Roles of Enterococcus in carcinogenesis and inflammation

• Project/Area Number: 18K07904
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 53010:Gastroenterology-related
• Research Institution: Kanazawa University
• Principal Investigator: IIDA Noriho 金沢大学, 附属病院, 助教 (40705604)
• Co-Investigator(Kenkyū-buntansha): 北村 和哉 金沢大学, 附属病院, 助教 (00579633) ; 藤永 由佳子 金沢大学, 医学系, 教授 (60252954)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Project Status: Completed (Fiscal Year 2021)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000); Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2018: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: 腸内細菌 / 腸内細菌叢 / 肝癌 / 腸炎

Outline of Final Research Achievements

Because Enterococci are opportunistic pathogens, colonization and proliferation of Enterococci should be regulated. In mouse liver carcinogenesis model, transplantation of microbiota derived from healthy donors suppressed proliferation of E. faecalis in the gut, resulting in decrease of the number of liver tumors. In mouse colitis model, microbiota of healthy donors suppressed proliferation of E. faecalis, but prednisolone enabled colonization of E. faecium due to decrease of mucin and antimicrobial peptide. Thus, factors regulating Enterococci were clarified in this study.

Academic Significance and Societal Importance of the Research Achievements

腸内細菌叢が人の健康と疾患に大きな役割を持つことが解明されてきた。しかし100種類以上かつ100兆個近い細菌を含む腸内細菌叢は複雑であり、腸内細菌叢を制御する治療手段は未だ十分に発達していない。細菌叢の構成はpH、酸素含有量、栄養素含有量、抗菌物質の存在、ホストの免疫など腸内環境に制御され決定される。そのため、それらの因子を決定する細菌と細菌の相互作用、細菌とホスト細胞の相互作用の解明が求められているが十分には解明されていない。