A molecule called anle138b was able to reduce toxic alpha-synuclein aggregates, or clumps, in the brain — a key event linked to Parkinson’s — and reverse motor symptoms associated with the disease in a novel Parkinson’s mouse model.
The study, “Depopulation of dense α-synuclein aggregates is associated with rescue of dopamine neuron dysfunction and death in a new Parkinson’s disease model,” was published in Acta Neuropathologica. The work was funded by the charity Parkinson’s UK.
Many neurodegenerative disorders involve aggregation of misfolded (harmful) proteins in the brain. Parkinson’s is characterized by a buildup of the protein alpha-synuclein in the brain, which forms clumps known as Lewy bodies that damage and kill nerve cells, or neurons.
Investigators from the University of Cambridge now evaluated the effects of anle138b in a new mouse model of Parkinson’s disease.
Although this molecule had previously been shown to reduce the clumping of proteins in other Parkinson’s models, the team wanted to understand its potential to treat the condition during its natural progression. To that end, they created a new mouse model that mimics the way alpha-synuclein gradually accumulates in specific areas of the brain, impairing neuronal communication and resulting in motor alterations.
The animals were nine months old before treatment initiation — around 46 human years. At the start of the treatment, the mice already showed low levels of dopamine in their striatum, a brain region involved in voluntary movement control that is severely affected in Parkinson’s. This reduction was associated with the onset of motor symptoms, including changes in gait that resembled some of the early motor symptoms seen in individuals with the disease.
However, the animals’ substantia nigra, another brain region involved in motor function that is also affected by the disease, had not yet been significantly damaged. Mice striatal (meaning “of the striatum”) and nigral (meaning “of the substantia nigra“) dopamine-producing neurons also exhibited alpha-synuclein aggregation.
Starting at nine months of age, mice were treated with anle138b for three months. Treatment reduced alpha-synuclein clumps, restored dopamine levels in the brain, and prevented dopaminergic nerve cell death. This was accompanied by gait improvements, suggesting that anle138b can effectively reverse, or at least halt, Parkinson’s progression.
These results indicated that “there is a window of time when it is possible to prevent [dopaminergic] neuronal death, even when striatal [dopaminergic] release is already impaired,” the researchers said. This means that if anle138b is given early on — before advanced nerve cell death — it may reduce alpha-synuclein aggregates, potentially halting Parkinson’s progression.
“Our study demonstrates that by affecting early alpha-synuclein aggregation with the molecule anle138b in a novel transgenic mouse model, one can rescue the dopaminergic dysfunction and motor features that are typical of Parkinson’s,” Maria Grazia Spillantini, professor in the department of clinical neurosciences at the University of Cambridge, and the study’s lead researcher, said in a press release.
“The evidence from this early stage study builds on our understanding of how alpha-synuclein is involved in Parkinson’s and provides a new model that could unlock future treatments,” added Beckie Port, research manager at Parkinson’s UK.