Biology subjects

Monteoliva, L.

Publications and source records attributed to Monteoliva, L..

6 recordsLinked to original sources

bioRxiv2026

Thirty years of fluconazole therapy selects an azole-resistant Candida albicans isolate with a pre-adapted physiological, metabolic and structural state

Azole resistance in Candida albicans is traditionally attributed to alterations in drug targets and efflux mechanisms; however, how long-term antifungal exposure reshapes fungal physiology remains incompletely understood. Here, we characterize a fluconazole-resistant C. albicans clinical isolate (PUJ256) recovered from a patient with chronic mucocutaneous candidiasis after more than 30 years of continuous fluconazole therapy. Compared with the reference strain SC5314, the resistant isolate exhibited a clear fitness trade-off, with reduced filamentation and increased membrane vulnerability under basal conditions, yet enhanced fitness in the presence of fluconazole. Integration of phenotypic analyses with label-free quantitative proteomics revealed extensive metabolic remodelling, including coordinated regulation of central carbon metabolism, ergosterol biosynthesis and redox homeostasis. Notably, mitochondrial membrane potential was preserved in the resistant isolate under fluconazole stress, whereas the susceptible strain exhibited mitochondrial depolarization together with activation of MAPK signalling pathways. In addition, the resistant isolate displayed reduced susceptibility to phagocytosis under antifungal exposure, consistent with an increased capacity for persistence in the context of ongoing treatment. Collectively, our findings indicate that long-term azole resistance in C. albicans PUJ256 is associated with a stable, pre-adapted physiological state characterized by metabolic reprogramming and mitochondrial resilience. The prolonged antifungal exposure of this isolate provides a valuable opportunity to explore adaptative strategies that extend beyond canonical mechanisms, pointing to mitochondrial function and metabolic plasticity as potential targets for therapeutic intervention.

microbiology↗

bioRxiv2024

From high protection to lethal effect: diverse outcomes of immunization against invasive candidiasis with different Candida albicans extracellular vesicles

Extracellular vesicles (EVs) from Candida albicans can elicit immune responses, positioning them as promising acellular vaccine candidates. We characterized EVs from an avirulent C. albicans cell wall mutant (ecm33{Delta}) and evaluated their protective potential against invasive candidiasis. EVs from the yeast (YEVs) and hyphal (HEVs) forms of the SC5314 wild-type strain were also tested, yielding high survival rates with SC5314 YEVs (91%) and ecm33 YEVs immunization (64%). Surprisingly, HEV immunization showed a dual effect, resulting in 36% protection but also causing premature death in some mice. Proteomic analyses revealed distinct profiles among the top 100 proteins in the different EVs which may explain these effects: a shared core of 50 immunogenic proteins such as Pgk1, Cdc19, and Fba1; unique, relevant immunogenic proteins in SC5314 YEVs, and proteins linked to pathogenesis, like Ece1 in SC5314 HEVs. Sera from SC5314 YEVs-immunized mice showed the highest IgG2a titers and moderate IL-17, IFN-{gamma}, and TNF- levels, indicating the importance of both humoral and cellular responses for protection. These findings highlight the distinct immunogenic properties of C. albicans EVs, suggesting their potential in acellular vaccine development while emphasizing the need to carefully evaluate pathogenic risks associated with certain EVs.

microbiology↗

bioRxiv2023

Unravelling the Role of Candida albicans Prn1 in the Oxidative Stress Response Through a Proteomic Approach

Candida albicans Prn1 is a protein that shares similarities with mammalian Pirin but with an unknown function in the yeast. Orthologues of Prn1 have been identified in other pathogenic fungi but not in Saccharomyces cerevisiae, suggesting a relationship with pathogenesis. Prn1 increase in abundance after H2O2 treatment has been shown previously, thus, in the present work, C. albicans prn1{Delta} mutant and the corresponding wild-type strain SN250 have been treated with H2O2 and their response was studied by quantitative differential proteomics. These assays indicated a lower increase of proteins with oxidoreductase activity after treatment in the prn1{Delta} strain compared to the wild type, as well as an increase in proteasome-activating proteins and a decrease in translation-involved proteins. Accordingly, Prn1 absence, under H2O2 treatment, led to a lower survival rate and a higher percentage of apoptosis, together with higher reactive oxygen species levels and higher proteasome activity. Besides, remarkable differences in the abundance of some transcription factors were observed between the two strains. Mnl1, involved in Prn1 expression, Bas1, Tiff33, and orf19.1150 presented an inverse pattern of expression under H2O2 treatment respect to Nrg1, a Mnl1 antagonist. Interestingly, orf19.4850, a protein orthologue to S. cerevisiae Cub1, has shown to be involved in the response to H2O2 presenting a conserved proteasome function. Under basal conditions, the proteomics results indicate a possible involvement of Prn1 in mitochondrial oxidative stress detoxication. Our experiments confirm Prn1 as a relevant actor in the oxidative response. ImportanceCandida albicans is a human opportunistic pathogen included in the WHO fungal priority pathogens list. The increase in resistant strains necessitates the discovery of new targets for antifungal therapies. Our research sheds light on the important role of the previously uncharacterized C. albicans protein Prn1 during the oxidative stress response. Study of the proteome remodelling under oxidative stress unveils the role of Prn1 in the decreased reactive oxygen species levels and the consequences, such as death by apoptosis and necrosis or cell growth delay. A proteomics approach allowed the identification of several proteins potentially involved in Prn1 activity, such as oxidoreductases and transcription factors. The lack of Prn1 orthologues in Saccharomyces cerevisiae but the presence in other Candida and Aspergillus species implicates this protein in pathogenesis and suggests that it may serve as a candidate for new drug targets.

microbiology↗

bioRxiv2022

Statistical evaluation of metaproteomics and 16s rRNA amplicon sequencing techniques for the study of the gut microbiota establishment of infants with cystic fibrosis

The newborn screening for cystic fibrosis (CF) can identify affected but still asymptomatic infants. The selection of omic technique for gut microbiota study is therefore crucial due to both the small amount of feces available and the low microorganism load. Our aim was to compare the agreement between 16S rRNA amplicon sequencing and metaproteomics by a robust statistical analysis including McNemar (taxa presence) test and Bland-Altman (taxa abundance) data plotting for studying the sequential establishment of the gut microbiota during the first year of life in 8 infants with CF (28 fecal samples). The taxonomic assignation was similar by the two techniques, whereas certain discrepancies were observed in the abundance detection, mostly the underrepresentation of Bifidobacterium and the overestimation of certain Firmicutes and Proteobacteria by amplicon sequencing. During the first months of life, the CF gut microbiota is characterized by poor alpha diversity, a significant enrichment of Ruminococcus gnavus, the expression of certain virulent bacterial traits, and the detection of human inflammation-related proteins. Our study provides an extended comparative analysis with robust statistical support that could optimize the use of both approaches for gut microbiota research. Metaproteomics provides information on composition and functionality, as well as data on host-microbiome interactions. Its strength is the identification and quantification of Actinobacteria and certain classes of Firmicutes. Both techniques detected an aberrant microbiota in infants with CF during their first year of life, dominated by the enrichment of R. gnavus within a human inflammatory environment.

microbiology↗

bioRxiv2020

Extending the proteomic characterization of Candida albicans exposed to stress and apoptotic inducers through data-independent acquisition mass spectrometry

Candida albicans is a commensal fungus that causes systemic infections in immunosuppressed patients. In order to deal with the changing environment during commensalism or infection, C. albicans must reprogram its proteome. Characterizing the stress-induced changes in the proteome that C. albicans uses to survive should be very useful in the development of new antifungal drugs. We studied the C. albicans global proteome after exposure to hydrogen peroxide (H2O2) and acetic acid (AA), using a DIA-MS strategy. More than 2000 C. albicans proteins were quantified using an ion library previously constructed using DDA-MS. C. albicans responded to treatment with H2O2 with an increase in the abundance of many proteins involved in the oxidative stress response, protein folding and proteasome-dependent catabolism, which led to an increased proteasome activity. The data revealed a previously unknown key role for Prn1, a protein similar to pirins, in the oxidative stress response. Treatment with AA resulted in a general decrease in the abundance of proteins involved in amino acid biosynthesis, protein folding, and rRNA processing. Almost all proteasome proteins declined, as did proteasome activity. Apoptosis was observed after treatment with H2O2, but not AA. A targeted proteomic study of 32 proteins related to apoptosis in yeast supported the results found by DIA-MS and allowed the creation of an efficient method to quantify relevant proteins after treatment with stressors (H2O2, AA, and amphotericin B). This approach also uncovered a main role for Oye32, an oxidoreductase, suggesting this protein as a possible apoptotic marker common to many stressors. IMPORTANCEFungal infections are a worldwide health problem especially in immunocompromised patients and patients with chronic disorders. Invasive candidiasis, mainly caused by C. albicans, are among the most common fungal diseases. Despite the existence of treatments to combat candidiasis the spectra of drugs available are limited. For the discovery of new drug targets is essential to know the pathogen response to different stress conditions. Our study provides a global vision of proteomic remodeling in C. albicans after exposure to different agents such as hydrogen peroxide, acetic acid and amphotericin B that can cause apoptotic cell death. This results revealed the significance of many proteins related to oxidative stress response and proteasome activity among others. Of note, the discovery of Prn1 as a key protein in the defence against oxidative stress as well the increase in the abundance of Oye32 protein when apoptotic process occurred point out them as possible drug targets.

microbiology↗

bioRxiv2020

Small extracellular vesicles secreted by Candida albicans hyphae have highly diverse protein cargoes that include virulence factors and stimulate macrophages

Extracellular vesicles (EVs) have been described as mediators of microorganism survival and interaction with the host. In Candida albicans, a relevant commensal fungal pathogen, the dimorphic transition is an important virulence trait in candidiasis. We have analyzed EVs secreted by yeast (YEVs) or hyphal cells (HEVs) from C. albicans, finding interesting differences in both size distribution and protein loading. In general, HEVs were smaller and carried a much more diverse protein cargo than YEVs, including most of the proteins identified in YEVs, which were mainly cell surface proteins. Virulence factors such as phospholipases, aspartic proteases (Saps), adhesins and invasins, and the precursor protein of candidalysin toxin Ece1p were also detected. HEVs were also enriched in proteasomal and ribosomal proteins, and in enzymes from amino acid biosynthetic pathways, all involved in protein metabolism, as well as proteins related to intracellular protein transport and components of the ESCRT pathway related to exosome biogenesis. Both types of EV presented immune reactivity with human sera from patients suffering invasive candidiasis. In our conditions, only HEVs could elicit the release of TNF by activated macrophages. This first analysis of C. albicans HEVs shows their relevance to pathogenesis and possible new diagnostics or treatments.

microbiology↗