OSR1-sensitive regulation of Na+/H+ exchanger activity in dendritic cells

2012 ◽  
Vol 303 (4) ◽  
pp. C416-C426 ◽  
Author(s):  
Venkanna Pasham ◽  
Anand Rotte ◽  
Wenting Yang ◽  
Christine Zelenak ◽  
Madhuri Bhandaru ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dendritic Cells ◽  
Cell Volume ◽  
Cell Volume Regulation ◽  
Cell Swelling ◽  
Ros Production ◽  
Ros Formation ◽  
The Difference ◽  
And Migration ◽  
The Impact

The oxidative stress-responsive kinase 1 (OSR1) is activated by WNK (with no K kinases) and in turn stimulates the thiazide-sensitive Na-Cl cotransporter (NCC) and the furosemide-sensitive Na-K-2Cl cotransporter (NKCC), thus contributing to transport and cell volume regulation. Little is known about extrarenal functions of OSR1. The present study analyzed the impact of decreased OSR1 activity on the function of dendritic cells (DCs), antigen-presenting cells linking innate and adaptive immunity. DCs were cultured from bone marrow of heterozygous WNK-resistant OSR1 knockin mice ( osr KI) and wild-type mice ( osr WT). Cell volume was estimated from forward scatter in FACS analysis, ROS production from 2′,7′-dichlorodihydrofluorescein-diacetate fluorescence, cytosolic pH (pHi) from 2′,7′- bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein fluorescence, and Na+/H+ exchanger activity from Na+-dependent realkalinization following ammonium pulse and migration utilizing transwell chambers. DCs expressed WNK1, WNK3, NCC, NKCC1, and OSR1. Phosphorylated NKCC1 was reduced in osr KI DCs. Cell volume and pHi were similar in osr KI and osr WT DCs, but Na+/H+ exchanger activity and ROS production were higher in osr KI than in osr WT DCs. Before LPS treatment, migration was similar in osr KI and osr WT DCs. LPS (1 μg/ml), however, increased migration of osr WT DCs but not of osr KI DCs. Na+/H+ exchanger 1 inhibitor cariporide (10 μM) decreased cell volume, intracellular reactive oxygen species (ROS) formation, Na+/H+ exchanger activity, and pHi to a greater extent in osr KI than in osr WT DCs. LPS increased cell volume, Na+/H+ exchanger activity, and ROS formation in osr WT DCs but not in osr KI DCs and blunted the difference between osr KI and osr WT DCs. Na+/H+ exchanger activity in osr WT DCs was increased by the NKCC1 inhibitor furosemide (100 nM) to values similar to those in osr KI DCs. Oxidative stress (10 μM tert-butyl-hydroperoxide) increased Na+/H+ exchanger activity in osr WT DCs but not in osr KI DCs and reversed the difference between genotypes. Cariporide virtually abrogated Na+/H+ exchanger activity in both genotypes and blunted LPS-induced cell swelling and ROS formation in osr WT mice. In conclusion, partial OSR1 deficiency influences Na+/H+ exchanger activity, ROS formation, and migration of dendritic cells.

scholarly journals Acid- and Volume-Sensitive Chloride Currents in Microglial Cells

2019 ◽  
Vol 20 (14) ◽  
pp. 3475 ◽  
Author(s):  
Michael Kittl ◽  
Katharina Helm ◽  
Marlena Beyreis ◽  
Christian Mayr ◽  
Martin Gaisberger ◽  
...  
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Cell Types ◽  
Microglial Cells ◽  
Cell Swelling ◽  
Mean Cell Volume ◽  
Current Activation ◽  
And Migration

Many cell types express an acid-sensitive outwardly rectifying (ASOR) anion current of an unknown function. We characterized such a current in BV-2 microglial cells and then studied its interrelation with the volume-sensitive outwardly rectifying (VSOR) Cl− current and the effect of acidosis on cell volume regulation. We used patch clamp, the Coulter method, and the pH-sensitive dye BCECF to measure Cl− currents and cell membrane potentials, mean cell volume, and intracellular pH, respectively. The ASOR current activated at pH ≤ 5.0 and displayed an I− > Cl− > gluconate− permeability sequence. When compared to the VSOR current, it was similarly sensitive to DIDS, but less sensitive to DCPIB, and insensitive to tamoxifen. Under acidic conditions, the ASOR current was the dominating Cl− conductance, while the VSOR current was apparently inactivated. Acidification caused cell swelling under isotonic conditions and prevented the regulatory volume decrease under hypotonicity. We conclude that acidification, associated with activation of the ASOR- and inactivation of the VSOR current, massively impairs cell volume homeostasis. ASOR current activation could affect microglial function under acidotoxic conditions, since acidosis is a hallmark of pathophysiological events like inflammation, stroke or ischemia and migration and phagocytosis in microglial cells are closely related to cell volume regulation.

scholarly journals Proximal tubule volume regulation in hypo-osmotic media: intracellular K+, Na+, and Cl-.

1990 ◽  
Vol 1 (2) ◽  
pp. 211-218
Author(s):  
L Rome ◽  
C Lechene ◽  
J J Grantham
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Cell Volume Regulation ◽  
Rabbit Kidney ◽  
Kidney Cortex ◽  
Volume Regulatory Decrease ◽  
Osmotic Change ◽  
Electrolyte Loss ◽  
The Difference

This study sought to measure the net loss of intracellular K+, Na+, and Cl- that accompanied isosmotic cell volume regulation in hypotonic media and to determine if electrolyte loss depended on the rate at which the extracellular osmolality was reduced. Isolated nonperfused proximal S2 segments from rabbit kidney cortex were studied in vitro. Gradual lowering of osmolality from 295 to 150 mOsm/kg at a rate of 2 mOsm/kg/min did not cause an increase in tubule cell volume until the medium osmolality decreased below 190 mOsm/kg. By contrast, tubules rapidly bathed in low osmolality media exhibited classical osmometric swelling followed by incomplete volume regulatory decrease. Volume regulation associated with gradual and rapid lowering of osmolality was accompanied by the net loss of intracellular K+, Na+, and Cl- (measured by electron probe); however, the temporal pattern of electrolyte loss depended on the rate of osmotic change. With gradual lowering of osmolality, cell K+ content did not decrease significantly until osmolality was lowered below 200 mOsm/kg, whereas Cl- was lost at the 200 mOsm/kg level and below. With rapid lowering of osmolality, cell K+ content was strikingly decreased at the 200 mOsm/kg level, but Cl- did not change appreciably until osmolality was decreased to 150 mOsm/kg. Cell Na+ content decreased in hypo-osmotic media, but the magnitude was relatively small. During volume regulation that accompanied either gradual or rapid lowering of medium osmolality from 295 to 150 mOsm/kg, intracellular osmolal gap, the difference between medium osmolality and the sum of intracellular concentrations of K+, Na+, and Cl- decreased 87 and 58 mOsm/kg, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Dihydropyridine-sensitive cell volume regulation in proximal tubule: the calcium window

1990 ◽  
Vol 259 (6) ◽  
pp. F950-F960 ◽  
Author(s):  
N. A. McCarty ◽  
R. G. O'Neil
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Cell Swelling ◽  
Channel Blockers ◽  
Ca Channel ◽  
Hypotonic Solution ◽  
Dependent Manner ◽  
Intracellular Ca

The mechanism underlying the activation of hypotonic cell volume regulation was studied in rabbit proximal straight tubule (PST). When isolated non-perfused tubules were exposed to hypotonic solution, cells swelled rapidly and then underwent a regulatory volume decrease (RVD). The extent of regulation after swelling was highly dependent on extracellular Ca concentration ([Ca2+]o), with a half-maximal inhibition (K1/2) for [Ca2+]o of approximately 100 microM. RVD was blocked by the Ca-channel blockers verapamil, lanthanum, and the dihydropyridines (DHP) nifedipine and nitrendipine, implicating voltage-activated Ca channels in the RVD response. Using the fura-2 fluorescence-ratio technique, we observed that cell swelling caused a sustained rise in intracellular Ca ([Ca2+]i) only when [Ca2+]o was normal (1 mM) but not when [Ca2+]o was low (1-10 microM). Furthermore, external Ca was required early on during swelling to induce RVD. If RVD was initially blocked by reducing [Ca2+]o or by addition of verapamil during hypotonic swelling, volume regulation could only be restored by subsequently inducing Ca entry within the first 1 min or less of exposure to hypotonic solution. These data indicate a "calcium window" of less than 1 min, during which RVD is sensitive to Ca, and that part of the Ca-dependent mechanism responsible for achieving RVD undergoes inactivation after swelling. It is concluded that RVD in rabbit PST is modulated by Ca via a DHP-sensitive mechanism in a time-dependent manner.

scholarly journals Molecular Changes Induced by Oxidative Stress that Impair Human Sperm Motility

Antioxidants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 134 ◽  
Author(s):  
Karolina Nowicka-Bauer ◽  
Brett Nixon
Keyword(s):  
Oxidative Stress ◽  
Sperm Motility ◽  
Reproductive Tract ◽  
Therapeutic Interventions ◽  
Antioxidant Defenses ◽  
Ros Production ◽  
Paternal Genome ◽  
Male Reproductive Tract ◽  
Ability To Act ◽  
The Impact

A state of oxidative stress (OS) and the presence of reactive oxygen species (ROS) in the male reproductive tract are strongly correlated with infertility. While physiological levels of ROS are necessary for normal sperm functioning, elevated ROS production can overwhelm the cell’s limited antioxidant defenses leading to dysfunction and loss of fertilizing potential. Among the deleterious pleiotropic impacts arising from OS, sperm motility appears to be particularly vulnerable. Here, we present a mechanistic account for how OS contributes to altered sperm motility profiles. In our model, it is suggested that the abundant polyunsaturated fatty acids (PUFAs) residing in the sperm membrane serve to sensitize the male germ cell to ROS attack by virtue of their ability to act as substrates for lipid peroxidation (LPO) cascades. Upon initiation, LPO leads to dramatic remodeling of the composition and biophysical properties of sperm membranes and, in the case of the mitochondria, this manifests in a dissipation of membrane potential, electron leakage, increased ROS production and reduced capacity for energy production. This situation is exacerbated by the production of cytotoxic LPO byproducts such as 4-hydroxynonenal, which dysregulate molecules associated with sperm bioenergetic pathways as well as the structural and signaling components of the motility apparatus. The impact of ROS also extends to lesions in the paternal genome, as is commonly seen in the defective spermatozoa of asthenozoospermic males. Concluding, the presence of OS in the male reproductive tract is strongly and positively correlated with reduced sperm motility and fertilizing potential, thus providing a rational target for the development of new therapeutic interventions.

Endogenous ATP release regulates Cl− secretion in cultured human and rat biliary epithelial cells

1999 ◽  
Vol 276 (6) ◽  
pp. G1391-G1400 ◽  
Author(s):  
Richard M. Roman ◽  
Andrew P. Feranchak ◽  
Kelli D. Salter ◽  
Yu Wang ◽  
J. Gregory Fitz
Keyword(s):  
Epithelial Cells ◽  
Cell Volume ◽  
Purinergic Signaling ◽  
Cell Volume Regulation ◽  
Atp Release ◽  
Extracellular Atp ◽  
Extracellular Nucleotides ◽  
Cell Swelling ◽  
Biliary Epithelial Cells ◽  
Normal Rat

P2Y receptor stimulation increases membrane Cl− permeability in biliary epithelial cells, but the source of extracellular nucleotides and physiological relevance of purinergic signaling to biliary secretion are unknown. Our objectives were to determine whether biliary cells release ATP under physiological conditions and whether extracellular ATP contributes to cell volume regulation and transepithelial secretion. With the use of a sensitive bioluminescence assay, constitutive ATP release was detected from human Mz-ChA-1 cholangiocarcinoma cells and polarized normal rat cholangiocyte monolayers. ATP release increased rapidly during cell swelling induced by hypotonic exposure. In Mz-ChA-1 cells, removal of extracellular ATP (apyrase) and P2 receptor blockade (suramin) reversibly inhibited whole cell Cl− current activation and prevented cell volume recovery during hypotonic stress. Moreover, exposure to apyrase induced cell swelling under isotonic conditions. In intact normal rat cholangiocyte monolayers, hypotonic perfusion activated apical Cl−currents, which were inhibited by addition of apyrase and suramin to bathing media. These findings indicate that modulation of ATP release by the cellular hydration state represents a potential signal coordinating cell volume with membrane Cl− permeability and transepithelial Cl−secretion.

scholarly journals Regulation of Na+/H+ Exchanger in Dendritic Cells by Akt1

2015 ◽  
Vol 36 (3) ◽  
pp. 1237-1249 ◽  
Author(s):  
Yuetao Zhou ◽  
Venkanna Pasham ◽  
Soumya Chatterjee ◽  
Anand Rotte ◽  
Wenting Yang ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Primary Immune Response ◽  
Cytosolic Ph ◽  
Forward Scatter ◽  
Akt Phosphorylation ◽  
Tert Butylhydroperoxide ◽  
Ros Formation ◽  
Bacterial Lipopolysaccharides ◽  
And Migration ◽  
Stimulation Of

Background/Aims: Dendritic cells (DCs), antigen-presenting cells critically important for primary immune response and establishment of immunological memory, are activated by bacterial lipopolysaccharides (LPS) resulting in stimulation of Na+/H+ exchanger, ROS formation and migration. The effects are dependent on phosphoinositide 3 (PI3) kinase and paralleled by Akt phosphorylation. The present study explored the contribution of the Akt isoform Akt1. Methods: Cytosolic pH (pHi) (2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein [BCECF] fluorescence), Na+/H+ exchanger activity (Na+ dependent realkalinization after an ammonium pulse), cell volume (forward scatter in FACS analysis), and ROS production (2′,7′-dichlorodihydrofluorescein diacetate [DCFDA] fluorescence) were determined in DCs isolated from bone marrow of mice lacking functional Akt1/PKBα (akt1-/-) and their wild type littermates (akt1+/+). Results: Forward scatter was lower in akt1-/- than in akt1+/+ DCs, whereas pHi, Na+/H+ exchanger activity and ROS formation were less in untreated akt1-/- and akt1+/+ DCs. Exposure of DCs to LPS was followed by increase of forward scatter and ROS formation to a similar extent in akt1-/- and in akt1+/+ DCs. A 4 hours treatment with either LPS (1µg/ml) or tert-butylhydroperoxide (tBOOH, 5 µM) significantly stimulated Na+/H+ exchanger activity in both genotypes, effects, however, significantly blunted in akt1-/- DCs. Conclusion: The present observations demonstrate that Akt1 is required for the full stimulation of Na+/H+ exchanger activity by LPS or oxidative stress in dendritic cells.

scholarly journals Interactions of sodium transport, cell volume, and calcium in frog urinary bladder.

1987 ◽  
Vol 89 (5) ◽  
pp. 687-702 ◽  
Author(s):  
C W Davis ◽  
A L Finn
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Apical Membrane ◽  
Basolateral Membrane ◽  
Cell Volume Regulation ◽  
Positive Control ◽  
Negative Control ◽  
Cell Swelling ◽  
Ionophore A23187 ◽  
Intracellular Ca

The volume of individual cells in intact frog urinary bladders was determined by quantitative microscopy and changes in volume were used to monitor the movement of solute across the basolateral membrane. When exposed to a serosal hyposmotic solution, the cells swell as expected for an osmometer, but then regulate their volume back to near control in a process that involves the loss of KCl. We show here that volume regulation is abolished by Ba++, which suggests that KCl movements are mediated by conductive channels for both ions. Volume regulation is also inhibited by removing Ca++ from the serosal perfusate, which suggests that the channels are activated by this cation. Previously, amiloride was observed to inhibit volume regulation: in this study, amiloride-inhibited, hyposmotically swollen cells lost volume when the Ca++ ionophore A23187 was added to Ca++-replete media. We attempted to effect volume changes under isosmotic conditions by suddenly inhibiting Na+ entry across the apical membrane with amiloride, or Na+ exit across the basolateral membrane with ouabain. Neither of these Na+ transport inhibitors produced the expected results. Amiloride, instead of causing a decrease in cell volume, had no effect, and ouabain, instead of causing cell swelling, caused cell shrinkage. However, increasing cell Ca++ with A23187, in both the absence and presence of amiloride, caused cells to lose volume, and Ca++-free Ringer's solution (serosal perfusate only) caused ouabain-blocked cells to swell. Finally, again under isosmotic conditions, removal of Na+ from the serosal perfusate caused a loss of volume from cells exposed to amiloride. These results strongly suggest that intracellular Ca++ mediates cell volume regulation by exerting a negative control on apical membrane Na+ permeability and a positive control on basolateral membrane K+ permeability. They also are compatible with the existence of a basolateral Na+/Ca++ exchanger.

scholarly journals Cell Death Induction and Protection by Activation of Ubiquitously Expressed Anion/Cation Channels. Part 2: Functional and Molecular Properties of ASOR/PAC Channels and Their Roles in Cell Volume Dysregulation and Acidotoxic Cell Death

2021 ◽  
Vol 9 ◽  
Author(s):  
Yasunobu Okada ◽  
Kaori Sato-Numata ◽  
Ravshan Z. Sabirov ◽  
Tomohiro Numata
Keyword(s):  
Cell Death ◽  
Cell Volume ◽  
Apoptotic Cell ◽  
Cell Volume Regulation ◽  
Anion Channel ◽  
Cell Swelling ◽  
Dimensional Structure ◽  
Cation Channels ◽  
Anion Channels ◽  
Animal Cells

For survival and functions of animal cells, cell volume regulation (CVR) is essential. Major hallmarks of necrotic and apoptotic cell death are persistent cell swelling and shrinkage, and thus they are termed the necrotic volume increase (NVI) and the apoptotic volume decrease (AVD), respectively. A number of ubiquitously expressed anion and cation channels play essential roles not only in CVR but also in cell death induction. This series of review articles address the question how cell death is induced or protected with using ubiquitously expressed ion channels such as swelling-activated anion channels, acid-activated anion channels, and several types of TRP cation channels including TRPM2 and TRPM7. In the Part 1, we described the roles of swelling-activated VSOR/VRAC anion channels. Here, the Part 2 focuses on the roles of the acid-sensitive outwardly rectifying (ASOR) anion channel, also called the proton-activated chloride (PAC) anion channel, which is activated by extracellular protons in a manner sharply dependent on ambient temperature. First, we summarize phenotypical properties, the molecular identity, and the three-dimensional structure of ASOR/PAC. Second, we highlight the unique roles of ASOR/PAC in CVR dysfunction and in the induction of or protection from acidotoxic cell death under acidosis and ischemic conditions.

Potassium-induced cell swelling in Necturus gallbladder epithelium

1988 ◽  
Vol 254 (5) ◽  
pp. C643-C650 ◽  
Author(s):  
C. W. Davis ◽  
A. L. Finn
Keyword(s):  
Cell Volume ◽  
Volume Regulation ◽  
Basolateral Membrane ◽  
Cell Volume Regulation ◽  
Cell Swelling ◽  
Gallbladder Epithelium ◽  
Bathing Medium ◽  
Necturus Gallbladder ◽  
Per Se ◽  
Cl Conductance

In Necturus gallbladder epithelium, elevation of mucosal K+ to 95 mM in the presence of 10 mM Na+ resulted in cell swelling at a rate of 3.2% original volume per minute, followed by volume-regulatory shrinking. When Na+ was completely removed from or when amiloride (10(-4) M) was added to the mucosal medium, K+-induced cell swelling was abolished. In the presence of 10 mM Na+, 1 mM Ba2+ abolished and substitution of mucosal Cl- by NO-3 had no effect on K+-induced swelling. Thus solute entry following elevation of mucosal K+ is effected by separate K+ and Cl- pathways. Furthermore, substitution of 95 mM K+ for Na+ in the mucosal bathing medium leads to the development of a Cl- conductance in the basolateral membrane as long as some Na+ remains in the medium. However, cell swelling induced by mucosal dilution does not lead to the appearance of a Cl- conductance. Thus the activation of this conductance requires both swelling and membrane depolarization. These results show that 1) high mucosal K+ leads to cell swelling due to the entry of Cl- along with K+ and the Cl- can enter across either membrane, 2) the Cl- pathways require the presence of mucosal Na+, and 3) cell volume regulation is activated by an increase in volume per se, i.e., a hyposmotic exposure is not required for volume regulation to occur.

scholarly journals Indirect Role of AQP4b and AQP4d Isoforms in Dynamics of Astrocyte Volume and Orthogonal Arrays of Particles

Cells ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 735 ◽  
Author(s):  
Marjeta Lisjak ◽  
Maja Potokar ◽  
Robert Zorec ◽  
Jernej Jorgačevski
Keyword(s):  
Plasma Membrane ◽  
Cell Volume ◽  
Volume Regulation ◽  
Water Channel ◽  
Regulatory Volume Decrease ◽  
Cell Volume Regulation ◽  
Orthogonal Arrays ◽  
Cell Swelling ◽  
Early Endosomes ◽  
Orthogonal Arrays Of Particles

Water channel aquaporin 4 (AQP4) plays a key role in the regulation of water homeostasis in the central nervous system (CNS). It is predominantly expressed in astrocytes lining blood–brain and blood–liquor boundaries. AQP4a (M1), AQP4c (M23), and AQP4e, present in the plasma membrane, participate in the cell volume regulation of astrocytes. The function of their splicing variants, AQP4b and AQP4d, predicted to be present in the cytoplasm, is unknown. We examined the cellular distribution of AQP4b and AQP4d in primary rat astrocytes and their role in cell volume regulation. The AQP4b and AQP4d isoforms exhibited extensive cytoplasmic localization in early and late endosomes/lysosomes and in the Golgi apparatus. Neither isoform localized to orthogonal arrays of particles (OAPs) in the plasma membrane. The overexpression of AQP4b and AQP4d isoforms in isoosmotic conditions reduced the density of OAPs; in hypoosmotic conditions, they remained absent from OAPs. In hypoosmotic conditions, the AQP4d isoform was significantly redistributed to early endosomes, which correlated with the increased trafficking of AQP4-laden vesicles. The overexpression of AQP4d facilitated the kinetics of cell swelling, without affecting the regulatory volume decrease. Therefore, although they reside in the cytoplasm, AQP4b and AQP4d isoforms may play an indirect role in astrocyte volume changes.

Sign in / Sign up

Export Citation Format

Share Document