Galectin-3 Induces Death of Candida Species Expressing Specific β-1,2-Linked Mannans Luciana Kohatsu, Daniel K. Hsu, Armin G. Jegalian, Fu-Tong Liu and Linda G. Baum This information is current as of September 30, 2021. J Immunol 2006; 177:4718-4726; ; doi: 10.4049/jimmunol.177.7.4718 http://www.jimmunol.org/content/177/7/4718 Downloaded from References This article cites 72 articles, 34 of which you can access for free at: http://www.jimmunol.org/content/177/7/4718.full#ref-list-1 Why The JI? Submit online. http://www.jimmunol.org/ • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average by guest on September 30, 2021 Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2006 by The American Association of Immunologists All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Galectin-3 Induces Death of Candida Species Expressing Specific ␤-1,2-Linked Mannans1 Luciana Kohatsu,* Daniel K. Hsu,† Armin G. Jegalian,* Fu-Tong Liu,† and Linda G. Baum2* Lectins play a critical role in host protection against infection. The galectin family of lectins recognizes saccharide ligands on a variety of microbial pathogens, including viruses, bacteria, and parasites. Galectin-3, a galectin expressed by macrophages, dendritic cells, and epithelial cells, binds bacterial and parasitic pathogens including Leishmania major, Trypanosoma cruzi, and Neisseria gonorrhoeae. However, there have been no reports of galectins having direct effects on microbial viability. We found that galectin-3 bound only to Candida albicans species that bear ␤-1,2-linked oligomannans on the cell surface, but did not bind Saccharomyces cerevisiae that lacks ␤-1,2-linked oligomannans. Surprisingly, binding directly induced death of Candida species containing specific ␤-1,2-linked oligomannosides. Thus, galectin-3 can act as a pattern recognition receptor that recognizes a unique pathogen-specific oligosaccharide sequence. This is the first description of antimicrobial activity for a member of the Downloaded from galectin family of mammalian lectins; unlike other lectins of the innate immune system that promote opsonization and phago- cytosis, galectin-3 has direct fungicidal activity against opportunistic fungal pathogens. The Journal of Immunology, 2006, 177: 4718–4726. nfections with opportunistic fungi are a critical health con- isms, including worms, sponges, multicellular fungi, and insects cern; thus, elucidation of different innate immune strategies (13–19). Galectins are PRRs in several types of organisms, and http://www.jimmunol.org/ I to control fungal infections is an important goal. A number of many mammalian pathogens express saccharide structures that are endogenous lectins participate in innate immune responses and are recognized by galectins. Galectin-1 binds saccharide ligands on important for control of microbial infections, especially those envelope glycoproteins of Nipah virus and HIV (20, 21). Galec- caused by fungal pathogens. As pattern-recognition receptors tin-3 and galectin-9 bind Leishmania major and galectin-9 pro- (PRRs),3 lectins recognize unique carbohydrate ligands, or patho- motes L. major-macrophage interactions (22, 23). Galectin-3 binds gen-associated molecular patterns (PAMPs), present on the surface mycolic acids, a major component of the cell envelope of Myco- of the pathogen but absent in the host (1–5). Fungal oligosaccha- bacterium tuberculosis (24), and participates in clearance of late ride PAMPs are recognized by lectin PRRs to induce rapid and mycobacterial infections (25). Galectin-3 also binds Pseudomonas broad host defense responses such as opsonization, activation of aeruginosa, Klebsiella pneumoniae, and Neisseria gonorrhoeae by guest on September 30, 2021 complement, activation of coagulation cascades, phagocytosis, in- (26–28), as well as GalNAc1–4GlcNAc sequences in Schistosoma flammation, and direct microbial killing (3). Engagement of PRRs mansoni soluble egg Ag (29). Galectin-3 mediates adhesion of on macrophages and dendritic cells can also attract, activate, and Trypanosoma cruzi to human vascular smooth muscle cells (30), regulate T cells that are critical for an acquired immune response and expression of human galectin-1 and galectin-3 is up-regulated to fungal pathogens (6). in APCs and gastric epithelial cells infected with T. cruzi and Several types of lectins function as PRRs during the host re- Helicobacter pylori (31–33). Several studies indicate that galec- sponse to fungal infections, including pentraxin-3, dectin-1, and tin-3 specifically participates in innate immunity, as galectin-3 is the collectin family members surfactant proteins A and D (1, expressed in a variety of cell types including dendritic cells, mac- 7–11). Recently, it has become apparent that the galectin family of rophages, and NK cells, as well as activated T and B cells (34–38). lectins can also participate in the innate immune defense against However, while galectin-3 can recognize specific PAMPs, no di- pathogens (12). Galectins are present in all multicellular organ- rect microbicidal function for galectin-3, or any galectin, has been reported. Galectins possess a conserved carbohydrate-recognition domain *Department of Pathology and Laboratory Medicine, Jonsson Comprehensive Cancer (CRD) and typically bind to glycans containing ␤-galactosides Center, School of Medicine, University of California, Los Angeles, CA 90095; and †Department of Dermatology, School of Medicine, University of California Davis, (39). However, subtle structural differences among galectin CRDs Sacramento, CA 95817 result in distinct binding affinities for specific glycan ligands (40). Received for publication February 6, 2006. Accepted for publication July 19, 2006. Galectin-3 has an extended carbohydrate-binding pocket compared The costs of publication of this article were defrayed in part by the payment of page with galectin-1 (41). This structural difference allows galectin-3 to charges. This article must therefore be hereby marked advertisement in accordance bind to a wider range of oligosaccharide structures, including with 18 U.S.C. Section 1734 solely to indicate this fact. structures containing mannose (41). Galectin-3 also differs struc- 1 This work was supported by National Institutes of Health (NIH) Grant AI07323 turally from the other members of the galectin family. The 14 (Microbial Pathogenesis Training Grant) (to L.K.), NIH Grant R01 GM63281 (to L.G.B.), and R01 AI20958 and R01 AI39620 (to F.-T.L.). mammalian galectins are divided into three subgroups, mono- 2 Address correspondence and reprint requests to Dr. Linda G. Baum, Department of meric, tandem repeat, and chimeric, based on domain structure. Pathology and Laboratory Medicine, School of Medicine, University of California Galectin-3 is the only member of the chimera-type galectin sub- Los Angeles School of Medicine, 10833 Le Conte Avenue, Los Angeles, CA 90095. group, with a CRD in the C terminus and a distinct N-terminal E-mail address: [email protected] domain that mediates oligomerization of the lectin into pentamers 3 Abbreviations used in this paper: PRR, pattern recognition receptor; PAMP, patho- gen-associated molecular pattern; CRD, carbohydrate recognition domain; SA, upon binding multivalent saccharide ligands (13, 42, 43). As men- streptavidin; DTAF, (4,6-dichlorotriazinyl) aminofluorescein. tioned above, galectin-3 is highly expressed in macrophages and Copyright © 2006 by The American Association of Immunologists, Inc. 0022-1767/06/$02.00 The Journal of Immunology 4719 immature dendritic cells; expression is up-regulated in activated search Laboratories) by flow cytometry on a BD-LSR I Analytic Flow macrophages and is down-regulated during dendritic cell matura- Cytometer and data were analyzed with CellQuest software (BD Bio- ␮ tion (37, 44). Galectin-3 is also expressed in many types of epi- sciences). For inhibition assays, 22.5 g of galectin-3 was preincubated on ice with 0.1 M ␤-lactose (Sigma-Aldrich), 0.1 M sucrose (Fisher Scien- thelial cells and stromal cells, including fibroblasts after activation tific), 1 mg/ml S. cerevisiae cell wall mannan (Sigma-Aldrich), or 1 mg/ml or adhesion (45, 46). Like all galectins, galectin-3 is made as a C. albicans serotype A cell wall mannan Takara MG001 (Takara Mirus monomer in the cytosol and is secreted from the cytosol via a Bio), before binding to live yeast. nonclassical secretion mechanism; secreted galectin-3 binds to Serotyping of cell surface expression of ␤-1,2-oligomannan multivalent saccharide ligands on cells and extracellular matrix in antigenic factors 5 and 6 the immediate milieu (47–50). Candida check rabbit antisera against antigenic factors 5 (F5) and 6 (F6) Surprisingly, Fradin et al. (51) demonstrated that galectin-3 ␤ ␤ (Iatron Laboratories) that specifically identify distinct Candida -1,2- binds to -1,2-linked oligomannosides, an uncommon PAMP linked oligomannans were used. Rabbit antisera