2-ethylpyridine, a cigarette smoke component, causes mitochondrial damage in human retinal pigment epithelial cells in vitro

• Main Authors: S Mansoor, N Gupta, P Falatoonzadeh, B D Kuppermann, M C Kenney
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2014-01-01
• Series: Indian Journal of Ophthalmology
• Subjects: Lasik; corneal scars; corneoplastique; premium cataract surgery; refractive complications; radial keratotomy; pterygium; pinguecula; astigmatism; Antioxidants; electromagnetic ration; glutathione; lens; oxidative stress; 2-ethylpyridine; apoptosis; ARPE-19 cells; cigarette smoke toxicant; mitochondrial membrane potential; reactive oxygen/nitrogen species
• Online Access: http://www.ijo.in/article.asp?issn=0301-4738;year=2014;volume=62;issue=1;spage=16;epage=22;aulast=Mansoor

Purpose: Our goal was to identify the cellular and molecular effects of 2-ethylpyridine (2-EP, a component of cigarette smoke) on human retinal pigment epithelial cells (ARPE-19) in vitro. Materials and Methods: ARPE-19 cells were exposed to varying concentrations of 2-EP. Cell viability (CV) was measured by a trypan blue dye exclusion assay. Caspase-3/7 and caspase-9 activities were measured by fluorochrome assays. The production of reactive oxygen/nitrogen species (ROS/RNS) was detected with a 2′,7′-dichlorodihydrofluorescein diacetate dye assay. The JC-1 assay was used to measure mitochondrial membrane potential (ΔΨm). Mitochondrial redox potential was measured using a RedoxSensor Red kit and mitochondria were evaluated with Mitotracker dye. Results: After 2-EP exposure, ARPE-19 cells showed significantly decreased CV, increased caspase-3/7 and caspase-9 activities, elevated ROS/RNS levels, decreased ΔΨm value and decreased redox fluorescence when compared with control samples. Conclusions: These results show that 2-EP treatment induced cell death by caspase-dependent apoptosis associated with an oxidative stress and mitochondrial dysfunction. These data represent a possible mechanism by which smoking contributes to age-related macular degeneration and other retinal diseases and identify mitochondria as a target for future therapeutic interventions.