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Lee J, Shin I. Nuclear Chloride Ion-Selective Fluorescent Probe and Its Biological Applications. ACS Sens 2024. [PMID: 39054598 DOI: 10.1021/acssensors.4c00868] [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: 07/27/2024]
Abstract
Owing to the biological significance of Cl- in cells, several chemical fluorescent probes and biosensors have been constructed to monitor this anion in the cytosol and subcellular organelles. However, a fluorescent probe for the selective detection of nuclear Cl- has not been described thus far. In the current study, we developed the first nuclear Cl--selective biosensor, Cl-YFP-NLS, whose fluorescence was effectively quenched by this anion, and demonstrated that it is an efficient and powerful tool for determining the levels of nuclear Cl-. The results of cell studies using Cl-YFP-NLS as the probe suggested that the level of Cl- in the nucleus is lower than that in the cytosol. In addition, Cl-YFP-NLS along with lysosomal (Lyso-MQAE) and mitochondrial Cl--selective fluorescent probes (Mito-MQAE) were utilized to determine the effects of various substances on the levels of Cl- in subcellular organelles. The results showed that lysosomotropic agents decrease the lysosomal Cl- concentration and increase the levels of mitochondrial and nuclear Cl-. Also, observations suggested that substances capable of inducing mitochondrial outer membrane permeabilization without inducing lysosomal membrane permeabilization increase mitochondrial and nuclear Cl- concentrations but they do not affect the level of lysosomal Cl-. Moreover, a substance directly disrupting nuclear pore complexes increased the level of nuclear Cl- and did not change the levels of lysosomal and mitochondrial Cl-. Finally, nucleus-affecting substances that cause deoxyribonucleic acid damage and activate p53 and Bax increased the levels of mitochondrial and nuclear Cl- without influencing the level of lysosomal Cl-.
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Affiliation(s)
- Jongwon Lee
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Injae Shin
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
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2
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Normoyle KP, Lillis KP, Staley KJ. Synthesis and Characterization of a Novel Concentration-Independent Fluorescent Chloride Indicator, ABP-Dextran, Optimized for Extracellular Chloride Measurement. Biomolecules 2024; 14:77. [PMID: 38254677 PMCID: PMC10813347 DOI: 10.3390/biom14010077] [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: 10/16/2023] [Revised: 12/20/2023] [Accepted: 12/22/2023] [Indexed: 01/24/2024] Open
Abstract
GABA, the primary inhibitory neurotransmitter, stimulates GABAA receptors (GABAARs) to increase the chloride conductance of the cytosolic membrane. The driving forces for membrane chloride currents are determined by the local differences between intracellular and extracellular chloride concentrations (Cli and Clo, respectively). While several strategies exist for the measurement of Cli, the field lacks tools for non-invasive measurement of Clo. We present the design and development of a fluorescent lifetime imaging (FLIM)-compatible small molecule, N(4-aminobutyl)phenanthridiunium (ABP) with the brightness, spectral features, sensitivity to chloride, and selectivity versus other anions to serve as a useful probe of Clo. ABP can be conjugated to dextran to ensure extracellular compartmentalization, and a second chloride-insensitive counter-label can be added for ratiometric imaging. We validate the utility of this novel sensor series in two sensor concentration-independent modes: FLIM or ratiometric intensity-based imaging.
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Affiliation(s)
- Kieran P. Normoyle
- Massachusetts General Hospital, Department of Neurology, 55 Fruit Street, Boston, MA 02114, USA; (K.P.N.); (K.P.L.)
- Harvard Medical School, Department of Neurology, 77 Louis Pasteur Avenue, Boston, MA 02115, USA
| | - Kyle P. Lillis
- Massachusetts General Hospital, Department of Neurology, 55 Fruit Street, Boston, MA 02114, USA; (K.P.N.); (K.P.L.)
- Harvard Medical School, Department of Neurology, 77 Louis Pasteur Avenue, Boston, MA 02115, USA
| | - Kevin J. Staley
- Massachusetts General Hospital, Department of Neurology, 55 Fruit Street, Boston, MA 02114, USA; (K.P.N.); (K.P.L.)
- Harvard Medical School, Department of Neurology, 77 Louis Pasteur Avenue, Boston, MA 02115, USA
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3
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Trzeciak AJ, Rojas WS, Liu ZL, Krebs AS, Wang Z, Saavedra PHV, Miranda IC, Lipshutz A, Xie J, Huang CL, Overholtzer M, Glickman MS, Parkhurst CN, Vierbuchen T, Lucas CD, Perry JSA. WNK1 enforces macrophage lineage fidelity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.26.538482. [PMID: 37383948 PMCID: PMC10299535 DOI: 10.1101/2023.04.26.538482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/30/2023]
Abstract
The appropriate development of macrophages, the body's professional phagocyte, is essential for organismal development, especially in mammals. This dependence is exemplified by the observation that loss-of-function mutations in colony stimulating factor 1 receptor (CSF1R) results in multiple tissue abnormalities owing to an absence of macrophages. Despite this importance, little is known about the molecular and cell biological regulation of macrophage development. Here, we report the surprising finding that the chloride-sensing kinase With-no-lysine 1 (WNK1) is required for development of tissue-resident macrophages (TRMs). Myeloid-specific deletion of Wnk1 resulted in a dramatic loss of TRMs, disrupted organ development, systemic neutrophilia, and mortality between 3 and 4 weeks of age. Strikingly, we found that myeloid progenitors or precursors lacking WNK1 not only failed to differentiate into macrophages, but instead differentiated into neutrophils. Mechanistically, the cognate CSF1R cytokine macrophage-colony stimulating factor (M-CSF) stimulates macropinocytosis by both mouse and human myeloid progenitors and precursor cells. Macropinocytosis, in turn, induces chloride flux and WNK1 phosphorylation. Importantly, blocking macropinocytosis, perturbing chloride flux during macropinocytosis, and inhibiting WNK1 chloride-sensing activity each skewed myeloid progenitor differentiation from macrophages into neutrophils. Thus, we have elucidated a role for WNK1 during macropinocytosis and discovered a novel function of macropinocytosis in myeloid progenitors and precursor cells to ensure macrophage lineage fidelity. Highlights Myeloid-specific WNK1 loss causes failed macrophage development and premature deathM-CSF-stimulated myeloid progenitors and precursors become neutrophils instead of macrophagesM-CSF induces macropinocytosis by myeloid progenitors, which depends on WNK1Macropinocytosis enforces macrophage lineage commitment.
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Pressey JC, de Saint-Rome M, Raveendran VA, Woodin MA. Chloride transporters controlling neuronal excitability. Physiol Rev 2023; 103:1095-1135. [PMID: 36302178 DOI: 10.1152/physrev.00025.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Synaptic inhibition plays a crucial role in regulating neuronal excitability, which is the foundation of nervous system function. This inhibition is largely mediated by the neurotransmitters GABA and glycine that activate Cl--permeable ion channels, which means that the strength of inhibition depends on the Cl- gradient across the membrane. In neurons, the Cl- gradient is primarily mediated by two secondarily active cation-chloride cotransporters (CCCs), NKCC1 and KCC2. CCC-mediated regulation of the neuronal Cl- gradient is critical for healthy brain function, as dysregulation of CCCs has emerged as a key mechanism underlying neurological disorders including epilepsy, neuropathic pain, and autism spectrum disorder. This review begins with an overview of neuronal chloride transporters before explaining the dependent relationship between these CCCs, Cl- regulation, and inhibitory synaptic transmission. We then discuss the evidence for how CCCs can be regulated, including by activity and their protein interactions, which underlie inhibitory synaptic plasticity. For readers who may be interested in conducting experiments on CCCs and neuronal excitability, we have included a section on techniques for estimating and recording intracellular Cl-, including their advantages and limitations. Although the focus of this review is on neurons, we also examine how Cl- is regulated in glial cells, which in turn regulate neuronal excitability through the tight relationship between this nonneuronal cell type and synapses. Finally, we discuss the relatively extensive and growing literature on how CCC-mediated neuronal excitability contributes to neurological disorders.
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Affiliation(s)
- Jessica C Pressey
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Miranda de Saint-Rome
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Vineeth A Raveendran
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Melanie A Woodin
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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Using SuperClomeleon to Measure Changes in Intracellular Chloride during Development and after Early Life Stress. eNeuro 2022; 9:ENEURO.0416-22.2022. [PMID: 36635254 PMCID: PMC9797207 DOI: 10.1523/eneuro.0416-22.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/25/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Intraneuronal chloride concentrations ([Cl-]i) decrease during development resulting in a shift from depolarizing to hyperpolarizing GABA responses via chloride-permeable GABAA receptors. This GABA shift plays a pivotal role in postnatal brain development, and can be strongly influenced by early life experience. Here, we assessed the applicability of the recently developed fluorescent SuperClomeleon (SClm) sensor to examine changes in [Cl-]i using two-photon microscopy in brain slices. We used SClm mice of both sexes to monitor the developmental decrease in neuronal chloride levels in organotypic hippocampal cultures. We could discern a clear reduction in [Cl-]i between day in vitro (DIV)3 and DIV9 (equivalent to the second postnatal week in vivo) and a further decrease in some cells until DIV22. In addition, we assessed alterations in [Cl-]i in the medial prefrontal cortex (mPFC) of postnatal day (P)9 male SClm mouse pups after early life stress (ELS). ELS was induced by limiting nesting material between P2 and P9. ELS induced a shift toward higher (i.e., immature) chloride levels in layer 2/3 cells in the mPFC. Although conversion from SClm fluorescence to absolute chloride concentrations proved difficult, our study underscores that the SClm sensor is a powerful tool to measure physiological changes in [Cl-]i in brain slices.
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Biophysical quantification of unitary solute and solvent permeabilities to enable translation to membrane science. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.121308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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KCC2 drives chloride microdomain formation in dendritic blebbing. Cell Rep 2022; 41:111556. [DOI: 10.1016/j.celrep.2022.111556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 06/23/2022] [Accepted: 09/30/2022] [Indexed: 11/22/2022] Open
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Wang D, Xia T, Wang Y, Chen Y, Zhang C, Murray W, Schultz AT, Liu Z, Yang J. Citrate-based fluorometric sensor for multi-halide sensing. SMART MATERIALS IN MEDICINE 2022; 3:374-381. [PMID: 38031570 PMCID: PMC10686323 DOI: 10.1016/j.smaim.2022.05.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Halides play important roles in human health and environmental monitoring. However, different halides interfere with each other in current measurement methods. Simultaneous sensing of multiple halides in a fast and low-cost manner remains a challenge. Here, we report a fluorometric multi-halide sensing method by using a single citrate-based fluorophore, CA-Cys, on a custom-made portable device. The fluorescence emitted by CA-Cys is quenched due to the dynamic quenching of halide ions; the sensitivities vary from halide types and pH, providing the capability to obtain multiple Stern-Volmer equations at various pH values. The concentration of each halide can then be obtained by solving the resultant set of equations. A mM scale detection limit is demonstrated, which is suitable for halide wastewater monitoring. A proof-of-concept smartphone-based portable device is also fabricated and tested. The results from the fluorometer and portable device indicated that our multi-halide system is promising for real-world multi-halide sensing applications. This work represents a new direction in developing portable, low-cost, and simultaneous multi-halide sensing technologies.
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Affiliation(s)
- Dingbowen Wang
- Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Tunan Xia
- Department of Electrical Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Yuqi Wang
- Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Yizhu Chen
- Department of Electrical Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Chenji Zhang
- Department of Electrical Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - William Murray
- Department of Electrical Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Adam Thomas Schultz
- Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Zhiwen Liu
- Department of Electrical Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Jian Yang
- Department of Biomedical Engineering, Materials Research Institute, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
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9
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Wu SY, Shen Y, Shkolnikov I, Campbell RE. Fluorescent Indicators For Biological Imaging of Monatomic Ions. Front Cell Dev Biol 2022; 10:885440. [PMID: 35573682 PMCID: PMC9093666 DOI: 10.3389/fcell.2022.885440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Monatomic ions play critical biological roles including maintaining the cellular osmotic pressure, transmitting signals, and catalyzing redox reactions as cofactors in enzymes. The ability to visualize monatomic ion concentration, and dynamic changes in the concentration, is essential to understanding their many biological functions. A growing number of genetically encodable and synthetic indicators enable the visualization and detection of monatomic ions in biological systems. With this review, we aim to provide a survey of the current landscape of reported indicators. We hope this review will be a useful guide to researchers who are interested in using indicators for biological applications and to tool developers seeking opportunities to create new and improved indicators.
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Affiliation(s)
- Sheng-Yi Wu
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Yi Shen
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
| | - Irene Shkolnikov
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
- Department of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Robert E. Campbell
- Department of Chemistry, University of Alberta, Edmonton, AB, Canada
- Department of Chemistry, The University of Tokyo, Tokyo, Japan
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10
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Premkumar A, Javed MT, Pawlowski K, Lindberg SM. Silicate Inhibits the Cytosolic Influx of Chloride in Protoplasts of Wheat and Affects the Chloride Transporters, TaCLC1 and TaNPF2.4/2.5. PLANTS 2022; 11:plants11091162. [PMID: 35567163 PMCID: PMC9102027 DOI: 10.3390/plants11091162] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 04/01/2022] [Accepted: 04/19/2022] [Indexed: 11/23/2022]
Abstract
Chloride is an essential nutrient for plants, but high concentrations can be harmful. Silicon ameliorates both abiotic and biotic stresses in plants, but it is unknown if it can prevent cellular increase of chloride. Therefore, we investigated the influx of Cl− ions in two wheat cultivars different in salt sensitivity, by epifluorescence microscopy and a highly Cl−-sensitive dye, MQAE, N-[ethoxycarbonylmethyl]-6-methoxy-quinolinium bromide, in absence and presence of potassium silicate, K2SiO3. The Cl−-influx was higher in the salt-sensitive cv. Vinjett, than in the salt-tolerant cv. S-24, and silicate pre-treatment of protoplasts inhibited the Cl−-influx in both cultivars, but more in the sensitive cv. Vinjett. To investigate if the Cl−-transporters TaCLC1 and TaNPF2.4/2.5 are affected by silicate, expression analyses by RT-qPCR were undertaken of TaCLC1 and TaNPF 2.4/2.5 transcripts in the absence and presence of 100 mM NaCl, with and without the presence of K2SiO3. The results show that both transporter genes were expressed in roots and shoots of wheat seedlings, but their expressions were differently affected by silicate. The TaNPF2.4/2.5 expression in leaves was markedly depressed by silicate. These findings demonstrate that less chloride accumulates in the cytosol of leaf mesophyll by Si treatment and increases salt tolerance.
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Affiliation(s)
| | - Muhammad Tariq Javed
- Department of Botany, Faculty of Life Sciences, Government College University, Faisalabad 38000, Pakistan;
| | - Katharina Pawlowski
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-11418 Stockholm, Sweden;
| | - Sylvia M. Lindberg
- Department of Ecology, Environment and Plant Sciences, Stockholm University, SE-11418 Stockholm, Sweden;
- Correspondence:
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11
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Lopes J, Machado A, Batista A, Araujo P, Barbosa Neto N. Protonation, exciplex, and evidence of aggregate formation in meso-tetra(4-pyridyl) porphyrin triggered by excited-state absorption. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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12
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Abstract
Chloride transport across cell membranes is broadly involved in epithelial fluid transport, cell volume and pH regulation, muscle contraction, membrane excitability, and organellar acidification. The human genome encodes at least 53 chloride-transporting proteins with expression in cell plasma or intracellular membranes, which include chloride channels, exchangers, and cotransporters, some having broad anion specificity. Loss-of-function mutations in chloride transporters cause a wide variety of human diseases, including cystic fibrosis, secretory diarrhea, kidney stones, salt-wasting nephropathy, myotonia, osteopetrosis, hearing loss, and goiter. Although impactful advances have been made in the past decade in drug treatment of cystic fibrosis using small molecule modulators of the defective cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel, other chloride channels and solute carrier proteins (SLCs) represent relatively underexplored target classes for drug discovery. New opportunities have emerged for the development of chloride transport modulators as potential therapeutics for secretory diarrheas, constipation, dry eye disorders, kidney stones, polycystic kidney disease, hypertension, and osteoporosis. Approaches to chloride transport-targeted drug discovery are reviewed herein, with focus on chloride channel and exchanger classes in which recent preclinical advances have been made in the identification of small molecule modulators and in proof of concept testing in experimental animal models.
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Affiliation(s)
- Alan S Verkman
- Department of Medicine, University of California, San Francisco, California.,Department of Physiology, University of California, San Francisco, California
| | - Luis J V Galietta
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
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13
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Yang J, Yu G, Sessler JL, Shin I, Gale PA, Huang F. Artificial transmembrane ion transporters as potential therapeutics. Chem 2021. [DOI: 10.1016/j.chempr.2021.10.028] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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14
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Yamagishi A, Ito F, Nakamura C. Study on Cancer Cell Invasiveness via Application of Mechanical Force to Induce Chloride Ion Efflux. Anal Chem 2021; 93:9032-9035. [PMID: 34152726 DOI: 10.1021/acs.analchem.1c01589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Chloride channels regulate cell volume by an efflux of chloride ions in response to osmotic stresses. These have been shown to play a role in cancer invasion. However, their function in cancer metastasis remains unclear. As the internal environment of the human body is rarely exposed to osmotic stress, we presumed that Cl- efflux in cancer cells is induced by mechanical stress caused by their crowded environment and invasion of their narrow interstitial spaces. In this study, we recruited atomic force microscopy to apply mechanical stress to mouse or human breast cancer cells with varying degrees of malignancy and examined their Cl- efflux by N-ethoxycarbonylmethyl-6-methoxyquinolinium bromide (MQAE), which is quenched via collision with Cl- ions. We found that intracellular MQAE fluorescence intensity increased immediately after cell compression, demonstrating induction of Cl- efflux by mechanical force. Furthermore, Cl- efflux ability showed correlation with the cancer metastatic potential. These results suggested that mechanical stress induced Cl- efflux may serve as a potential reporter for estimating the invasion ability of cancer cells.
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Affiliation(s)
- Ayana Yamagishi
- AIST-INDIA DAILAB, Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 5 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
| | - Fumie Ito
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
| | - Chikashi Nakamura
- AIST-INDIA DAILAB, Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 5 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.,Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 2-24-16 Naka-cho, Koganei, Tokyo 184-8588, Japan
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15
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Rahmati N, Normoyle KP, Glykys J, Dzhala VI, Lillis KP, Kahle KT, Raiyyani R, Jacob T, Staley KJ. Unique Actions of GABA Arising from Cytoplasmic Chloride Microdomains. J Neurosci 2021; 41:4957-4975. [PMID: 33903223 PMCID: PMC8197632 DOI: 10.1523/jneurosci.3175-20.2021] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/10/2021] [Accepted: 04/10/2021] [Indexed: 12/21/2022] Open
Abstract
Developmental, cellular, and subcellular variations in the direction of neuronal Cl- currents elicited by GABAA receptor activation have been frequently reported. We found a corresponding variance in the GABAA receptor reversal potential (EGABA) for synapses originating from individual interneurons onto a single pyramidal cell. These findings suggest a similar heterogeneity in the cytoplasmic intracellular concentration of chloride ([Cl-]i) in individual dendrites. We determined [Cl-]i in the murine hippocampus and cerebral cortex of both sexes by (1) two-photon imaging of the Cl--sensitive, ratiometric fluorescent protein SuperClomeleon; (2) Fluorescence Lifetime IMaging (FLIM) of the Cl--sensitive fluorophore MEQ (6-methoxy-N-ethylquinolinium); and (3) electrophysiological measurements of EGABA by pressure application of GABA and RuBi-GABA uncaging. Fluorometric and electrophysiological estimates of local [Cl-]i were highly correlated. [Cl-]i microdomains persisted after pharmacological inhibition of cation-chloride cotransporters, but were progressively modified after inhibiting the polymerization of the anionic biopolymer actin. These methods collectively demonstrated stable [Cl-]i microdomains in individual neurons in vitro and in vivo and the role of immobile anions in its stability. Our results highlight the existence of functionally significant neuronal Cl- microdomains that modify the impact of GABAergic inputs.SIGNIFICANCE STATEMENT Microdomains of varying chloride concentrations in the neuronal cytoplasm are a predictable consequence of the inhomogeneous distribution of anionic polymers such as actin, tubulin, and nucleic acids. Here, we demonstrate the existence and stability of these microdomains, as well as the consequence for GABAergic synaptic signaling: each interneuron produces a postsynaptic GABAA response with a unique reversal potential. In individual hippocampal pyramidal cells, the range of GABAA reversal potentials evoked by stimulating different interneurons was >20 mV. Some interneurons generated postsynaptic responses in pyramidal cells that reversed at potentials beyond what would be considered purely inhibitory. Cytoplasmic chloride microdomains enable each pyramidal cell to maintain a compendium of unique postsynaptic responses to the activity of individual interneurons.
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Affiliation(s)
- Negah Rahmati
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kieran P Normoyle
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Joseph Glykys
- Department of Pediatrics and Neurology, Iowa Neuroscience Institute, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Volodymyr I Dzhala
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kyle P Lillis
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kristopher T Kahle
- Departments of Neurosurgery, Pediatrics, and Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut 06510
| | - Rehan Raiyyani
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Theju Jacob
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
| | - Kevin J Staley
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Boston, Massachusetts 02114
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16
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LRRC8A-containing chloride channel is crucial for cell volume recovery and survival under hypertonic conditions. Proc Natl Acad Sci U S A 2021; 118:2025013118. [PMID: 34083438 PMCID: PMC8201826 DOI: 10.1073/pnas.2025013118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Rapid regulatory volume increase (RVI) is important for cell survival under hypertonic conditions. RVI is driven by Cl− uptake via the Na–K–Cl cotransporter (NKCC), which is activated by WNK kinases following a reduction in intracellular [Cl−]. However, how intracellular [Cl−] is regulated to modulate the WNK–NKCC axis and engage a protective RVI remains unknown. Our work reveals that LRRC8A-containing chloride channel is a key protective factor against hypertonic shocks. Considering that LRRC8A (SWELL1) is typically activated by low ionic strength under hypotonic stress, our results posed another interesting question: what activates this chloride channel under hypertonic stress? We demonstrated that, upon hyperosmotic activation, the p38-MSK1 pathway gates LRRC8A-containing chloride channel to facilitate activation of WNK–NKCC and an effective RVI. Regulation of cell volume is essential for tissue homeostasis and cell viability. In response to hypertonic stress, cells need rapid electrolyte influx to compensate water loss and to prevent cell death in a process known as regulatory volume increase (RVI). However, the molecular component able to trigger such a process was unknown to date. Using a genome-wide CRISPR/Cas9 screen, we identified LRRC8A, which encodes a chloride channel subunit, as the gene most associated with cell survival under hypertonic conditions. Hypertonicity activates the p38 stress-activated protein kinase pathway and its downstream MSK1 kinase, which phosphorylates and activates LRRC8A. LRRC8A-mediated Cl− efflux facilitates activation of the with-no-lysine (WNK) kinase pathway, which in turn, promotes electrolyte influx via Na+/K+/2Cl− cotransporter (NKCC) and RVI under hypertonic stress. LRRC8A-S217A mutation impairs channel activation by MSK1, resulting in reduced RVI and cell survival. In summary, LRRC8A is key to bidirectional osmotic stress responses and cell survival under hypertonic conditions.
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17
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Parrini M, Naskar S, Alberti M, Colombi I, Morelli G, Rocchi A, Nanni M, Piccardi F, Charles S, Ronzitti G, Mingozzi F, Contestabile A, Cancedda L. Restoring neuronal chloride homeostasis with anti-NKCC1 gene therapy rescues cognitive deficits in a mouse model of Down syndrome. Mol Ther 2021; 29:3072-3092. [PMID: 34058387 PMCID: PMC8531145 DOI: 10.1016/j.ymthe.2021.05.023] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 04/27/2021] [Accepted: 05/18/2021] [Indexed: 01/24/2023] Open
Abstract
A common feature of diverse brain disorders is the alteration of GABA-mediated inhibition because of aberrant, intracellular chloride homeostasis induced by changes in the expression and/or function of chloride transporters. Notably, pharmacological inhibition of the chloride importer NKCC1 is able to rescue brain-related core deficits in animal models of these pathologies and in some human clinical studies. Here, we show that reducing NKCC1 expression by RNA interference in the Ts65Dn mouse model of Down syndrome (DS) restores intracellular chloride concentration, efficacy of gamma-aminobutyric acid (GABA)-mediated inhibition, and neuronal network dynamics in vitro and ex vivo. Importantly, adeno-associated virus (AAV)-mediated, neuron-specific NKCC1 knockdown in vivo rescues cognitive deficits in diverse behavioral tasks in Ts65Dn animals. Our results highlight a mechanistic link between NKCC1 expression and behavioral abnormalities in DS mice and establish a molecular target for new therapeutic approaches, including gene therapy, to treat brain disorders characterized by neuronal chloride imbalance.
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Affiliation(s)
- Martina Parrini
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Shovan Naskar
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Micol Alberti
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Ilaria Colombi
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Giovanni Morelli
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Anna Rocchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16132 Genoa, Italy; IRCSS Ospedale Policlinico San Martino, 16132 Genoa, Italy
| | - Marina Nanni
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Federica Piccardi
- Animal Facility, Istituto Italiano di Tecnologia, 16163 Genoa, Italy
| | - Severine Charles
- Genethon, 91000 Evry, France; Paris-Saclay University, University Evry, Inserm, Integrare research unit UMR_S951, 91000 Evry, France
| | - Giuseppe Ronzitti
- Genethon, 91000 Evry, France; Paris-Saclay University, University Evry, Inserm, Integrare research unit UMR_S951, 91000 Evry, France
| | - Federico Mingozzi
- Genethon, 91000 Evry, France; Paris-Saclay University, University Evry, Inserm, Integrare research unit UMR_S951, 91000 Evry, France
| | - Andrea Contestabile
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, 16163 Genoa, Italy.
| | - Laura Cancedda
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia, 16163 Genoa, Italy; Dulbecco Telethon Institute, 00185 Rome, Italy.
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18
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Feroz H, Ferlez B, Oh H, Mohammadiarani H, Ren T, Baker CS, Gajewski JP, Lugar DJ, Gaudana SB, Butler P, Hühn J, Lamping M, Parak WJ, Blatt MR, Kerfeld CA, Smirnoff N, Vashisth H, Golbeck JH, Kumar M. Liposome-based measurement of light-driven chloride transport kinetics of halorhodopsin. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2021; 1863:183637. [PMID: 33930372 DOI: 10.1016/j.bbamem.2021.183637] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 04/14/2021] [Accepted: 04/22/2021] [Indexed: 11/30/2022]
Abstract
We report a simple and direct fluorimetric vesicle-based method for measuring the transport rate of the light-driven ions pumps as specifically applied to the chloride pump, halorhodopsin, from Natronomonas pharaonis (pHR). Previous measurements were cell-based and methods to determine average single channel permeability challenging. We used a water-in-oil emulsion method for directional pHR reconstitution into two different types of vesicles: lipid vesicles and asymmetric lipid-block copolymer vesicles. We then used stopped-flow experiments combined with fluorescence correlation spectroscopy to determine per protein Cl- transport rates. We obtained a Cl- transport rate of 442 (±17.7) Cl-/protein/s in egg phosphatidyl choline (PC) lipid vesicles and 413 (±26) Cl-/protein/s in hybrid block copolymer/lipid (BCP/PC) vesicles with polybutadine-polyethylene oxide (PB12PEO8) on the outer leaflet and PC in the inner leaflet at a photon flux of 1450 photons/protein/s. Normalizing to a per photon basis, this corresponds to 0.30 (±0.07) Cl-/photon and 0.28 (±0.04) Cl-/photon for pure PC and BCP/PC hybrid vesicles respectively, both of which are in agreement with recently reported turnover of ~500 Cl-/protein/s from flash photolysis experiments and with voltage-clamp measurements of 0.35 (±0.16) Cl-/photon in pHR-expressing oocytes as well as with a pHR quantum efficiency of ~30%.
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Affiliation(s)
- Hasin Feroz
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Bryan Ferlez
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Hyeonji Oh
- Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | | | - Tingwei Ren
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Carol S Baker
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - John P Gajewski
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Daniel J Lugar
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Sandeep B Gaudana
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA
| | - Peter Butler
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Jonas Hühn
- Department of Physics and Chemistry, Philipps University of Marburg, Marburg, Germany
| | - Matthias Lamping
- Department of Physics and Chemistry, Philipps University of Marburg, Marburg, Germany
| | - Wolfgang J Parak
- Center of Hybrid Nanostructures (CHyN), Universität Hamburg, Hamburg, Germany
| | - Michael R Blatt
- Laboratory of Plant Physiology and Biophysics, Institute of Molecular Cell and Systems Biology, Bower Building, University of Glasgow, Glasgow G12 8QQ, UK
| | - Cheryl A Kerfeld
- MSU-DOE Plant Research Laboratory and Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA; Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA; Environmental Genomics and Systems Biology and Molecular Biophysics and Integrated Bioimaging Divisions, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | | | - Harish Vashisth
- Department of Chemical Engineering, The University of New Hampshire, Durham, NH, USA
| | - John H Golbeck
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA; Department of Chemistry, The Pennsylvania State University, University Park, PA, USA
| | - Manish Kumar
- Department of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, Austin, TX, USA.
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19
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Delpire E. Advances in the development of novel compounds targeting cation-chloride cotransporter physiology. Am J Physiol Cell Physiol 2021; 320:C324-C340. [PMID: 33356948 PMCID: PMC8294628 DOI: 10.1152/ajpcell.00566.2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 01/05/2023]
Abstract
For about half a century, the pharmacology of electroneutral cation-chloride cotransporters has been dominated by a few drugs that are widely used in clinical medicine. Because these diuretic drugs are so good at what they do, there has been little incentive in expanding their pharmacology. The increasing realization that cation-chloride cotransporters are involved in many other key physiological processes and the knowledge that different tissues express homologous proteins with matching transport functions have rekindled interest in drug discovery. This review summarizes the methods available to assess the function of these transporters and describe the multiple efforts that have made to identify new compounds. We describe multiple screens targeting KCC2 function and one screen designed to find compounds that discriminate between NKCC1 and NKCC2. Two of the KCC2 screens identified new inhibitors that are 3-4 orders of magnitude more potent than furosemide. Additional screens identified compounds that purportedly increase cell surface expression of the cotransporter, as well as several FDA-approved drugs that increase KCC2 transcription and expression. The technical details of each screen biased them toward specific processes in the life cycle of the transporter, making these efforts independent and complementary. In addition, each drug discovery effort contributes to our understanding of the biology of the cotransporters.
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Affiliation(s)
- Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee
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20
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Park SH, Shin I, Kim YH, Shin I. Mitochondrial Cl --Selective Fluorescent Probe for Biological Applications. Anal Chem 2020; 92:12116-12119. [PMID: 32829639 DOI: 10.1021/acs.analchem.0c02658] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Herein we describe the development of the first mitochondrial Cl--selective fluorescent probe, Mito-MQAE, and its applications in biological systems. Fluorescence of Mito-MQAE is insensitive to pH over the physiological pH range and is quenched by Cl- with a Stern-Volmer quenching constant of 201 M-1 at pH 7.0. The results of cell studies using Mito-MQAE show that substances with the ability to disrupt mitochondrial membranes cause increases in the mitochondrial Cl- concentration.
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Affiliation(s)
- Sang-Hyun Park
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Insu Shin
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Young-Hyun Kim
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
| | - Injae Shin
- Department of Chemistry, Yonsei University, Seoul 03722, Republic of Korea
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21
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Drosophila as a model for studying cystic fibrosis pathophysiology of the gastrointestinal system. Proc Natl Acad Sci U S A 2020; 117:10357-10367. [PMID: 32345720 DOI: 10.1073/pnas.1913127117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cystic fibrosis (CF) is a recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The most common symptoms include progressive lung disease and chronic digestive conditions. CF is the first human genetic disease to benefit from having five different species of animal models. Despite the phenotypic differences among the animal models and human CF, these models have provided invaluable insight into understanding disease mechanisms at the organ-system level. Here, we identify a member of the ABCC4 family, CG5789, that has the structural and functional properties expected for encoding the Drosophila equivalent of human CFTR, and thus refer to it as Drosophila CFTR (Dmel\CFTR). We show that knockdown of Dmel\CFTR in the adult intestine disrupts osmotic homeostasis and displays CF-like phenotypes that lead to intestinal stem cell hyperplasia. We also show that expression of wild-type human CFTR, but not mutant variants of CFTR that prevent plasma membrane expression, rescues the mutant phenotypes of Dmel\CFTR Furthermore, we performed RNA sequencing (RNA-Seq)-based transcriptomic analysis using Dmel\CFTR fly intestine and identified a mucin gene, Muc68D, which is required for proper intestinal barrier protection. Altogether, our findings suggest that Drosophila can be a powerful model organism for studying CF pathophysiology.
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22
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Interpreting an apoptotic corpse as anti-inflammatory involves a chloride sensing pathway. Nat Cell Biol 2019; 21:1532-1543. [PMID: 31792382 PMCID: PMC7140761 DOI: 10.1038/s41556-019-0431-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 10/29/2019] [Indexed: 12/11/2022]
Abstract
Apoptotic cell clearance (efferocytosis) elicits an anti-inflammatory response by phagocytes, but the mechanisms that underlie this response are still being defined. Here, we uncover a chloride-sensing signalling pathway that controls both the phagocyte 'appetite' and its anti-inflammatory response. Efferocytosis transcriptionally altered the genes that encode the solute carrier (SLC) proteins SLC12A2 and SLC12A4. Interfering with SLC12A2 expression or function resulted in a significant increase in apoptotic corpse uptake per phagocyte, whereas the loss of SLC12A4 inhibited corpse uptake. In SLC12A2-deficient phagocytes, the canonical anti-inflammatory program was replaced by pro-inflammatory and oxidative-stress-associated gene programs. This 'switch' to pro-inflammatory sensing of apoptotic cells resulted from the disruption of the chloride-sensing pathway (and not due to corpse overload or poor degradation), including the chloride-sensing kinases WNK1, OSR1 and SPAK-which function upstream of SLC12A2-had a similar effect on efferocytosis. Collectively, the WNK1-OSR1-SPAK-SLC12A2/SLC12A4 chloride-sensing pathway and chloride flux in phagocytes are key modifiers of the manner in which phagocytes interpret the engulfed apoptotic corpse.
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23
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Cao X, Baharozian C, Hughes BA. Electrophysiological impact of thiocyanate on isolated mouse retinal pigment epithelial cells. Am J Physiol Cell Physiol 2019; 316:C792-C804. [PMID: 30892935 DOI: 10.1152/ajpcell.00010.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our recent electrophysiological analysis of mouse retinal pigment epithelial (RPE) cells revealed that in the presence of 10 mM external thiocyanate (SCN-), voltage steps generated large transient currents whose time-dependent decay most likely results from the accumulation or depletion of SCN- intracellularly. In the present study, we investigated the effects of more physiologically relevant concentrations of this biologically active anion. In whole cell recordings of C57BL/6J mouse RPE cells, we found that, over the range of 50 to 500 µM SCN-, the amplitude of transient currents evoked by voltage steps was proportional to the extracellular SCN- concentration. Transient currents were also produced in RPE cells when the membrane potential was held constant and the external SCN- concentration was rapidly increased by pressure-ejecting 500 µM SCN- from a second pipette. Other results indicate that the time dependence of currents produced by both approaches results from a change in driving force due to intracellular SCN- accumulation or depletion. Finally, by applying fluorescence imaging and voltage-clamping techniques to BALB/c mouse RPE cells loaded with the anion-sensitive dye MQAE, we demonstrated that in the presence of 200 or 500 µM extracellular SCN-, depolarizing voltage steps increased the cytoplasmic SCN- concentration to an elevated steady state within several seconds. Collectively, these results indicate that, in the presence of physiological concentrations of SCN- outside the RPE, the conductance and permeability of the RPE cell membranes for SCN- are sufficiently large that SCN- rapidly approaches electrochemical equilibrium within the cytoplasm when the membrane voltage or external SCN- concentration is perturbed.
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Affiliation(s)
- Xu Cao
- Department of Ophthalmology and Visual Sciences, University of Michigan , Ann Arbor, Michigan
| | - Connor Baharozian
- Department of Ophthalmology and Visual Sciences, University of Michigan , Ann Arbor, Michigan
| | - Bret A Hughes
- Department of Ophthalmology and Visual Sciences, University of Michigan , Ann Arbor, Michigan.,Department of Molecular and Integrative Physiology, University of Michigan , Ann Arbor, Michigan
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24
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Abstract
Recently, we showed that synthetic anion transporters DSC4P-1 and SA-3 had activity related to cancer cell death. They were found to increase intracellular chloride and sodium ion concentrations. They were also found to induce apoptosis (DSC4P-1) and both induce apoptosis and inhibit autophagy (SA-3). However, determinants underlying these phenomenological findings were not elucidated. The absence of mechanistic understanding has limited the development of yet-improved systems. Here, we show that three synthetic anion transporters, DSC4P-1, SA-3, and 8FC4P, induce osmotic stress in cells by increasing intracellular ion concentrations. This triggers the generation of reactive oxygen species via a sequential process and promotes caspase-dependent apoptosis. In addition, two of the transporters, SA-3 and 8FC4P, induce autophagy by increasing the cytosolic calcium ion concentration promoted by osmotic stress. However, they eventually inhibit the autophagy process as a result of their ability to disrupt lysosome function through a transporter-mediated decrease in a lysosomal chloride ion concentration and an increase in the lysosomal pH.
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25
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Yang J, Sun L, Hao L, Yang GG, Zou ZC, Cao Q, Ji LN, Mao ZW. A halogen ion-selective phosphorescence turn-on probe based on induction of Pt–Pt interactions. Chem Commun (Camb) 2019; 55:11191-11194. [DOI: 10.1039/c9cc05093k] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A halogen ion induced self-assembly of square-planar platinum complexes has been, for the first time, observed and applied as a turn-on phosphorescent probe for Cl−.
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Affiliation(s)
- Jing Yang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry
- School of Chemistry
- Sun Yat-Sen University
- Guangzhou 510275
- P. R. China
| | - Lili Sun
- School of Materials Science and Engineering
- Sun Yat-Sen University
- Guangzhou 510275
- P. R. China
| | - Liang Hao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry
- School of Chemistry
- Sun Yat-Sen University
- Guangzhou 510275
- P. R. China
| | - Gang-Gang Yang
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry
- School of Chemistry
- Sun Yat-Sen University
- Guangzhou 510275
- P. R. China
| | - Zhi-Cong Zou
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry
- School of Chemistry
- Sun Yat-Sen University
- Guangzhou 510275
- P. R. China
| | - Qian Cao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry
- School of Chemistry
- Sun Yat-Sen University
- Guangzhou 510275
- P. R. China
| | - Liang-Nian Ji
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry
- School of Chemistry
- Sun Yat-Sen University
- Guangzhou 510275
- P. R. China
| | - Zong-Wan Mao
- MOE Key Laboratory of Bioinorganic and Synthetic Chemistry
- School of Chemistry
- Sun Yat-Sen University
- Guangzhou 510275
- P. R. China
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26
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Zhang F, Ma C, Wang Y, Liu W, Liu X, Zhang H. Fluorescent probes for chloride ions in biological samples. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2018; 205:428-434. [PMID: 30053636 DOI: 10.1016/j.saa.2018.07.060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 07/16/2018] [Accepted: 07/20/2018] [Indexed: 06/08/2023]
Abstract
As one of the most widespread anions, chloride ion largely existed in the water sources as well as living organism. Therefore, determination of chloride ions in biological samples is evidently important. Herein, we developed two analogous fluorescence probes BeQ1 and BeQ2 for the sensitive detection of chloride ions. The chloride ions in biological samples were determined by a direct and simple method with the detection limit of 46 and 66 μM respectively. In addition, the probes were found having the two-photon excitation property.
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Affiliation(s)
- Fengyuan Zhang
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China; School of Basic Medical Science, Ningxia Medical University, Yinchuan 750004, China
| | - Chen Ma
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Yaya Wang
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Wei Liu
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Xiaoyan Liu
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China
| | - Haixia Zhang
- College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, China.
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27
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Park SH, Hyun JY, Shin I. A lysosomal chloride ion-selective fluorescent probe for biological applications. Chem Sci 2018; 10:56-66. [PMID: 30746073 PMCID: PMC6334773 DOI: 10.1039/c8sc04084b] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 11/08/2018] [Indexed: 01/07/2023] Open
Abstract
Lysosomal pHs are maintained at low values by the cooperative action of a proton pump and a chloride channel to maintain electroneutrality. Owing to the biological significance of lysosomal chloride ions, measurements of their levels are of great importance to understand lysosome-associated biological events. However, appropriate probes to selectively detect Cl- ions within acidic lysosomes have not been developed to date. In this study, we prepared MQAE-MP, a lysosomal Cl--selective fluorescent probe, and applied it to gain information about biological processes associated with lysosomes. The fluorescence of MQAE-MP is pH-insensitive over physiological pH ranges and is quenched by Cl- with a Stern-Volmer constant of 204 M-1. Because MQAE-MP detects lysosomal Cl- selectively, it was employed to assess the effects of eleven substances on lysosomal Cl- concentrations. The results show that lysosomal Cl- concentrations decrease in cells treated with substances that inhibit proteins responsible for lysosomal membrane stabilization, induce lysosomal membrane permeabilization, and transport lysosomal Cl- to the cytosol. In addition, we investigated the effect of lysosomal chloride ions on the fusion of autophagosomes with lysosomes to generate autolysosomes during autophagy inhibition promoted by substances. It was found that changes in lysosomal Cl- concentrations did not affect the fusion of autophagosomes with lysosomes but an increase in the cytosolic Ca2+ concentration blocked the fusion process. We demonstrate from the current study that MQAE-MP has great potential as a lysosomal Cl--selective fluorescent probe for studies of biological events associated with lysosomes.
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Affiliation(s)
- Sang-Hyun Park
- Center for Biofunctional Molecules , Department of Chemistry , Yonsei University , Seoul 03722 , Republic of Korea .
| | - Ji Young Hyun
- Center for Biofunctional Molecules , Department of Chemistry , Yonsei University , Seoul 03722 , Republic of Korea .
| | - Injae Shin
- Center for Biofunctional Molecules , Department of Chemistry , Yonsei University , Seoul 03722 , Republic of Korea .
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28
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Robinson E, MacDonald KD, Slaughter K, McKinney M, Patel S, Sun C, Sahay G. Lipid Nanoparticle-Delivered Chemically Modified mRNA Restores Chloride Secretion in Cystic Fibrosis. Mol Ther 2018; 26:2034-2046. [PMID: 29910178 PMCID: PMC6094356 DOI: 10.1016/j.ymthe.2018.05.014] [Citation(s) in RCA: 166] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 05/12/2018] [Accepted: 05/12/2018] [Indexed: 12/14/2022] Open
Abstract
The promise of gene therapy for the treatment of cystic fibrosis has yet to be fully clinically realized despite years of effort toward correcting the underlying genetic defect in the cystic fibrosis transmembrane conductance regulator (CFTR). mRNA therapy via nanoparticle delivery represents a powerful technology for the transfer of genetic material to cells with large, widespread populations, such as airway epithelia. We deployed a clinically relevant lipid-based nanoparticle (LNP) for packaging and delivery of large chemically modified CFTR mRNA (cmCFTR) to patient-derived bronchial epithelial cells, resulting in an increase in membrane-localized CFTR and rescue of its primary function as a chloride channel. Furthermore, nasal application of LNP-cmCFTR restored CFTR-mediated chloride secretion to conductive airway epithelia in CFTR knockout mice for at least 14 days. On day 3 post-transfection, CFTR activity peaked, recovering up to 55% of the net chloride efflux characteristic of healthy mice. This magnitude of response is superior to liposomal CFTR DNA delivery and is comparable with outcomes observed in the currently approved drug ivacaftor. LNP-cmRNA-based systems represent a powerful platform technology for correction of cystic fibrosis and other monogenic disorders.
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Affiliation(s)
- Ema Robinson
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR 97201, USA
| | - Kelvin D MacDonald
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR 97201, USA; Department of Pediatrics, School of Medicine, Oregon Health and Science University, Portland, OR 97239, USA
| | - Kai Slaughter
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR 97201, USA
| | - Madison McKinney
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR 97201, USA
| | - Siddharth Patel
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR 97201, USA
| | - Conroy Sun
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR 97201, USA; Department of Radiation Medicine, School of Medicine, Oregon Health and Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Gaurav Sahay
- Department of Pharmaceutical Sciences, College of Pharmacy, Oregon State University, Portland, OR 97201, USA; Department of Biomedical Engineering, Oregon Health and Science University, Portland, OR 97201, USA.
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29
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Vallejos S, Hernando E, Trigo M, García FC, García-Valverde M, Iturbe D, Cabero MJ, Quesada R, García JM. Polymeric chemosensor for the detection and quantification of chloride in human sweat. Application to the diagnosis of cystic fibrosis. J Mater Chem B 2018; 6:3735-3741. [PMID: 32254835 DOI: 10.1039/c8tb00682b] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We have developed a new extremely hydrophilic polymeric film suitable for the detection and quantification of chloride in human sweat directly on the skin. The film, or membrane, has chemically anchored 6-methoxyquinoline groups as chloride responsive fluorescent motifs. We have prepared the sensory material from a standard vinyl copolymer, by a convenient and easy solid-phase reaction. The sensory material has a water swelling percentage of 700%, facilitating an immediate detection of chloride, is reusable for at least 6 cycles and can be handled without care by unskilled persons. The initially high fluorescence of the material decreases in the presence of chloride, allowing the quantification of chloride concentration by using the colour definition of a digital picture or a fluorimeter. The suitability of the material to perform quantitative chloride analysis of human sweat by putting it in contact with the skin offers promise for its application in the sweat test used for the diagnosis of cystic fibrosis (CF).
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Affiliation(s)
- Saúl Vallejos
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Plaza de Misael Bañuelos s/n, 09001 Burgos, Spain.
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30
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Ikeuchi Y, Kogiso H, Hosogi S, Tanaka S, Shimamoto C, Inui T, Nakahari T, Marunaka Y. Measurement of [Cl -] i unaffected by the cell volume change using MQAE-based two-photon microscopy in airway ciliary cells of mice. J Physiol Sci 2018; 68:191-199. [PMID: 29332212 PMCID: PMC10717022 DOI: 10.1007/s12576-018-0591-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 01/04/2018] [Indexed: 11/28/2022]
Abstract
MQAE is a 'non-ratiometric' chloride ion (Cl-)-quenched fluorescent indicator that is used to determine intracellular Cl- concentration ([Cl-]i). MQAE-based two-photon microscopy is reported to be a useful method to measure [Cl-]i, but it is still controversial because a change in cell volume may alter the MQAE concentration, leading to a change in the fluorescence intensity without any change in [Cl-]i. In an attempt to elucidate the effect or lack of effect of cell volume on MQAE concentration, we studied the effects of changes in cell volume, achieved by applying different levels of osmotic stress, on the intensity of MQAE fluorescence in airway ciliary cells. To study solely the effect of changes in cell volume on MQAE fluorescence intensity, i.e., excluding the effect of any change in [Cl-]i, we first conducted the experiments in a Cl--free nitrate (NO3-) solution to substitute NO3- (non-quenching anion for MQAE fluorescence) for Cl- in the intracellular fluid. Hypo- (- 30 mM NaNO3) or hyper-osmotic stress (+ 30 mM NaNO3) effected changes in cell volume, but the stress did not result in any significant change in MQAE fluorescence intensity. The experiments were also carried out in Cl--containing solution. Hypo-osmotic stress (- 30 mM NaCl) increased both MQAE fluorescence intensity and cell volume, while hyper-osmotic stress (+ 30 mM NaCl) decreased both of these properties. These results suggest that the osmotic stress-induced change in MQAE fluorescence intensity was caused by the change in [Cl-]i and not by the MQAE concentration. Moreover, the intracellular distribution of MQAEs was heterogeneous and not affected by the changes in osmotic stress-induced cell volume, suggesting that MQAEs are bound to un-identified subcellular structures. These bound MQAEs appear to have enabled the measurement of [Cl-]i in airway ciliary cells, even under conditions of cell volume change.
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Affiliation(s)
- Yukiko Ikeuchi
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Haruka Kogiso
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shigekuni Hosogi
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Saori Tanaka
- Laboratory of Pharmacotherapy, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Chikao Shimamoto
- Laboratory of Pharmacotherapy, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | | | - Takashi Nakahari
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
- Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
- Japan Institute for Food Education and Health, St Agnes' University, Kyoto, Japan.
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Japan Institute for Food Education and Health, St Agnes' University, Kyoto, Japan
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31
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Badugu R, Jeng BH, Reece EA, Lakowicz JR. Contact lens to measure individual ion concentrations in tears and applications to dry eye disease. Anal Biochem 2017; 542:84-94. [PMID: 29183834 DOI: 10.1016/j.ab.2017.11.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/24/2017] [Accepted: 11/18/2017] [Indexed: 11/18/2022]
Abstract
Dry eye disease (DED) affects millions of individuals in the United States and worldwide, and the incidence is increasing with an aging population. There is widespread agreement that the measurement of total tear osmolarity is the most reliable test, but this procedure provides only the total ionic strength and does not provide the concentration of each ionic species in tears. Here, we describe an approach to determine the individual ion concentrations in tears using modern silicone hydrogel (SiHG) contact lenses. We made pH (or H3O+, hydronium cation,/OH-, hydroxyl ion) and chloride ion (two of the important electrolytes in tear fluid) sensitive SiHG contact lenses. We attached hydrophobic C18 chains to water-soluble fluorescent probes for pH and chloride. The resulting hydrophobic ion sensitive fluorophores (H-ISF) bind strongly to SiHG lenses and could not be washed out with aqueous solutions. Both H-ISFs provide measurements which are independent of total intensity by use of wavelength-ratiometric measurements for pH or lifetime-based sensing for chloride. Our approach can be extended to fabricate a contact lens which provides measurements of the six dominant ionic species in tears. This capability will be valuable for research into the biochemical processes causing DED, which may improve the ability to diagnose the various types of DED.
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Affiliation(s)
- Ramachandram Badugu
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 725 W. Lombard Street, Baltimore, MD 21201, USA.
| | - Bennie H Jeng
- Department of Ophthalmology and Visual Sciences, University of Maryland School of Medicine, 419 W. Redwood Street, Suite 420, Baltimore, MD 21201, USA
| | - E Albert Reece
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD 21201, USA; Department of Biochemistry & Molecular Biology, University of Maryland School of Medicine, 655 W. Baltimore Street, Baltimore, MD 21201, USA
| | - Joseph R Lakowicz
- Center for Fluorescence Spectroscopy, Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, 725 W. Lombard Street, Baltimore, MD 21201, USA
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Glykys J, Dzhala V, Egawa K, Kahle KT, Delpire E, Staley K. Chloride Dysregulation, Seizures, and Cerebral Edema: A Relationship with Therapeutic Potential. Trends Neurosci 2017; 40:276-294. [PMID: 28431741 DOI: 10.1016/j.tins.2017.03.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 03/22/2017] [Accepted: 03/23/2017] [Indexed: 11/18/2022]
Abstract
Pharmacoresistant seizures and cytotoxic cerebral edema are serious complications of ischemic and traumatic brain injury. Intraneuronal Cl- concentration ([Cl-]i) regulation impacts on both cell volume homeostasis and Cl--permeable GABAA receptor-dependent membrane excitability. Understanding the pleiotropic molecular determinants of neuronal [Cl-]i - cytoplasmic impermeant anions, polyanionic extracellular matrix (ECM) glycoproteins, and plasmalemmal Cl- transporters - could help the identification of novel anticonvulsive and neuroprotective targets. The cation/Cl- cotransporters and ECM metalloproteinases may be particularly druggable targets for intervention. We establish here a paradigm that accounts for recent data regarding the complex regulatory mechanisms of neuronal [Cl-]i and how these mechanisms impact on neuronal volume and excitability. We propose approaches to modulate [Cl-]i that are relevant for two common clinical sequela of brain injury: edema and seizures.
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Affiliation(s)
- Joseph Glykys
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA.
| | - Volodymyr Dzhala
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Kiyoshi Egawa
- Department of Pediatrics, Hokkaido University Hospital, Sapporo 0010019, Japan
| | - Kristopher T Kahle
- Departments of Neurosurgery, Pediatrics, and Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kevin Staley
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA.
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Kataev EA, Backmann N, Shumilova TA, Rüffer T, Lang H. Calix[4]pyrroles bearing quinolinium moiety for halide sensing in aqueous solution. Supramol Chem 2016. [DOI: 10.1080/10610278.2015.1073730] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Evgeny A. Kataev
- Institute of Chemistry, Faculty of Natural Sciences, Technische Universität Chemnitz, 09107 Chemnitz, Germany
| | - Nanett Backmann
- Institute of Chemistry, Faculty of Natural Sciences, Technische Universität Chemnitz, 09107 Chemnitz, Germany
| | - Tatiana A. Shumilova
- Institute of Chemistry, Faculty of Natural Sciences, Technische Universität Chemnitz, 09107 Chemnitz, Germany
| | - Tobias Rüffer
- Institute of Chemistry, Faculty of Natural Sciences, Technische Universität Chemnitz, 09107 Chemnitz, Germany
| | - Heinrich Lang
- Institute of Chemistry, Faculty of Natural Sciences, Technische Universität Chemnitz, 09107 Chemnitz, Germany
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Nakabayashi T, Ohta N. Sensing of intracellular environments by fluorescence lifetime imaging of exogenous fluorophores. ANAL SCI 2016; 31:275-85. [PMID: 25864670 DOI: 10.2116/analsci.31.275] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Fluorescence lifetime imaging (FLIM) has been recognized as a powerful microscopy technique to examine environments in living systems. The fluorescence lifetime does not depend on the photobleaching and optical conditions, which allows us to obtain quantitative information on intracellular environments by analyzing the fluorescence lifetime. A variety of exogenous fluorophores have been applied in FLIM measurements to examine cellular processes. Information on the correlation between the fluorescence lifetime and the physiological parameters is essential to elucidate the cellular environments from the fluorescence lifetime measurements of exogenous fluorophores. In this review, exogenous fluorophores used for lifetime-based sensing are summarized, with the expectation that it becomes a basis for selecting the fluorophore used to investigate the intracellular environment with FLIM. Experimental results of the intracellular sensing of pH, metal ions, oxygen, viscosity, and other physiological parameters on the basis of the FLIM measurements are described along with a brief explanation of the mechanism of the change in the fluorescence lifetime.
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dela Peña IJI, Hong E, Kim HJ, de la Peña JB, Woo TS, Lee YS, Cheong JH. Artemisia capillaris Thunberg Produces Sedative-Hypnotic Effects in Mice, Which are Probably Mediated Through Potentiation of the GABAA Receptor. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2015; 43:667-79. [DOI: 10.1142/s0192415x1550041x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The Artemisia group of plants has long been used as a traditional remedy for various conditions. The present study assessed the sleep-promoting (sedative-hypnotic) effects of Artemisia capillaris Thunberg (A. capillaris), and elucidated a possible mechanism behind its effect. ICR mice were given A. capillaris extract (oral) at different dosages (50, 100, 200, 300, or 400 mg/kg), distilled water (oral; control), or diazepam (intraperitoneal; reference drug). One hour after administration, locomotion (open-field test) and motor coordination (rota-rod test) were assessed. The extract's effect on pentobarbital-induced sleep was also evaluated. Additionally, electroencephalographic (EEG) recordings were measured in rats. To evaluate a possible mechanism behind its effects, changes in chloride ( Cl -) ion influx were measured in human neuroblastoma cells. As compared to the control group, mice treated with A. capillaris demonstrated significantly decreased locomotor activity and impaired motor balance and coordination. The extract also shortened the onset and lengthened the duration of sleep induced by pentobarbital sodium. These effects were comparable to that induced by diazepam. Furthermore, A. capillaris-treated rats showed increased delta and decreased alpha EEG waves; an electroencephalographic pattern indicative of relaxation or sedation. In neuroblastoma cells, the extract dose-dependently increased Cl - ion influx, which was blocked by co-administration of bicuculline, a GABAA receptor competitive antagonist, suggesting that its effects are mediated through the GABAA receptor– Cl - ion channel complex. Altogether, the results of the present study demonstrate that A. capillaris possesses potent sedative-hypnotic effects, which are probably mediated through potentiation of the GABAA receptor– Cl - ion channel complex.
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Affiliation(s)
- Irene Joy I. dela Peña
- Uimyung Research Institute for Neuroscience, Department of Pharmacy, Sahmyook University, Seoul 139-742, Republic of Korea
| | - Eunyoung Hong
- Food R&D Center, CJ CheilJedang, Kyeongin-ro, Guro-gu, Seoul 152-051, Republic of Korea
| | - Hee Jin Kim
- Uimyung Research Institute for Neuroscience, Department of Pharmacy, Sahmyook University, Seoul 139-742, Republic of Korea
| | - June Bryan de la Peña
- Uimyung Research Institute for Neuroscience, Department of Pharmacy, Sahmyook University, Seoul 139-742, Republic of Korea
| | - Tae Sun Woo
- Uimyung Research Institute for Neuroscience, Department of Pharmacy, Sahmyook University, Seoul 139-742, Republic of Korea
| | - Yong Soo Lee
- Department of Pharmacology, College of Pharmacy, Duksung Women's University, Seoul 132-714, Republic of Korea
| | - Jae Hoon Cheong
- Uimyung Research Institute for Neuroscience, Department of Pharmacy, Sahmyook University, Seoul 139-742, Republic of Korea
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36
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Ionic imbalance, in addition to molecular crowding, abates cytoskeletal dynamics and vesicle motility during hypertonic stress. Proc Natl Acad Sci U S A 2015; 112:E3104-13. [PMID: 26045497 DOI: 10.1073/pnas.1421290112] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Cell volume homeostasis is vital for the maintenance of optimal protein density and cellular function. Numerous mammalian cell types are routinely exposed to acute hypertonic challenge and shrink. Molecular crowding modifies biochemical reaction rates and decreases macromolecule diffusion. Cell volume is restored rapidly by ion influx but at the expense of elevated intracellular sodium and chloride levels that persist long after challenge. Although recent studies have highlighted the role of molecular crowding on the effects of hypertonicity, the effects of ionic imbalance on cellular trafficking dynamics in living cells are largely unexplored. By tracking distinct fluorescently labeled endosome/vesicle populations by live-cell imaging, we show that vesicle motility is reduced dramatically in a variety of cell types at the onset of hypertonic challenge. Live-cell imaging of actin and tubulin revealed similar arrested microfilament motility upon challenge. Vesicle motility recovered long after cell volume, a process that required functional regulatory volume increase and was accelerated by a return of extracellular osmolality to isosmotic levels. This delay suggests that, although volume-induced molecular crowding contributes to trafficking defects, it alone cannot explain the observed effects. Using fluorescent indicators and FRET-based probes, we found that intracellular ATP abundance and mitochondrial potential were reduced by hypertonicity and recovered after longer periods of time. Similar to the effects of osmotic challenge, isovolumetric elevation of intracellular chloride concentration by ionophores transiently decreased ATP production by mitochondria and abated microfilament and vesicle motility. These data illustrate how perturbed ionic balance, in addition to molecular crowding, affects membrane trafficking.
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37
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Rungta R, Choi H, Tyson J, Malik A, Dissing-Olesen L, Lin P, Cain S, Cullis P, Snutch T, MacVicar B. The Cellular Mechanisms of Neuronal Swelling Underlying Cytotoxic Edema. Cell 2015; 161:610-621. [DOI: 10.1016/j.cell.2015.03.029] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/03/2015] [Accepted: 03/12/2015] [Indexed: 01/08/2023]
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38
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Deidda G, Parrini M, Naskar S, Bozarth IF, Contestabile A, Cancedda L. Reversing excitatory GABAAR signaling restores synaptic plasticity and memory in a mouse model of Down syndrome. Nat Med 2015; 21:318-26. [PMID: 25774849 DOI: 10.1038/nm.3827] [Citation(s) in RCA: 185] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 02/19/2015] [Indexed: 12/12/2022]
Abstract
Down syndrome (DS) is the most frequent genetic cause of intellectual disability, and altered GABAergic transmission through Cl(-)-permeable GABAA receptors (GABAARs) contributes considerably to learning and memory deficits in DS mouse models. However, the efficacy of GABAergic transmission has never been directly assessed in DS. Here GABAAR signaling was found to be excitatory rather than inhibitory, and the reversal potential for GABAAR-driven Cl(-) currents (ECl) was shifted toward more positive potentials in the hippocampi of adult DS mice. Accordingly, hippocampal expression of the cation Cl(-) cotransporter NKCC1 was increased in both trisomic mice and individuals with DS. Notably, NKCC1 inhibition by the FDA-approved drug bumetanide restored ECl, synaptic plasticity and hippocampus-dependent memory in adult DS mice. Our findings demonstrate that GABA is excitatory in adult DS mice and identify a new therapeutic approach for the potential rescue of cognitive disabilities in individuals with DS.
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Affiliation(s)
- Gabriele Deidda
- Neuroscience and Brain Technologies Department, Istituto Italiano di Tecnologia, Genova, Italy
| | - Martina Parrini
- Neuroscience and Brain Technologies Department, Istituto Italiano di Tecnologia, Genova, Italy
| | - Shovan Naskar
- Neuroscience and Brain Technologies Department, Istituto Italiano di Tecnologia, Genova, Italy
| | - Ignacio F Bozarth
- Neuroscience and Brain Technologies Department, Istituto Italiano di Tecnologia, Genova, Italy
| | - Andrea Contestabile
- Neuroscience and Brain Technologies Department, Istituto Italiano di Tecnologia, Genova, Italy
| | - Laura Cancedda
- Neuroscience and Brain Technologies Department, Istituto Italiano di Tecnologia, Genova, Italy
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39
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Kantner K, Ashraf S, Carregal-Romero S, Carrillo-Carrion C, Collot M, Del Pino P, Heimbrodt W, De Aberasturi DJ, Kaiser U, Kazakova LI, Lelle M, de Baroja NM, Montenegro JM, Nazarenus M, Pelaz B, Peneva K, Gil PR, Sabir N, Schneider LM, Shabarchina LI, Sukhorukov GB, Vazquez M, Yang F, Parak WJ. Particle-based optical sensing of intracellular ions at the example of calcium - what are the experimental pitfalls? SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:896-904. [PMID: 25504784 DOI: 10.1002/smll.201402110] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 09/24/2014] [Indexed: 06/04/2023]
Abstract
Colloidal particles with fluorescence read-out are commonly used as sensors for the quantitative determination of ions. Calcium, for example, is a biologically highly relevant ion in signaling, and thus knowledge of its spatio-temporal distribution inside cells would offer important experimental data. However, the use of particle-based intracellular sensors for ion detection is not straightforward. Important associated problems involve delivery and intracellular location of particle-based fluorophores, crosstalk of the fluorescence read-out with pH, and spectral overlap of the emission spectra of different fluorophores. These potential problems are outlined and discussed here with selected experimental examples. Potential solutions are discussed and form a guideline for particle-based intracellular imaging of ions.
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Affiliation(s)
- Karsten Kantner
- Fachbereich Physik, Philipps- Universität Marburg, Marburg, Germany
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40
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Cho CH. Star players sidelined in chloride homeostasis in neurons. Front Cell Neurosci 2014; 8:114. [PMID: 24795569 PMCID: PMC4006059 DOI: 10.3389/fncel.2014.00114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 04/07/2014] [Indexed: 11/24/2022] Open
Affiliation(s)
- Chang-Hoon Cho
- Graduate School of Life Science, Institute of Biotechnology, Korea University Seoul, Korea
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41
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de la Peña JBI, Kim CA, Lee HL, Yoon SY, Kim HJ, Hong EY, Kim GH, Ryu JH, Lee YS, Kim KM, Cheong JH. Luteolin mediates the antidepressant-like effects of Cirsium japonicum in mice, possibly through modulation of the GABAA receptor. Arch Pharm Res 2013; 37:263-9. [PMID: 23925560 DOI: 10.1007/s12272-013-0229-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/26/2013] [Indexed: 10/26/2022]
Abstract
Cirsium japonicum (CJ) has been shown to possess antidepressant-like properties. In the present study, we sought to identify which constituent of CJ might be responsible for its antidepressant effects and determine probable mechanism of action. The ethanol extract of CJ was administered to mice then behavioral changes were evaluated in the forced-swimming test (FST) and open-field test (OFT). In addition, its effects on norepinephrine (NE) reuptake and intracellular chloride (Cl(-)) flux were determined, in vitro. The effects of CJ's major constituents (linarin, pectolinarin, chlorogenic acid, luteolin) were also evaluated. CJ showed antidepressant-like effect by significantly reducing immobile behavior of mice in the FST, without increasing locomotor activity in the OFT. CJ had no effect on monoamine (NE) uptake, but it significantly promoted Cl(-) ion influx in human neuroblastoma cells. This CJ-induced Cl(-) influx was significantly blocked by co-administration of the competitive GABAA receptor antagonist, bicuculline. Among the major constituents of the CJ extract, only luteolin produced similar antidepressant-like effect, in vivo, and Cl(-) ion influx, in vitro. Altogether, the present results suggest that the antidepressant-like effect of CJ was most probably induced by its constituent luteolin, mediated through potentiation of the GABAA receptor-Cl(-) ion channel complex.
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Affiliation(s)
- June Bryan I de la Peña
- Department of Pharmacy, Uimyung Research Institute for Neuroscience, Sahmyook University, 26-21 Kongneung-2-dong, Nowon-gu, Seoul, 139-742, Republic of Korea
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42
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Liu X, Hong SI, Park SJ, dela Peña JB, Che H, Yoon SY, Kim DH, Kim JM, Cai M, Risbrough V, Geyer MA, Shin CY, Cheong JH, Park H, Lew JH, Ryu JH. The ameliorating effects of 5,7-dihydroxy-6-methoxy-2(4-phenoxyphenyl)-4H-chromene-4-one, an oroxylin A derivative, against memory impairment and sensorimotor gating deficit in mice. Arch Pharm Res 2013; 36:854-63. [DOI: 10.1007/s12272-013-0106-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Accepted: 03/21/2013] [Indexed: 12/31/2022]
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43
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The involvement of magnoflorine in the sedative and anxiolytic effects of Sinomeni Caulis et Rhizoma in mice. J Nat Med 2013; 67:814-21. [DOI: 10.1007/s11418-013-0754-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 02/14/2013] [Indexed: 10/27/2022]
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44
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Oglesby IK, Chotirmall SH, McElvaney NG, Greene CM. Regulation of cystic fibrosis transmembrane conductance regulator by microRNA-145, -223, and -494 is altered in ΔF508 cystic fibrosis airway epithelium. THE JOURNAL OF IMMUNOLOGY 2013; 190:3354-62. [PMID: 23436935 DOI: 10.4049/jimmunol.1202960] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Expression of the cystic fibrosis transmembrane conductance regulator (CFTR) is altered in individuals with the ΔF508 CFTR mutation. We previously reported differential expression of microRNA (miRNA) in CF airway epithelium; however, the role of miRNA in regulation of CFTR expression here remains unexplored. In this study, we investigated the role of upregulated miRNAs in CFTR regulation in vivo in bronchial brushings from individuals homozygous or heterozygous for ΔF508 CFTR, validated our observations in vitro, and assessed the impact of defective chloride ion conductance, genotype, and colonization status on miRNA expression. miRNA target prediction was performed in silico, and expression of miRNA and target genes were measured by quantitative real-time PCR and/or Western blotting. Overexpression and inhibition studies were performed with pre-miRs or antimiRs, respectively, and a luciferase reporter gene was used to elucidate direct miRNA-target interactions. miR-145, miR-223, and miR-494 were upregulated in CF versus non-CF bronchial brushings and cell lines; in ΔF508 CFTR homozygotes versus heterozygotes; in subjects positive for P. aeruginosa; and in cells treated with a CFTR inhibitor or IL-1β. Reciprocal downregulation or upregulation of CFTR gene and/or protein expression was observed after miRNA manipulation and direct miRNA-target relationships demonstrated via a reporter system containing a wild type or mutated full-length CFTR 3' untranslated region. Increased expression of miR-145, miR-223, and miR-494 in vivo in bronchial epithelium of individuals carrying the ΔF508 CFTR mutation correlates with decreased CFTR expression. Defective CFTR function, Pseudomonas colonization, and inflammation may affect miRNA expression and contribute to the regulation of ΔF508 CFTR.
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Affiliation(s)
- Irene K Oglesby
- Respiratory Research Division, Department of Medicine, Education and Research Centre, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland
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45
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Mao X, Li H. Chiral imaging in living cells with functionalized graphene oxide. J Mater Chem B 2013; 1:4267-4272. [DOI: 10.1039/c3tb20729c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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46
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Trigeminal ganglion neurons of mice show intracellular chloride accumulation and chloride-dependent amplification of capsaicin-induced responses. PLoS One 2012; 7:e48005. [PMID: 23144843 PMCID: PMC3493563 DOI: 10.1371/journal.pone.0048005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 09/19/2012] [Indexed: 12/21/2022] Open
Abstract
Intracellular Cl− concentrations ([Cl−]i) of sensory neurons regulate signal transmission and signal amplification. In dorsal root ganglion (DRG) and olfactory sensory neurons (OSNs), Cl− is accumulated by the Na+-K+-2Cl− cotransporter 1 (NKCC1), resulting in a [Cl−]i above electrochemical equilibrium and a depolarizing Cl− efflux upon Cl− channel opening. Here, we investigate the [Cl−]i and function of Cl− in primary sensory neurons of trigeminal ganglia (TG) of wild type (WT) and NKCC1−/− mice using pharmacological and imaging approaches, patch-clamping, as well as behavioral testing. The [Cl−]i of WT TG neurons indicated active NKCC1-dependent Cl− accumulation. Gamma-aminobutyric acid (GABA)A receptor activation induced a reduction of [Cl−]i as well as Ca2+ transients in a corresponding fraction of TG neurons. Ca2+ transients were sensitive to inhibition of NKCC1 and voltage-gated Ca2+ channels (VGCCs). Ca2+ responses induced by capsaicin, a prototypical stimulus of transient receptor potential vanilloid subfamily member-1 (TRPV1) were diminished in NKCC1−/− TG neurons, but elevated under conditions of a lowered [Cl−]o suggesting a Cl−-dependent amplification of capsaicin-induced responses. Using next generation sequencing (NGS), we found expression of different Ca2+-activated Cl− channels (CaCCs) in TGs of mice. Pharmacological inhibition of CaCCs reduced the amplitude of capsaicin-induced responses of TG neurons in Ca2+ imaging and electrophysiological recordings. In a behavioral paradigm, NKCC1−/− mice showed less avoidance of the aversive stimulus capsaicin. In summary, our results strongly argue for a Ca2+-activated Cl−-dependent signal amplification mechanism in TG neurons that requires intracellular Cl− accumulation by NKCC1 and the activation of CaCCs.
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Domínguez R, Rodríguez A, Maestre A, Robina I, Moyá ML. Synthesis and physicochemical characterization of alkanedyil-α-ω-bis(dimethyldodecylammonium) bromide, 12-s-12,2Br−, surfactants with s=7, 9, 11 in aqueous medium. J Colloid Interface Sci 2012; 386:228-39. [DOI: 10.1016/j.jcis.2012.06.089] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/26/2012] [Accepted: 06/27/2012] [Indexed: 10/28/2022]
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Roomans GM. Pharmacological Approaches to Correcting the Ion Transport Defect in Cystic Fibrosis. ACTA ACUST UNITED AC 2012; 2:413-31. [PMID: 14719993 DOI: 10.1007/bf03256668] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cystic fibrosis (CF) is a lethal genetic disease caused by a mutation in a membrane protein, the cystic fibrosis transmembrane conductance regulator (CFTR), which mainly (but not exclusively) functions as a chloride channel. The main clinical symptoms are chronic obstructive lung disease, which is responsible for most of the morbidity and mortality associated with CF, and pancreatic insufficiency. About 1000 mutations of the gene coding for CFTR are currently known; the most common of these, present in the great majority of the patients (Delta508) results in the deletion of a phenylalanine at position 508. In this mutation, the aberrant CFTR is not transported to the membrane but degraded in the ubiquitin-proteasome pathway. The aim of this review is to give an overview of the pharmacologic strategies currently used in attempts to overcome the ion transport defect in CF. One strategy to develop pharmacologic treatment for CF is to inhibit the breakdown of DeltaF508-CFTR by interfering with the chaperones involved in the folding of CFTR. At least in in vitro systems, this can be accomplished by sodium phenylbutyrate, or S-nitrosoglutathione (GSNO), and also by genistein or benzo[c]quinolizinium compounds. It is also possible to stimulate CFTR or its mutated forms, when present in the plasma membrane, using xanthines, genistein, and various other compounds, such as benzamidizoles and benzoxazoles, benzo[c]quinolizinium compounds or phenantrolines. Experimental results are not always unambiguous, and adverse effects have been incompletely tested. Some clinical tests have been done on sodium phenyl butyrate, GSNO and genistein, mostly in respect to other diseases, and the results demonstrate that these drugs are reasonably well tolerated. Their efficiency in the treatment of CF has not yet been demonstrated, however. An alternative strategy is to compensate for the defective chloride transport by CFTR by stimulation of other chloride channels. This can be done via purinergic receptors. A phase I study using a stable uridine triphosphate analog has recently been completed. A second alternative strategy is to attempt to maintain hydration of the airway mucus by inhibiting Na(+) uptake by the epithelial Na(+) channel using amiloride or stable analogs of amiloride. Clinical tests so far have been inconclusive. A number of other suggestions are currently being explored. The minority of patients with CF who have a stop mutation may benefit from treatment with gentamicin. The difficulties in finding a pharmacologic treatment for CF may be due to the fact that CFTR has additional functions besides chloride transport, and interfering with CFTR biosynthesis or activation implies interference with central cellular processes, which may have undesirable adverse effects.
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Affiliation(s)
- Godfried M Roomans
- Department of Medical Cell Biology, University of Uppsala, Uppsala, Sweden.
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Mao S, Garzon-Muvdi T, Di Fulvio M, Chen Y, Delpire E, Alvarez FJ, Alvarez-Leefmans FJ. Molecular and functional expression of cation-chloride cotransporters in dorsal root ganglion neurons during postnatal maturation. J Neurophysiol 2012; 108:834-52. [PMID: 22457464 PMCID: PMC3424090 DOI: 10.1152/jn.00970.2011] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 03/28/2012] [Indexed: 12/30/2022] Open
Abstract
GABA depolarizes and excites central neurons during early development, becoming inhibitory and hyperpolarizing with maturation. This "developmental shift" occurs abruptly, reflecting a decrease in intracellular Cl(-) concentration ([Cl(-)](i)) and a hyperpolarizing shift in Cl(-) equilibrium potential due to upregulation of the K(+)-Cl(-) cotransporter KCC2b, a neuron-specific Cl(-) extruder. In contrast, primary afferent neurons (PANs) are depolarized by GABA throughout adulthood because of expression of NKCC1, a Na(+)-K(+)-2Cl(-) cotransporter that accumulates Cl(-) above equilibrium. The GABA(A)-mediated depolarization of PANs determines presynaptic inhibition in the spinal cord, a key mechanism gating somatosensory information. Little is known about developmental changes in Cl(-) transporter expression and Cl(-) homeostasis in PANs. Whether NKCC1 is expressed in PANs of all phenotypes or is restricted to subpopulations (e.g., nociceptors) is debatable. Likewise, whether PANs express KCC2s is controversial. We investigated NKCC1 and K(+)-Cl(-) cotransporter expression in rat and mouse dorsal root ganglion (DRG) neurons with molecular methods. Using fluorescence imaging microscopy, we measured [Cl(-)](i) in acutely dissociated rat DRG neurons (P0-P21) loaded with N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide and classified with phenotypic markers. DRG neurons of all sizes express two NKCC1 mRNAs, one full-length and a shorter splice variant lacking exon 21. Immunolabeling with validated antibodies revealed ubiquitous expression of NKCC1 in DRG neurons irrespective of postnatal age and phenotype. As maturation progresses [Cl(-)](i) decreases gradually, persisting above equilibrium in >95% mature neurons. DRG neurons express mRNAs for KCC1, KCC3s, and KCC4, but not for KCC2s. Mechanisms underlying PANs' developmental changes in Cl(-) homeostasis are discussed and compared with those of central neurons.
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Affiliation(s)
- Shihong Mao
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435-0001, USA
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Kovalchuk Y, Garaschuk O. Two-photon chloride imaging using MQAE in vitro and in vivo. Cold Spring Harb Protoc 2012; 2012:778-85. [PMID: 22753606 DOI: 10.1101/pdb.prot070037] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
This protocol describes a technique for high-resolution chloride imaging of living cells using a quinoline-based chloride (Cl(-)) indicator dye, MQAE (N-[6-methoxyquinolyl] acetoethyl ester). Bath-applied to acute brain slices, MQAE provides high-quality labeling of neuronal cells and their processes. In living anesthetized mice, cortical cells are labeled using the multicell bolus loading procedure. In combination with two-photon microscopy, this procedure enables in vivo visualization of cell bodies of neurons and astrocytes as well as some astrocytic processes and allows one to monitor changes in the intracellular chloride concentration in dozens of individual cells.
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