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Updated: Mar 19, 2026
Establishment of an In vitro System to Study Intracellular Behavior of Candida glabrata in Human THP-1 Macrophages
Published on: December 10, 2013
Novel cell-based in vitro screen to identify small-molecule inhibitors against intracellular replication of
Sweta Samantaray1, Joao N Correia1, Mariam Garelnabi1
1Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, UK.
Abstract:
The fungal pathogen Cryptococcus neoformans poses a major threat to immunocompromised patients and is a leading killer of human immunodeficiency virus (HIV)-infected patients worldwide. Cryptococci are known to manipulate host macrophages and can either remain latent or proliferate intracellularly within the host phagocyte, a favourable niche that also renders them relatively insensitive to antifungal agents. Here we report an attempt to address this limitation by using a fluorescence-based drug screening method to identify potential inhibitors of intracellular proliferation of C. neoformans. The Prestwick Chemical Library(®) of FDA-approved small molecules was screened for compounds that limit the intracellular replication of a fluorescently-tagged C. neoformans reference strain (H99-GFP) in macrophages. Preliminary screening revealed 19 of 1200 compounds that could significantly reduce intracellular growth of the pathogen. Secondary screening and host cell cytotoxicity assays highlighted fendiline hydrochloride as a potential drug candidate for the development of future anticryptococcal therapies. Live cell imaging demonstrated that this Ca(2+) channel blocker strongly enhanced phagosome maturation in macrophages leading to improved fungal killing and reduced intracellular replication. Whilst the relatively high dose of fendiline hydrochloride required renders it unfit for clinical deployment against cryptococcosis, this study highlights a novel approach for identifying new lead compounds and unravels a pharmacologically promising scaffold towards the development of novel antifungal therapies for this neglected disease.
Insights
Researchers screened FDA-approved drugs to find treatments for Cryptococcus neoformans infections in immunocompromised patients. Fendiline hydrochloride showed promise by enhancing macrophage killing of the fungus.
Area of Science:
- Mycology
- Infectious Diseases
- Pharmacology
Background:
- Cryptococcus neoformans is a fungal pathogen causing life-threatening infections, especially in HIV-positive individuals.
- Intracellular proliferation within macrophages offers a protective niche for C. neoformans, limiting antifungal efficacy.
Purpose of the Study:
- To identify novel inhibitors of intracellular C. neoformans proliferation using a fluorescence-based drug screening approach.
- To evaluate potential therapeutic candidates for cryptococcosis, a neglected fungal disease.
Main Methods:
- Screening of the Prestwick Chemical Library (1200 FDA-approved small molecules) against a fluorescently tagged C. neoformans strain (H99-GFP) in macrophages.
- Secondary screening and cytotoxicity assays to identify effective and safe compounds.
- Live cell imaging to elucidate the mechanism of action of promising drug candidates.
Main Results:
- 19 out of 1200 compounds significantly reduced intracellular C. neoformans growth.
- Fendiline hydrochloride demonstrated potent anticryptococcal activity by enhancing phagosome maturation in macrophages.
- This led to improved fungal killing and reduced intracellular replication, although high doses were required.
Conclusions:
- A novel fluorescence-based drug screening method effectively identified inhibitors of intracellular fungal pathogens.
- Fendiline hydrochloride, a Ca(2+) channel blocker, represents a promising scaffold for developing new antifungal therapies against cryptococcosis.
- Further optimization is needed to overcome dose limitations for clinical application.
