The Sweet Side of Fungal Infections: Structural Glycan Diversity and Its Importance for Pathogenic Adaptation

Abstract

Fungal infections are the most common secondary infections in debilitated individuals in a state of chronic disease or immunosuppression. Despite this, most fungal infections are neglected, mainly due to the lower frequency of their more severe clinical forms in immunocompetent individuals with a healthy background. However, over the past few years, several cases of severe fungal infections in healthy individuals have provoked a change in the epidemiological dynamics of fungal infections around the world, both due to recurrent outbreaks in previously infrequent regions and the greater emergence of more pathogenic fungal variants affecting healthy individuals, such as in the Cryptococcus genus. Therefore, before the arrival of a scenario of prevalent severe fungal infections, it is necessary to assess more carefully what are the real reasons for the increased incidence of fungal infection globally. What are the factors that are currently contributing to this new possible epidemiological dynamic? Could these be of a structural nature? Herein, we propose a discussion based on the importance of the virulence factors of glycoconjugate composition in the adaptation of pathogenic fungal species into the current scenario of increasing severity of these infections.

Bittersweet Sugars: How Unusual Glycan Structures May Connect Epithelial-to-Mesenchymal Transition and Multidrug Resistance in Cancer

“…On the other hand, the term glycomics refers to the studies that define the collection of glycans exhibited by a single cell or tissue given specific conditions, while glycoproteomics gives us the structure and location of glycan structures in the structure of a given protein [ 1 , 2 ]. Since the expression of glycoconjugates is a hallmark of all living cells, several research groups around the world are interested in understanding the biological role of different classes of glycomolecules, in both physiological and pathological conditions [ 3 , 4 ]. Over the last fifteen years, several important alterations in the expression of glycosyltransferases have been described.…”

Cryptococcus: History, Epidemiology and Immune Evasion

“…Interestingly, morphological characteristics in the capsular dimension of C. gattii are associated with the greater virulence of this species in relation to others of the genus Cryptococcus, since it has the ability to change its size during infection, facilitating its intracellular life stage and passage through the blood-brain barrier [125]. Clearly, virulence factors of glycoconjugate composition are proposed to be crucial for adaptation of pathogenic fungal species, such as in the Cryptococcus genus [126].…”

Pulmonary Fibrosis and Hypereosinophilia in TLR9-/- Mice Infected by Cryptococcus gattii

“…C. gattii and C. neoformans yeasts are the only pathogenic encapsulated fungi. Glucuronoxylomannan (GXM) and glucuronoxylomannogalactan (GXMGal) polysaccharides are the main components of the capsule that covers the yeast and represent two of the most important virulence factors, although other virulence factors such as melanin production, abnormally sized yeast (titan cells), vesicle release and growth at 37 • C are also important and well-described in the literature [7][8][9][10][11][12][13]. The transmission can occur through the inhalation of basidiospores or yeast cells that are easily deposited in the alveoli, initially damaging the respiratory system and being able to spread to other organs, such as the brain [1][2][3].…”