title: TLR-activated conventional DCs promote γ-secretase-mediated conditioning of plasmacytoid DCs.
abstract: Cooperative events between DC subsets involve cell contact and soluble factors. Upon viral challenge, murine pDCs induce cDC cooperation through CD40-CD40L interactions and IL-15 secretion, whereas in humans, the same effect is mediated by IFN-α. Conversely, during bacterial infections, pDC maturation may be induced by activated cDCs, although no mechanisms had been described so far. Here, we investigate how human pDCs are "conditioned" by cDCs. Blood-borne DC subsets (cDCs and pDCs) were sorted from healthy donors. IL-3-maintained pDCs were cocultured with LPS-activated, poly (I:C)-activated, or control cDCs [cDC(LPS), cDC(P(I:C)), cDC(CTRL)]. Coculture experiments showed that cDC(LPS)-conditioned pDCs up-regulated maturation markers, such as CD25 and CD86, whereas SNs contained higher amounts of IL-6 and CCL19 compared with control conditions. Gene-expression analyses on sorted cDC(LPS) or cDC(P(I:C)) conditioned pDCs confirmed the induction of several genes, including IL-6 and CCL19 and remarkably, several Notch target genes. Further studies using the γ-secretase/Notch inhibitor DAPT and soluble Notch ligands resulted in a significantly reduced expression of canonical Notch target genes in conditioned pDCs. DAPT treatment also hampered the secretion of CCL19 (but not of IL-6) by cDC(LPS) conditioned pDCs. These results reveal the involvement of γ-secretase-mediated mechanisms, including the Notch pathway, in the cell contact-dependent communication between human DC subsets. The resulting partial activation of pDCs after encountering with mature cDCs endows pDCs with an accessory function that may contribute to T cell recruitment and activation.
authors.affiliation: Laboratori d’Immunobiologia i Diagnòstic Molecular (LIRAD), Banc de Sang i Teixits (BST), Departament de BiologiaCel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, Institut d’Investigació Germans Trias i Pujol, Barcelona, Spain.
authors.forename: Begoña
authors.initials: B
authors.lastname: Pérez-Cabezas
authors.forename: Mar
authors.initials: M
authors.lastname: Naranjo-Gómez
authors.forename: Marta
authors.initials: M
authors.lastname: Ruiz-Riol
authors.forename: Patricia
authors.initials: P
authors.lastname: Bastos-Amador
authors.forename: Marco A
authors.initials: MA
authors.lastname: Fernández
authors.forename: Francesc
authors.initials: F
authors.lastname: Carmona
authors.forename: Fatima
authors.initials: F
authors.lastname: Nuñez
authors.forename: Ricardo
authors.initials: R
authors.lastname: Pujol-Borrell
authors.forename: Francesc E
authors.initials: FE
authors.lastname: Borràs
mesh_terms: D053829:Amyloid Precursor Protein Secretases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D002450:Cell Communication; D002465:Cell Movement; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D020869:Gene Expression Profiling; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D008223:Lymphoma / Q000276:immunology* / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D051880:Receptors, Notch / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013959:Thyroid Diseases / Q000276:immunology* / Q000378:metabolism; D051193:Toll-Like Receptors / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D016207:Cytokines; D007377:Interleukin-3; D012333:RNA, Messenger; D051880:Receptors, Notch; D051193:Toll-Like Receptors; D053829:Amyloid Precursor Protein Secretases