A novel mutation of SATB2 inhibits odontogenesis of human dental pulp stem cells through Wnt/\u03b2-catenin signaling pathway

Tianyi Xin,Ting Zhang,Ruili Yang,Yuehua Zhang,Yuehua Zhang,Bing Han,Yanheng Zhou,Rushui Bai,Qian Li

doi:10.1186/s13287-021-02660-8

Tianyi Xin, Ting Zhang + Show 7 more

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https://doi.org/10.1186/s13287-021-02660-8

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Abstract

BackgroundSATB2-associated syndrome (SAS) is a multisystem disorder caused by mutation of human SATB2 gene. Tooth agenesis is one of the most common phenotypes observed in SAS. Our study aimed at identifying novel variant of SATB2 in a patient with SAS, and to investigate the cellular and molecular mechanism of tooth agenesis caused by SATB2 mutation.MethodsWe applied whole exome sequencing (WES) to identify the novel mutation of SATB2 in a Chinese patient with SAS. Construction and overexpression of wild-type and the mutant vector was performed, followed by functional analysis including flow cytometry assay, fluorescent immunocytochemistry, western blot, quantitative real-time PCR and Alizarin Red S staining to investigate its impact on hDPSCs and the underlying mechanisms.ResultsAs a result, we identified a novel frameshift mutation of SATB2 (c. 376_378delinsTT) in a patient with SAS exhibiting tooth agenesis. Human DPSCs transfected with mutant SATB2 showed decreased cell proliferation and odontogenic differentiation capacity compared with hDPSCs transfected with wild-type SATB2 plasmid. Mechanistically, mutant SATB2 failed to translocate into nucleus and distributed in the cytoplasm, failing to activate Wnt/β-catenin signaling pathway, whereas the wild-type SATB2 translocated into the nucleus and upregulated the expression of active β-catenin. When we used Wnt inhibitor XAV939 to treat hDPSCs transfected with wild-type SATB2 plasmid, the increased odontogenic differentiation capacity was attenuated. Furthermore, we found that SATB2 mutation resulted in the upregulation of DKK1 and histone demethylase JHDM1D to inhibit Wnt/β-catenin signaling pathway.ConclusionWe identified a novel frameshift mutation of SATB2 (c.376_378delinsTT, p.Leu126SerfsX6) in a Chinese patient with SATB2-associated syndrome (SAS) exhibiting tooth agenesis. Mechanistically, SATB2 regulated osteo/odontogenesis of human dental pulp stem cells through Wnt/β-catenin signaling pathway by regulating DKK1 and histone demethylase JHDM1D.

Highlights

Special AT-rich sequence binding protein 2 (SATB2)-associated syndrome (SAS) is a multisystem disorder caused by mutation of human SATB2 gene
We conducted live/dead viability assay after transfection, and the results demonstrated that both wild-type and mutant SATB2 decreased cell viability compared with control, but no significant difference was found between wild-type and mutant groups (Additional file 1: Fig. S1)
We transfected wild-type and mutant SATB2 to Human dental pulp stem cells (hDPSCs) and the results showed that hDPSCs transfected with mutant SATB2 showed a decreased calcium nodule formation ability compared with wild-type ones (Fig. 3d)

Summary

Introduction

SATB2-associated syndrome (SAS) is a multisystem disorder caused by mutation of human SATB2 gene. SATB2-associated syndrome (SAS) is a recently named multisystem disorder manifesting as developmental delay with limited speech, craniofacial abnormalities including dental anomalies and cleft palate, facial dysmorphism and behavioral problems [1, 2]. Loss of Satb results in cleft palate, shorter lower jaw and missing of incisor teeth [5]. These manifestations are consistent with the phenotype in human with SATB2 mutation [3, 7,8,9]. The mechanism of how SATB2 mutation results in tooth agenesis in human is rarely studied

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