Department of Biochemistry and Immunology, Ribeirao Preto Medical School, University of Sao Paulo, Ribeirao Preto, SP, 14049-900, Brazil.
Department of Microbiology and Immunology, Albert Einstein College of Medicine, Yeshiva University, New York, NY, 10461, USA.
Nat Commun. 2017 Dec 6;8(1):1968. doi: 10.1038/s41467-017-02126-7.
Cryptococcus neoformans is an encapsulated fungal pathogen that causes cryptococcosis, which is a major opportunistic infection in immunosuppressed individuals. Mammalian β-galactoside-binding protein Galectin-3 (Gal-3) modulates the host innate and adaptive immunity, and plays significant roles during microbial infections including some fungal diseases. Here we show that this protein plays a role also in C. neoformans infection. We find augmented Gal-3 serum levels in human and experimental infections, as well as in spleen, lung, and brain tissues of infected mice. Gal-3-deficient mice are more susceptible to cryptococcosis than WT animals, as demonstrated by the higher fungal burden and lower animal survival. In vitro experiments show that Gal-3 inhibits fungal growth and exerts a direct lytic effect on C. neoformans extracellular vesicles (EVs). Our results indicate a direct role for Gal-3 in antifungal immunity whereby this molecule affects the outcome of C. neoformans infection by inhibiting fungal growth and reducing EV stability, which in turn could benefit the host.
新型隐球菌是一种囊状真菌病原体,可引起隐球菌病,这是免疫抑制个体中主要的机会性感染。哺乳动物 β-半乳糖苷结合蛋白半乳糖凝集素-3(Gal-3)调节宿主先天和适应性免疫,在包括某些真菌感染在内的微生物感染中发挥重要作用。在这里,我们表明该蛋白在新型隐球菌感染中也发挥作用。我们发现人类和实验性感染以及感染小鼠的脾脏、肺和脑组织中的 Gal-3 血清水平升高。Gal-3 缺陷型小鼠比 WT 动物更容易感染隐球菌病,这表现为真菌负荷更高,动物存活率更低。体外实验表明 Gal-3 抑制真菌生长并对新型隐球菌细胞外囊泡(EVs)发挥直接裂解作用。我们的结果表明 Gal-3 在抗真菌免疫中发挥直接作用,通过抑制真菌生长和降低 EV 稳定性来影响新型隐球菌感染的结果,从而使宿主受益。