Ameliorating Huntington’s disease
The hereditary disorder Huntington’s disease has so far been considered incurable. Its clinical manifestations include impaired motor control and psychiatric symptoms. A new study offers promising insights. It shows that a specific drug candidate called anle138b can significantly reduce the toxic protein clumps in the brain that are characteristic of the disease.
Affected mice that were administered this compound retained their mobility for a longer time, their brains shrank less, and their lifespan was extended compared to untreated mice. Importantly, the compound not only alleviates symptoms but also addresses the underlying cause of the disease by preventing disease-specific harmful protein clumps from destroying nerve cells and their connections. These results were also confirmed in experiments with human stem cells from Huntington’s patients.
These are the key findings of a study that has now been published in the journal EMBO Molecular Medicine.
“Our data show that specifically targeting toxic protein aggregates with the compound anle138b is a promising approach for stabilizing neuronal health in the long term,” the senior author.
Background: Huntington’s disease is an inherited movement disorder caused by a defect in a specific section of DNA, the gene that encodes the protein huntingtin. According to the health insurance organization AOK, approximately 10,000 people in Germany are affected by the disease. Several hundred new cases are diagnosed each year. A faulty repetition of the genetic code (known as CAG repeats) causes the huntingtin protein to take on an abnormal shape and form clumps.
The resulting protein aggregates can be thought of as a form of cellular waste that accumulates inside neurons. The protein aggregates disrupt vital cellular communication and lead to cell death, particularly in brain regions involved in for movement and cognition. An effective therapy that targets the underlying causes is not available. This is where the compound investigated anle138b comes into play, as it prevents the formation of the harmful structures.
The researchers investigated the efficacy of anle138b in two different mouse models: While one suffered from a severe, early-onset form of the disease, the other model mirrored the genetic situation in adult patients. The compound showed beneficial effects in both models.
A characteristic feature of Huntington’s disease is the loss of the protein PDE10A, which is found almost exclusively in the nerve cells that die in this disease. The amount of PDE10A decreases dramatically long before patients show the first severe symptoms. “If PDE10A levels drop, that is a clear signal that the disease is progressing. The protein is therefore well-suited as a biomarker for Huntington’s disease,” explains the lead author. If less nerve cells die, then the PDE10A levels stay high. This is exactly what the scientists observed: as a result of anle138b treatment, the concentration of PDE10A remained high in both mouse models.
A key milestone of the study is the confirmation of these effects in human cells. “In our experiments with induced pluripotent stem cells – that is, precursor cells derived from Huntington patients’ cells – we also observed that the addition of anle138b reduced the amount of huntingtin aggregates,” says the senior author.
Since the compound targets a fundamental mechanism of protein aggregation, it is also of interest for research on other neurodegenerative diseases. Corresponding studies in mouse models have been so promising that two years ago a large clinical trial was started for the treatment of multiple system atrophy – a Parkinson’s-like disorder characterized by severe impairments of motor function, balance, and the autonomic nervous system.
https://link.springer.com/article/10.1038/s44321-026-00459-9
