Leishmania sp.:Growth and Survival Are Impaired by Ion Channel Blockers

Ponte-Sucre, Alicia; Campos, Yelitza; Fernández, M. Cristina; Moll, Heidrun; Mendoza-León, Alexis

doi:10.1006/expr.1998.4200

Cited by 29 publications

(32 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After removal of extracellular parasites by thorough rinsing with fresh complete medium, cells were incubated for a further 48 h in the presence of the test compound over a concentration range of 0.0001 to 10 M. DMSO-treated and untreated cultures served as controls. Intracellular parasites were quantified by staining with acridine orange (Sigma-Aldrich) and ethidium bromide (Sigma-Aldrich) and analyzed by fluorescence microscopy (emission/excitation wavelengths, 495/450 nm), as described previously (29). All experiments were repeated three times.…”

Section: Methodsmentioning

confidence: 99%

Bis-Acridines as Lead Antiparasitic Agents: Structure-Activity Analysis of a Discrete Compound Library In Vitro

Caffrey

Steverding

Swenerton

et al. 2007

Antimicrob Agents Chemother

Self Cite

View full text Add to dashboard Cite

Parasitic diseases are of enormous public health significance in developing countries-a situation compounded by the toxicity of and resistance to many current chemotherapeutics. We investigated a focused library of 18 structurally diverse bis-acridine compounds for in vitro bioactivity against seven protozoan and one helminth parasite species and compared the bioactivities and the cytotoxicities of these compounds toward various mammalian cell lines. Structure-activity relationships demonstrated the influence of both the bisacridine linker structure and the terminal acridine heterocycle on potency and cytotoxicity. The bioactivity of polyamine-linked acridines required a minimum linker length of approximately 10 Å. Increasing linker length resulted in bioactivity against most parasites but also cytotoxicity toward mammalian cells. N alkylation, but less so N acylation, of the polyamine linker ameliorated cytotoxicity while retaining bioactivity with 50% effective concentration (EC 50 ) values similar to or better than those measured for standard drugs. Substitution of the polyamine for either an alkyl or a polyether linker maintained bioactivity and further alleviated cytotoxicity. Polyamine-linked compounds in which the terminal acridine heterocycle had been replaced with an aza-acridine also maintained acceptable therapeutic indices. The most potent compounds recorded low-to mid-nanomolar EC 50 values against Plasmodium falciparum and Trypanosoma brucei; otherwise, low-micromolar potencies were measured. Importantly, the bioactivity of the library was independent of P. falciparum resistance to chloroquine. Compound bioactivity was a function of neither the potential to bis-intercalate DNA nor the inhibition of trypanothione reductase, an important drug target in trypanosomatid parasites. Our approach illustrates the usefulness of screening focused compound libraries against multiple parasite targets. Some of the bis-acridines identified here may represent useful starting points for further lead optimization.

show abstract

Section: Methodsmentioning

confidence: 99%

Bis-Acridines as Lead Antiparasitic Agents: Structure-Activity Analysis of a Discrete Compound Library In Vitro

Caffrey

Steverding

Swenerton

et al. 2007

Antimicrob Agents Chemother

Self Cite

View full text Add to dashboard Cite

show abstract

“…The average number of parasites per infected DC was determined by counting 100 to 200 immature DC (6 days) or mature DC (10 days) at 24 and 72 h after pulse infection with stationary-phase promastigotes for 30 min. The parasite load was quantified by staining with acridine orange (Sigma-Aldrich) and ethidium bromide (Sigma-Aldrich) and analysis by fluorescence microscopy at 495 nm (26).…”

Section: Methodsmentioning

confidence: 99%

Biogenesis of Leishmania major -Harboring Vacuoles in Murine Dendritic Cells

et al. 2006

Self Cite

View full text Add to dashboard Cite

In mammalian hosts, Leishmania sp. parasites are obligatory intracellular organisms that invade macrophages and dendritic cells (DC), where they reside in endocytic organelles termed parasitophorous vacuoles (PV). Most of the present knowledge of the characteristics of PV harboring Leishmania sp. is derived from studies with infected macrophages. Since DC play a key role in host resistance to leishmaniasis, there is a need to understand the properties and biogenesis of PV in Leishmania sp.-infected DC. Therefore, we determined the acquisition of endosomal and lysosomal molecules by Leishmania major-containing compartments in DC at different maturation stages, using fluorescence labeling and confocal microscopy. The results show that newly formed phagosomes in DC rapidly develop into late endosomal compartments. However, the small GTPase Rab7, which regulates late fusion processes, was found only in PV of mature bone marrow-derived DC (BMDC); it was absent in immature BMDC, suggesting an arrest of their PV biogenesis at the stage of late endosomes. Indeed, fusion assays with endocytic tracers demonstrated that the fusion activity of L. majorharboring PV toward lysosomes is higher in mature BMDC than in immature BMDC. The inhibition of PV-lysosome fusion in DC is dependent upon the viability and life cycle stage of the parasite, because live promastigotes blocked the fusion almost completely, whereas killed organisms and amastigotes induced a considerable level of fusion activity. The differences in the fusion competences of immature and mature DC may be relevant for their distinct functional activities in the uptake, transport, and presentation of parasite antigens.Protozoan parasites of the genus Leishmania are transmitted to mammalian hosts by phlebotomine sand flies. During the blood meal of an infected insect, the flagellated promastigote form gains access to host tissues and is rapidly phagocytosed, predominantly by macrophages in which the parasites transform into amastigotes devoid of the external flagellum. This process occurs within organelles termed parasitophorous vacuoles (PV). Amastigotes are well adapted to the conditions in the PV, allowing them to survive and multiply intracellularly (7).A critical part of the chain of events leading to degradation and death of intracellular microorganisms, including Leishmania sp. parasites, in macrophages is phagolysosome biogenesis. Newly formed phagosomes are unable to digest their contents and must therefore undergo a complex maturation process, which is driven by a series of sequential fusion events between phagosomes and early endosomes, late endosomes, and lysosomes (1, 10, 14). Each phagosome maturation stage is characterized by specific compartmental markers, such as the early endosomal markers CD71 and Rab4, the late endosomal markers Rab7 and CD68, and the late endosomal/lysosomal glycoproteins LAMP-1 and LAMP-2. These steps lead to the formation of the phagolysosome, an acidic compartment displaying the harsh and lytic environment needed to destroy mi...

show abstract

“…These authors described two anionic currents but suggested the presence of other channels. Their finding is consistent with Leishmania anion fluxes involved in parasite survival (Ponte-Sucre et al, 1998) and electron transport by redox enzymes (Bera et al, 2005). We have been interested in the study of ion channels of Leishmania, with a particular emphasis on chloride channels, assuming that these molecules are relevant in parasite survival and are an adaptation to the acidic pH of the PV.…”

Section: Leishmania Plasma Membranementioning

confidence: 71%

Electrical Membrane Properties in the Model Leishmania-Macrophage

Camacho¹

2012

Patch Clamp Technique

View full text Add to dashboard Cite

Leishmania sp.:Growth and Survival Are Impaired by Ion Channel Blockers

Cited by 29 publications

References 39 publications

Bis-Acridines as Lead Antiparasitic Agents: Structure-Activity Analysis of a Discrete Compound Library In Vitro

Bis-Acridines as Lead Antiparasitic Agents: Structure-Activity Analysis of a Discrete Compound Library In Vitro

Biogenesis of Leishmania major -Harboring Vacuoles in Murine Dendritic Cells

Electrical Membrane Properties in the Model Leishmania-Macrophage

Contact Info

Product

Resources

About