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Maji A, Soutar CP, Zhang J, Lewandowska A, Uno BE, Yan S, Shelke Y, Murhade G, Nimerovsky E, Borcik CG, Arango AS, Lange JD, Marin-Toledo JP, Lyu Y, Bailey KL, Roady PJ, Holler JT, Khandelwal A, SantaMaria AM, Sanchez H, Juvvadi PR, Johns G, Hageman MJ, Krise J, Gebremariam T, Youssef EG, Bartizal K, Marr KA, Steinbach WJ, Ibrahim AS, Patterson TF, Wiederhold NP, Andes DR, Pogorelov TV, Schwieters CD, Fan TM, Rienstra CM, Burke MD. Tuning sterol extraction kinetics yields a renal-sparing polyene antifungal. Nature 2023; 623:1079-1085. [PMID: 37938782 PMCID: PMC10883201 DOI: 10.1038/s41586-023-06710-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Accepted: 10/04/2023] [Indexed: 11/09/2023]
Abstract
Decades of previous efforts to develop renal-sparing polyene antifungals were misguided by the classic membrane permeabilization model1. Recently, the clinically vital but also highly renal-toxic small-molecule natural product amphotericin B was instead found to kill fungi primarily by forming extramembraneous sponge-like aggregates that extract ergosterol from lipid bilayers2-6. Here we show that rapid and selective extraction of fungal ergosterol can yield potent and renal-sparing polyene antifungals. Cholesterol extraction was found to drive the toxicity of amphotericin B to human renal cells. Our examination of high-resolution structures of amphotericin B sponges in sterol-free and sterol-bound states guided us to a promising structural derivative that does not bind cholesterol and is thus renal sparing. This derivative was also less potent because it extracts ergosterol more slowly. Selective acceleration of ergosterol extraction with a second structural modification yielded a new polyene, AM-2-19, that is renal sparing in mice and primary human renal cells, potent against hundreds of pathogenic fungal strains, resistance evasive following serial passage in vitro and highly efficacious in animal models of invasive fungal infections. Thus, rational tuning of the dynamics of interactions between small molecules may lead to better treatments for fungal infections that still kill millions of people annually7,8 and potentially other resistance-evasive antimicrobials, including those that have recently been shown to operate through supramolecular structures that target specific lipids9.
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Affiliation(s)
- Arun Maji
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Molecule Maker Lab, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Corinne P Soutar
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Jiabao Zhang
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Agnieszka Lewandowska
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Brice E Uno
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Su Yan
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Yogesh Shelke
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Ganesh Murhade
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Evgeny Nimerovsky
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department for NMR-Based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany
| | - Collin G Borcik
- Molecule Maker Lab, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI, USA
| | - Andres S Arango
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Justin D Lange
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | | | - Yinghuan Lyu
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
- Department of Pathology, Renaissance School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Keith L Bailey
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Patrick J Roady
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jordan T Holler
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Anuj Khandelwal
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Anna M SantaMaria
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- National Institute of Child Health and Human Development, Bethesda, MD, USA
| | - Hiram Sanchez
- Department of Medicine, Section of Infectious Disease, University of Wisconsin-Madison, Madison, WI, USA
| | - Praveen R Juvvadi
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | | | - Michael J Hageman
- Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, KS, USA
| | - Joanna Krise
- Department of Pharmaceutical Chemistry, The University of Kansas, Lawrence, KS, USA
| | | | - Eman G Youssef
- Division of Infectious Diseases, The Lundquist Institute, Torrance, CA, USA
| | | | | | - William J Steinbach
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, AR, USA
- Arkansas Children's Research Institute, Little Rock, AR, USA
| | - Ashraf S Ibrahim
- Division of Infectious Diseases, The Lundquist Institute, Torrance, CA, USA
- David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Thomas F Patterson
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - Nathan P Wiederhold
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA
| | - David R Andes
- Department of Medicine, Section of Infectious Disease, University of Wisconsin-Madison, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
| | - Taras V Pogorelov
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Charles D Schwieters
- Computational Biomolecular Magnetic Resonance Core, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Timothy M Fan
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
- Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Chad M Rienstra
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI, USA.
- National Magnetic Resonance Facility at Madison, University of Wisconsin-Madison, Madison, WI, USA.
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI, USA.
| | - Martin D Burke
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Carl R. Woese Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA.
- Cancer Center at Illinois, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
- Carle-Illinois College of Medicine, University of Illinois at Urbana-Champaign, Champaign, IL, USA.
- Molecule Maker Lab Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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2
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Rivera A, Young Lim W, Park E, Dome PA, Hoy MJ, Spasojevic I, Sun S, Averette AF, Pina-Oviedo S, Juvvadi PR, Steinbach WJ, Ciofani M, Hong J, Heitman J. Enhanced fungal specificity and in vivo therapeutic efficacy of a C-22-modified FK520 analog against C. neoformans. mBio 2023; 14:e0181023. [PMID: 37737622 PMCID: PMC10653846 DOI: 10.1128/mbio.01810-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 09/23/2023] Open
Abstract
IMPORTANCE Fungal infections cause significant morbidity and mortality globally. The therapeutic armamentarium against these infections is limited, and the development of antifungal drugs has been hindered by the evolutionary conservation between fungi and the human host. With rising resistance to the current antifungal arsenal and an increasing at-risk population, there is an urgent need for the development of new antifungal compounds. The FK520 analogs described in this study display potent antifungal activity as a novel class of antifungals centered on modifying an existing orally active FDA-approved therapy. This research advances the development of much-needed newer antifungal treatment options with novel mechanisms of action.
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Affiliation(s)
- Angela Rivera
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA
| | - Won Young Lim
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - Eunchong Park
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Patrick A. Dome
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - Michael J. Hoy
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Ivan Spasojevic
- Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
| | - Sheng Sun
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Anna Floyd Averette
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Sergio Pina-Oviedo
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, USA
| | - Praveen R. Juvvadi
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - William J. Steinbach
- Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Maria Ciofani
- Department of Integrative Immunobiology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Jiyong Hong
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - Joseph Heitman
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
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3
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Rivera A, Lim WY, Park E, Dome PA, Hoy MJ, Spasojevic I, Sun S, Averette AF, Pina-Oviedo S, Juvvadi PR, Steinbach WJ, Ciofani M, Hong J, Heitman J. Enhanced fungal specificity and in vivo therapeutic efficacy of a C-22 modified FK520 analog against C. neoformans. bioRxiv 2023:2023.06.05.543712. [PMID: 37333270 PMCID: PMC10274662 DOI: 10.1101/2023.06.05.543712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Fungal infections are of mounting global concern, and the current limited treatment arsenal poses challenges when treating such infections. In particular, infections by Cryptococcus neoformans are associated with high mortality, emphasizing the need for novel therapeutic options. Calcineurin is a protein phosphatase that mediates fungal stress responses, and calcineurin inhibition by the natural product FK506 blocks C. neoformans growth at 37°C. Calcineurin is also required for pathogenesis. However, because calcineurin is conserved in humans, and inhibition with FK506 results in immunosuppression, the use of FK506 as an anti-infective agent is precluded. We previously elucidated the structures of multiple fungal calcineurin-FK506-FKBP12 complexes and implicated the C-22 position on FK506 as a key point for differential modification of ligand inhibition of the mammalian versus fungal target proteins. Through in vitro antifungal and immunosuppressive testing of FK520 (a natural analog of FK506) derivatives, we identified JH-FK-08 as a lead candidate for further antifungal development. JH-FK-08 exhibited significantly reduced immunosuppressive activity and both reduced fungal burden and prolonged survival of infected animals. JH-FK-08 exhibited additive activity in combination with fluconazole in vivo . These findings further advance calcineurin inhibition as an antifungal therapeutic approach. Importance Fungal infections cause significant morbidity and mortality globally. The therapeutic armamentarium against these infections is limited and development of antifungal drugs has been hindered by the evolutionary conservation between fungi and the human host. With rising resistance to the current antifungal arsenal and an increasing at-risk population, there is an urgent need for the development of new antifungal compounds. The FK520 analogs described in this study display potent antifungal activity as a novel class of antifungals centered on modifying an existing orally-active FDA approved therapy. This research advances the development of much needed newer antifungal treatment options with novel mechanisms of action.
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4
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Hoy MJ, Park E, Lee H, Lim WY, Cole DC, DeBouver ND, Bobay BG, Pierce PG, Fox D, Ciofani M, Juvvadi PR, Steinbach W, Hong J, Heitman J. Structure-Guided Synthesis of FK506 and FK520 Analogs with Increased Selectivity Exhibit In Vivo Therapeutic Efficacy against Cryptococcus. mBio 2022; 13:e0104922. [PMID: 35604094 PMCID: PMC9239059 DOI: 10.1128/mbio.01049-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 04/21/2022] [Indexed: 01/04/2023] Open
Abstract
Calcineurin is an essential virulence factor that is conserved across human fungal pathogens, including Cryptococcus neoformans, Aspergillus fumigatus, and Candida albicans. Although an excellent target for antifungal drug development, the serine-threonine phosphatase activity of calcineurin is conserved in mammals, and inhibition of this activity results in immunosuppression. FK506 (tacrolimus) is a naturally produced macrocyclic compound that inhibits calcineurin by binding to the immunophilin FKBP12. Previously, our fungal calcineurin-FK506-FKBP12 structure-based approaches identified a nonconserved region of FKBP12 that can be exploited for fungus-specific targeting. These studies led to the design of an FK506 analog, APX879, modified at the C-22 position, which was less immunosuppressive yet maintained antifungal activity. We now report high-resolution protein crystal structures of fungal FKBP12 and a human truncated calcineurin-FKBP12 bound to a natural FK506 analog, FK520 (ascomycin). Based on information from these structures and the success of APX879, we synthesized and screened a novel panel of C-22-modified compounds derived from both FK506 and FK520. One compound, JH-FK-05, demonstrates broad-spectrum antifungal activity in vitro and is nonimmunosuppressive in vivo. In murine models of pulmonary and disseminated C. neoformans infection, JH-FK-05 treatment significantly reduced fungal burden and extended animal survival alone and in combination with fluconazole. Furthermore, molecular dynamic simulations performed with JH-FK-05 binding to fungal and human FKBP12 identified additional residues outside the C-22 and C-21 positions that could be modified to generate novel FK506 analogs with improved antifungal activity. IMPORTANCE Due to rising rates of antifungal drug resistance and a limited armamentarium of antifungal treatments, there is a paramount need for novel antifungal drugs to treat systemic fungal infections. Calcineurin has been established as an essential and conserved virulence factor in several fungi, making it an attractive antifungal target. However, due to the immunosuppressive action of calcineurin inhibitors, they have not been successfully utilized clinically for antifungal treatment in humans. Recent availability of crystal structures of fungal calcineurin-bound inhibitor complexes has enabled the structure-guided design of FK506 analogs and led to a breakthrough in the development of a compound with increased fungal specificity. The development of a calcineurin inhibitor with reduced immunosuppressive activity and maintained therapeutic antifungal activity would add a significant tool to the treatment options for these invasive fungal infections with exceedingly high rates of mortality.
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Affiliation(s)
- Michael J. Hoy
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
| | - Eunchong Park
- Department of Immunology, Duke University Medical Center, Durham, North Carolina, USA
| | - Hyunji Lee
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - Won Young Lim
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - D. Christopher Cole
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Nicholas D. DeBouver
- UCB Biosciences, Bainbridge Island, Washington, USA
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington, USA
| | | | - Phillip G. Pierce
- UCB Biosciences, Bainbridge Island, Washington, USA
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington, USA
| | - David Fox
- UCB Biosciences, Bainbridge Island, Washington, USA
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, Washington, USA
| | - Maria Ciofani
- Department of Immunology, Duke University Medical Center, Durham, North Carolina, USA
| | - Praveen R. Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - William Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA
| | - Jiyong Hong
- Department of Chemistry, Duke University, Durham, North Carolina, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, USA
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5
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Shwab EK, Juvvadi PR, Shaheen SK, Allen J, Waitt G, Soderblom EJ, Asfaw YG, Moseley MA, Steinbach WJ. Protein Kinase A Regulates Autophagy-Associated Proteins Impacting Growth and Virulence of Aspergillus fumigatus. J Fungi (Basel) 2022; 8:jof8040354. [PMID: 35448585 PMCID: PMC9029100 DOI: 10.3390/jof8040354] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/14/2022] [Accepted: 03/28/2022] [Indexed: 01/07/2023] Open
Abstract
Cellular recycling via autophagy-associated proteins is a key catabolic pathway critical to invasive fungal pathogen growth and virulence in the nutrient-limited host environment. Protein kinase A (PKA) is vital for the growth and virulence of numerous fungal pathogens. However, the underlying basis for its regulation of pathogenesis remains poorly understood in any species. Our Aspergillus fumigatus PKA-dependent whole proteome and phosphoproteome studies employing advanced mass spectroscopic approaches identified numerous previously undefined PKA-regulated proteins in catabolic pathways. Here, we demonstrate reciprocal inhibition of autophagy and PKA activity, and identify 16 autophagy-associated proteins as likely novel PKA-regulated effectors. We characterize the novel PKA-phosphoregulated sorting nexin Atg20, and demonstrate its importance for growth, cell wall stress response, and virulence of A. fumigatus in a murine infection model. Additionally, we identify physical and functional interaction of Atg20 with previously characterized sorting nexin Atg24. Furthermore, we demonstrate the importance of additional uncharacterized PKA-regulated putative autophagy-associated proteins to hyphal growth. Our data presented here indicate that PKA regulates the autophagy pathway much more extensively than previously known, including targeting of novel effector proteins with fungal-specific functions important for invasive disease.
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Affiliation(s)
- E. Keats Shwab
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC 27710, USA; (E.K.S.); (P.R.J.); (S.K.S.); (J.A.IV)
| | - Praveen R. Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC 27710, USA; (E.K.S.); (P.R.J.); (S.K.S.); (J.A.IV)
| | - Shareef K. Shaheen
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC 27710, USA; (E.K.S.); (P.R.J.); (S.K.S.); (J.A.IV)
| | - John Allen
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC 27710, USA; (E.K.S.); (P.R.J.); (S.K.S.); (J.A.IV)
| | - Greg Waitt
- Duke Proteomics Core Facility, Institute for Genome Sciences and Policy, Duke University, Durham, NC 27701, USA; (G.W.); (E.J.S.); (M.A.M.)
| | - Erik J. Soderblom
- Duke Proteomics Core Facility, Institute for Genome Sciences and Policy, Duke University, Durham, NC 27701, USA; (G.W.); (E.J.S.); (M.A.M.)
| | - Yohannes G. Asfaw
- Department of Laboratory Animal Resources, Duke University Medical Center, Durham, NC 27710, USA;
| | - M. Arthur Moseley
- Duke Proteomics Core Facility, Institute for Genome Sciences and Policy, Duke University, Durham, NC 27701, USA; (G.W.); (E.J.S.); (M.A.M.)
| | - William J. Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC 27710, USA; (E.K.S.); (P.R.J.); (S.K.S.); (J.A.IV)
- Department of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC 27710, USA
- Correspondence:
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6
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Xu-Vanpala S, Deerhake ME, Wheaton JD, Parker ME, Juvvadi PR, MacIver N, Ciofani M, Shinohara ML. Functional heterogeneity of alveolar macrophage population based on expression of CXCL2. Sci Immunol 2020; 5:5/50/eaba7350. [PMID: 32769172 DOI: 10.1126/sciimmunol.aba7350] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Accepted: 06/15/2020] [Indexed: 12/21/2022]
Abstract
Alveolar macrophages (AMs) are the major lung-resident macrophages and have contradictory functions. AMs maintain tolerance and tissue homeostasis, but they also initiate strong inflammatory responses. However, such opposing roles within the AM population were not known to be simultaneously generated and coexist. Here, we uncovered heterogeneous AM subpopulations generated in response to two distinct pulmonary fungal infections, Cryptococcus neoformans and Aspergillus fumigatus Some AMs are bona fide sentinel cells that produce chemoattractant CXCL2, which also serves as a marker for AM heterogeneity, in the context of pulmonary fungal infections. However, other AMs do not produce CXCL2 and other pro-inflammatory molecules. Instead, they highly produce anti-inflammatory molecules, including interleukin-10 (IL-10) and complement component 1q (C1q). These two AM subpopulations have distinct metabolic profiles and phagocytic capacities. We report that polarization of pro-inflammatory and anti-inflammatory AM subpopulations is regulated at both epigenetic and transcriptional levels and that these AM subpopulations are generally highly plastic. Our studies have uncovered the role of C1q expression in programming and sustaining anti-inflammatory AMs. Our finding of the AM heterogeneity upon fungal infections suggests a possible pharmacological intervention target to treat fungal infections by tipping the balance of AM subpopulations.
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Affiliation(s)
- Shengjie Xu-Vanpala
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - M Elizabeth Deerhake
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Joshua D Wheaton
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA.,Amgen Research, Amgen Inc., South San Francisco, CA 94080, USA
| | - Morgan E Parker
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Praveen R Juvvadi
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | - Nancie MacIver
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA.,Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA.,Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Maria Ciofani
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA
| | - Mari L Shinohara
- Department of Immunology, Duke University School of Medicine, Durham, NC 27710, USA. .,Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, NC 27710, USA
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7
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Renshaw H, Juvvadi PR, Cole DC, Steinbach WJ. The class V myosin interactome of the human pathogen Aspergillus fumigatus reveals novel interactions with COPII vesicle transport proteins. Biochem Biophys Res Commun 2020; 527:232-237. [PMID: 32446373 PMCID: PMC7248123 DOI: 10.1016/j.bbrc.2020.04.111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 04/21/2020] [Indexed: 11/21/2022]
Abstract
The human fungal pathogen Aspergillus fumigatus causes life-threatening invasive aspergillosis in immunocompromised individuals. Adaptation to the host environment is integral to survival of A. fumigatus and requires the coordination of short- and long-distance vesicular transport to move essential components throughout the fungus. We previously reported the importance of MyoE, the only class V myosin, for hyphal growth and virulence of A. fumigatus. Class V myosins are actin-based, cargo-carrying motor proteins that contain unique binding sites for specific cargo. Specific cargo carried by myosin V has not been identified in any fungus, and previous studies have only identified single components that interact with class V myosins. Here we utilized a mass spectrometry-based whole proteomic approach to identify MyoE interacting proteins in A. fumigatus for the first time. Several proteins previously shown to interact with myosin V through physical and genetic approaches were confirmed, validating our proteomic analysis. Importantly, we identified novel MyoE-interacting proteins, including members of the cytoskeleton network, cell wall synthesis, calcium signaling and a group of coat protein complex II (COPII) proteins involved in the endoplasmic reticulum (ER) to Golgi transport. Furthermore, we analyzed the localization patterns of the COPII proteins, UsoA (Uso1), SrgE (Sec31), and SrgF (Sec23), which suggested a potential role for MyoE in ER to Golgi trafficking.
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Affiliation(s)
- Hilary Renshaw
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Praveen R Juvvadi
- Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA.
| | - D Christopher Cole
- Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA
| | - William J Steinbach
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA; Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA.
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8
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Juvvadi PR, Bobay BG, Gobeil SMC, Cole DC, Venters RA, Heitman J, Spicer LD, Steinbach WJ. FKBP12 dimerization mutations effect FK506 binding and differentially alter calcineurin inhibition in the human pathogen Aspergillus fumigatus. Biochem Biophys Res Commun 2020; 526:48-54. [PMID: 32192767 DOI: 10.1016/j.bbrc.2020.03.062] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 03/10/2020] [Indexed: 01/23/2023]
Abstract
The 12-kDa FK506-binding protein (FKBP12) is the target of the commonly used immunosuppressive drug FK506. The FKBP12-FK506 complex binds to calcineurin and inhibits its activity, leading to immunosuppression and preventing organ transplant rejection. Our recent characterization of crystal structures of FKBP12 proteins in pathogenic fungi revealed the involvement of the 80's loop residue (Pro90) in the active site pocket in self-substrate interaction providing novel evidence on FKBP12 dimerization in vivo. The 40's loop residues have also been shown to be involved in reversible dimerization of FKBP12 in the mammalian and yeast systems. To understand how FKBP12 dimerization affects FK506 binding and influences calcineurin function, we generated Aspergillus fumigatus FKBP12 mutations in the 40's and 50's loop (F37 M/L; W60V). Interestingly, the mutants exhibited variable FK506 susceptibility in vivo indicating differing dimer strengths. In comparison to the 80's loop P90G and V91C mutants, the F37 M/L and W60V mutants exhibited greater FK506 resistance, with the F37M mutation showing complete loss in calcineurin binding in vivo. Molecular dynamics and pulling simulations for each dimeric FKBP12 protein revealed a two-fold increase in dimer strength and significantly higher number of contacts for the F37M, F37L, and W60V mutations, further confirming their varying degree of impact on FK506 binding and calcineurin inhibition in vivo.
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Affiliation(s)
- Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Benjamin G Bobay
- Duke University NMR Center, Duke University Medical Center, Durham, NC, 27710, USA; Department of Biochemistry, Durham, NC, 27710, USA; Department of Radiology, Duke University, Durham, NC, 27710, USA
| | - Sophie M C Gobeil
- Department of Biochemistry, Durham, NC, 27710, USA; Department of Radiology, Duke University, Durham, NC, 27710, USA
| | - D Christopher Cole
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA
| | - Ronald A Venters
- Duke University NMR Center, Duke University Medical Center, Durham, NC, 27710, USA; Department of Biochemistry, Durham, NC, 27710, USA; Department of Radiology, Duke University, Durham, NC, 27710, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Leonard D Spicer
- Duke University NMR Center, Duke University Medical Center, Durham, NC, 27710, USA; Department of Biochemistry, Durham, NC, 27710, USA; Department of Radiology, Duke University, Durham, NC, 27710, USA
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA; Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA.
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9
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Juvvadi PR, Fox D, Bobay BG, Hoy MJ, Gobeil SMC, Venters RA, Chang Z, Lin JJ, Averette AF, Cole DC, Barrington BC, Wheaton JD, Ciofani M, Trzoss M, Li X, Lee SC, Chen YL, Mutz M, Spicer LD, Schumacher MA, Heitman J, Steinbach WJ. Harnessing calcineurin-FK506-FKBP12 crystal structures from invasive fungal pathogens to develop antifungal agents. Nat Commun 2019; 10:4275. [PMID: 31537789 PMCID: PMC6753081 DOI: 10.1038/s41467-019-12199-1] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 08/23/2019] [Indexed: 12/16/2022] Open
Abstract
Calcineurin is important for fungal virulence and a potential antifungal target, but compounds targeting calcineurin, such as FK506, are immunosuppressive. Here we report the crystal structures of calcineurin catalytic (CnA) and regulatory (CnB) subunits complexed with FK506 and the FK506-binding protein (FKBP12) from human fungal pathogens (Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans and Coccidioides immitis). Fungal calcineurin complexes are similar to the mammalian complex, but comparison of fungal and human FKBP12 (hFKBP12) reveals conformational differences in the 40s and 80s loops. NMR analysis, molecular dynamic simulations, and mutations of the A. fumigatus CnA/CnB-FK506-FKBP12-complex identify a Phe88 residue, not conserved in hFKBP12, as critical for binding and inhibition of fungal calcineurin. These differences enable us to develop a less immunosuppressive FK506 analog, APX879, with an acetohydrazine substitution of the C22-carbonyl of FK506. APX879 exhibits reduced immunosuppressive activity and retains broad-spectrum antifungal activity and efficacy in a murine model of invasive fungal infection.
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Affiliation(s)
- Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA.
| | - David Fox
- Beryllium Discovery Corp., 7869 NE Day Road West, Bainbridge Island, WA, 98110, USA
- UCB Pharma., 7869 NE Day Road West, Bainbridge Island, WA, 98110, USA
- Seattle Structural Genomics Center for Infectious Disease (SSGCID), Seattle, WA, USA
| | - Benjamin G Bobay
- Duke University NMR Center, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Biochemistry, Duke University, Durham, NC, 27710, USA
- Department of Radiology, Duke University, Durham, NC, 27710, USA
| | - Michael J Hoy
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Sophie M C Gobeil
- Department of Biochemistry, Duke University, Durham, NC, 27710, USA
- Department of Radiology, Duke University, Durham, NC, 27710, USA
| | - Ronald A Venters
- Duke University NMR Center, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Biochemistry, Duke University, Durham, NC, 27710, USA
- Department of Radiology, Duke University, Durham, NC, 27710, USA
| | - Zanetta Chang
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Jackie J Lin
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Anna Floyd Averette
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - D Christopher Cole
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA
| | - Blake C Barrington
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA
| | - Joshua D Wheaton
- Department of Immunology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Maria Ciofani
- Department of Immunology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Michael Trzoss
- Amplyx Pharmaceuticals, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Xiaoming Li
- Amplyx Pharmaceuticals, 3210 Merryfield Row, San Diego, CA, 92121, USA
- Forge Therapeutics, Inc., 10578 Science Center Drive, San Diego, CA, 92121, USA
| | - Soo Chan Lee
- South Texas Center for Emerging Infectious Diseases, Department of Biology, The University of Texas at San Antonio, San Antonio, TX, 78249, USA
| | - Ying-Lien Chen
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei, 10617, Taiwan
| | - Mitchell Mutz
- Amplyx Pharmaceuticals, 3210 Merryfield Row, San Diego, CA, 92121, USA
- Genentech Inc., 1 DNA Way, San Francisco, CA, 94080, USA
| | - Leonard D Spicer
- Duke University NMR Center, Duke University Medical Center, Durham, NC, 27710, USA
- Department of Biochemistry, Duke University, Durham, NC, 27710, USA
- Department of Radiology, Duke University, Durham, NC, 27710, USA
| | | | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, 27710, USA.
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10
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Shwab EK, Juvvadi PR, Waitt G, Soderblom EJ, Barrington BC, Asfaw YG, Moseley MA, Steinbach WJ. Calcineurin-dependent dephosphorylation of the transcription factor CrzA at specific sites controls conidiation, stress tolerance, and virulence of Aspergillus fumigatus. Mol Microbiol 2019; 112:62-80. [PMID: 30927289 DOI: 10.1111/mmi.14254] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2019] [Indexed: 12/15/2022]
Abstract
Calcium signaling through calcineurin and its major transcription factor (TF), CrzA, is integral to hyphal growth, stress response and virulence of the pathogenic fungus Aspergillus fumigatus, the leading etiology of invasive aspergillosis. Dephosphorylation of CrzA by calcineurin activates the TF, but the specific phosphorylation sites and their roles in the activation/inactivation mechanism are unknown. Mass spectroscopic analysis identified 20 phosphorylation sites, the majority of which were specific to filamentous fungi and distributed throughout the CrzA protein, with particular concentration in a serine-rich region N-terminal to the conserved DNA-binding domain (DBD). Site-directed mutagenesis of phosphorylated residues revealed that CrzA activity during calcium stimulation can only be suppressed by a high degree of phosphorylation in multiple regions of the protein. Our findings further suggest that this regulation is not solely accomplished through control of CrzA nuclear import. Additionally, we demonstrate the importance of the CrzA phosphorylation state in regulating growth, conidiation, calcium and cell wall stress tolerance, and virulence. Finally, we identify two previously undescribed nuclear localization sequences in the DBD. These findings provide novel insight into the phosphoregulation of CrzA which may be exploited to selectively target A. fumigatus.
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Affiliation(s)
- E Keats Shwab
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Greg Waitt
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Erik J Soderblom
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - Blake C Barrington
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Yohannes G Asfaw
- Department of Laboratory Animal Resources, Duke University Medical Center, Durham, NC, USA
| | - M Arthur Moseley
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC, USA
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA.,Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
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11
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Renshaw H, Vargas-Muñiz JM, Juvvadi PR, Richards AD, Waitt G, Soderblom EJ, Moseley MA, Steinbach WJ. The tail domain of the Aspergillus fumigatus class V myosin MyoE orchestrates septal localization and hyphal growth. J Cell Sci 2018; 131:jcs.205955. [PMID: 29222113 DOI: 10.1242/jcs.205955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 12/05/2017] [Indexed: 01/10/2023] Open
Abstract
Myosins are critical motor proteins that contribute to the secretory pathway, polarized growth, and cytokinesis. The globular tail domains of class V myosins have been shown to be important for cargo binding and actin cable organization. Additionally, phosphorylation plays a role in class V myosin cargo choice. Our previous studies on the class V myosin MyoE in the fungal pathogen Aspergillus fumigatus confirmed its requirement for normal morphology and virulence. However, the domains and molecular mechanisms governing the functions of MyoE remain unknown. Here, by analyzing tail mutants, we demonstrate that the tail is required for radial growth, conidiation, septation frequency and MyoE's location at the septum. Furthermore, MyoE is phosphorylated at multiple residues in vivo; however, alanine substitution mutants revealed that no single phosphorylated residue was critical. Importantly, in the absence of the phosphatase calcineurin, an additional residue was phosphorylated in its tail domain. Mutation of this tail residue led to mislocalization of MyoE from the septa. This work reveals the importance of the MyoE tail domain and its phosphorylation/dephosphorylation in the growth and morphology of A. fumigatus.
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Affiliation(s)
- Hilary Renshaw
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - José M Vargas-Muñiz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | - Amber D Richards
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
| | - Greg Waitt
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - Erik J Soderblom
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - M Arthur Moseley
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - William J Steinbach
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA .,Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC 27710, USA
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12
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Juvvadi PR, Moseley MA, Hughes CJ, Soderblom EJ, Lennon S, Perkins SR, Thompson JW, Geromanos SJ, Wildgoose J, Richardson K, Langridge JI, Vissers JPC, Steinbach WJ. Scanning Quadrupole Data-Independent Acquisition, Part B: Application to the Analysis of the Calcineurin-Interacting Proteins during Treatment of Aspergillus fumigatus with Azole and Echinocandin Antifungal Drugs. J Proteome Res 2017; 17:780-793. [PMID: 29251506 DOI: 10.1021/acs.jproteome.7b00499] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcineurin is a critical cell-signaling protein that orchestrates growth, stress response, virulence, and antifungal drug resistance in several fungal pathogens. Blocking calcineurin signaling increases the efficacy of several currently available antifungals and suppresses drug resistance. We demonstrate the application of a novel scanning quadrupole DIA method for the analysis of changes in the proteins coimmunoprecipitated with calcineurin during therapeutic antifungal drug treatments of the deadly human fungal pathogen Aspergillus fumigatus. Our experimental design afforded an assessment of the precision of the method as demonstrated by peptide- and protein-centric analysis from eight replicates of the study pool QC samples. Two distinct classes of clinically relevant antifungal drugs that are guideline recommended for the treatment of invasive "aspergillosis" caused by Aspergillus fumigatus, the azoles (voriconazole) and the echinocandins (caspofungin and micafungin), which specifically target the fungal plasma membrane and the fungal cell wall, respectively, were chosen to distinguish variations occurring in the proteins coimmunoprecipitated with calcineurin. Novel potential interactors were identified in response to the different drug treatments that are indicative of the possible role for calcineurin in regulating these effectors. Notably, treatment with voriconazole showed increased immunoprecipitation of key proteins involved in membrane ergosterol biosynthesis with calcineurin. In contrast, echinocandin (caspofungin or micafungin) treatments caused increased immunoprecipitation of proteins involved in cell-wall biosynthesis and septation. Furthermore, abundant coimmunoprecipitation of ribosomal proteins with calcineurin occurred exclusively in echinocandins treatment, indicating reprogramming of cellular growth mechanisms during different antifungal drug treatments. While variations in the observed calcineurin immunoprecipitated proteins may also be due to changes in their expression levels under different drug treatments, this study suggests an important role for calcineurin-dependent cellular mechanisms in response to antifungal treatment of A. fumigatus that warrants future studies.
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Affiliation(s)
- Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - M Arthur Moseley
- Proteomics and Metabolomics Shared Resource Center for Genomic and Computational Biology, Duke University Medical Center , Durham, North Carolina 27710, United States
| | | | - Erik J Soderblom
- Proteomics and Metabolomics Shared Resource Center for Genomic and Computational Biology, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - Sarah Lennon
- Waters Corporation , Wilmslow SK9 4AX, United Kingdom
| | - Simon R Perkins
- Institute of Integrative Biology, University of Liverpool , Liverpool L69 3BX, United Kingdom
| | - J Will Thompson
- Proteomics and Metabolomics Shared Resource Center for Genomic and Computational Biology, Duke University Medical Center , Durham, North Carolina 27710, United States
| | | | | | | | | | | | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center , Durham, North Carolina 27710, United States.,Department of Molecular Genetics and Microbiology, Duke University Medical Center , Durham, North Carolina 27710, United States
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13
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Moseley MA, Hughes CJ, Juvvadi PR, Soderblom EJ, Lennon S, Perkins SR, Thompson JW, Steinbach WJ, Geromanos SJ, Wildgoose J, Langridge JI, Richardson K, Vissers JPC. Scanning Quadrupole Data-Independent Acquisition, Part A: Qualitative and Quantitative Characterization. J Proteome Res 2017; 17:770-779. [PMID: 28901143 DOI: 10.1021/acs.jproteome.7b00464] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A novel data-independent acquisition (DIA) method incorporating a scanning quadrupole in front of a collision cell and orthogonal acceleration time-of-flight mass analyzer is described. The method has been characterized for the qualitative and quantitative label-free proteomic analysis of complex biological samples. The principle of the scanning quadrupole DIA method is discussed, and analytical instrument characteristics, such as the quadrupole transmission width, scan/integration time, and chromatographic separation, have been optimized in relation to sample complexity for a number of different model proteomes of varying complexity and dynamic range including human plasma, cell lines, and bacteria. In addition, the technological merits over existing DIA approaches are described and contrasted. The qualitative and semiquantitative performance of the method is illustrated for the analysis of relatively simple protein digest mixtures and a well-characterized human cell line sample using untargeted and targeted search strategies. Finally, the results from a human cell line were compared against publicly available data that used similar chromatographic conditions but were acquired with DDA technology and alternative mass analyzer systems. Qualitative comparison showed excellent concordance of results with >90% overlap of the detected proteins.
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Affiliation(s)
- M Arthur Moseley
- Proteomics and Metabolomics Shared Resource Center for Genomic and Computational Biology, Duke University Medical Center , Durham, North Carolina 27710, United States
| | | | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - Erik J Soderblom
- Proteomics and Metabolomics Shared Resource Center for Genomic and Computational Biology, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - Sarah Lennon
- Waters Corporation , Wilmslow SK9 4AX, United Kingdom
| | - Simon R Perkins
- Institute of Integrative Biology, University of Liverpool , Liverpool L69 3BX, United Kingdom
| | - J Will Thompson
- Proteomics and Metabolomics Shared Resource Center for Genomic and Computational Biology, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center , Durham, North Carolina 27710, United States.,Department of Molecular Genetics and Microbiology, Duke University Medical Center , Durham, North Carolina 27710, United States
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14
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Shwab EK, Juvvadi PR, Waitt G, Soderblom EJ, Moseley MA, Nicely NI, Steinbach WJ. Phosphorylation of Aspergillus fumigatus PkaR impacts growth and cell wall integrity through novel mechanisms. FEBS Lett 2017; 591:3730-3744. [PMID: 29067690 PMCID: PMC5705279 DOI: 10.1002/1873-3468.12886] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/06/2017] [Accepted: 10/11/2017] [Indexed: 11/06/2022]
Abstract
Protein kinase A (PKA) signaling is essential for growth and virulence of the fungal pathogen Aspergillus fumigatus. Little is known concerning the regulation of this pathway in filamentous fungi. Employing liquid chromatography-tandem mass spectroscopy, we identified novel phosphorylation sites on the regulatory subunit PkaR, distinct from those previously identified in mammals and yeasts, and demonstrated the importance of two phosphorylation clusters for hyphal growth and cell wall-stress response. We also identified key differences in the regulation of PKA subcellular localization in A. fumigatus compared with other species. This is the first analysis of the phosphoregulation of a PKA regulatory subunit in a filamentous fungus and uncovers critical mechanistic differences between PKA regulation in filamentous fungi compared with mammals and yeast species, suggesting divergent targeting opportunities.
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Affiliation(s)
- E. Keats Shwab
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA
| | - Praveen R. Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA
| | - Greg Waitt
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham NC, USA
| | - Erik J. Soderblom
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham NC, USA
| | - M. Arthur Moseley
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham NC, USA
| | - Nathan I. Nicely
- Duke Human Vaccine Institute, Duke University School of Medicine, Durham, NC, USA
| | - William J. Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC, USA
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15
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Juvvadi PR. Balancing iron and calcium: Flavin carrier family proteins in Aspergillus fumigatus virulence. Virulence 2017; 8:621-624. [PMID: 27820672 PMCID: PMC5626335 DOI: 10.1080/21505594.2016.1257459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 10/31/2016] [Indexed: 10/20/2022] Open
Affiliation(s)
- Praveen R. Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University School of Medicine, Durham, NC, USA
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16
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Vargas-Muñiz JM, Renshaw H, Waitt G, Soderblom EJ, Moseley MA, Palmer JM, Juvvadi PR, Keller NP, Steinbach WJ. Caspofungin exposure alters the core septin AspB interactome of Aspergillus fumigatus. Biochem Biophys Res Commun 2017; 485:221-226. [PMID: 28238781 PMCID: PMC5384791 DOI: 10.1016/j.bbrc.2017.02.116] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 02/22/2017] [Indexed: 11/24/2022]
Abstract
Aspergillus fumigatus, the main etiological agent of invasive aspergillosis, is a leading cause of death in immunocompromised patients. Septins, a conserved family of GTP-binding proteins, serve as scaffolding proteins to recruit enzymes and key regulators to different cellular compartments. Deletion of the A. fumigatus septin aspB increases susceptibility to the echinocandin antifungal caspofungin. However, how AspB mediates this response to caspofungin is unknown. Here, we characterized the AspB interactome under basal conditions and after exposure to a clinically relevant concentration of caspofungin. While A. fumigatus AspB interacted with 334 proteins, including kinases, cell cycle regulators, and cell wall synthesis-related proteins under basal growth conditions, caspofungin exposure altered AspB interactions. A total of 69 of the basal interactants did not interact with AspB after exposure to caspofungin, and 54 new interactants were identified following caspofungin exposure. We generated A. fumigatus deletion strains for 3 proteins (ArpB, Cyp4, and PpoA) that only interacted with AspB following exposure to caspofungin that were previously annotated as induced after exposure to antifungal agents, yet only PpoA was implicated in the response to caspofungin. Taken together, we defined how the septin AspB interactome is altered in the presence of a clinically relevant antifungal.
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Affiliation(s)
- José M Vargas-Muñiz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States
| | - Hilary Renshaw
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States
| | - Greg Waitt
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC, United States
| | - Erik J Soderblom
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC, United States
| | - M Arthur Moseley
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham, NC, United States
| | - Jonathan M Palmer
- U.S. Forest Service, Northern Research Station, Center for Forest Mycology Research, Madison, WI, United States; Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, United States
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, United States
| | - William J Steinbach
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States; Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, United States.
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17
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Juvvadi PR, Lee SC, Heitman J, Steinbach WJ. Calcineurin in fungal virulence and drug resistance: Prospects for harnessing targeted inhibition of calcineurin for an antifungal therapeutic approach. Virulence 2017; 8:186-197. [PMID: 27325145 PMCID: PMC5354160 DOI: 10.1080/21505594.2016.1201250] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 01/26/2023] Open
Abstract
Increases in the incidence and mortality due to the major invasive fungal infections such as aspergillosis, candidiasis and cryptococcosis caused by the species of Aspergillus, Candida and Cryptococcus, are a growing threat to the immunosuppressed patient population. In addition to the limited armamentarium of the current classes of antifungal agents available (pyrimidine analogs, polyenes, azoles, and echinocandins), their toxicity, efficacy and the emergence of resistance are major bottlenecks limiting successful patient outcomes. Although these drugs target distinct fungal pathways, there is an urgent need to develop new antifungals that are more efficacious, fungal-specific, with reduced or no toxicity and simultaneously do not induce resistance. Here we review several lines of evidence which indicate that the calcineurin signaling pathway, a target of the immunosuppressive drugs FK506 and cyclosporine A, orchestrates growth, virulence and drug resistance in a variety of fungal pathogens and can be exploited for novel antifungal drug development.
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Affiliation(s)
- Praveen R. Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University School of Medicine, Durham, NC, USA
| | - Soo Chan Lee
- Department of Molecular Genetics & Microbiology, Duke University School of Medicine, Durham, NC, USA
| | - Joseph Heitman
- Department of Molecular Genetics & Microbiology, Duke University School of Medicine, Durham, NC, USA
- Department of Medicine, Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC, USA
| | - William J. Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University School of Medicine, Durham, NC, USA
- Department of Molecular Genetics & Microbiology, Duke University School of Medicine, Durham, NC, USA
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18
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Abstract
The antifungal "paradoxical effect" has been described as the reversal of growth inhibition at high doses of echinocandins, most usually caspofungin. This microbiological effect appears to be a cellular compensatory response to cell wall damage, resulting in alteration of cell wall content and structure as well as fungal morphology and growth. In vitro studies demonstrate this reproducible effect in a certain percentage of fungal isolates, but animal model and clinical studies are less consistent. The calcineurin and Hsp90 cell signaling pathways appear to play a major role in regulating these cellular and structural changes. Regardless of the clinical relevance of this paradoxical growth effect, understanding the specific actions of echinocandins is paramount to optimizing their use at either standard or higher dosing schemes, as well as developing future improvements in our antifungal arsenal.
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Affiliation(s)
- William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina
| | - Frédéric Lamoth
- Division of Pediatric Infectious Diseases, Department of Pediatrics Infectious Diseases Service, Department of Medicine Institute of Microbiology, Lausanne University Hospital, Switzerland
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Vargas-Muñiz JM, Juvvadi PR, Steinbach WJ. Forging the ring: from fungal septins' divergent roles in morphology, septation and virulence to factors contributing to their assembly into higher order structures. Microbiology (Reading) 2016; 162:1527-1534. [PMID: 27559018 DOI: 10.1099/mic.0.000359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Septins are a conserved family of GTP-binding proteins that are distributed across different lineages of the eukaryotes, with the exception of plants. Septins perform a myriad of functions in fungal cells, ranging from controlling morphogenetic events to contributing to host tissue invasion and virulence. One key attribute of the septins is their ability to assemble into heterooligomeric complexes that organizse into higher order structures. In addition to the established role of septins in the model budding yeast, Saccharomyces cerevisiae, their importance in other fungi recently emerges. While newer roles for septins are being uncovered in these fungi, the mechanism of how septins assemble into a complex and their regulation is only beginning to be comprehended. In this review, we summarize recent findings on the role of septins in different fungi and focus on how the septin complexes of different fungi are organized in vitro and in vivo. Furthermore, we discuss on how phosphorylation/dephosphorylation can serve as an important mechanism of septin complex assembly and regulation.
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Affiliation(s)
- Jose M Vargas-Muñiz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - William J Steinbach
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA.,Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
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20
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Vargas-Muñiz JM, Renshaw H, Richards AD, Waitt G, Soderblom EJ, Moseley MA, Asfaw Y, Juvvadi PR, Steinbach WJ. Dephosphorylation of the Core Septin, AspB, in a Protein Phosphatase 2A-Dependent Manner Impacts Its Localization and Function in the Fungal Pathogen Aspergillus fumigatus. Front Microbiol 2016; 7:997. [PMID: 27446037 PMCID: PMC4916205 DOI: 10.3389/fmicb.2016.00997] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/10/2016] [Indexed: 12/24/2022] Open
Abstract
Septins are a conserved family of GTPases that form hetero–oligomeric complexes and perform diverse functions in higher eukaryotes, excluding plants. Our previous studies in the human fungal pathogen Aspergillus fumigatus revealed that the core septin, AspB, a CDC3 ortholog, is required for septation, conidiation, and conidial cell wall organization. Although AspB is important for these cellular functions, nothing is known about the role of kinases or phosphatases in the posttranslational regulation and localization of septins in A. fumigatus. In this study, we assessed the function of the Gin4 and Cla4 kinases and the PP2A regulatory subunit ParA, in the regulation of AspB using genetic and phosphoproteomic approaches. Gene deletion analyses revealed that Cla4 and ParA are indispensable for hyphal extension, and Gin4, Cla4, and ParA are each required for conidiation and normal septation. While deletion of gin4 resulted in larger interseptal distances and hypervirulence, a phenotype mimicking aspB deletion, deletion of cla4 and parA caused hyperseptation without impacting virulence, indicating divergent roles in regulating septation. Phosphoproteomic analyses revealed that AspB is phosphorylated at five residues in the GTPase domain (S134, S137, S247, T297, and T301) and two residues at its C-terminus (S416 and S461) in the wild-type, Δgin4 and Δcla4 strains. However, concomitant with the differential localization pattern of AspB and hyperseptation in the ΔparA strain, AspB remained phosphorylated at two additional residues, T68 in the N-terminal polybasic region and S447 in the coiled-coil domain. Generation of nonphosphorylatable and phosphomimetic strains surrounding each differentially phosphorylated residue revealed that only AspBmt-T68E showed increased interseptal distances, suggesting that dephosphorylation of T68 is important for proper septation. This study highlights the importance of septin phosphorylation/dephosphorylation in the regulation of A. fumigatus hyphal septation.
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Affiliation(s)
- José M Vargas-Muñiz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC, USA
| | - Hilary Renshaw
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC, USA
| | - Amber D Richards
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham NC, USA
| | - Greg Waitt
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham NC, USA
| | - Erik J Soderblom
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham NC, USA
| | - Martin A Moseley
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University, Durham NC, USA
| | - Yohannes Asfaw
- Department of Laboratory Animal Resources, Duke University Medical Center, Durham NC, USA
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham NC, USA
| | - William J Steinbach
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, DurhamNC, USA; Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, DurhamNC, USA
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21
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Juvvadi PR, Pemble CW, Ma Y, Steinbach WJ. Novel motif in calcineurin catalytic subunit is required for septal localization of calcineurin in Aspergillus fumigatus. FEBS Lett 2016; 590:501-8. [PMID: 26864964 DOI: 10.1002/1873-3468.12075] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/01/2016] [Accepted: 01/15/2016] [Indexed: 11/06/2022]
Abstract
Calcineurin heterodimer, comprised of the catalytic (CnaA) and regulatory (CnaB) subunits, localizes at the hyphal tips and septa to direct growth, septation, and disease in the human pathogen Aspergillus fumigatus. Here we discovered a novel motif (FMDVF) required for this critical CnaA septal localization, including residues Phe368, Asp370 and Phe372 overlapping the cyclosporine A-cyclophilin A-binding domain, CnaB-binding helix and the FK506-FKBP12-binding pocket. Mutations in adjacent residues Asn367, Trp374, and Ser375 confer FK506 resistance without impacting CnaA septal localization. Modeling A. fumigatus CnaA confirmed that the FMDVF motif forms a bridge between the two known substrate-binding motifs, PxIxIT and LxVP, and concurrent mutations (F368A D370A; F368A F372A) in the FMDVF motif disrupt CnaA-substrate interaction at the septum.
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Affiliation(s)
- Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - Charles W Pemble
- Duke Macromolecular Crystallography Center, Duke University Medical Center, Durham, NC, USA
| | - Yan Ma
- Department of Dermatology and Venereology, The Second Hospital of Shanxi Medical University, Taiyuan, Shanxi, China
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA.,Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
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22
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Affiliation(s)
- Frédéric Lamoth
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical CenterDurham, NC, USA; Infectious Diseases Service, Department of Medicine, Lausanne University HospitalLausanne, Switzerland; Institute of Microbiology, Lausanne University HospitalLausanne, Switzerland
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center Durham, NC, USA
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical CenterDurham, NC, USA; Department of Molecular Genetics and Microbiology, Duke University Medical CenterDurham, NC, USA
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23
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Juvvadi PR, Steinbach WJ. Calcineurin Orchestrates Hyphal Growth, Septation, Drug Resistance and Pathogenesis of Aspergillus fumigatus: Where Do We Go from Here? Pathogens 2015; 4:883-93. [PMID: 26694470 PMCID: PMC4693169 DOI: 10.3390/pathogens4040883] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 12/07/2015] [Accepted: 12/11/2015] [Indexed: 12/27/2022] Open
Abstract
Studies on fungal pathogens belonging to the ascomycota phylum are critical given the ubiquity and frequency with which these fungi cause infections in humans. Among these species, Aspergillus fumigatus causes invasive aspergillosis, a leading cause of death in immunocompromised patients. Fundamental to A. fumigatus pathogenesis is hyphal growth. However, the precise mechanisms underlying hyphal growth and virulence are poorly understood. Over the past 10 years, our research towards the identification of molecular targets responsible for hyphal growth, drug resistance and virulence led to the elucidation of calcineurin as a key signaling molecule governing these processes. In this review, we summarize our salient findings on the significance of calcineurin for hyphal growth and septation in A. fumigatus and propose future perspectives on exploiting this pathway for designing new fungal-specific therapeutics.
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Affiliation(s)
- Praveen R Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC 27710, USA.
| | - William J Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC 27710, USA.
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC 27710, USA.
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24
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Falloon K, Juvvadi PR, Richards AD, Vargas-Muñiz JM, Renshaw H, Steinbach WJ. Characterization of the FKBP12-Encoding Genes in Aspergillus fumigatus. PLoS One 2015; 10:e0137869. [PMID: 26366742 PMCID: PMC4569257 DOI: 10.1371/journal.pone.0137869] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 08/22/2015] [Indexed: 01/11/2023] Open
Abstract
Invasive aspergillosis, largely caused by Aspergillus fumigatus, is responsible for a growing number of deaths among immunosuppressed patients. Immunosuppressants such as FK506 (tacrolimus) that target calcineurin have shown promise for antifungal drug development. FK506-binding proteins (FKBPs) form a complex with calcineurin in the presence of FK506 (FKBP12-FK506) and inhibit calcineurin activity. Research on FKBPs in fungi is limited, and none of the FKBPs have been previously characterized in A. fumigatus. We identified four orthologous genes of FKBP12, the human FK506 binding partner, in A. fumigatus and designated them fkbp12-1, fkbp12-2, fkbp12-3, and fkbp12-4. Deletional analysis of the four genes revealed that the Δfkbp12-1 strain was resistant to FK506, indicating FKBP12-1 as the key mediator of FK506-binding to calcineurin. The endogenously expressed FKBP12-1-EGFP fusion protein localized to the cytoplasm and nuclei under normal growth conditions but also to the hyphal septa following FK506 treatment, revealing its interaction with calcineurin. The FKBP12-1-EGFP fusion protein didn’t localize at the septa in the presence of FK506 in the cnaA deletion background, confirming its interaction with calcineurin. Testing of all deletion strains in the Galleria mellonella model of aspergillosis suggested that these proteins don’t play an important role in virulence. While the Δfkbp12-2 and Δfkbp12-3 strains didn’t show any discernable phenotype, the Δfkbp12-4 strain displayed slight growth defect under normal growth conditions and inhibition of the caspofungin-mediated “paradoxical growth effect” at higher concentrations of the antifungal caspofungin. Together, these results indicate that while only FKBP12-1 is the bona fide binding partner of FK506, leading to the inhibition of calcineurin in A. fumigatus, FKBP12-4 may play a role in basal growth and the caspofungin-mediated paradoxical growth response. Exploitation of differences between A. fumigatus FKBP12-1 and human FKBP12 will be critical for the generation of fungal-specific FK506 analogs to inhibit fungal calcineurin and treat invasive fungal disease.
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Affiliation(s)
- Katie Falloon
- Duke University School of Medicine, Durham, NC, United States of America
| | - Praveen R. Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
| | - Amber D. Richards
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
| | - José M. Vargas-Muñiz
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States of America
| | - Hilary Renshaw
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States of America
| | - William J. Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, NC, United States of America
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, United States of America
- * E-mail:
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25
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Juvvadi PR, Ma Y, Richards AD, Soderblom EJ, Moseley MA, Lamoth F, Steinbach WJ. Identification and mutational analyses of phosphorylation sites of the calcineurin-binding protein CbpA and the identification of domains required for calcineurin binding in Aspergillus fumigatus. Front Microbiol 2015; 6:175. [PMID: 25821446 PMCID: PMC4358225 DOI: 10.3389/fmicb.2015.00175] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/16/2015] [Indexed: 11/26/2022] Open
Abstract
Calcineurin is a key protein phosphatase required for hyphal growth and virulence in Aspergillus fumigatus, making it an attractive antifungal target. However, currently available calcineurin inhibitors, FK506 and cyclosporine A, are immunosuppressive, limiting usage in the treatment of patients with invasive aspergillosis. Therefore, the identification of endogenous inhibitors of calcineurin belonging to the calcipressin family is an important parallel strategy. We previously identified the gene cbpA as the A. fumigatus calcipressin member and showed its involvement in hyphal growth and calcium homeostasis. However, the mechanism of its activation/inhibition through phosphorylation and its interaction with calcineurin remains unknown. Here we show that A. fumigatus CbpA is phosphorylated at three distinct domains, including the conserved SP repeat motif (phosphorylated domain-I; PD-I), a filamentous fungal-specific domain (PD-II), and the C-terminal CIC motif (Calcipressin Inhibitor of Calcineurin; PD-III). While mutation of three phosphorylated residues (Ser208, Ser217, Ser223) in the PD-II did not affect CbpA function in vivo, mutation of the two phosphorylated serines (Ser156, Ser160) in the SP repeat motif caused reduced hyphal growth and sensitivity to oxidative stress. Mutational analysis in the key domains in calcineurin A (CnaA) and proteomic interaction studies confirmed the requirement of PxIxIT motif-binding residues (352-NIR-354) and the calcineurin B (CnaB)-binding helix residue (V371) for the binding of CbpA to CnaA. Additionally, while the calmodulin-binding residues (442-RVF-444) did not affect CbpA binding to CnaA, three mutations (T359P, H361L, and L365S) clustered between the CnaA catalytic and the CnaB-binding helix were also required for CbpA binding. This is the first study to analyze the phosphorylation status of calcipressin in filamentous fungi and identify the domains required for binding to calcineurin.
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Affiliation(s)
- Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center Durham, NC, USA
| | - Yan Ma
- Department of Dermatology and Venereology, The Second Hospital of Shanxi Medical University Taiyuan, Shanxi, China
| | - Amber D Richards
- Department of Dermatology and Venereology, The Second Hospital of Shanxi Medical University Taiyuan, Shanxi, China
| | - Erik J Soderblom
- Department of Dermatology and Venereology, The Second Hospital of Shanxi Medical University Taiyuan, Shanxi, China
| | - M Arthur Moseley
- Duke Proteomics and Metabolomics Core Facility, Center for Genomic and Computational Biology, Duke University Durham, NC, USA
| | - Frédéric Lamoth
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center Durham, NC, USA ; Infectious Diseases Service, Department of Medicine, Lausanne University Hospital Lausanne, Switzerland ; Institute of Microbiology, Lausanne University Hospital Lausanne, Switzerland
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center Durham, NC, USA ; Department of Molecular Genetics and Microbiology, Duke University Medical Center Durham, NC, USA
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26
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Lamoth F, Juvvadi PR, Steinbach WJ. Histone deacetylase inhibition as an alternative strategy against invasive aspergillosis. Front Microbiol 2015; 6:96. [PMID: 25762988 PMCID: PMC4329796 DOI: 10.3389/fmicb.2015.00096] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 01/26/2015] [Indexed: 01/07/2023] Open
Abstract
Invasive aspergillosis (IA) is a life-threatening infection due to Aspergillus fumigatus and other Aspergillus spp. Drugs targeting the fungal cell membrane (triazoles, amphotericin B) or cell wall (echinocandins) are currently the sole therapeutic options against IA. Their limited efficacy and the emergence of resistance warrant the identification of new antifungal targets. Histone deacetylases (HDACs) are enzymes responsible of the deacetylation of lysine residues of core histones, thus controlling chromatin remodeling and transcriptional activation. HDACs also control the acetylation and activation status of multiple non-histone proteins, including the heat shock protein 90 (Hsp90), an essential molecular chaperone for fungal virulence and antifungal resistance. This review provides an overview of the different HDACs in Aspergillus spp. as well as their respective contribution to total HDAC activity, fungal growth, stress responses, and virulence. The potential of HDAC inhibitors, currently under development for cancer therapy, as novel alternative antifungal agents against IA is discussed.
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Affiliation(s)
- Frédéric Lamoth
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center , Durham, NC, USA ; Infectious Diseases Service, Department of Medicine, Lausanne University Hospital , Lausanne, Switzerland ; Institute of Microbiology, Lausanne University Hospital , Lausanne, Switzerland
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center , Durham, NC, USA
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center , Durham, NC, USA ; Department of Molecular Genetics and Microbiology, Duke University Medical Center , Durham, NC, USA
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27
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Lamoth F, Alexander BD, Juvvadi PR, Steinbach WJ. Antifungal activity of compounds targeting the Hsp90-calcineurin pathway against various mould species. J Antimicrob Chemother 2015; 70:1408-11. [PMID: 25558076 DOI: 10.1093/jac/dku549] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 12/09/2014] [Indexed: 01/02/2023] Open
Abstract
OBJECTIVES Invasive mould infections are associated with a high mortality rate and the emergence of MDR moulds is of particular concern. Calcineurin and its chaperone, the heat shock protein 90 (Hsp90), represent an important pathway for fungal virulence that can be targeted at different levels. We investigated the antifungal activity of compounds directly or indirectly targeting the Hsp90-calcineurin axis against different mould species. METHODS The in vitro antifungal activity of the anticalcineurin drug FK506 (tacrolimus), the Hsp90 inhibitor geldanamycin, the lysine deacetylase inhibitor trichostatin A and the Hsp70 inhibitor pifithrin-μ was assessed by the standard broth dilution method against 62 clinical isolates of Aspergillus spp. and non-Aspergillus moulds (Mucoromycotina, Fusarium spp., Scedosporium spp., Purpureocillium/Paecilomyces spp. and Scopulariopsis spp.) RESULTS FK506 had variable antifungal activity against different Aspergillus spp. and was particularly active against Mucor spp. Geldanamycin had moderate antifungal activity against Fusarium spp. and Paecilomyces variotii. Importantly, trichostatin A had good activity against the triazole-resistant Aspergillus ustus and the amphotericin B-resistant Aspergillus terreus as well as the MDR Scedosporium prolificans. Moreover, trichostatin A exhibited synergistic interactions with caspofungin against A. ustus and with geldanamycin against Rhizopus spp. for which none of the other agents showed activity. Pifithrin-μ exhibited little antifungal activity. CONCLUSIONS Targeting the Hsp90-calcineurin axis at different levels resulted in distinct patterns of susceptibility among different fungal species. Lysine deacetylase inhibition may represent a promising novel antifungal strategy against emerging resistant moulds.
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Affiliation(s)
- Frédéric Lamoth
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University Medical Center, Durham, NC, USA Clinical Microbiology Laboratory, Department of Pathology, Duke University Medical Center, Durham, NC, USA Service of Infectious Diseases, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland
| | - Barbara D Alexander
- Division of Infectious Diseases and International Health, Department of Medicine, Duke University Medical Center, Durham, NC, USA Clinical Microbiology Laboratory, Department of Pathology, Duke University Medical Center, Durham, NC, USA
| | - Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA
| | - William J Steinbach
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, Durham, NC, USA Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
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Abstract
The genus Aspergillus contains etiologic agents of aspergillosis. The clinical manifestations of the disease range from allergic reaction to invasive pulmonary infection. Among the pathogenic aspergilli, Aspergillus fumigatus is most ubiquitous in the environment and is the major cause of the disease, followed by Aspergillus flavus, Aspergillus niger, Aspergillus terreus, Aspergillus nidulans, and several species in the section Fumigati that morphologically resemble A. fumigatus. Patients that are at risk for acquiring aspergillosis are those with an altered immune system. Early diagnosis, species identification, and adequate antifungal therapy are key elements for treatment of the disease, especially in cases of pulmonary invasive aspergillosis that often advance very rapidly. Incorporating knowledge of the basic biology of Aspergillus species to that of the diseases that they cause is fundamental for further progress in the field.
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Affiliation(s)
- Janyce A Sugui
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Kyung J Kwon-Chung
- Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Praveen R Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University, Durham, North Carolina 27715
| | - Jean-Paul Latgé
- Unité des Aspergillus, Institut Pasteur, Paris 75724, France
| | - William J Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University, Durham, North Carolina 27715 Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina 27710
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29
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Juvvadi PR, Lamoth F, Steinbach WJ. Calcineurin as a Multifunctional Regulator: Unraveling Novel Functions in Fungal Stress Responses, Hyphal Growth, Drug Resistance, and Pathogenesis. FUNGAL BIOL REV 2014; 28:56-69. [PMID: 25383089 DOI: 10.1016/j.fbr.2014.02.004] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Calcineurin signaling plays diverse roles in fungi in regulating stress responses, morphogenesis and pathogenesis. Although calcineurin signaling is conserved among fungi, recent studies indicate important divergences in calcineurin-dependent cellular functions among different human fungal pathogens. Fungal pathogens utilize the calcineurin pathway to effectively survive the host environment and cause life-threatening infections. The immunosuppressive calcineurin inhibitors (FK506 and cyclosporine A) are active against fungi, making targeting calcineurin a promising antifungal drug development strategy. Here we summarize current knowledge on calcineurin in yeasts and filamentous fungi, and review the importance of understanding fungal-specific attributes of calcineurin to decipher fungal pathogenesis and develop novel antifungal therapeutic approaches.
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Affiliation(s)
- Praveen R Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA
| | - Frédéric Lamoth
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA ; Infectious Diseases Service, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland ; Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland
| | - William J Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA ; Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC, USA
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30
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Abstract
Invasive aspergillosis is a life-threatening and difficult to treat infection in immunosuppressed patients. The efficacy of current anti-Aspergillus therapies, targeting the cell wall or membrane, is limited by toxicity (polyenes), fungistatic activity and some level of basal resistance (echinocandins), or the emergence of acquired resistance (triazoles). The heat shock protein 90 (Hsp90) is a conserved molecular chaperone involved in the rapid development of antifungal resistance in the yeast Candida albicans. Few studies have addressed its role in filamentous fungi such as Aspergillus fumigatus, in which mechanisms of resistance may differ substantially. Hsp90 is at the center of a complex network involving calcineurin, lysine deacetylases (KDAC) and other client proteins, which orchestrate compensatory repair mechanisms of the cell wall in response to the stress induced by antifungals. In A. fumigatus, Hsp90 is a trigger for resistance to high concentrations of caspofungin, known as the paradoxical effect. Disrupting Hsp90 circuitry by different means (Hsp90 inhibitors, KDAC inhibitors and anti-calcineurin drugs) potentiates the antifungal activity of caspofungin, thus representing a promising novel antifungal approach. This review will discuss the specific features of A. fumigatus Hsp90 and the potential for antifungal strategies of invasive aspergillosis targeting this essential chaperone.
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Affiliation(s)
- Frédéric Lamoth
- a Division of Pediatric Infectious Diseases, Department of Pediatrics , Duke University Medical Center , Durham , NC , USA .,b Infectious Diseases Service, Department of Medicine , Lausanne University Hospital , Lausanne , Switzerland .,c Institute of Microbiology, Lausanne University Hospital , Lausanne , Switzerland , and
| | - Praveen R Juvvadi
- a Division of Pediatric Infectious Diseases, Department of Pediatrics , Duke University Medical Center , Durham , NC , USA
| | - William J Steinbach
- a Division of Pediatric Infectious Diseases, Department of Pediatrics , Duke University Medical Center , Durham , NC , USA .,d Department of Molecular Genetics and Microbiology , Duke University Medical Center , Durham , NC , USA
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Juvvadi PR, Lamoth F, Steinbach WJ. Calcineurin-mediated regulation of hyphal growth, septation, and virulence in Aspergillus fumigatus. Mycopathologia 2014; 178:341-8. [PMID: 25118871 DOI: 10.1007/s11046-014-9794-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 07/31/2014] [Indexed: 01/26/2023]
Abstract
Calcineurin is a heterodimeric protein phosphatase complex composed of catalytic (CnaA) and regulatory (CnaB) subunits and plays diverse roles in regulating fungal stress responses, morphogenesis, and pathogenesis. Fungal pathogens utilize the calcineurin pathway to survive in the host environment and cause life-threatening infections. The immunosuppressive calcineurin inhibitors (FK506 and cyclosporine A) are active against fungi, making calcineurin a promising antifungal drug target. Here, we review novel findings on calcineurin localization and functions in Aspergillus fumigatus hyphal growth and septum formation through regulation of proteins involved in cell wall biosynthesis. Extensive mutational analysis in the functional domains of A. fumigatus CnaA has led to an understanding of the relevance of these domains for the localization and function of CnaA at the hyphal septum. An evolutionarily conserved novel mode of calcineurin regulation by phosphorylation in filamentous fungi was found to be responsible for virulence in A. fumigatus. This finding of a filamentous fungal-specific mechanism controlling hyphal growth and virulence represents a potential target for antifungal therapy.
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Affiliation(s)
- Praveen R Juvvadi
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Duke University Medical Center, 427 Jones Building, Research Drive, Durham, NC, 27710, USA,
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Lamoth F, Juvvadi PR, Gehrke C, Asfaw YG, Steinbach WJ. Transcriptional activation of heat shock protein 90 mediated via a proximal promoter region as trigger of caspofungin resistance in Aspergillus fumigatus. J Infect Dis 2013; 209:473-81. [PMID: 24096332 DOI: 10.1093/infdis/jit530] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Invasive aspergillosis is a deadly infection for which new antifungal therapies are needed. Heat shock protein 90 (Hsp90) is an essential chaperone in Aspergillus fumigatus representing an attractive antifungal target. Using a thiamine-repressible promoter (pthiA), we showed that genetic repression of Hsp90 significantly reduced virulence in a murine model of invasive aspergillosis. Moreover, substituting the A. fumigatus hsp90 promoter with 2 artificial promoters (potef, pthiA) and the Candida albicans hsp90 promoter resulted in hypersensitivity to caspofungin and abolition of the paradoxical effect (resistance at high caspofungin concentrations). By inducing truncations in the hsp90 promoter, we identified a 100-base pair proximal sequence that triggers a significant increase of hsp90 expression (≥1.5-fold) and is essential for the paradoxical effect. Preventing this increase of hsp90 expression was sufficient to abolish the paradoxical effect and therefore optimize the antifungal activity of caspofungin.
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Affiliation(s)
- Frédéric Lamoth
- Division of Pediatric Infectious Diseases, Department of Pediatrics
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Juvvadi PR, Gehrke C, Fortwendel JR, Lamoth F, Soderblom EJ, Cook EC, Hast MA, Asfaw YG, Moseley MA, Creamer TP, Steinbach WJ. Phosphorylation of Calcineurin at a novel serine-proline rich region orchestrates hyphal growth and virulence in Aspergillus fumigatus. PLoS Pathog 2013; 9:e1003564. [PMID: 23990785 PMCID: PMC3749960 DOI: 10.1371/journal.ppat.1003564] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Accepted: 07/02/2013] [Indexed: 12/26/2022] Open
Abstract
The fungus Aspergillus fumigatus is a leading infectious killer in immunocompromised patients. Calcineurin, a calmodulin (CaM)-dependent protein phosphatase comprised of calcineurin A (CnaA) and calcineurin B (CnaB) subunits, localizes at the hyphal tips and septa to direct A. fumigatus invasion and virulence. Here we identified a novel serine-proline rich region (SPRR) located between two conserved CnaA domains, the CnaB-binding helix and the CaM-binding domain, that is evolutionarily conserved and unique to filamentous fungi and also completely absent in human calcineurin. Phosphopeptide enrichment and tandem mass spectrometry revealed the phosphorylation of A. fumigatus CnaA in vivo at four clustered serine residues (S406, S408, S410 and S413) in the SPRR. Mutation of the SPRR serine residues to block phosphorylation led to significant hyphal growth and virulence defects, indicating the requirement of calcineurin phosphorylation at the SPRR for its activity and function. Complementation analyses of the A. fumigatus ΔcnaA strain with cnaA homologs from the pathogenic basidiomycete Cryptococcus neoformans, the pathogenic zygomycete Mucor circinelloides, the closely related filamentous fungi Neurospora crassa, and the plant pathogen Magnaporthe grisea, revealed filamentous fungal-specific phosphorylation of CnaA in the SPRR and SPRR homology-dependent restoration of hyphal growth. Surprisingly, circular dichroism studies revealed that, despite proximity to the CaM-binding domain of CnaA, phosphorylation of the SPRR does not alter protein folding following CaM binding. Furthermore, mutational analyses in the catalytic domain, CnaB-binding helix, and the CaM-binding domains revealed that while the conserved PxIxIT substrate binding motif in CnaA is indispensable for septal localization, CaM is required for its function at the hyphal septum but not for septal localization. We defined an evolutionarily conserved novel mode of calcineurin regulation by phosphorylation in filamentous fungi in a region absent in humans. These findings suggest the possibility of harnessing this unique SPRR for innovative antifungal drug design to combat invasive aspergillosis.
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Affiliation(s)
- Praveen R. Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Christopher Gehrke
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Jarrod R. Fortwendel
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Frédéric Lamoth
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Erik J. Soderblom
- Duke Proteomics Facility, Institute for Genome Sciences and Policy, Duke University, Durham, North Carolina, United States of America
| | - Erik C. Cook
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, Kentucky, United States of America
| | - Michael A. Hast
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Yohannes G. Asfaw
- Division of Laboratory Animal Resources, Duke University Medical Center, Durham, North Carolina, United States of America
| | - M. Arthur Moseley
- Duke Proteomics Facility, Institute for Genome Sciences and Policy, Duke University, Durham, North Carolina, United States of America
| | - Trevor P. Creamer
- Department of Molecular and Cellular Biochemistry and Center for Structural Biology, University of Kentucky, Lexington, Kentucky, United States of America
| | - William J. Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina, United States of America
- * E-mail:
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Abstract
The fungal cell wall represents an attractive target for pharmacologic inhibition, as many of the components are fungal-specific. Though targeted inhibition of β-glucan synthesis is effective treatment for certain fungal infections, the ability of the cell wall to dynamically compensate via the cell wall integrity pathway may limit overall efficacy. To date, chitin synthesis inhibitors have not been successfully deployed in the clinical setting. Fungal chitin synthesis is a complex and highly regulated process. Regulation of chitin synthesis occurs on multiple levels, thus targeting of these regulatory pathways may represent an exciting alternative approach. A variety of signaling pathways have been implicated in chitin synthase regulation, at both transcriptional and post-transcriptional levels. Recent research suggests that localization of chitin synthases likely represents a major regulatory mechanism. However, much of the regulatory machinery is not necessarily shared among different chitin synthases. Thus, an in-depth understanding of the precise roles of each protein in cell wall maintenance and repair will be essential to identifying the most likely therapeutic targets.
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Affiliation(s)
- Luise E. Rogg
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA
| | - Jarrod R. Fortwendel
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC, USA
| | - Praveen R. Juvvadi
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA
| | - William J. Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University Medical Center, Durham NC, USA
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham NC, USA
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Abstract
Optimal therapy for invasive aspergillosis is unknown, and many clinicians have attempted to utilize a combination antifungal approach to improve outcomes. However, while numerous in vitro studies, animal models, and clinical reports suggest the possibility that combination antifungal therapy might offer improved results, there is no definitive accepted strategy. The currently available antifungals used in various combination approaches have not demonstrated clear improvement over monotherapy. The current classes of drugs targeting the cell wall and cell membrane may need adjunctive agents focused on separate cellular pathways, such as cell stress response or cellular signaling, to maximize efficacy. The calcineurin and the Hsp90 pathways are two such untouched arenas in which targeted manipulation may lead to great advances against aspergillosis.
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Affiliation(s)
- William J Steinbach
- Department of Pediatrics, Division of Pediatric Infectious Diseases, Duke University, Durham, NC 27710, USA.
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Juvvadi PR, Arioka M, Nakajima H, Kitamoto K. Cloning and sequence analysis of cnaA gene encoding the catalytic subunit of calcineurin from Aspergillus oryzae. FEMS Microbiol Lett 2001; 204:169-74. [PMID: 11682197 DOI: 10.1111/j.1574-6968.2001.tb10881.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Calcineurin has been implicated in ion-homeostasis, stress adaptation in yeast and for hyphal growth in filamentous fungi. Genomic DNA and cDNA encoding the catalytic subunit of calcineurin (cnaA) were isolated from Aspergillus oryzae. The cnaA open reading frame extended to 1727 bp and encoded a putative protein of 514 amino acids. Comparative analysis of the nucleotide sequence of cnaA genomic DNA and cDNA confirmed the presence of three introns and a highly conserved calmodulin binding domain. The deduced amino acid sequence was homologous to calcineurin A from Aspergillus nidulans (92%), Neurospora crassa (84%), human (67%), Saccharomyces cerevisiae (58%) and Schizosaccharomyces pombe (54%). Further, A. oryzae cnaA cDNA complemented S. cerevisiae calcineurin disruptant strain (Deltacmp1 Deltacmp2), which was not viable in the presence of high concentrations of NaCl (1.2 M) and at alkaline pH 8.5.
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Affiliation(s)
- P R Juvvadi
- Department of Biotechnology, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-Ku, 113-8657 Tokyo, Japan
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