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    α-酮戊二酸代谢紊乱介导棕榈酸(PA)诱导斑马鱼肝脏脂肪异常沉积的机制研究

    MECHANISM STUDY OF Α-KETOGLUTARATE METABOLISM DISTURBANCE MEDIATES PALMITIC ACID (PA)-INDUCED ABNORMAL HEPATIC LIPID DEPOSITION IN ZEBRAFISH (DANIO RERIO)

    • 摘要: 为了探究α-酮戊二酸(AKG)调控斑马鱼脂肪代谢的具体分子机制, 本研究发现, 在体摄食棕榈油饲料或离体棕榈酸(PA)孵育会降低斑马鱼肝脏或肝细胞内的AKG代谢相关基因表达, 减少AKG含量。进一步实验证明, 外源补充AKG可缓解PA诱导的AKG代谢紊乱, 同时影响过氧化物酶体增殖物激活受体(PPARs)表达, 进而促进脂肪酸β-氧化、抑制脂肪合成, 减轻脂质沉积。而使用谷氨酸脱氢酶抑制剂(R162)抑制AKG内源合成则会抑制脂肪酸β-氧化、促进脂肪合成, 诱导肝细胞脂质沉积。此外, 进一步研究发现PA诱导的脂肪异常沉积与雷帕霉素靶蛋白复合物1(mTORC1)信号通路的异常激活有关, 而外源补充AKG能有效抑制PA诱导的mTORC1信号通路激活。综上所述, 我们的研究表明摄食棕榈油饲料可能通过诱导AKG代谢紊乱, 激活mTORC1信号通路, 影响PPARs表达, 进而抑制脂肪酸β-氧化、促进脂肪合成, 导致斑马鱼肝脏脂质沉积。上述研究为理解AKG在鱼类脂代谢调控中的作用提供了理论基础, 同时为棕榈油饲料的高效利用提供了潜在调控靶点。

       

      Abstract: To elucidate the specific molecular mechanisms by which α-ketoglutarate (AKG) regulates fat metabolism in zebrafish, this study demonstrated that oral administration of palm oil feed or ex vivo incubation with palmitic acid (PA) reduced the expression of AKG-metabolism-related genes in zebrafish livers or hepatocytes, thereby decreasing AKG levels. This study revealed that feeding palm oil in vivo or incubation with exogenous palmitic acid (PA) reduced the expression of AKG metabolism-related genes in zebrafish livers or hepatocytes, thereby decreasing AKG levels. Further experiments demonstrated that exogenous supplementation of AKG alleviates PA-induced AKG metabolic disturbances while modulating the expression of peroxisome proliferator-activated receptors (PPARs), thereby promoting fatty acid β-oxidation, inhibiting lipogenesis, and reducing lipid deposition. Conversely, inhibition of endogenous AKG synthesis using glutamate dehydrogenase inhibitor R162suppressed fatty acid β-oxidation, enhanced lipogenesis, and induced hepatic lipid deposition. Additionally, PA-induced abnormal lipid deposition was associated with aberrant activation of the mTORC1signaling pathway, and exogenous AKG supplementation effectively inhibited this activation. In conclusion, feeding palm oil may induce AKG metabolic disturbances, activate the mTORC1signaling pathway, alter PPARs expression, subsequently inhibit fatty acid β-oxidation, promote lipogenesis, and ultimately lead to hepatic lipid deposition in zebrafish. These findings provides a theoretical foundation for understanding how AKGregulateslipid metabolism in fish and identify potential regulatory targets for the efficient utilization of palm oil feeds.

       

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