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Investigación
Adaptation of pathogenic fungi to the host and development of new antifungal therapies
Líneas de investigación
Content with Investigacion .
Mechanisms of pathogenic fungal host adaptation: Morphogenesis in Cryptococcus neoformans
One of the main mechanisms by which fungi are able to cause disease in humans is their ability to evade the immune response and adapt to the environmental conditions found in the host. In this regard, one of the yeasts that has the greatest ability to adapt to the host is Cryptococcus neoformans. This fungus is found in the environment, and is acquired by inhalation, although the most typical picture is meningitis in immunocompromised patients, mainly HIV+. The main phenotypic characteristic is the presence of a polysaccharide capsule surrounding the cell, which is considered a virulence factor. In addition, C. neoformans is able to increase cell size significantly forming “titan” cells, which can reach a diameter of more than 70 microns. In the laboratory, we are interested in the role of these titan cells in the virulence of C. neoformans. Recently, we have described in vitro media in which C. neoformans forms pseudo-titan cells, which has allowed us to identify new factors and pathways involved in this process.
Mechanisms of action of antifungals
In parallel, we have a line whose main objective is to characterize the mechanisms of action of antifungals. Specifically, we have focused our work on the effect of Amphotericin B (AmB). For decades it has been thought that this antifungal causes cell death after binding to ergosterol and pore formation. Our results indicate that this antifungal also induces strong oxidative stress in the cell, which occurs before cell integrity is lost. Furthermore, we have shown that oxidative stress is necessary for the fungicidal action of AmB. These results open the door to design new strategies to improve its efficiency in patients.
New therapeutic strategies
Work with AmB has led to research aimed at improving antifungal therapies. In particular, we have used the strategy of “off-patent” drug repositioning to search for new activities. Using this approach, we have identified several drugs that increase the effectiveness of AmB against major pathogenic yeasts, such as the antibiotic erythromycin. This approach has allowed us to identify drugs with antifungal activity against emerging pathogens, such as Candida auris.
Proyectos de investigación
Content with Investigacion .
Projects with public funding
TITLE: Virulence factors of pathogenic yeasts and their influence on the host.
FUNDING ENTITY: Ministry of Education and Science.
POSITION HELD: Principal Investigator, Contracted “Ramón y Cajal”.
START/FINISH: 2006-2007
AMOUNT: 15,000 EUROS
TITLE: Characterization of fungal giant cells and their role during infection in mammals.
FINANCING ENTITY: Instituto de Salud Carlos III
POSITION HELD: Principal Investigator, Contracted “Ramón y Cajal”.
START/FINISH: 2006-2007
AMOUNT: 55,000 EUROS
TITLE: Search and identification of genes involved in the resistance to antifungal agents in
Cryptococcus neoformans
FUNDING ENTITY: Ministry of Science and Innovation.
POSITION HELD: Principal Investigator, Contracted “Ramón y Cajal”.
START/FINISH: 2008-2010
AMOUNT: 25,000 EUROS
COLLABORATORS: Juan Luis Rodríguez Tudela (National Center of Microbiology, ISCIII. Madrid); Manuel Cuenca Estrella (National Center of Microbiology, ISCIII. Madrid); Maria Jose Gianinni (Faculdade de Ciências Farmacêuticas-UNESP). Brazil
TITLE: Role of morphological changes of the pathogenic yeast Cryptococcus neoformans during host infection.
FUNDING ENTITY: Ministry of Science and Innovation. National Plan Program “Non-oriented Fundamental Research”, area of Biomedicine, SAF2008-03761.
POSITION HELD: Principal Investigator, Contracted “Ramón y Cajal”.
START/END: 2009-2011
AMOUNT: 46,000 EUROS
PROJECT TITLE: Identification of the molecular mechanisms involved in the morphogenesis of Cryptococcus neoformans and study of their function during infection.
FUNDING ENTITY: Ministry of Science and Innovation, National Plan for Non-Oriented Fundamental Research, Biomedicine Area, Referencia: SAF2011-25140
DURATION FROM: January 2012 UNTIL: December 2014
PRINCIPAL INVESTIGATOR: Oscar Zaragoza Hernández
This project has an FPI grantee granted.
SUBSIDY: 90.000 euros
TITLE: Importance of morphogenesis in the virulence of pathogenic yeast Cryptococcus neoformans and improvement of amphotericin B-based cryptococcosis therapy. Reference: SAF2014-25140
FUNDING ENTITY: MINECO (Call for R+D+I Projects “RETOS INVESTIGACION)
POSITION HELD: Principal Investigator
START/FINISH: 2015-2017
Funding: 100.000 €.
TITLE: Study of the molecular basis and factors inducing morphological changes in Cryptococcus neoformans and characterization of new therapeutic strategies. Reference: SAF2017-86912-R
FUNDING ENTITY: MINECO (Call for R+D+I Projects “RETOS INVESTIGACION)
POSITION HELD: Principal Investigator
START/END: 2018-2020
Funding: 106.000 €.
TITLE: Mechanisms of adaptation of the pathogenic yeast Cryptococcus neoformans to the lung. Reference: PID2020-114546RB
FUNDING ENTITY: Ministry of Science and Innovation, State Research Agency (Call “Proyectos I+D+I” 2020 - Modalities “Research Challenges” and “Knowledge Generation”).
POSITION HELD: Principal Researcher
START/END: 2021-2024
Funding: 117,000 €.
TITLE: Precision medicine against antimicrobial resistance. MePRAM Project.
FUNDING ENTITY: Research Projects on Precision Personalized Medicine of the Strategic Action in Health 2021-2023, under the PERTE for Vanguard Health and charged to the European funds of the Recovery, Transformation and Resilience Plan.
POSITION: Collaborator (Principal Investigator: Jesús Oteo Iglesias)
START/FINISH: 2023-2025
Funding: 4.339.500 €.
TITLE: Centre for Biomedical Research in Network. Infectious Diseases Area (CIBERINFEC)
Funding Agency: Insituto de Salud Carlos III. Reference: CB21/13/00105
Dates: 2022-2026 Funding: 85.000 € (first year)
PI: Emilia Mellado Terrado / CoPI: Óscar Zaragoza Hernández
TITLE: Study of the genetic, metabolic and cellular determinants that influence titan cell formation in the fungal pathogen Cryptococcus neoformans and correlation with antifungal exposure.
CALL FOR PROJECTS: Knowledge Generation Projects.
FUNDING ENTITY. State Research Agency. Ministry of Science, Innovation and Universities.
REFERENCE: Project PID2023-148686OB-I00 Project funded by MICIU/AEI/10.13039/501100011033 and by FEDER, EU.
PRINCIPAL INVESTIGATOR: Oscar Zaragoza Hernández
START/END: 2024-2027
FUNDING: 180.000 €.
TITLE: Characterization of azole-resistant Candida parapsilosis isolates associated with hospital outbreaks: New strategies for their detection and treatment.
CALL: Strategic Action in Intramural Health.
FUNDING ENTITY. Carlos III Health Institute.
REFERENCE: AESI-2024 PI24CIII/00051
PRINCIPAL RESEARCHER: Oscar Zaragoza Hernández / Laura Alcázar Fuoli
START/FINISH: /01/012025-31/12/2027
FUNDING: 70.000 €.
Projects financed by biotechnology companies
PROJECT TITLE: Amphores. Evaluation of the induction of oxidative damage by Amphoterin B in susceptible and resistant yeast species.
FUNDING ENTITY: Gilead
DURATION FROM: 2011 TO: 2012
PRINCIPAL INVESTIGATOR: Oscar Zaragoza Hernández
GRANT: 55,000 euros
TITLE: Fungomics. Evaluation of the activity of amphotericin B and other antifungals against human pathogenic fungi.
FINANCING ENTITY: Gilead
POSITION HELD: Principal Investigator
START/END: 2019-2020
TITLE: Antifungal susceptibility testing of a set of Candida spp to CD101 and anidulafungin in five microdilution plates.
FUNDING ENTITY: Cidara
POSITION HELD: Principal Investigator
START/END: 2018
TITLE: Cidara MultiCentre EUCAST study
FUNDING ENTITY: Cidara
POSITION HELD: Principal Investigator
START/END: 2016
TITLE: Characterization of triazole-resistant Candida parapsilosis isolates from Spanish hospitals
FUNDING ENTITY: Gilead Science
POSITION HELD: Principal Investigator
START/END: 2022-2023
TITLE: EUCAST multicentre MIC testing of manogepix meeting EUCAST ECOFF setting criteria
FUNDING ENTITY: Pfizer
POSITION HELD: Principal Investigator
START/END: 2023
Publicaciones destacadas
Peptidoglycan recycling contributes to intrinsic resistance to fosfomycin in Acinetobacter baumannii
Peptidoglycan recycling contributes to intrinsic resistance to fosfomycin in Acinetobacter baumannii. Gil-Marqués ML, Moreno-Martínez P, Costas C, Pachón J, Blázquez J, McConnell MJ. J Antimicrob Chemother. 2018 Nov 1;73(11):2960-2968. doi: 10.1093/jac/dky289.
PUBMEDImmunization with lipopolysaccharide-free outer membrane complexes protects against Acinetobacter baumannii infection
Immunization with lipopolysaccharide-free outer membrane complexes protects against Acinetobacter baumannii infection. Pulido MR, García-Quintanilla M, Pachón J, McConnell MJ. Vaccine. 2018 Jul 5;36(29):4153-4156. doi: 10.1016/j.vaccine.2018.05.113.
PUBMEDPhenotypic changes associated with Colistin resistance due to Lipopolysaccharide loss in Acinetobacter baumannii
Phenotypic changes associated with Colistin resistance due to Lipopolysaccharide loss in Acinetobacter baumannii. Carretero-Ledesma M, García-Quintanilla M, Martín-Peña R, Pulido MR, Pachón J, McConnell MJ. Virulence. 2018 Dec 31;9(1):930-942. doi: 10.1080/21505594.2018.1460187.
PUBMEDInhibition of LpxC Increases Antibiotic Susceptibility in Acinetobacter baumannii
Inhibition of LpxC Increases Antibiotic Susceptibility in Acinetobacter baumannii. García-Quintanilla M, Caro-Vega JM, Pulido MR, Moreno-Martínez P, Pachón J, McConnell MJ. Antimicrob Agents Chemother. 2016 Jul 22;60(8):5076-9. doi: 10.1128/AAC.00407-16.
PUBMEDNew Panfungal Real-Time PCR Assay for Diagnosis of Invasive Fungal Infections.
4. Valero C, de la Cruz-Villar L, Zaragoza O, Buitrago MJ. New Panfungal Real-Time PCR Assay for Diagnosis of Invasive Fungal Infections. J Clin Microbiol. 2016 Dec;54(12):2910-2918. doi: 10.1128/JCM.01580-16. Epub 2016 Sep 14. PMID: 27629898.
DOIA Multiplex Real-Time PCR Assay for Identification of Pneumocystis jirovecii, Histoplasma capsulatum, and Cryptococcus neoformans/Cryptococcus gattii in Samples from AIDS Patients with Opportunistic Pneumonia
6. Gago S, Esteban C, Valero C, Zaragoza O, Puig de la Bellacasa J, Buitrago MJ. A multiplex real-time PCR assay for identification of Pneumocystis jirovecii, Histoplasma capsulatum, and Cryptococcus neoformans/Cryptococcus gattii in samples from AIDS patients with opportunistic pneumonia. J Clin Microbiol. 2014 Apr;52(4):1168-76. doi: 10.1128/JCM.02895-13. Epub 2014 Jan 29. PMID: 24478409.
PUBMED DOIAnalysis of strain relatedness using High Resolution Melting in a case of recurrent candiduria
7. Gago S, Lorenzo B, Gomez-Lopez A, Cuesta I, Cuenca-Estrella M, Buitrago MJ. Analysis of strain relatedness using high resolution melting in a case of recurrent candiduria. BMC Microbiol. 2013 Jan 23;13:13. doi: 10.1186/1471-2180-13-13. PMID: 23343107.
PUBMED DOIHigh-Resolution Melting Analysis for Identification of the Cryptococcus neoformans-Cryptococcus gattii Complex
8. Gago S, Zaragoza Ó, Cuesta I, Rodríguez-Tudela JL, Cuenca-Estrella M, Buitrago MJ. High-resolution melting analysis for identification of the Cryptococcus neoformans-Cryptococcus gattii complex. J Clin Microbiol. 2011 Oct;49(10):3663-6. doi: 10.1128/JCM.01091-11. Epub 2011 Aug 10. PMID: 21832024.
PUBMED DOIPerformance of Panfungal- and Specific-PCR-Based Procedures for Etiological Diagnosis of Invasive Fungal Diseases on Tissue Biopsy Specimens with Proven Infection: a 7-Year Retrospective Analysis from a Reference Laboratory
9. Buitrago MJ, Bernal-Martinez L, Castelli MV, Rodriguez-Tudela JL, Cuenca-Estrella M Performance of panfungal--and specific-PCR-based procedures for etiological diagnosis of invasive fungal diseases on tissue biopsy specimens with proven infection: a 7-year retrospective analysis from a reference laboratory. J Clin Microbiol. 2014 May;52(5):1737-40. doi: 10.1128/JCM.00328-14. Epub 2014 Feb 26.PMID: 24574295.
PUBMED DOIEpidemiología actual y diagnóstico de laboratorio de las micosis endémicas en España
11. Buitrago MJ, Cuenca-Estrella M. [Current epidemiology and laboratory diagnosis of endemic mycoses in Spain]. Enferm Infecc Microbiol Clin. 2012 Aug;30(7):407-13. doi: 10.1016/j.eimc.2011.09.014. Epub 2011 Nov 29. PMID: 22130575 Review. Spanish.
PUBMED DOIA matrix-assisted laser desorption/ionization time of flight mass spectrometry reference database for the identification of Histoplasma capsulatum
12. Buitrago MJ, Bernal-Martínez L, Castelli MV, Rodríguez-Tudela JL, Cuenca-Estrella M. Histoplasmosis and paracoccidioidomycosis in a non-endemic area: a review of cases and diagnosis. J Travel Med. 2011 Jan-Feb;18(1):26-33. doi: 10.1111/j.1708-8305.2010.00477.x. Epub 2010 Nov 28. PMID: 21199139.
PUBMED DOICopy Number Variation of Mitochondrial DNA Genes in Pneumocystis jirovecii According to the Fungal Load in BAL Specimens
13. Valero C, Buitrago MJ, Gago S, Quiles-Melero I, García-Rodríguez J. A matrix-assisted laser desorption/ionization time of flight mass spectrometry reference database for the identification of Histoplasma capsulatum. Med Mycol. 2018 Apr 1;56 (3):307-314. doi: 10.1093/mmy/myx047. PMID: 28992262.
PUBMED DOICopy Number Variation of Mitochondrial DNA Genes in Pneumocystis jirovecii According to the Fungal Load in BAL Specimens
14. Valero C, Buitrago MJ, Gits-Muselli M, Benazra M, Sturny-Leclère A, Hamane S, Guigue N, Bretagne S, Alanio A. Copy Number Variation of Mitochondrial DNA Genes in Pneumocystis jirovecii According to the Fungal Load in BAL Specimens. Front Microbiol. 2016 Sep 12;7:1413. doi: 10.3389/fmicb.2016.01413. eCollection 2016. PMID: 27672381.
PUBMED DOIIdentification of Off-Patent Compounds That Present Antifungal Activity Against the Emerging Fungal Pathogen Candida auris
2: de Oliveira HC, Monteiro MC, Rossi SA, Pemán J, Ruiz-Gaitán A, Mendes- Giannini MJS, Mellado E, Zaragoza O. Identification of Off-Patent Compounds That Present Antifungal Activity Against the Emerging Fungal Pathogen Candida auris. Front Cell Infect Microbiol. 2019 Apr 2;9:83. PMCID: PMC6454888.
PUBMED DOICryptococcus neoformans can form titan-like cells in vitro in response to multiple signals
Trevijano-Contador N, de Oliveira HC, García-Rodas R, Rossi SA, Llorente I, Zaballos Á, Janbon G, Ariño J, Zaragoza Ó. Cryptococcus neoformans can form titan-like cells in vitro in response to multiple signals. PLoS Pathog. 2018 May 18;14(5):e1007007. PMCID: PMC6454888.
PUBMED DOICell Wall Changes in Amphotericin B-Resistant Strains from Candida tropicalis and Relationship with the Immune Responses Elicited by the Host
5: Mesa-Arango AC, Rueda C, Román E, Quintin J, Terrón MC, Luque D, Netea MG, Pla J, Zaragoza O. Cell Wall Changes in Amphotericin B-Resistant Strains from Candida tropicalis and Relationship with the Immune Responses Elicited by the Host. Antimicrob Agents Chemother. 2016 Mar 25;60(4):2326-35. PMCID: PMC4808153.
PUBMED DOIThe production of reactive oxygen species is a universal action mechanism of Amphotericin B against pathogenic yeasts and contributes to the fungicidal effect of this drug
8: Mesa-Arango AC, Trevijano-Contador N, Román E, Sánchez-Fresneda R, Casas C, Herrero E, Argüelles JC, Pla J, Cuenca-Estrella M, Zaragoza O. The production of reactive oxygen species is a universal action mechanism of Amphotericin B against pathogenic yeasts and contributes to the fungicidal effect of this drug. Antimicrob Agents Chemother. 2014 Nov;58(11):6627-38. PMCID: PMC4249417.
PUBMED DOICapsule Growth in Cryptococcus neoformans Is Coordinated with Cell Cycle Progression
9: García-Rodas R, Cordero RJ, Trevijano-Contador N, Janbon G, Moyrand F, Casadevall A, Zaragoza O. Capsule growth in Cryptococcus neoformans is coordinated with cell cycle progression. mBio. 2014 Jun 17;5(3):e00945-14. PMCID: PMC4056547.
PUBMED DOIThe interaction between Candida krusei and murine macrophages results in multiple outcomes, including intracellular survival and escape from killing
12: García-Rodas R, González-Camacho F, Rodríguez-Tudela JL, Cuenca-Estrella M, Zaragoza O. The interaction between Candida krusei and murine macrophages results in multiple outcomes, including intracellular survival and escape from killing. Infect Immun. 2011 Jun;79(6):2136-44. PMCID: PMC3125833.
PUBMED DOIContent with Investigacion .
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Óscar Zaragoza Hernández
Research Professor
ORCID code: 0000-0002-1581-0845
Dr. Oscar Zaragoza graduated in Biology from the Complutense University of Madrid in 1995 and obtained his PhD from the Autonomous University of Madrid. He completed his doctoral thesis (2000) at the CSIC under the direction of Dr. Juana María Gancedo on the topic of glucose catabolite repression in Saccharomyces cerevisiae. During this period, he was also tutored by Dr. Carlos Gancedo in collaborative projects, that allowed him to start working with the pathogenic yeast Candida albicans.
After a brief postdoctoral stay in the same laboratory, in 2001, he joined the laboratory of Dr. Arturo Casadevall (Albert Einstein College of Medicine, New York), where he specialized in research into virulence mechanisms of pathogenic fungi, mainly Cryptococcus neoformans. In 2006 he joined the National Center for Microbiology of the ISCIII thanks to a “Ramón y Cajal” contract and he became staff scientist in 2009. Currently, he occupies the rank of Research Professor of the OPIs.
During his career, he has published more than 140 articles, 4 book chapters and a popular book ("Microscopic fungi: Friends or Enemies?"). He has obtained public and private projects, and participates as CoIP of a CIBERINFEC group. He has supervised seven doctoral theses, and numerous master's thesis projects.
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Alba Torres Cano
PhD student (FPI contract)
ORCID code: 0009-0008-3151-1803
Alba Torres Cano has a degree in Health Biology from the University of Alcalá de Henares (UAH), and completed the master's degree "Microbiology Applied to Public Health and Infectious Diseases" from the UAH. He completed his master's thesis at the CNM under the direction of Dr. Zaragoza in 2022, focusing on pathogenic yeasts. In that year, he joined the ISCIII with an FPI predoctoral contract under the direction of Dr. Óscar Zaragoza.
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Alejandra Lora Plaza
PhD student (FPI contract)
ORCID code: 0009-0004-4344-1583
Alejandra Lora Plaza graduated in Health Biology and completed the Master in Applied Microbiology in Public Health and Infectious Diseases Research (2021) at the University of Alcalá in both cases. She joined the Department of Microbiology of the Faculty of Biology of the University of Barcelona to carry out her internship and her final degree work. Subsequently, she did her Master's thesis at the Microbiology Laboratory of the Hospital Universitario Príncipe de Asturias. In 2022 she joined the Public Health and Epidemiology group at the Marqués de Valdecilla Research Institute (IDIVAL), Santander, as a research support technician. In 2024 he joined Dr. Concha Gil's group in the Department of Microbiology and Parasitology at the Faculty of Pharmacy of the Complutense University of Madrid focusing on yeasts.
In 2025 she joined ISCIII with a predoctoral FPI fellowship under the direction of Dr. Óscar Zaragoza.
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