Regulation of tubular cell MCP-1 production by intracellular ions: a role for sodium and calcium.
Proximal tubule cells (PTC) in chronic renal disease produce chemokines which cause renal interstitial inflammation, and also transport more Na+ than normal. To investigate whether these two events might be related, monocyte chemoattractant protein-1 (MCP-1) production was examined in rat PTC in primary culture. Amiloride reduced, while ouabain increased levels of MCP-1 mRNA and protein. Amiloride reduced MCP-1 in cells stimulated with ouabain, lipopolysaccharide (LPS) or albumin. Intracellular Na+ rose with ouabain, but not LPS or albumin. Effects of amiloride, ouabain, LPS and albumin were abrogated by sodium-free but not chloride-free culture medium, and were not explained by changes in intracellular pH. Intracellular Ca2+ rose with ouabain, LPS or albumin and sodium-free medium. BAPTA-AM reduced intracellular Ca2+ and MCP-1 mRNA levels in unstimulated cells, and cells stimulated with ouabain, LPS or albumin. Thus, amiloride and ouabain may alter tubular cell MCP-1 by changing intracellular Na+, with secondary changes in intracellular Ca2+, whereas stimulation by LPS and albumin may involve Ca2+ directly.
Harris
D C
DC
Department of Renal Medicine, The University of Sydney at Westmead Hospital, Westmead, NSW, Australia. dch@medicine.usyd.edu.au
Wang
Y
Y
Campbell
D
D
D000136:Acid-Base Equilibrium / Q000502:physiology; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D004797:Enzyme-Linked Immunosorbent Assay; D005456:Fluorescent Dyes; D006863:Hydrogen-Ion Concentration; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D010042:Ouabain / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012964:Sodium / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013050:Spectrometry, Fluorescence
D018932:Chemokine CCL2; D005456:Fluorescent Dyes; D008070:Lipopolysaccharides; D012333:RNA, Messenger; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D004533:Egtazic Acid; D010042:Ouabain; D000584:Amiloride; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium; C039614:ethylisopropylamiloride