Kamila Souto Leichtweis

Background: The Wnt/β-catenin signaling pathway plays a pivotal role in embryonic development, maintenance of the central nervous system, and the formation of neuronal circuits. Disruption of this pathway is closely associated with oncogenesis and neurodegenerative diseases, notably Alzheimer’s disease. Flavonoids such as quercetin derivatives have emerged as promising neuroprotective agents. This study investigates the impact of 3-O-methylquercetin (3OMQ), a methylated quercetin metabolite, on Wnt/β-catenin signaling and its potential relevance in neurodegenerative disease models. Methods: The ability of 3OMQ to modulate Wnt/β-catenin activity was analyzed using a luciferase-based reporter assay in both neural and non-neural cell lines. Cell viability assays evaluated cytotoxicity at various concentrations. We mapped 3OMQ activity within the pathway using targeted cell signaling experiments. Docking and molecular dynamics simulations suggested glycogen synthase kinase 3β (GSK3β) as a putative target of 3OMQ. Finally, we employed a mouse model of acute amyloid-β oligomer (AβO) toxicity to assess the in vivo effects of 3OMQ on spatial memory and Wnt-related gene expression. Results: We compared the flavonoids quercitrin, quercetin, and 3-O-methylquercitrin (3OMQ) with pharmacologically active compounds in a gene reporter assay (TOPFLASH) using Wnt-sensitive RKO cells treated with Wnt3a-conditioned medium. XAV-939 and PNU-74654 showed inhibitory activity, while BIO, CHIR99021, quercitrin, and 3OMQ enhanced the Wnt/β-catenin pathway. Notably, 3OMQ potentiated this pathway at concentrations 5–10 times lower than quercitrin and outperformed 1 μM BIO at 10 μM without cytotoxicity, highlighting its remarkable potency. Mechanistically, 3OMQ acts downstream of initial membrane activation and upstream of the β-catenin destruction complex. Consistently, molecular docking indicates a strong interaction with GSK3, a central regulator of the pathway. In adult mice, 3OMQ administration prevented AβO-induced recognition memory deficits and favored normalization of Wnt-related gene expression. Conclusions: These findings identify 3OMQ as a potent positive modulator of the Wnt/β-catenin pathway, with both in vitro and in vivo neuroprotective effects. Targeting Wnt signaling with compounds such as 3OMQ holds promise for maintaining neuronal health and developing therapeutic strategies for neurodegenerative conditions.

Caramujos do gênero Biomphalaria são hospedeiros do parasito Schsitosoma mansoni, bem como, bioindicadores de qualidade ambiental. Esses caramujos usam carboidratos como fonte primária de energia e aminoácidos na síntese de “novo” de glicose, pela gliconeogênese. A concentração do Ca2+ exógeno afeta o metabolismo energético dos caramujos. Este estudo avaliou o uso de uma via metabólica alternativa por Biomphalaria tenagophila e B. glabrata expostas a 20, 40, 60, 80 e 100 mg/L de CaCO3, por 30 dias, a partir das concentrações de proteína totais, ureia, ácido úrico e creatinina, obtidas utilizando espectrofotômetro. Para cada grupo, foram utilizados quinze caramujos, dos quais foram obtidos amostras compostas de hemolinfa. De maneira geral, houve aumento de proteínas totais e redução de ureia, em ambas as espécies, expostas às maiores concentrações de CaCO3, comparado ao controle. O ácido úrico também aumentou para as duas espécies nas maiores concentrações de CaCO3. Maiores valores de creatinina foram observados em B. tenagophila e B. glabrata expostas, respectivamente, a 20 e 40 mg CaCO3. O uso de proteínas como substrato energético foi observado principalmente na exposição a 20 mg de CaCO3, além de particularidades na regulação de mecanismos fisiológicos pelas espécies como hospedeiras de S. mansoni.

Maternal separation (MS) is an animal model widely used to evaluate the influence of early-life stress exposure on ethanol consumption and dependence. The goal of this study was to evaluate the effects of brief and prolonged MS on the pattern of consumption and ethanol conditioned place preference (CPP) in male and female rats during adolescence and adulthood. Wistar rat pups were separated daily from their dams for 15 or 180 minutes during the 2 to 10 postnatal days (PND). In adolescence, half of the litter from each group was evaluated in the ethanol consumption test using the three-bottle test choice paradigm. In addition, using biased procedure, ethanol-conditioned place preference was also evaluated. In adulthood, the other half of the litter was evaluated on the same tests. Our results showed that there are differences in consumption pattern and in alcohol reinforcement between males and females, adolescents and adults. While prolonged MS had no effect on total ethanol consumption in adolescents of both sexes, it induced CPP in these animals. In turn, in adults, previous exposure to prolonged MS increased ethanol consumption without altering ethanol-CPP.