Aspergillus fumigatus Cell Wall: Current Advances in Structural Elucidation Methods

Being an extracellular organelle, the fungal cell wall (CW) plays a crucial role in fungal biology by providing mechanical strength and protecting from its hostile environment. In pathogenic fungi, their CW is explored with two main objectives: (a) to develop novel antifungal molecules, as the disruption of CW leads to fungal lysis due to osmotic imbalance, and (b) to decipher fungal pathogenesis, as CW is the first fungal structure to interact with the host immune system. Aspergillus fumigatus is an airborne filamentous fungal pathogen, which causes a spectrum of infections ranging from allergic broncho-pulmonary aspergillosis (ABPA), mild aspergilloma (formation of fungal mass in preformed lung cavities, as in post-tuberculosis condition), to life-threatening chronic pulmonary aspergillosis (CPA) and invasive pulmonary aspergillosis (IPA). CPA occurs in those with an underlying lung condition, which facilitates the colonization of A. fumigatus. Whereas immunocompromised hosts are highly susceptible to IPA due to their inability to eliminate inhaled conidia reaching lung alveoli, A. fumigatus life-cycle spans between airborne spores (conidia) and hyphae. Accordingly, its CW undergoes continuous reorganization, leading to compositional changes, which pose difficulties for antifungal drugs to function efficiently or for the host immune system to mount an effective antifungal defense. Therefore, deciphering the organization of A. fumigatus CW during its dynamic state and at the molecular level is essential to study its impact against antifungal drugs and host immune defenses for the better management of aspergillosis. Focusing on these objectives, the current chapter compiles protocols for the extraction of different CW components, their quantification, and the techniques used to study the structural organization of A. fumigatus CW.