Intracellular sorbitol content in isolated rat inner medullary collecting duct cells

Grunewald, R. Willi; Kinne, Rolf

doi:10.1007/bf00580961

Cited by 51 publications

(34 citation statements)

References 16 publications

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“…However, the extent in the increase in protein expression (more than 15-fold) was surprising when compared with the increase in mRNA expression in inner medulla cells (more than 4-fold) reported previously (11). High extracellular osmolarity induces renal sorbitol synthesis and accumulation in inner medullary collecting duct cells by increasing the AR activity and decreasing membrane permeability (25,26). The expression of the AR gene in the mammalian renal medulla has been shown to be osmotically regulated.…”

Section: Impact Of Osmotic Stress On Metabolic Proteinmentioning

confidence: 72%

Proteomic Analysis of Cellular Response to Osmotic Stress in Thick Ascending Limb of Henle’s Loop (TALH) Cells

Dihazi

Asif

Agarwal

et al. 2005

Molecular & Cellular Proteomics

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Epithelial cells of the thick ascending limb of Henle's loop (TALH cells) play a major role in the urinary concentrating mechanism. They are normally exposed to variable and often very high osmotic stress, which is particularly due to high sodium and chloride reabsorption and very low water permeability of the luminal membrane. It is already established that elevation of the activity of aldose reductase and hence an increase in intracellular sorbitol are indispensable for the osmotic adaptation and stability of the TALH cells. To identify new molecular factors potentially associated with the osmotic stress-resistant phenotype in kidney cells, TALH cells exhibiting low or high levels of resistance to osmotic stress were characterized using proteomic tools. Two-dimensional gel analysis showed a total number of 40 proteins that were differentially expressed in TALH cells under osmotic stress. Twenty-five proteins were overexpressed, whereas 15 proteins showed a down-regulation. Besides the sorbitol pathway enzyme aldose reductase, whose expression was 15 times increased, many other metabolic enzymes like glutathione S-transferase, malate dehydrogenase, lactate dehydrogenase, ␣ enolase, glyceraldehyde-3-phosphate dehydrogenase, and triose-phosphate isomerase were up-regulated. Among the cytoskeleton proteins and cytoskeleton-associated proteins vimentin, cytokeratin, tropomyosin 4, and annexins I, II, and V were up-regulated, whereas tubulin and tropomyosins 1, 2, and 3 were downregulated. The heat shock proteins ␣-crystallin chain B, HSP70, and HSP90 were found to be overexpressed. In contrast to the results in oxidative stress the endoplasmic reticulum stress proteins like glucose-regulated proteins (GRP78, GRP94, and GRP96), calreticulin, and proteindisulfide isomerase were down-regulated under hypertonic stress.

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Section: Impact Of Osmotic Stress On Metabolic Proteinmentioning

confidence: 72%

Proteomic Analysis of Cellular Response to Osmotic Stress in Thick Ascending Limb of Henle’s Loop (TALH) Cells

Dihazi

Asif

Agarwal

et al. 2005

Molecular & Cellular Proteomics

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“…It is conceivable that ERK itself or another ERK-responsive or ERKinducible kinase confers upregulation of one or more efflux pathways through posttranslational regulation (e.g., phosphorylation) of latent transport activity or through upregulation of transcription and translation of transport proteins. The former mechanism is favored in the case of inorganic ions and the osmolytes sorbitol (4,14,18,22,49,63) and inositol (36,38,64), where extremely rapid efflux has been documented. Although ERK activation does not appear to play a major role in cell survival after acute hypotonic stress (Fig.…”

Section: Discussionmentioning

confidence: 99%

Hypotonicity activates transcription through ERK-dependent and -independent pathways in renal cells

Zhang

Yang

Cohen

1998

American Journal of Physiology-Cell Physiology

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Hypotonicity activates transcription through ERK-dependent and -independent pathways in renal cells. Am. J. Physiol. 275 (Cell Physiol. 44): C1104-C1112, 1998.-Acute hypotonic shock (50% dilution of medium with sterile water, but not with isotonic NaCl) activated the extracellular signal response kinase (ERK) mitogen-activated protein (MAP) kinases in renal medullary cells, as measured by Western analysis with a phospho-ERK-specific antibody and by in vitro kinase assay of epitope-tagged ERKs immunoprecipitated from stable HA-ERK transfectants. Hypotonicity also activated the transcription factor and ERK substrate Elk-1 in a partially PD-98059-sensitive fashion, as assessed by chimeric reporter gene assay. Consistent with these data, hypotonic stress activated transcription of the immediate-early gene transcription factor Egr-1 in a partially PD-98059-sensitive fashion. Hypotonicity-inducible Egr-1 transcription was mediated in part through 5Ј-flanking regions containing serum response elements and in part through the minimal Egr-1 promoter. Elimination of the Ets motifs adjacent to key regulatory serum response elements in the Egr-1 promoter diminished the effect of hypotonicity but failed to abolish it. Interestingly, hypotonicity also transiently activated p38 and c-Jun NH 2 -terminal kinase 1, as determined by immunoblotting with anti-phospho-MAP kinase antibodies. Taken together, these data strongly suggest that hypotonicity activates immediate-early gene transcription in renal medullary cells via MAP kinase kinase-dependent and -independent mechanisms. urea; kidney; signal transduction; p38; stress-activated protein kinase; c-Jun amino-terminal kinase ALTHOUGH UBIQUITOUS among prokaryotes and simple eukaryotes, exposure to hypotonicity in higher eukaryotes is generally limited to relatively few epithelia in the absence of systemic disturbances in water balance. In response to water loading or diuresis, cells of the renal medulla encounter a markedly hypotonic milieu (20). In addition, the total solute concentration of a markedly hypertonic renal medullary interstitium, achievable in the face of avid water conservation and comprising a total solute burden Ͼ2,000 mosM, may fall by Ͼ50% in Ͻ1 h after diuresis (5). In response to such physiological anisotonicity, cell volume is acutely regulated through rapid influx or efflux of inorganic ions (e.g., K ϩ and Cl Ϫ ). Thereafter, accumulation or dumping of osmotically active organic solutes called osmolytes ensues (20). In aggregate, these sequential mechanisms achieve the regulatory volume decrease (RVD) essential for maintenance of cell integrity in response to hypotonicity.The molecular mechanisms underlying RVD have received increasing attention; inorganic ion and organic solute efflux pathways have been characterized. Swelling-responsive inorganic ion currents have been observed in diverse systems from prokaryotes to mammalian cells (reviewed in Ref. 8). Among renal epithelia, Cl Ϫ and cation currents have been detected in cells of the proximal tubule (62)...

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“…Sorbitol was determined in the supernatant using a commercially available test kit (Boehringer, Mannheim, Germany). Sorbitol synthesis was calculated as described previously [4]. …”

Section: Methodsmentioning

confidence: 99%

“…High extracellular NaCl and glucose induces sorbitol accumulation in the cells of the inner renal medulla [1, 3, 4]. This increase of intracellular sorbitol content is accompanied and augmented by an induction of aldose reductase [5].…”

Section: Introductionmentioning

confidence: 99%

“…This increase of intracellular sorbitol content is accompanied and augmented by an induction of aldose reductase [5]. However, intracellular sorbitol concentration in papillary collecting duct cells in primary culture increases with extracellular osmolarity and seems to be regulated by changes in membrane sorbitol permeability [4]. A number of reduced nicotinamide adenin dinucleotide phosphate (NADPH)-dependent oxidoreductases, like aldose reductases and aldehyde reductases, are distributed in various mammalian tissues [6, 7].…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Aldose Reductase from the Thick Ascending Limb of Henle’s Loop of Rabbit Kidney

Grunewald

Eckstein²,

Reisse³

et al. 2001

Nephron

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Background: The organic osmolyte sorbitol plays an important role in the osmoregulation of immortalized epithelial cells of the thick ascending limb of Henle’s loop (TALH) of rabbit. The intracellular sorbitol content seems to depend strongly on the extracellular osmolarity. To investigate the nature of the osmotic regulation we characterized the aldose reductase. Methods: We determined aldose reductase activity enzymatically and the content of organic osmolytes by HPLC. Results: The aldose reductase activity correlates with the extracellular tonicity. Elevating the osmolarity of the medium from 300 to 600 mosm/l by addition of NaCl or sucrose resulted in a significant increase of maximal velocity (V_max) of the adapted cells from 8 ± 1 µmol/g × min (300 mosm/l) to 322 ± 28 µmol/g × min (600 mosm/l, NaCl) or 54 ± 9 µmol/g × min (600 mosm/l, sucrose), respectively, while affinity (K_m) remained unchanged. But we found no rise of aldose reductase activity when extracellular urea concentration was elevated. Similar alterations in V_max were observed when the activity of the highly enriched enzyme was determined with glucose as substrate. Elevation of the extracellular osmolarity by NaCl and sucrose strongly induced the expression of aldose reductase protein with an apparent molecular weight of 39 kD. The affinity of glucose is characteristically low with a K_m above 300 mmol/l. Aldose reductase utilizes both NADPH and with lower affinity NADH as coenzymes. In vitro sulfate ions (0.4 mol/l) results in a two-fold activation of the aldose reductase activity whereas sodium (200–400 mmol/l) decreased the activity significantly (22–33%). Potassium and chloride up to 400 mmol/l did not alter the aldose reductase activity in vitro. Conclusions: These results indicate that the aldose reductase of TALH cells of the outer medulla is osmotically regulated and has many similarities with aldose reductase in renal inner medulla. Therefore, intracellular sorbitol synthesis seems to be of similar importance in the osmoregulation of TALH cells as in the inner medulla.

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Intracellular sorbitol content in isolated rat inner medullary collecting duct cells

Cited by 51 publications

References 16 publications

Proteomic Analysis of Cellular Response to Osmotic Stress in Thick Ascending Limb of Henle’s Loop (TALH) Cells

Proteomic Analysis of Cellular Response to Osmotic Stress in Thick Ascending Limb of Henle’s Loop (TALH) Cells

Hypotonicity activates transcription through ERK-dependent and -independent pathways in renal cells

Characterization of Aldose Reductase from the Thick Ascending Limb of Henle’s Loop of Rabbit Kidney

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