PPARβ activation restores the high glucose-induced impairment of insulin signalling in endothelial cells
PPARβ activation restores the high glucose-induced impairment of insulin signalling in endothelial cells
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DOI：
10.1111/bph.12646
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发表时间：
2014-06-01
影响因子：
7.3
通讯作者：
Duarte, J.
中科院分区：
文献类型：
--
作者：
Quintela, A. M.;Jimenez, R.;Duarte, J.
背景与目的PPAR增强脂肪细胞和骨骼肌细胞的胰岛素敏感性，但其对内皮细胞胰岛素信号传导的影响尚不清楚。我们分析了PPAR/ (PPAR)激动剂GW0742和L165041对糖尿病大鼠HUVECs、主动脉和肠系膜动脉高糖诱导的胰岛素信号受损的影响。实验方法在低糖或高糖培养基中培养HUVECs，研究胰岛素刺激NO的产生、Akt-Ser473和eNOS-Ser1177磷酸化以及活性氧（ROS）的产生。还分析了链脲佐菌素（STZ）诱导的糖尿病大鼠血管中胰岛素刺激的松弛和蛋白磷酸化。在高糖培养基中培养的HUVECs显示胰岛素刺激下NO的产生显著减少。高糖还降低了胰岛素诱导的Akt-Ser473和eNOS-Ser1177磷酸化，增加了IRS-1-Ser636和ERK1/2-Thr183-Tyr185磷酸化，增加了ROS的产生。与PPAR激动剂GW0742或L165041共孵生可阻止高糖诱导的所有这些影响。反过来，当HUVEC与PPAR拮抗剂GSK0660、丙酮酸脱氢酶激酶（PDK）4抑制剂二氯乙酸一起孵卵或用siRNA敲除PPAR和PDK4后，激动剂诱导的作用被抑制。ERK1/2抑制剂PD98059、活性氧清除剂过氧化氢酶、配合物II烯酰三氟丙酮抑制剂或氧化磷酸化解耦剂羰基氰化物间氯苯腙也能预防葡萄糖诱导的胰岛素抵抗。在STZ糖尿病大鼠中，口服GW0742也能改善胰岛素信号传导和一氧化氮介导的血管松弛受损。结论和意义PPAR在体外和体内激活可恢复内皮功能，至少部分通过PDK4激活保护高糖损伤的胰岛素- akt - enos通路。
Background and Purpose PPAR enhances insulin sensitivity in adipocytes and skeletal muscle cells, but its effects on insulin signalling in endothelial cells are not known. We analysed the effects of the PPAR/ (PPAR) agonists, GW0742 and L165041, on impaired insulin signalling induced by high glucose in HUVECs and aortic and mesenteric arteries from diabetic rats. Experimental Approach Insulin-stimulated NO production, Akt-Ser473 and eNOS-Ser1177 phosphorylation, and reactive oxygen species (ROS) production were studied in HUVECs incubated in low- or high-glucose medium. Insulin-stimulated relaxations and protein phosphorylation in vessels from streptozotocin (STZ)-induced diabetic rats were also analysed. Key Results HUVECs incubated in high-glucose medium showed a significant reduction in insulin-stimulated production of NO. High glucose also reduced insulin-induced Akt-Ser473 and eNOS-Ser1177 phosphorylation, increased IRS-1-Ser636 and ERK1/2-Thr183-Tyr185 phosphorylation and increased ROS production. The co-incubation with the PPAR agonists GW0742 or L165041 prevented all these effects induced by high glucose. In turn, the effects induced by the agonists were suppressed when HUVEC were also incubated with the PPAR antagonist GSK0660, the pyruvate dehydrogenase kinase (PDK)4 inhibitor dichloroacetate or after knockdown of both PPAR and PDK4 with siRNA. The ERK1/2 inhibitor PD98059, ROS scavenger catalase, inhibitor of complex II thenoyltrifluoroacetone or uncoupler of oxidative phosphorylation, carbonyl cyanide m-chlorophenylhydrazone, also prevented glucose-induced insulin resistance. In STZ diabetic rats, oral GW0742 also improved insulin signalling and the impaired NO-mediated vascular relaxation. Conclusion and Implications PPAR activation in vitro and in vivo restores the endothelial function, preserving the insulin-Akt-eNOS pathway impaired by high glucose, at least in part, through PDK4 activation.