Department of Pharmacology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Department of Pharmacology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan; Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan.
Eur J Pharmacol. 2024 Dec 5;984:177070. doi: 10.1016/j.ejphar.2024.177070. Epub 2024 Oct 21.
Methylglyoxal (MGO) is a potent precursor of glycative stress that leads to oxidative stress and muscle atrophy in diabetes. Spatheliachromen (FPATM-20), derived from Ficus pumila var. awkeotsang, exhibited potential antioxidant activity.
This study aimed to evaluate the potential impact and underlying mechanisms of FPATM-20 on MGO-induced myotube atrophy and mitochondrial dysfunction in mouse skeletal C2C12 myotubes.
Atrophic and antioxidant factors were evaluated using immunofluorescence, enzyme-linked immunosorbent assay, and western blotting. Mitochondrial function was assessed using the ATP assay and Seahorse Cell Mito Stress Test. The glycogen content was determined using periodic acid-Schiff staining. Molecular docking was performed to determine the interaction between FPATM-20 and Keap1.
In myotubes treated with MGO, FPATM-20 activated the Nrf2 pathway, reduced ROS levels, enhanced antioxidant defense, and increased glycogen content. FPATM-20 improved myotube viability and size, upregulated myosin heavy chain (MyHC) expression, modulated ubiquitin-proteasome molecules (nuclear FoxO3a, atrogin-1, MuRF-1, and p62/SQSTM1), and inhibited apoptosis (Bax/Bcl-2 ratio and cleaved caspase 3). Moreover, FPATM-20 restored mitochondrial function, including mitochondrial membrane potential, mitochondrial oxygen consumption rate, and mitochondrial biogenesis pathway (nuclear PGC-1α/TFAM/FNDC5). The inhibition of Nrf2 with ML385 reversed the effects of FPATM-20 on MGO. Furthermore, molecular docking confirmed the binding of FPATM-20 to Keap1, a suppressor of Nrf2, showing the crucial role of Nrf2 in protective effects.
FPATM-20 protects myotubes from MGO toxicity by activating the Nrf2 antioxidant defense, reducing protein degradation and apoptosis, and enhancing mitochondrial function. Thus, FPATM-20 may be a novel agent for preventing skeletal muscle atrophy.
甲基乙二醛 (MGO) 是糖基化应激的强效前体，可导致糖尿病中的氧化应激和肌肉萎缩。榕属植物（Ficus pumila var. awkeotsang）衍生的 Spatheliachromen（FPATM-20）表现出潜在的抗氧化活性。
本研究旨在评估 FPATM-20 对 MGO 诱导的小鼠骨骼肌 C2C12 肌管萎缩和线粒体功能障碍的潜在影响及其潜在机制。
通过免疫荧光、酶联免疫吸附测定和 Western blot 评估萎缩和抗氧化因子。使用 ATP 测定法和 Seahorse Cell Mito Stress Test 评估线粒体功能。通过过碘酸-Schiff 染色测定糖原含量。进行分子对接以确定 FPATM-20 与 Keap1 的相互作用。
在 MGO 处理的肌管中，FPATM-20 激活了 Nrf2 通路，降低了 ROS 水平，增强了抗氧化防御，并增加了糖原含量。FPATM-20 提高了肌管的活力和大小，上调了肌球蛋白重链（MyHC）的表达，调节了泛素蛋白酶体分子（核 FoxO3a、atrogin-1、MuRF-1 和 p62/SQSTM1），并抑制了细胞凋亡（Bax/Bcl-2 比值和 cleaved caspase 3）。此外，FPATM-20 恢复了线粒体功能，包括线粒体膜电位、线粒体耗氧率和线粒体生物发生途径（核 PGC-1α/TFAM/FNDC5）。用 ML385 抑制 Nrf2 逆转了 FPATM-20 对 MGO 的作用。此外，分子对接证实了 FPATM-20 与 Nrf2 抑制剂 Keap1 的结合，表明 Nrf2 在保护作用中起关键作用。
FPATM-20 通过激活 Nrf2 抗氧化防御、减少蛋白降解和细胞凋亡以及增强线粒体功能来保护肌管免受 MGO 毒性的影响。因此，FPATM-20 可能是预防骨骼肌萎缩的一种新型药物。
