Khapchaev Asker Y, Vorotnikov Alexander V, Antonova Olga A, Samsonov Mikhail V, Shestakova Ekaterina A, Sklyanik Igor A, Tomilova Alina O, Shestakova Marina V, Shirinsky Vladimir P
Institute of Experimental Cardiology Named after Academician V.N. Smirnov, National Medical Research Center of Cardiology Named after Academician E.I. Chazov, Moscow 121552, Russia.
Diabetes Institute, Endocrinology Research Center, Moscow 117036, Russia.
Biomedicines. 2024 Feb 1;12(2):339. doi: 10.3390/biomedicines12020339.
Saturated free fatty acids are thought to play a critical role in metabolic disorders associated with obesity, insulin resistance, type 2 diabetes (T2D), and their vascular complications via effects on the vascular endothelium. The most abundant saturated free fatty acid, palmitate, exerts lipotoxic effects on the vascular endothelium, eventually leading to cell death. Shear stress activates the endothelial AMP-activated protein kinase (AMPK), a cellular energy sensor, and protects endothelial cells from lipotoxicity, however their relationship is uncertain. Here, we used isoform-specific shRNA-mediated silencing of AMPK to explore its involvement in the long-term protection of macrovascular human umbilical vein endothelial cells (HUVECs) against palmitate lipotoxicity and to relate it to the effects of shear stress. We demonstrated that it is the α1 catalytic subunit of AMPK that is critical for HUVEC protection under static conditions, whereas AMPK-α2 autocompensated a substantial loss of AMPK-α1, but failed to protect the cells from palmitate. Shear stress equally protected the wild type HUVECs and those lacking either α1, or α2, or both AMPK-α isoforms; however, the protective effect of AMPK reappeared after returning to static conditions. Moreover, in human adipose microvascular endothelial cells isolated from obese diabetic individuals, shear stress was a strong protector from palmitate lipotoxicity, thus highlighting the importance of circulation that is often obstructed in obesity/T2D. Altogether, these results indicate that AMPK is important for vascular endothelial cell protection against lipotoxicity in the static environment, however it may be dispensable for persistent and more effective protection exerted by shear stress.
饱和游离脂肪酸被认为通过对血管内皮的影响，在与肥胖、胰岛素抵抗、2型糖尿病（T2D）及其血管并发症相关的代谢紊乱中起关键作用。最丰富的饱和游离脂肪酸棕榈酸酯对血管内皮产生脂毒性作用，最终导致细胞死亡。剪切应力激活内皮细胞中的AMP激活蛋白激酶（AMPK），一种细胞能量传感器，并保护内皮细胞免受脂毒性，但它们之间的关系尚不确定。在这里，我们使用亚型特异性shRNA介导的AMPK沉默来探索其在大血管人脐静脉内皮细胞（HUVEC）长期抵抗棕榈酸酯脂毒性保护中的作用，并将其与剪切应力的影响联系起来。我们证明，在静态条件下，AMPK的α1催化亚基对HUVEC保护至关重要，而AMPK-α2可部分代偿AMPK-α1的大量缺失，但无法保护细胞免受棕榈酸酯的影响。剪切应力同样保护野生型HUVEC以及缺乏α1、α2或两种AMPK-α亚型的细胞；然而，回到静态条件后，AMPK的保护作用再次出现。此外，在从肥胖糖尿病个体分离的人脂肪微血管内皮细胞中，剪切应力是抵抗棕榈酸酯脂毒性的强大保护因素，从而突出了在肥胖/T2D中经常受阻的循环的重要性。总之，这些结果表明，AMPK在静态环境中对血管内皮细胞抵抗脂毒性保护很重要，但对于剪切应力所施加的持续且更有效的保护可能并非必需。
