| Project/Area Number |
14370198
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Respiratory organ internal medicine
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| Research Institution | Sapporo Medical University |
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Principal Investigator |
KUROKI Yoshto Sapporo Medical University, School of Medicine, Professor, 医学部, 教授 (70161784)
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| Co-Investigator(Kenkyū-buntansha) |
IWAKI Daisuke Sapporo Medical University, School of Medicine, Research Associate, 医学部, 助手 (10315492)
SANO Hitomi Sapporo Medical University, School of Medicine, Associate Professor, 医学部, 助教授 (80295344)
TAKAHASHI Hiroki Sapporo Medical University, School of Medicine, Associate Professor, 医学部, 助教授 (60231396)
TAKAHASHI Toru Sapporo Medical University, School of Medicine, Research Associate, 医学部, 助手 (40347159)
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| Project Period (FY) |
2002 – 2003
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| Keywords | pulmonary surfactant / SP-A / SP-D / Toll-like receptor / scavenger receptor A / mannose receptor / alveolar macrophage / zymosan |
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| Research Abstract |
The purpose of this project was to investigate the molecular mechanisms of hg and recognition by lung collectins, SP-A and SP-D, and Toll-like receptor(TLR) and of the colletin-mediated and-inflammatory function and modulation of macrophage functions.
1.A soluble form of recombinant TLR2 consisting of Met1-Arg587(sTLR2) was generated and expressed by baculovirus-insect cell expression system. sTLR2 was found to bind directly to peptidoglycn derived from Staphylococcus aureus and zymosan.
2.SP-A bound to sTLR2 and the binding of SP-A to sTLR2 significantly attenuated the binding of sTLR2 to peptidoglycan and zymosan.
3.SP-D as well as SP-A interacted with sTLR2.
4.SP-A bound to Streptococcus pneumoniae and Mycobacterium avium in a manner dependent upon the SP-A concentrations and Ca2+. SP-A augemented the phagocytosis of S.pneumoniae and M.avium by its direct interaction with alveolar macrophages independent of its binding to the bacteria. In addition, SP-A stimualted the scavenger receptor A-mediated phagocytosis of S.pneumoniae and the mannose receptor-mediated phagocytosis of M.avium. Although SP-D augmented the M.avium phagocytosis, this protein did not enhance the phagocytosis of S.pneumoniae, indicating the different mechanisms of the bacterial phagocytosis stimulated by lung collectins.
5.A soluble form of recombinant TLR4 extracellular domain(sTLR4) and recombinant MD-2 were generated and expressed in bacluovirus-insect cell expression system. MD-2 was demonstrated to bind directly to sTLR4 but not to sTLR2. A complex of sTLR4 and MD-2 was able to bind to LPS covalenrly linked to sepharose beads although sTLR4 alone failed to bind LPS.
6.These results suggest that lung collectins, SP-A and SP-D, sTLR2 and sTLR4 can function as mudulators for TLR-mediated inflammation and for macrophage phagocytosis.
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