1
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Chen K, Garcia Padilla C, Kiselyov K, Kozai TDY. Cell-specific alterations in autophagy-lysosomal activity near the chronically implanted microelectrodes. Biomaterials 2023; 302:122316. [PMID: 37738741 PMCID: PMC10897938 DOI: 10.1016/j.biomaterials.2023.122316] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 08/22/2023] [Accepted: 09/02/2023] [Indexed: 09/24/2023]
Abstract
Intracortical microelectrodes that can record and stimulate brain activity have become a valuable technique for basic science research and clinical applications. However, long-term implantation of these microelectrodes can lead to progressive neurodegeneration in the surrounding microenvironment, characterized by elevation in disease-associated markers. Dysregulation of autophagy-lysosomal degradation, a major intracellular waste removal process, is considered a key factor in the onset and progression of neurodegenerative diseases. It is plausible that similar dysfunctions in autophagy-lysosomal degradation contribute to tissue degeneration following implantation-induced focal brain injury, ultimately impacting recording performance. To understand how the focal, persistent brain injury caused by long-term microelectrode implantation impairs autophagy-lysosomal pathway, we employed two-photon microscopy and immunohistology. This investigation focused on the spatiotemporal characterization of autophagy-lysosomal activity near the chronically implanted microelectrode. We observed an aberrant accumulation of immature autophagy vesicles near the microelectrode over the chronic implantation period. Additionally, we found deficits in autophagy-lysosomal clearance proximal to the chronic implant, which was associated with an accumulation of autophagy cargo and a reduction in lysosomal protease level during the chronic period. Furthermore, our evidence demonstrates reactive astrocytes have myelin-containing lysosomes near the microelectrode, suggesting its role of myelin engulfment during acute implantation period. Together, this study sheds light on the process of brain tissue degeneration caused by long-term microelectrode implantation, with a specific focus on impaired intracellular waste degradation.
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Affiliation(s)
- Keying Chen
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Camila Garcia Padilla
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, Pittsburgh, PA, USA
| | - Kirill Kiselyov
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Takashi D Y Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Center for Neural Basis of Cognition, Pittsburgh, PA, USA; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute of Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; NeuroTech Center, University of Pittsburgh Brain Institute, Pittsburgh, PA, USA.
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2
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de Las Heras-García L, Zabalegui I, Pampliega O. Methods to study primary cilia and autophagy in the brain. Methods Cell Biol 2023; 176:217-234. [PMID: 37164539 DOI: 10.1016/bs.mcb.2023.01.010] [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] [Indexed: 05/12/2023]
Abstract
Autophagy is an intracellular catabolic pathway that allows proteins, organelles, and pathogens to be recycled. Thus, it is crucial to maintain cell homeostasis, especially important in post-mitotic cells as neurons that cannot dilute cellular damage through mitosis. In the last decade, autophagy has been connected to the primary cilium (PC), a small organelle that acts as a sensory hub and is present in most cell types, including astrocytes and neurons. In this chapter, we briefly describe the state-of-the-art of the interplay between autophagy, PC, and its implications for the brain, in healthy and pathophysiological conditions. Deregulations in autophagy can be monitored by numerous assays, both in vivo and in vitro, and so do changes in PC length/number. Here, we relate a practical and user-friendly description of immunofluorescence methods to study autophagy and PC changes in brain slices, including the tissue preparation, confocal microscopy, image analysis, and deconvolution process.
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Affiliation(s)
- Laura de Las Heras-García
- Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain; Achucarro Basque Center for Neurosciences, Leioa, Spain
| | | | - Olatz Pampliega
- Departamento de Neurociencias, Universidad del País Vasco (UPV/EHU), Leioa, Spain; Achucarro Basque Center for Neurosciences, Leioa, Spain.
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3
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Bazzurro V, Gatta E, Angeli E, Cupello A, Lange S, Jennische E, Robello M, Diaspro A. Involvement of GABA A receptors containing α 6 subtypes in antisecretory factor activity on rat cerebellar granule cells studied by two-photon uncaging. Eur J Neurosci 2022; 56:4505-4513. [PMID: 35848658 PMCID: PMC9541628 DOI: 10.1111/ejn.15775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/11/2022] [Accepted: 07/07/2022] [Indexed: 11/28/2022]
Abstract
The antisecretory factor (AF) is an endogenous protein that counteracts intestinal hypersecretion and various inflammation conditions in vivo. It has been detected in many mammalian tissues and plasma, but its mechanisms of action are largely unknown. To study the pharmacological action of the AF on different GABAA receptor populations in cerebellar granule cells, we took advantage of the two‐photon uncaging method as this technique allows to stimulate the cell locally in well‐identified plasma membrane parts. We compared the electrophysiological response evoked by releasing a caged GABA compound on the soma, the axon initial segment and neurites before and after administering AF‐16, a 16 amino acids long peptide obtained from the amino‐terminal end of the AF protein. After the treatment with AF‐16, we observed peak current increases of varying magnitude depending on the neuronal region. Thus, studying the effects of furosemide and AF‐16 on the electrophysiological behaviour of cerebellar granules, we suggest that GABAA receptors, containing the α6 subunit, may be specifically involved in the increase of the peak current by AF, and different receptor subtype distribution may be responsible for differences in this increase on the cell.
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Affiliation(s)
- Virginia Bazzurro
- DIFILAB, Department of Physics, University of Genoa, Genoa, Italy.,Nanoscopy, CHT Erzelli, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Elena Gatta
- DIFILAB, Department of Physics, University of Genoa, Genoa, Italy
| | - Elena Angeli
- DIFILAB, Department of Physics, University of Genoa, Genoa, Italy
| | - Aroldo Cupello
- DIFILAB, Department of Physics, University of Genoa, Genoa, Italy
| | - Stefan Lange
- Department of Infectious Diseases, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.,Region Västra Götaland, Department of Clinical Microbiology, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Eva Jennische
- Department of Medical Biochemistry and Cell Biology, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Mauro Robello
- DIFILAB, Department of Physics, University of Genoa, Genoa, Italy
| | - Alberto Diaspro
- DIFILAB, Department of Physics, University of Genoa, Genoa, Italy.,Nanoscopy, CHT Erzelli, Istituto Italiano di Tecnologia, Genoa, Italy
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4
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Suzuki A, Iwaya C, Ogata K, Yoshioka H, Shim J, Tanida I, Komatsu M, Tada N, Iwata J. Impaired GATE16-mediated exocytosis in exocrine tissues causes Sjögren's syndrome-like exocrinopathy. Cell Mol Life Sci 2022; 79:307. [PMID: 35593968 PMCID: PMC11071900 DOI: 10.1007/s00018-022-04334-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 11/03/2022]
Abstract
Sjögren's syndrome (SjS) is a chronic autoimmune disease characterized by immune cell infiltration of the exocrine glands, mainly the salivary and lacrimal glands. Despite recent advances in the clinical and mechanistic characterization of the disease, its etiology remains largely unknown. Here, we report that mice with a deficiency for either Atg7 or Atg3, which are enzymes involved in the ubiquitin modification pathway, in the salivary glands exhibit a SjS-like phenotype, characterized by immune cell infiltration with autoantibody detection, acinar cell death, and dry mouth. Prior to the onset of the SjS-like phenotype in these null mice, we detected an accumulation of secretory vesicles in the acinar cells of the salivary glands and found that GATE16, an uncharacterized autophagy-related molecule activated by ATG7 (E1-like enzyme) and ATG3 (E2-like enzyme), was highly expressed in these cells. Notably, GATE16 was activated by isoproterenol, an exocytosis inducer, and localized on the secretory vesicles in the acinar cells of the salivary glands. Failure to activate GATE16 was correlated with exocytosis defects in the acinar cells of the salivary glands in Atg7 and Atg3 cKO mice. Taken together, our results show that GATE16 activation regulated by the autophagic machinery is crucial for exocytosis and that defects in this pathway cause SjS.
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Affiliation(s)
- Akiko Suzuki
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
- Center for Craniofacial Research, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Chihiro Iwaya
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
- Center for Craniofacial Research, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Kenichi Ogata
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
- Center for Craniofacial Research, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Hiroki Yoshioka
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
- Center for Craniofacial Research, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Junbo Shim
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
- Center for Craniofacial Research, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA
| | - Isei Tanida
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Tokyo, 113-8431, Japan
| | - Masaaki Komatsu
- Department of Organ and Cell Physiology, Juntendo University Graduate School of Medicine, Tokyo, 113-8431, Japan
| | - Norihiro Tada
- Division of Genome Research, Research Institute for Diseases of Old Ages, Juntendo University School of Medicine, Tokyo, 113-8431, Japan
| | - Junichi Iwata
- Department of Diagnostic & Biomedical Sciences, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA.
- Center for Craniofacial Research, School of Dentistry, The University of Texas Health Science Center at Houston, Houston, TX, 77054, USA.
- Pediatric Research Center, School of Medicine, The University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
- MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston, TX, 77030, USA.
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5
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Guo X, Wu Z. GABARAP ameliorates IL-1β-induced inflammatory responses and osteogenic differentiation in bone marrow-derived stromal cells by activating autophagy. Sci Rep 2021; 11:11561. [PMID: 34078931 PMCID: PMC8172545 DOI: 10.1038/s41598-021-90586-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/13/2021] [Indexed: 12/13/2022] Open
Abstract
Bone mesenchymal stem cells (BMSCs) are the most commonly investigated progenitor cells in bone defect repair and osteoarthritis subchondral bone regeneration; however, these studies are limited by complex inflammatory conditions. In this study, we investigated whether pro-autophagic γ-aminobutyric acid receptor-associated protein (GABARAP) promotes BMSCs proliferation and osteogenic differentiation by modulating autophagy in the presence or absence of interleukin-1 beta (IL-1β) in vitro. The expression levels of all relevant factors were evaluated by qRT-PCR or western blotting where appropriate. BMSCs differentiation were assessed by Alizarin Red, alkaline phosphatase, safranin O, and Oil Red O staining. Furthermore, the interactions between autophagy and osteogenic differentiation were investigated by co-treatment with the autophagy inhibitor 3-methyladenine (3-MA). As the results, we found that treatment with recombinant human His6-GABARAP protein promoted cell proliferation, inhibited apoptosis, and reduced ROS generation by increasing autophagic activity, particularly when co-cultured with IL-1β. Moreover, His6-GABARAP could effectively increase the osteogenic differentiation of BMSCs. The expression levels of inflammatory factors were significantly decreased by His6-GABARAP treatment, whereas its protective effects were attenuated by 3-MA. This study demonstrates that GABARAP maintains BMSCs survival and strengthens their osteogenic differentiation in an inflammatory environment by upregulating mediators of the autophagy pathway.
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Affiliation(s)
- Xiaobo Guo
- Department of Orthopedics, Jincheng General Hospital, Jincheng, 048000, China.
| | - Zhenyuan Wu
- Department of Orthopedics, Jincheng General Hospital, Jincheng, 048000, China
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6
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McMillan P, Wheeler J, Gatlin RE, Taylor L, Strovas T, Baum M, Bird TD, Latimer C, Keene CD, Kraemer BC, Liachko NF. Adult onset pan-neuronal human tau tubulin kinase 1 expression causes severe cerebellar neurodegeneration in mice. Acta Neuropathol Commun 2020; 8:200. [PMID: 33228809 PMCID: PMC7684928 DOI: 10.1186/s40478-020-01073-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/07/2020] [Indexed: 12/18/2022] Open
Abstract
The kinase TTBK1 is predominantly expressed in the central nervous system and has been implicated in neurodegenerative diseases including Alzheimer’s disease, frontotemporal lobar degeneration, and amyotrophic lateral sclerosis through its ability to phosphorylate the proteins tau and TDP-43. Mutations in the closely related gene TTBK2 cause spinocerebellar ataxia, type 11. However, it remains unknown whether altered TTBK1 activity alone can drive neurodegeneration. In order to characterize the consequences of neuronal TTBK1 upregulation in adult brains, we have generated a transgenic mouse model with inducible pan-neuronal expression of human TTBK1. We find that these inducible TTBK1 transgenic mice (iTTBK1 Tg) exhibit motor and cognitive phenotypes, including decreased grip strength, hyperactivity, limb-clasping, and spatial memory impairment. These behavioral phenotypes occur in conjunction with progressive weight loss, neuroinflammation, and severe cerebellar degeneration with Purkinje neuron loss. Phenotype onset begins weeks after TTBK1 induction, culminating in average mortality around 7 weeks post induction. The iTTBK1 Tg animals lack any obvious accumulation of pathological tau or TDP-43, indicating that TTBK1 expression drives neurodegeneration in the absence of detectable pathological protein deposition. In exploring TTBK1 functions, we identified the autophagy related protein GABARAP to be a novel interacting partner of TTBK1 and show that GABARAP protein levels increase in the brain following induction of TTBK1. These iTTBK1 Tg mice exhibit phenotypes reminiscent of spinocerebellar ataxia, and represent a new model of cerebellar neurodegeneration.
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7
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Wu Z, Lu H, Yao J, Zhang X, Huang Y, Ma S, Zou K, Wei Y, Yang Z, Li J, Zhao J. GABARAP promotes bone marrow mesenchymal stem cells-based the osteoarthritis cartilage regeneration through the inhibition of PI3K/AKT/mTOR signaling pathway. J Cell Physiol 2019; 234:21014-21026. [PMID: 31020644 DOI: 10.1002/jcp.28705] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 04/02/2019] [Accepted: 04/10/2019] [Indexed: 12/16/2022]
Abstract
Osteoarthritis (OA) is a degenerative disease of the cartilage prevalent in the middle-aged and elderly demographic. Direct transplantation of bone marrow mesenchymal stem cells (BMSCs) or stem cell-derived chondrocytes into the damaged cartilage is a promising therapeutic strategy for OA, but is limited by the poor survival and in situ stability of the chondrocytes. Autophagy is a unique catabolic pathway conserved across eukaryotes that maintains cellular homeostasis, recycles damaged proteins and organelles, and promotes survival. The aim of this study was to determine the role of the proautophagic γ-aminobutyric acid receptor-associated protein (GABARAP) on the therapeutic effects of BMSCs-derived chondrocytes in a rat model of OA, and elucidate the underlying mechanisms. Anterior cruciate ligament transection (ACLT) was performed in Sprague-Dawley rats to simulate OA, and the animals were injected weekly with recombinant human His6-GABARAP protein, BMSCs-derived differentiated chondrocytes (DCs) or their combination directly into the knee cartilage. The regenerative effects of GABARAP and/or DCs were determined in term of International Cartilage Repair Society scores and cartilage thickness. The combination treatment of DCs and GABARAP significantly increased the levels of the ECM proteins Col II and SOX9, indicating formation of hyaline-like cartilage, and decreased chondrocyte apoptosis and inflammation. DCs + GABARAP treatment also upregulated the mediators of the autophagy pathway and suppressed the PI3K/AKT/mTOR pathway, indicating a mechanistic basis of its therapeutic action.
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Affiliation(s)
- Zhengyuan Wu
- Department of Orthopaedics Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Huiping Lu
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jun Yao
- Department of Bone and Joint Surgery, The First Affliated Hospital of Guangxi Medical University, Nanning, China
| | - Xiaohan Zhang
- Department of Orthopaedics Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Yimei Huang
- Department of Orthopaedics Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Shiting Ma
- Department of Orthopaedics Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Kai Zou
- Department of Orthopaedics Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Yan Wei
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Zhengyi Yang
- Department of Orthopaedics Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jia Li
- Department of Pathology, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Jinmin Zhao
- Department of Orthopaedics Trauma and Hand Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
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8
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Jeon P, Park JH, Jun YW, Lee YK, Jang DJ, Lee JA. Development of GABARAP family protein-sensitive LIR-based probes for neuronal autophagy. Mol Brain 2019; 12:33. [PMID: 30961647 PMCID: PMC6454701 DOI: 10.1186/s13041-019-0458-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 04/01/2019] [Indexed: 11/10/2022] Open
Abstract
Autophagy allows for lysosomal cellular degradation of cytosolic components. In particular, neuronal autophagy is essential for cellular homeostasis and neuronal survival and is tightly regulated by several autophagy-related (ATG) proteins in post-mitotic neurons. Among these ATG proteins, the LC3/GABARAP proteins are known to regulate autophagosome biogenesis/maturation and cargo recognition. However, little is known about the role of GABARAP family proteins in neuronal autophagy despite their abundant expression in post-mitotic neurons. We have previously developed HyD (Hydrophobic Domain)-LIR (LC3-interacting region)-based autophagosome markers. In this study, to monitor GABARAP family proteins in autophagosomes of post-mitotic neurons, we improved the sensitivity of the probes for specifically detecting endogenous GABARAP family proteins by adding one more LIR motif to the LIR probes. We have tested the efficiency of two different LIRs, from ULK2 and Stbd1, in regard to their cellular localization to autophagosomes. HyD-2xLIR(ULK2)-GFP and HyD-2xLIR(Stbd1)-GFP demonstrated specific localization to GABARAP-positive autophagosomes relative to LC3B-positive autophagosomes in MEF/HeLa cells in an autophagy-dependent manner. Indeed, HyD-2xLIR(Stbd1)-GFP could efficiently detect GABARAP-positive autophagosomes in cultured cortical neurons. Our improved GABARAP-sensitive probes will contribute toward understanding the specific role of GABARAP family proteins in regard to neuronal autophagy.
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Affiliation(s)
- Pureum Jeon
- Department of Biological Sciences and Biotechnology, College of Life Sciences and Nanotechnology, Hannam University, 461-6 Jeonmin-dong, Yuseong-gu, Daejeon, 34054, Republic of Korea
| | - Ju-Hui Park
- Department of Ecological Science, College of Ecology and Environment, Kyungpook National University, 386, Gajang-dong, Sangju-si, Kyungbuk, 37224, South Korea
| | - Yong-Woo Jun
- Department of Ecological Science, College of Ecology and Environment, Kyungpook National University, 386, Gajang-dong, Sangju-si, Kyungbuk, 37224, South Korea
| | - You-Kyung Lee
- Department of Biological Sciences and Biotechnology, College of Life Sciences and Nanotechnology, Hannam University, 461-6 Jeonmin-dong, Yuseong-gu, Daejeon, 34054, Republic of Korea
| | - Deok-Jin Jang
- Department of Ecological Science, College of Ecology and Environment, Kyungpook National University, 386, Gajang-dong, Sangju-si, Kyungbuk, 37224, South Korea.
| | - Jin-A Lee
- Department of Biological Sciences and Biotechnology, College of Life Sciences and Nanotechnology, Hannam University, 461-6 Jeonmin-dong, Yuseong-gu, Daejeon, 34054, Republic of Korea.
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9
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Fan J, Li D, Chen HS, Huang JG, Xu JF, Zhu WW, Chen JG, Wang F. Metformin produces anxiolytic-like effects in rats by facilitating GABA A receptor trafficking to membrane. Br J Pharmacol 2018; 176:297-316. [PMID: 30318707 DOI: 10.1111/bph.14519] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 09/15/2018] [Accepted: 09/19/2018] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE Altered function or expression of GABAA receptors contributes to anxiety disorders. Benzodiazepines are widely prescribed for the treatment of anxiety. However, the long-term use of benzodiazepines increases the risk of developing drug dependence and tolerance. Thus, it is urgent to explore new therapeutic approaches. Metformin is widely used to treat Type 2 diabetes and other metabolic syndromes. However, the role of metformin in psychiatric disorders, especially anxiety, remains largely unknown. EXPERIMENTAL APPROACH We examined the effects of metformin on anxiety-like behaviour of rats in open field test and elevated plus maze test. We also observed the effect of metformin (10 μM, in vitro; 100 mg·kg-1 , in vivo) on the trafficking of GABAA receptors, as mechanisms underlying the anxiolytic effects of metformin. KEY RESULTS Metformin (100 mg·kg-1 , i.p. 30 min) displayed a robust and rapid anxiolytic effect, without tolerance. Metformin up-regulated the surface expression of GABAA receptors and increased miniature inhibitory postsynaptic currents (mIPSCs). AMP-activated protein kinase (AMPK) activated by metformin-induced stimulation of forkhead box O3a (FoxO3a) transcriptional activity, followed by increased expression of GABAA receptor-associated protein (GABARAP) and its binding to GABAA receptors finally resulted in the membrane insertion of GABAA receptors. CONCLUSIONS AND IMPLICATIONS Metformin increased mIPSCs by up-regulating the membrane insertion of GABAA receptors, via a pathway involving AMPK, FoxO3a, and the GABAA receptor-associated protein. Thus metformin has a potential new use in the treatment of anxiety disorders.
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Affiliation(s)
- Jun Fan
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Di Li
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong-Sheng Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Geng Huang
- Department of Pharmaceutics, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jun-Feng Xu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wen-Wen Zhu
- Department of Pharmaceutics, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Guo Chen
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,The Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, China.,Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation (HUST), Wuhan, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China.,The Collaborative-Innovation Center for Brain Science, Wuhan, China
| | - Fang Wang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,The Key Laboratory of Neurological Diseases (HUST), Ministry of Education of China, Wuhan, China.,Hubei Key Laboratory of Drug Target Research and Pharmacodynamic Evaluation (HUST), Wuhan, China.,Laboratory of Neuropsychiatric Diseases, The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan, China.,The Collaborative-Innovation Center for Brain Science, Wuhan, China
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10
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Annamneedi A, Caliskan G, Müller S, Montag D, Budinger E, Angenstein F, Fejtova A, Tischmeyer W, Gundelfinger ED, Stork O. Ablation of the presynaptic organizer Bassoon in excitatory neurons retards dentate gyrus maturation and enhances learning performance. Brain Struct Funct 2018; 223:3423-3445. [PMID: 29915867 PMCID: PMC6132633 DOI: 10.1007/s00429-018-1692-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 05/30/2018] [Indexed: 01/05/2023]
Abstract
Bassoon is a large scaffolding protein of the presynaptic active zone involved in the development of presynaptic terminals and in the regulation of neurotransmitter release at both excitatory and inhibitory brain synapses. Mice with constitutive ablation of the Bassoon (Bsn) gene display impaired presynaptic function, show sensory deficits and develop severe seizures. To specifically study the role of Bassoon at excitatory forebrain synapses and its relevance for control of behavior, we generated conditional knockout (Bsn cKO) mice by gene ablation through an Emx1 promoter-driven Cre recombinase. In these animals, we confirm selective loss of Bassoon from glutamatergic neurons of the forebrain. Behavioral assessment revealed that, in comparison to wild-type littermates, Bsn cKO mice display selectively enhanced contextual fear memory and increased novelty preference in a spatial discrimination/pattern separation task. These changes are accompanied by an augmentation of baseline synaptic transmission at medial perforant path to dentate gyrus (DG) synapses, as indicated by increased ratios of field excitatory postsynaptic potential slope to fiber volley amplitude. At the structural level, an increased complexity of apical dendrites of DG granule cells can be detected in Bsn cKO mice. In addition, alterations in the expression of cellular maturation markers and a lack of age-dependent decrease in excitability between juvenile and adult Bsn cKO mice are observed. Our data suggest that expression of Bassoon in excitatory forebrain neurons is required for the normal maturation of the DG and important for spatial and contextual memory.
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Affiliation(s)
- Anil Annamneedi
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Gürsel Caliskan
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Sabrina Müller
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Dirk Montag
- Neurogenetics Laboratory, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Eike Budinger
- Department of Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Frank Angenstein
- Special Laboratory Noninvasive Brain Imaging, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- Functional Neuroimaging Group, German Center for Neurodegenerative Diseases, Magdeburg, Germany
| | - Anna Fejtova
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
- RG Presynaptic Plasticity, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany
| | - Wolfgang Tischmeyer
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- Special Laboratory Molecular Biological Techniques, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Eckart D. Gundelfinger
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
- Molecular Neuroscience, Medical School, Otto von Guericke University, Magdeburg, Germany
| | - Oliver Stork
- Department of Genetics and Molecular Neurobiology, Institute of Biology, Otto-von-Guericke-University, Magdeburg, Germany
- Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
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Assessment of Autophagy in Neurons and Brain Tissue. Cells 2017; 6:cells6030025. [PMID: 28832529 PMCID: PMC5617971 DOI: 10.3390/cells6030025] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 08/01/2017] [Accepted: 08/21/2017] [Indexed: 12/31/2022] Open
Abstract
Autophagy is a complex process that controls the transport of cytoplasmic components into lysosomes for degradation. This highly conserved proteolytic system involves dynamic and complex processes, using similar molecular elements and machinery from yeast to humans. Moreover, autophagic dysfunction may contribute to a broad spectrum of mammalian diseases. Indeed, in adult tissues, where the capacity for regeneration or cell division is low or absent (e.g., in the mammalian brain), the accumulation of proteins/peptides that would otherwise be recycled or destroyed may have pathological implications. Indeed, such changes are hallmarks of pathologies, like Alzheimer’s, Prion or Parkinson’s disease, known as proteinopathies. However, it is still unclear whether such dysfunction is a cause or an effect in these conditions. One advantage when analysing autophagy in the mammalian brain is that almost all the markers described in different cell lineages and systems appear to be present in the brain, and even in neurons. By contrast, the mixture of cell types present in the brain and the differentiation stage of such neurons, when compared with neurons in culture, make translating basic research to the clinic less straightforward. Thus, the purpose of this review is to describe and discuss the methods available to monitor autophagy in neurons and in the mammalian brain, a process that is not yet fully understood, focusing primarily on mammalian macroautophagy. We will describe some general features of neuronal autophagy that point to our focus on neuropathologies in which macroautophagy may be altered. Indeed, we centre this review around the hypothesis that enhanced autophagy may be able to provide therapeutic benefits in some brain pathologies, like Alzheimer’s disease, considering this pathology as one of the most prevalent proteinopathies.
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Purkinje Cells Are More Vulnerable to the Specific Depletion of Cathepsin D Than to That of Atg7. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:1586-1600. [PMID: 28502476 DOI: 10.1016/j.ajpath.2017.02.020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 02/27/2017] [Indexed: 12/24/2022]
Abstract
Neurologic phenotypes of cathepsin D (CTSD)-deficient mice, a murine model of neuronal ceroid lipofuscinoses, indicate the importance of CTSD for the maintenance of metabolism in central nervous system neurons. To further understand the role of CTSD in central nervous system neurons, we generated mice with a CTSD deficiency specifically in the Purkinje cells (PCs) (CTSDFlox/Flox;GRID2-Cre) and compared their phenotypes with those of PC-selective Atg7-deficient (Atg7Flox/Flox;GRID2-Cre) mice. In both strains of mice, PCs underwent degeneration, but the CTSD-deficient PCs disappeared more rapidly than their Atg7-deficient counterparts. When CTSD-deficient PCs died, the neuronal cell bodies became shrunken, filled with autophagosomes and autolysosomes, and had nuclei with dispersed small chromatin fragments. The dying Atg7-deficient PCs also showed similar ultrastructures, indicating that the neuronal cell death of CTSD- and Atg7-deficient PCs was distinct from apoptosis. Immunohistochemical observations showed the formation of calbindin-positive axonal spheroids and the swelling of vesicular GABA transporter-positive presynaptic terminals that were more pronounced in Atg7-deficient PCs than in CTSD-deficient PCs. An accumulation of tubular vesicles may have derived from the smooth endoplasmic reticulum; nascent autophagosome-like structures with double membranes was a common feature in the swollen axons of these PCs. These results suggested that PCs were more vulnerable to CTSD deficiency in lysosomes than to autophagy impairment, and this vulnerability does not depend on the severity of axonal swelling.
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Randhawa R, Sehgal M, Singh TR, Duseja A, Changotra H. Unc-51 like kinase 1 (ULK1) in silico analysis for biomarker identification: a vital component of autophagy. Gene 2015; 562:40-9. [PMID: 25701603 DOI: 10.1016/j.gene.2015.02.056] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2014] [Revised: 02/03/2015] [Accepted: 02/05/2015] [Indexed: 12/31/2022]
Abstract
Autophagy is a degradation pathway involving lysosomal machinery for degradation of damaged organelles like the endoplasmic reticulum and mitochondria into their building blocks to maintain homeostasis within the cell. ULK1, a serine/threonine kinase, is conserved across species, from yeasts to mammals, and plays a central role in autophagy pathway. It receives signals from upstream modulators such as TIP60, mTOR and AMPK and relays them to its downstream substrates like Ambra1 and ZIP kinase. The activity of this complex is regulated through protein-protein interactions and post-translational modifications. Applying in silico analysis we identified (i) conserved patterns of ULK1 that showed its evolutionary relationship between the species which were closely related in a family compared to others. (ii) A total of 23 TFBS distributed throughout ULK1 and nuclear factor (erythroid-derived) 2 (NFE2) is of utmost significance because of its high importance rate. NEF2 has already been shown experimentally to play a role in the autophagy pathway. Most of these were of zinc coordinating class and we suggest that this information could be utilized to modulate this pathway by modifying interactions of these TFs with ULK1. (iii) CATTT haplotype was prominently found with frequency 0.774 in the studied population and nsSNPs which could have harmful effect on ULK1 protein and these could further be tested. (iv) A total of 83 phosphorylation sites were identified; 26 are already known and 57 are new that include one at tyrosine residue which could further be studied for its involvement in ULK1 regulation and hence autophagy. Furthermore, 4 palmitoylation sites at positions 426, 927, 1003 and 1049 were also found which could further be studied for protein-protein interactions as well as in trafficking.
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Affiliation(s)
- Rohit Randhawa
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan 1732 34 Himachal Pradesh, India
| | - Manika Sehgal
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan 1732 34 Himachal Pradesh, India
| | - Tiratha Raj Singh
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan 1732 34 Himachal Pradesh, India
| | - Ajay Duseja
- Department of Hepatology, Postgraduate Institute of Medical Education and Research, Chandigarh 160 012, India
| | - Harish Changotra
- Department of Biotechnology and Bioinformatics, Jaypee University of Information Technology, Waknaghat, Solan 1732 34 Himachal Pradesh, India.
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Tanida I, Ueno T, Kominami E. In vitro assays of lipidation of Mammalian Atg8 homologs. CURRENT PROTOCOLS IN CELL BIOLOGY 2014; 64:11.20.1-13. [PMID: 25181299 DOI: 10.1002/0471143030.cb1120s64] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Atg8 modifier in yeast is conjugated to phosphatidylethanolamine via ubiquitylation-like reactions essential for autophagy. Mammalian Atg8 homologs (Atg8s) including LC3, GABARAP, and GATE-16, are also ubiquitin-like modifiers. The carboxyl termini of mammalian Atg8 homologs are cleaved by Atg4B, a cysteine protease, to expose carboxyl terminal Gly which is essential for this ubiquitylation-like reaction. Thereafter, the Atg8 homologs are activated by Atg7, an E1-like enzyme, to form unstable Atg7-Atg8 E1-substrate intermediates via a thioester bond. The activated Atg8 homologs are transferred to mammalian Atg3, an E2-like enzyme, to form unstable Atg3-Atg8 E2-substrate intermediates via a thioester bond. Finally, Atg8 homologs are conjugated to phospholipids, phosphatidylethanolamine, and phosphatidylserine. Here, we describe a protocol for the reconstituted conjugation systems for mammalian Atg8 homologs in vitro using purified recombinant Atg proteins and liposomes.
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Affiliation(s)
- Isei Tanida
- Department of Cell Biology and Biochemistry, National Institute of Infectious Diseases, Tokyo, Japan; Laboratory of Proteomics and Biomolecular Science, Juntendo University Graduate School of Medicine, Tokyo, Japan
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Suyama M, Koike M, Asaoka D, Mori H, Oguro M, Ueno T, Nagahara A, Watanabe S, Uchiyama Y. Increased immunoreactivity of cathepsins in the rat esophagus under chronic acid reflux esophagitis. J Histochem Cytochem 2014; 62:645-60. [PMID: 24943348 DOI: 10.1369/0022155414542300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We have designed a stable rat chronic acid reflux esophagitis (RE) model. In gastrointestinal lesions, several lysosomal cathepsins are known to participate in epithelial permeability in cell-cell connections, such as tight junctions in ulcerative colitis. However, very few studies have focused on the distribution of cathepsins in the esophageal multilayer squamous epithelium. Therefore to clarify the role of cathepsins in RE, we investigated their immunohistological localization in the esophageal epithelium under normal conditions and after RE. Of the cathepsins examined (cathepsins B, C, D, F, H, L, S, and X), granular immunoreactivity for cathepsins B, C, D and L was observed in the control esophageal epithelia; although, their distribution differed depending on the enzyme examined. In the RE model, immunoreactivity of these cathepsins was increased in esophageal epithelial cells and activated macrophages. The immunoreactivity for cathepsins F, H, S and X was barely detectable in the control esophageal epithelium. However, in the RE model, we noticed a slight increase in the expression of cathepsins H and X in the epithelial cells. Furthermore, activated macrophages of the RE model possessed intense immunoreactivity for these cathepsins, which may have been related to esophageal inflammatory mechanisms.
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Affiliation(s)
- Masayuki Suyama
- Department of Gastroenterology (MS, DA, HM, MO, AN, SW), Juntendo University School of Medicine, Tokyo, JapanDepartment of Cell Biology and Neuroscience (MK,YU), Juntendo University School of Medicine, Tokyo, JapanCenter for Biomedical Research Resources (TU), Juntendo University Graduate School of Medicine, Tokyo, JapanDepartment of Cellular and Molecular Neuropathology (YU), Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Masato Koike
- Department of Gastroenterology (MS, DA, HM, MO, AN, SW), Juntendo University School of Medicine, Tokyo, JapanDepartment of Cell Biology and Neuroscience (MK,YU), Juntendo University School of Medicine, Tokyo, JapanCenter for Biomedical Research Resources (TU), Juntendo University Graduate School of Medicine, Tokyo, JapanDepartment of Cellular and Molecular Neuropathology (YU), Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Daisuke Asaoka
- Department of Gastroenterology (MS, DA, HM, MO, AN, SW), Juntendo University School of Medicine, Tokyo, JapanDepartment of Cell Biology and Neuroscience (MK,YU), Juntendo University School of Medicine, Tokyo, JapanCenter for Biomedical Research Resources (TU), Juntendo University Graduate School of Medicine, Tokyo, JapanDepartment of Cellular and Molecular Neuropathology (YU), Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hiroki Mori
- Department of Gastroenterology (MS, DA, HM, MO, AN, SW), Juntendo University School of Medicine, Tokyo, JapanDepartment of Cell Biology and Neuroscience (MK,YU), Juntendo University School of Medicine, Tokyo, JapanCenter for Biomedical Research Resources (TU), Juntendo University Graduate School of Medicine, Tokyo, JapanDepartment of Cellular and Molecular Neuropathology (YU), Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Masako Oguro
- Department of Gastroenterology (MS, DA, HM, MO, AN, SW), Juntendo University School of Medicine, Tokyo, JapanDepartment of Cell Biology and Neuroscience (MK,YU), Juntendo University School of Medicine, Tokyo, JapanCenter for Biomedical Research Resources (TU), Juntendo University Graduate School of Medicine, Tokyo, JapanDepartment of Cellular and Molecular Neuropathology (YU), Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takashi Ueno
- Department of Gastroenterology (MS, DA, HM, MO, AN, SW), Juntendo University School of Medicine, Tokyo, JapanDepartment of Cell Biology and Neuroscience (MK,YU), Juntendo University School of Medicine, Tokyo, JapanCenter for Biomedical Research Resources (TU), Juntendo University Graduate School of Medicine, Tokyo, JapanDepartment of Cellular and Molecular Neuropathology (YU), Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Akihito Nagahara
- Department of Gastroenterology (MS, DA, HM, MO, AN, SW), Juntendo University School of Medicine, Tokyo, JapanDepartment of Cell Biology and Neuroscience (MK,YU), Juntendo University School of Medicine, Tokyo, JapanCenter for Biomedical Research Resources (TU), Juntendo University Graduate School of Medicine, Tokyo, JapanDepartment of Cellular and Molecular Neuropathology (YU), Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Sumio Watanabe
- Department of Gastroenterology (MS, DA, HM, MO, AN, SW), Juntendo University School of Medicine, Tokyo, JapanDepartment of Cell Biology and Neuroscience (MK,YU), Juntendo University School of Medicine, Tokyo, JapanCenter for Biomedical Research Resources (TU), Juntendo University Graduate School of Medicine, Tokyo, JapanDepartment of Cellular and Molecular Neuropathology (YU), Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yasuo Uchiyama
- Department of Gastroenterology (MS, DA, HM, MO, AN, SW), Juntendo University School of Medicine, Tokyo, JapanDepartment of Cell Biology and Neuroscience (MK,YU), Juntendo University School of Medicine, Tokyo, JapanCenter for Biomedical Research Resources (TU), Juntendo University Graduate School of Medicine, Tokyo, JapanDepartment of Cellular and Molecular Neuropathology (YU), Juntendo University Graduate School of Medicine, Tokyo, Japan
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