Accumulation of natural and synthetic betaines by a mammalian renal cell line

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.

1989 ◽  
Vol 257 (4) ◽  
pp. C795-C801 ◽  
Author(s):  
T. Nakanishi ◽  
M. B. Burg

Renal medullary cells contain high concentrations of "compatible" organic osmolytes such as glycerophosphorylcholine (GPC), betaine, myo-inositol, and sorbitol. The organic osmolytes occur as an osmoregulatory response to the high and variable interstitial NaCl concentration that is part of the urinary concentrating mechanism. Madin-Darby canine kidney (MDCK) cells in culture were previously shown to accumulate GPC in response to increased osmolality. We demonstrate here that this accumulation occurs in response to elevated extracellular urea concentration as well as to elevated NaCl. GPC does not accumulate unless either choline or GPC is present in the medium. Thus the accumulation results from osmoregulated synthesis of GPC from choline and, possibly, also osmoregulated uptake of extracellular GPC. When the osmolality is decreased from high to normal levels, cell GPC concentration decreases greatly over 24 h, accompanied by efflux of GPC and choline into the medium.


1989 ◽  
Vol 257 (5) ◽  
pp. C964-C970 ◽  
Author(s):  
T. Nakanishi ◽  
M. B. Burg

Renal medullary cells contain high concentrations of "compatible" organic osmolytes, such as myo-inositol, betaine, sorbitol, and glycero-phosphorylcholine. These organic osmolytes accumulate as an osmoregulatory response to the high and variable interstitial NaCl concentration that is part of the urinary concentrating mechanism. Madin-Darby canine kidney (MDCK) cells in culture were previously shown to accumulate myo-inositol and betaine in response to increased NaCl. These organic osmolytes are taken up by sodium-dependent active transport into the cells from the medium. The maximum concentration is not reached until 2-4 days after an increase in medium osmolality. The purpose of this study was to characterize the response to a decrease in medium osmolality of cells that had been grown at a high osmolality. The initial response to decreased osmolality was a rapid, transient efflux of both myo-inositol and betaine from the cells. Efflux was greatest during the first 15 min and resulted in a reduction of cell myo-inositol and betaine by almost 13 and 22%, respectively, after 3 h. Active myo-inositol and betaine influx fell more slowly, reaching a lower limit after approximately 1-2 days. The reduced influx was followed by progressive decrease in cell myo-inositol and betaine to approximately 30% of the initial value after 6 days. Thus, after a decrease in medium osmolality, MDCK cell myo-inositol and betaine fell because of a rapid, transient increase in efflux and a slow, sustained decrease in active influx.


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

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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