Identification of synthetic peptides that inhibit lipopolysaccharide (LPS) binding to myeloid differentiation protein-2 (MD-2)

• Published in: Journal of immunotherapy (1997) Vol. 36; no. 3; p. 197
• Main Authors: Yan, Hong, Gu, Chang-Guo, Xu, Fa-Liang, Wu, Xiao-Hua, Yin, Hua-Hua, Hu, Cheng-Xiang, Zhu, Xu-Dong, Liu, Feng, Ge, Heng-Jiang, Chen, Li-Yong, Zhang, Xin-Yan, Wang, Zheng-Guo, Xing, Zhou, Li, Lei
• Format: Journal Article
• Language: English
• Published: United States 01.04.2013
• Subjects: Amino Acid Sequence; Animals; Binding Sites; Cell Line; Enzyme Activation; Genetic Vectors; Humans; Interleukin-6 - biosynthesis; Lipopolysaccharides - metabolism; Lymphocyte Antigen 96 - chemistry; Lymphocyte Antigen 96 - metabolism; Macrophages - immunology; Macrophages - metabolism; Male; Mice; Mice, Inbred BALB C; NF-kappa B - metabolism; Peptide Library; Peptides - chemistry; Peptides - pharmacology; Protein Binding; Signal Transduction; Toll-Like Receptor 4 - metabolism; Transcription Factor RelA - metabolism; Tumor Necrosis Factor-alpha - biosynthesis
• ISSN: 1537-4513
• DOI: 10.1097/CJI.0b013e31828eed62

Many studies have suggested that the synergic effect of myeloid differential protein-2 (MD-2) on bacterial lipopolysaccharide (LPS) stimulation of toll-like receptor 4 (TLR4) may be a critical step during the LPS-TLR4 response signaling pathway. We performed a bioinformatic analysis on the MD-2 protein and identified the amino acid sequence NH2-FSKGKYKCV-COOH (K128-132) as a possible key sequence involved in the binding between MD-2 and LPS. We then screened a random phage display peptide library using this sequence as bait in order to identify antagonistic peptides. After 3 rounds of selection, 3 positive clones were identified. All 3 peptides were shown to inhibit, in a dose-dependent manner the production of tumor necrosis factor-α and interleukin-6 in human U937 and THP-1 cell lines as well as human peripheral blood monocytes stimulated by LPS. Only 2 of the 3 peptides were able to bind MD-2 directly as shown by sulfo-SBED biotin label transfer experiments. BALB/C mice were used to estimate the protection of these peptides from LPS challenge, and 2 of the 3 peptides (Lys-Thr-Val-Pro-Asp-Asn-His and Ile-Gly-Lys-Phe-Leu-Tyr-Arg) reduced mortality of the challenged mice from 100% to 53.8%. This study has demonstrated that interfering with the binding between MD-2 and LPS might be a potential therapeutic strategy for treating LPS-induced sepsis, and in doing so has identified 2 potential peptide candidates.