| First Author | Bhattacharyya S | Year | 2011 |
| Journal | Proc Natl Acad Sci U S A | Volume | 108 |
| Issue | 23 | Pages | 9554-9 |
| PubMed ID | 21606371 | Mgi Jnum | J:173334 |
| Mgi Id | MGI:5013875 | Doi | 10.1073/pnas.1017296108 |
| Citation | Bhattacharyya S, et al. (2011) Glucocorticoids target suppressor of cytokine signaling 1 (SOCS1) and type 1 interferons to regulate Toll-like receptor-induced STAT1 activation. Proc Natl Acad Sci U S A 108(23):9554-9 |
| abstractText | Endogenous and pharmacologic glucocorticoids (GCs) limit inflammatory cascades initiated by Toll-like receptor (TLR) activation. A long-standing clinical observation has been the delay between GC administration and the manifestation of GC's anti-inflammatory actions. We hypothesized that the GCs would have inhibitory effects that target late temporal pathways that propagate proinflammatory signals. Here we interrogated signal transducer and activator of transcription 1 (STAT1) regulation by GC and its consequences for cytokine production during activation of macrophages with TLR-specific ligands. We found that robust STAT1 activation does not occur until 2-3 h after TLR engagement, and that GC suppression of STAT1 phosphorylation first manifests at this time. GC attenuates TLR4-mediated STAT1 activation only through induction of suppressor of cytokine signaling 1 (SOCS1), which increases throughout the 6-h period after treatment. Inhibition of TLR3-mediated STAT1 activation occurs via two mechanisms, impairment of type I IFN secretion and induction of SOCS1. Our data show that SOCS1 and type I interferons are critical GC targets for regulating STAT1 activity and may account for overall GC effectiveness in inflammation suppression in the clinically relevant time frame. |
