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Anand JP, Moore SC, Dixon EE, Perrien Naccarato CM, West JL, Delong LJ, Burgess E, Twarozynski JJ, Traynor JR. Structure-Activity Relationships of the Fentanyl Scaffold: Identification of Antagonists as Potential Opioid Overdose Reversal Agents. ACS Chem Neurosci 2024; 15:2830-2841. [PMID: 38994846 DOI: 10.1021/acschemneuro.4c00203] [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] [Indexed: 07/13/2024] Open
Abstract
Opioid-related overdoses account for almost half of all drug overdose deaths in the United States and cause more preventable deaths every year than car crashes. Fentanyl, a highly potent mu opioid receptor (MOR) agonist and its analogues (fentalogues) are increasingly found in illicit drug samples, both where the primary drug of abuse is an opioid and where it is not. The prevalence of fentalogues in the illicit drug market is thought to be the primary driver of the increased number of opioid-related overdose deaths since 2016. In fact, fentanyl and its analogues are involved in more than 70% of opioid-related overdoses. The standard opioid overdose rescue therapy naloxone is often insufficient to reverse opioid overdoses caused by fentalogue agonists under current treatment paradigms. However, the pharmacology of many fentalogues is unknown. Moreover, within the fentalogue series of compounds, it is possible that antagonists could be identified that might be superior to naloxone as opioid overdose reversal agents. In this report, we explore the pharmacology of 70 fentalogues and identify compounds that behave as MOR antagonists in vitro and demonstrate with one of these reversals of fentanyl-induced respiratory depression in the mouse. Such compounds could provide leads for the development of effective agents for the reversal of opioid overdose.
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Affiliation(s)
- Jessica P Anand
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Edward F. Domino Research Center, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Sierra C Moore
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Emma E Dixon
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Joshua L West
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Edward F. Domino Research Center, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Lennon J Delong
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Emily Burgess
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Edward F. Domino Research Center, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Jack J Twarozynski
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - John R Traynor
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109, United States
- Edward F. Domino Research Center, University of Michigan, Ann Arbor, Michigan 48109, United States
- Department of Medicinal Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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2
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Guzmán A, Rosales-Torres AM, Medina-Moctezuma ZB, González-Aretia D, Hernández-Coronado CG. Effects and action mechanism of gonadotropins on ovarian follicular cells: A novel role of Sphingosine-1-Phosphate (S1P). A review. Gen Comp Endocrinol 2024; 357:114593. [PMID: 39047797 DOI: 10.1016/j.ygcen.2024.114593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 07/02/2024] [Accepted: 07/19/2024] [Indexed: 07/27/2024]
Abstract
Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) control antral follicular growth by regulating several processes, such as the synthesis of hormones and signaling molecules, proliferation, survival, apoptosis, luteinization, and ovulation. To exert these effects, gonadotropins bind to their respective Gs protein-coupled receptors, activating the protein kinase A (PKA) pathway or recruiting Gq proteins to activate protein kinase C (PKC) signaling. Although the action mechanism of FSH and LH is clear, recently, it has been shown that both gonadotropins promote the synthesis of sphingosine-1-phosphate (S1P) in granulosa and theca cells through the activation of sphingosine kinase 1. Moreover, the inhibition of SPHKs reduces S1P synthesis, cell viability, and the proliferation of follicular cells in response to gonadotropins, and the addition of S1P to the culture medium increases the proliferation of granulosa and theca cells without apparent effects on sexual steroid synthesis. Therefore, we consider that S1P is a crucial signaling molecule that complements the canonical gonadotropin pathway to promote the proliferation and viability of granulosa and theca cells.
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Affiliation(s)
- A Guzmán
- Universidad Autónoma Metropolitana Unidad Xochimilco, Departamento Producción Agrícola y Animal, Ciudad de México, Mexico
| | - A M Rosales-Torres
- Universidad Autónoma Metropolitana Unidad Xochimilco, Departamento Producción Agrícola y Animal, Ciudad de México, Mexico
| | - Z B Medina-Moctezuma
- Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Ciudad de México, Mexico
| | - D González-Aretia
- Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Ciudad de México, Mexico
| | - C G Hernández-Coronado
- Universidad Autónoma Metropolitana Unidad Xochimilco, Departamento Producción Agrícola y Animal, Ciudad de México, Mexico.
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3
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Kang YS, Jung J, Brown H, Mateusiak C, Doering TL, Brent MR. How host-like signals drive gene expression and capsule expansion in Cryptococcus neoformans. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.04.19.537239. [PMID: 37131703 PMCID: PMC10153387 DOI: 10.1101/2023.04.19.537239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen with a polysaccharide capsule that becomes greatly enlarged in the mammalian host and during in vitro growth under host-like conditions. To understand how individual environmental signals affect capsule size and gene expression, we grew cells in all combinations of five signals implicated in capsule size and systematically measured cell and capsule sizes. We also sampled these cultures over time and performed RNA-Seq in quadruplicate, yielding 881 RNA-Seq samples. Analysis of the resulting data sets showed that capsule induction in tissue culture medium, typically used to represent host-like conditions, requires the presence of either CO2 or exogenous cyclic AMP (cAMP). Surprisingly, adding either of these pushes overall gene expression in the opposite direction from tissue culture media alone, even though both are required for capsule development. Another unexpected finding was that rich medium blocks capsule growth completely. Statistical analysis further revealed many genes whose expression is associated with capsule thickness; deletion of one of these significantly reduced capsule size. Beyond illuminating capsule induction, our massive, uniformly collected dataset will be a significant resource for the research community.
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Affiliation(s)
- Yu Sung Kang
- These authors contributed equally
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
| | - Jeffery Jung
- These authors contributed equally
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
| | - Holly Brown
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
| | - Chase Mateusiak
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
| | - Tamara L. Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110
| | - Michael R. Brent
- Center for Genome Sciences and Systems Biology, Washington University School of Medicine, St. Louis, MO 63110
- Department of Computer Science and Engineering, Washington University, St. Louis, MO 63108
- Department of Genetics, Washington University School of Medicine, St. Louis, MO 63110
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4
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Chan PL, Kwan HS, Xie Y, Wong KH, Chang J. Transcriptome Analysis Reveals Mycelial and Fruiting Responses to Lithium Chloride in Coprinopsis cinerea. J Fungi (Basel) 2024; 10:140. [PMID: 38392812 PMCID: PMC10890143 DOI: 10.3390/jof10020140] [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: 01/11/2024] [Revised: 02/02/2024] [Accepted: 02/07/2024] [Indexed: 02/24/2024] Open
Abstract
Lithium chloride (LiCl) has been used in signalling and molecular studies of animals, plants, and yeast. However, information on its roles in basidiomycetous fungi is still limited. In this study, we used RNA-Seq to study the effects of LiCl on Coprinopsis cinerea. LiCl enhanced mycelial growth and inhibited fruiting body formation in C. cinerea. RNA-Seq of the LiCl-treated C. cinerea resulted in a total of 14,128 genes. There were 1199 differentially expressed genes (DEGs) between the LiCl-treated samples and control samples in the mycelium stage (the first time point), and 1391 DEGs were detected when the control samples were forming hyphal knots while the treated samples were still in the mycelium (the second time point). Pathway enrichment analysis of the DEGs revealed a significant association between enhanced mycelium growth in the LiCl-treated C. cinerea and metabolic pathways. In addition, the DEGs involved in cellular process pathways, including "cell cycle-yeast" and "meiosis-yeast", were identified in suppressed C. cinerea fruiting body formation by LiCl under favourable environmental conditions. As LiCl can predominantly inhibit the activity of glycogen synthase kinase3 (GSK3), our findings suggest that LiCl affects the expression of genes involved in fruiting body initiation and cellular processes by inhibiting GSK3 activity which is essential for fruiting body formation.
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Affiliation(s)
- Po-Lam Chan
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Hoi-Shan Kwan
- Food Research Centre, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Yichun Xie
- Food Research Centre, School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
- State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Ka-Hing Wong
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong SAR, China
- Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Jinhui Chang
- Research Institute for Future Food, The Hong Kong Polytechnic University, Hong Kong SAR, China
- Department of Food Science and Nutrition, The Hong Kong Polytechnic University, Hong Kong SAR, China
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5
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Hilbert ZA, Bednarek JM, Schwiesow MJW, Chung KY, Moreau CT, Brown JCS, Elde NC. Distinct pathways of adaptive evolution in Cryptococcus neoformans reveal a mutation in adenylyl cyclase with trade-offs for pathogenicity. Curr Biol 2023; 33:4136-4149.e9. [PMID: 37708888 PMCID: PMC10592076 DOI: 10.1016/j.cub.2023.08.054] [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: 04/06/2023] [Revised: 07/13/2023] [Accepted: 08/17/2023] [Indexed: 09/16/2023]
Abstract
Pathogenic fungi populate a wide range of environments and infect a diversity of host species. Despite this substantial biological flexibility, the impact of interactions between fungi and their hosts on the evolution of pathogenicity remains unclear. We studied how repeated interactions between the fungus Cryptococcus neoformans and relevant environmental and mammalian host cells-amoeba and mouse macrophages-shape the evolution of this model fungal pathogen. First, using a collection of clinical and environmental isolates of C. neoformans, we characterized a range of survival phenotypes for these strains when exposed to host cells of different species. We then performed serial passages of an environmentally isolated C. neoformans strain through either amoeba or macrophages for ∼75 generations to observe how these interactions select for improved replication within hosts. In one adapted population, we identified a single point mutation in the adenylyl cyclase gene, CAC1, that swept to fixation and confers a strong competitive advantage for growth inside macrophages. Strikingly, this growth advantage in macrophages is inversely correlated with disease severity during mouse infections, suggesting that adaptation to specific host niches can markedly reduce the pathogenicity of these fungi. These results raise intriguing questions about the influence of cyclic AMP (cAMP) signaling on pathogenicity and highlight the role of seemingly small adaptive changes in promoting fundamental shifts in the intracellular behavior and virulence of these important human pathogens.
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Affiliation(s)
- Zoë A Hilbert
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA; Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
| | - Joseph M Bednarek
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Mara J W Schwiesow
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA; Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Krystal Y Chung
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Christian T Moreau
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Jessica C S Brown
- School of Biological Sciences, University of Utah, Salt Lake City, UT 84112, USA
| | - Nels C Elde
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112, USA; Howard Hughes Medical Institute, University of Utah School of Medicine, Salt Lake City, UT 84112, USA.
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6
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TORC1 Signaling in Fungi: From Yeasts to Filamentous Fungi. Microorganisms 2023; 11:microorganisms11010218. [PMID: 36677510 PMCID: PMC9864104 DOI: 10.3390/microorganisms11010218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 01/18/2023] Open
Abstract
Target of rapamycin complex 1 (TORC1) is an important regulator of various signaling pathways. It can control cell growth and development by integrating multiple signals from amino acids, glucose, phosphate, growth factors, pressure, oxidation, and so on. In recent years, it has been reported that TORC1 is of great significance in regulating cytotoxicity, morphology, protein synthesis and degradation, nutrient absorption, and metabolism. In this review, we mainly discuss the upstream and downstream signaling pathways of TORC1 to reveal its role in fungi.
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7
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Li L, Zhu XM, Zhang YR, Cai YY, Wang JY, Liu MY, Wang JY, Bao JD, Lin FC. Research on the Molecular Interaction Mechanism between Plants and Pathogenic Fungi. Int J Mol Sci 2022; 23:ijms23094658. [PMID: 35563048 PMCID: PMC9104627 DOI: 10.3390/ijms23094658] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/07/2022] [Accepted: 04/21/2022] [Indexed: 02/01/2023] Open
Abstract
Plant diseases caused by fungi are one of the major threats to global food security and understanding the interactions between fungi and plants is of great significance for plant disease control. The interaction between pathogenic fungi and plants is a complex process. From the perspective of pathogenic fungi, pathogenic fungi are involved in the regulation of pathogenicity by surface signal recognition proteins, MAPK signaling pathways, transcription factors, and pathogenic factors in the process of infecting plants. From the perspective of plant immunity, the signal pathway of immune response, the signal transduction pathway that induces plant immunity, and the function of plant cytoskeleton are the keys to studying plant resistance. In this review, we summarize the current research progress of fungi–plant interactions from multiple aspects and discuss the prospects and challenges of phytopathogenic fungi and their host interactions.
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Affiliation(s)
- Lin Li
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (L.L.); (X.-M.Z.); (J.-Y.W.); (J.-D.B.)
| | - Xue-Ming Zhu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (L.L.); (X.-M.Z.); (J.-Y.W.); (J.-D.B.)
| | - Yun-Ran Zhang
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Y.-R.Z.); (Y.-Y.C.); (J.-Y.W.); (M.-Y.L.)
| | - Ying-Ying Cai
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Y.-R.Z.); (Y.-Y.C.); (J.-Y.W.); (M.-Y.L.)
| | - Jing-Yi Wang
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Y.-R.Z.); (Y.-Y.C.); (J.-Y.W.); (M.-Y.L.)
| | - Meng-Yu Liu
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Y.-R.Z.); (Y.-Y.C.); (J.-Y.W.); (M.-Y.L.)
| | - Jiao-Yu Wang
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (L.L.); (X.-M.Z.); (J.-Y.W.); (J.-D.B.)
| | - Jian-Dong Bao
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (L.L.); (X.-M.Z.); (J.-Y.W.); (J.-D.B.)
| | - Fu-Cheng Lin
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China; (L.L.); (X.-M.Z.); (J.-Y.W.); (J.-D.B.)
- State Key Laboratory for Managing Biotic and Chemical Treats to the Quality and Safety of Agro-Products, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; (Y.-R.Z.); (Y.-Y.C.); (J.-Y.W.); (M.-Y.L.)
- Correspondence: ; Tel.: +86-571-88404007
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8
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Adenylyl Cyclase and Protein Kinase A Play Redundant and Distinct Roles in Growth, Differentiation, Antifungal Drug Resistance, and Pathogenicity of Candida auris. mBio 2021; 12:e0272921. [PMID: 34663094 PMCID: PMC8524339 DOI: 10.1128/mbio.02729-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Candida auris is a globally emerging multidrug-resistant fungal pathogen. Its pathogenicity-related signaling networks are largely unknown. Here, we characterized the pathobiological functions of the cyclic AMP (cAMP)/protein kinase A (PKA) signaling pathway in C. auris. We focused on adenylyl cyclase (CYR1), the PKA regulatory subunit (BCY1), and the PKA catalytic subunits (TPK1 and TPK2). We concluded that PKA acts both dependently and independently of Cyr1 in C. auris. Tpk1 and Tpk2 have major and minor roles, respectively, in PKA activity and functions. Both Cyr1 and PKA promote growth, thermotolerance, filamentous growth, and resistance to stress and antifungal drugs by regulating expression of multiple effector genes. In addition, Cyr1 and PKA subunits were involved in disinfectant resistance of C. auris. However, deletion of both TPK1 and TPK2 generally resulted in more severe defects than CYR1 deletion, indicating that Cyr1 and PKA play redundant and distinct roles. Notably, Tpk1 and Tpk2 have redundant but Cyr1-independent roles in haploid-to-diploid cell transition, which increases virulence of C. auris. However, Tpk1 and Tpk2 often play opposing roles in formation of biofilms and the cell wall components chitin and chitosan. Surprisingly, deletion of CYR1 or TPK1/TPK2, which resulted in severe in vitro growth defects at 37°C, did not attenuate virulence, and BCY1 deletion reduced virulence of C. auris in a systemic murine infection model. In conclusion, this study provides comprehensive insights into the role of the cAMP/PKA pathway in drug resistance and pathogenicity of C. auris and suggests a potential therapeutic option for treatment of C. auris-mediated candidemia.
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9
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Investigation of Antifungal Mechanisms of Thymol in the Human Fungal Pathogen, Cryptococcus neoformans. Molecules 2021; 26:molecules26113476. [PMID: 34200464 PMCID: PMC8201179 DOI: 10.3390/molecules26113476] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/03/2021] [Accepted: 06/03/2021] [Indexed: 11/17/2022] Open
Abstract
Due to lifespan extension and changes in global climate, the increase in mycoses caused by primary and opportunistic fungal pathogens is now a global concern. Despite increasing attention, limited options are available for the treatment of systematic and invasive mycoses, owing to the evolutionary similarity between humans and fungi. Although plants produce a diversity of chemicals to protect themselves from pathogens, the molecular targets and modes of action of these plant-derived chemicals have not been well characterized. Using a reverse genetics approach, the present study revealed that thymol, a monoterpene alcohol from Thymus vulgaris L., (Lamiaceae), exhibits antifungal activity against Cryptococcus neoformans by regulating multiple signaling pathways including calcineurin, unfolded protein response, and HOG (high-osmolarity glycerol) MAPK (mitogen-activated protein kinase) pathways. Thymol treatment reduced the intracellular concentration of Ca2+ by controlling the expression levels of calcium transporter genes in a calcineurin-dependent manner. We demonstrated that thymol decreased N-glycosylation by regulating the expression levels of genes involved in glycan-mediated post-translational modifications. Furthermore, thymol treatment reduced endogenous ergosterol content by decreasing the expression of ergosterol biosynthesis genes in a HOG MAPK pathway-dependent manner. Collectively, this study sheds light on the antifungal mechanisms of thymol against C. neoformans.
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10
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The Transcription Factor Pdr802 Regulates Titan Cell Formation and Pathogenicity of Cryptococcus neoformans. mBio 2021; 12:mBio.03457-20. [PMID: 33688010 PMCID: PMC8092302 DOI: 10.1128/mbio.03457-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The pathogenic yeast Cryptococcus neoformans presents a worldwide threat to human health, especially in the context of immunocompromise, and current antifungal therapy is hindered by cost, limited availability, and inadequate efficacy. After the infectious particle is inhaled, C. neoformans initiates a complex transcriptional program that integrates cellular responses and enables adaptation to the host lung environment. Cryptococcus neoformans is a ubiquitous, opportunistic fungal pathogen that kills almost 200,000 people worldwide each year. It is acquired when mammalian hosts inhale the infectious propagules; these are deposited in the lung and, in the context of immunocompromise, may disseminate to the brain and cause lethal meningoencephalitis. Once inside the host, C. neoformans undergoes a variety of adaptive processes, including secretion of virulence factors, expansion of a polysaccharide capsule that impedes phagocytosis, and the production of giant (Titan) cells. The transcription factor Pdr802 is one regulator of these responses to the host environment. Expression of the corresponding gene is highly induced under host-like conditions in vitro and is critical for C. neoformans dissemination and virulence in a mouse model of infection. Direct targets of Pdr802 include the quorum sensing proteins Pqp1, Opt1, and Liv3; the transcription factors Stb4, Zfc3, and Bzp4, which regulate cryptococcal brain infectivity and capsule thickness; the calcineurin targets Had1 and Crz1, important for cell wall remodeling and C. neoformans virulence; and additional genes related to resistance to host temperature and oxidative stress, and to urease activity. Notably, cryptococci engineered to lack Pdr802 showed a dramatic increase in Titan cells, which are not phagocytosed and have diminished ability to directly cross biological barriers. This explains the limited dissemination of pdr802 mutant cells to the central nervous system and the consequently reduced virulence of this strain. The role of Pdr802 as a negative regulator of Titan cell formation is thus critical for cryptococcal pathogenicity.
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11
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Roth C, Murray D, Scott A, Fu C, Averette AF, Sun S, Heitman J, Magwene PM. Pleiotropy and epistasis within and between signaling pathways defines the genetic architecture of fungal virulence. PLoS Genet 2021; 17:e1009313. [PMID: 33493169 PMCID: PMC7861560 DOI: 10.1371/journal.pgen.1009313] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 02/04/2021] [Accepted: 12/17/2020] [Indexed: 01/11/2023] Open
Abstract
Cryptococcal disease is estimated to affect nearly a quarter of a million people annually. Environmental isolates of Cryptococcus deneoformans, which make up 15 to 30% of clinical infections in temperate climates such as Europe, vary in their pathogenicity, ranging from benign to hyper-virulent. Key traits that contribute to virulence, such as the production of the pigment melanin, an extracellular polysaccharide capsule, and the ability to grow at human body temperature have been identified, yet little is known about the genetic basis of variation in such traits. Here we investigate the genetic basis of melanization, capsule size, thermal tolerance, oxidative stress resistance, and antifungal drug sensitivity using quantitative trait locus (QTL) mapping in progeny derived from a cross between two divergent C. deneoformans strains. Using a "function-valued" QTL analysis framework that exploits both time-series information and growth differences across multiple environments, we identified QTL for each of these virulence traits and drug susceptibility. For three QTL we identified the underlying genes and nucleotide differences that govern variation in virulence traits. One of these genes, RIC8, which encodes a regulator of cAMP-PKA signaling, contributes to variation in four virulence traits: melanization, capsule size, thermal tolerance, and resistance to oxidative stress. Two major effect QTL for amphotericin B resistance map to the genes SSK1 and SSK2, which encode key components of the HOG pathway, a fungal-specific signal transduction network that orchestrates cellular responses to osmotic and other stresses. We also discovered complex epistatic interactions within and between genes in the HOG and cAMP-PKA pathways that regulate antifungal drug resistance and resistance to oxidative stress. Our findings advance the understanding of virulence traits among diverse lineages of Cryptococcus, and highlight the role of genetic variation in key stress-responsive signaling pathways as a major contributor to phenotypic variation.
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Affiliation(s)
- Cullen Roth
- Department of Biology, Duke University, Durham, North Carolina, United States of America
- University Program in Genetics and Genomics, Duke University, Durham, North Carolina, United States of America
| | - Debra Murray
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Alexandria Scott
- Department of Biology, Duke University, Durham, North Carolina, United States of America
| | - Ci Fu
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Anna F. Averette
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Paul M. Magwene
- Department of Biology, Duke University, Durham, North Carolina, United States of America
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12
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Zhang M, Li Y, Wang T, Bi Y, Li R, Huang Y, Mao R, Jiang Q, Liu Y, Prusky DB. AaPKAc Regulates Differentiation of Infection Structures Induced by Physicochemical Signals From Pear Fruit Cuticular Wax, Secondary Metabolism, and Pathogenicity of Alternaria alternata. FRONTIERS IN PLANT SCIENCE 2021; 12:642601. [PMID: 33968101 PMCID: PMC8096925 DOI: 10.3389/fpls.2021.642601] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/16/2021] [Indexed: 05/03/2023]
Abstract
Alternaria alternata, the casual agent of black rot of pear fruit, can sense and respond to the physicochemical cues from the host surface and form infection structures during infection. To evaluate the role of cyclic AMP-dependent protein kinase (cAMP-PKA) signaling in surface sensing of A. alternata, we isolated and functionally characterized the cyclic adenosine monophosphate-dependent protein kinase A catalytic subunit gene (AaPKAc). Gene expression results showed that AaPKAc was strongly expressed during the early stages of appressorium formation on hydrophobic surfaces. Knockout mutants ΔAaPKAc were generated by replacing the target genes via homologous recombination events. We found that intracellular cAMP content increased but PKA content decreased in ΔAaPKAc mutant strain. Appressorium formation and infection hyphae were reduced in the ΔAaPKAc mutant strain, and the ability of the ΔAaPKAc mutant strain to recognize and respond to high hydrophobicity surfaces and different surface waxes was lower than in the wild type (WT) strain. In comparison with the WT strain, the appressorium formation rate of the ΔAaPKAc mutant strain on high hydrophobicity and fruit wax extract surface was reduced by 31.6 and 49.3% 4 h after incubation, respectively. In addition, AaPKAc is required for the hypha growth, biomass, pathogenicity, and toxin production of A. alternata. However, AaPKAc negatively regulated conidia formation, melanin production, and osmotic stress resistance. Collectively, AaPKAc is required for pre-penetration, developmental, physiological, and pathological processes in A. alternata.
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Affiliation(s)
- Miao Zhang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Yongcai Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
- *Correspondence: Yongcai Li,
| | - Tiaolan Wang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Yang Bi
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Rong Li
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Yi Huang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Renyan Mao
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Qianqian Jiang
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Yongxiang Liu
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
| | - Dov B. Prusky
- College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, China
- Department of Postharvest Science of Fresh Produce, Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
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13
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Perlatti B, Harris G, Nichols CB, Ekanayake DI, Alspaugh JA, Gloer JB, Bills GF. Campafungins: Inhibitors of Candida albicans and Cryptococcus neoformans Hyphal Growth. JOURNAL OF NATURAL PRODUCTS 2020; 83:2718-2726. [PMID: 32881504 PMCID: PMC7530089 DOI: 10.1021/acs.jnatprod.0c00641] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Campafungin A is a polyketide that was recognized in the Candida albicans fitness test due to its antiproliferative and antihyphal activity. Its mode of action was hypothesized to involve inhibition of a cAMP-dependent PKA pathway. The originally proposed structure appeared to require a polyketide assembled in a somewhat unusual fashion. However, structural characterization data were never formally published. This background stimulated a reinvestigation in which campafungin A and three closely related minor constituents were purified from fermentations of a strain of the ascomycete fungus Plenodomus enteroleucus. Labeling studies, along with extensive NMR analysis, enabled assignment of a revised structure consistent with conventional polyketide synthetic machinery. The structure elucidation of campafungin A and new analogues encountered in this study, designated here as campafungins B, C, and D, is presented, along with a proposed biosynthetic route. The antimicrobial spectrum was expanded to methicillin-resistant Staphylococcus aureus, Candida tropicalis, Candida glabrata, Cryptococcus neoformans, Aspergillus fumigatus, and Schizosaccharomyces pombe, with MICs ranging as low as 4-8 μg mL-1 in C. neoformans. Mode-of-action studies employing libraries of C. neoformans mutants indicated that multiple pathways were affected, but mutants in PKA/cAMP pathways were unaffected, indicating that the mode of action was distinct from that observed in C. albicans.
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Affiliation(s)
- Bruno Perlatti
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77054, United States
| | - Guy Harris
- Guy Harris Consulting, 464 Fairview Road, Belington, West Virginia 26250, United States
| | - Connie B Nichols
- Departments of Medicine and Molecular Genetics & Microbiology, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Dulamini I Ekanayake
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - J Andrew Alspaugh
- Departments of Medicine and Molecular Genetics & Microbiology, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - James B Gloer
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, United States
| | - Gerald F Bills
- Texas Therapeutics Institute, The Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas 77054, United States
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14
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Genome-wide functional analysis of phosphatases in the pathogenic fungus Cryptococcus neoformans. Nat Commun 2020; 11:4212. [PMID: 32839469 PMCID: PMC7445287 DOI: 10.1038/s41467-020-18028-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 07/30/2020] [Indexed: 12/13/2022] Open
Abstract
Phosphatases, together with kinases and transcription factors, are key components in cellular signalling networks. Here, we present a systematic functional analysis of the phosphatases in Cryptococcus neoformans, a fungal pathogen that causes life-threatening fungal meningoencephalitis. We analyse 230 signature-tagged mutant strains for 114 putative phosphatases under 30 distinct in vitro growth conditions, revealing at least one function for 60 of these proteins. Large-scale virulence and infectivity assays using insect and mouse models indicate roles in pathogenicity for 31 phosphatases involved in various processes such as thermotolerance, melanin and capsule production, stress responses, O-mannosylation, or retromer function. Notably, phosphatases Xpp1, Ssu72, Siw14, and Sit4 promote blood-brain barrier adhesion and crossing by C. neoformans. Together with our previous systematic studies of transcription factors and kinases, our results provide comprehensive insight into the pathobiological signalling circuitry of C. neoformans. Phosphatases are key components in cellular signalling networks. Here, the authors present a systematic functional analysis of phosphatases of the fungal pathogen Cryptococcus neoformans, revealing roles in virulence, stress responses, O-mannosylation, retromer function and other processes.
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15
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Fungal kinases and transcription factors regulating brain infection in Cryptococcus neoformans. Nat Commun 2020; 11:1521. [PMID: 32251295 PMCID: PMC7090016 DOI: 10.1038/s41467-020-15329-2] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 03/03/2020] [Indexed: 12/19/2022] Open
Abstract
Cryptococcus neoformans causes fatal fungal meningoencephalitis. Here, we study the roles played by fungal kinases and transcription factors (TFs) in blood-brain barrier (BBB) crossing and brain infection in mice. We use a brain infectivity assay to screen signature-tagged mutagenesis (STM)-based libraries of mutants defective in kinases and TFs, generated in the C. neoformans H99 strain. We also monitor in vivo transcription profiles of kinases and TFs during host infection using NanoString technology. These analyses identify signalling components involved in BBB adhesion and crossing, or survival in the brain parenchyma. The TFs Pdr802, Hob1, and Sre1 are required for infection under all the conditions tested here. Hob1 controls the expression of several factors involved in brain infection, including inositol transporters, a metalloprotease, PDR802, and SRE1. However, Hob1 is dispensable for most cellular functions in Cryptococcus deuterogattii R265, a strain that does not target the brain during infection. Our results indicate that Hob1 is a master regulator of brain infectivity in C. neoformans. Cryptococcus neoformans causes fatal fungal meningoencephalitis. Here, the authors identify fungal kinases and transcription factors involved in blood-brain barrier crossing and brain infection in mice.
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16
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Matsumoto Y, Azami S, Shiga H, Nagamachi T, Moriyama H, Yamashita Y, Yoshikawa A, Sugita T. Induction of signal transduction pathways related to the pathogenicity of Cryptococcus neoformans in the host environment. Drug Discov Ther 2020; 13:177-182. [PMID: 31534068 DOI: 10.5582/ddt.2019.01047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Cryptococcus neoformans, a human pathogenic fungus, infects immunocompromised humans and causes serious diseases such as cerebral meningitis. C. neoformans controls the expression of virulence factors in response to the host environment via various signal transduction pathways. Understanding the molecular mechanisms involved in C. neoformans infection will contribute to the development of methods to prevent and treat C. neoformans-related diseases. C. neoformans produces virulence factors, such as a polysaccharide capsule and melanin, to escape host immunity. Several proteins of C. neoformans are reported to regulate production of the virulence factors. In this review, on the basis of studies using gene-deficient mutants of C. neoformans and animal infection models, we outline the signal transduction pathways involved in the regulation of virulence factors.
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Affiliation(s)
| | - Saki Azami
- Department of Microbiology, Meiji Pharmaceutical University
| | - Haruka Shiga
- Department of Microbiology, Meiji Pharmaceutical University
| | - Tae Nagamachi
- Department of Microbiology, Meiji Pharmaceutical University
| | | | - Yuki Yamashita
- Department of Microbiology, Meiji Pharmaceutical University
| | | | - Takashi Sugita
- Department of Microbiology, Meiji Pharmaceutical University
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17
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Maliehe M, Ntoi MA, Lahiri S, Folorunso OS, Ogundeji AO, Pohl CH, Sebolai OM. Environmental Factors That Contribute to the Maintenance of Cryptococcus neoformans Pathogenesis. Microorganisms 2020; 8:microorganisms8020180. [PMID: 32012843 PMCID: PMC7074686 DOI: 10.3390/microorganisms8020180] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/04/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023] Open
Abstract
The ability of microorganisms to colonise and display an intracellular lifestyle within a host body increases their fitness to survive and avoid extinction. This host–pathogen association drives microbial evolution, as such organisms are under selective pressure and can become more pathogenic. Some of these microorganisms can quickly spread through the environment via transmission. The non-transmittable fungal pathogens, such as Cryptococcus, probably return into the environment upon decomposition of the infected host. This review analyses whether re-entry of the pathogen into the environment causes restoration of its non-pathogenic state or whether environmental factors and parameters assist them in maintaining pathogenesis. Cryptococcus (C.) neoformans is therefore used as a model organism to evaluate the impact of environmental stress factors that aid the survival and pathogenesis of C. neoformans intracellularly and extracellularly.
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18
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Caza M, Kronstad JW. The cAMP/Protein Kinase a Pathway Regulates Virulence and Adaptation to Host Conditions in Cryptococcus neoformans. Front Cell Infect Microbiol 2019; 9:212. [PMID: 31275865 PMCID: PMC6592070 DOI: 10.3389/fcimb.2019.00212] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 05/31/2019] [Indexed: 12/28/2022] Open
Abstract
Nutrient sensing is critical for adaptation of fungi to environmental and host conditions. The conserved cAMP/PKA signaling pathway contributes to adaptation by sensing the availability of key nutrients such as glucose and directing changes in gene expression and metabolism. Interestingly, the cAMP/PKA pathway in fungal pathogens also influences the expression of virulence determinants in response to nutritional and host signals. For instance, protein kinase A (PKA) in the human pathogen Cryptococcus neoformans plays a central role in orchestrating phenotypic changes, such as capsule elaboration and melanin production, that directly impact disease development. In this review, we focus first on insights into the role of the cAMP/PKA pathway in nutrient sensing for the model yeast Saccharomyces cerevisiae to provide a foundation for understanding the pathway in C. neoformans. We then discuss key features of cAMP/PKA signaling in C. neoformans including new insights emerging from the analysis of transcriptional and proteomic changes in strains with altered PKA activity and expression. Finally, we highlight recent studies that connect the cAMP/PKA pathway to cell surface remodeling and the formation of titan cells.
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Affiliation(s)
- Mélissa Caza
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - James W Kronstad
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
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19
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CO 2 Signaling through the Ptc2-Ssn3 Axis Governs Sustained Hyphal Development of Candida albicans by Reducing Ume6 Phosphorylation and Degradation. mBio 2019; 10:mBio.02320-18. [PMID: 30647154 PMCID: PMC6336421 DOI: 10.1128/mbio.02320-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Candida albicans is the most common cause of invasive fungal infections in humans. Its ability to sense and adapt to changing carbon dioxide levels is crucial for its pathogenesis. Carbon dioxide promotes hyphal development. The hypha-specific transcription factor Ume6 is rapidly degraded in air, but is stable under physiological CO2 and hypoxia to sustain hyphal elongation. Here, we show that Ume6 stability is regulated by two parallel E3 ubiquitin ligases, SCFGrr1 and Ubr1, in response to CO2 and O2, respectively. To uncover the CO2 signaling pathway that regulates Ume6 stability, we performed genetic screens for mutants unable to respond to CO2 for sustained filamentation. We find that the type 2C protein phosphatase Ptc2 is specifically required for CO2-induced stabilization of Ume6 and hyphal elongation. In contrast, the cyclin-dependent kinase Ssn3 is found to be required for Ume6 phosphorylation and degradation in atmospheric CO2 Furthermore, we find that Ssn3 is dephosphorylated in 5% CO2 in a Ptc2-dependent manner, whereas deletion of PTC2 has no effect on Ssn3 phosphorylation in air. Our study uncovers the Ptc2-Ssn3 axis as a new CO2 signaling pathway that controls hyphal elongation by regulating Ume6 stability in C. albicans IMPORTANCE The capacity to sense and adapt to changing carbon dioxide levels is crucial for all organisms. In fungi, CO2 is a key determinant involved in fundamental biological processes, including growth, morphology, and virulence. In the pathogenic fungus Candida albicans, high CO2 is directly sensed by adenylyl cyclase to promote hyphal growth. However, little is known about the mechanism by which hyphal development is maintained in response to physiological levels of CO2 Here we report that a signal transduction system mediated by a phosphatase-kinase pair controls CO2-responsive Ume6 phosphorylation and stability that in turn dictate hyphal elongation. Our results unravel a new regulatory mechanism of CO2 signaling in fungi.
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20
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Rahim K, Huo L, Li C, Zhang P, Basit A, Xiang B, Ting B, Hao X, Zhu X. Identification of a basidiomycete-specific Vilse-like GTPase activating proteins (GAPs) and its roles in the production of virulence factors in Cryptococcus neoformans. FEMS Yeast Res 2019; 17:4644832. [PMID: 29177429 DOI: 10.1093/femsyr/fox089] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2017] [Accepted: 11/20/2017] [Indexed: 12/25/2022] Open
Abstract
Cryptococcus neoformans is a basidiomycetous pathogenic yeast that causes fatal infections in both immunocompetent and immunocompromised patients. Regulation on the production of its virulence factors is not fully understood. Here we reported the characterization of a gene, named CVH1(CNA06260), encoding a Drosophila Vilse-like RhoGAP homolog, which is hallmarked by three conserved functional domains: WW, MyTH4 and RhoGAP. Phylogenetic analysis suggests that CVH1 is highly conserved from protists to mammals and interestingly in basidiomycetes, but absent in plants or Ascomycota and other lower fungi. This phylogenetic distribution indicates an evolutionary link among these groups of organisms. Functional analyses demonstrated that CVH1 was involved in stress tolerance and virulence factor production. By disrupting CVH1, we created a second mutant cvh1Δ with the CRISPR-Cas9 editing tool. The mutant strain exhibited hypersensitivity to osmotic stress by 2 M sorbitol and NaCl, suggesting defects in the HOG signaling pathway and an interaction of Cvh1 with the HOG pathway. Hypersensitivity of cvh1Δ to 1% Congo red and 0.01% SDS suggests that the cell wall integrity was impaired in the mutant. And cvh1Δ hardly produced the pigment melanin and capsule. Our study for the first time demonstrates that the fungal Vilse-like RhoGAP CVH1 is an important regulator of multiple biological processes in C. neoformans, and provides novel insights into the regulatory circuit of stress resistance/cell wall integrity, and laccase and capsule synthesis in C. neoformans.
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Affiliation(s)
- Kashif Rahim
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Liang Huo
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Chenxi Li
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Ping Zhang
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Abdul Basit
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Biyun Xiang
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Bie Ting
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Xiaoran Hao
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
| | - Xudong Zhu
- Beijing Key Laboratory of Genetic Engineering Drug and Biotechnology, Institute of Biochemistry and Biotechnology, College of Life Sciences, Beijing Normal University, Beijing 100875, China
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21
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Transcriptional Profiling of Patient Isolates Identifies a Novel TOR/Starvation Regulatory Pathway in Cryptococcal Virulence. mBio 2018; 9:mBio.02353-18. [PMID: 30563896 PMCID: PMC6299223 DOI: 10.1128/mbio.02353-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Human infection with Cryptococcus causes up to a quarter of a million AIDS-related deaths annually and is the most common cause of nonviral meningitis in the United States. As an opportunistic fungal pathogen, Cryptococcus neoformans is distinguished by its ability to adapt to diverse host environments, including plants, amoebae, and mammals. In the present study, comparative transcriptomics of the fungus within human cerebrospinal fluid identified expression profiles representative of low-nutrient adaptive responses. Transcriptomics of fungal isolates from a cohort of HIV/AIDS patients identified high expression levels of an alternative carbon nutrient transporter gene, STL1, to be associated with poor early fungicidal activity, an important clinical prognostic marker. Mouse modeling and pathway analysis demonstrated a role for STL1 in mammalian pathogenesis and revealed that STL1 expression is regulated by a novel multigene regulatory mechanism involving the CAC2 subunit of the chromatin assembly complex 1, CAF-1. In this pathway, the global regulator of virulence gene VAD1 was found to transcriptionally regulate a cryptococcal homolog of a cytosolic protein, Ecm15, in turn required for nuclear transport of the Cac2 protein. Derepression of STL1 by the CAC2-containing CAF-1 complex was mediated by Cac2 and modulated binding and suppression of the STL1 enhancer element. Derepression of STL1 resulted in enhanced survival and growth of the fungus in the presence of low-nutrient, alternative carbon sources, facilitating virulence in mice. This study underscores the utility of ex vivo expression profiling of fungal clinical isolates and provides fundamental genetic understanding of saprophyte adaption to the human host.IMPORTANCE Cryptococcus is a fungal pathogen that kills an estimated quarter of a million individuals yearly and is the most common cause of nonviral meningitis in the United States. The fungus is carried in about 10% of the adult population and, after reactivation, causes disease in a wide variety of immunosuppressed individuals, including the HIV infected and patients receiving transplant conditioning, cancer therapy, or corticosteroid therapy for autoimmune diseases. The fungus is widely carried in the soil but can also cause infections in plants and mammals. However, the mechanisms for this widespread ability to infect a variety of hosts are poorly understood. The present study identified adaptation to low nutrients as a key property that allows the fungus to inhabit these diverse environments. Further studies identified a nutrient transporter gene, STL1, to be upregulated under low nutrients and to be associated with early fungicidal activity, a marker of poor clinical outcome in a cohort of HIV/AIDS patients. Understanding molecular mechanisms involved in adaptation to the human host may help to design better methods of control and treatment of widely dispersed fungal pathogens such as Cryptococcus.
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Zhou X, Ballou ER. The Cryptococcus neoformans Titan Cell: From In Vivo Phenomenon to In Vitro Model. CURRENT CLINICAL MICROBIOLOGY REPORTS 2018. [DOI: 10.1007/s40588-018-0107-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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23
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Sestari SJ, Brito WA, Neves BJ, Soares CMA, Salem-Izacc SM. Inhibition of protein kinase A affects Paracoccidioides lutzii dimorphism. Int J Biol Macromol 2018. [PMID: 29518446 DOI: 10.1016/j.ijbiomac.2018.03.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A critical step in the lifecycle of many fungal pathogens is the ability to switch between filamentous and yeast growth, a process known as dimorphism. cAMP-dependent protein kinase (PKA) controls morphological changes and the pathogenicity of several animal and plant pathogenic fungi. In this work, we report the analysis of PKA activity during the mycelium to yeast transition in the pathogenic fungus Paracoccidioides lutzii. This fungus, as well as the closely related species Paracoccidioides brasiliensis, causes paracoccidioidomycosis, a systemic mycosis that affects thousands of people in Latin America. Infection occurs when hypha fragments or spores released from mycelium are inhaled by the host, an event that triggers the morphological switch. We show here that PKA activity is regulated in the fungus phase, increasing during the mycelium to yeast transition. Also, morphological transition from mycelium to yeast is blocked by the compound H89, a specific PKA inhibitor. Nevertheless, the fungus recovers its ability to change morphology when H89 is removed from the culture media. This recovery is accompanied by a significant increase in PKA activity. Our results strongly indicate that PKA directly affects phase transition in P. lutzii.
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Affiliation(s)
- Sheila J Sestari
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Brazil
| | - Wesley A Brito
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Brazil; Unidade Universitária de Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás, Brazil; Centro Universitário de Anápolis, UniEvangélica, Brazil
| | - Bruno J Neves
- Centro Universitário de Anápolis, UniEvangélica, Brazil
| | - Celia M A Soares
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Brazil
| | - Silvia M Salem-Izacc
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Brazil.
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24
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Trevijano-Contador N, de Oliveira HC, García-Rodas R, Rossi SA, Llorente I, Zaballos Á, Janbon G, Ariño J, Zaragoza Ó. Cryptococcus neoformans can form titan-like cells in vitro in response to multiple signals. PLoS Pathog 2018; 14:e1007007. [PMID: 29775477 PMCID: PMC5959073 DOI: 10.1371/journal.ppat.1007007] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 04/03/2018] [Indexed: 02/07/2023] Open
Abstract
Cryptococcus neoformans is an encapsulated pathogenic yeast that can change the size of the cells during infection. In particular, this process can occur by enlarging the size of the capsule without modifying the size of the cell body, or by increasing the diameter of the cell body, which is normally accompanied by an increase of the capsule too. This last process leads to the formation of cells of an abnormal enlarged size denominated titan cells. Previous works characterized titan cell formation during pulmonary infection but research on this topic has been hampered due to the difficulty to obtain them in vitro. In this work, we describe in vitro conditions (low nutrient, serum supplemented medium at neutral pH) that promote the transition from regular to titan-like cells. Moreover, addition of azide and static incubation of the cultures in a CO2 enriched atmosphere favored cellular enlargement. This transition occurred at low cell densities, suggesting that the process was regulated by quorum sensing molecules and it was independent of the cryptococcal serotype/species. Transition to titan-like cell was impaired by pharmacological inhibition of PKC signaling pathway. Analysis of the gene expression profile during the transition to titan-like cells showed overexpression of enzymes involved in carbohydrate metabolism, as well as proteins from the coatomer complex, and related to iron metabolism. Indeed, we observed that iron limitation also induced the formation of titan cells. Our gene expression analysis also revealed other elements involved in titan cell formation, such as calnexin, whose absence resulted in appearance of abnormal large cells even in regular rich media. In summary, our work provides a new alternative method to investigate titan cell formation devoid the bioethical problems that involve animal experimentation. Cryptococcus neoformans is a fungal pathogen that has a significant incidence in HIV+ patients in particular, in Sub-saharan Africa, Asia and South America. This yeast poses an excellent model to investigate fungal virulence because it develops many strategies to adapt to the host and evade the immune response. One of the adaptation mechanisms involves the formation of Titan Cells, which are yeast of an abnormal large size. However, research on these cells has been limited to in vivo studies (mainly in mice) because they were not reproducibly found in vitro. In this work, we describe several conditions that induce the appearance of cells that mimic titan cells, and that we denominated as titan-like cells. The main factor that induced titan-like cells was the addition of serum to nutrient limited media. This has allowed to easily performing new approaches to characterize several signaling pathways involved in their development. We found that the formation of these cells is regulated by quorum sensing molecules, and that pathways such as cAMP and PKC regulate the process of cellular enlargement. We have also performed transcriptomic analysis, which led to the identification of new genes that could be involved in the process. This work will open different research lines that will contribute to the elucidation of the role of these cells during infection and on the development of cryptococcal disease.
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Affiliation(s)
- Nuria Trevijano-Contador
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Haroldo Cesar de Oliveira
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
- Universidade Estadual Paulista (UNESP), Faculdade de Ciências Farmacêuticas, Câmpus Araraquara, Departamento de Análises Clínicas, Laboratório de Micologia Clínica, Araraquara, São Paulo, Brazil
| | - Rocío García-Rodas
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Suélen Andreia Rossi
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Irene Llorente
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Ángel Zaballos
- Genomics Unit, Core Scientific Services, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Guilhem Janbon
- Institut Pasteur, Unité Biologie des ARN des Pathogènes Fongiques, Département de Mycologie, Paris, France
| | - Joaquín Ariño
- Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
| | - Óscar Zaragoza
- Mycology Reference Laboratory, National Centre for Microbiology, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
- * E-mail:
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25
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Dambuza IM, Drake T, Chapuis A, Zhou X, Correia J, Taylor-Smith L, LeGrave N, Rasmussen T, Fisher MC, Bicanic T, Harrison TS, Jaspars M, May RC, Brown GD, Yuecel R, MacCallum DM, Ballou ER. The Cryptococcus neoformans Titan cell is an inducible and regulated morphotype underlying pathogenesis. PLoS Pathog 2018; 14:e1006978. [PMID: 29775474 PMCID: PMC5959070 DOI: 10.1371/journal.ppat.1006978] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 03/16/2018] [Indexed: 02/06/2023] Open
Abstract
Fungal cells change shape in response to environmental stimuli, and these morphogenic transitions drive pathogenesis and niche adaptation. For example, dimorphic fungi switch between yeast and hyphae in response to changing temperature. The basidiomycete Cryptococcus neoformans undergoes an unusual morphogenetic transition in the host lung from haploid yeast to large, highly polyploid cells termed Titan cells. Titan cells influence fungal interaction with host cells, including through increased drug resistance, altered cell size, and altered Pathogen Associated Molecular Pattern exposure. Despite the important role these cells play in pathogenesis, understanding the environmental stimuli that drive the morphological transition, and the molecular mechanisms underlying their unique biology, has been hampered by the lack of a reproducible in vitro induction system. Here we demonstrate reproducible in vitro Titan cell induction in response to environmental stimuli consistent with the host lung. In vitro Titan cells exhibit all the properties of in vivo generated Titan cells, the current gold standard, including altered capsule, cell wall, size, high mother cell ploidy, and aneuploid progeny. We identify the bacterial peptidoglycan subunit Muramyl Dipeptide as a serum compound associated with shift in cell size and ploidy, and demonstrate the capacity of bronchial lavage fluid and bacterial co-culture to induce Titanisation. Additionally, we demonstrate the capacity of our assay to identify established (cAMP/PKA) and previously undescribed (USV101) regulators of Titanisation in vitro. Finally, we investigate the Titanisation capacity of clinical isolates and their impact on disease outcome. Together, these findings provide new insight into the environmental stimuli and molecular mechanisms underlying the yeast-to-Titan transition and establish an essential in vitro model for the future characterization of this important morphotype.
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Affiliation(s)
- Ivy M. Dambuza
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Thomas Drake
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Ambre Chapuis
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Xin Zhou
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Joao Correia
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Leanne Taylor-Smith
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Nathalie LeGrave
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Aberdeen, United Kingdom
- Francis Crick Institute, London, United Kingdom
| | - Tim Rasmussen
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Aberdeen, United Kingdom
- Institut für Biochemie, Universität Würzburg, Wurzburg, Germany
| | - Matthew C. Fisher
- Dpt. Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Tihana Bicanic
- Institute of Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Thomas S. Harrison
- Institute of Infection and Immunity, St George’s University of London, London, United Kingdom
| | - Marcel Jaspars
- Marine Biodiscovery Centre, Department of Chemistry, University of Aberdeen, Aberdeen, United Kingdom
| | - Robin C. May
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
| | - Gordon D. Brown
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Raif Yuecel
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Donna M. MacCallum
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Elizabeth R. Ballou
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, United Kingdom
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26
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Liu Y, Yang K, Qin Q, Lin G, Hu T, Xu Z, Wang S. G Protein α Subunit GpaB is Required for Asexual Development, Aflatoxin Biosynthesis and Pathogenicity by Regulating cAMP Signaling in Aspergillus flavus. Toxins (Basel) 2018. [PMID: 29534423 PMCID: PMC5869405 DOI: 10.3390/toxins10030117] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The heterotrimeric G proteins are critical for signal transduction and function in numerous biological processes including vegetative growth, asexual development and fungal virulence in fungi. Here, we identified four G protein alpha subunits (GanA, GpaB, FadA and GaoC) in the notorious Aflatoxin-producing fungus Aspergillus flavus. GanA, GpaB and FadA have homologues in other fungal species, while GaoC is a novel one. Here, we showed that the loss function of gpaB displayed a defect in conidiophore formation and considerably reduced expression levels of conidia-specific genes brlA and abaA. A decreased viability of cell wall integrity stress and oxidative stress were also found in the ∆gpaB mutant. More importantly, aflatoxin (AF) biosynthesis and infection on crop seeds were severely impaired in the gpaB-deficient mutant. Further analyses demonstrated that the intracellular cAMP levels significantly reduced in the gpaB-deficient mutant compared to wildtype strains. Additionally, an alteration of PKA activities in the ∆gpaB mutant was also found. Overall, our results indicated that GpaB played diverse roles in asexual sporulation, AF biosynthesis and virulence by regulating cAMP signaling in Aspergillus flavus.
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Affiliation(s)
- Yinghang Liu
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Kunlong Yang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Qiuping Qin
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
- Xiamen Anjie Medical Data Technology Co. Ltd., Xiamen 361115, China.
| | - Guinan Lin
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Tianran Hu
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Zhangling Xu
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Shihua Wang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, 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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27
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Abstract
Cryptococcus neoformans is a human pathogenic yeast that causes hundreds of thousands of deaths worldwide among susceptible individuals, in particular, HIV+ patients. This yeast has developed several adaptation mechanisms that allow replication within the host. During decades, this yeast has been well known for a very peculiar and unique structure that contributes to virulence, a complex polysaccharide capsule that surrounds the cell wall. In contrast to other fungal pathogens, such as Candida albicans or Aspergillus fumigatus, the role of morphological transitions has not been studied in the virulence of Cryptococcus neoformans since this yeast does not form hyphae during infection. However, in the last years, different groups have described the ability of this fungus to change its size during infection. In particular, Cryptococcus can form "titan cells," which are blastoconidia of an abnormal large size. Since their discovery, there is increasing evidence that these cells contribute, not only to long-term persistence in the host, but they can also actively participate in the development of the disease. Recently, several groups have simultaneously described different media that induce the appearance of titan cells in laboratory conditions. Using these conditions, new inducing factors and signaling pathways involved in this transition have been described. In this article, we will review the main phenotypic features of these cells, factors, and transduction pathways that induce cell growth, and how titan cells contribute to the disease caused by this pathogen.
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28
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Song Y, Laureijssen-van de Sande WWJ, Moreno LF, Gerrits van den Ende B, Li R, de Hoog S. Comparative Ecology of Capsular Exophiala Species Causing Disseminated Infection in Humans. Front Microbiol 2017; 8:2514. [PMID: 29312215 PMCID: PMC5742258 DOI: 10.3389/fmicb.2017.02514] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/04/2017] [Indexed: 12/15/2022] Open
Abstract
Exophiala spinifera and Exophiala dermatitidis (Fungi: Chaetothyriales) are black yeast agents potentially causing disseminated infection in apparently healthy humans. They are the only Exophiala species producing extracellular polysaccharides around yeast cells. In order to gain understanding of eventual differences in intrinsic virulence of the species, their clinical profiles were compared and found to be different, suggesting pathogenic strategies rather than coincidental opportunism. Ecologically relevant factors were compared in a model set of strains of both species, and significant differences were found in clinical and environmental preferences, but virulence, tested in Galleria mellonella larvae, yielded nearly identical results. Virulence factors, i.e., melanin, capsule and muriform cells responded in opposite direction under hydrogen peroxide and temperature stress and thus were inconsistent with their hypothesized role in survival of phagocytosis. On the basis of physiological profiles, possible natural habitats of both species were extrapolated, which proved to be environmental rather than animal-associated. Using comparative genomic analyses we found differences in gene content related to lipid metabolism, cell wall modification and polysaccharide capsule production. Despite the fact that both species cause disseminated infections in apparently healthy humans, it is concluded that they are opportunists rather than pathogens.
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Affiliation(s)
- Yinggai Song
- Department of Dermatology, Peking University First Hospital, Beijing, China.,Research Center for Medical Mycology, Peking University, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis of Dermatoses, Peking University First Hospital, Beijing, China.,Westerdijk Fungal Biodiversity Institute, Utrecht, Netherlands
| | | | | | | | - Ruoyu Li
- Department of Dermatology, Peking University First Hospital, Beijing, China.,Research Center for Medical Mycology, Peking University, Beijing, China.,Beijing Key Laboratory of Molecular Diagnosis of Dermatoses, Peking University First Hospital, Beijing, China
| | - Sybren de Hoog
- Westerdijk Fungal Biodiversity Institute, Utrecht, Netherlands.,Center of Expertise in Mycology Radboudumc/CWZ, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
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29
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Bruni GO, Battle B, Kelly B, Zhang Z, Wang P. Comparative proteomic analysis of Gib2 validating its adaptor function in Cryptococcus neoformans. PLoS One 2017; 12:e0180243. [PMID: 28686685 PMCID: PMC5501510 DOI: 10.1371/journal.pone.0180243] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 06/12/2017] [Indexed: 01/09/2023] Open
Abstract
Cryptococcus neoformans causes often-fatal fungal meningoencephalitis in immunocompromised individuals. While the exact disease mechanisms remain elusive, signal transduction pathways mediated by key elements such as G-protein α subunit Gpa1, small GTPase Ras1, and atypical Gβ-like/RACK1 protein Gib2 are known to play important roles in C. neoformans virulence. Gib2 is important for normal growth, differentiation, and pathogenicity, and it also positively regulates cAMP levels in conjunction with Gpa1. Interestingly, Gib2 displays a scaffold protein property by interacting with a wide variety of cellular proteins. To explore Gib2 global regulatory functions, we performed two-dimensional differential gel electrophoresis (DIGE) analysis and found that GIB2 disruption results in an increased expression of 304 protein spots (43.4%) and a decreased expression of 396 protein spots (56.6%). Analysis of 96 proteins whose expression changes were deemed significant (≥ +/- 1.5- fold) revealed that 75 proteins belong to at least 12 functional protein groups. Among them, eight groups have the statistical stringency of p ≤ 0.05, and four groups, including Hsp70/71 heat shock protein homologs and ribosomal proteins, survived the Bonferroni correction. This finding is consistent with earlier established roles for the human Gβ-like/RACK1 and the budding yeast Saccharomyces cerevisiae Asc1. It suggests that Gib2 could also be part of the complex affecting ribosomal biogenesis and protein translation in C. neoformans. Since eukaryotic Hsp70/71 proteins are involved in the facilitation of nascent protein folding, processing, and protection of cells against stress, we also propose that Gib2-regulated stress responses are linked to fungal virulence. Collectively, our study supports a conserved role of Gβ-like/RACK/Gib2 proteins in the essential cellular process of ribosomal biogenesis and protein translation. Our study also highlights a multifaceted regulatory role of Gib2 in the growth and pathogenicity of C. neoformans.
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Affiliation(s)
- Gillian O Bruni
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Blake Battle
- College of Arts and Sciences, Loyola University New Orleans, New Orleans, LA, United States of America
| | - Ben Kelly
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
| | - Zhengguang Zhang
- Department of Plant Pathology, College of Plant Protection, Nanjing Agricultural University, Nanjing, China
| | - Ping Wang
- Department of Microbiology, Immunology, and Parasitology, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America.,Department of Pediatrics, Louisiana State University Health Sciences Center, New Orleans, LA, United States of America
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30
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Song N, Dai Q, Zhu B, Wu Y, Xu M, Voegele RT, Gao X, Kang Z, Huang L. Gα proteins Gvm2 and Gvm3 regulate vegetative growth, asexual development, and pathogenicityon apple in Valsa mali. PLoS One 2017; 12:e0173141. [PMID: 28267786 PMCID: PMC5340391 DOI: 10.1371/journal.pone.0173141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 02/15/2017] [Indexed: 11/22/2022] Open
Abstract
In fungi, heterotrimeric guanine-nucleotide binding proteins (G-proteins) are key elements of signal transduction pathways, which control growth, asexual and sexual development, as well as virulence. In this study, we have identified two genes encoding heterotrimeric G protein alpha subunits, named Gvm2 and Gvm3, from Valsa mali, the causal agent of apple Valsa canker. Characterization of Gvm2 and Gvm3 mutants indicates that Gvm3 may be a crucial regulator of vegetative growth. Deletion of the corresponding gene results in a 20% reduction in growth rate. Besides, Gvm2 and Gvm3 seem to be involved in asexual reproduction, and mutants are hypersensitive to oxidative and cell membrane stresses. Interestingly, both G protein alpha subunits were most probably involved in V. mali virulence. In infection assays using Malus domestica cv. ‘Fuji’ leaves and twigs, the size of lesions caused by deletion mutants △Gvm2, or △Gvm3 are significantly reduced. Furthermore, many genes encoding hydrolytic enzymes—important virulence factors in V. mali—are expressed at a lower level in these deletion mutants. Our results suggest that Gvm2 and Gvm3 play an important role in virulence probably by regulation of expression of cell wall degrading enzymes. △Gvm2, and △Gvm3 mutants were further analyzed with respect to their impact on the transcript levels of genes in the cAMP/PKA pathway. The expression of the genes encoding adenylate cyclase VmAC, protein kinase A (PKA) regulatory subunit VmPKR, and PKA catalytic subunit VmPKA1 are down-regulated in both mutants. Further analyses indicated that intracellular cAMP level and PKA activity are down-regulated in the △Gvm3 mutant, but are basically unchanged in the △Gvm2 mutant. Overall, our findings indicate that both Gvm2 and Gvm3 play diverse roles in the modulation of vegetative growth, asexual development, and virulence in V. mali.
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Affiliation(s)
- Na Song
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People’s Republic of China
| | - Qingqing Dai
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People’s Republic of China
| | - Baitao Zhu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People’s Republic of China
| | - Yuxing Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People’s Republic of China
| | - Ming Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People’s Republic of China
| | - Ralf Thomas Voegele
- Fachgebiet Phytopathologie, Institut für Phytomedizin, Universitӓt Hohenheim, Stuttgart, Germany
| | - Xiaoning Gao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People’s Republic of China
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People’s Republic of China
| | - Lili Huang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, People’s Republic of China
- * E-mail:
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31
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Abstract
Adaptation to alternating CO2 concentrations is crucial for all organisms. Carbonic anhydrases—metalloenzymes that have been found in all domains of life—enable fixation of scarce CO2 by accelerating its conversion to bicarbonate and ensure maintenance of cellular metabolism. In fungi and other eukaryotes, the carbonic anhydrase Nce103 has been shown to be essential for growth in air (~0.04% CO2). Expression of NCE103 is regulated in response to CO2 availability. In Saccharomyces cerevisiae, NCE103 is activated by the transcription factor ScCst6, and in Candida albicans and Candida glabrata, it is activated by its homologues CaRca1 and CgRca1, respectively. To identify the kinase controlling Cst6/Rca1, we screened an S. cerevisiae kinase/phosphatase mutant library for the ability to regulate NCE103 in a CO2-dependent manner. We identified ScSch9 as a potential ScCst6-specific kinase, as the sch9Δ mutant strain showed deregulated NCE103 expression on the RNA and protein levels. Immunoprecipitation revealed the binding capabilities of both proteins, and detection of ScCst6 phosphorylation by ScSch9 in vitro confirmed Sch9 as the Cst6 kinase. We could show that CO2-dependent activation of Sch9, which is part of a kinase cascade, is mediated by lipid/Pkh1/2 signaling but not TORC1. Finally, we tested conservation of the identified regulatory cascade in the pathogenic yeast species C. albicans and C. glabrata. Deletion of SCH9 homologues of both species impaired CO2-dependent regulation of NCE103 expression, which indicates a conservation of the CO2 adaptation mechanism among yeasts. Thus, Sch9 is a Cst6/Rca1 kinase that links CO2 adaptation to lipid signaling via Pkh1/2 in fungi. All living organisms have to cope with alternating CO2 concentrations as CO2 levels range from very low in the atmosphere (0.04%) to high (5% and more) in other niches, including the human body. In fungi, CO2 is sensed via two pathways. The first regulates virulence in pathogenic yeast by direct activation of adenylyl cyclase. The second pathway, although playing a fundamental role in fungal metabolism, is much less understood. Here the transcription factor Cst6/Rca1 controls carbon homeostasis by regulating carbonic anhydrase expression. Upstream signaling in this pathway remains elusive. We identify Sch9 as the kinase controlling Cst6/Rca1 activity in yeast and demonstrate that this pathway is conserved in pathogenic yeast species, which highlights identified key players as potential pharmacological targets. Furthermore, we provide a direct link between adaptation to changing CO2 conditions and lipid/Pkh1/2 signaling in yeast, thus establishing a new signaling cascade central to metabolic adaptation.
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32
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Yang K, Qin Q, Liu Y, Zhang L, Liang L, Lan H, Chen C, You Y, Zhang F, Wang S. Adenylate Cyclase AcyA Regulates Development, Aflatoxin Biosynthesis and Fungal Virulence in Aspergillus flavus. Front Cell Infect Microbiol 2016; 6:190. [PMID: 28066725 PMCID: PMC5175447 DOI: 10.3389/fcimb.2016.00190] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 12/05/2016] [Indexed: 01/27/2023] Open
Abstract
Aspergillus flavus is one of the most important opportunistic pathogens of crops and animals. The carcinogenic mycotoxin, aflatoxins produced by this pathogen cause a health problem to human and animals. Since cyclic AMP signaling controls a range of physiological processes, like fungal development and infection when responding to extracellular stimuli in fungal pathogens, in this study, we investigated the function of adenylate cyclase, a core component of cAMP signaling, in aflatoxins biosynthesis and virulence on plant seeds in A. flavus. A gene replacement strategy was used to generate the deletion mutant of acyA that encodes the adenylate cyclase. Severe defects in fungal growth, sporulation and sclerotia formation were observed in the acyA deletion mutant. The defect in radical growth could be partially rescued by exogenous cAMP analog. The acyA mutant was also significantly reduced in aflatoxins production and virulence. Similar to the former studies in other fungi, The acyA mutant showed enhancing tolerance to oxidative stress, but more sensitive to heat stress. Overall, the pleiotropic defects of the acyA deletion mutant indicates that the cAMP-PKA pathway is involved in fungal development, aflatoxins biosynthesis and plant seed invasion in A. flavus.
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Affiliation(s)
- Kunlong Yang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Qiuping Qin
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Yinghang Liu
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Limei Zhang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Linlin Liang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Huahui Lan
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Chihao Chen
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Yunchao You
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Feng Zhang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
| | - Shihua Wang
- Fujian Key Laboratory of Pathogenic Fungi and Mycotoxins, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, and School of Life Sciences, Fujian Agriculture and Forestry University Fuzhou, China
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33
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Voisey CR, Christensen MT, Johnson LJ, Forester NT, Gagic M, Bryan GT, Simpson WR, Fleetwood DJ, Card SD, Koolaard JP, Maclean PH, Johnson RD. cAMP Signaling Regulates Synchronised Growth of Symbiotic Epichloë Fungi with the Host Grass Lolium perenne. FRONTIERS IN PLANT SCIENCE 2016; 7:1546. [PMID: 27833620 PMCID: PMC5082231 DOI: 10.3389/fpls.2016.01546] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 10/03/2016] [Indexed: 05/04/2023]
Abstract
The seed-transmitted fungal symbiont, Epichloë festucae, colonizes grasses by infecting host tissues as they form on the shoot apical meristem (SAM) of the seedling. How this fungus accommodates the complexities of plant development to successfully colonize the leaves and inflorescences is unclear. Since adenosine 3', 5'-cyclic monophosphate (cAMP)-dependent signaling is often essential for host colonization by fungal pathogens, we disrupted the cAMP cascade by insertional mutagenesis of the E. festucae adenylate cyclase gene (acyA). Consistent with deletions of this gene in other fungi, acyA mutants had a slow radial growth rate in culture, and hyphae were convoluted and hyper-branched suggesting that fungal apical dominance had been disrupted. Nitro blue tetrazolium (NBT) staining of hyphae showed that cAMP disruption mutants were impaired in their ability to synthesize superoxide, indicating that cAMP signaling regulates accumulation of reactive oxygen species (ROS). Despite significant defects in hyphal growth and ROS production, E. festucae ΔacyA mutants were infectious and capable of forming symbiotic associations with grasses. Plants infected with E. festucae ΔacyA were marginally less robust than the wild-type (WT), however hyphae were hyper-branched, and leaf tissues heavily colonized, indicating that the tight regulation of hyphal growth normally observed in maturing leaves requires functional cAMP signaling.
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Affiliation(s)
- Christine R. Voisey
- Forage Science, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
| | - Michael T. Christensen
- Formally of Forage Improvement, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
| | - Linda J. Johnson
- Forage Science, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
| | - Natasha T. Forester
- Forage Science, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
| | - Milan Gagic
- Forage Science, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
| | - Gregory T. Bryan
- Forage Science, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
| | - Wayne R. Simpson
- Forage Science, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
| | - Damien J. Fleetwood
- Biotelliga Ltd., Institute for Innovation in BiotechnologyAuckland, New Zealand
| | - Stuart D. Card
- Forage Science, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
| | - John P. Koolaard
- Bioinformatics and Statistics Team, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
| | - Paul H. Maclean
- Bioinformatics and Statistics Team, AgResearch Ltd., Lincoln Research CentreChristchurch, New Zealand
| | - Richard D. Johnson
- Forage Science, AgResearch Ltd., Grasslands Research CentrePalmerston North, New Zealand
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34
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Wang W, Wang M, Wang J, Zhu C, Chung KR, Li H. Adenylyl cyclase is required for cAMP production, growth, conidial germination, and virulence in the citrus green mold pathogen Penicillium digitatum. Microbiol Res 2016; 192:11-20. [PMID: 27664719 DOI: 10.1016/j.micres.2016.05.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/23/2016] [Accepted: 05/30/2016] [Indexed: 10/21/2022]
Abstract
Penicillium digitatum is the causative agent of green mold decay on citrus fruit. The cAMP-mediated signaling pathway plays an important role in the transduction of extracellular signals and has been shown to regulate a wide range of developmental processes and pathogenicity in fungal pathogens. We cloned and characterized a Pdac1 gene of P. digitatum, which encodes a polypeptide similar to fungal adenylyl cyclases. Using a loss-of-function mutation in the Pdac1 gene we demonstrated a critical requirement for hyphal growth and conidial germination. Deletion of Pdac1 resulted in decreased accumulation of cAMP and down-regulation of genes encoding a G protein α subunit, both catalytic and regulatory subunits of PKA, and two transcriptional regulators StuA and Som1. Fungal mutants lacking Pdac1 produced abundant conidia, which failed to germinate effectively and displayed an elevated sensitivity to heat treatment. Pdac1 mutant failed to utilize carbohydrates effectively and thus displayed severe growth retardation on rich and synthetic media. Slow growth seen in the Pdac1 mutants could be due to a defect in nutrient sensing and acquisition. Quantitative RT-PCR analysis revealed that Pdac1 was primarily expressed at the early stage of infection. Fungal pathogenicity assayed on citrus fruit revealed that P. digitatum strains impaired for Pdac1 delayed lesion formation. Our results highlight important regulatory roles of adenylyl cyclase-mediated cAMP production in P. digitatum and provide insights into the critical role of cAMP in fungal growth, development and virulence.
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Affiliation(s)
- Weili Wang
- Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Mingshuang Wang
- Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Jiye Wang
- Zhejiang Police College, Hangzhou, Zhejiang 310058, China
| | - Congyi Zhu
- Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Kuang-Ren Chung
- Department of Plant Pathology, National Chung-Hsing University, Taichung, 40227 Taiwan.
| | - Hongye Li
- Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
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Jeswin J, Xie XL, Ji QL, Wang KJ, Liu HP. Proteomic analysis by iTRAQ in red claw crayfish, Cherax quadricarinatus, hematopoietic tissue cells post white spot syndrome virus infection. FISH & SHELLFISH IMMUNOLOGY 2016; 50:288-96. [PMID: 26845698 PMCID: PMC7111676 DOI: 10.1016/j.fsi.2016.01.035] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 01/08/2016] [Accepted: 01/29/2016] [Indexed: 05/23/2023]
Abstract
To elucidate proteomic changes of Hpt cells from red claw crayfish, Cherax quadricarinatus, we have carried out isobaric tags for relative and absolute quantitation (iTRAQ) of cellular proteins at both early (1 hpi) and late stage (12 hpi) post white spot syndrome virus (WSSV) infection. Protein database search revealed 594 protein hits by Mascot, in which 17 and 30 proteins were present as differentially expressed proteins at early and late viral infection, respectively. Generally, these differentially expressed proteins include: 1) the metabolic process related proteins in glycolysis and glucogenesis, DNA replication, nucleotide/amino acid/fatty acid metabolism and protein biosynthesis; 2) the signal transduction related proteins like small GTPases, G-protein-alpha stimulatory subunit, proteins bearing PDZ- or 14-3-3-domains that help holding together and organize signaling complexes, casein kinase I and proteins of the MAP-kinase signal transduction pathway; 3) the immune defense related proteins such as α-2 macroglobulin, transglutaminase and trans-activation response RNA-binding protein 1. Taken together, these protein information shed new light on the host cellular response against WSSV infection in a crustacean cell culture.
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Affiliation(s)
- Joseph Jeswin
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, PR China
| | - Xiao-lu Xie
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, PR China
| | - Qiao-lin Ji
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, PR China
| | - Ke-jian Wang
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, PR China; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Fujian Engineering Laboratory of Marine Bioproducts and Technology, Xiamen 361102, Fujian, PR China
| | - Hai-peng Liu
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361102, Fujian, PR China; Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources, Fujian Engineering Laboratory of Marine Bioproducts and Technology, Xiamen 361102, Fujian, PR China.
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Albataineh MT, Kadosh D. Regulatory roles of phosphorylation in model and pathogenic fungi. Med Mycol 2015; 54:333-52. [PMID: 26705834 PMCID: PMC4818690 DOI: 10.1093/mmy/myv098] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 11/01/2015] [Indexed: 12/25/2022] Open
Abstract
Over the past 20 years, considerable advances have been made toward our understanding
of how post-translational modifications affect a wide variety of biological
processes, including morphology and virulence, in medically important fungi.
Phosphorylation stands out as a key molecular switch and regulatory modification that
plays a critical role in controlling these processes. In this article, we first
provide a comprehensive and up-to-date overview of the regulatory roles that both
Ser/Thr and non-Ser/Thr kinases and phosphatases play in model and pathogenic fungi.
Next, we discuss the impact of current global approaches that are being used to
define the complete set of phosphorylation targets (phosphoproteome) in medically
important fungi. Finally, we provide new insights and perspectives into the potential
use of key regulatory kinases and phosphatases as targets for the development of
novel and more effective antifungal strategies.
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Affiliation(s)
- Mohammad T Albataineh
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
| | - David Kadosh
- Department of Microbiology and Immunology, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229
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Park YD, Williamson PR. Masking the Pathogen: Evolutionary Strategies of Fungi and Their Bacterial Counterparts. J Fungi (Basel) 2015; 1:397-421. [PMID: 29376918 PMCID: PMC5753132 DOI: 10.3390/jof1030397] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 12/03/2015] [Accepted: 12/07/2015] [Indexed: 11/21/2022] Open
Abstract
Pathogens reduce immune recognition of their cell surfaces using a variety of inert structural polysaccharides. For example, capsular polysaccharides play critical roles in microbial survival strategies. Capsules are widely distributed among bacterial species, but relatively rare in eukaryotic microorganisms, where they have evolved considerable complexity in structure and regulation and are exemplified by that of the HIV/AIDS-related fungus Cryptococcus neoformans. Endemic fungi that affect normal hosts such as Histoplasma capsulatum and Blastomyces dermatitidis have also evolved protective polysaccharide coverings in the form of immunologically inert α-(1,3)-glucan polysaccharides to protect their more immunogenic β-(1,3)-glucan-containing cell walls. In this review we provide a comparative update on bacterial and fungal capsular structures and immunogenic properties as well as the polysaccharide masking strategies of endemic fungal pathogens.
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Affiliation(s)
- Yoon-Dong Park
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Building 10, Rm 11N222, MSC 1888, Bethesda, MD 20892, USA.
| | - Peter R Williamson
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 9000 Rockville Pike, Building 10, Rm 11N222, MSC 1888, Bethesda, MD 20892, USA.
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Abstract
Enzymes play key roles in fungal pathogenesis. Manipulation of enzyme expression or activity can significantly alter the infection process, and enzyme expression profiles can be a hallmark of disease. Hence, enzymes are worthy targets for better understanding pathogenesis and identifying new options for combatting fungal infections. Advances in genomics, proteomics, transcriptomics, and mass spectrometry have enabled the identification and characterization of new fungal enzymes. This review focuses on recent developments in the virulence-associated enzymes from Cryptococcus neoformans. The enzymatic suite of C. neoformans has evolved for environmental survival, but several of these enzymes play a dual role in colonizing the mammalian host. We also discuss new therapeutic and diagnostic strategies that could be based on the underlying enzymology.
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Nogueira KMV, Costa MDN, de Paula RG, Mendonça-Natividade FC, Ricci-Azevedo R, Silva RN. Evidence of cAMP involvement in cellobiohydrolase expression and secretion by Trichoderma reesei in presence of the inducer sophorose. BMC Microbiol 2015; 15:195. [PMID: 26424592 PMCID: PMC4590280 DOI: 10.1186/s12866-015-0536-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 09/25/2015] [Indexed: 01/08/2023] Open
Abstract
Background The signaling second messenger cyclic AMP (cAMP) regulates many aspects of cellular function in all organisms. Previous studies have suggested a role for cAMP in the regulation of gene expression of cellulolytic enzymes in Trichoderma reesei (anamorph of Hypocrea jecorina). Methods The effects of cAMP in T. reesei were analyzed through both activity and expression of cellulase, intracellular cAMP level measurement, western blotting, indirect immunofluorescence and confocal microscopy. Results To elucidate the involvement of cAMP in the cellulase expression, we analyzed the growth of the mutant strain ∆acy1 and its parental strain QM9414 in the presence of the inducers cellulose, cellobiose, lactose, or sophorose, and the repressor glucose. Our results indicated that cAMP regulates the expression of cellulase in a carbon source-dependent manner. The expression cel7a, and cel6a genes was higher in the presence of sophorose than in the presence of cellulose, lactose, cellobiose, or glucose. Moreover, intracellular levels of cAMP were up to four times higher in the presence of sophorose compared to other carbon sources. Concomitantly, our immunofluorescence microscopy and western blot data suggest that in the presence of sophorose, cAMP may regulate secretion of cellulolytic enzymes in T. reesei. Conclusions These results allow us to better understand the role of cAMP and expand our knowledge on the signal transduction pathways involved in the regulation of cellulase expression in T. reesei. Finally, our data may help develop new strategies to improve the expression of cel7a and cel6a genes, and therefore, favor their application in several biotechnology fields. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0536-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Karoline Maria Vieira Nogueira
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil.
| | - Mariana do Nascimento Costa
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil.
| | - Renato Graciano de Paula
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil.
| | - Flávia Costa Mendonça-Natividade
- Department of Cell Biology and Molecular and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil.
| | - Rafael Ricci-Azevedo
- Department of Cell Biology and Molecular and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil.
| | - Roberto Nascimento Silva
- Department of Biochemistry and Immunology, Ribeirão Preto Medical School, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil.
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A Gβ protein and the TupA Co-Regulator Bind to Protein Kinase A Tpk2 to Act as Antagonistic Molecular Switches of Fungal Morphological Changes. PLoS One 2015; 10:e0136866. [PMID: 26334875 PMCID: PMC4559445 DOI: 10.1371/journal.pone.0136866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/09/2015] [Indexed: 11/19/2022] Open
Abstract
The human pathogenic fungus Paracoccidioides brasiliensis (Pb) undergoes a morphological transition from a saprobic mycelium to pathogenic yeast that is controlled by the cAMP-signaling pathway. There is a change in the expression of the Gβ-protein PbGpb1, which interacts with adenylate cyclase, during this morphological transition. We exploited the fact that the cAMP-signaling pathway of Saccharomyces cerevisiae does not include a Gβ-protein to probe the functional role of PbGpb1. We present data that indicates that PbGpb1 and the transcriptional regulator PbTupA both bind to the PKA protein PbTpk2. PbTPK2 was able to complement a TPK2Δ strain of S. cerevisiae, XPY5a/α, which was defective in pseudohyphal growth. Whilst PbGPB1 had no effect on the parent S. cerevisiae strain, MLY61a/α, it repressed the filamentous growth of XPY5a/α transformed with PbTPK2, behaviour that correlated with a reduced expression of the floculin FLO11. In vitro, PbGpb1 reduced the kinase activity of PbTpk2, suggesting that inhibition of PbTpk2 by PbGpb1 reduces the level of expression of Flo11, antagonizing the filamentous growth of the cells. In contrast, expressing the co-regulator PbTUPA in XPY5a/α cells transformed with PbTPK2, but not untransformed cells, induced hyperfilamentous growth, which could be antagonized by co-transforming the cells with PbGPB1. PbTUPA was unable to induce the hyperfilamentous growth of a FLO8Δ strain, suggesting that PbTupA functions in conjunction with the transcription factor Flo8 to control Flo11 expression. Our data indicates that P. brasiliensis PbGpb1 and PbTupA, both of which have WD/β-propeller structures, bind to PbTpk2 to act as antagonistic molecular switches of cell morphology, with PbTupA and PbGpb1 inducing and repressing filamentous growth, respectively. Our findings define a potential mechanism for controlling the morphological switch that underpins the virulence of dimorphic fungi.
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Zhang P, Wei D, Li Z, Sun Z, Pan J, Zhu X. Cryptococcal phosphoglucose isomerase is required for virulence factor production, cell wall integrity and stress resistance. FEMS Yeast Res 2015; 15:fov072. [DOI: 10.1093/femsyr/fov072] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/02/2015] [Indexed: 01/03/2023] Open
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Choi J, Jung WH, Kronstad JW. The cAMP/protein kinase A signaling pathway in pathogenic basidiomycete fungi: Connections with iron homeostasis. J Microbiol 2015; 53:579-87. [PMID: 26231374 DOI: 10.1007/s12275-015-5247-5] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/03/2015] [Accepted: 07/03/2015] [Indexed: 12/26/2022]
Abstract
A number of pathogenic species of basidiomycete fungi are either life-threatening pathogens of humans or major economic pests for crop production. Sensing the host is a key aspect of pathogen proliferation during disease, and signal transduction pathways are critically important for detecting environmental conditions and facilitating adaptation. This review focuses on the contributions of the cAMP/protein kinase A (PKA) signaling pathway in Cryptococcus neoformans, a species that causes meningitis in humans, and Ustilago maydis, a model phytopathogen that causes a smut disease on maize. Environmental sensing by the cAMP/PKA pathway regulates the production of key virulence traits in C. neoformans including the polysaccharide capsule and melanin. For U. maydis, the pathway controls the dimorphic transition from budding growth to the filamentous cell type required for proliferation in plant tissue. We discuss recent advances in identifying new components of the cAMP/PKA pathway in these pathogens and highlight an emerging theme that pathway signaling influences iron acquisition.
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Affiliation(s)
- Jaehyuk Choi
- Division of Life Sciences, and Culture Collection and DNA Bank of Mushrooms, Incheon National University, Incheon, 406-772, Republic of Korea
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Hu G, Caza M, Cadieux B, Bakkeren E, Do E, Jung WH, Kronstad JW. The endosomal sorting complex required for transport machinery influences haem uptake and capsule elaboration in Cryptococcus neoformans. Mol Microbiol 2015; 96:973-92. [PMID: 25732100 DOI: 10.1111/mmi.12985] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2015] [Indexed: 11/29/2022]
Abstract
Iron availability is a key determinant of virulence in the pathogenic fungus Cryptococcus neoformans. Previous work revealed that the ESCRT (endosomal sorting complex required for transport) protein Vps23 functions in iron acquisition, capsule formation and virulence. Here, we further characterized the ESCRT machinery to demonstrate that defects in the ESCRT-II and III complexes caused reduced capsule attachment, impaired growth on haem and resistance to non-iron metalloprotoporphyrins. The ESCRT mutants shared several phenotypes with a mutant lacking the pH-response regulator Rim101, and in other fungi, the ESCRT machinery is known to activate Rim101 via proteolytic cleavage. We therefore expressed a truncated and activated version of Rim101 in the ESCRT mutants and found that this allele restored capsule formation but not growth on haem, thus suggesting a Rim101-independent contribution to haem uptake. We also demonstrated that the ESCRT machinery acts downstream of the cAMP/protein kinase A pathway to influence capsule elaboration. Defects in the ESCRT components also attenuated virulence in macrophage survival assays and a mouse model of cryptococcosis to a greater extent than reported for loss of Rim101. Overall, these results indicate that the ESCRT complexes function in capsule elaboration, haem uptake and virulence via Rim101-dependent and independent mechanisms.
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Affiliation(s)
- Guanggan Hu
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Mélissa Caza
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Brigitte Cadieux
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Erik Bakkeren
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
| | - Eunsoo Do
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 456-756, Republic of Korea
| | - Won Hee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 456-756, Republic of Korea
| | - James W Kronstad
- Michael Smith Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, BC, V6T 1Z4, Canada
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Crystal structure of Gib2, a signal-transducing protein scaffold associated with ribosomes in Cryptococcus neoformans. Sci Rep 2015; 5:8688. [PMID: 25732347 PMCID: PMC4894404 DOI: 10.1038/srep08688] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 01/27/2015] [Indexed: 11/16/2022] Open
Abstract
The atypical Gβ-like/RACK1 Gib2 protein promotes cAMP signalling that plays a central role in regulating the virulence of Cryptococcus neoformans. Gib2 contains a seven-bladed β transducin structure and is emerging as a scaffold protein interconnecting signalling pathways through interactions with various protein partners. Here, we present the crystal structure of Gib2 at a 2.2-Å resolution. The structure allows us to analyse the association between Gib2 and the ribosome, as well as to identify the Gib2 amino acid residues involved in ribosome binding. Our studies not only suggest that Gib2 has a role in protein translation but also present Gib2 as a physical link at the crossroads of various regulatory pathways important for the growth and virulence of C. neoformans.
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Ren P, Chaturvedi V, Chaturvedi S. Carbon dioxide is a powerful inducer of monokaryotic hyphae and spore development in Cryptococcus gattii and carbonic anhydrase activity is dispensable in this dimorphic transition. PLoS One 2014; 9:e113147. [PMID: 25478697 PMCID: PMC4257545 DOI: 10.1371/journal.pone.0113147] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 10/22/2014] [Indexed: 12/02/2022] Open
Abstract
Cryptococcus gattii is unique among human pathogenic fungi with specialized ecological niche on trees. Since leaves concentrate CO2, we investigated the role of this gaseous molecule in C. gattii biology and virulence. We focused on the genetic analyses of β-carbonic anhydrase (β-CA) encoded by C. gattii CAN1 and CAN2 as later is critical for CO2 sensing in a closely related pathogen C. neoformans. High CO2 conditions induced robust development of monokaryotic hyphae and spores in C. gattii. Conversely, high CO2 completely repressed hyphae development in sexual mating. Both CAN1 and CAN2 were dispensable for CO2 induced morphogenetic transitions. However, C. gattii CAN2 was essential for growth in ambient air similar to its reported role in C. neoformans. Both can1 and can2 mutants retained full pathogenic potential in vitro and in vivo. These results provide insight into C. gattii adaptation for arboreal growth and production of infectious propagules by β-CA independent mechanism(s).
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Affiliation(s)
- Ping Ren
- Mycology Laboratory, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York, United States of America
| | - Vishnu Chaturvedi
- Mycology Laboratory, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York, United States of America; Department of Biomedical Sciences, School of Public Health, State University at New York, Albany, New York, United States of America
| | - Sudha Chaturvedi
- Mycology Laboratory, Wadsworth Center, New York State Department of Health, 120 New Scotland Avenue, Albany, New York, United States of America; Department of Biomedical Sciences, School of Public Health, State University at New York, Albany, New York, United States of America
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A Ric8/synembryn homolog promotes Gpa1 and Gpa2 activation to respectively regulate cyclic AMP and pheromone signaling in Cryptococcus neoformans. EUKARYOTIC CELL 2014; 13:1290-9. [PMID: 25084863 DOI: 10.1128/ec.00109-14] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The G protein α subunits Gpa1, Gpa2, and Gpa3 mediate signal transduction and are important in the growth and virulence of Cryptococcus neoformans. To understand how Gpa1 functions without a conventional Gβ subunit, we characterized a resistance to inhibitors of cholinesterase 8 (Ric8) homolog from C. neoformans, which shares amino acid sequence homology with other Ric8 proteins that exhibit guanine nucleotide exchange factor (GEF) activity toward Gα. We found that the ric8 mutant was reduced in capsule size and melanin formation, which could be suppressed by cyclic AMP (cAMP) supplementation or by introducing the activated GPA1(Q284L) allele. Consistent with the fact that Ric8 participates in cAMP signaling to regulate virulence, the ric8 mutant was attenuated in virulence toward mice. Interestingly, disruption of RIC8 also resulted in opposing effects on pheromone signaling, as the ric8 mutant showed reduced mating but an enhanced ability to induce the pheromone response in the mating partner. To identify Ric8 functional mechanisms, we examined the interactions between Ric8 and the three Gα proteins. Ric8 interacted with Gpa1 and Gpa2, but not Gpa3. The presence of Gpa1(Q284L) negatively affected its interaction with Ric8, whereas the activated Gpa2(Q203L) allele abolished the interaction. Collectively, these findings suggest that Ric8 functions as a GEF to facilitate the activation of Gpa1-cAMP signaling and to promote Gpa2, affecting mating efficiency. Our study highlights the distinct and conserved characteristics associated with G protein signaling and contributes to our overall understanding of how G protein α subunits function with or without a canonical Gβ partner in C. neoformans.
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Kwon-Chung KJ, Fraser JA, Doering TL, Wang Z, Janbon G, Idnurm A, Bahn YS. Cryptococcus neoformans and Cryptococcus gattii, the etiologic agents of cryptococcosis. Cold Spring Harb Perspect Med 2014; 4:a019760. [PMID: 24985132 PMCID: PMC4066639 DOI: 10.1101/cshperspect.a019760] [Citation(s) in RCA: 312] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cryptococcus neoformans and Cryptococcus gattii are the two etiologic agents of cryptococcosis. They belong to the phylum Basidiomycota and can be readily distinguished from other pathogenic yeasts such as Candida by the presence of a polysaccharide capsule, formation of melanin, and urease activity, which all function as virulence determinants. Infection proceeds via inhalation and subsequent dissemination to the central nervous system to cause meningoencephalitis. The most common risk for cryptococcosis caused by C. neoformans is AIDS, whereas infections caused by C. gattii are more often reported in immunocompetent patients with undefined risk than in the immunocompromised. There have been many chapters, reviews, and books written on C. neoformans. The topics we focus on in this article include species description, pathogenesis, life cycle, capsule, and stress response, which serve to highlight the specializations in virulence that have occurred in this unique encapsulated melanin-forming yeast that causes global deaths estimated at more than 600,000 annually.
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Affiliation(s)
- Kyung J Kwon-Chung
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - James A Fraser
- Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, Queensland 4072, Australia
| | - Tamara L Doering
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Zhou Wang
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Guilhem Janbon
- Unité Biologie et Pathogénicité Fongiques, Institut Pasteur, 75015 Paris, France
| | - Alexander Idnurm
- Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri, Kansas City, Missouri 64110
| | - Yong-Sun Bahn
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea
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Hu S, Zhou X, Gu X, Cao S, Wang C, Xu JR. The cAMP-PKA pathway regulates growth, sexual and asexual differentiation, and pathogenesis in Fusarium graminearum. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:557-66. [PMID: 24450772 DOI: 10.1094/mpmi-10-13-0306-r] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Like many other filamentous ascomycetes, Fusarium graminearum contains two genes named CPK1 and CPK2 that encode the catalytic subunits of cyclic AMP (cAMP)-dependent protein kinase A (PKA). To determine the role of cAMP signaling in pathogenesis and development in F. graminearum, we functionally characterized these two genes. In addition, we generated and characterized the cpk1 cpk2 double and fac1 adenylate cyclase gene deletion mutants. The cpk1 mutant was significantly reduced in vegetative growth, conidiation, and deoxynivalenol production but it had increased tolerance to elevated temperatures. It was defective in the production of penetration branches on plant surfaces, colonization of wheat rachises, and spreading in flowering wheat heads. Deletion of CPK1 had no effect on perithecium development but the cpk1 mutant was defective in ascospore maturation and releasing. In contrast, the cpk2 mutant had no detectable phenotypes, suggesting that CPK2 contributes minimally to PKA activities in F. graminearum. Nevertheless, the cpk1 cpk2 double mutant had more severe defects in vegetative growth and rarely produced morphologically abnormal conidia. The double mutant, unlike the cpk1 or cpk2 mutant, was nonpathogenic and failed to form perithecia on self-mating plates. Therefore, CPK1 and CPK2 must have overlapping functions in vegetative growth, differentiation, and plant infection in F. graminearum. The fac1 mutant was also nonpathogenic and had growth defects similar to those of the cpk1 cpk2 mutant. However, deletion of FAC1 had no effect on conidium morphology. These results indicated that CPK1 is the major PKA catalytic subunit gene and that the cAMP-PKA pathway plays critical roles in hyphal growth, conidiation, ascosporogenesis, and plant infection in F. graminearum.
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Wang Y, Shen G, Gong J, Shen D, Whittington A, Qing J, Treloar J, Boisvert S, Zhang Z, Yang C, Wang P. Noncanonical Gβ Gib2 is a scaffolding protein promoting cAMP signaling through functions of Ras1 and Cac1 proteins in Cryptococcus neoformans. J Biol Chem 2014; 289:12202-16. [PMID: 24659785 DOI: 10.1074/jbc.m113.537183] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Gβ-like/RACK1 functions as a key mediator of various pathways and contributes to numerous cellular functions in eukaryotic organisms. In the pathogenic fungus Cryptococcus neoformans, noncanonical Gβ Gib2 promotes cAMP signaling in cells lacking normal Gpa1 function while displaying versatility in interactions with Gα Gpa1, protein kinase Pkc1, and endocytic intersectin Cin1. To elucidate the Gib2 functional mechanism(s), we demonstrate that Gib2 is required for normal growth and virulence. We show that Gib2 directly binds to Gpa1 and Gγ Gpg1/Gpg2 and that it interacts with phosphodiesterase Pde2 and monomeric GTPase Ras1. Pde2 remains functionally dispensable, but Ras1 is found to associate with adenylyl cyclase Cac1 through the conserved Ras association domain. In addition, the ras1 mutant exhibits normal capsule formation, whereas the ras1 gpa1 mutant displays enhanced capsule formation, and the ras1 gpa1 cac1 mutant is acapsular. Collectively, these findings suggest that Gib2 promotes cAMP levels by relieving an inhibitory function of Ras1 on Cac1 in the absence of Gpa1. In addition, using GST affinity purification combined with mass spectrometry, we identified 47 additional proteins that interact with Gib2. These proteins have putative functions ranging from signal transduction, energy generation, metabolism, and stress response to ribosomal function. After establishing and validating a protein-protein interactive network, we believe Gib2 to be a key adaptor/scaffolding protein that drives the formation of various protein complexes required for growth and virulence. Our study reveals Gib2 as an essential component in deciphering the complexity of regulatory networks that control growth and virulence in C. neoformans.
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Affiliation(s)
- Yanli Wang
- From the Research Institute for Children, Children's Hospital, New Orleans, Louisiana 70118
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Upadhya R, Kim H, Jung KW, Park G, Lam W, Lodge JK, Bahn YS. Sulphiredoxin plays peroxiredoxin-dependent and -independent roles via the HOG signalling pathway in Cryptococcus neoformans and contributes to fungal virulence. Mol Microbiol 2013; 90:630-648. [PMID: 23998805 PMCID: PMC3943550 DOI: 10.1111/mmi.12388] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2013] [Indexed: 12/11/2023]
Abstract
Mechanisms of oxidative stress resistance are crucial virulence factors for survival and proliferation of fungal pathogens within the human host. In this study we have identified and functionally characterized the role of sulphiredoxin, Srx1, in oxidative stress resistance of Cryptococcus neoformans causing fungal meningoencephalitis and regulation of peroxiredoxins, Tsa1 and Tsa3, and thioredoxins, Trx1 and Trx2. The C. neoformans HOG (High Osmolarity Glycerol response) pathway was essential for the transcriptional regulation of SRX1 under peroxide stress conditions. A gene deletion study revealed that Srx1 was required for cells to counteract peroxide stress, but not other oxidative damaging agents. HOG1 was found to be essential for the induction of adaptive response to peroxide stress with concurrent repression of ergosterol biosynthesis in an SRX1-independent manner. Consistent with this, phosphorylation of C. neoformans Hog1 was modulated by both low and high doses of exogenous hydrogen peroxide treatment. Immunoblot analysis using the C. neoformans Tsa1 specific antibody revealed that both Srx1 and Trx1 were essential for recycling of oxidized Tsa1. In addition to its role in peroxide sensing and response C. neoformans Srx1 was also found to be required for a peroxiredoxin-independent function in promoting fungicide-dependent cell swelling and growth arrest. Finally we showed the importance of C. neoformans Srx1 in fungal pathogenesis by demonstrating its requirement for full virulence using a mouse infection model.
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Affiliation(s)
- Rajendra Upadhya
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Hyelim Kim
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Kwang-Woo Jung
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Goun Park
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
| | - Woei Lam
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Jennifer K. Lodge
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yong-Sun Bahn
- Department of Biotechnology, Center for Fungal Pathogenesis, College of Life Science and Biotechnology, Yonsei University, Seoul, Korea
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