The Role of Extracellular Vesicles in Optic Nerve Injury: Neuroprotection and Mitochondrial Homeostasis

Abstract

Stem cell therapies hold great promise as alternative treatments for incurable optic nerve disorders. Although mesenchymal stem cells exhibit various tissue regeneration and recovery capabilities that may serve as valuable therapies, the clinical applications remain limited. Thus, we investigated the utility of extracellular vesicles (EVs) from human placenta-derived mesenchymal stem cells (hPSCs) in this context. Hypoxically preconditioned hPSCs (HPPSCs) were prepared via short-term incubation under 2.2% O2 and 5.5% CO2. The EVs were then isolated. R28 cells (retinal precursor cells) were exposed to CoCl2 and treated with EVs for 24 h. Cell proliferation and regeneration were measured using a BrdU assay and immunoblotting; ATP quantification revealed the extent of the mitochondrial function. The proteome was determined via liquid chromatography-tandem mass spectroscopy. Differentially expressed proteins (DEPs) were detected and their interactions identified. HPPSC_EVs functions were explored using animal models of optic nerve compression. HPPSC_EVs restored cell proliferation and mitochondrial quality control in R28 cells damaged by CoCl2. We identified DEPs (p < 0.05) that aided recovery. The mitochondrial DEPs included LONP1; PARK7; VDAC1, 2, and 3; HSPD1; and HSPA9. EVs regulated the levels of mitophagic proteins in R28 cells injured by hypoxia; the protein levels did not increase in LONP1 knockdown cells. LONP1 is a key mediator of the mitophagy that restores mitochondrial function after hypoxia-induced optic nerve injury.

Proteomic Profiling of Mesenchymal Stem Cell-Derived Extracellular Vesicles: Impact of Isolation Methods on Protein Cargo

“…Therefore, the application of EVs isolated through either high-speed centrifugation or ultracentrifugation may exhibit therapeutic effects, given that both small and large EVs have shown therapeutic potential in existing literature. (Dave et al, 2023; Ikeda et al, 2021; Park et al, 2022; Silva et al, 2021). Therefore, considering the proteome content of EV subpopulations could enhance their therapeutic application.…”

“…Consequently, there has been a significant focus on intervention approaches aimed at targeting mitochondria as potential therapeutic options for these debilitating diseases. Notably, the beneficial effects of EVs derived from MSCs in improving mitochondrial function have made EVs an intriguing target in this regard (Park, Shin, Duong, Lee, & Lew, 2022; Silva et al, 2021; Zhao et al, 2020). Comparing the beneficial effects of mitovesicles, which specifically carry mitochondrial proteins, with various EV subpopulations that not only contain several mitochondrial proteins but also include proteins related to the anti-inflammatory pathway, is indeed interesting for future studies.…”

Cell Type-Specific Extracellular Vesicles and Their Impact on Health and Disease

“…In the context of glaucoma, recent studies have been investigating the role of CTS-EVs in intraocular pressure regulation and optic nerve damage [ 151 ]. Research demonstrates that CTS-EVs play a role in the pathology of glaucoma, particularly in the regulation of intraocular pressure and signaling within the ocular system.…”

Mesenchymal stem cells for repairing glaucomatous optic nerve

“…MSC may improve mitochondrial function and attenuate oxidative damage by inhibiting reactive oxygen species (ROS) production and enhancing mitochondrial dynamics. Hypoxic preconditioning appears to enhance the therapeutic effects of MSC in neurological disorders and traumatic injuries [23] . Platelet-derived growth factor (PDGF) secretion may play an important role in MSC-mediated neuroprotection of RGCs, and may be an independent target for achieving neuroprotection of RGCs.…”