Department of Cardiology, Chinese PLA General Hospital, Beijing 100853, China.
Department of Cardiology, Chinese PLA General Hospital, Beijing 100853, China.
Free Radic Biol Med. 2014 Dec;77:363-75. doi: 10.1016/j.freeradbiomed.2014.09.033. Epub 2014 Oct 16.
Adipose-derived mesenchymal stem cells (ADMSCs)-based therapy is a promising modality for the treatment of myocardial infarction in the future. However, the majority of transplanted cells are readily lost after transplantation because of hypoxia and oxidative stress. An efficient means to enhance the ability of ADMSCs to survive under pathologic conditions is required. In our study, we explored the effects of exendin-4 (Ex-4) on ADMSCs apoptosis in vitro induced by hydrogen peroxide, focusing in particular on mitochondrial apoptotic pathways and PI3K/Akt-secreted frizzled-related protein 2 (Sfrp2) survival signaling. We demonstrated that ADMSCs subjected to H2O2 for 12h exhibited impaired mitochondrial function and higher apoptotic rate. However, Ex-4 (1-20 nM) preconditioning for 12h could protect ADMSCs against H2O2-mediated apoptosis in a dose-dependent manner. Furthermore, Ex-4 pretreatment upregulated the levels of superoxide dismutase and glutathione as well as downregulating the production of reactive oxygen species and malondialdehyde. Western blots revealed that increased antiapoptotic proteins Bcl-2 and c-IAP1/2 as well as decreased proapoptotic proteins Bax and cytochrome c appeared in ADMSCs with Ex-4 incubation, which inhibited the caspase-9-involved mitochondrial apoptosis pathways with evidence showing inactivation of caspase-9/3 and preservation of mitochondrial membrane potential. Furthermore, we illustrated that Ex-4 enhanced Akt phosphorylation, which increased the expression of Sfrp2. Notably, blockade of the PI3K/Akt pathway or knockdown of Sfrp2 with siRNA obviously abolished the protective effects of Ex-4 on mitochondrial function and ADMSCs apoptosis under H2O2. In summary, this study confirmed that H2O2 induced ADMSCs apoptosis through mitochondria-dependent cell death pathways, and Ex-4 preconditioning may reduce such apoptosis of ADMSCs through the PI3K/Akt-Sfrp2 pathways.
脂肪间充质干细胞（ADMSC）为基础的治疗是一种有前途的治疗心肌梗死的方法。然而，由于缺氧和氧化应激，大多数移植的细胞在移植后很容易丢失。需要一种有效的方法来增强 ADMSC 在病理条件下的存活能力。在我们的研究中，我们探讨了外泌素 4（Ex-4）对 ADMSC 在体外由过氧化氢诱导的细胞凋亡的影响，特别是关注线粒体凋亡途径和 PI3K/Akt-分泌卷曲相关蛋白 2（Sfrp2）生存信号。我们证明，ADMSC 在过氧化氢作用 12 小时后，线粒体功能受损，凋亡率较高。然而，Ex-4（1-20 nM）预处理 12 小时可以以剂量依赖的方式保护 ADMSC 免受 H2O2 介导的凋亡。此外，Ex-4 预处理上调了超氧化物歧化酶和谷胱甘肽的水平，同时降低了活性氧和丙二醛的产生。Western blot 显示，在 Ex-4 孵育的 ADMSC 中，抗凋亡蛋白 Bcl-2 和 c-IAP1/2 的水平增加，促凋亡蛋白 Bax 和细胞色素 c 的水平降低，表明 caspase-9 参与的线粒体凋亡途径被抑制，caspase-9/3 失活，线粒体膜电位得以维持。此外，我们还表明，Ex-4 增强了 Akt 的磷酸化，从而增加了 Sfrp2 的表达。值得注意的是，PI3K/Akt 通路的阻断或 Sfrp2 的 siRNA 敲低明显消除了 Ex-4 对 H2O2 下线粒体功能和 ADMSC 凋亡的保护作用。综上所述，本研究证实了 H2O2 通过线粒体依赖性细胞死亡途径诱导 ADMSC 凋亡，而 Ex-4 预处理可能通过 PI3K/Akt-Sfrp2 途径减少 ADMSC 的这种凋亡。
