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Investigation
Adaptation of pathogenic fungi to the host and development of new antifungal therapies
Research Lines
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.
Research projects
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: 01/09/2021-31/05/2025
Funding: 143,990 €.
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
Publications
Botulism in Spain: Epidemiology and Outcomes of Antitoxin Treatment, 1997-2019
Peñuelas M, Guerrero-Vadillo M, Valdezate S, Zamora MJ, Leon-Gomez I, Flores-Cuéllar Á, Carrasco G, Díaz-García O, Varela C. (2022). Botulism in Spain: Epidemiology and Outcomes of Antitoxin Treatment, 1997-2019. Toxins (Basel). 20;15(1):2
PUBMED DOIInvasive Streptococcus pyogenes disease in Spain: a microbiological and epidemiological study covering the period 2007-2019
Villalón P, Sáez-Nieto JA, Rubio-López V, Medina-Pascual MJ, Garrido N, Carrasco G, Pino-Rosa S, Valdezate S. (2021). Invasive Streptococcus pyogenes disease in Spain: a microbiological and epidemiological study covering the period 2007-2019. Eur J Clin Microbiol Infect Dis. 2021 Nov;40(11):2295-2303
PUBMED DOIRevisiting the Ancylostoma caninum secretome provides new information on hookworm-host interactions.
Morante T, Shepherd C, Constantinoiu C, Loukas A, Sotillo J. Revisiting the Ancylostoma caninum secretome provides new information on hookworm-host interactions. Proteomics. 2017 Dec;17(23-24).
PUBMED DOIContent with Investigacion .
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Leticia Bernal Martínez
Staff Scientist
ORCID code: 0000-0002-1694-5522
Dr. Bernal-Martínez obtained her degree in Biochemistry from the University of Zaragoza in 2005. She joined the Mycology Reference and Research Laboratory (LRIM) in 2006 under a trainee contract and completed her PhD within the Official Doctoral Program in Microbiology and Parasitology at the Complutense University of Madrid, defending her thesis in 2010 with highest honors (Cum Laude). In 2007, she continued her research activity at LRIM within the framework of the Spanish Network for Research in Infectious Diseases (REIPI). In 2016, she completed a Postgraduate Diploma in Promotion and Management of International Projects (Technical University of Madrid) and undertook a research stay at the Microbiology and Infection Research Domain, Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho (Braga, Portugal). She was subsequently appointed as a PhD researcher within the Biomedical Research Networking Center in Infectious Diseases (CIBERINFEC). Since 2024, she serves as Specialist Scientist at the Carlos III Health Institute (ISCIII) and is responsible for the Diagnostic and Serology Section for Endemic Fungi at the Mycology Reference and Research Laboratory.
Dr. Bernal-Martínez has authored more than 30 peer-reviewed scientific publications and two book chapters. She has actively participated in over 12 research projects and has presented her work at numerous national and international scientific conferences. Her research has focused on human fungal infections, antifungal resistance, therapeutic drug monitoring, genetic variants associated with antifungal metabolism, and the identification of predictive biomarkers of invasive fungal infections. However, her primary expertise lies in the diagnostic field, particularly in the design, optimization, and validation of real-time PCR–based methodologies.
She is currently Principal Investigator of a research project aimed at improving current diagnostic techniques for invasive fungal infections, evaluating emerging diagnostic technologies, and studying primary fungal pathogens. A substantial part of her work has been transferred to the Spanish National Health System and to research centers in Latin America. Many of the diagnostic methodologies developed have been incorporated into the official service portfolio of ISCIII. She has collaborated with multiple hospitals through research projects and clinical trials applying these technologies, as well as with the ISCIII spin-off company Micomol S.L.
Dr. Bernal-Martínez has supervised several Master’s and Undergraduate Final Degree Projects from students at the Complutense University of Madrid and the University of Alcalá. She is a member of the teaching staff of the UNED-ISCIII PhD Program in Biomedical Sciences and Public Health and serves as lecturer in the Master’s Program in Public Health and Research in Infectious Diseases at the University of Alcalá. -
Laura Alcázar Fuoli
Research Scientist
Graduated in Biochemistry from the Autonomous University of Madrid and PhD in Biology from the Complutense University of Madrid in 2006. She completed her doctoral thesis at the National Center of Microbiology (CNM) under the direction of Dr. Emilia Mellado, in the study of the synthesis of Ergosterol in Aspergillus fumigatus. In 2012 Laura joined the reference laboratory in mycology with a researcher contract for the “Miguel Servet” program after having worked for three years as an associate researcher at Imperial College London. During that period his research focused on host adaptation mechanisms and virulence factors of A. fumigatus. In 2014 he obtained the position of Senior Scientist of Public Research Organizations carrying out his research work at the CNM.
List of staff