Bmp signalling in filiform tongue papillae development

Abstract

Objective Tongue papillae are critical organs in mastication. There are four different types of tongue papillae; fungiform, circumvallate, foliate, and filiform papillae. Unlike the other three taste papillae, non-gustatory papillae, filiform papillae cover the entire dorsal surface of the tongue and are important structures for the mechanical stress of sucking. Filiform papillae are further classified into two subtypes with different morphologies, depending on their location on the dorsum of the tongue. The filiform papillae at the intermolar eminence have pointed tips, whereas filiform papillae with rounded tips are found in other regions (anterior tongue). It remains unknown how the shape of each type of filiform papillae are determined during their development. Bmp signalling pathway has been known to regulate mechanisms that determine the shapes of many ectodermal organs. The aim of this study was to investigate the role of Bmp signalling in filiform papillae development. Design Comparative in situ hybridization analysis of six Bmps (Bmp2–Bmp7) and two Bmpr genes (Bmpr1a and Bmpr1b) were carried out in filiform papillae development. We further examined tongue papillae in mice over-expressing Noggin under the keratin14 promoter (K14-Noggin). Results We identified a dynamic temporo-spatial expression of Bmps in filiform papillae development. The K14-Noggin mice showed pointed filiform papillae in regions of the tongue normally occupied by the rounded type. Conclusions Bmp signalling thus regulates the shape of filiform papillae.

Serum starvation-induces down-regulation of Bcl-2/Bax confers apoptosis in tongue coating-related cells in�vitro

“…These features have been examined via electron microscopy studies, with the formation of the tongue coating found to be dependent on the physiological state of filiform papillae ( 4 ). For example, the filiform papillae within the cuticle of a thick coating are prominent and dense, while the cuticle of a thin coating is obviously atrophied ( 5 ). The epidermis of the tongue dorsum contains a highly specialized epithelium consisting of several stratified cell layers called squamous epithelium, with these epithelial cells continuously renewed by the mitotic activity of stem cells within the basal layer ( 6 ).…”

RNA-Seq analysis on chicken taste sensory organs: An ideal system to study organogenesis

“…8C ), Wnt/β-catenin 38 , 40 , 50 – 52 (Fig. 8D ), TGF-β/BMP 36 , 46 , 53 , 54 (Fig. 8E ), Notch 55 – 57 (Fig.…”

Regional regulation of Filiform tongue papillae development by Ikkα/Irf6

“…Non‐gustatory filiform papillae are important for helping to grip food, drawing food to the esophagus, cleaning the mouth, and spreading saliva. Although filiform papillae cover the entire dorsal surface of the tongue, it has been shown that there are morphological differences between the filiform papillae in the intermolar eminence and those in anterior region, which are regulated by Bmp signaling (Beites et al, ; Kawasaki et al, ). In addition to the differences between the anterior tongue and the intermolar eminence, our results suggest that there is another distinct developmental mechanism for the mesio‐lateral axis of the dorsum tongue, which is regulated by Ikkα and Irf6 .…”