The current pharmacological treatment of Huntington’s disease (HD) is palliative, and therapies to restore functions in patients are needed. One of the pathways affected in HD involves brain cholesterol (Chol) synthesis, which is essential for optimal synaptic transmission. Given these bases, the presented thesis proposes three different mass spectrometric strategies to support the study of cholesterol involvement in HD.

Firstly, we evaluated nose-to-brain delivery as a non-invasive strategy to deliver Chol to the adult brain. We treated wild-type (WT) and R6/2 mice with intranasal (IN) doses of liposomes loaded with Chol in single and repeated doses trials. The results indicated the effectiveness of IN Chol-loaded liposomes to deliver Chol in different brain regions. In parallel, we investigated the levels of Chol metabolites in the brain after chronic IN treatment. The results highlighted a reduction in brain Chol synthesis, mostly involving the astrocytes, with a significant reduction of desmosterol levels in R6/2 mice. Moreover, the significantly lower levels of 24S-hydroxycholesterol in R6/2 mice with higher levels of desmosterol suggested the use of administered Chol to maintain the steady state of Chol synthesis in the whole brain. The analysis of Chol metabolites in plasma and brain samples from R6/2 mice showed how the reduction of Chol synthesis related to the disease was significant only at 12 weeks of age when the disease led definitely to death. Finally, we evaluated the distribution of Chol metabolites using imaging mass spectrometry (IMS). In conclusion, the presented thesis explored the study of HD, focusing on the development of different mass spectrometric strategies to study the pharmacokinetics of the administered Chol, the alteration of Chol metabolism, and the spatial distribution of Chol metabolites in brain slices of a mouse model of the disease. The proposed methods paved the way to further investigations on the alteration of brain Chol metabolism related to HD.