Effects of CD14 inhibitory peptide on TNF-α expression of U937 induced by lipopolysaccharides

Objective To investigate the effects of CD14 inhibitory peptide(CD14-IP)on TNF-α expression of U937 induced by lipopolysaccharides(LPS).Methods U937 cells were stimulated by Phorbol myristate acetate(PMA),and then divided into five groups:control group,LPS group,high dose inhibitory peptide(HIP)group,moderate dose inhibitory peptide(MIP)group,and low dose inhibitory peptide(LIP)group.The cells in LPS group were incubated with 100 ng/mL(final concentration)LPS and 100 ng/mL(final concentration)LBP.The cells in HIP,MIP,and LIP groups were incubated with 10,1.0,and 0.1 μg/mL CD14-IP respectively,besides LPS and LBP.The concentration of TNF-α released from cultured cells was detected by ELISA.Subsequently,U937 cells were incubated with 1.0 μg/mL CD14-IP.After treatment for different times,the mRNA and protein expression levels of TNF-α in each treatment point were determined by RT-PCR and ELISA,respectively.Results The concentrations of TNF-α in LPS group and every CD14-IP group were significantly higher than that in control group(P0.05).Compared with LPS group,the TNF-α protein expressions in HIP and MIP groups were significantly reduced(P0.05).There was not significant difference in the concentration of TNF-α between HIP and MIP groups(P0.05).The concentration of TNF-α in LPS group was not significantly higher than that in LIP group(P0.05).After treatment with CD14-IP,the expressions of TNF-α and TNF-α mRNA decreased in a time-dependent manner,compared with LPS group.Conclusion CD14-IP can reduce the TNF-α mRNA and protein expression of U937 induced by lipopolysaccharide in a time-dependent manner,which suggests a potential protective effects of CD14-IP against LPS-induced inflammatory disorders such as acute lung injury.