title: Human airway epithelia express catalytically active NEU3 sialidase.
abstract: Sialic acids on glycoconjugates play a pivotal role in many biological processes. In the airways, sialylated glycoproteins and glycolipids are strategically positioned on the plasma membranes of epithelia to regulate receptor-ligand, cell-cell, and host-pathogen interactions at the molecular level. We now demonstrate, for the first time, sialidase activity for ganglioside substrates in human airway epithelia. Of the four known mammalian sialidases, NEU3 has a substrate preference for gangliosides and is expressed at mRNA and protein levels at comparable abundance in epithelia derived from human trachea, bronchi, small airways, and alveoli. In small airway and alveolar epithelia, NEU3 protein was immunolocalized to the plasma membrane, cytosolic, and nuclear subcellular fractions. Small interfering RNA-induced silencing of NEU3 expression diminished sialidase activity for a ganglioside substrate by >70%. NEU3 immunostaining of intact human lung tissue could be localized to the superficial epithelia, including the ciliated brush border, as well as to nuclei. However, NEU3 was reduced in subepithelial tissues. These results indicate that human airway epithelia express catalytically active NEU3 sialidase.
authors.affiliation: Ph.D., Dept. of Pediatrics, Univ. of Maryland School of Medicine, 655 W. Baltimore St., Rm. 13-029, Baltimore, Maryland 21201. elillehoj@peds.umaryland.edu.
authors.forename: Erik P
authors.initials: EP
authors.lastname: Lillehoj
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Hyun
authors.forename: Chiguang
authors.initials: C
authors.lastname: Feng
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Anguo
authors.initials: A
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Guang
authors.forename: Chinh
authors.initials: C
authors.lastname: Nguyen
authors.forename: Wenji
authors.initials: W
authors.lastname: Sun
authors.forename: Irina G
authors.initials: IG
authors.lastname: Luzina
authors.forename: Tonya J
authors.initials: TJ
authors.lastname: Webb
authors.forename: Sergei P
authors.initials: SP
authors.lastname: Atamas
authors.forename: Antonino
authors.initials: A
authors.lastname: Passaniti
authors.forename: William S
authors.initials: WS
authors.lastname: Twaddell
authors.forename: Adam C
authors.initials: AC
authors.lastname: Puché
authors.forename: Lai-Xi
authors.initials: LX
authors.lastname: Wang
authors.forename: Alan S
authors.initials: AS
authors.lastname: Cross
authors.forename: Simeon E
authors.initials: SE
authors.lastname: Goldblum
mesh_terms: D019921:Biotinylation; D015153:Blotting, Western; D002384:Catalysis; D002462:Cell Membrane / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism*; D005434:Flow Cytometry; D005732:Gangliosides / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D009439:Neuraminidase / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012137:Respiratory System / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012794:Sialic Acids / Q000378:metabolism; D013347:Subcellular Fractions
chemical_list: D005732:Gangliosides; D012333:RNA, Messenger; D012794:Sialic Acids; C486385:NEU1 protein, human; C465436:Neu3 protein, human; D009439:Neuraminidase
keywords: epithelial cell; ganglioside; lung; neuraminidase; sialic acid