Activated protein C inhibits lipopolysaccharide‐induced nuclear translocation of nuclear factor κB (NF‐κB) and tumour necrosis factor α (TNF‐α) production in the THP‐1 monocytic cell line

Abstract

Summary. Activated protein C (APC) protects against sepsis in animal models and inhibits the lipopolysacharide (LPS)-induced elaboration of proinflammatory cytokines from monocytes. The molecular mechanism responsible for this property is unknown. We assessed the effect of APC on LPS-induced tumour necrosis factor a (TNF-a) production and on the activation of the central proinflammatory transcription factor nuclear factor-kB (NF-kB) in a THP-1 cell line. Cells were preincubated with varying concentrations of APC (200 mg/ml, 100 mg/ml and 20 mg/ml) before addition of LPS (100 ng/ml and 10 mg/ml). APC inhibited LPS-induced production of TNFa both in the presence and absence of fetal calf serum (FCS), although the effect was less marked with 10% FCS. APC also inhibited LPS-induced activation of NF-kB, with APC (200 mg/ ml) abolishing the effect of LPS (100 ng/ml). The ability of APC to inhibit LPS-induced translocation of NF-kB is likely to be a significant event given the critical role of the latter in the host inflammatory response.

Modulation of Monocyte Function by Activated Protein C, a Natural Anticoagulant

“…Although ILs 10 and 12p70 were assayed with the CBA, no treatment group expressed either cytokine at concentrations exceeding 10 pg/ml (data not shown). We also observed a minor but significant 8% down-regulation of THP-1 TNF expression by 120 nM activated protein C. Such a small effect may appear inconsistent with previously published results that revealed inhibitions exceeding 50% (14). However, activated protein C concentrations in these previous studies exceeded 3.6 M, representing a probable cause for this discrepancy.…”

“…sepsis receiving recombinant activated protein C contained reduced levels of IL-6 (4). In vitro studies have also revealed that 360 nM and 3.6 M activated protein C inhibited TNF-␣ secretion by CD14 ϩ peripheral monocytes and by THP-1 cells, respectively (14,15). However, the regulated secretion of numerous other cytokines by activated protein C-treated monocytes has not been documented to date.…”

“…More recently, activated protein C has been shown to inhibit inflammation (13)(14)(15)(16)(17)(18), apoptosis (19 -22), and to prevent increases in vascular permeability (23,24). With respect to its antiinflammatory properties, activated protein C has been shown to down-regulate the production of TNF by monocytes (13)(14)(15) and to suppress expression of leukocyte adhesion molecules in endothelial cells (16), presumably by inhibiting NF-B nuclear translocation (14) and/or down-regulating the transcription of NF-B subunits (16).…”

“…With respect to its antiinflammatory properties, activated protein C has been shown to down-regulate the production of TNF by monocytes (13)(14)(15) and to suppress expression of leukocyte adhesion molecules in endothelial cells (16), presumably by inhibiting NF-B nuclear translocation (14) and/or down-regulating the transcription of NF-B subunits (16). In animals challenged with endotoxin, activated protein C inhibited the production of proinflammatory cytokines (17,18) and inhibited leukocyte accumulation in injured tissue (25).…”

MMUNOHISTOCHEMICAL ANALYSIS OF NF-kB (P0/P) IN PATIENT WITH AGGRESSIVE AND CHRONIC PERIODONTITIS

“…NF-κB is activated by LPS in THP-1 cells, the transcription factor NF-kB is associated with metabolic and inflammatory responses, including nuclear receptors, activators of protein (AP-1) and early growth response (EGR). Furthermore, it is suggested that IKK/NF-kB is a target for the treatment of periodontitis disorders (White et al, 2000;Carpenter andO'Neill., 2007, Chen, 2007). As it was believed that the expression of NF-kB (p50/p65) affects the occurrence of aggressive and chronic periodontitis, this study revealed observations of its expression in patients with those disorders.…”