MDP(Lysyl)GDP, a nontoxic muramyl dipeptide derivative, inhibits cytokine production by activated macrophages and protects mice from phorbol ester- and oxazolone-induced inflammation.
High levels of pro-inflammatory cytokines and nitric oxide are proposed to orchestrate pathophysiologic mechanism(s) associated with various inflammatory dermatoses. This study examines whether a water soluble 3-O-[N-acetylmuramyl-L-lysyl-D-iso]-2-di-on-glycine [MDP(Lysyl)GDP], a nontoxic and nonpyrogenic derivative of muramyl dipeptide (MDP), can inhibit the in vitro production of inflammatory mediators by lipopolysaccharide- or interferon-gamma-activated macrophages, and whether such an inhibitory effect can translate into in vivo protection of mice from irritant and allergic contact dermatitis. Thioglycollate-elicited peritoneal macrophages cultured in medium alone or in medium supplemented with MDP(Lysyl)GDP (1-100 microg per ml) expressed neither mRNA transcripts for inducible nitric oxide synthase, interleukin-1beta, and tumor necrosis factor-alpha, nor cytokine proteins and nitric oxide activity. Incubation of the cells with either lipopolysaccharide or interferon-gamma for 6 h resulted in a significant induction of inducible nitric oxide synthase, interleukin-1beta, and tumor necrosis factor-alpha mRNA, and the accumulation of high levels of monokines and nitrites in cultures by 24 h. Co-incubation of the macrophages with lipopolysaccharide or interferon-gamma and MDP(Lysyl)GDP (1-100 microg per ml) resulted in a concentration-dependent suppression of the steady-state mRNA transcripts for inducible nitric oxide synthase, tumor necrosis factor-alpha, and interleukin-1beta, induced by lipopolysaccharide, but not by interferon-gamma. In mouse models of phorbol ester- and oxazolone-induced ear inflammation, topical application of MDP(Lysyl)GDP significantly suppressed ear swelling in a dose-dependent manner. Likewise, oral treatment with MDP(Lysyl)GDP at days -3, -2, and -1 before elicitation with oxazolone also significantly inhibited ear inflammation. Taken together, our findings suggest that MDP(Lysyl)GDP has the potential to be a therapeutic application in the treatment of inflammatory conditions in which overproduction of pro-inflammatory mediators are implicated to play a pathogenic role.
Zunic
M
M
Novartis Forschungsinstitut, Vienna, Austria.
Bahr
G M
GM
Mudde
G C
GC
Meingassner
J G
JG
Lam
C
C
D000119:Acetylmuramyl-Alanyl-Isoglutamine / Q000494:pharmacology*; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis* / Q000235:genetics; D004151:Dipeptides / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation; D008264:Macrophages / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010081:Oxazolone / Q000633:toxicity*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D000893:Anti-Inflammatory Agents; D016207:Cytokines; D004151:Dipeptides; D008070:Lipopolysaccharides; C113177:MDP(lysyl)GDP; D010081:Oxazolone; D000119:Acetylmuramyl-Alanyl-Isoglutamine; D007371:Interferon-gamma; D013755:Tetradecanoylphorbol Acetate