title: Paradoxical anti-inflammatory actions of TNF-alpha: inhibition of IL-12 and IL-23 via TNF receptor 1 in macrophages and dendritic cells.
abstract: IL-12 and TNF-alpha are central proinflammatory cytokines produced by macrophages and dendritic cells. Disregulation of TNF-alpha is associated with sepsis and autoimmune diseases such as rheumatoid arthritis. However, new evidence suggests an anti-inflammatory role for TNF-alpha. TNF-alpha-treated murine macrophages produced less IL-12p70 and IL-23, after stimulation with IFN-gamma and LPS. Frequency of IL-12p40-producing macrophages correspondingly decreased as measured by intracellular cytokine staining. IL-12p40 production was also inhibited in dendritic cells. TNFR1 was established as the main receptor involved in IL-12p40 regulation, because IL-12p40 levels were not affected by TNF-alpha in TNFR1(-/-)-derived macrophages. Macrophages activated during Listeria monocytogenes infection were more susceptible to inhibition by TNF-alpha than cells from naive animals, which suggests a regulatory role for TNF-alpha in later stages of infection. This nonapoptotic anti-inflammatory regulation of IL-12 and IL-23 is an important addition to the multitude of TNF-alpha-induced responses determined by cell-specific receptor signaling.
authors.affiliation: Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA 30322, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Zakharova
authors.forename: H Kirk
authors.initials: HK
authors.lastname: Ziegler
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000378:metabolism*; D018836:Inflammation Mediators / Q000502:physiology*; D018664:Interleukin-12 / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D053762:Interleukin-12 Subunit p40; D053759:Interleukin-23; D053760:Interleukin-23 Subunit p19; D007378:Interleukins / Q000037:antagonists & inhibitors*; D008088:Listeriosis / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D021122:Protein Subunits / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D013601:T-Lymphocytes / Q000166:cytology / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
chemical_list: C508841:Il23a protein, mouse; D018836:Inflammation Mediators; D053762:Interleukin-12 Subunit p40; D053759:Interleukin-23; D053760:Interleukin-23 Subunit p19; D007378:Interleukins; D021122:Protein Subunits; D047888:Receptors, Tumor Necrosis Factor, Type I; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12