title: Effect of protein kinase C inhibitors on interferon-beta production by viral and non-viral inducers.
abstract: Induction of interferon-beta (IFN-beta) in human (BG-9), simian (CV-1) and mouse (L-929) cell lines by Sendai virus and by poly(rI). poly(rC) has been studied for its possible dependence on protein kinase C (PKC) through the use of pharmacological inhibitors (K252a and H-7) of PKC. Exposure of BG-9, CV-1 or L-929 cells to K252a (greater than or equal to 0.025 microM), a staurosporine derivative, 24 h before or after induction of IFN with poly(rI).poly(rC), inhibited by greater than 95% the production of IFN-beta. In contrast, virus-induced IFN production was enhanced threefold or more by K252a in BG-9 and L-929 but not in CV-1 cells. A naphthalene sulphonamide inhibitor of PKC, H-7, at greater than or equal to 5 microM, decreased poly(rI).poly(rC)-induced IFN production in BG-9 and CV-1 cells by 75 to 94%, but had no effect on IFN production in L-929 cells. Viral induction of IFN was not affected significantly by H-7 in BG-9, CV-1 and L-929 cells. In contrast to these results, the calmodulin inhibitor, trifluoperazine (5 to 15 microM) did not affect IFN-beta production by poly(rI).poly(rC) but significantly enhanced IFN production by Sendai virus in both human and murine cell lines. Thus, in human and simian fibroblasts the induction of IFN-beta by poly(rI).poly(rC) appears to be PKC-dependent, whereas viral induction of IFN-beta is not. Results with K252a implicate PKC in non-viral induction of IFN in mouse fibroblasts, as well. Direct measurements of PKC activity in BG-9 cells exposed to several concentrations of K252a showed that the membrane PKC activity is significantly more sensitive to inhibition by K252a than is cytosolic PKC activity. In L-929 cells, K252a inhibited membrane PKC activity similarly, but was less effective as an inhibitor of cytosolic enzyme activity than in BG-9. These studies support an integral role for PKC activity, particularly membrane-associated activity, in non-viral [poly(rI).poly(rC)] induction of IFN-beta in human, simian and mouse fibroblasts.
authors.affiliation: Department of Microbiology, School of Medicine and Biomedical Sciences, State University of New York, Buffalo 14214.
authors.forename: H R
authors.initials: HR
authors.lastname: Thacore
authors.forename: H Y
authors.initials: HY
authors.lastname: Lin
authors.forename: P J
authors.initials: PJ
authors.lastname: Davis
authors.forename: M
authors.initials: M
authors.lastname: Schoenl
mesh_terms: D000818:Animals; D002227:Carbazoles / Q000494:pharmacology*; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D006801:Humans; D026121:Indole Alkaloids; D007369:Interferon Inducers / Q000494:pharmacology*; D007370:Interferon Type I / Q000096:biosynthesis*; D007700:Kinetics; D007739:L Cells / Q000187:drug effects / Q000201:enzymology / Q000276:immunology; D051379:Mice; D010222:Parainfluenza Virus 1, Human / Q000276:immunology; D011070:Poly I-C / Q000494:pharmacology*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D014268:Trifluoperazine / Q000494:pharmacology
chemical_list: D002227:Carbazoles; D026121:Indole Alkaloids; D007369:Interferon Inducers; D007370:Interferon Type I; D014268:Trifluoperazine; C049985:staurosporine aglycone; D011493:Protein Kinase C; D011070:Poly I-C