Glioblastoma (GB) is the most aggressive form of glioma and is characterized by poor prognosis and high recurrence despite intensive clinical interventions. To retrieve the key factors underlying the high malignancy of GB with potential diagnosis utility, we combined the analysis of The Cancer Gene Atlas and the REMBRANDT datasets plus a molecular examination of our own collection of surgical tumor resections. We determined a net reduction in the levels of the non-canonical histone H3 variant H3.3 in GB compared to lower-grade astrocytomas and oligodendrogliomas with a concomitant increase in the levels of the canonical histone H3 variants H3.1/H3.2. This increase can be potentially useful in the clinical diagnosis of high-grade gliomas, as evidenced by an immunohistochemistry screening of our cohort and can be at least partially explained by the induction of multiple histone genes encoding these canonical forms. Moreover, GBs showing low bulk levels of the H3.1/H3.2 proteins were more transcriptionally similar to low-grade gliomas than GBs showing high levels of H3.1/H3.2. In conclusion, this study identifies an imbalanced ratio between the H3 variants associated with glioma malignancy and molecular patterns relevant to the biology of gliomas, and proposes the examination of the H3.3 and H3.1/H3.2 levels to further refine diagnosis of low- and high-grade gliomas in future studies.

Huntington’s disease (HD) is a devastating disorder caused by aberrant expansion of CAG repeats in the HTT gene. Striatal dysfunction has been widely studied in HD mouse models. However, cumulative evidence indicates that the retina can also be functionally altered with consequences for visual function and circadian rhythms. The retina is the most exposed part of the central nervous system that can be used for monitoring the health status of patients using noninvasive techniques. To establish the retina as an appropriate tissue for HD studies, we linked the retinal alterations with those in the inner brain. We confirmed the malfunction of the R6/1 retinas, which underwent a rearrangement of their transcriptome as extensive as in the striatum, indicating a profound retinal affectation in HD. Tissue-enriched genes were downregulated in both areas, but a neuroinflammation signature was specifically induced in the R6/1 retina due to glial activation that was reminiscent of the situation in HD patient’s brains. These phenomena were confirmed in the zQ175 strain, and were accompanied by a differential impairment of the autophagy system between both tissues. Overall, these results demonstrated the suitability of the mouse retina as a research model for HD.