Molecular mechanism and clinical implications of Sigle-9 induced cell death of activated neutrophils.

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K09661
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Pediatrics
• Research Institution: Kyoto Prefectural University of Medicine
• Principal Investigator: Kano Gen 京都府立医科大学, 医学(系)研究科(研究院), 特任助教 (50725306)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: Siglec / Cell death / neutrophil / eosinophil

Outline of Final Research Achievements

Upon Siglec-8/IL-5 co-stimulation induced eosinophil cell death, mitochondrial membrane potential change and mitochondrial ROS production, assessed by flow cytometry, were not significant, suggesting no major role of mitochondria.
Phosphorylation of NOX2 activating subunits, p40phox and p47phox, were detected with Western blotting and phosphoflow, although the magnitudes were substantially smaller than those observed in PMA or ETosis stimulation. Surface expression of gp91phox, also measured by flow cytometry, was unchanged even when increased intracellular ROS was observed, contrary to the significant upregulation after PMA or ETosis stimulation.

Free Research Field

免疫学

Academic Significance and Societal Importance of the Research Achievements

上記成果より、NOX2が細胞表面に露出しない形での特殊な活性化が、細胞内優位のROS増多に関与することが示唆された。一方好中球について、他の研究グループより同様に、活性化サイトカインであるGM-CSF存在下で、Siglec-9刺激による細胞死増強が報告されているものの、今回 Siglec-8と同様にモノクローナル抗体を用いたSiglec-9刺激を行ったところ、その細胞死誘導効果はSiglec-8によるものほど顕著ではなかった。好中球における NOX2は元来、好酸球よりも細胞内優位のROS産生をしていることが知られており、細胞外ROSのダイナミックな調節が好酸球の特異的機能であることが示された。