Department of Cardiology, The Second Hospital of Hebei Medical University, China.
Am J Med Sci. 2012 Mar;343(3):220-6. doi: 10.1097/MAJ.0b013e31822993ff.
The new adipocytokine visfatin is closely associated with the cardiovascular diseases, and expression of visfatin is elevated in the heart failure patients. However, at the cellular level, little work has been done on visfatin expression in the cardiomyocyte hypertrophy. Here, the authors investigated the expression and mechanisms of visfatin in angiotensin II (Ang II)-induced cardiomyocyte hypertrophy in vitro by means of the cultured neonatal rat cardiomyocytes.
After primary culture of 2- to 3-day-old Sprague-Dawley rat cardiomyocytes and cardiac fibroblasts, cardiomyocytes were pretreated with Ang II. Ang II type-1 receptor (AT1-R) antagonist telmisartan and Ang II type-2 receptor antagonist PD123319 were used to block effects of Ang II. These inhibitors used for the AT1-R pathway determination included SP600125, AG490 and U0126. Cell viability was examined using the 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay. The expression of visfatin was examined by means of reverse transcription-polymerase chain reaction and Western blot. The expression of brain natriuretic peptide was examined through western-blot analysis.
Visfatin was found expressed in cardiomyocytes as well as cardiac fibroblasts, and there was no significant difference at the mRNA and protein levels of visfatin. Ang II treatment induced the increased expression of visfatin and brain natriuretic peptide in a dose- and time-dependent manner in cardiomyocytes, and pretreatment with AT1-R antagonist telmisartan completely blocked Ang II-induced visfatin expression increasement. The increased visfatin expression was also blocked by the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway inhibitor AG490.
Visfatin expression was increased mainly through the AT1-R-JAK/STAT pathway in the process of Ang II-induced cardiomyocyte hypertrophy.
新的脂肪细胞因子内脂素与心血管疾病密切相关，心力衰竭患者的内脂素表达升高。然而，在细胞水平上，关于心肌细胞肥大中内脂素的表达，研究甚少。在此，作者通过培养新生大鼠心肌细胞，研究了 Ang II 诱导的心肌细胞肥大过程中内脂素的表达及其机制。
原代培养 2-3 天龄的 SD 大鼠心肌细胞和心肌成纤维细胞，用 Ang II 预处理心肌细胞。Ang II 型 1 受体（AT1-R）拮抗剂替米沙坦和 Ang II 型 2 受体拮抗剂 PD123319 用于阻断 Ang II 的作用。这些用于 AT1-R 通路测定的抑制剂包括 SP600125、AG490 和 U0126。通过 3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐测定法检测细胞活力。通过逆转录-聚合酶链反应和 Western blot 检测内脂素的表达。通过 Western blot 分析检测脑钠肽的表达。
内脂素在心肌细胞和心肌成纤维细胞中均有表达，mRNA 和蛋白水平均无显著差异。Ang II 处理以剂量和时间依赖的方式诱导心肌细胞内脂素和脑钠肽表达增加，AT1-R 拮抗剂替米沙坦预处理完全阻断 Ang II 诱导的内脂素表达增加。Janus 激酶/信号转导和转录激活因子（JAK/STAT）通路抑制剂 AG490 也阻断了内脂素表达的增加。
在 Ang II 诱导的心肌细胞肥大过程中，内脂素表达主要通过 AT1-R-JAK/STAT 通路增加。
