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Zhang C, Tong F, Zhou B, He M, Liu S, Zhou X, Ma Q, Feng T, Du WJ, Yang H, Xu H, Xiao L, Xu ZZ, Zhu C, Wu R, Wang YQ, Han Q. TMC6 functions as a GPCR-like receptor to sense noxious heat via Gαq signaling. Cell Discov 2024; 10:66. [PMID: 38886367 PMCID: PMC11183229 DOI: 10.1038/s41421-024-00678-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 04/08/2024] [Indexed: 06/20/2024] Open
Abstract
Thermosensation is vital for the survival, propagation, and adaption of all organisms, but its mechanism is not fully understood yet. Here, we find that TMC6, a membrane protein of unknown function, is highly expressed in dorsal root ganglion (DRG) neurons and functions as a Gαq-coupled G protein-coupled receptor (GPCR)-like receptor to sense noxious heat. TMC6-deficient mice display a substantial impairment in noxious heat sensation while maintaining normal perception of cold, warmth, touch, and mechanical pain. Further studies show that TMC6 interacts with Gαq via its intracellular C-terminal region spanning Ser780 to Pro810. Specifically disrupting such interaction using polypeptide in DRG neurons, genetically ablating Gαq, or pharmacologically blocking Gαq-coupled GPCR signaling can replicate the phenotype of TMC6 deficient mice regarding noxious heat sensation. Noxious heat stimulation triggers intracellular calcium release from the endoplasmic reticulum (ER) of TMC6- but not control vector-transfected HEK293T cell, which can be significantly inhibited by blocking PLC or IP3R. Consistently, noxious heat-induced intracellular Ca2+ release from ER and action potentials of DRG neurons largely reduced when ablating TMC6 or blocking Gαq/PLC/IP3R signaling pathway as well. In summary, our findings indicate that TMC6 can directly function as a Gαq-coupled GPCR-like receptor sensing noxious heat.
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Affiliation(s)
- Chen Zhang
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Fang Tong
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Bin Zhou
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Mingdong He
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Shuai Liu
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Xiaomeng Zhou
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Qiang Ma
- School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Tianyu Feng
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Wan-Jie Du
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Huan Yang
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Hao Xu
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Lei Xiao
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China
| | - Zhen-Zhong Xu
- School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Cheng Zhu
- Tianjin Key Laboratory of Function and Application of Biological Macromolecular Structures, School of Life Sciences, Tianjin University, Tianjin, China
| | - Ruiqi Wu
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China.
| | - Yan-Qing Wang
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China.
| | - Qingjian Han
- Shanghai Stomatological Hospital & School of Stomatology, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Integrative Medicine and Neurobiology, School of Basic Medical Science, Fudan University, Shanghai, China.
- Shanghai Key Laboratory of Craniomaxillofacial Development and Diseases, Fudan University, Shanghai, China.
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2
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Salazar V, Bolaños P, del Castillo JR. Enteric Nervous System: Identification of a Novel Neuronal Sensory Network in the Duodenal Epithelium. J Histochem Cytochem 2023; 71:601-630. [PMID: 37791513 PMCID: PMC10617440 DOI: 10.1369/00221554231203038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 08/30/2023] [Indexed: 10/05/2023] Open
Abstract
The communication between the intestinal epithelium and the enteric nervous system has been considered indirect. Mechanical or chemical stimuli activate enteroendocrine cells inducing hormone secretion, which act on sub-epithelial nerve ends, activating the enteric nervous system. However, we identified an epithelial cell that expresses NKAIN4, a neuronal protein associated with the β-subunit of Na+/K+-ATPase. This cell overexpresses Na+/K+-ATPase and ouabain-insensitive Na+-ATPase, enzymes involved in active sodium transport. NKAIN4-positive cells also express neuronal markers as NeuN, acetylcholine-esterase, acetylcholine-transferase, α3- and α7-subunits of ACh receptors, glutamic-decarboxylase, and serotonin-receptor-7, suggesting they are neurons. NKAIN4-positive cells show a polarized shape with an oval body, an apical process finished in a knob-like terminal in contact with the lumen, a basal cilia body at the base of the apical extension, and basal axon-like soma projections connecting sub-epithelial nerve terminals, lymphoid nodules, glial cells, and enterochromaffin cells, forming a network that reaches the epithelial surface. We also showed, using retrograde labeling and immunofluorescence, that these cells receive afferent signals from the enteric nervous system. Finally, we demonstrated that acetylcholine activates NKAIN4-positive cells inducing Ca2+ mobilization and probably serotonin secretion in enterochromaffin cells. NKAIN4-positive cells are neurons that would form a part of a duodenal sensory network for physiological or noxious luminal stimuli.
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Affiliation(s)
- Víctor Salazar
- Light Microscopy Service, Biophysics and Biochemistry Center, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
| | - Pura Bolaños
- Laboratory of Cell Physiology, Biophysics and Biochemistry Center, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
| | - Jesús R. del Castillo
- Laboratory of Molecular Physiology, Biophysics and Biochemistry Center, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
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3
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Qian T, Wang H, Xia X, Li Y. Current and emerging methods for probing neuropeptide transmission. Curr Opin Neurobiol 2023; 81:102751. [PMID: 37487399 DOI: 10.1016/j.conb.2023.102751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 07/26/2023]
Abstract
Neuropeptides comprise the most diverse category of neurochemicals in the brain, playing critical roles in a wide range of physiological and pathophysiological processes. Monitoring neuropeptides with high spatial and temporal resolution is essential for understanding how peptidergic transmission is regulated throughout the central nervous system. In this review, we provide an overview of current non-optical and optical approaches used to detect neuropeptides, including their design principles, intrinsic properties, and potential limitations. We also highlight the advantages of using G protein‒coupled receptor (GPCR) activation‒based (GRAB) sensors to monitor neuropeptides in vivo with high sensitivity, good specificity, and high spatiotemporal resolution. Finally, we present a promising outlook regarding the development and optimization of new GRAB neuropeptide sensors, as well as their potential applications.
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Affiliation(s)
- Tongrui Qian
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing, 100871, China
| | - Huan Wang
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing, 100871, China
| | - Xiju Xia
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing, 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing, 100871, China; PKU-IDG/McGovern Institute for Brain Research, Beijing, 100871, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 100871, China; Chinese Institute for Brain Research, Beijing, 102206, China; National Biomedical Imaging Center, Peking University, Beijing, 100871, China.
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4
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Gouriou Y, Gonnot F, Wehbi M, Brun C, Gomez L, Bidaux G. High-sensitivity calcium biosensor on the mitochondrial surface reveals that IP3R channels participate in the reticular Ca2+ leak towards mitochondria. PLoS One 2023; 18:e0285670. [PMID: 37294746 PMCID: PMC10256219 DOI: 10.1371/journal.pone.0285670] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 04/27/2023] [Indexed: 06/11/2023] Open
Abstract
Genetically encoded biosensors based on fluorescent proteins (FPs) are widely used to monitor dynamics and sub-cellular spatial distribution of calcium ion (Ca2+) fluxes and their role in intracellular signaling pathways. The development of different mutations in the Ca2+-sensitive elements of the cameleon probes has allowed sensitive range of Ca2+ measurements in almost all cellular compartments. Region of the endoplasmic reticulum (ER) tethered to mitochondria, named as the mitochondrial-associated membranes (MAMs), has received an extended attention since the last 5 years. Indeed, as MAMs are essential for calcium homeostasis and mitochondrial function, molecular tools have been developed to assess quantitatively Ca2+ levels in the MAMs. However, sensitivity of the first generation Ca2+ biosensors on the surface of the outer-mitochondrial membrane (OMM) do not allow to measure μM or sub-μM changes in Ca2+ concentration which prevents to measure the native activity (unstimulated exogenously) of endogenous channels. In this study, we assembled a new ratiometric highly sensitive Ca2+ biosensor expressed on the surface of the outer-mitochondrial membrane (OMM). It allows the detection of smaller differences than the previous biosensor in or at proximity of the MAMs. Noteworthy, we demonstrated that IP3-receptors have an endogenous activity which participate to the Ca2+ leak channel on the surface of the OMM during hypoxia or when SERCA activity is blocked.
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Affiliation(s)
- Yves Gouriou
- Univ-Lyon CarMeN Laboratory, Inserm U1060, Université Claude Bernard Lyon 1, INRAE, Bron, France
- Hospices Civils de Lyon, Groupement Hospitalier EST, Département de Cardiologie, IHU-OPERA Bâtiment B13, Bron, France
| | - Fabrice Gonnot
- Univ-Lyon CarMeN Laboratory, Inserm U1060, Université Claude Bernard Lyon 1, INRAE, Bron, France
- Hospices Civils de Lyon, Groupement Hospitalier EST, Département de Cardiologie, IHU-OPERA Bâtiment B13, Bron, France
| | - Mariam Wehbi
- Univ-Lyon CarMeN Laboratory, Inserm U1060, Université Claude Bernard Lyon 1, INRAE, Bron, France
- Hospices Civils de Lyon, Groupement Hospitalier EST, Département de Cardiologie, IHU-OPERA Bâtiment B13, Bron, France
| | - Camille Brun
- Univ-Lyon CarMeN Laboratory, Inserm U1060, Université Claude Bernard Lyon 1, INRAE, Bron, France
- Hospices Civils de Lyon, Groupement Hospitalier EST, Département de Cardiologie, IHU-OPERA Bâtiment B13, Bron, France
| | - Ludovic Gomez
- Univ-Lyon CarMeN Laboratory, Inserm U1060, Université Claude Bernard Lyon 1, INRAE, Bron, France
- Hospices Civils de Lyon, Groupement Hospitalier EST, Département de Cardiologie, IHU-OPERA Bâtiment B13, Bron, France
| | - Gabriel Bidaux
- Univ-Lyon CarMeN Laboratory, Inserm U1060, Université Claude Bernard Lyon 1, INRAE, Bron, France
- Hospices Civils de Lyon, Groupement Hospitalier EST, Département de Cardiologie, IHU-OPERA Bâtiment B13, Bron, France
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5
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Sypniewski M, Szydlowski M. A Study of 41 Canine Orthologues of Human Genes Involved in Monogenic Obesity Reveals Marker in the ADCY3 for Body Weight in Labrador Retrievers. Vet Sci 2023; 10:390. [PMID: 37368776 DOI: 10.3390/vetsci10060390] [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: 04/07/2023] [Revised: 05/05/2023] [Accepted: 05/06/2023] [Indexed: 06/29/2023] Open
Abstract
Obesity and overweight are common conditions in dogs, but individual susceptibility varies with numerous risk factors, including diet, age, sterilization, and gender. In addition to environmental and biological factors, genetic and epigenetic risk factors can influence predisposition to canine obesity, however, they remain unknown. Labrador Retrievers are one of the breeds that are prone to obesity. The purpose of this study was to analyse 41 canine orthologues of human genes linked to monogenic obesity in humans to identify genes associated with body weight in Labrador Retriever dogs. We analysed 11,520 variants from 50 dogs using a linear mixed model with sex, age, and sterilization as covariates and population structure as a random effect. Estimates obtained from the model were subjected to a maxT permutation procedure to adjust p-values for FWER < 0.05. Only the ADCY3 gene showed statistically significant association: TA>T deletion located at 17:19,222,459 in 1/20 intron (per allele effect of 5.56 kg, SE 0.018, p-value = 5.83 × 10-5, TA/TA: 11 dogs; TA/T: 32 dogs; T/T: 7 dogs). Mutations in the ADCY3 gene have already been associated with obesity in mice and humans, making it a promising marker for canine obesity research. Our results provide further evidence that the genetic makeup of obesity in Labrador Retriever dogs contains genes with large effect sizes.
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Affiliation(s)
- Mateusz Sypniewski
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wołyńska 33, 60-637 Poznań, Poland
| | - Maciej Szydlowski
- Department of Genetics and Animal Breeding, Poznan University of Life Sciences, Wołyńska 33, 60-637 Poznań, Poland
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6
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Alonso MT, Torres-Vidal P, Calvo B, Rodriguez C, Delrio-Lorenzo A, Rojo-Ruiz J, Garcia-Sancho J, Patel S. Use of aequorin-based indicators for monitoring Ca 2+ in acidic organelles. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119481. [PMID: 37142127 DOI: 10.1016/j.bbamcr.2023.119481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/22/2023] [Accepted: 04/26/2023] [Indexed: 05/06/2023]
Abstract
Over the last years, there is accumulating evidence that acidic organelles can accumulate and release Ca2+ upon cell activation. Hence, reliable recording of Ca2+ dynamics in these compartments is essential for understanding the physiopathological aspects of acidic organelles. Genetically encoded Ca2+ indicators (GECIs) are valuable tools to monitor Ca2+ in specific locations, although their use in acidic compartments is challenging due to the pH sensitivity of most available fluorescent GECIs. By contrast, bioluminescent GECIs have a combination of features (marginal pH sensitivity, low background, no phototoxicity, no photobleaching, high dynamic range and tunable affinity) that render them advantageous to achieve an enhanced signal-to-noise ratio in acidic compartments. This article reviews the use of bioluminescent aequorin-based GECIs targeted to acidic compartments. A need for more measurements in highly acidic compartments is identified.
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Affiliation(s)
- M T Alonso
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain.
| | - P Torres-Vidal
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - B Calvo
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - C Rodriguez
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - A Delrio-Lorenzo
- Universidad Alfonso X el Sabio, Madrid, Avenida Universidad, 1, 28691 Villanueva de la Cañada, Madrid, Spain
| | - J Rojo-Ruiz
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - J Garcia-Sancho
- Unidad de Excelencia, Instituto de Biomedicina y Genética Molecular de Valladolid (IBGM), Universidad de Valladolid y Consejo Superior de Investigaciones Científicas (CSIC), c/ Sanz y Forés 3, 47003 Valladolid, Spain
| | - S Patel
- Department of Cell and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK
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7
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Harada K, Takashima M, Kitaguchi T, Tsuboi T. F-actin determines the time-dependent shift in docking dynamics of glucagon-like peptide-1 granules upon stimulation of secretion. FEBS Lett 2023; 597:657-671. [PMID: 36694275 DOI: 10.1002/1873-3468.14580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 01/09/2023] [Accepted: 01/09/2023] [Indexed: 01/26/2023]
Abstract
Although exocytosis can be categorized into several forms based on docking dynamics, temporal regulatory mechanisms of the exocytotic forms are unclear. We explored the dynamics of glucagon-like peptide-1 (GLP-1) exocytosis in murine GLUTag cells (GLP-1-secreting enteroendocrine L-cells) upon stimulation with deoxycholic acid (DCA) or high K+ to elucidate the mechanisms regulating the balance between the different types of exocytotic forms (pre-docked with the plasma membrane before stimulation; docked after stimulation and subsequently fused; or rapidly recruited and fused after stimulation, without stable docking). GLP-1 exocytosis showed a biphasic pattern, and we found that most exocytosis was from the pre-docked granules with the plasma membrane before stimulation, or granules rapidly fused to the plasma membrane without docking after stimulation. In contrast, granules docked with the plasma membrane after stimuli and eventually fused were predominant thereafter. Inhibition of actin polymerization suppressed exocytosis of the pre-docked granules. These results suggest that the docking dynamics of GLP-1 granules shows a time-dependent biphasic shift, which is determined by interaction with F-actin.
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Affiliation(s)
- Kazuki Harada
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan
| | - Maoko Takashima
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan
| | - Tetsuya Kitaguchi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Takashi Tsuboi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Japan
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8
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CD38–Cyclic ADP-Ribose Signal System in Physiology, Biochemistry, and Pathophysiology. Int J Mol Sci 2022; 23:ijms23084306. [PMID: 35457121 PMCID: PMC9033130 DOI: 10.3390/ijms23084306] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 04/02/2022] [Accepted: 04/12/2022] [Indexed: 11/16/2022] Open
Abstract
Calcium (Ca2+) is a ubiquitous and fundamental signaling component that is utilized by cells to regulate a diverse range of cellular functions, such as insulin secretion from pancreatic β-cells of the islets of Langerhans. Cyclic ADP-ribose (cADPR), synthesized from NAD+ by ADP-ribosyl cyclase family proteins, such as the mammalian cluster of differentiation 38 (CD38), is important for intracellular Ca2+ mobilization for cell functioning. cADPR induces Ca2+ release from endoplasmic reticulum via the ryanodine receptor intracellular Ca2+ channel complex, in which the FK506-binding protein 12.6 works as a cADPR-binding regulatory protein. Recently, involvements of the CD38-cADPR signal system in several human diseases and animal models have been reported. This review describes the biochemical and molecular biological basis of the CD38-cADPR signal system and the diseases caused by its abnormalities.
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9
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Roles of cADPR and NAADP in pancreatic beta cell signalling. Cell Calcium 2022; 103:102562. [DOI: 10.1016/j.ceca.2022.102562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 02/05/2022] [Accepted: 02/09/2022] [Indexed: 11/19/2022]
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10
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Han Y, Ding K. Imaging Neuropeptide Release at Drosophila Neuromuscular Junction with a Genetically Engineered Neuropeptide Release Reporter. Methods Mol Biol 2022; 2417:193-203. [PMID: 35099801 DOI: 10.1007/978-1-0716-1916-2_15] [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: 06/14/2023]
Abstract
Despite the important roles of neuropeptides in a variety of physiological processes, there still lacks a method to probe neuropeptide release events in vivo with satisfying temporal and spatial resolution. Neuropeptide Release Reporter (NPRR) was recently introduced as a novel genetically encoded indicator of neuropeptide release with a high temporal resolution and peptide specificity based on GCaMP molecule. Here we describe a method for using NPRR to image selective neuropeptide release at Drosophila neuromuscular junction in semi-dissected larvae. This method provides a quantitative analysis of activity-dependent neuropeptide release as real-time changes in fluorescence intensity of GCaMP reporter with sub-second temporal resolution and single bouton specificity.
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Affiliation(s)
- Yifu Han
- Department of Neurobiology, University of Southern California, Los Angeles, CA, USA.
- Neuroscience Graduate Program, University of Southern California, Los Angeles, CA, USA.
| | - Keke Ding
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
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11
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Germanos M, Gao A, Taper M, Yau B, Kebede MA. Inside the Insulin Secretory Granule. Metabolites 2021; 11:metabo11080515. [PMID: 34436456 PMCID: PMC8401130 DOI: 10.3390/metabo11080515] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/03/2021] [Accepted: 08/03/2021] [Indexed: 12/19/2022] Open
Abstract
The pancreatic β-cell is purpose-built for the production and secretion of insulin, the only hormone that can remove glucose from the bloodstream. Insulin is kept inside miniature membrane-bound storage compartments known as secretory granules (SGs), and these specialized organelles can readily fuse with the plasma membrane upon cellular stimulation to release insulin. Insulin is synthesized in the endoplasmic reticulum (ER) as a biologically inactive precursor, proinsulin, along with several other proteins that will also become members of the insulin SG. Their coordinated synthesis enables synchronized transit through the ER and Golgi apparatus for congregation at the trans-Golgi network, the initiating site of SG biogenesis. Here, proinsulin and its constituents enter the SG where conditions are optimized for proinsulin processing into insulin and subsequent insulin storage. A healthy β-cell is continually generating SGs to supply insulin in vast excess to what is secreted. Conversely, in type 2 diabetes (T2D), the inability of failing β-cells to secrete may be due to the limited biosynthesis of new insulin. Factors that drive the formation and maturation of SGs and thus the production of insulin are therefore critical for systemic glucose control. Here, we detail the formative hours of the insulin SG from the luminal perspective. We do this by mapping the journey of individual members of the SG as they contribute to its genesis.
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12
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Ježek P, Holendová B, Jabůrek M, Tauber J, Dlasková A, Plecitá-Hlavatá L. The Pancreatic β-Cell: The Perfect Redox System. Antioxidants (Basel) 2021; 10:antiox10020197. [PMID: 33572903 PMCID: PMC7912581 DOI: 10.3390/antiox10020197] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/20/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Pancreatic β-cell insulin secretion, which responds to various secretagogues and hormonal regulations, is reviewed here, emphasizing the fundamental redox signaling by NADPH oxidase 4- (NOX4-) mediated H2O2 production for glucose-stimulated insulin secretion (GSIS). There is a logical summation that integrates both metabolic plus redox homeostasis because the ATP-sensitive K+ channel (KATP) can only be closed when both ATP and H2O2 are elevated. Otherwise ATP would block KATP, while H2O2 would activate any of the redox-sensitive nonspecific calcium channels (NSCCs), such as TRPM2. Notably, a 100%-closed KATP ensemble is insufficient to reach the -50 mV threshold plasma membrane depolarization required for the activation of voltage-dependent Ca2+ channels. Open synergic NSCCs or Cl- channels have to act simultaneously to reach this threshold. The resulting intermittent cytosolic Ca2+-increases lead to the pulsatile exocytosis of insulin granule vesicles (IGVs). The incretin (e.g., GLP-1) amplification of GSIS stems from receptor signaling leading to activating the phosphorylation of TRPM channels and effects on other channels to intensify integral Ca2+-influx (fortified by endoplasmic reticulum Ca2+). ATP plus H2O2 are also required for branched-chain ketoacids (BCKAs); and partly for fatty acids (FAs) to secrete insulin, while BCKA or FA β-oxidation provide redox signaling from mitochondria, which proceeds by H2O2 diffusion or hypothetical SH relay via peroxiredoxin "redox kiss" to target proteins.
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13
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OKAMOTO H, TAKASAWA S. Okamoto model for necrosis and its expansions, CD38-cyclic ADP-ribose signal system for intracellular Ca 2+ mobilization and Reg (Regenerating gene protein)-Reg receptor system for cell regeneration. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2021; 97:423-461. [PMID: 34629354 PMCID: PMC8553518 DOI: 10.2183/pjab.97.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 06/22/2021] [Indexed: 05/03/2023]
Abstract
In pancreatic islet cell culture models and animal models, we studied the molecular mechanisms involved in the development of insulin-dependent diabetes. The diabetogenic agents, alloxan and streptozotocin, caused DNA strand breaks, which in turn activated poly(ADP-ribose) polymerase/synthetase (PARP) to deplete NAD+, thereby inhibiting islet β-cell functions such as proinsulin synthesis and ultimately leading to β-cell necrosis. Radical scavengers protected against the formation of DNA strand breaks and inhibition of proinsulin synthesis. Inhibitors of PARP prevented the NAD+ depletion, inhibition of proinsulin synthesis and β-cell death. These findings led to the proposed unifying concept for β-cell damage and its prevention (the Okamoto model). The model met one proof with PARP knockout animals and was further extended by the discovery of cyclic ADP-ribose as the second messenger for Ca2+ mobilization in glucose-induced insulin secretion and by the identification of Reg (Regenerating gene) for β-cell regeneration. Physiological and pathological events found in pancreatic β-cells have been observed in other cells and tissues.
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Affiliation(s)
- Hiroshi OKAMOTO
- Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Miyagi, Japan
- Department of Biochemistry and Molecular Vascular Biology, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Ishikawa, Japan
| | - Shin TAKASAWA
- Department of Biochemistry, Nara Medical University, Kashihara, Nara, Japan
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14
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Pratt EP, Anson KJ, Tapper JK, Simpson DM, Palmer AE. Systematic Comparison of Vesicular Targeting Signals Leads to the Development of Genetically Encoded Vesicular Fluorescent Zn 2+ and pH Sensors. ACS Sens 2020; 5:3879-3891. [PMID: 33305939 DOI: 10.1021/acssensors.0c01231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Genetically encoded fluorescent sensors have been widely used to illuminate secretory vesicle dynamics and the vesicular lumen, including Zn2+ and pH, in living cells. However, vesicular sensors have a tendency to mislocalize and are susceptible to the acidic intraluminal pH. In this study, we performed a systematic comparison of five different vesicular proteins to target the fluorescent protein mCherry and a Zn2+ Förster resonance energy transfer (FRET) sensor to secretory vesicles. We found that motifs derived from vesicular cargo proteins, including chromogranin A (CgA), target vesicular puncta with greater efficacy than transmembrane proteins. To characterize vesicular Zn2+ levels, we developed CgA-Zn2+ FRET sensor fusions with existing sensors ZapCY1 and eCALWY-4 and characterized subcellular localization and the influence of pH on sensor performance. We simultaneously monitored Zn2+ and pH in individual secretory vesicles by leveraging the acceptor fluorescent protein as a pH sensor and found that pH influenced FRET measurements in situ. While unable to characterize vesicular Zn2+ at the single-vesicle level, we were able to monitor Zn2+ dynamics in populations of vesicles and detected high vesicular Zn2+ in MIN6 cells compared to lower levels in the prostate cancer cell line LnCaP. The combination of CgA-ZapCY1 and CgA-eCALWY-4 allows for measurement of Zn2+ from pM to nM ranges.
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Affiliation(s)
- Evan P.S. Pratt
- Department of Biochemistry and BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, UCB 596, Boulder, Colorado 80309-0401, United States
| | - Kelsie J. Anson
- Department of Biochemistry and BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, UCB 596, Boulder, Colorado 80309-0401, United States
| | - Justin K. Tapper
- Department of Biochemistry and BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, UCB 596, Boulder, Colorado 80309-0401, United States
| | - David M. Simpson
- Department of Biochemistry and BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, UCB 596, Boulder, Colorado 80309-0401, United States
| | - Amy E. Palmer
- Department of Biochemistry and BioFrontiers Institute, University of Colorado Boulder, 3415 Colorado Ave, UCB 596, Boulder, Colorado 80309-0401, United States
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15
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Idevall-Hagren O, Tengholm A. Metabolic regulation of calcium signaling in beta cells. Semin Cell Dev Biol 2020; 103:20-30. [PMID: 32085965 DOI: 10.1016/j.semcdb.2020.01.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/10/2020] [Accepted: 01/28/2020] [Indexed: 12/22/2022]
Abstract
The cytoplasmic Ca2+ concentration ([Ca2+]cyt) regulates a vast number of cellular functions, including insulin secretion from beta cells. The major physiological insulin secretagogue, glucose, triggers [Ca2+]cyt oscillations in beta cells. Synchronization of the oscillations among the beta cells within an islet underlies the generation of pulsatile insulin secretion. This review describes the mechanisms generating [Ca2+]cyt oscillations, the interactions between [Ca2+]cyt and cell metabolism, as well as the contribution of various organelles to the shaping of [Ca2+]cyt signals and insulin secretion. It also discusses how Ca2+ signals are coordinated and spread throughout the islets and data indicating that altered Ca2+ signaling is associated with beta cell dysfunction and development of type 2 diabetes.
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Affiliation(s)
- Olof Idevall-Hagren
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23 Uppsala, Sweden
| | - Anders Tengholm
- Department of Medical Cell Biology, Uppsala University, Biomedical Centre, Box 571, SE-751 23 Uppsala, Sweden.
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16
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Ding K, Han Y, Seid TW, Buser C, Karigo T, Zhang S, Dickman DK, Anderson DJ. Imaging neuropeptide release at synapses with a genetically engineered reporter. eLife 2019; 8:e46421. [PMID: 31241464 PMCID: PMC6609332 DOI: 10.7554/elife.46421] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 06/25/2019] [Indexed: 12/26/2022] Open
Abstract
Research on neuropeptide function has advanced rapidly, yet there is still no spatio-temporally resolved method to measure the release of neuropeptides in vivo. Here we introduce Neuropeptide Release Reporters (NPRRs): novel genetically-encoded sensors with high temporal resolution and genetic specificity. Using the Drosophila larval neuromuscular junction (NMJ) as a model, we provide evidence that NPRRs recapitulate the trafficking and packaging of native neuropeptides, and report stimulation-evoked neuropeptide release events as real-time changes in fluorescence intensity, with sub-second temporal resolution.
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Affiliation(s)
- Keke Ding
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
| | - Yifu Han
- Department of NeurobiologyUniversity of Southern CaliforniaLos AngelesUnited States
- Neuroscience Graduate ProgramUniversity of Southern CaliforniaLos AngelesUnited States
| | - Taylor W Seid
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
| | | | - Tomomi Karigo
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
| | - Shishuo Zhang
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
| | - Dion K Dickman
- Department of NeurobiologyUniversity of Southern CaliforniaLos AngelesUnited States
| | - David J Anderson
- Division of Biology and Biological EngineeringCalifornia Institute of TechnologyPasadenaUnited States
- Howard Hughes Medical Institute, California Institute of TechnologyPasadenaUnited States
- Tianqiao and Chrissy Chen Institute for Neuroscience, California Institute of TechnologyPasadenaUnited States
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17
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High-Throughput Screening Using Photoluminescence Probe to Measure Intracellular Calcium Levels. Methods Mol Biol 2019; 1925:1-14. [PMID: 30674012 DOI: 10.1007/978-1-4939-9018-4_1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023]
Abstract
Aequorin, a 22 kDa protein produced by the jellyfish Aequorea victoria, was the first probe used to measure Ca2+ concentrations ([Ca2+]) of specific intracellular organelles in intact cells. After the binding of Ca2+ to three high-affinity binding sites, an irreversible reaction occurs leading to the emission of photons that is proportional to [Ca2+]. While native aequorin is suitable for measuring cytosolic [Ca2+] after cell stimulation in a range from 0.5 to 10 μM, it cannot be used in organelles where [Ca2+] is much higher, such as in the lumen of endoplasmic/sarcoplasmic reticulum (ER/SR) and mitochondria. However, some modifications made on aequorin itself or on coelenterazine, its lipophilic prosthetic luminophore, and the addition of targeting sequences or the fusion with resident proteins allowed the specific organelle localization and the measurements of intra-organelle Ca2+ levels. In the last years, the development of multiwell plate readers has opened the possibility to perform aequorin-based high-throughput screenings and has overcome some limitation of the standard method. Here we present the procedure for expressing, targeting, and reconstituting aequorin in intact cells and for measuring Ca2+ in the bulk cytosol, mitochondria, and ER by a high-throughput screening system.
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18
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Prole DL, Taylor CW. A genetically encoded toolkit of functionalized nanobodies against fluorescent proteins for visualizing and manipulating intracellular signalling. BMC Biol 2019; 17:41. [PMID: 31122229 PMCID: PMC6533734 DOI: 10.1186/s12915-019-0662-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 05/02/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Intrabodies enable targeting of proteins in live cells, but generating specific intrabodies against the thousands of proteins in a proteome poses a challenge. We leverage the widespread availability of fluorescently labelled proteins to visualize and manipulate intracellular signalling pathways in live cells by using nanobodies targeting fluorescent protein tags. RESULTS We generated a toolkit of plasmids encoding nanobodies against red and green fluorescent proteins (RFP and GFP variants), fused to functional modules. These include fluorescent sensors for visualization of Ca2+, H+ and ATP/ADP dynamics; oligomerising or heterodimerising modules that allow recruitment or sequestration of proteins and identification of membrane contact sites between organelles; SNAP tags that allow labelling with fluorescent dyes and targeted chromophore-assisted light inactivation; and nanobodies targeted to lumenal sub-compartments of the secretory pathway. We also developed two methods for crosslinking tagged proteins: a dimeric nanobody, and RFP-targeting and GFP-targeting nanobodies fused to complementary hetero-dimerizing domains. We show various applications of the toolkit and demonstrate, for example, that IP3 receptors deliver Ca2+ to the outer membrane of only a subset of mitochondria and that only one or two sites on a mitochondrion form membrane contacts with the plasma membrane. CONCLUSIONS This toolkit greatly expands the utility of intrabodies and will enable a range of approaches for studying and manipulating cell signalling in live cells.
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Affiliation(s)
- David L Prole
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK.
| | - Colin W Taylor
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK.
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19
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Yamamoto WR, Bone RN, Sohn P, Syed F, Reissaus CA, Mosley AL, Wijeratne AB, True JD, Tong X, Kono T, Evans-Molina C. Endoplasmic reticulum stress alters ryanodine receptor function in the murine pancreatic β cell. J Biol Chem 2019; 294:168-181. [PMID: 30420428 PMCID: PMC6322901 DOI: 10.1074/jbc.ra118.005683] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 11/08/2018] [Indexed: 01/23/2023] Open
Abstract
Alterations in endoplasmic reticulum (ER) calcium (Ca2+) levels diminish insulin secretion and reduce β-cell survival in both major forms of diabetes. The mechanisms responsible for ER Ca2+ loss in β cells remain incompletely understood. Moreover, a specific role for either ryanodine receptor (RyR) or inositol 1,4,5-triphosphate receptor (IP3R) dysfunction in the pathophysiology of diabetes remains largely untested. To this end, here we applied intracellular and ER Ca2+ imaging techniques in INS-1 β cells and isolated islets to determine whether diabetogenic stressors alter RyR or IP3R function. Our results revealed that the RyR is sensitive mainly to ER stress-induced dysfunction, whereas cytokine stress specifically alters IP3R activity. Consistent with this observation, pharmacological inhibition of the RyR with ryanodine and inhibition of the IP3R with xestospongin C prevented ER Ca2+ loss under ER and cytokine stress conditions, respectively. However, RyR blockade distinctly prevented β-cell death, propagation of the unfolded protein response (UPR), and dysfunctional glucose-induced Ca2+ oscillations in tunicamycin-treated INS-1 β cells and mouse islets and Akita islets. Monitoring at the single-cell level revealed that ER stress acutely increases the frequency of intracellular Ca2+ transients that depend on both ER Ca2+ leakage from the RyR and plasma membrane depolarization. Collectively, these findings indicate that RyR dysfunction shapes ER Ca2+ dynamics in β cells and regulates both UPR activation and cell death, suggesting that RyR-mediated loss of ER Ca2+ may be an early pathogenic event in diabetes.
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Affiliation(s)
- Wataru R Yamamoto
- Departments of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Robert N Bone
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Paul Sohn
- Departments of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Farooq Syed
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Christopher A Reissaus
- Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Amber L Mosley
- Departments of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Aruna B Wijeratne
- Departments of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Jason D True
- Departments of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Xin Tong
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee 37235
| | - Tatsuyoshi Kono
- Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Carmella Evans-Molina
- Departments of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202; Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana 46202; Departments of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana 46202; Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana 46202; Roudebush Veterans Affairs Medical Center, Indianapolis, Indiana 46202.
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20
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The Trans Golgi Region is a Labile Intracellular Ca 2+ Store Sensitive to Emetine. Sci Rep 2018; 8:17143. [PMID: 30464185 PMCID: PMC6249204 DOI: 10.1038/s41598-018-35280-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 09/10/2018] [Indexed: 01/22/2023] Open
Abstract
The Golgi apparatus (GA) is a bona fide Ca2+ store; however, there is a lack of GA-specific Ca2+ mobilizing agents. Here, we report that emetine specifically releases Ca2+ from GA in HeLa and HL-1 atrial myocytes. Additionally, it has become evident that the trans-Golgi is a labile Ca2+ store that requires a continuous source of Ca2+ from either the external milieu or from the ER, to enable it to produce a detectable transient increase in cytosolic Ca2+. Our data indicates that the emetine-sensitive Ca2+ mobilizing mechanism is different from the two classical Ca2+ release mechanisms, i.e. IP3 and ryanodine receptors. This newly discovered ability of emetine to release Ca2+ from the GA may explain why chronic consumption of ipecac syrup has muscle side effects.
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21
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Betzer C, Jensen PH. Reduced Cytosolic Calcium as an Early Decisive Cellular State in Parkinson's Disease and Synucleinopathies. Front Neurosci 2018; 12:819. [PMID: 30459551 PMCID: PMC6232531 DOI: 10.3389/fnins.2018.00819] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/19/2018] [Indexed: 12/26/2022] Open
Abstract
The more than 30-year-old Calcium hypothesis postulates that dysregulation in calcium dependent processes in the aging brain contributes to its increased vulnerability and this concept has been extended to Alzheimer’s disease and Parkinson’s disease. Central to the hypothesis is that increased levels of intracellular calcium develop and contributes to neuronal demise. We have studied the impact on cells encountering a gradual build-up of aggregated α-synuclein, which is a central process to Parkinson’s disease and other synucleinopathies. Surprisingly, we observed a yet unrecognized phase characterized by a reduced cytosolic calcium in cellular and neuronal models of Parkinson’s disease, caused by α-synuclein aggregates activating the endoplasmic calcium ATPase, SERCA. Counteracting the initial phase with low calcium rescues the subsequent degenerative phase with increased calcium and cell death – and demonstrates this early phase initiates decisive degenerative signals. In this review, we discuss our findings in relation to literature on calcium dysregulation in Parkinson’s disease and dementia.
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Affiliation(s)
- Cristine Betzer
- DANDRITE - Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Poul Henning Jensen
- DANDRITE - Danish Research Institute of Translational Neuroscience, Aarhus University, Aarhus, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
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22
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Rodríguez MA, Martínez-Higuera A, Valle-Solis MI, Hernandes-Alejandro M, Chávez-Munguía B, Figueroa-Gutiérrez AH, Salas-Casas A. A putative calcium-ATPase of the secretory pathway family may regulate calcium/manganese levels in the Golgi apparatus of Entamoeba histolytica. Parasitol Res 2018; 117:3381-3389. [PMID: 30084034 DOI: 10.1007/s00436-018-6030-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 07/25/2018] [Indexed: 01/01/2023]
Abstract
Calcium regulates many cellular processes in protozoa, including growth, differentiation, programmed cell death, exocytosis, endocytosis, phagocytosis, fusion of the endosomes of distinct stages with phagosomes, fusion of phagosomes with lysosomes, and recycling the membrane. In Entamoeba histolytica, the protozoa responsible for human amoebiasis, calcium ions are essential for signaling pathways that lead to growth and development. In addition, calcium is crucial in the modulation of gene expression in this microorganism. However, there is scant information about the proteins responsible for regulating calcium levels in this parasite. In this work, we characterized a protein of E. histolytica that shows a close phylogenetic relationship with Ca2+ pumps that belong to the family of secretory pathway calcium ATPases (SPCA), which for several organisms are located in the Golgi apparatus. The amoeba protein analyzed herein has several amino acid residues that are characteristic of SPCA members. By an immunofluorescent technique using specific antibodies and immunoelectron microscopy, the protein was detected on the membrane of some cytoplasmic vacuoles. Moreover, this putative calcium-ATPase was located in vacuoles stained with NBD C6-ceramide, a Golgi marker. Overall, the current findings support the hypothesis that the presently analyzed protein corresponds to the SPCA of E. histolytica.
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Affiliation(s)
- Mario A Rodríguez
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | | | - Martha I Valle-Solis
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | - Mario Hernandes-Alejandro
- Departamento de Bioingeniería, Unidad Profesional Interdisciplinaria de Biotecnología del Instituto Politécnico Nacional (UPIBI-IPN), Mexico City, Mexico
| | - Bibiana Chávez-Munguía
- Departamento de Infectómica y Patogénesis Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Mexico City, Mexico
| | - Ana H Figueroa-Gutiérrez
- Instituto de Ciencias de la Salud, Área Académica de Gerontología, Universidad Autónoma del Estado de Hidalgo, Ex Hacienda la Concepción, s/n; Carretera Actopan-Tilcuautla, San Agustín Tlaxiaca, Hidalgo, Mexico
| | - Andrés Salas-Casas
- Instituto de Ciencias de la Salud, Área Académica de Gerontología, Universidad Autónoma del Estado de Hidalgo, Ex Hacienda la Concepción, s/n; Carretera Actopan-Tilcuautla, San Agustín Tlaxiaca, Hidalgo, Mexico.
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23
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Shinoda H, Shannon M, Nagai T. Fluorescent Proteins for Investigating Biological Events in Acidic Environments. Int J Mol Sci 2018; 19:E1548. [PMID: 29789517 PMCID: PMC6032295 DOI: 10.3390/ijms19061548] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 05/18/2018] [Accepted: 05/19/2018] [Indexed: 12/11/2022] Open
Abstract
The interior lumen of acidic organelles (e.g., endosomes, secretory granules, lysosomes and plant vacuoles) is an important platform for modification, transport and degradation of biomolecules as well as signal transduction, which remains challenging to investigate using conventional fluorescent proteins (FPs). Due to the highly acidic luminal environment (pH ~ 4.5⁻6.0), most FPs and related sensors are apt to lose their fluorescence. To address the need to image in acidic environments, several research groups have developed acid-tolerant FPs in a wide color range. Furthermore, the engineering of pH insensitive sensors, and their concomitant use with pH sensitive sensors for the purpose of pH-calibration has enabled characterization of the role of luminal ions. In this short review, we summarize the recent development of acid-tolerant FPs and related functional sensors and discuss the future prospects for this field.
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Affiliation(s)
- Hajime Shinoda
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan.
| | - Michael Shannon
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan.
| | - Takeharu Nagai
- Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita 565-0871, Japan.
- The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki 567-0047, Japan.
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24
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Rutter GA, Hodson DJ, Chabosseau P, Haythorne E, Pullen TJ, Leclerc I. Local and regional control of calcium dynamics in the pancreatic islet. Diabetes Obes Metab 2017; 19 Suppl 1:30-41. [PMID: 28466490 DOI: 10.1111/dom.12990] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/19/2017] [Accepted: 04/24/2017] [Indexed: 12/31/2022]
Abstract
Ca2+ is the key intracellular regulator of insulin secretion, acting in the β-cell as the ultimate trigger for exocytosis. In response to high glucose, ATP-sensitive K+ channel closure and plasma membrane depolarization engage a sophisticated machinery to drive pulsatile cytosolic Ca2+ changes. Voltage-gated Ca2+ channels, Ca2+ -activated K+ channels and Na+ /Ca2+ exchange all play important roles. The use of targeted Ca2+ probes has revealed that during each cytosolic Ca2+ pulse, uptake of Ca2+ by mitochondria, endoplasmic reticulum (ER), secretory granules and lysosomes fine-tune cytosolic Ca2+ dynamics and control organellar function. For example, changes in the expression of the Ca2+ -binding protein Sorcin appear to provide a link between ER Ca2+ levels and ER stress, affecting β-cell function and survival. Across the islet, intercellular communication between highly interconnected "hubs," which act as pacemaker β-cells, and subservient "followers," ensures efficient insulin secretion. Loss of connectivity is seen after the deletion of genes associated with type 2 diabetes (T2D) and follows metabolic and inflammatory insults that characterize this disease. Hubs, which typically comprise ~1%-10% of total β-cells, are repurposed for their specialized role by expression of high glucokinase (Gck) but lower Pdx1 and Nkx6.1 levels. Single cell-omics are poised to provide a deeper understanding of the nature of these cells and of the networks through which they communicate. New insights into the control of both the intra- and intercellular Ca2+ dynamics may thus shed light on T2D pathology and provide novel opportunities for therapy.
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Affiliation(s)
- Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Edgbaston, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, COMPARE University of Birmingham and University of Nottingham Midlands, Birmingham, UK
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
| | - Elizabeth Haythorne
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
| | - Timothy J Pullen
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, and the Imperial Pancreatic Islet Biology and Diabetes Consortium, Hammersmith Hospital, Imperial College London, London, UK
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25
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Molecular regulation of insulin granule biogenesis and exocytosis. Biochem J 2017; 473:2737-56. [PMID: 27621482 DOI: 10.1042/bcj20160291] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 04/19/2016] [Indexed: 12/15/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by hyperglycemia, insulin resistance and hyperinsulinemia in early disease stages but a relative insulin insufficiency in later stages. Insulin, a peptide hormone, is produced in and secreted from pancreatic β-cells following elevated blood glucose levels. Upon its release, insulin induces the removal of excessive exogenous glucose from the bloodstream primarily by stimulating glucose uptake into insulin-dependent tissues as well as promoting hepatic glycogenesis. Given the increasing prevalence of T2DM worldwide, elucidating the underlying mechanisms and identifying the various players involved in the synthesis and exocytosis of insulin from β-cells is of utmost importance. This review summarizes our current understanding of the route insulin takes through the cell after its synthesis in the endoplasmic reticulum as well as our knowledge of the highly elaborate network that controls insulin release from the β-cell. This network harbors potential targets for anti-diabetic drugs and is regulated by signaling cascades from several endocrine systems.
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26
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Alonso MT, Rodríguez-Prados M, Navas-Navarro P, Rojo-Ruiz J, García-Sancho J. Using aequorin probes to measure Ca 2+ in intracellular organelles. Cell Calcium 2017; 64:3-11. [PMID: 28214023 DOI: 10.1016/j.ceca.2017.01.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 01/11/2017] [Indexed: 11/28/2022]
Abstract
Aequorins are excellent tools for measuring intra-organellar Ca2+ and assessing its role in physiological and pathological functions. Here we review targeting strategies to express aequorins in various organelles. We address critical topics such as probe affinity tuning as well as normalization and calibration of the signal. We also focus on bioluminescent Ca2+ imaging in nucleus or mitochondria of living cells. Finally, recent advances with a new chimeric GFP-aequorin protein (GAP), which can be used either as luminescent or fluorescent Ca2+ probe, are presented. GAP is robustly expressed in transgenic flies and mice, where it has proven to be a suitable Ca2+ indicator for monitoring physiological Ca2+ signaling ex vivo and in vivo.
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Affiliation(s)
- María Teresa Alonso
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain.
| | - Macarena Rodríguez-Prados
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain
| | - Paloma Navas-Navarro
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain
| | - Jonathan Rojo-Ruiz
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain
| | - Javier García-Sancho
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), c/Sanz y Forés 3, 47003 Valladolid, Spain.
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27
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Pendin D, Greotti E, Lefkimmiatis K, Pozzan T. Exploring cells with targeted biosensors. J Gen Physiol 2016; 149:1-36. [PMID: 28028123 PMCID: PMC5217087 DOI: 10.1085/jgp.201611654] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/26/2016] [Accepted: 12/01/2016] [Indexed: 01/10/2023] Open
Abstract
Cellular signaling networks are composed of multiple pathways, often interconnected, that form complex networks with great potential for cross-talk. Signal decoding depends on the nature of the message as well as its amplitude, temporal pattern, and spatial distribution. In addition, the existence of membrane-bound organelles, which are both targets and generators of messages, add further complexity to the system. The availability of sensors that can localize to specific compartments in live cells and monitor their targets with high spatial and temporal resolution is thus crucial for a better understanding of cell pathophysiology. For this reason, over the last four decades, a variety of strategies have been developed, not only to generate novel and more sensitive probes for ions, metabolites, and enzymatic activity, but also to selectively deliver these sensors to specific intracellular compartments. In this review, we summarize the principles that have been used to target organic or protein sensors to different cellular compartments and their application to cellular signaling.
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Affiliation(s)
- Diana Pendin
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Elisa Greotti
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
| | - Konstantinos Lefkimmiatis
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Venetian Institute of Molecular Medicine, 35129 Padua, Italy
| | - Tullio Pozzan
- Neuroscience Institute, National Research Council, Padua Section, 35121 Padua, Italy.,Venetian Institute of Molecular Medicine, 35129 Padua, Italy.,Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
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28
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Alonso MT, Rojo-Ruiz J, Navas-Navarro P, Rodríguez-Prados M, García-Sancho J. Measuring Ca 2+ inside intracellular organelles with luminescent and fluorescent aequorin-based sensors. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1864:894-899. [PMID: 27939433 DOI: 10.1016/j.bbamcr.2016.12.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 12/05/2016] [Accepted: 12/06/2016] [Indexed: 02/06/2023]
Abstract
GFP-Aequorin Protein (GAP) can be used to measure [Ca2+] inside intracellular organelles, both by luminescence and by fluorescence. The low-affinity variant GAP3 is adequate for ratiometric imaging in the endoplasmic reticulum and Golgi apparatus, and it can be combined with conventional synthetic indicators for simultaneous measurements of cytosolic Ca2+. GAP is bioorthogonal as it does not have mammalian homologues, and it is robust and functionally expressed in transgenic flies and mice, where it can be used for Ca2+ measurements ex vivo and in vivo to explore animal models of health and disease. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.
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Affiliation(s)
- María Teresa Alonso
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain.
| | - Jonathan Rojo-Ruiz
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain
| | - Paloma Navas-Navarro
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain
| | - Macarena Rodríguez-Prados
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain
| | - Javier García-Sancho
- Instituto de Biología y Genética Molecular (IBGM), Universidad de Valladolid and Consejo Superior de Investigaciones Científicas (CSIC), C/Sanz y Forés 3, 47003, Valladolid, Spain.
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29
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Shang S, Zhu F, Liu B, Chai Z, Wu Q, Hu M, Wang Y, Huang R, Zhang X, Wu X, Sun L, Wang Y, Wang L, Xu H, Teng S, Liu B, Zheng L, Zhang C, Zhang F, Feng X, Zhu D, Wang C, Liu T, Zhu MX, Zhou Z. Intracellular TRPA1 mediates Ca2+ release from lysosomes in dorsal root ganglion neurons. J Cell Biol 2016; 215:369-381. [PMID: 27799370 PMCID: PMC5100290 DOI: 10.1083/jcb.201603081] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 08/16/2016] [Accepted: 10/04/2016] [Indexed: 11/22/2022] Open
Abstract
Transient receptor potential A1 (TRPA1) is a nonselective cation channel implicated in thermosensation and inflammatory pain. In this study, we show that TRPA1 (activated by allyl isothiocyanate, acrolein, and 4-hydroxynonenal) elevates the intracellular Ca2+ concentration ([Ca2+]i) in dorsal root ganglion (DRG) neurons in the presence and absence of extracellular Ca2+ Pharmacological and immunocytochemical analyses revealed the presence of TRPA1 channels both on the plasma membrane and in endolysosomes. Confocal line-scan imaging demonstrated Ca2+ signals elicited from individual endolysosomes ("lysosome Ca2+ sparks") by TRPA1 activation. In physiological solutions, the TRPA1-mediated endolysosomal Ca2+ release contributed to ∼40% of the overall [Ca2+]i rise and directly triggered vesicle exocytosis and calcitonin gene-related peptide release, which greatly enhanced the excitability of DRG neurons. Thus, in addition to working via Ca2+ influx, TRPA1 channels trigger vesicle release in sensory neurons by releasing Ca2+ from lysosome-like organelles.
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Affiliation(s)
- Shujiang Shang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China.,Laboratory Animal Center, Peking University, Beijing 100871, China.,School of Life Science, Peking University, Beijing 100871, China
| | - Feipeng Zhu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Bin Liu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Zuying Chai
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Qihui Wu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Meiqin Hu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Yuan Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Rong Huang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Xiaoyu Zhang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Xi Wu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Lei Sun
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Yeshi Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Li Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Huadong Xu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Sasa Teng
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Bing Liu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Lianghong Zheng
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Chen Zhang
- School of Life Science, Peking University, Beijing 100871, China
| | - Fukang Zhang
- Institute for Biomedical Science of Pain, Capital Medical University, Beijing 100069, China
| | - Xinghua Feng
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - Desheng Zhu
- Laboratory Animal Center, Peking University, Beijing 100871, China
| | - Changhe Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Tao Liu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
| | - Michael X Zhu
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030
| | - Zhuan Zhou
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine and Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing 100871, China
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30
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Doghman-Bouguerra M, Granatiero V, Sbiera S, Sbiera I, Lacas-Gervais S, Brau F, Fassnacht M, Rizzuto R, Lalli E. FATE1 antagonizes calcium- and drug-induced apoptosis by uncoupling ER and mitochondria. EMBO Rep 2016; 17:1264-80. [PMID: 27402544 PMCID: PMC5007562 DOI: 10.15252/embr.201541504] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 06/10/2016] [Accepted: 06/16/2016] [Indexed: 11/09/2022] Open
Abstract
Several stimuli induce programmed cell death by increasing Ca(2+) transfer from the endoplasmic reticulum (ER) to mitochondria. Perturbation of this process has a special relevance in pathologies as cancer and neurodegenerative disorders. Mitochondrial Ca(2+) uptake mainly takes place in correspondence of mitochondria-associated ER membranes (MAM), specialized contact sites between the two organelles. Here, we show the important role of FATE1, a cancer-testis antigen, in the regulation of ER-mitochondria distance and Ca(2+) uptake by mitochondria. FATE1 is localized at the interface between ER and mitochondria, fractionating into MAM FATE1 expression in adrenocortical carcinoma (ACC) cells under the control of the transcription factor SF-1 decreases ER-mitochondria contact and mitochondrial Ca(2+) uptake, while its knockdown has an opposite effect. FATE1 also decreases sensitivity to mitochondrial Ca(2+)-dependent pro-apoptotic stimuli and to the chemotherapeutic drug mitotane. In patients with ACC, FATE1 expression in their tumor is inversely correlated with their overall survival. These results show that the ER-mitochondria uncoupling activity of FATE1 is harnessed by cancer cells to escape apoptotic death and resist the action of chemotherapeutic drugs.
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Affiliation(s)
- Mabrouka Doghman-Bouguerra
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275 Sophia Antipolis, Valbonne, France NEOGENEX CNRS International Associated Laboratory, Valbonne, France University of Nice - Sophia Antipolis, Valbonne, France
| | - Veronica Granatiero
- Department of Biomedical Sciences, University of Padova, Padova, Italy CNR Neuroscience Institute, Padova, Italy
| | - Silviu Sbiera
- Department of Internal Medicine I - Endocrine Unit, University Hospital University of Würzburg, Würzburg, Germany
| | - Iuliu Sbiera
- Department of Internal Medicine I - Endocrine Unit, University Hospital University of Würzburg, Würzburg, Germany
| | | | - Frédéric Brau
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275 Sophia Antipolis, Valbonne, France University of Nice - Sophia Antipolis, Valbonne, France
| | - Martin Fassnacht
- Comprehensive Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany
| | - Rosario Rizzuto
- Department of Biomedical Sciences, University of Padova, Padova, Italy CNR Neuroscience Institute, Padova, Italy
| | - Enzo Lalli
- Institut de Pharmacologie Moléculaire et Cellulaire CNRS UMR 7275 Sophia Antipolis, Valbonne, France NEOGENEX CNRS International Associated Laboratory, Valbonne, France University of Nice - Sophia Antipolis, Valbonne, France
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31
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Silva PN, Atto Z, Regeenes R, Tufa U, Chen YY, Chan WCW, Volchuk A, Kilkenny DM, Rocheleau JV. Highly efficient adenoviral transduction of pancreatic islets using a microfluidic device. LAB ON A CHIP 2016; 16:2921-2934. [PMID: 27378588 DOI: 10.1039/c6lc00345a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Tissues are challenging to genetically manipulate due to limited penetration of viral particles resulting in low transduction efficiency. We are particularly interested in expressing genetically-encoded sensors in ex vivo pancreatic islets to measure glucose-stimulated metabolism, however poor viral penetration biases these measurements to only a subset of cells at the periphery. To increase mass transfer of viral particles, we designed a microfluidic device that holds islets in parallel hydrodynamic traps connected by an expanding by-pass channel. We modeled viral particle flow into the tissue using fluorescently-labelled gold nanoparticles of varying sizes and showed a penetration threshold of only ∼5 nm. To increase this threshold, we used EDTA to transiently reduce cell-cell adhesion and expand intercellular space. Ultimately, a combination of media flow and ETDA treatment significantly increased adenoviral transduction to the core of the islet. As proof-of-principle, we used this protocol to transduce an ER-targeted redox sensitive sensor (eroGFP), and revealed significantly greater ER redox capacity at core islet cells. Overall, these data demonstrate a robust method to enhance transduction efficiency of islets, and potentially other tissues, by using a combination of microfluidic flow and transient tissue expansion.
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Affiliation(s)
- Pamuditha N Silva
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada.
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32
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Marmugi A, Parnis J, Chen X, Carmichael L, Hardy J, Mannan N, Marchetti P, Piemonti L, Bosco D, Johnson P, Shapiro JAM, Cruciani-Guglielmacci C, Magnan C, Ibberson M, Thorens B, Valdivia HH, Rutter GA, Leclerc I. Sorcin Links Pancreatic β-Cell Lipotoxicity to ER Ca2+ Stores. Diabetes 2016; 65:1009-21. [PMID: 26822088 PMCID: PMC4806657 DOI: 10.2337/db15-1334] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/18/2016] [Indexed: 01/02/2023]
Abstract
Preserving β-cell function during the development of obesity and insulin resistance would limit the worldwide epidemic of type 2 diabetes. Endoplasmic reticulum (ER) calcium (Ca(2+)) depletion induced by saturated free fatty acids and cytokines causes β-cell ER stress and apoptosis, but the molecular mechanisms behind these phenomena are still poorly understood. Here, we demonstrate that palmitate-induced sorcin downregulation and subsequent increases in glucose-6-phosphatase catalytic subunit-2 (G6PC2) levels contribute to lipotoxicity. Sorcin is a calcium sensor protein involved in maintaining ER Ca(2+) by inhibiting ryanodine receptor activity and playing a role in terminating Ca(2+)-induced Ca(2+) release. G6PC2, a genome-wide association study gene associated with fasting blood glucose, is a negative regulator of glucose-stimulated insulin secretion (GSIS). High-fat feeding in mice and chronic exposure of human islets to palmitate decreases endogenous sorcin expression while levels of G6PC2 mRNA increase. Sorcin-null mice are glucose intolerant, with markedly impaired GSIS and increased expression of G6pc2 Under high-fat diet, mice overexpressing sorcin in the β-cell display improved glucose tolerance, fasting blood glucose, and GSIS, whereas G6PC2 levels are decreased and cytosolic and ER Ca(2+) are increased in transgenic islets. Sorcin may thus provide a target for intervention in type 2 diabetes.
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Affiliation(s)
- Alice Marmugi
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Julia Parnis
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Xi Chen
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI
| | - LeAnne Carmichael
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Julie Hardy
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Naila Mannan
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K
| | - Piero Marchetti
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - Lorenzo Piemonti
- Diabetes Research Institute (HSR-DRI), San Raffaele Scientific Institute, Milan, Italy
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Paul Johnson
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, U.K
| | - James A M Shapiro
- Clinical Islet Laboratory and Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada
| | | | - Christophe Magnan
- Unit of Functional and Adaptive Biology, Paris Diderot University-Paris 7, Paris, France
| | - Mark Ibberson
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Héctor H Valdivia
- Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K.
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Imperial College London, London, U.K.
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33
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Hessels AM, Chabosseau P, Bakker MH, Engelen W, Rutter GA, Taylor KM, Merkx M. eZinCh-2: A Versatile, Genetically Encoded FRET Sensor for Cytosolic and Intraorganelle Zn(2+) Imaging. ACS Chem Biol 2015; 10:2126-34. [PMID: 26151333 PMCID: PMC4577962 DOI: 10.1021/acschembio.5b00211] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Zn(2+) plays essential and diverse roles in numerous cellular processes. To get a better understanding of intracellular Zn(2+) homeostasis and the putative signaling role of Zn(2+), various fluorescent sensors have been developed that allow monitoring of Zn(2+) concentrations in single living cells in real time. Thus far, two families of genetically encoded FRET-based Zn(2+) sensors have been most widely applied, the eCALWY sensors developed by our group and the ZapCY sensors developed by Palmer and co-workers. Both have been successfully used to measure cytosolic free Zn(2+), but distinctly different concentrations have been reported when using these sensors to measure Zn(2+) concentrations in the ER and mitochondria. Here, we report the development of a versatile alternative FRET sensor containing a de novo Cys2His2 binding pocket that was created on the surface of the donor and acceptor fluorescent domains. This eZinCh-2 sensor binds Zn(2+) with a high affinity that is similar to that of eCALWY-4 (Kd = 1 nM at pH 7.1), while displaying a substantially larger change in emission ratio. eZinCh-2 not only provides an attractive alternative for measuring Zn(2+) in the cytosol but was also successfully used for measuring Zn(2+) in the ER, mitochondria, and secretory vesicles. Moreover, organelle-targeted eZinCh-2 can also be used in combination with the previously reported redCALWY sensors to allow multicolor imaging of intracellular Zn(2+) simultaneously in the cytosol and the ER or mitochondria.
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Affiliation(s)
- Anne M. Hessels
- Laboratory
of Chemical Biology and Institute of Complex Molecular Systems (ICMS),
Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Pauline Chabosseau
- Section
of Cell Biology and Functional Genomics, Division of Medicine, Imperial College London, London, United Kingdom
| | - Maarten H. Bakker
- Laboratory
of Chemical Biology and Institute of Complex Molecular Systems (ICMS),
Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Wouter Engelen
- Laboratory
of Chemical Biology and Institute of Complex Molecular Systems (ICMS),
Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Guy A. Rutter
- Section
of Cell Biology and Functional Genomics, Division of Medicine, Imperial College London, London, United Kingdom
| | - Kathryn M. Taylor
- Breast
Cancer Molecular Pharmacology Group, School of Pharmacy and Pharmaceutical
Sciences, Cardiff University, Cardiff, United Kingdom
| | - Maarten Merkx
- Laboratory
of Chemical Biology and Institute of Complex Molecular Systems (ICMS),
Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
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34
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Arredouani A, Ruas M, Collins SC, Parkesh R, Clough F, Pillinger T, Coltart G, Rietdorf K, Royle A, Johnson P, Braun M, Zhang Q, Sones W, Shimomura K, Morgan AJ, Lewis AM, Chuang KT, Tunn R, Gadea J, Teboul L, Heister PM, Tynan PW, Bellomo EA, Rutter GA, Rorsman P, Churchill GC, Parrington J, Galione A. Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) and Endolysosomal Two-pore Channels Modulate Membrane Excitability and Stimulus-Secretion Coupling in Mouse Pancreatic β Cells. J Biol Chem 2015; 290:21376-92. [PMID: 26152717 PMCID: PMC4571866 DOI: 10.1074/jbc.m115.671248] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Indexed: 12/02/2022] Open
Abstract
Pancreatic β cells are electrically excitable and respond to elevated glucose concentrations with bursts of Ca2+ action potentials due to the activation of voltage-dependent Ca2+ channels (VDCCs), which leads to the exocytosis of insulin granules. We have examined the possible role of nicotinic acid adenine dinucleotide phosphate (NAADP)-mediated Ca2+ release from intracellular stores during stimulus-secretion coupling in primary mouse pancreatic β cells. NAADP-regulated Ca2+ release channels, likely two-pore channels (TPCs), have recently been shown to be a major mechanism for mobilizing Ca2+ from the endolysosomal system, resulting in localized Ca2+ signals. We show here that NAADP-mediated Ca2+ release from endolysosomal Ca2+ stores activates inward membrane currents and depolarizes the β cell to the threshold for VDCC activation and thereby contributes to glucose-evoked depolarization of the membrane potential during stimulus-response coupling. Selective pharmacological inhibition of NAADP-evoked Ca2+ release or genetic ablation of endolysosomal TPC1 or TPC2 channels attenuates glucose- and sulfonylurea-induced membrane currents, depolarization, cytoplasmic Ca2+ signals, and insulin secretion. Our findings implicate NAADP-evoked Ca2+ release from acidic Ca2+ storage organelles in stimulus-secretion coupling in β cells.
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Affiliation(s)
- Abdelilah Arredouani
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom,
| | - Margarida Ruas
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Stephan C Collins
- the Centre des Sciences du Gout et de l'Alimentation, Equipe 5, 9E Boulevard Jeanne d'Arc 21000 Dijon, France
| | - Raman Parkesh
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Frederick Clough
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Toby Pillinger
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - George Coltart
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Katja Rietdorf
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Andrew Royle
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Paul Johnson
- the Nuffield Department of Surgery, John Radcliffe Hospital, Headley Way, Headington, Oxford OX3 9DU, United Kingdom
| | - Matthias Braun
- the The Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
| | - Quan Zhang
- the The Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
| | - William Sones
- the The Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
| | - Kenju Shimomura
- the Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy, and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, United Kingdom
| | - Anthony J Morgan
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Alexander M Lewis
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Kai-Ting Chuang
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Ruth Tunn
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Joaquin Gadea
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Lydia Teboul
- The Mary Lyon Centre, Medical Research Council Harwell, Oxfordshire OX11 0RD, United Kingdom
| | - Paula M Heister
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Patricia W Tynan
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - Elisa A Bellomo
- the Centre des Sciences du Gout et de l'Alimentation, Equipe 5, 9E Boulevard Jeanne d'Arc 21000 Dijon, France
| | - Guy A Rutter
- the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Medicine, Imperial College London, Hammersmith Hospital, du Cane Road, London W12 0NN, United Kingdom, and
| | - Patrik Rorsman
- the The Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, United Kingdom
| | - Grant C Churchill
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom
| | - John Parrington
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom,
| | - Antony Galione
- From the Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, United Kingdom,
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Llanos P, Contreras-Ferrat A, Barrientos G, Valencia M, Mears D, Hidalgo C. Glucose-Dependent Insulin Secretion in Pancreatic β-Cell Islets from Male Rats Requires Ca2+ Release via ROS-Stimulated Ryanodine Receptors. PLoS One 2015; 10:e0129238. [PMID: 26046640 PMCID: PMC4457734 DOI: 10.1371/journal.pone.0129238] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 05/06/2015] [Indexed: 12/03/2022] Open
Abstract
Glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells requires an increase in intracellular free Ca2+ concentration ([Ca2+]). Glucose uptake into β-cells promotes Ca2+ influx and reactive oxygen species (ROS) generation. In other cell types, Ca2+ and ROS jointly induce Ca2+ release mediated by ryanodine receptor (RyR) channels. Therefore, we explored here if RyR-mediated Ca2+ release contributes to GSIS in β-cell islets isolated from male rats. Stimulatory glucose increased islet insulin secretion, and promoted ROS generation in islets and dissociated β-cells. Conventional PCR assays and immunostaining confirmed that β-cells express RyR2, the cardiac RyR isoform. Extended incubation of β-cell islets with inhibitory ryanodine suppressed GSIS; so did the antioxidant N-acetyl cysteine (NAC), which also decreased insulin secretion induced by glucose plus caffeine. Inhibitory ryanodine or NAC did not affect insulin secretion induced by glucose plus carbachol, which engages inositol 1,4,5-trisphosphate receptors. Incubation of islets with H2O2 in basal glucose increased insulin secretion 2-fold. Inhibitory ryanodine significantly decreased H2O2-stimulated insulin secretion and prevented the 4.5-fold increase of cytoplasmic [Ca2+] produced by incubation of dissociated β-cells with H2O2. Addition of stimulatory glucose or H2O2 (in basal glucose) to β-cells disaggregated from islets increased RyR2 S-glutathionylation to similar levels, measured by a proximity ligation assay; in contrast, NAC significantly reduced the RyR2 S-glutathionylation increase produced by stimulatory glucose. We propose that RyR2-mediated Ca2+ release, induced by the concomitant increases in [Ca2+] and ROS produced by stimulatory glucose, is an essential step in GSIS.
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Affiliation(s)
- Paola Llanos
- Institute for Research in Dental Sciences, Facultad de Odontología, Universidad de Chile, Santiago, Chile
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Ariel Contreras-Ferrat
- Institute for Research in Dental Sciences, Facultad de Odontología, Universidad de Chile, Santiago, Chile
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Genaro Barrientos
- Physiology and Biophysics Program, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Marco Valencia
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - David Mears
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Human Genetics Program, Institute of Biomedical Sciences, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Cecilia Hidalgo
- Center of Molecular Studies of the Cell, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Physiology and Biophysics Program, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Biomedical Neuroscience Institute, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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36
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Davis LC, Platt FM, Galione A. Preferential Coupling of the NAADP Pathway to Exocytosis in T-Cells. MESSENGER (LOS ANGELES, CALIF. : PRINT) 2015; 4:53-66. [PMID: 27330870 PMCID: PMC4910867 DOI: 10.1166/msr.2015.1040] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A cytotoxic T-lymphocyte (CTL) kills an infected or tumorigenic cell by Ca2+-dependent exocytosis of cytolytic granules at the immunological synapse formed between the two cells. However, these granules are more than reservoirs of secretory cytolytic proteins but may also serve as unique Ca2+ signaling hubs that autonomously generate their own signals for exocytosis. This review discusses a selective role for the Ca2+-mobilizing messenger, nicotinic acid adenine dinucleotide phosphate (NAADP) and its molecular targets, two-pore channels (TPCs), in stimulating exocytosis. Given that TPCs reside on the exocytotic granules themselves, these vesicles generate as well as respond to NAADP-dependent Ca2+ signals, which may have wider implications for stimulus-secretion coupling, vesicular fusion, and patho-physiology.
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Affiliation(s)
- Lianne C. Davis
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Frances M. Platt
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Antony Galione
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
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37
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Pancreatic β-cell identity, glucose sensing and the control of insulin secretion. Biochem J 2015; 466:203-18. [PMID: 25697093 DOI: 10.1042/bj20141384] [Citation(s) in RCA: 239] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Insulin release from pancreatic β-cells is required to maintain normal glucose homoeostasis in man and many other animals. Defective insulin secretion underlies all forms of diabetes mellitus, a disease currently reaching epidemic proportions worldwide. Although the destruction of β-cells is responsible for Type 1 diabetes (T1D), both lowered β-cell mass and loss of secretory function are implicated in Type 2 diabetes (T2D). Emerging results suggest that a functional deficiency, involving de-differentiation of the mature β-cell towards a more progenitor-like state, may be an important driver for impaired secretion in T2D. Conversely, at least in rodents, reprogramming of islet non-β to β-cells appears to occur spontaneously in models of T1D, and may occur in man. In the present paper, we summarize the biochemical properties which define the 'identity' of the mature β-cell as a glucose sensor par excellence. In particular, we discuss the importance of suppressing a group of 11 'disallowed' housekeeping genes, including Ldha and the monocarboxylate transporter Mct1 (Slc16a1), for normal nutrient sensing. We then survey the changes in the expression and/or activity of β-cell-enriched transcription factors, including FOXO1, PDX1, NKX6.1, MAFA and RFX6, as well as non-coding RNAs, which may contribute to β-cell de-differentiation and functional impairment in T2D. The relevance of these observations for the development of new approaches to treat T1D and T2D is considered.
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Pulli I, Blom T, Löf C, Magnusson M, Rimessi A, Pinton P, Törnquist K. A novel chimeric aequorin fused with caveolin-1 reveals a sphingosine kinase 1-regulated Ca²⁺ microdomain in the caveolar compartment. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2173-82. [PMID: 25892494 DOI: 10.1016/j.bbamcr.2015.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 03/13/2015] [Accepted: 04/07/2015] [Indexed: 11/18/2022]
Abstract
Caveolae are plasma membrane invaginations enriched in sterols and sphingolipids. Sphingosine kinase 1 (SK1) is an oncogenic protein that converts sphingosine to sphingosine 1-phosphate (S1P), which is a messenger molecule involved in calcium signaling. Caveolae contain calcium responsive proteins, but the effects of SK1 or S1P on caveolar calcium signaling have not been investigated. We generated a Caveolin-1-Aequorin fusion protein (Cav1-Aeq) that can be employed for monitoring the local calcium concentration at the caveolae ([Ca²⁺]cav). In HeLa cells, Cav1-Aeq reported different [Ca²⁺] as compared to the plasma membrane [Ca²⁺] in general (reported by SNAP25-Aeq) or as compared to the cytosolic [Ca²⁺] (reported by cyt-Aeq). The Ca²⁺ signals detected by Cav1-Aeq were significantly attenuated when the caveolar structures were disrupted by methyl-β-cyclodextrin, suggesting that the caveolae are specific targets for Ca²⁺ signaling. HeLa cells overexpressing SK1 showed increased [Ca²⁺]cav during histamine-induced Ca²⁺ mobilization in the absence of extracellular Ca²⁺ as well as during receptor-operated Ca²⁺ entry (ROCE). The SK1-induced increase in [Ca²⁺]cav during ROCE was reverted by S1P receptor antagonists. In accordance, pharmacologic inhibition of SK1 reduced the [Ca²⁺]cav during ROCE. S1P treatment stimulated the [Ca²⁺]cav upon ROCE. The Ca²⁺ responses at the plasma membrane in general were not affected by SK1 expression. In summary, our results show that SK1/S1P-signaling regulates Ca²⁺ signals at the caveolae. This article is part of a Special Issue entitled: 13th European Symposium on Calcium.
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Affiliation(s)
- Ilari Pulli
- Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland
| | - Tomas Blom
- University Of Helsinki, 00014 Helsinki, Finland
| | - Christoffer Löf
- University Of Turku, Department of Physiology, Institute of Biomedicine, Kiinamyllynkatu 10, 20520 Turku, Finland
| | | | - Alessandro Rimessi
- University of Ferrara, Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), 44121 Ferrara, Italy
| | - Paolo Pinton
- University of Ferrara, Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology, Laboratory for Technologies of Advanced Therapies (LTTA), 44121 Ferrara, Italy
| | - Kid Törnquist
- Åbo Akademi University, Tykistökatu 6A, 20520 Turku, Finland; Minerva Foundation Institute For Medical Research, Biomedicum Helsinki, 00270 Helsinki, Finland.
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Stasiuk GJ, Minuzzi F, Sae-Heng M, Rivas C, Juretschke HP, Piemonti L, Allegrini PR, Laurent D, Duckworth AR, Beeby A, Rutter GA, Long NJ. Dual-modal magnetic resonance/fluorescent zinc probes for pancreatic β-cell mass imaging. Chemistry 2015; 21:5023-33. [PMID: 25736590 PMCID: PMC4464533 DOI: 10.1002/chem.201406008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Indexed: 11/11/2022]
Abstract
Despite the contribution of changes in pancreatic β-cell mass to the development of all forms of diabetes mellitus, few robust approaches currently exist to monitor these changes prospectively in vivo. Although magnetic-resonance imaging (MRI) provides a potentially useful technique, targeting MRI-active probes to the β cell has proved challenging. Zinc ions are highly concentrated in the secretory granule, but they are relatively less abundant in the exocrine pancreas and in other tissues. We have therefore developed functional dual-modal probes based on transition-metal chelates capable of binding zinc. The first of these, Gd⋅1, binds Zn(II) directly by means of an amidoquinoline moiety (AQA), thus causing a large ratiometric Stokes shift in the fluorescence from λem =410 to 500 nm with an increase in relaxivity from r1 =4.2 up to 4.9 mM(-1) s(-1) . The probe is efficiently accumulated into secretory granules in β-cell-derived lines and isolated islets, but more poorly by non-endocrine cells, and leads to a reduction in T1 in human islets. In vivo murine studies of Gd⋅1 have shown accumulation of the probe in the pancreas with increased signal intensity over 140 minutes.
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Affiliation(s)
- Graeme J Stasiuk
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London SW7 2AZ (UK)
| | - Florencia Minuzzi
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of MedicineImperial College London, Hammersmith Hospital, London W12 0NN (UK)
| | - Myra Sae-Heng
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London SW7 2AZ (UK)
| | - Charlotte Rivas
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London SW7 2AZ (UK)
| | - Hans-Paul Juretschke
- Sanofi-Aventis Deutschland GmbH, R&D DSAR/BiomakersBiom & Biol Ass, FF, Industriepark Hoechst, Building H825, 65926 Frankfurt (Germany)
| | - Lorenzo Piemonti
- Diabetes Research Institute, IRCCS San Raffaele Scientific InstituteVia Olgettina 60, 20132 Milano (Italy)
| | | | - Didier Laurent
- Novartis Institute for Biomedical Research, Fabrikstrasse10-2.40.4, 4056, Basel (Switzerland)
| | - Andrew R Duckworth
- Department of Chemistry, Durham University, South RoadDurham, DH1 3LE (UK)
| | - Andrew Beeby
- Department of Chemistry, Durham University, South RoadDurham, DH1 3LE (UK)
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of MedicineImperial College London, Hammersmith Hospital, London W12 0NN (UK)
| | - Nicholas J Long
- Department of Chemistry, Imperial College LondonSouth Kensington Campus, London SW7 2AZ (UK)
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40
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Evolution of acidic Ca2+ stores and their resident Ca2+-permeable channels. Cell Calcium 2015; 57:222-30. [DOI: 10.1016/j.ceca.2014.12.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 12/05/2014] [Accepted: 12/09/2014] [Indexed: 11/18/2022]
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Ottolini D, Calì T, Brini M. Methods to measure intracellular Ca(2+) fluxes with organelle-targeted aequorin-based probes. Methods Enzymol 2015; 543:21-45. [PMID: 24924126 DOI: 10.1016/b978-0-12-801329-8.00002-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The photoprotein aequorin generates blue light upon binding of Ca(2+) ions. Together with its very low Ca(2+)-buffering capacity and the possibility to add specific targeting sequences, this property has rendered aequorin particularly suitable to monitor Ca(2+) concentrations in specific subcellular compartments. Recently, a new generation of genetically encoded Ca(2+) probes has been developed by fusing Ca(2+)-responsive elements with the green fluorescent protein (GFP). Aequorin has also been employed to this aim, resulting in an aequorin-GFP chimera with the Ca(2+) sensitivity of aequorin and the fluorescent properties of GFP. This setup has actually solved the major limitation of aequorin, for example, its poor ability to emit light, which rendered it inappropriate for the monitoring of Ca(2+) waves at the single-cell level by imaging. In spite of the numerous genetically encoded Ca(2+) indicators that are currently available, aequorin-based probes remain the method of election when an accurate quantification of Ca(2+) levels is required. Here, we describe currently available aequorin variants and their use for monitoring Ca(2+) waves in specific subcellular compartments. Among various applications, this method is relevant for the study of the alterations of Ca(2+) homeostasis that accompany oncogenesis, tumor progression, and response to therapy.
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Affiliation(s)
- Denis Ottolini
- Department of Biology, University of Padova, Padova, Italy
| | - Tito Calì
- Department of Biology, University of Padova, Padova, Italy
| | - Marisa Brini
- Department of Biology, University of Padova, Padova, Italy.
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42
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Morgan AJ, Davis LC, Galione A. Imaging approaches to measuring lysosomal calcium. Methods Cell Biol 2015; 126:159-95. [DOI: 10.1016/bs.mcb.2014.10.031] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Syntaxin 5-dependent retrograde transport to the trans-Golgi network is required for adeno-associated virus transduction. J Virol 2014; 89:1673-87. [PMID: 25410859 DOI: 10.1128/jvi.02520-14] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED Intracellular transport of recombinant adeno-associated virus (AAV) is still incompletely understood. In particular, the trafficking steps preceding the release of incoming AAV particles from the endosomal system into the cytoplasm, allowing subsequent nuclear import and the initiation of gene expression, remain to be elucidated fully. Others and we previously showed that a significant proportion of viral particles are transported to the Golgi apparatus and that Golgi apparatus disruption caused by the drug brefeldin A efficiently blocks AAV serotype 2 (AAV2) transduction. However, because brefeldin A is known to exert pleiotropic effects on the entire endosomal system, the functional relevance of transport to the Golgi apparatus for AAV transduction remains to be established definitively. Here, we show that AAV2 trafficking toward the trans-Golgi network (TGN) and the Golgi apparatus correlates with transduction efficiency and relies on a nonclassical retrograde transport pathway that is independent of the retromer complex, late endosomes, and recycling endosomes. AAV2 transduction is unaffected by the knockdown of syntaxins 6 and 16, which are two major effectors in the retrograde transport of both exogenous and endogenous cargo. On the other hand, inhibition of syntaxin 5 function by small interfering RNA silencing or treatment with cyclized Retro-2 strongly decreases AAV2 transduction and transport to the Golgi apparatus. This inhibition of transduction is observed with several AAV serotypes and a number of primary and immortalized cells. Together, our data strongly suggest that syntaxin 5-mediated retrograde transport to the Golgi apparatus is a broadly conserved feature of AAV trafficking that appears to be independent of the identity of the receptors used for viral attachment. IMPORTANCE Gene therapy constitutes a promising approach for the treatment of life-threatening conditions refractory to any other form of remedy. Adeno-associated virus (AAV) vectors are currently being evaluated for the treatment of diseases such as Duchenne muscular dystrophy, hemophilia, heart failure, Parkinson's disease, and others. Despite their promise as gene delivery vehicles, a better understanding of the biology of AAV-based vectors is necessary to improve further their efficacy. AAV vectors must reach the nucleus in order to deliver their genome, and their intracellular transport is not fully understood. Here, we dissect an important step of the intracellular journey of AAV by showing that retrograde transport of capsids to the trans-Golgi network is necessary for gene delivery. We show that the AAV trafficking route differs from that of known Golgi apparatus-targeted cargos, and we raise the possibility that this nonclassical pathway is shared by most AAV variants, regardless of their attachment receptors.
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44
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Gilon P, Chae HY, Rutter GA, Ravier MA. Calcium signaling in pancreatic β-cells in health and in Type 2 diabetes. Cell Calcium 2014; 56:340-61. [DOI: 10.1016/j.ceca.2014.09.001] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/26/2014] [Accepted: 09/01/2014] [Indexed: 12/24/2022]
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Yang SN, Shi Y, Yang G, Li Y, Yu J, Berggren PO. Ionic mechanisms in pancreatic β cell signaling. Cell Mol Life Sci 2014; 71:4149-77. [PMID: 25052376 PMCID: PMC11113777 DOI: 10.1007/s00018-014-1680-6] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 07/03/2014] [Accepted: 07/10/2014] [Indexed: 01/07/2023]
Abstract
The function and survival of pancreatic β cells critically rely on complex electrical signaling systems composed of a series of ionic events, namely fluxes of K(+), Na(+), Ca(2+) and Cl(-) across the β cell membranes. These electrical signaling systems not only sense events occurring in the extracellular space and intracellular milieu of pancreatic islet cells, but also control different β cell activities, most notably glucose-stimulated insulin secretion. Three major ion fluxes including K(+) efflux through ATP-sensitive K(+) (KATP) channels, the voltage-gated Ca(2+) (CaV) channel-mediated Ca(2+) influx and K(+) efflux through voltage-gated K(+) (KV) channels operate in the β cell. These ion fluxes set the resting membrane potential and the shape, rate and pattern of firing of action potentials under different metabolic conditions. The KATP channel-mediated K(+) efflux determines the resting membrane potential and keeps the excitability of the β cell at low levels. Ca(2+) influx through CaV1 channels, a major type of β cell CaV channels, causes the upstroke or depolarization phase of the action potential and regulates a wide range of β cell functions including the most elementary β cell function, insulin secretion. K(+) efflux mediated by KV2.1 delayed rectifier K(+) channels, a predominant form of β cell KV channels, brings about the downstroke or repolarization phase of the action potential, which acts as a brake for insulin secretion owing to shutting down the CaV channel-mediated Ca(2+) entry. These three ion channel-mediated ion fluxes are the most important ionic events in β cell signaling. This review concisely discusses various ionic mechanisms in β cell signaling and highlights KATP channel-, CaV1 channel- and KV2.1 channel-mediated ion fluxes.
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Affiliation(s)
- Shao-Nian Yang
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-171 76, Stockholm, Sweden,
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Pizzo P, Lissandron V, Pozzan T. The trans-Golgi compartment. Commun Integr Biol 2014; 3:462-4. [DOI: 10.4161/cib.3.5.12473] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2010] [Accepted: 05/25/2010] [Indexed: 11/19/2022] Open
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47
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Zatyka M, Da Silva Xavier G, Bellomo EA, Leadbeater W, Astuti D, Smith J, Michelangeli F, Rutter GA, Barrett TG. Sarco(endo)plasmic reticulum ATPase is a molecular partner of Wolfram syndrome 1 protein, which negatively regulates its expression. Hum Mol Genet 2014; 24:814-27. [PMID: 25274773 DOI: 10.1093/hmg/ddu499] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Wolfram syndrome is an autosomal recessive disorder characterized by neurodegeneration and diabetes mellitus. The gene responsible for the syndrome (WFS1) encodes an endoplasmic reticulum (ER)-resident transmembrane protein that is involved in the regulation of the unfolded protein response (UPR), intracellular ion homeostasis, cyclic adenosine monophosphate production and regulation of insulin biosynthesis and secretion. In this study, single cell Ca(2+) imaging with fura-2 and direct measurements of free cytosolic ATP concentration ([ATP]CYT) with adenovirally expressed luciferase confirmed a reduced and delayed rise in cytosolic free Ca(2+) concentration ([Ca(2+)]CYT), and additionally, diminished [ATP]CYT rises in response to elevated glucose concentrations in WFS1-depleted MIN6 cells. We also observed that sarco(endo)plasmic reticulum ATPase (SERCA) expression was elevated in several WFS1-depleted cell models and primary islets. We demonstrated a novel interaction between WFS1 and SERCA by co-immunoprecipitation in Cos7 cells and with endogenous proteins in human neuroblastoma cells. This interaction was reduced when cells were treated with the ER stress inducer dithiothreitol. Treatment of WFS1-depleted neuroblastoma cells with the proteasome inhibitor MG132 resulted in reduced accumulation of SERCA levels compared with wild-type cells. Together these results reveal a role for WFS1 in the negative regulation of SERCA and provide further insights into the function of WFS1 in calcium homeostasis.
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Affiliation(s)
| | - Gabriela Da Silva Xavier
- Department of Cell Biology, Division of Medicine, Faculty of Medicine, Imperial Centre for Translation and Experimental Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Elisa A Bellomo
- Department of Cell Biology, Division of Medicine, Faculty of Medicine, Imperial Centre for Translation and Experimental Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | | | - Dewi Astuti
- Department of Medical and Molecular Genetics
| | - Joel Smith
- Department of Medical and Molecular Genetics
| | - Frank Michelangeli
- School of Clinical and Experimental Medicine, The Medical School School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK and
| | - Guy A Rutter
- Department of Cell Biology, Division of Medicine, Faculty of Medicine, Imperial Centre for Translation and Experimental Medicine, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
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Leon-Pinzon C, Cercós MG, Noguez P, Trueta C, De-Miguel FF. Exocytosis of serotonin from the neuronal soma is sustained by a serotonin and calcium-dependent feedback loop. Front Cell Neurosci 2014; 8:169. [PMID: 25018697 PMCID: PMC4072984 DOI: 10.3389/fncel.2014.00169] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 06/02/2014] [Indexed: 11/25/2022] Open
Abstract
The soma of many neurons releases large amounts of transmitter molecules through an exocytosis process that continues for hundreds of seconds after the end of the triggering stimulus. Transmitters released in this way modulate the activity of neurons, glia and blood vessels over vast volumes of the nervous system. Here we studied how somatic exocytosis is maintained for such long periods in the absence of electrical stimulation and transmembrane Ca(2+) entry. Somatic exocytosis of serotonin from dense core vesicles could be triggered by a train of 10 action potentials at 20 Hz in Retzius neurons of the leech. However, the same number of action potentials produced at 1 Hz failed to evoke any exocytosis. The 20-Hz train evoked exocytosis through a sequence of intracellular Ca(2+) transients, with each transient having a different origin, timing and intracellular distribution. Upon electrical stimulation, transmembrane Ca(2+) entry through L-type channels activated Ca(2+)-induced Ca(2+) release. A resulting fast Ca(2+) transient evoked an early exocytosis of serotonin from sparse vesicles resting close to the plasma membrane. This Ca(2+) transient also triggered the transport of distant clusters of vesicles toward the plasma membrane. Upon exocytosis, the released serotonin activated autoreceptors coupled to phospholipase C, which in turn produced an intracellular Ca(2+) increase in the submembrane shell. This localized Ca(2+) increase evoked new exocytosis as the vesicles in the clusters arrived gradually at the plasma membrane. In this way, the extracellular serotonin elevated the intracellular Ca(2+) and this Ca(2+) evoked more exocytosis. The resulting positive feedback loop maintained exocytosis for the following hundreds of seconds until the last vesicles in the clusters fused. Since somatic exocytosis displays similar kinetics in neurons releasing different types of transmitters, the data presented here contributes to understand the cellular basis of paracrine neurotransmission.
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Affiliation(s)
- Carolina Leon-Pinzon
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de MéxicoMéxico D.F., México
| | - Montserrat G. Cercós
- Departamento de Neurofisiología, Instituto Nacional de Psiquiatriìa Ramoìn de la Fuente MunñizMéxico D.F., México
| | - Paula Noguez
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de MéxicoMéxico D.F., México
| | - Citlali Trueta
- Departamento de Neurofisiología, Instituto Nacional de Psiquiatriìa Ramoìn de la Fuente MunñizMéxico D.F., México
| | - Francisco F. De-Miguel
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de MéxicoMéxico D.F., México
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Wong AKC, Capitanio P, Lissandron V, Bortolozzi M, Pozzan T, Pizzo P. Heterogeneity of Ca2+ handling among and within Golgi compartments. J Mol Cell Biol 2014; 5:266-76. [PMID: 23918284 DOI: 10.1093/jmcb/mjt024] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The Golgi apparatus (GA) is a dynamic intracellular Ca(2+) store endowed with complex Ca(2+) homeostatic mechanisms in part distinct from those of the endoplasmic reticulum (ER). We describe the generation of a novel fluorescent Ca(2+) probe selectively targeted to the medial-Golgi. We demonstrate that in the medial-Golgi: (i) Ca(2+) accumulation takes advantage of two distinct pumps, the sarco/endoplasmic reticulum Ca(2+) ATPase and the secretory pathway Ca(2+) ATPase1; (ii) activation of IP3 or ryanodine receptors causes Ca(2+) release, while no functional two-pore channel was found; (iii) luminal Ca(2+) concentration appears higher than that of the trans-Golgi, but lower than that of the ER, suggesting the existence of a cis- to trans-Golgi Ca(2+) concentration gradient. Thus, the GA represents a Ca(2+) store of high complexity where, despite the continuous flow of membranes and luminal contents, each sub-compartment maintains its Ca(2+) identity with specific Ca(2+) homeostatic characteristics. The functional role of such micro-heterogeneity in GA Ca(2+) handling is discussed.
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Affiliation(s)
- Andrea K C Wong
- Department of Biomedical Sciences, University of Padua, 35121 Padua, Italy
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GAP, an aequorin-based fluorescent indicator for imaging Ca2+ in organelles. Proc Natl Acad Sci U S A 2014; 111:2584-9. [PMID: 24501126 DOI: 10.1073/pnas.1316539111] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genetically encoded calcium indicators allow monitoring subcellular Ca(2+) signals inside organelles. Most genetically encoded calcium indicators are fusions of endogenous calcium-binding proteins whose functionality in vivo may be perturbed by competition with cellular partners. We describe here a novel family of fluorescent Ca(2+) sensors based on the fusion of two Aequorea victoria proteins, GFP and apo-aequorin (GAP). GAP exhibited a unique combination of features: dual-excitation ratiometric imaging, high dynamic range, good signal-to-noise ratio, insensitivity to pH and Mg(2+), tunable Ca(2+) affinity, uncomplicated calibration, and targetability to five distinct organelles. Moreover, transgenic mice for endoplasmic reticulum-targeted GAP exhibited a robust long-term expression that correlated well with its reproducible performance in various neural tissues. This biosensor fills a gap in the actual repertoire of Ca(2+) indicators for organelles and becomes a valuable tool for in vivo Ca(2+) imaging applications.
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