Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain; Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Canary Islands, Spain.
Research Institute of Biomedical and Health Sciences (IUIBS), University of Las Palmas de Gran Canaria, Canary Islands, Spain; Department of Mathematics, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain.
Free Radic Biol Med. 2024 Sep;222:607-624. doi: 10.1016/j.freeradbiomed.2024.07.012. Epub 2024 Jul 14.
Autophagy is essential for the adaptive response to exercise and physiological skeletal muscle functionality. However, the mechanisms leading to the activation of macroautophagy and chaperone-mediated autophagy in human skeletal muscle in response to high-intensity exercise remain elusive. Our findings demonstrate that macroautophagy and chaperone-mediated autophagy are stimulated by high-intensity exercise in normoxia (PO: 143 mmHg) and severe acute hypoxia (PO: 73 mmHg) in healthy humans. High-intensity exercise induces macroautophagy initiation through AMPKα phosphorylation, which phosphorylates and activates ULK1. ULK1 phosphorylates BECN1 at Ser, eliciting the dissociation of BECN1-BCL2 crucial for phagophore formation. Besides, high-intensity exercise elevates the LC3B-II:LC3B-I ratio, reduces total SQSTM1/p62 levels, and induces p-Ser SQSTM1/p62 phosphorylation, suggesting heightened autophagosome degradation. PHAF1/MYTHO, a novel macroautophagy biomarker, is highly upregulated in response to high-intensity exercise. The latter is accompanied by elevated LAMP2A expression, indicating chaperone-mediated autophagy activation regardless of post-exercise HSPA8/HSC70 downregulation. Despite increased glycolytic metabolism, severe acute hypoxia does not exacerbate the autophagy signaling response. Signaling changes revert within 1 min of recovery with free circulation, while the application of immediate post-exercise ischemia impedes recovery. Our study concludes that macroautophagy and chaperone-mediated autophagy pathways are strongly activated by high-intensity exercise, regardless of PO, and that oxygenation is necessary to revert these signals to pre-exercise values. PHAF1/MYTHO emerges as a pivotal exercise-responsive autophagy marker positively associated with the LC3B-II:LC3B-I ratio.
自噬对于运动适应和生理骨骼肌功能至关重要。然而，高强度运动引起人骨骼肌巨自噬和伴侣介导自噬的机制仍不清楚。我们的研究结果表明，在常氧（PO：143mmHg）和严重急性低氧（PO：73mmHg）条件下，高强度运动均可刺激健康人巨自噬和伴侣介导自噬。高强度运动通过 AMPKα磷酸化诱导自噬起始，磷酸化并激活 ULK1。ULK1 在 Ser 位点磷酸化 BECN1，引发对噬泡形成至关重要的 BECN1-BCL2 解离。此外，高强度运动增加 LC3B-II:LC3B-I 比值，降低总 SQSTM1/p62 水平，并诱导 p-Ser SQSTM1/p62 磷酸化，表明自噬体降解增加。PHAF1/MYTHO，一种新的巨自噬生物标志物，对高强度运动有高度上调反应。后者伴随着 LAMP2A 表达的升高，表明伴侣介导的自噬激活，而与运动后 HSPA8/HSC70 的下调无关。尽管糖酵解代谢增加，严重急性低氧不会加剧自噬信号反应。信号变化在恢复后 1 分钟内恢复，而运动后即刻缺血会阻碍恢复。本研究得出结论，巨自噬和伴侣介导的自噬途径在高强度运动下被强烈激活，与 PO 无关，氧合对于将这些信号恢复到运动前水平是必要的。PHAF1/MYTHO 作为一个关键的运动反应性自噬标志物出现，与 LC3B-II:LC3B-I 比值呈正相关。
