A semi-synthetic neolignan derivative from dihydrodieugenol B selectively affects the bioenergetic system of Leishmania infantum and inhibits cell division / A semi-synthetic neolignan derivative from dihydrodieugenol B selectively affects the bioenergetic system of Leishmania infantum and inhibits cell division

Leishmaniasis is a neglected disease that affects more than 12 million people, with a limited therapy. plant-derived natural products represent a useful source of anti-protozoan prototypes. In this work, four derivatives were prepared from neolignans isolated from the Brazilian plant Nectandra leucantha, and their effects against intracellular amastigotes of Leishmania (L.) infantum evaluated in vitro. IC50 values between 6 and 35 µM were observed and in silico predictions suggested good oral bioavailability, no pAINs similarities, and ADMet risks typical of lipophilic compounds. the most selective (sI > 32) compound was chosen for lethal action and immunomodulatory studies. this compound caused a transient depolarization of the plasma membrane potential and induced an imbalance of intracellular Ca2+, possibly resulting in a mitochondrial impairment and leading to a strong depolarization of the membrane potential and decrease of ATP levels. The derivative also interfered with the cell cycle of Leishmania, inducing a programmed cell death-like mechanism and affecting DNA replication. Further immunomodulatory studies demonstrated that the compound eliminates amastigotes via an independent activation of the host cell, with decrease levels of IL-10, TNF and MCP-1. Additionally, this derivative caused no hemolytic effects in murine erythrocytes and could be considered promising for future lead studies.

Mammalian cell invasion and intracellular trafficking by Trypanosoma cruzi infective forms

O agente etiológico da doença de Chagas, Trypanosoma cruzi, ocorre como cepas ou isolados que podem ser agrupados em duas grandes linhagens filogenéticas: T. cruzi I associada ao ciclo silvestre e T. cruzi II ligada à doença humana. No hospedeiro mamífero o parasita tem que invadir células, e vários estudos relacionam as formas flageladas tripomastigotas neste processo. Diferentes componentes de superfície dos parasitas e alguns dos respectivos receptores foram identificados. Em nosso trabalho temos procurado compreender como amastigotas, que normalmente são encontrados crescendo no citoplasma, podem invadir células de mamíferos com infectividade comparável às dos tripomastigotas. Encontramos diferenças nas respostas celulares induzidas por amastigotas e tripomastigotas em relação a componentes de citoesqueleto e projeções de membrana ricas em actina. Amastigotas de cepas de T. cruzi I gerados extracelularmente, podem apresentar infectividade maior que tripomastigotas metacíclicos para linhagens celulares e células com expressão alterada em diferentes classes de componentes celulares. Células albergando a bactéria Coxiella burnetii tem nos permitido obter novos enfoques sobre as propriedades de tráfego intracelular das diferentes formas infectivas do T. cruzi, revelando requerimentos inesperados para o parasita transitar entre seu vacúolo parasitóforo até seu destino final no citoplasma da célula hospedeira.