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TRPV4 exhibits a functional role in cell-volume regulation
Daniel Becker1, Christopher Blase, Juergen Bereiter-Hahn
1Kinematic Cell Research Group, Johann Wolfgang Goethe University, Marie-Curie-Str. 9, 60439 Frankfurt, Germany.
Journal of Cell Science
|June 1, 2005
Summary
The transient receptor potential vanilloid 4 (TRPV4) channel directly participates in regulatory volume decrease (RVD) in human keratinocytes. TRPV4 activation allows calcium influx, crucial for cells to recover volume after hypotonic stress.
Area of Science:
- Cell Biology
- Physiology
- Molecular Biology
Background:
- Cell volume regulation is vital for homeostasis.
- Hypotonic stress causes cell swelling via osmosis.
- Regulatory Volume Decrease (RVD) actively reduces cell volume after swelling.
Purpose of the Study:
- To investigate the role of the TRPV4 channel in RVD.
- To determine if TRPV4 mediates calcium influx during RVD.
Main Methods:
- Used HaCaT cells (human keratinocytes) expressing endogenous TRPV4.
- Exposed cells to hypotonic conditions (200 mOsm) and measured volume changes and Ca2+ influx.
- Utilized TRPV4 inhibitor Gd3+ to assess its effect on RVD.
- Expressed recombinant TRPV4 in CHO cells, which lack endogenous TRPV4 and RVD.
Main Results:
- HaCaT cells exhibited RVD and increased Ca2+ influx under hypotonic stress.
- Gd3+ inhibited RVD and Ca2+ influx in HaCaT cells.
- CHO cells expressing TRPV4 gained the ability to perform RVD.
- TRPV4-mediated RVD in CHO cells was reduced by Gd3+ or Ca2+-free conditions.
Conclusions:
- TRPV4 directly participates in the RVD process.
- TRPV4-mediated calcium influx is essential for RVD in response to hypotonic swelling.