title: Identification of synthetic peptides that inhibit lipopolysaccharide (LPS) binding to myeloid differentiation protein-2 (MD-2).
abstract: 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.
authors.affiliation: Department of Infection and Immunity, Research Institute of Surgery/Daping Hospital, Chongqing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Yan
authors.forename: Chang-Guo
authors.initials: CG
authors.lastname: Gu
authors.forename: Fa-Liang
authors.initials: FL
authors.lastname: Xu
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Wu
authors.forename: Hua-Hua
authors.initials: HH
authors.lastname: Yin
authors.forename: Cheng-Xiang
authors.initials: CX
authors.lastname: Hu
authors.forename: Xu-Dong
authors.initials: XD
authors.lastname: Zhu
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.forename: Heng-Jiang
authors.initials: HJ
authors.lastname: Ge
authors.forename: Li-Yong
authors.initials: LY
authors.lastname: Chen
authors.forename: Xin-Yan
authors.initials: XY
authors.lastname: Zhang
authors.forename: Zheng-Guo
authors.initials: ZG
authors.lastname: Wang
authors.forename: Zhou
authors.initials: Z
authors.lastname: Xing
authors.forename: Lei
authors.initials: L
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D004789:Enzyme Activation; D005822:Genetic Vectors; D006801:Humans; D015850:Interleukin-6 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000378:metabolism*; D051218:Lymphocyte Antigen 96 / Q000737:chemistry / Q000378:metabolism*; D008264:Macrophages / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000378:metabolism; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D011485:Protein Binding; D015398:Signal Transduction; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D051996:Transcription Factor RelA / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
chemical_list: D015850:Interleukin-6; D008070:Lipopolysaccharides; C411728:Ly96 protein, mouse; D051218:Lymphocyte Antigen 96; D016328:NF-kappa B; D019151:Peptide Library; D010455:Peptides; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha