Chronic hyperosmolarity mediates constitutive expression of molecular chaperones and resistance to injury

Bento C. Santos, James M. Pullman, Alejandro Chevaile, William J. Welch, Steven R. Gullans

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

Renal medullary cells are exposed to elevated and variable osmolarities and low oxygen tension. Despite the harsh environment, these cells are resistant to the effects of many harmful events. To test the hypothesis that this resistance is a consequence of these cells developing a stress tolerance phenotype to survive in this milieu, we created osmotically tolerant cells [hypertonic (HT) cells] by gradually adapting murine inner medullary collecting duct 3 cells to hyperosmotic medium containing NaCl and urea. HT cells have a reduced DNA synthesis rate, with the majority of cells arrested in the G0/G1 phase of the cell cycle, and show constitutive expression of heat shock protein 70 that is proportional to the degree of hyperosmolarity. Unlike acute hyperosmolarity, chronic hyperosmolarity failed to activate MAPKs. Moreover, HT cells acquired protein translational tolerance to further stress treatment, suggesting that HT cells have an osmotolerant phenotype that is analogous to thermotolerance but is a permanent condition. In addition to osmotic shock, HT cells were more resistant to heat, H2O2, cyclosporin, and apoptotic inducers, compared with isotonic murine inner medullary duct 3 cells, but less resistant to amphotericin B and cadmium. HT cells demonstrate that in renal medullary cells, hyperosmotic stress activates biological processes that confer cross-tolerance to other stressful conditions.

Original languageEnglish (US)
Pages (from-to)F564-F574
JournalAmerican Journal of Physiology - Renal Physiology
Volume284
Issue number3 53-3
StatePublished - Mar 1 2003
Externally publishedYes

Keywords

  • Cell cycle
  • Heat shock protein 70
  • Inner medullary collecting duct 3
  • Nephrotoxins
  • Thermotolerance

ASJC Scopus subject areas

  • Physiology
  • Urology

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