Cardiovascular Exercise Drives Neuroprotection in a Mouse Model of Spinocerebellar Ataxia 1 Via Rescue of Aberrant Splicing

Objective Spinocerebellar ataxia 1 (SCA1) is a fatal hereditary neurodegenerative disorder with no approved therapies, and gene‐targeting strategies have thus far failed in clinical trials. Exercise remains the only intervention shown to provide clinical benefit in patients with spinocerebellar ataxias (SCAs), yet the underlying mechanisms remain poorly understood. Methods Using the Atxn1 154Q/2Q knock‐in mouse model, we implemented a prolonged voluntary wheel‐running paradigm from 4 to 16 weeks of age. Mice were then phenotyped using motor and cognitive behavioral assays. Following euthanasia, cerebellar tissue was harvested for histological analysis and unbiased transcriptomics. Results Unrestricted exercise rescued motor ataxia but not degeneration in this SCA1 mouse model at the ages in this study. Transcriptional profiling of cerebellar tissue separated wild‐type (WT) sedentary and exercise mice by differential gene expression, but in SCA1 mice the most pronounced changes occurred at the level of RNA splicing, particularly in ion channel modules. Exercise led to a significant rescue of splicing events in SCA1 mice, with minimal impact on gene expression changes. Further, both exercised SCA1 and WT mice exhibited splicing patterns more similar to each other than their sedentary counterparts. Interpretation Together with emerging evidence in other SCAs, our findings confirm aberrant splicing as a central driver of SCA pathophysiology and identify splicing‐regulated networks as actionable therapeutic targets. The observed benefits in SCA1 mice suggest that correcting mis‐spliced ion channels may be a viable strategy for disease modification across SCAs and related neurodegenerative disorders. ANN NEUROL 2026