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Candida spp. are opportunistic yeasts capable of forming biofilms, which contribute to resistance, increasing the urgency for new effective antifungal therapies. Repurposing existing drugs could significantly accelerate the development of novel therapies against candidiasis. We screened the Pandemic Response Box containing 400 diverse drug‐like molecules active against bacteria, viruses or fungi, for inhibitors of Candida albicans and Candida auris biofilm formation. Initial hits were identified based on the demonstration of >70% inhibitory activity. Dose–response assays were used to confirm the antifungal activity of initial hits and establish their potency. The spectrum of antifungal activity of the leading compounds was determined against a panel of medically important fungi, and the in vivo activity of the leading repositionable agent was evaluated in murine models of C. albicans and C. auris systemic candidiasis. The primary screening identified 20 hit compounds, and their antifungal activity and potency against C. albicans and C. auris were validated using dose–response measurements. From these experiments, the rapalog everolimus, emerged as the leading repositionable candidate. Everolimus displayed potent antifungal activity against different Candida spp., but more moderate levels of activity against filamentous fungi. Treatment with everolimus increased survival of mice infected with C. albicans, but not those with C. auris. The screening of the Pandemic Response Box resulted in the identification of several drugs with novel antifungal activity, with everolimus emerging as the main repositionable candidate. Further in vitro and in vivo studies are needed to confirm its potential therapeutic use. [ABSTRACT FROM AUTHOR]

Abstract Protective responses in mice immunized with an interferon-gamma producing strain of Cryptococcus neoformans, H99γ, are associated with IL-17A production by neutrophils. Neutrophil depletion in H99γ-immunized mice did not affect pulmonary fungal burden, indicating that neutrophils are not required for clearance. However, we observed an increase in IL-17A in the lungs of neutrophil-depleted H99γ infected mice, which corresponded to an increase in IL-17A+ γδ+ T cells. Moreover, we observed increased IL-17A+/ CD3+ cells and IL-17A+/γδ+ cells, but decreased IL-17A+/Ly6G+ neutrophils in the lungs of IL-17 receptor (R)A deficient mice compared to wild-type mice. Increased production of IL-17A in neutropenic mice coincided with increased IL-6 and CXCL1, but not Th17 inducing cytokines TGF-β, IL-21 and IL-23. Concurrent depletion of neutrophils and γδ+ T cells reduced IL-17A levels. Our results suggest that γδ+ T cells mediate significant IL-17A production in neutropenic mice during the protective response to C. neoformans infection.

The Peptidoglycan (PG) cell wall of the Lyme disease (LD) spirochete, Borrelia burgdorferi (Bb), contributes to structural and morphological integrity of Bb; is a persistent antigen in LD patients; and has a unique pentapeptide with L-Ornithine as the third amino acid that cross-links its glycan polymers. A borrelial homolog (BB_0167) interacted specifically with borrelilal PG via its peptidoglycan interacting motif (MHELSEKRARAIGNYL); was localized to the protoplasmic cylinder of Bb; and was designated as Borrelia peptidoglycan interacting Protein (BpiP). A bpiP mutant displayed no defect under in vitro growth conditions with similar levels of several virulence-related proteins. However, the burden of bpiP mutant in C3H/HeN mice at day 14, 28 and 62 post-infection was significantly lower compared to control strains. No viable bpiP mutant was re-isolated from any tissues at day 62 post-infection although bpiP mutant was able to colonize immunodeficient SCID at day 28 post-infection. Acquisition or transmission of bpiP mutant by Ixodes scapularis larvae or nymphs respectively, from and to mice, was significantly lower compared to control strains. Further analysis of bpiP mutant revealed increased sensitivity to vancomycin, osmotic stress, lysosomal extracts, human antimicrobial peptide cathelicidin-LL37, complement-dependent killing in the presence of day 14 post-infection mouse serum and increased internalization of CFSC-labeled bpiP mutant by macrophages and dendritic cells compared to control strains. These studies demonstrate the importance of accessory protein/s involved in sustaining integrity of PG and cell envelope during different phases of Bb infection. Author summary: Borrelia burgdorferi (Bb), the agent of Lyme disease, is capable of survival in widely divergent hosts such as the tick vector and numerous vertebrates. Peptidoglycan (PG) cell wall contributes to structural integrity of Bb, remodeling of its cell envelope in response to environmental signals and in modulation of antimicrobial responses in different hosts during the infectious cycle. The glycan polymers of PG are cross-linked via a unique pentapeptide with L-Ornithine as the third amino acid. Here, we demonstrate the role of a borrelial protein, designated as Borrelia peptidoglycan interacting Protein (BpiP), in the patho-physiology of Bb. Deletion of bpiP results in attenuation of infection in immunocompetent C3H/HeN or BALB/c mice unlike in immunodeficient SCID mice. The bpiP mutant is more susceptible to effects of vancomycin, osmotic stress, lysosomal extracts, antimicrobial peptides, complement-dependent killing and increased phagocytosis by macrophages and dendritic cells. These observations demonstrated that cellular and soluble factors of the host immune response limit the colonization of bpiP mutant in immunocompetent hosts. Understanding the role of cell wall components and its accessory factors in the survival of Bb during tick and mammalian phases of infection is anticipated to advance strategies to reduce the incidence of Lyme disease. [ABSTRACT FROM AUTHOR]

Repositioning old drugs can significantly decrease the time and effort that it takes to develop novel antifungal therapeutics, which represents a pressing and unmet clinical need due to the devastating nature of fungal infections. We have previously described the activity of auranofin, a gold thiol compound used to treat rheumatoid arthritis, againstCandida albicansbiofilms. Here we evaluate its antifungal spectrum of action and describe its activity against a variety of medically important fungi. [ABSTRACT FROM PUBLISHER]

Background: Cryptococcus neoformans, the causative agent of cryptococcosis, causes ~ 181,000 deaths annually, with males having a higher incidence of disease than females (7M:3F). The reason for this sex bias remains unclear. We hypothesized that this disparity was due to biological differences between the male and female immune response. Methods: Peripheral blood mononuclear cells (PBMCs) from healthy donors were isolated and infected with C. neoformans ± exogenous testosterone or 17-β-estradiol. C. neoformans, B, T, and NK cell proliferation was quantified by flow cytometry. Cytokine analysis was conducted via protein array or ELISA. Serological testing was conducted to determine previous exposure to C. neoformans. Results: C. neoformans proliferated more in male PBMCs. T cell percentages in both sexes were lower in infected versus uninfected cells. Male PBMCs had lower CD3+, CD4+, and CD8+ T cells percentages during infection compared to females. Cytokine profiles showed differences in uninfected male and female PBMCs, which subsided during infection. Only one donor was sero-negative for prior C. neoformans exposure. There was an effect of estrogen in one dataset. Conclusions: These results suggest that males show an inherent deficit in T cell response during infection, which may contribute to the increased incidence of disease in males. [ABSTRACT FROM AUTHOR]

Dendritic cells (DCs), a vital component of the innate immune system, are considered to lack antigen specificity and be devoid of immunological memory. Strategies that can induce memory-like responses from innate cells can be utilized to elicit protective immunity in immune deficient persons. Here we utilize an experimental immunization strategy to modulate DC inflammatory and memory-like responses against an opportunistic fungal pathogen that causes significant disease in immunocompromised individuals. Our results show that DCs isolated from protectively immunized mice exhibit enhanced transcriptional activation of interferon and immune signaling pathways. We also show long-term memory-like cytokine responses upon subsequent challenge with the fungal pathogen that are abrogated with inhibitors of specific histone modifications. Altogether, our study demonstrates that immunization strategies can be designed to elicit memory-like DC responses against infectious disease. Wormley and colleagues present data showing that vaccine strategies can be devised to prime dendritic cells to respond in a memory-like fashion upon subsequent exposure to a pathogen. [ABSTRACT FROM AUTHOR]

Lyme disease (LD) is a systemic disorder caused by Borrelia burgdorferi . Lyme spirochetes encode for a functional 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGR EC 1.1.1.88) serving as a rate limiting enzyme of the mevalonate pathway that contribute to components critical for cell wall biogenesis. Statins have been shown to inhibit B. burgdorferi in vitro . Using a mouse model of Lyme disease, we found that statins contribute to reducing bacterial burden and altering the murine immune response to favor clearance of spirochetes. [ABSTRACT FROM AUTHOR]