A New Approach to Gene Therapy: Targeting Mitochondrial DNA

In order to investigate the amount of mutant mitochondrial DNA after compound treatment, we had been analyzing mitochondrial DNA extracted from cells through quantitative PCR. However, the data varied greatly no matter how many times we tried. We were having trouble obtaining data that could be statistically analyzed and we realized that the alkylated mitochondrial DNA had been fragmented by heating during the PCR. When we analyzed the data after recovering from the alkylation, the decrease in mutant mitochondrial DNA, which had been buried due to the variability of the data, began to appear in a statistically significant form. Making one small realization and devising a plan we were able to overcome a hurdle that had been troubling us for months. I was very happy when I got the final piece of data for my paper.

Developing a compound that shows the targeted effect in living cells was a big challenge in itself. Because of the complex structure of cells, we must consider many possibilities. For instance, has the compound entered the cell or mitochondria, has it reacted with DNA or proteins other than the target, or has the compound degraded in the cell. We prioritized the factors which seemed to be particularly influential, and in the end, we found that the reactivity of the alkylating agent and the position of the mutant base relative to the compound were important. However, this took a long time, more than three years since the 2017 report on which this study is based (J. Am. Chem. Soc 2017, 139, 8444-8447). In fact, due to my degree application, I had come to the point where I thought, “If the next experiment doesn't work out, I am giving up on this research.” Fortunately, I was able to write a paper on another sub-theme, so I was able to complete this research without being bound by it. I think that working on the main theme for a long span of time and the sub-topic for a short span of time in parallel was very helpful in maintaining my motivation for the main theme.

There was a long period of no progress in this research, and I often wondered if I should continue with this theme. Whenever I stopped to think about whether to continue or not, as long as the possibility was not zero, I persevered taking small steps forward. I believe that this experience and the academic knowledge I gained in the process will help me grow as a researcher and will be a great support for my future research life.

I received my degree in March 2021, and now I am a JSPS Postdoctoral Fellow at RIKEN and a visiting researcher for iCeMS Taniguchi Lab, which has allowed me to continue to study at iCeMS. I am developing new methods for molecular and cellular biological analysis using microscopy and microfluidic technologies, which is a complete change from the chemical biology research I did while I was a student. I feel that it is only in the interdisciplinary research environment at iCeMS that I can experience such diverse fields of research within the same institute. As I am just beginning to shape my career, I would like to take advantage of this environment to foster my own science that is not limited by research fields and carry it with me to my future career.

*All the information on this page, including the researcher’s affiliation, is current at the time of the interview.