HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 564/3/715    most recent jphysiol.2004.081463v1 Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Neuhofer, W. Articles by Beck, F.-X. Search for Related Content PubMed PubMed Citation Articles by Neuhofer, W. Articles by Beck, F.-X.

¹ Department of Physiology, University of Munich, Germany

The adaptation of renal medullary cells to their hyperosmotic environment involves the accumulation of compatible organic osmolytes and the enhanced synthesis of heat shock proteins (HSP) 27 and 70. While the mechanisms leading to osmolyte accumulation are similar in papillary collecting duct (PCD) and papillary interstitial (PI) cells, the present data demonstrate that HSP27 and HSP70 are expressed differentially in these cells both in vivo and in vitro. HSP70 is abundant in PCD, but not expressed in PI cells in the papilla in situ, while HSP27 is expressed in both PCD and PI cells. These observations could be reproduced by non-permeant solutes in cultured cells. Osmotic stress strongly induced HSP70 in MDCK cells (as a model for PCD cells), but not in PI cells, while HSP27 was constitutively expressed in MDCK cells and was up-regulated in PI cells. Since prior hypertonic stress (NaCl addition) protects MDCK against subsequent exposure to high urea concentrations, this effect was also assessed in PI cells. In both cell lines, hypertonic pretreatment prior to urea exposure (400 mM) strongly attenuated caspase-3 activation. Inhibition of HSP27 expression by antisense transfection diminished the protective effect of hypertonic preconditioning in PI cells, while attenuation of HSP70 expression in MDCK cells diminished the protective effect of hypertonic preconditioning in these cells. These observations indicate that PCD and PI cells employ cell-specific mechanisms for protection against high urea concentrations as present in the renal papilla during antidiuresis.

(Received 16 December 2004; accepted after revision 10 February 2005; first published online 17 February 2005)
Corresponding author W. Neuhofer: Department of Physiology, University of Munich, Pettenkoferstrasse 12, 80336 Munich, Germany. Email: wolfgang.neuhofer{at}med.uni-muenchen.de

This article has been cited by other articles:

				A. R. A. Villalobos and J. L. Renfro Trimethylamine oxide suppresses stress-induced alteration of organic anion transport in choroid plexus J. Exp. Biol., February 1, 2007; 210(3): 541 - 552. [Abstract] [Full Text] [PDF]