Proteases secretadas por amostras clínicas e ambientais de Acanthamoeba de diferentes genótipos

• Ano de defesa: 2015
• Autor(a) principal: Elaine Isabella Soares Mesquita
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Minas Gerais; UFMG
• Palavras-chave em Português: Efeito citopático; Proteases; Acanthamoeba; Patogenicidade; Parasitologia; Protease; Doenças parasitárias; Ameba
• Link de acesso: http://hdl.handle.net/1843/BUBD-ARBQZ5

Amoebae of the genus Acanthamoeba are free-living organisms found in a wide range of environments, but eventually cause serious infections in humans, as granulomatous amoebic encephalitis and Acanthamoeba keratitis. Different species of Acanthamoeba have been described classified currently in more than 20 genotypes, based on 18S rDNA sequences. A factor related to the pathogenesis and virulence of Acanthamoeba is its ability to secrete proteases that seems to be involved in the pathogenesis of the infection. Some studies have assessed the quantitative and qualitative profile of these secretory products, seeking correlations with the virulence of different strains. The aim of this study was to perform a comparative analysis of the profile of secreted proteases for clinical and environmental samples of Acanthamoeba of different genotypes, and assess whether a change occurs after interaction with MDCK cells. Six clinical and environmental isolates of Acanthamoeba, belonging to genotypes T1 (one), T2 (one), T4 (three) and T11 (one), were grown in PYG medium at 32° C. Growth curves and cytopathic effect assay were performed, and trophozoites were incubated for 24 hours at 32°C to produce conditioned medium for zymography and azocasein assays. The conditioned medium was also obtained after the interaction with MDCK cells for three consecutive days. Zymography profiles varied among the isolates, that showed protease with molecular weight between 170 and 58 kDa, most identified as serine proteases. T1 genotype isolate obtained from environmental dust, showed quantitatively higher production of proteases than the others and a possible cisteinoprotease with high molecular weight (170 kDa). After interacting with MDCK cells, there was a change of zymography profile in all isolates, with the lifting of certain proteases and the emergence of others, including several low molecular weight (<60 kDa) and a protease that could be the MIP-133 (mannose-induced protease). The amount of proteases was lower in samples after interaction with MDCK cells. This study showed for the first time the protease profile of a T11 Acanthamoeba and a presumable cisteinoprotease of a T1 Acanthamoeba. Changes in proteases profile after interaction with MDCK cells indicated that Acanthamoeba can modulate pathogenicity factors, which can be an adaptive mechanism for its survival as a parasite. Keywords: Acanthamoeba, pathogenicity, proteases, CPE