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Influence of heat shock on cell volume regulation: protection from hypertonic challenge in a human monocyte cell line
Author(s) -
Oehler Rudolf,
Zellner Maria,
Hefel Beate,
Weingartmann Gertrude,
Spittler Andreas,
Struse Heidi M.,
Roth Erich
Publication year - 1998
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.12.7.553
Subject(s) - microbiology and biotechnology , shock (circulatory) , tonicity , chemistry , heat shock , u937 cell , cell culture , heat shock protein , intracellular , biophysics , biology , in vitro , biochemistry , medicine , genetics , gene
Heat shock response provides cells with higher tolerance against a variety of insults such as heavy metals, reperfusion injury, and endotoxin. In addition, heat treatment is known to affect ion transport mechanisms associated with vital cellular processes, including cell volume regulation. However, there has been no reports to date of a heat shock effect on cellular volume regulation itself. The aim of our study was to investigate whether the heat shock response influences volume regulation of cells. Human promonocytic U937 cells display an increase in volume in response to osmotic shrinkage. This regulatory volume increase (RVI) is mediated mainly by ion antiporters. U937 cells exposed to a temperature of 45°C for 10 min (heat shock) show an enhancement of RVI after hypertonic challenge compared with untreated cells. Also, heat‐treated cells display a lower intracellular pH (pH i ) than untreated cells; similar control mechanisms are believed to be involved in regulating both pH i and RVI. In agreement with this, heat‐shocked cells demonstrated increased activity of an HCO 3 − ‐independent/DIDS‐sensitive pH i down‐regulator, postulated to be a Cl − /HCO 3 − exchange. We suggest that heat shock‐mediated RVI enhancement is at least partially mediated by an increased Cl − /HCO 3 − exchange. Our results indicate that heat shock of U937 cells activates a hitherto unknown cytoprotective effect that may help cells to overcome hypertonic challenge.