Chlorotoxin inhibits glioma cell invasion via matrix metalloproteinase-2.
AuthorsDeshane J, Garner CC, Sontheimer H
JournalJ Biol Chem
PubMed ID12454020
'Primary brain tumors (gliomas) have the unusual ability to diffusely infiltrate the normal brain thereby evading surgical treatment. Chlorotoxin is a scorpion toxin that specifically binds to the surface of glioma cells and impairs their ability to invade. Using a recombinant His-Cltx we isolated and identified the principal Cltx receptor ... More
Using confocal microscopy and the fluorescent indicator, 6-methoxy-N-ethylquinolinium iodide, to measure changes in intracellular chloride.
AuthorsInglefield JR, Schwartz-Bloom RD
JournalMethods Enzymol
PubMed ID10506989
Assessment of swelling-activated Cl- channels using the halide-sensitive fluorescent indicator 6-methoxy-N-(3-sulfopropyl)quinolinium.
AuthorsSrinivas SP, Bonanno JA, Hughes BA
JournalBiophys J
PubMed ID9649372
'This study describes a quantitative analysis of the enhancement in anion permeability through swelling-activated Cl- channels, using the halide-sensitive fluorescent dye 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ). Cultured bovine corneal endothelial monolayers perfused with NO3- Ringer''s were exposed to I- pulses under isosmotic and, subsequently, hyposmotic conditions. Changes in SPQ fluorescence due to I- ... More
Halide fluxes in epithelial cells measured with an automated cell plate reader.
AuthorsMahlangu DA, Dix JA
JournalAnal Biochem
PubMed ID14715281
'A method is introduced to measure chloride permeability in cultured epithelial cells using 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ) and 6-methoxy-N-ethylquinolinium iodide quinolinium (MEQ) as fluorescent chloride-sensitive probes. The method involves growing cells in multiwell plates, incubating cells with SPQ or MEQ, and then exchanging intracellular or extracellular halide ions with nitrate. The resulting ... More
Chloride-sensitive fluorescent indicators.
AuthorsGeddes CD, Apperson K, Karolin J, Birch DJ
JournalAnal Biochem
PubMed ID11373079
'Three fluorescent halide-sensitive quinolinium dyes have been produced by the reaction of the 6-methylquinoline heterocyclic nitrogen base with methyl bromide, methyl iodide, and 3-bromo-1-propanol. The quaternary salts, unlike the precursor molecule, are readily water soluble and the fluorescence intensity of these salts is reduced in the presence of aqueous chloride, ... More
Changes in intracellular chloride after oxygen-glucose deprivation of the adult hippocampal slice: effect of diazepam.
AuthorsGaleffi F, Sah R, Pond BB, George A, Schwartz-Bloom RD
JournalJ Neurosci
PubMed ID15128862
'Ischemic injury to the CNS results in loss of ionic homeostasis and the development of neuronal death. An increase in intracellular Ca2+ is well established, but there are few studies of changes in intracellular Cl- ([Cl-]i) after ischemia. We used an in vitro model of cerebral ischemia (oxygen-glucose deprivation) to ... More
Confocal imaging of intracellular chloride in living brain slices: measurement of GABAA receptor activity.
AuthorsInglefield JR, Schwartz-Bloom RD
JournalJ Neurosci Methods
PubMed ID9288644
'We have developed a method using UV laser-scanning confocal microscopy and the fluorescent chloride ion indicator, 6-methoxy-N-ethylquinolinium chloride (MEQ), to image GABA-mediated changes in intracellular chloride (Cli-) in individual neurons of the rat acute brain slice. After bath-loading slices with the cell-permeant form (reduced) of MEQ, there was intense fluorescence ... More
Optical imaging of hippocampal neurons with a chloride-sensitive dye: early effects of in vitro ischemia.
AuthorsInglefield JR, Schwartz-Bloom RD
JournalJ Neurochem
PubMed ID9603215
'We determined if changes in intraneuronal Cl- occur early after ischemia in the hippocampal slice. Slices from juvenile rats (14-19 days old) were loaded with the cell-permeant form of 6-methoxy-N-ethylquinolinium chloride (MEQ), a Cl(-)-sensitive fluorescent dye. Real-time changes in intracellular chloride concentration ([Cl-]i) were measured with UV laser scanning confocal ... More
Synthesis and characterization of dual-wavelength Cl--sensitive fluorescent indicators for ratio imaging.
AuthorsJayaraman S, Biwersi J, Verkman AS
JournalAm J Physiol
PubMed ID10070003
'The fluorescence of quinolinium-based Cl- indicators such as 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ) is quenched by Cl- by a collisional mechanism without change in spectral shape. A series of "chimeric" dual-wavelength Cl- indicators were synthesized by conjugating Cl--sensitive and -insensitive chromophores with spacers. The SPQ chromophore (N-substituted 6-methoxyquinolinium; MQ) was selected as the ... More
A concave fluorescent sensor for anions based on 6-methoxy-1-methylquinolinium.
AuthorsAmendola V, Fabbrizzi L, Monzani E
JournalChemistry
PubMed ID14695552
'The ligand 2, in which three fluorogenic 6-methoxy-1-methylquinolinium fragments are appended to a mesityl platform, in MeCN forms 1:1 adducts with halides and other inorganic anions. (1)H NMR studies and molecular modelling indicate that 2 provides a cavity for anion inclusion and establishes electrostatic interactions with the guest. Anion inclusion ... More
Effect of cAMP agonists on cell pH and anion transport by cultured rat inner medullary collecting duct cells.
AuthorsZhang C, Husted RF, Stokes JB
JournalAm J Physiol
PubMed ID8769831
'The rat inner medullary collecting duct is capable of secreting anions. We previously showed that adenosine 3'',5''-cyclic monophosphate (cAMP) stimulates anion secretion; the apical membrane anion exit pathway activated by cAMP appears to be the cystic fibrosis transmembrane conductance regulator Cl- channel. The present experiments were designed to test the ... More
The cholinergic antagonist alpha-bungarotoxin also binds and blocks a subset of GABA receptors.
AuthorsMcCann CM, Bracamontes J, Steinbach JH, Sanes JR
JournalProc Natl Acad Sci U S A
PubMed ID16549768
'The polypeptide snake toxin alpha-bungarotoxin (BTX) has been used in hundreds of studies on the structure, function, and development of the neuromuscular junction because it binds tightly and specifically to the nicotinic acetylcholine receptors (nAChRs) at this synapse. We show here that BTX also binds to and blocks a subset ... More
Fluorescence-optical measurements of chloride movements in cells using the membrane-permeable dye diH-MEQ.
AuthorsWöll E, Gschwentner M, Fürst J, Hofer S, Buemberger G, Jungwirth A, Frick J, Deetjen P, Paulmichl M
JournalPflugers Arch
PubMed ID8766008
'Fluorescence-optical measurements of the intracellular chloride concentration facilitate identification of chloride movements across the cell membrane of living cells. The two main dyes used for this purpose are 6-methoxy-N-(3-sulfopropyl)quinolinium (SPQ) and 6-methoxy-quinolyl acetoethyl ester (MQAE). The use of both substances is impaired by their poor membrane permeability and therefore limited ... More
A cluster of cytoplasmic histidine residues specifies pH dependence of the AE2 plasma membrane anion exchanger.
AuthorsSekler I, Kobayashi S, Kopito RR
JournalCell
PubMed ID8808628
Intracellular pH is maintained by a dynamic equilibrium balancing the opposing forces of proton loading and proton extrusion. By providing an efflux pathway for base, anion exchangers constitute a key component of the plasma membrane proton-loading machinery. The data in this paper identify a histidine-rich sequence within the cytoplasmic domain ... More
Selective role of intracellular chloride in the regulation of the intrinsic but not extrinsic pathway of apoptosis in Jurkat T-cells.
AuthorsHeimlich G, Cidlowski JA
JournalJ Biol Chem
PubMed ID16299378
Apoptosis is a genetic program for the removal of unwanted cells from an organism, which is distinct from necrosis by its characteristic volume loss or apoptotic volume decrease. This cell shrinkage is the result of ion redistribution that is crucial for both the activation and execution of apoptosis. Here we ... More
Optical imaging of intracellular chloride in living brain slices.
AuthorsSchwartz RD, Yu X
JournalJ Neurosci Methods
PubMed ID8750102
We developed an optical imaging technique to measure changes in intracellular levels of Cl- in neurons within the living brain slice. After rat brain slices were incubated with the permeant form of the Cl(-)-sensitive dye, 6-methoxy-N-ethylquinolinium chloride (MEQ), neurons could be imaged within the hippocampus, cerebral cortex and cerebellum using ... More
Cystic fibrosis phenotype associated with pancreatic insufficiency does not always reflect the cAMP-dependent chloride conductive pathway defect. Analysis of C225R-CFTR and R1066C-CFTR.
AuthorsFanen P, Labarthe R, Garnier F, Benharouga M, Goossens M, Edelman A
JournalJ Biol Chem
PubMed ID9374552
We have previously screened the cystic fibrosis transmembrane conductance regulator (CFTR) gene and identified new disease-causing mutations. C225R and R1066C are both associated with pancreatic insufficiency, but the former mutation is associated with mild and unusual lung disease, whereas the latter is associated with severe lung disease. In the present ... More
Cell-permeable fluorescent indicator for cytosolic chloride.
AuthorsBiwersi J, Verkman AS
JournalBiochemistry
PubMed ID1868062
A major limitation of quinolinium-based fluorescent indicators for cytosolic Cl- has been the necessity of invasive cell loading because the positively charged ring nitrogen confers high polarity and membrane impermeability. A novel approach to mask the positive nitrogen was developed and evaluated for rapid, noninvasive indicator loading into living cells ... More
Glycosylphosphatidylinositol-anchored proteins and actin cytoskeleton modulate chloride transport by channels formed by the Helicobacter pylori vacuolating cytotoxin VacA in HeLa cells.
AuthorsGauthier NC, Ricci V, Gounon P, Doye A, Tauc M, Poujeol P, Boquet P
JournalJ Biol Chem
PubMed ID14676190
The vacuolating cytotoxin VacA is an important virulence factor of Helicobacter pylori. Removing glycosylphosphatidylinositol-anchored proteins (GPI-Ps) from the cell surface by phosphatidylinositol-phospholipase C or disrupting the cell actin cytoskeleton by cytochalasin D reduced VacA-induced vacuolation of cells. Using the fluorescent dye 6-methoxy-N-ethylquinolinium chloride, an indicator for cytosolic chloride, we have ... More
Kinin-induced chloride permeability changes in colony 29 epithelia estimated from 125I- efflux and MEQ fluorescence.
AuthorsMacVinish LJ, Reancharoen T, Cuthbert AW
JournalBr J Pharmacol
PubMed ID8448597
1. The changes in apical Cl- permeability of Colony 29 human colonic epithelial monolayers were estimated from the rate constant of 125I- efflux from tissues loaded with the isotope. 2. Forskolin was used to increase intracellular concentrations of adenosine 3:5' cyclic-monophosphate (cyclic AMP), and A23187 to increase intracellular free Ca2+ ... More
Fluorescence imaging of changes in intracellular chloride in living brain slices.
AuthorsInglefield JR, Schwartz-Bloom RD
JournalMethods
PubMed ID10356351
In brain slice preparations, chloride movements across the cell membrane of living cells are measured traditionally with 36Cl- tracer methods, Cl--selective microelectrodes, or whole-cell recording using patch clamp analysis. We have developed an alternative, noninvasive technique that uses the fluorescent Cl- ion indicator, 6-methoxy-N-ethylquinolinium iodide (MEQ), to study changes in ... More
Activation of excitatory amino acid receptors in the rat hippocampal slice increases intracellular Cl- and cell volume.
AuthorsInglefield JR, Schwartz-Bloom RD
JournalJ Neurochem
PubMed ID9751170
The effects of glutamatergic excitotoxins on intracellular Cl- were investigated in the CA1 pyramidal cell layer of the hippocampal slice. Hippocampal slices from rats (14-19 days old) were loaded with 6-methoxy-N-ethylquinolinium chloride (MEQ), a Cl(-)-sensitive fluorescent probe with a fluorescence intensity that correlates inversely with intracellular [Cl-]. Slices were exposed ... More
Expression, localization, and functional evaluation of CFTR in bovine corneal endothelial cells.
AuthorsSun XC, Bonanno JA
JournalAm J Physiol Cell Physiol
PubMed ID11880256
HCO-dependent fluid secretion by the corneal endothelium controls corneal hydration and maintains corneal transparency. Recently, it has been shown that mRNA for the cystic fibrosis transmembrane conductance regulator (CFTR) is expressed in the corneal endothelium; however, protein expression, functional localization, and a possible role in HCO transport have not been ... More
Cultured insect mushroom body neurons express functional receptors for acetylcholine, GABA, glutamate, octopamine, and dopamine.
AuthorsCayre M, Buckingham SD, Yagodin S, Sattelle DB
JournalJ Neurophysiol
PubMed ID9914262
Fluorescence calcium imaging with fura-2 and whole cell, patch-clamp electrophysiology was applied to cultured Kenyon cells (interneurons) isolated from the mushroom bodies of adult crickets (Acheta domesticus) to demonstrate the presence of functional neurotransmitter receptors. In all cells investigated, 5 microM acetylcholine (ACh, n = 52) evoked an increase in ... More
Cell swelling stimulates cytosol to membrane transposition of ICln.
AuthorsRitter M, Ravasio A, Jakab M, Chwatal S, Fürst J, Laich A, Gschwentner M, Signorelli S, Burtscher C, Eichmüller S, Paulmichl M
JournalJ Biol Chem
PubMed ID12970357
ICln is a multifunctional protein that is essential for cell volume regulation. It can be found in the cytosol and is associated with the cell membrane. Besides its role in the splicing process, ICln is critically involved in the generation of ion currents activated during regulatory volume decrease after cell ... More
Shift of intracellular chloride concentration in ganglion and amacrine cells of developing mouse retina.
AuthorsZhang LL, Pathak HR, Coulter DA, Freed MA, Vardi N
JournalJ Neurophysiol
PubMed ID16371454
GABA and glycine provide excitatory action during early development: they depolarize neurons and increase intracellular calcium concentration. As neurons mature, GABA and glycine become inhibitory. This switch from excitation to inhibition is thought to result from a shift of intracellular chloride concentration ([Cl-]i) from high to low, but in retina, ... More
Regulation of intracellular Cl- concentration through volume-regulated ClC-3 chloride channels in A10 vascular smooth muscle cells.
AuthorsZhou JG, Ren JL, Qiu QY, He H, Guan YY
JournalJ Biol Chem
PubMed ID15596438
We previously found that antisense oligonucleotide specific to ClC-3 (ClC-3 antisense) prevented rat aortic smooth muscle cell proliferation, which was related to cell volume regulation. In the present study, we further characterized the regulation of intracellular Cl(-) concentrations ([Cl(-)](i)) via volume-regulated ClC-3 Cl(-) channels in an embryo rat aortic vascular ... More
NSP4 elicits age-dependent diarrhea and Ca(2+)mediated I(-) influx into intestinal crypts of CF mice.
AuthorsMorris AP, Scott JK, Ball JM, Zeng CQ, O'Neal WK, Estes MK
JournalAm J Physiol
PubMed ID10444458
Homologous disruption of the murine gene encoding the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) leads to the loss of cAMP-mediated ion transport. Mice carrying this gene defect exhibit meconium ileus at birth and gastrointestinal plugging during the neonatal period, both contributing to high rates of mortality. We investigated whether ... More
Modulation of glioma cell migration and invasion using Cl(-) and K(+) ion channel blockers.
AuthorsSoroceanu L, Manning TJ, Sontheimer H
JournalJ Neurosci
PubMed ID10407033
Human malignant gliomas are highly invasive tumors. Mechanisms that allow glioma cells to disseminate, migrating through the narrow extracellular brain spaces are poorly understood. We recently demonstrated expression of large voltage-dependent chloride (Cl(-)) currents, selectively expressed by human glioma cells in vitro and in situ (Ullrich et al., 1998). Currents ... More
Fluorescence imaging of GABAA receptor-mediated intracellular [Cl-] in P19-N cells reveals unique pharmacological properties.
AuthorsChistina Grobin A, Inglefield JR, Schwartz-Bloom RD, Devaud LL, Morrow AL
JournalBrain Res
PubMed ID10320687
This study describes the pharmacological properties of GABAA receptors expressed in P19-N cells using fluorescence imaging of intracellular chloride with 6-methoxy-N-ethylquinolinium iodide (MEQ). We show that application of the GABA agonist, muscimol (10-200 microM), produces time- and concentration-dependent increases in intracellular [Cl-] that are blocked by bicuculline. Diazepam (10 microM) ... More
Reciprocal interactions between calcium and chloride in rod photoreceptors.
AuthorsThoreson WB, Bryson EJ, Rabl K
JournalJ Neurophysiol
PubMed ID12724369
This study used imaging and electrophysiological techniques in salamander retinal slices to correlate Ca2+ and Cl- levels in rods and thus test the hypothesis of a feedback interaction between Ca2+- and Ca2+-activated Cl- channels whereby Cl- efflux through Cl- channels can inhibit Ca2+ channels. Increasing [K+]o levels produced a concentration-dependent ... More
AuthorsSun XC, Zhai CB, Cui M, Chen Y, Levin LR, Buck J, Bonanno JA
JournalAm J Physiol Cell Physiol
PubMed ID12519749
cAMP-dependent activation of the cystic fibrosis transmembrane conductance regulator (CFTR) regulates fluid transport in many tissues. Secretion by the corneal endothelium is stimulated by cAMP and dependent on HCO(3)(-). We asked whether HCO(3)(-) can secondarily increase CFTR permeability in bovine corneal endothelial cells (BCEC) by activating soluble adenylyl cyclase (sAC). ... More
CFTR modulates programmed cell death by decreasing intracellular pH in Chinese hamster lung fibroblasts.
AuthorsBarrière H, Poujeol C, Tauc M, Blasi JM, Counillon L, Poujeol P
JournalAm J Physiol Cell Physiol
PubMed ID11502558
To study the potential influence of cystic fibrosis conductance regulator (CFTR) on intracellular pH regulation during apoptosis induction, we used PS120 Chinese hamster lung fibroblasts devoid of the Na(+)/H(+) exchanger (NHE1 isoform) transfected with constructs, allowing the expression of CFTR and/or NHE1. Kinetics of lovastatin-induced apoptosis were measured by orcein ... More
Optical imaging reveals elevated intracellular chloride in hippocampal pyramidal neurons after oxidative stress.
AuthorsSah R, Schwartz-Bloom RD
JournalJ Neurosci
PubMed ID10531424
The accumulation of reactive oxygen species (ROS) in the brain is associated with several neurodegenerative conditions. ROS can affect ionic homeostasis leading to impaired neurotransmission. Here, we determined the ability of H(2)O(2), a membrane permeant ROS, to alter intraneuronal Cl(-), an important regulator of neuronal excitability. Real-time alterations in intracellular ... More
Chloride-sensitive MEQ fluorescence in chick embryo motoneurons following manipulations of chloride and during spontaneous network activity.
AuthorsChub N, Mentis GZ, O'donovan MJ
JournalJ Neurophysiol
PubMed ID16192339
Intracellular Cl(-) ([Cl(-)](in)) homeostasis is thought to be an important regulator of spontaneous activity in the spinal cord of the chick embryo. We investigated this idea by visualizing the variations of [Cl(-)](in) in motoneurons retrogradely labeled with the Cl-sensitive dye 6-methoxy-N-ethylquinolinium iodide (MEQ) applied to cut muscle nerves in the ... More