Extracellular Vesicles From Sporothrix brasiliensis Yeast Cells Increases Fungicidal Activity in Macrophages

Extracellular Vesicles from Dendritic Cells Protect Against Sporothrix brasiliensis Yeast Cells

Sporotrichosis is an emerging subcutaneous mycotic zoonosis that affects the skin, lymphatic system, and other organs of humans and animals. Like other infectious fungal diseases, it becomes even more severe when it affects immunosuppressed patients. This infection has a global distribution and is endemic in some regions of Brazil and it is an important zoonotic public health problem. The disease is caused by a complex of at least four pathogenic species, including Sporothrix brasiliensis. The immunological response against these species has not yet been completely elucidated. Still, structures such as extracellular vesicles could carry important components that can contribute to the modulation and control of this significant infection. Thus, this work aims to analyze the participation of EVs from naïve dendritic cells and EVs from DCs previously primed with S. brasiliensis yeast and primed with EVs from the fungus in the immune response against experimental sporotrichosis in murine models. The groups that received EVs from DCs primed with S. brasiliensis or their EVs showed a significant decrease in fungal load compared to the negative control group. When we analyzed the cytokine profile in the skin of mice treated with EVs before infection, we observed an increase in IFN-ℽ, TNF-α, IL-17, and IL-10, mainly in animals previously treated with EVs from DCs cultivated with yeast cells. It is worth highlighting that all prophylactic protocols modulated and minimized fungal growth compared to the control; that is, EVs contributed to the control of the infection and acted in favor of the host, demonstrating a protective character.

Unveiling the fungal frontier: mycological insights into inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic recurrent gastrointestinal disease that seriously affects the quality of life of patients around the world. It is characterized by recurrent abdominal pain, diarrhea, and mucous bloody stools. There is an urgent need for more accurate diagnosis and effective treatment of IBD. Accumulated evidence suggests that gut microbiota plays an important role in the occurrence and development of gut inflammation. However, most studies on the role of gut microbiota in IBD have focused on bacteria, while fungal microorganisms have been neglected. Fungal dysbiosis can activate the host protective immune pathway related to the integrity of the epithelial barrier and release a variety of pro-inflammatory cytokines to trigger the inflammatory response. Dectin-1, CARD9, and IL-17 signaling pathways may be immune drivers of fungal dysbacteriosis in the development of IBD. In addition, fungal-bacterial interactions and fungal-derived metabolites also play an important role. Based on this information, we explored new strategies for IBD treatment targeting the intestinal fungal group and its metabolites, such as fungal probiotics, antifungal drugs, diet therapy, and fecal microbiota transplantation (FMT). This review aims to summarize the fungal dysbiosis and pathogenesis of IBD, and provide new insights and directions for further research in this emerging field.

Hidden allies: how extracellular vesicles drive biofilm formation, stress adaptation, and host-immune interactions in human fungal pathogens

Pathogenic fungi pose a significant threat to human health, especially given the rising incidence of invasive fungal infections and the emergence of drug-resistant strains. This requires the development of vaccines and the advancement of antifungal strategies. Recent studies have focused on the roles of fungal extracellular vesicles (EVs) in intercellular communication and host-pathogen interactions. EVs are nanosized, lipid membrane-bound particles that facilitate the transfer of proteins, lipids, and nucleic acids. Here, we review the multifaceted functions of EVs produced by different human fungal pathogens, highlighting their importance in the response of fungal cells to different environmental cues and their interactions with host immune cells. We summarize the current state of research on EVs and how leveraging this knowledge can lead to innovative approaches in vaccine development and antifungal treatment.

The emerging role of extracellular vesicles in fungi: a double-edged sword

Fungi are eukaryotic microorganisms found in nature, which can invade the human body and cause tissue damage, inflammatory reactions, organ dysfunctions, and diseases. These diseases can severely damage the patient's body systems and functions, leading to a range of clinical symptoms that can be life-threatening. As the incidence of invasive fungal infections has progressively increased in the recent years, a wealth of evidence has confirmed the "double-edged sword" role of fungal extracellular vesicles (EVs) in intercellular communication and pathogen-host interactions. Fungal EVs act as mediators of cellular communication, affecting fungal-host cell interactions, delivering virulence factors, and promoting infection. Fungal EVs can also have an induced protective effect, affecting fungal growth and stimulating adaptive immune responses. By integrating recent studies, we discuss the role of EVs in fungi, providing strong theoretical support for the early prevention and treatment of invasive fungal infections. Finally, we highlight the feasibility of using fungal EVs as drug carriers and in vaccine development.

Innate Immune Responses to Sporothrix schenckii: Recognition and Elimination

Sporothrix schenckii (S. schenckii), a ubiquitous thermally dimorphic fungus, is the etiological agent of sporotrichosis, affecting immunocompromised and immunocompetent individuals. Despite current antifungal regimens, sporotrichosis results in prolonged treatment and significant mortality rates in the immunosuppressed population. The innate immune system forms the host's first and primary line of defense against S. schenckii, which has a bi-layered cell wall structure. Many components act as pathogen-associated molecular patterns (PAMPs) in pathogen-host interactions. PAMPs are recognized by pattern recognition receptors (PRRs) such as toll-like receptors, C-type lectin receptors, and complement receptors, triggering innate immune cells such as neutrophils, macrophages, and dendritic cells to phagocytize or produce mediators, contributing to S. schenckii elimination. The ultrastructure of S. schenckii and pathogen-host interactions, including PRRs and innate immune cells, are summarized in this review, promoting a better understanding of the innate immune response to S. schenckii and aiding in the development of protective and therapeutic strategies to combat sporotrichosis.