Molecular correlation between mouse retina and striatum in HD

Huntington's disease (HD) is a devastating disorder caused by an aberrant expansion of CAG repeats in the HTT gene. Striatal dysfunction has been widely studied in HD mouse models as part of the basal ganglia, the main brain areas affected in patients that explain the most evident symptomatology. However, cumulative evidence indicates that the retina can also be functionally altered with consequences for visual function and circadian rhythms. Moreover, the retina is the most exposed part of the CNS that can be used for monitoring the health status of patients using non-invasive techniques and for treatment screenings in preclinical models. To establish the retina as an appropriate tissue for HD studies, it is first required to link retinal alterations at the cellular and molecular levels with those of the inner brain. In this work, we confirmed that the retinas of R6/1 mice were functionally and morphologically affected, and suffered a rearrangement of its transcriptome as extensive as in the striatum. Tissue-enriched genes were downregulated in both areas, but a neuroinflammation signature was specific to the R6/1 retina through the glial activation that was apparently absent in the striatum of the same animals. These phenomena were confirmed in the zQ175 strain, and were accompanied by a differential impairment of the autophagy system between both tissues that may have implications for autophagic-based therapies in HD. Overall, these results demonstrated the suitability of the retina as a research model for HD and general neurodegeneration. Overall design: Comparison of the gene expression profile in the retina and striatum of the same R6/1 and wild-type littermates.