Abrogation of the Fc gamma receptor IIA-mediated phagocytic signal by stem-loop Syk antisense oligonucleotides

Mol Biol Cell. 1996 Jul;7(7):1095-106. doi: 10.1091/mbc.7.7.1095.

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Base Sequence
  • Cattle
  • Enzyme Precursors / antagonists & inhibitors*
  • Enzyme Precursors / genetics*
  • Enzyme Precursors / physiology
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Molecular Sequence Data
  • Monocytes / drug effects
  • Monocytes / immunology
  • Monocytes / physiology
  • Nucleic Acid Conformation
  • Oligonucleotides, Antisense / chemistry
  • Oligonucleotides, Antisense / genetics
  • Oligonucleotides, Antisense / pharmacology*
  • Phagocytosis / immunology
  • Phagocytosis / physiology
  • Phosphorylation
  • Protein-Tyrosine Kinases / antagonists & inhibitors*
  • Protein-Tyrosine Kinases / genetics*
  • Protein-Tyrosine Kinases / physiology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptors, IgG / physiology*
  • Syk Kinase
  • Tyrosine / metabolism

Substances

  • Enzyme Precursors
  • Intracellular Signaling Peptides and Proteins
  • Oligonucleotides, Antisense
  • RNA, Messenger
  • Receptors, IgG
  • Tyrosine
  • Protein-Tyrosine Kinases
  • SYK protein, human
  • Syk Kinase