One of the most well-known genetic factors remains the APOE gene. Its APOE4 variant significantly increases the risk of late-onset Alzheimer’s disease, whereas the APOE2 variant, on the contrary, is associated with lower risk and greater longevity. The reasons for this have long remained unclear.
Researchers at the Buck Institute compared neurons derived from stem cells that differed only in their APOE variant. They found that neurons with APOE2 accumulated less DNA damage and more actively engaged DNA repair systems. Under stress (radiation or a chemotherapeutic agent), they were less likely to enter senescence—a damaged, “frozen” cellular state that becomes increasingly common with age.
A similar pattern was observed in the hippocampus of aged mice carrying human APOE variants. In APOE2 carriers, the structure of the nucleus and nuclear envelope was better preserved.
Interestingly, adding the APOE2 protein to neurons with the “risk” APOE4 variant partially reduced DNA damage signals. This suggests that the protective effect may be at least partially transferable.
While the mechanism is not yet fully understood, it is already clear that APOE influences not only cholesterol metabolism and amyloid pathways but also how effectively neurons protect their genome. This opens the way to searching for compounds that could mimic the protective properties of APOE2 in people with high genetic risk.