A novel type of cells expressing GP2 in the respiratory epithelium of the paranasal sinuses in mice

Abstract

GP2, a GPI-anchored glycoprotein, is a useful marker of M cells in Peyer's patches. Our immunostaining of the paranasal sinuses in mice detected a condensed distribution of GP2-immunoreactive cells within the epithelium, apart from lymphoid tissues. In the paranasal sinuses, the cells exhibited a unique morphology characterized by a slender neck portion and huge terminal bulb, quite different from M cells. Electron microscopically, the GP2 immunoreactivity centered on the luminal plasma membrane of the terminal bulb, being less intense in the baso-lateral plasma membrane and not visible at all in the cytoplasm. The cells frequently came in contact with nerve fibers containing small synaptic vesicles. These nerve fibers contained neither CGRP nor substance P-indicators of sensory neurons; moreover, no signal molecules used for a sensory function were expressed in the GP2-immunoreactive cells, implying that these nerves are efferent in nature. A weak but significant stainability in PAS reaction and an intense GP2 immunoreactivity for typical goblet cells in the tunica conjunctiva suggest that the GP2-expressing cells in paranasal sinuses are in the lineage of goblet cells.

RANKL regulates differentiation of microfold cells in mouse nasopharynx-associated lymphoid tissue (NALT)

“…This protein is also a well$known functional marker of intestinal M cells; GP2 appears in the later stage of M-cell differentiation, and its expression has been correlated with the uptake capacity of luminal microbeads (Hase et al 2009a;Kimura et al 2015). In the head region of mice, numerous GP2-expressing non-ciliated cells were found to be distributed in the epithelium covering the paranasal sinuses, tear ducts, and conjunctiva (Kimura et al 2014; our unpublished data).…”

“…Histochemical studies suggested that GP2-expressing cells in the paranasal sinuses and conjunctiva were a lineage of goblet cells because they were more or less positive for Periodic Acid Schiff (PAS) staining (Kimura et al 2014 …”

“…2c and d) (Clark et al 1993). However, the specificity of UEA-I histochemistry was low because this method labeled not only a population of M cells but also other epithelial cells in the nasal cavity (Kimura et al 2014). These molecular and morphological features indicated that GP2 + Tnfaip2 + cells in the nasal cavity were typical M cells.…”

Gene and metabolite time-course response to cigarette smoking in mouse lung and plasma

“…Two of the persistently altered genes, Lox and Gp2 , have not been previously implicated in mouse models of active chronic CS exposure. The persistent upregulation of Gp2 , a gene expressed in goblet cells [33] may link it to the heightened mucosal immune response induced by CS exposure [17]. Lox , the only significantly bi-directionally persistently altered gene encodes the precursor protein lysyl oxidase, required to crosslink collagen and elastin, which makes it critical to vascular and extracellular matrix remodeling.…”

<b>The broad distribution of GP2 in mucous glands and secretory pr</b><b>oducts </b>

“…Although GP2 is one of the main secretory products of the pancreas, other secretory cells, such as conjunctival goblet cells, have an ability to produce GP2 (12). Epithelial cells dispersed in the respiratory epithelium of the paranasal sinuses were weakly positive for periodic acid-Schiff (PAS) reaction but intensely immunolabeled with the GP2 antibody (11). Furthermore, epithelial cells distributed in the lacrimal canaliculi, lacrimal sac, and nasolacrimal duct contained GP2 along the basolateral membrane and showed a sign of the release of GP2 into the lumen (12).…”