| Project/Area Number |
23K06477
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 49030:Experimental pathology-related
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| Research Institution | Tohoku University |
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Principal Investigator |
齋木 由利子 東北大学, 医学系研究科, 准教授 (80311223)
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| Project Period (FY) |
2023-04-01 – 2026-03-31
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| Project Status |
Granted (Fiscal Year 2023)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2025: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2024: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2023: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | Dusp6 / NAFLD / Cyp4A / 非アルコール性脂肪肝 |
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| Outline of Research at the Start |
Dusp6ノックアウトマウスの肝細胞では、遊離脂肪酸のオメガ酸化を触媒するCYP4A遺伝子群の発現が著明に低下していることがわかった。CYP4Aファミリーの１つであるCyp4A14のKOマウスでは、高脂肪食投与によるNAFLDの発症が強く抑制されることが報告されている。DUSP6はERK特異的な脱リン酸化酵素で、MAPK経路の過剰活性化を防ぐ役割を担っていると考えられているが、CYP4ファミリーとの関係は今まで報告がない。本研究では、肝臓の脂肪代謝におけるDUSP6-CYP4経路の役割を明らかにし、NAFLDの新しい治療ターゲットの同定をめざす。
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| Outline of Annual Research Achievements |
Dual specificity phosphatase 6 (DUSP6) is a specific phosphatase for mitogen-activated protein kinase (MAPK). In this study, we used a high-fat diet (HFD)-induced murine non-alcoholic fatty liver disease (NAFLD) model to investigate the role of DUSP6 in this disease. Wild-type (WT) and Dusp6-haploinsufficient (HI) mice developed severe obesity and liver pathology consistent with NAFLD when exposed to HFD. In contrast, Dusp6-knockout (KO) mice completely eliminated these phenotypes. Furthermore, primary hepatocytes isolated from WT mice exposed to palmitic and oleic acids exhibited abundant intracellular lipid accumulation, while hepatocytes from Dusp6-KO mice showed minimal lipid accumulation. Transcriptome analysis revealed significant downregulation of genes encoding cytochrome P450 4A (CYP4A), known to promote ω-hydroxylation of fatty acids and hepatic steatosis, in Dusp6-KO hepatocytes compared with WT hepatocytes. Diminished CYP4A expression was observed in the liver of Dusp6-KO mice compared to WT and Dusp6-HI mice. Knockdown of DUSP6 in HepG2, a human liver-linage cell line, also promoted a reduction of lipid accumulation, downregulation of CYP4A, and upregulation of phosphorylated/activated MAPK. Furthermore, inhibition of MAPK activity promoted lipid accumulation in DUSP6-knockdown HepG2 cells without affecting CYP4A expression, indicating that CYP4A expression is independent of MAPK activation. These findings highlight the significant role of DUSP6 in HFD-induced steatohepatitis through two distinct pathways involving CYP4A and MAPK.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
仮説どおりにおおむね、順調に実験がすすんだ。
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| Strategy for Future Research Activity |
Dusp6が、どのようにCyp4Aの発現を制御しているか、分子生物学的に明らかにしていく。
手法としては、肝細胞株におけるDusp6のノックダウン、過剰発現を行い、下流の遺伝子の模索をすすめる。
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