👤 Giuseppe Aceto

The apolipoprotein E (APOE) gene represents the strongest genetic determinant of sporadic Alzheimer's disease (AD), yet its interaction with sex-specific endocrine factors remains poorly understood. Lifetime estrogen exposure, estimated through reproductive lifespan, may modulate neurodegenerative risk, but findings are inconsistent. Previous studies have examined reproductive factors and APOE interactions in relation to cognitive outcomes, but dose-dependent effects across all APOE alleles (ε2, ε3, ε4) in clinically diagnosed AD patients remain underexplored. This study investigates the joint effects of reproductive lifespan, age at natural menopause (ANM), and APOE genotype on AD risk in females. A total of 396 female participants (103 with AD, 293 cognitively healthy controls) were retrospectively analyzed. Demographic, clinical, and reproductive data were extracted from medical records. APOE genotyping was performed by sequencing rs429358 and rs7412 polymorphisms. Logistic regression models tested associations between ANM, reproductive lifespan, and AD diagnosis, adjusting for education, body mass index (BMI), smoking, diabetes, hypertension, and number of children. Moderation analyses assessed the interaction between reproductive variables and APOE ε2, ε3, and ε4 alleles, and were followed by simple slope analyses to clarify the direction of significant effects. AD females exhibited later ANM (50.3 ± 4.4 vs. 48.3 ± 6.2 years; This work provides novel evidence that extended ovarian function is associated with increased AD vulnerability in females, particularly among APOE ε4 carriers. These findings highlight a dose-dependent, genotype-specific interaction between reproductive aging and neurodegeneration, suggesting APOE as a molecular bridge linking estrogenic exposure and AD risk. Show less

Protein post-translational modifications (PTM) play a crucial role in the modulation of synaptic function and their alterations are involved in the onset and progression of neurodegenerative disorders. S-palmitoylation is a PTM catalyzed by zinc finger DHHC domain containing (zDHHC) S-acyltransferases that affects both localization and activity of proteins regulating synaptic plasticity and amyloid-β (Aβ) metabolism. Here, we found significant increases of both zDHHC7 expression and protein S-palmitoylation in hippocampi of both 3×Tg-AD mice and post-mortem Alzheimer's disease (AD) patients. Chronic intranasal administration of the S-palmitoylation inhibitor 2-bromopalmitate counteracted synaptic plasticity and cognitive deficits, reduced the Aβ deposition in the hippocampus and extended the lifespan of both male and female 3×Tg-AD mice. Moreover, hippocampal silencing of zDHHC7 prevented the onset of cognitive deficits in the same experimental model. We also identified a FoxO1-mediated epigenetic mechanism inducing zDHHC7 expression, which was triggered by brain insulin resistance in 3×Tg-AD mice. Finally, in hippocampi of AD patients S-palmitoylation levels of Beta-Secretase 1 were associated with Aβ 1 to 42 load and they inversely correlated with Mini Mental State Examination scores. Our data reveal a key role of both zDHHC7 overexpression and protein hyperpalmitoylation in the onset and progression of AD-related alterations of synaptic plasticity and memory. Show less

Down syndrome (DS) is the most frequent genetic cause of intellectual disability and is strongly associated with Alzheimer's disease (AD). Brain insulin resistance greatly contributes to AD development in the general population and previous studies from our group showed an early accumulation of insulin resistance markers in DS brain, already in childhood, and even before AD onset. Here we tested the effects promoted in Ts2Cje mice by the intranasal administration of the KYCCSRK peptide known to foster insulin signaling activation by directly interacting and activating the insulin receptor (IR) and the AKT protein. Therefore, the KYCCSRK peptide might represent a promising molecule to overcome insulin resistance. Our results show that KYCCSRK rescued insulin signaling activation, increased mitochondrial complexes levels (OXPHOS) and reduced oxidative stress levels in the brain of Ts2Cje mice. Moreover, we uncovered novel characteristics of the KYCCSRK peptide, including its efficacy in reducing DYRK1A (triplicated in DS) and BACE1 protein levels, which resulted in reduced AD-like neuropathology in Ts2Cje mice. Finally, the peptide elicited neuroprotective effects by ameliorating synaptic plasticity mechanisms that are altered in DS due to the imbalance between inhibitory vs. excitatory currents. Overall, our results represent a step forward in searching for new molecules useful to reduce intellectual disability and counteract AD development in DS. Show less