title: Abrogation of the Fc gamma receptor IIA-mediated phagocytic signal by stem-loop Syk antisense oligonucleotides.
abstract: The role of Syk kinase in Fc gamma receptor (Fc gamma R) IIA-mediated phagocytosis was examined with two forms of antisense oligodeoxynucleotides (ODNs) designed to hybridize to human Syk mRNA. Monocytes were incubated with linear and stem-loop antisense ODNs targeted to Syk mRNA. When complexed with cationic liposomes, stem-loop Syk antisense ODN with phosphorothioate modification exhibited stability in fetal bovine and human serum. The stem-loop Syk antisense ODN at a concentration of 0.2 microM inhibited Fc gamma RIIA-mediated phagocytosis by 90% and completely eliminated Syk mRNA and protein in monocytes, whereas scrambled-control ODNs had no effect. The Syk antisense ODNs did not change beta-actin mRNA levels and Fc gamma RII cell-surface expression. In addition, stem-loop Syk antisense ODN inhibited Fc gamma RI and Fc gamma RIIIA-mediated phagocytosis. These data indicate the efficacy of stem-loop Syk antisense ODN for targeting and degrading Syk mRNA and protein and the importance of Syk kinase in Fc gamma receptor-mediated phagocytosis. Immunoblotting assay demonstrated that Fc gamma RII tyrosine phosphorylation after Fc gamma RII cross-linking did not change in the absence of Syk protein. These results indicate that Syk kinase is required for Fc gamma RIIA-mediated phagocytic signaling and that Fc gamma RII cross-linking leads to tyrosine phosphorylation of Fc gamma RII independent of Syk kinase.
authors.affiliation: Hematology and Oncology Division, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
authors.forename: M
authors.initials: M
authors.lastname: Matsuda
authors.forename: J G
authors.initials: JG
authors.lastname: Park
authors.forename: D C
authors.initials: DC
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Hunter
authors.forename: P
authors.initials: P
authors.lastname: Chien
authors.forename: A D
authors.initials: AD
authors.lastname: Schreiber
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D004792:Enzyme Precursors / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000502:physiology; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009000:Monocytes / Q000187:drug effects / Q000276:immunology / Q000502:physiology; D009690:Nucleic Acid Conformation; D016376:Oligonucleotides, Antisense / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology*; D010587:Phagocytosis / Q000276:immunology / Q000502:physiology; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017452:Receptors, IgG / Q000502:physiology*; D000072377:Syk Kinase; D014443:Tyrosine / Q000378:metabolism
chemical_list: D004792:Enzyme Precursors; D047908:Intracellular Signaling Peptides and Proteins; D016376:Oligonucleotides, Antisense; D012333:RNA, Messenger; D017452:Receptors, IgG; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase