Neurobasal medium enhances titan cell formation in Cryptococcus spp.

Background: Titan cells in Cryptococcus species play a critical role in fungal virulence by resisting oxidative stress, phagocytosis, and antifungal treatments. Developing reliable methods to induce titan cells is crucial for understanding the mechanisms of Cryptococcus pathogenesis.

Objectives: In this study we report an unexpected discovery of a simple in vitro induction of titan cells in Cryptococcus neoformans and Cryptococcus gattii using Neurobasal™ (NB) medium.

Methods and findings: By employing established in vitro culture methods, we demonstrate a significantly higher capacity for titan cell formation in Cryptococcus spp. Cells grown in complete NB medium exhibited larger cell bodies, increased capsule sizes, and a higher percentage of titan cells compared to those grown in minimal medium (MM). NB medium without the B27 supplement significantly impacted titan cell formation.

Main conclusions: Our findings indicate that NB medium, originally developed for neuronal cell cultures, is a useful tool for studying titan cell biology. This is particularly relevant given the association between titan cells and the central nervous system, highlighting their potential role in Cryptococcus pathogenesis.