Laboratório de Estudos Avançados de Microrganismos Emergentes e Resistentes (LEAMER), Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes (IMPG), Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, Brazil.
Rede Micologia RJ - Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Rio de Janeiro, Brazil.
Braz J Microbiol. 2023 Dec;54(4):2577-2585. doi: 10.1007/s42770-023-01062-7. Epub 2023 Jul 13.
Scedosporium apiospermum is a widespread, emerging, and multidrug-resistant filamentous fungus that can cause localized and disseminated infections. The initial step in the infection process involves the adhesion of the fungus to host cells and/or extracellular matrix components. However, the mechanisms of adhesion involving surface molecules in S. apiospermum are not well understood. Previous studies have suggested that the binding of fungal receptors to fibronectin enhances its ability to attach to and infect host cells. The present study investigated the effects of fibronectin on adhesion events of S. apiospermum. The results revealed that conidial cells were able to bind to both immobilized and soluble human fibronectin in a typically dose-dependent manner. Moreover, fibronectin binding was virtually abolished in trypsin-treated conidia, suggesting the proteinaceous nature of the binding site. Western blotting assay, using fibronectin and anti-fibronectin antibody, evidenced 7 polypeptides with molecular masses ranging from 55 to 17 kDa in both conidial and mycelial extracts. Fibronectin-binding molecules were localized by immunofluorescence and immunocytochemistry microscopies at the cell wall and in intracellular compartments of S. apiospermum cells. Furthermore, a possible function for the fibronectin-like molecules of S. apiospermum in the interaction with host lung cells was assessed. Conidia pre-treated with soluble fibronectin showed a significant reduction in adhesion to either epithelial or fibroblast lung cells in a classically dose-dependent manner. Similarly, the pre-treatment of the lung cells with anti-fibronectin antibodies considerably diminished the adhesion. Collectively, the results demonstrated the presence of fibronectin-binding molecules in S. apiospermum cells and their role in adhesive events.
棘孢木霉是一种广泛存在、新兴且多药耐药的丝状真菌，可引起局部和播散性感染。感染过程的初始步骤涉及真菌与宿主细胞和/或细胞外基质成分的粘附。然而，棘孢木霉中涉及表面分子的粘附机制尚不清楚。先前的研究表明，真菌受体与纤维连接蛋白的结合增强了其附着和感染宿主细胞的能力。本研究调查了纤维连接蛋白对棘孢木霉粘附事件的影响。结果表明，分生孢子细胞能够以典型的剂量依赖性方式结合固定化和可溶性人纤维连接蛋白。此外，在胰蛋白酶处理的分生孢子中，纤维连接蛋白结合几乎被消除，表明结合位点具有蛋白质性质。使用纤维连接蛋白和抗纤维连接蛋白抗体的 Western blot 分析表明，在分生孢子和菌丝体提取物中均存在 7 种分子量在 55 至 17 kDa 之间的多肽。通过免疫荧光和免疫细胞化学显微镜，在棘孢木霉细胞壁和细胞内隔室中定位了纤维连接蛋白结合分子。此外，还评估了棘孢木霉纤维连接蛋白样分子在与宿主肺细胞相互作用中的可能功能。用可溶性纤维连接蛋白预处理的分生孢子在与上皮或成纤维细胞肺细胞的粘附中显示出显著的剂量依赖性降低。同样，用抗纤维连接蛋白抗体预处理肺细胞也大大减少了粘附。总之，这些结果表明棘孢木霉细胞中存在纤维连接蛋白结合分子及其在粘附事件中的作用。
