1
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Okada M, Fukuyama K, Motomura E. Impacts of exposure to and subsequent discontinuation of clozapine on tripartite synaptic transmission. Br J Pharmacol 2024. [PMID: 39091175 DOI: 10.1111/bph.16503] [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: 10/01/2023] [Revised: 06/14/2024] [Accepted: 06/17/2024] [Indexed: 08/04/2024] Open
Abstract
BACKGROUND AND PURPOSE Clozapine is an effective antipsychotic for treatment-resistant schizophrenia, but its discontinuation leads to discontinuation syndrome/catatonia complicated by benzodiazepine-resistance and rhabdomyolysis. EXPERIMENTAL APPROACH This study determined time-dependent effects of exposure and subsequent discontinuation of clozapine on expression of connexin43, 5-HT receptors, intracellular L-β-aminoisobutyrate (L-BAIBA) and 2nd-messengers and signalling of AMPK, PP2A and Akt in cultured astrocytes and rat frontal cortex. KEY RESULTS Intracellular L-BAIBA levels increased during clozapine exposure but immediately recovered after discontinuation. Both exposure to clozapine and L-BAIBA increased connexin43 and signalling of AMPK/Akt time-dependently, but reduced PP2A signalling, 5-HT receptor expression and IP3 level. These changes recovered within 2 weeks after discontinuation, while 5-HT receptors and IP3 transiently increased during the recovery process. L-BAIBA activated AMPK signalling, leading to attenuated PP2A signalling. Astroglial D-serine release was increased by clozapine exposure but continued to increase within 1 week after discontinuation via activation of IP3 receptor function. CONCLUSION AND IMPLICATIONS Clozapine discontinuation restored PP2A signalling due to decreased L-BAIBA, increased 5-HT receptor expression via probably enhanced 5-HT receptor recycling, but increased astroglial D-serine release persisted by transiently activated IP3 receptors via transiently increased IP3 level. Decreased L-BAIBA caused by clozapine discontinuation is, at least partially, involved in the transiently increased 5-HT receptor and astroglial D-serine release.
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Affiliation(s)
- Motohiro Okada
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Kouji Fukuyama
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Japan
| | - Eishi Motomura
- Department of Neuropsychiatry, Division of Neuroscience, Graduate School of Medicine, Mie University, Tsu, Japan
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2
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Bayonés L, Guerra-Fernández MJ, Hinostroza F, Báez-Matus X, Vásquez-Navarrete J, Gallo LI, Parra S, Martínez AD, González-Jamett A, Marengo FD, Cárdenas AM. Gain-of-Function Dynamin-2 Mutations Linked to Centronuclear Myopathy Impair Ca2+-Induced Exocytosis in Human Myoblasts. Int J Mol Sci 2022; 23:ijms231810363. [PMID: 36142275 PMCID: PMC9499313 DOI: 10.3390/ijms231810363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 08/26/2022] [Accepted: 09/02/2022] [Indexed: 11/16/2022] Open
Abstract
Gain-of-function mutations of dynamin-2, a mechano-GTPase that remodels membrane and actin filaments, cause centronuclear myopathy (CNM), a congenital disease that mainly affects skeletal muscle tissue. Among these mutations, the variants p.A618T and p.S619L lead to a gain of function and cause a severe neonatal phenotype. By using total internal reflection fluorescence microscopy (TIRFM) in immortalized human myoblasts expressing the pH-sensitive fluorescent protein (pHluorin) fused to the insulin-responsive aminopeptidase IRAP as a reporter of the GLUT4 vesicle trafficking, we measured single pHluorin signals to investigate how p.A618T and p.S619L mutations influence exocytosis. We show here that both dynamin-2 mutations significantly reduced the number and durations of pHluorin signals induced by 10 μM ionomycin, indicating that in addition to impairing exocytosis, they also affect the fusion pore dynamics. These mutations also disrupt the formation of actin filaments, a process that reportedly favors exocytosis. This altered exocytosis might importantly disturb the plasmalemma expression of functional proteins such as the glucose transporter GLUT4 in skeletal muscle cells, impacting the physiology of the skeletal muscle tissue and contributing to the CNM disease.
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Affiliation(s)
- Lucas Bayonés
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - María José Guerra-Fernández
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Fernando Hinostroza
- Centro de Investigación de Estudios Avanzados del Maule (CIEAM), Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca 3460000, Chile
- Centro de Investigación en Neuropsicología y Neurociencias Cognitivas (CINPSI Neurocog), Facultad de Ciencias de la Salud, Universidad Católica del Maule, Talca 3460000, Chile
| | - Ximena Báez-Matus
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Jacqueline Vásquez-Navarrete
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Luciana I. Gallo
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
| | - Sergio Parra
- Instituto de Fisiología Celular—Neurociencias, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico
| | - Agustín D. Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
| | - Arlek González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
- Escuela de Química y Farmacia, Facultad de Farmacia, Universidad de Valparaíso, Valparaíso 2360102, Chile
| | - Fernando D. Marengo
- Instituto de Fisiología, Biología Molecular y Neurociencias, CONICET, Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires 1428, Argentina
- Correspondence: (F.D.M.); (A.M.C.)
| | - Ana M. Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Gran Bretaña 1111, Valparaíso 2360102, Chile
- Correspondence: (F.D.M.); (A.M.C.)
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3
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Gao R, Li X, Gao H, Zhao K, Liu X, Liu J, Wang Q, Zhu Y, Chen H, Xiang S, Zhan Y, Yin R, Yu M, Ning H, Yang X, Li C. Protein phosphatase 2A catalytic subunit β suppresses PMA/ionomycin-induced T-cell activation by negatively regulating PI3K/Akt signaling. FEBS J 2022; 289:4518-4535. [PMID: 35068054 DOI: 10.1111/febs.16370] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 12/16/2021] [Accepted: 01/20/2022] [Indexed: 01/07/2023]
Abstract
The precise regulation of the T-cell activation process is critical for overall immune homeostasis. Although protein phosphatase 2A (PP2A) is required for T-cell development and function, the role of PPP2CB, which is the catalytic subunit β isoform of PP2A, remains unknown. In the present study, using a T cell-specific knockout mouse of PPP2CB (PPP2CBfl/fl Lck-Cre+ ), we demonstrated that PPP2CB was dispensable for T-cell development in the thymus and peripheral lymphoid organs. Furthermore, PPP2CB deletion did not affect T-cell receptor (TCR)-induced T-cell activation or cytokine-induced T-cell responses; however, it specifically enhanced phorbol myristate acetate (PMA) plus ionomycin-induced T-cell activation with increased cellular proliferation, elevated CD69 and CD25 expression, and enhanced cytokine production (inteferon-γ, interleukin-2 and tumor necrosis factor). Mechanistic analyses suggested that the PPP2CB deletion enhanced activation of the phosphoinositide 3-kinase/Akt signaling pathway and Ca2+ flux following stimulation with PMA plus ionomycin. Moreover, the specific PI3K inhibitor rescued the augmented cell activation in PPP2CB-deficient T cells. Using mass spectrometry-based phospho-peptide analysis, we identified potential substrates of PPP2CB during PMA plus ionomycin-induced T-cell activation. Collectively, our study provides evidence of the specific role of PPP2CB in controlling PMA plus ionomycin-induced T-cell activation.
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Affiliation(s)
- Rui Gao
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Xin Li
- Department of Hematopoietic Stem Cell Transplantation, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Huiying Gao
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Ke Zhao
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Xian Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Jinfang Liu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Qi Wang
- School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Yaxin Zhu
- School of Life Sciences, Hebei University, Baoding, China
| | - Hui Chen
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Shensi Xiang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Yiqun Zhan
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Ronghua Yin
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Miao Yu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Hongmei Ning
- Department of Hematopoietic Stem Cell Transplantation, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Xiaoming Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
| | - Changyan Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences (Beijing), Beijing Institute of Lifeomics, China
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4
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Neyrinck K, Van Den Daele J, Vervliet T, De Smedt J, Wierda K, Nijs M, Vanbokhoven T, D'hondt A, Planque M, Fendt SM, Shih PY, Seibt F, Almenar JP, Kreir M, Kumar D, Broccoli V, Bultynck G, Ebneth A, Cabrera-Socorro A, Verfaillie C. SOX9-induced Generation of Functional Astrocytes Supporting Neuronal Maturation in an All-human System. Stem Cell Rev Rep 2021; 17:1855-1873. [PMID: 33982246 PMCID: PMC8553725 DOI: 10.1007/s12015-021-10179-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2021] [Indexed: 11/29/2022]
Abstract
Astrocytes, the main supportive cell type of the brain, show functional impairments upon ageing and in a broad spectrum of neurological disorders. Limited access to human astroglia for pre-clinical studies has been a major bottleneck delaying our understanding of their role in brain health and disease. We demonstrate here that functionally mature human astrocytes can be generated by SOX9 overexpression for 6 days in pluripotent stem cell (PSC)-derived neural progenitor cells. Inducible (i)SOX9-astrocytes display functional properties comparable to primary human astrocytes comprising glutamate uptake, induced calcium responses and cytokine/growth factor secretion. Importantly, electrophysiological properties of iNGN2-neurons co-cultured with iSOX9-astrocytes are indistinguishable from gold-standard murine primary cultures. The high yield, fast timing and the possibility to cryopreserve iSOX9-astrocytes without losing functional properties makes them suitable for scaled-up production for high-throughput analyses. Our findings represent a step forward to an all-human iPSC-derived neural model for drug development in neuroscience and towards the reduction of animal use in biomedical research.
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Affiliation(s)
- Katrien Neyrinck
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium.
| | - Johanna Van Den Daele
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium.
| | - Tim Vervliet
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Jonathan De Smedt
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Keimpe Wierda
- Electrophysiology Expert Unit, VIB-KU Leuven Center for Brain & Disease Research, Leuven, 3000, Belgium
| | - Melissa Nijs
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Tom Vanbokhoven
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Astrid D'hondt
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium
| | - Mélanie Planque
- Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncoloy, KU Leuven and Leuven Cancer Institute (LKI), Leuven, 3000, Belgium
- Laboratory of Cellular Metabolism and Metabolic Regulation, VIB-KU Leuven Center for Cancer Biology, VIB, Leuven, 3000, Belgium
| | - Sarah-Maria Fendt
- Laboratory of Cellular Metabolism and Metabolic Regulation, Department of Oncoloy, KU Leuven and Leuven Cancer Institute (LKI), Leuven, 3000, Belgium
- Laboratory of Cellular Metabolism and Metabolic Regulation, VIB-KU Leuven Center for Cancer Biology, VIB, Leuven, 3000, Belgium
| | - Pei-Yu Shih
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Frederik Seibt
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Juan Pita Almenar
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Mohamed Kreir
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Devesh Kumar
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | - Vania Broccoli
- Division of Neuroscience, IRCCS, San Raffaele Scientific Hospital, 20132, Milan, Italy
- Institute of Neuroscience, National Research Council (CNR), 20129, Milan, Italy
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Andreas Ebneth
- Division of Janssen Pharmaceutica, Janssen Research & Development, Beerse, 2340, Belgium
| | | | - Catherine Verfaillie
- Stem Cell Institute, Department of Development and Regeneration, KU Leuven, Leuven, 3000, Belgium.
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5
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Transmembrane Prolyl 4-Hydroxylase is a Novel Regulator of Calcium Signaling in Astrocytes. eNeuro 2021; 8:ENEURO.0253-20.2020. [PMID: 33298456 PMCID: PMC7814479 DOI: 10.1523/eneuro.0253-20.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 11/09/2020] [Accepted: 11/27/2020] [Indexed: 12/11/2022] Open
Abstract
Prolyl 4-hydroxylases (P4Hs) have vital roles in regulating collagen synthesis and hypoxia response. A transmembrane P4H (P4H-TM) is a recently identified member of the family. Biallelic loss of function P4H-TM mutations cause a severe autosomal recessive intellectual disability syndrome in humans, but functions of P4H-TM are essentially unknown at cellular level. Our microarray data on P4h-tm -/- mouse cortexes where P4H-TM is abundantly expressed indicated expression changes in genes involved in calcium signaling and expression of several calcium sequestering ATPases was upregulated in P4h-tm -/- primary mouse astrocytes. Cytosolic and intraorganellar calcium imaging of P4h-tm -/- cells revealed that receptor-operated calcium entry (ROCE) and store-operated calcium entry (SOCE) and calcium re-uptake by mitochondria were compromised. HIF1, but not HIF2, was found to be a key mediator of the P4H-TM effect on calcium signaling. Furthermore, total internal reflection fluorescence (TIRF) imaging showed that calcium agonist-induced gliotransmission was attenuated in P4h-tm -/- astrocytes. This phenotype was accompanied by redistribution of mitochondria from distal processes to central parts of the cell body and decreased intracellular ATP content. Our data show that P4H-TM is a novel regulator of calcium dynamics and gliotransmission.
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6
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Ucuncu E, Rajamani K, Wilson MSC, Medina-Cano D, Altin N, David P, Barcia G, Lefort N, Banal C, Vasilache-Dangles MT, Pitelet G, Lorino E, Rabasse N, Bieth E, Zaki MS, Topcu M, Sonmez FM, Musaev D, Stanley V, Bole-Feysot C, Nitschké P, Munnich A, Bahi-Buisson N, Fossoud C, Giuliano F, Colleaux L, Burglen L, Gleeson JG, Boddaert N, Saiardi A, Cantagrel V. MINPP1 prevents intracellular accumulation of the chelator inositol hexakisphosphate and is mutated in Pontocerebellar Hypoplasia. Nat Commun 2020; 11:6087. [PMID: 33257696 PMCID: PMC7705663 DOI: 10.1038/s41467-020-19919-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 10/29/2020] [Indexed: 12/13/2022] Open
Abstract
Inositol polyphosphates are vital metabolic and secondary messengers, involved in diverse cellular functions. Therefore, tight regulation of inositol polyphosphate metabolism is essential for proper cell physiology. Here, we describe an early-onset neurodegenerative syndrome caused by loss-of-function mutations in the multiple inositol-polyphosphate phosphatase 1 gene (MINPP1). Patients are found to have a distinct type of Pontocerebellar Hypoplasia with typical basal ganglia involvement on neuroimaging. We find that patient-derived and genome edited MINPP1−/− induced stem cells exhibit an inefficient neuronal differentiation combined with an increased cell death. MINPP1 deficiency results in an intracellular imbalance of the inositol polyphosphate metabolism. This metabolic defect is characterized by an accumulation of highly phosphorylated inositols, mostly inositol hexakisphosphate (IP6), detected in HEK293 cells, fibroblasts, iPSCs and differentiating neurons lacking MINPP1. In mutant cells, higher IP6 level is expected to be associated with an increased chelation of intracellular cations, such as iron or calcium, resulting in decreased levels of available ions. These data suggest the involvement of IP6-mediated chelation on Pontocerebellar Hypoplasia disease pathology and thereby highlight the critical role of MINPP1 in the regulation of human brain development and homeostasis. Tight regulation of inositol polyphosphate metabolism is essential for proper cell physiology. Here, the authors describe an early-onset neurodegenerative syndrome caused by loss-of-function mutations in the MINPP1 gene, characterised by intracellular imbalance of inositol polyphosphate metabolism.
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Affiliation(s)
- Ekin Ucuncu
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Karthyayani Rajamani
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Miranda S C Wilson
- MRC Laboratory for Molecular Cell Biology, University College London, WC1E 6BT, London, UK
| | - Daniel Medina-Cano
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Nami Altin
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Pierre David
- Transgenesis Platform, Laboratoire d'Expérimentation Animale et Transgenèse (LEAT), Imagine Institute, Structure Fédérative de Recherche Necker INSERM US24/CNRS UMS3633, 75015, Paris, France
| | - Giulia Barcia
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France.,Département de Génétique Médicale, AP-HP, Hôpital Necker-Enfants Malades, F-75015, Paris, France
| | - Nathalie Lefort
- Université de Paris, iPSC Core Facility, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Céline Banal
- Université de Paris, iPSC Core Facility, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | | | - Gaële Pitelet
- Service de Neuropédiatrie, CHU Nice, 06200, Nice, France
| | - Elsa Lorino
- ESEAN, 44200 Nantes, Service de maladies chroniques de l'enfant, CHU Nantes, 44093, Nantes, France
| | - Nathalie Rabasse
- Service de pédiatrie, hôpital d'Antibes-Juan-les-Pins, 06600, Antibes-Juan-les-Pins, France
| | - Eric Bieth
- Service de Génétique Médicale, CHU Toulouse, 31059, Toulouse, France
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division, National Research Centre, Cairo, 12311, Egypt
| | - Meral Topcu
- Department of Child Neurology, Faculty of Medicine, Hacettepe University, Ankara, 06100, Turkey
| | - Fatma Mujgan Sonmez
- Guven Hospital, Child Neurology Department, Ankara, Turkey.,Department of Child Neurology, Faculty of Medicine, Karadeniz Technical University, Trabzon, 61080, Turkey
| | - Damir Musaev
- Laboratory for Pediatric Brain Diseases, Rady Children's Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Valentina Stanley
- Laboratory for Pediatric Brain Diseases, Rady Children's Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Christine Bole-Feysot
- Université de Paris, Genomics Platform, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Patrick Nitschké
- Université de Paris, Bioinformatics Core Facility, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Arnold Munnich
- Université de Paris, Translational Genetics Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Nadia Bahi-Buisson
- Université de Paris, Genetics and Development of the Cerebral Cortex Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Catherine Fossoud
- Centre de Référence des Troubles des Apprentissages, Hôpitaux Pédiatriques de Nice CHU-Lenval, 06200, Nice, France
| | - Fabienne Giuliano
- Service de Génétique Médicale, Centre Hospitalier Universitaire de Nice, 06202, Nice, France
| | - Laurence Colleaux
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France
| | - Lydie Burglen
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France.,Centre de Référence des Malformations et Maladies Congénitales du Cervelet, Département de Génétique, AP-HP, Sorbonne Université, Hôpital Trousseau, 75012, Paris, France
| | - Joseph G Gleeson
- Laboratory for Pediatric Brain Diseases, Rady Children's Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, 92093, USA
| | - Nathalie Boddaert
- Département de radiologie pédiatrique, INSERM UMR 1163 and INSERM U1000, AP-HP, Hôpital Necker-Enfants Malades, F-75015, Paris, France
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, WC1E 6BT, London, UK.
| | - Vincent Cantagrel
- Université de Paris, Developmental Brain Disorders Laboratory, Imagine Institute, INSERM UMR 1163, F-75015, Paris, France.
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7
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BRAF and NRAS mutated melanoma: Different Ca 2+ responses, Na +/Ca 2+ exchanger expression, and sensitivity to inhibitors. Cell Calcium 2020; 90:102241. [PMID: 32562975 DOI: 10.1016/j.ceca.2020.102241] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/27/2020] [Accepted: 06/04/2020] [Indexed: 01/10/2023]
Abstract
Calcium is a ubiquitous intracellular second messenger, playing central roles in the regulation of several biological processes. Alterations in Ca2+ homeostasis and signaling are an important feature of tumor cells to acquire proliferative and survival advantages, which include structural and functional changes in storage capacity, channels, and pumps. Here, we investigated the differences in Ca2+ homeostasis in vemurafenib-responsive and non-responsive melanoma cells. Also, the expression of the Na+/Ca2+ exchanger (NCX) and the impact of its inhibition were studied. For this, it was used B-RAFV600E and NRASQ61R-mutated human melanoma cells. The intracellular Ca2+ chelator BAPTA-AM decreased the viability of SK-MEL-147 but not of SK-MEL-19 and EGTA sensitized NRASQ61R-mutated cells to vemurafenib. These cells also presented a smaller response to thapsargin and ionomycin regarding the cytosolic Ca2+ levels in relation to SK-MEL-19, which was associated to an increased expression of NCX1, NO basal levels, and sensitivity to NCX inhibitors. These data highlight the differences between B-RAFV600E and NRASQ61R-mutated melanoma cells in response to Ca2+ stimuli and point to the potential combination of clinically used chemotherapeutic drugs, including vemurafenib, with NCX inhibitors as a new therapeutic strategy to the treatment of melanoma.
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8
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Romero-Masters JC, Huebner SM, Ohashi M, Bristol JA, Benner BE, Barlow EA, Turk GL, Nelson SE, Baiu DC, Van Sciver N, Ranheim EA, Gumperz J, Sherer NM, Farrell PJ, Johannsen EC, Kenney SC. B cells infected with Type 2 Epstein-Barr virus (EBV) have increased NFATc1/NFATc2 activity and enhanced lytic gene expression in comparison to Type 1 EBV infection. PLoS Pathog 2020; 16:e1008365. [PMID: 32059024 PMCID: PMC7046292 DOI: 10.1371/journal.ppat.1008365] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 02/27/2020] [Accepted: 01/29/2020] [Indexed: 12/30/2022] Open
Abstract
Humans are infected with two distinct strains (Type 1 (T1) and Type 2 (T2)) of Epstein-Barr virus (EBV) that differ substantially in their EBNA2 and EBNA 3A/B/C latency genes and the ability to transform B cells in vitro. While most T1 EBV strains contain the "prototype" form of the BZLF1 immediate-early promoter ("Zp-P"), all T2 strains contain the "Zp-V3" variant, which contains an NFAT binding motif and is activated much more strongly by B-cell receptor signalling. Whether B cells infected with T2 EBV are more lytic than cells infected with T1 EBV is unknown. Here we show that B cells infected with T2 EBV strains (AG876 and BL5) have much more lytic protein expression compared to B cells infected with T1 EBV strains (M81, Akata, and Mutu) in both a cord blood-humanized (CBH) mouse model and EBV-transformed lymphoblastoid cell lines (LCLs). Although T2 LCLs grow more slowly than T1 LCLs, both EBV types induce B-cell lymphomas in CBH mice. T1 EBV strains (M81 and Akata) containing Zp-V3 are less lytic than T2 EBV strains, suggesting that Zp-V3 is not sufficient to confer a lytic phenotype. Instead, we find that T2 LCLs express much higher levels of activated NFATc1 and NFATc2, and that cyclosporine (an NFAT inhibitor) and knockdown of NFATc2 attenuate constitutive lytic infection in T2 LCLs. Both NFATc1 and NFATc2 induce lytic EBV gene expression when combined with activated CAMKIV (which is activated by calcium signaling and activates MEF2D) in Burkitt Akata cells. Together, these results suggest that B cells infected with T2 EBV are more lytic due to increased activity of the cellular NFATc1/c2 transcription factors in addition to the universal presence of the Zp-V3 form of BZLF1 promoter.
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Affiliation(s)
- James C. Romero-Masters
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Shane M. Huebner
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Makoto Ohashi
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jillian A. Bristol
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Bayleigh E. Benner
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Elizabeth A. Barlow
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Gail L. Turk
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Scott E. Nelson
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Dana C. Baiu
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Nicholas Van Sciver
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Erik A. Ranheim
- Department of Pathology and Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jenny Gumperz
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Nathan M. Sherer
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Paul J. Farrell
- Section of Virology, Imperial College Faculty of Medicine, Norfolk Place, London, United Kingdom
| | - Eric C. Johannsen
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Shannon C. Kenney
- Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail:
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9
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Rogers RC, Burke SJ, Collier JJ, Ritter S, Hermann GE. Evidence that hindbrain astrocytes in the rat detect low glucose with a glucose transporter 2-phospholipase C-calcium release mechanism. Am J Physiol Regul Integr Comp Physiol 2020; 318:R38-R48. [PMID: 31596114 PMCID: PMC6985801 DOI: 10.1152/ajpregu.00133.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Astrocytes generate robust cytoplasmic calcium signals in response to reductions in extracellular glucose. This calcium signal, in turn, drives purinergic gliotransmission, which controls the activity of catecholaminergic (CA) neurons in the hindbrain. These CA neurons are critical to triggering glucose counter-regulatory responses (CRRs) that, ultimately, restore glucose homeostasis via endocrine and behavioral means. Although the astrocyte low-glucose sensor involvement in CRR has been accepted, it is not clear how astrocytes produce an increase in intracellular calcium in response to a decrease in glucose. Our ex vivo calcium imaging studies of hindbrain astrocytes show that the glucose type 2 transporter (GLUT2) is an essential feature of the astrocyte glucosensor mechanism. Coimmunoprecipitation assays reveal that the recombinant GLUT2 binds directly with the recombinant Gq protein subunit that activates phospholipase C (PLC). Additional calcium imaging studies suggest that GLUT2 may be connected to a PLC-endoplasmic reticular-calcium release mechanism, which is amplified by calcium-induced calcium release (CICR). Collectively, these data help outline a potential mechanism used by astrocytes to convert information regarding low-glucose levels into intracellular changes that ultimately regulate the CRR.
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Affiliation(s)
- Richard C. Rogers
- 1Laboratory of Autonomic Neuroscience, Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - Susan J. Burke
- 2Laboratory of Immunogenetics, Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - J. Jason Collier
- 3Laboratory of Islet Biology and Inflammation, Pennington Biomedical Research Center, Baton Rouge, Louisiana
| | - Sue Ritter
- 4Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman, Washington
| | - Gerlinda E. Hermann
- 1Laboratory of Autonomic Neuroscience, Pennington Biomedical Research Center, Baton Rouge, Louisiana
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10
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Reuschlein AK, Jakobsen E, Mertz C, Bak LK. Aspects of astrocytic cAMP signaling with an emphasis on the putative power of compartmentalized signals in health and disease. Glia 2019; 67:1625-1636. [PMID: 31033018 DOI: 10.1002/glia.23622] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/29/2019] [Accepted: 03/29/2019] [Indexed: 12/17/2022]
Abstract
This review discusses aspects of known and putative compartmentalized 3',5'-cyclic adenosine monophosphate (cAMP) signaling in astrocytes, a cell type that has turned out to be a key player in brain physiology and pathology. cAMP has attracted less attention than Ca2+ in recent years, but could turn out to rival Ca2+ in its potential to drive cellular functions and responses to intra- and extracellular cues. Further, Ca2+ and cAMP are known to engage in extensive crosstalk and cAMP signals often take place within subcellular compartments revolving around multi-protein signaling complexes; however, we know surprisingly little about this in astrocytes. Here, we review aspects of astrocytic cAMP signaling, provide arguments for an increased interest in this subject, suggest possible future research directions within the field, and discuss putative drug targets.
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Affiliation(s)
- Ann-Kathrin Reuschlein
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emil Jakobsen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Christoffer Mertz
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lasse K Bak
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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11
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Layhadi JA, Fountain SJ. Influence of ER leak on resting cytoplasmic Ca 2+ and receptor-mediated Ca 2+ signalling in human macrophage. Biochem Biophys Res Commun 2017; 487:633-639. [PMID: 28435065 DOI: 10.1016/j.bbrc.2017.04.106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 04/19/2017] [Indexed: 01/26/2023]
Abstract
Mechanisms controlling endoplasmic reticulum (ER) Ca2+ homeostasis are important regulators of resting cytoplasmic Ca2+ concentration ([Ca2+]cyto) and receptor-mediated Ca2+ signalling. Here we investigate channels responsible for ER Ca2+ leak in THP-1 macrophage and human primary macrophage. In the absence of extracellular Ca2+ we employ ionomycin action at the plasma membrane to stimulate ER Ca2+ leak. Under these conditions ionomycin elevates [Ca2+]cyto revealing a Ca2+ leak response which is abolished by thapsigargin. IP3 receptors (Xestospongin C, 2-APB), ryanodine receptors (dantrolene), and translocon (anisomycin) inhibition facilitated ER Ca2+ leak in model macrophage, with translocon inhibition also reducing resting [Ca2+]cyto. In primary macrophage, translocon inhibition blocks Ca2+ leak but does not influence resting [Ca2+]cyto. We identify a role for translocon-mediated ER Ca2+ leak in receptor-mediated Ca2+ signalling in both model and primary human macrophage, whereby the Ca2+ response to ADP (P2Y receptor agonist) is augmented following anisomycin treatment. In conclusion, we demonstrate a role of ER Ca2+ leak via the translocon in controlling resting cytoplasmic Ca2+ in model macrophage and receptor-mediated Ca2+ signalling in model macrophage and primary macrophage.
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Affiliation(s)
- Janice A Layhadi
- School of Biological Sciences, Biomedical Research Centre, University of East Anglia, Norwich Research Park, NR4 7TJ, UK
| | - Samuel J Fountain
- School of Biological Sciences, Biomedical Research Centre, University of East Anglia, Norwich Research Park, NR4 7TJ, UK.
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12
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Leis HJ, Windischhofer W. Ionomycin induces prostaglandin E2 formation in murine osteoblastic MC3T3-E1 cells via mechanisms independent of its ionophoric nature. Biochem Cell Biol 2016; 94:236-40. [PMID: 27065246 DOI: 10.1139/bcb-2015-0148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ionomycin and A23187 are divalent cation ionophores with a marked preference for calcium. Studies using these ionophores have almost exclusively interpreted their results in the light of calcium elevation. It was the aim of this study to investigate the effects of ionomycin in osteoblatic MC3T3-E1 cells that are not attributable to its ionophoric properties. Thus, we have found that in contrast to A23187, ionomycin shows similar effects on prostaglandin E2 formation as bradykinin and endothelin-1, being potentiated by extracellular nickel and inhibited by cholera toxin and pertussis toxin. Our data strongly suggest that inomycin, at least in part, exerts its effects via specific binding to a G-protein coupled receptor, thereby evoking downstream cellular events like arachidonate release with subsequent prostaglandin formation.
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Affiliation(s)
- Hans Jörg Leis
- University Hospital of Youth and Adolescence Medicine, Medical University of Graz, Research Unit of Analytical Mass Spectrometry, Cell Biology and Biochemistry of Inborn Errors of Metabolism, Auenbruggerplatz 34/2, A-8036 Graz, Austria.,University Hospital of Youth and Adolescence Medicine, Medical University of Graz, Research Unit of Analytical Mass Spectrometry, Cell Biology and Biochemistry of Inborn Errors of Metabolism, Auenbruggerplatz 34/2, A-8036 Graz, Austria
| | - Werner Windischhofer
- University Hospital of Youth and Adolescence Medicine, Medical University of Graz, Research Unit of Analytical Mass Spectrometry, Cell Biology and Biochemistry of Inborn Errors of Metabolism, Auenbruggerplatz 34/2, A-8036 Graz, Austria.,University Hospital of Youth and Adolescence Medicine, Medical University of Graz, Research Unit of Analytical Mass Spectrometry, Cell Biology and Biochemistry of Inborn Errors of Metabolism, Auenbruggerplatz 34/2, A-8036 Graz, Austria
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13
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Xiong X, Wang G, Tao R, Wu P, Kono T, Li K, Ding WX, Tong X, Tersey SA, Harris RA, Mirmira RG, Evans-Molina C, Dong XC. Sirtuin 6 regulates glucose-stimulated insulin secretion in mouse pancreatic beta cells. Diabetologia 2016; 59:151-160. [PMID: 26471901 PMCID: PMC4792692 DOI: 10.1007/s00125-015-3778-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/22/2015] [Indexed: 12/31/2022]
Abstract
AIMS/HYPOTHESIS Sirtuin 6 (SIRT6) has been implicated in ageing, DNA repair and metabolism; however, its function in pancreatic beta cells is unclear. The aim of this study is to elucidate the role of SIRT6 in pancreatic beta cells. METHODS To investigate the function of SIRT6 in pancreatic beta cells, we performed Sirt6 gene knockdown in MIN6 cells and generated pancreatic- and beta cell-specific Sirt6 knockout mice. Islet morphology and glucose-stimulated insulin secretion (GSIS) were analysed. Glycolysis and oxygen consumption rates in SIRT6-deficient beta cells were measured. Cytosolic calcium was monitored using the Fura-2-AM fluorescent probe (Invitrogen, Grand Island, NY, USA). Mitochondria were analysed by immunoblots and electron microscopy. RESULTS Sirt6 knockdown in MIN6 beta cells led to a significant decrease in GSIS. Pancreatic beta cell Sirt6 knockout mice showed a ~50% decrease in GSIS. The knockout mouse islets had lower ATP levels compared with the wild-type controls. Mitochondrial oxygen consumption rates were significantly decreased in the SIRT6-deficient beta cells. Cytosolic calcium dynamics in response to glucose or potassium chloride were attenuated in the Sirt6 knockout islets. Numbers of damaged mitochondria were increased and mitochondrial complex levels were decreased in the SIRT6-deficient islets. CONCLUSIONS/INTERPRETATION These data suggest that SIRT6 is important for GSIS from pancreatic beta cells and activation of SIRT6 may be useful to improve insulin secretion in diabetes.
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Affiliation(s)
- Xiwen Xiong
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
| | - Gaihong Wang
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
| | - Rongya Tao
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
| | - Pengfei Wu
- Richard Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA
| | - Tatsuyoshi Kono
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kevin Li
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Wen-Xing Ding
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Xin Tong
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sarah A Tersey
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Robert A Harris
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA
- Richard Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA
| | - Raghavendra G Mirmira
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Carmella Evans-Molina
- Richard Roudebush Veterans Affairs Medical Center, Indianapolis, IN, USA
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - X Charlie Dong
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN, 46202, USA.
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14
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Kaja S, Payne AJ, Patel KR, Naumchuk Y, Koulen P. Differential subcellular Ca2+ signaling in a highly specialized subpopulation of astrocytes. Exp Neurol 2014; 265:59-68. [PMID: 25542978 DOI: 10.1016/j.expneurol.2014.12.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Revised: 11/26/2014] [Accepted: 12/12/2014] [Indexed: 11/24/2022]
Abstract
Recent evidence suggests that astrocytes do not serve a mere buffering function, but exhibit complex signaling pathways, disturbance of which contributes significantly to the pathophysiology of CNS diseases. Little is known regarding the intracellular signaling pathways in the specialized optic nerve head astrocytes (ONHAs), the major glia cell type in non-myelinated optic nerve head. Here we show the differential subcellular expression of intracellular Ca(2+) channels in ONHAs. Expression of type 1 and type 3 inositol-1-4-5,-trisphosphate receptors (IP3Rs) in the endoplasmic reticulum and type 2 IP3Rs in the nuclear envelope causes differential Ca(2+) release from intracellular stores in nuclear vs. cytosolic compartments. Our study identifies differential distribution and activity of Ca(2+) channels as molecular substrate and mechanism by which astrocytes independently regulate Ca(2+) transients in both cytoplasm and nucleoplasm, thereby controlling genomic and non-genomic cellular signaling, respectively. This provides excellent targets for therapeutics restoring pathological disturbances of intracellular Ca(2+) signaling present in glaucoma and other neurodegenerative disorders with astrocyte involvement.
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Affiliation(s)
- Simon Kaja
- Vision Research Center, Department of Ophthalmology, University of Missouri - Kansas City, School of Medicine, 2411 Holmes St., Kansas City, MO 64108, USA
| | - Andrew J Payne
- Vision Research Center, Department of Ophthalmology, University of Missouri - Kansas City, School of Medicine, 2411 Holmes St., Kansas City, MO 64108, USA
| | - Krupa R Patel
- Vision Research Center, Department of Ophthalmology, University of Missouri - Kansas City, School of Medicine, 2411 Holmes St., Kansas City, MO 64108, USA
| | - Yuliya Naumchuk
- Vision Research Center, Department of Ophthalmology, University of Missouri - Kansas City, School of Medicine, 2411 Holmes St., Kansas City, MO 64108, USA
| | - Peter Koulen
- Vision Research Center, Department of Ophthalmology, University of Missouri - Kansas City, School of Medicine, 2411 Holmes St., Kansas City, MO 64108, USA.
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15
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Toyoda H, Saito M, Sato H, Tanaka T, Ogawa T, Yatani H, Kawano T, Kanematsu T, Hirata M, Kang Y. Enhanced desensitization followed by unusual resensitization in GABAA receptors in phospholipase C-related catalytically inactive protein-1/2 double-knockout mice. Pflugers Arch 2014; 467:267-84. [PMID: 24737248 DOI: 10.1007/s00424-014-1511-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 03/24/2014] [Accepted: 03/27/2014] [Indexed: 11/29/2022]
Abstract
Phospholipase C-related catalytically inactive proteins (PRIP-1/2) are previously reported to be involved in the membrane trafficking of GABAA receptor (GABAAR) and the regulation of intracellular Ca(2+) stores. GABAAR-mediated currents can be regulated by the intracellular Ca(2+). However, in PRIP-1/2 double-knockout (PRIP-DKO) mice, it remains unclear whether the kinetic properties of GABAARs are modulated by the altered regulation of intracellular Ca(2+) stores. Here, we investigated whether GABAAR currents (IGABA) evoked by GABA puff in layer 3 (L3) pyramidal cells (PCs) of the barrel cortex are altered in PRIP-DKO mice. The deletion of PRIP-1/2 enhanced the desensitization of IGABA but induced a hump-like tail current (tail-I) at the GABA puff offset. IGABA and the hump-like tail-I were suppressed by GABAAR antagonists. The enhanced desensitization of IGABA and the hump-like tail-I in PRIP-DKO PCs were mediated by increases in the intracellular Ca(2+) concentration and were largely abolished by a calcineurin inhibitor and ruthenium red. Calcium imaging revealed that Ca(2+)-induced Ca(2+) release (CICR) and subsequent store-operated Ca(2+) entry (SOCE) are more potent in PRIP-DKO PCs than in wild-type PCs. A mathematical model revealed that a slowdown of GABA-unbinding rate and an acceleration of fast desensitization rate by enhancing its GABA concentration dependency are involved in the generation of hump-like tail-Is. These results suggest that in L3 PCs of the barrel cortex in PRIP-DKO mice, the increased calcineurin activity due to the potentiated CICR and SOCE enhances the desensitization of GABAARs and slows the GABA-unbinding rate, resulting in their unusual resensitization following removal of GABA.
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Affiliation(s)
- Hiroki Toyoda
- Department of Neuroscience and Oral Physiology, Osaka University Graduate School of Dentistry, 1-8, Yamadaoka, Suita, Osaka, 565-0871, Japan
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16
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Verkhratsky A, Reyes RC, Parpura V. TRP channels coordinate ion signalling in astroglia. Rev Physiol Biochem Pharmacol 2013; 166:1-22. [PMID: 23784619 DOI: 10.1007/112_2013_15] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Astroglial excitability is based on highly spatio-temporally coordinated fluctuations of intracellular ion concentrations, among which changes in Ca(2+) and Na(+) take the leading role. Intracellular signals mediated by Ca(2+) and Na(+) target numerous molecular cascades that control gene expression, energy production and numerous homeostatic functions of astrocytes. Initiation of Ca(2+) and Na(+) signals relies upon plasmalemmal and intracellular channels that allow fluxes of respective ions down their concentration gradients. Astrocytes express several types of TRP channels of which TRPA1 channels are linked to regulation of functional expression of GABA transporters, whereas TRPV4 channels are activated following osmotic challenges and are up-regulated in ischaemic conditions. Astrocytes also ubiquitously express several isoforms of TRPC channels of which heteromers assembled from TRPC1, 4 and/or 5 subunits that likely act as stretch-activated channels and are linked to store-operated Ca(2+) entry. The TRPC channels mediate large Na(+) fluxes that are associated with the endoplasmic reticulum Ca(2+) signalling machinery and hence coordinate Na(+) and Ca(2+) signalling in astroglia.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK,
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