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Zeng L, Huang Y, Tan J, Peng J, Hu N, Liu Q, Cao Y, Zhang Y, Chen J, Huang X. QCR7 affects the virulence of Candida albicans and the uptake of multiple carbon sources present in different host niches. Front Cell Infect Microbiol 2023; 13:1136698. [PMID: 36923588 PMCID: PMC10009220 DOI: 10.3389/fcimb.2023.1136698] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 02/09/2023] [Indexed: 03/02/2023] Open
Abstract
Background Candida albicans is a commensal yeast that may cause life-threatening infections. Studies have shown that the cytochrome b-c1 complex subunit 7 gene (QCR7) of C. albicans encodes a protein that forms a component of the mitochondrial electron transport chain complex III, making it an important target for studying the virulence of this yeast. However, to the best of our knowledge, the functions of QCR7 have not yet been characterized. Methods A QCR7 knockout strain was constructed using SN152, and BALb/c mice were used as model animals to determine the role of QCR7 in the virulence of C. albicans. Subsequently, the effects of QCR7 on mitochondrial functions and use of carbon sources were investigated. Next, its mutant biofilm formation and hyphal growth maintenance were compared with those of the wild type. Furthermore, the transcriptome of the qcr7Δ/Δ mutant was compared with that of the WT strain to explore pathogenic mechanisms. Results Defective QCR7 reduced recruitment of inflammatory cells and attenuated the virulence of C. albicans infection in vivo. Furthermore, the mutant influenced the use of multiple alternative carbon sources that exist in several host niches (GlcNAc, lactic acid, and amino acid, etc.). Moreover, it led to mitochondrial dysfunction. Furthermore, the QCR7 knockout strain showed defects in biofilm formation or the maintenance of filamentous growth. The overexpression of cell-surface-associated genes (HWP1, YWP1, XOG1, and SAP6) can restore defective virulence phenotypes and the carbon-source utilization of qcr7Δ/Δ. Conclusion This study provides new insights into the mitochondria-based metabolism of C. albicans, accounting for its virulence and the use of variable carbon sources that promote C. albicans to colonize host niches.
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Affiliation(s)
- Lingbing Zeng
- The First Affiliated Hospital of Nanchang University, School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yongcheng Huang
- School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
- Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang, China
| | - Junjun Tan
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Jun Peng
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Niya Hu
- The First Affiliated Hospital of Nanchang University, School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Qiong Liu
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - YanLi Cao
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Yuping Zhang
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Junzhu Chen
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
| | - Xiaotian Huang
- The First Affiliated Hospital of Nanchang University, School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
- Department of Medical Microbiology, Jiangxi Medical College, Nanchang University, Nanchang, China
- School of Public Health, Jiangxi Medical College, Nanchang University, Nanchang, China
- Jiangxi Provincial Key Laboratory of Preventive Medicine, Nanchang University, Nanchang, China
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Lv Q, Yan L, Wang J, Feng J, Gao L, Qiu L, Chao W, Qin YL, Jiang Y. Combined Transcriptome and Metabolome Analysis Reveals That the Potent Antifungal Pyrylium Salt Inhibits Mitochondrial Complex I in Candida albicans. Microbiol Spectr 2023; 11:e0320922. [PMID: 36790175 PMCID: PMC10100848 DOI: 10.1128/spectrum.03209-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 01/06/2023] [Indexed: 02/16/2023] Open
Abstract
Based on the structural modification of SM21, xy12, a new pyrylium salt derivative with enhanced antifungal activities, was synthesized. The MICs (MIC90) of xy12 against Candida albicans ranged from 0.125 to 0.25 μg/mL, about 2-fold lower than those of SM21. In addition, xy12 inhibited hypha and biofilm formation in C. albicans in a dose-dependent manner. A total of 3,454 differentially expressed genes and 260 differential metabolites were identified in the xy12-treated C. albicans by RNA-seq and non-targeted metabolomics. By integrating KEGG pathway enrichment analysis, we found that inhibition of oxidative phosphorylation was the important antifungal mechanism of action of xy12. Electron transport through mitochondrial respiratory complexes I to IV is the common process of oxidative phosphorylation. Compared with the sensitivity of the wild-type SC5314 to xy12, decreased sensitivities in mitochondrial complex I (CI)-deficient mutants and increased sensitivities in mitochondrial complex III- and IV-deficient mutants suggested that the antifungal effects of xy12 were dependent on CI. Consistently, xy12 exhibited antagonism with rotenone, an inhibitor of CI, and significantly inhibited the expression and activity of CI. Meanwhile, the phenotypes in the xy12-treated C. albicans were similar to those in the CI-deficient mutants, such as decreased ATP production, reduced mitochondrial membrane potential, loss of mitochondrial DNA, inability to utilize nonfermentative carbon sources, and decreased cell wall N-linked mannoproteins. Collectively, our results revealed that the pyrylium salt xy12 could constrain oxidative phosphorylation by inhibiting mitochondrial complex I in C. albicans, providing a novel lead compound for the development of mitochondria-targeted antifungal drugs. IMPORTANCE The development of new antifungal drugs is critical for solving the problem of antifungal resistance and expanding the limited variety of clinical antifungal drugs. Based on the modification of the pyrylium salt SM21, a new lead compound, xy12, was synthesized which was effective against Candida species both in vitro and in vivo. In this study, conjoined analysis of the transcriptome and metabolome elucidated the antifungal mechanism of action of xy12, which inhibited the activity of mitochondrial complex I in C. albicans. Targeting fungi-specific mitochondrial complex proteins has been reported as a promising antifungal strategy. Our study provided a new lead compound for targeting C. albicans mitochondrial complex I, which could be beneficial for discovering novel antifungal drugs.
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Affiliation(s)
- Quanzhen Lv
- School of Pharmacy, Naval Medical University, Shanghai, People’s Republic of China
| | - Lan Yan
- School of Pharmacy, Naval Medical University, Shanghai, People’s Republic of China
| | - Jinxin Wang
- School of Pharmacy, Naval Medical University, Shanghai, People’s Republic of China
| | - Jia Feng
- Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China
| | - Lu Gao
- Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China
| | - Lijuan Qiu
- School of Pharmacy, Naval Medical University, Shanghai, People’s Republic of China
| | - Wen Chao
- School of Pharmacy, Naval Medical University, Shanghai, People’s Republic of China
| | - Yu-Lin Qin
- Fudan University Minhang Hospital, Shanghai, People’s Republic of China
| | - Yuanying Jiang
- School of Pharmacy, Naval Medical University, Shanghai, People’s Republic of China
- Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, People’s Republic of China
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Zhang Y, Tang C, Zhang Z, Li S, Zhao Y, Weng L, Zhang H. Deletion of the ATP2 Gene in Candida albicans Blocks Its Escape From Macrophage Clearance. Front Cell Infect Microbiol 2021; 11:643121. [PMID: 33937095 PMCID: PMC8085345 DOI: 10.3389/fcimb.2021.643121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/30/2021] [Indexed: 11/28/2022] Open
Abstract
Macrophages provide the first-line defense against invasive fungal infections and, therefore, escape from macrophage becomes the basis for the establishment of Candida albicans invasive infection. Here, we found that deletion of ATP2 (atp2Δ/Δ) in C. albicans resulted in a dramatic decrease from 69.2% (WT) to 1.2% in the escape rate in vitro. The effect of ATP2 on macrophage clearance stands out among the genes currently known to affect clearance. In the normal mice, the atp2Δ/Δ cells were undetectable in major organs 72 h after systemic infection, while WT cells persisted in vivo. However, in the macrophage-depleted mice, atp2Δ/Δ could persist for 72 h at an amount comparable to that at 24 h. Regarding the mechanism, WT cells sustained growth and switched to hyphal form, which was more conducive to escape from macrophages, in media that mimic the glucose-deficient environment in macrophages. In contrast, atp2Δ/Δ cells can remained viable but were unable to complete morphogenesis in these media, resulting in them being trapped within macrophages in the yeast form. Meanwhile, atp2Δ/Δ cells were killed by oxidative stress in alternative carbon sources by 2- to 3-fold more than WT cells. Taken together, ATP2 deletion prevents C. albicans from escaping macrophage clearance, and therefore ATP2 has a functional basis as a drug target that interferes with macrophage clearance.
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Affiliation(s)
- Yishan Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Chuanyan Tang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Zhanpeng Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Shuixiu Li
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Yajing Zhao
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Luobei Weng
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Hong Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
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Mamouei Z, Singh S, Lemire B, Gu Y, Alqarihi A, Nabeela S, Li D, Ibrahim A, Uppuluri P. An evolutionarily diverged mitochondrial protein controls biofilm growth and virulence in Candida albicans. PLoS Biol 2021; 19:e3000957. [PMID: 33720927 PMCID: PMC8007014 DOI: 10.1371/journal.pbio.3000957] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 03/29/2021] [Accepted: 01/29/2021] [Indexed: 11/19/2022] Open
Abstract
A forward genetic screening approach identified orf19.2500 as a gene controlling Candida albicans biofilm dispersal and biofilm detachment. Three-dimensional (3D) protein modeling and bioinformatics revealed that orf19.2500 is a conserved mitochondrial protein, structurally similar to, but functionally diverged from, the squalene/phytoene synthases family. The C. albicans orf19.2500 is distinguished by 3 evolutionarily acquired stretches of amino acid inserts, absent from all other eukaryotes except a small number of ascomycete fungi. Biochemical assays showed that orf19.2500 is required for the assembly and activity of the NADH ubiquinone oxidoreductase Complex I (CI) of the respiratory electron transport chain (ETC) and was thereby named NDU1. NDU1 is essential for respiration and growth on alternative carbon sources, important for immune evasion, required for virulence in a mouse model of hematogenously disseminated candidiasis, and for potentiating resistance to antifungal drugs. Our study is the first report on a protein that sets the Candida-like fungi phylogenetically apart from all other eukaryotes, based solely on evolutionary "gain" of new amino acid inserts that are also the functional hub of the protein.
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Affiliation(s)
- Zeinab Mamouei
- David Geffen School of Medicine, University of California (UCLA), Los Angeles, California, United States of America
| | - Shakti Singh
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Bernard Lemire
- Department of Biochemistry, University of Alberta, Alberta, Canada
| | - Yiyou Gu
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Abdullah Alqarihi
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Sunna Nabeela
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Dongmei Li
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, United States of America
| | - Ashraf Ibrahim
- David Geffen School of Medicine, University of California (UCLA), Los Angeles, California, United States of America
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States of America
| | - Priya Uppuluri
- David Geffen School of Medicine, University of California (UCLA), Los Angeles, California, United States of America
- Division of Infectious Disease, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States of America
- * E-mail:
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5
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Song J, Zhou J, Zhang L, Li R. Mitochondria-Mediated Azole Drug Resistance and Fungal Pathogenicity: Opportunities for Therapeutic Development. Microorganisms 2020; 8:E1574. [PMID: 33066090 PMCID: PMC7600254 DOI: 10.3390/microorganisms8101574] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 10/09/2020] [Accepted: 10/09/2020] [Indexed: 12/16/2022] Open
Abstract
In recent years, the role of mitochondria in pathogenic fungi in terms of azole resistance and fungal pathogenicity has been a rapidly developing field. In this review, we describe the molecular mechanisms by which mitochondria are involved in regulating azole resistance and fungal pathogenicity. Mitochondrial function is involved in the regulation of drug efflux pumps at the transcriptional and posttranslational levels. On the one hand, defects in mitochondrial function can serve as the signal leading to activation of calcium signaling and the pleiotropic drug resistance pathway and, therefore, can globally upregulate the expression of drug efflux pump genes, leading to azole drug resistance. On the other hand, mitochondria also contribute to azole resistance through modulation of drug efflux pump localization and activity. Mitochondria further contribute to azole resistance through participating in iron homeostasis and lipid biosynthesis. Additionally, mitochondrial dynamics play an important role in azole resistance. Meanwhile, mitochondrial morphology is important for fungal virulence, playing roles in growth in stressful conditions in a host. Furthermore, there is a close link between mitochondrial respiration and fungal virulence, and mitochondrial respiration plays an important role in morphogenetic transition, hypoxia adaptation, and cell wall biosynthesis. Finally, we discuss the possibility for targeting mitochondrial factors for the development of antifungal therapies.
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Affiliation(s)
- Jinxing Song
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China;
- Shandong Provincial Key Laboratory of Infection and Immunity, Jinan 250012, China;
| | - Jingwen Zhou
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China;
| | - Lei Zhang
- Shandong Provincial Key Laboratory of Infection and Immunity, Jinan 250012, China;
| | - Rongpeng Li
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, China;
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Transcriptome Analyses of Candida albicans Biofilms, Exposed to Arachidonic Acid and Fluconazole, Indicates Potential Drug Targets. G3-GENES GENOMES GENETICS 2020; 10:3099-3108. [PMID: 32631950 PMCID: PMC7466979 DOI: 10.1534/g3.120.401340] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Candida albicans is an opportunistic yeast pathogen within the human microbiota with significant medical importance because of its pathogenic potential. The yeast produces highly resistant biofilms, which are crucial for maintaining infections. Though antifungals are available, their effectiveness is dwindling due to resistance. Alternate options that comprise the combination of existing azoles and polyunsaturated fatty acids, such as arachidonic acid (AA), have been shown to increase azoles susceptibility of C. albicans biofilms; however, the mechanisms are still unknown. Therefore, transcriptome analysis was conducted on biofilms exposed to sub-inhibitory concentrations of AA alone, fluconazole alone, and AA combined with fluconazole to understand the possible mechanism involved with the phenomenon. Protein ANalysis THrough Evolutionary Relationships (PANTHER) analysis from the differentially expressed genes revealed that the combination of AA and fluconazole influences biological processes associated with essential processes including methionine synthesis and those involved in ATP generation, such as AMP biosynthesis, fumarate metabolism and fatty acid oxidation. These observations suggests that the interference of AA with these processes may be a possible mechanisms to induce increased antifungal susceptibility.
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7
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Xue YP, Kao MC, Lan CY. Novel mitochondrial complex I-inhibiting peptides restrain NADH dehydrogenase activity. Sci Rep 2019; 9:13694. [PMID: 31548559 PMCID: PMC6757105 DOI: 10.1038/s41598-019-50114-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2019] [Accepted: 08/29/2019] [Indexed: 12/14/2022] Open
Abstract
The emergence of drug-resistant fungal pathogens is becoming increasingly serious due to overuse of antifungals. Antimicrobial peptides have potent activity against a broad spectrum of pathogens, including fungi, and are considered a potential new class of antifungals. In this study, we examined the activities of the newly designed peptides P-113Du and P-113Tri, together with their parental peptide P-113, against the human fungal pathogen Candida albicans. The results showed that these peptides inhibit mitochondrial complex I, specifically NADH dehydrogenase, of the electron transport chain. Moreover, P-113Du and P-113Tri also block alternative NADH dehydrogenases. Currently, most inhibitors of the mitochondrial complex I are small molecules or artificially-designed antibodies. Here, we demonstrated novel functions of antimicrobial peptides in inhibiting the mitochondrial complex I of C. albicans, providing insight in the development of new antifungal agents.
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Affiliation(s)
- Yao-Peng Xue
- Institute of Molecular and Cellular Biology, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan, ROC
| | - Mou-Chieh Kao
- Institute of Molecular Medicine, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan, ROC. .,Department of Life Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan, ROC.
| | - Chung-Yu Lan
- Institute of Molecular and Cellular Biology, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan, ROC. .,Department of Life Science, National Tsing Hua University, No. 101, Section 2, Kuang-Fu Road, Hsinchu, 30013, Taiwan, ROC.
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Abstract
Candida albicans is an opportunistic fungal pathogen of major clinical concern. The virulence of this pathogen is intimately intertwined with its metabolism. Mitochondria, which have a central metabolic role, have undergone many lineage-specific adaptations in association with their eukaryotic host. A screen for lineage-specific genes identified seven such genes specific to the CTG clade of fungi, of which C. albicans is a member. Each is required for respiratory growth and is integral to expression of complex I, III, or IV of the electron transport chain. Two genes, NUO3 and NUO4, encode supernumerary subunits of complex I, whereas NUE1 and NUE2 have nonstructural roles in expression of complex I. Similarly, the other three genes have nonstructural roles in expression of complex III (QCE1) or complex IV (COE1 and COE2). In addition to these novel additions, an alternative functional assignment was found for the mitochondrial protein encoded by MNE1 MNE1 was required for complex I expression in C. albicans, whereas the distantly related Saccharomyces cerevisiae ortholog participates in expression of complex III. Phenotypic analysis of deletion mutants showed that fermentative metabolism is unable to support optimal growth rates or yields of C. albicans However, yeast-hypha morphogenesis, an important virulence attribute, did not require respiratory metabolism under hypoxic conditions. The inability to respire also resulted in hypersensitivity to the antifungal fluconazole and in attenuated virulence in a Galleria mellonella infection model. The results show that lineage-specific adaptations have occurred in C. albicans mitochondria and highlight the significance of respiratory metabolism in the pathobiology of C. albicans IMPORTANCE Candida albicans is an opportunistic fungal pathogen of major clinical concern. The virulence of this pathogen is intimately intertwined with its metabolic behavior, and mitochondria have a central role in that metabolism. Mitochondria have undergone many evolutionary changes, which include lineage-specific adaptations in association with their eukaryotic host. Seven lineage-specific genes required for electron transport chain function were identified in the CTG clade of fungi, of which C. albicans is a member. Additionally, examination of several highly diverged orthologs encoding mitochondrial proteins demonstrated functional reassignment for one of these. Deficits imparted by deletion of these genes revealed the critical role of respiration in virulence attributes of the fungus and highlight important evolutionary adaptations in C. albicans metabolism.
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Li SX, Wu HT, Liu YT, Jiang YY, Zhang YS, Liu WD, Zhu KJ, Li DM, Zhang H. The F 1F o-ATP Synthase β Subunit Is Required for Candida albicans Pathogenicity Due to Its Role in Carbon Flexibility. Front Microbiol 2018; 9:1025. [PMID: 29875745 PMCID: PMC5974098 DOI: 10.3389/fmicb.2018.01025] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 05/01/2018] [Indexed: 11/13/2022] Open
Abstract
Previous work has explored link between mitochondrial biology and fungal pathogenicity in F1Fo-ATP synthase in Candida albicans. In this work we have detailed the more specific roles of the F1Fo-ATP synthase β subunit, a key protein subunit of F1Fo-ATP synthase. The ability to assimilate alternative carbons in glucose-limited host niches is known to be a critical factor for infection caused by opportunistic pathogens including C. albicans. The function of the F1Fo-ATP synthase β subunit was characterized through the construction of an ATP2 gene null mutant (atp2Δ/Δ) and the gene-reconstituted strain (atp2Δ/ATP2) in order to understand the link between carbon metabolism and C. albicans pathogenesis. Cell growth, viability, cellular ATP content, mitochondrial membrane potential (ΔΨm), and intracellular ROS were compared between null mutant and control strain. Results showed that growth of the atp2Δ/Δ mutant in synthetic medium was slower than in complex medium. However, the synthetic medium delayed the onset of reduced cell viability and kept cellular ATP content from becoming fully depleted. Consistent with these observations, we identified transcriptional changes in metabolic response that activated other ATP-generating pathways, thereby improving cell viability during the initial phase. Unlike glucose effects, the atp2Δ/Δ mutant exhibited an immediate and sharp reduction in cell viability on non-fermentable carbon sources, consistent with an immediate depletion of cellular ATP content. Along with a reduced viability in non-fermentable carbon sources, the atp2Δ/Δ mutant displayed avirulence in a murine model of disseminated candidiasis as well as lower fungal loads in mouse organs. Regardless of the medium, however, a decrease in mitochondrial membrane potential (ΔΨm) was found in the atp2Δ/Δ mutant but ROS levels remained in the normal range. These results suggest that the F1Fo-ATP synthase β subunit is required for C. albicans pathogenicity and operates by affecting metabolic flexibility in carbon consumption.
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Affiliation(s)
- Shui-Xiu Li
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Hao-Tian Wu
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Yu-Ting Liu
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Yi-Ying Jiang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Yi-Shan Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Wei-Da Liu
- Jiangsu Key Laboratory of Molecular Biology for Skin Diseases and STIs, Institute of Dermatology, Chinese Academy of Medical Sciences, Nanjing, China
| | - Kun-Ju Zhu
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
| | - Dong-Mei Li
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, United States
| | - Hong Zhang
- Department of Dermatology, The First Affiliated Hospital of Jinan University, Guangzhou, China.,Institute of Mycology, Jinan University, Guangzhou, China
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Krawczyk P, Jędrzejewska B, Cysewski P, Janek T. Synthesis, photophysical and biological properties of a new oxazolone fluorescent probe for bioimaging: an experimental and theoretical study. Org Biomol Chem 2018; 15:8952-8966. [PMID: 29043360 DOI: 10.1039/c7ob02439h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In this study, a new oxazolone derivative 4-{N,N-bis[2-phenyl-4-benzylidene-1,3-oxazol-5(4H)-one]amino}benzaldehyde (PB3) was synthesized and investigated as a fluorescent dye. The spectroscopic properties in different solvents were thoroughly studied. The experimental data were supported by quantum-chemical calculations using density functional theory. Measurements and theoretical calculations showed that the PB3 dye is characterized by non-monotonic solvatochromism, a strongly polar charge transfer excited state, a large Stokes' shift, a high fluorescence quantum yield and a high fluorescence lifetime. Bioconjugate complexes (PB3-concanavalin A) were studied by circular dichroism (CD) spectroscopy. The results showed that the secondary structure of concanavalin A was not significantly influenced by the PB3-fluorophore. Conventional fluorescence microscopy imaging of Candida albicans cells, incubated with the PB3-concanavalin A, was demonstrated. The results from cytochemistry experiments demonstrate that the PB3 dye has valuable advantages compared to the other long-wavelength dyes in typical fluorescence-based cell labeling applications. In vitro tolerance was evaluated by the MTT method in the human colon adenocarcinoma cell line HT29. The PB3 and bioconjugate complexes (PB3-concanavalin A), in the range of concentrations tested, were not considerably toxic. The AutoDock simulations showed LYS46 as the most likely active site for covalent bond formation during PB3-concanavalin A conjugation. In addition, theoretical studies have shown that PB3 is characterized by good bioavailability and absorption/transmission across the cell membrane. This molecule will not bioaccumulate in living organisms and should be excreted in urine without interacting with other drugs. This work provided promising results for the red fluorescent probe (PB3) as a valuable alternative to commercial probes designed for cellular labeling in biological and biomedical research.
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Affiliation(s)
- Przemysław Krawczyk
- Nicolaus Copernicus University, Collegium Medicum, Faculty of Pharmacy, Chair and Department of Physical Chemistry, Kurpińskiego 5, 85-950 Bydgoszcz, Poland.
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