Evaluation of an Antisense Oligonucleotide Targeting CAG Repeats: A Patient-Customized Therapy Study for Huntington’s Disease

Huntington's disease is a genetic disorder characterized by progressive neuronal cell damage in some areas of the brain; symptoms are commonly associated with chorea, rigidity and dystonia. The symptoms in Huntington's Disease are caused by a pathological increase in the number of Cytokine-Adenine-Guanine (CAG) repeats on the first exon of the Huntingtin gene, which causes a protein to have an excessive number of glutamine residues; this alteration leads to a change in the protein's conformation and function. Therefore, the purpose of this work was to design, synthesize and evaluate an antisense oligonucleotide (ASO; 95 nucleotides) HTT 90-5 directed to the Huntingtin CAG repeats in primary leukocyte culture cells from a patient with Huntington's Disease; approximately 500,000 leukocytes per well extracted from venous blood were used, to which 100 pMol of ASO were administered, and the expression of Huntingtin was subsequently evaluated at 72 h by RT-PCR. Our results showed that the administration of the HTT 90-5 antisense decreased the expression of Huntingtin mRNA in the primary culture leukocyte cells from our patient. These results suggest that the use of long antisense targeting the CAG Huntingtin cluster may be an option to decrease the expression of Huntingtin and probably could be adjusted depending on the number of CAG repeats in the cluster.