Hypertonicity inhibits a variety of neutrophil functions through poorly defined mechanisms. Our earlier studies suggest that osmotically induced actin polymerization and cytoskeleton remodeling is a key component in the hypertonic block of exocytosis and cell movement. To gain insight into the signaling mechanisms underlying the hyperosmotic F-actin response, we investigated whether hypertonici...

The different parts of the renal nephron have different functions that are related to reabsorption or secretion processes. This is mediated by genes that show a distinct expression pattern along the renal nephron segments (1). The majority of the segments contain only one epithelial cell type. However, the collecting duct is built up by principal cells (PCs), type A intercalated cells (A-ICs), ...

Insulin and hypertonicity each increase the content of GLUT4 glucose transporters at the surface of muscle cells. Insulin enhances GLUT4 exocytosis without diminishing its endocytosis. The insulin but not the hypertonicity response is reduced by tetanus neurotoxin, which cleaves vesicle-associated membrane protein (VAMP)2 and VAMP3, and is rescued upon introducing tetanus neurotoxin-resistant V...

The driving force for renal water reabsorption is provided by the osmolarity gradient between the interstitium and the tubular lumen, which is subject to rapid physiologic variations as a consequence of water intake fluctuations. The effect of increased extracellular tonicity/osmolarity on vasopressin-inducible aquaporin-2 (AQP2) expression in immortalized mouse collecting duct principal cells ...

Disturbances in tonicity (effective osmolarity) are the major clinical disorders affecting cell volume. Cell shrinking secondary to hypertonicity causes severe clinical manifestations and even death. Quantitative management of hypertonic disorders is based on formulas computing the volume of hypotonic fluids required to correct a given level of hypertonicity. These formulas have limitations. Th...

Mammalian renal inner medullary (IM) cells routinely face and resist hypertonic stress. Such stress causes DNA damage to which IM cells respond with cell cycle arrest. We report that three growth arrest and DNA damage-inducible 45 (GADD45) isoforms (GADD45alpha, GADDD45beta, and GADD45gamma) are induced by acute hypertonicity in murine IM cells. Maximum induction occurs 16-18 h after the onset ...

A previous study showed that with hypertonic sucrose treatment, a projection is formed in mouse metaphase II (MII) oocytes in proximity to the spindle and chromosomes, where a polarized cortical domain is located. However, little is known about the mechanisms involved in this process. Here, we designed a series of experiments to test the hypothesis that hypertonicity is the induction factor for...

Chernova, Marina N., Andrew K. Stewart, Lianwei Jiang, David J. Friedman, Yune Z. Kunes, and Seth L. Alper. Structure-function relationships of AE2 regulation by Cai 2 -sensitive stimulators NH4 and hypertonicity. Am J Physiol Cell Physiol 284: C1235–C1246, 2003. First published January 15, 2003; 10.1152/ajpcell.00522.2002.—We showed previously that the nonerythroid anion exchanger AE2 and the ...

In hypertonic environment, taurine accumulates in cells via activation of TauT (taurine transporter) as an adaptive regulation. Recent studies revealed that TonE (tonicity-responsive element)/TonEBP (TonE-binding protein) pathway regulated the expression of various molecules which protect cells against hypertonic stress. In the present study, we investigated the osmoregulatory mechanisms of Tau...