Role of the Lewisx Glycan Determinant in Corneal Epithelial Cell Adhesion and Differentiation

Zhiyi Cao, Zheng Zhao, Royce Mohan, Joseph Alroy, Pamela Stanley, Noorjahan Panjwani

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

In this study we demonstrate that in corneal epithelium there is cell-cell contact-regulated expression of a 145-kDa glycoprotein (GP) bearing the glycan determinant Lewisx (Lex) (Galβ(1,4)[Fucα (1,3)]GlcNAc). This glycoprotein (Lex-GP) was expressed in confluent/contact-inhibited cultures but not in sparse cultures of corneal epithelium. In contrast, a 135-kDa glycoprotein bearing precursor, unfucosylated, lactosamine-containing glycans (Galβ1-4GlcNAcβ1-R) was expressed in sparse cultures. Immunofluorescence staining and confocal microscopy of confluent cultures revealed that in corneal epithelium, Le x antigen is located in high density at sites of cell-cell adhesion. In in vitro cell-cell adhesion assays, anti-Lex, but not anti-sialyl-Lex monoclonal antibodies, inhibited the formation of corneal epithelial cell-cell adhesion. Also, when added to confluent cultures, antibodies to Lex disrupted the monolayer and caused tightly packed polygonal cells to round up. Analysis of the expression of Fut genes that encode α-1,3-fucosyltransferases, the enzymes that generate the Le x determinant, revealed that confluent/contact-inhibited cultures of rabbit corneal epithelium contain markedly elevated levels of Fut4 and Fut3/5/6 gene transcripts compared with sparse cultures. These data suggest that the Fut4 and Fut3/5/6 genes are targets of cell-cell contact-regulated signals and that Fut gene products direct cell-cell contact-associated expression of Le x on the Lex-GP in corneal epithelium. Immunohistochemical analysis revealed that the expression of Lex antigen in the epithelium of adult and developing corneas is related to the stage of differentiation of the cells. Although early differentiated cells robustly expressed Lex, relatively undifferentiated cells did not, and the expression level was relatively low in terminally differentiated cells. Overall, these data provide evidence that a Lex-bearing glycoprotein plays a role through the Lex determinant in corneal epithelial cell-cell adhesion, and these data suggest that Lex-mediated cell-cell interactions contribute to mechanisms that mediate corneal epithelial cell differentiation.

Original languageEnglish (US)
Pages (from-to)21714-21723
Number of pages10
JournalJournal of Biological Chemistry
Volume276
Issue number24
DOIs
StatePublished - Jun 15 2001

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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