In:
Journal of Leukocyte Biology, Oxford University Press (OUP), Vol. 96, No. 4 ( 2014-07-02), p. 611-618
Abstract:
Thrombin is not only a central factor in blood coagulation but also stimulates inflammatory processes, including monocyte responses, via activation of PARs. The signaling lipid S1P is a major determinant of monocyte function. Here, we established an interaction between S1P and human monocyte responses to thrombin. S1P induced PAR-1 and PAR-4 mRNA and total protein expression in human monocytes and U937 cells in a concentration (0.1–10 μM)- and time (1–24 h)-dependent manner, respectively. However, only PAR-4 cell-surface expression was increased significantly by S1P, whereas PAR-1 remained unaffected. This response was associated with activation of the Akt, Erk, and p38 pathway and induction of COX-2 but not COX-1. PAR-4-mediated induction of COX-2 was prevented by the PI3K inhibitor LY (10 μM). Preincubation of human monocytes with S1P (1 μM; 16 h) resulted in an enhanced chemotaxis toward thrombin or to selective AP for PAR-4 but not PAR-1. Furthermore, down-regulation of PAR-4 transcription with siRNA attenuated the chemotactic response to thrombin and AP4. In conclusion, S1P enhances monocyte responses to thrombin via up-regulation of PAR-4 expression, which promotes cell migration and COX-2 abundance. This mechanism may facilitate monocyte recruitment to sites of vessel injury and inflammation.
Type of Medium:
Online Resource
ISSN:
0741-5400
,
1938-3673
DOI:
10.1189/jlb.3AB1013-567R
Language:
English
Publisher:
Oxford University Press (OUP)
Publication Date:
2014
detail.hit.zdb_id:
2026833-6
SSG:
12
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