scholarly journals Pendrin Overexpression Affects Cell Volume Recovery, Intracellular pH and Chloride Concentration after Hypotonicity-induced Cell Swelling

2011 ◽  
Vol 28 (3) ◽  
pp. 559-570 ◽  
Author(s):  
Simona Rodighiero ◽  
Guido Bottà ◽  
Claudia Bazzini ◽  
Giuliano Meyer
Keyword(s):  
Cell Volume ◽  
Intracellular Ph ◽  
Chloride Concentration ◽  
Cell Swelling ◽  
Volume Recovery

Regulation of cell volume and intracellular pH in hyposmotically swollen rat osteosarcoma cells

1995 ◽  
Vol 73 (7-8) ◽  
pp. 535-544 ◽  
Author(s):  
C. Lo ◽  
J. Ferrier ◽  
H. C. Tenenbaum ◽  
C. A. G. McCulloch
Keyword(s):  
Cell Volume ◽  
Intracellular Ph ◽  
Binding Proteins ◽  
Kinase Inhibitor ◽  
Regulatory Volume Decrease ◽  
Cell Swelling ◽  
Osteosarcoma Cells ◽  
Extracellular Medium ◽  
Gtp Binding Proteins ◽  
Gtp Binding

The maintenance of cell volume involves transduction of a volume-sensing signal into effectors of volume-regulatory transporters. After exposure to anisotonic conditions, cells undergo compensatory volume changes that are mediated by active transport and passive movement of ions and solutes. Intracellular pH (pHi) homeostasis may be compromised during these processes. We have studied pHi and some of the signal transduction mechanisms involved in the regulatory volume decrease (RVD) that occurs after exposure to hypoosmolar conditions in rat osteosarcoma cells, ROS 17/2.8. Cells were loaded with BCECF; pHi and cell volume were estimated by dual excitation ratio fluorimetry. Swelling of cells in 4-(2-hydroxyethyl)-l-piperazineethanesulfonic acid (HEPES) buffered hypotonic medium induced a rapid cell swelling followed by an incomplete RVD of ~30% in suspended (i.e., round) cells and ~60% in attached (i.e., spread) cells that was independent of subpassage number. RVD was inhibited by ouabain, valinomycin, and high external [K+], all of which should reduce the cell membrane electrochemical gradient for K+. Inhibition of RVD was induced also by decreasing intracellular [Ca2+] with B APTA–AM and by depletion of Cl−, indicating the role of calcium-regulated K+ and Cl− efflux during RVD. Depolymerization of actin filaments by cytochalasin D prolonged the RVD three-fold and nonspecific activation of GTP-binding proteins up-regulated RVD. In attached cells the hypoosmolar-induced swelling caused a large reduction in pHi (~0.7 units), which was sustained as long as cells were in hypoosmotic medium. The reduction of pHi induced by cell swelling was inhibited by Na+-free extracellular medium, ouabain, the tyrosine kinase inhibitor genistein, and to a lesser extent by Cl−-free medium. However, amiloride failed to inhibit the hypoosmolar-induced reduction of pHi. Collectively these data indicate that RVD of ROS 17/2.8 cells in HEPES-buffered medium is dependent on conductive efflux of K+ and Cl− that is regulated by cell shape, actin, and GTP-binding proteins. The sustained inhibition of pHi homeostasis induced by cell swelling may reflect the existence of cell volume sensing mechanisms that operate through tyrosine kinases to regulate pHi.Key words: cell volume, pH, osteoblast, G proteins, actin.

scholarly journals WNK3 and WNK4 exhibit opposite sensitivity with respect to cell volume and intracellular chloride concentration

2020 ◽  
Vol 319 (2) ◽  
pp. C371-C380
Author(s):  
Diana Pacheco-Alvarez ◽  
Diego Luis Carrillo-Pérez ◽  
Adriana Mercado ◽  
Karla Leyva-Ríos ◽  
Erika Moreno ◽  
...  
Keyword(s):  
Cell Volume ◽  
Chloride Concentration ◽  
Cell Swelling ◽  
Cell Shrinkage ◽  
Serine Threonine Kinase ◽  
Intracellular Chloride ◽  
Highly Sensitive ◽  
A Cell ◽  
Carboxy Terminal ◽  
Intracellular Chloride Concentration

Cation-coupled chloride cotransporters (CCC) play a role in modulating intracellular chloride concentration ([Cl−]i) and cell volume. Cell shrinkage and cell swelling are accompanied by an increase or decrease in [Cl−]i, respectively. Cell shrinkage and a decrease in [Cl−]i increase the activity of NKCCs (Na-K-Cl cotransporters: NKCC1, NKCC2, and Na-Cl) and inhibit the activity of KCCs (K-Cl cotransporters: KCC1 to KCC4), wheras cell swelling and an increase in [Cl−]i activate KCCs and inhibit NKCCs; thus, it is unlikely that the same kinase is responsible for both effects. WNK1 and WNK4 are chloride-sensitive kinases that modulate the activity of CCC in response to changes in [Cl−]i. Here, we showed that WNK3, another member of the serine-threonine kinase WNK family with known effects on CCC, is not sensitive to [Cl−]i but can be regulated by changes in extracellular tonicity. In contrast, WNK4 is highly sensitive to [Cl−]i but is not regulated by changes in cell volume. The activity of WNK3 toward NaCl cotransporter is not affected by eliminating the chloride-binding site of WNK3, further confirming that the kinase is not sensitive to chloride. Chimeric WNK3/WNK4 proteins were produced, and analysis of the chimeras suggests that sequences within the WNK’s carboxy-terminal end may modulate the chloride affinity. We propose that WNK3 is a cell volume-sensitive kinase that translates changes in cell volume into phosphorylation of CCC.

Loss of cell volume regulation during metabolic inhibition in renal epithelial cells (A6): role of intracellular pH

2002 ◽  
Vol 283 (2) ◽  
pp. C535-C544 ◽  
Author(s):  
Ilse Smets ◽  
Marcel Ameloot ◽  
Paul Steels ◽  
Willy Van Driessche
Keyword(s):  
Epithelial Cells ◽  
Cell Volume ◽  
Intracellular Ph ◽  
Volume Regulation ◽  
Metabolic Inhibition ◽  
Cell Swelling ◽  
Intracellular Acidification ◽  
Hypotonic Shock ◽  
A6 Cells ◽  
External Ph

In renal ischemia, tubular obstruction induced by swelling of epithelial cells might be an important mechanism for reduction of the glomerular filtration rate. We investigated ischemic cell swelling by examining volume regulation of A6 cells during metabolic inhibition (MI) induced by cyanide and 2-deoxyglucose. Changes in cell volume were monitored by recording cell thickness ( T c). Intracellular pH (pHc) measurements were performed with the pH-sensitive probe 5-chloromethyl-fluoresceine diacetate. T c measurements showed that MI increases cell volume. Cell swelling during MI is proportional to the rate of Na+ transport and is not followed by a volume regulatory response. Furthermore, MI prevents the regulatory volume decrease (RVD) elicited by a hyposmotic shock. MI induces a pronounced intracellular acidification that is conserved during a subsequent hypotonic shock. A transient acidification induced by a NH4Cl prepulse causes a marked delay of the RVD in response to a hypotonic shock. On the other hand, acute lowering of external pH to 5, simultaneously with the hypotonic shock, allowed the onset of RVD. However, this RVD was completely arrested ∼10 min after the initiation of the hyposmotic challenge. The inhibition of RVD appears to be related to the pronounced acidification that occurred within this time period. In contrast, when external pH was lowered 20 min before the hyposmotic shock, RVD was absent. These data suggest that internal acidification inhibits cellular volume regulation in A6 cells. Therefore, the intracellular acidification associated with MI might at least partly account for the failure of volume regulation in swollen epithelial cells.

scholarly journals Myosin light chain kinase and Src control membrane dynamics in volume recovery from cell swelling

2011 ◽  
Vol 22 (5) ◽  
pp. 634-650 ◽  
Author(s):  
Elisabeth T. Barfod ◽  
Ann L. Moore ◽  
Benjamin G. Van de Graaf ◽  
Steven D. Lidofsky
Keyword(s):  
Cell Volume ◽  
Light Chain ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Myosin Ii ◽  
Membrane Dynamics ◽  
Cell Swelling ◽  
Membrane Turnover ◽  
Osmotic Swelling ◽  
Volume Recovery

 The expansion of the plasma membrane, which occurs during osmotic swelling of epithelia, must be retrieved for volume recovery, but the mechanisms are unknown. Here we have identified myosin light chain kinase (MLCK) as a regulator of membrane internalization in response to osmotic swelling in a model liver cell line. On hypotonic exposure, we found that there was time-dependent phosphorylation of the MLCK substrate myosin II regulatory light chain. At the sides of the cell, MLCK and myosin II localized to swelling-induced membrane blebs with actin just before retraction, and MLCK inhibition led to persistent blebbing and attenuated cell volume recovery. At the base of the cell, MLCK also localized to dynamic actin-coated rings and patches upon swelling, which were associated with uptake of the membrane marker FM4-64X, consistent with sites of membrane internalization. Hypotonic exposure evoked increased biochemical association of the cell volume regulator Src with MLCK and with the endocytosis regulators cortactin and dynamin, which colocalized within these structures. Inhibition of either Src or MLCK led to altered patch and ring lifetimes, consistent with the concept that Src and MLCK form a swelling-induced protein complex that regulates volume recovery through membrane turnover and compensatory endocytosis under osmotic stress.

Regulation of cell function by the cellular hydration state

1994 ◽  
Vol 267 (3) ◽  
pp. E343-E355 ◽  
Author(s):  
D. Haussinger ◽  
F. Lang ◽  
W. Gerok
Keyword(s):  
Cell Volume ◽  
Cell Function ◽  
Narrow Range ◽  
Cell Swelling ◽  
Metabolic Function ◽  
Cell Shrinkage ◽  
Short Term ◽  
Hydration State ◽  
Per Se ◽  
And Oxidative Stress

Cellular hydration can change within minutes under the influence of hormones, nutrients, and oxidative stress. Such short-term modulation of cell volume within a narrow range acts per se as a potent signal which modifies cellular metabolism and gene expression. It appears that cell swelling and cell shrinkage lead to certain opposite patterns of cellular metabolic function. Apparently, hormones and amino acids can trigger those patterns simply by altering cell volume. Thus alterations of cellular hydration may represent another important mechanism for metabolic control and act as another second or third messenger linking cell function to hormonal and environmental alterations.

scholarly journals The ionic basis of the hypo-osmotic depolarization in neurons from the opisthobranch mollusc Elysia chlorotica

1992 ◽  
Vol 163 (1) ◽  
pp. 169-186
Author(s):  
R. H. Quinn ◽  
S. K. Pierce
Keyword(s):  
Cell Volume ◽  
Time Course ◽  
The Other ◽  
Resting Potential ◽  
Ion Concentrations ◽  
Elysia Chlorotica ◽  
Apparent Relationship ◽  
Volume Recovery ◽  
Original Potential ◽  
Ionic Basis

The resting potential of identified cells (Parker cells) in the abdominal ganglion of Elysia chlorotica (Gould) depolarizes by about 30 mV in response to a 50% reduction in osmolality and returns to the original potential in 20 min. Cell volume recovery requires approximately 2 h. Thus, recovery of the resting potential is not dependent on recovery of cell volume. The hypo-osmotic depolarization persists following inhibition of the electrogenic Na+/K(+)-ATPase with ouabain, and the levels of extracellular K+ and Cl- have little effect on the magnitude of the depolarization, while decreasing extracellular Na+ concentration produces a depolarization of only 10 mV. This suggests that the hypo-osmotic depolarization in Parker cells results mostly from increased relative permeability to Na+. Following transfer from 920 to 460 mosmol kg-1, Na+, Cl- and proline betaine leave the cells while intracellular K+ is conserved. Loss of intracellular Na+ and conservation of intracellular K+ are dependent on active transport by the Na+/K(+)-ATPase. Na+ and proline betaine leave the cells with a time course that is much longer than that of the hypo-osmotic depolarization. Unlike the other solutes, most of the reduction in intracellular Cl- concentration occurs coincidentally with the hypo-osmotic depolarization. However, unlike the hypo-osmotic depolarization, bulk loss of Cl- does not require the reduction in osmolality, only the reduction in extracellular ion concentrations. There is no apparent relationship between membrane depolarization and the regulation of intracellular osmolytes in Elysia neurons following hypo-osmotic stress.

scholarly journals Intracellular free calcium oscillates during cell division of Xenopus embryos.

1991 ◽  
Vol 112 (4) ◽  
pp. 711-718 ◽  
Author(s):  
N Grandin ◽  
M Charbonneau
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Volume ◽  
Intracellular Ph ◽  
Calcium Ions ◽  
Volume Ratio ◽  
Mean Amplitude ◽  
Free Calcium ◽  
Periodic Oscillations ◽  
Xenopus Embryos

In Xenopus embryos, previous results failed to detect changes in the activity of free calcium ions (Ca2+i) during cell division using Ca2(+)-selective microelectrodes, while experiments with aequorin yielded uncertain results complicated by the variation during cell division of the aequorin concentration to cell volume ratio. We now report, using Ca2(+)-selective microelectrodes, that cell division in Xenopus embryos is accompanied by periodic oscillations of the Ca2+i level, which occur with a periodicity of 30 min, equal to that of the cell cycle. These Ca2+i oscillations were detected in 24 out of 35 experiments, and had a mean amplitude of 70 nM, around a basal Ca2+i level of 0.40 microM. Ca2+i oscillations did not take place in the absence of cell division, either in artificially activated eggs or in cleavage-blocked embryos. Therefore, Ca2+i oscillations do not represent, unlike intracellular pH oscillations (Grandin, N., and M. Charbonneau. J. Cell Biol. 111:523-532. 1990), a component of the basic cell cycle ("cytoplasmic clock" or "master oscillator"), but appear to be more likely related to some events of mitosis.

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.

Coupled NaCl entry into Necturus gallbladder epithelial cells

1982 ◽  
Vol 243 (3) ◽  
pp. C140-C145 ◽  
Author(s):  
A. C. Ericson ◽  
K. R. Spring
Keyword(s):  
Epithelial Cells ◽  
Cell Volume ◽  
Apical Membrane ◽  
Ionic Composition ◽  
Basolateral Membrane ◽  
Cell Swelling ◽  
Disulfonic Acid ◽  
Bathing Solution ◽  
Parallel Operation ◽  
Solute Content

NaCl entry into Necturus maculosus gallbladder epithelial cells was studied by determination of the rate of fluid movement into the cell when the Na+-K+-ATPase was inhibited by 10(-4) M ouabain in the serosal bathing solution. The cell swelling was due to continuing entrance of NaCl into the cell across the apical membrane, which increased the solute content of the cell; the resultant rise in cell osmolality induced water flow and cell swelling. The rate of swelling was 4.3% of the cell volume per minute, equivalent to a volume flow across the apical membrane of 1.44 x 10(-6) cm/s, similar in magnitude to the normal rate of fluid absorption by the gallbladder. We determined the mechanism of NaCl entry by varying the ionic composition of the mucosal bath; when most of the mucosal Na+ or Cl- was replaced, cell volume did not increase during pump inhibition. The rate of NaCl entry was a saturable function of Na+ or Cl- in the mucosal bathing solution with K1/2 values of 26.6 mM for Na+ and 19.5 mM for Cl-. The mode of NaCl entry was probably not the parallel operation of Na+-H+ and Cl(-)-HCO-3 exchangers because of the lack of effect of bicarbonate removal or of the inhibitors amiloride and 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid. NaCl entry was reversibly inhibited by bumetanide in the mucosal bathing solution. Transepithelial NaCl and water absorption is the result of the coupled, carrier-mediated movement of NaCl into the cell across the apical membrane and the active extrusion of Na+ by the Na+-K+-ATPase in the basolateral membrane.

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