Quaking promotes the odontoblastic differentiation of human dental pulp stem cells

Abstract

Odontoblastic differentiation of human dental pulp stem cells (hDPSCs) is essential for the formation of reparative dentin after dental caries or injury. Our previous studies have demonstrated that krüppel-like factor 4 (KLF4) is a critical transcription factor that promotes the odontoblastic differentiation of hDPSCs. Analysis of the microRNA binding sites within the 3'-UTR of KLF4 revealed that QKI, an RNA-binding protein, shared the most microRNAs with KLF4, presumably served as a "competent endogenous RNA (ceRNA)" with KLF4. Thus, we hypothesized QKI could also promote odontoblastic differentiation. In this study, we found QKI was up-regulated during mouse odontoblast differentiation in vivo and hDPSCs odontoblastic differentiation in vitro. Overexpression or knockdown of QKI in hDPSCs led to the increase or decrease of odontoblast marker genes' expressions, indicating its positive role in odontoblastic differentiation. We further validated that QKI served as a key ceRNA of KLF4 via interaction of the shared miRNAs in hDPSCs. Last, we found that, as an RNA binding protein, QKI protein could bind to, and stabilize dentin sialophosphoprotein (DSPP) mRNA, resulting in the augmented accumulation of DSP protein. Taken together, our study indicates that QKI promotes the odontoblastic differentiation of hDPSCs by acting as a ceRNA of KLF4 and as a binding protein of DSPP mRNA to stabilize its level. These two mechanisms of QKI will together positively regulate the downstream pathways and hence potentiate odontoblastic differentiation.

Klf4 Promotes Dentinogenesis and Odontoblastic Differentiation via Modulation of TGF-β Signaling Pathway and Interaction With Histone Acetylation

“…We also performed several in vitro experiments and verified that KLF4 is an important transcription factor that promotes the odontoblast differentiation of mouse dental pulp cells and mDPCs . Furthermore, in vitro experiments revealed that, during odontoblast differentiation, klf4 is posttranscriptionally regulated by mir‐143 and mir‐145, and Sp1 and Qki were also found to act as competent endogenous RNAs (ceRNAs) of KLF4 to promote odontoblast differentiation in vitro . However, the in vivo role of KLF4 in the commitment of dentin progenitors or dentinogenesis has not been extensively described.…”

“…(19,20) Furthermore, in vitro experiments revealed that, during odontoblast differentiation, klf4 is posttranscriptionally regulated by mir-143 and mir-145, (21,22) and Sp1 and Qki were also found to act as competent endogenous RNAs (ceRNAs) of KLF4 to promote odontoblast differentiation in vitro. (23,24) However, the in vivo role of KLF4 in the commitment of dentin progenitors or dentinogenesis has not been extensively described.…”

SP1 regulates KLF4 via SP1 binding motif governed by DNA methylation during odontoblastic differentiation of human dental pulp cells

“…Flow cytometry assay was used to further characterize the hDPCs. The experiment were performed according to the protocol described before . Results showed that mesenchymal stem cell markers like CD44 (FITC, BioLegend, San Diego, CA) and CD90 (FITC, BioLegend) were dominantly positive in hDPCs population while CD34 (FITC, BioLegend) and CD45 (FITC, BioLegend), which are hematopoietic markers, showed negative signals (Supplemental Figure S1 B‐E).…”

Gelatinases Cleave Dentin Sialoprotein Intracellularly

“…Because real native odontoblasts display long cell processes embedded into the dentinal tubules, the isolation of real odontoblasts will lead to damage and cell death. Therefore, induction of dental papilla cells into odontoblastic cells in vitro has been widely used as an excellent model for odontoblast-related experiments in many reports ( Chen et al, 2015 ; Yang et al, 2015 ; Zhang et al, 2015 ; Iwamoto et al, 2017 ; Li Q. et al, 2018 ; Li s. et al, 2018 ; Zheng et al, 2020 ). In this study, we confirmed these cells as odontoblastic cells as described previously ( Zheng et al, 2020 ).…”