APOE genotype-specific methylation patterns are linked to Alzheimer disease pathology and estrogen response.

The joint effects of APOE genotype and DNA methylation on Alzheimer disease (AD) risk is relatively unknown. We conducted genome-wide methylation analyses using 2,021 samples in blood (91 AD cases, 329 mild cognitive impairment, 1,391 controls) and 697 samples in brain (417 AD cases, 280 controls). We identified differentially methylated levels in AD compared to controls in an APOE genotype-specific manner at 25 cytosine-phosphate-guanine (CpG) sites in brain and 36 CpG sites in blood. Additionally, we identified seven CpG sites in the APOE region containing TOMM40, APOE, and APOC1 genes with P < 5 × 10-8 between APOE ε4 carriers and non-carriers in brain or blood. In brain, the most significant CpG site hypomethylated in ε4 carriers compared to non-carriers was from the TOMM40 in the total sample, while most of the evidence was derived from AD cases. However, the CpG site was not significantly modulating expression of these three genes in brain. Three CpG sites from the APOE were hypermethylated in APOE ε4 carriers in brain or blood compared in ε4 non-carriers and nominally significant with APOE expression in brain. Three CpG sites from the APOC1 were hypermethylated in blood, which one of the 3 CpG sites significantly lowered APOC1 expression in blood using all subjects or ε4 non-carriers. Co-methylation network analysis in blood and brain detected eight methylation networks associated with AD and APOE ε4 status. Five of the eight networks included genes containing network CpGs that were significantly enriched for estradiol perturbation, where four of the five networks were enriched for the estrogen response pathway. Our findings provide further evidence of the role of APOE genotype on methylation levels associated with AD, especially linked to estrogen response pathway.

Female-specific association between the APOE E4 allele and age at diagnosis of glaucoma in UK Biobank.

OBJECTIVE: To explore the impact of the apolipoprotein E (APOE) E4 allele in the gender-specific aging process in glaucoma by illustrating the interaction between risk factors, including the APOE E4 allele, gender and intraocular pressure (IOP), for age at diagnosis (AAD) of glaucoma. DESIGN: A cross-sectional study included UK Biobank participants with complete data (2006-2010) for analysis. Data were analyzed in December 2023. PARTICIPANTS: 2,236 glaucoma patients and 103,232 controls. METHODS: We evaluated multivariable-adjusted associations of AAD of glaucoma, APOE E4 allele (0: absence; 1: presence), and IOP using linear mixed model (LMM) analyses across groups stratified by AAD of mean age of menopause (50 years) and gender. MAIN OUTCOMES MEASURES: AAD of glaucoma, APOE E4 allele and IOP. RESULTS: Glaucoma patients were older and had a higher percentage of males and a higher mean IOP compared to controls (all P < 0.001). Further stratifying the glaucoma patients by AAD of 50 and gender, lower IOP (Model 1 adjusted by age, ßIOP=-0.096±0.041, P=0.019) and positive APOE E4 allele (Model 2 adjusted by age and IOP, ße4=1.093±0.488, P=0.026) were associated with an older AAD in females with an AAD < 50 years under univariate LMM. In multivariate LMM adjusted by age (Model 3), the effect size of both factors increased in the multivariate model as the beta-value increased. (ßIOP=-0.111±0.040, P=0.007; ße4=1.235±0.485, P=0.012) (Model 1 vs Model 3: P=0.011). In females with an AAD ≥50 years, only positive APOE E4 allele (adjusted by age and IOP, ße4=-1.121±0.412, P=0.007) was associated with a younger AAD. In males, only higher IOP was associated with an older AAD in those with an AAD ≥50 years (ßIOP=0.088±0.032, P=0.006). CONCLUSIONS: APOE E4 allele may initially delay and later accelerate the development of glaucoma in females around the transition period of 50 years, which is the mean age of menopause, and importantly, this is independent of IOP. Understanding the specific transition states and modifiable factors within each age phase is crucial for developing interventions or strategies that promote healthy aging.