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Kumar D, Kumar A. Molecular Determinants Involved in Candida albicans Biofilm Formation and Regulation. Mol Biotechnol 2024; 66:1640-1659. [PMID: 37410258 DOI: 10.1007/s12033-023-00796-x] [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: 03/30/2023] [Accepted: 06/14/2023] [Indexed: 07/07/2023]
Abstract
Candida albicans is known for its pathogenicity, although it lives within the human body as a commensal member. The commensal nature of C. albicans is well controlled and regulated by the host's immune system as they live in the harmonized microenvironment. However, the development of certain unusual microhabitat conditions (change in pH, co-inhabiting microorganisms' population ratio, debilitated host-immune system) pokes this commensal fungus to transform into a pathogen in such a way that it starts to propagate very rapidly and tries to breach the epithelial barrier to enter the host's systemic circulations. In addition, Candida is infamous as a major nosocomial (hospital-acquired infection) agent because it enters the human body through venous catheters or medical prostheses. The hysterical mode of C. albicans growth builds its microcolony or biofilm, which is pathogenic for the host. Biofilms propose additional resistance mechanisms from host immunity or extracellular chemicals to aid their survival. Differential gene expressions and regulations within the biofilms cause altered morphology and metabolism. The genes associated with adhesiveness, hyphal/pseudo-hyphal growth, persister cell transformation, and biofilm formation by C. albicans are controlled by myriads of cell-signaling regulators. These genes' transcription is controlled by different molecular determinants like transcription factors and regulators. Therefore, this review has focused discussion on host-immune-sensing molecular determinants of Candida during biofilm formation, regulatory descriptors (secondary messengers, regulatory RNAs, transcription factors) of Candida involved in biofilm formation that could enable small-molecule drug discovery against these molecular determinants, and lead to disrupt the well-structured Candida biofilms effectively.
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Affiliation(s)
- Dushyant Kumar
- Department of Biotechnology, National Institute of Technology, Raipur, Chhattisgarh, 492010, India
| | - Awanish Kumar
- Department of Biotechnology, National Institute of Technology, Raipur, Chhattisgarh, 492010, India.
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2
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Henry M, Khemiri I, Tebbji F, Abu-Helu R, Vincent AT, Sellam A. Manganese homeostasis modulates fungal virulence and stress tolerance in Candida albicans. mSphere 2024; 9:e0080423. [PMID: 38380913 PMCID: PMC10964418 DOI: 10.1128/msphere.00804-23] [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: 12/21/2023] [Accepted: 01/31/2024] [Indexed: 02/22/2024] Open
Abstract
Due to the scarcity of transition metals within the human host, fungal pathogens have evolved sophisticated mechanisms to uptake and utilize these micronutrients at the infection interface. While considerable attention was turned to iron and copper acquisition mechanisms and their importance in fungal fitness, less was done regarding either the role of manganese (Mn) in infectious processes or the cellular mechanism by which fungal cells achieve their Mn-homeostasis. Here, we undertook transcriptional profiling in the pathogenic fungus Candida albicans experiencing both Mn starvation and excess to capture biological processes that are modulated by this metal. We uncovered that Mn scarcity influences diverse processes associated with fungal fitness including invasion of host cells and antifungal sensitivity. We show that Mn levels influence the abundance of iron and zinc emphasizing the complex crosstalk between metals. The deletion of SMF12, a member of Mn Nramp transporters, confirmed its contribution to Mn uptake. smf12 was unable to form hyphae and damage host cells and exhibited sensitivity to azoles. We found that the unfolded protein response (UPR), likely activated by decreased glycosylation under Mn limitation, was required to recover growth when cells were shifted from an Mn-starved to an Mn-repleted medium. RNA-seq profiling of cells exposed to Mn excess revealed that UPR was also activated. Furthermore, the UPR signaling axis Ire1-Hac1 was required to bypass Mn toxicity. Collectively, this study underscores the importance of Mn homeostasis in fungal virulence and comprehensively provides a portrait of biological functions that are modulated by Mn in a fungal pathogen. IMPORTANCE Transition metals such as manganese provide considerable functionality across biological systems as they are used as cofactors for many catalytic enzymes. The availability of manganese is very limited inside the human body. Consequently, pathogenic microbes have evolved sophisticated mechanisms to uptake this micronutrient inside the human host to sustain their growth and cause infections. Here, we undertook a comprehensive approach to understand how manganese availability impacts the biology of the prevalent fungal pathogen, Candida albicans. We uncovered that manganese homeostasis in this pathogen modulates different biological processes that are essential for host infection which underscores the value of targeting fungal manganese homeostasis for potential antifungal therapeutics development.
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Affiliation(s)
- Manon Henry
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Inès Khemiri
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
| | - Faiza Tebbji
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
| | - Rasmi Abu-Helu
- Department of Medical Laboratory Sciences, Faculty of Health Professions, Al-Quds University, Jerusalem, Palestine
| | - Antony T. Vincent
- Department of Animal Sciences, Université Laval, Quebec City, Québec, Canada
| | - Adnane Sellam
- Montreal Heart Institute/Institut de Cardiologie de Montréal, Université de Montréal, Montréal, Québec, Canada
- Department of Microbiology, Infectious Diseases and Immunology, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada
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Yan K, Guo L, Zhang B, Chang M, Meng J, Deng B, Liu J, Hou L. MAC Family Transcription Factors Enhance the Tolerance of Mycelia to Heat Stress and Promote the Primordial Formation Rate of Pleurotus ostreatus. J Fungi (Basel) 2023; 10:13. [PMID: 38248923 PMCID: PMC10816978 DOI: 10.3390/jof10010013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/05/2023] [Accepted: 12/10/2023] [Indexed: 01/23/2024] Open
Abstract
Pleurotus ostreatus is a typical tetrapolar heterologous edible mushroom, and its growth and development regulatory mechanism has become a research hotspot in recent years. The MAC1 protein is a transcription factor that perceives copper and can regulate the expression of multiple genes, thereby affecting the growth and development of organisms. However, its function in edible mushrooms is still unknown. In this study, two transcription factor genes, PoMCA1a and PoMAC1b, were identified. Afterwards, PoMAC1 overexpression (OE) and RNA interference (RNAi) strains were constructed to further explore gene function. The results showed that the PoMAC1 mutation had no significant effect on the growth rate of mycelia. Further research has shown that OE-PoMAC1a strains and RNAi-PoMAC1b strains exhibit strong tolerance under 32 °C heat stress. However, under 40 °C heat stress, the OE of PoMAC1a and PoMAC1b promoted the recovery of mycelial growth after heat stress. Second, the OE of PoMAC1a can promote the rapid formation of primordia and shorten the cultivation cycle. In summary, this study indicated that there are functional differences between PoMAC1a and PoMAC1b under different heat stresses during the vegetative growth stage, and PoMAC1a has a positive regulatory effect on the formation of primordia during the reproductive growth stage.
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Affiliation(s)
- Kexing Yan
- College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China; (K.Y.); (L.G.); (B.Z.); (M.C.); (J.M.); (B.D.)
| | - Lifeng Guo
- College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China; (K.Y.); (L.G.); (B.Z.); (M.C.); (J.M.); (B.D.)
| | - Benfeng Zhang
- College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China; (K.Y.); (L.G.); (B.Z.); (M.C.); (J.M.); (B.D.)
| | - Mingchang Chang
- College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China; (K.Y.); (L.G.); (B.Z.); (M.C.); (J.M.); (B.D.)
- Shanxi Research Center for Engineering Technology of Edible Fungi, Jinzhong 030801, China
| | - Junlong Meng
- College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China; (K.Y.); (L.G.); (B.Z.); (M.C.); (J.M.); (B.D.)
- Shanxi Research Center for Engineering Technology of Edible Fungi, Jinzhong 030801, China
| | - Bing Deng
- College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China; (K.Y.); (L.G.); (B.Z.); (M.C.); (J.M.); (B.D.)
- Shanxi Key Laboratory of Edible Fungi for Loess Plateau, Jinzhong 030801, China
| | - Jingyu Liu
- College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China; (K.Y.); (L.G.); (B.Z.); (M.C.); (J.M.); (B.D.)
- Shanxi Key Laboratory of Edible Fungi for Loess Plateau, Jinzhong 030801, China
| | - Ludan Hou
- College of Food Science and Engineering, Shanxi Agricultural University, Jinzhong 030801, China; (K.Y.); (L.G.); (B.Z.); (M.C.); (J.M.); (B.D.)
- Shanxi Key Laboratory of Edible Fungi for Loess Plateau, Jinzhong 030801, China
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Jiang Q, Deng Y, Li S, Yang D, Tao L. Sub-lethal concentrations of chlorhexidine inhibit Candida albicans growth by disrupting ROS and metal ion homeostasis. J Oral Microbiol 2023; 15:2278937. [PMID: 38415078 PMCID: PMC10898817 DOI: 10.1080/20002297.2023.2278937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 10/31/2023] [Indexed: 02/29/2024] Open
Abstract
Candida albicans is a normal resident of the human oral cavity. It is also the most common fungal pathogen, causing various oral diseases, particularly in immunocompromised individuals. Chlorhexidine digluconate (CHG) is a broad-spectrum antimicrobial agent widely used in dental practice and has been recommended to treat oral candidiasis. However, its action mechanism against the fungal pathogen C. albicans remains poorly understood. The aim of the present study was to investigate the effect of CHG at sub-lethal concentrations against C. albicans. CHG inhibited the growth of C. albicans in a dose- and time-dependent manner. Cells treated with CHG exhibited altered membrane permeability, reduced metabolic activity, and enhanced metal ion and reactive oxygen species (ROS) accumulation. Copper-sensing transcription factor Mac1, iron-sensing transcription factors Sfu1 and Sef2, and copper transporter Ctr1 regulated intracellular metal ion and ROS homeostasis in response to CHG. Deletion of MAC1, SFU1, or SEF2 increased intracellular ROS production and cell susceptibility to CHG. This study revealed a novel mechanism by which CHG induced apoptosis of C. albicans cells through the disruption of metal ion and ROS homeostasis, which may help to identify new targets for fungal infections.
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Affiliation(s)
- Qian Jiang
- College of Stomatology, Chongqing Medical University, Chongqing, China
- Department of Stomatology, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Yuchen Deng
- Department of Dermatology, Second Affiliated Hospital of Naval Medical University, Shanghai, China
| | - Shuaihu 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, China
| | - Deqin Yang
- College of Stomatology, Chongqing Medical University, Chongqing, 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, China
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Wildeman AS, Patel NK, Cormack BP, Culotta VC. The role of manganese in morphogenesis and pathogenesis of the opportunistic fungal pathogen Candida albicans. PLoS Pathog 2023; 19:e1011478. [PMID: 37363924 PMCID: PMC10328360 DOI: 10.1371/journal.ppat.1011478] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 07/07/2023] [Accepted: 06/12/2023] [Indexed: 06/28/2023] Open
Abstract
Metals such as Fe, Cu, Zn, and Mn are essential trace nutrients for all kingdoms of life, including microbial pathogens and their hosts. During infection, the mammalian host attempts to starve invading microbes of these micronutrients through responses collectively known as nutritional immunity. Nutritional immunity for Zn, Fe and Cu has been well documented for fungal infections; however Mn handling at the host-fungal pathogen interface remains largely unexplored. This work establishes the foundation of fungal resistance against Mn associated nutritional immunity through the characterization of NRAMP divalent metal transporters in the opportunistic fungal pathogen, Candida albicans. Here, we identify C. albicans Smf12 and Smf13 as two NRAMP transporters required for cellular Mn accumulation. Single or combined smf12Δ/Δ and smf13Δ/Δ mutations result in a 10-80 fold reduction in cellular Mn with an additive effect of double mutations and no losses in cellular Cu, Fe or Zn. As a result of low cellular Mn, the mutants exhibit impaired activity of mitochondrial Mn-superoxide dismutase 2 (Sod2) and cytosolic Mn-Sod3 but no defects in cytosolic Cu/Zn-Sod1 activity. Mn is also required for activity of Golgi mannosyltransferases, and smf12Δ/Δ and smf13Δ/Δ mutants show a dramatic loss in cell surface phosphomannan and in glycosylation of proteins, including an intracellular acid phosphatase and a cell wall Cu-only Sod5 that is key for oxidative stress resistance. Importantly, smf12Δ/Δ and smf13Δ/Δ mutants are defective in formation of hyphal filaments, a deficiency rescuable by supplemental Mn. In a disseminated mouse model for candidiasis where kidney is the primary target tissue, we find a marked loss in total kidney Mn during fungal invasion, implying host restriction of Mn. In this model, smf12Δ/Δ and smf13Δ/Δ C. albicans mutants displayed a significant loss in virulence. These studies establish a role for Mn in Candida pathogenesis.
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Affiliation(s)
- Asia S Wildeman
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Naisargi K Patel
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
| | - Brendan P Cormack
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Valeria C Culotta
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, United States of America
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6
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Regulatory cross-talk supports resistance to Zn intoxication in Streptococcus. PLoS Pathog 2022; 18:e1010607. [PMID: 35862444 PMCID: PMC9345489 DOI: 10.1371/journal.ppat.1010607] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 08/02/2022] [Accepted: 05/19/2022] [Indexed: 01/07/2023] Open
Abstract
Metals such as copper (Cu) and zinc (Zn) are important trace elements that can affect bacterial cell physiology but can also intoxicate bacteria at high concentrations. Discrete genetic systems for management of Cu and Zn efflux have been described in several bacterial pathogens, including streptococci. However, insight into molecular cross-talk between systems for Cu and Zn management in bacteria that drive metal detoxification, is limited. Here, we describe a biologically consequential cross-system effect of metal management in group B Streptococcus (GBS) governed by the Cu-responsive copY regulator in response to Zn. RNAseq analysis of wild-type (WT) and copY-deficient GBS subjected to metal stress revealed unique transcriptional links between the systems for Cu and Zn detoxification. We show that the Cu-sensing role of CopY extends beyond Cu and enables CopY to regulate Cu and Zn stress responses that effect changes in gene function for central cellular processes, including riboflavin synthesis. CopY also supported GBS intracellular survival in human macrophages and virulence during disseminated infection in mice. In addition, we show a novel role for CovR in modulating GBS resistance to Zn intoxication. Identification of the Zn resistome of GBS using TraDIS revealed a suite of genes essential for GBS growth in metal stress. Several of the genes identified are novel to systems that support bacterial survival in metal stress and represent a diverse set of mechanisms that underpin microbial metal homeostasis during cell stress. Overall, this study reveals a new and important mechanism of cross-system complexity driven by CopY in bacteria to regulate cellular management of metal stress and survival. Metals, such as Cu and Zn, can be used by the mammalian immune system to target bacterial pathogens for destruction, and consequently, bacteria have evolved discrete genetic systems to enable subversion of this host antimicrobial response. Systems for Cu and Zn homeostasis are well characterized, including transcriptional control elements that sense and respond to metal stress. Here, we discover novel features of metal response systems in Streptococcus, which have broad implications for bacterial pathogenesis and virulence. We show that Streptococcus resists Zn intoxication by utilizing a bona fide Cu regulator, CopY, to manage cellular metal homeostasis, and enable the bacteria to survive stressful conditions. We identify several new genes that confer resistance to Zn intoxication in Streptococcus, including some that have hitherto not been linked to metal ion homeostasis in any bacterial pathogen. Identification of a novel cross-system metal management mechanism exploited by Streptococcus to co-ordinate and achieve metal resistance enhances our understanding of metal ion homeostasis in bacteria and its effect on pathogenesis.
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7
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The Role of Glycoside Hydrolases in S. gordonii and C. albicans Interactions. Appl Environ Microbiol 2022; 88:e0011622. [PMID: 35506689 DOI: 10.1128/aem.00116-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Candida albicans can coaggregate with Streptococcus gordonii and cocolonize in the oral cavity. Saliva provides a vital microenvironment for close interactions of oral microorganisms. However, the level of fermentable carbohydrates in saliva is not sufficient to support the growth of multiple species. Glycoside hydrolases (GHs) that hydrolyze glycoproteins are critical for S. gordonii growth in low-fermentable-carbohydrate environments such as saliva. However, whether GHs are involved in the cross-kingdom interactions between C. albicans and S. gordonii under such conditions remains unknown. In this study, C. albicans and S. gordonii were cocultured in heart infusion broth with a low level of fermentable carbohydrate. Planktonic growth, biofilm formation, cell aggregation, and GH activities of monocultures and cocultures were examined. The results revealed that the planktonic growth of cocultured S. gordonii in a low-carbohydrate environment was elevated, while that of cocultured C. albicans was reduced. The biomass of S. gordonii in dual-species biofilms was higher than that of monocultures, while that of cocultured C. albicans was decreased. GH activity was observed in S. gordonii, and elevated activity of GHs was detected in S. gordonii-C. albicans cocultures, with elevated expression of GH-related genes of S. gordonii. By screening a mutant library of C. albicans, we identified a tec1Δ/Δ mutant strain that showed reduced ability to promote the growth and GH activities of S. gordonii compared with the wild-type strain. Altogether, the findings of this study demonstrate the involvement of GHs in the cross-kingdom metabolic interactions between C. albicans and S. gordonii in an environment with low level of fermentable carbohydrates. IMPORTANCE Cross-kingdom interactions between Candida albicans and oral streptococci such as Streptococcus gordonii have been reported. However, their interactions in a low-fermentable-carbohydrate environment like saliva is not clear. The current study revealed glycoside hydrolase-related cross-kingdom communications between S. gordonii and C. albicans under the low-fermentable-carbohydrate condition. We demonstrate that C. albicans can promote the growth and metabolic activities of S. gordonii by elevating the activities of cell-wall-anchored glycoside hydrolases of S. gordonii. C. albicans gene TEC1 is critical for this cross-kingdom metabolic communication.
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Singh G, Kaur JD, Pawan, Sushma, Priyanka, Satija P, Singh KN, Esteban MA, Espinosa-Ruíz C. A veratraldehyde-appended organosilicon probe and its hybrid silica nanoparticles as a dual chemosensor for colorimetric and fluorimetric detection of Cu 2+ and Fe 3+ ions. NEW J CHEM 2022. [DOI: 10.1039/d1nj05105a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Schiff bases of veratraldehyde based organosilatranes have been synthesized. The colorimetric and fluorimetric detection of 3a and its hybrid silica nanoparticles (V-NPs) revealed significant sensorial ability only towards Cu2+ and Fe3+ ions.
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Affiliation(s)
- Gurjaspreet Singh
- Department of Chemistry, Panjab University, Chandigarh 160014, India
| | - Jashan Deep Kaur
- Department of Chemistry, Panjab University, Chandigarh 160014, India
| | - Pawan
- Department of Chemistry, Panjab University, Chandigarh 160014, India
| | - Sushma
- Department of Chemistry, Panjab University, Chandigarh 160014, India
| | - Priyanka
- Department of Chemistry, Panjab University, Chandigarh 160014, India
| | - Pinky Satija
- School of Advanced Chemical Sciences, Shoolini University, Solan, Himachal Pradesh, India
| | - K. N. Singh
- Department of Chemistry, Panjab University, Chandigarh 160014, India
| | - María Angeles Esteban
- Department of Cell Biology & Histology, Faculty of Biology, University of Murcia, 30100, Murcia, Spain
| | - Cristóbal Espinosa-Ruíz
- Department of Cell Biology & Histology, Faculty of Biology, University of Murcia, 30100, Murcia, Spain
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Ceruloplasmin as a source of Cu for a fungal pathogen. J Inorg Biochem 2021; 219:111424. [PMID: 33765639 DOI: 10.1016/j.jinorgbio.2021.111424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/28/2021] [Accepted: 03/08/2021] [Indexed: 12/22/2022]
Abstract
Copper is an essential metal for virtually all organisms, yet little is known about the extracellular sources of this micronutrient. In serum, the most abundant extracellular Cu-binding molecule is the multi‑copper oxidase ceruloplasmin (Cp). Cp levels increase during infection and inflammation, and pathogens can be exposed to high Cp at sites of infection. It is not known whether Cp might serve as a Cu source for microbial pathogens and we tested this using the opportunistic fungal pathogen Candida albicans. We find that C. albicans can use whole serum as a Cu source and that this Cu is sensed by the transcription factor protein Mac1. Mac1 activates expression of Mn-SOD3 superoxide dismutase and represses Cu/Zn-SOD1 during Cu starvation and both responses are regulated by serum Cu. We also show that purified human Cp can act as a sole source of Cu for the fungus and likewise modulates the Mac1 Cu stress response. To investigate whether Cp is a Cu source in serum, we compared the ability of C. albicans to use serum from wild type versus Cp-/- mutant mice. We find that serum lacking Cp is deficient in its ability to trigger the Mac1 Cu response. C. albicans did accumulate Cu from Cp-/- serum, but this Cu was not efficiently sensed by Mac1. We conclude that Cp and non-Cp Cu sources are not equivalent and are handled differently by the fungal cell. Overall, these studies are the first to show that Cp is a preferred source of Cu for a pathogen.
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Smith AD, Garcia-Santamarina S, Ralle M, Loiselle DR, Haystead TA, Thiele DJ. Transcription factor-driven alternative localization of Cryptococcus neoformans superoxide dismutase. J Biol Chem 2021; 296:100391. [PMID: 33567338 PMCID: PMC7961099 DOI: 10.1016/j.jbc.2021.100391] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/29/2021] [Accepted: 02/04/2021] [Indexed: 12/16/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen whose pathogenic lifestyle is linked to its ability to cope with fluctuating levels of copper (Cu), an essential metal involved in multiple virulence mechanisms, within distinct host niches. During lethal cryptococcal meningitis in the brain, C. neoformans senses a Cu-deficient environment and is highly dependent on its ability to scavenge trace levels of Cu from its host and adapt to Cu scarcity to successfully colonize this niche. In this study, we demonstrate for this critical adaptation, the Cu-sensing transcription factor Cuf1 differentially regulates the expression of the SOD1 and SOD2 superoxide dismutases in novel ways. Genetic and transcriptional analysis reveals Cuf1 specifies 5’-truncations of the SOD1 and SOD2 mRNAs through specific binding to Cu responsive elements within their respective promoter regions. This results in Cuf1-dependent repression of the highly abundant SOD1 and simultaneously induces expression of two isoforms of SOD2, the canonical mitochondrial targeted isoform and a novel alternative cytosolic isoform, from a single alternative transcript produced specifically under Cu limitation. The generation of cytosolic Sod2 during Cu limitation is required to maintain cellular antioxidant defense against superoxide stress both in vitro and in vivo. Further, decoupling Cuf1 regulation of Sod2 localization compromises the ability of C. neoformans to colonize organs in murine models of cryptococcosis. Our results provide a link between transcription factor–mediated alteration of protein localization and cell proliferation under stress, which could impact tissue colonization by a fungal pathogen.
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Affiliation(s)
- Aaron D Smith
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
| | | | - Martina Ralle
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon, USA
| | - David R Loiselle
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
| | - Timothy A Haystead
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
| | - Dennis J Thiele
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA; Department of Biochemistry, Duke University, Durham, North Carolina, USA; Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA.
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