The novel triterpenoid RTA 408 protects human retinal pigment epithelial cells against H2O2-induced cell injury via NF-E2-related factor 2 (Nrf2) activation

Autor: Jamieson Jann, Iok-Hou Pang, Hongli Wu, Christy Xavier, Keith W. Ward, Abbot F. Clark, Xiaobin Liu
Rok vydání: 2016
Předmět:
0301 basic medicine
viruses
Clinical Biochemistry
Retinal Pigment Epithelium
medicine.disease_cause
Biochemistry
chemistry.chemical_compound
Annexin
lcsh:QH301-705.5
bcl-2-Associated X Protein
lcsh:R5-920
Glutathione Disulfide
Caspase 3
Glutathione
Retinal pigment epithelial cells
Proto-Oncogene Proteins c-bcl-2
RNA Interference
lcsh:Medicine (General)
Oxidation-Reduction
Research Paper
Cell Survival
NF-E2-Related Factor 2
SOD2
Biology
Protective Agents
Nrf2
03 medical and health sciences
medicine
Humans
Viability assay
Propidium iodide
Cell damage
ComputingMethodologies_COMPUTERGRAPHICS
Organic Chemistry
Epithelial Cells
Hydrogen Peroxide
biochemical phenomena
metabolism
and nutrition
medicine.disease
Molecular biology
Triterpenes
030104 developmental biology
lcsh:Biology (General)
chemistry
Oxidative stress
Apoptosis
RTA 408
Reactive Oxygen Species
Zdroj: Redox Biology, Vol 8, Iss C, Pp 98-109 (2016)
Redox Biology
ISSN: 2213-2317
DOI: 10.1016/j.redox.2015.12.005
Popis: Graphical abstract
Oxidative stress-induced retinal pigment epithelial (RPE) cell damage is an important factor in the pathogenesis of age-related macular degeneration (AMD). Previous studies have shown that RTA 408, a synthetic triterpenoid compound, potently activates Nrf2. This study aimed to investigate the protective effects of RTA 408 in cultured RPE cells during oxidative stress and to determine the effects of RTA 408 on Nrf2 and its downstream target genes. Primary human RPE cells were pretreated with RTA 408 and then incubated in 200 μM H2O2 for 6 h. Cell viability was measured with the WST-8 assay. Apoptosis was quantitatively measured by annexin V/propidium iodide (PI) double staining and Hoechst 33342 fluorescent staining. Reduced (GSH) and oxidized glutathione (GSSG) were measured using colorimetric assays. Nrf2 activation and its downstream effects on phase II enzymes were examined by Western blot. Treatment of RPE cells with nanomolar ranges (10 and 100 nM) of RTA 408 markedly attenuated H2O2-induced viability loss and apoptosis. RTA 408 pretreatment significantly protected cells from oxidative stress-induced GSH loss, GSSG formation and decreased ROS production. RTA 408 activated Nrf2 and increased the expression of its downstream genes, such as HO-1, NQO1, SOD2, catalase, Grx1, and Trx1. Consequently, the enzyme activities of NQO1, Grx1, and Trx1 were fully protected by RTA 408 pretreatment under oxidative stress. Moreover, knockdown of Nrf2 by siRNA significantly reduced the cytoprotective effects of RTA 408. In conclusion, our data suggest that RTA 408 protect primary human RPE cells from oxidative stress-induced damage by activating Nrf2 and its downstream genes.
Highlights • Oxidative stress contributes to the pathogenesis of AMD. • RTA408 in nanomolar concentrations increased survival and restored the redox state in H2O2-damaged RPE cells. • RTA408 stimulated Nrf2 and downstream antioxidant enzymes Grx1, NQO1, and HO-1. • Inhibition of Nrf2 abolished RTA408’s protective effects. • RTA408 may have the potential to treat AMD and other degenerative eye diseases.
Databáze: OpenAIRE
Externí odkaz: