Effects of pathophysiological concentrations of albumin on NHE3 activity and cell proliferation in primary cultures of human proximal tubule cells

Lee, E, Pollock, C, Drumm, K, Barden, J and Poronnik, P 2003, 'Effects of pathophysiological concentrations of albumin on NHE3 activity and cell proliferation in primary cultures of human proximal tubule cells', American Journal of Physiology: Renal Physiology, vol. 285, no. 4, pp. 748-757.


Document type: Journal Article
Collection: Journal Articles

Title Effects of pathophysiological concentrations of albumin on NHE3 activity and cell proliferation in primary cultures of human proximal tubule cells
Author(s) Lee, E
Pollock, C
Drumm, K
Barden, J
Poronnik, P
Year 2003
Journal name American Journal of Physiology: Renal Physiology
Volume number 285
Issue number 4
Start page 748
End page 757
Total pages 10
Publisher American Physiological Society
Abstract The progression of renal disease correlates strongly with hypertension and the degree of proteinuria, suggesting a link between excessive Na+ reabsorption and exposure of the proximal tubule to protein. The present study investigated the effects of albumin on cell growth and Na+ uptake in primary cultures of human proximal tubule cells (PTC). Albumin (1.0 mg/ml) increased cell proliferation to 134.1 ± 11.8% (P < 0.001) of control levels with no change in levels of apoptosis. Exposure to 0.1 and 1.0 mg/ml albumin increased total 22Na+ uptake to 119.1 ± 6.3% (P = 0.005) and 115.6 ± 5.3% (P < 0.006) of control levels, respectively, because of an increase in Na+/H+ exchanger isoform 3 (NHE3) activity. This was associated with an increase in NHE3 mRNA to 161.1 ± 15.1% (P < 0.005) of control levels in response to 0.1 mg/ml albumin. Using confocal microscopy with a novel antibody raised against the predicted extracellular NH2 terminus of human NHE3, we observed in nonpermeabilized cells that exposure of PTC to albumin (0.1 and 1.0 mg/ml) increased NHE3 at the cell surface to 115.4 ± 2.7% (P < 0.0005) and 122.4 ± 3.7% (P < 0.0001) of control levels, respectively. This effect was paralleled by significant increases in NHE3 in the subplasmalemmal region as measured in permeabilized cells. These albumin-induced increases in expression and activity of NHE3 in PTC suggest a possible mechanism for Na + retention in response to proteinuria.
Subject Cell Physiology
Keyword(s) apoptosis
article
cell culture
cell growth
cell membrane
cell permeabilization
cell proliferation
concentration response
confocal microscopy
controlled study
disease severity
human
human cell
hypertension
kidney disease
kidney proximal tubule
kidney tubule cell
nucleotide sequence
pathophysiology
priority journal
protein expression
protein function
proteinuria
sodium absorption
sodium retention
ISSN 1931-857X
Versions
Version Filter Type
Citation counts: Scopus Citation Count Cited 29 times in Scopus Article | Citations
Access Statistics: 154 Abstract Views  -  Detailed Statistics
Created: Mon, 06 Dec 2010, 14:11:00 EST by Catalyst Administrator
© 2014 RMIT Research Repository • Powered by Fez SoftwareContact us