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Bame M, McInnis MG, O'Shea KS. MicroRNA Alterations in Induced Pluripotent Stem Cell-Derived Neurons from Bipolar Disorder Patients: Pathways Involved in Neuronal Differentiation, Axon Guidance, and Plasticity. Stem Cells Dev 2020; 29:1145-1159. [PMID: 32438891 PMCID: PMC7469698 DOI: 10.1089/scd.2020.0046] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Accepted: 05/21/2020] [Indexed: 12/17/2022] Open
Abstract
Bipolar disorder (BP) is a complex psychiatric condition characterized by severe fluctuations in mood for which underlying pathological mechanisms remain unclear. Family and twin studies have identified a hereditary component to the disorder, but a single causative gene (or set of genes) has not been identified. MicroRNAs (miRNAs) are small, noncoding RNAs ∼20 nucleotides in length, that are responsible for the posttranslational regulation of multiple genes. They have been shown to play important roles in neural development as well as in the adult brain, and several miRNAs have been reported to be dysregulated in postmortem brain tissue isolated from bipolar patients. Because there are no viable cellular models to study BP, we have taken advantage of the recent discovery that somatic cells can be reprogrammed to pluripotency then directed to form the full complement of neural cells. Analysis of RNAs extracted from Control and BP patient-derived neurons identified 58 miRNAs that were differentially expressed between the two groups. Using quantitative polymerase chain reaction we validated six miRNAs that were elevated and two miRNAs that were expressed at lower levels in BP-derived neurons. Analysis of the targets of the miRNAs indicate that they may regulate a number of cellular pathways, including axon guidance, Mapk, Ras, Hippo, Neurotrophin, and Wnt signaling. Many are involved in processes previously implicated in BP, such as cell migration, axon guidance, dendrite and synapse development, and function. We have validated targets of several different miRNAs, including AXIN2, BDNF, RELN, and ANK3 as direct targets of differentially expressed miRNAs using luciferase assays. Identification of pathways altered in patient-derived neurons suggests that disruption of these regulatory networks that may contribute to the complex phenotypes in BP.
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Affiliation(s)
- Monica Bame
- Department of Psychiatry, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Melvin G. McInnis
- Department of Psychiatry, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - K. Sue O'Shea
- Department of Psychiatry, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Abstract
Apicomplexan protozoan parasites, such as those causing malaria and toxoplasmosis, must invade the cells of their hosts in order to establish a pathogenic infection. Timely release of proteins from a series of apical organelles is required for invasion. Neither the vesicular fusion events that underlie secretion nor the observed reliance of the various processes on changes in intracellular calcium concentrations is completely understood. We identified a group of three proteins with strong homology to the calcium-sensing ferlin family, which are known to be involved in protein secretion in other organisms. Surprisingly, decreasing the amounts of one of these proteins (TgFER2) did not have any effect on the typically calcium-dependent steps in invasion. Instead, TgFER2 was essential for the release of proteins from organelles called rhoptries. These data provide a tantalizing first look at the mechanisms controlling the very poorly understood process of rhoptry secretion, which is essential for the parasite’s infection cycle. Invasion of host cells by apicomplexan parasites such as Toxoplasma gondii is critical for their infectivity and pathogenesis. In Toxoplasma, secretion of essential egress, motility, and invasion-related proteins from microneme organelles is regulated by oscillations of intracellular Ca2+. Later stages of invasion are considered Ca2+ independent, including the secretion of proteins required for host cell entry and remodeling from the parasite’s rhoptries. We identified a family of three Toxoplasma proteins with homology to the ferlin family of double C2 domain-containing Ca2+ sensors. In humans and model organisms, such Ca2+ sensors orchestrate Ca2+-dependent exocytic membrane fusion with the plasma membrane. Here we focus on one ferlin that is conserved across the Apicomplexa, T. gondii FER2 (TgFER2). Unexpectedly, conditionally TgFER2-depleted parasites secreted their micronemes normally and were completely motile. However, these parasites were unable to invade host cells and were therefore not viable. Knockdown of TgFER2 prevented rhoptry secretion, and these parasites failed to form the moving junction at the parasite-host interface necessary for host cell invasion. Collectively, these data demonstrate the requirement of TgFER2 for rhoptry secretion in Toxoplasma tachyzoites and suggest a possible Ca2+ dependence of rhoptry secretion. These findings provide the first mechanistic insights into this critical yet poorly understood aspect of apicomplexan host cell invasion.
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Du C, Wang Y, Zhang F, Yan S, Guan Y, Gong X, Zhang T, Cui X, Wang X, Zhang CX. Synaptotagmin-11 inhibits cytokine secretion and phagocytosis in microglia. Glia 2017; 65:1656-1667. [PMID: 28686317 DOI: 10.1002/glia.23186] [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: 01/19/2017] [Revised: 05/18/2017] [Accepted: 06/20/2017] [Indexed: 12/18/2022]
Abstract
Cytokine secretion and phagocytosis are key functions of activated microglia. However, the molecular mechanisms underlying their regulation in microglia remain largely unknown. Here, we report that synaptotagmin-11 (Syt11), a non-Ca2+ -binding Syt implicated in Parkinson disease and schizophrenia, inhibits cytokine secretion and phagocytosis in microglia. We found Syt11 expression in microglia in brain slices and primary microglia. Interestingly, Syt11-knockdown (KD) increased cytokine secretion and NO release in primary microglia both in the absence and presence of lipopolysaccharide. NF-κB was activated in untreated KD microglia together with enhanced synthesis of IL-6, TNF-α, IL-1β, and iNOS. When the release capacity was assessed by the ratio of extracellular to intracellular levels, only the IL-6 and TNF-α secretion capacity was increased in Syt11-KD cells, suggesting that Syt11 specifically regulates conventional secretion. Consistently, Syt11 localized to the trans-Golgi network and recycling endosomes. In addition, Syt11 was recruited to phagosomes and its deficiency enhanced microglial phagocytosis. All the KD phenotypes were rescued by expression of an shRNA-resistant Syt11, while overexpression of Syt11 suppressed cytokine secretion and phagocytosis. Importantly, Syt11 also inhibited microglial phagocytosis of α-synuclein fibrils, supporting its association with Parkinson disease. Taken together, we propose that Syt11 suppresses microglial activation under both physiological and pathological conditions through the inhibition of cytokine secretion and phagocytosis.
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Affiliation(s)
- Cuilian Du
- Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,Department of Neurobiology, School of Basic Medical Science, Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Capital Medical University, Beijing, China
| | - Yalong Wang
- Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Feifan Zhang
- Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Shuxin Yan
- Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Yuan Guan
- Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Xiaoli Gong
- Department of Physiology, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Ting Zhang
- Department of Neurobiology, School of Basic Medical Science, Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Capital Medical University, Beijing, China
| | - Xiuyu Cui
- Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
| | - Xiaomin Wang
- Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China.,Department of Neurobiology, School of Basic Medical Science, Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Capital Medical University, Beijing, China
| | - Claire Xi Zhang
- Key Laboratory for the Neurodegenerative Disorders of the Chinese Ministry of Education, Center of Parkinson's Disease, Beijing Institute for Brain Disorders, Capital Medical University, Beijing, China
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Kabayama H, Tokushige N, Takeuchi M, Kabayama M, Fukuda M, Mikoshiba K. Parkin promotes proteasomal degradation of synaptotagmin IV by accelerating polyubiquitination. Mol Cell Neurosci 2017; 80:89-99. [PMID: 28254618 DOI: 10.1016/j.mcn.2017.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/02/2017] [Accepted: 02/15/2017] [Indexed: 12/25/2022] Open
Abstract
Parkin is an E3 ubiquitin ligase whose mutations cause autosomal recessive juvenile Parkinson's disease (PD). Unlike the human phenotype, parkin knockout (KO) mice show no apparent dopamine neuron degeneration, although they demonstrate reduced expression and activity of striatal mitochondrial proteins believed to be necessary for neuronal survival. Instead, parkin-KO mice show reduced striatal evoked dopamine release, abnormal synaptic plasticity, and non-motor symptoms, all of which appear to mimic the preclinical features of Parkinson's disease. Extensive studies have screened candidate synaptic proteins responsible for reduced evoked dopamine release, and synaptotagmin XI (Syt XI), an isoform of Syt family regulating membrane trafficking, has been identified as a substrate of parkin in humans. However, its expression level is unaltered in the striatum of parkin-KO mice. Thus, the target(s) of parkin and the molecular mechanisms underlying the impaired dopamine release in parkin-KO mice remain unknown. In this study, we focused on Syt IV because of its highly homology to Syt XI, and because they share an evolutionarily conserved lack of Ca2+-binding capacity; thus, Syt IV plays an inhibitory role in Ca2+-dependent neurotransmitter release in PC12 cells and neurons in various brain regions. We found that a proteasome inhibitor increased Syt IV protein, but not Syt XI protein, in neuron-like, differentiated PC12 cells, and that parkin interacted with and polyubiquitinated Syt IV, thereby accelerating its protein turnover. Parkin overexpression selectively degraded Syt IV protein, but not Syt I protein (indispensable for Ca2+-dependent exocytosis), thus enhancing depolarization-dependent exocytosis. Furthermore, in parkin-KO mice, the level of striatal Syt IV protein was increased. Our data indicate a crucial role for parkin in the proteasomal degradation of Syt IV, and provide a potential mechanism of parkin-regulated, evoked neurotransmitter release.
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Affiliation(s)
- Hiroyuki Kabayama
- Laboratory for Developmental Neurobiology, Brain Science Institute, Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| | - Naoko Tokushige
- Laboratory for Developmental Neurobiology, Brain Science Institute, Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Makoto Takeuchi
- Laboratory for Developmental Neurobiology, Brain Science Institute, Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Miyuki Kabayama
- Division of Functional Morphology, Department of Basic Veterinary Medicine, School of Veterinary Medicine, Nippon Veterinary and Life Science University, 1-7-1 Kyonantyo, Musashino, Tokyo 180-8602, Japan
| | - Mitsunori Fukuda
- Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, Brain Science Institute, Institute of Physical and Chemical Research (RIKEN), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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Tratnjek L, Glavan G, Višnjar T, Živin M. Upregulation and axonal transport of synaptotagmin-IV in the direct-pathway medium spiny neurons in hemi-parkinsonian rats induced by dopamine D1 receptor stimulation. Eur J Neurosci 2016; 43:885-98. [PMID: 26750488 DOI: 10.1111/ejn.13161] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 12/05/2015] [Accepted: 12/26/2015] [Indexed: 01/06/2023]
Abstract
Synaptotagmin-IV (Syt-IV) may function as a regulator of Ca(2+) -dependent synaptic transmission. In the hemi-parkinsonian rats with unilateral lesions of dopaminergic nigrostriatal neurons Syt-IV and substance-P (SP) mRNAs could be upregulated within the dopaminergically hypersensitive striatum of the lesioned brain hemisphere via the stimulation of striatal dopamine D1 (D1-R), but not D2 receptors. The hypersensitive D1-R-mediated transmission may be the culprit for the undesired expression of levodopa-induced dyskinesia, implying the involvement of Syt-IV and SP in the process. First, striatal cellular phenotypes expressing Syt-IV were determined. It was found to be expressed in all striatal neurons and a small population of astrocytes. Then it was examined, if the D1-R-mediated upregulation of Syt-IV mRNA may result in the upregulation of the translated protein. It was found that, after acute stimulation with a selective D1 agonist, (±)-6-chloro-7,8-dihydroxy-3-allyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrobromide (SKF-82958), Syt-IV was elevated within the SP-expressing striatal neurons of the lesioned side. This was followed by the upregulation of Syt-IV, but not of its mRNA, within the ipsilateral target nuclei of the direct-pathway medium spiny neurons, indicating axonal transport of de novo synthesized protein to their SP-positive synaptic terminals. However, despite the striatal upregulation of SP and Syt-IV following a similar time-course, their subcellular co-localization within the axonal terminals was not found. It was therefore suggested that Syt-IV may regulate the hypersensitive striatal synaptic transmission, although via a SP-independent mechanism.
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Affiliation(s)
- Larisa Tratnjek
- Brain Research Laboratory, Medical Faculty, Institute of Pathophysiology, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia
| | - Gordana Glavan
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Tanja Višnjar
- Institute of Cell Biology, Medical Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Marko Živin
- Brain Research Laboratory, Medical Faculty, Institute of Pathophysiology, University of Ljubljana, Zaloška 4, 1000, Ljubljana, Slovenia
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Li D, Hérault K, Zylbersztejn K, Lauterbach MA, Guillon M, Oheim M, Ropert N. Astrocyte VAMP3 vesicles undergo Ca2+ -independent cycling and modulate glutamate transporter trafficking. J Physiol 2015; 593:2807-32. [PMID: 25864578 DOI: 10.1113/jp270362] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/07/2015] [Indexed: 01/26/2023] Open
Abstract
KEY POINTS Mouse cortical astrocytes express VAMP3 but not VAMP2. VAMP3 vesicles undergo Ca(2+) -independent exo- and endocytotic cycling at the plasma membrane. VAMP3 vesicle traffic regulates the recycling of plasma membrane glutamate transporters. cAMP modulates VAMP3 vesicle cycling and glutamate uptake. ABSTRACT Previous studies suggest that small synaptic-like vesicles in astrocytes carry vesicle-associated vSNARE proteins, VAMP3 (cellubrevin) and VAMP2 (synaptobrevin 2), both contributing to the Ca(2+) -regulated exocytosis of gliotransmitters, thereby modulating brain information processing. Here, using cortical astrocytes taken from VAMP2 and VAMP3 knock-out mice, we find that astrocytes express only VAMP3. The morphology and function of VAMP3 vesicles were studied in cultured astrocytes at single vesicle level with stimulated emission depletion (STED) and total internal reflection fluorescence (TIRF) microscopies. We show that VAMP3 antibodies label small diameter (∼80 nm) vesicles and that VAMP3 vesicles undergo Ca(2+) -independent exo-endocytosis. We also show that this pathway modulates the surface expression of plasma membrane glutamate transporters and the glutamate uptake by astrocytes. Finally, using pharmacological and optogenetic tools, we provide evidence suggesting that the cytosolic cAMP level influences astrocytic VAMP3 vesicle trafficking and glutamate transport. Our results suggest a new role for VAMP3 vesicles in astrocytes.
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Affiliation(s)
- Dongdong Li
- CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.,INSERM U603, Paris, F-75006 France; CNRS UMR 8154, Paris, F-75006 France, Neurophysiology and New Microscopies Laboratory, 45 rue des Saints Pères, Paris, F-75006, France
| | - Karine Hérault
- CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France
| | - Kathleen Zylbersztejn
- INSERM ERL U950, Paris, F-75013, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, F-75013, France.,CNRS, UMR 7592, Institut Jacques Monod, Paris, F-75013, France
| | - Marcel A Lauterbach
- Neurophotonics Laboratory, CNRS UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France
| | - Marc Guillon
- Neurophotonics Laboratory, CNRS UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France
| | - Martin Oheim
- CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.,INSERM U603, Paris, F-75006 France; CNRS UMR 8154, Paris, F-75006 France, Neurophysiology and New Microscopies Laboratory, 45 rue des Saints Pères, Paris, F-75006, France
| | - Nicole Ropert
- CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.,INSERM U603, Paris, F-75006 France; CNRS UMR 8154, Paris, F-75006 France, Neurophysiology and New Microscopies Laboratory, 45 rue des Saints Pères, Paris, F-75006, France
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Andersson SA, Olsson AH, Esguerra JLS, Heimann E, Ladenvall C, Edlund A, Salehi A, Taneera J, Degerman E, Groop L, Ling C, Eliasson L. Reduced insulin secretion correlates with decreased expression of exocytotic genes in pancreatic islets from patients with type 2 diabetes. Mol Cell Endocrinol 2012; 364:36-45. [PMID: 22939844 DOI: 10.1016/j.mce.2012.08.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 08/07/2012] [Accepted: 08/13/2012] [Indexed: 02/06/2023]
Abstract
Reduced insulin release has been linked to defect exocytosis in β-cells. However, whether expression of genes suggested to be involved in the exocytotic process (exocytotic genes) is altered in pancreatic islets from patients with type 2 diabetes (T2D), and correlate to insulin secretion, needs to be further investigated. Analysing expression levels of 23 exocytotic genes using microarray revealed reduced expression of five genes in human T2D islets (χ(2)=13.25; p<0.001). Gene expression of STX1A, SYT4, SYT7, SYT11, SYT13, SNAP25 and STXBP1 correlated negatively to in vivo measurements of HbA1c levels and positively to glucose stimulated insulin secretion (GSIS) in vitro in human islets. STX1A, SYT4 and SYT11 protein levels correspondingly decreased in human T2D islets. Moreover, silencing of SYT4 and SYT13 reduced GSIS in INS1-832/13 cells. Our data support that reduced expression of exocytotic genes contributes to impaired insulin secretion, and suggest decreased expression of these genes as part of T2D pathogenesis.
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Affiliation(s)
- Sofia A Andersson
- Islet Cell Exocytosis, Lund University Diabetes Centre, Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
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