Mesquita 2016 Thesis
|Mesquita Rodrigues C (2016) Efeito da depleção de ferro sobre Leishmania (Viannia) braziliensisuma análise ultraestrutural, proteômica e interação com matrizes de colágeno sintéticas. Doctoral Dissertation p210.|
Abstract: Leishmania protozoan parasites need iron to generate infective forms, colonize host cells and develop skin lesions in mice. Iron is also essential for the production of energy through the electron transport chain and the oxidative phosphorylation. This thesis aimed to analyze the effect of iron depletion on the cell growth, ultrastructure, protein expression and interaction of L. (V.) braziliensis with synthetic collagen matrices. Our results showed that iron depletion stops cell proliferation and impairs mitochondrial ultraestructure. This impairment is characterized by decreased activity of the electron transport chain complex IV which leads to both the reduction of oxygen consumption and the depolarization of mitochondrial membrane potential. However, while some parasites die due to mitochondrial dysfunction, others can resist nutritional stress and survive. It was observed that promastigotes increased mRNA expression of iron (LIT1) and heme (LHR1) transporters in iron depleted medium. The parasites also showed increased LIT1 and iron ferric reductase (LFR1) protein levels. Probably, the increased expression of transporters can enhance or maintain the intracellular concentrations of the metal, contributing to the parasites\2019 survival The increased expression of iron superoxide dismutase (FeSOD) mRNA should also play an important role on the parasites\2019 resistance to oxidative stress caused by iron depletion. During the interaction with collagen matrices it was observed that L. (V.) braziliensis promastigotes make contact with the fibers by both the flagellum and the cellular body, but their remodeling due to the action of parasites may start after longer periods of incubation. Also, the peptidases secreted in the conditioned medium and during the interaction with 3D collagen matrices exhibited identical profiles showing that collagen does not modulate the proteolytic profile of L. (V.) braziliensis. However, metalopeptidases probably contribute to matrix degradation because one was identified directly from the enzymatic halo suggesting that it is an active enzyme responsible for the degradation of the substrate.
Labels: MiParea: Respiration, mtDNA;mt-genetics, Exercise physiology;nutrition;life style, Pharmacology;toxicology
Preparation: Intact cells
Coupling state: ROUTINE Pathway: ROX HRR: Oxygraph-2k