Abstract
The composition of the mucus gel of the tear film reflects the competing needs for transparency, stability, hydration, and protection of the ocular surface. Mucins form the macromolecular scaffolding of this hydrated gel, and glycans decorating these glycoproteins represent a rich source of binding ligands that may both modulate microbial binding and regulate the physicochemical characteristics of the gel. This study compares the structure of O-linked glycans derived from the ocular mucins of three species, to determine whether the ocular surface microenvironment dictates the need for a common pattern of O-linked carbohydrate structures. Ocular mucus aspirates were collected from healthy humans, rabbits and dogs. Mucins were purified using standard protocols. O-glycans were released by hydrazinoloysis and subsequently analysed by a combination of HPLC, exoglycosidase digestions and LC–MS/MS. A total of 12 different O-glycans were identified. In human ocular mucin, the majority were negatively charged and terminated in sialic acid, whilst those from rabbit or dog were mainly neutral and terminated in α 1-2 fucose and/or α 1-3 N-acetylgalactosamine. The glycans were short: the most common structures being tetra-, tri- or disaccharides. Less elaborate glycan structures are encountered at the ocular surface than at many other mucosal surfaces. Species-specific glycan expression is a feature of ocular surface mucins, and has implications for their defensive properties where different microbial and environmental challenges are encountered.
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Corfield, A., Carrington, S., Hicks, S., Berry, M., Ellingham, R.: Ocular mucins: purification, metabolism and functions. Prog. Retin. Eye Res. 16, 627–656 (1997)
Gipson, I.K., Hori, Y., Argüeso, P.: Character of ocular surface mucins and their alteration in dry eye disease. Ocul. Surf. 2, 131–148 (2004)
Berry, M., Brayshaw, D., McMaster, T.J.: Dynamic molecular resolution imaging of preocular fluid impressions. Br. J. Ophthalmol. 88, 1460–1466 (2004)
Fleiszig, S.M., McNamara, N.A., Evans, D.J.: The tear film and defense against infection. Adv. Exp. Med. Biol. 506, 523–530 (2002)
Hang, H.C., Bertozzi, C.R.: The chemistry and biology of mucin-type O-linked glycosylation. Bioorg. Med. Chem. 13, 5021–5034 (2005)
Paulsen, F.P., Berry, M.S.: Mucins and TFF peptides of the tear film and lacrimal apparatus. Prog. Histochem. Cytochem. 41, 1–53 (2006)
Gipson, I.K.: Distribution of mucins at the ocular surface. Exp. Eye Res. 78, 379–388 (2004)
Gipson, I.K., Inatomi, T.: Cellular origin of mucins of the ocular surface tear film. Adv. Exp. Med. Biol. 438, 221–227 (1998)
Corfield, A.P., Carroll, D., Myerscough, N., Probert, C.S.: Mucins in the gastrointestinal tract in health and disease. Front. Biosci. 6, D1321–D1357 (2001)
Rose, M.C., Voynow, J.A.: Respiratory tract mucin genes and mucin glycoproteins in health and disease. Physiol. Rev. 86, 245–278 (2006)
Lamblin, G., Aubert, J.P., Perini, J.M., et al.: Human respiratory mucins. Eur. Respir. J. 5, 247–256 (1992)
Hollingsworth, M.A., Swanson, B.J.: Mucins in cancer: protection and control of the cell surface. Nat. Rev. Cancer 4, 45–60 (2004)
Bell, S.L., Xu, G., Khatri, I.A., Wang, R., Rahman, S., Forstner, J.F.: N-linked oligosaccharides play a role in disulphide-dependent dimerization of intestinal mucin Muc2. Biochem. J. 373, 893–900 (2003)
Gipson, I.K., Argueso, P.: Role of mucins in the function of the corneal and conjunctival epithelia. Int. Rev. Cytol. 231, 1–49 (2003)
Hanisch, F.G.: O-glycosylation of the mucin type. Biol. Chem. 382, 143–149 (2001)
Varki, A.: Biological roles of oligosaccharides: all of the theories are correct. Glycobiology 3, 97–130 (1993)
Gagneux, P., Varki, A.: Evolutionary considerations in relating oligosaccharide diversity to biological function. Glycobiology 9, 747–755 (1999)
Dennis, J.W., Granovsky, M., Warren, C.E.: Protein glycosylation in development and disease. Bioessays 21, 412–421 (1999)
Drickamer, K., Taylor, M.E.: Evolving views of protein glycosylation. Trends Biochem. Sci. 23, 321–324 (1998)
Hazlett, L., Rudner, X., Masinick, S., Ireland, M., Gupta, S.: In the immature mouse, Pseudomonas aeruginosa pili bind a 57-kd (alpha 2-6) sialylated corneal epithelial cell surface protein: a first step in infection. Invest. Ophthalmol. Vis. Sci. 36, 634–643 (1995)
Rudner, X.L., Zheng, Z., Berk, R.S., Irvin, R.T., Hazlett, L.D.: Corneal epithelial glycoproteins exhibit Pseudomonas aeruginosa pilus binding activity. Invest. Ophthalmol. Vis. Sci. 33, 2185–2193 (1992)
Fleiszig, S.M., Zaidi, T.S., Pier, G.B.: Mucus and Pseudomonas aeruginosa adherence to the cornea. Adv. Exp. Med. Biol. 350, 359–362 (1994)
Chen, C.P., Song, S.C., Gilboa-Garber, N., Chang, K.S., Wu, A.M.: Studies on the binding site of the galactose-specific agglutinin PA-IL from Pseudomonas aeruginosa. Glycobiology 8, 7–16 (1998)
Gilboa-Garber, N.: Pseudomonas aeruginosa lectins as a model for lectin production, properties, applications and functions. Zentralbl. Bakteriol. Mikrobiol. Hyg. [A] 270, 3–15 (1988)
Wenneras, C., Neeser, J.R., Svennerholm, A.M.: Binding of the fibrillar CS3 adhesin of enterotoxigenic Escherichia coli to rabbit intestinal glycoproteins is competitively prevented by GalNAc beta 1-4Gal-containing glycoconjugates. Infect. Immun. 63, 640–646 (1995)
Stins, M.F., Prasadarao, N.V., Ibric, L., Wass, C.A., Luckett, P., Kim, K.S.: Binding characteristics of S fimbriated Escherichia coli to isolated brain microvascular endothelial cells. Am. J. Pathol. 145, 1228–1236 (1994)
Sharon, N., Lis, H.: Microbial lectins and their receptors. In: Montreuil, J., Vliegenthart, J.F.G., Schachter, H. (eds.) Glycoproteins II, pp. 475–506. Elsevier, Amsterdam (1997)
Carrington, S.D., Hicks, S.J., Corfield, A.P., et al.: Structural analysis of secreted ocular mucins in canine dry eye. Adv. Exp. Med. Biol. 438, 253–263 (1998)
Berry, M., Ellingham, R.B., Corfield, A.P.: Polydispersity of normal human conjunctival mucins. Invest. Ophthalmol. Vis. Sci. 37, 2559–2571 (1996)
Argueso, P., Herreras, J.M., Calonge, M., Citores, L., Pastor, J.C., Girbes, T.: Analysis of human ocular mucus: effects of neuraminidase and chitinase enzymes. Cornea 17, 200–207 (1998)
Chao, C.C., Butala, S.M., Herp, A.: Studies on the isolation and composition of human ocular mucin. Exp. Eye Res. 47, 185–196 (1988)
Hicks, S.J., Carrington, S.D., Kaswan, R.L., Adam, S., Bara, J., Corfield, A.P.: Demonstration of discrete secreted and membrane-bound ocular mucins in the dog. Exp. Eye Res. 64, 597–607 (1997)
Ellingham, R.B., Berry, M., Stevenson, D., Corfield, A.P.: Secreted human conjunctival mucus contains MUC5AC glycoforms. Glycobiology 9, 1181–1189 (1999)
Royle, L., Mattu, T.S., Hart, E., et al.: An analytical and structural database provides a strategy for sequencing O-glycans from microgram quantities of glycoproteins. Anal. Biochem. 304, 70–90 (2002)
Patel, T., Bruce, J., Merry, A., et al.: Use of hydrazine to release in intact and unreduced form both N- and O-linked oligosaccharides from glycoproteins. Biochemistry 32, 679–693 (1993)
Merry, A.H., Neville, D.C., Royle, L., et al.: Recovery of intact 2-aminobenzamide-labeled O-glycans released from glycoproteins by hydrazinolysis. Anal. Biochem. 304, 91–99 (2002)
Garcher, C., Bara, J., Bron, A., Oriol, R.: Expression of mucin peptide and blood group ABH- and Lewis-related carbohydrate antigens in normal human conjunctiva. Invest. Ophthalmol. Vis. Sci. 35, 1184–1191 (1994)
Berry, M., Corfield, A.P., Harris, A., Khan-Lim, D.: Functional processing of ocular mucins. Adv. Exp. Med. Biol. 506, 283–288 (2002)
Aknin, M.-L.R., Berry, M., Dick, A., Khan-Lim, D.: Normal but not altered mucins activate neutrophils. Cell Tissue Res. 318, 545–551 (2004)
Varki, A., Angata, T.: Siglecs—the major subfamily of I-type lectins. Glycobiology 16, 1R–27R (2006)
Sperandio, M.: Selectins and glycosyltransferases in leukocyte rolling in vivo. FEBS J. 273, 4377–4389 (2006)
Varki, A.: Sialic acids as ligands in recognition phenomena. FASEB J. 11, 248–255 (1997)
Hirmo, S., Kelm, S., Schauer, R., Nilsson, B., Wadstrom, T.: Adhesion of Helicobacter pylori strains to alpha-2,3-linked sialic acids. Glycoconj. J. 13, 1005–1011 (1996)
Angata, T., Varki, A.: Chemical diversity in the sialic acids and related alpha-keto acids: an evolutionary perspective. Chem. Rev. 102, 439–469 (2002)
Kelm, S., Schauer, R.: Sialic acids in molecular and cellular interactions. Int. Rev. Cytol. 175, 137–240 (1997)
Hooper, L.V., Gordon, J.I.: Glycans as legislators of host–microbial interactions: spanning the spectrum from symbiosis to pathogenicity. Glycobiology 11, 1R–10R (2001)
Gagneux, P., Cheriyan, M., Hurtado-Ziola, N., et al.: Human-specific regulation of alpha 2-6-linked sialic acids. J. Biol. Chem. 278, 48245–48250 (2003)
Alexander, D.A., Dimock, K.: Sialic acid functions in enterovirus 70 binding and infection. J. Virol. 76, 11265–11272 (2002)
Olofsson, S., Kumlin, U., Dimock, K., Arnberg, N.: Avian influenza and sialic acid receptors: more than meets the eye? Lancet Infect. Dis. 5, 184–188 (2005)
Wu, E., Fernandez, J., Fleck, S.K., Von Seggern, D.J., Huang, S., Nemerow, G.R.: A 50-kDa membrane protein mediates sialic acid-independent binding and infection of conjunctival cells by adenovirus type 37. Virology 279, 78–89 (2001)
Aristoteli, L.P., Willcox, M.D.: The adhesion of Pseudomonas aeruginosa to high molecular weight human tear film species corresponds to glycoproteins reactive with Sambucus nigra lectin. Exp. Eye Res. 83, 1146–1153 (2006)
Sack, R.A., Beaton, A., Sathe, S., Morris, C., Willcox, M., Bogart, B.: Towards a closed eye model of the pre-ocular tear layer. Prog. Retin. Eye Res. 19, 649–668 (2000)
Sack, R.A., Nunes, I., Beaton, A., Morris, C.: Host-defense mechanism of the ocular surfaces. Biosci. Rep. 21, 463–480 (2001)
Sack, R.A., Bogart, B.I., Beaton, A., Sathe, S., Lew, G.: Diurnal variations in tear glycoproteins: evidence for an epithelial origin for the major non-reducible > or =450 kDa sialoglycoprotein(s). Curr. Eye Res. 16, 577–588 (1997)
Jass, J.R., Smith, M.: Sialic acid and epithelial differentiation in colorectal polyps and cancer—a morphological, mucin and lectin histochemical study. Pathology 24, 233–242 (1992)
Corfield, A.P., Wagner, S.A., Clamp, J.R., Kriaris, M.S., Hoskins, L.C.: Mucin degradation in the human colon: production of sialidase, sialate O-acetylesterase, N-acetylneuraminate lyase, arylesterase, and glycosulfatase activities by strains of fecal bacteria. Infect. Immun. 60, 3971–3978 (1992)
Corfield, A.P., Donapaty, S.R., Carrington, S.D., Hicks, S.J., Schauer, R., Kohla, G.: Identification of 9-O-acetyl-N-acetylneuraminic acid in normal canine pre-ocular tear film secreted mucins and its depletion in Keratoconjunctivitis sicca. Glycoconj. J. 22, 409–416 (2005)
Argueso, P., Sumiyoshi, M.: Characterization of a carbohydrate epitope defined by the monoclonal antibody H185: sialic acid O-acetylation on epithelial cell-surface mucins. Glycobiology 16, 1219–1228 (2006)
Prado, M.R., Rocha, M.F., Brito, E.H., et al.: Survey of bacterial microorganisms in the conjunctival sac of clinically normal dogs and dogs with ulcerative keratitis in Fortaleza, Ceara, Brazil. Vet. Ophthalmol. 8, 33–37 (2005)
Cooper, S.C., McLellan, G.J., Rycroft, A.N.: Conjunctival flora observed in 70 healthy domestic rabbits (Oryctolagus cuniculus). Vet. Rec. 149, 232–235 (2001)
McDonald, P., Watson, A.: Microbial flora of normal canine conjunctivae. J. Small Anim. Pract. 17, 809–812 (1976)
Urban, M., Wyman, M., Rheins, M., Marraro, R.: Conjunctival flora of clinically normal dogs. J. Am. Vet. Med. Assoc. 161, 201–207 (1972)
Deeb, B.J., DiGiacomo, R.F.: Respiratory diseases of rabbits. Vet. Clin. North Am. Exot. Anim. Pract. 3, 465–480 (2000), vi–vii
Loliger, H.C., Matthes, S.: Infectious factor diseases in domestic small animals (carnivorous and herbivorous fur animals, wool and meat rabbits. Berl. Munch. Tierarztl. Wochenschr. 102, 364–371 (1989)
McNamara, N.A., Andika, R., Kwong, M., Sack, R.A., Fleiszig, S.M.: Interaction of Pseudomonas aeruginosa with human tear fluid components. Curr. Eye Res. 30, 517–525 (2005)
Fleiszig, S.M., Zaidi, T.S., Ramphal, R., Pier, G.B.: Modulation of Pseudomonas aeruginosa adherence to the corneal surface by mucus. Infect. Immun. 62, 1799–1804 (1994)
Rhim, A.D., Stoykova, L., Glick, M.C., Scanlin, T.F.: Terminal glycosylation in cystic fibrosis (CF): a review emphasizing the airway epithelial cell. Glycoconj. J. 18, 649–659 (2001)
Trivier, D., Houdret, N., Courcol, R.J., Lamblin, G., Roussel, P., Davril, M.: The binding of surface proteins from Staphylococcus aureus to human bronchial mucins. Eur. Respir. J. 10, 804–810 (1997)
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The authors acknowledge the support of The Oxford Glycobiology Institute Endowment, and Brian Matthews for his expert assistance with the hydrazinolysis procedures, and Sally Hicks for help with Mucin purification.
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Louise Royle and Elizabeth Matthews contributed equally to this work.
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Royle, L., Matthews, E., Corfield, A. et al. Glycan structures of ocular surface mucins in man, rabbit and dog display species differences. Glycoconj J 25, 763–773 (2008). https://doi.org/10.1007/s10719-008-9136-6
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DOI: https://doi.org/10.1007/s10719-008-9136-6