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Nayak A, Khedri A, Chavarria A, Sanders KN, Ghalei H, Khoshnevis S. Sinefungin, a natural nucleoside analog of S-adenosyl methionine, impairs the pathogenicity of Candida albicans. NPJ ANTIMICROBIALS AND RESISTANCE 2024; 2:23. [PMID: 39268078 PMCID: PMC11391927 DOI: 10.1038/s44259-024-00040-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 07/19/2024] [Indexed: 09/15/2024]
Abstract
Candida albicans, an opportunistic fungal pathogen, causes life-threatening infections in immunocompromised patients. Current antifungals are limited by toxicity, drug-drug interactions, and emerging resistance, underscoring the importance of identifying novel treatment approaches. Here, we elucidate the impact of sinefungin, an analog of S-adenosyl methionine, on the virulence of C. albicans strain SC5314 and clinical isolates. Our data indicate that sinefungin impairs pathogenic traits of C. albicans including hyphal morphogenesis, biofilm formation, adhesion to epithelial cells, and virulence towards Galleria mellonella, highlighting sinefungin as an avenue for therapeutic intervention. We determine that sinefungin particularly disturbs N6-methyladenosine (m6A) formation. Transcriptome analysis of C. albicans hyphae upon sinefungin treatment reveals an increase in transcripts related to the yeast form and decrease in those associated with hyphae formation and virulence. Collectively, our data propose sinefungin as a potent molecule against C. albicans and emphasize further exploration of post-transcriptional control mechanisms of pathogenicity for antifungal design.
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Affiliation(s)
- Anushka Nayak
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Azam Khedri
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Alejandro Chavarria
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Kyla N. Sanders
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Homa Ghalei
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Sohail Khoshnevis
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
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2
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Xiong J, Wang L, Feng Y, Zhen C, Hang S, Yu J, Lu H, Jiang Y. Geldanamycin confers fungicidal properties to azole by triggering the activation of succinate dehydrogenase. Life Sci 2024; 348:122699. [PMID: 38718854 DOI: 10.1016/j.lfs.2024.122699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/17/2024] [Accepted: 05/04/2024] [Indexed: 05/13/2024]
Abstract
AIMS Azoles have been widely employed for the treatment of invasive fungal diseases; however, their efficacy is diminished as pathogenic fungi tolerate them due to their fungistatic properties. Geldanamycin (GdA) can render azoles fungicidal by inhibiting the ATPase and molecular chaperone activities of heat shock protein 90 (Hsp90). Nonetheless, the clinical applicability of GdA is restricted due to its cytotoxic ansamycin scaffold structure, its induction of cytoprotective heat shock responses, and the conservative nature of Hsp90. Hence, it is imperative to elucidate the mechanism of action of GdA to confer fungicidal properties to azoles and mitigate the toxic adverse effects associated with GdA. MATERIALS AND METHODS Through various experimental methods, including the construction of gene-deleted Candida albicans mutants, in vitro drug sensitivity experiments, Western blot analysis, reactive oxygen species (ROS) assays, and succinate dehydrogenase activity assays, we identified Hsp90 client proteins associated with the tolerance of C. albicans to azoles. KEY FINDINGS It was observed that GdA effectively hindered the entry of Hsp90 into mitochondria, resulting in the alleviation of inhibitory effect of Hsp90 on succinate dehydrogenase. Consequently, the activation of succinate dehydrogenase led to an increased production of ROS. within the mitochondria, thereby facilitating the antifungal effects of azoles against C. albicans. SIGNIFICANCE This research presents a novel approach for conferring fungicidal properties to azoles, which involves specifically disrupting the interaction of between Hsp90 and succinate dehydrogenase rather than employing a non-specific inhibition of ATPase activity of Hsp90.
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Affiliation(s)
- Juan Xiong
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Li Wang
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Yanru Feng
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Cheng Zhen
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Sijin Hang
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Jinhua Yu
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China
| | - Hui Lu
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China.
| | - Yuanying Jiang
- Department of Pharmacy, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai 200092, China.
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3
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Day AW, Kumamoto CA. Selection of ethanol tolerant strains of Candida albicans by repeated ethanol exposure results in strains with reduced susceptibility to fluconazole. PLoS One 2024; 19:e0298724. [PMID: 38377103 PMCID: PMC10878505 DOI: 10.1371/journal.pone.0298724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Accepted: 01/23/2024] [Indexed: 02/22/2024] Open
Abstract
Candida albicans is a commensal yeast that has important impacts on host metabolism and immune function, and can establish life-threatening infections in immunocompromised individuals. Previously, C. albicans colonization has been shown to contribute to the progression and severity of alcoholic liver disease. However, relatively little is known about how C. albicans responds to changing environmental conditions in the GI tract of individuals with alcohol use disorder, namely repeated exposure to ethanol. In this study, we repeatedly exposed C. albicans to high concentrations (10% vol/vol) of ethanol-a concentration that can be observed in the upper GI tract of humans following consumption of alcohol. Following this repeated exposure protocol, ethanol small colony (Esc) variants of C. albicans isolated from these populations exhibited increased ethanol tolerance, altered transcriptional responses to ethanol, and cross-resistance/tolerance to the frontline antifungal fluconazole. These Esc strains exhibited chromosomal copy number variations and carried polymorphisms in genes previously associated with the acquisition of fluconazole resistance during human infection. This study identifies a selective pressure that can result in evolution of fluconazole tolerance and resistance without previous exposure to the drug.
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Affiliation(s)
- Andrew W. Day
- Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, United States of America
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
| | - Carol A. Kumamoto
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, United States of America
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4
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Choi Y, Yu SR, Lee Y, Na AY, Lee S, Heitman J, Seo R, Lee HS, Lee JS, Bahn YS. Casein kinase 2 complex: a central regulator of multiple pathobiological signaling pathways in Cryptococcus neoformans. mBio 2024; 15:e0327523. [PMID: 38193728 PMCID: PMC10865844 DOI: 10.1128/mbio.03275-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 01/10/2024] Open
Abstract
The casein kinase 2 (CK2) complex has garnered extensive attention over the past decades as a potential therapeutic target for diverse human diseases, including cancer, diabetes, and obesity, due to its pivotal roles in eukaryotic growth, differentiation, and metabolic homeostasis. While CK2 is also considered a promising antifungal target, its role in fungal pathogens remains unexplored. In this study, we investigated the functions and regulatory mechanisms of the CK2 complex in Cryptococcus neoformans, a major cause of fungal meningitis. The cryptococcal CK2 complex consists of a single catalytic subunit, Cka1, and two regulatory subunits, Ckb1 and Ckb2. Our findings show that Cka1 plays a primary role as a protein kinase, while Ckb1 and Ckb2 have major and minor regulatory functions, respectively, in growth, cell cycle control, morphogenesis, stress response, antifungal drug resistance, and virulence factor production. Interestingly, triple mutants lacking all three subunits (cka1Δ ckb1Δ ckb2Δ) exhibited more severe phenotypic defects than the cka1Δ mutant alone, suggesting that Ckb1/2 may have Cka1-independent functions. In a murine model of systemic cryptococcosis, cka1Δ and cka1Δ ckb1Δ ckb2Δ mutants showed severely reduced virulence. Transcriptomic, proteomic, and phosphoproteomic analyses further revealed that the CK2 complex controls a wide array of effector proteins involved in transcriptional regulation, cell cycle control, nutrient metabolisms, and stress responses. Most notably, CK2 disruption led to dysregulation of key signaling cascades central to C. neoformans pathogenicity, including the Hog1, Mpk1 MAPKs, cAMP/PKA, and calcium/calcineurin signaling pathways. In summary, our study provides novel insights into the multifaceted roles of the fungal CK2 complex and presents a compelling case for targeting it in the development of new antifungal drugs.IMPORTANCEThe casein kinase 2 (CK2) complex, crucial for eukaryotic growth, differentiation, and metabolic regulation, presents a promising therapeutic target for various human diseases, including cancer, diabetes, and obesity. Its potential as an antifungal target is further highlighted in this study, which explores CK2's functions in C. neoformans, a key fungal meningitis pathogen. The CK2 complex in C. neoformans, comprising the Cka1 catalytic subunit and Ckb1/2 regulatory subunits, is integral to processes like growth, cell cycle, morphogenesis, stress response, drug resistance, and virulence. Our findings of CK2's role in regulating critical signaling pathways, including Hog1, Mpk1 MAPKs, cAMP/PKA, and calcium/calcineurin, underscore its importance in C. neoformans pathogenicity. This study provides valuable insights into the fungal CK2 complex, reinforcing its potential as a target for novel antifungal drug development and pointing out a promising direction for creating new antifungal agents.
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Affiliation(s)
- Yeseul Choi
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Seong-Ryong Yu
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Yujin Lee
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
| | - Ann-Yae Na
- School of Pharmacy, Sungkyunkwan University, Suwon, South Korea
| | - Sangkyu Lee
- School of Pharmacy, Sungkyunkwan University, Suwon, South Korea
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Ran Seo
- AmtixBio Co., Ltd., Hanam-si, Gyeonggi-do, South Korea
| | - Han-Seung Lee
- AmtixBio Co., Ltd., Hanam-si, Gyeonggi-do, South Korea
| | | | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, South Korea
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5
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Day AW, Kumamoto CA. Selection of Ethanol Tolerant Strains of Candida albicans by Repeated Ethanol Exposure Results in Strains with Reduced Susceptibility to Fluconazole. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.13.557677. [PMID: 37745460 PMCID: PMC10515905 DOI: 10.1101/2023.09.13.557677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Candida albicans is a commensal yeast that has important impacts on host metabolism and immune function, and can establish life-threatening infections in immunocompromised individuals. Previously, C. albicans colonization has been shown to contribute to the progression and severity of alcoholic liver disease. However, relatively little is known about how C. albicans responds to changing environmental conditions in the GI tract of individuals with alcohol use disorder, namely repeated exposure to ethanol. In this study, we repeatedly exposed C. albicans to high concentrations (10% vol/vol) of ethanol-a concentration that can be observed in the upper GI tract of humans following consumption of alcohol. Following this repeated exposure protocol, ethanol small colony (Esc) variants of C. albicans isolated from these populations exhibited increased ethanol tolerance, altered transcriptional responses to ethanol, and cross-resistance/tolerance to the frontline antifungal fluconazole. These Esc strains exhibited chromosomal copy number variations and carried polymorphisms in genes previously associated with the acquisition of fluconazole resistance during human infection. This study identifies a selective pressure that can result in evolution of fluconazole tolerance and resistance without previous exposure to the drug.
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Affiliation(s)
- Andrew W. Day
- Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts, 02111, USA
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, 02111, USA
| | - Carol A. Kumamoto
- Department of Molecular Biology and Microbiology, Tufts University, Boston, Massachusetts, 02111, USA
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6
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Jakobson CM, Aguilar-Rodríguez J, Jarosz DF. Hsp90 shapes adaptation by controlling the fitness consequences of regulatory variation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.30.564848. [PMID: 37961536 PMCID: PMC10634948 DOI: 10.1101/2023.10.30.564848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The essential stress-responsive chaperone Hsp90 impacts development and adaptation from microbes to humans. Yet despite evidence of its role in evolution, pathogenesis, and oncogenic transformation, the molecular mechanisms by which Hsp90 alters the consequences of mutations remain vigorously debated. Here we exploit the power of nucleotide-resolution genetic mapping in Saccharomyces cerevisiae to uncover more than 1,000 natural variant-to-phenotype associations governed by this molecular chaperone. Strikingly, Hsp90 more frequently modified the phenotypic effects of cis-regulatory variation than variants that altered protein sequence. Moreover, these interactions made the largest contribution to Hsp90-dependent heredity. Nearly all interacting variants-both regulatory and protein-coding-fell within clients of Hsp90 or targets of its direct binding partners. Hsp90 activity affected mutations in evolutionarily young genes, segmental deletions, and heterozygotes, highlighting its influence on variation central to evolutionary novelty. Reconciling the diverse epistatic effects of this chaperone, synthetic transcriptional regulation and reconstructions of natural alleles by genome editing revealed a central role for Hsp90 in regulating the fundamental relationship between activity and phenotype. Our findings establish that non-coding variation is a core driver of Hsp90's influence on heredity, offering a mechanistic explanation for the chaperone's strong effects on evolution and development across species.
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Affiliation(s)
- Christopher M. Jakobson
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
- These authors contributed equally
| | - José Aguilar-Rodríguez
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Biology, Stanford University, Stanford, CA, USA
- These authors contributed equally
| | - Daniel F. Jarosz
- Department of Chemical and Systems Biology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA
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7
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Robbins N, Cowen LE. Roles of Hsp90 in Candida albicans morphogenesis and virulence. Curr Opin Microbiol 2023; 75:102351. [PMID: 37399670 PMCID: PMC11016340 DOI: 10.1016/j.mib.2023.102351] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 06/02/2023] [Accepted: 06/04/2023] [Indexed: 07/05/2023]
Abstract
Hsp90 is a conserved molecular chaperone that facilitates the folding and function of hundreds of client proteins, many of which serve as core hubs of signal transduction networks. Hsp90 has a critical role in virulence of the opportunistic fungal pathogen Candida albicans, which exists as a natural commensal of the human microbiota and is a leading cause of invasive fungal infections, particularly in immunocompromised individuals. The ability of C. albicans to cause disease is tightly coupled to its capacity to undergo a morphogenetic transition between yeast and filamentous forms. Here, we describe the complex mechanisms by which Hsp90 regulates C. albicans morphogenesis and virulence, and explore the potential of targeting fungal Hsp90 as a therapeutic strategy to combat fungal infections.
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Affiliation(s)
- Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
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8
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Sharma C, Kadosh D. Post-transcriptional control of antifungal resistance in human fungal pathogens. Crit Rev Microbiol 2023; 49:469-484. [PMID: 35634915 PMCID: PMC9766424 DOI: 10.1080/1040841x.2022.2080527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 05/10/2022] [Accepted: 05/17/2022] [Indexed: 11/03/2022]
Abstract
Global estimates suggest that over 300 million individuals of all ages are affected by serious fungal infections every year, culminating in about 1.7 million deaths. The societal and economic burden on the public health sector due to opportunistic fungal pathogens is quite significant, especially among immunocompromised patients. Despite the high clinical significance of these infectious agents, treatment options are limited with only three major classes of antifungal drugs approved for use. Clinical management of fungal diseases is further compromised by the emergence of antifungal resistant strains. Transcriptional and genetic mechanisms that control drug resistance in human fungal pathogens are well-studied and include drug target alteration, upregulation of drug efflux pumps as well as changes in drug affinity and abundance of target proteins. In this review, we highlight several recently discovered novel post-transcriptional mechanisms that control antifungal resistance, which involve regulation at the translational, post-translational, epigenetic, and mRNA stability levels. The discovery of many of these novel mechanisms has opened new avenues for the development of more effective antifungal treatment strategies and new insights, perspectives, and future directions that will facilitate this process are discussed.
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Affiliation(s)
- Cheshta Sharma
- Department of Microbiology, Immunology and Molecular Genetics University of Texas Health Science Center at San Antonio, San Antonio, TX
| | - David Kadosh
- Department of Microbiology, Immunology and Molecular Genetics University of Texas Health Science Center at San Antonio, San Antonio, TX
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9
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Li C, Tao L, Guan G, Guan Z, Perry AM, Hu T, Bing J, Xu M, Nobile CJ, Huang G. Atmospheric humidity regulates same-sex mating in Candida albicans through the trehalose and osmotic signaling pathways. SCIENCE CHINA. LIFE SCIENCES 2023; 66:1915-1929. [PMID: 37118508 PMCID: PMC10631464 DOI: 10.1007/s11427-023-2309-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/01/2023] [Indexed: 04/30/2023]
Abstract
Sexual reproduction is prevalent in eukaryotic organisms and plays a critical role in the evolution of new traits and in the generation of genetic diversity. Environmental factors often have a direct impact on the occurrence and frequency of sexual reproduction in fungi. The regulatory effects of atmospheric relative humidity (RH) on sexual reproduction and pathogenesis in plant fungal pathogens and in soil fungi have been extensively investigated. However, the knowledge of how RH regulates the lifecycles of human fungal pathogens is limited. In this study, we report that low atmospheric RH promotes the development of mating projections and same-sex (homothallic) mating in the human fungal pathogen Candida albicans. Low RH causes water loss in C. albicans cells, which results in osmotic stress and the generation of intracellular reactive oxygen species (ROS) and trehalose. The water transporting aquaporin Aqy1, and the G-protein coupled receptor Gpr1 function as cell surface sensors of changes in atmospheric humidity. Perturbation of the trehalose metabolic pathway by inactivating trehalose synthase or trehalase promotes same-sex mating in C. albicans by increasing osmotic or ROS stresses, respectively. Intracellular trehalose and ROS signal the Hog1-osmotic and Hsf1-Hsp90 signaling pathways to regulate the mating response. We, therefore, propose that the cell surface sensors Aqy1 and Gpr1, intracellular trehalose and ROS, and the Hog1-osmotic and Hsf1-Hsp90 signaling pathways function coordinately to regulate sexual mating in response to low atmospheric RH conditions in C. albicans.
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Affiliation(s)
- Chao Li
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Li Tao
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Guobo Guan
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zhangyue Guan
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Austin M Perry
- Department of Molecular and Cell Biology, University of California, Merced, Merced, CA, 95343, USA
- Quantitative and Systems Biology Graduate Program, University of California, Merced, Merced, CA, 95343, USA
| | - Tianren Hu
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Jian Bing
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Ming Xu
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China
| | - Clarissa J Nobile
- Department of Molecular and Cell Biology, University of California, Merced, Merced, CA, 95343, USA
- Health Sciences Research Institute, University of California, Merced, Merced, CA, 95343, USA
| | - Guanghua Huang
- Department of Infectious Diseases, Huashan Hospital, Shanghai Institute of Infectious Disease and Biosecurity and State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, 200438, China.
- Shanghai Engineering Research Center of Industrial Microorganisms, Shanghai, 200438, China.
- Shanghai Huashen Institute of Microbes and Infections, Shanghai, 200052, China.
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10
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Lee YS, Chen X, Widiyanto TW, Orihara K, Shibata H, Kajiwara S. Curcumin affects function of Hsp90 and drug efflux pump of Candida albicans. Front Cell Infect Microbiol 2022; 12:944611. [PMID: 36237434 PMCID: PMC9551236 DOI: 10.3389/fcimb.2022.944611] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 09/07/2022] [Indexed: 11/13/2022] Open
Abstract
Candida albicans is a pathogenic yeast that causes candidiasis in immunocompromised patients. The overuse of antifungal drugs has led to the development of resistance to such drugs by this fungus, which is a major challenge in antifungal chemotherapy. One approach to this problem involves the utilization of new natural products as an alternative source of antifungals. Curcumin, one such natural product, has been widely studied as a drug candidate and is reported to exhibit antifungal activity against C. albicans. Although studies of the mechanism of curcumin against human cancer cells have shown that it inhibits heat shock protein 90 (Hsp90), little is known about its function against C. albicans. In this paper, using a doxycycline-mediated HSP90 strain and an HSP90-overexpressing strain of C. albicans, we demonstrated that the curcumin triggered a decrease in Hsp90 by affecting it at the post-transcriptional level. This also led to the downregulation of HOG1 and CDR1, resulting in a reduction of the stress response and efflux pump activity of C. albicans. However, the inhibition of HSP90 by curcumin was not due to the inhibition of transcription factors HSF1 or AHR1. We also found that curcumin can not only decrease the transcriptional expression of CDR1, but also inhibit the efflux pump activity of Cdr1. Hence, we conclude that disruption of HSP90 by curcumin could impair cell growth, stress responses and efflux pump activity of C. albicans.
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Affiliation(s)
- Yean Sheng Lee
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Xinyue Chen
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | | | - Kanami Orihara
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | | | - Susumu Kajiwara
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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11
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Cantrell JM, Chung CH, Chandrasekaran S. Machine learning to design antimicrobial combination therapies: promises and pitfalls. Drug Discov Today 2022; 27:1639-1651. [DOI: 10.1016/j.drudis.2022.04.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 01/20/2022] [Accepted: 04/04/2022] [Indexed: 01/13/2023]
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12
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Iyer KR, Robbins N, Cowen LE. The role of Candida albicans stress response pathways in antifungal tolerance and resistance. iScience 2022; 25:103953. [PMID: 35281744 PMCID: PMC8905312 DOI: 10.1016/j.isci.2022.103953] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Human fungal pathogens are the causative agents of devastating diseases across the globe, and the increasing prevalence of drug resistance threatens to undermine the already limited treatment options. One prominent pathogen is the opportunistic fungus Candida albicans, which can cause both superficial and serious systemic infections in immunocompromised individuals. C. albicans antifungal drug resistance and antifungal tolerance are supported by diverse and expansive cellular stress response pathways. Some of the major players are the Ca2+-calmodulin-activated phosphatase calcineurin, the protein kinase C cell wall integrity pathway, and the molecular chaperone heat shock protein 90. Beyond these core signal transducers, several other enzymes and transcription factors have been implicated in both tolerance and resistance. Here, we highlight some of the major stress response pathways, key advances in identifying chemical matter to inhibit these pathways, and implications for C. albicans persistence in the host. Candida albicans can cause superficial and serious systemic infections in humans Stress response pathways regulate C. albicans antifungal resistance and tolerance Stress response regulators include calcineurin, Pkc1, Hsp90, and many others Stress response inhibitors could reduce the likelihood of fungi persisting in humans
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Affiliation(s)
- Kali R. Iyer
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, MaRS Centre, West Tower, Room 1638, Toronto, ON M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, MaRS Centre, West Tower, Room 1638, Toronto, ON M5G 1M1, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, MaRS Centre, West Tower, Room 1638, Toronto, ON M5G 1M1, Canada
- Corresponding author
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13
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Unmasking of CgYor1-Dependent Azole Resistance Mediated by Target of Rapamycin (TOR) and Calcineurin Signaling in Candida glabrata. mBio 2022; 13:e0354521. [PMID: 35038899 PMCID: PMC8764518 DOI: 10.1128/mbio.03545-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In this study, 18 predicted membrane-localized ABC transporters of Candida glabrata were deleted individually to create a minilibrary of knockouts (KO). The transporter KOs were analyzed for their susceptibility toward antimycotic drugs. Although CgYOR1 has previously been reported to be upregulated in various azole-resistant clinical isolates of C. glabrata, deletion of this gene did not change the susceptibility to any of the tested azoles. Additionally, Cgyor1Δ showed no change in susceptibility toward oligomycin, which is otherwise a well-known substrate of Yor1 in other yeasts. The role of CgYor1 in azole susceptibility only became evident when the major transporter CgCDR1 gene was deleted. However, under nitrogen-depleted conditions, Cgyor1Δ demonstrated an azole-susceptible phenotype, independent of CgCdr1. Notably, Cgyor1Δ cells also showed increased susceptibility to target of rapamycin (TOR) and calcineurin inhibitors. Moreover, increased phytoceramide levels in Cgyor1Δ and the deletions of regulators downstream of TOR and the calcineurin signaling cascade (Cgypk1Δ, Cgypk2Δ, Cgckb1Δ, and Cgckb2Δ) in the Cgyor1Δ background and their associated fluconazole (FLC) susceptibility phenotypes confirmed their involvement. Collectively, our findings show that TOR and calcineurin signaling govern CgYor1-mediated azole susceptibility in C. glabrata. IMPORTANCE The increasing incidence of Candida glabrata infections in the last 40 years is a serious concern worldwide. These infections are usually associated with intrinsic azole resistance and increasing echinocandin resistance. Efflux pumps, especially ABC transporter upregulation, are one of the prominent mechanisms of azole resistance; however, only a few of them are characterized. In this study, we analyzed the mechanisms of azole resistance due to a multidrug resistance-associated protein (MRP) subfamily ABC transporter, CgYor1. We demonstrate for the first time that CgYor1 does not transport oligomycin but is involved in azole resistance. Under normal growing conditions its function is masked by major transporter CgCdr1; however, under nitrogen-depleted conditions, it displays its azole resistance function independently. Moreover, we propose that the azole susceptibility due to removal of CgYor1 is not due to its transport function but involves modulation of TOR and calcineurin cascades.
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OUP accepted manuscript. Brief Funct Genomics 2022; 21:243-269. [DOI: 10.1093/bfgp/elac007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 11/14/2022] Open
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15
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Crunden JL, Diezmann S. Hsp90 interaction networks in fungi-tools and techniques. FEMS Yeast Res 2021; 21:6413543. [PMID: 34718512 PMCID: PMC8599792 DOI: 10.1093/femsyr/foab054] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 10/26/2021] [Indexed: 01/01/2023] Open
Abstract
Heat-shock protein 90 (Hsp90) is a central regulator of cellular proteostasis. It stabilizes numerous proteins that are involved in fundamental processes of life, including cell growth, cell-cycle progression and the environmental response. In addition to stabilizing proteins, Hsp90 governs gene expression and controls the release of cryptic genetic variation. Given its central role in evolution and development, it is important to identify proteins and genes that interact with Hsp90. This requires sophisticated genetic and biochemical tools, including extensive mutant collections, suitable epitope tags, proteomics approaches and Hsp90-specific pharmacological inhibitors for chemogenomic screens. These usually only exist in model organisms, such as the yeast Saccharomyces cerevisiae. Yet, the importance of other fungal species, such as Candida albicans and Cryptococcus neoformans, as serious human pathogens accelerated the development of genetic tools to study their virulence and stress response pathways. These tools can also be exploited to map Hsp90 interaction networks. Here, we review tools and techniques for Hsp90 network mapping available in different fungi and provide a summary of existing mapping efforts. Mapping Hsp90 networks in fungal species spanning >500 million years of evolution provides a unique vantage point, allowing tracking of the evolutionary history of eukaryotic Hsp90 networks.
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Affiliation(s)
- Julia L Crunden
- School of Cellular and Molecular Medicine, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Stephanie Diezmann
- School of Cellular and Molecular Medicine, University of Bristol, University Walk, Bristol BS8 1TD, UK
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Razzaq I, Berg MD, Jiang Y, Genereaux J, Uthayakumar D, Kim GH, Agyare-Tabbi M, Halder V, Brandl CJ, Lajoie P, Shapiro RS. The SAGA and NuA4 component Tra1 regulates Candida albicans drug resistance and pathogenesis. Genetics 2021; 219:iyab131. [PMID: 34849885 PMCID: PMC8633099 DOI: 10.1093/genetics/iyab131] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/02/2021] [Indexed: 11/14/2022] Open
Abstract
Candida albicans is the most common cause of death from fungal infections. The emergence of resistant strains reducing the efficacy of first-line therapy with echinocandins, such as caspofungin calls for the identification of alternative therapeutic strategies. Tra1 is an essential component of the SAGA and NuA4 transcriptional co-activator complexes. As a PIKK family member, Tra1 is characterized by a C-terminal phosphoinositide 3-kinase domain. In Saccharomyces cerevisiae, the assembly and function of SAGA and NuA4 are compromised by a Tra1 variant (Tra1Q3) with three arginine residues in the putative ATP-binding cleft changed to glutamine. Whole transcriptome analysis of the S. cerevisiae tra1Q3 strain highlights Tra1's role in global transcription, stress response, and cell wall integrity. As a result, tra1Q3 increases susceptibility to multiple stressors, including caspofungin. Moreover, the same tra1Q3 allele in the pathogenic yeast C. albicans causes similar phenotypes, suggesting that Tra1 broadly mediates the antifungal response across yeast species. Transcriptional profiling in C. albicans identified 68 genes that were differentially expressed when the tra1Q3 strain was treated with caspofungin, as compared to gene expression changes induced by either tra1Q3 or caspofungin alone. Included in this set were genes involved in cell wall maintenance, adhesion, and filamentous growth. Indeed, the tra1Q3 allele reduces filamentation and other pathogenesis traits in C. albicans. Thus, Tra1 emerges as a promising therapeutic target for fungal infections.
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Affiliation(s)
- Iqra Razzaq
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G2W1, Canada
| | - Matthew D Berg
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Yuwei Jiang
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Julie Genereaux
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Deeva Uthayakumar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G2W1, Canada
| | - Grace H Kim
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G2W1, Canada
| | - Michelle Agyare-Tabbi
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G2W1, Canada
| | - Viola Halder
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G2W1, Canada
| | - Christopher J Brandl
- Department of Biochemistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Patrick Lajoie
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1G2W1, Canada
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Alaalm L, Crunden JL, Butcher M, Obst U, Whealy R, Williamson CE, O'Brien HE, Schaffitzel C, Ramage G, Spencer J, Diezmann S. Identification and Phenotypic Characterization of Hsp90 Phosphorylation Sites That Modulate Virulence Traits in the Major Human Fungal Pathogen Candida albicans. Front Cell Infect Microbiol 2021; 11:637836. [PMID: 34513723 PMCID: PMC8431828 DOI: 10.3389/fcimb.2021.637836] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 05/24/2021] [Indexed: 01/13/2023] Open
Abstract
The highly conserved, ubiquitous molecular chaperone Hsp90 is a key regulator of cellular proteostasis and environmental stress responses. In human pathogenic fungi, which kill more than 1.6 million patients each year worldwide, Hsp90 governs cellular morphogenesis, drug resistance, and virulence. Yet, our understanding of the regulatory mechanisms governing fungal Hsp90 function remains sparse. Post-translational modifications are powerful components of nature’s toolbox to regulate protein abundance and function. Phosphorylation in particular is critical in many cellular signaling pathways and errant phosphorylation can have dire consequences for the cell. In the case of Hsp90, phosphorylation affects its stability and governs its interactions with co-chaperones and clients. Thereby modulating the cell’s ability to cope with environmental stress. Candida albicans, one of the leading human fungal pathogens, causes ~750,000 life-threatening invasive infections worldwide with unacceptably high mortality rates. Yet, it remains unknown if and how Hsp90 phosphorylation affects C. albicans virulence traits. Here, we show that phosphorylation of Hsp90 is critical for expression of virulence traits. We combined proteomics, molecular evolution analyses and structural modeling with molecular biology to characterize the role of Hsp90 phosphorylation in this non-model pathogen. We demonstrated that phosphorylation negatively affects key virulence traits, such as the thermal stress response, morphogenesis, and drug susceptibility. Our results provide the first record of a specific Hsp90 phosphorylation site acting as modulator of fungal virulence. Post-translational modifications of Hsp90 could prove valuable in future exploitations as antifungal drug targets.
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Affiliation(s)
- Leenah Alaalm
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom
| | - Julia L Crunden
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Mark Butcher
- School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, United Kingdom
| | - Ulrike Obst
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Ryann Whealy
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | | | - Heath E O'Brien
- MRC Centre for Neuropsychiatric Genetics & Genomics, Division of Psychological Medicine & Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom
| | | | - Gordon Ramage
- School of Medicine, Dentistry and Nursing, University of Glasgow, Glasgow, United Kingdom
| | - James Spencer
- School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
| | - Stephanie Diezmann
- Department of Biology & Biochemistry, University of Bath, Bath, United Kingdom.,School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
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18
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Germination of a Field: Women in Candida albicans Research. CURRENT CLINICAL MICROBIOLOGY REPORTS 2021. [DOI: 10.1007/s40588-021-00169-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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19
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Halder V, McDonnell B, Uthayakumar D, Usher J, Shapiro RS. Genetic interaction analysis in microbial pathogens: unravelling networks of pathogenesis, antimicrobial susceptibility and host interactions. FEMS Microbiol Rev 2021; 45:fuaa055. [PMID: 33145589 DOI: 10.1093/femsre/fuaa055] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 10/16/2020] [Indexed: 12/13/2022] Open
Abstract
Genetic interaction (GI) analysis is a powerful genetic strategy that analyzes the fitness and phenotypes of single- and double-gene mutant cells in order to dissect the epistatic interactions between genes, categorize genes into biological pathways, and characterize genes of unknown function. GI analysis has been extensively employed in model organisms for foundational, systems-level assessment of the epistatic interactions between genes. More recently, GI analysis has been applied to microbial pathogens and has been instrumental for the study of clinically important infectious organisms. Here, we review recent advances in systems-level GI analysis of diverse microbial pathogens, including bacterial and fungal species. We focus on important applications of GI analysis across pathogens, including GI analysis as a means to decipher complex genetic networks regulating microbial virulence, antimicrobial drug resistance and host-pathogen dynamics, and GI analysis as an approach to uncover novel targets for combination antimicrobial therapeutics. Together, this review bridges our understanding of GI analysis and complex genetic networks, with applications to diverse microbial pathogens, to further our understanding of virulence, the use of antimicrobial therapeutics and host-pathogen interactions. .
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Affiliation(s)
- Viola Halder
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Brianna McDonnell
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Deeva Uthayakumar
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
| | - Jane Usher
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
| | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, ON, N1G 2W1, Canada
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20
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Lee Y, Puumala E, Robbins N, Cowen LE. Antifungal Drug Resistance: Molecular Mechanisms in Candida albicans and Beyond. Chem Rev 2021; 121:3390-3411. [PMID: 32441527 PMCID: PMC8519031 DOI: 10.1021/acs.chemrev.0c00199] [Citation(s) in RCA: 340] [Impact Index Per Article: 113.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fungal infections are a major contributor to infectious disease-related deaths across the globe. Candida species are among the most common causes of invasive mycotic disease, with Candida albicans reigning as the leading cause of invasive candidiasis. Given that fungi are eukaryotes like their human host, the number of unique molecular targets that can be exploited for antifungal development remains limited. Currently, there are only three major classes of drugs approved for the treatment of invasive mycoses, and the efficacy of these agents is compromised by the development of drug resistance in pathogen populations. Notably, the emergence of additional drug-resistant species, such as Candida auris and Candida glabrata, further threatens the limited armamentarium of antifungals available to treat these serious infections. Here, we describe our current arsenal of antifungals and elaborate on the resistance mechanisms Candida species possess that render them recalcitrant to therapeutic intervention. Finally, we highlight some of the most promising therapeutic strategies that may help combat antifungal resistance, including combination therapy, targeting fungal-virulence traits, and modulating host immunity. Overall, a thorough understanding of the mechanistic principles governing antifungal drug resistance is fundamental for the development of novel therapeutics to combat current and emerging fungal threats.
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Affiliation(s)
- Yunjin Lee
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Emily Puumala
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, 661 University Avenue, Toronto, Ontario M5G 1M1, Canada
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21
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Horianopoulos LC, Kronstad JW. Chaperone Networks in Fungal Pathogens of Humans. J Fungi (Basel) 2021; 7:209. [PMID: 33809191 PMCID: PMC7998936 DOI: 10.3390/jof7030209] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 03/05/2021] [Accepted: 03/10/2021] [Indexed: 12/14/2022] Open
Abstract
The heat shock proteins (HSPs) function as chaperones to facilitate proper folding and modification of proteins and are of particular importance when organisms are subjected to unfavourable conditions. The human fungal pathogens are subjected to such conditions within the context of infection as they are exposed to human body temperature as well as the host immune response. Herein, the roles of the major classes of HSPs are briefly reviewed and their known contributions in human fungal pathogens are described with a focus on Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus. The Hsp90s and Hsp70s in human fungal pathogens broadly contribute to thermotolerance, morphological changes required for virulence, and tolerance to antifungal drugs. There are also examples of J domain co-chaperones and small HSPs influencing the elaboration of virulence factors in human fungal pathogens. However, there are diverse members in these groups of chaperones and there is still much to be uncovered about their contributions to pathogenesis. These HSPs do not act in isolation, but rather they form a network with one another. Interactions between chaperones define their specific roles and enhance their protein folding capabilities. Recent efforts to characterize these HSP networks in human fungal pathogens have revealed that there are unique interactions relevant to these pathogens, particularly under stress conditions. The chaperone networks in the fungal pathogens are also emerging as key coordinators of pathogenesis and antifungal drug tolerance, suggesting that their disruption is a promising strategy for the development of antifungal therapy.
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Affiliation(s)
| | - James W. Kronstad
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada;
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22
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Rosiana S, Zhang L, Kim GH, Revtovich AV, Uthayakumar D, Sukumaran A, Geddes-McAlister J, Kirienko NV, Shapiro RS. Comprehensive genetic analysis of adhesin proteins and their role in virulence of Candida albicans. Genetics 2021; 217:iyab003. [PMID: 33724419 PMCID: PMC8045720 DOI: 10.1093/genetics/iyab003] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 12/31/2020] [Indexed: 12/14/2022] Open
Abstract
Candida albicans is a microbial fungus that exists as a commensal member of the human microbiome and an opportunistic pathogen. Cell surface-associated adhesin proteins play a crucial role in C. albicans' ability to undergo cellular morphogenesis, develop robust biofilms, colonize, and cause infection in a host. However, a comprehensive analysis of the role and relationships between these adhesins has not been explored. We previously established a CRISPR-based platform for efficient generation of single- and double-gene deletions in C. albicans, which was used to construct a library of 144 mutants, comprising 12 unique adhesin genes deleted singly, and every possible combination of double deletions. Here, we exploit this adhesin mutant library to explore the role of adhesin proteins in C. albicans virulence. We perform a comprehensive, high-throughput screen of this library, using Caenorhabditis elegans as a simplified model host system, which identified mutants critical for virulence and significant genetic interactions. We perform follow-up analysis to assess the ability of high- and low-virulence strains to undergo cellular morphogenesis and form biofilms in vitro, as well as to colonize the C. elegans host. We further perform genetic interaction analysis to identify novel significant negative genetic interactions between adhesin mutants, whereby combinatorial perturbation of these genes significantly impairs virulence, more than expected based on virulence of the single mutant constituent strains. Together, this study yields important new insight into the role of adhesins, singly and in combinations, in mediating diverse facets of virulence of this critical fungal pathogen.
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Affiliation(s)
- Sierra Rosiana
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON NIG 2W1, Canada
| | - Liyang Zhang
- Department of BioSciences, Rice University, Houston, TX 77005, USA
| | - Grace H Kim
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON NIG 2W1, Canada
| | | | - Deeva Uthayakumar
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON NIG 2W1, Canada
| | - Arjun Sukumaran
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON NIG 2W1, Canada
| | | | | | - Rebecca S Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON NIG 2W1, Canada
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Retanal C, Ball B, Geddes-McAlister J. Post-Translational Modifications Drive Success and Failure of Fungal-Host Interactions. J Fungi (Basel) 2021; 7:jof7020124. [PMID: 33572187 PMCID: PMC7914884 DOI: 10.3390/jof7020124] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/04/2021] [Accepted: 02/08/2021] [Indexed: 12/11/2022] Open
Abstract
Post-translational modifications (PTMs) change the structure and function of proteins and regulate a diverse array of biological processes. Fungal pathogens rely on PTMs to modulate protein production and activity during infection, manipulate the host response, and ultimately, promote fungal survival. Given the high mortality rates of fungal infections on a global scale, along with the emergence of antifungal-resistant species, identifying new treatment options is critical. In this review, we focus on the role of PTMs (e.g., phosphorylation, acetylation, ubiquitination, glycosylation, and methylation) among the highly prevalent and medically relevant fungal pathogens, Candida spp., Aspergillus spp., and Cryptococcus spp. We explore the role of PTMs in fungal stress response and host adaptation, the use of PTMs to manipulate host cells and the immune system upon fungal invasion, and the importance of PTMs in conferring antifungal resistance. We also provide a critical view on the current knowledgebase, pose questions key to our understanding of the intricate roles of PTMs within fungal pathogens, and provide research opportunities to uncover new therapeutic strategies.
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Rocha MC, Minari K, Fabri JHTM, Kerkaert JD, Gava LM, da Cunha AF, Cramer RA, Borges JC, Malavazi I. Aspergillus fumigatus Hsp90 interacts with the main components of the cell wall integrity pathway and cooperates in heat shock and cell wall stress adaptation. Cell Microbiol 2021; 23:e13273. [PMID: 33010083 PMCID: PMC7855945 DOI: 10.1111/cmi.13273] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/12/2020] [Accepted: 09/27/2020] [Indexed: 12/18/2022]
Abstract
The initiation of Aspergillus fumigatus infection occurs via dormant conidia deposition into the airways. Therefore, conidial germination and subsequent hyphal extension and growth occur in a sustained heat shock (HS) environment promoted by the host. The cell wall integrity pathway (CWIP) and the essential eukaryotic chaperone Hsp90 are critical for fungi to survive HS. Although A. fumigatus is a thermophilic fungus, the mechanisms underpinning the HS response are not thoroughly described and important to define its role in pathogenesis, virulence and antifungal drug responses. Here, we investigate the contribution of the CWIP in A. fumigatus thermotolerance. We observed that the CWIP components PkcA, MpkA and RlmA are Hsp90 clients and that a PkcAG579R mutation abolishes this interaction. PkcAG579R also abolishes MpkA activation in the short-term response to HS. Biochemical and biophysical analyses indicated that Hsp90 is a dimeric functional ATPase, which has a higher affinity for ADP than ATP and prevents MpkA aggregation in vitro. Our data suggest that the CWIP is constitutively required for A. fumigatus to cope with the temperature increase found in the mammalian lung environment, emphasising the importance of this pathway in supporting thermotolerance and cell wall integrity.
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Affiliation(s)
- Marina Campos Rocha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Karine Minari
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | | | - Joshua D Kerkaert
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Lisandra Marques Gava
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Anderson Ferreira da Cunha
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
| | - Robert A Cramer
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Júlio César Borges
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - Iran Malavazi
- Departamento de Genética e Evolução, Centro de Ciências Biológicas e da Saúde, Universidade Federal de São Carlos, São Carlos, Brazil
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Systematic Analysis of the Lysine Crotonylome and Multiple Posttranslational Modification Analysis (Acetylation, Succinylation, and Crotonylation) in Candida albicans. mSystems 2021; 6:6/1/e01316-20. [PMID: 33500332 PMCID: PMC7842366 DOI: 10.1128/msystems.01316-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Candida albicans is an opportunistic pathogen that causes lethal fungal infections in immunocompromised patients. Lysine crotonylation is a newly discovered PTM (posttranslational modification) epigenetic type that may play a critical role in regulating gene expression. In this study, we used an antibody-enrichment approach along with LC-MS/MS to carry out a quantitative crotonylome analysis in C. albicans We found a total of 5,242 crotonylation sites and 1,584 crotonylated proteins among 9,038 proteins in this organism. Of these crotonylated proteins, a few unique crotonylated motifs are noted such as D and E in positions +1, +2, or +3 or K and R in positions +5 or +6, while A, E, F, G, P, W, and Y are in the -1 position or A, K, and R are found in positions -5, -6, -7, or -8. Functional analysis has shown that a majority of the crotonylated proteins are related to biosynthetic events and carbon metabolism. When combined with previously collected data on acetylation and succinylation, PPI (protein-protein interaction network) analysis reveals that proteins with functions in ribosomal biogenesis, oxidative phosphorylation, nucleus activity, and proteasome formation are heavily modified by these three PTM types. To the best of our knowledge, this is the first crotonylome study carried out in C. albicans and is an important step to a better understanding of the biological and pathogenic impact of PTM in C. albicans IMPORTANCE C. albicans is a kind of pathogen of fungal infections that is found worldwide. Lysine crotonylation of proteins as a recently discovered PTM (posttranslational modification) may have a critical role in regulating cells. We first carried out large-scale analysis of crotonylated proteome and multiple PTM analysis (acetylation, succinylation, and crotonylation), then drew a diagram to show multiple PTM sites on histones in C. albicans of our study. This study about crotonylome in human pathogenic fungi is a milestone that first and deeply investigates the functional analysis of crotonylated proteins in C. albicans, which marks an important start for further research.
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26
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Staniszewska M. Virulence Factors in Candida species. Curr Protein Pept Sci 2021; 21:313-323. [PMID: 31544690 DOI: 10.2174/1389203720666190722152415] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 06/06/2019] [Accepted: 07/14/2019] [Indexed: 02/08/2023]
Abstract
Fungal diseases are severe and have very high morbidity as well as up to 60% mortality for patients diagnosed with invasive fungal infection. In this review, in vitro and in vivo studies provided us with the insight into the role of Candida virulence factors that mediate their success as pathogens, such as: membrane and cell wall (CW) barriers, dimorphism, biofilm formation, signal transduction pathway, proteins related to stress tolerance, hydrolytic enzymes (e.g. proteases, lipases, haemolysins), and toxin production. The review characterized the virulence of clinically important C. albicans, C. parapsilosis, C. tropicalis, C. glabrata and C. krusei. Due to the white-opaque transition in the mating-type locus MTL-homozygous cells, C. albicans demonstrates an advantage over other less related species of Candida as a human commensal and pathogen. It was reviewed that Candida ergosterol biosynthesis genes play a role in cellular stress and are essential for Candida pathogenesis both in invasive and superficial infections. Hydrolases associated with CW are involved in the host-pathogen interactions. Adhesins are crucial in colonization and biofilm formation, an important virulence factor for candidiasis. Calcineurin is involved in membrane and CW stress as well as virulence. The hyphae-specific toxin, named candidalysin, invades mucosal cells facilitating fungal invasion into deeper tissues. Expression of this protein promotes resistance to neutrophil killing in candidiasis. The virulence factors provide immunostimulatory factors, activating dendric cells and promoting T cell infiltration and activation. Targeting virulence factors, can reduce the risk of resistance development in Candida infections.
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Affiliation(s)
- Monika Staniszewska
- Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw, Poland
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27
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Víglaš J, Olejníková P. Signalling mechanisms involved in stress response to antifungal drugs. Res Microbiol 2020; 172:103786. [PMID: 33038529 DOI: 10.1016/j.resmic.2020.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/24/2020] [Accepted: 10/01/2020] [Indexed: 01/28/2023]
Abstract
The emergence of antifungal resistance is a serious threat in the treatment of mycoses. The primary susceptible fungal cells may evolve a resistance after longer exposure to antifungal agents. The exposure itself causes stress condition, to which the fungus needs to adapt. This review provides detailed description of evolutionary conserved molecular mechanisms contributing to the adaptation response to stress caused by antifungal agents as well as their interconnection. The knowledge may help us to find new ways to delay the emergence of drug resistance as the same mechanisms are used regardless of what antifungal compound causes stress.
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Affiliation(s)
- Ján Víglaš
- Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 81237, Bratislava, Slovakia.
| | - Petra Olejníková
- Institute of Biochemistry and Microbiology, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinského 9, 81237, Bratislava, Slovakia.
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28
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Jia L, Kosgey JC, Wang J, Yang J, Nyamao RM, Zhao Y, Teng X, Gao L, Wabo MC, Vasilyeva NV, Fang Y, Zhang F. Antimicrobial and mechanism of antagonistic activity of Bacillus sp. A2 against pathogenic fungus and bacteria: The implication on honey's regulatory mechanism on host's microbiota. Food Sci Nutr 2020; 8:4857-4867. [PMID: 32994947 PMCID: PMC7500754 DOI: 10.1002/fsn3.1770] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 12/19/2022] Open
Abstract
Honey is thought to act against microbes and regulates microbiota balance, and this is mainly attributed to the enzymatic production of hydrogen peroxide, high osmolarity, and nonperoxidase factors, for example, lysozyme and botanical sources of nectar, while the effect of honey's probiotic is recently considered. The study of honey as source of beneficial microbes is understudied. The purpose of this study was to screen for the beneficial microorganisms in honey with antagonistic property against important pathogens and the mechanism of antimicrobial activity and thus play a beneficial role as probiotics. The results showed that one out of the fourteen bacterial isolates had antimicrobial activity and was identified as Bacillus Sp. A2 by 16S rRNA sequence and morphology. Antimicrobial activity of the isolate against C. albicans, E. coli, and S. aureus was confirmed by Agar well diffusion and liquid coculture assays, and the propagation of those microbes was significantly inhibited after treatment with the isolate Bacillus sp. A2 (p < .05) in comparison with untreated negative control and positive control (fluconazole, chloramphenicol, L. plantarum). The morphological changes including the distorted shape with indentations and leakages (SEM), damaged cell membrane, and cell wall with the disintegration and attachment of the Bacillus sp. A2 (TEM) in treated C. albicans were observed. Meanwhile, reactive oxygen species accumulation and decreased mitochondrial membrane potential were detected in treated C. albicans. These results revealed that the isolate Bacillus sp. A2 from honey has significant antimicrobial activity (p < .05) against C. albicans in comparison with untreated negative control and positive control L. plantarum, which depends on the accumulation of reactive oxygen species, mitochondrial damage, and the cell apoptosis. We concluded that the Bacillus sp. A2 possess the antimicrobial property, which may contribute to regulation of host's microbiota as a beneficial microbe or probiotic.
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Affiliation(s)
- Lina Jia
- Department of Microbiology WU Lien-Teh Institute Harbin Medical University Harbin China
| | - Janet Cheruiyot Kosgey
- School of biological and life sciences The Technical University of Kenya Nairobi Kenya
- Department of Microbiology WU Lien-Teh Institute Harbin Medical University Harbin China
| | - Jielin Wang
- Department of Microbiology WU Lien-Teh Institute Harbin Medical University Harbin China
| | - Jianxun Yang
- Department of Dermatology The 2nd Hospital of Harbin Medical University Harbin China
| | - Rose Magoma Nyamao
- Department of Microbiology WU Lien-Teh Institute Harbin Medical University Harbin China
- School of Medicine Kenyatta University Nairobi Kenya
| | - Yi Zhao
- Department of Microbiology WU Lien-Teh Institute Harbin Medical University Harbin China
| | - Xue Teng
- Department of Microbiology WU Lien-Teh Institute Harbin Medical University Harbin China
| | - Lei Gao
- Department of Microbiology WU Lien-Teh Institute Harbin Medical University Harbin China
| | | | - Natalia V Vasilyeva
- Department of Microbiology Kashkin Research Institute of Medical Mycology North-Western State Medical University named after I.I. Machnikov Saint Petersburg Russia
| | - Yong Fang
- Department of Microbiology WU Lien-Teh Institute Harbin Medical University Harbin China
| | - Fengmin Zhang
- Department of Microbiology WU Lien-Teh Institute Harbin Medical University Harbin China
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29
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Caplan T, Polvi EJ, Xie JL, Buckhalter S, Leach MD, Robbins N, Cowen LE. Functional Genomic Screening Reveals Core Modulators of Echinocandin Stress Responses in Candida albicans. Cell Rep 2019; 23:2292-2298. [PMID: 29791841 DOI: 10.1016/j.celrep.2018.04.084] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 03/28/2018] [Accepted: 04/18/2018] [Indexed: 01/28/2023] Open
Abstract
Candida albicans is a leading cause of death due to fungal infection. Treatment of systemic candidiasis often relies on echinocandins, which disrupt cell wall synthesis. Resistance is readily acquired via mutations in the drug target gene, FKS1. Both basal tolerance and resistance to echinocandins require cellular stress responses. We performed a systematic analysis of 3,030 C. albicans mutants to define circuitry governing cellular responses to echinocandins. We identified 16 genes for which deletion or transcriptional repression enhanced echinocandin susceptibility, including components of the Pkc1-MAPK signaling cascade. We discovered that the molecular chaperone Hsp90 is required for the stability of Pkc1 and Bck1, establishing key mechanisms through which Hsp90 mediates echinocandin resistance. We also discovered that perturbation of the CCT chaperonin complex causes enhanced echinocandin sensitivity, altered cell wall architecture, and aberrant septin localization. Thus, we provide insights into the mechanisms by which cellular chaperones enable crucial responses to echinocandin-induced stress.
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Affiliation(s)
- Tavia Caplan
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Elizabeth J Polvi
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Jinglin L Xie
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Shoshana Buckhalter
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Michelle D Leach
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada; Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1M1, Canada.
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30
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O’Meara TR, O’Meara MJ, Polvi EJ, Pourhaghighi MR, Liston SD, Lin ZY, Veri AO, Emili A, Gingras AC, Cowen LE. Global proteomic analyses define an environmentally contingent Hsp90 interactome and reveal chaperone-dependent regulation of stress granule proteins and the R2TP complex in a fungal pathogen. PLoS Biol 2019; 17:e3000358. [PMID: 31283755 PMCID: PMC6638986 DOI: 10.1371/journal.pbio.3000358] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 07/18/2019] [Accepted: 06/19/2019] [Indexed: 11/18/2022] Open
Abstract
Hsp90 is a conserved molecular chaperone that assists in the folding and function of diverse cellular regulators, with a profound impact on biology, disease, and evolution. As a central hub of protein interaction networks, Hsp90 engages with hundreds of protein-protein interactions within eukaryotic cells. These interactions include client proteins, which physically interact with Hsp90 and depend on the chaperone for stability or function, as well as co-chaperones and partner proteins that modulate chaperone function. Currently, there are no methods to accurately predict Hsp90 interactors and there has been considerable network rewiring over evolutionary time, necessitating experimental approaches to define the Hsp90 network in the species of interest. This is a pressing challenge for fungal pathogens, for which Hsp90 is a key regulator of stress tolerance, drug resistance, and virulence traits. To address this challenge, we applied a novel biochemical fractionation and quantitative proteomic approach to examine alterations to the proteome upon perturbation of Hsp90 in a leading human fungal pathogen, Candida albicans. In parallel, we performed affinity purification coupled to mass spectrometry to define physical interacting partners for Hsp90 and the Hsp90 co-chaperones and identified 164 Hsp90-interacting proteins, including 111 that are specific to the pathogen. We performed the first analysis of the Hsp90 interactome upon antifungal drug stress and demonstrated that Hsp90 stabilizes processing body (P-body) and stress granule proteins that contribute to drug tolerance. We also describe novel roles for Hsp90 in regulating posttranslational modification of the Rvb1-Rvb2-Tah1-Pih1 (R2TP) complex and the formation of protein aggregates in response to thermal stress. This study provides a global view of the Hsp90 interactome in a fungal pathogen, demonstrates the dynamic role of Hsp90 in response to environmental perturbations, and highlights a novel connection between Hsp90 and the regulation of mRNA-associated protein granules.
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Affiliation(s)
- Teresa R. O’Meara
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Matthew J. O’Meara
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
| | - Elizabeth J. Polvi
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - M. Reza Pourhaghighi
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
| | - Sean D. Liston
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Zhen-Yuan Lin
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Canada
| | - Amanda O. Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Andrew Emili
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Canada
- Department of Biology, Boston University School of Medicine, Boston, Massachusetts, United States of America
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts, United States of America
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Canada
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Canada
- * E-mail:
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31
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Guan G, Tao L, Yue H, Liang W, Gong J, Bing J, Zheng Q, Veri AO, Fan S, Robbins N, Cowen LE, Huang G. Environment-induced same-sex mating in the yeast Candida albicans through the Hsf1-Hsp90 pathway. PLoS Biol 2019; 17:e2006966. [PMID: 30865631 PMCID: PMC6415874 DOI: 10.1371/journal.pbio.2006966] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 02/13/2019] [Indexed: 12/14/2022] Open
Abstract
While sexual reproduction is pervasive in eukaryotic cells, the strategies employed by fungal species to achieve and complete sexual cycles is highly diverse and complex. Many fungi, including Saccharomyces cerevisiae and Schizosaccharomyces pombe, are homothallic (able to mate with their own mitotic descendants) because of homothallic switching (HO) endonuclease-mediated mating-type switching. Under laboratory conditions, the human fungal pathogen Candida albicans can undergo both heterothallic and homothallic (opposite- and same-sex) mating. However, both mating modes require the presence of cells with two opposite mating types (MTLa/a and α/α) in close proximity. Given the predominant clonal feature of this yeast in the human host, both opposite- and same-sex mating would be rare in nature. In this study, we report that glucose starvation and oxidative stress, common environmental stresses encountered by the pathogen, induce the development of mating projections and efficiently permit same-sex mating in C. albicans with an "a" mating type (MTLa/a). This induction bypasses the requirement for the presence of cells with an opposite mating type and allows efficient sexual mating between cells derived from a single progenitor. Glucose starvation causes an increase in intracellular oxidative species, overwhelming the Heat Shock transcription Factor 1 (Hsf1)- and Heat shock protein (Hsp)90-mediated stress-response pathway. We further demonstrate that Candida TransActivating protein 4 (Cta4) and Cell Wall Transcription factor 1 (Cwt1), downstream effectors of the Hsf1-Hsp90 pathway, regulate same-sex mating in C. albicans through the transcriptional control of the master regulator of a-type mating, MTLa2, and the pheromone precursor-encoding gene Mating α factor precursor (MFα). Our results suggest that mating could occur much more frequently in nature than was originally appreciated and that same-sex mating could be an important mode of sexual reproduction in C. albicans.
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Affiliation(s)
- Guobo Guan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Li Tao
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
| | - Huizhen Yue
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Weihong Liang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jiao Gong
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Jian Bing
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Qiushi Zheng
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Amanda O Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Shuru Fan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Guanghua Huang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan University, Shanghai, China
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32
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Rocha MC, Santos CA, Malavazi I. The Regulatory Function of the Molecular Chaperone Hsp90 in the Cell Wall Integrity of Pathogenic Fungi. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180820155807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Different signaling cascades including the Cell Wall Integrity (CWI), the High Osmolarity Glycerol (HOG) and the Ca2+/calcineurin pathways control the cell wall biosynthesis and remodeling in fungi. Pathogenic fungi, such as Aspergillus fumigatus and Candida albicans, greatly rely on these signaling circuits to cope with different sources of stress, including the cell wall stress evoked by antifungal drugs and the host’s response during infection. Hsp90 has been proposed as an important regulatory protein and an attractive target for antifungal therapy since it stabilizes major effector proteins that act in the CWI, HOG and Ca2+/calcineurin pathways. Data from the human pathogen C. albicans have provided solid evidence that loss-of-function of Hsp90 impairs the evolution of resistance to azoles and echinocandin drugs. In A. fumigatus, Hsp90 is also required for cell wall integrity maintenance, reinforcing a coordinated function of the CWI pathway and this essential molecular chaperone. In this review, we focus on the current information about how Hsp90 impacts the aforementioned signaling pathways and consequently the homeostasis and maintenance of the cell wall, highlighting this cellular event as a key mechanism underlying antifungal therapy based on Hsp90 inhibition.
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Affiliation(s)
- Marina Campos Rocha
- Departmento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, Brazil
| | - Camilla Alves Santos
- Departmento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, Brazil
| | - Iran Malavazi
- Departmento de Genetica e Evolucao, Centro de Ciencias Biologicas e da Saude, Universidade Federal de Sao Carlos, Sao Carlos, Brazil
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33
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Zheng YH, Ma YY, Ding Y, Chen XQ, Gao GX. An insight into new strategies to combat antifungal drug resistance. DRUG DESIGN DEVELOPMENT AND THERAPY 2018; 12:3807-3816. [PMID: 30464412 PMCID: PMC6225914 DOI: 10.2147/dddt.s185833] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Invasive fungal infections especially in immunocompromised patients represent a dominating cause of mortality. The most commonly used antifungal agents can be divided into three broad categories, including triazoles, echinocandins and polyenes. Antifungal resistance is on the increase, posing a growing threat to the stewardship of immunocompromised patients with fungal infections. The paucity of currently available antifungals leads to the rapid emergence of drug resistance and thus aggravates the refractoriness of invasive fungal infections. Therefore, deep exploration into mechanisms of drug resistance and search for new antifungal targets are required. This review highlights the therapeutic strategies targeting Hsp90, calcineurin, trehalose biosynthesis and sphingolipids biosynthesis, in an attempt to provide clinical evidence for overcoming drug resistance and to form the rationale for combination therapy of conventional antifungals and agents with novel mechanisms of action. What’s more, this review also gives a concise introduction of three new-fashioned antifungals, including carboxymethyl chitosan, silver nanoparticles and chromogranin A-N46.
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Affiliation(s)
- Yan-Hua Zheng
- Department of Hematology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China, ;
| | - Yue-Yun Ma
- Department of Clinical Laboratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Yi Ding
- Department of Pharmacy, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Xie-Qun Chen
- Department of Hematology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China, ;
| | - Guang-Xun Gao
- Department of Hematology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China, ;
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34
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Rizzolo K, Houry WA. Multiple functionalities of molecular chaperones revealed through systematic mapping of their interaction networks. J Biol Chem 2018; 294:2142-2150. [PMID: 30194284 DOI: 10.1074/jbc.tm118.002805] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Chaperones are a highly interactive group of proteins that function globally in many cellular processes involved in maintaining protein homeostasis. Traditional biochemical assays typically do not provide a complete view of the intricate networks through which chaperones collaborate to promote proteostasis. Recent advances in high-throughput systematic analyses of chaperone interactions have uncovered that chaperones display a remarkable cooperativity in their interactions with numerous client proteins. This cooperativity has been found to be a fundamental aspect of a properly functioning cell. Aberrant formation or improper regulation of these interactions can easily lead to disease states. Herein, we provide an overview of the use of large-scale interaction assays, whether physical (protein-protein) or genetic (epistatic), to study chaperone interaction networks. Importantly, we discuss the ongoing need for such studies to determine the mechanisms by which protein homeostasis is controlled in the cell.
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Affiliation(s)
- Kamran Rizzolo
- From the Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1M1 and
| | - Walid A Houry
- From the Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1M1 and .,the Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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35
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Antifungal tolerance is a subpopulation effect distinct from resistance and is associated with persistent candidemia. Nat Commun 2018; 9:2470. [PMID: 29941885 PMCID: PMC6018213 DOI: 10.1038/s41467-018-04926-x] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/05/2018] [Indexed: 11/23/2022] Open
Abstract
Tolerance to antifungal drug concentrations above the minimal inhibitory concentration (MIC) is rarely quantified, and current clinical recommendations suggest it should be ignored. Here, we quantify antifungal tolerance in Candida albicans isolates as the fraction of growth above the MIC, and find that it is distinct from susceptibility/resistance. Instead, tolerance is due to the slow growth of subpopulations of cells that overcome drug stress more efficiently than the rest of the population, and correlates inversely with intracellular drug accumulation. Many adjuvant drugs used in combination with fluconazole, a widely used fungistatic drug, reduce tolerance without affecting resistance. Accordingly, in an invertebrate infection model, adjuvant combination therapy is more effective than fluconazole in treating infections with highly tolerant isolates and does not affect infections with low tolerance isolates. Furthermore, isolates recovered from immunocompetent patients with persistent candidemia display higher tolerance than isolates readily cleared by fluconazole. Thus, tolerance correlates with, and may help predict, patient responses to fluconazole therapy. The authors show that antifungal tolerance, defined as the fraction of growth of a fungal pathogen above the minimal inhibitory concentration, is due to the slow growth of subpopulations of cells that overcome drug stress, and that high tolerance is often associated with persistent infections.
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36
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Jain P, Sethi SC, Pratyusha VA, Garai P, Naqvi N, Singh S, Pawar K, Puri N, Komath SS. Ras signaling activates glycosylphosphatidylinositol (GPI) anchor biosynthesis via the GPI- N-acetylglucosaminyltransferase (GPI-GnT) in Candida albicans. J Biol Chem 2018; 293:12222-12238. [PMID: 29907567 DOI: 10.1074/jbc.ra117.001225] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 04/17/2018] [Indexed: 01/08/2023] Open
Abstract
The ability of Candida albicans to switch between yeast to hyphal form is a property that is primarily associated with the invasion and virulence of this human pathogenic fungus. Several glycosylphosphatidylinositol (GPI)-anchored proteins are expressed only during hyphal morphogenesis. One of the major pathways that controls hyphal morphogenesis is the Ras-signaling pathway. We examine the cross-talk between GPI anchor biosynthesis and Ras signaling in C. albicans. We show that the first step of GPI biosynthesis is activated by Ras in C. albicans This is diametrically opposite to what is reported in Saccharomyces cerevisiae Of the two C. albicans Ras proteins, CaRas1 alone activates GPI-GnT activity; activity is further stimulated by constitutively activated CaRas1. CaRas1 localized to the cytoplasm or endoplasmic reticulum (ER) is sufficient for GPI-GnT activation. Of the six subunits of the GPI-N-acetylglucosaminyltransferase (GPI-GnT) that catalyze the first step of GPI biosynthesis, CaGpi2 is the key player involved in activating Ras signaling and hyphal morphogenesis. Activation of Ras signaling is independent of the catalytic competence of GPI-GnT. This too is unlike what is observed in S. cerevisiae where multiple subunits were identified as inhibiting Ras2. Fluorescence resonance energy transfer (FRET) studies indicate a specific physical interaction between CaRas1 and CaGpi2 in the ER, which would explain the ability of CaRas1 to activate GPI-GnT. CaGpi2, in turn, promotes activation of the Ras-signaling pathway and hyphal morphogenesis. The Cagpi2 mutant is also more susceptible to macrophage-mediated killing, and macrophage cells show better survival when co-cultured with Cagpi2.
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Affiliation(s)
- Priyanka Jain
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | | | | | - Pramita Garai
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Nilofer Naqvi
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Sonali Singh
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Kalpana Pawar
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Niti Puri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India
| | - Sneha Sudha Komath
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110 067, India.
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37
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Wambaugh MA, Brown JCS. High-throughput Identification of Synergistic Drug Combinations by the Overlap2 Method. J Vis Exp 2018. [PMID: 29863672 DOI: 10.3791/57241] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Although antimicrobial drugs have dramatically increased the lifespan and quality of life in the 20th century, antimicrobial resistance threatens our entire society's ability to treat systemic infections. In the United States alone, antibiotic-resistant infections kill approximately 23,000 people a year and cost around 20 billion USD in additional healthcare. One approach to combat antimicrobial resistance is combination therapy, which is particularly useful in the critical early stage of infection, before the infecting organism and its drug resistance profile have been identified. Many antimicrobial treatments use combination therapies. However, most of these combinations are additive, meaning that the combined efficacy is the same as the sum of the individual antibiotic efficacy. Some combination therapies are synergistic: the combined efficacy is much greater than additive. Synergistic combinations are particularly useful because they can inhibit the growth of antimicrobial drug resistant strains. However, these combinations are rare and difficult to identify. This is due to the sheer number of molecules needed to be tested in a pairwise manner: a library of 1,000 molecules has 1 million potential combinations. Thus, efforts have been made to predict molecules for synergy. This article describes our high-throughput method for predicting synergistic small molecule pairs known as the Overlap2 Method (O2M). O2M uses patterns from chemical-genetic datasets to identify mutants that are hypersensitive to each molecule in a synergistic pair but not to other molecules. The Brown lab exploits this growth difference by performing a high-throughput screen for molecules that inhibit the growth of mutant but not wild-type cells. The lab's work previously identified molecules that synergize with the antibiotic trimethoprim and the antifungal drug fluconazole using this strategy. Here, the authors present a method to screen for novel synergistic combinations, which can be altered for multiple microorganisms.
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Affiliation(s)
- Morgan A Wambaugh
- Microbiology and Immunology Division, Department of Pathology, University of Utah
| | - Jessica C S Brown
- Microbiology and Immunology Division, Department of Pathology, University of Utah;
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Veri AO, Miao Z, Shapiro RS, Tebbji F, O’Meara TR, Kim SH, Colazo J, Tan K, Vyas VK, Whiteway M, Robbins N, Wong KH, Cowen LE. Tuning Hsf1 levels drives distinct fungal morphogenetic programs with depletion impairing Hsp90 function and overexpression expanding the target space. PLoS Genet 2018; 14:e1007270. [PMID: 29590106 PMCID: PMC5873724 DOI: 10.1371/journal.pgen.1007270] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 02/22/2018] [Indexed: 12/24/2022] Open
Abstract
The capacity to respond to temperature fluctuations is critical for microorganisms to survive within mammalian hosts, and temperature modulates virulence traits of diverse pathogens. One key temperature-dependent virulence trait of the fungal pathogen Candida albicans is its ability to transition from yeast to filamentous growth, which is induced by environmental cues at host physiological temperature. A key regulator of temperature-dependent morphogenesis is the molecular chaperone Hsp90, which has complex functional relationships with the transcription factor Hsf1. Although Hsf1 controls global transcriptional remodeling in response to heat shock, its impact on morphogenesis remains unknown. Here, we establish an intriguing paradigm whereby overexpression or depletion of C. albicans HSF1 induces morphogenesis in the absence of external cues. HSF1 depletion compromises Hsp90 function, thereby driving filamentation. HSF1 overexpression does not impact Hsp90 function, but rather induces a dose-dependent expansion of Hsf1 direct targets that drives overexpression of positive regulators of filamentation, including Brg1 and Ume6, thereby bypassing the requirement for elevated temperature during morphogenesis. This work provides new insight into Hsf1-mediated environmentally contingent transcriptional control, implicates Hsf1 in regulation of a key virulence trait, and highlights fascinating biology whereby either overexpression or depletion of a single cellular regulator induces a profound developmental transition. For human pathogens, the capacity to respond to elevated temperature is required for survival, with elevated temperature in the form of fever as a conserved host response to defend against infection. One of the leading fungal pathogens of humans in Candida albicans, which is capable of growing in both a yeast and filamentous state. The ability to transition between these forms is a key virulence trait, and one that is highly temperature-dependent. A pivotal regulator of filamentous growth is the temperature-responsive molecular chaperone Hsp90, which has complex relationships with the transcription factor Hsf1. Although Hsf1 regulates changes in gene expression in response to heat shock, its impact on morphogenesis remains unknown. Here, we uncover an intriguing phenomenon whereby overexpression or depletion of C. albicans HSF1 induces morphogenesis. We observe that HSF1 depletion compromises Hsp90 function, thereby driving filamentation. In contrast, HSF1 overexpression induces a dose-dependent expansion of its transcriptional targets that drives overexpression of positive regulators of filamentous growth. This work illuminates novel mechanisms through which tuning the levels of an environmentally contingent transcription factor drives a key developmental program.
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Affiliation(s)
- Amanda O. Veri
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Zhengqiang Miao
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Rebecca S. Shapiro
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Faiza Tebbji
- Infectious Disease Research Centre, Université Laval, Quebec City, Quebec, Canada
| | - Teresa R. O’Meara
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Sang Hu Kim
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Juan Colazo
- Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Kaeling Tan
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Valmik K. Vyas
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts, United States of America
| | - Malcolm Whiteway
- Department of Biology, Concordia University, Montréal, Quebec, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Macau SAR, China
| | - Leah E. Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Ras hyperactivation versus overexpression: Lessons from Ras dynamics in Candida albicans. Sci Rep 2018; 8:5248. [PMID: 29588468 PMCID: PMC5869725 DOI: 10.1038/s41598-018-23187-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 03/06/2018] [Indexed: 12/25/2022] Open
Abstract
Ras signaling in response to environmental cues is critical for cellular morphogenesis in eukaryotes. This signaling is tightly regulated and its activation involves multiple players. Sometimes Ras signaling may be hyperactivated. In C. albicans, a human pathogenic fungus, we demonstrate that dynamics of hyperactivated Ras1 (Ras1G13V or Ras1 in Hsp90 deficient strains) can be reliably differentiated from that of normal Ras1 at (near) single molecule level using fluorescence correlation spectroscopy (FCS). Ras1 hyperactivation results in significantly slower dynamics due to actin polymerization. Activating actin polymerization by jasplakinolide can produce hyperactivated Ras1 dynamics. In a sterol-deficient hyperfilamentous GPI mutant of C. albicans too, Ras1 hyperactivation results from Hsp90 downregulation and causes actin polymerization. Hyperactivated Ras1 co-localizes with G-actin at the plasma membrane rather than with F-actin. Depolymerizing actin with cytochalasin D results in faster Ras1 dynamics in these and other strains that show Ras1 hyperactivation. Further, ergosterol does not influence Ras1 dynamics.
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40
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Cox MB, Johnson JL. Evidence for Hsp90 Co-chaperones in Regulating Hsp90 Function and Promoting Client Protein Folding. Methods Mol Biol 2018; 1709:397-422. [PMID: 29177674 DOI: 10.1007/978-1-4939-7477-1_28] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Molecular chaperones are a diverse group of highly conserved proteins that transiently interact with partially folded polypeptide chains during normal cellular processes such as protein translation, translocation, and disassembly of protein complexes. Prior to folding or after denaturation, hydrophobic residues that are normally sequestered within a folded protein are exposed to the aqueous environment and are prone to aggregation or misfolding. Multiple classes of molecular chaperones, such as Hsp70s and Hsp40s, recognize and transiently bind polypeptides with exposed hydrophobic stretches in order to prevent misfolding. Other types of chaperones, such as Hsp90, have more specialized functions in that they appear to interact with only a subset of cellular proteins. This chapter focuses on the role of Hsp90 and partner co-chaperones in promoting the folding and activation of a diverse group of proteins with critical roles in cellular signaling and function.
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Affiliation(s)
- Marc B Cox
- Department of Biological Sciences, University of Texas at El Paso and the Border Biomedical Research Center, El Paso, TX, 79968, USA
| | - Jill L Johnson
- Department of Biological Sciences and the Center for Reproductive Biology, University of Idaho, Moscow, ID, 83844-3051, USA.
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Khandelwal NK, Chauhan N, Sarkar P, Esquivel BD, Coccetti P, Singh A, Coste AT, Gupta M, Sanglard D, White TC, Chauvel M, d'Enfert C, Chattopadhyay A, Gaur NA, Mondal AK, Prasad R. Azole resistance in a Candida albicans mutant lacking the ABC transporter CDR6/ROA1 depends on TOR signaling. J Biol Chem 2017; 293:412-432. [PMID: 29158264 DOI: 10.1074/jbc.m117.807032] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 11/17/2017] [Indexed: 12/12/2022] Open
Abstract
ATP-binding cassette (ABC) transporters help export various substrates across the cell membrane and significantly contribute to drug resistance. However, a recent study reported an unusual case in which the loss of an ABC transporter in Candida albicans, orf19.4531 (previously named ROA1), increases resistance against antifungal azoles, which was attributed to an altered membrane potential in the mutant strain. To obtain further mechanistic insights into this phenomenon, here we confirmed that the plasma membrane-localized transporter (renamed CDR6/ROA1 for consistency with C. albicans nomenclature) could efflux xenobiotics such as berberine, rhodamine 123, and paraquat. Moreover, a CDR6/ROA1 null mutant, NKKY101, displayed increased susceptibility to these xenobiotics. Interestingly, fluorescence recovery after photobleaching (FRAP) results indicated that NKKY101 mutant cells exhibited increased plasma membrane rigidity, resulting in reduced azole accumulation and contributing to azole resistance. Transcriptional profiling revealed that ribosome biogenesis genes were significantly up-regulated in the NKKY101 mutant. As ribosome biogenesis is a well-known downstream phenomenon of target of rapamycin (TOR1) signaling, we suspected a link between ribosome biogenesis and TOR1 signaling in NKKY101. Therefore, we grew NKKY101 cells on rapamycin and observed TOR1 hyperactivation, which leads to Hsp90-dependent calcineurin stabilization and thereby increased azole resistance. This in vitro finding was supported by in vivo data from a mouse model of systemic infection in which NKKY101 cells led to higher fungal load after fluconazole challenge than wild-type cells. Taken together, our study uncovers a mechanism of azole resistance in C. albicans, involving increased membrane rigidity and TOR signaling.
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Affiliation(s)
- Nitesh Kumar Khandelwal
- From the School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.,the International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India, and
| | - Neeraj Chauhan
- Department of Microbiology, Biochemistry, and Molecular Genetics, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, New Jersey 07103
| | - Parijat Sarkar
- the CSIR-Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Brooke D Esquivel
- the School of Biological Sciences, Cell Biology, and Biophysics, University of Missouri, Kansas City, Missouri 64110
| | - Paola Coccetti
- the Department of Biotechnology and Biosciences, University of Milano-Bicocca, 20126 Milan, Italy.,SYSBIO, Centre of Systems Biology, 20126 Milan, Italy
| | - Ashutosh Singh
- From the School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.,the Department of Biochemistry, Lucknow University, Lucknow 226024, Uttar Pradesh, India
| | - Alix T Coste
- the Institute of Microbiology, University of Lausanne and University Hospital Center, Rue du Bugnon 48, Lausanne, CH-1011, Switzerland
| | - Meghna Gupta
- From the School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.,the Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158
| | - Dominique Sanglard
- the Institute of Microbiology, University of Lausanne and University Hospital Center, Rue du Bugnon 48, Lausanne, CH-1011, Switzerland
| | - Theodore C White
- the School of Biological Sciences, Cell Biology, and Biophysics, University of Missouri, Kansas City, Missouri 64110
| | - Murielle Chauvel
- the Département Génomes et Génétique, Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, INRA, 75015 Paris, France
| | - Christophe d'Enfert
- the Département Génomes et Génétique, Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, INRA, 75015 Paris, France
| | | | - Naseem A Gaur
- the International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India, and
| | - Alok Kumar Mondal
- From the School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Rajendra Prasad
- From the School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India, .,the Amity Institute of Integrative Sciences and Health, Amity University Haryana, Amity Education Valley Gurgaon-122413, India
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Yu Y, Hube B, Kämper J, Meyer V, Krappmann S. When green and red mycology meet: Impressions from an interdisciplinary forum on virulence mechanisms of phyto- and human-pathogenic fungi. Virulence 2017; 8:1435-1444. [PMID: 28723316 DOI: 10.1080/21505594.2017.1356502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Fungal infections pose a constant threat to plants and humans, but detailed knowledge about pathogenesis, immunity, or virulence is rather scarce. Due to the fact that a certain overlap in the armoury of infection exists between plant- and human-pathogenic fungi, an interdisciplinary forum was held in October 2016 at the Institute for Clinical Microbiology, Immunology and Hygiene in Erlangen under the organisational umbrella from two special interest groups of German microbial societies. Scientific exchange and intense discussion of this timely topic was fostered by bringing together renowned experts in their respective fields to present their thoughts and recent findings in the course of a plenary lecture and six themed sessions, accompanied by oral and poster contributions of young researchers. By targeting the topic of fungal virulence mechanisms from various angles and in the context of plant and human hosts, some common grounds and exciting perspectives could be deduced during this vibrant scientific event.
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Affiliation(s)
- Yidong Yu
- a Institute for Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen and Friedrich-Alexander University (FAU) Erlangen-Nürnberg , Erlangen , Bavaria , Germany
| | - Bernhard Hube
- b Department of Microbial Pathogenicity Mechanisms , Hans Knöll Institute , Jena , Thuringia , Germany
| | - Jörg Kämper
- c Department of Genetics , Institute of Applied Biosciences, Karlsruhe Institute of Technology , Karlsruhe , Baden-Wuerttemberg , Germany
| | - Vera Meyer
- d Institute of Biotechnology , Department of Applied and Molecular Microbiology, Technische Universität Berlin , Berlin , Germany
| | - Sven Krappmann
- a Institute for Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen and Friedrich-Alexander University (FAU) Erlangen-Nürnberg , Erlangen , Bavaria , Germany
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Xie JL, Bohovych I, Wong EOY, Lambert JP, Gingras AC, Khalimonchuk O, Cowen LE, Leach MD. Ydj1 governs fungal morphogenesis and stress response, and facilitates mitochondrial protein import via Mas1 and Mas2. MICROBIAL CELL 2017; 4:342-361. [PMID: 29082232 PMCID: PMC5657825 DOI: 10.15698/mic2017.10.594] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mitochondria underpin metabolism, bioenergetics, signalling, development and cell death in eukaryotes. Most of the ~1,000 yeast mitochondrial proteins are encoded in the nucleus and synthesised as precursors in the cytosol, with mitochondrial import facilitated by molecular chaperones. Here, we focus on the Hsp40 chaperone Ydj1 in the fungal pathogen Candida albicans, finding that it is localised to both the cytosol and outer mitochondrial membrane, and is required for cellular stress responses and for filamentation, a key virulence trait. Mapping the Ydj1 protein interaction network highlighted connections with co-chaperones and regulators of filamentation. Furthermore, the mitochondrial processing peptidases Mas1 and Mas2 were highly enriched for interaction with Ydj1. Additional analysis demonstrated that loss of MAS1, MAS2 or YDJ1 perturbs mitochondrial morphology and function. Deletion of YDJ1 impairs import of Su9, a protein that is cleaved to a mature form by Mas1 and Mas2. Thus, we highlight a novel role for Ydj1 in cellular morphogenesis, stress responses, and mitochondrial import in the fungal kingdom.
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Affiliation(s)
- Jinglin L Xie
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Iryna Bohovych
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA
| | - Erin O Y Wong
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Jean-Philippe Lambert
- Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON, M5G 1X5, Canada
| | - Anne-Claude Gingras
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada.,Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 600 University Avenue, Toronto, ON, M5G 1X5, Canada
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA.,Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA.,Fred & Pamela Buffett Cancer Center, Omaha, NE 68198, USA
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
| | - Michelle D Leach
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, AB25 2ZD, UK.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, M5S 1A8, Canada
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Oxidative Stress Response Tips the Balance in Aspergillus terreus Amphotericin B Resistance. Antimicrob Agents Chemother 2017; 61:AAC.00670-17. [PMID: 28739793 DOI: 10.1128/aac.00670-17] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 07/03/2017] [Indexed: 01/24/2023] Open
Abstract
In this study, we characterize the impact of antioxidative enzymes in amphotericin B (AmB)-resistant (ATR) and rare AmB-susceptible (ATS) clinical Aspergillus terreus isolates. We elucidate expression profiles of superoxide dismutase (SOD)- and catalase (CAT)-encoding genes, enzymatic activities of SODs, and superoxide anion production and signaling pathways involved in the oxidative stress response (OSR) in ATS and ATR strains under AmB treatment conditions. We show that ATR strains possess almost doubled basal SOD activity compared to that of ATS strains and that ATR strains exhibit an enhanced OSR, with significantly higher sod2 mRNA levels and significantly increased cat transcripts in ATR strains upon AmB treatment. In particular, inhibition of SOD and CAT proteins renders resistant isolates considerably susceptible to the drug in vitro In conclusion, this study shows that SODs and CATs are crucial for AmB resistance in A. terreus and that targeting the OSR might offer new treatment perspectives for resistant species.
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45
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Heat shock protein 90 localizes to the surface and augments virulence factors of Cryptococcus neoformans. PLoS Negl Trop Dis 2017; 11:e0005836. [PMID: 28783748 PMCID: PMC5559104 DOI: 10.1371/journal.pntd.0005836] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 08/16/2017] [Accepted: 07/26/2017] [Indexed: 12/15/2022] Open
Abstract
Background Thermotolerance is an essential attribute for pathogenesis of Cryptococcus as exemplified by the fact that only two species in the genus, which can grow at 37°C, are human pathogens. Species which have other virulence factors including capsule formation and melanisation, but lack the ability to propagate at 37°C are not pathogenic. In another related fungal pathogen, Candida albicans, heat shock protein 90 has been implicated to be a central player in commanding pathogenicity by governing yeast to hyphal transition and drug resistance. Exploring Hsp90 biology in Cryptococcus in context of thermotolerance may thus highlight important regulatory principles of virulence and open new therapeutic avenues. Methodology/Principal findings Hsp90 is involved in regulating thermotolerance in Cryptococcus as indicated by growth hypersensitivity at 37°C upon mild compromise of Hsp90 function relative to 25°C. Biochemical studies revealed a more potent inhibition of ATPase activity by pharmacological inhibitor 17-AAG at 37°C as compared to 25°C. Catalytic efficiency of the protein at 37°C was found to be 6.39×10−5μM-1. Furthermore, indirect immunofluorescence analysis using a specific antibody revealed cell surface localization of Hsp90 via ER Golgi classical secretory pathway. Hsp90 was found to be induced under capsule inducing conditions and Hsp90 inhibition led to decrease in capsular volume. Finally compromising Hsp90 function improved anidulafungin tolerance in Cryptococcus. Conclusions/Significance Our findings highlight that Hsp90 regulates pathogenicity of the fungus by myriad ways. Firstly, it is involved in mediating thermotolerance which implies targeting Hsp90 can abrogate thermotolerance and hence growth of the fungus. Secondly, this study provides the first report of biochemical properties of Hsp90 of a pathogenic fungus. Finally, since Hsp90 is localised at the cell wall, targeting cell surface Hsp90 can represent a novel strategy to combat this lethal infection. Thermotolerance is a pre-requisite for microbes to propagate successfully as human pathogens. In this study, we have investigated the role of Heat shock protein 90 in the pathogenesis and thermotolerance of C. neoformans, an environmental fungus that causes meningoencephalitis in humans. We show that thermotolerance of Cryptococcus critically depends on Hsp90 function as modest inhibition of Hsp90 function, robustly compromised growth of the fungus at 37°C with little effect at 25°C. This observation correlated with the fact that pharmacological inhibitor, 17-AAG also showed a more potent inhibition of ATPase activity of the protein at 37°C as indicated by a lower IC50 as compared to 25°C. Indirect immunofluorescence analysis using an antibody specific to CnHsp90 revealed cell surface localization of Hsp90. BFA sensitivity of such surface localization indicated involvement of ER-Golgi classical secretory pathway for this localization. Furthermore, inhibition of Hsp90 function not only abrogated the natural resistance of C. neoformans to cell wall targeting inhibitors echinocandins but also led to decrease in capsular assembly which is one of the classical virulence determinants of the pathogen. In all, this study provides the first detailed biochemical as well as functional insights into the role of Hsp90 in governing thermotolerance and augmenting virulence factors in C. neoformans.
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Kastora SL, Herrero‐de‐Dios C, Avelar GM, Munro CA, Brown AJP. Sfp1 and Rtg3 reciprocally modulate carbon source-conditional stress adaptation in the pathogenic yeast Candida albicans. Mol Microbiol 2017; 105:620-636. [PMID: 28574606 PMCID: PMC5575477 DOI: 10.1111/mmi.13722] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/25/2017] [Indexed: 11/27/2022]
Abstract
The pathogenicity of the clinically important yeast, Candida albicans, is dependent on robust responses to host-imposed stresses. These stress responses have generally been dissected in vitro at 30°C on artificial growth media that do not mimic host niches. Yet host inputs, such as changes in carbon source or temperature, are known to affect C. albicans stress adaptation. Therefore, we performed screens to identify novel regulators that promote stress resistance during growth on a physiologically relevant carboxylic acid and at elevated temperatures. These screens revealed that, under these 'non-standard' growth conditions, numerous uncharacterised regulators are required for stress resistance in addition to the classical Hog1, Cap1 and Cta4 stress pathways. In particular, two transcription factors (Sfp1 and Rtg3) promote stress resistance in a reciprocal, carbon source-conditional manner. SFP1 is induced in stressed glucose-grown cells, whereas RTG3 is upregulated in stressed lactate-grown cells. Rtg3 and Sfp1 regulate the expression of key stress genes such as CTA4, CAP1 and HOG1 in a carbon source-dependent manner. These mechanisms underlie the stress sensitivity of C. albicans sfp1 cells during growth on glucose, and rtg3 cells on lactate. The data suggest that C. albicans exploits environmentally contingent regulatory mechanisms to retain stress resistance during host colonisation.
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Affiliation(s)
- Stavroula L. Kastora
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medical Sciences, Institute of Medical SciencesUniversity of AberdeenAberdeenAB25 2ZDUK
| | - Carmen Herrero‐de‐Dios
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medical Sciences, Institute of Medical SciencesUniversity of AberdeenAberdeenAB25 2ZDUK
| | - Gabriela M. Avelar
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medical Sciences, Institute of Medical SciencesUniversity of AberdeenAberdeenAB25 2ZDUK
| | - Carol A. Munro
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medical Sciences, Institute of Medical SciencesUniversity of AberdeenAberdeenAB25 2ZDUK
| | - Alistair J. P. Brown
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medical Sciences, Institute of Medical SciencesUniversity of AberdeenAberdeenAB25 2ZDUK
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47
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Brown AJP, Cowen LE, di Pietro A, Quinn J. Stress Adaptation. Microbiol Spectr 2017; 5:10.1128/microbiolspec.FUNK-0048-2016. [PMID: 28721857 PMCID: PMC5701650 DOI: 10.1128/microbiolspec.funk-0048-2016] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Indexed: 01/21/2023] Open
Abstract
Fungal species display an extraordinarily diverse range of lifestyles. Nevertheless, the survival of each species depends on its ability to sense and respond to changes in its natural environment. Environmental changes such as fluctuations in temperature, water balance or pH, or exposure to chemical insults such as reactive oxygen and nitrogen species exert stresses that perturb cellular homeostasis and cause molecular damage to the fungal cell. Consequently, fungi have evolved mechanisms to repair this damage, detoxify chemical insults, and restore cellular homeostasis. Most stresses are fundamental in nature, and consequently, there has been significant evolutionary conservation in the nature of the resultant responses across the fungal kingdom and beyond. For example, heat shock generally induces the synthesis of chaperones that promote protein refolding, antioxidants are generally synthesized in response to an oxidative stress, and osmolyte levels are generally increased following a hyperosmotic shock. In this article we summarize the current understanding of these and other stress responses as well as the signaling pathways that regulate them in the fungi. Model yeasts such as Saccharomyces cerevisiae are compared with filamentous fungi, as well as with pathogens of plants and humans. We also discuss current challenges associated with defining the dynamics of stress responses and with the elaboration of fungal stress adaptation under conditions that reflect natural environments in which fungal cells may be exposed to different types of stresses, either sequentially or simultaneously.
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Affiliation(s)
- Alistair J P Brown
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Antonio di Pietro
- Departamento de Genética, Universidad de Córdoba, Campus de Rabanales, Edificio Gregor Mendel C5, 14071 Córdoba, Spain
| | - Janet Quinn
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, United Kingdom
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Wambaugh MA, Shakya VPS, Lewis AJ, Mulvey MA, Brown JCS. High-throughput identification and rational design of synergistic small-molecule pairs for combating and bypassing antibiotic resistance. PLoS Biol 2017; 15:e2001644. [PMID: 28632788 PMCID: PMC5478098 DOI: 10.1371/journal.pbio.2001644] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/17/2017] [Indexed: 02/06/2023] Open
Abstract
Antibiotic-resistant infections kill approximately 23,000 people and cost $20,000,000,000 each year in the United States alone despite the widespread use of small-molecule antimicrobial combination therapy. Antibiotic combinations typically have an additive effect: the efficacy of the combination matches the sum of the efficacies of each antibiotic when used alone. Small molecules can also act synergistically when the efficacy of the combination is greater than the additive efficacy. However, synergistic combinations are rare and have been historically difficult to identify. High-throughput identification of synergistic pairs is limited by the scale of potential combinations: a modest collection of 1,000 small molecules involves 1 million pairwise combinations. Here, we describe a high-throughput method for rapid identification of synergistic small-molecule pairs, the overlap2 method (O2M). O2M extracts patterns from chemical-genetic datasets, which are created when a collection of mutants is grown in the presence of hundreds of different small molecules, producing a precise set of phenotypes induced by each small molecule across the mutant set. The identification of mutants that show the same phenotype when treated with known synergistic molecules allows us to pinpoint additional molecule combinations that also act synergistically. As a proof of concept, we focus on combinations with the antibiotics trimethoprim and sulfamethizole, which had been standard treatment against urinary tract infections until widespread resistance decreased efficacy. Using O2M, we screened a library of 2,000 small molecules and identified several that synergize with the antibiotic trimethoprim and/or sulfamethizole. The most potent of these synergistic interactions is with the antiviral drug azidothymidine (AZT). We then demonstrate that understanding the molecular mechanism underlying small-molecule synergistic interactions allows the rational design of additional combinations that bypass drug resistance. Trimethoprim and sulfamethizole are both folate biosynthesis inhibitors. We find that this activity disrupts nucleotide homeostasis, which blocks DNA replication in the presence of AZT. Building on these data, we show that other small molecules that disrupt nucleotide homeostasis through other mechanisms (hydroxyurea and floxuridine) also act synergistically with AZT. These novel combinations inhibit the growth and virulence of trimethoprim-resistant clinical Escherichia coli and Klebsiella pneumoniae isolates, suggesting that they may be able to be rapidly advanced into clinical use. In sum, we present a generalizable method to screen for novel synergistic combinations, to identify particular mechanisms resulting in synergy, and to use the mechanistic knowledge to rationally design new combinations that bypass drug resistance.
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MESH Headings
- Animals
- Anti-Bacterial Agents/chemistry
- Anti-Bacterial Agents/pharmacology
- Anti-Bacterial Agents/therapeutic use
- Anti-Infective Agents, Urinary/chemistry
- Anti-Infective Agents, Urinary/pharmacology
- Anti-Infective Agents, Urinary/therapeutic use
- Bacterial Proteins/antagonists & inhibitors
- Bacterial Proteins/genetics
- Bacterial Proteins/metabolism
- Biological Assay
- Computational Biology
- Drug Design
- Drug Resistance, Multiple, Bacterial
- Drug Synergism
- Drug Therapy, Combination
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/metabolism
- Embryo, Nonmammalian/microbiology
- Escherichia coli/drug effects
- Escherichia coli/growth & development
- Escherichia coli/metabolism
- Escherichia coli Infections/drug therapy
- Escherichia coli Infections/metabolism
- Escherichia coli Infections/microbiology
- Folic Acid Antagonists/chemistry
- Folic Acid Antagonists/pharmacology
- Folic Acid Antagonists/therapeutic use
- High-Throughput Screening Assays
- Klebsiella Infections/drug therapy
- Klebsiella Infections/metabolism
- Klebsiella Infections/microbiology
- Klebsiella pneumoniae/drug effects
- Klebsiella pneumoniae/growth & development
- Klebsiella pneumoniae/metabolism
- Microbial Sensitivity Tests
- Mutation
- Mutation Rate
- Pattern Recognition, Automated
- Reverse Transcriptase Inhibitors/chemistry
- Reverse Transcriptase Inhibitors/pharmacology
- Reverse Transcriptase Inhibitors/therapeutic use
- Small Molecule Libraries
- Sulfamethizole/agonists
- Sulfamethizole/chemistry
- Sulfamethizole/pharmacology
- Sulfamethizole/therapeutic use
- Trimethoprim/agonists
- Trimethoprim/chemistry
- Trimethoprim/pharmacology
- Trimethoprim/therapeutic use
- Zebrafish/embryology
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Affiliation(s)
- Morgan A. Wambaugh
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Viplendra P. S. Shakya
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Adam J. Lewis
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Matthew A. Mulvey
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Jessica C. S. Brown
- Division of Microbiology and Immunology, Pathology Department, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
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49
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O'Meara TR, Robbins N, Cowen LE. The Hsp90 Chaperone Network Modulates Candida Virulence Traits. Trends Microbiol 2017; 25:809-819. [PMID: 28549824 DOI: 10.1016/j.tim.2017.05.003] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 04/28/2017] [Accepted: 05/02/2017] [Indexed: 11/30/2022]
Abstract
Hsp90 is a conserved molecular chaperone that facilitates the folding and function of client proteins. Hsp90 function is dynamically regulated by interactions with co-chaperones and by post-translational modifications. In the fungal pathogen Candida albicans, Hsp90 enables drug resistance and virulence by stabilizing diverse signal transducers. Here, we review studies that have unveiled regulators of Hsp90 function, as well as downstream effectors that govern the key virulence traits of morphogenesis and drug resistance. We highlight recent work mapping the Hsp90 genetic network in C. albicans under diverse environmental conditions, and how these interactions provide insight into circuitry important for drug resistance, morphogenesis, and virulence. Ultimately, elucidating the Hsp90 chaperone network will aid in the development of therapeutics to treat fungal disease.
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Affiliation(s)
- Teresa R O'Meara
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5G 1M1, Canada.
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50
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Yang DH, Jung KW, Bang S, Lee JW, Song MH, Floyd-Averette A, Festa RA, Ianiri G, Idnurm A, Thiele DJ, Heitman J, Bahn YS. Rewiring of Signaling Networks Modulating Thermotolerance in the Human Pathogen Cryptococcus neoformans. Genetics 2017; 205:201-219. [PMID: 27866167 PMCID: PMC5223503 DOI: 10.1534/genetics.116.190595] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 11/08/2016] [Indexed: 01/17/2023] Open
Abstract
Thermotolerance is a crucial virulence attribute for human pathogens, including the fungus Cryptococcus neoformans that causes fatal meningitis in humans. Loss of the protein kinase Sch9 increases C. neoformans thermotolerance, but its regulatory mechanism has remained unknown. Here, we studied the Sch9-dependent and Sch9-independent signaling networks modulating C. neoformans thermotolerance by using genome-wide transcriptome analysis and reverse genetic approaches. During temperature upshift, genes encoding for molecular chaperones and heat shock proteins were upregulated, whereas those for translation, transcription, and sterol biosynthesis were highly suppressed. In this process, Sch9 regulated basal expression levels or induced/repressed expression levels of some temperature-responsive genes, including heat shock transcription factor (HSF1) and heat shock proteins (HSP104 and SSA1). Notably, we found that the HSF1 transcript abundance decreased but the Hsf1 protein became transiently phosphorylated during temperature upshift. Nevertheless, Hsf1 is essential for growth and its overexpression promoted C. neoformans thermotolerance. Transcriptome analysis using an HSF1 overexpressing strain revealed a dual role of Hsf1 in the oxidative stress response and thermotolerance. Chromatin immunoprecipitation demonstrated that Hsf1 binds to the step-type like heat shock element (HSE) of its target genes more efficiently than to the perfect- or gap-type HSE. This study provides insight into the thermotolerance of C. neoformans by elucidating the regulatory mechanisms of Sch9 and Hsf1 through the genome-scale identification of temperature-dependent genes.
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Affiliation(s)
- Dong-Hoon Yang
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Kwang-Woo Jung
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Soohyun Bang
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Jang-Won Lee
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Min-Hee Song
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
| | - Anna Floyd-Averette
- Departments of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Richard A Festa
- Departments of Pharmacology and Cancer Biology and Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Giuseppe Ianiri
- Departments of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Alexander Idnurm
- School of BioSciences, University of Melbourne, Victoria 3010, Australia
| | - Dennis J Thiele
- Departments of Pharmacology and Cancer Biology and Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710
| | - Joseph Heitman
- Departments of Molecular Genetics and Microbiology, Medicine, and Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710
| | - Yong-Sun Bahn
- Department of Biotechnology, Yonsei University, Seoul 03722, Republic of Korea
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