Regulation of immune complexes binding of macrophages by pectic polysaccharide from Bupleurum falcatum L.: pharmacological evidence for the requirement of intracellular calcium/calmodulin on Fc receptor up-regulation by bupleuran 2IIb.
The pectic polysaccharide, bupleuran 2IIb, up-regulates Fc-receptor (FcR) expression on peritoneal macrophages in a dose-dependent manner. The intracellular signal transduction by bupleuran 2IIb leading to the expression of FcR was studied. Neither the protein kinase C (PKC) inhibitor, 1-(5-isoquinolinylsulphonyl)-2-methylpiperazine dihydrochloride, nor the structurally distinct PKC antagonist, calphostin C, inhibited bupleuran 2IIb-induced up-regulation of FcR, whereas two direct activators of PKC, L-alpha-1-oleoyl-2-acetyl-sn-3-glycerol and N-(6-phenylhexyl)-5-chloro-1-naphthalenesulphonamide were unable to up-regulate the expression of FcR. The protein kinase A (PKA) inhibitor, N-[2-(methylamino)ethyl]-5-isoquinolinesulphonamide dihydrochloride also did not inhibit bupleuran 2IIb-induced up-regulation of FcR. Fluorescence image analysis using the calcium-sensitive dye, Fura-2, demonstrated that bupleuran 2IIb induced a rapid increase in intracellular levels of calcium (Ca2+). When macrophages were treated with calcium antagonist, 8-(diethylamino)-octyl-3,4,5-trimethoxybenzoate hydrochloride, bupleuran 2IIb-induced up-regulation of FcR was inhibited in a dose-dependent manner. The bupleuran 2IIb-induced up-regulation of FcR was also blocked by two structurally distinct calmodulin antagonists, trifluoperazine and N-(6-aminohexyl)-5-chloro-1-naphthalenesulphonamide hydrochloride. Furthermore, elevation of intracellular Ca2+ using the calcium ionophore, A23187, led to up-regulation of the FcR expression in a dose-dependent manner. These results suggest that bupleuran 2IIb induces the up-regulation of FcR on macrophages by a mechanism dependent on an increase in intracellular Ca2+ followed by activation of the calmodulin, but not by a PKC or PKA pathway.
Matsumoto
T
T
Oriental Medicine Research Center, Kitasato Institute, Tokyo, Japan.
Yamada
H
H
D000818:Animals; D000897:Anti-Ulcer Agents / Q000494:pharmacology; D000936:Antigen-Antibody Complex / Q000378:metabolism*; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000502:physiology; D002478:Cells, Cultured; D004075:Diglycerides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics; D007546:Isoquinolines / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051379:Mice; D010368:Pectins / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011961:Receptors, Fc / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics; D014268:Trifluoperazine / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
D000897:Anti-Ulcer Agents; D000936:Antigen-Antibody Complex; D002121:Calcium Channel Blockers; D002147:Calmodulin; D004075:Diglycerides; D007546:Isoquinolines; D011961:Receptors, Fc; D013449:Sulfonamides; C073829:Bupleuran 2IIc; D014268:Trifluoperazine; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; C017967:W 7; C034700:N-(6-aminohexyl)-1-naphthalenesulfonamide; C044388:N-(2-aminoethyl)-5-isoquinolinesulfonamide; C038237:1-oleoyl-2-acetylglycerol; D010368:Pectins; D011493:Protein Kinase C; D002118:Calcium