A group of researchers develops a potential drug to treat myotonic dystrophy type 1: cugamycin
Researchers at the Gripps Research Institute in Florida (United States) have published an article in the Proceedings of the National Academy of Sciences in which they show the therapeutic capacity of a new compound, cugamycin, in cells of patients with myotonic dystrophy type 1 and in a mouse model of the disease. In both systems, it is observed that gene expression patterns return to normal thanks to cugamycin and that cugamycin improves disease symptoms in mice by 98%.
Myotonic dystrophy type 1 (DM1) or Steinert's disease is a congenital neuromuscular disease characterised by the presence of myotonia – prolonged contraction of the muscles and great difficulty in relaxing them afterwards – and multiorgan damage. DM1 affects about one in 8,000 people and is caused by the abnormal repetition of a DNA fragment in the DMPK gene: healthy people usually show 5-34 CTG codon repeats in that gene but those affected by DM1 have many more repeats, between 50 and 4,000. This prevents the gene from being transcribed into RNA in the correct way and the resulting proteins are defective, making it impossible for the muscle cell to function properly.
In their recent work, the team of Dr Matthew D. Disney develops a small molecule, formed by an area that binds to the altered RNA and a cytotoxic agent that cuts nucleic acids, which recognizes the structure formed by the repetitions in the RNA and the fragment. To date, other approaches have been used to curb myotonic dystrophy, such as antisense oligonucleotides, which do not discriminate whether the repeats correspond to a healthy RNA fragment or to a fragment with repetition expansions, which resulted in many undesirable effects.
According to the authors, although no hasty conclusions should be drawn due to the preliminary nature of the results, the work suggests the existence of a potential treatment for DM1 and other diseases produced by similar genetic causes, such as amyotrophic lateral sclerosis or Huntington's disease.
Access to the original article: Precise small-molecule cleavage of an r(CUG) repeat expansion in a myotonic dystrophy mouse model. Proceedings of the National Academy of Sciences.