Researchers at the Gladstone Institutes have unveiled significant insights into the hyperexcitability of hippocampal neurons associated with the APOE4 allele, a major genetic risk factor for Alzheimer’s disease. Their study, published in Nature Aging, demonstrates that young mice carrying the human APOE4 variant exhibit increased neuronal excitability before any cognitive decline is observed. Specifically, these E4-KI mice showed heightened rates of interictal spikes (IIS) in hippocampal regions, correlating with later cognitive impairments as measured by the Morris water maze test.

The findings highlight the early neuronal changes linked to APOE4 that precede clinical symptoms, offering a potential window for therapeutic intervention. The study reveals that the hyperexcitability observed in young E4-KI mice is characterized by smaller CA3 pyramidal neurons, which may contribute to their increased excitability. Notably, the research also identifies Nell2 as a critical protein involved in this process; knocking down Nell2 mitigated the hyperexcitability, suggesting a pathway for therapeutic targeting.

This study shifts the research paradigm by emphasizing the importance of early intervention in Alzheimer’s disease. The ability to reverse neuronal changes through manipulation of Nell2 indicates that the pathological processes may not be irreversible, opening avenues for developing treatments that could prevent or delay the onset of cognitive decline in at-risk populations. Future studies will be essential to explore the mechanisms by which Nell2 operates and to assess the feasibility of translating these findings into clinical applications.

Source: lifespan.io