TY - JOUR
T1 - TLR-activated conventional DCs promote γ-secretase-mediated conditioning of plasmacytoid DCs
AU - Pérez-Cabezas, Begoña
AU - Naranjo-Gómez, Mar
AU - Ruiz-Riol, Marta
AU - Bastos-Amador, Patricia
AU - Fernández, Marco A.
AU - Carmona, Francesc
AU - Nuñez, Fatima
AU - Pujol-Borrell, Ricardo
AU - Borràs, Francesc E.
PY - 2012/7/1
Y1 - 2012/7/1
N2 - 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 cocul-tured with LPS-activated, poly (I:C)-activated, or control cDCs [cDCLPS, cDCP(I:C), cDCCTRL]. Coculture experiments showed that cDCLPS-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 cDCLPS or cDCP(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 cDCLPS 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. © Society for Leukocyte Biology.
AB - 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 cocul-tured with LPS-activated, poly (I:C)-activated, or control cDCs [cDCLPS, cDCP(I:C), cDCCTRL]. Coculture experiments showed that cDCLPS-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 cDCLPS or cDCP(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 cDCLPS 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. © Society for Leukocyte Biology.
KW - γ-secretase
KW - CCL19
KW - Cooperation
KW - Dendritic cells
KW - Human
KW - Notch
U2 - 10.1189/jlb.0911452
DO - 10.1189/jlb.0911452
M3 - Article
VL - 92
SP - 133
EP - 143
JO - Journal of Leukocyte Biology
JF - Journal of Leukocyte Biology
SN - 0741-5400
IS - 1
ER -