Project description:Mucormycosis is an increasingly common, life-threatening fungal infection caused by fungi belonging to the subphylum Mucormycotina, order Mucorales. The major risk factors for mucormycosis include uncontrolled diabetes mellitus, treatment with corticosteroids, organ or bone marrow transplantation, neutropenia, trauma and burns, malignant hematological disorders, and deferoxamine-therapy in patients receiving hemodialysis. Amphotericin B (AmB) remains the only antifungal agent approved for the treatment of invasive mucormycosis. Because fungi belonging to the mucorales order are relatively resistant to AmB, high doses are required, which frequently causes nephrotoxicity and other adverse effects. In the absence of surgical removal of the infected focus (such as excision of the eye in patients with rhinocerebral mucormycosis), antifungal therapy alone is rarely curative. Even when surgical debridement is combined with high-dose AmB, the mortality associated with mucor¬mycosis is >50%. In patients with prolonged neutropenia or disseminated disease, mortality is 90-100%. Rhizopus oryzae is by far the most common organism isolated from patients with mucormycosis, and is responsible for approximately 70% of all cases of mucormycosis. Recent epidemiological data collected from transplant centers have demonstrated a striking increase in the number of reported cases of mucormycosis. Furthermore, mucormycosis outbreaks are also known to follow natural disasters as was the case following the tsunami that devastated Indonesia in 2004 and the tornadoes that destroyed Joplin, Missouri in June 2011. Hence, there exists a large impetus to identify particular virulence factors and biomarkers associated with mucormycosis, which would lead to a rational approach to develop new antifungals and vaccines to prevent deaths specifically due to mucormycosis. In order to better understand the complex nature of the host pathogen interaction during mucormycosis, we performed dual species RNA-seq on 5 different Mucorales strains during in vitro infection of endothelial or epithelial cells.
Project description:Mucormycosis is a life-threatening disease especially in immunocompromised patients that was caused my mucoralean fungi. The rate of mortality is tremendously increased in the last decades due to the lack of appropriate diagnostic tools, insufficient knowledge about the immune response toward the mucormycosis and unavailability of specific antifungal drugs. Several species of mucoralean fungi cause mucormycosis such as Lichtheimia, Rhizopus, and Mucor. Lichtheimia species ranks the second and third cause of mucormycosis in Europe and the USA, respectively. In this study, we investigated the receptors present on the surface of immune cells that bind to the spores of Lichtheimia. We focus on two strains of L. corymbifera (FSU:9682 and FSU:10164) using resting and heat-killed spores. Additionally, we choose alveolar macrophages (MH-S) to carry out our experiment. MH-S is the first line of defense in the lung and the major component in the innate immune system. MH-S surface proteins were biotinylated and incubated with Lichtheimia spores. The surface proteins and putative binding partners were enriched by streptavidin. LC-MS/MS analysis showed that several proteins are highly expressed in presence of Lichtheimia spores, of which the heat shock protein family A (HSPA8) was one of the most abundant proteins. FACS analysis and immunofluorescence examination confirmed that HSPA8 is highly abundant on the surface of the MH-S, but not on the surface of Lichtheimia spores. Moreover, our study showed that the intensity of HSPA8 on the surface of MH-S depends on the multiplicity of infection (MOI). Additionally, the blocking with anti-HSPA8 antibody reduced the capability of MH-S to engulf the Lichtheimia spores, but not Aspergillus fumigatus spores. This confirms that HSPA8 is specific to Lichtheimia. THis is the first study addressing the determination of surface receptors of alveolar macrophages that in the context of Mucoralean fungi.
