Alteration of lipid order profile and permeability of plasma membranes from Trypanosoma cruzi epimastigotes grown in the presence of ketoconazole

Urbina, Julio A.; Vivas, Julio; Ramos, H.; Larralde, Gisela; Aguilar, Zuleima; Avilán, Luisana

doi:10.1016/0166-6851(88)90111-9

Cited by 44 publications

(26 citation statements)

References 38 publications

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“…Detection of a 98-kDa band in both the homogenate and cytoplasm, but not in the lysosomal and microsomal fractions, suggested this may be the underglycosylated HRG precursor contained in the endoplasmic reticulum. The smaller band detected in the homogenate and cytoplasm of both MDA-MB-231 and MCF-7 RV/H2 cells probably represents an artifact since MCF-7 cells do not produce HRG (35).…”

Section: Transmembrane Heregulin Is Bound To the Plasma Membrane Of Mmentioning

confidence: 99%

“…Plasma Membrane Isolation-Plasma membranes were isolated using standard cell fractionation techniques as described (35). In brief, 10 6 to 10 8 cells were harvested from subconfluent cultures using a 1ϫ solution of Versene (Life Technologies, Inc.), containing protease inhibitors as follows: 2 mM phenylmethylsulfonyl fluoride, 0.2 mg/ml trypsin inhibitor, 0.15 units/ml aprotinin, 1 mg/ml pepstatin A, 10 mM bestatin, 1 mM N-ethylmaleimide, 20 mM leupeptin, and 1 mM EDTA.…”

Section: Methodsmentioning

confidence: 99%

“…Purified plasma membrane fractions from both MDA-MB-231 cells and MCF-7 RV/H2 cells were obtained using conventional biochemical techniques (35), and assessed by examination with a transmission electron microscope (data not shown).…”

Section: Transmembrane Heregulin Is Bound To the Plasma Membrane Of Mmentioning

confidence: 99%

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The Transmembrane Heregulin Precursor Is Functionally Active

Aguilar

Slamon

2001

Journal of Biological Chemistry

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Section: Transmembrane Heregulin Is Bound To the Plasma Membrane Of Mmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The Transmembrane Heregulin Precursor Is Functionally Active

Aguilar

Slamon

2001

Journal of Biological Chemistry

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“…1). Azole drugs cause the accumulation of 14␣-methylsterols and decreased production of ergosterol (25).…”

mentioning

confidence: 99%

Potent Anti- Trypanosoma cruzi Activities of Oxidosqualene Cyclase Inhibitors

Buckner

Griffin

Wilson

et al. 2001

Antimicrob Agents Chemother

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Trypanosoma cruzi is the protozoan agent that causes Chagas' disease, a major health problem in Latin America. Better drugs are needed to treat infected individuals. The sterol biosynthesis pathway is a potentially excellent target for drug therapy against T. cruzi. In this study, we investigated the antitrypanosomal activities of a series of compounds designed to inhibit a key enzyme in sterol biosynthesis, oxidosqualene cyclase. This enzyme converts 2,3-oxidosqualene to the tetracyclic product, lanosterol. The lead compound, N-(4E,8E)-5,9, 13-trimethyl-4,8, 12-tetradecatrien-1-ylpyridinium, is an electron-poor aromatic mimic of a monocyclized transition state or high-energy intermediate formed from oxidosqualene. This compound and 27 related compounds were tested against mammalian-stage T. cruzi, and 12 inhibited growth by 50% at concentrations below 25 nM. The lead compound was shown to cause an accumulation of oxidosqualene and decreased production of lanosterol and ergosterol, consistent with specific inhibition of the oxidosqualene cyclase. The data demonstrate potent anti-T. cruzi activity associated with inhibition of oxidosqualene cyclase.

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“…2B, traces 2 and 3) is explained by the presence of exogenous cholesterol in promastigotes even after treatment with ketoconazole (Table 1). However, changes in membrane lipid packing (24) resulting from the ketoconazole-induced accumulation of 14-ot-methyl sterols (2, 11, 13) may also facilitate aqueous pore formation (Fig. 3) and subsequent membrane lysis.…”

Section: Discussionmentioning

confidence: 99%

Effect of ketoconazole on lethal action of amphotericin B on Leishmania mexicana promastigotes

Ramos

Saint-Pierre-Chazalet

Bolard

et al. 1994

Antimicrob Agents Chemother

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The effect of ergosterol depletion by ketoconazole on the leishmanicidal activity of the pore-forming antibiotic amphotericin B (AmB) was investigated. Leishmania mexicana promastigotes were lysed within minutes by the addition of micromolar concentrations of AmB (0.5 ,uM) but became insensitive to AmB after growth in the presence of ketoconazole (0.25 ,uM, 90 h). Lipid chromatographic analysis indicated that under such conditions, ketoconazole depleted the major Leishmania sterols, dehydroepisterol and ergosterol. Plasma membrane vesicles prepared from ketoconazole-treated promastigotes exhibited a much reduced enhancement of their salt permeability after the addition of AmB at concentrations as high as 5 ,uM. This finding clearly indicates that upon ketoconazole treatment, the capacity of pore formation by the antibiotic is substantially impaired. The reduction of desmethyl sterols by ketoconazole was accompanied by a significant increase of 14-a-methyl sterols, but exogenous cholesterol remained unchanged. This ability of Leishmania promastigotes to incorporate cholesterol from the external medium may explain why ketoconazole-treated cells exhibited a much decreased but significative response to AmB when they were exposed to high AmB concentrations (2.5 or 5.0 ,uM). Parallel measurements by using a fluorescence energy transfer method indicated that binding of AmB to ketoconazole-treated Leishmania promastigotes and heat-transformed leishmanias was also decreased but to different extents, a finding that may be related to the differences in their sterol content. The results obtained clearly indicate that the specific interaction of AmB with desmethyl sterols, such as dehydroepisterol, ergosterol, and even exogenous cholesterol, is an absolute requirement for the lethal action exerted by this polyene antibiotic on L. mexicana promastigotes.

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Alteration of lipid order profile and permeability of plasma membranes from Trypanosoma cruzi epimastigotes grown in the presence of ketoconazole

Cited by 44 publications

References 38 publications

The Transmembrane Heregulin Precursor Is Functionally Active

The Transmembrane Heregulin Precursor Is Functionally Active

Potent Anti- Trypanosoma cruzi Activities of Oxidosqualene Cyclase Inhibitors

Effect of ketoconazole on lethal action of amphotericin B on Leishmania mexicana promastigotes

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