Inhibitory effects of a novel cationic dodecapeptide [CL(14–25)] derived from cyanate lyase of rice on endotoxic activities of LPSs from Escherichia coli and periodontopathic Aggregatibacter actinomycetemcomitans

Abstract

ObjectiveCL(14–25), a dodecapeptide of cyanate lyase from rice, is a novel cationic α-helical antimicrobial peptide. In this study, we examined inhibitory ability of CL(14–25) against endotoxic activities of lipopolysaccharides (LPSs) from Escherichia coli and periodontal pathogenic Aggregatibacter actinomycetemcomitans. MethodsEndotoxin-neutralizing activity of CL(14–25) was evaluated by inhibition to induction of cytokine and nitric oxide in human aortic endothelial cells (HAECs) and RAW264 mouse macrophage cells, respectively. Protective effect of CL(14–25) was determined in mice against lethal toxicity of LPS. ResultsIL-6 in HAECs was induced by stimulation with LPS preparations of A. actinomycetemcomitans and E. coli tested in this study, and addition of CL(14–25) to the medium caused inhibition of their induction in a dose-dependent manner. CL(14–25) inhibited NO induction in RAW264 cells by a smooth type LPS of E. coli O55:B5 and an Rc type LPS of E. coli J5 as well as lipid A of E. coli R515 in a dose-dependent manner. Simultaneous injection of E. coli O55:B5 LPS and CL(14–25) in BALB/c mice resulted in prevention of lethal toxicity of the former. The results of a Limulus amebocyte lysate assay and surface plasmon resonance analysis of interaction between CL(14–25) and E. coli LPS or lipid A showed that CL(14–25) specifically binds to a lipid A moiety of LPS. ConclusionThe results of present study suggest that CL(14–25) has a potential to be used as a nutraceutical agent for periodontal therapy.