Extracellular Vesicles Mediate Anti-Oxidative Response—In Vitro Study in the Ocular Drainage System

Abstract

The importance of extracellular vesicles (EVs) as signaling mediators has been emphasized for several pathways with only limited data regarding their role as protective messages during oxidative stress (OS). The ocular drainage system is unique by being continuously exposed to OS and having a one-way flow of the aqueous humor carrying EVs taking role in glaucoma disease. Here, we aimed to examine the ability of EVs derived from the non-pigmented ciliary epithelium (NPCE)—the aqueous humor producing cells exposed to OS—to deliver protecting messages to the trabecular meshwork (TM)—the aqueous humor draining cells—a process with significance to the pathophysiology of glaucoma disease. EVs extracted from media of NPCE cells exposed to non-lethal OS and their unstressed control were incubated with TM cells. The effects of EVs derived from oxidative stressed cells on the activation of the nuclear factor erythroid 2-related factor 2-Kelch-like ECH-associated protein 1 (Nrf2-Keap1), a major OS pathway, and of the Wnt pathway, known for its role in primary open-angle glaucoma, were evaluated. EVs derived from oxidized NPCE cells significantly protected TM cells from direct OS. The TM cells uptake of EVs from oxidized NPCE and their cytosolic Nrf2 levels were significantly higher at 8 h post-exposure. EVs derived from oxidized NPCE cells significantly attenuated Wnt protein expression in TM cells and activated major antioxidant genes as measured by qRT-PCR. TM cells exposed to EVs derived from oxidized NPCE cells exhibited significantly lower OS and higher super oxide dismutase and catalase activity. Finally, we were able to show that carbonylated proteins and products of oxidized protein are presented in significantly higher levels in EVs derived from oxidized NPCE cells, supporting their suggested role in the signaling process. We hypothesize that these findings may have implications beyond understanding the pathophysiology of glaucoma disease and that transmitting signals that activate the antioxidant system in target cells represent a broad response common to many tissues communication.

Juvenile Plasma Factors Improve Organ Function and Survival following Injury by Promoting Antioxidant Response

“…EVs regulate the activity of multiple physiological pathways, including the oxidative stress response, which is a hallmark of HI [ 31 , 32 ]. We tested MDA and hydrogen peroxide (H 2 O 2 ), two important oxidative stress markers in mice plasma.…”

Crosstalk between MicroRNA and Oxidative Stress in Primary Open-Angle Glaucoma

“…Furthermore, the possible involvement of oxidative damage to DNA in POAG pathogenesis may indicate that DNA mutations are involved in a variety of different human diseases with miRNA treatment as a potential therapeutic strategy that should be investigated. Recent studies emphasized the importance of extracellular vesicles, and specifically exosomes, as protective signaling mediators in TM cells during oxidative stress [ 166 ]. IL-1β-induced acute neuroinflammation and oxidative stress resulted in the release of a specific subset of miRNAs via exosomes, potentially regulating the inflammatory response [ 167 ].…”

Cannabidiol and the Canonical WNT/β-Catenin Pathway in Glaucoma

“…The aqueous humor outflow resistance is damaged by the change in adhesion junctions and cell contact, and then IOP is dysregulated [ 118 ]. The WNT/β-catenin pathway is believed to be a novel interventional target for the treatment of glaucoma [ 122 , 123 , 124 ]. Several WNT target genes are expressed in the TM, and the WNT ligand WNT3a is dysregulated [ 118 , 119 ].…”