Mitochondria are cellular organelles that participate in many key processes in our organism, including ATP production to provide the cells with energy, regulation of metabolism, and signaling. Mitochondria are unique organelles because they possess their own DNA, independent from the DNA in the cell nucleus, and mitochondrial function is thus regulated jointly by both genomes. It is now widely recognized that mitochondria are crucially important in immune responses, although the exact roles of mitochondria are cell type specific, complex, and not always clearly understood.
In her doctoral dissertation, MSc Yuliya Basikhina investigated the role of mitochondria in innate immunity, as well as the effect of genetic variation on immune responses. As a model, she utilized the fruit fly Drosophila melanogaster, a well-established model species which has been used extensively both in the field of immunology and mitochondrial biology.
“While the fly is obviously not equivalent to a human, there is a high level of similarity between human and Drosophila genes involved in the innate immune responses and mitochondrial metabolic pathways. This makes the data obtained in fly studies relevant and suitable for further validation in a mammalian model system”, Basikhina says.
The results show, in line with other previously published research in the field, that mitochondrial involvement in immunity is highly tissue specific. Utilizing the molecular genetics approaches for manipulating the gene expression in the fly, Basikhina was able to show that silencing mitochondrial genes results in opposing effects depending on the target immune tissue. The mild mitochondrial dysfunction caused by the gene silencing boosted the cellular immune responses but was detrimental when the humoral immune tissue of the fly was targeted.
In addition, the data shows that on the organismal level, the genetic variation originating from either the nuclear or the mitochondrial genome can have a significant impact on infection outcomes. This needs to be taken into account, for instance, when developing therapies for infectious diseases. It is particularly relevant for personalized medicine, where the individual’s specific mutations and gene variants may affect disease progression, as well as responses to the treatment.
“My research shows that different pathogens affect the host in distinct ways. The omics approaches used in this study reveal that some bacteria and viruses are capable of silencing mitochondria, likely as a part of virulence strategy to ensure survival inside the host. Taken together, these findings provide a foundation for future research, where the mitochondrial involvement in innate immunity and the contribution of genetic variation to immune response efficiency can be studied in more detail, and the resulting knowledge could be possibly applied in medicine”, Basikhina concludes.
Public defence on Friday 10 October
The doctoral dissertation of MSc Yuliya Basikhina in the field of biosciences titled The Powerhouse of Immunity: Mitochondrial metabolism in innate immune responses will be publicly examined at the Faculty of Medicine and Health Technology at Tampere University on 10 October 2025. The Opponent will be Professor Petros Ligoxygakis, University of Oxford. The Custos will be Docent Tiina Salminen from the Faculty of Medicine and Health Technology, Tampere University.