Oxidative RNA damage and neurodegeneration

Although cellular RNA should be subject to the same oxidative insults as DNA and other cellular macromolecules, oxidative damage to RNA has not been a major focus in investigating the magnitude and the biological consequences of the free radical damage. However, because RNA is mostly single-stranded and its bases are not protected by hydrogen bonding and are less protected by specific proteins, RNA may be more susceptible to oxidative insults than DNA. Thereafter, oxidative damage to protein-coding RNA or non-coding RNA will potentially cause errors in proteins or dysregulation of gene expression. While less lethal than mutations in genome, such non-acutely lethal insults to cells might be associated with underlying mechanisms of several human diseases, especially chronic degeneration. Recently, oxidative RNA damage has been described in several neurodegenerative diseases including Alzheimer disease, Parkinson disease, dementia with Lewy bodies, and prion diseases. Of particular interest, oxidative RNA damage is a feature in vulnerable neurons at the very earliest-stages of these diseases, suggesting that RNA oxidation may actively contribute to the onset or to the development of disease. Mechanistically speaking, an increasing body of evidence suggests that the detrimental effects of oxidative RNA damage to protein synthesis are attenuated, at least in part, by the existence of mechanisms that avoid the incorporation of the damaged ribonucleotides into the translational machinery. Further investigations toward understanding of the consequences and processing mechanisms related to oxidative RNA damage may provide significant insights into the pathogenesis and therapeutic strategies for neurodegenerative and other degenerative diseases.