, Sophia Antipolis, France
| | - Marylène Poirié
- Université Côte d'Azur, INRAE, CNRS, Institute Sophia-Agrobiotech, Sophia Antipolis, France
| | - Jean-Luc Gatti
- Université Côte d'Azur, INRAE, CNRS, Institute Sophia-Agrobiotech, Sophia Antipolis, France.
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7
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Grosso Jasutkar H, Yamamoto A. Do Changes in Synaptic Autophagy Underlie the Cognitive Impairments in Huntington's Disease? J Huntingtons Dis 2021; 10:227-238. [PMID: 33780373 PMCID: PMC8293641 DOI: 10.3233/jhd-200466] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Although Huntington's disease (HD) is classically considered from the perspective of the motor syndrome, the cognitive changes in HD are prominent and often an early manifestation of disease. As such, investigating the underlying pathophysiology of cognitive changes may give insight into important and early neurodegenerative events. In this review, we first discuss evidence from both HD patients and animal models that cognitive changes correlate with early pathological changes at the synapse, an observation that is similarly made in other neurodegenerative conditions that primarily affect cognition. We then describe how autophagy plays a critical role supporting synaptic maintenance in the healthy brain, and how autophagy dysfunction in HD may thereby lead to impaired synaptic maintenance and thus early manifestations of disease.
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Affiliation(s)
| | - Ai Yamamoto
- Department of Neurology, Columbia University, New York, NY, USA.,Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
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8
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Gries M, Christmann A, Schulte S, Weyland M, Rommel S, Martin M, Baller M, Röth R, Schmitteckert S, Unger M, Liu Y, Sommer F, Mühlhaus T, Schroda M, Timmermans JP, Pintelon I, Rappold GA, Britschgi M, Lashuel H, Menger MD, Laschke MW, Niesler B, Schäfer KH. Parkinson mice show functional and molecular changes in the gut long before motoric disease onset. Mol Neurodegener 2021; 16:34. [PMID: 34078425 PMCID: PMC8170976 DOI: 10.1186/s13024-021-00439-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 03/03/2021] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND There is increasing evidence that Parkinson's disease (PD) might start in the gut, thus involving and compromising also the enteric nervous system (ENS). At the clinical onset of the disease the majority of dopaminergic neurons in the midbrain is already destroyed, so that the lack of early biomarkers for the disease represents a major challenge for developing timely treatment interventions. Here, we use a transgenic A30P-α-synuclein-overexpressing PD mouse model to identify appropriate candidate markers in the gut before hallmark symptoms begin to manifest. METHODS Based on a gait analysis and striatal dopamine levels, we defined 2-month-old A30P mice as pre-symptomatic (psA30P), since they are not showing any motoric impairments of the skeletal neuromuscular system and no reduced dopamine levels, but an intestinal α-synuclein pathology. Mice at this particular age were further used to analyze functional and molecular alterations in both, the gastrointestinal tract and the ENS, to identify early pathological changes. We examined the gastrointestinal motility, the molecular composition of the ENS, as well as the expression of regulating miRNAs. Moreover, we applied A30P-α-synuclein challenges in vitro to simulate PD in the ENS. RESULTS A retarded gut motility and early molecular dysregulations were found in the myenteric plexus of psA30P mice. We found that i.e. neurofilament light chain, vesicle-associated membrane protein 2 and calbindin 2, together with the miRNAs that regulate them, are significantly altered in the psA30P, thus representing potential biomarkers for early PD. Many of the dysregulated miRNAs found in the psA30P mice are reported to be changed in PD patients as well, either in blood, cerebrospinal fluid or brain tissue. Interestingly, the in vitro approaches delivered similar changes in the ENS cultures as seen in the transgenic animals, thus confirming the data from the mouse model. CONCLUSIONS These findings provide an interesting and novel approach for the identification of appropriate biomarkers in men.
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Affiliation(s)
- Manuela Gries
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, 66482, Zweibrücken, Germany
| | - Anne Christmann
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, 66482, Zweibrücken, Germany
| | - Steven Schulte
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, 66482, Zweibrücken, Germany
| | - Maximilian Weyland
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, 66482, Zweibrücken, Germany
| | - Stephanie Rommel
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, 66482, Zweibrücken, Germany
| | - Monika Martin
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, 66482, Zweibrücken, Germany
| | - Marko Baller
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, 66482, Zweibrücken, Germany
| | - Ralph Röth
- Department of Human Molecular Genetics, University of Heidelberg, 69120, Heidelberg, Germany
| | - Stefanie Schmitteckert
- Department of Human Molecular Genetics, University of Heidelberg, 69120, Heidelberg, Germany
| | - Marcus Unger
- Department of Neurology, Saarland University, 66421, Homburg, Germany
| | - Yang Liu
- Department of Neurology, Saarland University, 66421, Homburg, Germany
| | - Frederik Sommer
- Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Timo Mühlhaus
- Computational Systems Biology, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Michael Schroda
- Molecular Biotechnology and Systems Biology, University of Kaiserslautern, 67663, Kaiserslautern, Germany
| | - Jean-Pierre Timmermans
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, 2610, Antwerp, Belgium
| | - Isabel Pintelon
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences, University of Antwerp, 2610, Antwerp, Belgium
| | - Gudrun A Rappold
- Department of Human Molecular Genetics, University of Heidelberg, 69120, Heidelberg, Germany
- Interdisciplinary Center of Neuroscience, 69120, Heidelberg, Germany
| | - Markus Britschgi
- Roche Pharma Research and Early Development, Neuroscience and Rare Diseases Discovery and Translational Medicine Area, Neuroscience Discovery, Roche Innovation Center Basel, 4070, Basel, Switzerland
| | - Hilal Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Michael D Menger
- Institute for Clinical & Experimental Surgery, Faculty of Medicine, Saarland University, 66421, Homburg, Germany
| | - Matthias W Laschke
- Institute for Clinical & Experimental Surgery, Faculty of Medicine, Saarland University, 66421, Homburg, Germany
| | - Beate Niesler
- Department of Human Molecular Genetics, University of Heidelberg, 69120, Heidelberg, Germany
| | - Karl-Herbert Schäfer
- Department of Informatics and Microsystems and Technology, University of Applied Science Kaiserslautern, Working Group Enteric Nervous System, 66482, Zweibrücken, Germany.
- Department of Pediatric Surgery, Medical Faculty Mannheim, University of Heidelberg, 68167, Mannheim, Germany.
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9
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Bhimreddy M, Rushton E, Kopke DL, Broadie K. Secreted C-type lectin regulation of neuromuscular junction synaptic vesicle dynamics modulates coordinated movement. J Cell Sci 2021; 134:261954. [PMID: 33973638 DOI: 10.1242/jcs.257592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 04/03/2021] [Indexed: 11/20/2022] Open
Abstract
The synaptic cleft manifests enriched glycosylation, with structured glycans coordinating signaling between presynaptic and postsynaptic cells. Glycosylated signaling ligands orchestrating communication are tightly regulated by secreted glycan-binding lectins. Using the Drosophila neuromuscular junction (NMJ) as a model glutamatergic synapse, we identify a new Ca2+-binding (C-type) lectin, Lectin-galC1 (LGC1), which modulates presynaptic function and neurotransmission strength. We find that LGC1 is enriched in motoneuron presynaptic boutons and secreted into the NMJ extracellular synaptomatrix. We show that LGC1 limits locomotor peristalsis and coordinated movement speed, with a specific requirement for synaptic function, but not NMJ architecture. LGC1 controls neurotransmission strength by limiting presynaptic active zone (AZ) and postsynaptic glutamate receptor (GluR) aligned synapse number, reducing both spontaneous and stimulation-evoked synaptic vesicle (SV) release, and capping SV cycling rate. During high-frequency stimulation (HFS), mutants have faster synaptic depression and impaired recovery while replenishing depleted SV pools. Although LGC1 removal increases the number of glutamatergic synapses, we find that LGC1-null mutants exhibit decreased SV density within presynaptic boutons, particularly SV pools at presynaptic active zones. Thus, LGC1 regulates NMJ neurotransmission to modulate coordinated movement.
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Affiliation(s)
- Meghana Bhimreddy
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Emma Rushton
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Danielle L Kopke
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA.,Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN 37235, USA.,Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
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10
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Role of SNAREs in Neurodegenerative Diseases. Cells 2021; 10:cells10050991. [PMID: 33922505 PMCID: PMC8146804 DOI: 10.3390/cells10050991] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/18/2021] [Accepted: 04/20/2021] [Indexed: 02/06/2023] Open
Abstract
Neurodegenerative diseases are pathologies of the central and peripheral nervous systems characterized by loss of brain functions and problems in movement which occur due to the slow and progressive degeneration of cellular elements. Several neurodegenerative diseases are known such as Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis and many studies on the molecular mechanisms underlying these pathologies have been conducted. Altered functions of some key proteins and the presence of intraneuronal aggregates have been identified as responsible for the development of the diseases. Interestingly, the formation of the SNARE complex has been discovered to be fundamental for vesicle fusion, vesicle recycling and neurotransmitter release. Indeed, inhibition of the formation of the SNARE complex, defects in the SNARE-dependent exocytosis and altered regulation of SNARE-mediated vesicle fusion have been associated with neurodegeneration. In this review, the biological aspects of neurodegenerative diseases and the role of SNARE proteins in relation to the onset of these pathologies are described.
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11
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Andres-Alonso M, Kreutz MR, Karpova A. Autophagy and the endolysosomal system in presynaptic function. Cell Mol Life Sci 2020; 78:2621-2639. [PMID: 33340068 PMCID: PMC8004491 DOI: 10.1007/s00018-020-03722-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 11/17/2020] [Accepted: 11/24/2020] [Indexed: 12/11/2022]
Abstract
The complex morphology of neurons, the specific requirements of synaptic neurotransmission and the accompanying metabolic demands create a unique challenge for proteostasis. The main machineries for neuronal protein synthesis and degradation are localized in the soma, while synaptic junctions are found at vast distances from the cell body. Sophisticated mechanisms must, therefore, ensure efficient delivery of newly synthesized proteins and removal of faulty proteins. These requirements are exacerbated at presynaptic sites, where the demands for protein turnover are especially high due to synaptic vesicle release and recycling that induces protein damage in an intricate molecular machinery, and where replacement of material is hampered by the extreme length of the axon. In this review, we will discuss the contribution of the two major pathways in place, autophagy and the endolysosomal system, to presynaptic protein turnover and presynaptic function. Although clearly different in their biogenesis, both pathways are characterized by cargo collection and transport into distinct membrane-bound organelles that eventually fuse with lysosomes for cargo degradation. We summarize the available evidence with regard to their degradative function, their regulation by presynaptic machinery and the cargo for each pathway. Finally, we will discuss the interplay of both pathways in neurons and very recent findings that suggest non-canonical functions of degradative organelles in synaptic signalling and plasticity.
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Affiliation(s)
- Maria Andres-Alonso
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany
- Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany.
- Leibniz Group 'Dendritic Organelles and Synaptic Function', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, 20251, Hamburg, Germany.
- Center for Behavioral Brain Sciences, Otto Von Guericke University, Magdeburg, Germany.
- German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany.
| | - Anna Karpova
- Research Group Neuroplasticity, Leibniz Institute for Neurobiology, 39118, Magdeburg, Germany.
- Center for Behavioral Brain Sciences, Otto Von Guericke University, Magdeburg, Germany.
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12
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Sun M, Han X, Chang F, Xu H, Colgan L, Liu Y. Regulatory role of sorting nexin 5 in protein stability and vesicular targeting of vesicular acetylcholine transporter to synaptic vesicle-like vesicles in PC12 cells. J Biomed Res 2020; 35:339-350. [PMID: 34230437 PMCID: PMC8502691 DOI: 10.7555/jbr.34.20200095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Accurate targeting of vesicular acetylcholine transporter (VAChT) to synaptic vesicles (SVs) is indispensable for efficient cholinergic transmission. Previous studies have suggested that the dileucine motif within the C-terminus of the transporter is sufficient for its targeting to SVs. However, the cytosolic machinery underlying specific regulation of VAChT trafficking and targeting to SVs is still unclear. Here we used the C-terminus of VAChT as a bait in a yeast two-hybrid screen to identify sorting nexin 5 (SNX5) as its novel interacting protein. SNX5 was detected in the SVs enriched LP2 subcellular fraction of rat brain homogenate and showed strong colocalization with VAChT in both brain sections and PC12 cells. Binding assays suggested that the C-terminal domain of VAChT can interact with both BAR and PX domain of SNX5. Depletion of SNX5 enhanced the degradation of VAChT and the process was mediated through the lysosomal pathway. More importantly, we found that, in PC12 cells, the depletion of SNX5 expression significantly decreased the synaptic vesicle-like vesicles (SVLVs) localization of VAChT. Therefore, the results suggest that SNX5 is a novel regulator for both stability and SV targeting of VAChT.
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Affiliation(s)
- Meihen Sun
- Jiangsu Key Laboratory of Xenotransplantation, and Department of Medical Genetics, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Xu Han
- Jiangsu Key Laboratory of Xenotransplantation, and Department of Medical Genetics, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Fei Chang
- Neuroscience Program, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Hongfei Xu
- Department of Neurology, University of California San Francisco School of Medicine, San Francisco, CA 94143, USA
| | - Lesley Colgan
- Max Planck Florida Institute for Neuroscience, Jupiter, FL 33458, USA. E-mail: lesley.col
| | - Yongjian Liu
- Jiangsu Key Laboratory of Xenotransplantation, and Department of Medical Genetics, Nanjing Medical University, Nanjing, Jiangsu 211166, China. E-mail:
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13
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Alpha-Synuclein and LRRK2 in Synaptic Autophagy: Linking Early Dysfunction to Late-Stage Pathology in Parkinson's Disease. Cells 2020; 9:cells9051115. [PMID: 32365906 PMCID: PMC7290471 DOI: 10.3390/cells9051115] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 12/24/2022] Open
Abstract
The lack of effective disease-modifying strategies is the major unmet clinical need in Parkinson’s disease. Several experimental approaches have attempted to validate cellular targets and processes. Of these, autophagy has received considerable attention in the last 20 years due to its involvement in the clearance of pathologic protein aggregates and maintenance of neuronal homeostasis. However, this strategy mainly addresses a very late stage of the disease, when neuropathology and neurodegeneration have likely “tipped over the edge” and disease modification is extremely difficult. Very recently, autophagy has been demonstrated to modulate synaptic activity, a process distinct from its catabolic function. Abnormalities in synaptic transmission are an early event in neurodegeneration with Leucine-Rich Repeat Kinase 2 (LRRK2) and alpha-synuclein strongly implicated. In this review, we analyzed these processes separately and then discussed the unification of these biomolecular fields with the aim of reconstructing a potential “molecular timeline” of disease onset and progression. We postulate that the elucidation of these pathogenic mechanisms will form a critical basis for the design of novel, effective disease-modifying therapies that could be applied early in the disease process.
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14
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Liu Y, Chu JMT, Yan T, Zhang Y, Chen Y, Chang RCC, Wong GTC. Short-term resistance exercise inhibits neuroinflammation and attenuates neuropathological changes in 3xTg Alzheimer's disease mice. J Neuroinflammation 2020; 17:4. [PMID: 31900170 PMCID: PMC6942350 DOI: 10.1186/s12974-019-1653-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 11/20/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Both human and animal studies have shown beneficial effects of physical exercise on brain health but most tend to be based on aerobic rather than resistance type regimes. Resistance exercise has the advantage of improving both muscular and cardiovascular function, both of which can benefit the frail and the elderly. However, the neuroprotective effects of resistance training in cognitive impairment are not well characterized. METHODS We evaluated whether short-term resistant training could improve cognitive function and pathological changes in mice with pre-existing cognitive impairment. Nine-month-old 3xTg mouse underwent a resistance training protocol of climbing up a 1-m ladder with a progressively heavier weight loading. RESULTS Compared with sedentary counterparts, resistance training improved cognitive performance and reduced neuropathological and neuroinflammatory changes in the frontal cortex and hippocampus of mice. In line with these results, inhibition of pro-inflammatory intracellular pathways was also demonstrated. CONCLUSIONS Short-term resistance training improved cognitive function in 3xTg mice, and conferred beneficial effects on neuroinflammation, amyloid and tau pathology, as well as synaptic plasticity. Resistance training may represent an alternative exercise strategy for delaying disease progression in Alzheimer's disease.
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Affiliation(s)
- Yan Liu
- Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Room K424, Queen Mary Hospital, Pokfulam, Hong Kong, SAR, China.,Laboratory of Neurodegenerative Diseases, LKS Faculty of MedicineSchool of Biomedical Sciences, The University of Hong Kong, Hong Kong, SAR, China
| | - John Man Tak Chu
- Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Room K424, Queen Mary Hospital, Pokfulam, Hong Kong, SAR, China.,Laboratory of Neurodegenerative Diseases, LKS Faculty of MedicineSchool of Biomedical Sciences, The University of Hong Kong, Hong Kong, SAR, China
| | - Tim Yan
- Laboratory of Neurodegenerative Diseases, LKS Faculty of MedicineSchool of Biomedical Sciences, The University of Hong Kong, Hong Kong, SAR, China
| | - Yan Zhang
- Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Room K424, Queen Mary Hospital, Pokfulam, Hong Kong, SAR, China.,Laboratory of Neurodegenerative Diseases, LKS Faculty of MedicineSchool of Biomedical Sciences, The University of Hong Kong, Hong Kong, SAR, China
| | - Ying Chen
- Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Room K424, Queen Mary Hospital, Pokfulam, Hong Kong, SAR, China.,Laboratory of Neurodegenerative Diseases, LKS Faculty of MedicineSchool of Biomedical Sciences, The University of Hong Kong, Hong Kong, SAR, China
| | - Raymond Chuen Chung Chang
- Laboratory of Neurodegenerative Diseases, LKS Faculty of MedicineSchool of Biomedical Sciences, The University of Hong Kong, Hong Kong, SAR, China. .,State Key Laboratory of Brain and Cognitive Sciences, The University of Hong Kong, L4-49, Laboratory Block, Pokfulam, Hong Kong, SAR, China.
| | - Gordon Tin Chun Wong
- Department of Anaesthesiology, LKS Faculty of Medicine, The University of Hong Kong, Room K424, Queen Mary Hospital, Pokfulam, Hong Kong, SAR, China.
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15
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Lee W, Kim SH. Autophagy at synapses in neurodegenerative diseases. Arch Pharm Res 2019; 42:407-415. [DOI: 10.1007/s12272-019-01148-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 03/21/2019] [Indexed: 12/31/2022]
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16
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Şentürk M, Lin G, Zuo Z, Mao D, Watson E, Mikos AG, Bellen HJ. Ubiquilins regulate autophagic flux through mTOR signalling and lysosomal acidification. Nat Cell Biol 2019; 21:384-396. [PMID: 30804504 PMCID: PMC6534127 DOI: 10.1038/s41556-019-0281-x] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 01/14/2019] [Indexed: 12/14/2022]
Abstract
Although the aetiology of amyotrophic lateral sclerosis (ALS) remains poorly understood, impaired proteostasis is a common feature of different forms of ALS. Mutations in genes encoding ubiquilins, UBQLN2 and UBQLN4, cause familial ALS. The role of ubiquilins in proteasomal degradation is well established, but their role in autophagy-lysosomal clearance is poorly defined. Here, we describe a crosstalk between endoplasmic reticulum stress, mTOR signalling and autophagic flux in Drosophila and mammalian cells lacking ubiquilins. We found that loss of ubiquilins leads to endoplasmic reticulum stress, impairs mTORC1 activity, promotes autophagy and causes the demise of neurons. We show that ubiquilin mutants display defective autophagic flux due to reduced lysosome acidification. Ubiquilins are required to maintain proper levels of the V0a/V100 subunit of the vacuolar H+-ATPase and lysosomal pH. Feeding flies acidic nanoparticles alleviates defective autophagic flux in ubiquilin mutants. Hence, our studies reveal a conserved role for ubiquilins as regulators of autophagy by controlling vacuolar H+-ATPase activity and mTOR signalling.
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Affiliation(s)
- Mümine Şentürk
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Guang Lin
- Department of Molecular and Human Genetics, BCM, Houston, TX, USA
| | - Zhongyuan Zuo
- Department of Molecular and Human Genetics, BCM, Houston, TX, USA
| | - Dongxue Mao
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA
| | - Emma Watson
- Department of Bioengineering, Rice University, Houston, TX, USA
- Medical Scientist Training Program, BCM, Houston, TX, USA
| | - Antonios G Mikos
- Department of Bioengineering, Rice University, Houston, TX, USA
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX, USA.
- Department of Molecular and Human Genetics, BCM, Houston, TX, USA.
- Department of Neuroscience, BCM, Houston, TX, USA.
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA.
- Howard Hughes Medical Institute, BCM, Houston, TX, USA.
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17
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Raja SA, Abbas S, Shah STA, Tariq A, Bibi N, Yousuf A, Khawaja A, Nawaz M, Mehmood A, Khan MJ, Hussain A. Increased expression levels of Syntaxin 1A and Synaptobrevin 2/Vesicle-Associated Membrane Protein-2 are associated with the progression of bladder cancer. Genet Mol Biol 2019; 42:40-47. [PMID: 30672978 PMCID: PMC6428126 DOI: 10.1590/1678-4685-gmb-2017-0339] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 07/09/2018] [Indexed: 01/11/2023] Open
Abstract
Gene expression is tightly regulated in time and space through a multitude of
factors consisting of signaling molecules. Soluble
N-ethylmaleimide-sensitive-factor attachment protein receptors (SNARE) are
membrane proteins responsible for the intercellular trafficking of signals
through endocytosis and exocytosis of vesicles. Altered expression of SNARE
proteins in cellular communication is the major hallmark of cancer phenotypes as
indicated in recent studies. SNAREs play an important role in maintaining cell
growth and epithelial membrane permeability of the bladder and are not only
involved in cancer progression but also metastatic cell invasion through
SNARE-mediated trafficking. Synaptobrevin2/Vesicle associated membrane protein-2
(v-SNARE) and Syntaxin (t-SNARE) form a vesicular docking complex during
endocytosis. Some earlier studies have shown a critical role of SNARE in colon,
lungs, and breast cancer progression and metastasis. In this study, we analyzed
the relative expression of the STX1A and VAMP2
(SYB2) for their possible association in the progression
and metastasis of bladder cancer. The profiling of the genes showed a
significant increase in STX1A and VAMP2
expression (p < 0.001) in high-grade tumor cells compared to
normal and low-grade tumors. These findings suggest that elevated expression of
STX1A and VAMP2 might have caused the
abnormal progression and invasion of cancer cells leading to the transformation
of cells into high-grade tumor in bladder cancer.
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Affiliation(s)
- Sadaf Azad Raja
- Department of Biosciences, COMSATS Institute of Information Technology Islamabad, Pakistan
| | - Seher Abbas
- Department of Biosciences, COMSATS Institute of Information Technology Islamabad, Pakistan
| | - Syed Tahir Abbas Shah
- Department of Biosciences, COMSATS Institute of Information Technology Islamabad, Pakistan
| | - Aamira Tariq
- Department of Biosciences, COMSATS Institute of Information Technology Islamabad, Pakistan
| | - Nazia Bibi
- Department of Biosciences, COMSATS Institute of Information Technology Islamabad, Pakistan
| | - Arzu Yousuf
- Department of Urology and Kidney Transplant, Shifa International Hospital, Islamabad, Pakistan
| | - Athar Khawaja
- Department of Urology and Kidney Transplant, Shifa International Hospital, Islamabad, Pakistan
| | - Muhammad Nawaz
- Armed Forces Institute of Urology (AFIU), Rawalpindi, Pakistan
| | - Arshad Mehmood
- Armed Forces Institute of Urology (AFIU), Rawalpindi, Pakistan
| | - Muhammad Jadoon Khan
- Department of Biosciences, COMSATS Institute of Information Technology Islamabad, Pakistan
| | - Alamdar Hussain
- Department of Biosciences, COMSATS Institute of Information Technology Islamabad, Pakistan
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18
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Limanaqi F, Biagioni F, Gambardella S, Ryskalin L, Fornai F. Interdependency Between Autophagy and Synaptic Vesicle Trafficking: Implications for Dopamine Release. Front Mol Neurosci 2018; 11:299. [PMID: 30186112 PMCID: PMC6110820 DOI: 10.3389/fnmol.2018.00299] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/06/2018] [Indexed: 12/16/2022] Open
Abstract
Autophagy (ATG) and the Ubiquitin Proteasome (UP) are the main clearing systems of eukaryotic cells, in that being ultimately involved in degrading damaged and potentially harmful cytoplasmic substrates. Emerging evidence implicates that, in addition to their classic catalytic function in the cytosol, autophagy and the proteasome act as modulators of neurotransmission, inasmuch as they orchestrate degradation and turnover of synaptic vesicles (SVs) and related proteins. These findings are now defining a novel synaptic scenario, where clearing systems and secretory pathways may be considered as a single system, which senses alterations in quality and distribution (in time, amount and place) of both synaptic proteins and neurotransmitters. In line with this, in the present manuscript we focus on evidence showing that, a dysregulation of secretory and trafficking pathways is quite constant in the presence of an impairment of autophagy-lysosomal machinery, which eventually precipitates synaptic dysfunction. Such a dual effect appears not to be just incidental but it rather represents the natural evolution of archaic cell compartments. While discussing these issues, we pose a special emphasis on the role of autophagy upon dopamine (DA) neurotransmission, which is early affected in several neurological and psychiatric disorders. In detail, we discuss how autophagy is engaged not only in removing potentially dangerous proteins, which can interfere with the mechanisms of DA release, but also the fate of synaptic DA vesicles thus surveilling DA neurotransmission. These concepts contribute to shed light on early mechanisms underlying intersection of autophagy with DA-related synaptic disorders.
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Affiliation(s)
- Fiona Limanaqi
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | | | | | - Larisa Ryskalin
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy
| | - Francesco Fornai
- Human Anatomy, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.,IRCCS Neuromed, Pozzilli, Italy
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19
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Zhao H, Wang J, Wang T. The V-ATPase V1 subunit A1 is required for rhodopsin anterograde trafficking in Drosophila. Mol Biol Cell 2018; 29:1640-1651. [PMID: 29742016 PMCID: PMC6080656 DOI: 10.1091/mbc.e17-09-0546] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Synthesis and maturation of the light sensor, rhodopsin, are critical for the maintenance of light sensitivity and for photoreceptor homeostasis. In Drosophila, the main rhodopsin, Rh1, is synthesized in the endoplasmic reticulum and transported to the rhabdomere through the secretory pathway. In an unbiased genetic screen for factors involved in rhodopsin homeostasis, we identified mutations in vha68-1, which encodes the vacuolar proton-translocating ATPase (V-ATPase) catalytic subunit A isoform 1 of the V1 component. Loss of vha68-1 in photoreceptor cells disrupted post-Golgi anterograde trafficking of Rh1, reduced light sensitivity, increased secretory vesicle pH, and resulted in incomplete Rh1 deglycosylation. In addition, vha68-1 was required for activity-independent photoreceptor cell survival. Importantly, vha68-1 mutants exhibited phenotypes similar to those exhibited by mutations in the V0 component of V-ATPase, vha100-1. These data demonstrate that the V1 and V0 components of V-ATPase play key roles in post-Golgi trafficking of Rh1 and that Drosophila may represent an important animal model system for studying diseases associated with V-ATPase dysfunction.
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Affiliation(s)
- Haifang Zhao
- School of Life Sciences, Tsinghua University, Beijing 100084, China.,National Institute of Biological Sciences, Beijing 102206, China
| | - Jing Wang
- National Institute of Biological Sciences, Beijing 102206, China
| | - Tao Wang
- National Institute of Biological Sciences, Beijing 102206, China
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20
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Jin EJ, Kiral FR, Ozel MN, Burchardt LS, Osterland M, Epstein D, Wolfenberg H, Prohaska S, Hiesinger PR. Live Observation of Two Parallel Membrane Degradation Pathways at Axon Terminals. Curr Biol 2018; 28:1027-1038.e4. [PMID: 29551411 PMCID: PMC5944365 DOI: 10.1016/j.cub.2018.02.032] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 01/24/2018] [Accepted: 02/14/2018] [Indexed: 01/04/2023]
Abstract
Neurons are highly polarized cells that require continuous turnover of membrane proteins at axon terminals to develop, function, and survive. Yet, it is still unclear whether membrane protein degradation requires transport back to the cell body or whether degradation also occurs locally at the axon terminal, where live observation of sorting and degradation has remained a challenge. Here, we report direct observation of two cargo-specific membrane protein degradation mechanisms at axon terminals based on a live-imaging approach in intact Drosophila brains. We show that different acidification-sensing cargo probes are sorted into distinct classes of degradative “hub” compartments for synaptic vesicle proteins and plasma membrane proteins at axon terminals. Sorting and degradation of the two cargoes in the separate hubs are molecularly distinct. Local sorting of synaptic vesicle proteins for degradation at the axon terminal is, surprisingly, Rab7 independent, whereas sorting of plasma membrane proteins is Rab7 dependent. The cathepsin-like protease CP1 is specific to synaptic vesicle hubs, and its delivery requires the vesicle SNARE neuronal synaptobrevin. Cargo separation only occurs at the axon terminal, whereas degradative compartments at the cell body are mixed. These data show that at least two local, molecularly distinct pathways sort membrane cargo for degradation specifically at the axon terminal, whereas degradation can occur both at the terminal and en route to the cell body.
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Affiliation(s)
- Eugene Jennifer Jin
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany; Graduate School of Biomedical Sciences, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Ferdi Ridvan Kiral
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany
| | - Mehmet Neset Ozel
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany; Graduate School of Biomedical Sciences, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | - Lara Sophie Burchardt
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany
| | - Marc Osterland
- Zuse Institute Berlin, Takustraße 7, 14195 Berlin, Germany
| | - Daniel Epstein
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany
| | - Heike Wolfenberg
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany
| | | | - Peter Robin Hiesinger
- Division of Neurobiology, Freie Universität Berlin, Königin Luise Straße 1-3, 14195 Berlin, Germany.
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21
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Jin EJ, Kiral FR, Hiesinger PR. The where, what, and when of membrane protein degradation in neurons. Dev Neurobiol 2018; 78:283-297. [PMID: 28884504 PMCID: PMC5816708 DOI: 10.1002/dneu.22534] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/01/2017] [Accepted: 09/04/2017] [Indexed: 12/20/2022]
Abstract
Membrane protein turnover and degradation are required for the function and health of all cells. Neurons may live for the entire lifetime of an organism and are highly polarized cells with spatially segregated axonal and dendritic compartments. Both longevity and morphological complexity represent challenges for regulated membrane protein degradation. To investigate how neurons cope with these challenges, an increasing number of recent studies investigated local, cargo-specific protein sorting, and degradation at axon terminals and in dendritic processes. In this review, we explore the current answers to the ensuing questions of where, what, and when membrane proteins are degraded in neurons. © 2017 The Authors Developmental Neurobiology Published by Wiley Periodicals, Inc. Develop Neurobiol 78: 283-297, 2018.
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Affiliation(s)
- Eugene Jennifer Jin
- Division of NeurobiologyInstitute for Biology, Freie Universität Berlin14195 BerlinGermany
- Graduate School of Biomedical SciencesUniversity of Texas Southwestern Medical CenterDallasTX75390USA
| | - Ferdi Ridvan Kiral
- Division of NeurobiologyInstitute for Biology, Freie Universität Berlin14195 BerlinGermany
| | - Peter Robin Hiesinger
- Division of NeurobiologyInstitute for Biology, Freie Universität Berlin14195 BerlinGermany
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22
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Gupta VK, Pech U, Bhukel A, Fulterer A, Ender A, Mauermann SF, Andlauer TFM, Antwi-Adjei E, Beuschel C, Thriene K, Maglione M, Quentin C, Bushow R, Schwärzel M, Mielke T, Madeo F, Dengjel J, Fiala A, Sigrist SJ. Spermidine Suppresses Age-Associated Memory Impairment by Preventing Adverse Increase of Presynaptic Active Zone Size and Release. PLoS Biol 2016; 14:e1002563. [PMID: 27684064 PMCID: PMC5042543 DOI: 10.1371/journal.pbio.1002563] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2016] [Accepted: 08/26/2016] [Indexed: 01/24/2023] Open
Abstract
Memories are assumed to be formed by sets of synapses changing their structural or functional performance. The efficacy of forming new memories declines with advancing age, but the synaptic changes underlying age-induced memory impairment remain poorly understood. Recently, we found spermidine feeding to specifically suppress age-dependent impairments in forming olfactory memories, providing a mean to search for synaptic changes involved in age-dependent memory impairment. Here, we show that a specific synaptic compartment, the presynaptic active zone (AZ), increases the size of its ultrastructural elaboration and releases significantly more synaptic vesicles with advancing age. These age-induced AZ changes, however, were fully suppressed by spermidine feeding. A genetically enforced enlargement of AZ scaffolds (four gene-copies of BRP) impaired memory formation in young animals. Thus, in the Drosophila nervous system, aging AZs seem to steer towards the upper limit of their operational range, limiting synaptic plasticity and contributing to impairment of memory formation. Spermidine feeding suppresses age-dependent memory impairment by counteracting these age-dependent changes directly at the synapse.
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Affiliation(s)
- Varun K. Gupta
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Ulrike Pech
- Georg-August-Universität Göttingen, Molecular Neurobiology of Behavior, Göttingen, Germany
| | - Anuradha Bhukel
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Andreas Fulterer
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Anatoli Ender
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Stephan F. Mauermann
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | | | | | - Christine Beuschel
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Kerstin Thriene
- Centre for Systems Biological Analysis, University of Freiburg, Freiburg, Germany
| | - Marta Maglione
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - Christine Quentin
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
| | - René Bushow
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Martin Schwärzel
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
| | - Thorsten Mielke
- Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Frank Madeo
- Institute for Molecular Biosciences, NAWI Graz, University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Joern Dengjel
- Centre for Systems Biological Analysis, University of Freiburg, Freiburg, Germany
| | - André Fiala
- Georg-August-Universität Göttingen, Molecular Neurobiology of Behavior, Göttingen, Germany
| | - Stephan J. Sigrist
- Institute for Biology/Genetics, Freie Universität Berlin, Berlin, Germany
- NeuroCure, Charité, Berlin, Germany
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Chen L, Zhang YH, Zheng M, Huang T, Cai YD. Identification of compound-protein interactions through the analysis of gene ontology, KEGG enrichment for proteins and molecular fragments of compounds. Mol Genet Genomics 2016; 291:2065-2079. [PMID: 27530612 DOI: 10.1007/s00438-016-1240-x] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 08/09/2016] [Indexed: 12/13/2022]
Abstract
Compound-protein interactions play important roles in every cell via the recognition and regulation of specific functional proteins. The correct identification of compound-protein interactions can lead to a good comprehension of this complicated system and provide useful input for the investigation of various attributes of compounds and proteins. In this study, we attempted to understand this system by extracting properties from both proteins and compounds, in which proteins were represented by gene ontology and KEGG pathway enrichment scores and compounds were represented by molecular fragments. Advanced feature selection methods, including minimum redundancy maximum relevance, incremental feature selection, and the basic machine learning algorithm random forest, were used to analyze these properties and extract core factors for the determination of actual compound-protein interactions. Compound-protein interactions reported in The Binding Databases were used as positive samples. To improve the reliability of the results, the analytic procedure was executed five times using different negative samples. Simultaneously, five optimal prediction methods based on a random forest and yielding maximum MCCs of approximately 77.55 % were constructed and may be useful tools for the prediction of compound-protein interactions. This work provides new clues to understanding the system of compound-protein interactions by analyzing extracted core features. Our results indicate that compound-protein interactions are related to biological processes involving immune, developmental and hormone-associated pathways.
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Affiliation(s)
- Lei Chen
- College of Information Engineering, Shanghai Maritime University, Shanghai, 201306, People's Republic of China.
| | - Yu-Hang Zhang
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, People's Republic of China
| | - Mingyue Zheng
- Drug Discovery and Design Center, Shanghai Institute of Materia Medica, Shanghai, 201203, People's Republic of China
| | - Tao Huang
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, 200031, People's Republic of China
| | - Yu-Dong Cai
- School of Life Sciences, Shanghai University, Shanghai, 200444, People's Republic of China.
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Ubiquitin-Synaptobrevin Fusion Protein Causes Degeneration of Presynaptic Motor Terminals in Mice. J Neurosci 2015; 35:11514-31. [PMID: 26290230 DOI: 10.1523/jneurosci.5288-14.2015] [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] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Protein aggregates containing ubiquitin (Ub) are commonly observed in neurodegenerative disorders, implicating the involvement of the ubiquitin proteasome system (UPS) in their pathogenesis. Here, we aimed to generate a mouse model for monitoring UPS function using a green fluorescent protein (GFP)-based substrate that carries a "noncleavable" N-terminal ubiquitin moiety (Ub(G76V)). We engineered transgenic mice expressing a fusion protein, consisting of the following: (1) Ub(G76V), GFP, and a synaptic vesicle protein synaptobrevin-2 (Ub(G76V)-GFP-Syb2); (2) GFP-Syb2; or (3) Ub(G76V)-GFP-Syntaxin1, all under the control of a neuron-specific Thy-1 promoter. As expected, Ub(G76V)-GFP-Syb2, GFP-Syb2, and Ub(G76V)-GFP-Sytaxin1 were highly expressed in neurons, such as motoneurons and motor nerve terminals of the neuromuscular junction (NMJ). Surprisingly, Ub(G76V)-GFP-Syb2 mice developed progressive adult-onset degeneration of motor nerve terminals, whereas GFP-Syb2 and Ub(G76V)-GFP-Syntaxin1 mice were normal. The degeneration of nerve terminals in Ub(G76V)-GFP-Syb2 mice was preceded by a progressive impairment of synaptic transmission at the NMJs. Biochemical analyses demonstrated that Ub(G76V)-GFP-Syb2 interacted with SNAP-25 and Syntaxin1, the SNARE partners of synaptobrevin. Ultrastructural analyses revealed a marked reduction in synaptic vesicle density, accompanying an accumulation of tubulovesicular structures at presynaptic nerve terminals. These morphological defects were largely restricted to motor nerve terminals, as the ultrastructure of motoneuron somata appeared to be normal at the stages when synaptic nerve terminals degenerated. Furthermore, synaptic vesicle endocytosis and membrane trafficking were impaired in Ub(G76V)-GFP-Syb2 mice. These findings indicate that Ub(G76V)-GFP-Syb2 may compete with endogenous synaptobrevin, acting as a gain-of-function mutation that impedes SNARE function, resulting in the depletion of synaptic vesicles and degeneration of the nerve terminals. SIGNIFICANCE STATEMENT Degeneration of motor nerve terminals occurs in amyotrophic lateral sclerosis (ALS) patients as well as in mouse models of ALS, leading to progressive paralysis. What causes a motor nerve terminal to degenerate remains unknown. Here we report on transgenic mice expressing a ubiquitinated synaptic vesicle protein (Ub(G76V)-GFP-Syb2) that develop progressive degeneration of motor nerve terminals. These mice may serve as a model for further elucidating the underlying cellular and molecular mechanisms of presynaptic nerve terminal degeneration.
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25
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Villar-Piqué A, Lopes da Fonseca T, Outeiro TF. Structure, function and toxicity of alpha-synuclein: the Bermuda triangle in synucleinopathies. J Neurochem 2015; 139 Suppl 1:240-255. [PMID: 26190401 DOI: 10.1111/jnc.13249] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 06/29/2015] [Accepted: 07/14/2015] [Indexed: 12/11/2022]
Abstract
Parkinson's disease belongs to a group of currently incurable neurodegenerative disorders characterized by the misfolding and accumulation of alpha-synuclein aggregates that are commonly known as synucleinopathies. Clinically, synucleinopathies are heterogeneous, reflecting the somewhat selective neuronal vulnerability characteristic of each disease. The precise molecular underpinnings of synucleinopathies remain unclear, but the process of aggregation of alpha-synuclein appears as a central event. However, there is still no consensus with respect to the toxic forms of alpha-synuclein, hampering our ability to use the protein as a target for therapeutic intervention. To decipher the molecular bases of synucleinopathies, it is essential to understand the complex triangle formed between the structure, function and toxicity of alpha-synuclein. Recently, important steps have been undertaken to elucidate the role of the protein in both physiological and pathological conditions. Here, we provide an overview of recent findings in the field of alpha-synuclein research, and put forward a new perspective over paradigms that persist in the field. Establishing whether alpha-synuclein has a causative role in all synucleinopathies will enable the identification of targets for the development of novel therapeutic strategies for this devastating group of disorders. Alpha-synuclein is the speculated cornerstone of several neurodegenerative disorders known as Synucleinopathies. Nevertheless, the mechanisms underlying the pathogenic effects of this protein remain unknown. Here, we review the recent findings in the three corners of alpha-synuclein biology - structure, function and toxicity - and discuss the enigmatic roads that have accompanied alpha-synuclein from the beginning. This article is part of a special issue on Parkinson disease.
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Affiliation(s)
- Anna Villar-Piqué
- Department of NeuroDegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany
| | - Tomás Lopes da Fonseca
- Department of NeuroDegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany.,Instituto de Fisiologia, Faculty of Medicine, University of Lisbon, Lisboa, Portugal
| | - Tiago Fleming Outeiro
- Department of NeuroDegeneration and Restorative Research, Center for Nanoscale Microscopy and Molecular Physiology of the Brain, University Medical Center Göttingen, Göttingen, Germany. .,Instituto de Fisiologia, Faculty of Medicine, University of Lisbon, Lisboa, Portugal. .,CEDOC, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal.
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26
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Shen DN, Zhang LH, Wei EQ, Yang Y. Autophagy in synaptic development, function, and pathology. Neurosci Bull 2015; 31:416-26. [PMID: 26139541 DOI: 10.1007/s12264-015-1536-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 05/30/2015] [Indexed: 01/04/2023] Open
Abstract
In the nervous system, neurons contact each other to form neuronal circuits and drive behavior, relying heavily on synaptic connections. The proper development and growth of synapses allows functional transmission of electrical information between neurons or between neurons and muscle fibers. Defects in synapse-formation or development lead to many diseases. Autophagy, a major determinant of protein turnover, is an essential process that takes place in developing synapses. During the induction of autophagy, proteins and cytoplasmic components are encapsulated in autophagosomes, which fuse with lysosomes to form autolysosomes. The cargoes are subsequently degraded and recycled. However, aberrant autophagic activity may lead to synaptic dysfunction, which is a common pathological characteristic in several disorders. Here, we review the current understanding of autophagy in regulating synaptic development and function. In addition, autophagy-related synaptic dysfunction in human diseases is also summarized.
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Affiliation(s)
- Dan-Na Shen
- Department of Pharmacology, Hangzhou Key Laboratory of Medical Neurobiology, School of Medicine, Hangzhou Normal University, Hangzhou, 310036, China
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27
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A neuroprotective function of NSF1 sustains autophagy and lysosomal trafficking in Drosophila. Genetics 2014; 199:511-22. [PMID: 25519897 DOI: 10.1534/genetics.114.172403] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
A common feature of many neurodegenerative diseases is the accumulation of toxic proteins that disrupt vital cellular functions. Degradative pathways such as autophagy play an important protective role in breaking down misfolded and long-lived proteins. Neurons are particularly vulnerable to defects in these pathways, but many of the details regarding the link between autophagy and neurodegeneration remain unclear. We previously found that temperature-sensitive paralytic mutants in Drosophila are enriched for those exhibiting age-dependent neurodegeneration. Here we show that one of these mutants, comatose (comt), in addition to locomotor defects, displays shortened lifespan and progressive neurodegeneration, including loss of dopaminerigic (DA) neurons. comt encodes N-ethyl-maleimide sensitive fusion protein (NSF1), which has a well-documented role in synaptic transmission. However, the neurodegenerative phenotypes we observe in comt mutants do not appear to depend on defects in synaptic transmission, but rather from their inability to sustain autophagy under stress, due at least in part to a defect in trafficking of lysosomal proteases such as cathepsin-L. Conversely, overexpression of NSF1 rescues α-synuclein-induced toxicity of DA neurons in a model of Parkinson's disease. Our results demonstrate a neuroprotective role for NSF1 that involves mediation of fusion events crucial for degradative pathways such as autophagy, providing greater understanding of cellular dysfunctions common to several neurodegenerative diseases.
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Kosiorek M, Zylinska L, Zablocki K, Pikula S. Calcineurin/NFAT signaling represses genes Vamp1 and Vamp2 via PMCA-dependent mechanism during dopamine secretion by Pheochromocytoma cells. PLoS One 2014; 9:e92176. [PMID: 24667359 PMCID: PMC3965406 DOI: 10.1371/journal.pone.0092176] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 02/19/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Plasma membrane Ca(2+)-ATPases (PMCA) extrude Ca(2+) ions out of the cell and contribute to generation of calcium oscillations. Calcium signaling is crucial for transcriptional regulation of dopamine secretion by neuroendocrine PC12 cells. Low resting [Ca(2+)]c in PC12 cells is maintained mainly by two Ca(2+)-ATPases, PMCA2 and PMCA3. Recently, we found that Ca(2+) dependent phosphatase calcineurin was excessively activated under conditions of experimental downregulation of PMCA2 or PMCA3. Thus, the aim of this study was to explain if, via modulation of the Ca(2+)/calcineurin-dependent nuclear factor of activated T cells (NFAT) pathway, PMCA2 and PMCA3 affect intracellular signaling in pheochromocytoma/neuronal cells/PC12 cells. Secondly, we tested whether this might influence dopamine secretion by PC12 cells. RESULTS PMCA2- and PMCA3-deficient cells displayed profound decrease in dopamine secretion accompanied by a permanent increase in [Ca(2+)]c. Reduction in secretion might result from changes in NFAT signaling, following altered PMCA pattern. Consequently, activation of NFAT1 and NFAT3 transcription factors was observed in PMCA2- or PMCA3-deficient cells. Furthermore, chromatin immunoprecipitation assay indicated that NFATs could be involved in repression of Vamp genes encoding vesicle associated membrane proteins (VAMP). CONCLUSIONS PMCA2 and PMCA3 are crucial for dopamine secretion in PC12 cells. Reduction in PMCA2 or PMCA3 led to calcium-dependent activation of calcineurin/NFAT signaling and, in consequence, to repression of the Vamp gene and deterioration of the SNARE complex formation in PC12 cells.
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Affiliation(s)
- Michalina Kosiorek
- Department of Biochemistry, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
- Laboratory of Neurogenetics, Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre PAS, Warsaw, Poland
- * E-mail: (MK); (SP)
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University, Lodz, Poland
| | - Krzysztof Zablocki
- Department of Biochemistry, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
| | - Slawomir Pikula
- Department of Biochemistry, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
- * E-mail: (MK); (SP)
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29
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Cherry S, Jin EJ, Ozel MN, Lu Z, Agi E, Wang D, Jung WH, Epstein D, Meinertzhagen IA, Chan CC, Hiesinger PR. Charcot-Marie-Tooth 2B mutations in rab7 cause dosage-dependent neurodegeneration due to partial loss of function. eLife 2013; 2:e01064. [PMID: 24327558 PMCID: PMC3857549 DOI: 10.7554/elife.01064] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The small GTPase Rab7 is a key regulator of endosomal maturation in eukaryotic cells. Mutations in rab7 are thought to cause the dominant neuropathy Charcot-Marie-Tooth 2B (CMT2B) by a gain-of-function mechanism. Here we show that loss of rab7, but not overexpression of rab7 CMT2B mutants, causes adult-onset neurodegeneration in a Drosophila model. All CMT2B mutant proteins retain 10–50% function based on quantitative imaging, electrophysiology, and rescue experiments in sensory and motor neurons in vivo. Consequently, expression of CMT2B mutants at levels between 0.5 and 10-fold their endogenous levels fully rescues the neuropathy-like phenotypes of the rab7 mutant. Live imaging reveals that CMT2B proteins are inefficiently recruited to endosomes, but do not impair endosomal maturation. These findings are not consistent with a gain-of-function mechanism. Instead, they indicate a dosage-dependent sensitivity of neurons to rab7-dependent degradation. Our results suggest a therapeutic approach opposite to the currently proposed reduction of mutant protein function. DOI:http://dx.doi.org/10.7554/eLife.01064.001 Charcot-Marie-Tooth disease is an inherited disorder of the nervous system with symptoms that typically begin in adolescence or early adulthood. The sensory and motor nerves gradually degenerate, causing muscles to waste away and leading to the loss of touch sensation across the body. One subtype of the disease—Charcot-Marie-Tooth 2B—is caused by mutations in a gene called rab7, which codes for a protein that helps to regulate the breakdown of waste proteins inside cells. Charcot-Marie-Tooth 2B is described as a genetically dominant disorder because all patients have one wild type copy and one mutant copy of the rab7 gene. Overexpression of the mutant gene in cells grown in culture alters many of the signaling pathways inside the cells, but it is unclear whether these alterations cause the pathology seen in the disease. Now, Cherry et al. have obtained new insights into the genetics of Charcot-Marie-Tooth 2B by creating the first animal model of the disorder. Fruit flies that did not have the rab7 gene in the light-sensitive sensory neurons in their eyes were used to compare normal and mutant cells. While the two cell types were initially similar, the mutant cells gradually degenerated in the adult animal. By contrast, cells that overexpressed a mutant form of the rab7 gene continued to function normally throughout adulthood. Moreover, when mutant Rab7 proteins were introduced into the cells that lacked the rab7 gene, the proteins restored the cells’ sensitivity to light. These results suggest that mutant Rab7 proteins do not cause degeneration; instead, it is the loss of normal Rab7 function that causes problems. At present, most research into treatment is aimed at finding ways to reduce the activity of mutant Rab7 proteins. However, the work of Cherry et al. suggests that increasing the activity of normal Rab7 proteins—or increasing the activity of alternative pathways that degrade waste proteins—may help to restore nerve function in this, and possibly other, neurodegenerative diseases. DOI:http://dx.doi.org/10.7554/eLife.01064.002
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Affiliation(s)
- Smita Cherry
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, United States
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30
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Abstract
Recent evidence suggests that endocytosis, not exocytosis, can be rate limiting for neurotransmitter release at excitatory CNS synapses during sustained activity and therefore may be a principal determinant of synaptic fatigue. At low stimulation frequencies, the probability of synaptic release is linked to the probability of synaptic retrieval such that evoked release results in proportional retrieval even for release of single synaptic vesicles. The exact mechanism by which the retrieval rates are coupled to release rates, known as compensatory endocytosis, remains unknown. Here we show that inactivation of presynaptic myosin II (MII) decreases the probability of synaptic retrieval. To be able to differentiate between the presynaptic and postsynaptic functions of MII, we developed a live cell substrate patterning technique to create defined neural circuits composed of small numbers of embryonic mouse hippocampal neurons and physically isolated from the surrounding culture. Acute application of blebbistatin to inactivate MII in circuits strongly inhibited evoked release but not spontaneous release. In circuits incorporating both control and MIIB knock-out cells, loss of presynaptic MIIB function correlated with a large decrease in the amplitude of evoked release. Using activity-dependent markers FM1-43 and horseradish peroxidase, we found that MII inactivation greatly slowed vesicular replenishment of the recycling pool but did not impede synaptic release. These results indicate that MII-driven tension or actin dynamics regulate the major pathway for synaptic vesicle retrieval. Changes in retrieval rates determine the size of the recycling pool. The resulting effect on release rates, in turn, brings about changes in synaptic strength.
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31
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Xiong B, Bellen HJ. Rhodopsin homeostasis and retinal degeneration: lessons from the fly. Trends Neurosci 2013; 36:652-60. [PMID: 24012059 DOI: 10.1016/j.tins.2013.08.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 08/02/2013] [Accepted: 08/12/2013] [Indexed: 11/16/2022]
Abstract
Rhodopsins (Rh) are G protein-coupled receptors that function as light-sensors in photoreceptors. In humans, Rh mutations cause retinitis pigmentosa (RP), a degenerative disease that ultimately results in blindness. Studies in Drosophila have provided many insights into basic Rh biology and have identified pathways that lead to retinal degeneration. It has been shown that, because Rh is very abundant in photoreceptors, its accumulation in numerous organelles induces severe stress and results in degeneration of these cells. Moreover, genetic lesions that affect proper activation of membrane-bound Rh lead to disruption in Ca(2+) homeostasis which also causes photoreceptor degeneration. We review here the molecular signals involved in Rh homeostasis and the mechanisms underlying retinal degeneration in flies, and discuss possible links to human diseases.
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Affiliation(s)
- Bo Xiong
- Program in Developmental Biology, Baylor College of Medicine, Houston, Texas 77030, USA
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32
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The synaptic maintenance problem: membrane recycling, Ca2+ homeostasis and late onset degeneration. Mol Neurodegener 2013; 8:23. [PMID: 23829673 PMCID: PMC3708831 DOI: 10.1186/1750-1326-8-23] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 07/05/2013] [Indexed: 01/02/2023] Open
Abstract
Most neurons are born with the potential to live for the entire lifespan of the organism. In addition, neurons are highly polarized cells with often long axons, extensively branched dendritic trees and many synaptic contacts. Longevity together with morphological complexity results in a formidable challenge to maintain synapses healthy and functional. This challenge is often evoked to explain adult-onset degeneration in numerous neurodegenerative disorders that result from otherwise divergent causes. However, comparably little is known about the basic cell biological mechanisms that keep normal synapses alive and functional in the first place. How the basic maintenance mechanisms are related to slow adult-onset degeneration in different diseasesis largely unclear. In this review we focus on two basic and interconnected cell biological mechanisms that are required for synaptic maintenance: endomembrane recycling and calcium (Ca2+) homeostasis. We propose that subtle defects in these homeostatic processes can lead to late onset synaptic degeneration. Moreover, the same basic mechanisms are hijacked, impaired or overstimulated in numerous neurodegenerative disorders. Understanding the pathogenesis of these disorders requires an understanding of both the initial cause of the disease and the on-going changes in basic maintenance mechanisms. Here we discuss the mechanisms that keep synapses functional over long periods of time with the emphasis on their role in slow adult-onset neurodegeneration.
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33
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Yang Y, Coleman M, Zhang L, Zheng X, Yue Z. Autophagy in axonal and dendritic degeneration. Trends Neurosci 2013; 36:418-28. [PMID: 23639383 DOI: 10.1016/j.tins.2013.04.001] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 04/01/2013] [Accepted: 04/01/2013] [Indexed: 12/19/2022]
Abstract
Degeneration of axons and dendrites is a common and early pathological feature of many neurodegenerative disorders, and is thought to be regulated by mechanisms distinct from those determining death of the cell body. The unique structures of axons and dendrites (collectively neurites) may cause them to be particularly vulnerable to the accumulation of protein aggregates and damaged organelles. Autophagy is a catabolic mechanism in which cells clear protein aggregates and damaged organelles. Basal autophagy occurs continuously as a housekeeping function, and can be acutely expanded in response to stress or injury. Emerging evidence shows that insufficient or excessive autophagy contributes to neuritic degeneration. Here, we review the recent progress that has begun to reveal the role of autophagy in neurite function and degeneration.
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Affiliation(s)
- Yi Yang
- Department of Pharmacology, Hangzhou Key Laboratory of Medical Neurobiology, School of Medicine, Hangzhou Normal University, Hangzhou 310036, PR China.
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34
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Elfrink HL, Zwart R, Baas F, Scheper W. Inhibition of endoplasmic reticulum associated degradation reduces endoplasmic reticulum stress and alters lysosomal morphology and distribution. Mol Cells 2013; 35:291-7. [PMID: 23515578 PMCID: PMC3887885 DOI: 10.1007/s10059-013-2286-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 02/06/2013] [Accepted: 02/13/2013] [Indexed: 12/11/2022] Open
Abstract
Disturbances in proteostasis are observed in many neurodegenerative diseases. This leads to activation of protein quality control to restore proteostasis, with a key role for the removal of aberrant proteins by proteolysis. The unfolded protein response (UPR) is a protein quality control mechanism of the endoplasmic reticulum (ER) that is activated in several neurodegenerative diseases. Recently we showed that the major proteolytic pathway during UPR activation is via the autophagy/lysosomal system. Here we investigate UPR induction if the other major proteolytic pathway of the ER -ER associated degradation (ERAD)-is inhibited. Surprisingly, impairment of ERAD results in decreased UPR activation and protects against ER stress toxicity. Autophagy induction is not affected under these conditions, however, a striking relocalization of the lysosomes is observed. Our data suggest that a protective UPR-modulating mechanism is activated if ERAD is inhibited, which involves lysosomes. Our data provide insight in the cross-talk between proteolytic pathways involved in ER proteostasis. This has implications for neurodegenerative diseases like Alzheimer's disease where disturbed ER proteostasis and proteolytic impairment are early phenomena in the pathology.
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Affiliation(s)
- Hyung Lim Elfrink
- Department of Genome Analysis, Academic Medical Center, Amsterdam,
the Netherlands
| | - Rob Zwart
- Department of Genome Analysis, Academic Medical Center, Amsterdam,
the Netherlands
| | - Frank Baas
- Department of Genome Analysis, Academic Medical Center, Amsterdam,
the Netherlands
- Department of Neurology, Academic Medical Center, Amsterdam,
the Netherlands
| | - Wiep Scheper
- Department of Genome Analysis, Academic Medical Center, Amsterdam,
the Netherlands
- Department of Neurology, Academic Medical Center, Amsterdam,
the Netherlands
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35
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Membrane trafficking in neuronal maintenance and degeneration. Cell Mol Life Sci 2012; 70:2919-34. [PMID: 23132096 PMCID: PMC3722462 DOI: 10.1007/s00018-012-1201-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Revised: 10/13/2012] [Accepted: 10/15/2012] [Indexed: 10/28/2022]
Abstract
Defects in membrane trafficking and degradation are hallmarks of most, and maybe all, neurodegenerative disorders. Such defects typically result in the accumulation of undegraded proteins due to aberrant endosomal sorting, lysosomal degradation, or autophagy. The genetic or environmental cause of a specific disease may directly affect these membrane trafficking processes. Alternatively, changes in intracellular sorting and degradation can occur as cellular responses of degenerating neurons to unrelated primary defects such as insoluble protein aggregates or other neurotoxic insults. Importantly, altered membrane trafficking may contribute to the pathogenesis or indeed protect the neuron. The observation of dramatic changes to membrane trafficking thus comes with the challenging need to distinguish pathological from protective alterations. Here, we will review our current knowledge about the protective and destructive roles of membrane trafficking in neuronal maintenance and degeneration. In particular, we will first focus on the question of what type of membrane trafficking keeps healthy neurons alive in the first place. Next, we will discuss what alterations of membrane trafficking are known to occur in Alzheimer's disease and other tauopathies, Parkinson's disease, polyQ diseases, peripheral neuropathies, and lysosomal storage disorders. Combining the maintenance and degeneration viewpoints may yield insight into how to distinguish when membrane trafficking functions protectively or contributes to degeneration.
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36
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Mejia J, Haberman A. Neuronal synaptobrevin promotes longevity in Drosophila photoreceptors. Commun Integr Biol 2012; 5:620-2. [PMID: 23740166 PMCID: PMC3541331 DOI: 10.4161/cib.21434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Neurons have unique challenges relative to other cell types. Unlike most other cells, neurons must remain healthy and functional throughout the lifespan of an animal. Premature neuronal loss underlies many age-related neurodegenerative diseases, including Alzheimer and Parkinson Diseases. Despite previous research aimed at understanding the mechanisms of age-related neurodegenerative diseases, little is known about the mechanisms that allow neurons to remain functional for the lifetime of a healthy animal. Understanding these cellular and biochemical processes is essential to promote healthful aging and reduce the severity of neurodegenerative disease. Here we discuss our recent identification of neuron-specific proteins that regulate endosome fusion events and the role of endosomes in maintaining healthy neurons.
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Affiliation(s)
- Jonathan Mejia
- Neuroscience Department; Oberlin College; Oberlin, OH USA
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37
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Mitch L. n-Syb makes a dangerous delivery. J Biophys Biochem Cytol 2012. [PMCID: PMC3265947 DOI: 10.1083/jcb.1962iti2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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