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Protective role of the dynamin inhibitor Dynasore against the cholesterol-dependent cytolysin of Trueperella pyogenes.

ABSTRACT: The virulence of many Gram-positive bacteria depends on cholesterol-dependent cytolysins (CDCs), which form pores in eukaryotic cell plasma membranes. Pyolysin (PLO) from Trueperella pyogenes provided a unique opportunity to explore cellular responses to CDCs because it does not require thiol activation. Sublytic concentrations of PLO stimulated phosphorylation of MAPK ERK and p38 in primary stromal cells, and induced autophagy as determined by protein light-chain 3B cleavage. Although, inhibitors of MAPK or autophagy did not affect PLO-induced cytolysis. However, 10 ?M 3-hydroxynaphthalene-2-carboxylic acid-(3,4-dihydroxybenzylidene)-hydrazide (Dynasore), a dynamin guanosine 5'-triphosphatase inhibitor, protected stromal cells against PLO-induced cytolysis as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (85 ± 17% versus 50 ± 9% cell viability), measuring extracellular ATP, and kinetic assays. This was a generalized mechanism because Dynasore also protected HeLa cells against streptolysin O. Furthermore, the effect was reversible, with stromal cell sensitivity to PLO restored within 30 minutes of Dynasore removal. The protective effect of Dynasore was not conferred by dynamin inhibition, induction of ERK phosphorylation, or Dynasore binding to PLO. Rather, Dynasore reduced cellular cholesterol and disrupted plasma membrane lipid rafts, similar to positive control methyl-?-cyclodextrin. Dynasore is a tractable tool to explore the complexity of cholesterol homeostasis in eukaryotic cells and to develop strategies to counter CDCs.

SUBMITTER: Preta G

PROVIDER: S-EPMC4396600 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature

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Protective role of the dynamin inhibitor Dynasore against the cholesterol-dependent cytolysin of Trueperella pyogenes.

Preta Giulio G Lotti Virginia V Cronin James G JG Sheldon I Martin IM

FASEB journal : official publication of the Federation of American Societies for Experimental Biology 20141230 4

The virulence of many Gram-positive bacteria depends on cholesterol-dependent cytolysins (CDCs), which form pores in eukaryotic cell plasma membranes. Pyolysin (PLO) from Trueperella pyogenes provided a unique opportunity to explore cellular responses to CDCs because it does not require thiol activation. Sublytic concentrations of PLO stimulated phosphorylation of MAPK ERK and p38 in primary stromal cells, and induced autophagy as determined by protein light-chain 3B cleavage. Although, inhibito ...[more]

PMID: 25550455

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Project description:BackgroundTrypanosoma cruzi is an intracellular parasite that, like some other intracellular pathogens, targets specific proteins of the host cell vesicular transport machinery, leading to a modulation of host cell processes that results in the generation of unique phagosomes. In mammalian cells, several molecules have been identified that selectively regulate the formation of endocytic transport vesicles and the fusion of such vesicles with appropriate acceptor membranes. Among these, the GTPase dynamin plays an important role in clathrin-mediated endocytosis, and it was recently found that dynamin can participate in a phagocytic process.Methodology/principal findingsWe used a compound called dynasore that has the ability to block the GTPase activity of dynamin. Dynasore acts as a potent inhibitor of endocytic pathways by blocking coated vesicle formation within seconds of its addition. Here, we investigated whether dynamin is involved in the entry process of T. cruzi in phagocytic and non-phagocytic cells by using dynasore. In this aim, peritoneal macrophages and LLC-MK2 cells were treated with increasing concentrations of dynasore before interaction with trypomastigotes, amastigotes or epimastigotes. We observed that, in both cell lines, the parasite internalization was drastically diminished (by greater than 90% in LLC-MK2 cells and 70% in peritoneal macrophages) when we used 100 microM dynasore. The T. cruzi adhesion index, however, was unaffected in either cell line. Analyzing these interactions by scanning electron microscopy and comparing peritoneal macrophages to LLC-MK2 cells revealed differences in the stage at which cell entry was blocked. In LLC-MK2 cells, this blockade is observed earlier than it is in peritoneal macrophages. In LLC-MK2 cells, the parasites were only associated with cellular microvilli, whereas in peritoneal macrophages, trypomastigotes were not completely engulfed by a host cell plasma membrane.Conclusions/significanceTaken together our results demonstrate that dynamin is an essential molecule necessary for cell invasion and specifically parasitophorous vacuole formation by host cells during interaction with Trypanosoma cruzi.

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Protective role of the dynamin inhibitor Dynasore against the cholesterol-dependent cytolysin of Trueperella pyogenes.

Publications

Protective role of the dynamin inhibitor Dynasore against the cholesterol-dependent cytolysin of Trueperella pyogenes.

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