👤 Rhowena Jane Barbosa de Matos

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder thought to result from complex interactions between genetic and environmental risk factors. The APOE-ε4 allele is the strongest genetic contributor to late-onset AD, while a Western diet - high in saturated fats and refined sugars - is a major lifestyle-related risk factor associated with AD progression. However, how these two factors interact at an early stage of the disease remains unclear. In this study, we examined their combined impact on hippocampal synaptic transmission and plasticity in an AD mouse model and evaluated whether supplementation with d-serine, the key NMDAR co-agonist, could reverse the resulting deficits. To assess the combined effects of genetic and dietary risk factors on synaptic function, we crossed APP/PS1 mice with APOE-ε4 KI mice and generated four mouse lines: wild-type, APP/PS1, APOE-ε4, and APP/PS1/APOE-ε4. Hippocampal synaptic transmission and plasticity, NMDAR function and d- and l-serine levels were evaluated using a combination of electrophysiological recordings, pharmacological interventions and capillary electrophoresis in brain slices, under either control or Western diet conditions. A significant impairment of both basal excitatory synaptic transmission and long-term potentiation (LTP) was detected in APP/PS1 mice by 9 months of age. These deficits were significantly more pronounced in APP/PS1/APOE-ε4 mice. Notably, Western diet accelerated these impairments, with significant deficits already present at 7 months in both APOE-ε4 and APP/PS1/APOE-ε4 mice. Mechanistically, these impairments were associated with reduced d-serine availability and NMDAR hypofunction at CA3-CA1 synapses. This study provides direct evidence of a specific and synergistic interaction between the APOE-ε4 genotype and Western diet in advancing and exacerbating hippocampal synaptic dysfunction in an AD mouse model. These findings highlight d-serine/NMDAR signaling as a key mechanistic pathway through which genetic and environmental risk factors converge in early AD, and underscore the potential of targeting astrocytic d-serine biosynthetic pathways as a promising therapeutic strategy for APOE-ε4 carriers at risk for late-onset AD. Not applicable. The online version contains supplementary material available at 10.1186/s13195-026-01992-y. Show less

The present study investigated the effect of perinatal programming combined with exposure to a western diet on gene expression related to inflammation, neurodegeneration, and synaptic plasticity in the hippocampus of adult rats. Male rats from mothers fed either a standard diet or a western diet during gestation and lactation were used. All pups received only the standard chow diet from the 25th postnatal day (PND), and their body weight was analysed. Rats from the two groups fed the maternal diet were then divided on the 195 Adult rats submitted to a western diet during pregnancy and lactation showed signs of metabolic programming. In addition, glucose and total protein were found to have increased in the serum. The effect of acute exposure to a western diet is increased cholesterol. The western diet decreased gene expression of inflammatory factors ( Acute exposure to a western diet in adulthood alters pre-translational pathways ( Show less

Polycystic ovary syndrome (PCOS) is a complex, multi-system, heritable endocrinopathy that is a common cause of anovulatory infertility in reproductive-aged women. While insulin resistance (IR) is not a diagnostic feature, it is widespread in women with PCOS, and often more severe than in women of similar age and BMI. Conversely, women with rare Mendelian disorders of IR also present with features of PCOS. We hypothesize that PCOS is driven by underlying IR, which can be evaluated through a genetic approach. We curated and stratified 310 genes related to three mechanisms of IR using molecular and clinical criteria. We evaluated protein-altering genetic variation in 102 insulin signaling genes, 29 obesity genes, and 22 dyslipidemia genes from whole-exome sequencing data from 675 PCOS patients. 40 insulin signaling genes, 12 obesity genes, and 10 dyslipidemia genes were significantly enriched for protein-altering variation in PCOS cases compared to healthy population controls. Variants in these 62 significantly enriched genes affected 51% of PCOS cases in our study cohort. The 15 highest ranked genes were selected for follow-up: Show less

Type 2 diabetes (T2D) is associated with cognitive decline, but the role of We analyzed 883 Brazilian adults with T2D (median age 68 years) from primary care, excluding those with dementia. Cognitive function was assessed using Mini-Mental State Examination (MMSE), and Show less

Periprostatic adipose tissue (PPAT) has been recognized to associate with prostate cancer (PCa) aggressiveness and progression. Here, we sought to investigate whether excess adiposity modulates the methylome of PPAT in PCa patients. DNA methylation profiling was performed in PPAT from obese/overweight (OB/OW, BMI > 25 kg m Five thousand five hundred twenty-six differentially methylated CpGs were identified between OB/OW and NW PCa patients with 90.2% hypermethylated. Four hundred eighty-three of these CpGs were found to be located at both promoters and CpG islands, whereas the representing 412 genes were found to be involved in pluripotency of stem cells, fatty acid metabolism, and many other biological processes; 14 of these genes, particularly Results showed that the whole epigenome methylation profiles of PPAT were significantly different in OB/OW compared to normal weight PCa patients. The epigenetic variation associated with excess adiposity likely resulted in altered lipid metabolism and immune dysregulation, contributing towards unfavorable PCa microenvironment, thus warranting further validation studies in larger samples. Show less

In pediatric acute leukemias, reciprocal chromosomal translocations frequently cause gene fusions involving the lysine (K)-specific methyltransferase 2A gene (KMT2A, also known as MLL). Specific KMT2A fusion partners are associated with the disease phenotype (lymphoblastic vs. myeloid), and the type of KMT2A rearrangement also has prognostic implications. However, the KMT2A partner gene cannot always be identified by banding karyotyping. We sought to identify such partner genes in 13 cases of childhood leukemia with uninformative karyotypes by combining molecular techniques, including multicolor banding FISH, reverse-transcriptase PCR, and long-distance inverse PCR. Of the KMT2A fusion partner genes, MLLT3 was present in five patients, all with acute lymphoblastic leukemia, MLLT1 in two patients, and MLLT10, MLLT4, MLLT11, and AFF1 in one patient each. Reciprocal reading by long-distance inverse PCR also disclosed KMT2A fusions with PITPNA in one patient, with LOC100132273 in another patient, and with DNA sequences not compatible with any gene in three patients. The most common KMT2A breakpoint region was intron/exon 9 (3/8 patients), followed by intron/exon 11 and 10. Finally, multicolor banding revealed breakpoints in other chromosomes whose biological and prognostic implications remain to be determined. We conclude that the combination of molecular techniques used in this study can efficiently identify KMT2A fusion partners in complex pediatric acute leukemia karyotypes. Copyright © 2016 John Wiley & Sons, Ltd. Show less