AMPK Profiling in Rodent and Human Pancreatic Beta-Cells under Nutrient-Rich Metabolic Stress
AMPK Profiling in Rodent and Human Pancreatic Beta-Cells under Nutrient-Rich Metabolic Stress
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DOI：
10.3390/ijms21113982
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发表时间：
2020-06-01
影响因子：
5.6
通讯作者：
Maechler, Pierre
中科院分区：
文献类型：
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作者：
Brun, Thierry;Jimenez-Sanchez, Cecilia;Maechler, Pierre
胰腺β细胞长期暴露于升高的营养水平会损害其功能并可能诱导细胞凋亡。与其他细胞类型一样，AMPK在营养缺乏的条件下在β细胞中被激活，而对AMPK对代谢应激的反应知之甚少。在这里，我们首先回顾了最近关于AMPK激活在β细胞中的作用的研究。然后，我们研究了代谢应激后β细胞中AMPK通路的表达谱。将INS-1 E β细胞和人胰岛暴露于葡萄糖（5.5-25 mM）、棕榈酸盐或油酸盐（0.4 mM）和果糖（5.5 mM）3天。在这些处理之后，我们通过qRT-PCR分析了INS-1 E β细胞的转录水平，并通过RNA-Seq分析了人类胰岛的转录水平;特别关注AMPK相关基因，如AMPK催化亚基α 1（Prkaa 1）和α 2（Prkaa 2）。AMPK α和pAMPK α也通过免疫印迹在蛋白质水平上进行评价。慢性暴露于不同的代谢应激，已知改变葡萄糖刺激的胰岛素分泌，没有改变AMPK的表达，无论是在胰岛素瘤细胞或人类胰岛。6个AMPK亚基的表达谱被不同的致糖尿病条件略微修饰。然而，一些上游激酶和下游AMPK靶点（包括K-ATP通道亚基）的表达表现出应激特异性特征。有趣的是，在蛋白质水平，慢性果糖治疗有利于人类胰岛中的禁食样表型，如AMPK激活所证明的。总的来说，以前发表的和目前的数据表明，在β细胞中，AMPK激活可能与糖尿病前期状态有关，可能是一种保护机制。
Chronic exposure of pancreatic beta-cells to elevated nutrient levels impairs their function and potentially induces apoptosis. Like in other cell types, AMPK is activated in beta-cells under conditions of nutrient deprivation, while little is known on AMPK responses to metabolic stresses. Here, we first reviewed recent studies on the role of AMPK activation in beta-cells. Then, we investigated the expression profile of AMPK pathways in beta-cells following metabolic stresses. INS-1E beta-cells and human islets were exposed for 3 days to glucose (5.5-25 mM), palmitate or oleate (0.4 mM), and fructose (5.5 mM). Following these treatments, we analyzed transcript levels of INS-1E beta-cells by qRT-PCR and of human islets by RNA-Seq; with a special focus on AMPK-associated genes, such as the AMPK catalytic subunits alpha 1 (Prkaa1) and alpha 2 (Prkaa2). AMPK alpha and pAMPK alpha were also evaluated at the protein level by immunoblotting. Chronic exposure to the different metabolic stresses, known to alter glucose-stimulated insulin secretion, did not change AMPK expression, either in insulinoma cells or in human islets. Expression profile of the six AMPK subunits was marginally modified by the different diabetogenic conditions. However, the expression of some upstream kinases and downstream AMPK targets, including K-ATP channel subunits, exhibited stress-specific signatures. Interestingly, at the protein level, chronic fructose treatment favored fasting-like phenotype in human islets, as witnessed by AMPK activation. Collectively, previously published and present data indicate that, in the beta-cell, AMPK activation might be implicated in the pre-diabetic state, potentially as a protective mechanism.