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Kim S, Kang SJ, Nguyen HS, Jeong SW. Store-operated calcium entry in the satellite glial cells of rat sympathetic ganglia. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2024; 28:93-103. [PMID: 38154968 PMCID: PMC10762485 DOI: 10.4196/kjpp.2024.28.1.93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 12/15/2023] [Accepted: 12/17/2023] [Indexed: 12/30/2023]
Abstract
Satellite glial cells (SGCs), a major type of glial cell in the autonomic ganglia, closely envelop the cell body and even the synaptic regions of a single neuron with a very narrow gap. This structurally unique organization suggests that autonomic neurons and SGCs may communicate reciprocally. Glial Ca2+ signaling is critical for controlling neural activity. Here, for the first time we identified the machinery of store-operated Ca2+ entry (SOCE) which is critical for cellular Ca2+ homeostasis in rat sympathetic ganglia under normal and pathological states. Quantitative realtime PCR and immunostaining analyses showed that Orai1 and stromal interaction molecules 1 (STIM1) proteins are the primary components of SOCE machinery in the sympathetic ganglia. When the internal Ca2+ stores were depleted in the absence of extracellular Ca2+, the number of plasmalemmal Orai1 puncta was increased in neurons and SGCs, suggesting activation of the Ca2+ entry channels. Intracellular Ca2+ imaging revealed that SOCE was present in SGCs and neurons; however, the magnitude of SOCE was much larger in the SGCs than in the neurons. The SOCE was significantly suppressed by GSK7975A, a selective Orai1 blocker, and Pyr6, a SOCE blocker. Lipopolysaccharide (LPS) upregulated the glial fibrillary acidic protein and Toll-like receptor 4 in the sympathetic ganglia. Importantly, LPS attenuated SOCE via downregulating Orai1 and STIM1 expression. In conclusion, sympathetic SGCs functionally express the SOCE machinery, which is indispensable for intracellular Ca2+ signaling. The SOCE is highly susceptible to inflammation, which may affect sympathetic neuronal activity and thereby autonomic output.
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Affiliation(s)
- Sohyun Kim
- Department of Physiology, Laboratory of Molecular Neurophysiology, Yonsei University Wonju College of Medicine, Wonju 26426, Korea
| | - Seong Jun Kang
- Department of Physiology, Laboratory of Molecular Neurophysiology, Yonsei University Wonju College of Medicine, Wonju 26426, Korea
| | - Huu Son Nguyen
- Department of Physiology, Laboratory of Molecular Neurophysiology, Yonsei University Wonju College of Medicine, Wonju 26426, Korea
| | - Seong-Woo Jeong
- Department of Physiology, Laboratory of Molecular Neurophysiology, Yonsei University Wonju College of Medicine, Wonju 26426, Korea
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2
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Sampieri A, Asanov A, Méndez-Acevedo KM, Vaca L. SIDT2 Associates with Apolipoprotein A1 (ApoA1) and Facilitates ApoA1 Secretion in Hepatocytes. Cells 2023; 12:2353. [PMID: 37830567 PMCID: PMC10571540 DOI: 10.3390/cells12192353] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/08/2023] [Accepted: 09/13/2023] [Indexed: 10/14/2023] Open
Abstract
SIDT2 is a lysosomal protein involved in the degradation of nucleic acids and the transport of cholesterol between membranes. Previous studies identified two "cholesterol recognition/interaction amino acid consensus" (CRAC) motifs in SIDT1 and SIDT2 members. We have previously shown that the first CRAC motif (CRAC-1) is essential for protein translocation to the PM upon cholesterol depletion in the cell. In the present study, we show that SIDT2 and the apolipoprotein A1 (ApoA1) form a complex which requires the second CRAC-2 motif in SIDT2 to be established. The overexpression of SIDT2 and ApoA1 results in enhanced ApoA1 secretion by HepG2 cells. This is not observed when overexpressing the SIDT2 with the CRAC-2 domain mutated to render it unfunctional. All these results provide evidence of a novel role for SIDT2 as a protein forming a complex with ApoA1 and enhancing its secretion to the extracellular space.
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Affiliation(s)
- Alicia Sampieri
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City 04510, Mexico;
| | | | - Kevin Manuel Méndez-Acevedo
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome-MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK;
| | - Luis Vaca
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, México City 04510, Mexico;
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Li Y, Li N, Luan C, Pei Y, Zheng Q, Yan B, Ma X, Liu W. Identification of novel key markers that are induced during traumatic brain injury in mice. PeerJ 2023; 11:e15981. [PMID: 37645012 PMCID: PMC10461542 DOI: 10.7717/peerj.15981] [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: 05/01/2023] [Accepted: 08/08/2023] [Indexed: 08/31/2023] Open
Abstract
Background Traumatic brain injury (TBI) has emerged as an increasing public health problem but has not been well studied, particularly the mechanisms of brain cellular behaviors during TBI. Methods In this study, we established an ischemia/reperfusion (I/R) brain injury mice model using transient middle cerebral artery occlusion (tMCAO) strategy. After then, RNA-sequencing of frontal lobes was performed to screen key inducers during TBI. To further verify the selected genes, we collected peripheral blood mononuclear cells (PBMCs) from TBI patients within 24 h who attended intensive care unit (ICU) in the Affiliated Hospital of Yangzhou University and analyzed the genes expression using RT-qPCR. Finally, the receiver operator characteristic (ROC) curves and co-expression with cellular senescence markers were applied to evaluate the predictive value of the genes. Results A total of six genes were screened out from the RNA-sequencing based on their novelty in TBI and implications in apoptosis and cellular senescence signaling. RT-qPCR analysis of PBMCs from patients showed the six genes were all up-regulated during TBI after comparing with healthy volunteers who attended the hospital for physical examination. The area under ROC (AUC) curves were all >0.7, and the co-expression scores of the six genes with senescence markers were all significantly positive. We thus identified TGM1, TGM2, ATF3, RCN3, ORAI1 and ITPR3 as novel key markers that are induced during TBI, and these markers may also serve as potential predictors for the progression of TBI.
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Affiliation(s)
- Yucheng Li
- Department of Intensive Care, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu, China
| | - Ningbo Li
- Department of Intensive Care, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu, China
| | - Changjiao Luan
- Department of Intensive Care, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu, China
- Department of Lung, the Third People’s Hospital of Yangzhou, Yangzhou, China
| | - Yunlong Pei
- Department of Intensive Care, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu, China
| | - Qingbin Zheng
- Department of Intensive Care, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu, China
| | - Bingchun Yan
- Department of Neurology, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, China
| | - Xingjie Ma
- Department of Intensive Care, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu, China
| | - Weili Liu
- Department of Intensive Care, the Affiliated Hospital of Yangzhou University, Yangzhou University, Yangzhou, Jiangsu, China
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4
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Wang Q, #, Zhang Y, #, Du Q, Zhao X, Wang W, Zhai Q, Xiang M. SKF96365 impedes spinal glutamatergic transmission-mediated neuropathic allodynia. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2023; 27:39-48. [PMID: 36575932 PMCID: PMC9806642 DOI: 10.4196/kjpp.2023.27.1.39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/18/2022] [Accepted: 09/08/2022] [Indexed: 12/29/2022]
Abstract
Spinal nerve injury causes mechanical allodynia and structural imbalance of neurotransmission, which were typically associated with calcium overload. Store-operated calcium entry (SOCE) is considered crucial elements-mediating intracellular calcium homeostasis, ion channel activity, and synaptic plasticity. However, the underlying mechanism of SOCE in mediating neuronal transmitter release and synaptic transmission remains ambiguous in neuropathic pain. Neuropathic rats were operated by spinal nerve ligations. Neurotransmissions were assessed by whole-cell recording in substantia gelatinosa. Immunofluorescence staining of STIM1 with neuronal and glial biomarkers in the spinal dorsal horn. The endoplasmic reticulum stress level was estimated from qRT-PCR. Intrathecal injection of SOCE antagonist SKF96365 dose-dependently alleviated mechanical allodynia in ipsilateral hind paws of neuropathic rats with ED50 of 18 μg. Immunofluorescence staining demonstrated that STIM1 was specifically and significantly expressed in neurons but not astrocytes and microglia in the spinal dorsal horn. Bath application of SKF96365 inhibited enhanced miniature excitatory postsynaptic currents in a dosage-dependent manner without affecting miniature inhibitory postsynaptic currents. Mal-adaption of SOCE was commonly related to endoplasmic reticulum (ER) stress in the central nervous system. SKF96365 markedly suppressed ER stress levels by alleviating mRNA expression of C/EBP homologous protein and heat shock protein 70 in neuropathic rats. Our findings suggested that nerve injury might promote SOCE-mediated calcium levels, resulting in long-term imbalance of spinal synaptic transmission and behavioral sensitization, SKF96365 produces antinociception by alleviating glutamatergic transmission and ER stress. This work demonstrated the involvement of SOCE in neuropathic pain, implying that SOCE might be a potential target for pain management.
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Affiliation(s)
- Qiru Wang
- Department of Pharmacy, Fudan University Shanghai Cancer Center, Minhang Branch, Shanghai 200240, China
| | - #
- Department of Pharmacy, Fudan University Shanghai Cancer Center, Minhang Branch, Shanghai 200240, China
| | - Yang Zhang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai 200240, China
| | - #
- Department of Pharmacy, Fudan University Shanghai Cancer Center, Minhang Branch, Shanghai 200240, China
| | - Qiong Du
- Department of Pharmacy, Fudan University Shanghai Cancer Center, Minhang Branch, Shanghai 200240, China
| | - Xinjie Zhao
- Department of Pharmacy, Fudan University Shanghai Cancer Center, Minhang Branch, Shanghai 200240, China
| | - Wei Wang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai 200240, China,Correspondence Ming Xiang, E-mail: , Qing Zhai, E-mail: , Wei Wang, E-mail:
| | - Qing Zhai
- Department of Pharmacy, Fudan University Shanghai Cancer Center, Minhang Branch, Shanghai 200240, China,Correspondence Ming Xiang, E-mail: , Qing Zhai, E-mail: , Wei Wang, E-mail:
| | - Ming Xiang
- Department of Pharmacy, Fudan University Shanghai Cancer Center, Minhang Branch, Shanghai 200240, China,Correspondence Ming Xiang, E-mail: , Qing Zhai, E-mail: , Wei Wang, E-mail:
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5
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Schmaul S, Hanuscheck N, Bittner S. Astrocytic potassium and calcium channels as integrators of the inflammatory and ischemic CNS microenvironment. Biol Chem 2021; 402:1519-1530. [PMID: 34455729 DOI: 10.1515/hsz-2021-0256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 08/13/2021] [Indexed: 12/24/2022]
Abstract
Astrocytes are key regulators of their surroundings by receiving and integrating stimuli from their local microenvironment, thereby regulating glial and neuronal homeostasis. Cumulating evidence supports a plethora of heterogenic astrocyte subpopulations that differ morphologically and in their expression patterns of receptors, transporters and ion channels, as well as in their functional specialisation. Astrocytic heterogeneity is especially relevant under pathological conditions. In experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis (MS), morphologically distinct astrocytic subtypes were identified and could be linked to transcriptome changes during different disease stages and regions. To allow for continuous awareness of changing stimuli across age and diseases, astrocytes are equipped with a variety of receptors and ion channels allowing the precise perception of environmental cues. Recent studies implicate the diverse repertoire of astrocytic ion channels - including transient receptor potential channels, voltage-gated calcium channels, inwardly rectifying K+ channels, and two-pore domain potassium channels - in sensing the brain state in physiology, inflammation and ischemia. Here, we review current evidence regarding astrocytic potassium and calcium channels and their functional contribution in homeostasis, neuroinflammation and stroke.
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Affiliation(s)
- Samantha Schmaul
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn2), University Medical Centre of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, D-55131 Mainz, Germany
| | - Nicholas Hanuscheck
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn2), University Medical Centre of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, D-55131 Mainz, Germany
| | - Stefan Bittner
- Department of Neurology, Focus Program Translational Neuroscience (FTN) and Immunotherapy (FZI), Rhine Main Neuroscience Network (rmn2), University Medical Centre of the Johannes Gutenberg University Mainz, Langenbeckstraße 1, D-55131 Mainz, Germany
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Clarke D, Beros J, Bates KA, Harvey AR, Tang AD, Rodger J. Low intensity repetitive magnetic stimulation reduces expression of genes related to inflammation and calcium signalling in cultured mouse cortical astrocytes. Brain Stimul 2020; 14:183-191. [PMID: 33359601 DOI: 10.1016/j.brs.2020.12.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/26/2022] Open
Abstract
Repetitive transcranial magnetic stimulation (rTMS) is a form of non-invasive brain stimulation frequently used to induce neuroplasticity in the brain. Even at low intensities, rTMS has been shown to modulate aspects of neuronal plasticity such as motor learning and structural reorganisation of neural tissue. However, the impact of low intensity rTMS on glial cells such as astrocytes remains largely unknown. This study investigated changes in RNA (qPCR array: 125 selected genes) and protein levels (immunofluorescence) in cultured mouse astrocytes following a single session of low intensity repetitive magnetic stimulation (LI-rMS - 18 mT). Purified neonatal cortical astrocyte cultures were stimulated with either 1Hz (600 pulses), 10Hz (600 or 6000 pulses) or sham (0 pulses) LI-rMS, followed by RNA extraction at 5 h post-stimulation, or fixation at either 5 or 24-h post-stimulation. LI-rMS resulted in a two-to-four-fold downregulation of mRNA transcripts related to calcium signalling (Stim1 and Orai3), inflammatory molecules (Icam1) and neural plasticity (Ncam1). 10Hz reduced expression of Stim1, Orai3, Kcnmb4, and Ncam1 mRNA, whereas 1Hz reduced expression of Icam1 mRNA and signalling-related genes. Protein levels followed a similar pattern for 10Hz rMS, with a significant reduction of STIM1, ORAI3, KCNMB4, and NCAM1 protein compared to sham, but 1Hz increased STIM1 and ORAI3 protein levels relative to sham. These findings demonstrate the ability of 1Hz and 10Hz LI-rMS to modulate specific aspects of astrocytic phenotype, potentially contributing to the known effects of low intensity rTMS on excitability and neuroplasticity.
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Affiliation(s)
- Darren Clarke
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia.
| | - Jamie Beros
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia
| | - Kristyn A Bates
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Alan R Harvey
- Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia; School of Human Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia
| | - Alexander D Tang
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia
| | - Jennifer Rodger
- Experimental and Regenerative Neuroscience, School of Biological Sciences, The University of Western Australia, Nedlands, WA, 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA, 6009, Australia
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7
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Serwach K, Gruszczynska-Biegala J. Target Molecules of STIM Proteins in the Central Nervous System. Front Mol Neurosci 2020; 13:617422. [PMID: 33424550 PMCID: PMC7786003 DOI: 10.3389/fnmol.2020.617422] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/02/2020] [Indexed: 12/16/2022] Open
Abstract
Stromal interaction molecules (STIMs), including STIM1 and STIM2, are single-pass transmembrane proteins that are located predominantly in the endoplasmic reticulum (ER). They serve as calcium ion (Ca2+) sensors within the ER. In the central nervous system (CNS), they are involved mainly in Orai-mediated store-operated Ca2+ entry (SOCE). The key molecular components of the SOCE pathway are well-characterized, but the molecular mechanisms that underlie the regulation of this pathway need further investigation. Numerous intracellular target proteins that are located in the plasma membrane, ER, cytoskeleton, and cytoplasm have been reported to play essential roles in concert with STIMs, such as conformational changes in STIMs, their translocation, the stabilization of their interactions with Orai, and the activation of other channels. The present review focuses on numerous regulators, such as Homer, SOCE-associated regulatory factor (SARAF), septin, synaptopodin, golli proteins, partner of STIM1 (POST), and transcription factors and proteasome inhibitors that regulate STIM-Orai interactions in the CNS. Further we describe novel roles of STIMs in mediating Ca2+ influx via other than Orai pathways, including TRPC channels, VGCCs, AMPA and NMDA receptors, and group I metabotropic glutamate receptors. This review also summarizes recent findings on additional molecular targets of STIM proteins including SERCA, IP3Rs, end-binding proteins (EB), presenilin, and CaMKII. Dysregulation of the SOCE-associated toolkit, including STIMs, contributes to the development of neurodegenerative disorders (e.g., Alzheimer's disease, Parkinson's disease, and Huntington's disease), traumatic brain injury, epilepsy, and stroke. Emerging evidence points to the role of STIM proteins and several of their molecular effectors and regulators in neuronal and glial physiology and pathology, suggesting their potential application for future therapeutic strategies.
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Affiliation(s)
- Karolina Serwach
- Molecular Biology Unit, Mossakowski Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland
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8
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Zhang I, Hu H. Store-Operated Calcium Channels in Physiological and Pathological States of the Nervous System. Front Cell Neurosci 2020; 14:600758. [PMID: 33328896 PMCID: PMC7732603 DOI: 10.3389/fncel.2020.600758] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/03/2020] [Indexed: 12/13/2022] Open
Abstract
Store-operated calcium channels (SOCs) are widely expressed in excitatory and non-excitatory cells where they mediate significant store-operated calcium entry (SOCE), an important pathway for calcium signaling throughout the body. While the activity of SOCs has been well studied in non-excitable cells, attention has turned to their role in neurons and glia in recent years. In particular, the role of SOCs in the nervous system has been extensively investigated, with links to their dysregulation found in a wide variety of neurological diseases from Alzheimer’s disease (AD) to pain. In this review, we provide an overview of their molecular components, expression, and physiological role in the nervous system and describe how the dysregulation of those roles could potentially lead to various neurological disorders. Although further studies are still needed to understand how SOCs are activated under physiological conditions and how they are linked to pathological states, growing evidence indicates that SOCs are important players in neurological disorders and could be potential new targets for therapies. While the role of SOCE in the nervous system continues to be multifaceted and controversial, the study of SOCs provides a potentially fruitful avenue into better understanding the nervous system and its pathologies.
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Affiliation(s)
- Isis Zhang
- Department of Anesthesiology, Rutgers New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
| | - Huijuan Hu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States
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Ingiosi AM, Hayworth CR, Harvey DO, Singletary KG, Rempe MJ, Wisor JP, Frank MG. A Role for Astroglial Calcium in Mammalian Sleep and Sleep Regulation. Curr Biol 2020; 30:4373-4383.e7. [PMID: 32976809 PMCID: PMC7919541 DOI: 10.1016/j.cub.2020.08.052] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 07/07/2020] [Accepted: 08/13/2020] [Indexed: 10/23/2022]
Abstract
Mammalian sleep expression and regulation have historically been thought to reflect the activity of neurons. Changes in other brain cells (glia) across the sleep-wake cycle and their role in sleep regulation are comparatively unexplored. We show that sleep and wakefulness are accompanied by state-dependent changes in astroglial activity. Using a miniature microscope in freely behaving mice and a two-photon microscope in head-fixed, unanesthetized mice, we show that astroglial calcium signals are highest in wake and lowest in sleep and are most pronounced in astroglial processes. We also find that astroglial calcium signals during non-rapid eye movement sleep change in proportion to sleep need. In contrast to neurons, astrocytes become less synchronized during non-rapid eye movement sleep after sleep deprivation at the network and single-cell level. Finally, we show that conditionally reducing intracellular calcium in astrocytes impairs the homeostatic response to sleep deprivation. Thus, astroglial calcium activity changes dynamically across vigilance states, is proportional to sleep need, and is a component of the sleep homeostat.
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Affiliation(s)
- Ashley M Ingiosi
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, East Spokane Falls Boulevard, Spokane, WA 99202, USA
| | - Christopher R Hayworth
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, East Spokane Falls Boulevard, Spokane, WA 99202, USA
| | - Daniel O Harvey
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, East Spokane Falls Boulevard, Spokane, WA 99202, USA
| | - Kristan G Singletary
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, East Spokane Falls Boulevard, Spokane, WA 99202, USA
| | - Michael J Rempe
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, East Spokane Falls Boulevard, Spokane, WA 99202, USA; Department of Mathematics and Computer Science, Whitworth University, West Hawthorne Road, Spokane, WA 99251, USA
| | - Jonathan P Wisor
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, East Spokane Falls Boulevard, Spokane, WA 99202, USA
| | - Marcos G Frank
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University, East Spokane Falls Boulevard, Spokane, WA 99202, USA.
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Verkhratsky A, Parpura V, Vardjan N, Zorec R. Physiology of Astroglia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1175:45-91. [PMID: 31583584 DOI: 10.1007/978-981-13-9913-8_3] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Astrocytes are principal cells responsible for maintaining the brain homeostasis. Additionally, these glial cells are also involved in homocellular (astrocyte-astrocyte) and heterocellular (astrocyte-other cell types) signalling and metabolism. These astroglial functions require an expression of the assortment of molecules, be that transporters or pumps, to maintain ion concentration gradients across the plasmalemma and the membrane of the endoplasmic reticulum. Astrocytes sense and balance their neurochemical environment via variety of transmitter receptors and transporters. As they are electrically non-excitable, astrocytes display intracellular calcium and sodium fluctuations, which are not only used for operative signalling but can also affect metabolism. In this chapter we discuss the molecules that achieve ionic gradients and underlie astrocyte signalling.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, M13 9PT, UK. .,Faculty of Health and Medical Sciences, Center for Basic and Translational Neuroscience, University of Copenhagen, 2200, Copenhagen, Denmark. .,Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011, Bilbao, Spain.
| | - Vladimir Parpura
- Department of Neurobiology, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Nina Vardjan
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia.,Celica Biomedical, Ljubljana, Slovenia
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KCa3.1 deficiency attenuates neuroinflammation by regulating an astrocyte phenotype switch involving the PI3K/AKT/GSK3β pathway. Neurobiol Dis 2019; 132:104588. [PMID: 31470105 DOI: 10.1016/j.nbd.2019.104588] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 07/22/2019] [Accepted: 08/23/2019] [Indexed: 12/26/2022] Open
Abstract
Neuroinflammation may induce a phenotype switch to reactive astrogliosis in neurodegenerative disorders. The calcium-activated potassium channel (KCa3.1) is active in the phenotypic switch that occurs during astrogliosis in Alzheimer's disease and ischemic stroke. Here, transcriptome sequencing (RNA-Seq), immunohistochemistry, western blotting, pharmacological blockade, and calcium imaging were used to investigate astrocyte KCa3.1 activity in neuroinflammation, Tau accumulation, and insulin signaling deficits in male wild-type C57BL/6 and KCa3.1-/- knockout (KO) mice, and in primary astrocyte cultures. KCa3.1 deficiency in KO mice decreased lipopolysaccharide (LPS)-induced memory deficits, neuronal loss, glial activation, Tau phosphorylation, and insulin signaling deficits in vivo. KCa3.1 expression in astrocytes was associated with LPS-induced upregulation of the Orai1 store-operated Ca2+ channel protein. The KCa3.1 channel was found to regulate store-operated Ca2+ overload through an interaction with Orai1 in LPS-induced reactive astrocytes. The LPS-induced effects on KCa3.1 and Orai1 indirectly promoted astrogliosis-related changes via the PI3K/AKT/GSK3β and NF-κB signaling pathways in vitro. Unbiased evaluation of RNA-Seq results for actively translated RNAs confirmed that substantial astrocyte diversity was associated with KCa3.1 deficiency. Our results suggest that KCa3.1 regulated astrogliosis-mediated neuroinflammation, Tau accumulation, and insulin signaling deficiency via PI3K/AKT/GSK3β and NF-κB signaling pathways, and contributing to neuronal loss and memory deficits in this neuroinflammation mouse model.
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12
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Toth AB, Hori K, Novakovic MM, Bernstein NG, Lambot L, Prakriya M. CRAC channels regulate astrocyte Ca 2+ signaling and gliotransmitter release to modulate hippocampal GABAergic transmission. Sci Signal 2019; 12:12/582/eaaw5450. [PMID: 31113852 DOI: 10.1126/scisignal.aaw5450] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Astrocytes are the major glial subtype in the brain and mediate numerous functions ranging from metabolic support to gliotransmitter release through signaling mechanisms controlled by Ca2+ Despite intense interest, the Ca2+ influx pathways in astrocytes remain obscure, hindering mechanistic insights into how Ca2+ signaling is coupled to downstream astrocyte-mediated effector functions. Here, we identified store-operated Ca2+ release-activated Ca2+ (CRAC) channels encoded by Orai1 and STIM1 as a major route of Ca2+ entry for driving sustained and oscillatory Ca2+ signals in astrocytes after stimulation of metabotropic purinergic and protease-activated receptors. Using synaptopHluorin as an optical reporter, we showed that the opening of astrocyte CRAC channels stimulated vesicular exocytosis to mediate the release of gliotransmitters, including ATP. Furthermore, slice electrophysiological recordings showed that activation of astrocytes by protease-activated receptors stimulated interneurons in the CA1 hippocampus to increase inhibitory postsynaptic currents on CA1 pyramidal cells. These results reveal a central role for CRAC channels as regulators of astrocyte Ca2+ signaling, gliotransmitter release, and astrocyte-mediated tonic inhibition of CA1 pyramidal neurons.
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Affiliation(s)
- Anna B Toth
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Kotaro Hori
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Michaela M Novakovic
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Natalie G Bernstein
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Laurie Lambot
- Department of Physiology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Murali Prakriya
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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Heterologous calcium-dependent inactivation of Orai1 by neighboring TRPV1 channels modulates cell migration and wound healing. Commun Biol 2019; 2:88. [PMID: 30854480 PMCID: PMC6399350 DOI: 10.1038/s42003-019-0338-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 02/05/2019] [Indexed: 02/06/2023] Open
Abstract
Store-operated calcium entry (SOCE) is an essential calcium influx mechanism in animal cells. One of the most important auto regulatory control systems involves calcium-dependent inactivation (CDI) of the Orai channel, which prevents excessive calcium influx. In the present study we analyze the role of two channels in the induction of CDI on Orai1. Here we show that calcium entering through freely diffusing TRPV1 channels induce strong CDI on Orai1 while calcium entering through P2X4 channel does not. TRPV1 can induce CDI on Orai1 because both channels were found in close proximity in the cell membrane. This was not observed with P2X4 channels. To our knowledge, this is the first study demonstrating that calcium arising from different channels may contribute to the modulation of Orai1 through CDI in freely diffusing single channels of living cells. Our results highlight the role of TRPV1-mediated CDI on Orai1 in cell migration and wound healing. Bastián-Eugenio et al. showed that calcium entering the cell via TRPV1, but not P2X4 channels, can induce calcium-dependent inactivation of Orai1. This inactivation impacts thrombin-induced cell migration and wound healing suggesting an important role of Orai1 modulation by TRPV1 channels.
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Sampieri A, Santoyo K, Asanov A, Vaca L. Association of the IP3R to STIM1 provides a reduced intraluminal calcium microenvironment, resulting in enhanced store-operated calcium entry. Sci Rep 2018; 8:13252. [PMID: 30185837 PMCID: PMC6125598 DOI: 10.1038/s41598-018-31621-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 05/15/2018] [Indexed: 11/21/2022] Open
Abstract
The involvement of inositol trisphosphate receptor (IP3R) in modulating store-operated calcium entry (SOCE) was established many years ago. Nevertheless, the molecular mechanism responsible for this observation has not been elucidated to this date. In the present study we show that IP3R associates to STIM1 upon depletion of the endoplasmic reticulum (ER) by activation of the inositol trisphosphate signaling cascade via G-protein coupled receptors. IP3R-STIM1 association results in enhanced STIM1 puncta formation and larger Orai-mediated whole-cell currents as well as increased calcium influx. Depleting the ER with a calcium ATPase inhibitor (thapsigargin, TG) does not induce IP3R-STIM1 association, indicating that this association requires an active IP3R. The IP3R-STIM1 association is only observed after IP3R activation, as evidenced by FRET experiments and co-immunoprecipitation assays. ER intraluminal calcium measurements using Mag-Fluo-4 showed enhanced calcium depletion when IP3R is overexpressed. A STIM1-GCaMP fusion protein indicates that STIM1 detects lower calcium concentrations near its EF-hand domain when IP3R is overexpressed when compared with the fluorescence reported by a GCaMP homogenously distributed in the ER lumen (ER-GCaMP). All these data together strongly suggest that activation of inositol trisphosphate signaling cascade induces the formation of the IP3R-STIM1 complex. The activated IP3R provides a reduced intraluminal calcium microenvironment near STIM1, resulting in enhanced activation of Orai currents and SOCE.
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Affiliation(s)
- Alicia Sampieri
- Departamento de Biologia Celular y del Desarrollo, Instituto de Fisiología Celular. Universidad Nacional Autonoma de México, Ciudad de México, Mexico
| | - Karla Santoyo
- Departamento de Biologia Celular y del Desarrollo, Instituto de Fisiología Celular. Universidad Nacional Autonoma de México, Ciudad de México, Mexico
| | | | - Luis Vaca
- Departamento de Biologia Celular y del Desarrollo, Instituto de Fisiología Celular. Universidad Nacional Autonoma de México, Ciudad de México, Mexico.
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15
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Mei Y, Barrett JE, Hu H. Calcium release-activated calcium channels and pain. Cell Calcium 2018; 74:180-185. [PMID: 30096536 DOI: 10.1016/j.ceca.2018.07.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/10/2018] [Accepted: 07/27/2018] [Indexed: 12/30/2022]
Abstract
Calcium release-activated calcium (CRAC) channels are unique among ion channels that are activated in response to depletion of intracellular calcium stores and are highly permeable to Ca2+ compared to other cations. CRAC channels mediate an important calcium signal for a wide variety of cell types and are well studied in the immune system. They have been implicated in a number of disorders such as immunodeficiency, musculosketal disorders and cancer. There is growing evidence showing that CRAC channels are expressed in the nervous system and are involved in pathological conditions including pain. This review summarizes the expression, distribution, and function of the CRAC channel family in the dorsal root ganglion, spinal cord and some brain regions, and discusses their functional significance in neurons and glial cells and involvement in nociception and chronic pain. Although further studies are needed to understand how these channels are activated under physiological conditions, the recent findings indicate that the CRAC channel Orai1 is an important player in pain modulation and could represent a new target for pathological pain.
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Affiliation(s)
- Yixiao Mei
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, United States
| | - James E Barrett
- Department of Neurology, Drexel University College of Medicine Philadelphia, PA 19102, United States
| | - Huijuan Hu
- Department of Anesthesiology, Rutgers New Jersey Medical School, Newark, NJ 07103, United States.
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Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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17
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Verkhratsky A, Nedergaard M. Physiology of Astroglia. Physiol Rev 2018; 98:239-389. [PMID: 29351512 PMCID: PMC6050349 DOI: 10.1152/physrev.00042.2016] [Citation(s) in RCA: 895] [Impact Index Per Article: 149.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/22/2017] [Accepted: 04/27/2017] [Indexed: 02/07/2023] Open
Abstract
Astrocytes are neural cells of ectodermal, neuroepithelial origin that provide for homeostasis and defense of the central nervous system (CNS). Astrocytes are highly heterogeneous in morphological appearance; they express a multitude of receptors, channels, and membrane transporters. This complement underlies their remarkable adaptive plasticity that defines the functional maintenance of the CNS in development and aging. Astrocytes are tightly integrated into neural networks and act within the context of neural tissue; astrocytes control homeostasis of the CNS at all levels of organization from molecular to the whole organ.
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Affiliation(s)
- Alexei Verkhratsky
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
| | - Maiken Nedergaard
- The University of Manchester , Manchester , United Kingdom ; Achúcarro Basque Center for Neuroscience, IKERBASQUE, Basque Foundation for Science , Bilbao , Spain ; Department of Neuroscience, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain ; Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark ; and Center for Translational Neuromedicine, University of Rochester Medical Center , Rochester, New York
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18
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Sakuragi S, Niwa F, Oda Y, Mikoshiba K, Bannai H. Astroglial Ca 2+ signaling is generated by the coordination of IP 3R and store-operated Ca 2+ channels. Biochem Biophys Res Commun 2017; 486:879-885. [PMID: 28336440 DOI: 10.1016/j.bbrc.2017.03.096] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 03/19/2017] [Indexed: 12/21/2022]
Abstract
Astrocytes play key roles in the central nervous system and regulate local blood flow and synaptic transmission via intracellular calcium (Ca2+) signaling. Astrocytic Ca2+ signals are generated by multiple pathways: Ca2+ release from the endoplasmic reticulum (ER) via the inositol 1, 4, 5-trisphosphate receptor (IP3R) and Ca2+ influx through various Ca2+ channels on the plasma membrane. However, the Ca2+ channels involved in astrocytic Ca2+ homeostasis or signaling have not been fully characterized. Here, we demonstrate that spontaneous astrocytic Ca2+ transients in cultured hippocampal astrocytes were induced by cooperation between the Ca2+ release from the ER and the Ca2+ influx through store-operated calcium channels (SOCCs) on the plasma membrane. Ca2+ imaging with plasma membrane targeted GCaMP6f revealed that spontaneous astroglial Ca2+ transients were impaired by pharmacological blockade of not only Ca2+ release through IP3Rs, but also Ca2+ influx through SOCCs. Loss of SOCC activity resulted in the depletion of ER Ca2+, suggesting that SOCCs are activated without store depletion in hippocampal astrocytes. Our findings indicate that sustained SOCC activity, together with that of the sarco-endoplasmic reticulum Ca2+-ATPase, contribute to the maintenance of astrocytic Ca2+ store levels, ultimately enabling astrocytic Ca2+ signaling.
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Affiliation(s)
- Shigeo Sakuragi
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan
| | - Fumihiro Niwa
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute (BSI), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yoichi Oda
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan
| | - Katsuhiko Mikoshiba
- Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute (BSI), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| | - Hiroko Bannai
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan; Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute (BSI), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Nagoya Research Center for Brain & Neural Circuits, Nagoya University, Furo-cho, Chikusa, Nagoya, Aichi, 464-8602, Japan; Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan.
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19
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Papanikolaou M, Lewis A, Butt AM. Store-operated calcium entry is essential for glial calcium signalling in CNS white matter. Brain Struct Funct 2017; 222:2993-3005. [PMID: 28247021 PMCID: PMC5585307 DOI: 10.1007/s00429-017-1380-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 01/27/2017] [Indexed: 11/06/2022]
Abstract
‘Calcium signalling’ is the ubiquitous response of glial cells to multiple extracellular stimuli. The primary mechanism of glial calcium signalling is by release of calcium from intracellular stores of the endoplasmic reticulum (ER). Replenishment of ER Ca2+ stores relies on store-operated calcium entry (SOCE). However, despite the importance of calcium signalling in glial cells, little is known about their mechanisms of SOCE. Here, we investigated SOCE in glia of the mouse optic nerve, a typical CNS white matter tract that comprises bundles of myelinated axons and the oligodendrocytes and astrocytes that support them. Using quantitative RT-PCR, we identified Orai1 channels, both Stim1 and Stim2, and the transient receptor potential M3 channel (TRPM3) as the primary channels for SOCE in the optic nerve, and their expression in both astrocytes and oligodendrocytes was demonstrated by immunolabelling of optic nerve sections and cultures. The functional importance of SOCE was demonstrated by fluo-4 calcium imaging on isolated intact optic nerves and optic nerve cultures. Removal of extracellular calcium ([Ca2+]o) resulted in a marked depletion of glial cytosolic calcium ([Ca2+]i), which recovered rapidly on restoration of [Ca2+]o via SOCE. 2-aminoethoxydiphenylborane (2APB) significantly decreased SOCE and severely attenuated ATP-mediated calcium signalling. The results provide evidence that Orai/Stim and TRPM3 are important components of the ‘calcium toolkit’ that underpins SOCE and the sustainability of calcium signalling in white matter glia.
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Affiliation(s)
- M Papanikolaou
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, PO1 2DT, UK
| | - A Lewis
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, PO1 2DT, UK
| | - A M Butt
- Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Science, University of Portsmouth, Portsmouth, PO1 2DT, UK.
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Kwon J, An H, Sa M, Won J, Shin JI, Lee CJ. Orai1 and Orai3 in Combination with Stim1 Mediate the Majority of Store-operated Calcium Entry in Astrocytes. Exp Neurobiol 2017; 26:42-54. [PMID: 28243166 PMCID: PMC5326714 DOI: 10.5607/en.2017.26.1.42] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 01/31/2017] [Accepted: 01/31/2017] [Indexed: 01/06/2023] Open
Abstract
Astrocytes are non-excitable cells in the brain and their activity largely depends on the intracellular calcium (Ca2+) level. Therefore, maintaining the intracellular Ca2+ homeostasis is critical for proper functioning of astrocytes. One of the key regulatory mechanisms of Ca2+ homeostasis in astrocytes is the store-operated Ca2+ entry (SOCE). This process is mediated by a combination of the Ca2+-store-depletion-sensor, Stim, and the store-operated Ca2+-channels, Orai and TrpC families. Despite the existence of all those families in astrocytes, previous studies have provided conflicting results on the molecular identification of astrocytic SOCE. Here, using the shRNA-based gene-silencing approach and Ca2+-imaging from cultured mouse astrocytes, we report that Stim1 in combination with Orai1 and Orai3 contribute to the major portion of astrocytic SOCE. Gene-silencing of Stim1 showed a 79.2% reduction of SOCE, indicating that Stim1 is the major Ca2+-store-depletion-sensor. Further gene-silencing showed that Orai1, Orai2, Orai3, and TrpC1 contribute to SOCE by 35.7%, 20.3%, 26.8% and 12.2%, respectively. Simultaneous gene-silencing of all three Orai subtypes exhibited a 67.6% reduction of SOCE. Based on the detailed population analysis, we predict that Orai1 and Orai3 are expressed in astrocytes with a large SOCE, whereas TrpC1 is exclusively expressed in astrocytes with a small SOCE. This analytical approach allows us to identify the store operated channel (SOC) subtype in each cell by the degree of SOCE. Our results propose that Stim1 in combination with Orai1 and Orai3 are the major molecular components of astrocytic SOCE under various physiological and pathological conditions.
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Affiliation(s)
- Jea Kwon
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea.; Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Heeyoung An
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea.; Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Moonsun Sa
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea.; Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - Joungha Won
- Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Department of Biological Science, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea
| | - Jeong Im Shin
- Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
| | - C Justin Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul 02841, Korea.; Center for Neuroscience and Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea.; Center for Glia-Neuron Interaction, Korea Institute of Science and Technology (KIST), Seoul 02792, Korea
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Store-Operated Calcium Entry in Müller Glia Is Controlled by Synergistic Activation of TRPC and Orai Channels. J Neurosci 2016; 36:3184-98. [PMID: 26985029 DOI: 10.1523/jneurosci.4069-15.2016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
UNLABELLED The endoplasmic reticulum (ER) is at the epicenter of astrocyte Ca(2+) signaling. We sought to identify the molecular mechanism underlying store-operated calcium entry that replenishes ER stores in mouse Müller cells. Store depletion, induced through blockade of sequestration transporters in Ca(2+)-free saline, induced synergistic activation of canonical transient receptor potential 1 (TRPC1) and Orai channels. Store-operated TRPC1 channels were identified by their electrophysiological properties, pharmacological blockers, and ablation of the Trpc1 gene. Ca(2+) release-activated currents (ICRAC) were identified by ion permeability, voltage dependence, and sensitivity to selective Orai antagonists Synta66 and GSK7975A. Depletion-evoked calcium influx was initiated at the Müller end-foot and apical process, triggering centrifugal propagation of Ca(2+) waves into the cell body. EM analysis of the end-foot compartment showed high-density ER cisternae that shadow retinal ganglion cell (RGC) somata and axons, protoplasmic astrocytes, vascular endothelial cells, and ER-mitochondrial contacts at the vitreal surface of the end-foot. The mouse retina expresses transcripts encoding both Stim and all known Orai genes; Müller glia predominantly express stromal interacting molecule 1 (STIM1), whereas STIM2 is mainly confined to the outer plexiform and RGC layers. Elimination of TRPC1 facilitated Müller gliosis induced by the elevation of intraocular pressure, suggesting that TRPC channels might play a neuroprotective role during mechanical stress. By characterizing the properties of store-operated signaling pathways in Müller cells, these studies expand the current knowledge about the functional roles these cells play in retinal physiology and pathology while also providing further evidence for the complexity of calcium signaling mechanisms in CNS astroglia. SIGNIFICANCE STATEMENT Store-operated Ca(2+) signaling represents a major signaling pathway and source of cytosolic Ca(2+) in astrocytes. Here, we show that the store-operated response in Müller cells, radial glia that perform key structural, signaling, osmoregulatory, and mechanosensory functions within the retina, is mediated through synergistic activation of transient receptor potential and Orai channels. The end-foot disproportionately expresses the depletion sensor stromal interacting molecule 1, which contains an extraordinarily high density of endoplasmic reticulum cisternae that shadow neuronal, astrocytic, vascular, and axonal structures; interface with mitochondria; but also originate store-operated Ca(2+) entry-induced transcellular Ca(2+) waves that propagate glial excitation into the proximal retina. These results identify a molecular mechanism that underlies complex interactions between the plasma membrane and calcium stores, and contributes to astroglial function, regulation, and response to mechanical stress.
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Gao X, Xia J, Munoz FM, Manners MT, Pan R, Meucci O, Dai Y, Hu H. STIMs and Orai1 regulate cytokine production in spinal astrocytes. J Neuroinflammation 2016; 13:126. [PMID: 27245842 PMCID: PMC4886427 DOI: 10.1186/s12974-016-0594-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/23/2016] [Indexed: 12/30/2022] Open
Abstract
Background Our previous study demonstrated that a store-operated calcium channel (SOCC) inhibitor (YM-58483) has central analgesic effects. However, the cellular and molecular mechanisms of such effects remain to be determined. It is well-known that glial cells play important roles in central sensitization. SOC entry (SOCE) has been implicated in many cell types including cortical astrocytes. However, the role of the SOCC family in the function of astrocytes has not been determined. Here, we thoroughly investigated the expression and the functional significance of SOCCs in spinal astrocytes. Methods Primary cultured astrocytes were prepared from neonatal (P2–P3) CD1 mice. Expressions of mRNAs and proteins were respectively assessed by real-time PCR and Western blot analysis. SOCE was measured using a calcium imaging system. Live-cell STIM1 translocation was detected using a confocal microscope. Cytokine levels were measured by the enzyme-linked immunosorbent assay. Results We found that the SOCC family is expressed in spinal astrocytes and that depletion of calcium stores from the endoplasmic reticulum by cyclopiazonic acid (CPA) resulted in a large sustained calcium entry, which was blocked by SOCC inhibitors. Using the siRNA knockdown approach, we identified STIM1 and Orai1 as primary components of SOCCs in spinal astrocytes. We also observed thapsigargin (TG)- or CPA-induced puncta formation of STIM1 and Orai1. In addition, activation of SOCCs remarkably promoted TNF-α and IL-6 production in spinal astrocytes, which were greatly attenuated by knockdown of STIM1 or Orai1. Importantly, knockdown of STIM2 and Orai1 dramatically decreased lipopolysaccharide-induced TNF-α and IL-6 production without changing cell viability. Conclusions This study presents the first evidence that STIM1, STIM2, and Orai1 mediate SOCE and are involved in cytokine production in spinal astrocytes. Our findings provide the basis for future assessment of SOCCs in pain and other central nervous system disorders associated with abnormal astrocyte activities.
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Affiliation(s)
- Xinghua Gao
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.,Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, China
| | - Jingsheng Xia
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Frances M Munoz
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Melissa T Manners
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Rong Pan
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Olimpia Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Yue Dai
- Department of Pharmacology of Chinese Materia Medica, China Pharmaceutical University, Nanjing, China
| | - Huijuan Hu
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.
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Abstract
Stromal interaction molecules (STIM) 1 and 2 are sensors of the calcium concentration in the endoplasmic reticulum. Depletion of endoplasmic reticulum calcium stores activates STIM proteins which, in turn, bind and open calcium channels in the plasma membrane formed by the proteins ORAI1, ORAI2, and ORAI3. The resulting store-operated calcium entry (SOCE), mostly controlled by the principal components STIM1 and ORAI1, has been particularly characterized in immune cells. In the nervous system, all STIM and ORAI homologs are expressed. This review summarizes current knowledge on distribution and function of STIM and ORAI proteins in central neurons and glial cells, i.e. astrocytes and microglia. STIM2 is required for SOCE in hippocampal synapses and cortical neurons, whereas STIM1 controls calcium store replenishment in cerebellar Purkinje neurons. In microglia, STIM1, STIM2, and ORAI1 regulate migration and phagocytosis. The isoforms ORAI2 and ORAI3 are candidates for SOCE channels in neurons and astrocytes, respectively. Due to the role of SOCE in neuronal and glial calcium homeostasis, dysfunction of STIM and ORAI proteins may have consequences for the development of neurodegenerative disorders, such as Alzheimer's disease.
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Affiliation(s)
- Robert Kraft
- a Carl-Ludwig-Institute for Physiology, University of Leipzig ; Leipzig , Germany
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24
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GABAρ subunits confer a bicuculline-insensitive component to GFAP+ cells of cerebellum. Proc Natl Acad Sci U S A 2014; 111:17522-7. [PMID: 25422464 DOI: 10.1073/pnas.1419632111] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
GABA-A receptors mediating synaptic or extrasynaptic transmission are molecularly and functionally distinct, and glial cells are known to express a plethora of GABA-A subunits. Here we demonstrate that GFAP(+) cells of the granular layer of cerebellum express GABAρ subunits during early postnatal development, thereby conferring peculiar pharmacologic characteristics to GABA responses. Electron microscopy revealed the presence of GABAρ in the plasma membrane of GFAP(+) cells. In contrast, expression in the adult was restricted to Purkinje neurons and a subset of ependymal cells. Electrophysiological studies in vitro revealed that astrocytes express functional receptors with an EC50 of 52.2 ± 11.8 μM for GABA. The evoked currents were inhibited by bicuculline (100 μM) and TPMPA (IC50, 5.9 ± 0.6 μM), indicating the presence of a GABAρ component. Coimmunoprecipitation demonstrated protein-protein interactions between GABAρ1 and GABAα1, and double immunofluorescence showed that these subunits colocalize in the plasma membrane. Three populations of GABA-A receptors in astrocytes were identified: classic GABA-A, bicuculline-insensitive GABAρ, and GABA-A-GABAρ hybrids. Clusters of GABA-A receptors were distributed in the perinuclear space and along the processes of GFAP(+) cells. Time-lapse microscopy showed GABAρ2-GFP accumulation in clusters located in the soma and along the processes. The clusters were relatively immobile, with mean displacement of 9.4 ± 0.9 μm and a net distance traveled of 1-2 μm, owing mainly to directional movement or simple diffusion. Modulation of GABAρ dynamics may be a novel mechanism of extrasynaptic transmission regulating GABAergic control of GFAP(+) cells during early postnatal development.
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Misceo D, Holmgren A, Louch WE, Holme PA, Mizobuchi M, Morales RJ, De Paula AM, Stray-Pedersen A, Lyle R, Dalhus B, Christensen G, Stormorken H, Tjønnfjord GE, Frengen E. A dominant STIM1 mutation causes Stormorken syndrome. Hum Mutat 2014; 35:556-64. [PMID: 24619930 DOI: 10.1002/humu.22544] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 03/04/2014] [Indexed: 12/11/2022]
Abstract
Stormorken syndrome is a rare autosomal-dominant disease with mild bleeding tendency, thrombocytopathy, thrombocytopenia, mild anemia, asplenia, tubular aggregate myopathy, miosis, headache, and ichthyosis. A heterozygous missense mutation in STIM1 exon 7 (c.910C>T; p.Arg304Trp) (NM_003156.3) was found to segregate with the disease in six Stormorken syndrome patients in four families. Upon sensing Ca(2+) depletion in the endoplasmic reticulum lumen, STIM1 undergoes a conformational change enabling it to interact with and open ORAI1, a Ca(2+) release-activated Ca(2+) channel located in the plasma membrane. The STIM1 mutation found in Stormorken syndrome patients is located in the coiled-coil 1 domain, which might play a role in keeping STIM1 inactive. In agreement with a possible gain-of-function mutation in STIM1, blood platelets from patients were in a preactivated state with high exposure of aminophospholipids on the outer surface of the plasma membrane. Resting Ca(2+) levels were elevated in platelets from the patients compared with controls, and store-operated Ca(2+) entry was markedly attenuated, further supporting constitutive activity of STIM1 and ORAI1. Thus, our data are compatible with a near-maximal activation of STIM1 in Stormorken syndrome patients. We conclude that the heterozygous mutation c.910C>T causes the complex phenotype that defines this syndrome.
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Affiliation(s)
- Doriana Misceo
- Department of Medical Genetics, University of Oslo and Oslo University Hospital, Oslo, Norway
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Role of STIM1 in survival and neural differentiation of mouse embryonic stem cells independent of Orai1-mediated Ca2+ entry. Stem Cell Res 2014; 12:452-66. [DOI: 10.1016/j.scr.2013.12.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Revised: 12/10/2013] [Accepted: 12/17/2013] [Indexed: 11/18/2022] Open
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Müller MS, Fox R, Schousboe A, Waagepetersen HS, Bak LK. Astrocyte glycogenolysis is triggered by store-operated calcium entry and provides metabolic energy for cellular calcium homeostasis. Glia 2014; 62:526-34. [PMID: 24464850 DOI: 10.1002/glia.22623] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 12/11/2013] [Accepted: 12/16/2013] [Indexed: 01/14/2023]
Abstract
Astrocytic glycogen, the only storage form of glucose in the brain, has been shown to play a fundamental role in supporting learning and memory, an effect achieved by providing metabolic support for neurons. We have examined the interplay between glycogenolysis and the bioenergetics of astrocytic Ca(2+) homeostasis, by analyzing interdependency of glycogen and store-operated Ca(2+) entry (SOCE), a mechanism in cellular signaling that maintains high endoplasmatic reticulum (ER) Ca(2+) concentration and thus provides the basis for store-dependent Ca(2+) signaling. We stimulated SOCE in primary cultures of murine cerebellar and cortical astrocytes, and determined glycogen content to investigate the effects of SOCE on glycogen metabolism. By blocking glycogenolysis, we tested energetic dependency of SOCE-related Ca(2+) dynamics on glycogenolytic ATP. Our results show that SOCE triggers astrocytic glycogenolysis. Upon inhibition of adenylate cyclase with 2',5'-dideoxyadenosine, glycogen content was no longer significantly different from that in unstimulated control cells, indicating that SOCE triggers astrocytic glycogenolysis in a cAMP-dependent manner. When glycogenolysis was inhibited in cortical astrocytes by 1,4-dideoxy-1,4-imino-D-arabinitol, the amount of Ca(2+) loaded into ER via sarco/endoplasmic reticulum Ca(2)-ATPase (SERCA) was reduced, which suggests that SERCA pumps preferentially metabolize glycogenolytic ATP. Our study demonstrates SOCE as a novel pathway in stimulating astrocytic glycogenolysis. We also provide first evidence for a new functional role of brain glycogen, in providing local ATP to SERCA, thus establishing the bioenergetic basis for astrocytic Ca(2+) signaling. This mechanism could offer a novel explanation for the impact of glycogen on learning and memory.
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Affiliation(s)
- Margit S Müller
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark
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Luz-Madrigal A, Asanov A, Camacho-Zarco AR, Sampieri A, Vaca L. A cholesterol recognition amino acid consensus domain in GP64 fusion protein facilitates anchoring of baculovirus to mammalian cells. J Virol 2013; 87:11894-907. [PMID: 23986592 PMCID: PMC3807332 DOI: 10.1128/jvi.01356-13] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 08/22/2013] [Indexed: 02/07/2023] Open
Abstract
Baculoviridae is a large family of double-stranded DNA viruses that selectively infect insects. Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is the best-studied baculovirus from the family. Many studies over the last several years have shown that AcMNPV can enter a wide variety of mammalian cells and deliver genetic material for foreign gene expression. While most animal viruses studied so far have developed sophisticated mechanisms to selectively infect specific cells and tissues in an organism, AcMNPV can penetrate and deliver foreign genes into most cells studied to this date. The details about the mechanisms of internalization have been partially described. In the present study, we have identified a cholesterol recognition amino acid consensus (CRAC) domain present in the AcMNPV envelope fusion protein GP64. We demonstrated the association of a CRAC domain with cholesterol, which is important to facilitate the anchoring of the virus at the mammalian cell membrane. Furthermore, this initial anchoring favors AcMNPV endocytosis via a dynamin- and clathrin-dependent mechanism. Under these conditions, efficient baculovirus-driven gene expression is obtained. In contrast, when cholesterol is reduced from the plasma membrane, AcMNPV enters the cell via a dynamin- and clathrin-independent mechanism. The result of using this alternative internalization pathway is a reduced level of baculovirus-driven gene expression. This study is the first to document the importance of a novel CRAC domain in GP64 and its role in modulating gene delivery in AcMNPV.
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Affiliation(s)
- Agustin Luz-Madrigal
- Department of Biology and Center for Tissue Regeneration and Engineering, University of Dayton, Dayton, Ohio, USA
- Department of Zoology, Miami University, Oxford, Ohio, USA
| | | | - Aldo R. Camacho-Zarco
- Max Planck Institute for Biophysical Chemistry, Protein Structure Determination, Göttingen, Germany
| | - Alicia Sampieri
- Instituto de Fisiologia Celular, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Distrito Federal, Mexico
| | - Luis Vaca
- Instituto de Fisiologia Celular, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Distrito Federal, Mexico
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Li D, Agulhon C, Schmidt E, Oheim M, Ropert N. New tools for investigating astrocyte-to-neuron communication. Front Cell Neurosci 2013; 7:193. [PMID: 24194698 PMCID: PMC3810613 DOI: 10.3389/fncel.2013.00193] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 10/07/2013] [Indexed: 12/24/2022] Open
Abstract
Gray matter protoplasmic astrocytes extend very thin processes and establish close contacts with synapses. It has been suggested that the release of neuroactive gliotransmitters at the tripartite synapse contributes to information processing. However, the concept of calcium (Ca2+)-dependent gliotransmitter release from astrocytes, and the release mechanisms are being debated. Studying astrocytes in their natural environment is challenging because: (i) astrocytes are electrically silent; (ii) astrocytes and neurons express an overlapping repertoire of transmembrane receptors; (iii) the size of astrocyte processes in contact with synapses are below the resolution of confocal and two-photon microscopes (iv) bulk-loading techniques using fluorescent Ca2+ indicators lack cellular specificity. In this review, we will discuss some limitations of conventional methodologies and highlight the interest of novel tools and approaches for studying gliotransmission. Genetically encoded Ca2+ indicators (GECIs), light-gated channels, and exogenous receptors are being developed to selectively read out and stimulate astrocyte activity. Our review discusses emerging perspectives on: (i) the complexity of astrocyte Ca2+ signaling revealed by GECIs; (ii) new pharmacogenetic and optogenetic approaches to activate specific Ca2+ signaling pathways in astrocytes; (iii) classical and new techniques to monitor vesicle fusion in cultured astrocytes; (iv) possible strategies to express specifically reporter genes in astrocytes.
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Affiliation(s)
- Dongdong Li
- Biophysics of Gliotransmitter Release Team, Laboratory of Neurophysiology and New Microscopies, INSERM U603, CNRS UMR 8154, University Paris Descartes Paris, France
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Li JH, Zhao ST, Wu CY, Cao X, Peng MR, Li SJ, Liu XA, Gao TM. Store-Operated Ca2+ Channels Blockers Inhibit Lipopolysaccharide Induced Astrocyte Activation. Neurochem Res 2013; 38:2216-26. [DOI: 10.1007/s11064-013-1130-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Revised: 07/13/2013] [Accepted: 08/08/2013] [Indexed: 02/08/2023]
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A relay mechanism between EB1 and APC facilitate STIM1 puncta assembly at endoplasmic reticulum-plasma membrane junctions. Cell Calcium 2013; 54:246-56. [PMID: 23871111 DOI: 10.1016/j.ceca.2013.06.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 06/19/2013] [Accepted: 06/21/2013] [Indexed: 12/20/2022]
Abstract
The assembly of STIM1 protein puncta near endoplasmic reticulum-plasma membrane (ER-PM) junctions is required for optimal activation of store-operated channels (SOC). The mechanisms controlling the translocation of STIM1 puncta to ER-PM junctions remain largely unknown. In the present study, we have explored the role of the microtubule binding protein adenomatous polyposis coli (APC), on STIM1 puncta and store-operated calcium entry (SOCE). APC-depleted cells showed reduced STIM1 puncta near ER-PM junctions, instead puncta is found at the ER surrounding the cell nucleus. Reduced STIM1 puncta near ER-PM junctions in APC-depleted cells correlates with a strong inhibition of SOCE and diminished Orai whole-cell currents. Immunoprecipitation and confocal microscopy co-localization studies indicate that, upon depletion of the ER, STIM1 dissociates from EB1 and associates to APC. Deletion analysis identified an APC-binding domain in the carboxyl terminus of STIM1 (STIM1 650-685). These results together position APC as an important element in facilitating the translocation of STIM1 puncta near ER-PM junctions, which in turn is required for efficient SOCE and Orai activation upon depletion of the ER.
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Verkhratsky A, Parpura V. Store-operated calcium entry in neuroglia. Neurosci Bull 2013; 30:125-33. [PMID: 23677809 DOI: 10.1007/s12264-013-1343-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2013] [Accepted: 02/14/2013] [Indexed: 11/30/2022] Open
Abstract
Neuroglial cells are homeostatic neural cells. Generally, they are electrically non-excitable and their activation is associated with the generation of complex intracellular Ca(2+) signals that define the "Ca(2+) excitability" of glia. In mammalian glial cells the major source of Ca(2+) for this excitability is the lumen of the endoplasmic reticulum (ER), which is ultimately (re)filled from the extracellular space. This occurs via store-operated Ca(2+) entry (SOCE) which is supported by a specific signaling system connecting the ER with plasmalemmal Ca(2+) entry. Here, emptying of the ER Ca(2+) store is necessary and sufficient for the activation of SOCE, and without Ca(2+) influx via SOCE the ER store cannot be refilled. The molecular arrangements underlying SOCE are relatively complex and include plasmalemmal channels, ER Ca(2+) sensors, such as stromal interaction molecule, and possibly ER Ca(2+) pumps (of the SERCA type). There are at least two sets of plasmalemmal channels mediating SOCE, the Ca(2+)-release activated channels, Orai, and transient receptor potential (TRP) channels. The molecular identity of neuroglial SOCE has not been yet identified unequivocally. However, it seems that Orai is predominantly expressed in microglia, whereas astrocytes and oligodendrocytes rely more on TRP channels to produce SOCE. In physiological conditions the SOCE pathway is instrumental for the sustained phase of the Ca(2+) signal observed following stimulation of metabotropic receptors on glial cells.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, M13 9PT, UK,
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Milošević M, Stenovec M, Kreft M, Petrušić V, Stević Z, Trkov S, Andjus PR, Zorec R. Immunoglobulins G from patients with sporadic amyotrophic lateral sclerosis affects cytosolic Ca2+ homeostasis in cultured rat astrocytes. Cell Calcium 2013; 54:17-25. [PMID: 23623373 DOI: 10.1016/j.ceca.2013.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 03/28/2013] [Accepted: 03/30/2013] [Indexed: 12/23/2022]
Abstract
Astrocytes are considered essential in the etiopathogenesis of amyotrophic lateral sclerosis (ALS). We have demonstrated previously that immunoglobulins G (IgG) isolated from patients with ALS enhance the mobility of acidic vesicles in cultured astrocytes in a Ca(2+)-dependent manner. Here we directly examined the impact of purified sporadic ALS IgG on cytosolic [Ca(2+)] ([Ca(2+)]i) in astrocytes. Confocal time-lapse images were acquired and fluorescence of a non-ratiometric Ca(2+) indicator was recorded before and after the application of IgG. ALS IgG (0.1 mg/ml) from 7 patients evoked transient increases in [Ca(2+)]i in ~50% of tested astrocytes. The probability of observing a response was independent of extracellular Ca(2+). The peak increase in [Ca(2+)]i developed ~3 times faster and the time integral of evoked transients was ~2-fold larger; the peak amplitude itself was not affected by extracellular Ca(2+). Application of pharmacological inhibitors revealed that activation of inositol-1,4,5-triphosphate receptors is necessary and sufficient to initiate transients in [Ca(2+)]i; the Ca(2+) influx through store-operated calcium entry prolongs the transient increase in [Ca(2+)]i. Thus, ALS IgG acutely affect [Ca(2+)]i by mobilizing both, intra- and extracellular Ca(2+) into the cytosol of cultured astrocytes.
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Affiliation(s)
- Milena Milošević
- University of Ljubljana, Medical Faculty, Institute of Pathophysiology, Laboratory of Neuroendocrinology-Molecular Cell Physiology, Zaloška cesta 4, 1000 Ljubljana, Slovenia
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Verkhratsky A, Reyes RC, Parpura V. TRP channels coordinate ion signalling in astroglia. Rev Physiol Biochem Pharmacol 2013; 166:1-22. [PMID: 23784619 DOI: 10.1007/112_2013_15] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Astroglial excitability is based on highly spatio-temporally coordinated fluctuations of intracellular ion concentrations, among which changes in Ca(2+) and Na(+) take the leading role. Intracellular signals mediated by Ca(2+) and Na(+) target numerous molecular cascades that control gene expression, energy production and numerous homeostatic functions of astrocytes. Initiation of Ca(2+) and Na(+) signals relies upon plasmalemmal and intracellular channels that allow fluxes of respective ions down their concentration gradients. Astrocytes express several types of TRP channels of which TRPA1 channels are linked to regulation of functional expression of GABA transporters, whereas TRPV4 channels are activated following osmotic challenges and are up-regulated in ischaemic conditions. Astrocytes also ubiquitously express several isoforms of TRPC channels of which heteromers assembled from TRPC1, 4 and/or 5 subunits that likely act as stretch-activated channels and are linked to store-operated Ca(2+) entry. The TRPC channels mediate large Na(+) fluxes that are associated with the endoplasmic reticulum Ca(2+) signalling machinery and hence coordinate Na(+) and Ca(2+) signalling in astroglia.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK,
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Abstract
The name astroglia unifies many non-excitable neural cells that act as primary homeostatic cells in the nervous system. Neuronal activity triggers multiple homeostatic responses of astroglia that include increase in metabolic activity and synthesis of neuronal preferred energy substrate lactate, clearance of neurotransmitters and buffering of extracellular K(+) ions to name but a few. Many (if not all) of astroglial homeostatic responses are controlled by dynamic changes in the cytoplasmic concentration of two cations, Ca(2+) and Na(+). Intracellular concentration of these ions is tightly controlled by several transporters and can be rapidly affected by the activation of respective fluxes through ionic channels or ion exchangers. Here, we provide a comprehensive review of astroglial Ca(2+) and Na(+) signalling.
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