title: Reducing glycosphingolipid biosynthesis in airway cells partially ameliorates disease manifestations in a mouse model of asthma.
abstract: Lipid rafts reportedly play an important role in modulating the activation of mast cells and granulocytes, the primary effector cells of airway hyperresponsiveness and asthma. Activation is mediated through resident signaling molecules whose activity, in part, may be modulated by the composition of glycosphingolipids (GSLs) in membrane rafts. In this study, we evaluated the impact of inhibiting GSL biosynthesis in mast cells and in the ovalbumin (OVA)-induced mouse model of asthma using either a small molecule inhibitor or anti-sense oligonucleotides (ASOs) directed against specific enzymes in the GSL pathway. Lowering GSL levels in mast cells through inhibition of glucosylceramide synthase (GCS) reduced phosphorylation of Syk tyrosine kinase and phospholipase C gamma 2 (PLC-gamma2) as well as cytoplasmic Ca(2+) levels. Modulating these intracellular signaling events also resulted in a significant decrease in mast cell degranulation. Primary mast cells isolated from a GM3 synthase (GM3S) knockout mouse exhibited suppressed activation-induced degranulation activity further supporting a role of GSLs in this process. In previously OVA-sensitized mice, intra-nasal administration of ASOs to GCS, GM3S or lactosylceramide synthase (LCS) significantly suppressed metacholine-induced airway hyperresponsiveness and pulmonary inflammation to a subsequent local challenge with OVA. However, administration of the ASOs into mice that had been sensitized and locally challenged with the allergen did not abate the consequent pulmonary inflammatory sequelae. These results suggest that GSLs contribute to the initiation phase of the pathogenesis of airway hyperreactivity and asthma and lowering GSL levels may offer a novel strategy to modulate these manifestations.
authors.affiliation: Genzyme Corporation, 49 New York Avenue, Framingham, MA 01701, USA. jozsef.karman@genzyme.com
authors.forename: Jozsef
authors.initials: J
authors.lastname: Karman
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Tedstone
authors.forename: Nathan K
authors.initials: NK
authors.lastname: Gumlaw
authors.forename: Yunxiang
authors.initials: Y
authors.lastname: Zhu
authors.forename: Nelson
authors.initials: N
authors.lastname: Yew
authors.forename: Craig
authors.initials: C
authors.lastname: Siegel
authors.forename: Shuling
authors.initials: S
authors.lastname: Guo
authors.forename: Andrew
authors.initials: A
authors.lastname: Siwkowski
authors.forename: Melanie
authors.initials: M
authors.lastname: Ruzek
authors.forename: Canwen
authors.initials: C
authors.lastname: Jiang
authors.forename: Seng H
authors.initials: SH
authors.lastname: Cheng
mesh_terms: D000818:Animals; D001249:Asthma / Q000188:drug therapy / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology*; D015550:Cell Degranulation / Q000187:drug effects; D004146:Dioxanes / Q000494:pharmacology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors; D006028:Glycosphingolipids / Q000096:biosynthesis* / Q000276:immunology; D008407:Mast Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008970:Molecular Weight; D016376:Oligonucleotides, Antisense / Q000008:administration & dosage / Q000494:pharmacology; D010047:Ovalbumin / Q000276:immunology; D051966:Phospholipase C gamma / Q000037:antagonists & inhibitors / Q000276:immunology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000276:immunology; D011759:Pyrrolidines / Q000494:pharmacology; D012799:Sialyltransferases / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology
chemical_list: C520404:(2-(2',3'-dihydrobenzo(1,4)dioxin-6'-yl)-2-hydroxy-1-pyrrolidin-1-ylmethylethyl)nonanoic acid amide; D004146:Dioxanes; D006028:Glycosphingolipids; D016376:Oligonucleotides, Antisense; D011759:Pyrrolidines; D010047:Ovalbumin; D005964:Glucosyltransferases; C023246:ceramide glucosyltransferase; D012799:Sialyltransferases; C021343:haematoside synthetase; D011505:Protein-Tyrosine Kinases; D051966:Phospholipase C gamma