Effect of three lipophilic methotrexate derivatives upon mediator release by lipopolysaccharide-stimulated rat peritoneal macrophages.
The ability of methotrexate and three lipophilic derivatives (methotrexate-gamma-dimyristoylphosphatidylethanolamine (M gamma D), methotrexate-alpha-dimyristoylphosphatidylethanolamine (M alpha D) and methotrexate-alpha-gamma-di-dimyristoylphosphatidylethanolamine (M alpha gamma D) to modulate mediator release by lipopolysaccharide-stimulated rat peritoneal macrophages was investigated. At nontoxic concentrations, approximately 10 nmol/10(5) cells, M alpha D and M gamma D produced 11.06 +/- 1.0 and 75.6 +/- 5.2%, respectively, inhibition of tumour necrosis factor (TNF) release (mean +/- s.e.m., n = 4). At this same dose M alpha gamma D resulted in 68.8 +/- 2.1% inhibition of TNF but cellular ATP levels were reduced by 80%. The inhibitory activity of all three derivatives was dose-dependent. Non-derivatized methotrexate at a concentration of 25 nmol/10(5) cells had no inhibitory effect upon TNF release (14.7 +/- 0.8%, n = 3). Determination of prostaglandin E2 (PGE2) levels in the same samples demonstrated that all three conjugates were powerful inhibitors of prostaglandin release. At a quarter of the conjugate concentrations described above the monoamides M alpha (3.1 nmol/10(5) cells) and M gamma D (2.5 nmol/10(5) cells) maintained their effects on PGE2 production with 73 +/- 2.3 and 71 +/- 2.0% (n = 4) inhibition, respectively. At this lower concentration, however, the diamide M alpha gamma D (3.1 nmol/10(5) cells) was less effective in reducing the amount of PGE2 released from the macrophages (29 +/- 18%, n = 4). Maximal PGE2 inhibition by each of the conjugates was attained at approximately 5 nmol/10(5) cells. Unconjugated methotrexate (range of 2.5-20 nmol/10(5) cells) did not inhibit the release of PGE2 from lipopolysaccharide-stimulated macrophages.
Williams
A S
AS
Rheumatology Research Laboratory, University of Wales College of Medicine, Heath Park, Cardiff, UK.
Topley
N
N
Amos
N
N
Williams
B D
BD
D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D015232:Dinoprostone / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008727:Methotrexate / Q000031:analogs & derivatives / Q000633:toxicity*; D051379:Mice; D011863:Radioimmunoassay; D051381:Rats; D017208:Rats, Wistar; D014407:Tumor Cells, Cultured; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D015232:Dinoprostone; D008727:Methotrexate