Abstract
A variety of pathophysiological mechanisms are implicated in Huntington's disease (HD). Among them, reduced cholesterol biosynthesis has been detected in the HD mouse brain from pre‐symptomatic stages, leading to diminished cholesterol synthesis, particularly in the striatum. In addition, systemic injection of cholesterol‐loaded brain‐permeable nanoparticles ameliorates synaptic and cognitive function in a transgenic mouse model of HD. To identify an appropriate treatment regimen and gain mechanistic insights into the beneficial activity of exogenous cholesterol in the HD brain, we employed osmotic mini‐pumps to infuse three escalating doses of cholesterol directly into the striatum of HD mice in a continuous and rate‐controlled manner. All tested doses prevented cognitive decline, while amelioration of disease‐related motor defects was dose‐dependent. In parallel, we found morphological and functional recovery of synaptic transmission involving both excitatory and inhibitory synapses of striatal medium spiny neurons. The treatment also enhanced endogenous cholesterol biosynthesis and clearance of mutant Huntingtin aggregates. These results indicate that cholesterol infusion to the striatum can exert a dose‐dependent, disease‐modifying effect and may be therapeutically relevant in HD.
Synopsis
The study shows that striatal infusion of cholesterol is able to improve behavioral, synaptic and neuropathological abnormalities in a mouse model of Huntington's disease.
Prevention of cognitive decline was achieved regardless of the dose of cholesterol infused in the striatum.
Motor defects were prevented in a dose‐dependent manner.
Synaptic transmission and morphology of striatal medium spiny neurons were normalized.
Endogenous cholesterol biosynthesis was stimulated in glial cells.
Mutant Huntingtin aggregates were decreased.
The study shows that striatal infusion of cholesterol is able to improve behavioral, synaptic and neuropathological abnormalities in a mouse model of Huntington's disease.