Sialoglycoproteins and penultimate sugar expression pattern in developing murine olfactory and respiratory mucosa

Abstract

Sialic acid residues are constant constituents of the glycoproteins of the airways in all species. Sialoglycoproteins are the main acidic glycoprotein and their functions are to mediate cell adherence, to control the viscoelasticity of mucus and to serve as receptor sites for the binding of exogenous macromolecules. The purpose of this study was to investigate the differences in the distribution of sialoglycoproteins as a terminal sugar and in the composition of the penultimate sugar according to aging in the murine nasal respiratory and olfactory mucosa. Nasal cavities of mice (BALB/c) were fixed by intracardiac perfusion with 2.0% glutaraldehyde and embedded in Epon 812. First, the serial sections were stained with Maackia amurensis agglutinin (MAA) and Sambucus nigra agglutinin (SNA). Then, the adjacent sections were stained with DBA and PNA before and after neuraminidase digestion in all experimental groups. Apical cell surfaces of olfactory mucosa and cilia on a few ciliated cells in the mucosa of the septum and nasal floor were labelled with MAA, but cell surfaces of respiratory mucosa, Bowman's glands and goblet cells were not labelled with MAA, irrespective of aging. Apical cell surfaces of both olfactory and respiratory mucosa and Bowman's glands were stained with SNA, however, goblet cells were not labelled with SNA. After neuraminidase digestion to remove terminal sialic acid residues of sialoglycoproteins, only cell surfaces of respiratory mucosa were labelled with PNA, but goblet cells, cell surfaces of olfactory mucosa and Bowman's glands were not labelled with PNA. Cell surfaces and Bowman's glands of olfactory mucosa were labelled with DBA after neuraminidase digestion, but cell surfaces of respiratory mucosa and goblet cells were not labelled with DBA. Our results indicate that there were different carbohydrate structures of sialoglycoconjugates in olfactory and respiratory mucosa, and it was not influenced by aging.

Detection of Parainfluenza Virus 3 in Turbinate Epithelial Cells of Postviral Olfactory Dysfunction Patients

“…PIV3 initiates infection by binding to α2 to 6‐linked sialic acid‐containing cell surface receptors and replicates in the ciliated cells of human airway epithelium 8,21 . In the olfactory and respiratory mucosa of the mouse, sialic acid residues with α2 to 6‐linkage were detected using SNA lectin, which is specific to α2 to 6‐linked sialic acid residues 22 . In addition, PIV3 has been isolated from the cerebrospinal fluid of aseptic meningitis patients, suggesting the neurotropism of PIV3 and further supporting the idea that the virus may infect the olfactory epithelium 23 …”

Long-term persistence of gene expression from adeno-associated virus serotype 5 in the mouse airways

“…18,19 However, the distribution of 2,3-N-linked sialic acid in murine nasal epithelium as determined by lectin-binding assays is controversial. Studies by Foster et al 48 and Yoon et al 49 both suggested that the murine nasal respiratory epithelium was not labelled with Maackia amurensis agglutinin (MAA), which normally binds 2,3-N-linked sialic acid, while Ueno et al 50 detected MAA binding on all nasal surfaces. So it remains feasible that a relative paucity of AAV5 receptor is responsible for the lack of EGFP-positive cells in the nasal respiratory epithelial cells.…”

Muc5b is mainly expressed and sialylated in the nasal olfactory epithelium whereas Muc5ac is exclusively expressed and fucosylated in the nasal respiratory epithelium

“…In the horse, the UEA-1 fucose lectin was found to label BGs in the OE (Lee et al 2016). In the nose of mice, sialomucin with different terminal carbohydrate structures has been observed in the RE and OE, which may reflect differences in the susceptibility to bacterial colonization between the two epithelia (Ueno et al 1994;Yoon et al 1998). These two last studies reported that the mouse OE, but not the goblet cells of the RE is sialylated, whereas one study showed that mouse BGs produced sulfated but not sialylated glycoconjugates using high-iron diamine-AB staining (Kondo et al 2009).…”