title: Biosurfactant mannosyl-erythritol lipid inhibits secretion of inflammatory mediators from RBL-2H3 cells.
abstract: BACKGROUND
  Biosurfactant mannosyl-erythritol lipids (MELs) are glycolipids produced by microbes that have various biological activities. It has been reported that MELs exhibit excellent surface-activity and also various bioactivities, such as induction of cell differentiation and apoptosis. However, little is known about their action related to drug discovery or drug seeds.
  
  
  METHODS
  We investigated the effects of MELs on the secretion of inflammatory mediators from mast cells that play a central role in allergic responses. Mast cells secrete three kinds of inflammatory mediators and we quantified these secreted mediators by photometer or ELISA. The action mechanisms of MELs were studied by Ca(2+)-sensitive fluorescence dye and Western blotting of phosphorylated proteins.
  
  
  RESULTS
  MELs inhibited exocytotic release by antigen stimulation in a dose-dependent manner. We also found that MELs inhibited antigen-induced secretion of leukotriene C(4) and cytokine TNF-α (tumor necrosis factor-α). The inhibitory action of MELs on mediator secretion was mediated by inhibition of Ca(2+) increase, phosphorylation of MAP kinases and SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) that serve as a molecular machinery for exocytotic membrane fusion.
  
  
  CONCLUSIONS
  MELs have anti-inflammatory action inhibiting the secretion of inflammatory mediators from mast cells.
  
  
  CONCLUSIONS
  MELs affects two of major intracellular signaling pathways including Ca(2+) increase and MAP kinases. MELs also inhibited the phosphorylation of SNARE proteins that is crucial for not only exocytosis but also intracellular vesicular trafficking.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Morita
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tadokoro
authors.forename: Masao
authors.initials: M
authors.lastname: Sasai
authors.forename: Dai
authors.initials: D
authors.lastname: Kitamoto
authors.forename: Naohide
authors.initials: N
authors.lastname: Hirashima
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D016207:Cytokines / Q000378:metabolism*; D004896:Erythritol / Q000494:pharmacology*; D005089:Exocytosis; D018836:Inflammation Mediators / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D013501:Surface-Active Agents / Q000494:pharmacology*
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D013501:Surface-Active Agents; D004896:Erythritol; D002118:Calcium