TY - JOUR
T1 - Lipoxin A4 inhibits IL-1β-induced IL-6, IL-8, and matrix metalloproteinase-3 production in human synovial fibroblasts and enhances synthesis of tissue inhibitors of metalloproteinases
AU - Sodin-Semrl, Snezna
AU - Taddeo, Brunella
AU - Tseng, Daniel
AU - Varga, John
AU - Fiore, Stefano
PY - 2000/3/1
Y1 - 2000/3/1
N2 - Lipoxins are a novel class of endogenous eicosanoid mediators that potently inhibit inflammatory events by signaling via specific receptors expressed on phagocytic cells. Animal models have shown that lipoxin A4 (LXA4) down-regulates inflammation in vivo. Here we demonstrate, for the first time, the expression of LXA4 receptors, and their up-regulation by IL- 1β, in normal human synovial fibroblasts (SF). We examined whether exogenous LXA4 abrogated IL-1β stimulation of SF in vitro. IL-1β induced the synthesis of IL-6, IL-8, and matrix metalloproteinases (MMP)-1 and -3. At nanomolar concentrations, LXA4 inhibited these IL-1β responses with reduction of IL-6 and IL-8 synthesis, by 45 ± 7% and 75 ± 11%, respectively, and prevented IL-1β-induced MMP-3 synthesis without significantly affecting MMP-1 levels. Furthermore, LXA4 induced a 2-fold increase of tissue inhibitor of metalloproteinase (TIMP)-1 and a ~3-fold increase of TIMP-2 protein levels. LXA4 inhibitory responses were dose dependent and were abrogated by pretreatment with LXA4 receptor antiserum. LXA4-induced changes of IL-6 and TIMP were accompanied by parallel changes in mRNA levels. These results indicate that LXA4 in activated SF inhibits the synthesis of inflammatory cytokines and MMP and stimulates TIMP production in vitro. These findings suggest that LXA4 may be involved in a negative feedback loop opposing inflammatory cytokine-induced activation of SF.
AB - Lipoxins are a novel class of endogenous eicosanoid mediators that potently inhibit inflammatory events by signaling via specific receptors expressed on phagocytic cells. Animal models have shown that lipoxin A4 (LXA4) down-regulates inflammation in vivo. Here we demonstrate, for the first time, the expression of LXA4 receptors, and their up-regulation by IL- 1β, in normal human synovial fibroblasts (SF). We examined whether exogenous LXA4 abrogated IL-1β stimulation of SF in vitro. IL-1β induced the synthesis of IL-6, IL-8, and matrix metalloproteinases (MMP)-1 and -3. At nanomolar concentrations, LXA4 inhibited these IL-1β responses with reduction of IL-6 and IL-8 synthesis, by 45 ± 7% and 75 ± 11%, respectively, and prevented IL-1β-induced MMP-3 synthesis without significantly affecting MMP-1 levels. Furthermore, LXA4 induced a 2-fold increase of tissue inhibitor of metalloproteinase (TIMP)-1 and a ~3-fold increase of TIMP-2 protein levels. LXA4 inhibitory responses were dose dependent and were abrogated by pretreatment with LXA4 receptor antiserum. LXA4-induced changes of IL-6 and TIMP were accompanied by parallel changes in mRNA levels. These results indicate that LXA4 in activated SF inhibits the synthesis of inflammatory cytokines and MMP and stimulates TIMP production in vitro. These findings suggest that LXA4 may be involved in a negative feedback loop opposing inflammatory cytokine-induced activation of SF.
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U2 - 10.4049/jimmunol.164.5.2660
DO - 10.4049/jimmunol.164.5.2660
M3 - Article
C2 - 10679106
AN - SCOPUS:0034144689
SN - 0022-1767
VL - 164
SP - 2660
EP - 2666
JO - Journal of Immunology
JF - Journal of Immunology
IS - 5
ER -