Activated protein C induction of MCP-1 in human endothelial cells: a possible role for endothelial cell nitric oxide synthase.
Classically, activated protein C (APC) of the protein C/protein S anticoagulant pathway has functioned not only to inactivate the procoagulant factors Va and VIIIa but also to inhibit the activity of plasminogen activator inhibitor-1 (PAI-1). More recent data have suggested that the protein C/protein S pathway may serve as a physiological link between coagulation and inflammation. This APC pathway link was proposed because of observations showing that APC could both modulate the effects of cytokines and block neutrophil activation. As a further extension of the effect(s) of APC on cytokines, we found that APC, at the equivalent physiological protein C concentration of 4 microg/ml, significantly upregulated monocyte chemotactic protein-1 (MCP-1) RNA in human umbilical vein endothelial cells (HUVECs), as indicated by a ribonuclease protection assay (RPA) at 3 and 6 h with a return to near basal levels by 24 h. ELISA determinations demonstrated that 4 microg/ml of APC induced a significant (P=.0001) increase in MCP-1 protein production over basal levels within a 24-h period. At the same concentration, APC downregulated endothelial cell nitric oxide synthase (eNOS) RNA. Downregulation first became apparent at 6 h and continued through 48 h of culture. This downregulation was concentration dependent over a range of 1.3-12 microg/ml, and there was no effect on cell viability within this range. In support of other studies, we also found that exogenously added nitric oxide (NO) inhibited MCP-1 production. These data suggest that APC may induce MCP-1 through the inhibition of eNOS.
Hooper
W C
WC
Hematologic Diseases Branch, Division of AIDS, STD and TB Laboratory Research, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA. chooper@cdc.gov
Phillips
D J
DJ
Renshaw
M A
MA
D018932:Chemokine CCL2 / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D006801:Humans; D007118:Immunoassay; D007700:Kinetics; D019001:Nitric Oxide Synthase / Q000235:genetics / Q000502:physiology; D052250:Nitric Oxide Synthase Type III; D011486:Protein C / Q000378:metabolism / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D014471:Umbilical Veins; D015854:Up-Regulation / Q000187:drug effects
D018932:Chemokine CCL2; D005343:Fibrinolytic Agents; D011486:Protein C; D012333:RNA, Messenger; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III