Aloe-emodin metabolites protected N-methyl-d-aspartate-treated retinal ganglion cells by Cu-Zn superoxide dismutase.
A high concentration of glutamate in the eyes not only activates N-methyl-D-aspartate (NMDA) receptors, but also is toxic to the retina ganglion cells (RGCs) in glaucomatous patients. Our previous study had found that aloe-emodin sulfates/glucuronides metabolites, an anthraquinone polyphenol, exerted a neuroprotective activity upon RGCs. In order to understand the mechanisms involved in this neuroprotective effect, this study aimed to determine the expressions of RNAs and proteins in various treatments. The proteins expressed in the control group, NMDA-treated group, and aloe-emodin metabolites-cotreated group were separated by two-dimensional gel electrophoresis (2-DE). Protein spots were excised from 2-DE and analyzed by nano-LC-MS/MS (nano-liquid chromatography with mass spectrometry; tandem MS). Quantitative polymerase chain reaction (Q-PCR) was used to investigate the RNA related to these proteins. There were 84 spots with significant differences in various treatments. Among the 84 spots, we identified 9 spots whose functions were closely related to regulate the apoptosis of cells. The results of Q-PCR were not completely unanimous with those of 2-DE. Our results suggested that aloe-emodin metabolites decreased NMDA-induced apoptosis of RGCs by preserving, and inducing, some proteins related to the antioxidation and regulation of cells' energy. Both the level of RNA and protein of superoxide dismutase (Cu-Zn) were significantly elevated after aloe-emodin metabolites were added. The mechanisms of neuroprotection are complicated, and involve not only the transcription and stability of mRNA, but also post-translation protein modifications, degradation, and protein-protein interaction.
Lin
Hui-Ju
HJ
Department of Ophthalmology, China Medical University Hospital, Asia University, Taichung, Taiwan.
Lai
Chien-Chen
CC
Lee Chao
Pei-Dawn
PD
Fan
Seng-Sheen
SS
Tsai
Yuhsin
Y
Huang
Shiuan-Yi
SY
Wan
Lei
L
Tsai
Fuu-Jen
FJ
D000818:Animals; D000880:Anthraquinones; D017209:Apoptosis / Q000187:drug effects; D002853:Chromatography, Liquid; D015180:Electrophoresis, Gel, Two-Dimensional; D004642:Emodin / Q000378:metabolism* / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000378:metabolism; D005786:Gene Expression Regulation; D005901:Glaucoma; D020719:Glucuronides / Q000494:pharmacology*; D018698:Glutamic Acid; D016202:N-Methylaspartate / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000187:drug effects* / Q000378:metabolism; D021241:Spectrometry, Mass, Electrospray Ionization; D013431:Sulfates / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000378:metabolism; D014158:Transcription, Genetic
D000880:Anthraquinones; D004791:Enzyme Inhibitors; D020719:Glucuronides; D018696:Neuroprotective Agents; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D013431:Sulfates; D018698:Glutamic Acid; D016202:N-Methylaspartate; C518327:aloe emodin; D013482:Superoxide Dismutase; D004642:Emodin