Interrogation of brain miRNA and mRNA expression profiles reveals a molecular regulatory network that is perturbed by mutant huntingtin.

Emerging evidence indicates that microRNAs (miRNAs) may play an important role in the pathogenesis of Huntington's disease (HD). To identify the individual miRNAs that are altered in HD and may therefore regulate a gene network underlying mutant huntingtin-induced neuronal dysfunction in HD, we performed miRNA array analysis combined with mRNA profiling in the cerebral cortex from N171-82Q HD mice. Expression profiles of miRNAs as well as mRNAs in HD mouse cerebral cortex were analyzed and confirmed at different stages of disease progression; the most significant changes of miRNAs in the cerebral cortex were also detected in the striatum of HD mice. Our results revealed a significant alteration of miR-200 family members, miR-200a, and miR-200c in the cerebral cortex and the striatum, at the early stage of disease progression in N171-82Q HD mice. We used a coordinated approach to integrate miRNA and mRNA profiling, and applied bioinformatics to predict a target gene network potentially regulated by these significantly altered miRNAs that might be involved in HD disease progression. Interestingly, miR-200a and miR-200c are predicted to target genes regulating synaptic function, neurodevelopment, and neuronal survival. Our results suggest that altered expression of miR-200a and miR-200c may interrupt the production of proteins involved in neuronal plasticity and survival, and further investigation of the involvement of perturbed miRNA expression in HD pathogenesis is warranted, and may lead to reveal novel approaches for HD therapy.