title: CC chemokine ligand 2 down-modulation by selected Toll-like receptor agonist combinations contributes to T helper 1 polarization in human dendritic cells.
abstract: Toll-like receptor (TLR) signaling activation by pathogens is critical to the induction of immune responses, and demands tight regulation. We describe in this study that CC chemokine ligand 2 (CCL2) secretion triggered by TLR4 or TLR8 engagement is strongly inhibited upon simultaneous activation of both TLRs in human monocyte-derived dendritic cells (DCs). Impaired CCL2 secretion occurs concomitantly to interleukin-12 up-regulation, being part of a complex regulatory circuit ensuring optimal T helper type 1 polarization. Interestingly, triggering selected TLRs or their combinations differently affects nuclear factor-kappaB p65 activation and microRNA expression. Overall, these results indicate that CCL2 supplies an important immunomodulatory role to DCs, and may contribute to dictate the cytokine profile in T helper type 1 responses induced by DCs.
authors.affiliation: Department of Cell Biology and Neurosciences, Istituto Superiore di Sanità, Viale Regina Elena 299, Rome, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Del Cornò
authors.forename: Alessandro
authors.initials: A
authors.lastname: Michienzi
authors.forename: Andrea
authors.initials: A
authors.lastname: Masotti
authors.forename: Letizia
authors.initials: L
authors.lastname: Da Sacco
authors.forename: Gian Franco
authors.initials: GF
authors.lastname: Bottazzo
authors.forename: Filippo
authors.initials: F
authors.lastname: Belardelli
authors.forename: Sandra
authors.initials: S
authors.lastname: Gessani
mesh_terms: D016764:Cell Polarity / Q000187:drug effects*; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D003713:Dendritic Cells / Q000187:drug effects* / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004338:Drug Combinations; D006801:Humans; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology; D016899:Interferon-beta / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000494:pharmacology; D011070:Poly I-C / Q000008:administration & dosage / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D018417:Th1 Cells / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D051193:Toll-Like Receptors / Q000819:agonists*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D018932:Chemokine CCL2; D004338:Drug Combinations; D007093:Imidazoles; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D051193:Toll-Like Receptors; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D016899:Interferon-beta; D011070:Poly I-C; C402365:resiquimod