Butirilcolinesterase humana e intoxicaçao por agrotóxicos

Orientadora: Eleidi A. Chautard Freire MaiaMonografia (Bacharelado) - Universidade Federal do Paraná. Setor de Ciencias Biológicas. Curso de Graduaçao em Ciencias BiológicasResumo : A hipótese proposta por esse estudo foi de que a variabilidade genética da butirilcolinesterase humana (BChE; 3 .l.1. 8) possa influenciar no risco de intoxicação clínica por pesticidas organofosforados e/ou carbamatos . Constituiu-se em uma pesquisa piloto a partir da qual se pudessem obter informações para a elaboração de um projeto de tese viável e ao mesmo tempo suficiente para testar a hipótese mencionada. Foi examinada a atividade e a variabilidade genética da BChE referente aos locos BCHE e CHE2, em 63 lavradores considerados intoxicados por agrotóxicos e 40 controles (97,5% agentes de saúde), cujas informações e amostras de soro foram obtidas no Laboratório Central do Estado do Paraná. As freqüências dos fenótipos do loco BCHE, determinadas com base em inibição enzimática, não se 'mostraram diferentes nessas amostras, tendo-se detectado apenas uma variante não usual entre os intoxicados (fenótipo BCHE DA; 1,59% ± 1,40% E.P.) e nenhuma variante não usual entre os controles. As freqüências dos fenótipos do loco CHE2 também não se mostraram diferentes entre essas duas amostras, sendo as freqüências do fenótipo CHE2 C5+, respectivamente, 11,11% ± 3,96% e 12,50% ± 5,23%, em intoxicados e controles. A atividade média da BChE se mostrou estatisticamente diferente entre essas duas amostras, tendo sido mais baixa nos intoxicados (6,52 UI. ± 1,73 D.P.) do que nos controles (7,96 UI. ± 1,49 D.P.). Talvez pela falta de informações clínicas, que permitissem melhor seleção do grupo intoxicado, os dados não foram suficientes para corroborar ou excluir a hipótese proposta. Vale salientar que a única variação não usual do loco BCHE foi encontrada em um dos 5 casos com sintomas de intoxicação descritos

Identifying pathways modulating sleep duration : from genomics to transcriptomics

Recognizing that insights into the modulation of sleep duration can emerge by exploring the functional relationships among genes, we used this strategy to explore the genome-wide association results for this trait. We detected two major signalling pathways (ion channels and the ERBB signalling family of tyrosine kinases) that could be replicated across independent GWA studies meta-analyses. To investigate the significance of these pathways for sleep modulation, we performed transcriptome analyses of short sleeping flies’ heads (knockdown for the ABCC9 gene homolog; dSur). We found significant alterations in gene-expression in the short sleeping knockdowns versus controls flies, which correspond to pathways associated with sleep duration in our human studies. Most notably, the expression of Rho and EGFR (members of the ERBB signalling pathway) genes was down- and upregulated, respectively, consistently with the established role of these genes for sleep consolidation in Drosophila. Using a disease multifactorial interaction network, we showed that many of the genes of the pathways indicated to be relevant for sleep duration had functional evidence of their involvement with sleep regulation, circadian rhythms, insulin secretion, gluconeogenesis and lipogenesis

On novel functions of cholinesterases

The non-specificity of cholinesterases to cholinergic innervated tissues, their early onset during embryogenesis of many organisms, and their non-cholinolytic aryl acylamidase activity, indicate that these enzymes are involved with physiological processes other than the termination of nervous impulse. In this study, cholinesterases expression and function were investigated during the development of two model organisms, chicken (Gallus gallus) and zebrafish (Danio rerio), with the focus on non-cholinolytic and non-catalytic events. In chicken, the pineal organ was investigated taking into consideration: a) its similarity to the eye, as earlier studies suggested a relevance of cholinesterases to retina embryogenesis, b) its relevance on controlling physiological functions following a circadian rhythm, and c) its disfunction in pathological states, which also present altered cholinesterases expression, like Alzheimer’s disease. Indeed, in this study, a remarkable developmentally regulated switch from butyrylcholinesterase (BChE) to acetylcholinesterase (AChE) expression during pineal embryogenesis was found, in association with cell proliferation and differentiation, respectively. Even more, AChE-positive cells were shown to guide the pineal epithelium remodeling (leading to follicles development), indicating it plays a pivotal role in pineal embryogenesis. Besides, the appearance of follicular supportive cells correlated with this remodeling onset, followed by photoreceptor cells differentiation, indicating that these events are interconnected. Furthermore, AChE was demonstrated to be active in cells undergoing apoptosis during pineal embryogenesis, corroborating earlier in vitro studies indicating its involvement with the apoptotic process. However, the mechanism of action of cholinesterases in most of these developmental events is not clear, in particular whether the function could be structural or non-cholinolytic. Using zebrafish as a second model organism, a non-cholinolytic activity of AChE was investigated, from the time its transcription begins until larval development of this organism. This study revealed a particular profile of the AChE-associated aryl acylamidase activity (AAA) during development of zebrafish. AAA was particularly more pronounced than the esterase activity during zebrafish embryogenesis, indicating a relevance of this activity during early development. This non-cholinolytic activity was further investigated in human recombinant BChE wild-type and mutant proteins to address its catalytic power in enzymes with low cholinergic functionality. Altogether, these three studies on novel functions of cholinesterases address aspects of these enzymes also in relation to serotonin, as follow: a) cholinesterases are implicated in the development of the pineal gland, an organ controlling serotonin metabolism; b) a temporal high sensitivity of zebrafish embryos towards serotonin administration correlated with AChE expression onset during their blastula period, and c) serotonin directly interacts with cholinesterases, demonstrated through a non-competitive inhibition of the AAA activity on purified recombinant human BChE. This PhD work, therefore, presents strong evidence of the AChE involvement with morphogenesis, with further implications of its expression for pineal cells differentiation and apoptosis. It also writes further history on the little investigated side activity of cholinesterases, the aryl acylamidase, and supports a link between cholinergic and serotonergic systems

A chronobiological policy to decrease the burden of hypertension and obesity in low- and middle-income population

The cardiovascular structure is temporally organized in both health and disease. The link between obesity and hypertension is elevated sympathetic nervous system activity and hormonal activity which present a clear rhythmicity, with the pineal, corticosteroid and leptin systems being those most implicated. Also, genetic mutations or deletions have implicated peripheral clock genes in the regulation of glucose homeostasis, lipid synthesis and adipogenesis, which are associated with obesity and type 2 diabetes mellitus. As hypertension and obesity are related, and the treatments of these disorders are well established but sometimes ineffective, this review focuses on chronobiological contributions to decrease the burden of hypertension and obesity in low- and middle-income groups of individuals. MEDLINE, Pubmed and SUMSearch sites (2001–2011) were used in the search strategy, together with the keywords: “antihypertensive drugs”; “arterial hypertension”; “circadian rhythms”; “obesity”; and “sleep quality”. Eighty-six articles were found and 50 articles from these were selected. A link between the circadian clock and hypertension has recently been described in animal models, using Clock-mutant mice that display metabolic syndrome. Experimental evidence clearly implicates circadian rhythms in the mechanisms that underlie the regulation of the blood pressure (BP) rhythm. Most clinical studies of BP focus on some pathological situation, such as hypertension, cardiovascular disease, sleep disorders, obesity, diabetes or pregnancy with blood biomarker alterations. However, epidemiological evidence for the role of circadian rhythms in hypertension has been lacking until recently. In Brazil, in an epidemiological, cross-sectional study, changed sleep quality and an earlier phase of mid-sleep were found in those using antihypertensive drugs. Moreover, some pharmacological studies support a circadian- and dose-dependent relationship in the use of antihypertensive drugs for the 24-h control of BP. In low- and middle-income areas, cost-effectiveness of any intervention is fundamental to the implementation of any kind of public-health policy. Therefore, improvements in diagnosis, effectiveness and implementing prevention measures to control the risk of disease are all necessary, and there is evidence that chronobiology has an important role to play. Consequently, it is important to provide guidelines to monitor BP to reduce cardiovascular risk that include chronobiological aspects of the problem