Volume-activated calcium uptake: its role in cell volume regulation of Madin-Darby canine kidney cells

1992 ◽  
Vol 262 (2) ◽  
pp. C339-C347 ◽  
Author(s):  
A. Rothstein ◽  
E. Mack

Immediately after osmotic swelling of Madin-Darby canine kidney (MDCK) cells, a transient (1-2 min) increase in Ca2+ influx and internal Ca2+ (Ca2+i) is observed. The normal Ca2+ influx appears to be mediated by the 3Na(+)-Ca2+ exchange system [Borle et al. Am. J. Physiol. 259 (Cell Physiol. 28): C19-C25, 1990], but the swelling-induced component is different in 1) Na+ dependence, 2) affinity for Ca2+, 3) inhibition by La3+, and 4) direction of net flux at low external Ca2+. Swelling appears to activate an uncoupled Ca2+ flow, perhaps through cation-nonspecific stretch-activated channels. The regulatory volume decrease (RVD) is dependent on the swelling-induced pulse of Ca2+ influx and associated rise in Ca2+i. Swelling also induces a biphasic change in membrane potential, a hyperpolarization followed by depolarization, reflecting sequential increases in K+ and Cl- permeabilities. The time dependence of the former corresponds closely with the transient peak in Ca2+i, but the latter does not. Ca2+i appears to have a direct activating effect on K+ channels but an indirect effect on Cl- channels, mediated via other Ca(2+)-triggered systems. The sequence of events following cell swelling appears to be transient increases in Ca2+ permeability, Ca2+ influx, Ca2+i, K+ permeability, followed by triggering of a mediating system that increases Cl- permeability. The net result is KCl, osmotic water loss, and volume adjustment.

1991 ◽  
Vol 260 (1) ◽  
pp. C113-C121 ◽  
Author(s):  
A. Rothstein ◽  
E. Mack

The mercurial, p-chloromercuribenzoylsulfonate (PCMBS), blocks volume recovery of dissociated, osmotically swollen, Madin-Darby canine kidney cells (MDCK) and, at higher concentrations, induces substantial swelling. In the absence of Na+ the rate of volume recovery is, in contrast, substantially increased. PCMBS does not inhibit the "normal" volume-regulating pathways, K+ and Cl- conductances. Rather, its blocking action is due to substantial activation of Na+ and K+ permeabilities, especially the former. Consequently, the normal reshrinking mechanism, loss of KCl, is counterbalanced by PCMBS-induced gains of NaCl. In isotonic cells, PCMBS, at higher concentrations, induces cell swelling, indicating that Cl- permeability is also increased, a conclusion confirmed by direct measurement of 36Cl- fluxes. HgCl2 produces similar effects except that it is more potent and more rapid in its action. Activation of conductive ion permeabilities to Na+, K+, and Cl- are associated with appropriate changes in membrane potential. A small bumetanide-sensitive swelling component (Na(+)-Cl- cotransport) is activated by HgCl2 but not by PCMBS. Another effect is elevation of cytoplasmic Ca2+, apparently by mobilization from internal stores. Some of the functional sites (Na+ and K+) appear to be located externally, rapidly accessible to both HgCl2 and PCMBS, whereas others (Cl- and Ca2+) appear to be internal, rapidly accessible to the permeant HgCl2 but slowly to relatively impermeant PCMBS. In conclusion, the disturbances of volume regulation are largely due to the increases in conductive ion fluxes.


2015 ◽  
Vol 20 (5) ◽  
pp. 486-493 ◽  
Author(s):  
P. Muthuraman ◽  
P. C. Nagajyothi ◽  
M. Chandrasekaran ◽  
G. Enkhtaivan ◽  
B. Venkitasamy ◽  
...  

1996 ◽  
Vol 74 (2) ◽  
pp. 283-287 ◽  
Author(s):  
K. Randall ◽  
M. Lever ◽  
B. A. Peddie ◽  
S. T. Chambers

Intracellular accumulation of different betaines was compared in osmotically stressed Madin Darby canine kidney (MDCK) cells to model the betaine accumulation specificity of the mammalian inner medulla and to show how this accumulation differed from that of bacteria. All betaines accumulated less than glycine betaine. Arsenobetaine (the arsenic analogue of glycine betaine) accumulated to 12% of the glycine betaine levels and the sulphur analogue dimethylthetin accumulated to >80%. Most substituted glycine betaine analogues accumulated to 2–5% of intracellular glycine betaine concentrations, however, serine betaine accumulated to <0.5% of glycine betaine levels. Inhibition studies to distinguish the betaine ports were performed by the addition of proline. Butyrobetaine and carnitine accumulation was not proline sensitive, whereas that of omer betaines was. As with glycine betaine, the accumulation of propionobetaine and dimethylthetin was proline sensitive and osmoregulated. Pyridinium betaine was accumulated by both proline-sensitive and -insensitive systems, with a small increase under osmotic stress. High concentrations (10 times that of glycine betaine) of the dietary betaines proline betaine and trigonelline inhibited total betaine accumulation. Because α-substituted betaines are accumulated by bacteria and not by MDCK cells, these betaines may be the basis for design of antimicrobial agents.Key words: MDCK cells, betaine accumulation, osmolytes, betaine analogues.


1990 ◽  
Vol 18 (4) ◽  
pp. 255-258 ◽  
Author(s):  
W. L. Strohmaier ◽  
K. -H. Bichler ◽  
P. Deetjen ◽  
S. Kleinknecht ◽  
M. Pedro ◽  
...  

1994 ◽  
Vol 5 (10) ◽  
pp. 1093-1103 ◽  
Author(s):  
A K Rajasekaran ◽  
J S Humphrey ◽  
M Wagner ◽  
G Miesenböck ◽  
A Le Bivic ◽  
...  

Sorting of newly synthesized plasma membrane proteins to the apical or basolateral surface domains of polarized cells is currently thought to take place within the trans-Golgi network (TGN). To explore the relationship between protein localization to the TGN and sorting to the plasma membrane in polarized epithelial cells, we have expressed constructs encoding the TGN marker, TGN38, in Madin-Darby canine kidney (MDCK) cells. We report that TGN38 is predominantly localized to the TGN of these cells and recycles via the basolateral membrane. Analyses of the distribution of Tac-TGN38 chimeric proteins in MDCK cells suggest that the cytoplasmic domain of TGN38 has information leading to both TGN localization and cycling through the basolateral surface. Mutations of the cytoplasmic domain that disrupt TGN localization also lead to nonpolarized delivery of the chimeric proteins to both surface domains. These results demonstrate an apparent equivalence of basolateral and TGN localization determinants and support an evolutionary relationship between TGN and plasma membrane sorting processes.


1987 ◽  
Vol 7 (4) ◽  
pp. 1326-1337
Author(s):  
S L Warren ◽  
W J Nelson

Madin-Darby canine kidney (MDCK) cells form polarized, multicellular epithelial structures in vitro. Low-level expression of pp60v-src in MDCK cells elicits plasticity in these multicellular structures. Plasticity was revealed by the displacement of cells from mechanically stressed regions of the epithelial monolayers; however, the two-dimensional relationship between the cells in the remainder of the monolayer was maintained. Electron microscopy of multicellular structures revealed abnormal separation of the lateral membranes of adjacent cells and selective uncoupling of the junctional complex; the zonula adherens was disrupted, but the zonula occludens and desmosomes were retained. Significantly, this result was not accompanied by transformation of the cells, as judged by the absence of anchorage-independent growth potential. These results demonstrate a nonmitogenic biological activity of pp60v-src which is experimentally dissociable from transformation. This morphoregulatory action on higher-order epithelial structures may reflect a function of related cellular tyrosine kinases.


1999 ◽  
Vol 145 (1) ◽  
pp. 141-151 ◽  
Author(s):  
Rosa Puertollano ◽  
Fernando Martín-Belmonte ◽  
Jaime Millán ◽  
María del Carmen de Marco ◽  
Juan P. Albar ◽  
...  

The MAL (MAL/VIP17) proteolipid is a nonglycosylated integral membrane protein expressed in a restricted pattern of cell types, including T lymphocytes, myelin-forming cells, and polarized epithelial cells. Transport of the influenza virus hemagglutinin (HA) to the apical surface of epithelial Madin-Darby canine kidney (MDCK) cells appears to be mediated by a pathway involving glycolipid- and cholesterol- enriched membranes (GEMs). In MDCK cells, MAL has been proposed previously as being an element of the protein machinery for the GEM-dependent apical transport pathway. Using an antisense oligonucleotide-based strategy and a newly generated monoclonal antibody to canine MAL, herein we have approached the effect of MAL depletion on HA transport in MDCK cells. We have found that MAL depletion diminishes the presence of HA in GEMs, reduces the rate of HA transport to the cell surface, inhibits the delivery of HA to the apical surface, and produces partial missorting of HA to the basolateral membrane. These effects were corrected by ectopic expression of MAL in MDCK cells whose endogenous MAL protein was depleted. Our results indicate that MAL is necessary for both normal apical transport and accurate sorting of HA.


1987 ◽  
Vol 105 (4) ◽  
pp. 1623-1635 ◽  
Author(s):  
G van Meer ◽  
E H Stelzer ◽  
R W Wijnaendts-van-Resandt ◽  
K Simons

To study the intracellular transport of newly synthesized sphingolipids in epithelial cells we have used a fluorescent ceramide analog, N-6[7-nitro-2,1,3-benzoxadiazol-4-yl] aminocaproyl sphingosine (C6-NBD-ceramide; Lipsky, N. G., and R. E. Pagano, 1983, Proc. Natl. Acad. Sci. USA, 80:2608-2612) as a probe. This ceramide was readily taken up by filter-grown Madin-Darby canine kidney (MDCK) cells from liposomes at 0 degrees C. After penetration into the cell, the fluorescent probe accumulated in the Golgi area at temperatures between 0 and 20 degrees C. Chemical analysis showed that C6-NBD-ceramide was being converted into C6-NBD-sphingomyelin and C6-NBD-glucosyl-ceramide. An analysis of the fluorescence pattern after 1 h at 20 degrees C by means of a confocal scanning laser fluorescence microscope revealed that the fluorescent marker most likely concentrated in the Golgi complex itself. Little fluorescence was observed at the plasma membrane. Raising the temperature to 37 degrees C for 1 h resulted in intense plasma membrane staining and a loss of fluorescence from the Golgi complex. Addition of BSA to the apical medium cleared the fluorescence from the apical but not from the basolateral plasma membrane domain. The basolateral fluorescence could be depleted only by adding BSA to the basal side of a monolayer of MDCK cells grown on polycarbonate filters. We conclude that the fluorescent sphingomyelin and glucosylceramide were delivered from the Golgi complex to the plasma membrane where they accumulated in the external leaflet of the membrane bilayer. The results also demonstrated that the fatty acyl labeled lipids were unable to pass the tight junctions in either direction. Quantitation of the amount of NBD-lipids delivered to the apical and the basolateral plasma membranes during incubation for 1 h at 37 degrees C showed that the C6-NBD-glucosylceramide was two- to fourfold enriched on the apical as compared to the basolateral side, while C6-NBD-sphingomyelin was about equally distributed. Since the surface area of the apical plasma membrane is much smaller than that of the basolateral membrane, both lipids achieved a higher concentration on the apical surface. Altogether, our results suggest that the NBD-lipids are sorted in MDCK cells in a way similar to their natural counterparts.


2001 ◽  
Vol 12 (12) ◽  
pp. 2565-2571 ◽  
Author(s):  
Wolfgang Neuhofer ◽  
Karin Lugmayr ◽  
Maria-Luisa Fraek ◽  
Franz-X Beck

ABSTRACT. Exposure of renal medullary cells to elevated extracellular NaCl concentrations is associated with increased heat shock protein 72 (HSP72) expression and improved resistance to subsequent exposure to a high urea concentration (600 mM). To establish a causal relationship between HSP72 expression and protection against high urea concentrations, HSP72 was inducibly overexpressed in Madin-Darby canine kidney (MDCK) cells, in the absence of hypertonic stress before urea exposure. For this purpose, the human stress-inducible HSP72 gene was cloned downstream from a dexamethasone (DEX)-inducible promoter in the eukaryotic expression vector pLKneo. This construct allowed robust induction of HSP72 by exposure of stably transfected MDCK cells (MDCK-LK72) to 0.1 μM DEX. Increased HSP72 abundance significantly improved survival rates after 24-h exposure of the cells to medium containing 600 mM urea (14 versus 43%). In mock-transfected or wild-type cells, DEX had no significant effect on HSP72 abundance or urea resistance. In accordance with those findings, lactate dehydrogenase activity in the supernatant was significantly reduced, compared with appropriate control samples, only in MDCK-LK72 cells overexpressing HSP72. Labeling with annexin V-FITC and propidium iodide, followed by flow cytometry, revealed that overexpression of HSP72 was associated with a reduction in the number of apoptotic-lysed cells, a concomitant retardation of apoptosis, and an increase in the number of viable cells. These data support the view that HSP72, which is very abundant in the renal inner medulla, is an important component of the defense mechanism of medullary cells against extreme concentrations of urea.


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