Phosphoproteomic dysregulation in Huntington’s disease mice is rescued by environmental enrichment

Abstract

Huntington’s disease is a fatal autosomal dominant neurodegenerative disorder, characterized by neuronal cell loss, primarily in the striatum, cortex, and hippocampus, causing motor, cognitive, and psychiatric impairments. Unfortunately, no treatments are yet available to modify the progression of the disease. Recent evidence from Huntington’s disease mouse models suggests that protein phosphorylation (catalysed by kinases and hydrolysed by phosphatases) might be dysregulated, making this major posttranslational modification a potential area of interest to find novel therapeutic targets. Furthermore, environmental enrichment, used to model an active lifestyle in preclinical models, has been shown to alleviate Huntington’s disease-related motor and cognitive symptoms. However, the molecular mechanisms leading to these therapeutic effects are still largely unknown. In this study, we applied a phosphoproteomics approach combined with proteomic analyses on brain samples from pre-motor symptomatic R6/1 Huntington’s disease male mice and their wild-type littermates, after being housed either in environmental enrichment conditions, or in standard housing conditions from 4 to 8 weeks of age (n = 6 per group). We hypothesised that protein-phosphorylation dysregulations occur prior to motor onset in this mouse model, in two highly affected brain regions, the striatum and hippocampus. Furthermore, we hypothesised that these phosphoproteome alterations are rescued by environmental enrichment. When comparing 8-week-old Huntington’s disease mice and wild-type mice in standard housing conditions, our analysis revealed 229 differentially phosphorylated peptides in the striatum, compared to only 15 differentially phosphorylated peptides in the hippocampus (statistical thresholds fold discovery rate 0.05, fold change 1.5). At the same disease stage, minor differences were found in protein levels, with 24 and 22 proteins dysregulated in the striatum and hippocampus, respectively. Notably, we found no differences in striatal protein phosphorylation and protein expression when comparing Huntington’s disease mice and their wild-type littermates in enriched conditions. In the hippocampus, only four peptides were differentially phosphorylated between the two genotypes under enriched conditions, and 22 proteins were differentially expressed. Together, our data indicates that protein phosphorylation dysregulations occur in the striatum of Huntington’s disease mice, prior to motor symptoms, and that the kinases and phosphatases leading to these changes in protein phosphorylation might be viable drug targets to consider for this disorder. Furthermore, we show that an early environmental intervention was able to rescue the changes observed in protein expression and phosphorylation in the striatum of Huntington’s disease mice and might underlie the beneficial effects of environmental enrichment, thus identifying novel therapeutic targets.

Targeting the ribosome to treat multiple myeloma

“…Dynamic exclusion was activated for 30 s. All the studies were conducted at the Mass Spectrometry and Proteomics Facility, Bio21 Molecular Science and Biotechnology Institute, Melbourne, Australia as previously described. 59 …”

Phosphoproteomics implicates glutamatergic and dopaminergic signalling in the antidepressant-like properties of the iron chelator deferiprone

“…Inc, LA Jolla, USA). Size of treatment group numbers were based on prior studies (n=4-6) for a total of 21 samples (Mees, Li, et al, 2022; Mees, Tran, et al, 2022; Xiao et al, 2020).…”

“…We then performed two sample T-tests and significant changes were defined as p<0.01 and, Fold change of 1.5. Size of treatment group numbers were based on prior studies (n=5-6) for a total of 23 samples (Mees, Li, et al, 2022; Mees, Tran, et al, 2022; Xiao et al, 2020). Code for phosphoproteomics and global proteomics analysis can be found at https://github.com/vuzungil01/dfp_phosphoproteomics.…”

“…Phosphorylation or dephosphorylation is a protein post-translational modification event which can be used as an indirect maker of protein activity or inactivity (Ramazi & Zahiri, 2021). Our lab has previously demonstrated a reversal of phosphoproteomic dysregulation in Huntington’s disease mice following environmental enrichment (Mees, Li, et al, 2022). There is evidence that patients with MDD have an altered phosphoproteome, with synaptic proteins being implicated in the differential expression profile (Martins-de-Souza et al, 2012).…”

Targeting the ribosome to treat multiple myeloma

“…Peptide mixtures were analyzed by nanoLC-MS/MS using the Q Exactive Plus Orbitrap Mass Spectrometer (Thermo Scientific) for proteomics analysis and the Orbitrap Exploris 480 mass spectrometer (Thermo Scientific) for phosphoproteomics analysis. All the studies were conducted at the Mass Spectrometry and Proteomics Facility, Bio21 Molecular Science and Biotechnology Institute, Melbourne, Australia as previously described (27) Raw files were processed using MaxQuant (version 2.0.3.0) (28). The processed data was analyzed with Perseus (version 1.6.15.0).…”