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2.
J Cell Sci ; 132(6)2019 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-30814331

RESUMO

Intracellular parasites of the genus Leishmania are the causative agents of leishmaniasis. The disease is transmitted by the bite of a sand fly vector, which inoculates the parasite into the skin of mammalian hosts, including humans. During chronic infection the parasite lives and replicates inside phagocytic cells, notably the macrophages. An interesting, but overlooked finding, is that other cell types and even non-phagocytic cells have been found to be infected by Leishmania spp. Nevertheless, the mechanisms by which Leishmania invades such cells had not been previously studied. Here, we show that L. amazonensis can induce their own entry into fibroblasts independently of actin cytoskeleton activity, and, thus, through a mechanism that is distinct from phagocytosis. Invasion involves subversion of host cell functions, such as Ca2+ signaling and recruitment and exocytosis of host cell lysosomes involved in plasma membrane repair.This article has an associated First Person interview with the first author of the paper.


Assuntos
Membrana Celular/parasitologia , Fibroblastos/parasitologia , Leishmania mexicana , Lisossomos/parasitologia , Citoesqueleto de Actina/parasitologia , Animais , Sinalização do Cálcio , Linhagem Celular , Membrana Celular/metabolismo , Exocitose , Interações Hospedeiro-Parasita , Leishmania mexicana/metabolismo , Leishmania mexicana/parasitologia , Macrófagos/parasitologia , Camundongos , Fagocitose
3.
PLoS Negl Trop Dis ; 11(6): e0005657, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28586379

RESUMO

Trypanosoma cruzi enters host cells by subverting the mechanism of cell membrane repair. In this process, the parasite induces small injuries in the host cell membrane leading to calcium entry and lysosomal exocytosis, which are followed by compensatory endocytosis events that drive parasites into host cells. We have previously shown that absence of both LAMP-1 and 2, major components of lysosomal membranes, decreases invasion of T. cruzi into host cells, but the mechanism by which they interfere with parasite invasion has not been described. Here we investigated the role of these proteins in parasitophorous vacuole morphology, host cell lysosomal exocytosis, and membrane repair ability. First, we showed that cells lacking only LAMP-2 present the same invasion phenotype as LAMP1/2-/- cells, indicating that LAMP-2 is an important player during T. cruzi invasion process. Second, neither vacuole morphology nor lysosomal exocytosis was altered in LAMP-2 lacking cells (LAMP2-/- and LAMP1/2-/- cells). We then investigated the ability of LAMP-2 deficient cells to perform compensatory endocytosis upon lysosomal secretion, the mechanism by which cells repair their membrane and T. cruzi ultimately enters cells. We observed that these cells perform less endocytosis upon injury when compared to WT cells. This was a consequence of impaired cholesterol traffic in cells lacking LAMP-2 and its influence in the distribution of caveolin-1 at the cell plasma membrane, which is crucial for plasma membrane repair. The results presented here show the major role of LAMP-2 in caveolin traffic and membrane repair and consequently in T. cruzi invasion.


Assuntos
Membrana Celular/fisiologia , Fibroblastos/parasitologia , Proteínas de Membrana Lisossomal/metabolismo , Proteína 2 de Membrana Associada ao Lisossomo/metabolismo , Trypanosoma cruzi/fisiologia , Animais , Caveolina 1/genética , Caveolina 1/metabolismo , Endocitose , Fibroblastos/metabolismo , Fibroblastos/ultraestrutura , Regulação da Expressão Gênica/fisiologia , Proteína 2 de Membrana Associada ao Lisossomo/genética , Proteínas de Membrana Lisossomal/genética , Camundongos Knockout
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