Data_Sheet_1_Krill oil supplementation in vivo promotes increased fuel metabolism and protein synthesis in cultured human skeletal muscle cells.docx

IntroductionKrill oil is a dietary supplement derived from Antarctic krill; a small crustacean found in the ocean. Krill oil is a rich source of omega-3 fatty acids, specifically eicosapentaenoic acid and docosahexaenoic acid, as well as the antioxidant astaxanthin. The aim of this study was to investigate the effects of krill oil supplementation, compared to placebo oil (high oleic sunflower oil added astaxanthin), in vivo on energy metabolism and substrate turnover in human skeletal muscle cells.
MethodsSkeletal muscle cells (myotubes) were obtained before and after a 7-week krill oil or placebo oil intervention, and glucose and oleic acid metabolism and leucine accumulation, as well as effects of different stimuli in vitro, were studied in the myotubes. The functional data were combined with proteomic and transcriptomic analyses.
ResultsIn vivo intervention with krill oil increased oleic acid oxidation and leucine accumulation in skeletal muscle cells, however no effects were observed on glucose metabolism. The krill oil-intervention-induced increase in oleic acid oxidation correlated negatively with changes in serum low-density lipoprotein (LDL) concentration. In addition, myotubes were also exposed to krill oil in vitro. The in vitro study revealed that 24 h of krill oil treatment increased both glucose and oleic acid metabolism in myotubes, enhancing energy substrate utilization. Transcriptomic analysis comparing myotubes obtained before and after krill oil supplementation identified differentially expressed genes associated with e.g., glycolysis/gluconeogenesis, metabolic pathways and calcium signaling pathway, while proteomic analysis demonstrated upregulation of e.g., LDL-receptor in myotubes obtained after the krill oil intervention.
ConclusionThese findings suggest that krill oil intervention promotes increased fuel metabolism and protein synthesis in human skeletal muscle cells, with potential implications for metabolic health.

引言
磷虾油（krill oil）是一种源自南极磷虾（Antarctic krill）的膳食补充剂，南极磷虾是栖息于海洋的小型甲壳类动物。磷虾油富含ω-3脂肪酸，具体包括二十碳五烯酸（eicosapentaenoic acid）与二十二碳六烯酸（docosahexaenoic acid），同时含有抗氧化剂虾青素（astaxanthin）。本研究旨在探究相较于添加虾青素的高油酸葵花籽油安慰剂，补充磷虾油对人体骨骼肌细胞体内能量代谢及底物周转的影响。

方法
研究团队分别于7周磷虾油或安慰剂干预前后采集骨骼肌细胞（肌管，myotubes），体外检测肌管的葡萄糖代谢、油酸代谢及亮氨酸积累情况，同时探究不同刺激因素的干预效果。随后将功能学实验数据与蛋白质组学（proteomic）、转录组学（transcriptomic）分析结果进行整合。

结果
体内磷虾油干预可提升骨骼肌细胞的油酸氧化水平与亮氨酸积累量，但对葡萄糖代谢无显著影响。磷虾油干预诱导的油酸氧化升高与血清低密度脂蛋白（low-density lipoprotein, LDL）浓度变化呈负相关。此外，本研究还对肌管开展了体外磷虾油处理实验：体外实验结果显示，24小时磷虾油处理可增强肌管的葡萄糖与油酸代谢能力，提升能量底物利用效率。对比干预前后采集的肌管进行转录组学分析发现，差异表达基因富集于糖酵解/糖异生、代谢通路及钙信号通路等生物学过程；蛋白质组学分析则显示，磷虾油干预后采集的肌管中低密度脂蛋白受体（LDL-receptor）等蛋白表达上调。

结论
本研究结果表明，磷虾油干预可促进人体骨骼肌细胞的燃料代谢与蛋白质合成，对代谢健康具有潜在积极意义。