Na+/myo-inositol transport is regulated by basolateral tonicity in Madin-Darby canine kidney cells.

Yamauchi, Atsushi; Sugiura, Toshihiro; Ito, Taira; Miyai, Akiko; Horio, Masaru; Imai, Enyu; Kamada, Takenobu

doi:10.1172/jci118401

Cited by 30 publications

(13 citation statements)

References 25 publications

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“…NaCl loading was achieved by feeding sucrose solution (3 g/l) to prevent dehydration and standard rat chow for several days, followed by i.p. injection of NaCl (1.5 M; 1.5 ml/100 g body weight; 14). Where indicated, furosemide (3 mg/kg) was administered i.pl at the beginning of each procedure.…”

Section: Uninephrectomy and Nacl Loading Of Ratsmentioning

confidence: 99%

ORP150/HSP12A protects renal tubular epithelium from ischemia‐induced cell death

Bandô¹,

Tsukamoto

Katayama³

et al. 2004

FASEB j.

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The 150 kDa oxygen-regulated protein (ORP150) is an inducible endoplasmic reticulum (ER) chaperone with cytoprotective properties in settings of cell stress, such as ischemia/reperfusion (I/R). Renal tissue from patients with acute renal failure displayed strong induction of ORP150 in tubular epithelium. In a rodent model of renal I/R injury, ORP150 was expressed in both the ischemic and contralateral kidney, principally in the thick ascending loop of Henle (TAL) and distal tubules. Cultured renal epithelial cells exposed to hypoxic or hyperosmotic conditions displayed induction of ORP150. Renal tubular epithelial cells stably transfected with ORP150 sense or antisense cDNA displayed a strong correlation between ORP150 expression and vulnerability to hypoxic/osmotic stress; higher levels of ORP150 were protective, whereas lower levels increased susceptibility to cell death. Compared with nontransgenic controls, transgenic mice overexpressing ORP150 subjected to renal I/R displayed a blunted rise of serum creatinine and blood urea nitrogen, and enhanced survival of TAL, consistent with cytoprotection. In contrast, heterozygous ORP150+/- mice, with lower levels of ORP150, showed enhanced renal injury. These data are consistent with the possibility that ORP150 exerts cytoprotective effects in renal tubular epithelia subjected to I/R injury and suggest a key role for ER stress in the renal tubular response to acute renal failure.

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Section: Uninephrectomy and Nacl Loading Of Ratsmentioning

confidence: 99%

ORP150/HSP12A protects renal tubular epithelium from ischemia‐induced cell death

Bandô¹,

Tsukamoto

Katayama³

et al. 2004

FASEB j.

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“…The myo-inositol taken up by the Na + -dependent myo-inositol cotransporter originates from both dietary intake and synthesis from D-glucose via glucose 6-phosphate and myo-inositol 1-phosphate [8,37]. Since in cultured renal epithelial cells the Na + /myo-inositol cotransporter is localized preferentially in the basolateral plasma membrane [144,146], it is reasonable to assume that, in the medulla, inositol must be delivered via the vascular route to be taken up by the tubule cells. The cDNA encoding the Na + myo-inositol transporter (SMIT) has been sequenced for several species [15,70,110,139,152].…”

Section: Myo-inositolmentioning

confidence: 99%

Cellular response to osmotic stress in the renal medulla

Beck¹,

Burger‐Kentischer²,

Müller³

1998

Pfl�gers Archiv European Journal of Physiology

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Cells of the renal medulla, which are exposed under normal physiological conditions to widely fluctuating extracellular solute concentrations, respond to hypertonic stress by accumulating the organic osmolytes glycerophosphorylcholine (GPC), betaine, myo-inositol, sorbitol and free amino acids. Increased intracellular contents of these osmolytes are achieved by a combination of increased uptake (myo-inositol and betaine) and synthesis (sorbitol, possibly GPC), decreased degradation (GPC) and reduced osmolyte release. In the medulla of the concentrating kidney, accumulation of organic osmolytes, which do not perturb cell function even at high concentrations, allows the maintenance of "normal" intracellular concentrations of inorganic electrolytes. Adaptation to decreasing extracellular solute concentrations, e.g. diuresis, is achieved primarily by activation of pathways allowing the efflux of organic osmolytes, and secondarily by inactivation of production (sorbitol) and uptake (betaine, myo-inositol) and stimulation of degradation (GPC). Apart from modulation of the osmolyte content, osmolality-dependent reorganization of the cytoskeleton and expression of specific stress proteins (heat shock proteins) may be further, as yet poorly characterized, components of the regulatory systems involved in the adaptation of medullary cells to osmotic stress.

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“…As compared to RVI accomplished by ions, accumulation of osmolytes is a slow process often taking hours to days. Osmolyte accumulation is mediated by the transcriptional activation of genes encoding for proteins such as aldose reductase which catalyzes the hydration of glucose to sorbitol, and the Na + -or Na + Cl --coupled cotransporter or betaine, inositol, amino acids and taurine that are directly involved in the metabolism and transport of osmolytes [8][9][10][11][12][13]. The signaling mechanisms which direct the primary extracellular hyperosmolar stimulus to the tran-scription machinery of the nucleus are not yet completely understood.…”

Section: Osmotic Cell Shrinkage and Adaptive Gene Transcriptionmentioning

confidence: 99%