Exploration of the role of Keap1-Nrf2 signaling pathway in renal fibrosis

Research Project

Project/Area Number	19K08685
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 53040:Nephrology-related
Research Institution	Jichi Medical University
Principal Investigator	Nagata Daisuke 自治医科大学, 医学部, 教授 (40393194)
Co-Investigator(Kenkyū-buntansha)	前嶋明人自治医科大学, 医学部, 准教授 (70431707)
Project Period (FY)	2019-04-01 – 2022-03-31
Project Status	Completed (Fiscal Year 2021)
Budget Amount *help	¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000) Fiscal Year 2021: ¥390,000 (Direct Cost: ¥300,000、Indirect Cost: ¥90,000) Fiscal Year 2020: ¥520,000 (Direct Cost: ¥400,000、Indirect Cost: ¥120,000) Fiscal Year 2019: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Keywords	KEAP1-Nrf2系 / 腎間質線維化 / バルドキソロンメチル / Nrf2活性化 / 片側尿細管結紮モデル / Nrf2-KEAP1 / 血管内皮細胞 / Bardoxolone methyl / 腎尿細管 / 傍糸球体毛細血管 / Nrf2 / Keap1
Outline of Research at the Start	腎臓の血管内皮Nrf2活性化が、抗線維化因子の産生を増加させるか確かめるため、2つの検討をする。1)CDDO-Me刺激がNrf2を介して抗線維化因子の発現を増加させるか確認し、その因子を同定する。2)血管内皮特異的Nrf2 knock out マウスを作成し、腎虚血再灌流障害モデル、片側尿管結紮モデルにより間質線維化が増強するか検討し、in vivoにおける血管内皮Nrf2の重要性を明らかにする。
Outline of Final Research Achievements	Two-week unilateral tubular ligation (UUO) was performed on C57BL / 6 mice, and C-28 methyl ester of 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO-Me), which has the effect of activating Nrf2, was administered. The fibrotic area was reduced when fibrosis was evaluated by Sirius red staining compared with the control. In this study, we generated conditional knock-out mice lacking Nrf2 in a tubular and endothelium-specific manner (Pax8-Cre / flox-Nrf2 and Tie2-Cre / flox-Nrf2, respectively). When a UUO model was created, the density of peritubular capillaries was not different from that of the control flox-Nrf2 mouse. However, Pax8-Cre / flox-Nrf2 mice significantly increased interstitial fibrosis compared to Tie2-Cre / flox-Nrf2 and flox-Nrf2 mice. When TGF-b and collagen I were evaluated by real-time PCR, these expressions increased. These results suggest that renal tubular Nrf2 activation could suppress renal interstitial fibrosis.
Academic Significance and Societal Importance of the Research Achievements	バルドキソロンメチルによりNrf2が活性化されると、腎間質線維化は抑制されることは以前の研究で明らかにされていたが、その機序の詳細や、腎臓のどの部位のNrf2の活性化が重要なのかは長期間不明のままであった。今回の研究で、それが尿細管におけるNrf2の活性がが重要であることが明確に示された。