NEU1 Sialidase Regulates the Sialylation State of CD31 and Disrupts CD31-driven Capillary-like Tube Formation in Human Lung Microvascular Endothelia

• Published in: The Journal of biological chemistry Vol. 289; no. 13; pp. 9121 - 9135
• Main Authors: Lee, Chunsik, Liu, Anguo, Miranda-Ribera, Alba, Hyun, Sang Won, Lillehoj, Erik P., Cross, Alan S., Passaniti, Antonino, Grimm, P.Richard, Kim, Bo-Young, Welling, Paul A., Madri, Joseph A., DeLisser, Horace M., Goldblum, Simeon E.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 28-03-2014; American Society for Biochemistry and Molecular Biology
• Subjects: Angiogenesis; Animals; Antigens, CD - genetics; Capillaries - cytology; Capillaries - physiology; CD31/PECAM-1; Cell Adhesion; Cell Movement; Endothelial Cell; Endothelial Cells - cytology; Endothelial Cells - metabolism; Glycobiology; Glycobiology and Extracellular Matrices; Humans; Lung - blood supply; Mice; N-Acetylneuraminic Acid - metabolism; Neovascularization, Physiologic; Neuraminidase; Neuraminidase - metabolism; Platelet Endothelial Cell Adhesion Molecule-1 - metabolism; Protein Transport; Sialic Acid; Sialidase; Sialoproteins; Sialyltransferase; Sialyltransferases - genetics; Sialic Acid; Angiogenesis; CD31/PECAM-1; Glycobiology; Sialoproteins; Neuraminidase; Sialyltransferase; Endothelial Cell; Sialidase
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M114.555888

The highly sialylated vascular endothelial surface undergoes changes in sialylation upon adopting the migratory/angiogenic phenotype. We recently established endothelial cell (EC) expression of NEU1 sialidase (Cross, A. S., Hyun, S. W., Miranda-Ribera, A., Feng, C., Liu, A., Nguyen, C., Zhang, L., Luzina, I. G., Atamas, S. P., Twaddell, W. S., Guang, W., Lillehoj, E. P., Puché, A. C., Huang, W., Wang, L. X., Passaniti, A., and Goldblum, S. E. (2012) NEU1 and NEU3 sialidase activity expressed in human lung microvascular endothelia. NEU1 restrains endothelial cell migration whereas NEU3 does not. J. Biol. Chem. 287, 15966–15980). We asked whether NEU1 might regulate EC capillary-like tube formation on a Matrigel substrate. In human pulmonary microvascular ECs (HPMECs), prior silencing of NEU1 did not alter tube formation. Infection of HPMECs with increasing multiplicities of infection of an adenovirus encoding for catalytically active WT NEU1 dose-dependently impaired tube formation, whereas overexpression of either a catalytically dead NEU1 mutant, NEU1-G68V, or another human sialidase, NEU3, did not. NEU1 overexpression also diminished EC adhesion to the Matrigel substrate and restrained EC migration in a wounding assay. In HPMECs, the adhesion molecule, CD31, also known as platelet endothelial cell adhesion molecule-1, was sialylated via α2,6-linkages, as shown by Sambucus nigra agglutinin lectin blotting. NEU1 overexpression increased CD31 binding to Arachis hypogaea or peanut agglutinin lectin, indicating CD31 desialylation. In the postconfluent state, when CD31 ectodomains are homophilically engaged, NEU1 was recruited to and desialylated CD31. In postconfluent ECs, CD31 was desialylated compared with subconfluent cells, and prior NEU1 silencing completely protected against CD31 desialylation. Prior CD31 silencing and the use of CD31-null ECs each abrogated the NEU1 inhibitory effect on EC tube formation. Sialyltransferase 6 GAL-I overexpression increased α2,6-linked CD31 sialylation and dose-dependently counteracted NEU1-mediated inhibition of EC tube formation. These combined data indicate that catalytically active NEU1 inhibits in vitro angiogenesis through desialylation of its substrate, CD31.
Background: Endothelia express NEU1 sialidase and undergo changes in sialylation during angiogenesis.
Results: CD31 is a NEU1 substrate, and NEU1 disrupts endothelial cell capillary-like tube formation.
Conclusion: NEU1 works through its substrate, CD31, to dysregulate angiogenesis.
Significance: Human NEU1 is the first sialidase found to regulate angiogenesis, and the CD31 sialylation state dictates its ability to influence endothelial cell differentiation and tube formation.