Warfare and defense: The host response to Cryptococcus infection

Global trends in Cryptococcus and its interactions with the host immune system: a bibliometric analysis

Objectives

This manuscript undertakes a systematic examination of the research landscape concerning global Cryptococcus species and their dynamism with the host immune system spanning the past decade. It furnishes a detailed survey of leading knowledge institutions and critical focal points in this area, utilizing bibliometric analysis.

Methods

VOSviewer and CiteSpace software platforms were employed to systematically analyze and graphically depict the relevant literature indexed in the WoSCC database over the preceding ten years.

Results

In the interval between October 1, 2013, and October 1, 2023, a corpus of 795 publications was amassed. The primary research institutions involved in this study include Duke University, the University of Minnesota, and the University of Sydney. The leading trio of nations, in terms of publication volume, comprises the United States, China, and Brazil. Among the most prolific authors are Casadevall, Arturo; Wormley, Floyd L., Jr.; and Olszewski, Michal A., with the most highly cited author being Perfect, Jr. The most esteemed journal is Mbio, while Infection and Immunity commands the highest citation frequency, and the Journal of Clinical Microbiology boasts the most significant impact factor. Present research foci encompass the intricate interactions between Cryptococcus pathogenesis and host immunity, alongside immune mechanisms, complications, and immunotherapies.

Conclusion

This represents the first exhaustive scholarly review and bibliometric scrutiny of the evolving landscapes in Cryptococcus research and its interactions with the host immune system. The analyses delineated herein provide insights into prevailing research foci and trajectories, thus furnishing critical directions for subsequent inquiries in this domain.

Pyrifenox, an ergosterol inhibitor, differentially affects Cryptococcus neoformans and Cryptococcus gattii

Cryptococcosis is a life-threatening fungal infection. New therapeutic approaches are necessary to combat cryptococcosis, as the currently available therapeutic protocols are expensive and generally result in deleterious side effects. Pyrifenox is an antifungal compound that affects phytopathogens by inhibiting the biosynthesis of ergosterol. In this study, we investigated the effects of pyrifenox on Cryptococcus neoformans and Cryptococcus gattii growth, capsule architecture and export of the major capsule component, glucuroxylomannan (GXM). Pyrifenox inhibited the growth of C. neoformans, but was significantly less effective against C. gattii. The resistance of C. gattii to pyrifenox was associated with the expression of efflux pump genes, particularly AFR1 and AFR2, since mutant cells lacking expression of these genes became sensitive to pyrifenox. Analysis of the cryptococcal capsule by India ink counterstaining, immunofluorescence, and scanning electron microscopy showed that pyrifenox affected capsular dimensions in both species. However, GXM fibers were shorter and uniformly distributed in C. neoformans, whereas in C. gattii the number of fibers was reduced. Pyrifenox-treated C. gattii developed unusually long chains of undivided cells. The secretion of GXM was markedly reduced in both species after treatment with pyrifenox. Altogether, the results indicated that pyrifenox differently affects C. neoformans and C. gattii. In addition, it highlights a potential role for pyrifenox as an inhibitor of GXM export in experimental models involving pathogenic cryptococci.

Fine Particulate Matter (PM2.5) Promotes CD146 Expression in Alveolar Epithelial Cells and Cryptococcus neoformans Pulmonary Infection

Air pollution is a leading cause of increasing infectious lung diseases. Pulmonary cryptococcosis is a fatal fungal pneumonia in acquired immunodeficiency syndrome patients. In some cases, the pathogen Cryptococcus neoformans also develops dormant nodules in immunocompetent individuals. In the present study, we demonstrated that fine particulate matter (PM₂.₅) increased CD146 expression in alveolar epithelial cells and promoted C. neoformans pulmonary infection. Aryl hydrocarbon receptor (AhR) signaling was required for increased expression of CD146 in epithelial cells treated with PM₂.₅. In a murine model of pulmonary infection, PM₂.₅ promoted fungal infection, and CD146 deficiency decreased the fugal burden of C. neoformans. Our study may highlight the importance of air pollution to lung mycosis and CD146 as a target for preventing infectious lung diseases.