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Possible A2E Mutagenic Effects on RPE Mitochondrial DNA from Innovative RNA-Seq Bioinformatics Pipeline
Luigi Donato1,2, Concetta Scimone1,2, Simona Alibrandi1,3
1Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98125 Messina, Italy.
Abstract:
Mitochondria are subject to continuous oxidative stress stimuli that, over time, can impair their genome and lead to several pathologies, like retinal degenerations. Our main purpose was the identification of mtDNA variants that might be induced by intense oxidative stress determined by N-retinylidene-N-retinylethanolamine (A2E), together with molecular pathways involving the genes carrying them, possibly linked to retinal degeneration. We performed a variant analysis comparison between transcriptome profiles of human retinal pigment epithelial (RPE) cells exposed to A2E and untreated ones, hypothesizing that it might act as a mutagenic compound towards mtDNA. To optimize analysis, we proposed an integrated approach that foresaw the complementary use of the most recent algorithms applied to mtDNA data, characterized by a mixed output coming from several tools and databases. An increased number of variants emerged following treatment. Variants mainly occurred within mtDNA coding sequences, corresponding with either the polypeptide-encoding genes or the RNA. Time-dependent impairments foresaw the involvement of all oxidative phosphorylation complexes, suggesting a serious damage to adenosine triphosphate (ATP) biosynthesis, that can result in cell death. The obtained results could be incorporated into clinical diagnostic settings, as they are hypothesized to modulate the phenotypic expression of mtDNA pathogenic variants, drastically improving the field of precision molecular medicine.
Insights
Oxidative stress from A2E causes mitochondrial DNA variants, impacting ATP production and potentially leading to retinal degeneration. These findings aid precision medicine for mitochondrial diseases.
Area of Science:
- Mitochondrial biology
- Genetics
- Ophthalmology
Background:
- Mitochondria face constant oxidative stress, which can damage their DNA and contribute to diseases like retinal degeneration.
- N-retinylidene-N-retinylethanolamine (A2E) is implicated in oxidative stress within retinal cells.
Purpose of the Study:
- Identify mitochondrial DNA (mtDNA) variants induced by A2E-driven oxidative stress.
- Investigate molecular pathways associated with these variants in retinal degeneration.
- Explore A2E's potential mutagenic effects on mtDNA.
Main Methods:
- Comparative transcriptome analysis of A2E-treated and untreated human retinal pigment epithelial (RPE) cells.
- Integrated bioinformatic approach using multiple algorithms and databases for mtDNA variant analysis.
- Focus on variants within mtDNA coding sequences, including polypeptide-encoding genes and RNA.
Main Results:
- A significant increase in mtDNA variants was observed after A2E treatment.
- Variants were predominantly located in mtDNA coding regions, affecting genes for polypeptides and RNA.
- Time-dependent impairments affected all oxidative phosphorylation complexes, severely compromising adenosine triphosphate (ATP) biosynthesis.
Conclusions:
- A2E induces mtDNA variants and impairs mitochondrial function, potentially contributing to retinal pathologies.
- These findings can inform clinical diagnostics and enhance precision medicine for mtDNA-related disorders.
- Understanding A2E-induced mtDNA damage offers insights into the pathogenesis of retinal degenerations.
