Xu Shengjie, Zhao Yanbo, Jin Chongying, Yu Lu, Ding Fang, Fu Guosheng, Zhu Junhui
Department of Cardiology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University Hangzhou 310016, China.
The Province Center for Cardio-Cerebral-Vascular Disease, Zhejiang Hospital Hangzhou, Zhejiang, China.
Am J Transl Res. 2017 Mar 15;9(3):1037-1048. eCollection 2017.
Increasing evidence suggests that EPCs improve neovascularization and endothelial regeneration via the production of paracrine factors. VEGF and IL-8 are major cytokines involved in EPC-mediated angiogenesis and re-endothelialization. In our previous studies, Hcy impaired EPC migratory and adhesive activities. We devised this study to determine whether Hcy could affect the expression and secretion of VEGF and IL-8 from EPCs. We found that high levels of Hcy (100-500 μM) decreased the EPC-mediated protein secretion and mRNA expression of VEGF and IL-8. Moreover, PIO, a PPARγ agonist, has been suggested to regulate EPC adhesion, migration, survival. In this study, PIO normalized the production of these cytokines by EPCs stimulated with Hcy. These effects of Hcy and PIO were primarily mediated by PKC and ROS via NADPH oxidase. We further confirmed this mechanism via knockdown of the NADPH oxidase subunits p67phox and Nox2. Furthermore, the PPARγ inhibitor GW9662 was not observed to abrogate the beneficial effect of PIO, indicating that PIO protected EPC paracrine function against Hcy in a PPARγ-independent manner.
越来越多的证据表明，内皮祖细胞（EPCs）通过分泌旁分泌因子来促进新血管形成和内皮再生。血管内皮生长因子（VEGF）和白细胞介素-8（IL-8）是参与EPC介导的血管生成和再内皮化的主要细胞因子。在我们之前的研究中，同型半胱氨酸（Hcy）损害了EPC的迁移和黏附活性。我们设计了本研究以确定Hcy是否会影响EPCs中VEGF和IL-8的表达与分泌。我们发现，高水平的Hcy（100 - 500 μM）会降低EPC介导的VEGF和IL-8的蛋白分泌及mRNA表达。此外，已表明过氧化物酶体增殖物激活受体γ（PPARγ）激动剂吡格列酮（PIO）可调节EPC的黏附、迁移和存活。在本研究中，PIO使受Hcy刺激的EPCs产生的这些细胞因子恢复正常。Hcy和PIO的这些作用主要通过蛋白激酶C（PKC）和经由烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶产生的活性氧（ROS）介导。我们通过敲低NADPH氧化酶亚基p67phox和Nox2进一步证实了这一机制。此外，未观察到PPARγ抑制剂GW9662消除PIO的有益作用，这表明PIO以不依赖PPARγ的方式保护EPC旁分泌功能免受Hcy影响。
