Sodium Salicylate Modulates Inflammatory Responses Through AMP-activated Protein Kinase Activation In LPS-stimulated THP-1 Cells

【Background】 Sodium salicylate(Na Sal)is a nonsteroidal anti-inflammatory drug.The putative mechanisms for Na Sal’s pharmacologic action include the inhibition of cyclooxygenases,platelet-derived thromboxane A2 and NF-κB signaling.Recent studies demonstrated that salicylate could activate AMP-activated protein kinase(AMPK),an energy sensor that maintains the balance between ATP production and consumption.The anti-inflammatory action of AMPK has been reported to be mediated by promoting mitochondrial biogenesis and fatty acid oxidation.However,the exact signals responsible for salicylate-mediated inflammation through AMPK are not well-understood.【Purpose】 The purpose of this study was to investigate the potential effects of AMPK activated by Na Sal on inflammation-like responses of THP-1 monocytes to lipopolysaccharide(LPS)challenge.【Methods】 THP-1 cells were stimulated with or without 10ug/ml LPS for 24 h in the presence or absence of 5m M Na Sal.Apoptosis was measured by flow cytometry using Annexin V/PI staining and by western blotting for Bcl-2.Cell proliferation was detected by Ed U incorporation and b y western blot analysis for proliferating cell nuclear antigen(PCNA).Secretion of pro-inflammatory cytokines(TNF-α,IL-1β,and IL-6)was determined by enzyme-linked immunosorbent assay(ELISA).【Results】 Activation of AMPK by Na Sal was accompanied by induction of apoptosis,inhibition of cell proliferation and increasing secretion of TNF-α and IL-1β in LPS-stimulated THP-1 cells.These effects were reversed by Compound C,an inhibitor of AMPK.In addition,Na Sal/AMPK activation inhibited LPS-induced STAT3 phosphorylation,which was reversed by Compound C treatment.【Conclusion】 AMPK activation is important for Na Sal-mediated inflammation by inducing apoptosis,reducing cell proliferation,inhibiting STAT3 activity,and producing TNF-α and IL-1β.