Related Experiment Videos
Hypertonicity increases CLC-5 expression in mouse medullary thick ascending limb cells
Phuong-Chi Pham1, Olivier Devuyst, Phuong-Thu Pham
1Renal Division, Department of Medicine, Olive View-UCLA Medical Center, Sylmar, CA 91342, USA. pctp@ucla.edu
American Journal of Physiology. Renal Physiology
|May 27, 2004
Summary
Hypertonicity upregulates chloride channel CLC-5 in the kidney's medullary thick ascending limb (mTAL) cells, unlike proximal tubule cells. This suggests CLC-5 maintains endocytosis in the hypertonic renal medulla.
Area of Science:
- Nephrology
- Molecular Biology
- Cell Physiology
Background:
- Mutations in chloride channel CLC-5 cause Dent's disease.
- CLC-5 is expressed in kidney proximal tubules, medullary thick ascending limb (mTAL), and collecting tubules.
- CLC-5 is vital for endocytosis in proximal tubules, but its role in mTAL is unknown.
Purpose of the Study:
- To investigate the effect of hypertonicity on CLC-5 expression in mTAL cells.
- To determine if hypertonicity influences CLC-5's role in endocytosis in different kidney segments.
Main Methods:
- Utilized a murine mTAL cell line (MTAL) and an opossum kidney (OK) proximal tubular cell line.
- Exposed cells and mouse kidneys to varying hypertonic conditions and water deprivation.
- Measured CLC-5 mRNA and protein levels via quantitative methods.
- Assessed cellular uptake of FITC-labeled albumin to evaluate endocytotic activity.
Main Results:
- Hypertonicity increased CLC-5 mRNA and protein in MTAL cells but not OK cells.
- Water deprivation in mice enhanced CLC-5 expression in the renal medulla, not the cortex.
- Hypertonicity decreased endocytosis in OK cells but not in MTAL cells.
Conclusions:
- CLC-5 expression is upregulated by hypertonicity specifically in mTAL cells.
- This upregulation may preserve endocytotic function within the hypertonic renal medulla.
- Findings highlight a segment-specific response of CLC-5 to renal medullary environment.