ABSTRACT

The mechanisms underlying detrimental effects of mutant huntingtin on striatal dysfunction in Huntington’s disease (HD) are not well understood. Although retinoic acid receptor beta (RARβ) emerged recently as one of the top regulators of transcriptionally downregulated genes in the striatum of HD patients and mouse models of HD its involvement in disease progression remains elusive. We report that genetically compromised RARβ signaling accelerates onset of motor abnormalities in R6/1 mouse model of HD. Transcriptional profiling revealed that downregulation of RARβ expression in Rarβ +/- ; R6/1 mice also accelerates transcriptional signature of disease progression by emergence of upregulated cluster of genes related to cell-cycle, stem cell maintenance and telencephalon development with concomitant downregulation of striatal cell-identity genes. The reactivation of proliferative activity demonstrated in the neurogenic niche and development-related transcriptional programs in the striatum prompt an attempt of lineage infidelity in HD striatum which may lead in consequence to disease-driving energy crisis as suggested by concomitant downregulation of transcripts essential for oxidative phosphorylation, a well-accepted correlate of HD physiopathology, and a metabolic change required for maintenance of proliferative activity and differentiation but not compatible with high energetic demand of differentiated and active neurons.

Highlights

Compromising RARβ expression in R6/1 mouse model of HD accelerates onset of HD-like motor abnormalities Compromised RARβ signaling contributes to the progression of disease-related transcriptional changes in R6/1 mice RARβ supports cell-identity maintenance in HD mouse model