In:
Blood, American Society of Hematology, Vol. 116, No. 18 ( 2010-11-04), p. 3389-3397
Abstract:
Microbial infection triggers the endogenous production of immunosuppressive glucocorticoid (GC) hormones and simultaneously activates innate immunity through toll-like receptors (TLRs). How innate immune cells integrate these 2 opposing signals in dictating immunity or tolerance to infection is not known. In this study, we show that human plasmacytoid predendritic cells (pDCs) were highly sensitive to GC-induced apoptosis. Strikingly, they were protected by microbial stimulation through TLR-7 and TLR-9, but not by microbial-independent stimuli, such as interleukin-3, granulocyte macrophage colony-stimulating factor, or CD40-ligand. This protection was dependent on TLR-induced autocrine tumor necrosis factor-α and interferon-α, which collectively increased the expression ratio between antiapoptotic genes (Bcl-2, Bcl-xL, BIRC3, CFLAR) versus proapoptotic genes (Caspase-8, BID, BAD, BAX). In particular, virus-induced Bcl-2 up-regulation was dependent on autocrine interferon-α. Using small interfering RNA technology, we demonstrated that Bcl-2 and CFLAR/c-flip were essential for TLR-induced protection of pDCs from GC-induced caspase-8–mediated apoptosis. Our results demonstrate a novel property of the TLR pathway in regulating the interface between GC and innate immunity and reveal a previously undescribed mechanism of GC resistance.
Type of Medium:
Online Resource
ISSN:
0006-4971
,
1528-0020
DOI:
10.1182/blood-2010-05-282913
Language:
English
Publisher:
American Society of Hematology
Publication Date:
2010
detail.hit.zdb_id:
1468538-3
detail.hit.zdb_id:
80069-7
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