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Abstract(s)
O plexo coroideu (CP) é uma estrutura altamente vascularizada localizada nas cavidades ventriculares cerebrais, que está envolvido na produção do líquido cefalorraquidiano (CSF) bem como na manutenção da sua composição química. Um estudo prévio, de microarrays de cDNA, no CP de rato, mostrou que existem uma série de vias de sinalização reguladas pelas hormonas sexuais, no CP de rato, entre as quais, a via de transdução olfativa. Um estudo subsequente revelou também que o CP expressa alguns receptores olfativos (ORs) e as proteínas da via de transdução olfativa, a adenil ciclase tipo 3 (AC3) e a subunidade a da proteína G específica do olfato (Gaolf). Assim, uma vez que a presença da via de sinalização olfativa já foi descrita noutros tecidos e dado que a sua função no CP pode ser extremamente relevante na manutenção da homeostasia cerebral, este trabalho teve como objetivo prosseguir com o estudo da sua expressão e funcionalização. Os resultados obtidos mostraram a expressão de um conjunto variado de ORs, nomeadamente o OR522, OR476, OR19, OR540, OR806, OR1382 e OR227 e da subunidade do canal nucleótido cíclico CNG2 nas células epiteliais do CP, concluindo-se assim que toda a maquinaria da via de transdução olfativa está presente no CP. Com o objetivo de analisar a resposta do CP a estímulos “olfativos”, estabeleceu-se um modelo in vitro, por otimização da técnica de Ca2+ imaging em culturas primárias de células epiteliais de CP (CPEC). Neste momento temos todas as condições otimizadas para prosseguir com os estudos funcionais, por forma a esclarecer a relevância funcional da via de transdução olfativa neste tecido. Um estudo realizado no nosso grupo de investigação, em paralelo com o presente trabalho, revelou que o CP responde eletrofisiologicamente às poliaminas, uma família de compostos químicos com um papel fundamental numa série de mecanismos celulares e bioquímicos, em todos os organismos vivos. Dada a importância fisiológica das poliaminas, impôs-se o estudo do seu metabolismo, no CP de rato. Começámos por analisar a expressão de vários genes da via biossintética e da via catabólica das poliaminas (OCD, SPMS, SPDS, AMD1, Azin1, SSAT e Oaz1), por RT-PCR, confirmando-se a sua expressão no CP. Além disso, por imunohistoquímica em explantes de CP, observou-se também expressão das proteínas OCD e SPSY, no citoplasma das células epiteliais do CP de rato. Com os resultados do presente trabalho, podemos então concluir que toda a maquinaria de transdução olfativa está presente no CP, e que este, para além de responder eletrofisiologicamente às poliaminas, está também envolvido no seu metabolismo.
The choroid plexus (CP) are highly vascularized structures, located in the brain ventricles, involved in the production of cerebrospinal fluid (CSF) as well as in the surveillance of its chemical composition. Previous studies, of cDNA microarrays in rat CP, allowed the identification of several signaling pathways regulated by sex hormones, including the olfactory transduction pathway. A subsequent study also revealed that CP expresses some olfactory receptors (ORs) and proteins of olfactory transduction pathway, namely the adenylate cyclase type 3 (AC3) and the subunit alpha of a smell specific G protein (Gaolf). As the presence of the olfactory signaling pathway has been described in other tissues, and because their function in CP should be extremely important in brain homeostasis sustenance, this project aimed to complete the study of their expression and functionalization. Our results showed the expression of a wide range of ORs, namely OR522, OR476, OR19, OR540, OR806, OR227 and OR1382 and the subunit of the cyclic nucleotide channel 2 (CNG2), in the epithelial cells of the CP, thus concluding that the whole machinery of the olfactory pathway is present in this structure. With the propose to analyze the responses of CP to “olfactory” stimuli, we optimized an in vitro model in CP epithelial cells (CPEC), for Ca2+ imaging. Right now, we have optimized the technique to proceed with the studies, in order to clarify the functional relevance of the olfactory transduction in this tissue. A study conducted in our research group, in parallel with the present work, revealed that the CP responds electrophysiologically to polyamines, a group of chemical compounds with a key role in a number of cellular and biochemical mechanisms in all living organisms. Due to the physiologic importance of polyamines we started the study of its metabolism in CP. The expression analysis of several genes of the biosynthetic and catabolic pathways of polyamines (OCD, SPMS, SPDS, AMD1, Azin1, SSAT and Oaz1) was performed by RT-PCR, and the results confirmed its expression in CP. Furthermore, by immunohistochemistry in CP explants, we also observed the presence of DCO and SPSY proteins in the cytoplasm of epithelial cells of rat CP. With all the results of this study, we conclude that the whole machinery of olfactory transduction is present in CP. Besides its electrophysiological response to polyamines, CP is also involved in polyamine metabolism.
The choroid plexus (CP) are highly vascularized structures, located in the brain ventricles, involved in the production of cerebrospinal fluid (CSF) as well as in the surveillance of its chemical composition. Previous studies, of cDNA microarrays in rat CP, allowed the identification of several signaling pathways regulated by sex hormones, including the olfactory transduction pathway. A subsequent study also revealed that CP expresses some olfactory receptors (ORs) and proteins of olfactory transduction pathway, namely the adenylate cyclase type 3 (AC3) and the subunit alpha of a smell specific G protein (Gaolf). As the presence of the olfactory signaling pathway has been described in other tissues, and because their function in CP should be extremely important in brain homeostasis sustenance, this project aimed to complete the study of their expression and functionalization. Our results showed the expression of a wide range of ORs, namely OR522, OR476, OR19, OR540, OR806, OR227 and OR1382 and the subunit of the cyclic nucleotide channel 2 (CNG2), in the epithelial cells of the CP, thus concluding that the whole machinery of the olfactory pathway is present in this structure. With the propose to analyze the responses of CP to “olfactory” stimuli, we optimized an in vitro model in CP epithelial cells (CPEC), for Ca2+ imaging. Right now, we have optimized the technique to proceed with the studies, in order to clarify the functional relevance of the olfactory transduction in this tissue. A study conducted in our research group, in parallel with the present work, revealed that the CP responds electrophysiologically to polyamines, a group of chemical compounds with a key role in a number of cellular and biochemical mechanisms in all living organisms. Due to the physiologic importance of polyamines we started the study of its metabolism in CP. The expression analysis of several genes of the biosynthetic and catabolic pathways of polyamines (OCD, SPMS, SPDS, AMD1, Azin1, SSAT and Oaz1) was performed by RT-PCR, and the results confirmed its expression in CP. Furthermore, by immunohistochemistry in CP explants, we also observed the presence of DCO and SPSY proteins in the cytoplasm of epithelial cells of rat CP. With all the results of this study, we conclude that the whole machinery of olfactory transduction is present in CP. Besides its electrophysiological response to polyamines, CP is also involved in polyamine metabolism.
Description
Keywords
Líquido Cefalorraquidiano Plexo Coroideu Poliaminas Recetores Olfativos Transdução Olfativa