Causes of rare genetic diseases such as Huntington\'s chorea include not only damaged protein, but also RNA - according to a study at the Institute of Bioorganic Chemistry PAS in Poznań. Scientists at the institute want to understand the mechanisms responsible for the development of such diseases.
Polyglutamine diseases are a group of incurable rare genetic diseases that lead to brain cell death. One of the most common of them is Huntington\'s disease. It usually affects people at the age of 35-50, although few years old children may suffer from it as well. The disease not only exacerbates the quality of life, but also shortens it by 20 years. It is manifested by involuntary, uncoordinated, jerky body movements, progressive dementia and cognitive disorders. It often leads to death.
Huntington\'s disease is caused by mutation in a particular gene. A healthy person has up to 26 repetitions of three nucleotides - CAG, which correspond to the amino acid - glutamine, used in the biosynthesis of proteins. In people with Huntington\'s disease, the number of CAG repeats exceeds 40.
Information stored in the gene is transcribed into gene products - RNA and protein. First, the transcription process results in an mRNA that retains information about the increased number of CAG repeats. The final translation of genetic information into a specific protein structure occurs in the translation process. The protein also retains information about the elongated CAG sequence. RNA and protein derived from the gene are toxic to the cell and disrupt its processes. Eventually, this leads to cell death, which is particularly noticeable in the nervous system.
According to researchers from the Institute of Bioorganic Chemistry PAS, finding an agent that would stop or delay the course of polyglutamine diseases is difficult for several reasons. One of the problems is the genetic background of the disease. Scientists are not yet able to effectively "repair" genes in all cells of adult organisms. The disease primarily affects the nervous system, the accessibility of which to drugs is limited by the presence of a physical barrier separating blood from the brain. There would a need for direct dosage of drugs into the brain, which is very dangerous.
While researchers can name and locate genes responsible for rare polyglutamine diseases, they still have not learned the mechanisms of their formation. This task has been undertaken by a research team from the Institute of Bioorganic Chemistry of the Polish Academy of Sciences in Poznań. Martyna Urbanek, L\'Oréal Polska for Women and Science scholarship holder who participates in the project, is working on "nucleic RNA concentrations in cellular models of polyglutamine diseases".
"By studying single cells, I explain how genetic diseases form and what tools should be used to effectively fight them. Modern medicine only allows to relieve the symptoms of genetic diseases that I study. I want my findings to lead to finding a way to effectively combat them with a new therapeutic approach" - explained Urbanek.
"My research shows that the product of damaged gene - RNA - plays a role in the pathogenesis of polyglutamine diseases, inter alia by the formation of RNA clusters. This shows that proposed therapy should take both gene products - RNA and protein - into account, and not just the damaged protein, as previously proposed. By removing only the damaged protein, we would remove only a part of the cause of the disease, and thus only some of the symptoms. My work also includes the possibility of removal of RNA clusters, which could be an element of therapy" - said Martyna Urbanek.
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