RESUMO
Endothelin-1 (ET-1) is a vasoactive peptide that is elevated in aqueous humor as well as circulation of primary open angle glaucoma (POAG) patients. ET-1 has been shown to promote degeneration of optic nerve axons and apoptosis of retinal ganglion cells (RGCs), however, the precise mechanisms are still largely unknown. In this study, RNA-seq analysis was used to assess changes in ET-1 mediated gene expression in primary RGCs, which revealed that 23 out of 156 differentially expressed genes (DEGs) had known or predicted mitochondrial function, of which oxidative phosphorylation emerged as the top-most enriched pathway. ET-1 treatment significantly decreased protein expression of key mitochondrial genes including cytochrome C oxidase copper chaperone (COX17) and ATP Synthase, H+ transporting, Mitochondrial Fo Complex (ATP5H) in primary RGCs and in vivo following intravitreal ET-1 injection in rats. A Seahorse ATP rate assay revealed a significant decrease in the rate of mitochondrial ATP production following ET-1 treatment. IOP elevation in Brown Norway rats showed a trend towards decreased expression of ATP5H. Our results demonstrate that ET-1 produced a decrease in expression of vital components of mitochondrial electron transport chain, which compromise bioenergetics and suggest a mechanism by which ET-1 promotes neurodegeneration of RGCs in glaucoma.
Assuntos
Endotelina-1/metabolismo , Glaucoma/metabolismo , Mitocôndrias/genética , Células Ganglionares da Retina/metabolismo , Animais , Proteínas de Transporte de Cobre/genética , Proteínas de Transporte de Cobre/metabolismo , Modelos Animais de Doenças , Endotelina-1/genética , Metabolismo Energético , Feminino , Expressão Gênica , Glaucoma/genética , Glaucoma/fisiopatologia , Humanos , Masculino , Mitocôndrias/metabolismo , ATPases Mitocondriais Próton-Translocadoras/genética , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Degeneração Neural , Ratos , Ratos Endogâmicos BNRESUMO
BACKGROUND: Various parts of Margaritaria discoidea find use in traditional medicine in the treatment of pain and oedema. This study evaluated the anti-allergic, anti-inflammatory and anti-arthritic effects of a 70% (v/v) aqueous ethanol extract of the stem bark of Margaritaria discoidea, MDE in rodents. MATERIALS AND METHODS: Systemic anaphylaxis was induced by the injection of compound 48/80 into mice and their survival rate was monitored to evaluate the anti-allergic action of the extract. The effect of MDE assessed on the maximal and total oedema responses in the mouse carrageenan-induced paw oedema was used to evaluate the anti-inflammatory action of the extract while the Freund's adjuvant-induced arthritis model was employed to study the anti-arthritic effects of MDE. RESULTS: MDE dose-dependently increased the time for compound 48/80-induced mortality in mice. MDE suppressed the mean maximal swelling and the total paw swellings induced over 6 h in the carrageenan-induced paw oedema when administered either prophylactically or therapeutically. MDE caused a reduction in serum levels of TNFα and IL-6 and significantly suppressed Freund's adjuvant-induced arthritis. CONCLUSION: Margaritaria discoidea suppresses allergy and exhibits anti-inflammatory activity in mice. In addition it attenuates Freund's adjuvant-induced arthritis through a reduction in serum levels of TNFα and IL-6 in rats.