Sun Xiaoguang, Mathew Biji, Sammani Saad, Jacobson Jeffrey R, Garcia Joe G N
Department of Medicine, University of Arizona Health Sciences, Tucson, AZ, USA.
Division of Pulmonary, Critical Care, Sleep & Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.
Pulm Circ. 2017 Mar 21;7(1):117-125. doi: 10.1177/2045893217701162. eCollection 2017 Mar.
We have demonstrated that simvastatin and sphingosine 1-phosphate (S1P) both attenuate increased vascular permeability in preclinical models of acute respiratory distress syndrome. However, the underlying mechanisms remain unclear. As Krüppel-like factor 2 (KLF2) serves as a critical regulator for cellular stress response in endothelial cells (EC), we hypothesized that simvastatin enhances endothelial barrier function via increasing expression of the barrier-promoting S1P receptor, , via a KLF2-dependent mechanism. luciferase reporter promoter activity in human lung artery EC (HPAEC) was tested after simvastatin (5 μM), and S1PR1 and KLF2 protein expression detected by immunoblotting. , transcription and expression of S1PR1 and KLF2 in mice lungs were detected by microarray profiling and immunoblotting after exposure to simvastatin (10 mg/kg). Endothelial barrier function was measured by trans-endothelial electrical resistance with the S1PR1 agonist FTY720-(S)-phosphonate. Both and gene expression (mRNA, protein) were significantly increased by simvastatin and . promoter activity was significantly increased by simvastatin (< 0.05), which was significantly attenuated by KLF2 silencing (siRNA). Simvastatin induced KLF2 recruitment to the promoter, and consequently, significantly augmented the effects of the S1PR1 agonist on EC barrier enhancement ( < 0.05), which was significantly attenuated by KLF2 silencing ( < 0.05). These results suggest that simvastatin upregulates transcription and expression via the transcription factor KLF2, and consequently augments the effects of S1PR1 agonists on preserving vascular barrier integrity. These results may lead to novel combinatorial therapeutic strategies for lung inflammatory syndromes.
我们已经证明，在急性呼吸窘迫综合征的临床前模型中，辛伐他汀和1-磷酸鞘氨醇（S1P）均可减轻血管通透性增加。然而，其潜在机制仍不清楚。由于Krüppel样因子2（KLF2）是内皮细胞（EC）中细胞应激反应的关键调节因子，我们推测辛伐他汀通过KLF2依赖性机制增加促进屏障的S1P受体S1PR1的表达，从而增强内皮屏障功能。用辛伐他汀（5μM）处理后人肺动脉内皮细胞（HPAEC）中的荧光素酶报告基因启动子活性进行检测，并用免疫印迹法检测S1PR1和KLF2蛋白表达。通过微阵列分析和免疫印迹法检测小鼠肺暴露于辛伐他汀（10mg/kg）后S1PR1和KLF2的转录和表达。用S1PR1激动剂FTY720-（S）-膦酸盐通过跨内皮电阻测量内皮屏障功能。辛伐他汀使S1PR1和KLF2基因表达（mRNA、蛋白质）均显著增加。辛伐他汀使S1PR1启动子活性显著增加（<0.05），而KLF2沉默（siRNA）使其显著减弱。辛伐他汀诱导KLF2募集到S1PR1启动子，因此，显著增强了S1PR1激动剂对EC屏障增强的作用（<0.05），而KLF2沉默使其显著减弱（<0.05）。这些结果表明，辛伐他汀通过转录因子KLF2上调S1PR1转录和表达，从而增强S1PR1激动剂对维持血管屏障完整性的作用。这些结果可能会带来针对肺部炎症综合征的新型联合治疗策略。
