School of Food Science and Technology, Dalian Polytechnic University, Qinggongyuan1, Ganjingzi District, Dalian 116034, Liaoning, China.
Food Funct. 2020 Jul 22;11(7):6487-6495. doi: 10.1039/d0fo01350a.
Endogenous nanoparticles produced during food processing have received considerable attention due to their unique physicochemical properties and potential safety risks. However, the bio-impact of endogenous nanoparticles on cell metabolism has not been fully studied. In this work, the effects of carbon dots (CDs) derived from the Maillard reaction of glucose and lysine on the cellular substance and energy metabolism were assessed using HepG2 cells as a model. When the HepG2 cells were incubated with 10.0 mg mL-1 of CDs, the mitochondrial membrane potential decreased significantly and the mitochondrial function was affected. The extracellular acidification rate and oxygen consumption rate were decreased in comparison to normal cells without CDs. The CDs blocked the glycolysis pathway by reducing the activities of key enzymes including phosphofructokinase and pyruvate kinase. The energy supply pathway of HepG2 cells changed from glycolysis to TCA cycle, but the increase of the TCA cycle flux could not meet the requirements for restoring cell proliferation. The increase of the compensatory flux in the TCA cycle may be the result of up-regulation of the metabolism of glucogenic amino acids and ketogenic amino acids, while lipid metabolism did not seem to be affected in this process.
内源性纳米颗粒是在食品加工过程中产生的，由于其独特的物理化学性质和潜在的安全风险而受到广泛关注。然而，内源性纳米颗粒对细胞代谢的生物影响尚未得到充分研究。在这项工作中，以 HepG2 细胞为模型，评估了葡萄糖和赖氨酸美拉德反应生成的碳点 (CDs) 对细胞物质和能量代谢的影响。当 HepG2 细胞与 10.0 mg mL-1 的 CDs 孵育时，线粒体膜电位显著降低，线粒体功能受到影响。与没有 CDs 的正常细胞相比，细胞外酸化率和耗氧率降低。CDs 通过降低磷酸果糖激酶和丙酮酸激酶等关键酶的活性来阻断糖酵解途径。HepG2 细胞的能量供应途径从糖酵解转变为 TCA 循环，但 TCA 循环通量的增加不足以满足恢复细胞增殖的要求。TCA 循环中补偿通量的增加可能是糖质氨基酸和生酮氨基酸代谢上调的结果，而在这个过程中似乎没有影响脂质代谢。
