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Das S, van Engelen MPE, Goossens J, Jacobs D, Bongers B, Fieldhouse JLP, Pijnenburg YAL, Teunissen CE, Vanmechelen E, Verberk IMW. The use of synaptic biomarkers in cerebrospinal fluid to differentiate behavioral variant of frontotemporal dementia from primary psychiatric disorders and Alzheimer's disease. Alzheimers Res Ther 2024; 16:34. [PMID: 38355535 PMCID: PMC10865562 DOI: 10.1186/s13195-024-01409-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/04/2024] [Indexed: 02/16/2024]
Abstract
BACKGROUND Lack of early molecular biomarkers in sporadic behavioral variants of frontotemporal dementia (bvFTD) and its clinical overlap with primary psychiatric disorders (PPD) hampers its diagnostic distinction. Synaptic dysfunction is an early feature in bvFTD and identification of specific biomarkers might improve its diagnostic accuracy. Our goal was to understand the differential diagnostic potential of cerebrospinal fluid (CSF) synaptic biomarkers in bvFTD versus PPD and their specificity towards bvFTD compared with Alzheimer's disease (AD) and controls. Additionally, we explored the association of CSF synaptic biomarkers with social cognition, cognitive performance, and disease severity in these clinical groups. METHODS Participants with probable bvFTD (n = 57), PPD (n = 71), AD (n = 60), and cognitively normal controls (n = 39) with available CSF, cognitive tests, and disease severity as frontotemporal lobar degeneration-modified clinical dementia rating scale (FTLD-CDR) were included. In a subset of bvFTD and PPD cases, Ekman 60 faces test scores for social cognition were available. CSF synaptosomal-associated protein 25 (SNAP25), neurogranin (Ng), neuronal pentraxin 2 (NPTX2), and glutamate receptor 4 (GluR4) were measured, along with neurofilament light (NfL), and compared between groups using analysis of covariance (ANCOVA) and logistic regression. Diagnostic accuracy was assessed using ROC analyses, and biomarker panels were selected using Wald's backward selection. Correlations with cognitive measures were performed using Pearson's partial correlation analysis. RESULTS NPTX2 concentrations were lower in the bvFTD group compared with PPD (p < 0.001) and controls (p = 0.003) but not compared with AD. Concentrations of SNAP25 (p < 0.001) and Ng (p < 0.001) were elevated in patients with AD versus those with bvFTD and controls. The modeled panel for differential diagnosis of bvFTD versus PPD consisted of NfL and NPTX2 (AUC = 0.96, CI: 0.93-0.99, p < 0.001). In bvFTD versus AD, the modeled panel consisted of NfL, SNAP25, Ng, and GluR4 (AUC = 0.86, CI: 0.79-0.92, p < 0.001). In bvFTD, lower NPTX2 (Pearson's r = 0.29, p = 0.036) and GluR4 (Pearson's r = 0.34, p = 0.014) concentrations were weakly associated with worse performance of total cognitive score. Lower GluR4 concentrations were also associated with worse MMSE scores (Pearson's r = 0.41, p = 0.002) as well as with worse executive functioning (Pearson's r = 0.36, p = 0.011) in bvFTD. There were no associations between synaptic markers and social cognition or disease severity in bvFTD. CONCLUSION Our findings of involvement of NTPX2 in bvFTD but not PPD contribute towards better understanding of bvFTD disease pathology.
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Affiliation(s)
- Shreyasee Das
- Department of Laboratory Medicine, Neurochemistry Laboratory, Amsterdam, UMC location VrijeUniversiteit Amsterdam, Boelelaan 1117, Amsterdam, 1081 HV, The Netherlands
- ADx NeuroSciences, Technologiepark-Zwijnaarde 6, 9052, Gent, Belgium
| | - Marie-Paule E van Engelen
- Neurology, Amsterdam UMC location VUmc, Alzheimer Center Amsterdam, VrijeUniversiteit Amsterdam, De Boelelaan 1118, Amsterdam, 1081 HZ, The Netherlands
- Amsterdam Neuroscience, Neurodegeneration, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - Julie Goossens
- ADx NeuroSciences, Technologiepark-Zwijnaarde 6, 9052, Gent, Belgium
| | - Dirk Jacobs
- ADx NeuroSciences, Technologiepark-Zwijnaarde 6, 9052, Gent, Belgium
| | - Bram Bongers
- Department of Laboratory Medicine, Neurochemistry Laboratory, Amsterdam, UMC location VrijeUniversiteit Amsterdam, Boelelaan 1117, Amsterdam, 1081 HV, The Netherlands
| | - Jay L P Fieldhouse
- Neurology, Amsterdam UMC location VUmc, Alzheimer Center Amsterdam, VrijeUniversiteit Amsterdam, De Boelelaan 1118, Amsterdam, 1081 HZ, The Netherlands
- Amsterdam Neuroscience, Neurodegeneration, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - Yolande A L Pijnenburg
- Neurology, Amsterdam UMC location VUmc, Alzheimer Center Amsterdam, VrijeUniversiteit Amsterdam, De Boelelaan 1118, Amsterdam, 1081 HZ, The Netherlands
- Amsterdam Neuroscience, Neurodegeneration, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | - Charlotte E Teunissen
- Department of Laboratory Medicine, Neurochemistry Laboratory, Amsterdam, UMC location VrijeUniversiteit Amsterdam, Boelelaan 1117, Amsterdam, 1081 HV, The Netherlands
- Neurology, Amsterdam UMC location VUmc, Alzheimer Center Amsterdam, VrijeUniversiteit Amsterdam, De Boelelaan 1118, Amsterdam, 1081 HZ, The Netherlands
- Amsterdam Neuroscience, Neurodegeneration, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands
| | | | - Inge M W Verberk
- Department of Laboratory Medicine, Neurochemistry Laboratory, Amsterdam, UMC location VrijeUniversiteit Amsterdam, Boelelaan 1117, Amsterdam, 1081 HV, The Netherlands.
- Neurology, Amsterdam UMC location VUmc, Alzheimer Center Amsterdam, VrijeUniversiteit Amsterdam, De Boelelaan 1118, Amsterdam, 1081 HZ, The Netherlands.
- Amsterdam Neuroscience, Neurodegeneration, De Boelelaan 1085, Amsterdam, 1081 HV, The Netherlands.
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Uzay B, Kavalali ET. Genetic disorders of neurotransmitter release machinery. Front Synaptic Neurosci 2023; 15:1148957. [PMID: 37066095 PMCID: PMC10102358 DOI: 10.3389/fnsyn.2023.1148957] [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: 01/20/2023] [Accepted: 03/10/2023] [Indexed: 04/03/2023] Open
Abstract
Synaptic neurotransmitter release is an evolutionarily conserved process that mediates rapid information transfer between neurons as well as several peripheral tissues. Release of neurotransmitters are ensured by successive events such as synaptic vesicle docking and priming that prepare synaptic vesicles for rapid fusion. These events are orchestrated by interaction of different presynaptic proteins and are regulated by presynaptic calcium. Recent studies have identified various mutations in different components of neurotransmitter release machinery resulting in aberrant neurotransmitter release, which underlie a wide spectrum of psychiatric and neurological symptoms. Here, we review how these genetic alterations in different components of the core neurotransmitter release machinery affect the information transfer between neurons and how aberrant synaptic release affects nervous system function.
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Affiliation(s)
- Burak Uzay
- Vanderbilt Brain Institute, Nashville, TN, United States
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
| | - Ege T. Kavalali
- Vanderbilt Brain Institute, Nashville, TN, United States
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States
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3
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Özdemir Ç, Şahin N, Edgünlü T. Vesicle trafficking with snares: a perspective for autism. Mol Biol Rep 2022; 49:12193-12202. [PMID: 36198849 DOI: 10.1007/s11033-022-07970-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/21/2022] [Indexed: 11/30/2022]
Abstract
Vesicle-mediated membrane traffic is the mechanism fundamental to many biological events, especially the release of neurotransmitters. The main proteins of the mechanism that mediates membrane fusion in vesicle-mediated membrane traffic are N-ethylmaleimide sensitive factor (NSF) supplemental protein (SNAP) receptor (SNAREs) proteins. SNAREs are classified into vesicle-associated SNAREs (vesicle-SNAREs/v-SNAREs) and target membrane-associated SNAREs (target-SNARE/t-SNAREs). Autism spectrum disorders (ASD) are neurodevelopmental disorders characterized by many symptoms, especially complications in social communication and stereotypical behaviours. Defects in synaptogenesis and neurotransmission, oxidative stress, and developmental defects in the early stages of development are defined in the pathogenesis of the disease. SNARE proteins are on the basis of synaptogenesis and neurotransmission. Although the formation mechanisms and underlying causes of the SNARE complex are not fully understood, expression differences, polymorphisms, abnormal expressions or dysfunctions of the proteins that make up the SNARE complex have been associated with many neurodevelopmental diseases, including autism. Further understanding of SNARE mechanisms is crucial both for understanding ASD and for developing new treatments. In this review, the formation mechanisms of the SNARE complex and the roles of various factors involved in this process are explained. In addition, a brief evaluation of clinical and basic studies on the SNARE complex in autism spectrum disorders was made.
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Affiliation(s)
- Çilem Özdemir
- Department of Medical Biology, Health Sciences Institution, Muğla Sıtkı Koçman University, Mugla, Turkey
| | - Nilfer Şahin
- Department of Child and Adolescent Mental Health Diseases School of Medicine, Muğla Sıtkı Koçman University, Mugla, Turkey
| | - Tuba Edgünlü
- Department of Medical Biology, School of Medicine, Muğla Sıtkı Koçman University, 48000, Mugla, Turkey.
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Sato T, Oda K, Sakai S, Kato R, Yamamori S, Itakura M, Kodera Y, Nishizawa M, Sasaoka T, Onodera O, Yokoyama M. Importance of the Q/N-rich segment for protein stability of endogenous mouse TDP-43. Sci Rep 2022; 12:14923. [PMID: 36056157 PMCID: PMC9440050 DOI: 10.1038/s41598-022-19153-0] [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: 11/25/2021] [Accepted: 08/24/2022] [Indexed: 11/09/2022] Open
Abstract
TAR DNA-binding protein 43 kDa (TDP-43), a nuclear protein, plays an important role in the molecular pathogenesis of amyotrophic lateral sclerosis (ALS). The long-disordered C-terminal region (CTR) of TDP-43 is known to be aggregation-prone and a hotspot for ALS mutations, so elucidation of the physiological function of CTR will provide insights into the pathogenesis of ALS. The CTR has two Gly, aromatic, and Ser-rich (GaroS) segments and an amyloidogenic core divided into a hydrophobic patch (HP) and a Gln/Asn (Q/N)-rich segment. Although TDP-43 lacking the CTR is known to be unstable, as observed in knock-in mice, it is unclear which of these segments contributes to the stability of TDP-43. Here, we generated 12 mouse lines lacking the various sub-regions of CTR by genome editing and compared the embryonic lethality of homozygotes, and protein and mRNA expression levels of TDP-43. We demonstrated the functional diversity of the four segments of CTR, finding that the presence of the Q/N-rich segment greatly restored the protein stability of TDP-43. In addition, we found that the second GaroS deletion did not affect protein stability and mouse development.
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Affiliation(s)
- Toshiya Sato
- Department of Laboratory Animal Science, Kitasato University School of Medicine, Sagamihara, 252-0374, Japan. .,Center for Genetic Studies of Integrated Biological Functions, Kitasato University School of Medicine, Sagamihara, 252-0374, Japan. .,Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan.
| | - Kanako Oda
- Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Seiko Sakai
- Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Rika Kato
- Center for Genetic Studies of Integrated Biological Functions, Kitasato University School of Medicine, Sagamihara, 252-0374, Japan
| | - Saori Yamamori
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, 252-0374, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, 252-0374, Japan
| | - Yoshio Kodera
- Department of Physics, Kitasato University School of Science, Sagamihara, 252-0373, Japan
| | - Masatoyo Nishizawa
- Department of Neurology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan.,Department of Nursing, Niigata University of Health and Welfare, Niigata, 950-3198, Japan
| | - Toshikuni Sasaoka
- Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Osamu Onodera
- Department of Neurology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Minesuke Yokoyama
- Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan.,Central Institute for Experimental Animals, Kawasaki, 210-0821, Japan
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Mpoulimari I, Zintzaras E. Synthesis of genetic association studies on autism spectrum disorders using a genetic model-free approach. Psychiatr Genet 2022; 32:91-104. [PMID: 35353796 DOI: 10.1097/ypg.0000000000000316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Autism spectrum disorder (ASD) is a clinically and genetically heterogeneous group of neurodevelopmental disorders. Despite the extensive efforts of scientists, the etiology of ASD is far from completely elucidated. In an effort to enlighten the genetic architecture of ASDs, a meta-analysis of all available genetic association studies (GAS) was conducted. METHODS We searched in the Human Genome Epidemiology Navigator (HuGE Navigator) and PubMed for available case-control GAS of ASDs. The threshold for meta-analysis was two studies per genetic variant. The association between genotype distribution and ASDs was examined using the generalized linear odds ratio (ORG). For variants with available allele frequencies, the examined model was the allele contrast. RESULTS Overall, 57 candidate genes and 128 polymorphisms were investigated in 159 articles. In total 28 genetic polymorphisms have been shown to be associated with ASDs, that are harbored in 19 genes. Statistically significant results were revealed for the variants of the following genes adenosine deaminase (ADA), bone marrow stromal cell antigen-1 (CD157/BST1), Dopamine receptor D1 (DRD1), engrailed homolog 2 (EN2), met proto-oncogene (MET), methylenetetrahydrofolate reductase (MTHFR), solute carrier family 6 member 4 (SLC6A4), Synaptosomal-associated protein, 25kDa (SNAP-25) and vitamin D receptor (VDR). In the allele contrast model of cases versus healthy controls, significant associations were observed for Adrenoceptor Alpha 1B (ADRA1B), acetyl serotonin O - methyltransferase (ASMT), complement component 4B (C4B), dopamine receptor D3 (DRD3), met proto-oncogene (MET), neuroligin 4, X-linked (NLGN4), neurexin 1 (NRXN1), oxytocin receptor (OXTR), Serine/Threonine-Protein Kinase PFTAIRE-1 (PFTK1), Reelin (RELN) and Ras-like without CAAX 2 (RIT2). CONCLUSION These significant findings provide further evidence for genetic factors' implication in ASDs offering new perspectives in means of prevention and prognosis.
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Affiliation(s)
- Ioanna Mpoulimari
- Department of Biomathematics, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Elias Zintzaras
- Department of Biomathematics, Faculty of Medicine, University of Thessaly, Larissa, Greece
- Department of Medicine, The Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA
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6
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Saito N, Itakura M, Sasaoka T. D1 Receptor Mediated Dopaminergic Neurotransmission Facilitates Remote Memory of Contextual Fear Conditioning. Front Behav Neurosci 2022; 16:751053. [PMID: 35309682 PMCID: PMC8925912 DOI: 10.3389/fnbeh.2022.751053] [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: 07/31/2021] [Accepted: 01/21/2022] [Indexed: 11/13/2022] Open
Abstract
Dopaminergic neurotransmission via dopamine D1 receptors (D1Rs) is considered to play an important role not only in reward-based learning but also in aversive learning. The contextual and auditory cued fear conditioning tests involve the processing of classical fear conditioning and evaluates aversive learning memory. It is possible to evaluate aversive learning memory in two different types of neural transmission circuits. In addition, when evaluating the role of dopaminergic neurotransmission via D1R, to avoid the effects in D1R-mediated neural circuitry alterations during development, it is important to examine using mice who D1R expression in the mature stage is suppressed. Herein, we investigated the role of dopaminergic neurotransmission via D1Rs in aversive memory formation in contextual and auditory cued fear conditioning tests using D1R knockdown (KD) mice, in which the expression of D1Rs could be conditionally and reversibly controlled with doxycycline (Dox) treatment. For aversive memory, we examined memory formation using recent memory 1 day after conditioning, and remote memory 4 weeks after conditioning. Furthermore, immunostaining of the brain tissues of D1RKD mice was performed after aversive footshock stimulation to investigate the distribution of activated c-Fos, an immediate-early gene, in the hippocampus (CA1, CA3, dentate gyrus), striatum, amygdala, and prefrontal cortex during aversive memory formation. After aversive footshock stimulation, immunoblotting was performed using hippocampal, striatal, and amygdalar samples from D1RKD mice to investigate the increase in the amount of c-Fos and phosphorylated SNAP-25 at Ser187 residue. When D1R expression was suppressed using Dox, behavioral experiments revealed impaired contextual fear learning in remote aversion memory following footshock stimulation. Furthermore, expression analysis showed a slight increase in the post-stimulation amount of c-Fos in the hippocampus and striatum, and a significant increase in the amount of phosphorylated SNAP-25 in the hippocampus, striatum, and prefrontal cortex before and after stimulation. These findings indicate that deficiency in D1R-mediated dopaminergic neurotransmission is an important factor in impairing contextual fear memory formation for remote memory.
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Affiliation(s)
- Nae Saito
- Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University, Niigata, Japan
- Department of Molecular and Cellular Medicine, Graduate School of Medical and Dental Sciences, Niigata University, Niigata, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Japan
| | - Toshikuni Sasaoka
- Department of Comparative and Experimental Medicine, Brain Research Institute, Niigata University, Niigata, Japan
- *Correspondence: Toshikuni Sasaoka,
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7
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Yamamoto Y, Moriai H, Yokoyama T, Nakamuta N. Immunohistochemical distribution of proteins involved in glutamate release in subepithelial sensory nerve endings of rat epiglottis. Histochem Cell Biol 2021; 157:51-63. [PMID: 34613496 DOI: 10.1007/s00418-021-02038-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/26/2021] [Indexed: 11/25/2022]
Abstract
To elucidate the efferent functions of sensory nerve endings, the distribution of calretinin and vesicular glutamate transporter 1 (VGLUT1) in laryngeal laminar nerve endings and the immunohistochemical distribution of proteins associated with synaptic vesicle release, i.e., t-SNARE (SNAP25 and syntaxin 1), v-SNARE (VAMP1 and VAMP2), synaptotagmin 1 (Syt1), bassoon, and piccolo, were examined. Subepithelial laminar nerve endings immunoreactive for Na+-K+-ATPase α3-subunit (NKAα3) were largely distributed in the whole-mount preparation of the epiglottic mucosa, and several endings were also immunoreactive for calretinin. VGLUT1 immunoreactivity was observed within terminal part near the outline of the small processes of NKAα3-immunoreactive nerve ending. SNAP25, syntaxin 1, and VAMP1 immunoreactivities were detected in terminal parts of calretinin-immunoreactive endings, whereas VAMP2 immunoreactivity was only observed in a few terminals. Terminal parts immunoreactive for calretinin and/or VGLUT1 also exhibited immunoreactivities for Syt1, Ca2+ sensor for membrane trafficking, and for bassoon and piccolo, presynaptic scaffold proteins. The presence of vesicular release-related proteins, including SNARE proteins, in the terminals of laryngeal laminar endings indicate that intrinsic glutamate modulates their afferent activity in an autocrine-like manner.
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Affiliation(s)
- Yoshio Yamamoto
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate, 020-8550, Japan.
| | - Hisae Moriai
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate, 020-8550, Japan
| | - Takuya Yokoyama
- Department of Anatomy (Cell Biology), Iwate Medical University, 1-1-1 Idaidori, Yahaba, Iwate, 028-3694, Japan
| | - Nobuaki Nakamuta
- Laboratory of Veterinary Anatomy and Cell Biology, Faculty of Agriculture, Iwate University, 18-8, Ueda 3-chome, Morioka, Iwate, 020-8550, Japan
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Wang Z, Li J, Zhang T, Lu T, Wang H, Jia M, Liu J, Xiong J, Zhang D, Wang L. Family-based association study identifies SNAP25 as a susceptibility gene for autism in the Han Chinese population. Prog Neuropsychopharmacol Biol Psychiatry 2021; 105:109985. [PMID: 32479779 DOI: 10.1016/j.pnpbp.2020.109985] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Revised: 05/09/2020] [Accepted: 05/26/2020] [Indexed: 11/18/2022]
Abstract
Autism is a neurodevelopmental disorder with high heritability. Synaptosome associated protein 25 (SNAP25) encodes a presynaptic membrane-binding protein. It plays a crucial role in neurotransmission and may be involved in the pathogenesis of autism. However, the association between SNAP25 and autism in the Han Chinese population remains unclear. To investigate whether single nucleotide polymorphisms (SNPs) in SNAP25 contribute to the risk of autism, we performed a family-based association study of 14 tagSNPs in SNAP25 in 640 Han Chinese autism trios. Our results demonstrated that rs363018 in SNAP25 was significantly associated with autism under both additive (A > G, Z = 3.144, P = .0017) and recessive models (A > G, Z = 3.055, P = .0023) after Bonferroni correction (P < .0036). An additional SNP, rs8636, was nominally associated with autism under the recessive model (C > T, Z = 1.972, P = .0487). Haplotype-based association test revealed that haplotypes A-T (Z = 2.038, P = .0415) and G-T (Z = -3.114, P = .0018) of rs363018-rs362582 were significantly associated with autism after the permutation test (P = .0158). These findings suggest that SNAP25 may represent a susceptibility gene for autism in the Han Chinese population.
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Affiliation(s)
- Ziqi Wang
- Peking University Sixth Hospital, Beijing 100191, China; Peking University Institute of Mental Health, Beijing 100191, China; NHC Key Laboratory of Mental Health (Peking University), Beijing 100191, China; National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China
| | - Jun Li
- Peking University Sixth Hospital, Beijing 100191, China; Peking University Institute of Mental Health, Beijing 100191, China; NHC Key Laboratory of Mental Health (Peking University), Beijing 100191, China; National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China
| | - Tian Zhang
- Peking University Sixth Hospital, Beijing 100191, China; Peking University Institute of Mental Health, Beijing 100191, China; NHC Key Laboratory of Mental Health (Peking University), Beijing 100191, China; National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China
| | - Tianlan Lu
- Peking University Sixth Hospital, Beijing 100191, China; Peking University Institute of Mental Health, Beijing 100191, China; NHC Key Laboratory of Mental Health (Peking University), Beijing 100191, China; National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China
| | - Han Wang
- Peking University Sixth Hospital, Beijing 100191, China; Peking University Institute of Mental Health, Beijing 100191, China; NHC Key Laboratory of Mental Health (Peking University), Beijing 100191, China; National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China
| | - Meixiang Jia
- Peking University Sixth Hospital, Beijing 100191, China; Peking University Institute of Mental Health, Beijing 100191, China; NHC Key Laboratory of Mental Health (Peking University), Beijing 100191, China; National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China
| | - Jing Liu
- Peking University Sixth Hospital, Beijing 100191, China; Peking University Institute of Mental Health, Beijing 100191, China; NHC Key Laboratory of Mental Health (Peking University), Beijing 100191, China; National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China.
| | - Jun Xiong
- Haidian Maternal & Child Health Hospital, Beijing 100080, China.
| | - Dai Zhang
- Peking University Sixth Hospital, Beijing 100191, China; Peking University Institute of Mental Health, Beijing 100191, China; NHC Key Laboratory of Mental Health (Peking University), Beijing 100191, China; National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Lifang Wang
- Peking University Sixth Hospital, Beijing 100191, China; Peking University Institute of Mental Health, Beijing 100191, China; NHC Key Laboratory of Mental Health (Peking University), Beijing 100191, China; National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China.
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9
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Kakizaki T, Ohshiro T, Itakura M, Konno K, Watanabe M, Mushiake H, Yanagawa Y. Rats deficient in the GAD65 isoform exhibit epilepsy and premature lethality. FASEB J 2020; 35:e21224. [PMID: 33236473 DOI: 10.1096/fj.202001935r] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 10/27/2020] [Accepted: 11/11/2020] [Indexed: 02/02/2023]
Abstract
GABA is synthesized by glutamate decarboxylase (GAD), which has two isoforms, namely, GAD65 and GAD67, encoded by the Gad2 and Gad1 genes, respectively. GAD65-deficient (Gad2-/- ) mice exhibit a reduction in brain GABA content after 1 month of age and show spontaneous seizures in adulthood. Approximately 25% of Gad2-/- mice died by 6 months of age. Our Western blot analysis demonstrated that the protein expression ratio of GAD65 to GAD67 in the brain was greater in rats than in mice during postnatal development, suggesting that the contribution of each GAD isoform to GABA functions differs between these two species. To evaluate whether GAD65 deficiency causes different phenotypes between rats and mice, we generated Gad2-/- rats using TALEN genome editing technology. Western blot and immunohistochemical analyses with new antibodies demonstrated that the GAD65 protein was undetectable in the Gad2-/- rat brain. Gad2-/- pups exhibited spontaneous seizures and paroxysmal discharge in EEG at postnatal weeks 3-4. More than 80% of the Gad2-/- rats died at postnatal days (PNDs) 17-23. GABA content in Gad2-/- brains was significantly lower than those in Gad2+/- and Gad2+/+ brains at PND17-19. These results suggest that the low levels of brain GABA content in Gad2-/- rats may lead to epilepsy followed by premature death, and that Gad2-/- rats are more severely affected than Gad2-/- mice. Considering that the GAD65/GAD67 ratio in human brains is more similar to that in rat brains than in mouse brains, Gad2-/- rats would be useful for further investigating the roles of GAD65 in vivo.
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Affiliation(s)
- Toshikazu Kakizaki
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Tomokazu Ohshiro
- Department of Physiology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Sagamihara, Japan
| | - Kohtarou Konno
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo, Japan
| | - Hajime Mushiake
- Department of Physiology, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, Japan
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Tang BL. SNAREs and developmental disorders. J Cell Physiol 2020; 236:2482-2504. [PMID: 32959907 DOI: 10.1002/jcp.30067] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 08/20/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022]
Abstract
Members of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) family mediate membrane fusion processes associated with vesicular trafficking and autophagy. SNAREs mediate core membrane fusion processes essential for all cells, but some SNAREs serve cell/tissue type-specific exocytic/endocytic functions, and are therefore critical for various aspects of embryonic development. Mutations or variants of their encoding genes could give rise to developmental disorders, such as those affecting the nervous system and immune system in humans. Mutations to components in the canonical synaptic vesicle fusion SNARE complex (VAMP2, STX1A/B, and SNAP25) and a key regulator of SNARE complex formation MUNC18-1, produce variant phenotypes of autism, intellectual disability, movement disorders, and epilepsy. STX11 and MUNC18-2 mutations underlie 2 subtypes of familial hemophagocytic lymphohistiocytosis. STX3 mutations contribute to variant microvillus inclusion disease. Chromosomal microdeletions involving STX16 play a role in pseudohypoparathyroidism type IB associated with abnormal imprinting of the GNAS complex locus. In this short review, I discuss these and other SNARE gene mutations and variants that are known to be associated with a variety developmental disorders, with a focus on their underlying cellular and molecular pathological basis deciphered through disease modeling. Possible pathogenic potentials of other SNAREs whose variants could be disease predisposing are also speculated upon.
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Affiliation(s)
- Bor L Tang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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11
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Clarke MTM, Brinkmalm A, Foiani MS, Woollacott IOC, Heller C, Heslegrave A, Keshavan A, Fox NC, Schott JM, Warren JD, Blennow K, Zetterberg H, Rohrer JD. CSF synaptic protein concentrations are raised in those with atypical Alzheimer's disease but not frontotemporal dementia. Alzheimers Res Ther 2019; 11:105. [PMID: 31847891 PMCID: PMC6918699 DOI: 10.1186/s13195-019-0564-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 12/04/2019] [Indexed: 02/07/2023]
Abstract
BACKGROUND Increased CSF levels of a number of synaptic markers have been reported in Alzheimer's disease (AD), but little is known about their concentrations in frontotemporal dementia (FTD). We investigated this in three synaptic proteins, neurogranin, SNAP-25, and synaptotagmin-1. METHODS CSF samples were analysed from 66 patients with a disorder in the FTD spectrum and 19 healthy controls. Patients were stratified by their tau to Aβ42 ratio: those with a ratio of > 1 considered as having likely AD pathology, i.e. an atypical form of AD ('AD biomarker' group [n = 18]), and < 1 as likely FTD pathology ('FTD biomarker' group [n = 48]). A subgroup analysis compared those in the FTD group with likely tau (n = 7) and TDP-43 (n = 18) pathology. Concentrations of neurogranin were measured using two different ELISAs (Ng22 and Ng36), and concentrations of two SNAP-25 fragments (SNAP-25tot and SNAP-25aa40) and synaptotagmin-1 were measured via mass spectrometry. RESULTS The AD biomarker group had significantly higher concentrations of all synaptic proteins compared to controls except for synaptotagmin-1 where there was only a trend to increased levels-Ng22, AD mean 232.2 (standard deviation 138.9) pg/ml, controls 137.6 (95.9); Ng36, 225.5 (148.8) pg/ml, 130.0 (80.9); SNAP-25tot, 71.4 (27.9) pM, 53.5 (11.7); SNAP-25aa40, 14.0 (6.3), 7.9 (2.3) pM; and synaptotagmin-1, 287.7 (156.0) pM, 238.3 (71.4). All synaptic measures were significantly higher in the atypical AD group than the FTD biomarker group except for Ng36 where there was only a trend to increased levels-Ng22, 114.0 (117.5); Ng36, 171.1 (75.2); SNAP-25tot, 49.2 (16.7); SNAP-25aa40, 8.2 (3.4); and synaptotagmin-1, 197.1 (78.9). No markers were higher in the FTD biomarker group than controls. No significant differences were seen in the subgroup analysis, but there was a trend to increased levels in those with likely tau pathology. CONCLUSIONS No CSF synaptic proteins have been shown to be abnormal in those with likely FTD pathologically. Higher CSF synaptic protein concentrations of neurogranin, SNAP-25, and synaptotagmin-1 appear to be related to AD pathology.
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Affiliation(s)
- Mica T M Clarke
- Dementia Research Centre, Department of Neurodegenerative Disease, University College London, Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Ann Brinkmalm
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
| | - Martha S Foiani
- UK Dementia Research Institute at UCL, London, UK
- Department of Neurodegenerative Disease, University College London, London, UK
| | - Ione O C Woollacott
- Dementia Research Centre, Department of Neurodegenerative Disease, University College London, Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Carolin Heller
- UK Dementia Research Institute at UCL, London, UK
- Department of Neurodegenerative Disease, University College London, London, UK
| | - Amanda Heslegrave
- UK Dementia Research Institute at UCL, London, UK
- Department of Neurodegenerative Disease, University College London, London, UK
| | - Ashvini Keshavan
- Dementia Research Centre, Department of Neurodegenerative Disease, University College London, Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Nick C Fox
- Dementia Research Centre, Department of Neurodegenerative Disease, University College London, Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Jonathan M Schott
- Dementia Research Centre, Department of Neurodegenerative Disease, University College London, Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Jason D Warren
- Dementia Research Centre, Department of Neurodegenerative Disease, University College London, Queen Square Institute of Neurology, London, WC1N 3BG, UK
| | - Kaj Blennow
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- UK Dementia Research Institute at UCL, London, UK
- Department of Neurodegenerative Disease, University College London, London, UK
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
| | - Jonathan D Rohrer
- Dementia Research Centre, Department of Neurodegenerative Disease, University College London, Queen Square Institute of Neurology, London, WC1N 3BG, UK.
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The SNAP-25 Protein Family. Neuroscience 2019; 420:50-71. [DOI: 10.1016/j.neuroscience.2018.09.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 08/31/2018] [Accepted: 09/14/2018] [Indexed: 01/04/2023]
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13
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Kuwano N, Kato TA, Mitsuhashi M, Sato-Kasai M, Shimokawa N, Hayakawa K, Ohgidani M, Sagata N, Kubo H, Sakurai T, Kanba S. Neuron-related blood inflammatory markers as an objective evaluation tool for major depressive disorder: An exploratory pilot case-control study. J Affect Disord 2018; 240:88-98. [PMID: 30059939 DOI: 10.1016/j.jad.2018.07.040] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 05/31/2018] [Accepted: 07/14/2018] [Indexed: 01/23/2023]
Abstract
BACKGROUND Neuroinflammation is suggested to be a crucial factor in the pathophysiology of major depressive disorder (MDD). Analysis of neuron-derived exosomes (NDE) in peripheral blood has recently been highlighted to reveal the pathophysiology of brain diseases without using brain biopsy. Currently, human NDE studies require a considerable amount of peripheral blood to measure multiple substances inside exosomes. Previously, NDE-based clinical studies focusing on MDD have not been reported. METHODS As an exploratory pilot case-control study between healthy controls (HC) and drug-free MDD patients (each; N = 34), we searched for NDE-related blood biomarkers with a small amount of peripheral blood using a novel sandwich immunoassay between anti-neuron antibody and antibodies against CD81 (an exosome marker) and against other proteins related to neuroinflammation and synaptic functions. RESULTS Most neuron-related blood biomarkers had moderately to strongly positive correlation with CD81 (NDE), thus we normalized the above biomarkers by CD81 (quantity of each biomarker/CD81) to predict NDE-related blood substances. Interleukin 34 (IL34)/CD81 levels were significantly higher in MDD group compared to HC group. Synaptophysin (SYP), SYP/CD81, and tumor necrosis factor receptor 1 (TNFR1)/CD81 were positively correlated with severities of depression and/or various sub-symptoms. LIMITATIONS We did not actually extract NDE from peripheral blood. CONCLUSIONS Using a small amount of peripheral blood, we have successfully detected possible NDE-related blood biomarkers. This is the first study to suggest that not only SYP and TNFR1 but also IL34 are important blood biomarkers for patients with MDD. Further studies are warranted to evaluate the present study.
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Affiliation(s)
- Nobuki Kuwano
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takahiro A Kato
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan.
| | | | - Mina Sato-Kasai
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Norihiro Shimokawa
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Kohei Hayakawa
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Masahiro Ohgidani
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Noriaki Sagata
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Hiroaki Kubo
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Takeshi Sakurai
- Faculty of Medicine/International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Ibaraki, Japan
| | - Shigenobu Kanba
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
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Aoyagi K, Itakura M, Fukutomi T, Nishiwaki C, Nakamichi Y, Torii S, Makiyama T, Harada A, Ohara-Imaizumi M. VAMP7 Regulates Autophagosome Formation by Supporting Atg9a Functions in Pancreatic β-Cells From Male Mice. Endocrinology 2018; 159:3674-3688. [PMID: 30215699 DOI: 10.1210/en.2018-00447] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 09/05/2018] [Indexed: 12/24/2022]
Abstract
Dysfunctional mitochondria are observed in β-cells of diabetic patients, which are eventually removed by autophagy. Vesicle-associated membrane protein (VAMP)7, a vesicular SNARE protein, regulates autophagosome formation to maintain mitochondrial homeostasis and control insulin secretion in pancreatic β-cells. However, its molecular mechanism is largely unknown. In this study, we investigated the molecular mechanism of VAMP7-dependent autophagosome formation using VAMP7-deficient β-cells and β-cell-derived Min6 cells. VAMP7 localized in autophagy-related (Atg)9a-resident vesicles of recycling endosomes (REs), which contributed to autophagosome formation, and it interacted with Hrb, Syntaxin16, and SNAP-47. Hrb recruited VAMP7 and Atg9a from the plasma membrane to REs. Syntaxin16 and SNAP-47 mediated autophagosome formation at a step later than the proper localization of VAMP7 to Atg9a-resident vesicles. Knockdown of Hrb, Syntaxin16, and SNAP-47 resulted in defective autophagosome formation, accumulation of dysfunctional mitochondria, and impairment of glucose-stimulated insulin secretion. Our data indicate that VAMP7 and Atg9a are initially recruited to REs to organize VAMP7 and Atg9a-resident vesicles in an Hrb-dependent manner. Additionally, VAMP7 forms a SNARE complex with Syntaxin16 and SNAP-47, which may cause fusions of Atg9a-resident vesicles during autophagosome formation. Thus, VAMP7 participates in autophagosome formation by supporting Atg9a functions that contribute to maintenance of mitochondrial quality.
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Affiliation(s)
- Kyota Aoyagi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Kanagawa, Japan
| | - Toshiyuki Fukutomi
- Department of Pharmacology, Kyorin University School of Medicine, Tokyo, Japan
| | - Chiyono Nishiwaki
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Yoko Nakamichi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Seiji Torii
- Biosignal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Gunma, Japan
| | - Tomohiko Makiyama
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Akihiro Harada
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Mica Ohara-Imaizumi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
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15
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Wang X, Liu Y, Jia M, Sun X, Wang N, Li Y, Cui C. Phosphorylated SNAP25 in the CA1 regulates morphine-associated contextual memory retrieval via increasing GluN2B-NMDAR surface localization. Addict Biol 2018; 23:1067-1078. [PMID: 28884870 DOI: 10.1111/adb.12558] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 07/13/2017] [Accepted: 08/18/2017] [Indexed: 01/10/2023]
Abstract
Although our previous studies have demonstrated both protein kinase C (PKC) and GluN2B-containing N-methyl-d-aspartate receptor (GluN2B-NMDAR) play crucial roles in morphine-associated learning and memory, the relationship between them remains unexplored. In this study, we validated the enhanced PKC and membrane GluN2B protein expression in the hippocampal CA1 after morphine conditioned place preference (CPP) expression in rats. Interestingly, we also found that phosphorylation of SNAP25 at Ser187 (pSer187-SNAP25), a PKC-activated target, was significantly increased following morphine CPP expression. Blocking the pSer187-SNAP25 by intra-CA1 injection of an interfering peptide impaired morphine CPP expression and accompanied by the reduced ratio of GluN2B membrane/total in the CA1. In addition, intra-CA1 blockade of pSer187-SNAP25 did not affect natural learning and memory process as evidenced by intact sucrose-induced CPP expression and normal locomotor activity in rats. Therefore, our results reveal that enhanced pSer187-SNAP25 by PKC recruits GluN2B-NMDAR to the membrane surface in the hippocampal CA1 and mediates context-induced addiction memory retrieval. Our findings in this study fill in the missing link and provide better understanding of the molecular mechanisms involved in morphine-associated contextual memory retrieval.
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Affiliation(s)
- Xinjuan Wang
- Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience of the Ministry of Education and National Health and Family Planning Commission, Neuroscience Research Institute; Peking University; China
| | - Yan Liu
- Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience of the Ministry of Education and National Health and Family Planning Commission, Neuroscience Research Institute; Peking University; China
| | - Meng Jia
- Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience of the Ministry of Education and National Health and Family Planning Commission, Neuroscience Research Institute; Peking University; China
| | - Xiaowei Sun
- Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience of the Ministry of Education and National Health and Family Planning Commission, Neuroscience Research Institute; Peking University; China
| | - Na Wang
- Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience of the Ministry of Education and National Health and Family Planning Commission, Neuroscience Research Institute; Peking University; China
| | - Yijing Li
- Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience of the Ministry of Education and National Health and Family Planning Commission, Neuroscience Research Institute; Peking University; China
| | - Cailian Cui
- Department of Neurobiology, School of Basic Medical Sciences, Key Laboratory for Neuroscience of the Ministry of Education and National Health and Family Planning Commission, Neuroscience Research Institute; Peking University; China
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16
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Abe T, Minowa Y, Kudo H. Molecular characterization and gene expression of synaptosome-associated protein-25 (SNAP-25) in the brain during both seaward and homeward migrations of chum salmon Oncorhynchus keta. Comp Biochem Physiol A Mol Integr Physiol 2018; 217:17-25. [DOI: 10.1016/j.cbpa.2017.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 01/12/2023]
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17
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Fukuda H, Imagawa E, Hamanaka K, Fujita A, Mitsuhashi S, Miyatake S, Mizuguchi T, Takata A, Miyake N, Kramer U, Matsumoto N, Fattal-Valevski A. A novel missense SNAP25b mutation in two affected siblings from an Israeli family showing seizures and cerebellar ataxia. J Hum Genet 2018; 63:673-676. [DOI: 10.1038/s10038-018-0421-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 01/17/2018] [Accepted: 01/28/2018] [Indexed: 12/11/2022]
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A Multilevel Functional Study of a SNAP25 At-Risk Variant for Bipolar Disorder and Schizophrenia. J Neurosci 2017; 37:10389-10397. [PMID: 28972123 DOI: 10.1523/jneurosci.1040-17.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 09/08/2017] [Accepted: 09/13/2017] [Indexed: 12/16/2022] Open
Abstract
The synaptosomal-associated protein SNAP25 is a key player in synaptic vesicle docking and fusion and has been associated with multiple psychiatric conditions, including schizophrenia, bipolar disorder, and attention-deficit/hyperactivity disorder. We recently identified a promoter variant in SNAP25, rs6039769, that is associated with early-onset bipolar disorder and a higher gene expression level in human prefrontal cortex. In the current study, we showed that this variant was associated both in males and females with schizophrenia in two independent cohorts. We then combined in vitro and in vivo approaches in humans to understand the functional impact of the at-risk allele. Thus, we showed in vitro that the rs6039769 C allele was sufficient to increase the SNAP25 transcription level. In a postmortem expression analysis of 33 individuals affected with schizophrenia and 30 unaffected control subjects, we showed that the SNAP25b/SNAP25a ratio was increased in schizophrenic patients carrying the rs6039769 at-risk allele. Last, using genetics imaging in a cohort of 71 subjects, we showed that male risk carriers had an increased amygdala-ventromedial prefrontal cortex functional connectivity and a larger amygdala than non-risk carriers. The latter association has been replicated in an independent cohort of 121 independent subjects. Altogether, results from these multilevel functional studies are bringing strong evidence for the functional consequences of this allelic variation of SNAP25 on modulating the development and plasticity of the prefrontal-limbic network, which therefore may increase the vulnerability to both early-onset bipolar disorder and schizophrenia.SIGNIFICANCE STATEMENT Functional characterization of disease-associated variants is a key challenge in understanding neuropsychiatric disorders and will open an avenue in the development of personalized treatments. Recent studies have accumulated evidence that the SNARE complex, and more specifically the SNAP25 protein, may be involved in psychiatric disorders. Here, our multilevel functional studies are bringing strong evidence for the functional consequences of an allelic variation of SNAP25 on modulating the development and plasticity of the prefrontal-limbic network. These results demonstrate a common genetically driven functional alteration of a synaptic mechanism both in schizophrenia and early-onset bipolar disorder and confirm the shared genetic vulnerability between these two disorders.
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Sun XL, Yuan JF, Jin T, Cheng XQ, Wang Q, Guo J, Zhang W, Zhang Y, Lu L, Zhang Z. Physical and functional interaction of Snapin with Cav1.3 calcium channel impacts channel protein trafficking in atrial myocytes. Cell Signal 2016; 30:118-129. [PMID: 27915047 DOI: 10.1016/j.cellsig.2016.11.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/10/2016] [Accepted: 11/27/2016] [Indexed: 10/20/2022]
Abstract
The L-type Ca2+ channel (LTCC) Cav1.3 plays a critical role in generating electrical activity in atrial myocytes and cardiac pacemaker cells. However, the molecular and functional basis of Cav1.3 modulation in atrial myocytes has not yet been fully understood. By using the yeast two-hybrid system (Y2H), a Cav1.3-associated protein was screened, which was identified as Snapin. Physical interaction and co-localization between Snapin and Cav1.3 were then confirmed in both the heterologous expression system and mouse atrial myocytes. Direct interaction between them was additionally addressed in a GST pull down assay. Furthermore, both total and membrane expressions of Cav1.3 were significantly impaired by Snapin overexpression, resulting in the ubiquitin-proteasomal degradation of Cav1.3 and a consequent reduction of the densities of whole-cell ICa-L. Snapin-induced down-regulation of Cav1.3 was reversed by SNAP-23 competitively. What is more important is that the depressed-expression of Cav1.3 paralleled with enhanced-expression of Snapin was documented in atrial samples from atrial fibrillation (AF) patients. Our results provide the evidence of a direct regulatory role of Snapin on Cav1.3 channels in atrial myocytes, and highlight a potential role of Snapin in the regulation of Cav1.3 in atrial arrhythmogenesis.
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Affiliation(s)
- Xiao-Li Sun
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Ju-Fang Yuan
- Anesthesia Department of The Affiliated People's Hospital, Jiangsu University, Zhenjiang 212002, China
| | - Tao Jin
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Xiao-Qing Cheng
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Qiang Wang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Jia Guo
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China; Department of Nephrology at the First Affiliated Hospital, Zhengzhou University, Zhengzhou 450052, China
| | - Wei Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Yin Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, College of Life Science, Nanjing Normal University, Nanjing 210023, China
| | - Zhao Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Science, Nanjing Normal University, Nanjing 210023, China.
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20
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Barakauskas VE, Moradian A, Barr AM, Beasley CL, Rosoklija G, Mann JJ, Ilievski B, Stankov A, Dwork AJ, Falkai P, Morin GB, Honer WG. Quantitative mass spectrometry reveals changes in SNAP-25 isoforms in schizophrenia. Schizophr Res 2016; 177:44-51. [PMID: 26971072 PMCID: PMC5017887 DOI: 10.1016/j.schres.2016.03.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/02/2016] [Accepted: 03/04/2016] [Indexed: 11/24/2022]
Abstract
SNAP-25 and syntaxin are presynaptic terminal SNARE proteins altered in amount and function in schizophrenia. In the ventral caudate, we observed 32% lower SNAP-25 and 26% lower syntaxin, but greater interaction between the two proteins using an in vitro assay. SNAP-25 has two isoforms, SNAP-25A and B, differing by only 9 amino acids, but with different effects on neurotransmission. A quantitative mass spectrometry assay was developed to measure total SNAP-25, and proportions of SNAP-25A and B. The assay had a good linear range (50- to 150-fold) and coefficient of variation (4.5%). We studied ventral caudate samples from patients with schizophrenia (n=15) previously reported to have lower total SNAP-25 than controls (n=13). We confirmed 27% lower total SNAP-25 in schizophrenia, and observed 31% lower SNAP-25A (P=0.002) with 20% lower SNAP-25B amounts (P=0.10). Lower SNAP-25A amount correlated with greater SNAP-25-syntaxin protein-protein interactions (r=-0.41, P=0.03); the level of SNAP-25B did not. Administration of haloperidol or clozapine to rats did not mimic the changes found in schizophrenia. The findings suggest that lower levels of SNAP-25 in schizophrenia may represent a greater effect of the illness on the SNAP-25A isoform. This in turn could contribute to the greater interaction between SNAP25 and syntaxin, and possibly disturb neurotransmission in the illness.
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Affiliation(s)
- Vilte E Barakauskas
- BC Mental Health and Addictions Research Institute, Vancouver, BC,Department of Psychiatry, University of British Columbia, Vancouver, BC
| | - Annie Moradian
- Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC
| | - Alasdair M. Barr
- BC Mental Health and Addictions Research Institute, Vancouver, BC,Department of Anesthesiology, Pharmacology & Therapeutics, University of British Columbia, Vancouver, BC
| | - Clare L Beasley
- BC Mental Health and Addictions Research Institute, Vancouver, BC,Department of Psychiatry, University of British Columbia, Vancouver, BC
| | - Gorazd Rosoklija
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute; and Department of Psychiatry, Columbia University, New York, NY, USA,Macedonian Academy of Sciences and Arts, University “SS. Cyril and Methodius,” Skopje, Macedonia
| | - J John Mann
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute; and Department of Psychiatry, Columbia University, New York, NY, USA
| | - Boro Ilievski
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute; and Department of Psychiatry, Columbia University, New York, NY, USA,Institute for Pathology, University “SS. Cyril and Methodius,” Skopje, Macedonia
| | - Aleksandar Stankov
- Institute of Forensic Medicine, Criminology and Medical Deontology, University “SS. Cyril and Methodius,” Skopje, Macedonia
| | - Andrew J Dwork
- Department of Molecular Imaging and Neuropathology, New York State Psychiatric Institute; and Department of Psychiatry, Columbia University, New York, NY, USA,Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Peter Falkai
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilians-University, Munich, Germany
| | - Gregg B Morin
- Michael Smith Genome Sciences Centre, British Columbia Cancer Agency, Vancouver, BC, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.
| | - William G Honer
- BC Mental Health and Addictions Research Institute, Vancouver, BC, Canada; Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada.
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Zieminska E, Lenart J, Lazarewicz JW. Select putative neurodevelopmental toxins modify SNAP-25 expression in primary cultures of rat cerebellar granule cells. Toxicology 2016; 370:86-93. [PMID: 27693314 DOI: 10.1016/j.tox.2016.09.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 09/22/2016] [Accepted: 09/26/2016] [Indexed: 11/19/2022]
Abstract
A presynaptic protein SNAP-25 belonging to SNARE complex which is instrumental in intracellular vesicular trafficking and exocytosis, has been implicated in hyperactivity and cognitive abilities in some neuropsychiatric disorders. The unclear etiology of the behavior disrupting neurodevelopmental disabilities in addition to genetic causes most likely involves environmental factors. The aim of this in vitro study was to test if various suspected developmental neurotoxins can alter SNAP-25 mRNA and protein expression in neurons. Real-time PCR and Western blotting analyses were used to assess SNAP-25 mRNA and protein levels in primary cultures of rat cerebellar granule cells (CGCs). The test substances: tetrabromobisphenol-A (TBBPA), thimerosal (TH), silver nanoparticles (NAg), valproic acid (VPA) and thalidomide (THAL), were administered to CGC cultures at subtoxic concentrations for 24h. The results demonstrated that SNAP-25 mRNA levels were increased by 49 and 66% by TBBPA and THAL, respectively, whereas VPA and NAg reduced these levels to 48 and 64% of the control, respectively. The SNAP-25 protein content in CGCs was increased by 79% by TBBPA, 25% by THAL and 21% by NAg; VPA and TH reduced these levels to 73 and 69% of the control, respectively. The variety of changes in SNAP-25 expression on mRNA and protein level suggests the diversity of the mechanism of action of the test substances. This initial study provided no data on concentration-effect relations and on functional changes in CGCs. However it is the first to demonstrate the effect of different compounds that are suspected of causing neurodevelopmental disabilities on SNAP-25 expression. These results suggest that this protein may be a common target for not only inherited but also environmental modifications linked to behavioral deficits in neurodevelopmental disabilities.
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Affiliation(s)
- Elzbieta Zieminska
- Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland.
| | - Jacek Lenart
- Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland.
| | - Jerzy W Lazarewicz
- Department of Neurochemistry, Mossakowski Medical Research Centre, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland.
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22
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Aoyagi K, Ohara-Imaizumi M, Itakura M, Torii S, Akimoto Y, Nishiwaki C, Nakamichi Y, Kishimoto T, Kawakami H, Harada A, Takahashi M, Nagamatsu S. VAMP7 Regulates Autophagy to Maintain Mitochondrial Homeostasis and to Control Insulin Secretion in Pancreatic β-Cells. Diabetes 2016; 65:1648-59. [PMID: 26953164 DOI: 10.2337/db15-1207] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 03/03/2016] [Indexed: 11/13/2022]
Abstract
VAMP7 is a SNARE protein that mediates specific membrane fusions in intracellular trafficking and was recently reported to regulate autophagosome formation. However, its function in pancreatic β-cells is largely unknown. To elucidate the physiological role of VAMP7 in β-cells, we generated pancreatic β-cell-specific VAMP7 knockout (Vamp7(flox/Y);Cre) mice. VAMP7 deletion impaired glucose-stimulated ATP production and insulin secretion, though VAMP7 was not localized to insulin granules. VAMP7-deficient β-cells showed defective autophagosome formation and reduced mitochondrial function. p62/SQSTM1, a marker protein for defective autophagy, was selectively accumulated on mitochondria in VAMP7-deficient β-cells. These findings suggest that accumulation of dysfunctional mitochondria that are degraded by autophagy caused impairment of glucose-stimulated ATP production and insulin secretion in Vamp7(flox/Y);Cre β-cells. Feeding a high-fat diet to Vamp7(flox/Y);Cre mice exacerbated mitochondrial dysfunction, further decreased ATP production and insulin secretion, and consequently induced glucose intolerance. Moreover, we found upregulated VAMP7 expression in wild-type mice fed a high-fat diet and in db/db mice, a model for diabetes. Thus our data indicate that VAMP7 regulates autophagy to maintain mitochondrial quality and insulin secretion in response to pathological stress in β-cells.
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Affiliation(s)
- Kyota Aoyagi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Mica Ohara-Imaizumi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Kanagawa, Japan
| | - Seiji Torii
- Biosignal Research Center, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Japan
| | - Yoshihiro Akimoto
- Department of Anatomy, Kyorin University School of Medicine, Tokyo, Japan
| | - Chiyono Nishiwaki
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Yoko Nakamichi
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Takuma Kishimoto
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
| | - Hayato Kawakami
- Department of Anatomy, Kyorin University School of Medicine, Tokyo, Japan
| | - Akihiro Harada
- Department of Cell Biology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Masami Takahashi
- Department of Biochemistry, Kitasato University School of Medicine, Kanagawa, Japan
| | - Shinya Nagamatsu
- Department of Biochemistry, Kyorin University School of Medicine, Tokyo, Japan
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Cupertino RB, Kappel DB, Bandeira CE, Schuch JB, da Silva BS, Müller D, Bau CHD, Mota NR. SNARE complex in developmental psychiatry: neurotransmitter exocytosis and beyond. J Neural Transm (Vienna) 2016; 123:867-83. [DOI: 10.1007/s00702-016-1514-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 01/20/2016] [Indexed: 12/31/2022]
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Membrane Trafficking in Neuronal Development: Ins and Outs of Neural Connectivity. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 322:247-80. [PMID: 26940520 DOI: 10.1016/bs.ircmb.2015.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During development, neurons progress through rapid yet stereotypical shape changes to achieve proper neuronal connectivity. This morphological progression requires carefully orchestrated plasma membrane expansion, insertion of membrane components including receptors for extracellular cues into the plasma membrane and removal and trafficking of membrane materials and proteins to specific locations. This review outlines the cellular machinery of membrane trafficking that play an integral role in neuronal cell shape change and function from initial neurite formation to pathway navigation and synaptogenesis.
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Thompson PM, Cruz DA, Fucich EA, Olukotun DY, Takahashi M, Itakura M. SNAP-25a/b Isoform Levels in Human Brain Dorsolateral Prefrontal Cortex and Anterior Cingulate Cortex. MOLECULAR NEUROPSYCHIATRY 2015; 1:220-34. [PMID: 27606314 DOI: 10.1159/000441224] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 09/09/2015] [Indexed: 01/03/2023]
Abstract
SNAP-25 is a neurotransmitter vesicular docking protein which has been associated with brain disorders such as attention deficit hyperactivity disorder, bipolar disorder and schizophrenia. In this project, we were interested if clinical factors are associated with differential SNAP-25 expression. We examined the SNAP-25 isoform mRNA and protein levels in postmortem cortex Brodmann's area 9 (BA9) and BA24 (n = 29). Subjects were divided by psychiatric diagnosis, clinical variables including mood state in the last week of life and lifetime impulsiveness. We found affected subjects with a diagnosis of alcohol use disorder (AUD) had a lower level of SNAP-25b BA24 protein compared to those without AUD. Hispanic subjects had lower levels of SNAP-25a, b and BA9 mRNA than Anglo-American subjects. Subjects who smoked had a total pan (total) SNAP-25 BA9/BA24 ratio. Subjects in the group with a low level of anxious-psychotic symptoms had higher SNAP-25a BA24 mRNA compared to normal controls, and both the high and low symptoms groups had higher pan (total) SNAP-25 BA9/BA24 ratios than normal controls. These data expand our understanding of clinical factors associated with SNAP-25. They suggest that SNAP-25 total and isoform levels may be useful biomarkers beyond limited neurological and psychiatric diagnostic categories.
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Affiliation(s)
| | - Dianne A Cruz
- Departments of Psychiatry, University of Texas Health Science Center San Antonio, San Antonio, Tex., USA
| | - Elizabeth A Fucich
- Departments of Pharmacology, University of Texas Health Science Center San Antonio, San Antonio, Tex., USA
| | - Dianna Y Olukotun
- Departments of Psychiatry, University of Texas Health Science Center San Antonio, San Antonio, Tex., USA
| | - Masami Takahashi
- Department of Biochemistry, Kitasato University School of Medicine, Tokyo, Japan
| | - Makoto Itakura
- Department of Biochemistry, Kitasato University School of Medicine, Tokyo, Japan
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Abstract
Synaptosomal-associated protein of 25 kDa (SNAP-25) is a key molecule in the soluble N-ethylmaleimide-sensitive factor attachment protein (SNARE) complex mediating fast Ca(2+)-triggered release of hormones and neurotransmitters, and both splice variants, SNAP-25a and SNAP-25b, can participate in this process. Here we explore the hypothesis that minor alterations in the machinery mediating regulated membrane fusion can increase the susceptibility for metabolic disease and precede obesity and type 2 diabetes. Thus, we used a mouse mutant engineered to express normal levels of SNAP-25 but only SNAP-25a. These SNAP-25b-deficient mice were exposed to either a control or a high-fat/high-sucrose diet. Monitoring of food intake, body weight, hypothalamic function, and lipid and glucose homeostases showed that SNAP-25b-deficient mice fed with control diet developed hyperglycemia, liver steatosis, and adipocyte hypertrophy, conditions dramatically exacerbated when combined with the high-fat/high-sucrose diet. Thus, modified SNARE function regulating stimulus-dependent exocytosis can increase the vulnerability to and even provoke metabolic disease. When combined with a high-fat/high-sucrose diet, this vulnerability resulted in diabesity. Our SNAP-25b-deficient mouse may represent a diabesity model.
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Ohta E, Nihira T, Uchino A, Imaizumi Y, Okada Y, Akamatsu W, Takahashi K, Hayakawa H, Nagai M, Ohyama M, Ryo M, Ogino M, Murayama S, Takashima A, Nishiyama K, Mizuno Y, Mochizuki H, Obata F, Okano H. I2020T mutant LRRK2 iPSC-derived neurons in the Sagamihara family exhibit increased Tau phosphorylation through the AKT/GSK-3β signaling pathway. Hum Mol Genet 2015; 24:4879-900. [PMID: 26056228 DOI: 10.1093/hmg/ddv212] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 06/03/2015] [Indexed: 12/22/2022] Open
Abstract
Leucine-rich repeat kinase 2 (LRRK2) is the causative molecule of the autosomal dominant hereditary form of Parkinson's disease (PD), PARK8, which was originally defined in a study of a Japanese family (the Sagamihara family) harboring the I2020T mutation in the kinase domain. Although a number of reported studies have focused on cell death mediated by mutant LRRK2, details of the pathogenetic effect of LRRK2 still remain to be elucidated. In the present study, to elucidate the mechanism of neurodegeneration in PD caused by LRRK2, we generated induced pluripotent stem cells (iPSC) derived from fibroblasts of PD patients with I2020T LRRK2 in the Sagamihara family. We found that I2020T mutant LRRK2 iPSC-derived neurons released less dopamine than control-iPSC-derived neurons. Furthermore, we demonstrated that patient iPSC-derived neurons had a lower phospho-AKT level than control-iPSC-derived neurons, and that the former showed an increased incidence of apoptosis relative to the controls. Interestingly, patient iPSC-derived neurons exhibited activation of glycogen synthase kinase-3β (GSK-3β) and high Tau phosphorylation. In addition, the postmortem brain of the patient from whom the iPSC had been established exhibited deposition of neurofibrillary tangles as well as increased Tau phosphorylation in neurons. These results suggest that I2020T LRRK2-iPSC could be a promising new tool for reproducing the pathology of PD in the brain caused by the I2020T mutation, and applicable as a model in studies of targeted therapeutics.
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Affiliation(s)
- Etsuro Ohta
- R & D Center for Cell Design, Institute for Regenerative Medicine and Cell Design, Kitasato University School of Allied Health Sciences, Kanagawa, Japan, Division of Clinical Immunology, Graduate School of Medical Sciences, Department of Physiology
| | - Tomoko Nihira
- Department of Neuro-Regenerative Medicine, Department of Physiology
| | - Akiko Uchino
- Department of Neurology, Graduate School of Medical Sciences, Kitasato University, Kanagawa, Japan, Department of the Brain Bank for Aging Research
| | | | - Yohei Okada
- Department of Physiology, Department of Neurology, Aichi Medical University School of Medicine, Aichi, Japan
| | - Wado Akamatsu
- Department of Physiology, Center for Genomic and Regenerative Medicine, Juntendo University School of Medicine, Tokyo, Japan
| | - Kayoko Takahashi
- Department of Medical Laboratory, Kitasato University Hospital, Kanagawa, Japan
| | | | - Makiko Nagai
- Department of Neurology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Manabu Ohyama
- Department of Dermatology, Keio University School of Medicine, Tokyo, Japan
| | - Masafuchi Ryo
- Department of Neurology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Mieko Ogino
- Department of Neurology, Kitasato University School of Medicine, Kanagawa, Japan
| | - Shigeo Murayama
- Department of the Brain Bank for Aging Research, Department of Neurology, Department of Bioresource Center (the Brain Bank for Aging Research), Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan
| | - Akihiko Takashima
- Department of Neurobiology, National Center for Geriatrics and Gerontology, Obu, Japan and
| | - Kazutoshi Nishiyama
- Department of Neurology, Graduate School of Medical Sciences, Kitasato University, Kanagawa, Japan, Department of Neurology, Kitasato University School of Medicine, Kanagawa, Japan
| | | | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Fumiya Obata
- R & D Center for Cell Design, Institute for Regenerative Medicine and Cell Design, Kitasato University School of Allied Health Sciences, Kanagawa, Japan, Division of Clinical Immunology, Graduate School of Medical Sciences
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Trier NH. Characterization of Peptide Antibodies by Epitope Mapping Using Resin-Bound and Soluble Peptides. Methods Mol Biol 2015; 1348:229-39. [PMID: 26424276 DOI: 10.1007/978-1-4939-2999-3_20] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Characterization of peptide antibodies through identification of their target epitopes is of utmost importance. Understanding antibody specificity at the amino acid level provides the key to understand the specific interaction between antibodies and their epitopes and their use as research and diagnostic tools as well as therapeutic agents. This chapter describes a straightforward strategy for mapping of continuous peptide antibody epitopes using resin-bound and soluble peptides. The approach combines three different types of peptide sets for full characterization of peptide antibodies: (1) overlapping peptides, used to locate antigenic regions; (2) truncated peptides, used to identify the minimal peptide length required for antibody binding; and (3) substituted peptides, used to identify the key residues important for antibody binding and to determine the specific contribution of key residues. For initial screening resin-bound peptides are used for epitope estimation, while soluble peptides subsequently are used for fine mapping. The combination of resin-bound peptides and soluble peptides for epitope mapping provides a time-sparing and straightforward approach for characterization of peptide antibodies.
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Affiliation(s)
- Nicole Hartwig Trier
- Department of Autoimmunology and Biomarkers, Statens Serum Institut, Artillerivej 5, 2300, Copenhagen, Denmark.
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29
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Shen XM, Selcen D, Brengman J, Engel AG. Mutant SNAP25B causes myasthenia, cortical hyperexcitability, ataxia, and intellectual disability. Neurology 2014; 83:2247-55. [PMID: 25381298 DOI: 10.1212/wnl.0000000000001079] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To identify and characterize the molecular basis of a syndrome associated with myasthenia, cortical hyperexcitability, cerebellar ataxia, and intellectual disability. METHODS We performed in vitro microelectrode studies of neuromuscular transmission, performed exome and Sanger sequencing, and analyzed functional consequences of the identified mutation in expression studies. RESULTS Neuromuscular transmission at patient endplates was compromised by reduced evoked quantal release. Exome sequencing identified a dominant de novo variant, p.Ile67Asn, in SNAP25B, a SNARE protein essential for exocytosis of synaptic vesicles from nerve terminals and of dense-core vesicles from endocrine cells. Ca(2+)-triggered exocytosis is initiated when synaptobrevin attached to synaptic vesicles (v-SNARE) assembles with SNAP25B and syntaxin anchored in the presynaptic membrane (t-SNAREs) into an α-helical coiled-coil held together by hydrophobic interactions. Pathogenicity of the Ile67Asn mutation was confirmed by 2 measures. First, the Ca(2+) triggered fusion of liposomes incorporating v-SNARE with liposomes containing t-SNAREs was hindered when t-SNAREs harbored the mutant SNAP25B moiety. Second, depolarization of bovine chromaffin cells transfected with mutant SNAP25B or with mutant plus wild-type SNAP25B markedly reduced depolarization-evoked exocytosis compared with wild-type transfected cells. CONCLUSION Ile67Asn variant in SNAP25B is pathogenic because it inhibits synaptic vesicle exocytosis. We attribute the deleterious effects of the mutation to disruption of the hydrophobic α-helical coiled-coil structure of the SNARE complex by replacement of a highly hydrophobic isoleucine by a strongly hydrophilic asparagine.
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Affiliation(s)
- Xin-Ming Shen
- From the Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN.
| | - Duygu Selcen
- From the Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN
| | - Joan Brengman
- From the Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN
| | - Andrew G Engel
- From the Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN.
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30
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Chen G, Hu T, Li Q, Li J, Jia Y, Wang Z. Expression of synaptosomal-associated protein-25 in the rat brain after subarachnoid hemorrhage. Neural Regen Res 2014; 8:2693-702. [PMID: 25206580 PMCID: PMC4145993 DOI: 10.3969/j.issn.1673-5374.2013.29.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/09/2013] [Indexed: 11/18/2022] Open
Abstract
Synaptosomal-associated protein-25 is an important factor for synaptic functions and cognition. In this study, subarachnoid hemorrhage models with spatial learning disorder were established through a blood injection into the chiasmatic cistern. Immunohistochemical staining and western blot analysis results showed that synaptosomal-associated protein-25 expression in the temporal lobe, hippocampus, and cerebellum significantly lower at days 1 and 3 following subarachnoid morrhage. Our findings indicate that synaptosomal-associated protein-25 expression was down-regulated in the rat brain after subarachnoid hemorrhage.
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Affiliation(s)
- Gang Chen
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
| | - Tong Hu
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China ; Department of Neurosurgery, Yixing People's Hospital, Yixing 214200, Jiangsu Province, China
| | - Qi Li
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
| | - Jianke Li
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
| | - Yang Jia
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
| | - Zhong Wang
- Department of Neurosurgery, the First Affiliated Hospital of Soochow University, Suzhou 215006, Jiangsu Province, China
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31
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Brinkmalm A, Brinkmalm G, Honer WG, Moreno JA, Jakobsson J, Mallucci GR, Zetterberg H, Blennow K, Öhrfelt A. Targeting synaptic pathology with a novel affinity mass spectrometry approach. Mol Cell Proteomics 2014; 13:2584-92. [PMID: 24973420 DOI: 10.1074/mcp.m114.040113] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We report a novel strategy for studying synaptic pathology by concurrently measuring levels of four SNARE complex proteins from individual brain tissue samples. This method combines affinity purification and mass spectrometry and can be applied directly for studies of SNARE complex proteins in multiple species or modified to target other key elements in neuronal function. We use the technique to demonstrate altered levels of presynaptic proteins in Alzheimer disease patients and prion-infected mice.
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Affiliation(s)
- Ann Brinkmalm
- From the ‡Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, S43180 Mölndal, Sweden;
| | - Gunnar Brinkmalm
- From the ‡Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, S43180 Mölndal, Sweden
| | - William G Honer
- ¶Department of Psychiatry, University of British Columbia, Vancouver V6H3Z6, British Columbia, Canada
| | - Julie A Moreno
- ‖MRC Toxicology Unit, Hodgkin Building, University of Leicester, LE19HN Leicester, UK
| | - Joel Jakobsson
- From the ‡Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, S43180 Mölndal, Sweden
| | - Giovanna R Mallucci
- ‖MRC Toxicology Unit, Hodgkin Building, University of Leicester, LE19HN Leicester, UK
| | - Henrik Zetterberg
- From the ‡Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, S43180 Mölndal, Sweden; **UCL Institute of Neurology, Queen Square WC1N3BG, London, UK
| | - Kaj Blennow
- From the ‡Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, S43180 Mölndal, Sweden
| | - Annika Öhrfelt
- From the ‡Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, Sahlgrenska Academy at the University of Gothenburg, S43180 Mölndal, Sweden
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32
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Botulinum toxin suppression of CNS network activity in vitro. J Toxicol 2014; 2014:732913. [PMID: 24688538 PMCID: PMC3944787 DOI: 10.1155/2014/732913] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 10/22/2013] [Indexed: 11/20/2022] Open
Abstract
The botulinum toxins are potent agents which disrupt synaptic transmission. While the standard method for BoNT detection and quantification is based on the mouse lethality assay, we have examined whether alterations in cultured neuronal network activity can be used to detect the functional effects of BoNT. Murine spinal cord and frontal cortex networks cultured on substrate integrated microelectrode arrays allowed monitoring of spontaneous spike and burst activity with exposure to BoNT serotype A (BoNT-A). Exposure to BoNT-A inhibited spike activity in cultured neuronal networks where, after a delay due to toxin internalization, the rate of activity loss depended on toxin concentration. Over a 30 hr exposure to BoNT-A, the minimum concentration detected was 2 ng/mL, a level consistent with mouse lethality studies. A small proportion of spinal cord networks, but not frontal cortex networks, showed a transient increase in spike and burst activity with exposure to BoNT-A, an effect likely due to preferential inhibition of inhibitory synapses expressed in this tissue. Lastly, prior exposure to human-derived antisera containing neutralizing antibodies prevented BoNT-A induced inhibition of network spike activity. These observations suggest that the extracellular recording from cultured neuronal networks can be used to detect and quantify functional BoNT effects.
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33
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Itakura M, Tsujimura J, Yamamori S, Ohkido T, Takahashi M. NMDA receptor-dependent recruitment of calnexin to the neuronal plasma membrane. Neurosci Lett 2013; 550:173-8. [DOI: 10.1016/j.neulet.2013.06.064] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 06/12/2013] [Accepted: 06/27/2013] [Indexed: 01/18/2023]
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34
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Cox DJ, Racca C. Differential dendritic targeting of AMPA receptor subunit mRNAs in adult rat hippocampal principal neurons and interneurons. J Comp Neurol 2013; 521:1954-2007. [DOI: 10.1002/cne.23292] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 12/13/2012] [Accepted: 12/14/2012] [Indexed: 12/19/2022]
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35
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Amrutkar SD, Trier NH, Hansen PR, Houen G. Fine mapping of a monoclonal antibody to the N-Methyl D-aspartate receptor reveals a short linear epitope. Biopolymers 2013. [PMID: 23203762 DOI: 10.1002/bip.22165] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Anti-N-Methyl D-aspartate receptor encephalitis is an autoimmune disease in which autoantibodies are produced against extracellular regions of the N-Methyl D-aspartate receptor (NMDAR). In this study, we used resin-bound peptides equipped with a base labile linker to map the epitope of a monoclonal NMDAR antibody against the NMDAR NR1 subunit. The antigenicity of the synthesized resin-bound peptides was determined by enzyme-linked immunosorbent assay. Distinct reactivity was found to two extracellular overlapping peptides (amino acids, 658-687). Using N- and C-terminally truncated resin-bound peptides, the minimum functional epitope was identified as the NPSDK sequence. The peptide sequence RNPSDK (amino acids, 673-678) was identified as the complete epitope, which was found to be located in the extracellular S2 domain of the NR1 subunit. Especially, the N-terminal arginine residue was found to be essential for reactivity, whereas the remaining amino acids could be replaced with amino acids of similar side-chain functionality, indicating the importance of backbone interaction in antibody reactivity.
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Affiliation(s)
- Surekha Dipak Amrutkar
- Department of Clinical Biochemistry, Immunology and Genetics, Statens Serum Institut, Copenhagen S 2300, Denmark
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36
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Abstract
Pathological examination of dementia with Lewy bodies patients identified the presence of abnormal α-synuclein (αSyn) aggregates in the presynaptic terminals. αSyn is involved in the regulation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. Importantly, αSyn-transgenic mouse and postmortem examination of patients with Parkinson's disease have demonstrated the abnormal distribution of SNARE protein in presynaptic terminals. In this study, we investigated the effects of SNARE dysfunction on endogenous αSyn using Snap25(S187A/S187A) mutant mice. These mice have homozygous knock-in gene encoding unphosphorylatable S187A-substituted synaptosomal-associated protein of 25 kDa (SNAP-25). The mice displayed a significant age-dependent change in the distribution of αSyn and its Ser(129)-phosphorylated form in abnormally hypertrophied glutamatergic nerve terminals in the striatum. Electron-microscopic analysis revealed the abnormally condensed synaptic vesicles with concomitant mislocalization of αSyn protein to the periactive zone in the glutamatergic nerve terminals. However, the Snap25(S187A/S187A) mutant mouse harbored no abnormalities in the nigrostriatal dopaminergic neurons. Our present results suggest that SNARE dysfunction is the initial trigger of mislocalization and accumulation of αSyn, and probably is an important pathomechanism of α-synucleinopathies.
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Scullin CS, Tafoya LC, Wilson MC, Partridge LD. Presynaptic residual calcium and synaptic facilitation at hippocampal synapses of mice with altered expression of SNAP-25. Brain Res 2011; 1431:1-12. [PMID: 22119397 DOI: 10.1016/j.brainres.2011.10.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Revised: 10/19/2011] [Accepted: 10/20/2011] [Indexed: 10/15/2022]
Abstract
Paired pulse facilitation (PPF) is a form of short-term synaptic plasticity that results from an interaction of residual presynaptic Ca(2+) ([Ca(2+)](res)), number of release-competent vesicles, and the sensitivity of the vesicle release mechanisms to Ca(2+). While PPF is predominant at hippocampal Schaffer collateral-CA1 (SC-CA1) synapses, facilitation is greater in adult mice (designated Tkneo) that over express an isoform of the plasma membrane-targeted SNARE protein, SNAP-25a, which is normally predominantly expressed in juvenile animals. SNAP-25 is essential for action potential-dependent neuroexocytosis, yet the significance of the shift between the alternatively spliced variants SNAP-25a and SNAP-25b is not fully understood. This alteration of a key component of the protein machinery required for neurotransmitter release in Tkneo mice, therefore, provides a useful tool to further investigate presynaptic mechanisms that influence short-term plasticity. To explore this link between SNAP-25 and PPF, we simultaneously measured postsynaptic potentials and presynaptic [Ca(2+)](res) during paired-pulses in adult Tkneo, heterozygote null (HET), and wild type (WT) mice. We demonstrate that enhanced PPF is maintained at mature hippocampal synapses of Tkneo mice that predominantly express SNAP-25a, and that [Ca(2+)](res) kinetics are altered at synapses of Tkneo and HET mice, both of which exhibit reduced levels of total SNAP-25 expression. To evaluate the role of SNAP-25 in short-term plasticity and [Ca(2+)](res) regulation, we applied a vesicular release probability model for neurotransmission. Our results suggest that the isoform expression and total level of SNAP-25 affect both [Ca(2+)](res) dynamics and the ability of releasable vesicles to enter into a facilitated state.
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Interactions among the SNARE proteins and complexin analyzed by a yeast four-hybrid assay. Anal Biochem 2011; 416:107-11. [DOI: 10.1016/j.ab.2011.05.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Accepted: 05/06/2011] [Indexed: 11/23/2022]
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SNAP-25 contains non-acylated thiol pairs that can form intrachain disulfide bonds: possible sites for redox modulation of neurotransmission. Cell Mol Neurobiol 2011; 32:201-8. [PMID: 21850520 DOI: 10.1007/s10571-011-9748-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 07/30/2011] [Indexed: 10/17/2022]
Abstract
Intrachain disulfide bond formation among the cysteine thiols of SNAP-25, a component of the SNARE protein complex required for neurotransmitter release, has been hypothesized to link oxidative stress and inhibition of synaptic transmission. However, neither the availability in vivo of SNAP-25 thiols, which are known targets of S-palmitoylation, nor the tendency of these thiols to form intrachain disulfide bonds is known. We have examined, in rat brain extracts, both the availability of closely spaced, or vicinal, thiol pairs in SNAP-25 and the propensity of these dithiols toward disulfide bond formation using a method improved by us recently that exploits the high chemoselectivity of phenylarsine oxide (PAO) for vicinal thiols. The results show for the first time that a substantial fraction of soluble and, to a lesser extent, particulate SNAP-25 contain non-acylated PAO-binding thiol pairs and that these thiols in soluble SNAP-25 in particular have a high propensity toward disulfide bond formation. Indeed, disulfide bonds were detected in a small fraction of soluble SNAP-25 even under conditions designed to prevent or greatly limit protein thiol oxidation during experimental procedures. These results provide direct experimental support for the availability, in a subpopulation of SNAP-25, of vicinal thiols that may confer on one or more isoforms of this family of proteins a sensitivity to oxidative stress.
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Prescott GR, Chamberlain LH. Regional and developmental brain expression patterns of SNAP25 splice variants. BMC Neurosci 2011; 12:35. [PMID: 21526988 PMCID: PMC3104942 DOI: 10.1186/1471-2202-12-35] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 04/28/2011] [Indexed: 11/12/2022] Open
Abstract
Background SNAP25 is an essential SNARE protein for regulated exocytosis in neuronal cells. Differential splicing of the SNAP25 gene results in the expression of two transcripts, SNAP25a and SNAP25b. These splice variants differ by only 9 amino acids, and studies of their expression to date have been limited to analysis of the corresponding mRNAs. Although these studies have been highly informative, it is possible that factors such as differential turnover of the SNAP25 proteins could complicate interpretations based entirely on mRNA expression profiles. Results We report the generation and characterization of antibodies that distinguish between SNAP25a and SNAP25b isoforms, and their use to investigate the expression profile of these proteins in rat and human brain. In rat brain, SNAP25b protein expression increased dramatically during post-natal development, whereas the increase in SNAP25a expression was more modest and variable. The extent of this up-regulation in SNAP25b expression was similar across cortex, cerebellum and hippocampus. The SNAP25 isoforms also displayed distinct regional expression patterns, with SNAP25a very weakly expressed in both rat and human cerebellum. Quantitative analysis revealed that SNAP25b was the dominant isoform in all adult human brain regions examined. Conclusions SNAP25a and SNAP25b display distinct developmental and regional expression profiles in rat and human brain. These differences might reflect distinct functions of these highly conserved isoforms in membrane fusion pathways in the brain. The antibodies generated and characterized in this study represent important tools for future analyses of these essential SNARE protein isoforms.
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Affiliation(s)
- Gerald R Prescott
- Centre for Integrative Physiology, School of Biomedical Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
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