去甲肾上腺素对脂多糖活化血管内皮细胞的促／抗凋亡作用及其相关机制的研究

Endothelial cell injury is the crucial in sepsis-induced organ failure. In this project, the effect of norepinephrine (NE) on apoptosis of activated endothelial cells by overwhelming inflammatory mediators will be simulated in vitro in human umbilical vein endothelial cells (HUVEC), and the possible mechanisms will be investigated. The first, we will prove that low concentration of NE (<1μM) plays an anti-apoptosis role via attenuating LPS-induced decrease of NO production derived from eNOS. On the contrary, high concentration of NE (>10μM) induces more ROS production to promote LPS activated HUVEC apoptosis. Additionally, using specific inhibitors for pretreatment, we further try to identify that these pro-/anti-apoptotic effects of high or low dose of NE are mediated by stimulating α1 o rβ1 adrenergic receptor (AR). Finally, we will investigate whether the pro-/anti-apoptotic effects of low or high dose of NE are mediated through regulating intracellular cAMP production, which subsequently activates cAMP-dependent signal pathway to initiate the process of apoptosis in LPS activated HUVEC..This project raises a new insight of low or high concentration of NE switches a pro- or anti-apoptotic role through cAMP/PKA or cAMP/Epac signal pathway in LPS-activated HUVEC via specific stimulation of or β1 or α1 AR regulating ROS or NO production. Notably, the results could be rapidly translated into clinical practices.

血管内皮细胞损伤是脓毒症诱导多器官衰竭的关键。本项目采用人脐静脉血管内皮细胞（HUVEC）为研究对象，探索去甲肾上腺素（NE）对已受到炎症介质活化的内皮细胞凋亡的影响，并探索相关机制。首先，证实低浓度NE(<1μM)通过减轻LPS诱导eNOS合成NO活性降低的作用而抑制细胞凋亡；相反，高浓度NE(>10μM) 更多诱导ROS生成而促进细胞凋亡。其次，应用特异性阻滞剂预处理，进一步求证兴奋α1或β1受体分别介导了上述低与高浓度NE的抗或促凋亡作用。最后，运用siRNA静默等手段调控激酶活性，探索不同浓度NE是否通过cAMP依赖的信号通路产生抑制或促进受LPS活化内皮细胞凋亡的作用。.该项目创新性提出不同浓度NE通过兴奋β1或α1受体调节ROS和NO生成、并经cAMP/PKA 或cAMP/Epac 信号通路产生促或抗活化内皮细胞凋亡的作用，该研究结果可迅速转化为临床干预措施。