Репозиторий Университета

© 2021 Elsevier Inc. Methylmercury (MeHg) is a persistent environmental neurotoxicant that may cause adverse neurodevelopmental effects. Previous studies showed that developmental MeHg exposure caused damage to brain functions that were unmasked after a silent period of years or decades. However, the underlying mechanisms of the latent neurotoxicity associated with MeHg exposure from earlier developmental stages have yet to be fully understood. Herein, we established a Caenorhabditis elegans (C. elegans) model of developmental MeHg latent toxicity. Synchronized L1 stage worms were exposed to MeHg (0, 0.05, 0.5 and 5 μM) for 48 h. Swimming moving speeds at adulthood were analyzed in worms exposed to MeHg exposure at early larvae stages. Worms developmentally exposed to MeHg had a significant decline in swimming moving speed on day 10 adult stage, but not on day 1 or 5 adult stage, even though the mercury level in the worms exposed to 0.05 or 0.5 μM MeHg were below the quantification limit on day 10 adult. Day 10 adult worms treated with MeHg showed a significant decrease in bending angle and bending frequency during swimming. Furthermore, their reduced moving speeds tended to increase during the 300-s swimming experiment. Dopamine signaling is known to be involved in the regulation of worms' moving speed. Accordingly, the moving speed of worms with cat-2 (mammalian tyrosine hydroxylase homolog) mutation or dat-1 deletion were assayed on day 10 adult. The cat-2 mutant worms did not show a decline in moving speeds, body bends or bending angles during swimming on day 10 adult stage. Analyses of moving speeds of worms with dat-1 deletion showed that the moving speeds were further reduced after MeHg exposure. However, the effects of MeHg and dat-1 deletion were not synergistic, as the interaction between these parameters did not attain statistical significance. Altogether, our results suggest that developmental MeHg exposure reduced moving speed, and this latent toxicity was less pronounced in the context of deficient production of dopamine synthesis. Tyrosine hydroxylase plays an important role in regulating dopamine-mediated modulation of neurobehavioral functions. These findings uncovered a pivotal role of dopamine and its metabolism in the latent neurotoxic effects of MeHg.

© The Author 2018. An in silico approach was adopted to identify potential cyclooxygenase inhibitors through molecular docking studies. Four potentially active molecules were generated by fusion of dopamine with ibuprofen or ketorolac derivatives. The binding mode of the considered ligands to cyclooxygenase-1 and cyclooxygenase-2 isoforms was described using Autodock Vina. Preliminary docking to full cyclooxygenase isoforms structures was used to determine possible binding sites for the described dopamine-derived ligands. The following more accurate docking iteration to the described binding sites was used to achieve better conformational sampling. Among the studied molecules, IBU-GABA-DA showed preferable binding to cyclooxygenase active site of cyclooxygenase-1, while IBU-DA bound to peroxidase site of cyclooxygenase-1, making these ibuprofen-comprising ligands a base for further research and design of selective cyclooxygenase- 1 inhibitors. Keterolac-derived ligands KET-DA and KET-GABA-DA demonstrated binding to both cyclooxygenase isoforms at a side pocket, which does not relate to any known functional site of cyclooxygenases and needs to be further investigated.

© 2018 Bentham Science Publishers. Patients with Parkinson’s disease (PD) are looking forward to new therapeutic strategies that may gradually decelerate the rate of neurodegenerative decline, associated with mobility restrictions and related morbidity. Its continuous neurodegenerative process, exacerbated by genetic mutations or environmental toxins, involves a progressive reduction in the dopamine neurotransmission levels, synaptic uptake density, oxidative glucose intake, deficient striatal lactate accumulation and chronic inflammation. Over the last decade, novel bioproducts have received considerable interest due to their unique potential of unifying nutritional, safety and therapeutic natural effects. Some nutraceuticals play a crucial role in the control of the signaling transduction pathways in neurotransmission and inflammation affected in PD, and some natural compounds can beneficially interact with each one of these biological mechanisms to slow down disease progression. Atremorine, a novel plant-derived nutraceutical, probably with a neuroprotective effect in the dopaminergic neurons of the substantia nigra (pars compacta), is a prototype of this new category of bioproducts with potential effects in PD. The major focus of this review will be on the current knowledge and biomedical investigation strategies through a plant-derived neuroprotective approach to improve life quality in PD patients, being of paramount importance for health providers, caregivers and the patients themselves.