Natural killer cells are pivotal for in vivo protection following systemic infection by Sporothrix schenckii

Inflammation and epigenetics of sporotrichosis disease

Sporotrichosis, a fungal disease, is caused by exposure to soil that harbors Sporothrix schenckii or through inhalation of fungal spores. Skin is the most frequently exposed organ making sporotrichosis a primarily dermal disease. Many described reports in the literature suggest a connection of sporotrichosis with cutaneous squamous cell carcinoma with some connection between initial sporotrichosis diagnosis and treatment followed by development of cutaneous squamous cell carcinoma at the very site. Conversely, there is also evidence for sporotrichosis subsequent to skin cancer diagnosis, even after cancer chemotherapy, which points towards weakening of immune response by cancer chemotherapy leading to attack and infection by Sporothrix schenckii. We also propose and focus on inflammation as the connection between sporotrichosis, cancer and even the metastatic spread of cancer. Inflammation-associated IL-6, IFN-γ, natural killer cells and M2-macrophages possibly mechanistically link sporotrichosis with cancer, particularly cutaneous squamous cell carcinoma. These inflammation related factors/cells are regulated epigenetically raising the possibility of epigenetic regulation of sporotrichosis, which has not been described yet in the available literature. Clinical management of inflammation may thus be effective strategy not just against sporotrichosis but also the related onset of cutaneous squamous cell carcinoma and possibly its metastasis to lymph nodes.

Differential Recognition of Clinically Relevant Sporothrix Species by Human Granulocytes

Sporotrichosis is a cutaneous mycosis that affects humans and animals and has a worldwide distribution. This infection is mainly caused by Sporothrix schenckii, Sporothrix brasiliensis, and Sporothrix globosa. Current research about anti-Sporothrix immunity has been mainly focused on S. schenckii and S. brasiliensis, using different types of human or animal immune cells. Granulocytes are a group of cells relevant for cytokine production, with the capacity for phagocytosis and the generation of neutrophil extracellular traps (NETs). Considering their importance, this study aimed to compare the capacity of human granulocytes to stimulate cytokines, uptake, and form NETs when interacting with different Sporothrix species. We found that conidia, germlings, and yeast-like cells from S. schenckii, S. brasiliensis, and S. globosa play an important role in the interaction with these immune cells, establishing morphology- and species-specific cytokine profiles. S. brasil-iensis tended to stimulate an anti-inflammatory cytokine profile, whilst the other two species had a proinflammatory one. S. globosa cells were the most phagocytosed cells, which occurred through a dectin-1-dependent mechanism, while the uptake of S. brasiliensis mainly occurred via TLR4 and CR3. Cell wall N-linked and O-linked glycans, along with β-1,3-glucan, played a significant role in the interaction of these Sporothrix species with human granulocytes. Finally, this study indicates that conidia and yeast-like cells are capable of inducing NETs, with the latter being a better stimulant. To the best of our knowledge, this is the first study that reports the cytokine profiles produced by human granulocytes interacting with Sporothrix cells.

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.

Sporothrix schenckii regulates macrophage inflammatory responses via the c-JUN-induced Dab2 transcription

Macrophages, which serve as a bridge between innate and adaptive immunity, play an important role in sporotrichosis. Sporothrix schenckii infections can produce immune responses such as macrophage polarization and inflammatory factor secretion. In the early stages of inflammation, the expression of DAB2 in macrophages is increased, which controls the secretion of inflammatory factors and affects the polarization of macrophages. However, the expressions and mechanisms of DAB2 in sporotrichosis are not clear. In this study, we examined the expression of DAB2 and its regulation of inflammatory factors under conditions of Sporothrix schenckii infection. Our results indicated that the Sporothrix schenckii infection increased the expression of DAB2 and revealed a mixed M1/M2-like type of gene expression in BMDMs with the inhibited Il6, Il1β and Arg1, and induced Tnfα, Il10 and Mgl1. The deficiency of Dab2 gene suspended the changes of cytokines. In addition, JNK activity in BMDMs was inhibited by Sporothrix schenckii infection, leading to an increase in c-JUN. We also identified c-JUN as a transcription factor for Dab2 through chromatin immunoprecipitation and luciferase reporter assays. In an in vivo mouse model, sporotrichosis induced skin lesions were accompanied with an upregulation of c-JUN and inhibition of JNK activity, which were in accord with findings from in vitro experiments. Taken together, these findings indicate that in the early stages of Sporothrix schenckii infection there is a promotion of DAB2 expression through the JNK/c-JUN pathway, effects which can then control the expression of inflammatory factors.

Investigation of Obesity-Alleviation Effect of Eurycoma longifolia on Mice Fed with a High-Fat Diet through Metabolomics Revealed Enhanced Decomposition and Inhibition of Accumulation of Lipids

The metabolic and bioactivity effects of Eurycoma longifolia (Eucalyptus longifolia) in obesity treatment were studied in mice fed with a high-fat diet using a metabolomics approach. Aqueous extracts of E. longifolia were obtained via grinding, dissolving, and freeze-drying. The hepatic steatosis effect of E. longifolia was characterized by hematoxylin and eosin histological staining. External performance of the obesity-alleviation effect was monitored by measuring body and food weight. In addition, the metabolomics analysis of the E. longifolia-mice interaction system was performed using the established platform combining liquid chromatography-tandem mass spectrometry with statistical analysis. The presence and spatial distribution patterns of differential molecules were further evaluated through desorption electrospray ionization-mass spectrometry imaging. The results showed that E. longifolia played a vital role in downregulating lipid accumulation (especially triacylglycerols) and fatty acids biosynthesis together with enhanced lipid decomposition and healing in Bagg albino mice. During such a process, E. longifolia mainly induced metabolomic alterations of amino acids, organic acids, phospholipids, and glycerolipids. Moreover, under the experimental concentrations, E. longifolia induced more fluctuations of aqueous-soluble metabolites in the plasma and lipids in the liver than in the kidneys. This study provides an advanced alternative to traditional E. longifolia-based studies for evaluating the metabolic effects and bioactivity of E. longifolia through metabolomics technology, revealing potential technological improvement and clinical application.