Biotinylated surfome profiling identifies potential biomarkers for diagnosis and therapy ofAspergillus fumigatusinfection

Abstract

12Aspergillus fumigatus is one of the most common airborne fungi capable of causing invasive 13 mycoses in immunocompromised patients and allergic diseases in susceptible individuals. In 14 both cases, fungal surface proteins mediate the first contact with the human immune system to 15 evade immune responses or to induce hypersensitivity. Several methods have been established to 16 study the surface proteome (surfome) of A. fumigatus, like trypsin shaving, glucanase treatment, 17• By comparison with other surfome datasets, a core surfome of A. fumigatus was defined, 40 which provides possible biomarkers for diagnosis or therapy. 41 SIGNIFICANCE 42Aspergillus fumigatus is the most important airborne human pathogenic mold, capable of 43 causing both life-threatening invasive pulmonary aspergillosis in immunocompromised patients 44 and allergic infections in atopic individuals. Despite its obvious medical relevance, timely 45 diagnosis and efficient antifungal treatment of A. fumigatus infection remains a major challenge. 46Proteins on the surface of conidia (asexually produced spores) and mycelium directly mediate 47 host-pathogen interaction and also may serve as targets for diagnosis and immunotherapy. 48However, the similarity of protein sequences between A. fumigatus and other organisms, and 49 sometimes even the human host, makes selection of targets for immunological-based studies 50 difficult. Here, using surface protein biotinylation coupled with LC-MS/MS analysis, we 51 identified hundreds of A. fumigatus surface proteins with exposed regions, further defining 52 putative targets for possible diagnostic and immunotherapeutic design. 53 KEYWORDS 54Aspergillus fumigatus, surface biotinylation, surfome, LC-MS/MS, allergens, heat shock protein. 55 immunocompromised patients, chronic pulmonary aspergillosis in immunocompetent patients 60 with underlying lung diseases, or allergic infections such as allergic bronchopulmonary 61 aspergillosis (ABPA) in atopic individuals [3, 4]. Despite continuous research and improvements 62 of diagnostic tools, timely diagnosis of A. fumigatus remains a challenge [2]. Detection kits for a 63 few different recombinant allergens of A. fumigatus are now commercially available for the 64 diagnosis of ABPA, but cross-reactivity with antigens from other microorganisms still makes 65 diagnosis difficult [5]. In addition to DNA and cell wall polysaccharides, fungal proteins 66 exposed to the surface may serve as candidate diagnostic markers and valuable targets for new 67 therapeutics [6, 7]. 68The A. fumigatus cell wall not only maintains cellular integrity and protects from external 69 aggression, but it also serves as a harbor for virulence factors that contribute to immune evasion, 70 adherence, and virulence [8]. Although the cell wall is composed of <10% proteins [2] and 71 hundreds of surface proteins have been detected across various proteome studies [9][10][11], only a 72 few of these proteins are well characterized, including their roles in A. fumigatus virulence. 73RodA, whi...