Benzimidazole derivative small-molecule 991 enhances AMPK activity and glucose uptake induced by AICAR or contraction in skeletal muscle.
Benzimidazole derivative small-molecule 991 enhances AMPK activity and glucose uptake induced by AICAR or contraction in skeletal muscle.
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DOI：
10.1152/ajpendo.00237.2016
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发表时间：
2016-10-01
期刊：
影响因子：
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通讯作者：
Sakamoto K
中科院分区：
文献类型：
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作者：
Bultot L;Jensen TE;Lai YC;Madsen AL;Collodet C;Kviklyte S;Deak M;Yavari A;Foretz M;Ghaffari S;Bellahcene M;Ashrafian H;Rider MH;Richter EA;Sakamoto K
AMP活化蛋白激酶（AMPK）在维持能量平衡中起着多种作用，并协调复杂的代谢途径。这可以通过以下事实来解释：AMPK作为多个异源三聚体复合物存在，所述复合物包含催化α亚基（α1和α2）和调节β（β1和β2）-和γ（γ1，γ2，γ3）-亚基，其独特地分布在不同的细胞类型中。人们对开发用于治疗用途和作为研究工具的特异性和亚型选择性AMPK激活药物有浓厚的兴趣。此外，建立增强细胞AMPK活性的方法将有利于这两个目的。在这里，我们研究了最近描述的称为991的有效AMPK激活剂，与常用的激活剂5-氨基咪唑-4-甲酰胺核苷或收缩相结合，进一步增强AMPK活性和葡萄糖转运在小鼠骨骼肌离体。鉴于γ3亚基仅在骨骼肌中表达，并参与收缩诱导的葡萄糖转运，我们测量了AMPKγ3以及普遍表达的含γ1复合物的活性。我们最初使用AMPK缺陷小鼠模型验证了用于评估亚型特异性AMPK活性的抗体的特异性。我们观察到，低剂量的991（5 μM）刺激了含γ1和γ3的AMPK复合物的适度或可忽略的活性。引人注目的是，与任何单一处理相比，991和5-氨基咪唑-4-甲酰胺核苷或991和收缩的双重处理显著增强了AMPKγ1/γ3复合物的激活和葡萄糖转运。该研究证明了双重激活剂方法的实用性，以实现AMPK的更大激活和各种细胞类型（包括骨骼肌）的下游生理反应。
AMP-activated protein kinase (AMPK) plays diverse roles and coordinates complex metabolic pathways for maintenance of energy homeostasis. This could be explained by the fact that AMPK exists as multiple heterotrimer complexes comprising a catalytic α-subunit (α1 and α2) and regulatory β (β1 and β2)- and γ (γ1, γ2, γ3)-subunits, which are uniquely distributed across different cell types. There has been keen interest in developing specific and isoform-selective AMPK-activating drugs for therapeutic use and also as research tools. Moreover, establishing ways of enhancing cellular AMPK activity would be beneficial for both purposes. Here, we investigated if a recently described potent AMPK activator called 991, in combination with the commonly used activator 5-aminoimidazole-4-carboxamide riboside or contraction, further enhances AMPK activity and glucose transport in mouse skeletal muscle ex vivo. Given that the γ3-subunit is exclusively expressed in skeletal muscle and has been implicated in contraction-induced glucose transport, we measured the activity of AMPKγ3 as well as ubiquitously expressed γ1-containing complexes. We initially validated the specificity of the antibodies for the assessment of isoform-specific AMPK activity using AMPK-deficient mouse models. We observed that a low dose of 991 (5 μM) stimulated a modest or negligible activity of both γ1- and γ3-containing AMPK complexes. Strikingly, dual treatment with 991 and 5-aminoimidazole-4-carboxamide riboside or 991 and contraction profoundly enhanced AMPKγ1/γ3 complex activation and glucose transport compared with any of the single treatments. The study demonstrates the utility of a dual activator approach to achieve a greater activation of AMPK and downstream physiological responses in various cell types, including skeletal muscle.