Inhibition of RhoA Prevents Cryptococcus neoformans Capsule Glucuronoxylomannan-Stimulated Brain Endothelial Barrier Disruption

Abstract Cryptococcus neoformans (Cn) is an opportunistic fungus that causes severe central nervous system (CNS) disease in immunocompromised individuals. Brain parenchyma invasion requires fungal traversal of the blood-brain barrier. In this study, we describe that Cn alters the brain endothelium by activating small GTPase RhoA, causing reorganization of the actin cytoskeleton and tight junction modulation to regulate endothelial barrier permeability. We confirm that the main fungal capsule polysaccharide glucuronoxylomannan is responsible for these alterations. We reveal a therapeutic benefit of RhoA inhibition by CCG-1423 in vivo. RhoA inhibition prolonged survival and reduced fungal burden in a murine model of disseminated cryptococcosis, supporting the therapeutic potential of targeting RhoA in the context of cryptococcal infection. We examine the complex virulence of Cn in establishing CNS disease, describing cellular components of the brain endothelium that may serve as molecular targets for future antifungal therapies to alleviate the burden of life-threatening cryptococcal CNS infection. We demonstrate a potential therapeutic benefit of CCG-1423, a RhoA signaling inhibitor, in mice infected with the encapsulated and neurotropic fungus Cryptococcus neoformans. CCG-1423 interferes with capsular polysaccharide–mediated endothelial barrier permeability, thereby reducing fungal central nervous system invasion and prolonging mouse survival.