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Miltefosine Has a Postantifungal Effect and Induces Apoptosis in Cryptococcus Yeasts. Antimicrob Agents Chemother 2018; 62:AAC.00312-18. [PMID: 29844051 DOI: 10.1128/aac.00312-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/18/2018] [Indexed: 02/04/2023] Open
Abstract
Cryptococcus spp. are common opportunistic fungal pathogens, particularly in HIV patients. The approved drug miltefosine (MFS) has potential as an alternative antifungal against cryptococcosis; however, the mechanism of action of MFS in Cryptococcus is poorly understood. Here, we examined the effects of MFS on C. neoformans and C. gattii yeasts (planktonic and biofilm lifestyles) to clarify its mechanism of action. MFS presented inhibitory and fungicidal effects against planktonic Cryptococcus cells, with similar activities against dispersion biofilm cells, while sessile biofilm cells were less sensitive to MFS. Interestingly, MFS had postantifungal effect on Cryptococcus, with a proliferation delay of up to 8.15 h after a short exposure to fungicidal doses. MFS at fungicidal concentrations increased the plasma membrane permeability, likely due to a direct interaction with ergosterol, as suggested by competition assays with exogenous ergosterol. Moreover, MFS reduced the mitochondrial membrane potential, increased reactive oxygen species (ROS) production, and induced DNA fragmentation and condensation, all of which are hallmarks of apoptosis. Transmission electron microscopy analysis showed that MFS-treated yeasts had a reduced mucopolysaccharide capsule (confirmed by morphometry with light microscopy), plasma membrane irregularities, mitochondrial swelling, and a less conspicuous cell wall. Our results suggest that MFS increases the plasma membrane permeability in Cryptococcus via an interaction with ergosterol and also affects the mitochondrial membrane, eventually leading to apoptosis, in line with its fungicidal activity. These findings confirm the potential of MFS as an antifungal against C. neoformans and C. gattii and warrant further studies to establish clinical protocols for MFS use against cryptococcosis.
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Pereira de Sá N, Lino CI, Fonseca NC, Borelli BM, Ramos JP, Souza-Fagundes EM, Rosa CA, Santos DA, Barbosa de Oliveira R, Johann S. Thiazole compounds with activity against Cryptococcus gattii and Cryptococcus neoformans in vitro. Eur J Med Chem 2015; 102:233-42. [PMID: 26276437 DOI: 10.1016/j.ejmech.2015.07.032] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 06/08/2015] [Accepted: 07/16/2015] [Indexed: 11/29/2022]
Abstract
Human cryptococcosis can occur as a primary or opportunistic infection and develop as an acute, subacute, or chronic, systemic infection involving different host organs. We evaluated the antifungal activity of thirteen compounds against Cryptococcus gattii and Cryptococcus neoformans in vitro, by assessing the toxicity of the compounds showing the greatest antifungal activity in VERO cells and murine macrophages. From these results, four compounds were considered promising for further studies because they displayed low cytotoxicity and significant antifungal activity. The heterocyclic compounds 1b, 1c, 1d, and 1m have antifungal activity levels between that of amphotericin B and fluconazole in vitro. The death curve of Cryptococcus spp. treated with these four compounds was similar to the curve obtained for amphotericin B, in that we observed a significant reduction in cell viability within the first 24 h of treatment. Additionally, we found that there was no effect when these compounds were combined with amphotericin and fluconazole, except for 1c, which antagonized the effect of amphotericin B against C. gattii, also reflected in the reduction of the post-antifungal effect (PAFE); however, this interaction did not alter the ergosterol content. The results shown in this paper reveal the discovery of novel thiazole compounds, which are easy to synthesize, and with potentially exhibit antifungal activity, and display low cytotoxicity in normal mammalian cells. These compounds can be used as prototypes for the design of new antifungal drugs against C. gattii and C. neoformans.
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Affiliation(s)
- Nívea Pereira de Sá
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Cleudiomar Inácio Lino
- Departamento de Produtos Farmacêuticos, Faculdade de Farmácia da UFMG, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Nayara Cristina Fonseca
- Departamento de Produtos Farmacêuticos, Faculdade de Farmácia da UFMG, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Beatriz Martins Borelli
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Jonas Pereira Ramos
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Elaine Maria Souza-Fagundes
- Departamento de Fisiologia e Biofísica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Carlos Augusto Rosa
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Daniel Assis Santos
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Renata Barbosa de Oliveira
- Departamento de Produtos Farmacêuticos, Faculdade de Farmácia da UFMG, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Susana Johann
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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Ellepola ANB. Amphotericin B-induced in vitro postantifungal effect on Candida species of oral origin. Med Princ Pract 2012; 21:442-6. [PMID: 22678101 DOI: 10.1159/000339080] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/04/2012] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVE The aim of this investigation was to measure the postantifungal effect (PAFE) of 6 different oral Candida species following exposure to amphotericin B. MATERIALS AND METHODS Five oral isolates each of Candida albicans, Candida tropicalis, Candida krusei, Candida parapsilosis, Candida glabrata and Candida guilliermondii (total of 30 isolates) were examined for the presence of PAFE after 1 h of exposure to the minimum inhibitory concentration of amphotericin B. The PAFE was determined as the difference in time (hours) required for the growth of the drug-free control and the drug-exposed test cultures to increase to 0.05 absorbance level following removal of amphotericin B. RESULTS The mean duration of amphotericin B-induced PAFE was lowest for C. albicans (5.91 ± 0.31 h) and greatest for C. parapsilosis (12.72 ± 0.11 h), while C. guilliermondii (8.32 ± 0.33 h), C. glabrata (8.43 ± 0.21 h), C. krusei (9.68 ± 0.23 h) and C. tropicalis (10.98 ± 0.18 h) elicited intermediate values. CONCLUSION Even a limited exposure to sublethal concentrations of amphotericin B suppressed growth of Candida species of oral origin. The significant variation in amphotericin B-induced PAFE amongst different Candida species may have clinical implications in terms of amphotericin B regimens used in the management of oral candidiasis.
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Affiliation(s)
- A N B Ellepola
- Department of Bioclinical Sciences, Faculty of Dentistry, Health Sciences Center, Kuwait University, Jabriya, Kuwait.
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Snell SB, Foster TH, Haidaris CG. Miconazole induces fungistasis and increases killing of Candida albicans subjected to photodynamic therapy. Photochem Photobiol 2011; 88:596-603. [PMID: 22077904 DOI: 10.1111/j.1751-1097.2011.01039.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cutaneous and mucocutaneous Candida infections are considered to be important targets for antimicrobial photodynamic therapy (PDT). Clinical application of antimicrobial PDT will require strategies that enhance microbial killing while minimizing damage to host tissue. Increasing the sensitivity of infectious agents to PDT will help achieve this goal. Our previous studies demonstrated that raising the level of oxidative stress in Candida by interfering with fungal respiration increased the efficiency of PDT. Therefore, we sought to identify compounds in clinical use that would augment the oxidative stress caused by PDT by contributing to reactive oxygen species (ROS) formation themselves. Based on the ability of the antifungal miconazole to induce ROS in Candida, we tested several azole antifungals for their ability to augment PDT in vitro. Although miconazole and ketoconazole both stimulated ROS production in Candida albicans, only miconazole enhanced the killing of C. albicans and induced prolonged fungistasis in organisms that survived PDT using the porphyrin TMP-1363 and the phenothiazine methylene blue as photosensitizers. The data suggest that miconazole could be used to increase the efficacy of PDT against C. albicans, and its mechanism of action is likely to be multifactorial.
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Affiliation(s)
- Sara B Snell
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, USA
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Barasch A, Griffin AV. Miconazole revisited: new evidence of antifungal efficacy from laboratory and clinical trials. Future Microbiol 2008; 3:265-9. [DOI: 10.2217/17460913.3.3.265] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the past 40 years imidazoles have been used extensively in medicine for their antifungal properties. All members of the azole antifungal family inhibit ergosterol biosynthesis. However, the discovery of an additional fungicidal mode of action for miconazole has drawn renewed attention to this compound. In this article we review recent evidence of mechanistic efficacy, as well as clinical trial results of miconazole in new topical formulations.
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Affiliation(s)
- Andrei Barasch
- Dept of Diagnostic Sciences, University of Alabama at Birmingham, SDB 111, 1530 3rd Avenue S Birmingham, AL 35294-0007, USA
| | - Andreea Voinea Griffin
- Dept of Diagnostic Sciences, University of Alabama at Birmingham, SDB 111, 1530 3rd Avenue S Birmingham, AL 35294-0007, USA
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