Epithelial Wnt10a Is Essential for Tooth Root Furcation Morphogenesis

Abstract

WNT10A (Wingless-type MMTV integration site family, member 10A) plays a crucial role in tooth development, and patients with biallelic WNT10A mutation and mice lacking Wnt10a show taurodontism. However, whether epithelial or mesenchymal WNT10A controls the initiation of the root furcation formation remains unclear, and the functional significance of WNT10A in regulating root morphogenesis has not been clarified. Here, we investigated how Wnt10a affects tooth root development by generating different tissue-specific Wnt10a conditional knockout mice. Wnt10a knockout in the whole tissue ( EIIa-Cre;Wnt10aflox/flox) and in dental epithelium ( K14-Cre;Wnt10aflox/flox) led to an absence of or apically located root furcation in molars of mice, a phenotype that resembled taurodontism. An RNAscope analysis showed that the dynamic epithelial and mesenchymal Wnt10a expression pattern occurred during root development. Immunofluorescent staining of E-cadherin and EdU revealed decreased epithelial cell proliferation at the cervical region of the molar in K14-Cre;Wnt10aflox/flox mice at postnatal day 0 (PN0), just before the initiation of root morphogenesis. Interestingly, we found increased pulpal mesenchymal cell proliferation in the presumptive root furcating region of the molar in K14-Cre;Wnt10aflox/flox mice at PN4 and PN7. RNA-seq indicated that among the Wnt ligands with high endogenous expression levels in molars, Wnt4 was increased after epithelial knockout of Wnt10a. The RNAscope assay confirmed that the expression of Wnt4 and Axin2 in the dental papilla of the presumptive root furcating region, where dental pulp overgrowth occurred, was increased in K14-Cre;Wnt10aflox/flox molars. Furthermore, after suppression of the elevated Wnt4 level in K14-Cre;Wnt10aflox/flox molars by Wnt4 shRNA adenovirus and kidney capsule grafts, the root furcation defect was partially rescued. Taken together, our study provides the first in vivo evidence that epithelial Wnt10a guides root furcation formation and plays a crucial role in controlling the organized proliferation of adjacent mesenchymal cells by regulating proper Wnt4 expression during root furcation morphogenesis.

Using WGCNA (weighted gene co-expression network analysis) to identify the hub genes of skin hair follicle development in fetus stage of Inner Mongolia cashmere goat

“…WNT10A is an important gene in ectodermal development, and its mutation may result in ectodermal dysplasia [ 41 ], with the main symptoms of abnormal development of dentin and nails and the appearance of cysts and erythema along the edge of the eyelid [ 53 , 54 ]. During tooth development, the specific expression of WNT10A in epithelial cells can induce tooth-root bifurcation, and it is therefore also considered as a key gene in the process of tooth differentiation, WNT10A also controls the proliferation of adjacent mesenchymal cells by regulating the expression of Wnt4 in mice [ 55 , 56 ].…”

“…All operating personnel were qualified veterinarians with at least 3 years of clinical experience. We collected samples of fetal skin from three fetuses for each period (45,55,65,75,95,115, and 135 days). The embryos were cleaned with diethyl pyrocarbonate water after cesarean section, and skin samples (1 cm 2 ) were collected quickly from the fetuses using sterile, enzyme-free disposable scalpels and forceps.…”

Tooth agenesis: What do we know and is there a connection to cancer?

“…In the cell differentiation phase, Wnt10a was expressed in preameloblasts, ameloblasts, and mesenchyme of dental papilla and odontoblasts. Wnt10b and Wnt10a expression overlap with the WNT co‐receptor LRP6 (low‐density lipoprotein receptor‐related protein 6), which highlights the involvement of the WNT signaling pathway in odontogenesis 54,56‐58 …”

A single cell atlas of human teeth

“…The most abundant periodontal cell type is represented by epithelial-like cells. These periodontal epithelial-like cells expressed genes encoding for signaling molecules such as FDCSP (Follicular Dendritic Cells Secreted Protein) and WNT10A, which exert fundamental roles in the modulation of periodontal MSCs proliferation and differentiation (Wei et al, 2011;Xu et al, 2017;Yu et al, 2020). Epithelial cells from the periodontium have been long proposed to constitute a dental epithelial stem cells population, with potential to generate toothassociated hard tissues such as enamel, dentin and alveolar bone (Athanassiou-Papaefthymiou et al, 2015;Tsunematsu et al, 2016).…”