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YBX1 Promotes the Inclusion of RUNX2 Alternative Exon 5 in Dental Pulp Stem Cells
International Journal of Stem Cells
Published online December 31, 2021;  
© 2021 Korean Society for Stem Cell Research.

Jiaoxiang Shen1,2,*, Wenting She1,3,*, Fengxia Zhang1, Jihua Guo1,4, Rong Jia1

1The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
2Department of Orthodontics, Stomatological Hospital of Xiamen Medical College, Xiamen, China
3Department of Stomatology, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China
4Department of Endodontics, School & Hospital of Stomatology, Wuhan University, Wuhan, China
Correspondence to: Jihua Guo
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079, China
Tel: +86-27-87686208, Fax: +86-27-87647443, E-mail: jihuaguo@whu.edu.cn
Rong Jia
The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079, China
Tel: +86-27-87686268, Fax: +86-27-87647443, E-mail: jiarong@whu.edu.cn
*These authors contriWbuted equally to this work.
Received February 21, 2021; Revised September 3, 2021; Accepted October 25, 2021.
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Background and Objectives: RUNX2 plays an essential role during the odontoblast differentiation of dental pulp stem cells (DPSCs). RUNX2 Exon 5 is an alternative exon and essential for RUNX2 transcriptional activity. This study aimed to investigate the regulatory mechanisms of RUNX2 exon 5 alternative splicing in human DPSCs.
Methods and Results: The regulatory motifs of RUNX2 exon 5 were analyzed using the online SpliceAid program. The alternative splicing of RUNX2 exon 5 in DPSCs during mineralization-induced differentiation was analyzed by RT-PCR. To explore the effect of splicing factor YBX1 on exon 5 alternative splicing, gaining or losing function of YBX1 was performed by transfection of YBX1 overexpression plasmid or anti-YBX1 siRNA in DPSCs. Human RUNX2 exon 5 is evolutionarily conserved and alternatively spliced in DPSCs. There are three potential YBX1 binding motifs in RUNX2 exon 5. The inclusion of RUNX2 exon 5 and YBX1 expression level increased significantly during mineralization- induced differentiation in DPSCs. Overexpression of YBX1 significantly increased the inclusion of RUNX2 exon 5 in DPSCs. In contrast, silence of YBX1 significantly reduced the inclusion of exon 5 and the corresponding RUNX2 protein expression level. Knockdown of YBX1 reduced the expression of alkaline phosphatase (ALP) and osteocalcin (OC) and the mineralization ability of DPSCs, while overexpression of YBX1 increased the expression of ALP and OC and the mineralization ability of DPSCs.
Conclusions: Human RUNX2 exon 5 is conserved evolutionarily and alternatively spliced in DPSCs. Splicing factor YBX1 promotes the inclusion of RUNX2 exon 5 and improves the mineralization ability of DPSCs.
Keywords : RUNX2, Exon 5, YBX1, Dental pulp stem cells