The genetic code consists of the letters A, T, G and C. Some neurodegenerative conditions are caused by the letters C, A and G repeating many times over. These conditions are collectively called polyglutamine disorders, and they include SCA1, SCA2, SCA3, SCA6, SCA7, SCA17 and dentatorubral-pallidoluysian atrophy (DRPLA).
Genes contain instructions for how to make proteins. The CAG repeat found in polyglutamine ataxias causes the protein under production to contain a chain of an amino acid called glutamine. This chain of glutamine causes the protein to fold incorrectly, and it becomes very sticky. The protein then sticks to other similar proteins, causing them to clump together. These protein clumps are what causes the cell death, which leads to the symptoms of ataxia. Researchers believe that if they could identify a treatment that targets the chain of glutamine, they could slow progression of all these different types of ataxia.
With this idea in mind, researchers in Japan began looking for a drug which could target the glutamine chain and prevent the protein clumps from forming.
In their study they showed that a compound called Arginine was able to prevent the protein clumps from forming in cell models of polyglutamine disorders. They also showed that arginine was able to improve neurological symptoms in a number of animal models of polyglutamine disorders.
Arginine has been used to treat other conditions, so this could be a promising candidate for drug-repurposing in the clinic.
Please note that this study shows results in cell and animal models only. Arginine has not been tested in the appropriate clinical trials for people with ataxia, which are necessary to determine both the efficacy and the safety of taking arginine to treat ataxia.
Read the article abstract here.
Posted on 22/06/2020