Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/321060
Type: TESE DIGITAL
Title: Estudo do envolvimento das isoformas epsilon-PKC e delta-PKC na diminuição da agregação plaquetária na sepse experimental
Title Alternative: Study of involvement of epsilon-PKC and delta-pkc isoforms in reduction of platelet aggregation in experimental sepsis
Author: Frade-Guanes, Jéssica Oliveira, 1992-
Advisor: Marcondes, Sisi, 1966-
Paschoal, Sisi Marcondes, 1966-
Abstract: Resumo: O lipopolissacarídeo (LPS) interage com diferentes células levando ao aumento da sintese e liberacao de varios mediadores inflamatorios como interleucinas e oxido nitrico (NO). Alem disso, o LPS leva ao aumento da geracao de especies reativas de oxigenio (EROs). O LPS tambem interage com plaquetas, consideradas hoje importantes celulas na inflamacao, entretanto, seus efeitos nas plaquetas sao muito controversos e pouco se sabe sobre as vias de sinalizacao envolvidas nos mesmos. A PKC, que possui varias isoformas em sua familia, e uma importante enzima para a modulacao da reatividade plaquetaria, bem como esta envolvida em varios efeitos desencadeados pelo LPS. Portanto, no presente trabalho decidimos investigar o papel da PKC¿Â e PKC¿Ã na modulacao da reatividade plaquetaria de ratos injetados com LPS. Para tanto, ratos foram injetados com salina ou LPS e apos 6h ou 48h foi determinada a agregacao induzida por ADP, bem como a ativacao de AKT, os niveis de GMPc e a fosforilacao do residuo Thr308 da VASP em plaquetas. Em alguns experimentos, as plaquetas foram pre-incubadas com os inibidores da PKC¿Â, rottlerin, ou da PKC¿Ã, SC-3095. A inibicao da PKC¿Ã reduz a agregacao de plaquetas de ratos injetados com salina e aumenta, discretamente, os niveis de GMPc intraplaquetario, entretanto, nao altera a ativacao de AKT ou a fosforilacao de VASP. Por outro lado, a inibicao da PKC¿Â nao altera nenhum dos efeitos avaliados no grupo salina. No grupo LPS 6h e possivel observar uma reducao da agregacao, acompanhada do aumento da atividade da AKT, aumento dos niveis de GMP e fosforilacao da VASP, sendo todos estes efeitos revertidos pela pre-incubacao das plaquetas com rottlerin. Ja no grupo LPS 48h observa-se uma reducao da agregacao plaquetaria acompanhada somente do aumento da fosforilacao de VASP. Neste grupo, a inibicao da PKC¿Ã reverte a fosforilacao de VASP, mas nao modifica o efeito inibitorio do LPS na agregacao plaquetaria. Portanto, concluimos que em ratos 6h apos injecao de LPS a via PKC¿Â-AKT-GMPc-PKG esta envolvida na inibicao da agregacao plaquetaria. Enquanto que, em 48h apos a injecao de LPS a inibicao da agregacao ocorre independentemente da PKC¿Â ou PKC¿Ã, bem como da ativacao de PKG

Abstract: Lipopolysaccharide (LPS) interacts with different cells leading to an increase of synthesis and release of many inflammatory mediators as interleukins and nitric oxide (NO). Moreover, LPS increases reactive oxygen species (ROS). LPS also may interact with platelets, today considered important cells in inflammation, however, its effects on these cells are very controversial and the signaling pathways have not been elucidate yet. PKC, that comprises several isoforms, is an important enzyme in platelet reactivity modulation, and is involved in several effects triggered by LPS. Therefore, in the present work we decided to investigate the role of PKCä and PKCå in the modulation of platelet reactivity in rats injected with LPS. Rats were injected with saline or LPS and after 6h or 48h the ADP-induced aggregation was determined as well as the activation of AKT, cGMP levels and the VASP phosphorylation on the residue Thr308 in platelets. In some experiments, platelets were pre-incubated with the inhibitors of PKCä or PKCå, rottlerin or sc-3095, respectively. Inhibition of PKCå reduces platelet aggregation of rats injected with saline and, quietly, increases intraplatelet cGMP levels, however, it does not modify the AKT activation or VASP phosphorylation. On the other side, PKCä inhibition does not change any effect evaluated in saline group. In the group LPS 6h is possible to observe a reduction on aggregation that is accompanied by increasing of AKT activity, an increase of cGMP levels and VASP phosphorylation, which are reversed by preincubation of the platelets with rottlerin. In the group LPS 48h observes a reduction of platelet aggregation followed only by increasing of VASP phosphorylation. In this group, the inhibition of PKCå reverses the phosphorylation of VASP, but does not modify the inhibitory effect of LPS on platelet aggregation. Therefore, we conclude that in the group LPS 6h, the inhibition of platelet aggregation occurs via PKCä-AKT-GMPc-PKG activation. While in 48h after LPS injection the inhibition of aggregation is independent of both PKCä and PKCå, as well as PKG activation
Subject: Plaquetas (Sangue)
Lipopolissacarideos
Proteina quinase C
Proteína quinase G
Editor: [s.n.]
Date Issue: 2016
Appears in Collections:FCM - Tese e Dissertação

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