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Napier M, Reynolds K, Scott AL. Glial-mediated dysregulation of neurodevelopment in Fragile X Syndrome. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 173:187-215. [PMID: 37993178 DOI: 10.1016/bs.irn.2023.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2023]
Abstract
Astrocytes are highly involved in a multitude of developmental processes that are known to be dysregulated in Fragile X Syndrome. Here, we examine these processes individually and review the roles astrocytes play in contributing to the pathology of this syndrome. As a growing area of interest in the field, new and exciting insight is continually emerging. Understanding these glial-mediated roles is imperative for elucidating the underlying molecular mechanisms at play, not only in Fragile X Syndrome, but also other ASD-related disorders. Understanding these roles will be central to the future development of effective, clinically-relevant treatments of these disorders.
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Affiliation(s)
- M Napier
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada; Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada
| | - K Reynolds
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada; Department of Neuroscience, Tufts University School of Medicine, Boston, United States
| | - A L Scott
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Canada; Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Canada.
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2
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Kim D, Chen D, Ahsan N, Jorge GL, Thelen JJ, Stacey G. The Raf-like MAPKKK INTEGRIN-LINKED KINASE 5 regulates purinergic receptor-mediated innate immunity in Arabidopsis. THE PLANT CELL 2023; 35:1572-1592. [PMID: 36762404 PMCID: PMC10118279 DOI: 10.1093/plcell/koad029] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 01/31/2023] [Indexed: 06/17/2023]
Abstract
Mitogen-activated protein (MAP) kinase signaling cascades play important roles in eukaryotic defense against various pathogens. Activation of the extracellular ATP (eATP) receptor P2K1 triggers MAP kinase 3 and 6 (MPK3/6) phosphorylation, which leads to an elevated plant defense response. However, the mechanism by which P2K1 activates the MAPK cascade is unclear. In this study, we show that in Arabidopsis thaliana, P2K1 phosphorylates the Raf-like MAP kinase kinase kinase (MAPKKK) INTEGRIN-LINKED KINASE 5 (ILK5) on serine 192 in the presence of eATP. The interaction between P2K1 and ILK5 was confirmed both in vitro and in planta and their interaction was enhanced by ATP treatment. Similar to P2K1 expression, ILK5 expression levels were highly induced by treatment with ATP, flg22, Pseudomonas syringae pv. tomato DC3000, and various abiotic stresses. ILK5 interacts with and phosphorylates the MAP kinase MKK5. Moreover, phosphorylation of MPK3/6 was significantly reduced upon ATP treatment in ilk5 mutant plants, relative to wild-type (WT). The ilk5 mutant plants showed higher susceptibility to P. syringae pathogen infection relative to WT plants. Plants expressing only the mutant ILK5S192A protein, with decreased kinase activity, did not activate the MAPK cascade upon ATP addition. These results suggest that eATP activation of P2K1 results in transphosphorylation of the Raf-like MAPKKK ILK5, which subsequently triggers the MAPK cascade, culminating in activation of MPK3/6 associated with an elevated innate immune response.
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Affiliation(s)
- Daewon Kim
- Division of Plant Science and Technology, C.S. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
| | - Dongqin Chen
- Division of Plant Science and Technology, C.S. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
| | - Nagib Ahsan
- Division of Biochemistry, C.S. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
| | - Gabriel Lemes Jorge
- Division of Biochemistry, C.S. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
| | - Jay J Thelen
- Division of Biochemistry, C.S. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
| | - Gary Stacey
- Division of Plant Science and Technology, C.S. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
- Division of Biochemistry, C.S. Bond Life Science Center, University of Missouri, Columbia, MO 65211, USA
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Lohr C. Role of P2Y receptors in astrocyte physiology and pathophysiology. Neuropharmacology 2023; 223:109311. [PMID: 36328064 DOI: 10.1016/j.neuropharm.2022.109311] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 10/24/2022] [Accepted: 10/27/2022] [Indexed: 11/07/2022]
Abstract
Astrocytes are active constituents of the brain that manage ion homeostasis and metabolic support of neurons and directly tune synaptic transmission and plasticity. Astrocytes express all known P2Y receptors. These regulate a multitude of physiological functions such as cell proliferation, Ca2+ signalling, gliotransmitter release and neurovascular coupling. In addition, P2Y receptors are fundamental in the transition of astrocytes into reactive astrocytes, as occurring in many brain disorders such as neurodegenerative diseases, neuroinflammation and epilepsy. This review summarizes the current literature addressing the function of P2Y receptors in astrocytes in the healthy brain as well as in brain diseases.
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Affiliation(s)
- Christian Lohr
- Institute of Cell and Systems Biology of Animals, University of Hamburg, Germany.
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4
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Shakir Alkhafaji R, Muhsin Khalfa H, LF Almsaid H. Rat Hepatocellular Primary Cells: A Cellular and Genetic Assessment of the Chitosan Nanoparticles-Induced Damage and Cytotoxicity. ARCHIVES OF RAZI INSTITUTE 2022; 77:579-584. [PMID: 36284954 PMCID: PMC9548247 DOI: 10.22092/ari.2022.357103.1974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/16/2022] [Indexed: 01/25/2023]
Abstract
Chitosan (CH) is a non-toxic vital polymer that is derived naturally from chitin. Due to its anti-bacterial and anti-fungal properties, it has attracted researchers' attention. The anti-bacterial activity of 1-3 CH is ideal in an acidic medium due to its weak solubility at pH levels higher than 6.5. The type of CH and the degree of its polymerization affect its anti-microbial activity, as well as some of its other chemical and physical properties. The present study was conducted to investigate the damage induced by chitosan nanoparticles (CHNPs) at various concentrations on the cultured rat hepatic cells. The CHNPs were synthesized by the ionotropic gelation of CH with sodium tripolyphosphate anions. Hepatic cells were cultured from tissues freshly isolated from the liver of normal laboratory rats. Cells were allowed to reach a confluence level before the treatment with CHNPs. In total, five different concentrations of CHNPs were used, and cell cytotoxicity was evaluated using the MTT assay. The genetic expression of P2Y1, P2Y2, and P2Y4 purinergic receptors was evaluated on the cellular level using Qualitative Reverse Transcription Polymerase Chain Reaction technique. The primary culture of rat hepatic cells was thoroughly exposed to a range of CHNPs. Under normal conditions, the cells showed normal cellular morphology with clearly defined borders and normal nuclear structure. Apoptotic cellular damage was observed in the cultured hepatic cells when exposed to CHNPs. Moreover, irregular cellular morphology and heavy pigmentation were noticed in the hepatic cells when exposed to a high concentration of CHNPs. Purinergic receptor gene expression indicated an inflammatory response by an increased gene fold change post-exposure to CHNPs. This study concludes that CHNPs have a strong cytotoxic effect on the cultured rat hepatic cells. Overall, CHNPs showed an inhibitory response to hepatic cells evoking a purine receptor-mediated inflammatory response.
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Affiliation(s)
- R Shakir Alkhafaji
- Department of Biology, Faculty of Sciences, University of Kufa, Kufa, Iraq
| | - H Muhsin Khalfa
- Department of Biology, Faculty of Sciences, University of Kufa, Kufa, Iraq
| | - H LF Almsaid
- Department of Biology, Faculty of Sciences, University of Kufa, Kufa, Iraq
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Donati V, Peres C, Nardin C, Scavizzi F, Raspa M, Ciubotaru CD, Bortolozzi M, Pedersen MG, Mammano F. Calcium Signaling in the Photodamaged Skin: In Vivo Experiments and Mathematical Modeling. FUNCTION 2021; 3:zqab064. [PMID: 35330924 PMCID: PMC8788836 DOI: 10.1093/function/zqab064] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Revised: 11/23/2021] [Accepted: 11/23/2021] [Indexed: 01/07/2023] Open
Abstract
The epidermis forms an essential barrier against a variety of insults. The overall goal of this study was to shed light not only on the effects of accidental epidermal injury, but also on the mechanisms that support laser skin resurfacing with intra-epidermal focal laser-induced photodamage, a widespread medical practice used to treat a range of skin conditions. To this end, we selectively photodamaged a single keratinocyte with intense, focused and pulsed laser radiation, triggering Ca2+ waves in the epidermis of live anesthetized mice with ubiquitous expression of a genetically encoded Ca2+ indicator. Waves expanded radially and rapidly, reaching up to eight orders of bystander cells that remained activated for tens of minutes, without displaying oscillations of the cytosolic free Ca2+ concentration ([Formula: see text]). By combining in vivo pharmacological dissection with mathematical modeling, we demonstrate that Ca2+ wave propagation depended primarily on the release of ATP, a prime damage-associated molecular patterns (DAMPs), from the hit cell. Increments of the [Formula: see text] in bystander cells were chiefly due to Ca2+ release from the endoplasmic reticulum (ER), downstream of ATP binding to P2Y purinoceptors. ATP-dependent ATP release though connexin hemichannels (HCs) affected wave propagation at larger distances, where the extracellular ATP concentration was reduced by the combined effect of passive diffusion and hydrolysis due to the action of ectonucleotidases, whereas pannexin channels had no role. Bifurcation analysis suggests basal keratinocytes have too few P2Y receptors (P2YRs) and/or phospholipase C (PLC) to transduce elevated extracellular ATP levels into inositol trisphosphate (IP3) production rates sufficiently large to sustain [Formula: see text] oscillations.
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Affiliation(s)
- Viola Donati
- Department of Physics and Astronomy “G. Galilei”, University of Padova, 35131 Padova, Italy
- Institute of Biochemistry and Cell Biology (IBBC)-CNR, 00015 Monterotondo (RM), Italy
| | - Chiara Peres
- Institute of Biochemistry and Cell Biology (IBBC)-CNR, 00015 Monterotondo (RM), Italy
| | - Chiara Nardin
- Institute of Biochemistry and Cell Biology (IBBC)-CNR, 00015 Monterotondo (RM), Italy
| | - Ferdinando Scavizzi
- Institute of Biochemistry and Cell Biology (IBBC)-CNR, 00015 Monterotondo (RM), Italy
| | - Marcello Raspa
- Institute of Biochemistry and Cell Biology (IBBC)-CNR, 00015 Monterotondo (RM), Italy
| | | | - Mario Bortolozzi
- Department of Physics and Astronomy “G. Galilei”, University of Padova, 35131 Padova, Italy
- Institute of Biochemistry and Cell Biology (IBBC)-CNR, 00015 Monterotondo (RM), Italy
- Foundation for Advanced Biomedical Research, Veneto Institute of Molecular Medicine (VIMM), 35129 Padova (PD), Italy
| | - Morten Gram Pedersen
- Department of Information Engineering, University of Padova, 35131 Padova (PD), Italy
- Department of Mathematics “Tullio Levi-Civita”, University of Padova, 35121 Padova (PD), Italy
| | - Fabio Mammano
- Department of Physics and Astronomy “G. Galilei”, University of Padova, 35131 Padova, Italy
- Institute of Biochemistry and Cell Biology (IBBC)-CNR, 00015 Monterotondo (RM), Italy
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Sun CC, Lee SY, Kao CH, Chen LH, Shen ZQ, Lai CH, Tzeng TY, Pang JHS, Chiu WT, Tsai TF. Cisd2 plays an essential role in corneal epithelial regeneration. EBioMedicine 2021; 73:103654. [PMID: 34740104 PMCID: PMC8577409 DOI: 10.1016/j.ebiom.2021.103654] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/24/2021] [Accepted: 10/14/2021] [Indexed: 02/05/2023] Open
Abstract
Background Age-related changes affecting the ocular surface cause vision loss in the elderly. Cisd2 deficiency drives premature aging in mice as well as resulting in various ocular surface abnormalities. Here we investigate the role of CISD2 in corneal health and disease. Methods We studied the molecular mechanism underlying the ocular phenotypes brought about by Cisd2 deficiency using both Cisd2 knockout (KO) mice and a human corneal epithelial cell (HCEC) cell line carrying a CRISPR-mediated CISD2KO background. We also develop a potential therapeutic strategy that targets the Ca2+ signaling pathway, which has been found to be dysregulated in the corneal epithelium of subjects with ocular surface disease in order to extend the mechanistic findings into a translational application. Findings Firstly, in patients with corneal epithelial disease, CISD2 is down-regulated in their corneal epithelial cells. Secondly, using mouse cornea, Cisd2 deficiency causes a cycle of chronic injury and persistent repair resulting in exhaustion of the limbal progenitor cells. Thirdly, in human corneal epithelial cells, CISD2 deficiency disrupts intracellular Ca2+ homeostasis, impairing mitochondrial function, thereby retarding corneal repair. Fourthly, cyclosporine A and EDTA facilitate corneal epithelial wound healing in Cisd2 knockout mice. Finally, cyclosporine A treatment restores corneal epithelial erosion in patients with dry eye disease, which affects the ocular surface. Interpretation These findings reveal that Cisd2 plays an essential role in the cornea and that Ca2+ signaling pathways are potential targets for developing therapeutics of corneal epithelial diseases. Funding This study was supported by the Ministry of Science and Technology (MOST) and Chang Gung Medical Research Foundation, Taiwan.
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Affiliation(s)
- Chi-Chin Sun
- Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung, Taiwan; School of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shao-Yun Lee
- Department of Ophthalmology, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Cheng-Heng Kao
- Center of General Education, Chang Gung University, Taoyuan, Taiwan
| | - Li-Hsien Chen
- Department of Pharmacology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Taiwan
| | - Zhao-Qing Shen
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Chia-Hui Lai
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, Kwei-shan, Taoyuan, Taiwan
| | - Tsai-Yu Tzeng
- Cancer Progression Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Jong-Hwei Su Pang
- Graduate Institute of Clinical Medical Sciences, Chang Gung University, Kwei-shan, Taoyuan, Taiwan
| | - Wen-Tai Chiu
- Department of Biomedical Engineering, College of Engineering, National Cheng Kung University, Tainan, Taiwan.
| | - Ting-Fen Tsai
- Department of Life Sciences and Institute of Genome Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan; Aging and Health Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan; Institute of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Taiwan; Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Zhunan, Taiwan.
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7
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Al-Shorbagy MY, Wadie W, El-Tanbouly DM. Trimetazidine Modulates Mitochondrial Redox Status and Disrupted Glutamate Homeostasis in a Rat Model of Epilepsy. Front Pharmacol 2021; 12:735165. [PMID: 34690772 PMCID: PMC8531497 DOI: 10.3389/fphar.2021.735165] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/31/2021] [Indexed: 01/25/2023] Open
Abstract
Mitochondrial oxidative status exerts an important role in modulating glia–neuron interplay during epileptogenesis. Trimetazidine (TMZ), a well-known anti-ischemic drug, has shown promising potential against a wide range of neurodegenerative disorders including epilepsy. Nevertheless, the exact mechanistic rationale behind its anti-seizure potential has not been fully elucidated yet. Herein, the impact of TMZ against mitochondrial oxidative damage as well as glutamate homeostasis disruption in the hippocampus has been investigated in rats with lithium/pilocarpine (Li/PIL) seizures. Animals received 3 mEq/kg i.p. LiCl3 followed by PIL (single i.p.; 150 mg/kg) 20 h later for induction of seizures with or without TMZ pretreatment (25 mg/kg; i.p.) for five consecutive days. Seizure score and seizure latency were observed. Mitochondrial redox status as well as ATP and uncoupling protein 2 was recorded. Moreover, glutamate homeostasis was unveiled. The present findings demonstrate the TMZ-attenuated Li/PIL seizure score and latency. It improved mitochondrial redox status, preserved energy production mechanisms, and decreased reactive astrocytes evidenced as decreased glial fibrillary acidic protein immune-stained areas in hippocampal tissue. In addition, it modulated phosphorylated extracellular signal-regulated kinases (p-ERK1/2) and p-AMP–activated protein kinase (p-AMPK) signaling pathways to reflect a verified anti-apoptotic effect. Consequently, it upregulated mRNA expression of astroglial glutamate transporters and reduced the elevated glutamate level. The current study demonstrates that TMZ exhibits robust anti-seizure and neuroprotective potentials. These effects are associated with its ability to modulate mitochondrial redox status, boost p-ERK1/2 and p-AMPK signaling pathways, and restore glutamate homeostasis in hippocampus.
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Affiliation(s)
- Muhammad Y Al-Shorbagy
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.,Department of Pharmaceutical Sciences, College of Pharmacy, Gulf Medical University, Ajman, United Arab Emirates
| | - Walaa Wadie
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Dalia M El-Tanbouly
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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Grimmer B, Krauszman A, Hu X, Kabir G, Connelly KA, Li M, Grune J, Madry C, Isakson BE, Kuebler WM. Pannexin 1-a novel regulator of acute hypoxic pulmonary vasoconstriction. Cardiovasc Res 2021; 118:2535-2547. [PMID: 34668529 DOI: 10.1093/cvr/cvab326] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 09/08/2021] [Indexed: 12/16/2022] Open
Abstract
AIMS Hypoxic pulmonary vasoconstriction (HPV) is a physiological response to alveolar hypoxia that diverts blood flow from poorly ventilated to better aerated lung areas to optimize ventilation-perfusion matching. Yet, the exact sensory and signaling mechanisms by which hypoxia triggers pulmonary vasoconstriction remain incompletely understood. Recently, ATP release via pannexin 1 (Panx1) and subsequent signaling via purinergic P2Y receptors has been identified as regulator of vasoconstriction in systemic arterioles. Here, we probed for the role of Panx1-mediated ATP release in HPV and chronic hypoxic pulmonary hypertension (PH). METHODS AND RESULTS Pharmacological inhibition of Panx1 by probenecid, spironolactone, the Panx1 specific inhibitory peptide (10Panx1) and genetic deletion of Panx1 specifically in smooth muscle attenuated HPV in isolated perfused mouse lungs. In pulmonary artery smooth muscle cells (PASMC), both spironolactone and 10Panx1 attenuated the increase in intracellular Ca2+ concentration ([Ca2+]i) in response to hypoxia. Yet, genetic deletion of Panx1 in either endothelial or smooth muscle cells did not prevent the development of PH in mice. Unexpectedly, ATP release in response to hypoxia was not detectable in PASMC, and inhibition of purinergic receptors or ATP degradation by ATPase failed to attenuate HPV. Rather, transient receptor potential vanilloid 4 (TRPV4) antagonism and Panx1 inhibition inhibited the hypoxia-induced [Ca2+]i increase in PASMC in an additive manner, suggesting that Panx1 regulates [Ca2+]i independently of the ATP-P2Y-TRPV4 pathway. In line with this notion, Panx1 overexpression increased the [Ca2+]i response to hypoxia in HeLa cells. CONCLUSION In the present study we identify Panx1 as novel regulator of HPV. Yet, the role of Panx1 in HPV was not attributable to ATP release and downstream signaling via P2Y receptors or TRPV4 activation, but relates to a role of Panx1 as direct or indirect modulator of the PASMC Ca2+ response to hypoxia. Panx1 did not affect the development of chronic hypoxic PH. TRANSLATIONAL PERSPECTIVE Hypoxic pulmonary vasoconstriction (HPV) optimizes lung ventilation-perfusion matching, but also contributes to pulmonary pathologies including high altitude pulmonary edema (HAPE) or chronic hypoxic pulmonary hypertension. Here, we demonstrate that pharmaceutical inhibition as well as genetic deletion of the hemichannel pannexin-1 (Panx1) in pulmonary artery smooth muscle cells attenuates the physiological HPV response. Panx1 deficiency did, however, not prevent the development of chronic hypoxic pulmonary hypertension in mice. Panx1 inhibitors such as the mineralocorticoid receptor antagonist spironolactone may thus present a putative strategy for the prevention or treatment of HAPE, yet not for chronic hypoxic lung disease.
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Affiliation(s)
- Benjamin Grimmer
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany.,German Center for Cardiovascular Research (DZHK)
| | - Adrienn Krauszman
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany.,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Xudong Hu
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Golam Kabir
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Kim A Connelly
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada
| | - Mei Li
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Jana Grune
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Christian Madry
- Institute of Neurophysiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia, USA.,Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité-Universitätsmedizin Berlin, corporate member of the Freie Universität Berlin and Humboldt Universität zu Berlin, Berlin, Germany.,German Center for Cardiovascular Research (DZHK).,Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, ON, Canada.,Departments of Physiology and Surgery, University of Toronto, ON, Canada
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Guo X, Li Q, Pi S, Xia Y, Mao L. G protein-coupled purinergic P2Y receptor oligomerization: Pharmacological changes and dynamic regulation. Biochem Pharmacol 2021; 192:114689. [PMID: 34274353 DOI: 10.1016/j.bcp.2021.114689] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 12/12/2022]
Abstract
P2Y receptors (P2YRs) are a δ group of rhodopsin-like G protein-coupled receptors (GPCRs) with many essential functions in physiology and pathology, such as platelet aggregation, immune responses, neuroprotective effects, inflammation, and cellular proliferation. Thus, they are among the most researched therapeutic targets used for the clinical treatment of diseases (e.g., the antithrombotic drug clopidogrel and the dry eye treatment drug diquafosol). GPCRs transmit signals as dimers to increase the diversity of signalling pathways and pharmacological activities. Many studies have frequently confirmed dimerization between P2YRs and other GPCRs due to their functions in cardiovascular and cerebrovascular processes in vivo and in vitro. Recently, some P2YR dimers that dynamically balance physiological functions in the body were shown to be involved in effective signal transduction and exert pathological responses. In this review, we summarize the types, pharmacological changes, and active regulators of P2YR-related dimerization, and delineate new functions and pharmacological activities of P2YR-related dimers, which may be a novel direction to improve the effectiveness of medications.
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Affiliation(s)
- Xiaoqing Guo
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Qin Li
- Department of Vascular Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Shulan Pi
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Yuanpeng Xia
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
| | - Ling Mao
- Department of Neurology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
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10
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Juneja DS, Nasuto S, Delivopoulos E. Deriving Functional Astrocytes from Mouse Embryonic Stem Cells with a Fast and Efficient Protocol. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:2994-2996. [PMID: 31946518 DOI: 10.1109/embc.2019.8857058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A growing number of studies highlight the structural and functional diversity of astrocytes throughout the central nervous system. These cells are now seen as heterogeneous as neurons and are implicated in a number of neurological and psychiatric diseases. Efficient generation of diverse subtypes of astrocytes can be a useful tool in investigating synaptogenesis and patterns of activity in developing neural networks. In this study, we developed a protocol for the fast and efficient differentiation of astrocytes from mouse embryonic stem cells, as evidenced by the upregulation of genes related to astrocytic development (Gfap, Aldh1l1). Generated astrocytes exhibit phenotypic diversity, which is demonstrated by the variant expression of markers such as GFAP, ALDH1L1, AQP4 and S100β, amongst subgroups within the same cell population. In addition, astrocytes exhibited differential calcium transients upon stimulation with ATP. Our protocol will facilitate investigations, regarding the involvement of astrocytes in the structural and functional connectivity of neural networks.
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11
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Electroacupuncture Inhibits the Activity of Astrocytes in Spinal Cord in Rats with Visceral Hypersensitivity by Inhibiting P2Y 1 Receptor-Mediated MAPK/ERK Signaling Pathway. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2020; 2020:4956179. [PMID: 32184891 PMCID: PMC7061128 DOI: 10.1155/2020/4956179] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 11/13/2019] [Accepted: 12/27/2019] [Indexed: 02/07/2023]
Abstract
Background Irritable bowel syndrome (IBS) is a chronic functional bowel disease characterized by abdominal pain and changes in bowel habits in the absence of organic disease. Electroacupuncture (EA) has been shown to alleviate visceral hypersensitivity (VH) in IBS rat models by inhibiting the activation of astrocytes in the spinal cord. However, the underlying molecular mechanisms mediated by P2Y1 receptor of this effect of electroacupuncture remain unclear. Aim To explore whether EA inhibits the activity of astrocytes in the spinal cord dorsal horn of rat with visceral hypersensitivity by inhibiting P2Y1 receptor and its downstream mitogen activated protein kinase/extracellular regulated kinase 1 (MAPK/ERK) pathway. Methods Ten-day-old Sprague-Dawley (SD) male rats were given an intracolonic injection of 0.2 ml of 0.5% acetic acid (AA) to establish a visceral hypersensitivity model. EA was performed at Zusanli (ST 36) and Shangjuxu (ST 37) at 100 Hz for 1.05 s and 2 Hz for 2.85 s alternately, pulse width for 0.1 ms, 1 mA, 30 min/d, once a day, for 1 week. Cytokines IL-6, IL-1β, and TNF-α were analyzed by ELISA. The expressions of the P2Y1 receptor and pERK1/2 were analyzed by Western Blot and real-time PCR in the model and EA treated animals to explore the molecular mechanism of EA in inhibiting the activity of spinal cord dorsal horn (L6-S2 segment) astrocytes in rats with IBS visceral hypersensitivity. Results EA significantly reduced the behavioral abdominal withdrawal reflex score (AWRs) of IBS rats with visceral hypersensitivity induced by AA. For comparison, intrathecal injection of astrocytes activity inhibitor fluorocitrate (FCA) also reduced visceral hypersensitivity in IBS rats. EA at Zusanli and Shangjuxu inhibited the mRNA and protein expression of the glial fibrillary acidic protein (GFAP) and in rat spinal cord and reduced the release of inflammatory cytokines IL-6, IL-1, and TNF-α were analyzed by ELISA. The expressions of the P2Y1 receptor and pERK1/2 were analyzed by Western Blot and real-time PCR in the model and EA treated animals to explore the molecular mechanism of EA in inhibiting the activity of spinal cord dorsal horn (L6-S2 segment) astrocytes in rats with IBS visceral hypersensitivity. β, and TNF-μg, 10 μg, 10 Conclusion EA inhibited astrocyte activity in the spinal cord dorsal horn of rat with IBS visceral hypersensitivity by inhibiting the P2Y1 receptor and its downstream, PKC, and MAPK/ERK1/2 pathways.
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Shuai L, Li L, Sun J, Liao L, Duan Z, Li C, He X. Role of phospholipase C in banana in response to anthracnose infection. Food Sci Nutr 2020; 8:1038-1045. [PMID: 32148812 PMCID: PMC7020292 DOI: 10.1002/fsn3.1388] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 11/27/2019] [Accepted: 12/09/2019] [Indexed: 12/25/2022] Open
Abstract
Phospholipase C (PLC) plays an important role in plant immunity, and anthracnose caused by the Colletotrichum species is a common postharvest disease of the banana fruit. This study aims to evaluate the role of PLC in anthrax resistance in banana. The experimental group of banana samples was treated with a banana anthracnose conidia suspension, and the control group was treated with distilled water. After inoculation, the groups were sprayed with ethephon, and indicators, such as hardness and conductivity changes; PLC activity, 1,2-diacylglycerol (DAG) and phosphatidic acid (PA)content; and MaPLC-1and MaPLC-2 expression levels, were assessed at 0, 3, 6, 9, 12, and 15 days. Moreover, the expression levels of MaPLC-1 and MaPLC-2 were detected in various tissues. The hardness of banana fruits in the experimental group decreased faster than that in the control group. Furthermore, the conductivity was higher in the experimental group than in the control group. Regarding PLC activity, DAG, and PA content, bananas in the experimental group showed higher activities than those in the control group. Moreover, relatively higher expression of PLC mRNA was detected in anthracnose-inoculated tissues. The evaluation of MaPLC-1 and MaPLC-2 expression levels showed that the mature peel had the highest MaPLC-1 expression level. However, the MaPLC-2 gene was expressed at relatively low levels in the fruit and at relatively high levels in the flower organs. PLC might play a role in fruit ripening in response to anthracnose resistance.
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Affiliation(s)
- Liang Shuai
- Guangxi Crop Genetic Improvement and Biotechnology Key LaboratoryGuangxi Academy of Agricultural SciencesNanningChina
- College of Food and Biological Engineering/Institute of Food Science and Engineering TechnologyHezhou UniversityHezhouGuangxiChina
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
| | - Li Li
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
- Agro‐food Science and Technology Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
| | - Jian Sun
- Guangxi Crop Genetic Improvement and Biotechnology Key LaboratoryGuangxi Academy of Agricultural SciencesNanningChina
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
- Agro‐food Science and Technology Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
| | - Lingyan Liao
- College of Food and Biological Engineering/Institute of Food Science and Engineering TechnologyHezhou UniversityHezhouGuangxiChina
| | - Zhenhua Duan
- College of Food and Biological Engineering/Institute of Food Science and Engineering TechnologyHezhou UniversityHezhouGuangxiChina
| | - Changbao Li
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
- Agro‐food Science and Technology Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
| | - Xuemei He
- Guangxi Key Laboratory of Fruits and Vegetables Storage‐processing TechnologyGuangxi Academy of Agricultural SciencesNanningChina
- Agro‐food Science and Technology Research InstituteGuangxi Academy of Agricultural SciencesNanningChina
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Juneja DS, Nasuto S, Delivopoulos E. Fast and Efficient Differentiation of Mouse Embryonic Stem Cells Into ATP-Responsive Astrocytes. Front Cell Neurosci 2020; 13:579. [PMID: 32038173 PMCID: PMC6985097 DOI: 10.3389/fncel.2019.00579] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/16/2019] [Indexed: 12/25/2022] Open
Abstract
Astrocytes are multifunctional cells in the CNS, involved in the regulation of neurovascular coupling, the modulation of electrolytes, and the cycling of neurotransmitters at synapses. Induction of astrocytes from stem cells remains a largely underdeveloped area, as current protocols are time consuming, lack granularity in astrocytic subtype generation, and often are not as efficient as neural induction methods. In this paper we present an efficient method to differentiate astrocytes from mouse embryonic stem cells. Our technique uses a cell suspension protocol to produce embryoid bodies (EBs) that are neurally inducted and seeded onto laminin coated surfaces. Plated EBs attach to the surface and release migrating cells to their surrounding environment, which are further inducted into the astrocytic lineage, through an optimized, heparin-based media. Characterization and functional assessment of the cells consists of immunofluorescent labeling for specific astrocytic proteins and sensitivity to adenosine triphosphate (ATP) stimulation. Our experimental results show that even at the earliest stages of the protocol, cells are positive for astrocytic markers (GFAP, ALDH1L1, S100β, and GLAST) with variant expression patterns and purinergic receptors (P2Y). Generated astrocytes also exhibit differential Ca2+ transients upon stimulation with ATP, which evolve over the differentiation period. Metabotropic purinoceptors P2Y1R are expressed and we offer preliminary evidence that metabotropic purinoceptors contribute to Ca2+ transients. Our protocol is simple, efficient and fast, facilitating its use in multiple investigations, particularly in vitro studies of engineered neural networks.
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McDermott MI, Wang Y, Wakelam MJO, Bankaitis VA. Mammalian phospholipase D: Function, and therapeutics. Prog Lipid Res 2019; 78:101018. [PMID: 31830503 DOI: 10.1016/j.plipres.2019.101018] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 10/08/2019] [Accepted: 10/14/2019] [Indexed: 01/23/2023]
Abstract
Despite being discovered over 60 years ago, the precise role of phospholipase D (PLD) is still being elucidated. PLD enzymes catalyze the hydrolysis of the phosphodiester bond of glycerophospholipids producing phosphatidic acid and the free headgroup. PLD family members are found in organisms ranging from viruses, and bacteria to plants, and mammals. They display a range of substrate specificities, are regulated by a diverse range of molecules, and have been implicated in a broad range of cellular processes including receptor signaling, cytoskeletal regulation and membrane trafficking. Recent technological advances including: the development of PLD knockout mice, isoform-specific antibodies, and specific inhibitors are finally permitting a thorough analysis of the in vivo role of mammalian PLDs. These studies are facilitating increased recognition of PLD's role in disease states including cancers and Alzheimer's disease, offering potential as a target for therapeutic intervention.
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Affiliation(s)
- M I McDermott
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America.
| | - Y Wang
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America; Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, United States of America
| | - M J O Wakelam
- Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, United Kingdom
| | - V A Bankaitis
- Department of Molecular and Cellular Medicine, Texas A&M Health Science Center, College Station, TX 77843-1114, United States of America; Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843-2128, United States of America; Department of Chemistry, Texas A&M University, College Station, Texas 77840, United States of America
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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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16
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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: 889] [Impact Index Per Article: 148.2] [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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Purpura M, Rathmacher JA, Sharp MH, Lowery RP, Shields KA, Partl JM, Wilson JM, Jäger R. Oral Adenosine-5'-triphosphate (ATP) Administration Increases Postexercise ATP Levels, Muscle Excitability, and Athletic Performance Following a Repeated Sprint Bout. J Am Coll Nutr 2017; 36:177-183. [PMID: 28080323 DOI: 10.1080/07315724.2016.1246989] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Oral adenosine-5'-triphosphate (ATP) administration has failed to increase plasma ATP levels; however, chronic supplementation with ATP has shown to increase power, strength, lean body mass, and blood flow in trained athletes. The purpose of this study was to investigate the effects of ATP supplementation on postexercise ATP levels and on muscle activation and excitability and power following a repeated sprint bout. METHODS In a double-blind, placebo-controlled, randomized design, 42 healthy male individuals were given either 400 mg of ATP as disodium salt or placebo for 2 weeks prior to an exercise bout. During the exercise bout, muscle activation and excitability (ME, ratio of power output to muscle activation) and Wingate test peak power were measured during all sprints. ATP and metabolites were measured at baseline, after supplementation, and immediately following exercise. RESULTS Oral ATP supplementation prevented a drop in ATP, adenosine-5'-diphosphate (ADP), and adenosine-5'-monophosphate (AMP) levels postexercise (p < 0.05). No group by time interaction was observed for muscle activation. Following the supplementation period, muscle excitability significantly decreased in later bouts 8, 9, and 10 in the placebo group (-30.5, -28.3, and -27.9%, respectively; p < 0.02), whereas ATP supplementation prevented the decline in later bouts. ATP significantly increased Wingate peak power in later bouts compared to baseline (bout 8: +18.3%, bout 10: +16.3%). CONCLUSIONS Oral ATP administration prevents exercise-induced declines in ATP and its metabolite and enhances peak power and muscular excitability, which may be beneficial for sports requiring repeated high-intensity sprinting bouts.
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Affiliation(s)
| | - John A Rathmacher
- c Applied Science and Performance Institute , Tampa , Florida , USA.,d Metabolic Technologies Inc. , Ames , Iowa , USA.,e Department of Animal Sciences , Iowa State University , Ames , Iowa , USA
| | - Matthew H Sharp
- b Department of Health Sciences and Human Performance , The University of Tampa , Tampa , Florida , USA
| | - Ryan P Lowery
- c Applied Science and Performance Institute , Tampa , Florida , USA
| | - Kevin A Shields
- b Department of Health Sciences and Human Performance , The University of Tampa , Tampa , Florida , USA
| | - Jeremy M Partl
- b Department of Health Sciences and Human Performance , The University of Tampa , Tampa , Florida , USA
| | - Jacob M Wilson
- c Applied Science and Performance Institute , Tampa , Florida , USA
| | - Ralf Jäger
- a Increnovo LLC , Milwaukee , Wisconsin , USA
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18
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Adzic M, Stevanovic I, Josipovic N, Laketa D, Lavrnja I, Bjelobaba IM, Bozic I, Jovanovic M, Milosevic M, Nedeljkovic N. Extracellular ATP induces graded reactive response of astrocytes and strengthens their antioxidative defense in vitro. J Neurosci Res 2016; 95:1053-1066. [PMID: 27714837 DOI: 10.1002/jnr.23950] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Revised: 09/06/2016] [Accepted: 09/07/2016] [Indexed: 12/20/2022]
Abstract
It is widely accepted that adenosine triphosphate (ATP) acts as a universal danger-associated molecular pattern with several known mechanisms for immune cell activation. In the central nervous system, ATP activates microglia and astrocytes and induces a neuroinflammatory response. The aim of the present study was to describe responses of isolated astrocytes to increasing concentrations of ATP (5 µM to 1 mM), which were intended to mimic graded intensity of the extracellular stimulus. The results show that ATP induces graded activation response of astrocytes in terms of the cell proliferation, stellation, shape remodeling, and underlying actin and GFAP filament rearrangement, although the changes occurred without an apparent increase in GFAP and actin protein expression. On the other hand, ATP in the range of applied concentrations did not evoke IL-1β release from cultured astrocytes, nor did it modify the release from LPS and LPS+IFN-γ-primed astrocytes. ATP did not promote astrocyte migration in the wound-healing assay, nor did it increase production of reactive oxygen and nitrogen species and lipid peroxidation. Instead, ATP strengthened the antioxidative defense of astrocytes by inducing Cu/ZnSOD and MnSOD activities and by increasing their glutathione content. Our current results suggest that although ATP triggers several attributes of activated astrocytic phenotype with a magnitude that increases with the concentration, it is not sufficient to induce full-blown reactive phenotype of astrocytes in vitro. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Marija Adzic
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia.,Centre for Laser Microscopy, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Ivana Stevanovic
- Institute for Medical Research, Military Medical Academy, Belgrade, Serbia
| | - Natasa Josipovic
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Danijela Laketa
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Irena Lavrnja
- Institute for Biological Research "Sinisa Stankovic,", University of Belgrade, Belgrade, Serbia
| | - Ivana M Bjelobaba
- Institute for Biological Research "Sinisa Stankovic,", University of Belgrade, Belgrade, Serbia
| | - Iva Bozic
- Institute for Biological Research "Sinisa Stankovic,", University of Belgrade, Belgrade, Serbia
| | - Marija Jovanovic
- Institute for Biological Research "Sinisa Stankovic,", University of Belgrade, Belgrade, Serbia
| | - Milena Milosevic
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia.,Centre for Laser Microscopy, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Nadezda Nedeljkovic
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Belgrade, Serbia
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Abstract
OBJECTIVES Ischemic tissue injury contributes to significant morbidity and mortality and is implicated in a range of pathologic conditions, including but not limited to myocardial infarction, ischemic stroke, and acute kidney injury. The associated reperfusion phase is responsible for the activation of the innate and adaptive immune system, further accentuating inflammation. Adenosine triphosphate molecule has been implicated in various ischemic conditions, including stroke and myocardial infarction. STUDY SELECTION Adenosine triphosphate is a well-defined intracellular energy transfer and is commonly referred to as the body's "energy currency." However, Laboratory studies have demonstrated that extracellular adenosine triphosphate has the ability to initiate inflammation and is therefore referred to as a damage-associated molecular pattern. Purinergic receptors-dependent signaling, proinflammatory cytokine release, increased Ca influx into cells, and subsequent apoptosis have been shown to form a common underlying extracellular adenosine triphosphate molecular mechanism in ischemic organ injury. CONCLUSIONS In this review, we aim to discuss the molecular mechanisms behind adenosine triphosphate-mediated ischemic tissue injury and evaluate the role of extracellular adenosine triphosphate in ischemic injury in specific organs, in order to provide a greater understanding of the pathophysiology of this complex process. We also appraise potential future therapeutic strategies to limit damage in various organs, including the heart, brain, kidneys, and lungs.
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Cao L, Pu J, Scott RH, Ching J, McCaig CD. Physiological electrical signals promote chain migration of neuroblasts by up-regulating P2Y1 purinergic receptors and enhancing cell adhesion. Stem Cell Rev Rep 2015; 11:75-86. [PMID: 25096637 PMCID: PMC4333314 DOI: 10.1007/s12015-014-9524-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Neuroblasts migrate as directed chains of cells during development and following brain damage. A fuller understanding of the mechanisms driving this will help define its developmental significance and in the refinement of strategies for brain repair using transplanted stem cells. Recently, we reported that in adult mouse there are ionic gradients within the extracellular spaces that create an electrical field (EF) within the rostral migratory stream (RMS), and that this acts as a guidance cue for neuroblast migration. Here, we demonstrate an endogenous EF in brain slices and show that mimicking this by applying an EF of physiological strength, switches on chain migration in mouse neurospheres and in the SH-SY5Y neuroblastoma cell line. Firstly, we detected a substantial endogenous EF of 31.8 ± 4.5 mV/mm using microelectrode recordings from explants of the subventricular zone (SVZ). Pharmacological inhibition of this EF, effectively blocked chain migration in 3D cultures of SVZ explants. To mimic this EF, we applied a physiological EF and found that this increased the expression of N-cadherin and β-catenin, both of which promote cell-cell adhesion. Intriguingly, we found that the EF up-regulated P2Y purinoceptor 1 (P2Y1) to contribute to chain migration of neuroblasts through regulating the expression of N-cadherin, β-catenin and the activation of PKC. Our results indicate that the naturally occurring EF in brain serves as a novel stimulant and directional guidance cue for neuronal chain migration, via up-regulation of P2Y1.
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Affiliation(s)
- Lin Cao
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD UK
| | - Jin Pu
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD UK
| | - Roderick H. Scott
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD UK
| | - Jared Ching
- Department of Neurosurgery, Aberdeen Royal Infirmary, Aberdeen, AB25 2ZD UK
| | - Colin D. McCaig
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD UK
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Byun YS, Yoo YS, Kwon JY, Joo JS, Lim SA, Whang WJ, Mok JW, Choi JS, Joo CK. Diquafosol promotes corneal epithelial healing via intracellular calcium-mediated ERK activation. Exp Eye Res 2015; 143:89-97. [PMID: 26505315 DOI: 10.1016/j.exer.2015.10.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 10/15/2015] [Accepted: 10/16/2015] [Indexed: 12/27/2022]
Abstract
Diquafosol is known as a purinergic P2Y2 receptor (P2Y2R) agonist that stimulates water and mucin secretion from conjunctival epithelial cells and goblet cells, leading to tear film stability in dry eye. However, its effect on corneal epithelial healing has not yet been elucidated. The aim of the present study was to evaluate the effect of diquafosol on corneal epithelial healing in vivo and on P2Y2R-related downstream signaling pathways in vitro. We administered 3% diquafosol ophthalmic solution on 3 mm-diameter epithelial defects made in rat corneas and assessed the wound closure over time. Corneal epithelial healing was significantly accelerated in diquafosol-treated eyes compared to control eyes at 12 and 24 h. During wound healing, P2Y2R staining appeared stronger in the re-epithelized margin near the wound defect. To evaluate whether diquafosol stimulates epidermal growth factor receptor/extracellular-signal-regulated kinase (EGFR/ERK)-related cell proliferation and migration, simian virus 40-transfected human corneal epithelial (THCE) cells were used for in vitro experiments. Cell proliferation was accelerated by diquafosol at concentrations from 20 to 200 μM during 48 h, but inhibited at concentrations over 2000 μM. The intracellular calcium ([Ca(2+)]i) elevation was measured in diquafosol (100 μM)-stimulated cells using Fluo-4/AM ([Ca(2+)]i indicator). [Ca(2+)]i elevation was observed in diquafosol-stimulated cells regardless of the presence of calcium in media, and suramin pretreatment inhibited the calcium response. The effect of diquafosol on phosphorylation of EGFR, ERK and Akt, and cell migration was determined by western blotting and in vitro cell migration assay. Diquafosol induced phosphorylation of EGFR at 2 min post-stimulation, and phosphorylation of ERK at 5 min post-stimulation. Phosphorylation of ERK was attenuated in cells pretreated with suramin or BAPTA/AM ([Ca(2+)]i chelator), and partially with AG1478 (EGFR inhibitor). Likewise, diquafosol-treated cells showed acceleration of gap closure in cell migration assay, which was inhibited by suramin, BAPTA/AM, AG1478, and U0126 (MEK inhibitor). These studies demonstrate that diquafosol is effective in promoting corneal epithelial wound healing and that this effect may result from ERK-stimulated cell proliferation and migration via P2Y2R-mediated [Ca(2+)]i elevation.
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Affiliation(s)
- Yong-Soo Byun
- Department of Ophthalmology and Visual Science, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea; Catholic Institute of Visual Science, Catholic University of Korea, Seoul, Republic of Korea
| | - Young-Sik Yoo
- Catholic Institute of Visual Science, Catholic University of Korea, Seoul, Republic of Korea
| | - Ji-Young Kwon
- Catholic Institute of Visual Science, Catholic University of Korea, Seoul, Republic of Korea
| | - Jong-Soo Joo
- Department of Ophthalmology and Visual Science, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
| | - Sung-A Lim
- Department of Ophthalmology and Visual Science, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
| | - Woong-Joo Whang
- Department of Ophthalmology and Visual Science, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jee-Won Mok
- Catholic Institute of Visual Science, Catholic University of Korea, Seoul, Republic of Korea
| | - Jun-Sub Choi
- Catholic Institute of Visual Science, Catholic University of Korea, Seoul, Republic of Korea
| | - Choun-Ki Joo
- Department of Ophthalmology and Visual Science, College of Medicine, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Republic of Korea; Catholic Institute of Visual Science, Catholic University of Korea, Seoul, Republic of Korea.
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Brisevac D, Adzic M, Laketa D, Parabucki A, Milosevic M, Lavrnja I, Bjelobaba I, Sévigny J, Kipp M, Nedeljkovic N. Extracellular ATP Selectively Upregulates Ecto-Nucleoside Triphosphate Diphosphohydrolase 2 and Ecto-5'-Nucleotidase by Rat Cortical Astrocytes In Vitro. J Mol Neurosci 2015; 57:452-62. [PMID: 26080748 DOI: 10.1007/s12031-015-0601-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 06/08/2015] [Indexed: 02/07/2023]
Abstract
Extracellular ATP (eATP) acts as a danger-associated molecular pattern which induces reactive response of astrocytes after brain insult, including morphological remodeling of astrocytes, proliferation, chemotaxis, and release of proinflammatory cytokines. The responses induced by eATP are under control of ecto-nucleotidases, which catalyze sequential hydrolysis of ATP to adenosine. In the mammalian brain, ecto-nucleotidases comprise three enzyme families: ecto-nucleoside triphosphate diphosphohydrolases 1-3 (NTPDase1-3), ecto-nucleotide pyrophosphatase/phospodiesterases 1-3 (NPP1-3), and ecto-5'-nucleotidase (eN), which crucially determine ATP/adenosine ratio in the pericellular milieu. Altered expression of ecto-nucleotidases has been demonstrated in several experimental models of human brain dysfunctions. In the present study, we have explored the pattern of NTPDase1-3, NPP1-3, and eN expression by cultured cortical astrocytes challenged with 1 mmol/L ATP (eATP). At the transcriptional level, eATP upregulated expression of NTPDase1, NTPDase2, NPP2, and eN, while, at translational and functional levels, these were paralleled only by the induction of NTPDase2 and eN. Additionally, eATP altered membrane topology of eN, from clusters localized in membrane domains to continuous distribution along the cell membrane. Our results suggest that eATP, by upregulating NTPDase2 and eN and altering the enzyme membrane topology, affects local kinetics of ATP metabolism and signal transduction that may have important roles in the process related to inflammation and reactive gliosis.
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Affiliation(s)
- Dusica Brisevac
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia
| | - Marija Adzic
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia.,Center for Laser Microscopy, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Danijela Laketa
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia
| | - Ana Parabucki
- Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Belgrade, Serbia
| | - Milena Milosevic
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia.,Center for Laser Microscopy, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Irena Lavrnja
- Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Belgrade, Serbia
| | - Ivana Bjelobaba
- Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Belgrade, Serbia
| | - Jean Sévigny
- Département de microbiologie-infectiologie et d'immunologie, Faculté de Médecine, Université Laval, Québec, QC, G1V 0A6, Canada.,Centre de recherche du CHU de Québec Université Laval, Québec, QC, G1V 4G2, Canada
| | - Markus Kipp
- Institute of Neuroanatomy, Faculty of Medicine, RWTH Aachen University, Aachen, Germany.,Department of Anatomy II, Ludwig-Maximilians-University of Munich, Munich, Germany
| | - Nadezda Nedeljkovic
- Institute for Physiology and Biochemistry, Faculty of Biology, University of Belgrade, Studentski trg 3, Belgrade, 11001, Serbia.
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Jin H, Seo J, Eun SY, Joo YN, Park SW, Lee JH, Chang KC, Kim HJ. P2Y2 R activation by nucleotides promotes skin wound-healing process. Exp Dermatol 2015; 23:480-5. [PMID: 24816122 DOI: 10.1111/exd.12440] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/08/2014] [Indexed: 12/29/2022]
Abstract
P2Y2 R has been shown to be upregulated in a variety of tissues in response to stress or injury and to mediate tissue regeneration through its ability to activate multiple signalling pathways. This study aimed to investigate the role of P2Y2 R in the wound-healing process and the mechanisms by which P2Y2 R activation promotes wound healing in fibroblasts. The role of P2Y2 R in skin wound healing was examined using a full-thickness skin wound model in wildtype (WT) and P2Y2 R(-/-) mice and an in vitro scratch wound model in control or P2Y2 R siRNA-transfected fibroblasts. WT mice showed significantly decreased wound size compared with P2Y2 R(-/-) mice at day 14 post-wounding, and immunohistochemical analysis showed that a proliferation marker Ki67 and extracellular matrix (ECM)-related proteins VEGF, collagen I, fibronectin and α-SMA were overexpressed in WT mice, which were reduced in P2Y2 R(-/-) mice. Scratch-wounded fibroblasts increased ATP release, which peaked at 5 min. In addition, scratch wounding increased the level of P2Y2 R mRNA. Activation of P2Y2 R by ATP or UTP enhanced proliferation and migration of fibroblasts in in vitro scratch wound assays and were blocked by P2Y2 R siRNA. Finally, ATP or UTP also increased the levels of ECM-related proteins through the activation of P2Y2 R in fibroblasts. This study suggests that P2Y2 R may be a potential therapeutic target to promote wound healing in chronic wound diseases.
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Affiliation(s)
- Hana Jin
- Department of Pharmacology, School of Medicine, Institute of Health Sciences, Gyeongsang National University, Jinju, Korea
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Pathological potential of astroglial purinergic receptors. ADVANCES IN NEUROBIOLOGY 2014; 11:213-56. [PMID: 25236731 DOI: 10.1007/978-3-319-08894-5_11] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Acute brain injury and neurodegenerative disorders may result in astroglial activation. Astrocytes are able to determine the progression and outcome of these neuropathologies in a beneficial or detrimental way. Nucleotides, e.g. adenosine 5'-triphosphate (ATP), released after acute or chronic neuronal injury, are important mediators of glial activation and astrogliosis.Acute injury may cause significant changes in ATP balance, resulting in (1) a decline of intracellular ATP levels and (2) an increase in extracellular ATP concentrations via efflux from the intracellular space. The released ATP may have trophic effects, but can also act as a proinflammatory mediator or cytotoxic factor, inducing necrosis/apoptosis as a universal "danger" signal. Furthermore, ATP, primarily released from astrocytes, is a means of communication between neurons, glial cells, and intracerebral blood vessels.Astrocytes express a heterogeneous battery of purinergic ionotropic and metabotropic receptors (P2XRs and P2YRs, respectively) to respond to extracellular nucleotides.In this chapter, we summarize the contemporary knowledge on the pathological potential of P2Rs in relation to changes of astrocytic functions, determined by distinct molecular signaling cascades, in a variety of diseases. We discuss specific aspects of reactive astrogliosis, with respect to the involvement of prominent receptor subtypes, such as the P2X7 and P2Y1/2Rs. Examples of purinergic signaling of microglia, oligodendrocytes, and blood vessels under pathophysiological conditions will also be presented.The understanding of the pathological potential of purinergic signaling in "controlling and fine-tuning" of astrocytic responses is important for identifying possible therapeutic principles to treat acute and chronic central nervous system diseases.
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25
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Franke H, Illes P. Nucleotide signaling in astrogliosis. Neurosci Lett 2013; 565:14-22. [PMID: 24103370 DOI: 10.1016/j.neulet.2013.09.056] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Revised: 09/05/2013] [Accepted: 09/17/2013] [Indexed: 12/29/2022]
Abstract
Acute and chronic damage to the central nervous system (CNS) releases large quantities of ATP. Whereas the ATP concentration in the extracellular space is normally in the micromolar range, under these conditions it increases to millimolar levels. A number of ligand-gated cationic channels termed P2X receptors (7 mammalian subtypes), and G protein-coupled P2Y receptors (8 mammalian subtypes) are located at astrocytes, as confirmed by the measurement of the respective mRNA and protein. Activation of both the P2X7 and P2Y1,2 subtypes identified at astrocytes initiates astrogliosis isolating damaged brain areas from surrounding healthy cells and synthesizing neurotrophins and pleotrophins that participate in neuronal recovery. Astrocytes are considered as cells of high plasticity which may alter their properties in a culture medium. Therefore, recent work concentrates on investigating nucleotide effects at in situ (acute brain slices) and in vivo astrocytes. A wealth of data relates to the involvement of purinergic mechanisms in astrogliosis induced by acute CNS injury such as mechanical trauma and hypoxia/ischemia. The released ATP may act within minutes as an excitotoxic molecule; at a longer time-scale within days it causes neuroinflammation. These effects sum up as necrosis/apoptosis on the one hand and proliferation on the other. Although the role of nucleotides in chronic neurodegenerative illnesses is not quite clear, it appears that they aggravate the consequences of the primary disease. Epilepsy and neuropathic pain are also associated with the release of ATP and a pathologic glia-neuron interaction leading to astrogliosis and cell death. In view of these considerations, P2 receptor antagonists may open new therapeutic vistas in all forms of acute and chronic CNS damage.
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Affiliation(s)
- Heike Franke
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany
| | - Peter Illes
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, 04107 Leipzig, Germany.
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26
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FOXO3a involvement in the release of TNF-α stimulated by ATP in spinal cord astrocytes. J Mol Neurosci 2013; 51:792-804. [PMID: 23860688 DOI: 10.1007/s12031-013-0067-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Accepted: 07/02/2013] [Indexed: 12/20/2022]
Abstract
Spinal cord injury is characterized by an inflammatory response that includes the increased expression of several cytokines and chemokines. Extracellular adenosine triphosphate (ATP) acts as a critical endogenous signaling molecule in inflammation and immunity. However, the molecular and cellular mechanisms of the proinflammatory cytokines stimulated by ATP are poorly understood. Mammalian forkhead members of the class O (FOXO) are involved in a variety of signaling pathways. In this study, we have found that ATP could selectively decrease the expression of FOXO1 and FOXO3a via the phosphorylation of epidermal growth factor receptor (EGFR) and Akt in spinal cord astrocytes. However, ATP had no effect on the expression of FOXO4 and FOXO6, and EGFR, Akt, and ERK1/2 all involve in the release of interleukin (IL)-6 and tumor necrosis factor-α (TNF-α) induced by ATP. In addition, we have researched that the overexpressed FOXO3a could specially inhibit the release of TNF-α increased by ATP, but the level of IL-6 induced by ATP was not decreased. Meanwhile, there was no change in the release of IL-6 and TNF-α after FOXO1 was overexpressed. Understanding the critical role of FOXO3a in astrocytes stimulated by ATP may provide a potential target for therapeutic intervention after spinal cord injury.
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27
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New approaches to thyroid hormones and purinergic signaling. J Thyroid Res 2013; 2013:434727. [PMID: 23956925 PMCID: PMC3730180 DOI: 10.1155/2013/434727] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 06/20/2013] [Indexed: 12/22/2022] Open
Abstract
It is known that thyroid hormones influence a wide variety of events at the molecular, cellular, and functional levels. Thyroid hormones (TH) play pivotal roles in growth, cell proliferation, differentiation, apoptosis, development, and metabolic homeostasis via thyroid hormone receptors (TRs) by controlling the expression of TR target genes. Most of these effects result in pathological and physiological events and are already well described in the literature. Even so, many recent studies have been devoted to bringing new information on problems in controlling the synthesis and release of these hormones and to elucidating mechanisms of the action of these hormones unconventionally. The purinergic system was recently linked to thyroid diseases, including enzymes, receptors, and enzyme products related to neurotransmitter release, nociception, behavior, and other vascular systems. Thus, throughout this text we intend to relate the relationship between the TH in physiological and pathological situations with the purinergic signaling.
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Imura Y, Morizawa Y, Komatsu R, Shibata K, Shinozaki Y, Kasai H, Moriishi K, Moriyama Y, Koizumi S. Microglia release ATP by exocytosis. Glia 2013; 61:1320-30. [PMID: 23832620 DOI: 10.1002/glia.22517] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Revised: 04/09/2013] [Accepted: 04/12/2013] [Indexed: 11/07/2022]
Abstract
Microglia survey the brain environment by sensing several types of diffusible molecules, among which extracellular nucleotides released/leaked from damaged cells have central roles. Microglia sense ATP or other nucleotides by multiple P2 receptors, after which they change into several different phenotypes. However, so far, it is largely unknown whether microglia themselves release ATP and, if so, by what mechanism. Here we show that exocytosis is the mechanism by which microglia release ATP. When we stimulated microglia with ionomycin, they released ATP and the release was dependent on Ca²⁺, vesicular H⁺-ATPase, or SNAREs but independent of connexin/pannexin hemichannels. VNUT was found to be expressed in microglia and exhibited no colocalization with lysosome. We also visualized the exocytosis of ATP by a quinacrine-based fluorescent time-lapse imaging. Moreover, we found that lipopolysaccharide increased the ionomycin-induced release of ATP, which was dependent on the increase in VNUT. Taken together, our data suggested that exocytosis is the mechanism of ATP release from microglia. When activated, they would release ATP by increasing VNUT-dependent exocytotic mechanisms.
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Affiliation(s)
- Yoshio Imura
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Shimokato, Chuo, Yamanashi, Japan
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29
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Scott SA, Xiang Y, Mathews TP, Cho HP, Myers DS, Armstrong MD, Tallman KA, O'Reilly MC, Lindsley CW, Brown HA. Regulation of phospholipase D activity and phosphatidic acid production after purinergic (P2Y6) receptor stimulation. J Biol Chem 2013; 288:20477-87. [PMID: 23723068 DOI: 10.1074/jbc.m113.451708] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Phosphatidic acid (PA) is a lipid second messenger located at the intersection of several lipid metabolism and cell signaling events including membrane trafficking, survival, and proliferation. Generation of signaling PA has long been primarily attributed to the activation of phospholipase D (PLD). PLD catalyzes the hydrolysis of phosphatidylcholine into PA. A variety of both receptor-tyrosine kinase and G-protein-coupled receptor stimulations have been shown to lead to PLD activation and PA generation. This study focuses on profiling the PA pool upon P2Y6 receptor signaling manipulation to determine the major PA producing enzymes. Here we show that PLD, although highly active, is not responsible for the majority of stable PA being produced upon UDP stimulation of the P2Y6 receptor and that PA levels are tightly regulated. By following PA flux in the cell we show that PLD is involved in an initial increase in PA upon receptor stimulation; however, when PLD is blocked, the cell compensates by increasing PA production from other sources. We further delineate the P2Y6 signaling pathway showing that phospholipase Cβ3 (PLCβ3), PLCδ1, DGKζ and PLD are all downstream of receptor activation. We also show that DGKζ is a novel negative regulator of PLD activity in this system that occurs through an inhibitory mechanism with PKCα. These results further define the downstream events resulting in PA production in the P2Y6 receptor signaling pathway.
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Affiliation(s)
- Sarah A Scott
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, USA
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30
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Astrocytes protect neurons against methylmercury via ATP/P2Y(1) receptor-mediated pathways in astrocytes. PLoS One 2013; 8:e57898. [PMID: 23469098 PMCID: PMC3585279 DOI: 10.1371/journal.pone.0057898] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 01/27/2013] [Indexed: 11/19/2022] Open
Abstract
Methylmercury (MeHg) is a well known environmental pollutant that induces serious neuronal damage. Although MeHg readily crosses the blood-brain barrier, and should affect both neurons and glial cells, how it affects glia or neuron-to-glia interactions has received only limited attention. Here, we report that MeHg triggers ATP/P2Y1 receptor signals in astrocytes, thereby protecting neurons against MeHg via interleukin-6 (IL-6)-mediated pathways. MeHg increased several mRNAs in astrocytes, among which IL-6 was the highest. For this, ATP/P2Y1 receptor-mediated mechanisms were required because the IL-6 production was (i) inhibited by a P2Y1 receptor antagonist, MRS2179, (ii) abolished in astrocytes obtained from P2Y1 receptor-knockout mice, and (iii) mimicked by exogenously applied ATP. In addition, (iv) MeHg released ATP by exocytosis from astrocytes. As for the intracellular mechanisms responsible for IL-6 production, p38 MAP kinase was involved. MeHg-treated astrocyte-conditioned medium (ACM) showed neuro-protective effects against MeHg, which was blocked by anti-IL-6 antibody and was mimicked by the application of recombinant IL-6. As for the mechanism of neuro-protection by IL-6, an adenosine A1 receptor-mediated pathway in neurons seems to be involved. Taken together, when astrocytes sense MeHg, they release ATP that autostimulates P2Y1 receptors to upregulate IL-6, thereby leading to A1 receptor-mediated neuro-protection against MeHg.
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31
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MacMillan D, Kennedy C, McCarron JG. ATP inhibits Ins(1,4,5)P3-evoked Ca2+ release in smooth muscle via P2Y1 receptors. J Cell Sci 2012; 125:5151-8. [PMID: 22899721 PMCID: PMC5704898 DOI: 10.1242/jcs.108498] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Adenosine 5′-triphosphate (ATP) mediates a variety of biological functions following nerve-evoked release, via activation of either G-protein-coupled P2Y- or ligand-gated P2X receptors. In smooth muscle, ATP, acting via P2Y receptors (P2YR), may act as an inhibitory neurotransmitter. The underlying mechanism(s) remain unclear, but have been proposed to involve the production of inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] by phospholipase C (PLC), to evoke Ca2+ release from the internal store and stimulation of Ca2+-activated potassium (KCa) channels to cause membrane hyperpolarization. This mechanism requires Ca2+ release from the store. However, in the present study, ATP evoked transient Ca2+ increases in only ~10% of voltage-clamped single smooth muscle cells. These results do not support activation of KCa as the major mechanism underlying inhibition of smooth muscle activity. Interestingly, ATP inhibited Ins(1,4,5)P3-evoked Ca2+ release in cells that did not show a Ca2+ rise in response to purinergic activation. The reduction in Ins(1,4,5)P3-evoked Ca2+ release was not mimicked by adenosine and therefore, cannot be explained by hydrolysis of ATP to adenosine. The reduction in Ins(1,4,5)P3-evoked Ca2+ release was, however, also observed with its primary metabolite, ADP, and blocked by the P2Y1R antagonist, MRS2179, and the G protein inhibitor, GDPβS, but not by PLC inhibition. The present study demonstrates a novel inhibitory effect of P2Y1R activation on Ins(1,4,5)P3-evoked Ca2+ release, such that purinergic stimulation acts to prevent Ins(1,4,5)P3-mediated increases in excitability in smooth muscle and promote relaxation.
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Affiliation(s)
- D MacMillan
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK.
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32
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Franke H, Verkhratsky A, Burnstock G, Illes P. Pathophysiology of astroglial purinergic signalling. Purinergic Signal 2012; 8:629-57. [PMID: 22544529 DOI: 10.1007/s11302-012-9300-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 02/01/2012] [Indexed: 12/13/2022] Open
Abstract
Astrocytes are fundamental for central nervous system (CNS) physiology and are the fulcrum of neurological diseases. Astroglial cells control development of the nervous system, regulate synaptogenesis, maturation, maintenance and plasticity of synapses and are central for nervous system homeostasis. Astroglial reactions determine progression and outcome of many neuropathologies and are critical for regeneration and remodelling of neural circuits following trauma, stroke, ischaemia or neurodegenerative disorders. They secrete multiple neurotransmitters and neurohormones to communicate with neurones, microglia and the vascular walls of capillaries. Signalling through release of ATP is the most widespread mean of communication between astrocytes and other types of neural cells. ATP serves as a fast excitatory neurotransmitter and has pronounced long-term (trophic) roles in cell proliferation, growth, and development. During pathology, ATP is released from damaged cells and acts both as a cytotoxic factor and a proinflammatory mediator, being a universal "danger" signal. In this review, we summarise contemporary knowledge on the role of purinergic receptors (P2Rs) in a variety of diseases in relation to changes of astrocytic functions and nucleotide signalling. We have focussed on the role of the ionotropic P2X and metabotropic P2YRs working alone or in concert to modify the release of neurotransmitters, to activate signalling cascades and to change the expression levels of ion channels and protein kinases. All these effects are of great importance for the initiation, progression and maintenance of astrogliosis-the conserved and ubiquitous glial defensive reaction to CNS pathologies. We highlighted specific aspects of reactive astrogliosis, especially with respect to the involvement of the P2X(7) and P2Y(1)R subtypes. Reactive astrogliosis exerts both beneficial and detrimental effects in a context-specific manner determined by distinct molecular signalling cascades. Understanding the role of purinergic signalling in astrocytes is critical to identifying new therapeutic principles to treat acute and chronic neurological diseases.
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Affiliation(s)
- Heike Franke
- Rudolf Boehm Institute of Pharmacology and Toxicology, University of Leipzig, Härtelstrasse 16-18, 04107, Leipzig, Germany.
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33
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Koganti S, Snyder R, Thekkumkara T. Pharmacologic effects of 2-methoxyestradiol on angiotensin type 1 receptor down-regulation in rat liver epithelial and aortic smooth muscle cells. ACTA ACUST UNITED AC 2012; 9:76-93. [PMID: 22366193 DOI: 10.1016/j.genm.2012.01.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 01/04/2012] [Accepted: 01/20/2012] [Indexed: 11/18/2022]
Abstract
BACKGROUND Delayed onset of cardiovascular disease (CVD) in female patients is not well understood, but could be due in part to the protective effect of estrogen before menopause. Experimental studies have identified the angiotensin type 1 receptor (AT1R) as a key factor in the progression of CVD. OBJECTIVE We examined the effects of the estrogen metabolite 2-methoxyestradiol (2ME2) on AT1R expression. METHODS Rat liver cells were exposed to 2ME2 for 24 hours, and angiotensin II (AngII) binding and AT1R mRNA expressions were assessed. RESULTS In the presence of 2ME2, cells exhibited significant down-regulation of AngII binding that was both dose and time dependent, independent of estrogen receptors (ERα/ERβ). Down-regulation of AngII binding was AT1R specific, with no change in receptor affinity. Under similar conditions, we observed lower expression of AT1R mRNA, significant inhibition of AngII-mediated increase in intracellular Ca(2+), and increased phosphorylation of ERK1/2. Pretreatment of cells with the MEK inhibitor PD98059 prevented 2ME2-induced ERK1/2 phosphorylation and down-regulation of AT1R expression, which suggests that the observed inhibitory effect is mediated through ERK1/2 signaling intermediates. Similar analyses in stably transfected CHO (Chinese hamster ovary) cell lines with a constitutively active cytomegalovirus promoter showed no change in AT1R expression, which suggests that 2ME2-mediated effects are through transcriptional regulation. The effects of 2ME2 on AT1R down-regulation through ERK1/2 were consistently reproduced in primary rat aortic smooth muscle cells. CONCLUSIONS Because AT1R has a critical role in the control of CVD, 2ME2-induced changes in receptor expression may provide beneficial effects to the cardiovascular and other systems.
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MESH Headings
- 2-Methoxyestradiol
- Angiotensin II/drug effects
- Angiotensin II/genetics
- Angiotensin II/metabolism
- Animals
- Aorta/drug effects
- Cricetinae
- Down-Regulation
- Estradiol/analogs & derivatives
- Estradiol/pharmacology
- Female
- Gene Expression Regulation/drug effects
- Humans
- Liver/drug effects
- Male
- Microscopy, Fluorescence
- Myocytes, Smooth Muscle/drug effects
- RNA, Messenger/metabolism
- Rats
- Receptor, Angiotensin, Type 1/drug effects
- Receptor, Angiotensin, Type 2/drug effects
- Receptor, Angiotensin, Type 2/genetics
- Receptor, Angiotensin, Type 2/metabolism
- Signal Transduction/drug effects
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Affiliation(s)
- Sivaramakrishna Koganti
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA
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34
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Ciarcia R, Vitiello MT, Galdiero M, Pacilio C, Iovane V, d'Angelo D, Pagnini D, Caparrotti G, Conti D, Tomei V, Florio S, Giordano A. Imatinib treatment inhibit IL-6, IL-8, NF-KB and AP-1 production and modulate intracellular calcium in CML patients. J Cell Physiol 2012; 227:2798-803. [DOI: 10.1002/jcp.23029] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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35
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Martiáñez T, Carrascal M, Lamarca A, Segura M, Durany N, Masgrau R, Abian J, Gella A. UTP affects the Schwannoma cell line proteome through P2Y receptors leading to cytoskeletal reorganisation. Proteomics 2011; 12:145-56. [PMID: 22065602 DOI: 10.1002/pmic.201100187] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 09/09/2011] [Accepted: 10/19/2011] [Indexed: 12/23/2022]
Abstract
Glial cells in the peripheral nervous system, such as Schwann cells, respond to nucleotides, which play an important role in axonal regeneration and myelination. Metabotropic P2Y receptor agonists are promising therapeutic molecules for peripheral neuropathies. Nevertheless, the proteomic mechanisms involved in nucleotide action on Schwann cells remain unknown. Here, we studied intracellular protein changes in RT4-D6P2T Schwann cells after treatment with nucleotides and Nucleo CMP Forte (CMPF), a nucleotide-based drug. After treatment with CMPF, 2-D DIGE revealed 11 differential gel spots, which were all upregulated. Among these, six different proteins were identified by MS. Some of these proteins are involved in actin remodelling (actin-related protein, Arp3), membrane vesicle transport (Rab GDP dissociation inhibitor β, Rab GDI), and the endoplasmic reticulum stress response (protein disulfide isomerase A3, PDI), which are hallmarks of a possible P2Y receptor signalling pathway. Expression of P2Y receptors in RT4-D6P2T cells was demonstrated by RT-PCR and a transient elevation of intracellular calcium measured in response to UTP. Actin reorganisation was visualized after UTP treatment using phalloidin-FITC staining and was blocked by the P2Y antagonist suramin, which also inhibited Arp3, Rab GDI, and PDI protein upregulation. Our data indicate that extracellular UTP interacts with Schwann P2Y receptors and activates molecular machinery that induces changes in the glial cell cytoskeleton.
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Affiliation(s)
- Tánia Martiáñez
- Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya, Josep Trueta s/n, Sant Cugat del Vallès, Spain
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Boucher I, Kehasse A, Marcincin M, Rich C, Rahimi N, Trinkaus-Randall V. Distinct activation of epidermal growth factor receptor by UTP contributes to epithelial cell wound repair. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:1092-105. [PMID: 21356361 DOI: 10.1016/j.ajpath.2010.11.060] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2010] [Revised: 10/13/2010] [Accepted: 11/23/2010] [Indexed: 01/05/2023]
Abstract
The release of nucleotides after injury activates purinergic receptors, leading to phosphorylation of site-specific residues on epidermal growth factor receptor (EGFR). To elucidate the differences between the injury-induced response and that induced by exogenous EGF, we examined recruitment of docking proteins, internalization of EGFR, and migration after injury. Injury induced by scratch wounds or stimulation by addition of UTP caused a brief internalization of EGFR, which paralleled the lesser association with growth factor receptor-bound protein 2 (Grb2) and phosphorylation of EGFR. The internalization caused by EGF was sustained and detected for longer than 60 minutes and correlated with phosphorylation of the receptor. The EGF caused recruitment of Grb2, phospholipase C-γ-1 (PLCγ1), Shc, and Src to EGFR. Glutathione S-transferase pull downs were performed, and glutathione S-transferase-PLCγ1 showed binding of Grb2 when stimulated with EGF but not with UTP or injury. Furthermore, UTP did not induce PLCγ1 phosphorylation, and the phosphorylation induced by EGF was attenuated by costimulation with UTP. The response to heparin-binding EGF was equivalent to that of EGF. Site-directed mutagenesis showed that phosphorylation of Y1068 and Y1086 of EGFR is required for repair. Together, our results show that injury and activation of purinergic receptors and direct activation of EGFR via EGF induce distinct downstream pathways.
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Affiliation(s)
- Ilene Boucher
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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Quintas C, Fraga S, Gonçalves J, Queiroz G. Opposite modulation of astroglial proliferation by adenosine 5'-O-(2-thio)-diphosphate and 2-methylthioadenosine-5'-diphosphate: mechanisms involved. Neuroscience 2011; 182:32-42. [PMID: 21419195 DOI: 10.1016/j.neuroscience.2011.03.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Revised: 03/01/2011] [Accepted: 03/02/2011] [Indexed: 01/26/2023]
Abstract
The contribution of P2Y(12,13) receptors to astroglial proliferation was investigated by testing the effects of two agonists with high affinity for these receptors, adenosine 5'-O-(2-thio)-diphosphate (ADPβS) and 2-methylthioadenosine-5'-diphosphate (2-MeSADP), in the incorporation of [(3)H]-thymidine. The effect of ATP, an endogenous inducer of astroglial proliferation, was also investigated. ADPβS and ATP (0.01-1 mM) increased astroglial proliferation up to 282%, an effect inhibited by the P2Y(1) receptor antagonist MRS 2179 (30 μM). The P2Y(12) receptor antagonists MRS 2395 (10 μM) and AR-C 66096 (10 μM) also reduced ADPβS proliferative effect, whereas the effect of ATP was attenuated by the A(2A) and A(2B) receptor antagonists SCH 58261 (30 nM) and MRS 1706 (10 nM), respectively. Studies of the signalling pathway activated showed that ADPβS effect was attenuated by pertussis toxin and by inhibition of phopholipase C (PLC), protein kinase C (PKC) and extracellular signal-regulated kinase1/2 (ERK1/2). The effect of ATP was also attenuated by inhibition of protein kinase A (PKA). The agonist 2-MeSADP (0.001-10 μM) had no effect in astroglial proliferation, but at higher concentrations (0.1-1 mM) it inhibited up to 63%, by mechanisms independent of P2Y(1,12,13) receptors activation. It was metabolised into 2-methylthioadenosine (2-MeSADO), the metabolite responsible for inhibition of astroglial proliferation. The effect of 2-MeSADO (0.1 mM) was attenuated by the A(3) receptors antagonist MRS 1523 (10 μM) and by the inhibitor of nucleoside transporters uridine (0.3 mM). 2-MeSADO did not induce apoptosis but increased lactate dehydrogenase release, an indicator of necrotic cell death. Astroglial proliferation induced by ADPβS was mediated by P2Y(1) and P2Y(12) receptors, leading to activation of PLC-PKC-ERK1/2 signalling pathway. The ATP proliferative effect was also mediated by PKA, supporting the contribution of the A(2) receptors. 2-MeSADP inhibition of astroglial proliferation depended on its conversion into 2-MeSADO, which activated A(3) receptors, blocked [(3)H]-thymidine uptake by astrocytes and led to cell death.
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Affiliation(s)
- C Quintas
- Department of Drug Sciences, Faculty of Pharmacy, Centro de Química Fina e Biotecnologia da Universidade de Lisboa e Centro de Química da Universidade do Porto (REQUIMTE), University of Porto, Porto, Portugal
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38
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Tsuda M, Kohro Y, Yano T, Tsujikawa T, Kitano J, Tozaki-Saitoh H, Koyanagi S, Ohdo S, Ji RR, Salter MW, Inoue K. JAK-STAT3 pathway regulates spinal astrocyte proliferation and neuropathic pain maintenance in rats. ACTA ACUST UNITED AC 2011; 134:1127-39. [PMID: 21371995 DOI: 10.1093/brain/awr025] [Citation(s) in RCA: 222] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuropathic pain, a debilitating pain condition, is a common consequence of damage to the nervous system. Optimal treatment of neuropathic pain is a major clinical challenge because the underlying mechanisms remain unclear and currently available treatments are frequently ineffective. Emerging lines of evidence indicate that peripheral nerve injury converts resting spinal cord glia into reactive cells that are required for the development and maintenance of neuropathic pain. However, the mechanisms underlying reactive astrogliosis after nerve injury are largely unknown. In the present study, we investigated cell proliferation, a critical process in reactive astrogliosis, and determined the temporally restricted proliferation of dorsal horn astrocytes in rats with spinal nerve injury, a well-known model of neuropathic pain. We found that nerve injury-induced astrocyte proliferation requires the Janus kinase-signal transducers and activators of transcription 3 signalling pathway. Nerve injury induced a marked signal transducers and activators of transcription 3 nuclear translocation, a primary index of signal transducers and activators of transcription 3 activation, in dorsal horn astrocytes. Intrathecally administering inhibitors of Janus kinase-signal transducers and activators of transcription 3 signalling to rats with nerve injury reduced the number of proliferating dorsal horn astrocytes and produced a recovery from established tactile allodynia, a cardinal symptom of neuropathic pain that is characterized by pain hypersensitivity evoked by innocuous stimuli. Moreover, recovery from tactile allodynia was also produced by direct suppression of dividing astrocytes by intrathecal administration of the cell cycle inhibitor flavopiridol to nerve-injured rats. Together, these results imply that the Janus kinase-signal transducers and activators of transcription 3 signalling pathway are critical transducers of astrocyte proliferation and maintenance of tactile allodynia and may be a therapeutic target for neuropathic pain.
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Affiliation(s)
- Makoto Tsuda
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
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Köles L, Leichsenring A, Rubini P, Illes P. P2 receptor signaling in neurons and glial cells of the central nervous system. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2011; 61:441-93. [PMID: 21586367 DOI: 10.1016/b978-0-12-385526-8.00014-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Purine and pyrimidine nucleotides are extracellular signaling molecules in the central nervous system (CNS) leaving the intracellular space of various CNS cell types via nonexocytotic mechanisms. In addition, ATP is a neuro-and gliotransmitter released by exocytosis from neurons and neuroglia. These nucleotides activate P2 receptors of the P2X (ligand-gated cationic channels) and P2Y (G protein-coupled receptors) types. In mammalians, seven P2X and eight P2Y receptor subunits occur; three P2X subtypes form homomeric or heteromeric P2X receptors. P2Y subtypes may also hetero-oligomerize with each other as well as with other G protein-coupled receptors. P2X receptors are able to physically associate with various types of ligand-gated ion channels and thereby to interact with them. The P2 receptor homomers or heteromers exhibit specific sensitivities against pharmacological ligands and have preferential functional roles. They may be situated at both presynaptic (nerve terminals) and postsynaptic (somatodendritic) sites of neurons, where they modulate either transmitter release or the postsynaptic sensitivity to neurotransmitters. P2 receptors exist at neuroglia (e.g., astrocytes, oligodendrocytes) and microglia in the CNS. The neuroglial P2 receptors subserve the neuron-glia cross talk especially via their end-feets projecting to neighboring synapses. In addition, glial networks are able to communicate through coordinated oscillations of their intracellular Ca(2+) over considerable distances. P2 receptors are involved in the physiological regulation of CNS functions as well as in its pathophysiological dysregulation. Normal (motivation, reward, embryonic and postnatal development, neuroregeneration) and abnormal regulatory mechanisms (pain, neuroinflammation, neurodegeneration, epilepsy) are important examples for the significance of P2 receptor-mediated/modulated processes.
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Affiliation(s)
- Laszlo Köles
- Rudolph-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, Germany
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Yamazaki D, Kito H, Yamamoto S, Ohya S, Yamamura H, Asai K, Imaizumi Y. Contribution of K(ir)2 potassium channels to ATP-induced cell death in brain capillary endothelial cells and reconstructed HEK293 cell model. Am J Physiol Cell Physiol 2010; 300:C75-86. [PMID: 20980552 DOI: 10.1152/ajpcell.00135.2010] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cellular turnover of brain capillary endothelial cells (BCECs) by the balance of cell proliferation and death is essential for maintaining the homeostasis of the blood-brain barrier. Stimulation of metabotropic ATP receptors (P2Y) transiently increased intracellular Ca²(+) concentration ([Ca²(+)](i)) in t-BBEC 117, a cell line derived from bovine BCECs. The [Ca²(+)](i) rise induced membrane hyperpolarization via the activation of apamin-sensitive small-conductance Ca²(+)-activated K(+) channels (SK2) and enhanced cell proliferation in t-BBEC 117. Here, we found anomalous membrane hyperpolarization lasting for over 10 min in response to ATP in ∼15% of t-BBEC 117, in which inward rectifier K(+) channel (K(ir)2.1) was extensively expressed. Once anomalous hyperpolarization was triggered by ATP, it was removed by Ba²(+) but not by apamin. Prolonged exposure to ATPγS increased the relative population of t-BBEC 117, in which the expression of K(ir)2.1 mRNAs was significantly higher and Ba²(+)-sensitive anomalous hyperpolarization was observed. The cultivation of t-BBEC 117 in serum-free medium also increased this population and reduced the cell number. The reduction of cell number was enhanced by the addition of ATPγS and the enhancement was antagonized by Ba²(+). In the human embryonic kidney 293 cell model, where SK2 and K(ir)2.1 were heterologously coexpressed, [Ca²(+)](i) rise by P2Y stimulation triggered anomalous hyperpolarization and cell death. In conclusion, P2Y stimulation in BCECs enhances cell proliferation by SK2 activation in the majority of cells but also triggers cell death in a certain population showing a substantial expression of K(ir)2.1. This dual action of P2Y stimulation may effectively facilitate BCEC turnover.
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Affiliation(s)
- Daiju Yamazaki
- Department of Molecular and Cellular Pharmacology, Nagoya City University, Japan
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Rudkouskaya A, Chernoguz A, Haskew-Layton RE, Mongin AA. Two conventional protein kinase C isoforms, alpha and beta I, are involved in the ATP-induced activation of volume-regulated anion channel and glutamate release in cultured astrocytes. J Neurochem 2010; 105:2260-70. [PMID: 18315563 DOI: 10.1111/j.1471-4159.2008.05312.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Volume-regulated anion channels (VRACs) are activated by cell swelling and are permeable to inorganic and small organic anions, including the excitatory amino acids glutamate and aspartate. In astrocytes, ATP potently enhances VRAC activity and glutamate release via a P2Y receptor-dependent mechanism. Our previous pharmacological study identified protein kinase C (PKC) as a major signaling enzyme in VRAC regulation by ATP. However, conflicting results obtained with potent PKC blockers prompted us to re-evaluate the involvement of PKC in regulation of astrocytic VRACs by using small interfering RNA (siRNA) and pharmacological inhibitors that selectively target individual PKC isoforms. In primary rat astrocyte cultures, application of hypoosmotic medium (30% reduction in osmolarity) and 20 microM ATP synergistically increased the release of excitatory amino acids, measured with a non-metabolized analog of L-glutamate, D-[(3)H]aspartate. Both Go6976, the selective inhibitor of Ca(2+)-sensitive PKCalpha, betaI/II, and gamma, and MP-20-28, a cell permeable pseudosubstrate inhibitory peptide of PKCalpha and betaI/II, reduced the effects of ATP on D-[(3)H]aspartate release by approximately 45-55%. Similar results were obtained with a mixture of siRNAs targeting rat PKCalpha and betaI. Surprisingly, down-regulation of individual alpha and betaI PKC isozymes by siRNA was completely ineffective. These data suggest that ATP regulates VRAC activity and volume-sensitive excitatory amino acid release via cooperative activation of PKCalpha and betaI.
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Affiliation(s)
- Alena Rudkouskaya
- Center of Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208
| | - Artur Chernoguz
- Center of Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208
| | - Renée E Haskew-Layton
- Burke/Cornell Medical Research Institute of Cornell University, White Plains, NY 10605
| | - Alexander A Mongin
- Center of Neuropharmacology and Neuroscience, Albany Medical College, Albany, NY 12208
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Rodríguez-Zayas AE, Torrado AI, Miranda JD. P2Y2 receptor expression is altered in rats after spinal cord injury. Int J Dev Neurosci 2010; 28:413-21. [PMID: 20619335 DOI: 10.1016/j.ijdevneu.2010.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Revised: 06/22/2010] [Accepted: 07/01/2010] [Indexed: 12/17/2022] Open
Abstract
Spinal cord injury increases inhibitory factors that may restrict neurite outgrowth after trauma. The expression of repulsive molecules in reactive astrocytes and the formation of the glial scar at the injury site produce the non-permissive environment for axonal regeneration. However, the mechanism that triggers this astrogliotic response is unknown. The release of nucleotides has been linked to this hypertrophic state. Our goal is to investigate the temporal profile of P2Y(2) nucleotide receptor after spinal cord injury in adult female Sprague-Dawley rats. Molecular biology, immunofluorescence studies, and Western Blots were used to evaluate the temporal profile (2, 4, 7, 14, and 28 days post-injury) of this receptor in rats injured at the T-10 level using the NYU impactor device. Real time RT-PCR showed a significant increase of P2Y(2) mRNA after 2 days post-injury that continues throughout 28 days post-injury. Double labeling studies localized P2Y(2) immunoreactivity in neuronal cell bodies, axons, macrophages, oligodendrocytes and reactive astrocytes. Immunofluorescence studies also demonstrated a low level of P2Y(2) receptor in sham samples, which increased after injury in glial fibrillary acidic protein positive cells. Western Blot performed with contused spinal cord protein samples revealed an upregulation in the P2Y(2) 42 kDa protein band expression after 4 days post-injury that continues until 28 days post-injury. However, a downregulation of the 62 kDa receptor protein band after 2 days post-injury that continues up to 28 days post-injury was observed. Therefore, the spatio-temporal pattern of P2Y(2) gene expression after spinal cord injury suggests a role in the pathophysiology response generated after trauma.
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Affiliation(s)
- Ana E Rodríguez-Zayas
- Department of Physiology, University of Puerto Rico, San Juan, PR 00936-5067, Puerto Rico
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43
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Boucher I, Rich C, Lee A, Marcincin M, Trinkaus-Randall V. The P2Y2 receptor mediates the epithelial injury response and cell migration. Am J Physiol Cell Physiol 2010; 299:C411-21. [PMID: 20427708 DOI: 10.1152/ajpcell.00100.2009] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Injury to epithelial cells results in the release of ATP and stimulation of purinergic receptors and is thought to alter cell migration and wound repair. Medium from the injured cells triggers Ca(2+) mobilization and phosphorylation of ERK, both of which are inhibited if the medium is pretreated with apyrase. To understand the wound repair mechanism that occurs with injury, our goal was to determine which purinergic receptor(s) was the critical player in the wound response. We hypothesize that the P2Y(2) receptor is the key player in the response of corneal epithelial cells to cell damage and subsequent repair events. Cells transfected with short interfering RNA to either P2Y(2) or P2Y(4) were stimulated either by injury or addition of UTP and imaged using fluo 3-AM to monitor changes in fluorescence. When cells with downregulated P2Y(2) receptors were injured or stimulated with UTP, the intensity of the Ca(2+) release was reduced significantly. However, when cells with downregulated P2Y(4) receptors were stimulated, only the UTP-induced Ca(2+) response was reduced significantly. In addition, downregulation of the P2Y(2) receptor inhibited wound closure compared with unstimulated cells or cells transfected with nontargeting sequence. This downregulation resulted also in an attenuation in phosphorylation of Src and ERK. Together, these data indicate that the P2Y(2) receptor plays a major biological role in the corneal injury response and repair mechanisms.
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Affiliation(s)
- Ilene Boucher
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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O'Keeffe MG, Thorne PR, Housley GD, Robson SC, Vlajkovic SM. Developmentally regulated expression of ectonucleotidases NTPDase5 and NTPDase6 and UDP-responsive P2Y receptors in the rat cochlea. Histochem Cell Biol 2010; 133:425-36. [PMID: 20217113 DOI: 10.1007/s00418-010-0682-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2010] [Indexed: 12/31/2022]
Abstract
Ectonucleoside triphosphate diphosphohydrolases (E-NTPDases) regulate complex extracellular P2 receptor signalling pathways in mammalian tissues by hydrolysing extracellular nucleotides to the respective nucleosides. All enzymes from this family (NTPDase1-8) are expressed in the adult rat cochlea. This study reports the changes in expression of NTPDase5 and NTPDase6 in the developing rat cochlea. These two intracellular members of the E-NTPDase family can be released in a soluble form and show preference for nucleoside 5'-diphosphates, such as UDP and GDP. Here, we demonstrate differential spatial and temporal patterns for NTPDase5 and NTPDase6 expression during cochlear development, which are indicative of both cytosolic and extracellular action via pyrimidines. NTPDase5 is noted during the early postnatal period in developing sensory hair cells and supporting Deiters' cells of the organ of Corti, and primary auditory neurons located in the spiral ganglion. In contrast, NTPDase6 is confined to the embryonic and early postnatal hair cell bundles. NTPDase6 immunolocalisation in the developing cochlea underpins its putative role in hair cell bundle development, probably via cytosolic action, whilst NTPDase5 may have a broader extracellular role in the development of sensory and neural tissues in the rat cochlea. Both NTPDase5 and NTPDase6 colocalize with UDP-preferring P2Y(4), P2Y(6) and P2Y(14) receptors during cochlear development, but this strong association was lost in the adult cochlea. Spatiotemporal topographic expression of NTPDase5 and NTPDase6 and P2Y receptors in adult and developing cochlear tissues provide strong support for the role of pyrimidinergic signalling in cochlear development.
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Affiliation(s)
- Mary G O'Keeffe
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand
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45
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ATP modulates transcription factors through P2Y2 and P2Y4 receptors via PKC/MAPKs and PKC/Src pathways in MCF-7 cells. Arch Biochem Biophys 2009; 494:7-14. [PMID: 19900397 DOI: 10.1016/j.abb.2009.11.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2009] [Revised: 11/03/2009] [Accepted: 11/04/2009] [Indexed: 02/04/2023]
Abstract
In this work, we studied the involvement of PKC and Src in the phosphorylation of ERK1/2, p38 and JNK1 MAPKs and in the modulation of ATF-1, c-Fos, c-Jun and Jun D transcription factors by ATP in MCF-7 breast cancer cells. RT-PCR studies and nucleotide sequence analysis confirmed first the expression of P2Y(2)- and P2Y(4)-receptor subtypes. The use of specific inhibitors and Src antisense oligonucleotides showed that PKC, but not Src, plays a role in the phosphorylation of MAPKs by ATP. ATP stimulated the expression of c-Fos and the phosphorylation c-Jun, Jun D and ATF-1. PKC and Src only participated in c-Fos induction and in ATF-1 phosphorylation. Pharmacological inhibition of MAPKs demonstrated that c-Fos induction and phosphorylation of c-Jun and Jun D, but not of ATF-1, depend on MAPK activation. These results suggest that stimulation of P2Y(2) and P2Y(4) receptors by ATP modulates transcription factors through PKC/MAPKs and PKC/Src pathways in MCF-7 cells.
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46
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Astrocytes in the damaged brain: molecular and cellular insights into their reactive response and healing potential. Biochem Pharmacol 2009; 79:77-89. [PMID: 19765548 DOI: 10.1016/j.bcp.2009.09.014] [Citation(s) in RCA: 238] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 09/08/2009] [Accepted: 09/10/2009] [Indexed: 12/29/2022]
Abstract
Long considered merely a trophic and mechanical support to neurons, astrocytes have progressively taken the center stage as their ability to react to acute and chronic neurodegenerative situations became increasingly clear. Reactive astrogliosis starts when trigger molecules produced at the injury site drive astrocytes to leave their quiescent state and become activated. Distinctive morphological and biochemical features characterize this process (cell hypertrophy, upregulation of intermediate filaments, and increased cell proliferation). Moreover, reactive astrocytes migrate towards the injured area to constitute the glial scar, and release factors mediating the tissue inflammatory response and remodeling after lesion. A novel view of astrogliosis derives from the finding that subsets of reactive astrocytes can recapitulate stem cell/progenitor features after damage, fostering the concept of astroglia as a promising target for reparative therapies. But which biochemical/signaling pathways modulate astrogliosis with respect to both the time after injury and the type of damage? Are reactive astrocytes overall beneficial or detrimental for neuroprotection and tissue regeneration? This debate has been animating this research field for several years now, and an integrated view on the results obtained and the possible future perspectives is needed. With this Commentary article we have attempted to answer the above-mentioned questions by reviewing the current knowledge on the molecular mechanisms controlling and sustaining the reaction of astroglia to injury and its stem cell-like properties. Moreover, the cellular/molecular mechanisms supporting the detrimental or beneficial features of astrogliosis have been scrutinized to gain insights on possible pharmacological approaches to enhance astrocyte neuroprotective activities.
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47
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Franke H, Sauer C, Rudolph C, Krügel U, Hengstler JG, Illes P. P2 receptor-mediated stimulation of the PI3-K/Akt-pathway in vivo. Glia 2009; 57:1031-45. [PMID: 19115395 DOI: 10.1002/glia.20827] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
ATP acts as a growth factor as well as a toxic agent by stimulating P2 receptors. The P2 receptor-activated signaling cascades mediating cellular growth and cell survival after injury are only incompletely understood. Therefore, the aim of the present study was to identify the role of the phosphoinositide 3 kinase (PI3-K/Akt) and the mitogen-activated protein kinase/extracellular signal regulated protein kinase (MAPK/ERK) pathways in P2Y receptor-mediated astrogliosis after traumatic injury and after microinfusion of ADP beta S (P2Y(1,12,13) receptor agonist) into the rat nucleus accumbens (NAc). Mechanical damage and even more the concomitant treatment with ADP beta S, enhanced P2Y(1) receptor-expression in the NAc, which could be reduced by pretreatment with the P2X/Y receptor antagonist PPADS. Quantitative Western blot analysis indicated a significant increase in phosphorylated (p)Akt and pERK1/2 2 h after ADP beta S-microinjection. Pretreatment with PPADS or wortmannin abolished the up-regulation of pAkt by injury alone or ADP beta S-treatment. The ADP beta S-enhanced expression of the early apoptosis marker active caspase 3 was reduced by PPADS and PD98059, but not by wortmannin. Multiple immunofluorescence labeling indicated a time-dependent expression of pAkt and pMAPK on astrocytes and neurons and additionally the colocalization of pAkt, pMAPK, and active caspase 3 with the P2Y(1) receptor especially at astrocytes. In conclusion, the data show for the first time the involvement of PI3-K/Akt-pathway in processes of injury-induced astroglial proliferation and anti-apoptosis via activation of P2Y(1) receptors in vivo, suggesting specific roles of P2 receptors in glial cell pathophysiology in neurodegenerative diseases.
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Affiliation(s)
- H Franke
- Rudolf-Boehm-Institute of Pharmacology and Toxicology, University of Leipzig, Leipzig, Germany.
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48
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Grimm I, Messemer N, Stanke M, Gachet C, Zimmermann H. Coordinate pathways for nucleotide and EGF signaling in cultured adult neural progenitor cells. J Cell Sci 2009; 122:2524-33. [PMID: 19549686 DOI: 10.1242/jcs.044891] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The adult subventricular zone (SVZ) contains astrocyte-like stem cells capable of generating new neurons for the olfactory bulb. Adult neurogenesis is driven by a variety of signal systems that can induce synergistic or opposing cellular responses. It is therefore important to gain insight into the underlying downstream signaling pathways. We have previously shown that the nucleotides ADPbetaS and UTP induce rapid Ca2+ transients in cultured SVZ-derived adult neural progenitors and augment growth-factor-mediated progenitor cell proliferation. Here, we investigated signaling pathways elicited by ADPbetaS, UTP and epidermal growth factor (EGF). All three agonists elicit ERK1/2 and CREB phosphorylation but the temporal characteristics differ between the nucleotides and EGF. Differentiation of the progenitors alters the receptor profile. Oligodendrocytes and young neurons, but not astrocytes, lose responsiveness to the agonists. Inhibition experiments are indicative of an ADPbetaS-elicited EGF receptor transactivation. Whereas UTP acts via the P2Y2 receptor, ADPbetaS exerts its function via the P2Y1 receptor and the P2Y13 receptor. Our data demonstrate that nucleotides and EGF induce converging, but also differential, intracellular signaling pathways and suggest that they carry the potential to act synergistically in the control of cell proliferation and cell survival in adult neurogenesis.
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Affiliation(s)
- Ivette Grimm
- Institute of Cell Biology and Neuroscience, Biocenter, J. W. Goethe-University, 60438 Frankfurt, Germany
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49
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Miller WJ, Leventhal I, Scarsella D, Haydon PG, Janmey P, Meaney DF. Mechanically Induced Reactive Gliosis Causes ATP-Mediated Alterations in Astrocyte Stiffness. J Neurotrauma 2009. [DOI: 10.1089/neu.2008.0727] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- William J. Miller
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ilya Leventhal
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David Scarsella
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Philip G. Haydon
- Department of Neuroscience, Tufts University, Boston, Massachusetts
| | - Paul Janmey
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute of Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David F. Meaney
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, Pennsylvania
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50
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Verkhrasky A, Krishtal OA, Burnstock G. Purinoceptors on Neuroglia. Mol Neurobiol 2009; 39:190-208. [DOI: 10.1007/s12035-009-8063-2] [Citation(s) in RCA: 154] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2009] [Accepted: 02/24/2009] [Indexed: 02/06/2023]
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