Publications by authors named "Dena Toffaletti"

Cryptococcal meningitis (CM) causes significant global morbidity and mortality. Current therapeutic strategies rely on deoxycholated or liposomal forms of the polyene amphotericin B. Nystatin is also a polyene with broad-spectrum antimicrobial activity.

View Article and Find Full Text PDF

Unlabelled: Cryptococcal meningitis causes an estimated 112,000 global deaths per annum. Genomic and phenotypic features of the infecting strain of spp. have been associated with outcomes from cryptococcal meningitis.

View Article and Find Full Text PDF

Invasive fungal diseases are a major threat to human health, resulting in more than 1.5 million annual deaths worldwide. The arsenal of antifungal therapeutics remains limited and is in dire need of drugs that target additional biosynthetic pathways that are absent from humans.

View Article and Find Full Text PDF

Trehalose-6-phosphate synthase (TPS1) was identified as a virulence factor for and a promising therapeutic target. This study reveals previously unknown roles of TPS1 in evasion of host defenses during pulmonary and disseminated phases of infection. In the pulmonary infection model, TPS1-deleted () are rapidly cleared by mouse lungs whereas TPS1-sufficent WT (H99) and revertant (:) strains expand in the lungs and disseminate, causing 100% mortality.

View Article and Find Full Text PDF

Biolistic transformation of Cryptococcus neoformans is used as a molecular tool to genetically alter or delete targeted genes. The DNA is introduced into the yeast on DNA-coated gold beads by a helium shock wave produced using a biolistic particle system. The procedure often involves insertion of a dominant selectable marker into the desired site by homologous recombination.

View Article and Find Full Text PDF

Invasive fungal infections are a significant public health concern, with mortality rates ranging from 20% to 85% despite current treatments. Therefore, we examined whether a ketogenic diet could serve as a successful treatment intervention in murine models of and infection in combination with fluconazole-a low-cost, readily available antifungal therapy. The ketogenic diet is a high-fat, low-carbohydrate diet that promotes fatty acid oxidation as an alternative to glycolysis through the production of ketone bodies.

View Article and Find Full Text PDF
Article Synopsis
  • Cryptococcal meningitis is a major cause of death in people with HIV/AIDS, but there's still a limited understanding of how the fungus changes during infection.
  • A study analyzed the whole genomes of 372 clinical isolates from patients in Malawi and Cameroon, revealing that Cameroonian isolates are more genetically uniform compared to their Malawian counterparts, and show different rates of mutations in key genes.
  • Longitudinal samples taken from patients in Cameroon highlighted genetic changes during infection and revealed mixed infections in 13% of patients, showcasing the evolutionary dynamics of the fungus in this context.
View Article and Find Full Text PDF

Cryptococcal meningoencephalitis (CM) is a devastating fungal disease with high morbidity and mortality. The current regimen that is standard-of-care involves a combination of three different drugs administered for up to one year. There is a critical need for new therapies due to both toxicity and inadequate fungicidal activity of the currently available antifungal drugs.

View Article and Find Full Text PDF

Patients receiving the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib have an increased likelihood of fungal infections. The objectives of this study were to determine if Cryptococcus neoformans infection severity was isolate dependent with BTK inhibition and whether blocking BTK impacted infection severity in a mouse model. We compared four clinical isolates from patients on ibrutinib to virulent (H99) and avirulent (A1-35-8) reference strains.

View Article and Find Full Text PDF

Unlabelled: Invasive fungal diseases are a major threat to human health, resulting in more than 1.5 million annual deaths worldwide. The arsenal of antifungal therapeutics remains limited and is in dire need of novel drugs that target additional biosynthetic pathways that are absent from humans.

View Article and Find Full Text PDF
Article Synopsis
  • Cryptococcus neoformans causes cryptococcosis, which leads to around 180,000 deaths annually, particularly affecting patients with HIV, highlighting a need to understand the link between genetic diversity of the fungus and clinical outcomes.
  • A genome-wide association study (GWAS) of 284 C. neoformans isolates from Malawi reveals variants associated with fungal growth rates and burdens, with significant variations in genes related to metabolism and growth.
  • The findings demonstrate that glycolysis is crucial for the fungus's survival in the central nervous system and may influence patient mortality, suggesting that understanding these genetic factors can improve treatment outcomes for cryptococcosis.
View Article and Find Full Text PDF

Cryptococcal Meningitis (CM) is uniformly fatal if not treated, and treatment options are limited. We previously reported on the activity of APX2096, the prodrug of the novel Gwt1 inhibitor APX2039, in a mouse model of CM. Here, we investigated the efficacy of APX2039 in mouse and rabbit models of CM.

View Article and Find Full Text PDF

Many aspects of the host response to invasive cryptococcal infections remain poorly understood. In order to explore the pathobiology of infection with common clinical strains, we infected BALB/cJ mice with , , or sham control, and assayed host transcriptomic responses in peripheral blood. Infection with resulted in markedly greater fungal burden in the CNS than , as well as slightly higher fungal burden in the lungs.

View Article and Find Full Text PDF
Article Synopsis
  • Cryptococcus neoformans is a dangerous fungal pathogen that can significantly affect the human central nervous system, leading to high rates of illness and death, especially in patients with cryptococcal meningoencephalitis.
  • This research involved analyzing yeast transcriptomes from patient cerebrospinal fluid samples to understand the genetic behaviors of C. neoformans and Cryptococcus gattii in various environments.
  • Key findings included the identification of genes important for survival and virulence, with particular emphasis on carbon metabolism and stress responses, leading to the discovery of a glycoprotein gene that impacts the virulence of these fungi in animal models.
View Article and Find Full Text PDF

The environmental yeast Cryptococcus neoformans is the most common cause of deadly fungal meningitis in primarily immunocompromised populations. A number of factors contribute to cryptococcal pathogenesis. Among them, inositol utilization has been shown to promote C.

View Article and Find Full Text PDF

Cryptococcosis is an infectious disease of worldwide distribution, caused by encapsulated yeasts belonging to the phylum Basidiomycota. The genus includes several species distributed around the world. The / species complex is largely responsible for most cases of cryptococcosis.

View Article and Find Full Text PDF
Article Synopsis
  • * When comparing ST5 and non-ST5 strains, both showed similar lab characteristics but ST5 had more variability in size and induced stronger initial inflammation responses in host models despite lower overall virulence.
  • * The observed differences in ST5 may give it an advantage in adapting to new environments, particularly in immunocompetent individuals, suggesting an evolutionary aspect to its pathogenicity.
View Article and Find Full Text PDF

is an opportunistic fungal pathogen that at its peak epidemic levels caused an estimated million cases of cryptococcal meningitis per year worldwide. This species can grow in diverse environmental (trees, soil and bird excreta) and host niches (intracellular microenvironments of phagocytes and free-living in host tissues). The genetic basic for adaptation to these different conditions is not well characterized, as most experimental work has relied on a single reference strain of .

View Article and Find Full Text PDF

AP-1-like transcription factors play evolutionarily conserved roles as redox sensors in eukaryotic oxidative stress responses. In this study, we aimed to elucidate the regulatory mechanism of an atypical yeast AP-1-like protein, Yap1, in the stress response and virulence of expression was induced and involved not only by oxidative stresses, such as HO and diamide, but also by other environmental stresses, such as osmotic and membrane-destabilizing stresses. Yap1 was distributed throughout both the cytoplasm and the nucleus under basal conditions and more enriched within the nucleus in response to diamide but not to other stresses.

View Article and Find Full Text PDF

spp., important fungal pathogens, are the leading cause of fungus-related mortality in human immunodeficiency virus-infected patients, and new therapeutic options are desperately needed. Isavuconazonium sulfate, a newer triazole antifungal agent, was studied to characterize the exposure-response relationship in a rabbit model of cryptococcal meningoencephalitis.

View Article and Find Full Text PDF

Genotypic diversity and fluconazole susceptibility of 82 Cryptococcus neoformans and Cryptococcus gattii isolates from 60 renal transplant recipients in Brazil were characterized. Clinical characteristics of the patients and prognostic factors were analysed. Seventy-two (87.

View Article and Find Full Text PDF

Cryptococcal meningitis (CM), caused primarily by , is uniformly fatal if not treated. Treatment options are limited, especially in resource-poor geographical regions, and mortality rates remain high despite current therapies. Here we evaluated the and activity of several compounds, including APX001A and its prodrug, APX001, currently in clinical development for the treatment of invasive fungal infections.

View Article and Find Full Text PDF

The disaccharide trehalose is critical to the survival of pathogenic fungi in their human host. Trehalose-6-phosphate synthase (Tps1) catalyzes the first step of trehalose biosynthesis in fungi. Here, we report the first structures of eukaryotic Tps1s in complex with substrates or substrate analogues.

View Article and Find Full Text PDF

Trehalose is a disaccharide essential for the survival and virulence of pathogenic fungi. The biosynthesis of trehalose requires trehalose-6-phosphate synthase, Tps1, and trehalose-6-phosphate phosphatase, Tps2. Here, we report the structures of the N-terminal domain of Tps2 (Tps2NTD) from Candida albicans, a transition-state complex of the Tps2 C-terminal trehalose-6-phosphate phosphatase domain (Tps2PD) bound to BeF3 and trehalose, and catalytically dead Tps2PD(D24N) from Cryptococcus neoformans bound to trehalose-6-phosphate (T6P).

View Article and Find Full Text PDF

Quorum sensing (QS) is a bacterial communication mechanism in which secreted signaling molecules impact population function and gene expression. QS-like phenomena have been reported in eukaryotes with largely unknown contributing molecules, functions, and mechanisms. We identify Qsp1, a secreted peptide, as a central signaling molecule that regulates virulence in the fungal pathogen Cryptococcus neoformans.

View Article and Find Full Text PDF