[Ac-hE-18A-NH2 inhibits the inflammatory response induced by ox-LDL via inhibiting NF-κB activation in RAW264.7 macrophages].

OBJECTIVE

To evaluate the effect of Ac-hE-18A-NH2 on TNF-α secretion and mRNA expression in ox-LDL-stimulated RAW264.7 macrophages and to elucidate the possible mechanisms.

METHODS

Macrophages were incubated in the medium containing various concentrations of Ac-hE18A-NH2 (1-50 μg/mL) with ox-LDL (50 μg/mL) stimulated. The TNF-α level and intracellular cholesterol content were measured by commercially available quantitation kits following the manufacturer's instructions. TNF-α and ATP-binding cassette transporter A1 (ABCA1) mRNA expression were detected by real-time PCR. ABCA1 and IκB protein -expression in the macrophages were determined by Western blot. NF-κB activity was evaluated by electrophoretic mobility shift assay (EMSA).

RESULTS

Ox-LDL stimulation induced a significant increase in TNF-α secretion, mRNA expression, cholesterol accumulation and nuclear factor-κB (NF-κB) activity in RAW264.7 macrophages. Ac-hE-18A-NH2 reduced TNF-α secretion and mRNA expression, up-regulated the ABCA1 mRNA and protein expression, reduced the intracellular cholesterol content, and inhibited NF- κB activation in a dose-dependent manner. Under the same condition and the same concentration, Ac-hE-18A-NH2 was more efficient than D-4F (apoA-I mimetic peptide) in inhibiting the inflammatory response induced by ox-LDL in the macrophages.

CONCLUSION

Ac-hE-18A-NH2 may suppress TNF-α secretion and mRNA expression in ox-LDL stimulated RAW264.7 macrophages via IκB-NF-κB signaling pathway. The anti-inflammatory effect of Ac-hE-18A-NH2 is better than that of apoA-I mimic peptide D-4F.