Essential Roles of PKA, iNOS, CD95/CD95L, and Terminal Caspases in Suppression of Eosinopoiesis by PGE2 and Other cAMP-Elevating Agents
Figure 5
Isoproterenol and receptor-independent cAMP inducers/mimetics suppress eosinophilopoiesis through an iNOS-dependent mechanism. Bone-marrow cultures were established from BALB/c ((a) and (b)) or iNOS-deficient (iNOS KO) and their wild-type control (C57BL/6) mice ((c) and (d)), in the presence of IL-5, alone or associated with 10−6 M isoproterenol (Iso) ((a) and (c)) or with the indicated concentrations of cholera toxin (Ch T) (b), forskolin (Fosk), rolipram (Rol), and dibutyryl cAMP (dbcAMP) ((b) and (d)). Where indicated, iNOS inhibitor aminoguanidine (AmGua), 10−4 M, was used, alone or in combination with these various agonists. All agents were present from the beginning of culture for a 7-day period. Data (mean + SEM; in (a), remaining panels) are the numbers of EPO+ cells recovered at the end of the culture. Significant differences relative to the respective IL-5 controls: , , , .
