Cheng Huan-Huan, Ye Hui, Peng Rui-Ping, Deng Juan, Ding Yong
Department of Ophthalmology, the Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, China.
Department of Ophthalmology, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China.
Neural Regen Res. 2018 May;13(5):923-929. doi: 10.4103/1673-5374.232489.
Pituitary adenylate cyclase-activating polypeptide (PACAP) is an endogenous peptide with neuroprotective effects on retinal neurons, but the precise mechanism underlying these effects remains unknown. Considering the abundance of mitochondria in retinal ganglion cells (RGCs), we postulate that the protective effect of PACAP is associated with the regulation of mitochondrial function. RGC-5 cells were subjected to serum deprivation for 48 hours to induce apoptosis in the presence or absence of 100 nM PACAP. As revealed with the Cell Counting Kit-8 assay, PACAP at different concentrations significantly increased the viability of RGC-5 cells. PACAP also inhibited the excessive generation of reactive oxygen species in RGC-5 cells subjected to serum deprivation. We also showed by flow cytometry that PACAP inhibited serum deprivation-induced apoptosis in RGC-5 cells. The proportions of apoptotic cells and cells with mitochondria depolarization were significantly decreased with PACAP treatment. Western blot assays demonstrated that PACAP increased the levels of Bcl-2 and inhibited the compensatory increase of PAC1. Together, these data indicate protective effects of PACAP against serum deprivation-induced apoptosis in RGCs, and that the mechanism of this action is associated with maintaining mitochondrial function.
垂体腺苷酸环化酶激活多肽（PACAP）是一种对视网膜神经元具有神经保护作用的内源性肽，但其作用的确切机制尚不清楚。鉴于视网膜神经节细胞（RGCs）中存在大量线粒体，我们推测PACAP的保护作用与线粒体功能的调节有关。在有或无100 nM PACAP存在的情况下，将RGC-5细胞进行48小时血清剥夺以诱导凋亡。如细胞计数试剂盒-8检测所示，不同浓度的PACAP显著提高了RGC-5细胞的活力。PACAP还抑制了血清剥夺的RGC-5细胞中活性氧的过量产生。我们还通过流式细胞术表明，PACAP抑制了血清剥夺诱导的RGC-5细胞凋亡。经PACAP处理后，凋亡细胞和线粒体去极化细胞的比例显著降低。蛋白质免疫印迹分析表明，PACAP增加了Bcl-2的水平并抑制了PAC1的代偿性增加。这些数据共同表明，PACAP对血清剥夺诱导的RGCs凋亡具有保护作用，且这种作用机制与维持线粒体功能有关。
