Gentamicin suppresses endotoxin-driven TNF-alpha production in human and mouse proximal tubule cells.
Gentamicin is a mainstay in treating gram-negative sepsis. However, it also may potentiate endotoxin (LPS)-driven plasma TNF-alpha increases. Because gentamicin accumulates in renal tubules, this study addressed whether gentamicin directly alters LPS-driven tubular cell TNF-alpha production. HK-2 proximal tubular cells were incubated for 18 h with gentamicin (10-2,000 microg/ml). Subsequent LPS-mediated TNF-alpha increases (at 3 or 24 h; protein/mRNA) were determined. Gentamicin effects on overall protein synthesis ([(35)S]methionine incorporation), monocyte chemoattractant protein-1 (MCP-1) levels, and LPS-stimulated TNF-alpha generation by isolated mouse proximal tubules also were assessed. Finally, because gentamicin undergoes partial biliary excretion, its potential influence on gut TNF-alpha/MCP-1 mRNAs was probed. Gentamicin caused striking, dose-dependent inhibition of LPS-driven TNF-alpha production (up to 80% in HK-2 cells/isolated tubules). Surprisingly, this occurred despite increased TNF-alpha mRNA accumulation. Comparable changes in MCP-1 were observed. These changes were observed at clinically relevant gentamicin concentrations and despite essentially normal overall protein synthetic rates. Streptomycin also suppressed LPS-driven TNF-alpha increases, suggesting an aminoglycoside drug class effect. Gentamicin doubled basal TNF-alpha mRNA in cecum and in small intestine after LPS. Gentamicin can suppress LPS-driven TNF-alpha production in proximal tubule cells, likely by inhibiting its translation. Overall preservation of protein synthesis and comparable MCP-1 suppression suggest a semiselective blockade within the LPS inflammatory mediator cascade. These results, coupled with increases in gut TNF-alpha/MCP-1 mRNAs, imply that gentamicin may exert protean, countervailing actions on systemic cytokine/chemokine production during gram-negative sepsis.
Zager
Richard A
RA
Department of Medicine, University of Washington, Seattle, Washington, USA.
Johnson
Ali C M
AC
Geballe
Adam
A
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002460:Cell Line; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004731:Endotoxins / Q000494:pharmacology*; D005839:Gentamicins / Q000494:pharmacology*; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D012333:RNA, Messenger / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D000900:Anti-Bacterial Agents; C111835:CCL2 protein, human; C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D004731:Endotoxins; D005839:Gentamicins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha