Publications by authors named "Jose P Guirao-Abad"

The source and roles of fibroblasts and T-cells during maladaptive remodeling and myocardial fibrosis in the setting of pulmonary arterial hypertension (PAH) have been long debated. We demonstrate, using single-cell mass cytometry, a subpopulation of endogenous human cardiac fibroblasts expressing increased levels of CD4, a helper T-cell marker, in addition to myofibroblast markers distributed in human fibrotic RV tissue, interstitial and perivascular lesions in SUGEN/Hypoxia (SuHx) rats, and fibroblasts labeled with pdgfrα CreERt2/+ in R26R-tdTomato mice. Recombinant IL-1β increases IL-1R, CCR2 receptor expression, modifies the secretome, and differentiates cardiac fibroblasts to form CD68-positive cell clusters.

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Fungi have traditionally been considered opportunistic pathogens in primary infections caused by virulent bacteria, protozoan, or viruses. Consequently, antimycotic chemotherapy is clearly less developed in comparison to its bacterial counterpart. Currently, the three main families of antifungals (polyenes, echinocandins, and azoles) are not sufficient to control the enormous increase in life-threatening fungal infections recorded in recent decades.

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One of the most potent opportunistic fungal pathogens of humans is , an environmental mold that causes a life-threatening pneumonia with a high rate of morbidity and mortality. Despite advances in therapy, issues of drug toxicity and antifungal resistance remain an obstacle to effective therapy. This underscores the need for more information on fungal pathways that could be pharmacologically manipulated to either reduce the viability of the fungus during infection, or to unleash the fungicidal potential of current antifungal drugs.

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Aspergillus fumigatus is a human-pathogenic mold that extracts nutrients from the environment or from host tissues by secreting hydrolytic enzymes. The ability of A. fumigatus to adjust secretion levels in proportion to demand relies on the assistance of the unfolded protein response (UPR), an adaptive stress response pathway that regulates the unique protein-folding environment of the endoplasmic reticulum (ER).

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Article Synopsis
  • The Mitogen-Activated Protein kinase (MAPK) pathways in fungi, particularly the HOG pathway, are crucial for responding to environmental changes and stress, impacting their survival and colonization in hosts.
  • A study found that the antifungal Micafungin (MF) had the same minimum inhibitory concentration in both a parent strain and a mutant, indicating no difference in susceptibility, and both strains showed similar impaired cell viability after treatment.
  • Unlike the positive control Amphotericin B, MF did not activate specific antioxidant genes or influence reactive oxygen species levels, suggesting that MF's toxic effects do not involve the Hog1 MAPK pathway or oxidative stress in affected cells.
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The unfolded protein response (UPR) is a signaling network that maintains homeostasis of the endoplasmic reticulum (ER). In the human-pathogenic fungus , the UPR is initiated by activation of an endoribonuclease (RNase) domain in the ER transmembrane stress sensor IreA, which splices the downstream mRNA into its active form, encoding the master transcriptional regulator of the pathway. Small-molecule inhibitors against IRE1, the human ortholog of IreA, have been developed for anticancer therapy, but their effects on the fungal UPR are unexplored.

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The potential fungicidal action of the natural extracts, carnosic acid (obtained from rosemary) and propolis (from honeybees' panels) against the highly prevalent yeast , used herein as an archetype of pathogenic fungi, was tested. The separate addition of carnosic acid and propolis on exponential cultures of the standard SC5314 strain caused a moderate degree of cell death at relatively high concentrations. However, the combination of both extracts, especially in a 1:4 ratio, induced a potent synergistic pattern, leading to a drastic reduction in cell survival even at much lower concentrations.

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Article Synopsis
  • The HOG MAP kinase pathway is essential for Candida albicans to respond to various stresses, particularly to the antifungal drug amphotericin B (AMB).
  • Mutants lacking the Hog1 protein, part of this pathway, show increased susceptibility to AMB due to a failure in sensing and surviving oxidative stress induced by the drug.
  • The study found that both the phosphorylation and kinase activity of Hog1 are crucial for survival during AMB treatment, while the drug also triggers Hog1-independent processes like trehalose synthesis and influences intracellular reactive oxygen species (ROS) levels.
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. Fungal infections have increased in recent decades, with being the fourth most common aetiological agent of nosocomial infections. Disaccharide trehalose has been proposed as a target for the development of new antifungals.

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Article Synopsis
  • - Certain yeasts produce killer toxins (mycocins) that can harm sensitive yeast and fungi, a phenomenon observed in various environmental species.
  • - Recent research found cheese-derived yeast strains that produce these toxins and indicated that mutants lacking the MAPK Hog1 signal pathway are more susceptible to the mycocins, unlike other mutants.
  • - The study revealed that while Hog1's phosphorylation is crucial for survival against these toxins and coping with osmotic and oxidative stresses, overactive catalase does not provide protection, hinting at other stress-related mechanisms involved.
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Micafungin belongs to the antifungal family of echinocandins, which act as noncompetitive inhibitors of the fungal cell wall β-1,3-d-glucan synthase. Since is the most prevalent pathogenic fungus in humans, we study the involvement of micafungin in the modulation of the inflammatory response developed by human tissue macrophages against The MIC for micafungin was 0.016 μg/ml on the SC5314 standard strain.

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Arsenic is a toxic metalloid widespread in nature. Recently, it has been demonstrated a main role of the transcription factor Pho4 in the acquisition of tolerance to arsenic-derived compounds, arsenite and arsenate in Candida albicans. Here, the effect of these compounds on this pathogenic yeast has been analyzed.

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The hypothetical role played by the intracellular formation of reactive oxygen species (ROS) in the fungicidal action carried out by Amphotericin B (AmB) and Micafungin (MF) was examined in Candida albicans, which remains the most prevalent fungal pathogen. The clinical MICs for MF and AmB were 0.016 and 0.

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A double homozygous atc1Δ/atc1Δ/ntc1Δ/ntc1Δ mutant (atc1Δ/ntc1Δ KO) was constructed in the pathogen opportunistic yeast Candida parapsilosis by disruption of the two chromosomal alleles coding for NTC1 gene (encoding a neutral trehalase) in a Cpatc1Δ/atc1Δ background (atc1Δ KO strain, deficient in acid trehalase). The Cpatc1Δ/ntc1Δ KO mutant failed to counteract the inability of Cpatc1Δ cells to metabolize exogenous trehalose and showed a similar growth pattern on several monosaccharides and disaccharides. However, upon prolonged incubation in either rich medium (YPD) or nutrient-starved medium the viability of Cpatc1Δ cells exhibited a sensitive phenotype, which was augmented by further CpNTC1/NTC1 disruption.

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The hypothetical capacity of amphotericin B to suppress the formation of germ-tubes, which is the first step of yeast-to-hypha conversion in Candida albicans, has been investigated in the wild-type strain CEY.1 (CAI.4-URA⁺).

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Validamycin A has been successfully applied in the fight against phytopathogenic fungi. Here, the putative antifungal effect of this pseudooligosaccharide against the prevalent human pathogen Candida albicans was examined. Validamycin A acts as a potent competitive inhibitor of the cell-wall-linked acid trehalase (Atc1p).

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Candida albicans exponential yeast cells are able to face environmental challenges by mounting a rapid and efficient "general stress response". Here we show that one of the main components of this response consists of the intracellular protective accumulation of the non-reducing disaccharide trehalose and two polyols, glycerol and D-arabitol, an accumulation that occurs in a stress-specific dependent manner. Thus, oxidative exposures promoted a marked increase in both trehalose and D-arabitol in the wild type strain, RM-100, whereas the glycerol content remained virtually unaffected with respect to basal levels.

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The putative candicidal activity of resveratrol is currently a matter of controversy. Here, the antifungal activity as well as the antioxidant response of resveratrol against Candida albicans, have been tested in a set of strains with a well-established genetic background At the doses usually employed in antifungal tests (10-40 μg/ml), resveratrol has no effect on the exponential growth of the C. albicans CAI.

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