Effect of Leishmania donovani lipophosphoglycan on ornithine decarboxylase activity in macrophages.
Lipophosphoglycan (LPG), a major surface molecule from Leishmania donovani, stimulated ornithine decarboxylase (ODC) activity in macrophages in a dose- and time-dependent manner. LPG stimulated the rapid increase in ODC activity within 30 min after exposure, suggesting that the interaction of LPG with its receptor stimulated a specific signal transduction pathway. However, LPG-induced ODC activity was a transient event because 3 hr after exposure to LPG, no stimulation of ODC activity was detectable. ODC activity appeared to be coupled to the activation of protein kinase C (PKC) in macrophages, as activators of PKC caused a rapid increase in the ODC activity. Macrophages pretreated with LPG for 1 hr became unresponsive to subsequent stimulation by the PKC activators 1-oleoyl-2-acetyl-glycerol and the calcium ionophore A23187. In contrast, the ability of macrophages to express ODC activity in response to the cyclic AMP analogue dibutyryl cyclic AMP was not impaired by LPG.
Kapoor
P
P
School of Life Sciences, Jawaharlal Nehru University, New Delhi, India.
Raj
V S
VS
Saxena
S
S
Balaraman
S
S
Madhubala
R
R
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000494:pharmacology; D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D004075:Diglycerides / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006028:Glycosphingolipids / Q000494:pharmacology* / Q000502:physiology; D007893:Leishmania donovani / Q000737:chemistry*; D007898:Leishmaniasis, Visceral / Q000469:parasitology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000201:enzymology*; D051379:Mice; D019319:Okadaic Acid / Q000494:pharmacology; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D019311:Staurosporine / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors
D000900:Anti-Bacterial Agents; D004075:Diglycerides; D004791:Enzyme Inhibitors; D006028:Glycosphingolipids; D008070:Lipopolysaccharides; C008290:lipophosphonoglycan; D019319:Okadaic Acid; D000001:Calcimycin; D003994:Bucladesine; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C038237:1-oleoyl-2-acetylglycerol; D009955:Ornithine Decarboxylase; D019311:Staurosporine; D013755:Tetradecanoylphorbol Acetate