Interferon-gamma down-regulates membrane adenylate cyclase activity of a murine macrophage-like cell line (P388D1).
Effects of recombinant murine interferon-gamma (rIFN-gamma) on the membrane adenylate cyclase of a murine macrophage cell line (P388D1) were investigated in order to explore the nature of a signal transmitted by IFN-gamma receptor. Following the incubation of P388D1 cells with 40 U/ml of rIFN-gamma, the intracellular level of cAMP gradually increased about twofold over the control level within 60 min, and then began to gradually decline to about half the control level by 24 h incubation. The initial rise in cAMP level appeared to be due to the modest activation of adenylate cyclase and not due to the inhibition of cAMP-phosphodiesterase. Later decrease of intracellular cAMP may be due to quantitative down-regulation of the adenylate cyclase system. The basal enzymatic activity of the membrane prepared from P388D1 cells exposed to IFN-gamma for 24 h was found to be reduced to about 20% of that of the control membrane. However, the quality of the adenylate cyclase system appeared unchanged, because the relative degree of the response of the down-regulated membrane adenylate cyclase to prostaglandin PGE2, NaF, guanylimidodiphosphate (GppNHp), choleara toxin (CT), or forskolin was found to remain unchanged. This quantitative down-regulation of adenylate cyclase must be due to the action of rIFN-gamma, since the prior treatment of rIFN-gamma with either acid (pH 2) or monoclonal anti-IFN-gamma antibody inhibited the ability of IFN-gamma to induce the down-regulation. The rIFN-gamma-induced down-regulation is a reversible process, since the adenylate cyclase activity of the membrane was found to be restored when the rIFN-gamma-exposed cells were cultured for 72 h in the absence of rIFN-gamma. In addition, the 48 h-incubation of P388D1 cells with rIFN-beta or IFN-alpha was found not to significantly affect the membrane adenylate cyclase system.
Adachi
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I
Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City 66103.
Connolly
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N
Suzuki
T
T
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors; D000067956:Adenylyl Cyclase Inhibitors; D000818:Animals; D002460:Cell Line / Q000187:drug effects; D002462:Cell Membrane / Q000187:drug effects* / Q000201:enzymology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000096:biosynthesis*; D015232:Dinoprostone / Q000494:pharmacology; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007371:Interferon-gamma / Q000494:pharmacology*; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D011994:Recombinant Proteins / Q000494:pharmacology; D015398:Signal Transduction; D012969:Sodium Fluoride
D000067956:Adenylyl Cyclase Inhibitors; D011994:Recombinant Proteins; D005576:Colforsin; D006165:Guanylyl Imidodiphosphate; D007371:Interferon-gamma; D012969:Sodium Fluoride; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D015232:Dinoprostone