title: Kukoamine B promotes TLR4-independent lipopolysaccharide uptake in murine hepatocytes.
abstract: Free bacterial lipopolysaccharide (LPS) is generally removed from the bloodstream through hepatic uptake via TLR4, the LPS pattern recognition receptor, but mechanisms for internalization and clearance of conjugated LPS are less clear. Kukoamine B (KB) is a novel cationic alkaloid that interferes with LPS binding to TLR4. In this study, KB accelerated blood clearance of LPS. KB also enhanced LPS distribution in the hepatic tissues of C57 BL/6 mice, along with LPS uptake in primary hepatocytes and HepG2 cells. By contrast, KB inhibited LPS internalization in Kupffer and RAW 264.7 cells. Loss of TLR4 did not affect LPS uptake into KB-treated hepatocytes. We also detected selective upregulation of the asialoglycoprotein receptor (ASGPR) upon KB treatment, and ASGPR colocalized with KB in cultured hepatocytes. Molecular docking showed that KB bound to ASGPR in a manner similar to GalNAc, a known ASGPR agonist. GalNAc dose-dependently reduced KB internalization, suggesting it competes with KB for ASGPR binding, and ASGPR knockdown also impaired LPS uptake into hepatocytes. Finally, while KB enhanced LPS uptake, it was protective against LPS-induced inflammation and hepatocyte injury. Our study provides a new mechanism for conjugated LPS hepatic uptake induced by the LPS neutralizer KB and mediated by membrane ASGPR binding.
authors.affiliation: Medical Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Yang
authors.affiliation: Medical Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Xinchuan
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Medical Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.affiliation: Medical Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Shijun
authors.initials: S
authors.lastname: Fan
authors.affiliation: Medical Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Medical Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Yongling
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Medical Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Chen
authors.affiliation: Medical Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
authors.affiliation: Medical Research Center, Southwest Hospital, Third Military Medical University, Chongqing, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Zheng
mesh_terms: D000818:Animals; D037263:Asialoglycoprotein Receptor / Q000378:metabolism; D015374:Biosensing Techniques; D002109:Caffeic Acids / Q000494:pharmacology*; D005434:Flow Cytometry; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007249:Inflammation; D007728:Kupffer Cells / Q000378:metabolism; D008070:Lipopolysaccharides / Q000378:metabolism*; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D062105:Molecular Docking Simulation; D013096:Spermine / Q000031:analogs & derivatives* / Q000494:pharmacology; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*
chemical_list: D037263:Asialoglycoprotein Receptor; D002109:Caffeic Acids; D008070:Lipopolysaccharides; C495345:TLR4 protein, human; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; C557784:kukoamine B; D013096:Spermine
keywords: Immunology and Microbiology Section; asialoglycoprotein receptor; hepatocytes; kukoamine B; lipopolysaccharide; Immune response; Immunity