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Hladky SB, Barrand MA. Alterations in brain fluid physiology during the early stages of development of ischaemic oedema. Fluids Barriers CNS 2024; 21:51. [PMID: 38858667 PMCID: PMC11163777 DOI: 10.1186/s12987-024-00534-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 03/22/2024] [Indexed: 06/12/2024] Open
Abstract
Oedema occurs when higher than normal amounts of solutes and water accumulate in tissues. In brain parenchymal tissue, vasogenic oedema arises from changes in blood-brain barrier permeability, e.g. in peritumoral oedema. Cytotoxic oedema arises from excess accumulation of solutes within cells, e.g. ischaemic oedema following stroke. This type of oedema is initiated when blood flow in the affected core region falls sufficiently to deprive brain cells of the ATP needed to maintain ion gradients. As a consequence, there is: depolarization of neurons; neural uptake of Na+ and Cl- and loss of K+; neuronal swelling; astrocytic uptake of Na+, K+ and anions; swelling of astrocytes; and reduction in ISF volume by fluid uptake into neurons and astrocytes. There is increased parenchymal solute content due to metabolic osmolyte production and solute influx from CSF and blood. The greatly increased [K+]isf triggers spreading depolarizations into the surrounding penumbra increasing metabolic load leading to increased size of the ischaemic core. Water enters the parenchyma primarily from blood, some passing into astrocyte endfeet via AQP4. In the medium term, e.g. after three hours, NaCl permeability and swelling rate increase with partial opening of tight junctions between blood-brain barrier endothelial cells and opening of SUR1-TPRM4 channels. Swelling is then driven by a Donnan-like effect. Longer term, there is gross failure of the blood-brain barrier. Oedema resolution is slower than its formation. Fluids without colloid, e.g. infused mock CSF, can be reabsorbed across the blood-brain barrier by a Starling-like mechanism whereas infused serum with its colloids must be removed by even slower extravascular means. Large scale oedema can increase intracranial pressure (ICP) sufficiently to cause fatal brain herniation. The potentially lethal increase in ICP can be avoided by craniectomy or by aspiration of the osmotically active infarcted region. However, the only satisfactory treatment resulting in retention of function is restoration of blood flow, providing this can be achieved relatively quickly. One important objective of current research is to find treatments that increase the time during which reperfusion is successful. Questions still to be resolved are discussed.
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Affiliation(s)
- Stephen B Hladky
- Department of Pharmacology, Tennis Court Rd., Cambridge, CB2 1PD, UK.
| | - Margery A Barrand
- Department of Pharmacology, Tennis Court Rd., Cambridge, CB2 1PD, UK
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Dhapola R, Medhi B, HariKrishnaReddy D. Insight into the pathophysiological advances and molecular mechanisms underlying cerebral stroke: current status. Mol Biol Rep 2024; 51:649. [PMID: 38733445 DOI: 10.1007/s11033-024-09597-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Accepted: 04/30/2024] [Indexed: 05/13/2024]
Abstract
Molecular pathways involved in cerebral stroke are diverse. The major pathophysiological events that are observed in stroke comprises of excitotoxicity, oxidative stress, mitochondrial damage, endoplasmic reticulum stress, cellular acidosis, blood-brain barrier disruption, neuronal swelling and neuronal network mutilation. Various biomolecules are involved in these pathways and several major proteins are upregulated and/or suppressed following stroke. Different types of receptors, ion channels and transporters are activated. Fluctuations in levels of various ions and neurotransmitters have been observed. Cells involved in immune responses and various mediators involved in neuro-inflammation get upregulated progressing the pathogenesis of the disease. Despite of enormity of the problem, there is not a single therapy that can limit infarction and neurological disability due to stroke. This is because of poor understanding of the complex interplay between these pathophysiological processes. This review focuses upon the past to present research on pathophysiological events that are involved in stroke and various factors that are leading to neuronal death following cerebral stroke. This will pave a way to researchers for developing new potent therapeutics that can aid in the treatment of cerebral stroke.
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Affiliation(s)
- Rishika Dhapola
- Advanced Pharmacology and Neuroscience Laboratory, Department of Pharmacology, School of Health Sciences, Central University of Punjab, Ghudda, Bathinda, Punjab, 151401, India
| | - Bikash Medhi
- Department of Pharmacology, Post Graduate Institute of Medical Education and Research, Chandigarh, Punjab, 160012, India
| | - Dibbanti HariKrishnaReddy
- Advanced Pharmacology and Neuroscience Laboratory, Department of Pharmacology, School of Health Sciences, Central University of Punjab, Ghudda, Bathinda, Punjab, 151401, India.
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Tregub PP, Kulikov VP, Ibrahimli I, Tregub OF, Volodkin AV, Ignatyuk MA, Kostin AA, Atiakshin DA. Molecular Mechanisms of Neuroprotection after the Intermittent Exposures of Hypercapnic Hypoxia. Int J Mol Sci 2024; 25:3665. [PMID: 38612476 PMCID: PMC11011936 DOI: 10.3390/ijms25073665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 03/19/2024] [Accepted: 03/21/2024] [Indexed: 04/14/2024] Open
Abstract
The review introduces the stages of formation and experimental confirmation of the hypothesis regarding the mutual potentiation of neuroprotective effects of hypoxia and hypercapnia during their combined influence (hypercapnic hypoxia). The main focus is on the mechanisms and signaling pathways involved in the formation of ischemic tolerance in the brain during intermittent hypercapnic hypoxia. Importantly, the combined effect of hypoxia and hypercapnia exerts a more pronounced neuroprotective effect compared to their separate application. Some signaling systems are associated with the predominance of the hypoxic stimulus (HIF-1α, A1 receptors), while others (NF-κB, antioxidant activity, inhibition of apoptosis, maintenance of selective blood-brain barrier permeability) are mainly modulated by hypercapnia. Most of the molecular and cellular mechanisms involved in the formation of brain tolerance to ischemia are due to the contribution of both excess carbon dioxide and oxygen deficiency (ATP-dependent potassium channels, chaperones, endoplasmic reticulum stress, mitochondrial metabolism reprogramming). Overall, experimental studies indicate the dominance of hypercapnia in the neuroprotective effect of its combined action with hypoxia. Recent clinical studies have demonstrated the effectiveness of hypercapnic-hypoxic training in the treatment of childhood cerebral palsy and diabetic polyneuropathy in children. Combining hypercapnic hypoxia with pharmacological modulators of neuro/cardio/cytoprotection signaling pathways is likely to be promising for translating experimental research into clinical medicine.
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Affiliation(s)
- Pavel P. Tregub
- Department of Pathophysiology, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia;
- Brain Science Institute, Research Center of Neurology, 125367 Moscow, Russia
- Scientific and Educational Resource Center “Innovative Technologies of Immunophenotyping, Digital Spatial Profiling and Ultrastructural Analysis”, RUDN University, 117198 Moscow, Russia; (A.V.V.); (M.A.I.); (A.A.K.); (D.A.A.)
| | - Vladimir P. Kulikov
- Department of Ultrasound and Functional Diagnostics, Altay State Medical University, 656040 Barnaul, Russia;
| | - Irada Ibrahimli
- Department of Pathophysiology, I.M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia;
| | | | - Artem V. Volodkin
- Scientific and Educational Resource Center “Innovative Technologies of Immunophenotyping, Digital Spatial Profiling and Ultrastructural Analysis”, RUDN University, 117198 Moscow, Russia; (A.V.V.); (M.A.I.); (A.A.K.); (D.A.A.)
| | - Michael A. Ignatyuk
- Scientific and Educational Resource Center “Innovative Technologies of Immunophenotyping, Digital Spatial Profiling and Ultrastructural Analysis”, RUDN University, 117198 Moscow, Russia; (A.V.V.); (M.A.I.); (A.A.K.); (D.A.A.)
| | - Andrey A. Kostin
- Scientific and Educational Resource Center “Innovative Technologies of Immunophenotyping, Digital Spatial Profiling and Ultrastructural Analysis”, RUDN University, 117198 Moscow, Russia; (A.V.V.); (M.A.I.); (A.A.K.); (D.A.A.)
| | - Dmitrii A. Atiakshin
- Scientific and Educational Resource Center “Innovative Technologies of Immunophenotyping, Digital Spatial Profiling and Ultrastructural Analysis”, RUDN University, 117198 Moscow, Russia; (A.V.V.); (M.A.I.); (A.A.K.); (D.A.A.)
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Liao S, Wu G, Xie Z, Lei X, Yang X, Huang S, Deng X, Wang Z, Tang G. pH regulators and their inhibitors in tumor microenvironment. Eur J Med Chem 2024; 267:116170. [PMID: 38308950 DOI: 10.1016/j.ejmech.2024.116170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 01/14/2024] [Accepted: 01/22/2024] [Indexed: 02/05/2024]
Abstract
As an important characteristic of tumor, acidic tumor microenvironment (TME) is closely related to immune escape, invasion, migration and drug resistance of tumor. The acidity of the TME mainly comes from the acidic products produced by the high level of tumor metabolism, such as lactic acid and carbon dioxide. pH regulators such as monocarboxylate transporters (MCTs), carbonic anhydrase IX (CA IX), and Na+/H+ exchange 1 (NHE1) expel protons directly or indirectly from the tumor to maintain the pH balance of tumor cells and create an acidic TME. We review the functions of several pH regulators involved in the construction of acidic TME, the structure and structure-activity relationship of pH regulator inhibitors, and provide strategies for the development of small-molecule antitumor inhibitors based on these targets.
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Affiliation(s)
- Senyi Liao
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Guang Wu
- The Second Affiliated Hospital, Department of Pharmacy, Hengyang Medical School, University of South China, Hengyang, 421001, Hunan, China
| | - Zhizhong Xie
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Xiaoyong Lei
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Xiaoyan Yang
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China
| | - Sheng Huang
- Jiuzhitang Co., Ltd, Changsha, Hunan, 410007, China
| | - Xiangping Deng
- The First Affiliated Hospital, Department of Pharmacy, Hengyang Medical School, University of South China, Hengyang, 421001, Hunan, China.
| | - Zhe Wang
- The Second Affiliated Hospital, Department of Pharmacy, Hengyang Medical School, University of South China, Hengyang, 421001, Hunan, China.
| | - Guotao Tang
- Institute of Pharmacy and Pharmacology, Hunan Provincial Key Laboratory of Tumor Microenvironment Responsive Drug Research, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, China.
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Aboouf MA, Gorr TA, Hamdy NM, Gassmann M, Thiersch M. Myoglobin in Brown Adipose Tissue: A Multifaceted Player in Thermogenesis. Cells 2023; 12:2240. [PMID: 37759463 PMCID: PMC10526770 DOI: 10.3390/cells12182240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/01/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
Brown adipose tissue (BAT) plays an important role in energy homeostasis by generating heat from chemical energy via uncoupled oxidative phosphorylation. Besides its high mitochondrial content and its exclusive expression of the uncoupling protein 1, another key feature of BAT is the high expression of myoglobin (MB), a heme-containing protein that typically binds oxygen, thereby facilitating the diffusion of the gas from cell membranes to mitochondria of muscle cells. In addition, MB also modulates nitric oxide (NO•) pools and can bind C16 and C18 fatty acids, which indicates a role in lipid metabolism. Recent studies in humans and mice implicated MB present in BAT in the regulation of lipid droplet morphology and fatty acid shuttling and composition, as well as mitochondrial oxidative metabolism. These functions suggest that MB plays an essential role in BAT energy metabolism and thermogenesis. In this review, we will discuss in detail the possible physiological roles played by MB in BAT thermogenesis along with the potential underlying molecular mechanisms and focus on the question of how BAT-MB expression is regulated and, in turn, how this globin regulates mitochondrial, lipid, and NO• metabolism. Finally, we present potential MB-mediated approaches to augment energy metabolism, which ultimately could help tackle different metabolic disorders.
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Affiliation(s)
- Mostafa A. Aboouf
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo 11566, Egypt
| | - Thomas A. Gorr
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
| | - Nadia M. Hamdy
- Department of Biochemistry, Faculty of Pharmacy, Ain Shams University, Cairo 11566, Egypt
| | - Max Gassmann
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Markus Thiersch
- Institute of Veterinary Physiology, University of Zurich, 8057 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
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Upregulation of MiRNA-149-5p Reduces the Infract Volume in Middle Cerebral Artery Occlusion Rats by Modulating Cation-Chloride Cotransporters Expressions. IRANIAN BIOMEDICAL JOURNAL 2022; 26:357-65. [PMID: 35871268 PMCID: PMC9763874 DOI: 10.52547/ibj.3759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Background Brain ischemia often leads to the chloride gradient alternations, which affects volume regulation and neuronal survival. Increase in NKCC1 expression and reduction in KCC2 level under ischemic condition results in inflammation and neuronal death. In this study, we investigated the effect of mimic miRNA and coenzyme Q10 (CoQ10) on the expression of cation-chloride cotransporters (CCCs) (NKCC1 and KCC2) after cerebral ischemia. Methods In this study, cerebral ischemia was modeled using the middle cerebral artery occlusion method. Rats were randomly divided into six groups: sham, model, negative control, vehicle, and the first and second treatments. In the Sham group, ischemia was not induced, and no treatment was performed. In the Model group, ischemia induction was performed, and other groups, in addition to ischemia induction, received Scramble miRNA, Ethanol, mimic miRNA-149-5p and CoQ10, respectively. Each group was divided into three subgroups to assess the volume of the tissue damage and neurological deficits scores (NDS) in subgroup 1, brain water content in subgroup 2, level of miRNA-149-5p and CCC expressions in subgroup 3. Results Our data suggested that the use of mimic miRNA and Q10 increased the level of miRNA-149 and KCC2 expression and decreased NDS, NKCC1 expression, brain water content, and infract volume. Conclusion Findings of this study suggest that the mimic miRNA and Q10 may have neuroprotective effects through reducing infract volume and brain water content and modulating the expression of CCCs after brain ischemia.
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Ochoa-de la Paz LD, Gulias-Cañizo R. Glia as a key factor in cell volume regulation processes of the central nervous system. Front Cell Neurosci 2022; 16:967496. [PMID: 36090789 PMCID: PMC9453262 DOI: 10.3389/fncel.2022.967496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 08/03/2022] [Indexed: 11/23/2022] Open
Abstract
Brain edema is a pathological condition with potentially fatal consequences, related to cerebral injuries such as ischemia, chronic renal failure, uremia, and diabetes, among others. Under these pathological states, the cell volume control processes are fully compromised, because brain cells are unable to regulate the movement of water, mainly regulated by osmotic gradients. The processes involved in cell volume regulation are homeostatic mechanisms that depend on the mobilization of osmolytes (ions, organic molecules, and polyols) in the necessary direction to counteract changes in osmolyte concentration in response to water movement. The expression and coordinated function of proteins related to the cell volume regulation process, such as water channels, ion channels, and other cotransport systems in the glial cells, and considering the glial cell proportion compared to neuronal cells, leads to consider the astroglial network the main regulatory unit for water homeostasis in the central nervous system (CNS). In the last decade, several studies highlighted the pivotal role of glia in the cell volume regulation process and water homeostasis in the brain, including the retina; any malfunction of this astroglial network generates a lack of the ability to regulate the osmotic changes and water movements and consequently exacerbates the pathological condition.
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Affiliation(s)
- Lenin David Ochoa-de la Paz
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico
- Asociación para Evitar la Ceguera en México (APEC), Unidad de Investigación APEC-UNAM, Mexico
- *Correspondence: Lenin David Ochoa-de la Paz
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Ji MJ, Ryu HJ, Hong JH. Synovial Fluid of Patient With Rheumatoid Arthritis Enhanced Osmotic Sensitivity Through the Cytotoxic Edema Module in Synoviocytes. Front Cell Dev Biol 2021; 9:700879. [PMID: 34532317 PMCID: PMC8438158 DOI: 10.3389/fcell.2021.700879] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/28/2021] [Indexed: 12/12/2022] Open
Abstract
Rheumatoid arthritis (RA) is an autoimmune disease that causes inflammation of the synovial membrane ultimately leading to permanent damage in the affected joints. For this study, synovial fluids from 16 patients diagnosed with either RA or osteoarthritis (OA) were used to examine volume regulation and cooperative water channels, both of which are involved in the cytotoxic edema identified in RA-fibroblast-like synoviocytes (FLS). The osmolarity and inflammatory cytokine interleukin (IL)-6 of synovial fluids from RA patients were mildly enhanced compared to that from OA patients. RA-FLS demonstrated the enhanced property of regulatory volume increase in response to IL-6 and synovial fluids from RA patients. Although there was no difference in the protein expression of the volume-associated protein sodium–potassium–chloride cotransporter1 (NKCC1), its activity was increased by treatment with IL-6. Membrane localization of NKCC1 was also increased by IL-6 treatment. Additionally, both the protein and membrane expressions of aquaporin-1 were increased in RA-FLS by IL-6 stimulation. The IL-6-mediated enhanced osmotic sensitivity of RA-FLS likely involves NKCC1 and aquaporin-1, which mainly constitute the volume-associated ion transporter and water channel elements. These results suggest that RA-FLS provide enhanced electrolytes and concomitant water movement through NKCC1 and aquaporin-1, thereby inducing cellular swelling ultimately resulting in cytotoxic edema. Attenuation of cytotoxic edema and verification of its related mechanism will provide novel therapeutic approaches to RA treatment within the scope of cytotoxic edema.
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Affiliation(s)
- Min Jeong Ji
- Department of Physiology, College of Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, South Korea.,Department of Oral Biology, Yonsei University College of Dentistry, Seoul, South Korea
| | - Hee Jung Ryu
- Division of Rheumatology, Department of Internal Medicine, Gachon University College of Medicine Gil Medical Center, Incheon, South Korea
| | - Jeong Hee Hong
- Department of Physiology, College of Medicine, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, South Korea
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Luo X, Yang S, Luo Y, Qiu H, Li T, Li J, Chen X, Zheng X, Chen Y, Zhang J, Zhang Z, Qin C. Molecular Characterization and Expression Analysis of the Na +/H + Exchanger Gene Family in Capsicum annuum L. Front Genet 2021; 12:680457. [PMID: 34539731 PMCID: PMC8444994 DOI: 10.3389/fgene.2021.680457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 08/02/2021] [Indexed: 11/13/2022] Open
Abstract
The Na+/H+ exchangers (NHXs) are a class of transporters involved in ion balance during plant growth and abiotic stress. We performed systematic bioinformatic identification and expression-characteristic analysis of CaNHX genes in pepper to provide a theoretical basis for pepper breeding and practical production. At the whole-genome level, the members of the CaNHX gene family of cultivated and wild pepper were systematically identified using bioinformatics methods. Sequence alignment and phylogenetic tree construction were performed using MEGA X software, and the gene functional domain, conserved motif, and gene structure were analyzed and visualized. At the same time, the co-expression network of CaNHX genes was analyzed, and salt-stress analysis and fluorescence quantitative verification of the Zunla-1 cultivar under stress conditions were performed. A total of 9 CaNHX genes were identified, which have typical functional domains of the Na+/H+ exchanger gene. The physical and chemical properties of the protein showed that the protein was hydrophilic, with a size of 503-1146 amino acids. Analysis of the gene structure showed that Chr08 was the most localized chromosome, with 8-24 exons. Cis-acting element analysis showed that it mainly contains cis-acting elements such as light response, salicylic acid response, defense, and stress response. Transcriptom and co-expression network analysis showed that under stress, the co-expressed genes of CaNHX genes in roots and leaves were more obvious than those in the control group, including ABA, IAA, and salt. The transcriptome and co-expression were verified by qRT-PCR. In this study, the CaNHX genes were identified at the genome level of pepper, which provides a theoretical foundation for improving the stress resistance, production, development, and utilization of pepper in genetic breeding.
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Affiliation(s)
- Xirong Luo
- Department of Modern Agriculture, Zunyi Vocational and Technical College, Zunyi, China
- Key Lab of Zunyi Crop Gene Resource and Germplasm Innovation, Zunyi Academy of Agricultural Sciences, Zunyi, China
| | - Shimei Yang
- Department of Modern Agriculture, Zunyi Vocational and Technical College, Zunyi, China
| | - Yong Luo
- Key Lab of Zunyi Crop Gene Resource and Germplasm Innovation, Zunyi Academy of Agricultural Sciences, Zunyi, China
| | - Huarong Qiu
- Key Lab of Zunyi Crop Gene Resource and Germplasm Innovation, Zunyi Academy of Agricultural Sciences, Zunyi, China
| | - Tangyan Li
- Department of Modern Agriculture, Zunyi Vocational and Technical College, Zunyi, China
- Yunnan Provincial Key Lab of Agricultural Biotechnology, Key Lab of Southwestern Crop Gene Resources and Germplasm Innovation, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Ministry of Agriculture, Kunming, China
| | - Jing Li
- Department of Modern Agriculture, Zunyi Vocational and Technical College, Zunyi, China
| | - Xiaocui Chen
- Key Lab of Zunyi Crop Gene Resource and Germplasm Innovation, Zunyi Academy of Agricultural Sciences, Zunyi, China
| | - Xue Zheng
- Yunnan Provincial Key Lab of Agricultural Biotechnology, Key Lab of Southwestern Crop Gene Resources and Germplasm Innovation, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Ministry of Agriculture, Kunming, China
| | - Yongdui Chen
- Yunnan Provincial Key Lab of Agricultural Biotechnology, Key Lab of Southwestern Crop Gene Resources and Germplasm Innovation, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Ministry of Agriculture, Kunming, China
| | - Jie Zhang
- Yunnan Provincial Key Lab of Agricultural Biotechnology, Key Lab of Southwestern Crop Gene Resources and Germplasm Innovation, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Ministry of Agriculture, Kunming, China
| | - Zhongkai Zhang
- Yunnan Provincial Key Lab of Agricultural Biotechnology, Key Lab of Southwestern Crop Gene Resources and Germplasm Innovation, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Ministry of Agriculture, Kunming, China
| | - Cheng Qin
- Department of Modern Agriculture, Zunyi Vocational and Technical College, Zunyi, China
- Yunnan Provincial Key Lab of Agricultural Biotechnology, Key Lab of Southwestern Crop Gene Resources and Germplasm Innovation, Biotechnology and Germplasm Resources Institute, Yunnan Academy of Agricultural Sciences, Ministry of Agriculture, Kunming, China
- School of Agriculture, Yunnan University, Kunming, China
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Blackburn ML, Wankhade UD, Ono-Moore KD, Chintapalli SV, Fox R, Rutkowsky JM, Willis BJ, Tolentino T, Lloyd KCK, Adams SH. On the potential role of globins in brown adipose tissue: a novel conceptual model and studies in myoglobin knockout mice. Am J Physiol Endocrinol Metab 2021; 321:E47-E62. [PMID: 33969705 PMCID: PMC8321818 DOI: 10.1152/ajpendo.00662.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Myoglobin (Mb) regulates O2 bioavailability in muscle and heart as the partial pressure of O2 (Po2) drops with increased tissue workload. Globin proteins also modulate cellular NO pools, "scavenging" NO at higher Po2 and converting NO2- to NO as Po2 falls. Myoglobin binding of fatty acids may also signal a role in fat metabolism. Interestingly, Mb is expressed in brown adipose tissue (BAT), but its function is unknown. Herein, we present a new conceptual model that proposes links between BAT thermogenic activation, concurrently reduced Po2, and NO pools regulated by deoxy/oxy-globin toggling and xanthine oxidoreductase (XOR). We describe the effect of Mb knockout (Mb-/-) on BAT phenotype [lipid droplets, mitochondrial markers uncoupling protein 1 (UCP1) and cytochrome C oxidase 4 (Cox4), transcriptomics] in male and female mice fed a high-fat diet (HFD, 45% of energy, ∼13 wk), and examine Mb expression during brown adipocyte differentiation. Interscapular BAT weights did not differ by genotype, but there was a higher prevalence of mid-large sized droplets in Mb-/-. COX4 protein expression was significantly reduced in Mb-/- BAT, and a suite of metabolic/NO/stress/hypoxia transcripts were lower. All of these Mb-/--associated differences were most apparent in females. The new conceptual model, and results derived from Mb-/- mice, suggest a role for Mb in BAT metabolic regulation, in part through sexually dimorphic systems and NO signaling. This possibility requires further validation in light of significant mouse-to-mouse variability of BAT Mb mRNA and protein abundances in wild-type mice and lower expression relative to muscle and heart.NEW & NOTEWORTHY Myoglobin confers the distinct red color to muscle and heart, serving as an oxygen-binding protein in oxidative fibers. Less attention has been paid to brown fat, a thermogenic tissue that also expresses myoglobin. In a mouse knockout model lacking myoglobin, brown fat had larger fat droplets and lower markers of mitochondrial oxidative metabolism, especially in females. Gene expression patterns suggest a role for myoglobin as an oxygen/nitric oxide-sensor that regulates cellular metabolic and signaling pathways.
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Affiliation(s)
- Michael L Blackburn
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Umesh D Wankhade
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | | | - Sree V Chintapalli
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Renee Fox
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
| | - Jennifer M Rutkowsky
- Department of Molecular Biosciences, UC Davis School of Veterinary Medicine, University of California, Davis, California
- Mouse Metabolic Phenotyping Center, University of California, Davis, California
| | - Brandon J Willis
- Mouse Biology Program, University of California, Davis, California
| | - Todd Tolentino
- Mouse Metabolic Phenotyping Center, University of California, Davis, California
- Mouse Biology Program, University of California, Davis, California
| | - K C Kent Lloyd
- Mouse Metabolic Phenotyping Center, University of California, Davis, California
- Mouse Biology Program, University of California, Davis, California
- Department of Surgery, University of California Davis School of Medicine, Sacramento, California
| | - Sean H Adams
- Arkansas Children's Nutrition Center, Little Rock, Arkansas
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
- Department of Surgery, University of California Davis School of Medicine, Sacramento, California
- Center for Alimentary and Metabolic Science, University of California Davis School of Medicine, Sacramento, California
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Praetorius H. The bacteria and the host: a story of purinergic signaling in urinary tract infections. Am J Physiol Cell Physiol 2021; 321:C134-C146. [PMID: 33979212 DOI: 10.1152/ajpcell.00054.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The local environment forces a selection of bacteria that might invade the urinary tract, allowing only the most virulent to access the kidney. Quite similar to the diet in setting the stage for the gut microbiome, renal function determines the conditions for bacteria-host interaction in the urinary tract. In the kidney, the term local environment or microenvironment is completely justified because the environment literally changes within a few micrometers. The precise composition of the urine is a function of the epithelium lining the microdomain, and the microenvironment in the kidney shows more variation in the content of nutrients, ion composition, osmolality, and pH than any other site of bacteria-host interaction. This review will cover some of the aspects of bacterial-host interaction in this unique setting and how uropathogenic bacteria can alter the condition for bacteria-host interaction. There will be a particular focus on the recent findings regarding how bacteria specifically trigger host paracrine signaling, via release of extracellular ATP and activation of P2 purinergic receptors. These finding will be discussed from the perspective of severe urinary tract infections, including pyelonephritis and urosepsis.
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Hu Y, Lou J, Jin Z, Yang X, Shan W, Du Q, Liao Q, Xu J, Xie R. Advances in research on the regulatory mechanism of NHE1 in tumors. Oncol Lett 2021; 21:273. [PMID: 33717270 PMCID: PMC7885159 DOI: 10.3892/ol.2021.12534] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022] Open
Abstract
Tumors pose a major threat to human health and present with difficulties that modern medicine has yet to overcome. It has been demonstrated that the acid-base balance of the tumor microenvironment is closely associated with the dynamic balance in the human body and that it regulates several processes, such as cell proliferation and differentiation, intracellular enzyme activity, and cytoskeletal assembly and depolymerization. It has been well established that the regulation of intra- and extracellular pH depends on a series of functional ion transporters and hydrogen ion channels, such as the Na+/H+ exchanger (NHE) protein and thee Cl/HCO3- exchange protein, among which the NHE1 member of the NHE family has been attracting increasing attention in recent years, particularly in studies on the correlation between pH regulation and tumors. NHE1 is a housekeeping gene encoding a protein that is widely expressed on the surface of all plasma membranes. Due to its functional domain, which determines the pHi at its N-terminus and C-terminus, NHE1 is involved in the regulation of the cellular pH microenvironment. It has been reported in the literature that NHE1 can regulate cell volume, participate in the transmembrane transport of intracellular and extracellular ions, affect cell proliferation and apoptosis, and regulate cell behavior and cell cycle progression; however, research on the role of NHE1 in tumorigenesis and tumor development in various systems is at its early stages. The aim of the present study was to review the current research on the correlation between the NHE family proteins and various systemic tumors, in order to indicate a new direction for antitumor drug development with the pH microenvironment as the target.
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Affiliation(s)
- Yanxia Hu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Jun Lou
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Zhe Jin
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Xiaoxu Yang
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Weixi Shan
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Qian Du
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Qiushi Liao
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Jingyu Xu
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
| | - Rui Xie
- Department of Gastroenterology, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
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13
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Koltai T. Targeting the pH Paradigm at the Bedside: A Practical Approach. Int J Mol Sci 2020; 21:E9221. [PMID: 33287221 PMCID: PMC7730959 DOI: 10.3390/ijms21239221] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 11/27/2020] [Accepted: 11/28/2020] [Indexed: 02/07/2023] Open
Abstract
The inversion of the pH gradient in malignant tumors, known as the pH paradigm, is increasingly becoming accepted by the scientific community as a hallmark of cancer. Accumulated evidence shows that this is not simply a metabolic consequence of a dysregulated behavior, but rather an essential process in the physiopathology of accelerated proliferation and invasion. From the over-simplification of increased lactate production as the cause of the paradigm, as initially proposed, basic science researchers have arrived at highly complex and far-reaching knowledge, that substantially modified that initial belief. These new developments show that the paradigm entails a different regulation of membrane transporters, electrolyte exchangers, cellular and membrane enzymes, water trafficking, specialized membrane structures, transcription factors, and metabolic changes that go far beyond fermentative glycolysis. This complex world of dysregulations is still shuttered behind the walls of experimental laboratories and has not yet reached bedside medicine. However, there are many known pharmaceuticals and nutraceuticals that are capable of targeting the pH paradigm. Most of these products are well known, have low toxicity, and are also inexpensive. They need to be repurposed, and this would entail shorter clinical studies and enormous cost savings if we compare them with the time and expense required for the development of a new molecule. Will targeting the pH paradigm solve the "cancer problem"? Absolutely not. However, reversing the pH inversion would strongly enhance standard treatments, rendering them more efficient, and in some cases permitting lower doses of toxic drugs. This article's goal is to describe how to reverse the pH gradient inversion with existing drugs and nutraceuticals that can easily be used in bedside medicine, without adding toxicity to established treatments. It also aims at increasing awareness among practicing physicians that targeting the pH paradigm would be able to improve the results of standard therapies. Some clinical cases will be presented as well, showing how the pH gradient inversion can be treated at the bedside in a simple manner with repurposed drugs.
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Affiliation(s)
- Tomas Koltai
- Centro de Diagnostico y Tratamiento de la Obra Social del Personal de la Alimentacion, Talar de Pacheco, Buenos Aires 1617, Argentina
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14
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Pedersen SF, Counillon L. The SLC9A-C Mammalian Na +/H + Exchanger Family: Molecules, Mechanisms, and Physiology. Physiol Rev 2019; 99:2015-2113. [PMID: 31507243 DOI: 10.1152/physrev.00028.2018] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Na+/H+ exchangers play pivotal roles in the control of cell and tissue pH by mediating the electroneutral exchange of Na+ and H+ across cellular membranes. They belong to an ancient family of highly evolutionarily conserved proteins, and they play essential physiological roles in all phyla. In this review, we focus on the mammalian Na+/H+ exchangers (NHEs), the solute carrier (SLC) 9 family. This family of electroneutral transporters constitutes three branches: SLC9A, -B, and -C. Within these, each isoform exhibits distinct tissue expression profiles, regulation, and physiological roles. Some of these transporters are highly studied, with hundreds of original articles, and some are still only rudimentarily understood. In this review, we present and discuss the pioneering original work as well as the current state-of-the-art research on mammalian NHEs. We aim to provide the reader with a comprehensive view of core knowledge and recent insights into each family member, from gene organization over protein structure and regulation to physiological and pathophysiological roles. Particular attention is given to the integrated physiology of NHEs in the main organ systems. We provide several novel analyses and useful overviews, and we pinpoint main remaining enigmas, which we hope will inspire novel research on these highly versatile proteins.
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Affiliation(s)
- S F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
| | - L Counillon
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Copenhagen, Denmark; and Université Côte d'Azur, CNRS, Laboratoire de Physiomédecine Moléculaire, LP2M, France, and Laboratories of Excellence Ion Channel Science and Therapeutics, Nice, France
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15
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Yuen NY, Chechneva OV, Chen YJ, Tsai YC, Little LK, Dang J, Tancredi DJ, Conston J, Anderson SE, O'Donnell ME. Exacerbated brain edema in a rat streptozotocin model of hyperglycemic ischemic stroke: Evidence for involvement of blood-brain barrier Na-K-Cl cotransport and Na/H exchange. J Cereb Blood Flow Metab 2019; 39:1678-1692. [PMID: 29739261 PMCID: PMC6727129 DOI: 10.1177/0271678x18770844] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Cerebral edema is exacerbated in diabetic ischemic stroke through poorly understood mechanisms. We showed previously that blood-brain barrier (BBB) Na-K-Cl cotransport (NKCC) and Na/H exchange (NHE) are major contributors to edema formation in normoglycemic ischemic stroke. Here, we investigated whether hyperglycemia-exacerbated edema involves changes in BBB NKCC and NHE expression and/or activity and whether inhibition of NKCC or NHE effectively reduces edema and injury in a type I diabetic model of hyperglycemic stroke. Cerebral microvascular endothelial cell (CMEC) NKCC and NHE abundances and activities were determined by Western blot, radioisotopic flux and microspectrofluorometric methods. Cerebral edema and Na in rats subjected to middle cerebral artery occlusion (MCAO) were assessed by nuclear magnetic resonance methods. Hyperglycemia exposures of 1-7d significantly increased CMEC NKCC and NHE abundance and activity. Subsequent exposure to ischemic factors caused more robust increases in NKCC and NHE activities than in normoglycemic CMEC. MCAO-induced edema and brain Na uptake were greater in hyperglycemic rats. Intravenous bumetanide and HOE-642 significantly attenuated edema, brain Na uptake and ischemic injury. Our findings provide evidence that BBB NKCC and NHE contribute to increased edema in hyperglycemic stroke, suggesting that these Na transporters are promising therapeutic targets for reducing damage in diabetic stroke.
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Affiliation(s)
- Natalie Y Yuen
- 1 Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Olga V Chechneva
- 1 Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Yi-Je Chen
- 2 Department of Pharmacology, University of California, Davis, CA, USA
| | - Yi-Chen Tsai
- 1 Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Logan K Little
- 1 Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - James Dang
- 1 Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Daniel J Tancredi
- 3 Department of Pediatrics, University of California, Davis, CA, USA
| | - Jacob Conston
- 1 Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Steven E Anderson
- 1 Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
| | - Martha E O'Donnell
- 1 Department of Physiology and Membrane Biology, University of California, Davis, CA, USA
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16
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Toft-Bertelsen TL, Larsen BR, MacAulay N. Sensing and regulation of cell volume - we know so much and yet understand so little: TRPV4 as a sensor of volume changes but possibly without a volume-regulatory role? Channels (Austin) 2019; 12:100-108. [PMID: 29424275 PMCID: PMC5972811 DOI: 10.1080/19336950.2018.1438009] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cellular volume changes lead to initiation of cell volume regulatory events, the molecular identity of which remains unresolved. We here discuss experimental challenges associated with investigation of volume regulation during application of large, non-physiological osmotic gradients. The TRPV4 ion channel responds to volume increase irrespectively of the molecular mechanism underlying cell swelling, and is thus considered a sensor of volume changes. Evidence pointing towards the involvement of TRPV4 in subsequent volume regulatory mechanisms is intriguing, yet far from conclusive. We here present an experimental setting with astrocytic cell swelling in the absence of externally applied osmotic gradients, and the lack of evidence for involvement of TRPV4 in this regulatory volume response. Our aim with these new data and the preceding discussion is to stimulate further experimental effort in this area of research to clarify the role of TRPV4 and other channels and transporters in regulatory volume responses.
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Affiliation(s)
| | - Brian R Larsen
- a Department of Neuroscience , University of Copenhagen , Copenhagen , Denmark
| | - Nanna MacAulay
- a Department of Neuroscience , University of Copenhagen , Copenhagen , Denmark
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17
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Huang H, Song S, Banerjee S, Jiang T, Zhang J, Kahle KT, Sun D, Zhang Z. The WNK-SPAK/OSR1 Kinases and the Cation-Chloride Cotransporters as Therapeutic Targets for Neurological Diseases. Aging Dis 2019; 10:626-636. [PMID: 31165006 PMCID: PMC6538211 DOI: 10.14336/ad.2018.0928] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Accepted: 09/28/2018] [Indexed: 02/05/2023] Open
Abstract
In recent years, cation-chloride cotransporters (CCCs) have drawn attention in the medical neuroscience research. CCCs include the family of Na+-coupled Cl- importers (NCC, NKCC1, and NKCC2), K+-coupled Cl- exporters (KCCs), and possibly polyamine transporters (CCC9) and CCC interacting protein (CIP1). For decades, CCCs have been the targets of several commonly used diuretic drugs, including hydrochlorothiazide, furosemide, and bumetanide. Genetic mutations of NCC and NKCC2 cause congenital renal tubular disorders and lead to renal salt-losing hypotension, secondary hyperreninemia, and hypokalemic metabolic alkalosis. New studies reveal that CCCs along with their regulatory WNK (Kinase with no lysine (K)), and SPAK (Ste20-related proline-alanine-rich kinase)/OSR1(oxidative stress-responsive kinase-1) are essential for regulating cell volume and maintaining ionic homeostasis in the nervous system, especially roles of the WNK-SPAK-NKCC1 signaling pathway in ischemic brain injury and hypersecretion of cerebrospinal fluid in post-hemorrhagic hydrocephalus. In addition, disruption of Cl- exporter KCC2 has an effect on synaptic inhibition, which may be involved in developing pain, epilepsy, and possibly some neuropsychiatric disorders. Interference with KCC3 leads to peripheral nervous system neuropathy as well as axon and nerve fiber swelling and psychosis. The WNK-SPAK/OSR1-CCCs complex emerges as therapeutic targets for multiple neurological diseases. This review will highlight these new findings.
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Affiliation(s)
- Huachen Huang
- Department of Neurology, The First Affiliate Hospital, Harbin Medical University, Harbin, Heilongjiang, China.
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Suneel Banerjee
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Tong Jiang
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, Hatherly Laboratory, Exeter, EX4 4PS, UK.
| | - Kristopher T. Kahle
- Departments of Neurosurgery, Pediatrics, and Cellular & Molecular Physiology, Centers for Mendelian Genomics, Yale School of Medicine, New Haven, CT, USA.
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
- Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Education and Clinical Center, Pittsburgh, PA, USA.
- Correspondence should be addressed to: Dr. Dandan Sun, Department of Neurology, University of Pittsburgh, Pittsburgh, USA. . Dr. Zhongling Zhang, The First Affiliated Hospital, Harbin Medical University, China.
| | - Zhongling Zhang
- Department of Neurology, The First Affiliate Hospital, Harbin Medical University, Harbin, Heilongjiang, China.
- Correspondence should be addressed to: Dr. Dandan Sun, Department of Neurology, University of Pittsburgh, Pittsburgh, USA. . Dr. Zhongling Zhang, The First Affiliated Hospital, Harbin Medical University, China.
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18
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Yuan Y, O'Malley HA, Smaldino MA, Bouza AA, Hull JM, Isom LL. Delayed maturation of GABAergic signaling in the Scn1a and Scn1b mouse models of Dravet Syndrome. Sci Rep 2019; 9:6210. [PMID: 30996233 PMCID: PMC6470170 DOI: 10.1038/s41598-019-42191-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 03/25/2019] [Indexed: 01/25/2023] Open
Abstract
Dravet syndrome (DS) is a catastrophic developmental and epileptic encephalopathy characterized by severe, pharmacoresistant seizures and the highest risk of Sudden Unexpected Death in Epilepsy (SUDEP) of all epilepsy syndromes. Here, we investigated the time course of maturation of neuronal GABAergic signaling in the Scn1b-/- and Scn1a+/- mouse models of DS. We found that GABAergic signaling remains immature in both DS models, with a depolarized reversal potential for GABAA-evoked currents compared to wildtype in the third postnatal week. Treatment of Scn1b-/- mice with bumetanide resulted in a delay in SUDEP onset compared to controls in a subset of mice, without prevention of seizure activity or amelioration of failure to thrive. We propose that delayed maturation of GABAergic signaling may contribute to epileptogenesis in SCN1B- and SCN1A-linked DS. Thus, targeting the polarity of GABAergic signaling in brain may be an effective therapeutic strategy to reduce SUDEP risk in DS.
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Affiliation(s)
- Yukun Yuan
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109-5632, USA
| | - Heather A O'Malley
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109-5632, USA
| | - Melissa A Smaldino
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109-5632, USA
- Department of Biology, Ball State University, Muncie, IN, 47306, USA
| | - Alexandra A Bouza
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109-5632, USA
| | - Jacob M Hull
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, 48109-2215, USA
| | - Lori L Isom
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109-5632, USA.
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI, 48109-2215, USA.
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19
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Flinck M, Kramer SH, Pedersen SF. Roles of pH in control of cell proliferation. Acta Physiol (Oxf) 2018; 223:e13068. [PMID: 29575508 DOI: 10.1111/apha.13068] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 02/17/2018] [Accepted: 03/19/2018] [Indexed: 02/06/2023]
Abstract
Precise spatiotemporal regulation of intracellular pH (pHi ) is a prerequisite for normal cell function, and changes in pHi or pericellular pH (pHe ) exert important signalling functions. It is well established that proliferation of mammalian cells is dependent on a permissive pHi in the slightly alkaline range (7.0-7.2). It is also clear that mitogen signalling in nominal absence of HCO3- is associated with an intracellular alkalinization (~0.3 pH unit above steady-state pHi ), which is secondary to activation of Na+ /H+ exchange. However, it remains controversial whether this increase in pHi is part of the mitogenic signal cascade leading to cell cycle entry and progression, and whether it is relevant under physiological conditions. Furthermore, essentially all studies of pHi in mammalian cell proliferation have focused on the mitogen-induced G0-G1 transition, and the regulation and roles of pHi during the cell cycle remain poorly understood. The aim of this review is to summarize and critically discuss the possible roles of pHi and pHe in cell cycle progression. While the focus is on the mammalian cell cycle, important insights from studies in lower eukaryotes are also discussed. We summarize current evidence of links between cell cycle progression and pHi and discuss possible pHi - and pHe sensors and signalling pathways relevant to mammalian proliferation control. The possibility that changes in pHi during cell cycle progression may be an integral part of the checkpoint control machinery is explored. Finally, we discuss the relevance of links between pH and proliferation in the context of the perturbed pH homoeostasis and acidic microenvironment of solid tumours.
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Affiliation(s)
- M. Flinck
- Section for Cell Biology and Physiology; Department of Biology; Faculty of Science; University of Copenhagen; Copenhagen Denmark
| | - S. H. Kramer
- Section for Cell Biology and Physiology; Department of Biology; Faculty of Science; University of Copenhagen; Copenhagen Denmark
| | - S. F. Pedersen
- Section for Cell Biology and Physiology; Department of Biology; Faculty of Science; University of Copenhagen; Copenhagen Denmark
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20
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Ciocci Pardo A, Díaz RG, González Arbeláez LF, Pérez NG, Swenson ER, Mosca SM, Alvarez BV. Benzolamide perpetuates acidic conditions during reperfusion and reduces myocardial ischemia-reperfusion injury. J Appl Physiol (1985) 2017; 125:340-352. [PMID: 29357509 DOI: 10.1152/japplphysiol.00957.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
During ischemia, increased anaerobic glycolysis results in intracellular acidosis. Activation of alkalinizing transport mechanisms associated with carbonic anhydrases (CAs) leads to myocardial intracellular Ca2+ increase. We characterize the effects of inhibition of CA with benzolamide (BZ) during cardiac ischemia-reperfusion (I/R). Langendorff-perfused isolated rat hearts were subjected to 30 min of global ischemia and 60 min of reperfusion. Other hearts were treated with BZ (5 μM) during the initial 10 min of reperfusion or perfused with acid solution (AR, pH 6.4) during the first 3 min of reperfusion. p38MAPK, a kinase linked to membrane transporters and involved in cardioprotection, was examined in hearts treated with BZ in presence of the p38MAPK inhibitor SB202190 (10 μM). Infarct size (IZ) and myocardial function were assessed, and phosphorylated forms of p38MAPK, Akt, and PKCε were evaluated by immunoblotting. We determined the rate of intracellular pH (pHi) normalization after transient acid loading in the absence and presence of BZ or BZ + SB202190 in heart papillary muscles (HPMs). Mitochondrial membrane potential (ΔΨm), Ca2+ retention capacity and Ca2+-mediated swelling after I/R were also measured. BZ, similarly to AR, reduced IZ, improved postischemic recovery of myocardial contractility, increased phosphorylation of Akt, PKCε, and p38MAPK, and normalized ΔΨm and Ca2+ homeostasis, effects abolished after p38MAPK inhibition. In HPMs, BZ slowed pHi recovery, an effect that was restored after p38MAPK inhibition. We conclude that prolongation of acidic conditions during reperfusion by BZ could be responsible for the cardioprotective benefits of reduced infarction and better myocontractile function, through p38MAPK-dependent pathways. NEW & NOTEWORTHY Carbonic anhydrase inhibition by benzolamide (BZ) maintains acidity, decreases infarct size, and improves postischemic myocardial dysfunction in ischemia-reperfusion (I/R) hearts. Protection afforded by BZ mimicked the beneficial effects elicited by an acidic solution (AR). Increased phosphorylation of p38MAPK occurs in I/R hearts reperfused with BZ or with AR. Mitochondria from I/R hearts possess abnormal Ca2+ handling and a more depolarized membrane potential compared with control hearts, and these changes were restored by treatment with BZ or AR.
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Affiliation(s)
- Alejandro Ciocci Pardo
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Romina G Díaz
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Luisa F González Arbeláez
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Néstor G Pérez
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Erik R Swenson
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Washington, Department of Veterans Affairs Puget Sound Health Care System , Seattle, Washington
| | - Susana M Mosca
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
| | - Bernardo V Alvarez
- Centro de Investigaciones Cardiovasculares CIC-CONICET, Facultad de Ciencias Médicas, Universidad Nacional de La Plata , La Plata , Argentina
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21
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Pedersen AK, Mendes Lopes de Melo J, Mørup N, Tritsaris K, Pedersen SF. Tumor microenvironment conditions alter Akt and Na +/H + exchanger NHE1 expression in endothelial cells more than hypoxia alone: implications for endothelial cell function in cancer. BMC Cancer 2017; 17:542. [PMID: 28806945 PMCID: PMC5556346 DOI: 10.1186/s12885-017-3532-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 08/03/2017] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Chronic angiogenesis is a hallmark of most tumors and takes place in a hostile tumor microenvironment (TME) characterized by hypoxia, low nutrient and glucose levels, elevated lactate and low pH. Despite this, most studies addressing angiogenic signaling use hypoxia as a proxy for tumor conditions. Here, we compared the effects of hypoxia and TME conditions on regulation of the Na+/H+ exchanger NHE1, Ser/Thr kinases Akt1-3, and downstream effectors in endothelial cells. METHODS Human umbilical vein endothelial cells (HUVEC) and Ea.hy926 endothelial cells were exposed to simulated TME (1% hypoxia, low serum, glucose, pH, high lactate) or 1% hypoxia for 24 or 48 h, with or without NHE1 inhibition or siRNA-mediated knockdown. mRNA and protein levels of NHE1, Akt1-3, and downstream effectors were assessed by qPCR and Western blotting, vascular endothelial growth factor (VEGF) release by ELISA, and motility by scratch assay. RESULTS Within 24 h, HIF-1α level and VEGF mRNA level were increased robustly by TME and modestly by hypoxia alone. The NHE1 mRNA level was decreased by both hypoxia and TME, and NHE1 protein was reduced by TME in Ea.hy926 cells. Akt1-3 mRNA was detected in HUVEC and Ea.hy926 cells, Akt1 most abundantly. Akt1 protein expression was reduced by TME yet unaffected by hypoxia, while Akt phosphorylation was increased by TME. The Akt loss was partly reversed by MCF-7 human breast cancer cell conditioned medium, suggesting that in vivo, the cancer cell secretome may compensate for adverse effects of TME on endothelial cells. TME, yet not hypoxia, reduced p70S6 kinase activity and ribosomal protein S6 phosphorylation and increased eIF2α phosphorylation, consistent with inhibition of protein translation. Finally, TME reduced Retinoblastoma protein phosphorylation and induced poly-ADP-ribose polymerase (PARP) cleavage consistent with inhibition of proliferation and induction of apoptosis. NHE1 knockdown, mimicking the effect of TME on NHE1 expression, reduced Ea.hy926 migration. TME effects on HIF-1α, VEGF, Akt, translation, proliferation or apoptosis markers were unaffected by NHE1 knockdown/inhibition. CONCLUSIONS NHE1 and Akt are downregulated by TME conditions, more potently than by hypoxia alone. This inhibits endothelial cell migration and growth in a manner likely modulated by the cancer cell secretome.
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Affiliation(s)
- A K Pedersen
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - J Mendes Lopes de Melo
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - N Mørup
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200, Copenhagen, Denmark
| | - K Tritsaris
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Panum Institute, Blegdamsvej 3B, 2200, Copenhagen, Denmark.
| | - S F Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, Universitetsparken 13, 2100, Copenhagen, Denmark.
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22
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Chaban YHG, Chen Y, Hertz E, Hertz L. Severe Convulsions and Dysmyelination in Both Jimpy and Cx32/47 -/- Mice may Associate Astrocytic L-Channel Function with Myelination and Oligodendrocytic Connexins with Internodal K v Channels. Neurochem Res 2017; 42:1747-1766. [PMID: 28214987 DOI: 10.1007/s11064-017-2194-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 01/23/2017] [Accepted: 01/24/2017] [Indexed: 12/12/2022]
Abstract
The Jimpy mouse illustrates the importance of interactions between astrocytes and oligodendrocytes. It has a mutation in Plp coding for proteolipid protein and DM20. Its behavior is normal at birth but from the age of ~2 weeks it shows severe convulsions associated with oligodendrocyte/myelination deficits and early death. A normally occurring increase in oxygen consumption by highly elevated K+ concentrations is absent in Jimpy brain slices and cultured astrocytes, reflecting that Plp at early embryonic stages affects common precursors as also shown by the ability of conditioned medium from normal astrocytes to counteract histological abnormalities. This metabolic response is now known to reflect opening of L-channels for Ca2+. The resulting deficiency in Ca2+ entry has many consequences, including lack of K+-stimulated glycogenolysis and release of gliotransmitter ATP. Lack of purinergic stimulation compromises oligodendrocyte survival and myelination and affects connexins and K+ channels. Mice lacking the oligodendrocytic connexins Cx32 and 47 show similar neurological dysfunction as Jimpy. This possibly reflects that K+ released by intermodal axonal Kv channels is transported underneath a loosened myelin sheath instead of reaching the extracellular space via connexin-mediated transport to oligodendrocytes, followed by release and astrocytic Na+,K+-ATPase-driven uptake with subsequent Kir4.1-facilitated release and neuronal uptake.
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Affiliation(s)
| | - Ye Chen
- Henry M. Jackson Foundation, Bethesda, MD, 20817, USA
| | - Elna Hertz
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, People's Republic of China
| | - Leif Hertz
- Laboratory of Metabolic Brain Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, People's Republic of China.
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23
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Rosenthal LM, Tong G, Walker C, Wowro SJ, Krech J, Pfitzer C, Justus G, Berger F, Schmitt KRL. Neuroprotection via RNA-binding protein RBM3 expression is regulated by hypothermia but not by hypoxia in human SK-N-SH neurons. HYPOXIA 2017; 5:33-43. [PMID: 28580361 PMCID: PMC5448696 DOI: 10.2147/hp.s132462] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Therapeutic hypothermia is an established treatment for perinatal asphyxia. Yet, many term infants continue to die or suffer from neurodevelopmental disability. Several experimental studies have demonstrated a beneficial effect of mild-to-moderate hypothermia after hypoxic injury, but the understanding of hypothermia-induced neuroprotection remains incomplete. In general, global protein synthesis is attenuated by hypothermia, but a small group of RNA-binding proteins including the RNA-binding motif 3 (RBM3) is upregulated in response to cooling. The aim of this study was to establish an in vitro model to investigate the effects of hypoxia and hypothermia on neuronal cell survival, as well as to examine the kinetics of concurrent cold-shock protein RBM3 gene expression. METHODS Experiments were performed by using human SK-N-SH neurons exposed to different oxygen concentrations (21%, 8%, or 0.2% O2) for 24 hours followed by moderate hypothermia (33.5°C) or normothermia for 24, 48, or 72 hours. Cell death was determined by quantification of lactate dehydrogenase and neuron-specific enolase releases into the cell cultured medium, and cell morphology was assessed by using immunofluorescence staining. The regulation of RBM3 gene expression was assessed by reverse transcriptase-quantitative polymerase chain reaction and Western blot analysis. RESULTS Exposure to hypoxia (0.2% O2) for 24 hours resulted in significantly increased cell death in SK-N-SH neurons, whereas exposure to 8% O2 had no significant impact on cell viability. Post-hypoxia treatment with moderate hypothermia for 48 or 72 hours rescued the neurons from hypoxia-induced cell death. Moreover, exposure to severe hypoxia led to observable cell swelling, which was also attenuated by moderate hypothermia. Finally, moderate hypothermia but not hypoxia led to the induction of RBM3 expression on both transcriptional and translational levels. CONCLUSION Moderate hypothermia protects neurons from hypoxia-induced cell death. The expression of the cold-shock protein RBM3 is induced by moderate hypothermia and could be one possible mediator of hypothermia-induced neuroprotection.
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Affiliation(s)
- Lisa-Maria Rosenthal
- Department of Congenital Heart Disease/Pediatric Cardiology, German Heart Institute Berlin
| | - Giang Tong
- Department of Congenital Heart Disease/Pediatric Cardiology, German Heart Institute Berlin
| | - Christoph Walker
- Department of Congenital Heart Disease/Pediatric Cardiology, German Heart Institute Berlin
| | - Sylvia J Wowro
- Department of Congenital Heart Disease/Pediatric Cardiology, German Heart Institute Berlin
| | - Jana Krech
- Department of Congenital Heart Disease/Pediatric Cardiology, German Heart Institute Berlin
| | - Constanze Pfitzer
- Department of Congenital Heart Disease/Pediatric Cardiology, German Heart Institute Berlin.,Berlin Institute of Health (BIH)
| | - Georgia Justus
- Department of Congenital Heart Disease/Pediatric Cardiology, German Heart Institute Berlin
| | - Felix Berger
- Department of Congenital Heart Disease/Pediatric Cardiology, German Heart Institute Berlin.,Department of Pediatric Cardiology, Charité - University Medical Center, Berlin, Germany
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24
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Pedersen SF, Novak I, Alves F, Schwab A, Pardo LA. Alternating pH landscapes shape epithelial cancer initiation and progression: Focus on pancreatic cancer. Bioessays 2017; 39. [DOI: 10.1002/bies.201600253] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Stine F. Pedersen
- Section for Cell Biology and Physiology; Department of Biology; University of Copenhagen; Copenhagen Denmark
| | - Ivana Novak
- Section for Cell Biology and Physiology; Department of Biology; University of Copenhagen; Copenhagen Denmark
| | - Frauke Alves
- Max Planck Institute of Experimental Medicine; Göttingen Germany
- Institute for Diagnostic and Interventional Radiology; University Medical Center; Göttingen Germany
- Department of Hematology and Medical Oncology; University Medical Center; Göttingen Germany
| | - Albrecht Schwab
- Institute of Physiology II; University of Münster; Münster Germany
| | - Luis A. Pardo
- Max Planck Institute of Experimental Medicine; Göttingen Germany
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25
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Hertz L, Chen Y. Importance of astrocytes for potassium ion (K+) homeostasis in brain and glial effects of K+ and its transporters on learning. Neurosci Biobehav Rev 2016; 71:484-505. [DOI: 10.1016/j.neubiorev.2016.09.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/12/2016] [Accepted: 09/23/2016] [Indexed: 10/20/2022]
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26
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Zhang J, Gao G, Begum G, Wang J, Khanna AR, Shmukler BE, Daubner GM, de los Heros P, Davies P, Varghese J, Bhuiyan MIH, Duan J, Zhang J, Duran D, Alper SL, Sun D, Elledge SJ, Alessi DR, Kahle KT. Functional kinomics establishes a critical node of volume-sensitive cation-Cl - cotransporter regulation in the mammalian brain. Sci Rep 2016; 6:35986. [PMID: 27782176 PMCID: PMC5080614 DOI: 10.1038/srep35986] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/04/2016] [Indexed: 02/08/2023] Open
Abstract
Cell volume homeostasis requires the dynamically regulated transport of ions across the plasmalemma. While the ensemble of ion transport proteins involved in cell volume regulation is well established, the molecular coordinators of their activities remain poorly characterized. We utilized a functional kinomics approach including a kinome-wide siRNA-phosphoproteomic screen, a high-content kinase inhibitor screen, and a kinase trapping-Orbitrap mass spectroscopy screen to systematically identify essential kinase regulators of KCC3 Thr991/Thr1048 phosphorylation - a key signaling event in cell swelling-induced regulatory volume decrease (RVD). In the mammalian brain, we found the Cl--sensitive WNK3-SPAK kinase complex, required for cell shrinkage-induced regulatory volume decrease (RVI) via the stimulatory phosphorylation of NKCC1 (Thr203/Thr207/Thr212), is also essential for the inhibitory phosphorylation of KCC3 (Thr991/Thr1048). This is mediated in vivo by an interaction between the CCT domain in SPAK and RFXV/I domains in WNK3 and NKCC1/KCC3. Accordingly, genetic or pharmacologic WNK3-SPAK inhibition prevents cell swelling in response to osmotic stress and ameliorates post-ischemic brain swelling through a simultaneous inhibition of NKCC1-mediated Cl- uptake and stimulation of KCC3-mediated Cl- extrusion. We conclude that WNK3-SPAK is an integral component of the long-sought "Cl-/volume-sensitive kinase" of the cation-Cl- cotransporters, and functions as a molecular rheostat of cell volume in the mammalian brain.
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Affiliation(s)
- Jinwei Zhang
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
- Departments of Neurosurgery and Pediatrics, Yale School of Medicine, New Haven, CT 06511 USA
| | - Geng Gao
- Division of Genetics, Brigham and Women’s Hospital, Boston, MA 02115 USA
| | - Gulnaz Begum
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jinhua Wang
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
- Department of Biological Chemistry & Molecular Pharmacology, Harvard Medical School, 250 Longwood Ave, SGM 628, Boston, MA 02115, USA
| | - Arjun R. Khanna
- Department of Neurosurgery, Massachusetts General Hospital, Boston, MA 02114 USA
| | - Boris E. Shmukler
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA -022154 USA
- Department of Medicine, Harvard Medical School, Boston, MA -022154, USA
| | - Gerrit M. Daubner
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Paola de los Heros
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Paul Davies
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Joby Varghese
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | | | - Jinjing Duan
- Departments of Neurosurgery and Pediatrics, Yale School of Medicine, New Haven, CT 06511 USA
- Department of Cardiology, Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts 02115, USA
| | - Jin Zhang
- Department of Cardiology, Howard Hughes Medical Institute, Boston Children’s Hospital, Boston, Massachusetts 02115, USA
| | - Daniel Duran
- Departments of Neurosurgery and Pediatrics, Yale School of Medicine, New Haven, CT 06511 USA
| | - Seth L. Alper
- Division of Nephrology and Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA -022154 USA
- Department of Medicine, Harvard Medical School, Boston, MA -022154, USA
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA, USA
| | - Stephen J. Elledge
- Department of Genetics, Harvard University Medical School, Howard Hughes Medical Institute, Boston, Massachusetts 02115 USA
| | - Dario R. Alessi
- MRC Protein Phosphorylation and Ubiquitylation Unit, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland
| | - Kristopher T. Kahle
- Departments of Pediatrics and Cellular & Molecular Physiology; Interdepartmental Neuroscience Program; and Centers for Mendelian Genomics, Yale School of Medicine, New Haven, CT 06511 USA
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27
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Boscia F, Begum G, Pignataro G, Sirabella R, Cuomo O, Casamassa A, Sun D, Annunziato L. Glial Na(+) -dependent ion transporters in pathophysiological conditions. Glia 2016; 64:1677-97. [PMID: 27458821 DOI: 10.1002/glia.23030] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 06/22/2016] [Accepted: 06/29/2016] [Indexed: 12/12/2022]
Abstract
Sodium dynamics are essential for regulating functional processes in glial cells. Indeed, glial Na(+) signaling influences and regulates important glial activities, and plays a role in neuron-glia interaction under physiological conditions or in response to injury of the central nervous system (CNS). Emerging studies indicate that Na(+) pumps and Na(+) -dependent ion transporters in astrocytes, microglia, and oligodendrocytes regulate Na(+) homeostasis and play a fundamental role in modulating glial activities in neurological diseases. In this review, we first briefly introduced the emerging roles of each glial cell type in the pathophysiology of cerebral ischemia, Alzheimer's disease, epilepsy, Parkinson's disease, Amyotrophic Lateral Sclerosis, and myelin diseases. Then, we discussed the current knowledge on the main roles played by the different glial Na(+) -dependent ion transporters, including Na(+) /K(+) ATPase, Na(+) /Ca(2+) exchangers, Na(+) /H(+) exchangers, Na(+) -K(+) -Cl(-) cotransporters, and Na(+) - HCO3- cotransporter in the pathophysiology of the diverse CNS diseases. We highlighted their contributions in cell survival, synaptic pathology, gliotransmission, pH homeostasis, and their role in glial activation, migration, gliosis, inflammation, and tissue repair processes. Therefore, this review summarizes the foundation work for targeting Na(+) -dependent ion transporters in glia as a novel strategy to control important glial activities associated with Na(+) dynamics in different neurological disorders. GLIA 2016;64:1677-1697.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Gulnaz Begum
- Department of Neurology, University of Pittsburgh Medical School
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Rossana Sirabella
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Ornella Cuomo
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Antonella Casamassa
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh Medical School.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, Pennsylvania, 15213
| | - Lucio Annunziato
- Division of Pharmacology, Department of Neuroscience, Reproductive, and Odontostomatological Sciences, School of Medicine, Federico II University of Naples, Naples, Italy
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28
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Chien EJ, Hsu CH, Chang VHJ, Lin EPY, Kuo TPT, Chien CH, Lin HY. In human T cells mifepristone antagonizes glucocorticoid non-genomic rapid responses in terms of Na(+)/H(+)-exchange 1 activity, but not ezrin/radixin/moesin phosphorylation. Steroids 2016; 111:29-36. [PMID: 26773750 DOI: 10.1016/j.steroids.2016.01.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 01/04/2016] [Indexed: 01/01/2023]
Abstract
Glucocorticoids (GCs) and progesterone have been employed as immunosuppressive agents during pregnancy for many years. Intracellular acidification by GCs is due to a rapid non-genomic inhibition of membrane Na(+)/H(+)-exchange 1 (NHE1) activity and is followed by immunosuppression of PHA-stimulated proliferation. NHE1 is tethered to the cortical actin cytoskeleton through ezrin/radixin/moesin (ERM) proteins within lipid rafts; these regulate cell shape, migration and resistance to apoptosis. We explored whether mifepristone (RU486), an antagonist of GCs in T cells, is able to completely block rapid non-genomic responses, namely NHE1 activity and the phosphorylation C-terminal residues of ERM proteins at threonine (cp-ERM). GCs stimulate a rapid non-genomic cp-ERM response in cells within 5min. RU486 antagonized the GC-induced rapid decrease in NHE1 activity, and arrested PHA-stimulated T cells at G0/G1 phase but had no effect on the rapid increase in cp-ERM, which persisted for 24h. However, the cp-ERM response was blocked by staurosporine in both resting and GC stimulated cells. The results of RU486 antagonized the GC induced rapid decrease in NHE1 ion transport activity, but not the increase cp-ERM. This suggests that RU486 in T cells exerts its antagonistic effects at NHE1 containing plasma membrane sites and not where cp-ERM links lipid rafts to cortical cytoskeletons.
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Affiliation(s)
- Eileen Jea Chien
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC; Department of Healthcare Administration, Asia University, Taichung 41354, Taiwan, ROC; Graduate Institute of Basic Medical Science, College of Medicine, China Medical University, Taichung 40402, Taiwan, ROC.
| | - Ching-Hui Hsu
- Division of Allergy-Immunology-Rheumatology, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC
| | - Vincent Han-Jhih Chang
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC
| | - Enoch Pin-Yi Lin
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC
| | - Trista Pin-Tsun Kuo
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC
| | - Chau-Heng Chien
- Institute and Department of Physiology, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC
| | - Hsiao-Yi Lin
- Department of Medicine, School of Medicine, National Yang-Ming University, Taipei 11221, Taiwan, ROC; Division of Allergy-Immunology-Rheumatology, Taipei Veterans General Hospital, Taipei 11217, Taiwan, ROC.
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29
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Multifactorial Effects on Different Types of Brain Cells Contribute to Ammonia Toxicity. Neurochem Res 2016; 42:721-736. [PMID: 27286679 DOI: 10.1007/s11064-016-1966-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 05/20/2016] [Accepted: 05/24/2016] [Indexed: 12/12/2022]
Abstract
Effects of ammonia on astrocytes play a major role in hepatic encephalopathy, acute liver failure and other diseases caused by increased arterial ammonia concentrations (e.g., inborn errors of metabolism, drug or mushroom poisoning). There is a direct correlation between arterial ammonia concentration, brain ammonia level and disease severity. However, the pathophysiology of hyperammonemic diseases is disputed. One long recognized factor is that increased brain ammonia triggers its own detoxification by glutamine formation from glutamate. This is an astrocytic process due to the selective expression of the glutamine synthetase in astrocytes. A possible deleterious effect of the resulting increase in glutamine concentration has repeatedly been discussed and is supported by improvement of some pathologic effects by GS inhibition. However, this procedure also inhibits a large part of astrocytic energy metabolism and may prevent astrocytes from responding to pathogenic factors. A decrease of the already low glutamate concentration in astrocytes due to increased synthesis of glutamine inhibits the malate-aspartate shuttle and energy metabolism. A more recently described pathogenic factor is the resemblance between NH4+ and K+ in their effects on the Na+,K+-ATPase and the Na+,K+, 2 Cl- and water transporter NKCC1. Stimulation of the Na+,K+-ATPase driven NKCC1 in both astrocytes and endothelial cells is essential for the development of brain edema. Na+,K+-ATPase stimulation also activates production of endogenous ouabains. This leads to oxidative and nitrosative damage and sensitizes NKCC1. Administration of ouabain antagonists may accordingly have therapeutic potential in hyperammonemic diseases.
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30
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Halonen J, Hinton AS, Frisina RD, Ding B, Zhu X, Walton JP. Long-term treatment with aldosterone slows the progression of age-related hearing loss. Hear Res 2016; 336:63-71. [PMID: 27157488 DOI: 10.1016/j.heares.2016.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 04/19/2016] [Accepted: 05/03/2016] [Indexed: 10/21/2022]
Abstract
Age-related hearing loss (ARHL), clinically referred to as presbycusis, is one of the three most prevalent chronic medical conditions of our elderly, with the majority of persons over the age of 60 suffering from some degree of ARHL. The progressive loss of auditory sensitivity and perceptual capability results in significant declines in workplace productivity, quality of life, cognition and abilities to communicate effectively. Aldosterone is a mineralocorticoid hormone produced in the adrenal glands and plays a role in the maintenance of key ion pumps, including the Na-K(+)-Cl co-transporter 1 or NKCC1, which is involved in homeostatic maintenance of the endocochlear potential. Previously we reported that aldosterone (1 μM) increases NKCC1 protein expression in vitro and that this up-regulation of NKCC1 was not dose-dependent (dosing range from 1 nM to 100 μM). In the current study we measured behavioral and electrophysiological hearing function in middle-aged mice following long-term systemic treatment with aldosterone. We also confirmed that blood pressure remained stable during treatment and that NKCC1 protein expression was upregulated. Pre-pulse inhibition of the acoustic startle response was used as a functional measure of hearing, and the auditory brainstem response was used as an objective measure of peripheral sensitivity. Long-term treatment with aldosterone improved both behavioral and physiological measures of hearing (ABR thresholds). These results are the first to demonstrate a protective effect of aldosterone on age-related hearing loss and pave the way for translational drug development, using aldosterone as a key component to prevent or slow down the progression of ARHL.
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Affiliation(s)
- Joshua Halonen
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Ashley S Hinton
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Robert D Frisina
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Bo Ding
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Xiaoxia Zhu
- Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA
| | - Joseph P Walton
- Departments of Communication Sciences and Disorders, University of South Florida, Tampa, FL 33620, USA; Chemical and Biomedical Engineering, University of South Florida, Tampa, FL 33620, USA; Global Center of Speech and Hearing Research, University of South Florida, Tampa, FL 33620, USA.
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31
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Isaksen TJ, Lykke-Hartmann K. Insights into the Pathology of the α2-Na(+)/K(+)-ATPase in Neurological Disorders; Lessons from Animal Models. Front Physiol 2016; 7:161. [PMID: 27199775 PMCID: PMC4854887 DOI: 10.3389/fphys.2016.00161] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/15/2016] [Indexed: 12/12/2022] Open
Abstract
A functional Na+/K+-ATPase consists of a catalytic α subunit and a regulatory β subunit. Four α isoforms of the Na+/K+-ATPase are found in mammals, each with a unique expression pattern and catalytic activity. The α2 isoform, encoded by the ATP1A2 gene, is primarily found in the central nervous system (CNS) and in heart-, skeletal- and smooth muscle tissues. In the CNS, the α2 isoform is mainly expressed in glial cells. In particular, the α2 isoform is found in astrocytes, important for astrocytic K+ clearance and, consequently, the indirect uptake of neurotransmitters. Both processes are essential for proper brain activity, and autosomal dominantly mutations in the ATP1A2 gene cause the neurological disorder Familial hemiplegic migraine type 2 (FHM2). FHM2 is a severe subtype of migraine with aura including temporary numbness or weakness, and affecting only one side of the body. FHM2 patients often suffer from neurological comorbidities such as seizures, sensory disturbances, cognitive impairment, and psychiatric manifestations. The functional consequences of FHM2 disease mutations leads to a partial or complete loss of function of pump activity; however, a clear phenotype-genotype correlation has yet to be elucidated. Gene-modified mouse models targeting the Atp1a2 gene have proved instrumental in the understanding of the pathology of FHM2. Several Atp1a2 knockout (KO) mice targeting different exons have been reported. Homozygous Atp1a2 KO mice die shortly after birth due to respiratory malfunction resulting from abnormal Cl− homeostasis in brainstem neurons. Heterozygous KO mice are viable, but display altered behavior and neurological deficits such as altered spatial learning, decreased motor activity and enhanced fear/anxiety compared to wild type mice. FHM2 knock-in (KI) mouse models carrying the human in vivo disease mutations W887R and G301R have also been reported. Both models display altered cortical spreading depression (CSD) and point to deficits in the glutamatergic system as the main underlying mechanism of FHM2.
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Affiliation(s)
- Toke J Isaksen
- Department of Biomedicine, Aarhus UniversityAarhus, Denmark; Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus UniversityAarhus, Denmark
| | - Karin Lykke-Hartmann
- Department of Biomedicine, Aarhus UniversityAarhus, Denmark; Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Department of Molecular Biology and Genetics, Aarhus UniversityAarhus, Denmark; Aarhus Institute of Advanced Studies, Aarhus UniversityAarhus, Denmark
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32
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Wang P, Li L, Zhang Z, Kan Q, Gao F, Chen S. Time-dependent activity of Na+/H+ exchanger isoform 1 and homeostasis of intracellular pH in astrocytes exposed to CoCl2 treatment. Mol Med Rep 2016; 13:4443-50. [PMID: 27035646 DOI: 10.3892/mmr.2016.5067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 02/11/2016] [Indexed: 11/06/2022] Open
Abstract
Hypoxia causes injury to the central nervous system during stroke and has significant effects on pH homeostasis. Na+/H+ exchanger isoform 1 (NHE1) is important in the mechanisms of hypoxia and intracellular pH (pHi) homeostasis. As a well-established hypoxia-mimetic agent, CoCl2 stabilizes and increases the expression of hypoxia inducible factor‑1α (HIF-1α), which regulates several genes involved in pH balance, including NHE1. However, it is not fully understood whether NHE1 is activated in astrocytes under CoCl2 treatment. In the current study, pHi and NHE activity were analyzed using the pHi‑sensitive dye BCECF‑AM. Using cariporide (an NHE1‑specific inhibitor) and EIPA (an NHE nonspecific inhibitor), the current study demonstrated that it was NHE1, not the other NHE isoforms, that was important in regulating pHi homeostasis in astrocytes during CoCl2 treatment. Additionally, the present study observed that, during the early period of CoCl2 treatment (the first 2 h), NHE1 activity and pHi dropped immediately, and NHE1 mRNA expression was reduced compared with control levels, whereas expression levels of the NHE1 protein had not yet changed. In the later period of CoCl2 treatment, NHE1 activity and pHi significantly increased compared with the control levels, as did the mRNA and protein expression levels of NHE1. Furthermore, the cell viability and injury of astrocytes was not changed during the initial 8 h of CoCl2 treatment; their deterioration was associated with the higher levels of pHi and NHE1 activity. The current study concluded that NHE1 activity and pHi homeostasis are regulated by CoCl2 treatment in a time-dependent manner in astrocytes, and may be responsible for the changes in cell viability and injury observed under hypoxia-mimetic conditions induced by CoCl2 treatment.
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Affiliation(s)
- Peng Wang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Ling Li
- Department of Palliative and Hospice Care, The Ninth People's Hospital of Zhengzhou, Zhengzhou, Henan 450053, P.R. China
| | - Zhenxiang Zhang
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Quancheng Kan
- Clinical Pharmacology Base, Department of Infectious Disease, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Feng Gao
- Department of Neuroimmunology, Henan Academy of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
| | - Suyan Chen
- Department of Basic Medicine, Nursing College, Zhengzhou University, Zhengzhou, Henan 450052, P.R. China
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Astrocyte Cultures Mimicking Brain Astrocytes in Gene Expression, Signaling, Metabolism and K + Uptake and Showing Astrocytic Gene Expression Overlooked by Immunohistochemistry and In Situ Hybridization. Neurochem Res 2016; 42:254-271. [PMID: 26818759 DOI: 10.1007/s11064-016-1828-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/01/2016] [Accepted: 01/04/2016] [Indexed: 01/31/2023]
Abstract
Based on differences in gene expression between cultured astrocytes and freshly isolated brain astrocytes it has been claimed that cultured astrocytes poorly reflect the characteristics of their in vivo counterparts. This paper shows that this is not the case with the cultures of mouse astrocytes we have used since 1978. The culture is prepared following guidelines provided by Drs. Monique Sensenbrenner and John Booher, with the difference that dibutyryl cyclic AMP is added to the culture medium from the beginning of the third week. This addition has only minor effects on glucose and glutamate metabolism, but it is crucial for effects by elevated K+ concentrations and for Ca2+ homeostasis, important aspects of astrocyte function. Work by Liang Peng and her colleagues has shown identity between not only gene expression but also drug-induced gene upregulations and editings in astrocytes cultured by this method and astrocytes freshly isolated from brains of drug-treated animals. Dr. Norenberg's laboratory has demonstrated identical upregulation of the cotransporter NKCC1 in ammonia-exposed astrocytes and rats with liver failure. Similarity between cultured and freshly isolated astrocytes has also been shown in metabolism, K+ uptake and several aspects of signaling. However, others have shown that the gene for the glutamate transporter GLT1 is not expressed, and rat cultures show some abnormalities in K+ effects. Nevertheless, the overall reliability of the cultured cells is important because immunohistochemistry and in situ hybridization poorly demonstrate many astrocytic genes, e.g., those of nucleoside transporters, and even microarray analysis of isolated cells can be misleading.
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Matic I, Cocco S, Ferraina C, Martin-Jimenez R, Florenzano F, Crosby J, Lupi R, Amadoro G, Russell C, Pignataro G, Annunziato L, Abramov AY, Campanella M. Neuroprotective coordination of cell mitophagy by the ATPase Inhibitory Factor 1. Pharmacol Res 2016; 103:56-68. [PMID: 26484591 DOI: 10.1016/j.phrs.2015.10.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 10/12/2015] [Accepted: 10/13/2015] [Indexed: 01/03/2023]
Abstract
The mitochondrial ATPase Inhibitory Factor 1 (hereafter referred to as IF1) blocks the reversal of the F1Fo-ATPsynthase to prevent detrimental consumption of cellular ATP and associated demise. Herein, we infer further its molecular physiology by assessing its protective function in neurons during conditions of challenged homeostatic respiration. By adopting in vitro and in vivo protocols of hypoxia/ischemia and re-oxygenation, we show that a shift in the IF1:F1Fo-ATPsynthase expression ratio occurs in neurons. This increased IF1 level is essential to induce accumulation of the PTEN-induced putative kinase 1 (PINK-1) and recruitment of the mitophagic ubiquitin ligase PARK-2 to promote autophagic "control" of the mitochondrial population. In IF1 overexpressing neurons ATP depletion is reduced during hypoxia/ischemia and the mitochondrial membrane potential (ΔYm) resilient to re-oxygenation as well as resistant to electrogenic, Ca(2+) dependent depolarization. These data suggest that in mammalian neurons mitochondria adapt to respiratory stress by upregulating IF1, which exerts a protective role by coordinating pro-survival cell mitophagy and bioenergetics resilience.
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Affiliation(s)
- Ivana Matic
- Department of Biology, University of Rome "TorVergata", 00133 Rome, Italy
| | - Stefania Cocco
- EBRI-European Brain Research Institute, 00143 Rome, Italy
| | - Caterina Ferraina
- Department of Biology, University of Rome "TorVergata", 00133 Rome, Italy; Regina Elena-National Cancer Institute, 00144 Rome, Italy
| | - Rebeca Martin-Jimenez
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street NW1 0TU, United Kingdom
| | | | - James Crosby
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street NW1 0TU, United Kingdom
| | - Ramona Lupi
- EBRI-European Brain Research Institute, 00143 Rome, Italy
| | - Giusy Amadoro
- EBRI-European Brain Research Institute, 00143 Rome, Italy
| | - Claire Russell
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street NW1 0TU, United Kingdom
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, School of Medicine, Federico II University of Naples, Italy; Department of Molecular Neuroscience, Institute of Neurology, University College London, United Kingdom
| | - Lucio Annunziato
- Division of Pharmacology, Department of Neuroscience, School of Medicine, Federico II University of Naples, Italy; Department of Molecular Neuroscience, Institute of Neurology, University College London, United Kingdom
| | - Andrey Y Abramov
- Department of Molecular Neuroscience, Institute of Neurology, University College London, United Kingdom
| | - Michelangelo Campanella
- Department of Comparative Biomedical Sciences, The Royal Veterinary College, University of London, Royal College Street NW1 0TU, United Kingdom; UCL Consortium for Mitochondrial Research, Royal College Street, University of London, United Kingdom; Department of Biology, University of Rome "TorVergata", 00133 Rome, Italy; Regina Elena-National Cancer Institute, 00144 Rome, Italy.
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Sodium-Proton (Na+/H+) Antiporters: Properties and Roles in Health and Disease. Met Ions Life Sci 2016; 16:391-458. [DOI: 10.1007/978-3-319-21756-7_12] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Aksyonov A, Mitrokhin V, Mladenov M. Effects of interleukin-2 on bioelectric activity of rat atrial myocardium under normal conditions and during gradual stretching. Immunol Lett 2015; 167:23-8. [DOI: 10.1016/j.imlet.2015.06.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 05/01/2015] [Accepted: 06/11/2015] [Indexed: 10/23/2022]
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Rose KL, Watson AJ, Drysdale TA, Cepinskas G, Chan M, Rupar CA, Fraser DD. Simulated diabetic ketoacidosis therapy in vitro elicits brain cell swelling via sodium-hydrogen exchange and anion transport. Am J Physiol Endocrinol Metab 2015; 309:E370-9. [PMID: 26081282 DOI: 10.1152/ajpendo.00107.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 06/11/2015] [Indexed: 01/08/2023]
Abstract
A common complication of type 1 diabetes mellitus is diabetic ketoacidosis (DKA), a state of severe insulin deficiency. A potentially harmful consequence of DKA therapy in children is cerebral edema (DKA-CE); however, the mechanisms of therapy-induced DKA-CE are unknown. Our aims were to identify the DKA treatment factors and membrane mechanisms that might contribute specifically to brain cell swelling. To this end, DKA was induced in juvenile mice with the administration of the pancreatic toxins streptozocin and alloxan. Brain slices were prepared and exposed to DKA-like conditions in vitro. Cell volume changes were imaged in response to simulated DKA therapy. Our experiments showed that cell swelling was elicited with isolated DKA treatment components, including alkalinization, insulin/alkalinization, and rapid reductions in osmolality. Methyl-isobutyl-amiloride, a nonselective inhibitor of sodium-hydrogen exchangers (NHEs), reduced cell swelling in brain slices elicited with simulated DKA therapy (in vitro) and decreased brain water content in juvenile DKA mice administered insulin and rehydration therapy (in vivo). Specific pharmacological inhibition of the NHE1 isoform with cariporide also inhibited cell swelling, but only in the presence of the anion transport (AT) inhibitor 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid. DKA did not alter brain NHE1 isoform expression, suggesting that the cell swelling attributed to the NHE1 was activity dependent. In conclusion, our data raise the possibility that brain cell swelling can be elicited by DKA treatment factors and that it is mediated by NHEs and/or coactivation of NHE1 and AT.
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Affiliation(s)
- Keeley L Rose
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada; Children's Health Research Institute, London, Ontario, Canada
| | - Andrew J Watson
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada; Children's Health Research Institute, London, Ontario, Canada
| | - Thomas A Drysdale
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada; Children's Health Research Institute, London, Ontario, Canada; Department of Paediatrics, Western University, London, Ontario, Canada
| | | | - Melissa Chan
- Children's Health Research Institute, London, Ontario, Canada
| | - C Anthony Rupar
- Children's Health Research Institute, London, Ontario, Canada; Department of Paediatrics, Western University, London, Ontario, Canada
| | - Douglas D Fraser
- Department of Physiology and Pharmacology, Western University, London, Ontario, Canada; Children's Health Research Institute, London, Ontario, Canada; Centre for Critical Illness Research, London, Ontario, Canada; Department of Paediatrics, Western University, London, Ontario, Canada; Department of Clinical Neurological Sciences, Western University, London, Ontario, Canada; and Translational Research Centre, London, Ontario, Canada
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Avnstorp MB, Rasmussen P, Brassard P, Seifert T, Overgaard M, Krustrup P, Secher NH, Nordsborg NB. Cerebral water and ion balance remains stable when humans are exposed to acute hypoxic exercise. High Alt Med Biol 2015; 16:18-25. [PMID: 25761236 DOI: 10.1089/ham.2014.1075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Intense physical activity increases the prevalence of acute mountain sickness (AMS) that can occur within 10 h after ascent to altitudes above 1500 m and is likely related to development of cerebral edema. This study evaluated whether disturbed cerebral water and ion homeostasis can be detected when intense exercise is carried out in hypoxia and monitored the influence of muscle metabolism for changes in arterial variables. METHODS On two separate days, in random order, 30 min cycling exercise was performed in either hypoxia (10% O2) or normoxia at an intensity that was exhaustive in the hypoxic trial (∼120 W; n=9). RESULTS Exercise in hypoxia affected muscle metabolism, as evidenced by higher (p<0.05) leg lactate release at 7.5 min and a continuous decline in arterial pH (p<0.001) that was not observed in normoxia. Middle cerebral artery flow velocity increased (p<0.01) with exercise under both circumstances. No cerebral net exchange of Na(+) or K(+) was evident. Likewise, no significant net-exchange of water over the brain was demonstrated and the arterial and jugular venous hemoglobin concentrations were similar. CONCLUSION Challenging exercise in hypoxia for 30 min affected muscle metabolism and increased an index of cerebral blood flow, but cerebral net water and ion homeostasis remained stable. Thus, although AMS develops within hours and may be related to exercise-induced disturbance of cerebral ion and water balance, such changes are not detectable when subjects are exposed to acute 30 min maximal exercise in hypoxia.
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Affiliation(s)
- Magnus B Avnstorp
- 1 Department of Anesthesia, The Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen , Copenhagen, Denmark
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Robel S, Buckingham SC, Boni JL, Campbell SL, Danbolt NC, Riedemann T, Sutor B, Sontheimer H. Reactive astrogliosis causes the development of spontaneous seizures. J Neurosci 2015; 35:3330-45. [PMID: 25716834 PMCID: PMC4339349 DOI: 10.1523/jneurosci.1574-14.2015] [Citation(s) in RCA: 189] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 12/16/2014] [Accepted: 01/12/2015] [Indexed: 11/21/2022] Open
Abstract
Epilepsy is one of the most common chronic neurologic diseases, yet approximately one-third of affected patients do not respond to anticonvulsive drugs that target neurons or neuronal circuits. Reactive astrocytes are commonly found in putative epileptic foci and have been hypothesized to be disease contributors because they lose essential homeostatic capabilities. However, since brain pathology induces astrocytes to become reactive, it is difficult to distinguish whether astrogliosis is a cause or a consequence of epileptogenesis. We now present a mouse model of genetically induced, widespread chronic astrogliosis after conditional deletion of β1-integrin (Itgβ1). In these mice, astrogliosis occurs in the absence of other pathologies and without BBB breach or significant inflammation. Electroencephalography with simultaneous video recording revealed that these mice develop spontaneous seizures during the first six postnatal weeks of life and brain slices show neuronal hyperexcitability. This was not observed in mice with neuronal-targeted β1-integrin deletion, supporting the hypothesis that astrogliosis is sufficient to induce epileptic seizures. Whole-cell patch-clamp recordings from astrocytes further suggest that the heightened excitability was associated with impaired astrocytic glutamate uptake. Moreover, the relative expression of the cation-chloride cotransporters (CCC) NKCC1 (Slc12a2) and KCC2 (Slc12a5), which are responsible for establishing the neuronal Cl(-) gradient that governs GABAergic inhibition were altered and the NKCC1 inhibitor bumetanide eliminated seizures in a subgroup of mice. These data suggest that a shift in the relative expression of neuronal NKCC1 and KCC2, similar to that observed in immature neurons during development, may contribute to astrogliosis-associated seizures.
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Affiliation(s)
- Stefanie Robel
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35209,
| | - Susan C Buckingham
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35209
| | - Jessica L Boni
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35209
| | - Susan L Campbell
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35209
| | - Niels C Danbolt
- Department of Anatomy, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway, and
| | - Therese Riedemann
- Institute of Physiology, Department of Physiological Genomics, Ludwig-Maximilians-University of Munich, 80336 Munich, Germany
| | - Bernd Sutor
- Institute of Physiology, Department of Physiological Genomics, Ludwig-Maximilians-University of Munich, 80336 Munich, Germany
| | - Harald Sontheimer
- Department of Neurobiology, Center for Glial Biology in Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35209
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Hertz L, Xu J, Song D, Du T, Li B, Yan E, Peng L. Astrocytic glycogenolysis: mechanisms and functions. Metab Brain Dis 2015; 30:317-33. [PMID: 24744118 DOI: 10.1007/s11011-014-9536-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 02/24/2014] [Indexed: 12/18/2022]
Abstract
Until the demonstration little more than 20 years ago that glycogenolysis occurs during normal whisker stimulation glycogenolysis was regarded as a relatively uninteresting emergency procedure. Since then, a series of important astrocytic functions has been shown to be critically dependent on glycogenolytic activity to support the signaling mechanisms necessary for these functions to operate. This applies to glutamate formation and uptake and to release of ATP as a transmitter, stimulated by other transmitters or elevated K(+) concentrations and affecting not only other astrocytes but also most other brain cells. It is also relevant for astrocytic K(+) uptake both during the period when the extracellular K(+) concentration is still elevated after neuronal excitation, and capable of stimulating glycogenolytic activity, and during the subsequent undershoot after intense neuronal activity, when glycogenolysis may be stimulated by noradrenaline. Both elevated K(+) concentrations and several transmitters, including the β-adrenergic agonist isoproterenol and vasopressin increase free cytosolic Ca(2+) concentration in astrocytes, which stimulates phosphorylase kinase so that it activates the transformation of the inactive glycogen phosphorylase a to the active phosphorylase b. Contrary to common belief cyclic AMP plays at most a facilitatory role, and only when free cytosolic Ca(2+) concentration is also increased. Cyclic AMP is not increased during activation of glycogenolysis by either elevated K(+) concentrations or the stimulation of the serotonergic 5-HT(2B) receptor. Not all agents that stimulate glycogenolysis do so by directly activating phophorylase kinase--some do so by activating processes requiring glycogenolysis, e.g. for synthesis of glutamate.
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Affiliation(s)
- Leif Hertz
- Department of Clinical Pharmacology, China Medical University, No. 92 Beier Road, Heping District, 110001, Shenyang, Peoples' Republic of China
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Kaur A, Bali A, Singh N, Jaggi AS. Investigating the stress attenuating potential of furosemide in immobilization and electric foot-shock stress models in mice. Naunyn Schmiedebergs Arch Pharmacol 2015; 388:497-507. [PMID: 25604076 DOI: 10.1007/s00210-015-1084-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2014] [Accepted: 01/07/2015] [Indexed: 10/24/2022]
Abstract
The present study was designed to investigate the antistress effect of furosemide (sodium potassium chloride co-transporter inhibitor) in immobilization and foot-shock stress-induced behavioral alterations in the mice. Acute stress was induced in Swiss albino mice either by applying electric foot shocks of 0.6-mA intensity of 1-s duration with 30-s inter-shock interval for 1 h or immobilizing for 150 min. The acute stress-induced behavioral changes were assessed by using actophotometer, hole board, open-field, and social interaction tests. Biochemically, the corticosterone levels were estimated in the serum as a biomarker of hypothalamus-pituitary-adrenal (HPA) axis. Acute stress resulted in the development of behavioral alterations and elevation of the corticosterone levels. Intraperitoneal administration of furosemide (25 and 50 mg/kg) significantly attenuated immobilization and foot-shock stress-induced behavioral changes along with normalization of the corticosterone levels. It may be concluded that furosemide produces beneficial effects in reestablishing the behavioral and biochemical alterations in immobilization and foot-shock-induced acute stress in mice.
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Affiliation(s)
- Aalamjeet Kaur
- Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala, 147002, India
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Hertz L, Song D, Xu J, Peng L, Gibbs ME. Role of the Astrocytic Na(+), K(+)-ATPase in K(+) Homeostasis in Brain: K(+) Uptake, Signaling Pathways and Substrate Utilization. Neurochem Res 2015; 40:2505-16. [PMID: 25555706 DOI: 10.1007/s11064-014-1505-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 12/01/2014] [Accepted: 12/19/2014] [Indexed: 01/13/2023]
Abstract
This paper describes the roles of the astrocytic Na(+), K(+)-ATPase for K(+) homeostasis in brain. After neuronal excitation it alone mediates initial cellular re-accumulation of moderately increased extracellular K(+). At higher K(+) concentrations it is assisted by the Na(+), K(+), 2Cl(-) transporter NKCC1, which is Na(+), K(+)-ATPase-dependent, since it is driven by Na(+), K(+)-ATPase-created ion gradients. Besides stimulation by high K(+), NKCC1 is activated by extracellular hypertonicity. Intense excitation is followed by extracellular K(+) undershoot which is decreased by furosemide, an NKCC1 inhibitor. The powerful astrocytic Na(+), K(+)-ATPase accumulates excess extracellular K(+), since it is stimulated by above-normal extracellular K(+) concentrations. Subsequently K(+) is released via Kir4.1 channels (with no concomitant Na(+) transport) for re-uptake by the neuronal Na(+), K(+)-ATPase which is in-sensitive to increased extracellular K(+), but stimulated by intracellular Na(+) increase. Operation of the astrocytic Na(+), K(+)-ATPase depends upon Na(+), K(+)-ATPase/ouabain-mediated signaling and K(+)-stimulated glycogenolysis, needed in these non-excitable cells for passive uptake of extracellular Na(+), co-stimulating the intracellular Na(+)-sensitive site. A gradual, spatially dispersed release of astrocytically accumulated K(+) will therefore not re-activate the astrocytic Na(+), K(+)-ATPase. The extracellular K(+) undershoot is probably due to extracellular hypertonicity, created by a 3:2 ratio between Na(+), K(+)-ATPase-mediated Na(+) efflux and K(+) influx and subsequent NKCC1-mediated volume regulation. The astrocytic Na(+), K(+)-ATPase is also stimulated by β1-adrenergic signaling, which further stimulates hypertonicity-activation of NKCC1. Brain ischemia leads to massive extracellular K(+) increase and Ca(2+) decrease. A requirement of Na(+), K(+)-ATPase signaling for extracellular Ca(2+) makes K(+) uptake (and brain edema) selectively dependent upon β1-adrenergic signaling and inhibitable by its antagonists.
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Affiliation(s)
- Leif Hertz
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 77 Puhe Road, Shenbei District, Shenyang, 110122, People's Republic of China
| | - Dan Song
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 77 Puhe Road, Shenbei District, Shenyang, 110122, People's Republic of China
| | - Junnan Xu
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 77 Puhe Road, Shenbei District, Shenyang, 110122, People's Republic of China
| | - Liang Peng
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 77 Puhe Road, Shenbei District, Shenyang, 110122, People's Republic of China.
| | - Marie E Gibbs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Clayton, VIC, Australia
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Mokgokong R, Wang S, Taylor CJ, Barrand MA, Hladky SB. Ion transporters in brain endothelial cells that contribute to formation of brain interstitial fluid. Pflugers Arch 2014; 466:887-901. [PMID: 24022703 PMCID: PMC4006130 DOI: 10.1007/s00424-013-1342-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 08/24/2013] [Accepted: 08/24/2013] [Indexed: 02/07/2023]
Abstract
Ions and water transported across the endothelium lining the blood–brain barrier contribute to the fluid secreted into the brain and are important in maintaining appropriate volume and ionic composition of brain interstitial fluid. Changes in this secretion process may occur after stroke. The present study identifies at transcript and protein level ion transporters involved in the movement of key ions and examines how levels of certain of these alter following oxidative stress. Immunohistochemistry provides evidence for Cl−/HCO3− exchanger, AE2, and Na+, HCO3− cotransporters, NBCe1 and NBCn1, on brain microvessels. mRNA analysis by RT-PCR reveals expression of these transporters in cultured rat brain microvascular endothelial cells (both primary and immortalized GPNT cells) and also Na+/H+ exchangers, NHE1 (primary and immortalized) and NHE2 (primary cells only). Knock-down using siRNA in immortalized GPNT cells identifies AE2 as responsible for much of the Cl−/HCO3− exchange following extracellular chloride removal and NHE1 as the transporter that accounts for most of the Na+/H+ exchange following intracellular acidification. Transcript levels of both AE2 and NHE1 are increased following hypoxia/reoxygenation. Further work is now required to determine the localization of the bicarbonate transporters to luminal or abluminal membranes of the endothelial cells as well as to identify and localize additional transport mechanisms that must exist for K+ and Cl−.
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Affiliation(s)
- Ruth Mokgokong
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| | - Shanshan Wang
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| | - Caroline J. Taylor
- O’Brien Institute and Department of Surgery, University of Melbourne, St. Vincent’s Hospital, 42 Fitzroy Street, Fitzroy, Melbourne, VIC 3065 Australia
- Faculty of Health Sciences, Australian Catholic University, Melbourne, VIC 3065 Australia
| | - Margery A. Barrand
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| | - Stephen B. Hladky
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
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Zöllner JP, Hattingen E, Singer OC, Pilatus U. Changes of pH and energy state in subacute human ischemia assessed by multinuclear magnetic resonance spectroscopy. Stroke 2014; 46:441-6. [PMID: 25503553 DOI: 10.1161/strokeaha.114.007896] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE In vivo changes in tissue pH and energy metabolism are key to understanding stroke pathophysiology. Our goal was to study pH changes in subacute ischemic stroke and their relation to energy metabolism, which, unlike acidosis in acute stroke, are not yet well understood. METHODS We measured tissue pH and phospholipid as well as cell energy markers, including creatine, phosphocreatine, and N-acetyl-aspartate in subacute stroke with combined (1)H and (31)P magnetic resonance spectroscopy. We included 19 patients with first-ever ischemic stroke (mean time after stroke, 6 days). We then compared metabolite concentrations in the ischemic tissue to contralateral (healthy) tissue using multivariate ANOVA to assess significant differences in metabolite levels between both tissue compartments. RESULTS In subacute stroke, a tissue fraction with significantly increased tissue pH was observed as compared with healthy contralateral tissue (pH, 7.09 versus 7.03; P=0.002) concurrent with splitting of the pH signal with 1 peak being more alkalotic. Furthermore, only a moderate decrease of energy-rich metabolites (phosphocreatine reduced by 17%, ATP reduced by 19%) was present, whereas total creatine was reduced by 51%. CONCLUSIONS The finding of an alkalotic pH split in subacute ischemia is unprecedented. The pH split and only incomplete energy loss in subacute stroke suggest 2 differently viable cellular moieties, best explained by active compensatory mechanisms after acute cerebral ischemia.
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Affiliation(s)
- Johann Philipp Zöllner
- From the Department of Neurology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany (J.P.Z., O.C.S) and Institute of Neuroradiology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany (E.H., U.P.)
| | - Elke Hattingen
- From the Department of Neurology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany (J.P.Z., O.C.S) and Institute of Neuroradiology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany (E.H., U.P.)
| | - Oliver C Singer
- From the Department of Neurology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany (J.P.Z., O.C.S) and Institute of Neuroradiology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany (E.H., U.P.).
| | - Ulrich Pilatus
- From the Department of Neurology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany (J.P.Z., O.C.S) and Institute of Neuroradiology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany (E.H., U.P.)
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45
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Inhibition of brain swelling after ischemia-reperfusion by β-adrenergic antagonists: correlation with increased K+ and decreased Ca2+ concentrations in extracellular fluid. BIOMED RESEARCH INTERNATIONAL 2014; 2014:873590. [PMID: 25478577 PMCID: PMC4247955 DOI: 10.1155/2014/873590] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 09/03/2014] [Accepted: 09/10/2014] [Indexed: 12/11/2022]
Abstract
Infarct size and brain edema following ischemia/reperfusion are reduced by inhibitors of the Na+, K+, 2Cl−, and water cotransporter NKCC1 and by β1-adrenoceptor antagonists. NKCC1 is a secondary active transporter, mainly localized in astrocytes, driven by transmembrane Na+/K+ gradients generated by the Na+,K+-ATPase. The astrocytic Na+,K+-ATPase is stimulated by small increases in extracellular K+ concentration and by the β-adrenergic agonist isoproterenol. Larger K+ increases, as occurring during ischemia, also stimulate NKCC1, creating cell swelling. This study showed no edema after 3 hr medial cerebral artery occlusion but pronounced edema after 8 hr reperfusion. The edema was abolished by inhibitors of specifically β1-adrenergic pathways, indicating failure of K+-mediated, but not β1-adrenoceptor-mediated, stimulation of Na+,K+-ATPase/NKCC1 transport during reoxygenation. Ninety percent reduction of extracellular Ca2+ concentration occurs in ischemia. Ca2+ omission abolished K+ uptake in normoxic cultures of astrocytes after addition of 5 mM KCl. A large decrease in ouabain potency on K+ uptake in cultured astrocytes was also demonstrated in Ca2+-depleted media, and endogenous ouabains are needed for astrocytic K+ uptake. Thus, among the ionic changes induced by ischemia, the decrease in extracellular Ca2+ causes failure of the high-K+-stimulated Na+,K+-ATPase/NKCC1 ion/water uptake, making β1-adrenergic activation the only stimulus and its inhibition effective against edema.
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Kikuchi E, Mori T, Zeniya M, Isobe K, Ishigami-Yuasa M, Fujii S, Kagechika H, Ishihara T, Mizushima T, Sasaki S, Sohara E, Rai T, Uchida S. Discovery of Novel SPAK Inhibitors That Block WNK Kinase Signaling to Cation Chloride Transporters. J Am Soc Nephrol 2014; 26:1525-36. [PMID: 25377078 DOI: 10.1681/asn.2014060560] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/20/2014] [Indexed: 12/21/2022] Open
Abstract
Upon activation by with-no-lysine kinases, STE20/SPS1-related proline-alanine-rich protein kinase (SPAK) phosphorylates and activates SLC12A transporters such as the Na(+)-Cl(-) cotransporter (NCC) and Na(+)-K(+)-2Cl(-) cotransporter type 1 (NKCC1) and type 2 (NKCC2); these transporters have important roles in regulating BP through NaCl reabsorption and vasoconstriction. SPAK knockout mice are viable and display hypotension with decreased activity (phosphorylation) of NCC and NKCC1 in the kidneys and aorta, respectively. Therefore, agents that inhibit SPAK activity could be a new class of antihypertensive drugs with dual actions (i.e., NaCl diuresis and vasodilation). In this study, we developed a new ELISA-based screening system to find novel SPAK inhibitors and screened >20,000 small-molecule compounds. Furthermore, we used a drug repositioning strategy to identify existing drugs that inhibit SPAK activity. As a result, we discovered one small-molecule compound (Stock 1S-14279) and an antiparasitic agent (Closantel) that inhibited SPAK-regulated phosphorylation and activation of NCC and NKCC1 in vitro and in mice. Notably, these compounds had structural similarity and inhibited SPAK in an ATP-insensitive manner. We propose that the two compounds found in this study may have great potential as novel antihypertensive drugs.
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Affiliation(s)
- Eriko Kikuchi
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Takayasu Mori
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Moko Zeniya
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Kiyoshi Isobe
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | | | - Shinya Fujii
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan; and
| | - Hiroyuki Kagechika
- Chemical Biology Screening Center, and Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan; and
| | - Tomoaki Ishihara
- Department of Analytical Chemistry, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Tohru Mizushima
- Department of Analytical Chemistry, Faculty of Pharmacy, Keio University, Tokyo, Japan
| | - Sei Sasaki
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Tatemitsu Rai
- Department of Nephrology, Graduate School of Medical and Dental Sciences
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences,
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Hertz L, Xu J, Chen Y, Gibbs ME, Du T, Hertz L, Xu J, Chen Y, Gibbs ME, Du T. Antagonists of the Vasopressin V1 Receptor and of the β(1)-Adrenoceptor Inhibit Cytotoxic Brain Edema in Stroke by Effects on Astrocytes - but the Mechanisms Differ. Curr Neuropharmacol 2014; 12:308-23. [PMID: 25342939 PMCID: PMC4207071 DOI: 10.2174/1570159x12666140828222723] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 06/13/2014] [Accepted: 06/20/2014] [Indexed: 01/16/2023] Open
Abstract
Brain edema is a serious complication in ischemic stroke because even relatively small changes in brain volume can compromise cerebral blood flow or result in compression of vital brain structures on account of the fixed volume of the rigid skull. Literature data indicate that administration of either antagonists of the V1 vasopressin (AVP) receptor or the β1-adrenergic receptor are able to reduce edema or infarct size when administered after the onset of ischemia, a key advantage for possible clinical use. The present review discusses possible mechanisms, focusing on the role of NKCC1, an astrocytic cotransporter of Na(+), K(+), 2Cl(-) and water and its activation by highly increased extracellular K(+) concentrations in the development of cytotoxic cell swelling. However, it also mentions that due to a 3/2 ratio between Na(+) release and K(+) uptake by the Na(+),K(+)-ATPase driving NKCC1 brain extracellular fluid can become hypertonic, which may facilitate water entry across the blood-brain barrier, essential for development of edema. It shows that brain edema does not develop until during reperfusion, which can be explained by lack of metabolic energy during ischemia. V1 antagonists are likely to protect against cytotoxic edema formation by inhibiting AVP enhancement of NKCC1-mediated uptake of ions and water, whereas β1-adrenergic antagonists prevent edema formation because β1-adrenergic stimulation alone is responsible for stimulation of the Na(+),K(+)-ATPase driving NKCC1, first and foremost due to decrease in extracellular Ca(2+) concentration. Inhibition of NKCC1 also has adverse effects, e.g. on memory and the treatment should probably be of shortest possible duration.
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Affiliation(s)
- Leif Hertz
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Junnan Xu
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Ye Chen
- Henry M. Jackson Foundation 6720A Rockledge Dr #100, Bethesda MD 20817, USA
| | - Marie E Gibbs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Parkville, VIC, Australia
| | - Ting Du
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Leif Hertz
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Junnan Xu
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
| | - Ye Chen
- Henry M. Jackson Foundation 6720A Rockledge Dr #100, Bethesda MD 20817, USA
| | - Marie E Gibbs
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University Parkville, VIC, Australia
| | - Ting Du
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, P.R. China
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Blood-brain barrier Na transporters in ischemic stroke. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 71:113-46. [PMID: 25307215 DOI: 10.1016/bs.apha.2014.06.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Blood-brain barrier (BBB) endothelial cells form a barrier that is highly restrictive to passage of solutes between blood and brain. Many BBB transport mechanisms have been described that mediate transcellular movement of solutes across the barrier either into or out of the brain. One class of BBB transporters that is all too often overlooked is that of the ion transporters. The BBB has a rich array of ion transporters and channels that carry Na, K, Cl, HCO3, Ca, and other ions. Many of these are asymmetrically distributed between the luminal and abluminal membranes, giving BBB endothelial cells the ability to perform vectorial transport of ions across the barrier between blood and brain. In this manner, the BBB performs the important function of regulating the volume and composition of brain interstitial fluid. Through functional coupling of luminal and abluminal transporters and channels, the BBB carries Na, Cl, and other ions from blood into brain, producing up to 30% of brain interstitial fluid in healthy brain. During ischemic stroke cerebral edema forms by processes involving increased activity of BBB luminal Na transporters, resulting in "hypersecretion" of Na, Cl, and water into the brain interstitium. This review discusses the roles of luminal BBB Na transporters in edema formation in stroke, with an emphasis on Na-K-Cl cotransport and Na/H exchange. Evidence that these transporters provide effective therapeutic targets for reduction of edema in stroke is also discussed, as are recent findings regarding signaling pathways responsible for ischemia stimulation of the BBB Na transporters.
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Song D, Du T. Ammonium activates ouabain-activated signalling pathway in astrocytes: therapeutic potential of ouabain antagonist. Curr Neuropharmacol 2014; 12:334-41. [PMID: 25342941 PMCID: PMC4207073 DOI: 10.2174/1570159x12666140828222115] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 06/18/2014] [Accepted: 06/25/2014] [Indexed: 01/16/2023] Open
Abstract
The causal role of ammonium in hepatic encephalopathy was identified in 1930s. Astroglial cells are primary cellular elements of hepatic encephalopathy which conceptually, can be considered a toxic astrogliopathology. Previously we have reported that acute exposure to ammonium activated ouabain/Na,K-ATPase signalling pathway, which includes Src, EGF receptor, Raf, Ras, MEK and ERK1/2. Chronic incubation of astrocytes with ammonium increased production of endogenous ouabain-like compound. Ouabain antagonist canrenone abolished effects of ammonium on astrocytic swelling, ROS production, and upregulation of gene expression and function of TRPC1 and Cav1.2. However, ammonium induces multiple pathological modifications in astrocytes, and some of them may be not related to this signalling pathway. In this review, we focus on the effect of ammonium on ouabain/Na,K-ATPase signalling pathway and its involvement in ammonium-induced ROS production, cell swelling and aberration of Ca(2+) signals in astrocytes. We also briefly discuss Na,K-ATPase, EGF receptor, endogenous ouabain and ouabain antagonist.
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Affiliation(s)
- Dan Song
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, Shenyang, P. R. China
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Hertz L, Peng L, Song D. Ammonia, like K(+), stimulates the Na(+), K(+), 2 Cl(-) cotransporter NKCC1 and the Na(+),K(+)-ATPase and interacts with endogenous ouabain in astrocytes. Neurochem Res 2014; 40:241-57. [PMID: 24929663 DOI: 10.1007/s11064-014-1352-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 05/31/2014] [Accepted: 06/03/2014] [Indexed: 12/12/2022]
Abstract
Brain edema during hepatic encephalopathy or acute liver failure as well as following brain ischemia has a multifactorial etiology, but it is a dangerous and occasionally life-threatening complication because the brain is enclosed in the rigid skull. During ischemia the extracellular K(+) concentration increases to very high levels, which when energy becomes available during reperfusion stimulate NKCC1, a cotransporter driven by the transmembrane ion gradients established by the Na(+),K(+)-ATPase and accumulating Na(+), K(+) and 2 Cl(-) together with water. This induces pronounced astrocytic swelling under pathologic conditions, but NKCC1 is probably also activated, although to a lesser extent, during normal brain function. Redistribution of ions and water between extra- and intracellular phases does not create brain edema, which in addition requires uptake across the blood-brain barrier. During hepatic encephalopathy and acute liver failure a crucial factor is the close resemblance between K(+) and NH4(+) in their effects not only on NKCC1 and Na(+),K(+)-ATPase but also on Na(+),K(+)-ATPase-induced signaling by endogenous ouabains. These in turn activate production of ROS and nitrosactive agents which slowly sensitize NKCC1, explaining why cell swelling and brain edema generally are delayed under hyperammonemic conditions, although very high ammonia concentrations can cause immediate NKCC1 activation.
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Affiliation(s)
- Leif Hertz
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 92 Beier Road, Heping District, Shenyang, People's Republic of China
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