Toll-like receptor 4 and CD11b expressed on microglia coordinate eradication of Candida albicans cerebral mycosis

• DOI: 10.1016/j.celrep.2023.113240
• Publication Date: 2023-10-17T09:29:41Z
• Authors: Yifan Wu; Shuqi Du; Lynn H. Bimler; Kelsey E. Mauk; Léa Lortal; Nessim Kichik; James S. Griffiths; Radim Osicka; Lizhen Song; Katherine Polsky; Lydia Kasper; Peter Sebo; Jill Weatherhead; J. Morgan Knight; Farrah Kheradmand; Hui Zheng; Jonathan P. Richa...; Bernhard Hube; Julian R. Naglik; David B. Corry
• Keywords: Medical Sciences; Amyloid beta-Peptides; CD11b Antigen; QH301-705.5; Medical Immunology; 610; Diseases; CP: Immunology; Article; 3. Good health; Fungal Proteins; Toll-Like Receptor 4; Mice; Immune System Diseases; Mycoses; Alzheimer Disease; Allergy and Immunology; CP: Neuroscience; 616; Candida albicans; Medical Specialties; Medicine and Health Sciences; Animals; Microglia; Biology (General)

The fungal pathogen Candida albicans is linked to chronic brain diseases such as Alzheimer's disease (AD), but the molecular basis of brain anti-Candida immunity remains unknown. We show that C. albicans enters the mouse brain from the blood and induces two neuroimmune sensing mechanisms involving secreted aspartic proteinases (Saps) and candidalysin. Saps disrupt tight junction proteins of the blood-brain barrier (BBB) to permit fungal brain invasion. Saps also hydrolyze amyloid precursor protein (APP) into amyloid β (Aβ)-like peptides that bind to Toll-like receptor 4 (TLR4) and promote fungal killing in vitro while candidalysin engages the integrin CD11b (Mac-1) on microglia. Recognition of Aβ-like peptides and candidalysin promotes fungal clearance from the brain, and disruption of candidalysin recognition through CD11b markedly prolongs C. albicans cerebral mycosis. Thus, C. albicans is cleared from the brain through innate immune mechanisms involving Saps, Aβ, candidalysin, and CD11b.