Fungal cell envelope and keratinized tissue

The fungal cell envelope is a complex, multi-layered structure consisting of an inner plasma membrane and an outer cell wall, providing essential structural integrity and protection for fungal pathogens (Gow et al., 2017). The cell wall is primarily composed of chitin, glucans (such as beta-1,3-glucan), and mannoproteins, which are absent in human cells, making them ideal therapeutic targets (Garcia-Rubio et al., 2020). The plasma membrane contains ergosterol, a sterol unique to fungi that maintains membrane fluidity and is the target of many clinical antifungals (Odds et al., 2003). Keratinized tissues, including the skin's stratum corneum, hair, and nails, serve as the primary site of infection for dermatophytes, which utilize keratin as a nutrient source (StatPearls, 2023). Therapeutic strategies often target the biosynthesis of the fungal cell envelope to induce cell lysis or growth inhibition in these tissues. For example, allylamines like terbinafine and azoles like itraconazole inhibit ergosterol synthesis, while echinocandins disrupt cell wall formation by inhibiting 1,3-beta-glucan synthase (Nett & Andes, 2016). Griseofulvin specifically targets fungal mitosis and is often used for infections of keratinized structures like hair and nails (Bhattacharya et al., 2016). Understanding the interaction between fungal structures and host keratinized tissue is crucial for treating superficial and systemic mycoses effectively.

Other names

Fungal cell wallFungal cell membraneStratum corneumKeratinous substrateFungal integument

Antifungal agents target the fungal cell envelope by inhibiting the synthesis of essential components like ergosterol (azoles, allylamines) or beta-1,3-glucan (echinocandins), or by directly binding to and disrupting the cell membrane (polyenes). Drugs like griseofulvin interact with fungal microtubules to inhibit mitosis, while others like ciclopirox chelate polyvalent cations to disrupt fungal enzymes. These actions lead to cell lysis or growth arrest within the host's keratinized tissues.