Protective roles of BLT2 receptor in epithelial barrier function

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K08316
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Pathological medical chemistry
• Research Institution: Juntendo University
• Principal Investigator: Saeki Kazuko 順天堂大学, 医学部, 准教授 (00553273)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 上皮細胞 / バリア機能 / 生理活性脂質 / 細胞間接着

Outline of Final Research Achievements

To investigate the roles of BLT2 in epithelial barrier function, we used atopic dermatitis model and acute lung injury model.
Atopic dermatitis model: BLT2-deficient mice exhibited higher transepidermal water loss and were more sensitive to epicutaneous sensitization. Our data using BLT2-overexpressing cells and primary keratinocytes showed that 12-HHT/BLT2 enhances epithelial barrier function by increasing CLDN4 expression via the Gαi protein-p38 MAPK pathway. Acute lung injury model: Intratracheal injection of PLY caused lethal acute lung injury in BLT2-deficient mice, with evident vascular leakage and bronchoconstriction. Large amounts of cysteinyl leukotrienes were detected in PLY-treated lungs. PLY-dependent vascular leakage, bronchoconstriction, and death were markedly ameliorated by treatment with a CysLT1 antagonist. Treatment of mice with NSAIDs inhibited the production of 12-HHT and increased the sensitivity toward PLY, which was also ameliorated by the CysLT1 antagonist.

Free Research Field

脂質生化学

Academic Significance and Societal Importance of the Research Achievements

非ステロイド性抗炎症薬（NSAIDs）は世界中で広く使用されているものの、効能や副作用の発現メカニズムについては不明な点が多い。NSAIDsがシクロオキシゲナーゼ（COX）を阻害することで多数の生理活性脂質の産生が同時に抑制される為である。本研究において、BLT2欠損マウスで観察されたPLY依存性の個体死が、野性型マウスへのNSAIDs投与でも観察されたことから、NSAIDsが肺炎致死の増悪因子となることを示した。更にこの個体死がCysLT1受容体拮抗薬の前投与で回避できたことから、気管支喘息治療薬として認可されているCysLT1受容体拮抗薬が肺炎球菌による肺炎治療へ応用できる可能性を示した。