👤 Mona Mashayekhi

Alzheimer's disease (AD) is a complex neurodegenerative disorder characterized by progressive memory impairment and cognitive decline, significantly impacting the quality of life for millions worldwide. Understanding the intricate molecular pathways linking AD pathology to memory dysfunction is crucial for developing effective therapies. This narrative review aims to elucidate the key molecular mechanisms underlying memory impairment in AD. We conducted a comprehensive literature search across major scientific databases (e.g., PubMed, Scopus, Web of Science) focusing on peer-reviewed studies (original research, reviews) exploring the molecular links between AD pathology and memory deficits. The review identifies and details several interconnected molecular pathways driving memory impairment in AD: (1) Synaptic dysfunction and neuronal loss triggered by amyloid-β (Aβ) peptide accumulation and aggregation; (2) Intracellular transport disruption and neurodegeneration caused by tau protein hyperphosphorylation and aggregation; (3) Exacerbation of cognitive deficits by neuroinflammation, mediated through activated microglia and pro-inflammatory cytokines (e.g., IL-1β, TNF-α, IL-6); (4) Impairment of synaptic plasticity and cognitive function due to dysregulation of neurotrophic factors, particularly brain-derived neurotrophic factor; (5) Contributory roles of oxidative stress, mitochondrial dysfunction, disrupted neurotransmission (e.g., acetylcholine, GABA), and apoptotic pathways. This review comprehensively unravels the critical molecular links between AD pathology and memory impairment, emphasizing the interplay of Aβ, tau, neuroinflammation, neurotrophic factor dysregulation, and other mechanisms. Targeting these interconnected pathways represents a promising strategic approach for developing therapies to mitigate cognitive decline and improve outcomes in AD patients. Show less

Dyslipidemia is common in people with HIV (PWH) and linked to cardiometabolic disease risk. Subcutaneous adipose tissue (SAT) regulates lipid storage and release, but how SAT cellular composition might influence circulating lipids in PWH on contemporary antiretroviral therapy (ART) is not well defined. Cross-sectional, observational cohort of PWH on long-term contemporary ART with virologic suppression. We performed untargeted fasting plasma lipidomic profiling on 127 individuals with a range of metabolic fitness (non-diabetes, prediabetes, diabetes). Adjusted logistic and linear regression models identified lipid species associated with diabetes status and HOMA2-IR, respectively. Linear regression assessed the relationship between abdominal SAT cell composition from single-cell RNA sequencing with circulating lipid classes (n = 59). The median age was 48 years, body mass index 31.5 kg/m 2 , and 48% self-identified as non-White, with 23% women. Diabetes as a dichotomous outcome had few differences in lipid species. In contrast, HOMA2-IR was associated with higher levels of several species of tri- and diacylglycerols and inversely associated with phosphatidylcholine, phosphatidylethanolamine species, and many of their derivatives among those without diabetes. Adipose tissue microvasculature remodeling, characterized by a reduction in capillary endothelium and decreased expression of key lipid trafficking receptors ( LPL, GPIHBP1 ), was associated with the insulin-resistant lipidomic signature. Adipose tissue microvasculature remodeling in PWH on contemporary ART was associated with changes in several plasma lipid species, which are also linked to insulin resistance. Interventions targeting adipose tissue endothelial dysfunction may improve metabolic health in PWH on long-term ART. Show less

Tumor cells release extracellular vesicles (EVs) that contribute to the polarization of macrophages towards tumor-associated macrophages (TAMs). High expression levels of the RNA binding protein IGF2BP2/IMP2 are correlated with increased tumor cell proliferation, invasion, and poor prognosis in the clinic. However, there is a lack of understanding of whether IMP2 affects the cargo of cancer cell-derived EVs, thereby modulating macrophage polarization. EVs were isolated from IMP2-expressing HCT116 parental cells (WT) and CRISPR/Cas9 IMP2 knockout (KO) cells. EVs were characterized according to MISEV guidelines, microRNA cargo was assessed by microRNA-Seq, and the protein cargo was analyzed by proteomics. Primary human monocyte-derived macrophages (HMDMs) were polarized by EVs, and the expression of genes and surface markers was assessed using qPCR and flow cytometry, respectively. Morphological changes of macrophages, as well as the migratory potential of cancer cells, were assessed by the Incucyte EVs from WT and KO cells had a similar size and concentration and were positive for 25 vesicle markers. The expression of tumor-promoting genes was higher in macrophages polarized with WT EVs than KO EVs, while the expression of TNF and IL6 was reduced. A similar pattern was observed in macrophages from zebrafish larvae treated in vivo. WT EV-polarized macrophages showed a higher abundance of TAM-like surface markers, higher matrix degrading activity, as well as a higher promotion of cancer cell migration. MicroRNA-Seq revealed a significant difference in the microRNA composition of WT and KO EVs, particularly a high abundance of miR-181a-5p in WT EVs, which was absent in KO EVs. Inhibitors of macropinocytosis and phagocytosis antagonized the delivery of miR-181a-5p into macrophages and the downregulation of the miR-181a-5p target DUSP6. Proteomics data showed differences in protein cargo in KO vs. WT EVs, with the differentially abundant proteins mainly involved in metabolic pathways. WT EV-treated macrophages exhibited a higher basal oxygen consumption rate and a lower extracellular acidification rate than KO EV-treated cells. Our results show that IMP2 determines the cargo of EVs released by cancer cells, thereby modulating the EVs' actions on macrophages. Expression of IMP2 is linked to the secretion of EVs that polarize macrophages towards a tumor-promoting phenotype. Show less

During early mammalian development, transient pools of pluripotent cells emerge that can be immortalised upon stem cell derivation. The pluripotent state, 'naïve' or 'primed', depends on the embryonic stage and derivation conditions used. Here we analyse the temporal gene expression patterns of mouse, cattle and porcine embryos at stages that harbour different types of pluripotent cells. We document conserved and divergent traits in gene expression, and identify predictor genes shared across the species that are associated with pluripotent states Show less