Department of Obstetrics and Gynecology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, USA.
Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA, USA.
Hypertens Res. 2019 Feb;42(2):155-164. doi: 10.1038/s41440-018-0150-1. Epub 2018 Dec 5.
Chymase is a major angiotensin-converting enzyme (ACE)-independent angiotensin convertase, and its expression is upregulated in the maternal vascular endothelium in preeclampsia, a hypertensive disorder in human pregnancy. Increased chymase-dependent angiotensin II generation has been reported in several cardiovascular diseases, including atherosclerosis and aneurysmal lesions. However, it remains unclear how chymase is activated. Histone modification is an important regulatory mechanism that controls gene expression. In this study, using a chymase overexpression cell model, we investigated the mechanisms of chymase activation to test our hypothesis that histone acetylation could promote endothelial chymase expression. Human umbilical vein endothelial cells were transfected with the chymase gene. Trichostatin A was used to inhibit histone deacetylases (HDACs). The expression levels of chymase, ACE, and HDACs were determined by western blotting. Our results showed that ACE was strongly expressed in control cells, but was significantly downregulated in cells transfected to express chymase. Strikingly, we also found that HDAC inhibition resulted in a dose-dependent increase in chymase expression but a dose-dependent decrease in ACE expression in cells transfected with the chymase gene. HDAC inhibition was confirmed by the decreased expression of HDAC1 and HDAC6 in cells treated with trichostatin A. Increased chymase expression associated with reduced histone deacetylase expression was further confirmed by immunostaining of subcutaneous adipose sections from women with preeclampsia. We conclude that aberrant HDAC expression/activity could disturb the balance between ACE and chymase expression in endothelial cells. Our results support the clinical importance of chymase as a new pharmacological target for cardiovascular disorders.
糜酶是一种主要的血管紧张素转换酶（ACE）非依赖性血管紧张素转换酶，其在子痫前期（人类妊娠中的一种高血压疾病）的母体血管内皮中表达上调。在几种心血管疾病中，包括动脉粥样硬化和动脉瘤病变，已经报道了增加的糜酶依赖性血管紧张素 II 生成。组蛋白修饰是控制基因表达的重要调节机制。在这项研究中，我们使用糜酶过表达细胞模型，研究了糜酶激活的机制，以检验我们的假设，即组蛋白乙酰化可以促进内皮糜酶表达。用人脐静脉内皮细胞转染糜酶基因。使用曲古抑菌素 A 抑制组蛋白去乙酰化酶（HDACs）。通过 Western blot 测定糜酶、ACE 和 HDACs 的表达水平。我们的结果表明，ACE 在对照细胞中强烈表达，但在转染表达糜酶的细胞中显著下调。令人惊讶的是，我们还发现，HDAC 抑制导致转染糜酶基因的细胞中糜酶表达呈剂量依赖性增加，而 ACE 表达呈剂量依赖性降低。用曲古抑菌素 A 处理的细胞中 HDAC1 和 HDAC6 的表达减少证实了 HDAC 抑制。在子痫前期妇女的皮下脂肪组织切片的免疫染色中进一步证实了与组蛋白去乙酰化酶表达减少相关的糜酶表达增加。我们得出结论，异常的 HDAC 表达/活性可能会干扰内皮细胞中 ACE 和糜酶表达之间的平衡。我们的结果支持糜酶作为心血管疾病新的药理学靶标的临床重要性。
