title: Soybean-derived Bowman-Birk inhibitor inhibits neurotoxicity of LPS-activated macrophages.
abstract: BACKGROUND
  Lipopolysaccharide (LPS), the major component of the outer membrane of gram-negative bacteria, can activate immune cells including macrophages. Activation of macrophages in the central nervous system (CNS) contributes to neuronal injury. Bowman-Birk inhibitor (BBI), a soybean-derived protease inhibitor, has anti-inflammatory properties. In this study, we examined whether BBI has the ability to inhibit LPS-mediated macrophage activation, reducing the release of pro-inflammatory cytokines and subsequent neurotoxicity in primary cortical neural cultures.
  
  
  METHODS
  Mixed cortical neural cultures from rat were used as target cells for testing neurotoxicity induced by LPS-treated macrophage supernatant. Neuronal survival was measured using a cell-based ELISA method for expression of the neuronal marker MAP-2. Intracellular reactive oxygen species (ROS) production in macrophages was measured via 2', 7'-dichlorofluorescin diacetate (DCFH2DA) oxidation. Cytokine expression was determined by quantitative real-time PCR.
  
  
  RESULTS
  LPS treatment of macrophages induced expression of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) and of ROS. In contrast, BBI pretreatment (1-100 μg/ml) of macrophages significantly inhibited LPS-mediated induction of these cytokines and ROS. Further, supernatant from BBI-pretreated and LPS-activated macrophage cultures was found to be less cytotoxic to neurons than that from non-BBI-pretreated and LPS-activated macrophage cultures. BBI, when directly added to the neuronal cultures (1-100 μg/ml), had no protective effect on neurons with or without LPS-activated macrophage supernatant treatment. In addition, BBI (100 μg/ml) had no effect on N-methyl-D-aspartic acid (NMDA)-mediated neurotoxicity.
  
  
  CONCLUSIONS
  These findings demonstrate that BBI, through its anti-inflammatory properties, protects neurons from neurotoxicity mediated by activated macrophages.
authors.affiliation: Department of Pathology & Laboratory Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
authors.forename: Jieliang
authors.initials: J
authors.lastname: Li
authors.forename: Li
authors.initials: L
authors.lastname: Ye
authors.forename: Denise R
authors.initials: DR
authors.lastname: Cook
authors.forename: Xu
authors.initials: X
authors.lastname: Wang
authors.forename: Jinping
authors.initials: J
authors.lastname: Liu
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Kolson
authors.forename: Yuri
authors.initials: Y
authors.lastname: Persidsky
authors.forename: Wen-Zhe
authors.initials: WZ
authors.lastname: Ho
mesh_terms: D000818:Animals; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002490:Central Nervous System / Q000276:immunology; D016207:Cytokines / Q000276:immunology; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000276:immunology / Q000502:physiology*; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020258:Neurotoxicity Syndromes / Q000276:immunology; D018384:Oxidative Stress; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000494:pharmacology*
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D017382:Reactive Oxygen Species; D014358:Trypsin Inhibitor, Bowman-Birk Soybean