Inflammation, glucose, and vascular cell damage: the role of the pentose phosphate pathway.
Inflammation, glucose, and vascular cell damage: the role of the pentose phosphate pathway.
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DOI：
10.1186/s12933-016-0397-2
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发表时间：
2016-06-01
影响因子：
9.3
通讯作者：
Sánchez-Ferrer CF
中科院分区：
文献类型：
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作者：
Peiró C;Romacho T;Azcutia V;Villalobos L;Fernández E;Bolaños JP;Moncada S;Sánchez-Ferrer CF
高血糖症被认为是一种促炎性疾病，也是血管损伤的主要原因。然而，我们之前已经描述过，高葡萄糖只会促进人类血管细胞的炎症，这些血管细胞先前受到促炎刺激，如细胞因子白细胞介素（IL）1β。在这里，我们旨在确定高糖加剧il - 1β诱导的血管炎症的细胞机制。将培养的人主动脉平滑肌细胞（HASMC）和离体大鼠肠系膜微血管在含5.5 ~ 22 mmol/L葡萄糖的培养基中用il - 1β处理。在HASMC中测定葡萄糖摄取和消耗、乳酸生成、GLUT1水平、NADPH氧化酶活性和炎症信号（核因子-κB激活和诱导型一氧化氮合酶表达），同时测定大鼠微血管中对乙酰胆碱的内皮依赖性松弛。对il - 1受体、NADPH氧化酶和葡萄糖-6-磷酸脱氢酶（G6PD）进行药理抑制，并对G6PD进行沉默。测定戊糖磷酸途径（PPP）活性和还原性谷胱甘肽水平。我们发现，在22 mM葡萄糖中培养的HASMC中，过量的葡萄糖摄取仅在il - 1β激活后发生。然而，葡萄糖的简单进入并不足以有害，因为叠氮化钠抑制线粒体呼吸后葡萄糖转运蛋白GLUT1的过度表达或葡萄糖摄取增加并不足以触发炎症机制。事实上，除了允许葡萄糖进入外，il - 1β还激活了PPP，从而允许一些多余的葡萄糖通过这一途径代谢。这反过来导致NADPH氧化酶过度激活，导致自由基的产生增加以及随后的下游促炎信号传导。此外，在大鼠肠系膜微血管中，高糖培养增强了il - 1β诱导的内皮功能障碍，其机制被抑制PPP所消除。像il - 1β这样的促炎刺激通过引起葡萄糖摄取增加并随后转移到PPP，将多余的葡萄糖转化为血管有害物质，促进促氧化和促炎途径恶化所需的促氧化条件。我们认为PPP的过度激活是高血糖相关血管损伤的重要机制。本文的在线版本（doi:10.1186/s12933-016-0397-2）包含补充材料，可供授权用户使用。
Hyperglycemia is acknowledged as a pro-inflammatory condition and a major cause of vascular damage. Nevertheless, we have previously described that high glucose only promotes inflammation in human vascular cells previously primed with pro-inflammatory stimuli, such as the cytokine interleukin (IL)1β. Here, we aimed to identify the cellular mechanisms by which high glucose exacerbates the vascular inflammation induced by IL1β. Cultured human aortic smooth muscle cells (HASMC) and isolated rat mesenteric microvessels were treated with IL1β in medium containing 5.5–22 mmol/L glucose. Glucose uptake and consumption, lactate production, GLUT1 levels, NADPH oxidase activity and inflammatory signalling (nuclear factor-κB activation and inducible nitric oxide synthase expression) were measured in HASMC, while endothelium-dependent relaxations to acetylcholine were determined in rat microvessels. Pharmacological inhibition of IL1 receptors, NADPH oxidase and glucose-6-phosphate dehydrogenase (G6PD), as well as silencing of G6PD, were also performed. Moreover, the pentose phosphate pathway (PPP) activity and the levels of reduced glutathione were determined. We found that excess glucose uptake in HASMC cultured in 22 mM glucose only occurred following activation with IL1β. However, the simple entry of glucose was not enough to be deleterious since over-expression of the glucose transporter GLUT1 or increased glucose uptake following inhibition of mitochondrial respiration by sodium azide was not sufficient to trigger inflammatory mechanisms. In fact, besides allowing glucose entry, IL1β activated the PPP, thus permitting some of the excess glucose to be metabolized via this route. This in turn led to an over-activation NADPH oxidase, resulting in increased generation of free radicals and the subsequent downstream pro-inflammatory signalling. Moreover, in rat mesenteric microvessels high glucose incubation enhanced the endothelial dysfunction induced by IL1β by a mechanism which was abrogated by the inhibition of the PPP. A pro-inflammatory stimulus like IL1β transforms excess glucose into a vascular deleterious agent by causing an increase in glucose uptake and its subsequent diversion into the PPP, promoting the pro-oxidant conditions required for the exacerbation of pro-oxidant and pro-inflammatory pathways. We propose that over-activation of the PPP is a crucial mechanism for the vascular damage associated to hyperglycemia. The online version of this article (doi:10.1186/s12933-016-0397-2) contains supplementary material, which is available to authorized users.