Cardiovascular Department, Cardiovascular Research Institute of Traditional Chinese Medicine, Shuguang Hospital of Shanghai University of Traditional Chinese Medicine, Shanghai 201203, China.
Medical College of Georgia, Augusta University, Augusta, GA, USA.
Acta Pharmacol Sin. 2018 Apr;39(4):569-578. doi: 10.1038/aps.2018.19. Epub 2018 Mar 15.
Cardiac mesenchymal stem cells (C-MSCs) are endogenous cardiac stromal cells that play a role in heart repair after injury. C-MSC-derived exosomes (Exo) have shown protective effects against apoptosis induced by acute myocardial ischemia/reperfusion. Suxiao Jiuxin pill (SJP) is a traditional Chinese medicine (TCM) formula used in China for the treatment of acute myocardial ischemia, which contains tetramethylpyrazine (TMP) and borneol (BOR) as major components. In this study, we investigated whether SJP treatment affected exosome release from C-MSCs in vitro. C-MSCs prepared from mice were treated with SJP (62.5 μg/mL), TMP (25 μg/mL) or BOR (15 μg/mL). Using an acetylcholinesterase activity assay, we found that both SJP and TMP treatment significantly increased exosome secretion compared to the control ethanol treatment. The neutral sphingomyelinase 2 (nSMase2) pathway was important in exosome formation and packaging. But neither the level of nSMase2 mRNA nor the level of protein changed following SJP, TMP or BOR treatment, suggesting that SJP stimulated exosome release via an nSMase2-independent pathway. The Rab27a and Rab27b GTPases controlled different steps of the exosome secretion pathway. We showed that SJP treatment significantly increased the protein levels of Rab27a, SYTL4 (Rab27a effector) and Rab27b compared with the control treatment. SJP treatment also significantly upregulated the mRNA level of Rab27b, rather than Rab27a. Moreover, SJP-induced increase of C-MSC-exosome release was inhibited by Rab27b knockdown, suggesting that SJP promotes exosome secretion from C-MSCs via a GTPase-dependent pathway. This study reveals a novel mechanism for SJP in modulating cardiac homeostasis.
心脏间充质干细胞(C-MSCs)是内源性的心脏基质细胞,在损伤后对心脏修复起作用。C-MSC 衍生的外泌体(Exo)已显示出对急性心肌缺血/再灌注诱导的细胞凋亡有保护作用。速效救心丸(SJP)是一种中国传统中药(TCM)配方,用于治疗急性心肌缺血,其主要成分包括四甲基吡嗪(TMP)和冰片(BOR)。在这项研究中,我们研究了 SJP 处理是否会影响体外 C-MSC 释放外泌体。用 SJP(62.5μg/ml)、TMP(25μg/ml)或 BOR(15μg/ml)处理从小鼠中分离得到的 C-MSCs。通过乙酰胆碱酯酶活性测定,我们发现与对照乙醇处理相比,SJP 和 TMP 处理均显著增加外泌体分泌。中性鞘磷脂酶 2(nSMase2)途径在外泌体形成和包装中起重要作用。但是,SJP、TMP 或 BOR 处理后,nSMase2 mRNA 水平和蛋白水平均未发生变化,提示 SJP 通过 nSMase2 非依赖性途径刺激外泌体释放。Rab27a 和 Rab27b GTPases 控制外泌体分泌途径的不同步骤。我们表明,与对照处理相比,SJP 处理显著增加了 Rab27a、SYTL4(Rab27a 效应物)和 Rab27b 的蛋白水平。SJP 处理还显著上调了 Rab27b 的 mRNA 水平,而不是 Rab27a。此外,Rab27b 敲低抑制了 SJP 诱导的 C-MSC 外泌体释放增加,提示 SJP 通过 GTPase 依赖性途径促进 C-MSC 释放外泌体。这项研究揭示了 SJP 调节心脏内稳态的新机制。