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Ben Abid F, Abdel Rahman S Al Soub H, Al Maslamani M, Ibrahim WH, Ghazouani H, Al-Khal A, Taj-Aldeen S. Incidence and clinical outcome of Cryptococcosis in a nation with advanced HIV surveillance program. Aging Male 2020; 23:1125-1130. [PMID: 31741419 DOI: 10.1080/13685538.2019.1692198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND Cryptococcosis is a major opportunistic invasive mycosis that mostly affects immunocompromised patients. METHODS This was an observational study of all culture-confirmed cases of cryptococcosis conducted in the State of Qatar from January 2005 to December 2016. Cryptococcus fungi were identified using Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). RESULTS Fourteen culture-confirmed cases of cryptococcosis were identified during the study period. Four patients had a Human Immunodeficiency Virus (HIV) infection with low CD4 count and five were receiving immunosuppressant medications. The rest of the patients were apparently immuno-competent. The central nervous system was the most common site of infection (57%) followed by bloodstream infection (36%) and pneumonia (14%). One patient had a cryptococcal scrotal infection. Twelve isolates were Cryptococcus neoformans and 2 were Cryptococcus laurentii. All isolates were within the wild type ECV values to amphotericin B and fluconazole. Only 2 patients with bloodstream infection (HIV negative) died. The rest were cured of the infection. CONCLUSION Cryptococcosis is a rare fungal disease in the State of Qatar, mostly diagnosed in Asian immigrants. The central nervous system is the most common site of infection. The presence of the fungus in the blood carries a high mortality.
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Affiliation(s)
- Fatma Ben Abid
- Infectious Disease Department, Hamad Medical Corp, Medicine, Hamad General Hospital-HMC, Doha, Qatar
| | | | - Muna Al Maslamani
- Infectious Diseases, Hamad Medical Corporation, Communicable Diseases Centre, Doha, Qatar
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2
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Lahiri S, Banerjee A, Bhutda S, Palaniappan M, Bahubali VH, Manjunath N, Maji S, Siddaiah N. In vitro expression of vital virulent genes of clinical and environmental isolates of Cryptococcus neoformans/gattii in endothelial cells of human blood-brain barrier. J Mycol Med 2019; 29:239-244. [PMID: 31221506 DOI: 10.1016/j.mycmed.2019.06.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 06/02/2019] [Accepted: 06/04/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Evaluation of the pathogenesis of clinical and environmental cryptococcal isolates to the central nervous system is necessary for understanding the risk. This study was designed to determine the in vitro expression of six important virulent genes of Cryptococcus neoformans/gattii in Human Brain Microvascular Endothelial cells (hBMEC). METHODS The hBMEC were infected with Cryptococcus to determine invasion and survival rate at 3, 12 and 24hours by subsequent colony count of internalized yeasts. The whole RNA of the intracellular Cryptococcus was extracted to quantify the expression of CAP10, PLB1, ENA1, URE1, LAC1, and MATα genes by real-time quantitative PCR for 3 and 12hours of infection. RESULTS Invasion and survival rates were higher in clinical and standard strains of C. neoformans. A significant difference was observed among the clinical and environmental isolates for the expression of CAP10, ENA1, LAC1, MATα and URE1 at 3hours, and ENA1, LAC1, MATα, PLB1 and URE1 at 12hours. Clinical isolates showed significant upregulation of all the genes except PLB1, which was higher in environmental isolates. Relative expressions at the two time-points showed statistically significant (P=0.043) changes for the clinical isolates and no significance (P=0.063) for environmental isolates. CONCLUSION The C. gattii (VGI) isolates showed significantly lower invasion and survival than C. neoformans (VNI, and VNII) irrespective of their sources. Clinical isolates exhibited higher expression for the majority of the virulent genes until 12hours of infection, probably due to their better adaptation in the host system and enhanced pathogenicity than the environmental counterparts.
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Affiliation(s)
- S Lahiri
- Department of Neuromicrobiology, National Institute of Mental Health & Neuro Sciences (NIMHANS), Bangalore, India
| | - A Banerjee
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Mumbai, India
| | - S Bhutda
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Mumbai, India
| | - M Palaniappan
- Department of Biostatistics, NIMHANS, Bangalore, India
| | - V H Bahubali
- Department of Neuromicrobiology, National Institute of Mental Health & Neuro Sciences (NIMHANS), Bangalore, India
| | - N Manjunath
- Department of Neurology, NIMHANS, Bangalore, India
| | - S Maji
- Department of Neuromicrobiology, National Institute of Mental Health & Neuro Sciences (NIMHANS), Bangalore, India
| | - N Siddaiah
- Department of Neuromicrobiology, National Institute of Mental Health & Neuro Sciences (NIMHANS), Bangalore, India.
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Cui W, Li X, Hull L, Xiao M. GATA-type transcription factors play a vital role in radiation sensitivity of Cryptococcus neoformans by regulating the gene expression of specific amino acid permeases. Sci Rep 2019; 9:6385. [PMID: 31015536 PMCID: PMC6478845 DOI: 10.1038/s41598-019-42778-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 03/26/2019] [Indexed: 11/16/2022] Open
Abstract
Cryptococcus neoformans is a basidiomycete fungus that is highly resistant to ionizing radiation and has been identified in highly radioactive environments. Transcription factors (TFs) are master regulators of gene expression by binding to specific DNA sequences within promoters of target genes. A library of 322 signature-tagged gene deletion strains for 155 C. neoformans TF genes has been established. Previous phenome-based functional analysis of the C. neoformans TF mutant library identified key TFs important for various phenotypes, such as growth, differentiation, virulence-factor production, and stress responses. Here, utilizing the established TF mutant library, we identified 5 TFs that are important for radiation sensitivity, including SRE1, BZP2, GAT5, GAT6, and HCM1. Interestingly, BZP2, GAT5 and GAT6 all belong to the GATA-type transcription factors. These factors regulate transcription of nitrogen catabolite repression (NCR) sensitive genes when preferred nitrogen sources are absent or limiting. In addition to radiation, we found that specific GATA factors are important for other stressors such as rapamycin, fluconazole, and hydroxyurea treatment. Using real-time PCR method, we studied the expression of GATA down-stream genes after radiation exposure and identified that AAP4, AAP5 and URO1 were differentially expressed in the GAT5 and GAT6 mutants compared to the wild type cells. In summary, our data suggest that GATA TFs are important for radiation sensitivity in C. neoformans by regulating specific downstream AAP genes.
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Affiliation(s)
- Wanchang Cui
- Radiation Countermeasures Program, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - XiangHong Li
- Radiation Countermeasures Program, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Lisa Hull
- Radiation Countermeasures Program, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Mang Xiao
- Radiation Countermeasures Program, Armed Forces Radiobiology Research Institute, Uniformed Services University of the Health Sciences, Bethesda, MD, USA.
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Atypical Radiographic Presentation of Cryptococcus Pneumonia in a Newly Diagnosed HIV Patient. Case Rep Infect Dis 2019; 2019:9032958. [PMID: 31032130 PMCID: PMC6458939 DOI: 10.1155/2019/9032958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/13/2019] [Indexed: 12/28/2022] Open
Abstract
Background Cryptococcus infection is an opportunistic infection that occurs primarily among immunocompromised patients, and the morbidity and mortality of this infection is high if left unrecognized and untreated. There are no clinical or radiographic characteristics typical of cryptococcal pneumonia, and its clinical and radiological presentations often overlap with other diagnoses. Case Presentation We present a case of a 25-year-old man from Ghana admitted for an altered mental state, weight loss, neck pain, fever, and photophobia. He was diagnosed with Cryptococcus neoformans meningitis by cerebrospinal fluid culture and with disseminated cryptococcal infection by a positive Cryptococcus blood test. Diffuse micronodular opacities were found in a miliary pattern in the upper portions of both lungs upon imaging, which suggested miliary tuberculosis; thus, the patient was started on antituberculosis therapy. The patient underwent flexible fiber optic bronchoscopy, and transbronchial biopsy of the right lung showed bronchopneumonia with fungal spores consistent with filamentous Cryptococcus neoformans, which grew in tissue culture of the right lung. Interferon-gamma release assay, Mycobacterium tuberculosis PCR, and acid-fast bacilli staining of the bronchoalveolar lavage were negative for the M. tuberculosis complex. Conclusion The similarities in clinical and imaging findings among patients with acute immunodeficiency syndrome with coinfections make diagnoses difficult; thus image-guided biopsies are essential to confirm diagnoses.
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Lahiri Mukhopadhyay S, Bahubali VH, Manjunath N, Swaminathan A, Maji S, Palaniappan M, Parthasarathy S, Chandrashekar N. Central nervous system infection due to Cryptococcus gattii sensu lato
in India: Analysis of clinical features, molecular profile and antifungal susceptibility. Mycoses 2017; 60:749-757. [DOI: 10.1111/myc.12656] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2016] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 12/16/2022]
Affiliation(s)
| | - Veenakumari H. Bahubali
- Department of Neuromicrobiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - Netravathi Manjunath
- Department of Neurology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - Aarthi Swaminathan
- Department of Neuroimaging and Interventional Radiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - Sayani Maji
- Department of Neuromicrobiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | - Marimuthu Palaniappan
- Department of Biostatistics; National Institute of Mental Health and Neuro Sciences; Bangalore India
| | | | - Nagarathna Chandrashekar
- Department of Neuromicrobiology; National Institute of Mental Health and Neuro Sciences; Bangalore India
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Cryptococcus: Shedding New Light on an Inveterate Yeast. J Fungi (Basel) 2015; 1:115-129. [PMID: 29376903 PMCID: PMC5753104 DOI: 10.3390/jof1020115] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 07/01/2015] [Accepted: 07/08/2015] [Indexed: 12/26/2022] Open
Abstract
Cryptococcus has emerged as a significant pathogen in immunocompromised patients. While the diagnostic testing and the antifungal treatment of cryptococcal infections have become firmly established in clinical practice, new developments and areas of ambiguity merit further consideration. These include the potential for donor transmission of Cryptococcus; cirrhosis-associated cryptococcosis, particularly during transplant candidacy; the utility of serum cryptococcal antigen testing of asymptomatic individuals in high-prevalence, poor-resource areas; pathogenesis and treatment of the immune reconstitution syndrome, specifically in relation to antiretroviral therapy and immunosuppressive medications; and new challenges posed by the emerging species of Cryptococcus gatti. In this article, we summarize the literature pertaining to these topics, focusing on recent progress.
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Abstract
Understanding of the taxonomy and phylogeny of Cryptococcus gattii has been advanced by modern molecular techniques. C. gattii probably diverged from Cryptococcus neoformans between 16 million and 160 million years ago, depending on the dating methods applied, and maintains diversity by recombining in nature. South America is the likely source of the virulent C. gattii VGII molecular types that have emerged in North America. C. gattii shares major virulence determinants with C. neoformans, although genomic and transcriptomic studies revealed that despite similar genomes, the VGIIa and VGIIb subtypes employ very different transcriptional circuits and manifest differences in virulence phenotypes. Preliminary evidence suggests that C. gattii VGII causes severe lung disease and death without dissemination, whereas C. neoformans disseminates readily to the central nervous system (CNS) and causes death from meningoencephalitis. Overall, currently available data indicate that the C. gattii VGI, VGII, and VGIII molecular types more commonly affect nonimmunocompromised hosts, in contrast to VGIV. New, rapid, cheap diagnostic tests and imaging modalities are assisting early diagnosis and enabling better outcomes of cerebral cryptococcosis. Complications of CNS infection include increased intracranial pressure, severe neurological sequelae, and development of immune reconstitution syndrome, although the mortality rate is low. C. gattii VGII isolates may exhibit higher fluconazole MICs than other genotypes. Optimal therapeutic regimens are yet to be determined; in most cases, initial therapy with amphotericin B and 5-flucytosine is recommended.
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Hull CM, Purdy NJ, Moody SC. Mitigation of human-pathogenic fungi that exhibit resistance to medical agents: can clinical antifungal stewardship help? Future Microbiol 2015; 9:307-25. [PMID: 24762306 DOI: 10.2217/fmb.13.160] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Reducing indiscriminate antimicrobial usage to combat the expansion of multidrug-resistant human-pathogenic bacteria is fundamental to clinical antibiotic stewardship. In contrast to bacteria, fungal resistance traits are not understood to be propagated via mobile genetic elements, and it has been proposed that a global explosion of resistance to medical antifungals is therefore unlikely. Clinical antifungal stewardship has focused instead on reducing the drug toxicity and high costs associated with medical agents. Mitigating the problem of human-pathogenic fungi that exhibit resistance to antimicrobials is an emergent issue. This article addresses the extent to which clinical antifungal stewardship could influence the scale and epidemiology of resistance to medical antifungals both now and in the future. The importance of uncharted selection pressure exerted by agents outside the clinical setting (agricultural pesticides, industrial xenobiotics, biocides, pharmaceutical waste and others) on environmentally ubiquitous spore-forming molds that are lesserstudied but increasingly responsible for drug-refractory infections is considered.
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Affiliation(s)
- Claire M Hull
- Swansea University, College of Medicine, Institute of Life Science: Microbes & Immunity, SA2 8PP, Wales, UK
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9
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Liu BX, Dai XJ, Liu H, Gong HH, Wang YXJ, Zhang LL. Cerebellar cryptococcosis characterized by a space-occupying lesion in an immunocompetent non-HIV patient. Neuropsychiatr Dis Treat 2015; 11:21-4. [PMID: 25552907 PMCID: PMC4277240 DOI: 10.2147/ndt.s75432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Central nervous system (CNS) cryptococcosis is an opportunistic fungal infection that typically occurs in patients with reduced immunological function, such as patients with AIDS, patients receiving organ transplants, or patients receiving corticosteroid and immunosuppressive therapy. CNS cryptococcosis rarely occurs in immunocompetent patients. CNS cryptococcosis is characterized by meningitis and encephalitis and occasionally forms isolated granulomas. Isolated cerebellar cryptococcoma is a rare condition, especially in immunocompetent patients, and the misdiagnosis rate is high. A definite diagnosis must be based on pathology. To raise awareness of this disease, the clinical data of a patient with cryptococcomas in the right side of the cerebellum are reported.
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Affiliation(s)
- Bi-Xia Liu
- Department of Infectious Diseases, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Xi-Jian Dai
- Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong ; Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Heng Liu
- Department of Radiology, Affiliated Hospital of Zunyi Medical University, Guizhou, People's Republic of China
| | - Hong-Han Gong
- Department of Radiology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People's Republic of China
| | - Yi-Xiang J Wang
- Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Lun-Li Zhang
- Department of Infectious Diseases, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, People's Republic of China
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Richardson TE, Lee NE, Cykowski MD, Chang SA, Powell SZ. Necrotizing fasciitis as the initial presentation of disseminated infection with fluconazole-resistant Cryptococcus neoformans. JMM Case Rep 2014; 1:e003608. [PMID: 28663814 PMCID: PMC5415936 DOI: 10.1099/jmmcr.0.003608-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 11/12/2014] [Indexed: 01/21/2023] Open
Abstract
Introduction: Cryptococcus neoformans is an encapsulated budding yeast that is a common cause of opportunistic infections, rarely giving rise to cellulitis, vasculitis or fasciitis. Necrotizing fasciitis caused by C. neoformans is a rare but serious problem in post-transplant immunosuppression. Case presentation: We report a case of cryptococcal necrotizing fasciitis in the left adductor longus of a patient on immunosuppressive therapy. The patient’s medical history was significant for orthotopic heart transplant secondary to cardiac and systemic amyloidosis (AL type) with subsequent cardiac biopsy demonstrating mild rejection (grade 1R). A thigh muscle biopsy demonstrated numerous encapsulated fungi in the fascia and no evidence of myositis. Cryptococcal antigen was subsequently identified in the patient’s serum and cerebrospinal fluid. The patient progressed to involvement of the central nervous system, left biceps femoris and skin of the left lower leg by fluconazole-resistant C. neoformans. Conclusion: This case illustrates a rare initial presentation of disseminated fluconazole-resistant C. neoformans as an isolated necrotizing fasciitis of the thigh. Necrotizing fungal fasciitis should be considered in immunosuppressed patients with clinical findings of either myositis or cellulitis of a lower extremity.
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Affiliation(s)
- Timothy E Richardson
- Texas College of Osteopathic Medicine and The Department of Pharmacology & Neuroscience, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Nathan E Lee
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Weill Cornell Medical College, Houston, TX 77030, USA
| | - Matthew D Cykowski
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Weill Cornell Medical College, Houston, TX 77030, USA
| | - Spencer A Chang
- Department of Radiology, Houston Methodist Hospital, Weill Cornell Medical College, Houston, TX 77030, USA
| | - Suzanne Z Powell
- Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Weill Cornell Medical College, Houston, TX 77030, USA
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Franco-Paredes C, Womack T, Bohlmeyer T, Sellers B, Hays A, Patel K, Lizarazo J, Lockhart SR, Siddiqui W, Marr KA. Management of Cryptococcus gattii meningoencephalitis. THE LANCET. INFECTIOUS DISEASES 2014; 15:348-55. [PMID: 25467646 DOI: 10.1016/s1473-3099(14)70945-4] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Cryptococcosis is a fungal disease caused by Cryptococcus neoformans and Cryptococcus gattii. By inhalation and subsequent pulmonary infection, it may disseminate to the CNS and cause meningitis or meningoencephalitis. Most cases occur in immunosuppressed hosts, including patients with HIV/AIDS, patients receiving immunosuppressing drugs, and solid organ transplant recipients. However, cryptococcosis also occurs in individuals with apparently healthy immune systems. A growing number of cases are caused by C gattii, with infections occurring in both immunosuppressed and immunocompetent individuals. In the majority of documented cases, treatment of C gattii infection of the CNS requires aggressive management of raised intracranial pressure along with standard antifungal therapy. Early cerebrospinal fluid evacuation is often needed through placement of a percutaneous lumbar drain or ventriculostomy. Furthermore, pharmacological immunosuppression with a high dose of dexamethasone is sometimes needed to ameliorate a persistently increased inflammatory response and to reduce intracranial pressure. In this Grand Round, we present the case of an otherwise healthy adolescent female patient, who, despite aggressive management, succumbed to C gattii meningoencephalitis. We also present a review of the existing literature and discuss optimum clinical management of meningoencephalitis caused by C gattii.
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Affiliation(s)
- Carlos Franco-Paredes
- Phoebe Putney Memorial Hospital, Albany, GA, USA; Hospital Infantil de Mexico, Federico Gomez, Mexico City, Mexico.
| | - Tanea Womack
- Phoebe Putney Memorial Hospital, Albany, GA, USA
| | | | | | - Allison Hays
- Phoebe Putney Memorial Hospital, Albany, GA, USA
| | | | - Jairo Lizarazo
- Hospital Universitario Erasmo Meoz, Cúcuta, Norte de Santander, Colombia
| | | | | | - Kieren A Marr
- Johns Hopkins University Medical Center, Baltimore, MD, USA; the Sidney Kimmel Comprehensive Cancer Center, Baltimore, MD, USA
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Coelho C, Bocca AL, Casadevall A. The tools for virulence of Cryptococcus neoformans. ADVANCES IN APPLIED MICROBIOLOGY 2014; 87:1-41. [PMID: 24581388 DOI: 10.1016/b978-0-12-800261-2.00001-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cryptococcus neoformans is a fungal pathogen that causes almost half a million deaths each year. It is believed that most humans are infected with C. neoformans, possibly in a form that survives through latency in the lung and can reactivate to cause disease if the host becomes immunosuppressed. C. neoformans has a remarkably sophisticated intracellular survival capacities yet it is a free-living fungus with no requirement for mammalian virulence whatsoever. In this review, we discuss the tools that C. neoformans possesses to achieve survival, latency and virulence within its host. Some of these tools are mechanisms to withstand starvation and others aim to protect against microbicidal molecules produced by the immune system. Furthermore, we discuss how these tools were acquired through evolutionary pressures and perhaps accidental stochastic events, all of which combined to produce an organism with an unusual and unique intracellular pathogenic strategy.
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Affiliation(s)
- Carolina Coelho
- Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, New York, USA; Centre for Neuroscience and Cell Biology of Coimbra, Institute of Microbiology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Anamelia Lorenzetti Bocca
- Department of Cellular Biology, Institute of Biological Sciences, University of Brasília, Brasília, Brazil
| | - Arturo Casadevall
- Department of Microbiology and Immunology, Albert Einstein College of Medicine of Yeshiva University, New York, USA.
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Estrogen receptor antagonists are anti-cryptococcal agents that directly bind EF hand proteins and synergize with fluconazole in vivo. mBio 2014; 5:e00765-13. [PMID: 24520056 PMCID: PMC3950514 DOI: 10.1128/mbio.00765-13] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptococcosis is an infectious disease of global significance for which new therapies are needed. Repurposing previously developed drugs for new indications can expedite the translation of new therapies from bench to beside. Here, we characterized the anti-cryptococcal activity and antifungal mechanism of estrogen receptor antagonists related to the breast cancer drugs tamoxifen and toremifene. Tamoxifen and toremifene are fungicidal and synergize with fluconazole and amphotericin B in vitro. In a mouse model of disseminated cryptococcosis, tamoxifen at concentrations achievable in humans combines with fluconazole to decrease brain burden by ~1 log10. In addition, these drugs inhibit the growth of Cryptococcus neoformans within macrophages, a niche not accessible by current antifungal drugs. Toremifene and tamoxifen directly bind to the essential EF hand protein calmodulin, as determined by thermal shift assays with purified C. neoformans calmodulin (Cam1), prevent Cam1 from binding to its well-characterized substrate calcineurin (Cna1), and block Cna1 activation. In whole cells, toremifene and tamoxifen block the calcineurin-dependent nuclear localization of the transcription factor Crz1. A large-scale chemical genetic screen with a library of C. neoformans deletion mutants identified a second EF hand-containing protein, which we have named calmodulin-like protein 1 (CNAG_05655), as a potential target, and further analysis showed that toremifene directly binds Cml1 and modulates its ability to bind and activate Cna1. Importantly, tamoxifen analogs (idoxifene and methylene-idoxifene) with increased calmodulin antagonism display improved anti-cryptococcal activity, indicating that calmodulin inhibition can be used to guide a systematic optimization of the anti-cryptococcal activity of the triphenylethylene scaffold. Worldwide, cryptococcosis affects approximately 1 million people annually and kills more HIV/AIDS patients per year than tuberculosis. The gold standard therapy for cryptococcosis is amphotericin B plus 5-flucytosine, but this regimen is not readily available in regions where resources are limited and where the burden of disease is highest. Herein, we show that molecules related to the breast cancer drug tamoxifen are fungicidal for Cryptococcus and display a number of pharmacological properties desirable for an anti-cryptococcal drug, including synergistic fungicidal activity with fluconazole in vitro and in vivo, oral bioavailability, and activity within macrophages. We have also demonstrated that this class of molecules targets calmodulin as part of their mechanism of action and that tamoxifen analogs with increased calmodulin antagonism have improved anti-cryptococcal activity. Taken together, these results indicate that tamoxifen is a pharmacologically attractive scaffold for the development of new anti-cryptococcal drugs and provide a mechanistic basis for its further optimization.
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Harris JR, Galanis E, Lockhart SR. Cryptococcus gattii Infections and Virulence. CURRENT FUNGAL INFECTION REPORTS 2014. [DOI: 10.1007/s12281-013-0170-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Affiliation(s)
- David M. Morens
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
| | - Anthony S. Fauci
- National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
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Calcineurin governs thermotolerance and virulence of Cryptococcus gattii. G3-GENES GENOMES GENETICS 2013; 3:527-39. [PMID: 23450261 PMCID: PMC3583459 DOI: 10.1534/g3.112.004242] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 01/12/2013] [Indexed: 12/26/2022]
Abstract
The pathogenic yeast Cryptococcus gattii, which is causing an outbreak in the Pacific Northwest region of North America, causes life-threatening pulmonary infections and meningoencephalitis in healthy individuals, unlike Cryptococcus neoformans, which commonly infects immunocompromised patients. In addition to a greater predilection for C. gattii to infect healthy hosts, the C. gattii genome sequence project revealed extensive chromosomal rearrangements compared with C. neoformans, showing genomic differences between the two Cryptococcus species. We investigated the roles of C. gattii calcineurin in three molecular types: VGIIa (R265), VGIIb (R272), and VGI (WM276). We found that calcineurin exhibits a differential requirement for growth on solid medium at 37°, as calcineurin mutants generated from R265 were more thermotolerant than mutants from R272 and WM276. We demonstrated that tolerance to calcineurin inhibitors (FK506, CsA) at 37° is linked with the VGIIa molecular type. The calcineurin mutants from the R272 background showed the most extensive growth and morphological defects (multivesicle and larger ring-like cells), as well as increased fluconazole susceptibility. Our cellular architecture examination showed that C. gattii and C. neoformans calcineurin mutants exhibit plasma membrane disruptions. Calcineurin in the C. gattii VGII molecular type plays a greater role in controlling cation homeostasis compared with that in C. gattii VGI and C. neoformans H99. Importantly, we demonstrate that C. gattii calcineurin is essential for virulence in a murine inhalation model, supporting C. gattii calcineurin as an attractive antifungal drug target.
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New Insights into HIV/AIDS-Associated Cryptococcosis. ISRN AIDS 2013; 2013:471363. [PMID: 24052889 PMCID: PMC3767198 DOI: 10.1155/2013/471363] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 01/10/2013] [Indexed: 12/27/2022]
Abstract
Cryptococcal meningitis is a life-threatening opportunistic fungal infection in both HIV-infected and HIV-uninfected patients. According to the most recent taxonomy, the responsible fungus is classified into a complex that contains two species (Cryptococcus neoformans and C. gattii), with eight major molecular types. HIV infection is recognized worldwide as the main underlying disease responsible for the development of cryptococcal meningitis (accounting for 80-90% of cases). In several areas of sub-Saharan Africa with the highest HIV prevalence despite the recent expansion of antiretroviral (ARV) therapy programme, cryptococcal meningitis is the leading cause of community-acquired meningitis with a high mortality burden. Although cryptococcal meningitis should be considered a neglected disease, a large body of knowledge has been developed by several studies performed in recent years. This paper will focus especially on new clinical aspects such as immune reconstitution inflammatory syndrome, advances on management, and strategies for the prevention of clinical disease.
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Butts A, DiDone L, Koselny K, Baxter BK, Chabrier-Rosello Y, Wellington M, Krysan DJ. A repurposing approach identifies off-patent drugs with fungicidal cryptococcal activity, a common structural chemotype, and pharmacological properties relevant to the treatment of cryptococcosis. EUKARYOTIC CELL 2013; 12:278-87. [PMID: 23243064 PMCID: PMC3571299 DOI: 10.1128/ec.00314-12] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2012] [Accepted: 12/10/2012] [Indexed: 11/20/2022]
Abstract
New, more accessible therapies for cryptococcosis represent an unmet clinical need of global importance. We took a repurposing approach to identify previously developed drugs with fungicidal activity toward Cryptococcus neoformans, using a high-throughput screening assay designed to detect drugs that directly kill fungi. From a set of 1,120 off-patent medications and bioactive molecules, we identified 31 drugs/molecules with fungicidal activity, including 15 drugs for which direct antifungal activity had not previously been reported. A significant portion of the drugs are orally bioavailable and cross the blood-brain barrier, features key to the development of a widely applicable anticryptococcal agent. Structural analysis of this set revealed a common chemotype consisting of a hydrophobic moiety linked to a basic amine, features that are common to drugs that cross the blood-brain barrier and access the phagolysosome, two important niches of C. neoformans. Consistent with their fungicidal activity, the set contains eight drugs that are either additive or synergistic in combination with fluconazole. Importantly, we identified two drugs, amiodarone and thioridazine, with activity against intraphagocytic C. neoformans. Finally, the set of drugs is also enriched for molecules that inhibit calmodulin, and we have confirmed that seven drugs directly bind C. neoformans calmodulin, providing a molecular target that may contribute to the mechanism of antifungal activity. Taken together, these studies provide a foundation for the optimization of the antifungal properties of a set of pharmacologically attractive scaffolds for the development of novel anticryptococcal therapies.
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Affiliation(s)
| | | | | | | | | | | | - Damian J. Krysan
- Pediatrics
- Microbiology/Immunology, University of Rochester, Rochester, New York, USA
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