Proliferation of Toxoplasma gondii Suppresses Host Cell Autophagy

Title
Proliferation of Toxoplasma gondii Suppresses Host Cell Autophagy
Author
류재숙
Keywords
Toxoplasma gondii; Autophagy; Rapamycin; LC3 II; Beclin 1
Issue Date
2013-06
Publisher
KOREAN SOC PARASITOLOGY
Citation
The Korean journal of parasitology, 2013, 51(3), P.279-287
Abstract
Autophagy is a process of cytoplasmic degradation of endogenous proteins and organelles. Although its primary role is protective, it can also contribute to cell death. Recently, autophagy was found to play a role in the activation of host defense against intracellular pathogens. The aims of our study was to investigate whether host cell autophagy influences Toxoplasma gondii proliferation and whether autophagy inhibitors modulate cell survival. HeLa cells were infected with T. gondii with and without rapamycin treatment to induce autophagy. Lactate dehydrogenase assays showed that cell death was extensive at 36-48 hr after infection in cells treated with T. gondii with or without rapamycin. The autophagic markers, LC3 II and Beclin 1, were strongly expressed at 18-24 hr after exposure as shown by Western blotting and RT-PCR. However, the subsequent T. gondii proliferation suppressed autophagy at 36 hr post-infection. Pre-treatment with the autophagy inhibitor, 3-methyladenine (3-MA), down-regulated LC3 II and Beclin 1. The latter was also down-regulated by calpeptin, a calpain inhibitor. Monodansyl cadaverine (MDC) staining detected numerous autophagic vacuoles (AVs) at 18 hr post-infection. Ultrastructural observations showed T. gondii proliferation in parasitophorous vacuoles (PVs) coinciding with a decline in the numbers of AVs by 18 hr. FACS analysis failed to confirm the presence of cell apoptosis after exposure to T. gondii and rapamycin. We concluded that T. gondii proliferation may inhibit host cell autophagy and has an impact on cell survival.
URI
http://parasitol.kr/journal/view.php?doi=10.3347/kjp.2013.51.3.279http://hdl.handle.net/20.500.11754/45081
ISSN
0023-4001
DOI
10.3347/kjp.2013.51.3.279
Appears in Collections:
COLLEGE OF MEDICINE[S](의과대학) > MEDICINE(의학과) > Articles
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