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Wang WH, Lai TX, Wu YC, Chen ZT, Tseng KY, Lan CY. Associations of Rap1 with Cell Wall Integrity, Biofilm Formation, and Virulence in Candida albicans. Microbiol Spectr 2022; 10:e0328522. [PMID: 36416583 PMCID: PMC9769648 DOI: 10.1128/spectrum.03285-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 11/10/2022] [Indexed: 11/24/2022] Open
Abstract
Rap1 (repressor activator protein 1) is a multifunctional protein, playing important roles in telomeric and nontelomeric functions in many eukaryotes. Candida albicans Rap1 has been previously shown to be involved in telomeric regulation, but its other functions are still mostly unknown. In this study, we found that the deletion of the RAP1 gene altered cell wall properties, composition, and gene expression. In addition, deletion of RAP1 affected C. albicans biofilm formation and modulated phagocytosis and cytokine release by host immune cells. Finally, the RAP1 gene deletion mutant showed attenuation of C. albicans virulence in a Galleria mellonella infection model. Therefore, these findings provide new insights into Rap1 functions that are particularly relevant to pathogenesis and virulence of C. albicans. IMPORTANCE C. albicans is an important fungal pathogen of humans. The cell wall is the outermost layer of C. albicans and is important for commensalism and infection by this pathogen. Moreover, the cell wall is also an important target for antifungals. Studies of how C. albicans maintains its cell wall integrity are critical for a better understanding of fungal pathogenesis and virulence. This work focuses on exploring unknown functions of C. albicans Rap1 and reveals its contribution to cell wall integrity, biofilm formation, and virulence. Notably, these findings will also improve our general understanding of complex machinery to control pathogenesis and virulence of fungal pathogens.
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Affiliation(s)
- Wen-Han Wang
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Ting-Xiu Lai
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Yi-Chia Wu
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
| | - Zzu-Ting Chen
- Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
| | - Kuo-Yun Tseng
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
- Taiwan Mycology Reference Center, National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Zhunan Township, Miaoli County, Taiwan
| | - Chung-Yu Lan
- Institute of Molecular and Cellular Biology, National Tsing Hua University, Hsinchu, Taiwan
- Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan
- School of Medicine, National Tsing Hua University, Hsinchu, Taiwan
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The Role of Sfp1 in Candida albicans Cell Wall Maintenance. J Fungi (Basel) 2022; 8:jof8111196. [PMID: 36422017 PMCID: PMC9692975 DOI: 10.3390/jof8111196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/08/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022] Open
Abstract
The cell wall is the first interface for Candida albicans interaction with the surrounding environment and the host cells. Therefore, maintenance of cell wall integrity (CWI) is crucial for C. albicans survival and host-pathogen interaction. In response to environmental stresses, C. albicans undergoes cell wall remodeling controlled by multiple signaling pathways and transcription regulators. Here, we explored the role of the transcription factor Sfp1 in CWI. A deletion of the SFP1 gene not only caused changes in cell wall properties, cell wall composition and structure but also modulated expression of cell wall biosynthesis and remodeling genes. In addition, Cas5 is a known transcription regulator for C. albicans CWI and cell wall stress response. Interestingly, our results indicated that Sfp1 negatively controls the CAS5 gene expression by binding to its promoter element. Together, this study provides new insights into the regulation of C. albicans CWI and stress response.
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Wang X, Liu P, Jiang Y, Han B, Yan L. The prophylactic effects of monoclonal antibodies targeting the cell wall Pmt4 protein epitopes of Candida albicans in a murine model of invasive candidiasis. Front Microbiol 2022; 13:992275. [PMID: 36081783 PMCID: PMC9446456 DOI: 10.3389/fmicb.2022.992275] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 08/04/2022] [Indexed: 11/13/2022] Open
Abstract
Candida albicans (C. albicans) is the most prevalent opportunistic human pathogen, accounting for approximately half of all clinical cases of candidemia. Resistance to the existing antifungal drugs is a major challenge in clinical therapy, necessitating the development and identification of novel therapeutic agents and potential treatment strategies. Monoclonal antibody-based immunotherapy represents a promising therapeutic strategy against disseminated candidiasis. Protein mannosyltransferase (Pmt4) encodes mannosyltransferases initiating O-mannosylation of secretory proteins and is essential for cell wall composition and virulence of C. albicans. Therefore, the Pmt4 protein of C. albicans is an attractive target for the discovery of alternative antibody agents against invasive C. albicans infections. In the present study, we found that monoclonal antibodies (mAbs) C12 and C346 specifically targeted the recombinant protein mannosyltransferase 4 (rPmt4p) of C. albicans. These mAbs were produced and secreted by hybridoma cells isolated from the spleen of mice that were initially immunized with the purified rPmt4p to generate IgG antibodies. The mAbs C12 and C346 exhibited high affinity to C. albicans whole cells. Remarkably, these mAbs reduced the fungal burden, alleviated inflammation in the kidneys, and prolonged the survival rate significantly in the murine model of systemic candidiasis. Moreover, they could activate macrophage opsonophagocytic killing and neutrophil killing of C. albicans strain in vitro. These results suggested that anti-rPmt4p mAbs may provide immunotherapeutic interventions against disseminated candidiasis via opsonophagocytosis and opsonic killing activity. Our findings provide evidence for mAbs as a therapeutic option for the treatment of invasive candidiasis.
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Affiliation(s)
- Xiaojuan Wang
- School of Pharmacy, Naval Medical University, Shanghai, China
- Department of Pharmacy, Minhang Hospital, Fudan University, Shanghai, China
| | - Peng Liu
- Department of Gastroenterology, Institute for Regenerative Medicine, Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yuanying Jiang
- Department of Pharmacology, Shanghai Tenth People’s Hospital, Tongji University School of Medicine, Shanghai, China
| | - Bing Han
- Department of Pharmacy, Minhang Hospital, Fudan University, Shanghai, China
- *Correspondence: Bing Han,
| | - Lan Yan
- School of Pharmacy, Naval Medical University, Shanghai, China
- Lan Yan,
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Engineered Microbial Cell Factories for Sustainable Production of L-Lactic Acid: A Critical Review. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8060279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
With the increasing demand for the biodegradable polymer material polylactic acid and its advantage of being metabolized by the human body, L-lactic acid (L-LA) is becoming increasingly attractive in environmental protection and food industry applications. However, the supply of L-LA is not satisfied, and the price is still high. Compared to enzymatic and chemical synthesis methods, L-LA production by microbial fermentation has the advantages of low cost, large yield, simple operation, and environmental protection. This review summarizes the advances in engineering microbial cell factories to produce L-LA. First, the synthetic pathways and microorganisms for L-LA production are outlined. Then, the metabolic engineering strategies for constructing cell factories to overproduce L-LA are summarized and fermentation modes for L-LA production are also given. Finally, the challenges and prospects of the microbial production of L-LA are discussed. This review provides theoretical guidance for researchers engaged in L-LA production.
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Rao KH, Roy K, Ghosh S. Srg1, a putative protein phosphatase from the HAD-family, is involved in stress adaptation in Candida albicans. Biochim Biophys Acta Gen Subj 2022; 1866:130164. [PMID: 35523365 DOI: 10.1016/j.bbagen.2022.130164] [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: 07/11/2021] [Revised: 04/23/2022] [Accepted: 04/28/2022] [Indexed: 10/18/2022]
Abstract
BACKGROUND The cell stress response plays an important role in the survival of organisms. Studies have revealed that the pathogenic yeast Candida albicans that constantly encounters various environmental insults inside the host has emerged as an ideal system to understand the molecular mechanism (s) of stress response. In this study, we characterize a stress-inducible gene SRG1 which is a Halo Acid Dehalogenase (HAD) family member from C. albicans. METHODS We used confocal microscopy, site-directed mutagenesis, gene deletion techniques, and tandem-affinity purification and co-immunoprecipitation studies to functionally characterize SRG1. RESULTS The sub-cellular localization of Srg1 is predominantly cytoplasmic and includes punctate mitochondrial staining in the presence of salt. Protein purification studies coupled with LC-MS analysis showed that Srg1 is a phosphoprotein. The Srg1 mutant carrying S47A and S49A mutations failed to migrate to mitochondria in the presence of salt but retained its phosphatase activity. Srg1 migrates to the nucleus in ∆hog1 mutant cells indicating an unorthodox role for HAD family proteins in stress-mediated transcriptional response. Srg1 also interacts with Erg13, a component involved in the mitochondrial membrane lipid biosynthesis pathway. CONCLUSIONS A multistep relay mechanism that includes a positive modulation by the MAP kinase Hog1 and a negative modulation by the global repressor Tup1 controls SRG1 expression. GENERAL SIGNIFICANCE Taken together, our work contributes towards gaining a functional insight into a class of phosphatases that probably have evolved with novel specificities in the pathogenic yeast C. albicans to counteract stressful conditions.
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Affiliation(s)
- Kongara Hanumantha Rao
- National Institute of Plant Genome Research, Jawaharlal Nehru University Campus, New Delhi, India; Central Instrumentation Facility, Division of Research and Development, Lovely Professional University, Phagwara, Punjab, India.
| | - Kasturi Roy
- Dept. of Molecular Biology and Biotechnology, University of Kalyani., Kalyani, West Bengal, India
| | - Swagata Ghosh
- Dept. of Molecular Biology and Biotechnology, University of Kalyani., Kalyani, West Bengal, India.
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Palliyil S, Mawer M, Alawfi SA, Fogg L, Tan TH, De Cesare GB, Walker LA, MacCallum DM, Porter AJ, Munro CA. Monoclonal Antibodies Targeting Surface-Exposed Epitopes of Candida albicans Cell Wall Proteins Confer In Vivo Protection in an Infection Model. Antimicrob Agents Chemother 2022; 66:e0195721. [PMID: 35285676 PMCID: PMC9017365 DOI: 10.1128/aac.01957-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Monoclonal antibody (mAb)-based immunotherapies targeting systemic and deep-seated fungal infections are still in their early stages of development, with no licensed antifungal mAbs currently being available for patients at risk. The cell wall glycoproteins of Candida albicans are of particular interest as potential targets for therapeutic antibody generation due to their extracellular location and key involvement in fungal pathogenesis. Here, we describe the generation of recombinant human antibodies specifically targeting two key cell wall proteins (CWPs) in C. albicans: Utr2 and Pga31. These antibodies were isolated from a phage display antibody library using peptide antigens representing the surface-exposed regions of CWPs expressed at elevated levels during in vivo infection. Reformatted human-mouse chimeric mAbs preferentially recognized C. albicans hyphal forms compared to yeast cells, and increased binding was observed when the cells were grown in the presence of the antifungal agent caspofungin. In J774.1 macrophage interaction assays, mAb pretreatment resulted in the faster engulfment of C. albicans cells, suggesting a role of the CWP antibodies as opsonizing agents during phagocyte recruitment. Finally, in a series of clinically predictive mouse models of systemic candidiasis, our lead mAb achieved improved survival (83%) and a several-log reduction of the fungal burden in the kidneys, similar to the levels achieved for the fungicidal drug caspofungin and superior to the therapeutic efficacy of any anti-Candida mAb reported to date.
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Affiliation(s)
- Soumya Palliyil
- Scottish Biologics Facility, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
| | - Mark Mawer
- Scottish Biologics Facility, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
- Aberdeen Fungal Group, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
| | - Sami A. Alawfi
- Aberdeen Fungal Group, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
| | - Lily Fogg
- Scottish Biologics Facility, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
| | - Tyng H. Tan
- Scottish Biologics Facility, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
- Aberdeen Fungal Group, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
| | - Giuseppe Buda De Cesare
- Aberdeen Fungal Group, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
| | - Louise A. Walker
- Aberdeen Fungal Group, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
| | - Donna M. MacCallum
- Aberdeen Fungal Group, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
| | - Andrew J. Porter
- Scottish Biologics Facility, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
| | - Carol A. Munro
- Aberdeen Fungal Group, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeengrid.7107.1, Aberdeen, United Kingdom
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Yaakoub H, Sanchez NS, Ongay-Larios L, Courdavault V, Calenda A, Bouchara JP, Coria R, Papon N. The high osmolarity glycerol (HOG) pathway in fungi †. Crit Rev Microbiol 2021; 48:657-695. [PMID: 34893006 DOI: 10.1080/1040841x.2021.2011834] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
While fungi are widely occupying nature, many species are responsible for devastating mycosis in humans. Such niche diversity explains how quick fungal adaptation is necessary to endow the capacity of withstanding fluctuating environments and to cope with host-imposed conditions. Among all the molecular mechanisms evolved by fungi, the most studied one is the activation of the phosphorelay signalling pathways, of which the high osmolarity glycerol (HOG) pathway constitutes one of the key molecular apparatus underpinning fungal adaptation and virulence. In this review, we summarize the seminal knowledge of the HOG pathway with its more recent developments. We specifically described the HOG-mediated stress adaptation, with a particular focus on osmotic and oxidative stress, and point out some lags in our understanding of its involvement in the virulence of pathogenic species including, the medically important fungi Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus, compared to the model yeast Saccharomyces cerevisiae. Finally, we also highlighted some possible applications of the HOG pathway modifications to improve the fungal-based production of natural products in the industry.
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Affiliation(s)
- Hajar Yaakoub
- Univ Angers, Univ Brest, GEIHP, SFR ICAT, Angers, France
| | - Norma Silvia Sanchez
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Laura Ongay-Larios
- Unidad de Biología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Vincent Courdavault
- EA2106 "Biomolécules et Biotechnologies Végétales", Université de Tours, Tours, France
| | | | | | - Roberto Coria
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City, Mexico
| | - Nicolas Papon
- Univ Angers, Univ Brest, GEIHP, SFR ICAT, Angers, France
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Ibe C, Oladele RO, Alamir O. Our pursuit for effective antifungal agents targeting fungal cell wall components, where are we? Int J Antimicrob Agents 2021; 59:106477. [PMID: 34798234 DOI: 10.1016/j.ijantimicag.2021.106477] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 10/26/2021] [Accepted: 11/10/2021] [Indexed: 01/09/2023]
Abstract
Invasive mycotic infections account for an unacceptably high mortality rates in humans. These infections are initiated by the fungal cell wall which mediates host-fungi interactions. The cell wall is fused to the physiology of fungi, and it is involved in essential functions in the entire cell functionality. Components of the cell wall are synthesised and modified in the cell wall space by the activities of cell wall proteins through a range of signalling pathways that have only been described in many fungi, therefore making them suitable drug targets. The echinocandins class of cell wall-active drugs block cell wall β-1,3-glucan biosynthesis through inhibiting the catalytic subunit of the synthetic protein complex. Resistance to echinocandins can be through the acquisition of single nucleotide polymorphisms and/or through activation of cell wall signalling pathways resulting in altered cell wall proteome and elevated chitin content in the cell wall. Countering the cell wall remodelling process will enhance the effectiveness of β-1,3-glucan-active antifungal agents. Cell surface proteins are also important antifungal targets which can be used to develop rapid and robust diagnostics and more effective therapeutics. The cell wall remains a crucial target in fungi that needs to be harnessed to combat mycotic infections.
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Affiliation(s)
- Chibuike Ibe
- Department of Microbiology, Abia State University, PMB 2000 Uturu, Abia State, Nigeria.
| | - Rita O Oladele
- Medical Microbiology & Parasitology, College of Medicine, University of Lagos, Lagos State, Nigeria
| | - Omran Alamir
- Natural Sciences, College of Health Sciences, Public Authority for Applied Education and Training, Al Asimah, Kuwait
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9
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The SPFH Protein Superfamily in Fungi: Impact on Mitochondrial Function and Implications in Virulence. Microorganisms 2021; 9:microorganisms9112287. [PMID: 34835412 PMCID: PMC8624314 DOI: 10.3390/microorganisms9112287] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 10/28/2021] [Accepted: 11/01/2021] [Indexed: 11/17/2022] Open
Abstract
Integral membrane proteins from the ancient SPFH (stomatin, prohibitin, flotillin, HflK/HflC) protein superfamily are found in nearly all living organisms. Mammalian SPFH proteins are primarily associated with mitochondrial functions but also coordinate key processes such as ion transport, signaling, and mechanosensation. In addition, SPFH proteins are required for virulence in parasites. While mitochondrial functions of SPFH proteins are conserved in fungi, recent evidence has uncovered additional roles for SPFH proteins in filamentation and stress signaling. Inhibitors that target SPFH proteins have been successfully used in cancer and inflammation treatment. Thus, SPFH proteins may serve as a potential target for novel antifungal drug development. This review article surveys SPFH function in various fungal species with a special focus on the most common human fungal pathogen, Candida albicans.
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10
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Tan C, Deng JL, Zhang F, Zhu Z, Yan LJ, Zhang MJ, Yuan J, Wang SH. CWI pathway participated in vegetative growth and pathogenicity through a downstream effector AflRlm1 in Aspergillus flavus. iScience 2021; 24:103159. [PMID: 34693219 PMCID: PMC8517163 DOI: 10.1016/j.isci.2021.103159] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 08/01/2021] [Accepted: 09/17/2021] [Indexed: 11/26/2022] Open
Abstract
The cell wall is an essential dynamic structure for shielding fungus from environmental stress, and its synthesizing and remodeling are regulated by the cell wall integrity (CWI) pathway. Here, we explored the roles of a putative downstream effector AflRlm1 of CWI pathway in Aspergillus flavus. The results showed that AflRlm1 played a positive role in conidia production, sclerotium formation, aflatoxin biosynthesis, and pathogenicity. Furthermore, we provided evidence for the physical connection between AflRlm1 and AflSlt2 and determined the role of AflSlt2 in the phosphorylation of AflRlm1. Then, we discovered the importance of WSCs (cell wall integrity and stress response component) to the CWI signal and the process of AflRlm1 transferring to the nucleus after receiving the signal. Overall, this study clarified the transmission process of CWI signals and proves that the CWI pathway plays a key role in the development of A. flavus and the production of aflatoxin combined with transcriptome data analysis. Linked the CWI pathway from membrane receptors to transcription factors in A. flavus Found the phosphorylate activation and subcellular metastasis of AflRlm1 in stress Discovered the important role of AflRlm1 in aflatoxin biosynthesis
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Affiliation(s)
- Can Tan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Ji-Li Deng
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Feng Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Zhuo Zhu
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Li-Juan Yan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Meng-Juan Zhang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Jun Yuan
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shi-Hua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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11
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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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12
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Candida albicans Sfp1 Is Involved in the Cell Wall and Endoplasmic Reticulum Stress Responses Induced by Human Antimicrobial Peptide LL-37. Int J Mol Sci 2021; 22:ijms221910633. [PMID: 34638975 PMCID: PMC8508991 DOI: 10.3390/ijms221910633] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/26/2021] [Accepted: 09/28/2021] [Indexed: 12/21/2022] Open
Abstract
Candida albicans is a commensal fungus of humans but can cause infections, particularly in immunocompromised individuals, ranging from superficial to life-threatening systemic infections. The cell wall is the outermost layer of C. albicans that interacts with the host environment. Moreover, antimicrobial peptides (AMPs) are important components in innate immunity and play crucial roles in host defense. Our previous studies showed that the human AMP LL-37 binds to the cell wall of C. albicans, alters the cell wall integrity (CWI) and affects cell adhesion of this pathogen. In this study, we aimed to further investigate the molecular mechanisms underlying the C. albicans response to LL-37. We found that LL-37 causes cell wall stress, activates unfolded protein response (UPR) signaling related to the endoplasmic reticulum (ER), induces ER-derived reactive oxygen species and affects protein secretion. Interestingly, the deletion of the SFP1 gene encoding a transcription factor reduced C. albicans susceptibility to LL-37, which is cell wall-associated. Moreover, in the presence of LL-37, deletion of SFP1 attenuated the UPR pathway, upregulated oxidative stress responsive (OSR) genes and affected bovine serum albumin (BSA) degradation by secreted proteases. Therefore, these findings suggested that Sfp1 positively regulates cell wall integrity and ER homeostasis upon treatment with LL-37 and shed light on pathogen-host interactions.
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Ibe C, Munro CA. Fungal Cell Wall Proteins and Signaling Pathways Form a Cytoprotective Network to Combat Stresses. J Fungi (Basel) 2021; 7:jof7090739. [PMID: 34575777 PMCID: PMC8466366 DOI: 10.3390/jof7090739] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/01/2021] [Accepted: 09/04/2021] [Indexed: 12/13/2022] Open
Abstract
Candida species are part of the normal flora of humans, but once the immune system of the host is impaired and they escape from commensal niches, they shift from commensal to pathogen causing candidiasis. Candida albicans remains the primary cause of candidiasis, accounting for about 60% of the global candidiasis burden. The cell wall of C. albicans and related fungal pathogens forms the interface with the host, gives fungal cells their shape, and also provides protection against stresses. The cell wall is a dynamic organelle with great adaptive flexibility that allows remodeling, morphogenesis, and changes in its components in response to the environment. It is mainly composed of the inner polysaccharide rich layer (chitin, and β-glucan) and the outer protein coat (mannoproteins). The highly glycosylated protein coat mediates interactions between C. albicans cells and their environment, including reprograming of wall architecture in response to several conditions, such as carbon source, pH, high temperature, and morphogenesis. The mannoproteins are also associated with C. albicans adherence, drug resistance, and virulence. Vitally, the mannoproteins contribute to cell wall construction and especially cell wall remodeling when cells encounter physical and chemical stresses. This review describes the interconnected cell wall integrity (CWI) and stress-activated pathways (e.g., Hog1, Cek1, and Mkc1 mediated pathways) that regulates cell wall remodeling and the expression of some of the mannoproteins in C. albicans and other species. The mannoproteins of the surface coat is of great importance to pathogen survival, growth, and virulence, thus understanding their structure and function as well as regulatory mechanisms can pave the way for better management of candidiasis.
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Affiliation(s)
- Chibuike Ibe
- Department of Microbiology, Faculty of Biological Sciences, Abia State University, Uturu 441107, Nigeria
- Correspondence:
| | - Carol A. Munro
- Aberdeen Fungal Group, Institute of Medical Sciences, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Aberdeen AB24 3FX, UK;
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Antifungal efficacy of paeonol on Aspergillus flavus and its mode of action on cell walls and cell membranes. Lebensm Wiss Technol 2021. [DOI: 10.1016/j.lwt.2021.111985] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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15
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Ichikawa Y, Bruno VM, Woolford CA, Kim H, Do E, Brewer GC, Mitchell AP. Environmentally contingent control of Candida albicans cell wall integrity by transcriptional regulator Cup9. Genetics 2021; 218:iyab075. [PMID: 33989396 PMCID: PMC8864738 DOI: 10.1093/genetics/iyab075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 05/07/2021] [Indexed: 11/14/2022] Open
Abstract
The fungal pathogen Candida albicans is surrounded by a cell wall that is the target of caspofungin and other echinocandin antifungals. Candida albicans can grow in several morphological forms, notably budding yeast and hyphae. Yeast and hyphal forms differ in cell wall composition, leading us to hypothesize that there may be distinct genes required for yeast and hyphal responses to caspofungin. Mutants in 27 genes reported previously to be caspofungin hypersensitive under yeast growth conditions were all caspofungin hypersensitive under hyphal growth conditions as well. However, a screen of mutants defective in transcription factor genes revealed that Cup9 is required for normal caspofungin tolerance under hyphal and not yeast growth conditions. In a hyphal-defective efg1Δ/Δ background, Cup9 is still required for normal caspofungin tolerance. This result argues that Cup9 function is related to growth conditions rather than cell morphology. RNA-seq conducted under hyphal growth conditions indicated that 361 genes were up-regulated and 145 genes were down-regulated in response to caspofungin treatment. Both classes of caspofungin-responsive genes were enriched for cell wall-related proteins, as expected for a response to disruption of cell wall integrity and biosynthesis. The cup9Δ/Δ mutant, treated with caspofungin, had reduced RNA levels of 40 caspofungin up-regulated genes, and had increased RNA levels of 8 caspofungin down-regulated genes, an indication that Cup9 has a narrow rather than global role in the cell wall integrity response. Five Cup9-activated surface-protein genes have roles in cell wall integrity, based on mutant analysis published previously (PGA31 and IFF11) or shown here (ORF19.3499, ORF19.851, or PGA28), and therefore may explain the hypersensitivity of the cup9Δ/Δmutant to caspofungin. Our findings define Cup9 as a new determinant of caspofungin susceptibility.
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Affiliation(s)
- Yuichi Ichikawa
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Division of Cancer Biology, The Cancer Institute of JFCR, Koto-ku, Tokyo 135-8550, Japan
| | - Vincent M Bruno
- Department of Microbiology and Immunology and Institute of Genome Sciences, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Carol A Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Hannah Kim
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Institute for Genomics and Evolutionary Medicine, Temple University, Philadelphia, PA 19122, USA
| | - Eunsoo Do
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Grace C Brewer
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
| | - Aaron P Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA
- Department of Microbiology, University of Georgia, Athens, GA 30602, USA
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Qasim MN, Valle Arevalo A, Nobile CJ, Hernday AD. The Roles of Chromatin Accessibility in Regulating the Candida albicans White-Opaque Phenotypic Switch. J Fungi (Basel) 2021; 7:37. [PMID: 33435404 PMCID: PMC7826875 DOI: 10.3390/jof7010037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/05/2021] [Accepted: 01/07/2021] [Indexed: 12/18/2022] Open
Abstract
Candida albicans, a diploid polymorphic fungus, has evolved a unique heritable epigenetic program that enables reversible phenotypic switching between two cell types, referred to as "white" and "opaque". These cell types are established and maintained by distinct transcriptional programs that lead to differences in metabolic preferences, mating competencies, cellular morphologies, responses to environmental signals, interactions with the host innate immune system, and expression of approximately 20% of genes in the genome. Transcription factors (defined as sequence specific DNA-binding proteins) that regulate the establishment and heritable maintenance of the white and opaque cell types have been a primary focus of investigation in the field; however, other factors that impact chromatin accessibility, such as histone modifying enzymes, chromatin remodelers, and histone chaperone complexes, also modulate the dynamics of the white-opaque switch and have been much less studied to date. Overall, the white-opaque switch represents an attractive and relatively "simple" model system for understanding the logic and regulatory mechanisms by which heritable cell fate decisions are determined in higher eukaryotes. Here we review recent discoveries on the roles of chromatin accessibility in regulating the C. albicans white-opaque phenotypic switch.
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Affiliation(s)
- Mohammad N. Qasim
- Department of Molecular and Cell Biology, University of California-Merced, Merced, CA 95343, USA; (M.N.Q.); (A.V.A.); (C.J.N.)
- Quantitative and Systems Biology Graduate Program, University of California-Merced, Merced, CA 95343, USA
| | - Ashley Valle Arevalo
- Department of Molecular and Cell Biology, University of California-Merced, Merced, CA 95343, USA; (M.N.Q.); (A.V.A.); (C.J.N.)
- Quantitative and Systems Biology Graduate Program, University of California-Merced, Merced, CA 95343, USA
| | - Clarissa J. Nobile
- Department of Molecular and Cell Biology, University of California-Merced, Merced, CA 95343, USA; (M.N.Q.); (A.V.A.); (C.J.N.)
- Health Sciences Research Institute, University of California-Merced, Merced, CA 95343, USA
| | - Aaron D. Hernday
- Department of Molecular and Cell Biology, University of California-Merced, Merced, CA 95343, USA; (M.N.Q.); (A.V.A.); (C.J.N.)
- Health Sciences Research Institute, University of California-Merced, Merced, CA 95343, USA
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Transcriptional regulation of the caspofungin-induced cell wall damage response in Candida albicans. Curr Genet 2020; 66:1059-1068. [PMID: 32876716 DOI: 10.1007/s00294-020-01105-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 08/14/2020] [Accepted: 08/25/2020] [Indexed: 12/14/2022]
Abstract
The human fungal pathogen Candida albicans maintains pathogenic and commensal states primarily through cell wall functions. The echinocandin antifungal drug caspofungin inhibits cell wall synthesis and is widely used in treating disseminated candidiasis. Signaling pathways are critical in coordinating the adaptive response to cell wall damage (CWD). C. albicans executes a robust transcriptional program following caspofungin-induced CWD. A comprehensive analysis of signaling pathways at the transcriptional level facilitates the identification of prospective genes for functional characterization and propels the development of novel antifungal interventions. This review article focuses on the molecular functions and signaling crosstalk of the C. albicans transcription factors Sko1, Rlm1, and Cas5 in caspofungin-induced CWD signaling.
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