2005 Fiscal Year Final Research Report Summary
Research of the molecular mechanism of the phagocytosis in innate immunity
| Project/Area Number |
16590229
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General medical chemistry
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| Research Institution | Kobe University |
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Principal Investigator |
TOHYAMA Yumi Kobe University, Graduate school of Medicine, Associate Professor, 大学院・医学系研究科, 助教授 (70362770)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMURA Hirohei Kobe University, Graduate school of Medicine, Professor, 大学院・医学系研究科, 教授 (90030882)
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| Project Period (FY) |
2004 – 2005
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| Keywords | phagocytosis / tyrosine kinase / Syk / complement / cytoskeleton / RhoA / infection / innate immunity |
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| Research Abstract |
Phagocytosis is a central event in the innate immune responses that are triggered by the association between ligands on the surface of pathogens and receptors on the membrane of phagocytes. A protein-tyrosine kinase, Syk plays a central role in Fcγ-mediated phagocytosis in the adaptive immune system. Here we show that Syk is also essential for the process of phagocytosis via complement activation. Phagocytosis assay was performed using macrophage-like differentiated HL60 cells as phagocytes and C3bi-opsonized zymosan as a pathogen. Syk was promptly activated and accumulation of Syk around the nascent phagosomes was detected. Dominant-negative Syk(DN-Syk) or Syk-siRNA was transferred to HL60 cells. Quantitative analysis using flow cytometry showed that transfer of either DN-Syk or Syk-siRNA resulted in the inhibition of phagocytosis. Quenching assay of fluorescence-labeled-zymosan revealed that Syk is required for engulfment of C3bi-bound zymosan but not for attachment of C3bi-zymosan to complement receptor 3 (CR3).
To clarify the molecular mechanism how Syk affects the process of phagosome formation and its engulfment, the change of actin dynamics and the activation of RhoA were investigated. At the early stage of phagocytosis, there was a marked accumulation of actin around phagosomes, which was followed by rapid dissociation. On the other hand, transfer of DN-Syk or Syk-siRNA led to attenuated accumulation of actin around the nascent phagosomes. In addition, RhoA was clearly activated in HL60 cells but the activation was decreased in both mutant cells. These results indicate that Syk plays an essential role in complement-mediated phagocytosis in the process of phagosome engulfment in related to actin dynamics.
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Research Products
(10 results)
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[Journal Article] Protein-tyrosine kinase, Syk is required for pathogen engulfment in complement-mediated phagocytosis.2006
Author(s)
Shi, Y., Tohyama, Y., Kadono, T., He, J., Miah, S.M.S., Hazama, R., Tanaka, C., Tohyama, K., Yamamura, H.
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Journal Title
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Effects of peripheral cannabinoid receptor ligands on motility and polarization in neutrophil-like HL60 cells and human neutrophils.2006
Author(s)
Kurihara, R., Tohyama.Y., Matsusaka, S., Naruse, H., Kinoshita, E., Tsujioka, T., Katsumata, Y., Yamamura, H.
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Journal Title
J.Biol.Chem. 281
Pages: 12908-12918
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Protein-tyrosine kinase, Syk, is required for CXCL12-induced polarization of B cells.2005
Author(s)
Matsusaka, S., Tohyama.Y., He, J., Shi, Y., Hazama, R., Kadono, T., Kurihara, R., Tohyama, K., Yamamura, H.
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Journal Title
Biochem.Biophys.Res.Commun. 328
Pages: 1163-1169
Description
「研究成果報告書概要(欧文)」より
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[Journal Article] Lysosome is a primary organelle in B cell receptor-mediated apoptosis : an indispensable role of Syk in lysosomal function.2005
Author(s)
He, J., Tohyama Y., Yamamoto, K., Kobayashi, M., Shi, Y., Takano, T., Noda, C., Tohyama, K., Yamamura, H.
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Journal Title
Genes Cells 10
Pages: 23-35
Description
「研究成果報告書概要(欧文)」より
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