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Dynamic effects of Hg2+-induced changes in cell volume
Jinseok Heo1, Fanjie Meng, Frederick Sachs
1Department of Mechanical and Aerospace Engineering, SUNY-Buffalo, 340 Jarvis Hall, Buffalo, NY 14260, USA.
Cell Biochemistry and Biophysics
|March 28, 2008
Summary
Mercury (Hg2+) significantly alters cell volume regulation under hypotonic stress in CHO cells, leading to excessive swelling. This effect involves altered ion transport and potentially cytoskeletal changes.
Area of Science:
- Cell Biology
- Biophysics
- Toxicology
Background:
- Hypotonic stress induces cell swelling.
- Regulatory volume decrease (RVD) is a cellular mechanism to counteract swelling.
- Mercury ions (Hg2+) are known cellular toxins.
Purpose of the Study:
- To investigate the dynamic effects of Hg2+ on hypotonic stress-induced volume changes in Chinese Hamster Ovary (CHO) cells.
- To elucidate the mechanisms underlying Hg2+-induced alterations in cell volume regulation.
Main Methods:
- Utilized a microfluidic volume sensor to monitor real-time cell volume.
- Applied hypotonic challenges to CHO cells with and without Hg2+ exposure.
- Manipulated extracellular ion concentrations (Na+, K+, Cl-) and used channel blockers.
Main Results:
- Hg2+ treatment caused substantial and biphasic cell swelling under hypotonic conditions.
- Replacing extracellular Na+ with NMDG+ abolished Hg2+-induced swelling and promoted RVD-like decrease.
- Hg2+-induced volume changes were partially inhibited by K+ and Cl- channel blockers, suggesting altered ion fluxes.
- Cellular response was sensitive to stimulation history, indicating potential cytoskeletal involvement.
Conclusions:
- Hg2+ significantly impairs RVD and promotes excessive cell swelling during osmotic stress.
- Hg2+ appears to increase NaCl influx relative to KCl efflux.
- Cytoskeletal mechanical stress may also contribute to the observed Hg2+ effects on cell volume regulation.
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