Effect of palmitoylethanolamide on degeneration of a human-derived retinal pigment epithelial cell induced by all-trans retinal

AIM: To study the effect of palmitoylethanolamide(PEA) on apoptosis of retinal pigment epithelial(RPE) cells induced by all-trans retinal(at RAL) and to explore the possible molecular mechanism.METHODS: Cell Titer 96?Aqueous One Solution Cell Proliferation Assay(MTS) was used to detect the effect of PEA on human-derived retinal epithelial cells(ARPE-19) viability induced by at RAL. A Leica DMi8 inverted microscope was used to observe cell morphology. Reactive oxygen species(ROS) production was evaluated with 2’,7’-dichlorodihydrofluorescein diacetate(H2DCFDA) staining and fluorescence microscopy. Expression of c-Jun N-terminal kinase(JNK), phosphorylated JNK(p-JNK), c-Jun, phosphorylated c-Jun(p-c-Jun), Bak, cleaved caspase-3, C/EBP homologous protein(CHOP), and binding(Bip) protein levels were tested by Western blot. Abca4-/-Rdh8-/-mice, mouse models of at RAL clearance defects which displays some symbolic characteristics of dry age-related macular degeneration(AMD) and Stargardt disease(STGD1). In the animal models, PEA was injected intraperitoneally. The full-field electroretinogram was used to detect visual function under scotopic conditions traced from mice. Optical coherence tomography showed reconstitution or thickening of the retinal pigment epithelium layer. Effect of PEA on fundus injury induced by light in Abca4-/-Rdh8-/-mice was observed by fundus photography.RESULTS: PEA ameliorated ARPE-19 cells apoptosis and inhibited ROS(including mitochondrial ROS) production induced by at RAL. PEA improved the retinal functional, prohibited both RPE and photoreceptor from death, ameliorates light-induced fundus impairment in Abca4-/-Rdh8-/-mice. In vitro and in vivo, PEA inhibited JNK, p-JNK, c-Jun, p-c-Jun, Bak, cleaved caspase-3, CHOP, and Bip protein levels induced by all-trans retinal in ARPE-19 cells. CONCLUSION: PEA has effect on treating RPE cells apoptosis in retinopathy caused by at RAL accumulation. PEA is a potential treatment strategy for dry AMD and STGD1. The molecular mechanism is affecting the ROS-JNKCHOP signaling pathway partly.