| Popis: |
An increase in the production of reactive oxygen species (ROS) and the inability of cellular machinery to adequately neutralize the ROS thus produced, lead the cells towards oxidative stress. ROS can damage all major classes of biomolecules including proteins, DNA and RNA. Recent findings show the evidence of high level of RNA oxidation in the neuronal cells of many neurological disorders suggesting a link between RNA oxidation and neurodegeneration. We have recently discovered the presence of extensive oxidative damage in the RNA molecules of neuronal cells in postmortem brains of multiple sclerosis (MS) patients.Working on the MS model system, we have established the identity of selectively oxidized mRNA molecules under MS microenvironment in human neuronal cells. Our study reveals that many of the mRNAs linked to various neurological pathways are selectively oxidized under oxidative stress. We have demonstrated the functional consequences of mRNA oxidation in two neuropathology related mRNAs (namely Nat8l and Nlrp3 mRNA). N-acetyl aspartate transferase 8 like protein (NAT8L) is a key trans-mitochondrial membrane protein that catalyzes the transfer of acetyl group from acetyl-CoA to aspartate to form N-acetyl aspartate (NAA) and transports NAA to neuronal cytoplasm. We have discovered that the oxidation in Nat8l mRNA molecule results in the reduced expression of NAT8L enzyme. We also observed a reduced level of NAA present in the neuronal cells under oxidative stress. Using the neuronal tissue culture and MS animal model (cuprizone mouse model), we have established that a higher mRNA oxidation results in a reduced expression of NAT8L protein, which presumably contributes to the MS disease progression by weakening the myelin production machinery. In a different context, we have also observed a unique situation where an oxidation in the Nlrp3 mRNA could lead towards the activation of alternative inflammasome pathway in human neurons under MS microenvironment. To the best of our knowledge, our study is the first to establish the direct connection between mRNA oxidation and MS neurodegeneration.In another study, we defined the impact of base oxidation in the structure and function of RNA molecules. We worked on an engineered version of the Tetrahymena group 1 intron (a ribozyme) to evaluate its enzymatic activity under oxidative stress. Our in vitro findings suggest the progressive loss of ribozyme function with increasing oxidation. Additionally, our investigation revealed that RNA oxidation is detrimental in RNA folding. We have also synthesized a novel 8-OHG analog (phosphorothioate) molecule with a potential to map the interference in the RNA structure due to the presence of oxidatively modified nucleosides. |
