| dc.description.abstract | The oxidative phosphorylation (OXPHOS) system, comprising five complexes, regulates electron transport and adenosine triphosphate (ATP) synthesis in mitochondria. Dysfunctions in these complexes lead to diverse diseases. Reactive oxygen species (ROS), as by-products of OXPHOS, contribute to cellular regulation but also stress, potentially causing oxidative damage and disease.
Investigating ROS-associated diseases requires robust model systems. Caenorhabditis elegans (C. elegans), due to its genetic manipulability and conserved mitochondrial functions, offers a promising platform. This study focuses on primary mitochondrial diseases, particularly deficiencies in OXPHOS, using C. elegans as an in vivo model to explore ROS formation and potential therapeutic interventions. Current research highlights the need for well-characterised models to study ROS in mitochondrial diseases especially in vivo. The study aimed to evaluate and elucidate the relationship between OXPHOS dysfunction and mitochondrial ROS in various C. elegans strains. Investigations using suitable models are crucial to advance our understanding of ROS-mediated pathologies and therapeutic strategies. Previous mouse models were used to investigate complex I knock out (KO), but experimental analyses are very time consuming, expensive and lacked conclusive evidence of ROS generation and oxidative stress markers.
Therefore, the aim of this study was the evaluation of ROS production in a selected number of OXPHOS KO stains of C. elegans. This involved thoroughly researching and identifying commercially available C. elegans strains with pathogenic variants in subunits of OXPHOS complexes. After acquiring these strains, which consisted of three for complex I (MQ1333, CW152 and LB25), one for complex II (TK22) and one for complex III (MQ887), as well as the wild type N2 strain and a putative ROS forming superoxide dismutase (SOD) knockout strain (GA184), the methods to maintain nematodes for research purposes were set up and their genotypes confirmed.
The last objective was to evaluate and compare the functional effects of the gene knockdowns using high resolution respirometry, locomotor activity and finally ROS production, respectively. For all the OXPHOS KO strains, except LB25 in respiration, there was a reduction in functionality of these phenotypic parameters. In line with other models of OXPHOS dysfunction, the strains showed significant variability between these parameters, with no clear pattern emerging. Considering the aim of this study, the complex I KO strain, CW152 was identified as the highest ROS-producing strain. These results provide a valuable comparison of functional effects related to OXPHOS dysfunction in five selected C. elegans strains. It could provide a springboard for
future investigations, particularly related to ROS production, on mitochondrial disease and therapeutic interventions. | en_US |
