Department of Anatomy, PTE-MTA Lendulet PACAP Research Team, University of Pecs, 7624 Pecs, Szigeti u 12, Hungary.
J Mol Neurosci. 2012 Nov;48(3):493-500. doi: 10.1007/s12031-012-9812-7. Epub 2012 May 29.
The integrity of retinal pigment epithelial cells is critical for photoreceptor survival and vision. Pituitary adenylate cyclase activating polypeptide (PACAP) exerts retinoprotective effects against several types of injuries in vivo, including optic nerve transection, retinal ischemia, excitotoxic injuries, UVA-induced lesion, and diabetic retinopathy. In a recent study, we have proven that PACAP is also protective in oxidative stress-induced injury in human pigment epithelial cells (ARPE-19 cells). The aim of the present study was to investigate the possible mechanisms of this protection. ARPE cells were exposed to a 24-h hydrogen peroxide treatment. Expressions of kinases and apoptotic markers were studied by complex array kits and Western blot. Oxidative stress induced the activation of several apoptotic markers, including Bad, Bax, HIF-1α, several heat shock proteins, TNF-related apoptosis-inducing ligand, and Fas-associated protein with death domain, while PACAP treatment decreased them. The changes in the expression of MAP kinases showed that PACAP activated the protective ERK1/2 and downstream CREB, and decreased the activation of the pro-apoptotic p38MAPK and c-Jun N-terminal kinase, an effect opposite to that observed with only oxidative stress. Furthermore, PACAP increased the activation of the protective Akt pathway. In addition, the effects of oxidative stress on several other signaling molecules were counteracted by PACAP treatment (Chk2, Yes, Lyn, paxillin, p53, PLC, STAT4, RSK). These play a role in cell death, cell cycle, inflammation, adhesion, differentiation and proliferation. In summary, PACAP, acting at several levels, influences the balance between pro- and anti-apoptotic factors in favor of anti-apoptosis, thereby providing protection in oxidative stress-induced injury of human retinal pigment epithelial cells.
视网膜色素上皮细胞的完整性对于光感受器的存活和视力至关重要。垂体腺苷酸环化酶激活肽（PACAP）在体内对多种损伤具有视网膜保护作用，包括视神经横断、视网膜缺血、兴奋性毒性损伤、UVA 诱导的损伤和糖尿病性视网膜病变。在最近的一项研究中，我们已经证明 PACAP 对人色素上皮细胞（ARPE-19 细胞）的氧化应激诱导损伤也具有保护作用。本研究旨在探讨这种保护作用的可能机制。ARPE 细胞暴露于 24 小时过氧化氢处理中。通过复杂的阵列试剂盒和 Western blot 研究激酶和凋亡标志物的表达。氧化应激诱导了几种凋亡标志物的激活，包括 Bad、Bax、HIF-1α、几种热休克蛋白、TNF 相关凋亡诱导配体和 Fas 相关死亡结构域蛋白，而 PACAP 处理则降低了它们的表达。MAP 激酶表达的变化表明，PACAP 激活了保护性的 ERK1/2 和下游 CREB，降低了促凋亡的 p38MAPK 和 c-Jun N-末端激酶的激活，这种作用与仅氧化应激观察到的作用相反。此外，PACAP 增加了保护性 Akt 途径的激活。此外，PACAP 处理还拮抗了氧化应激对几种其他信号分子的影响（Chk2、Yes、Lyn、paxillin、p53、PLC、STAT4、RSK）。这些分子在细胞死亡、细胞周期、炎症、黏附、分化和增殖中发挥作用。总之，PACAP 通过多种途径作用，影响细胞凋亡和抗细胞凋亡因子之间的平衡，有利于抗细胞凋亡，从而在人视网膜色素上皮细胞氧化应激诱导损伤中提供保护。
