Cryptococcus neoformans and the EGFR Puzzle: Uncovering a Novel mechanism for blood-brain barrier crossing.

This study aims to investigate the molecular mechanisms by which Cryptococcus neoformans (C. neoformans) crosses the blood-brain barrier (BBB), focusing specifically on the role of the epidermal growth factor receptor (EGFR) and its ligand, HB-EGF. Cryptococcal meningitis, caused by C. neoformans, has a high mortality rate and poses a significant threat to global public health. Research indicates that C. neoformans employs various strategies to cross the BBB, with transcellular transport being particularly critical. We observed that C. neoformans infection significantly upregulates the expression and phosphorylation of EGFR in brain microvascular endothelial cells (BMECs). Silencing EGFR using siRNA technology resulted in a marked decrease in the ability of C. neoformans to traverse the BMEC monolayer. Furthermore, C. neoformans infection also upregulates EGFR ligands, such as HB-EGF, in BMECs, thereby activating the EGFR signaling pathway. This activation involves the engagement of ADAM family metalloproteinases and the metalloprotease Mpr1 from C. neoformans. The findings of this study underscore the critical role of the host EGFR signaling pathway in the ability of C. neoformans to cross the BBB and highlight potential targets for developing new therapies for infectious meningitis.