Involvement of protein kinase D in uridine diphosphate-induced microglial macropinocytosis and phagocytosis

Ayumi Uesugi, Ayako Kataoka, Hidetoshi Saitoh, Yui Koga, Tsuda Makoto, Bernard Robaye, Jean Marie Boeynaems, Kazuhide Inoue

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

The clearance of tissue debris by microglia is a crucial component of maintaining brain homeostasis. Microglia continuously survey the brain parenchyma and utilize extracellular nucleotides to trigger the initiation of their dynamic responses. Extracellular uridine diphosphate (UDP), which leaks or is released from damaged neurons, has been reported to stimulate the phagocytotic activity of microglia through P2Y6 receptor activation. However, the intracellular mechanisms underlying microglial P2Y6 receptor signals have not been identified. In this study, we demonstrated that UDP stimulation induced immediate and long-lasting dynamic movements in the cell membrane. After 60 min of UDP stimulation, there was an upregulation in the number of large vacuoles formed in the cell that incorporate extracellular fluorescent-labeled dextran, which indicates microglial macropinocytosis. In addition, UDP-induced vacuole formation and continuous membrane motility were suppressed by the protein kinase D (PKD) inhibitors, Gö6976 and CID755673, unlike Gö6983, which is far less sensitive to PKD. The inhibition of PKD also reduced UDP-induced incorporation of fluorescent-labeled dextran and soluble β-amyloid and phagocytosis of microspheres. UDP induced rapid phosphorylation and membrane translocation of PKD, which was abrogated by the inhibition of protein kinase C (PKC) with Gö6983. However, Gö6983 failed to suppress UDP-induced incorporation of microspheres. Finally, we found that inhibition of PKD by CID755673 significantly suppressed UDP-induced engulfment of IgG-opsonized microspheres. These data suggest that a PKC-independent function of PKD regulates UDP-induced membrane movement and contributes to the increased uptake of extracellular fluid and microspheres in microglia.

Original languageEnglish
Pages (from-to)1094-1105
Number of pages12
JournalGLIA
Volume60
Issue number7
DOIs
Publication statusPublished - Jul 1 2012

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Uridine Diphosphate
Phagocytosis
Microglia
Microspheres
Vacuoles
Dextrans
Protein Kinase C
protein kinase D
Membranes
Extracellular Fluid
Brain
Protein Kinase Inhibitors
Amyloid
Membrane Proteins
Homeostasis
Up-Regulation
Nucleotides
Immunoglobulin G
Phosphorylation
Cell Membrane

All Science Journal Classification (ASJC) codes

  • Cellular and Molecular Neuroscience
  • Neurology

Cite this

Involvement of protein kinase D in uridine diphosphate-induced microglial macropinocytosis and phagocytosis. / Uesugi, Ayumi; Kataoka, Ayako; Saitoh, Hidetoshi; Koga, Yui; Makoto, Tsuda; Robaye, Bernard; Boeynaems, Jean Marie; Inoue, Kazuhide.

In: GLIA, Vol. 60, No. 7, 01.07.2012, p. 1094-1105.

Research output: Contribution to journalArticle

Uesugi, Ayumi ; Kataoka, Ayako ; Saitoh, Hidetoshi ; Koga, Yui ; Makoto, Tsuda ; Robaye, Bernard ; Boeynaems, Jean Marie ; Inoue, Kazuhide. / Involvement of protein kinase D in uridine diphosphate-induced microglial macropinocytosis and phagocytosis. In: GLIA. 2012 ; Vol. 60, No. 7. pp. 1094-1105.
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