Efeito de peptídeos derivados da proteina Delonix regia trypsin inhibitor (DrTI) sobre parâmetros da hemostasia e em modelos de trombose arterial
Data
2021-10-22
Autores
Souza, Daniel Alexandre de 
Orientadores
Oliva, Maria Luiza Vilela
Tipo
Dissertação de mestrado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
A hemostasia é definida como o complexo conjunto de processos bioquímicos que
tem como função manter o sangue fluído e dentro dos vasos. Este sistema envolve
uma variada classe de proteínas e processos interrelacionados e regulados de modo
a manter a hemostasia. Este sistema é sensível a pequenas mudanças que podem
levar a eventos severos, como hemorragia ou trombose. Diversos inibidores proteicos
provenientes de plantas têm sido estudados e caracterizados e entre els está o
Delonix regia trypsin inhibitor (DrTI). Esta proteína inibe serino-proteases (tripsina) e
enzimas diretamente envolvidas no processo de coagulação, como a calicreína
plasmática, fator XII e fator XI. Portanto, este trabalho objetiva avaliar o efeito de dois
novos peptídeos sintéticos derivados da estrutura primária do DrTI na coagulação e
em modelos de trombose arterial, para auxiliar no entendimento da patofisiologia
protrombótica assim como o desenvolvimento de novas terapias antritrombóticas.
Ambos os peptídeos agiram em parâmetros in vitro relacionados a trombose,
demonstrando resultados promissores, uma vez que prolongaram o tempo de
tromboplastina parcial ativado e inibiram a agregação plaquetária induzida por ADP e
ácido araquidônico. Em modelos in vivo, de trombose arterial induzida por lesão
fotoquímica e o estudo da interação de plaquetas-endotélio monitorada por
microscopia intravital, ambos os peptídeos em dose de 0,5 mg/kg prolongaram o
tempo para a oclusão arterial e modificaram o comportomaneto plaquetário,
demonstrando alto potencial biotecnológico.
Hemostasis is defined as a set of complex biochemical processes that keep the blood fluid and contained in the vessels. Different systems involving varied classes of proteins are interrelated and regulated to maintain hemostasis, a physiological process, sensitive to small changes that can cause high severe events such as hemorrhage and thrombosis. Over the years, several plant protein inhibitors with anticoagulant properties have been studied and characterized, among them is Delonix regia trypsin inhibitor (DrTI). This protein inhibits serine proteases (trypsin) and enzymes directly involved in the coagulation process such as plasma kallikrein, factor XII and factor XI. Therefore, this work aims to evaluate the effects of two new synthetic peptides, derived from the primary sequence the DrTI in coagulation and thrombosis models to assist the understanding of the mechanisms involved in the pathophysiology pro-thrombotic as well as in the development of new antithrombotic therapies. Both peptides acted on in vitro hemostasis-related parameters showing promising results since they prolonged the Partially Activated Thromboplastin Time (aPTT) and inhibited the platelet aggregation induced by ADP and arachidonic acid. In mice models, arterial thrombosis, induced by photochemical injury, and platelet-endothelial interactions monitored by intravital microscopy, both peptides at doses of 0.5 mg/kg extended the time of artery occlusion and modified the platelet aggregation pattern demonstrating the high biotechnological potential of both molecules.
Hemostasis is defined as a set of complex biochemical processes that keep the blood fluid and contained in the vessels. Different systems involving varied classes of proteins are interrelated and regulated to maintain hemostasis, a physiological process, sensitive to small changes that can cause high severe events such as hemorrhage and thrombosis. Over the years, several plant protein inhibitors with anticoagulant properties have been studied and characterized, among them is Delonix regia trypsin inhibitor (DrTI). This protein inhibits serine proteases (trypsin) and enzymes directly involved in the coagulation process such as plasma kallikrein, factor XII and factor XI. Therefore, this work aims to evaluate the effects of two new synthetic peptides, derived from the primary sequence the DrTI in coagulation and thrombosis models to assist the understanding of the mechanisms involved in the pathophysiology pro-thrombotic as well as in the development of new antithrombotic therapies. Both peptides acted on in vitro hemostasis-related parameters showing promising results since they prolonged the Partially Activated Thromboplastin Time (aPTT) and inhibited the platelet aggregation induced by ADP and arachidonic acid. In mice models, arterial thrombosis, induced by photochemical injury, and platelet-endothelial interactions monitored by intravital microscopy, both peptides at doses of 0.5 mg/kg extended the time of artery occlusion and modified the platelet aggregation pattern demonstrating the high biotechnological potential of both molecules.
Descrição
Citação
SOUZA, D.A. Efeito de peptídeos derivados da proteina Delonix regia trypsin inhibitor (DrTI) sobre parâmetros da hemostasia e em modelos de trombose arterial. São Paulo, 2021. 71 f. Dissertação (Mestrado em Biologia Molecular) - Escola Paulista de Medicina (EPM), Universidade Federal de São Paulo (UNIFESP). São Paulo, 2021.