Department of Thoracic and Cardiovascular Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu 210029, P.R. China.
Department of Thoracic Cardiovascular Surgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China.
Mol Med Rep. 2018 May;17(5):7170-7176. doi: 10.3892/mmr.2018.8733. Epub 2018 Mar 14.
Pigment epithelial-derived factor (PEDF) is a multifunctional secreted glycoprotein, which exerts a variety of physiological activities. PEDF may protect against hypoxia‑induced cell death associated with its antioxidative effects and p53 mitochondrial translocation in cultured cardiomyocytes and H9c2 cells. Additionally, previous studies have suggested that autophagy is an important cell survival mechanism. However, the effect of PEDF on autophagy and the associated pathway in hypoxic H9c2 cells has not been fully established. Autophagy has been reported to regulate lipid metabolism; however, little is known about whether PEDF is able to regulate lipid metabolism by promoting autophagy. In the present study, western blotting results revealed that PEDF increased the level of microtubule‑associated protein 1A/1B‑light chain 3 (LC3)‑II. Transmission electron microscopy (TEM) and LC3 fluorescence demonstrated that PEDF increased the number of autophagosomes. PEDF also increased the viability of hypoxic H9c2 cells and decreased the level of cleaved caspase‑3 protein, as evidenced by CCK‑8 assays and western blotting, respectively. TEM and a triglyceride assay kit demonstrated that PEDF‑induced autophagy may stimulate lipid degradation. Western blotting results revealed a novel mechanism underlying PEDF‑induced H9c2 cell autophagy via the PEDF‑R‑mediated Atg5 pathway under hypoxic conditions. Furthermore, the results also suggest that PEDF‑induced autophagy may stimulate lipid degradation. The survival function of autophagy suggests that modulation of PEDF‑induced autophagy may be used as a therapeutic strategy to protect cells against lipid-associated metabolic diseases.
色素上皮衍生因子（PEDF）是一种多功能分泌糖蛋白，具有多种生理活性。PEDF 可通过其抗氧化作用和 p53 线粒体易位来保护培养的心肌细胞和 H9c2 细胞免受缺氧诱导的细胞死亡。此外，先前的研究表明自噬是一种重要的细胞存活机制。然而，PEDF 对缺氧 H9c2 细胞中自噬及其相关途径的影响尚未完全确定。自噬已被报道可调节脂质代谢；然而，尚不清楚 PEDF 是否能够通过促进自噬来调节脂质代谢。在本研究中，Western blot 结果显示 PEDF 增加了微管相关蛋白 1A/1B-轻链 3（LC3）-II 的水平。透射电子显微镜（TEM）和 LC3 荧光证实 PEDF 增加了自噬体的数量。PEDF 还通过 CCK-8 测定法和 Western blot 分别增加了缺氧 H9c2 细胞的活力并降低了 cleaved caspase-3 蛋白的水平。TEM 和甘油三酯测定试剂盒表明，PEDF 诱导的自噬可能刺激脂质降解。Western blot 结果显示，在缺氧条件下，PEDF 通过 PEDF-R 介导的 Atg5 途径诱导 H9c2 细胞自噬存在一种新的机制。此外，结果还表明 PEDF 诱导的自噬可能刺激脂质降解。自噬的存活功能表明，调节 PEDF 诱导的自噬可能被用作一种治疗策略，以保护细胞免受与脂质相关的代谢疾病的影响。
