Reducing HDAC6 ameliorates cognitive deficits in a mouse model for Alzheimer's disease.
Bottom Line: However, the role of specific HDACs in cognition and neurodegeneration remains poorly understood.Our data suggest that this therapeutic effect is, at least in part, linked to the observation that loss of HDAC6 renders neurons resistant to amyloid-β-mediated impairment of mitochondrial trafficking.Thus, our study suggests that targeting HDAC6 could be a suitable strategy to ameliorate cognitive decline observed in AD.
Affiliation: Department of Psychiatry and Psychotherapy, University Medical Center, Georg-August-University Goettingen, Goettingen, Germany.Show MeSH
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Mentions: We started our analysis by measuring HDAC6 levels in different regions of the adult mouse brain. Comparable levels of Hdac6 mRNA were detected in the hippocampus and cortical regions, while a significantly lower expression of Hdac6 was observed in the cerebellum (Fig 1A). This mRNA expression profile correlated with HDAC6 protein levels that were analysed via quantitative immunoblotting. HDAC6 protein levels were similar in the hippocampus and cortical regions but significantly lower in the cerebellum (Fig 1B, upper panel). Next, we analysed the subcellular localization of HDAC6 in the mouse hippocampus, a brain region important for the consolidation of memories and one of the first regions to be affected in AD patients (Mesulam, 1999). HDAC6 protein levels were mainly restricted to the cytoplasm and below detection level in the nucleus (Fig 1B, lower panel). This subcellular distribution of HDAC6 was confirmed in hippocampal neurons in vitro. Since we were unable to obtain an anti-HDAC6 antibody suitable for immunocytochemistry, we generated a lentivirus to express Hdac6-eGFP in primary hippocampal neurons. The Hdac6-eGFP signal was restricted to the cytoplasm (Fig 1C). To further analyse the role of HDAC6, we generated Hdac6 knockout mice by replacing exons 10–13 of the mouse Hdac6 gene with a neomycin cassette (Hdac6−/− mice). This led to the complete loss of Hdac6 mRNA and protein levels when measured in the hippocampus and cortex as shown by semi-quantitative PCR (Fig 1D, upper panel) and immunoblot, respectively (Fig 1D, lower panel). Notably, gross brain morphology and brain mass (Fig 1E) and body mass (Supporting Information Fig S1) were normal in Hdac6−/− mice.
Affiliation: Department of Psychiatry and Psychotherapy, University Medical Center, Georg-August-University Goettingen, Goettingen, Germany.