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Published on: September 1, 2015
Cell-matrix interactions modulate transepithelial phosphate transport in P(i)-deprived OK cells
Mario Barac-Nieto1, Edward J Weinman, Adrian Spitzer
1Department of Physiology, Kuwait University, Safat, Kuwait. mario@hsc.edu.kw
American Journal of Physiology. Cell Physiology
|July 27, 2007
Summary
Phosphate (P(i)) depletion enhances sodium-dependent P(i) uptake in kidney cells. Matrigel coating improves P(i) transport by increasing apical NaPi4 transporter expression, boosting net P(i) transport.
Area of Science:
- Nephrology
- Cell Biology
- Biochemistry
Background:
- Phosphate (P(i)) transport is crucial for kidney function.
- In opossum kidney (OK) cells and proximal tubules, P(i) depletion increases Na(+)-dependent P(i) influx.
- OK cell monolayers, unlike proximal tubules, show no increased transepithelial P(i) transport, possibly due to cell-matrix interactions.
Purpose of the Study:
- To investigate the role of cell-matrix interactions in regulating P(i) transport in OK cells.
- To determine if Matrigel coating enhances P(i) transport by altering NaPi4 transporter expression and localization.
Main Methods:
- OK cells were grown on uncoated or Matrigel-coated filters and exposed to low or high P(i) conditions.
- Apical and basolateral (32)P(i) uptakes were measured.
- Transepithelial (32)P(i) and [(14)C]mannitol fluxes were assessed.
- Immunofluorescence was used to detect NaPi4 transporter expression.
Main Results:
- Matrigel coating increased apical NaPi4 transporter expression in P(i)-depleted cells.
- P(i) uptake was significantly higher in P(i)-depleted cells grown on Matrigel compared to those on uncoated filters.
- Matrigel enhanced net transepithelial P(i) transport from apical to basolateral sides, whereas paracellular mannitol flux was unaffected.
Conclusions:
- Matrigel-OK cell interactions enhance apical NaPi4 transporter expression, leading to increased P(i) transport rates.
- Matrigel facilitates P(i) entry into the transcellular transport pathway and increases net transepithelial P(i) transport.
- Cell-matrix interactions are critical for regulating kidney P(i) homeostasis.
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