Karvinen Sira, Fachada Vasco, Sahinaho Ulla-Maria, Pekkala Satu, Lautaoja Juulia H, Mäntyselkä Sakari, Permi Perttu, Hulmi Juha J, Silvennoinen Mika, Kainulainen Heikki
NeuroMuscular Research Center, Faculty of Sport and Health Sciences, University of Jyväskylä, FI-40014 Jyväskylä, Finland.
Department of Biological and Environmental Science, University of Jyväskylä, FI-40014 Jyväskylä, Finland.
Metabolites. 2022 Apr 5;12(4):328. doi: 10.3390/metabo12040328.
Impaired lipid metabolism is a common risk factor underlying several metabolic diseases such as metabolic syndrome and type 2 diabetes. Branched-chain amino acids (BCAAs) that include valine, leucine and isoleucine have been proven to share a role in lipid metabolism and hence in maintaining metabolic health. We have previously introduced a hypothesis suggesting that BCAA degradation mechanistically connects to lipid oxidation and storage in skeletal muscle. To test our hypothesis, the present study examined the effects of BCAA deprivation and supplementation on lipid oxidation, lipogenesis and lipid droplet characteristics in murine C2C12 myotubes. In addition, the role of myotube contractions on cell metabolism was studied by utilizing in vitro skeletal-muscle-specific exercise-like electrical pulse stimulation (EPS). Our results showed that the deprivation of BCAAs decreased both lipid oxidation and lipogenesis in C2C12 myotubes. BCAA deprivation further diminished the number of lipid droplets in the EPS-treated myotubes. EPS decreased lipid oxidation especially when combined with high BCAA supplementation. Similar to BCAA deprivation, high BCAA supplementation also decreased lipid oxidation. The present results highlight the role of an adequate level of BCAAs in healthy lipid metabolism.
脂质代谢受损是多种代谢性疾病（如代谢综合征和2型糖尿病）的常见潜在风险因素。包括缬氨酸、亮氨酸和异亮氨酸在内的支链氨基酸（BCAAs）已被证明在脂质代谢中发挥作用，从而有助于维持代谢健康。我们之前提出了一个假说，认为BCAA降解在机制上与骨骼肌中的脂质氧化和储存相关。为了验证我们的假说，本研究考察了BCAA缺失和补充对小鼠C2C12肌管中脂质氧化、脂肪生成和脂滴特征的影响。此外，通过利用体外骨骼肌特异性的类似运动的电脉冲刺激（EPS），研究了肌管收缩对细胞代谢的作用。我们的结果表明，BCAAs的缺失降低了C2C12肌管中的脂质氧化和脂肪生成。BCAA缺失进一步减少了经EPS处理的肌管中的脂滴数量。EPS降低了脂质氧化，尤其是在与高剂量BCAA补充剂联合使用时。与BCAA缺失相似，高剂量BCAA补充剂也降低了脂质氧化。目前的结果突出了适当水平的BCAAs在健康脂质代谢中的作用。
