APOE2 gene protects brain from Alzheimer's by reducing DNA damage
A study from the Buck Institute reveals how the APOE2 gene protects against Alzheimer's disease. Researchers found that neurons with APOE2 are better at repairing DNA damage and resisting cellular senescence, an age-related decline. This contrasts with the high-risk APOE4 variant. The findings, validated in mice, suggest APOE2's protective protein effects may be transferable, opening new therapeutic avenues for Alzheimer's.
APOE gene variants
▪People who carry the APOE2 gene variant tend to live longer and have a lower risk of Alzheimer's disease.
▪The apolipoprotein E (APOE) gene exists in three common forms: APOE2, APOE3, and APOE4, which differ by only two amino acids.
▪APOE4 is the strongest known genetic risk factor for late-onset Alzheimer's disease, which typically develops after age 65.
DNA damage protection
▪A study from the Buck Institute for Research on Aging suggests the APOE2 gene helps neurons protect their DNA.
▪RNA sequencing showed that APOE2 GABAergic neurons strongly activated pathways involved in DNA repair and damage response.
▪Researchers found that neurons with the APOE2 variant accumulated less DNA damage and had significantly fewer DNA strand breaks than other variants.
Cellular senescence resistance
▪The Buck Institute study suggests APOE2 helps neurons avoid senescence, a damaged and poorly functioning cellular state common with age.
▪When exposed to DNA-damaging stress, APOE2 neurons showed lower levels of senescence markers, including p16 and CRYAB, than other variants.
Transferable protein effects
▪This finding suggests APOE2's protective effect may be transferable and not limited to individuals born with the gene variant.
▪Adding recombinant APOE2 protein to APOE4 neurons reduced their DNA damage signaling after radiation exposure.
Mouse model validation
▪Compared to mice with APOE3 or APOE4, APOE2 mice had healthier brain cell characteristics, including smaller nucleoli and better-preserved heterochromatin.
▪Experiments on older mice engineered with human APOE genes showed similar protective effects for the APOE2 variant in the hippocampus.
Therapeutic implications
▪The study's findings point toward new therapeutic strategies for Alzheimer's disease.
▪Future treatments could improve DNA repair or remove senescent cells to mimic APOE2's benefits for people with the high-risk APOE4 variant.
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