Determinação da segurança e potencial eficácia de selenoésteres em um modelo de doença de Alzheimer em Caenorhabditis elegans

Abstract

Alzheimer ́s disease (AD) is characterized as the main cause of dementia among elderly. This disease has no cure, once the drugs available to the treatment, have a limited therapeutic range. It was already to demonstrated in experimental models, the role of selenium organic compounds, to stops the effects caused by AD manifestation. In previous in vitro studies, diihydropyrimidinones compounds, known as selenoesters, demonstrated antioxidant and metals chelator properties, and inhibitory effect in the activity of acetylcholinesterase enzyme (AChE), which makes them potential candidates for multi-target treatment for the disease. However, the effects of these compounds, haven ́t been demonstrated in vivo models for the AD. Aiming to evaluate these, the Caenorhabditis elegans (C.elegans) is a promisor model, since there are transgenic strains (example GMC101) that express and aggregate the beta-amyloid peptide (Aβ), in the same condition of the aggregates found in the brain of individuals that develop the disease. The objective of this study was evaluate the multi-target effects of selenoester compounds in the strain GMC101, and verify the main molecular mechanisms of action. For this, initially we submitted the worms in an acute exposition with the compounds FA83, FA84, FA85, FA86, FA87, FA88, FA90 e FA130 and 48 hours after we verify the rate of live worms. After 48 hours of treatment the worms were maintaining at a temperature higher than usual (25°C) for that there was the expression and aggregation of Aβ. From that assessed the egg-laying (24 hours after at 25°C), swimming and paralysis (72 hours after). To verify the protector effect of compounds during the lifespan, we performed the longevity assay. It was verified the effects of compounds that obtained better effects in vitro and in vivo studies (FA86, FA90 e FA130), under aspects related to neurotransmission in the worm, through measurement of AChE activity. From the results obtained, investigated the molecular mechanism of action of selenoesters via chaperones and autophagy. Besides that, performed the target of aggregates with dye X-34. The data were analyzed through the GraphPad Prism 7.0 software. In the concentrations tested (5, 10, 100 e 200μM) found only a significant mortality in the compounds FA86 and FA90 at 200 μM. Being that one compounds that reduced significantly the rate of paralyzed worms, after the aggregation induction of Aβ, was the FA90 (200μM). However, this effect was not able to extend the lifespan of treated worms, where only the compound FA130, demonstrated protector effect in the longevity of worms. When we tested the three compounds (FA86, FA90 and FA130) that demonstrate the better results in vitro and previous studies in vivo, all these had effect in the cholinergic signaling, improving the egg-laying of worms submitted to exposition with agonist cholinergic levamisole. However, only the compound FA90 reduced the AChE activity. Beside that the same improve the movements rate in the swimming assay of worms. Acting through chaperones by inducing the increase of genes expression hsp-6 and hsp-4 in C.elegans. The compound demonstrated the better effect in the contain the pathologic manifestations that mimic the AD in C.elegans.