Identifying Neuronal Signatures of Oxidative Stress via Small Extracellular Vesicle miRNA Profiling
Abstract
Background: Alzheimer’s Disease (AD) is a progressive neurodegenerative disorder that affects the aging population due to both environmental exposures and genetic risk factors. It is proposed that cell damage caused by oxidative stress contributes to the pathogenesis of AD. Evidence suggests that early alterations in AD-affected brains can propagate to local and distal cells through neuronal release of Extracellular Vesicles (EVs) which can cross the blood-brain barrier. These circulating EVs thus represent an easily accessible derivative of the brain in living humans. Exosomes, a type of small extracellular vesicle, contain various bioactive cargo including small, non-coding Ribonucleic Acids (RNAs) known as microRNAs (miRNA) that act as strong regulators of gene expression and can elicit effects in target cells. Here we aimed to experimentally identify candidate miRNAs that neuronal cells release in Small EVs (sEVs), such as exosomes, when under oxidative stress. Method: Sohin-Keeler Neuroblastoma Cell line, Medium Culture (SK-N-MC) cells were treated with Hydrogen Peroxide (H2 O2) to induce oxidative stress and miRNAs from both the SK-N-MC cells themselves as well as those contained in released sEVs were extracted and sequenced. Differentially expressed miRNAs were analyzed using Qiagen’s RNA-seq analysis portal and ingenuity pathway analysis. Results: We identified a miRNA profile indicative of H2 O2 exposure in neuronal sEVs–six miRNAs exhibited overrepresentation and two miRNAs exhibited underrepresentation with increasing H2 O2 treatment. Differentially expressed miRNAs were assayed with quantitative Polymerase Chain Reaction (PCR) in an independent experimental replication. Conclusion: These eight miRNAs are involved in many cellular processes, including regulation of Nuclear Factor Kappa B (NF-κB) complex associated genes and their related cellular responses. Their presence in sEVs from neurons may indicate the presence of oxidative stress and subsequently alter local and/or systemic responses.
