title: Dental Follicle Cells Participate in Tooth Eruption via the RUNX2-MiR-31-SATB2 Loop.
abstract: Cleidocranial dysplasia (CCD) is characterized by the runt-related transcription factor 2 (RUNX2) mutation, which results in delayed tooth eruption due to disturbed functions of dental follicle. Accumulating evidence has revealed a key regulatory circuit, including RUNX2, miR-31, and special AT-rich binding protein 2 (SATB2) acting in concert in mesenchymal stem cell homeostasis and functions. However, whether such a regulatory loop works in dental follicle cells (DFCs) remains unknown. Herein, we investigated the roles of RUNX2-miR-31-SATB2 in DFCs from patients with CCD (DFCs-CCD) to advance our understanding regarding physical tooth eruption. We identified a novel mutation on exon 5 (c.634T>G, p.T212P) in RUNX2 via exome sequencing in the CCD patient with typical clinical presentations. Compared with DFCs from healthy donors, DFCs-CCD displayed significantly lower osteogenic, osteoclast-inductive, and matrix-degrading capacities and had lower RUNX2 (a transcriptional inhibitor of miR-31), higher miR-31, and downregulated SATB2. Lower ratios of RANKL/OPG and RANKL/RANK, as well as decreased expression of matrix metalloproteinase 9 (MMP9) and matrix metalloproteinase 2 (MMP2), would lead to inactivation of osteoclasts and suppression of bone matrix remodeling in DFCs-CCD. Furthermore, the roles of the RUNX2-miR-31-SATB2 loop in DFCs-CCD were revealed by endogenous miR-31 knockdown, which resulted in increased SATB2 and RUNX2, as well as osteoclast-inductive and matrix degradation capacities. Conversely, SATB2, RUNX2, MMP9, MMP2, and osteoclast-inductive factors expression declined upon ectopic miR-31 overexpression in normal DFCs. Importantly, neonatal mice with in vivo siRUNX2 delivery exhibited less activated osteoclasts around dental follicles and delayed tooth eruption. Together, these results suggest that RUNX2 mutation/haploinsufficiency disturbs osteoclast-inductive signaling in DFCs, which may be responsible for delayed tooth eruption in CCD patients. Manipulation of the RUNX2-miR-31-SATB2 loop may be a potential way to facilitate tooth eruption in CCD patients.
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: J
authors.initials: J
authors.lastname: Ge
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: S
authors.initials: S
authors.lastname: Guo
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Fu
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China.
authors.forename: P
authors.initials: P
authors.lastname: Zhou
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China.
authors.forename: P
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Du
authors.affiliation: Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China.
authors.forename: M
authors.initials: M
authors.lastname: Li
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China.
authors.forename: J
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Jiangsu Key Laboratory of Oral Diseases, Nanjing Medical University, Nanjing, China Department of Oral and Maxillofacial Surgery, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, China jhb@njmu.edu.cn leonardo_cheng@163.com.
authors.forename: H
authors.initials: H
authors.lastname: Jiang
mesh_terms: D000293:Adolescent; D000818:Animals; D000831:Animals, Newborn; D016723:Bone Remodeling / Q000502:physiology; D002478:Cells, Cultured; D002648:Child; D002973:Cleidocranial Dysplasia / Q000235:genetics; D018920:Coculture Techniques; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000502:physiology*; D003795:Dental Sac / Q000473:pathology*; D005091:Exons / Q000235:genetics; D055785:Gene Knockdown Techniques; D006147:Guanine; D057895:Haploinsufficiency / Q000235:genetics; D006801:Humans; D008297:Male; D036961:Matrix Attachment Region Binding Proteins / Q000502:physiology*; D020778:Matrix Metalloproteinase 2 / Q000032:analysis; D020780:Matrix Metalloproteinase 9 / Q000032:analysis; D051379:Mice; D008810:Mice, Inbred C57BL; D035683:MicroRNAs / Q000502:physiology*; D009154:Mutation / Q000235:genetics; D010010:Osteoclasts / Q000502:physiology; D010012:Osteogenesis / Q000235:genetics; D053244:Osteoprotegerin / Q000032:analysis; D053245:RANK Ligand / Q000032:analysis; D053246:Receptor Activator of Nuclear Factor-kappa B / Q000032:analysis; D013941:Thymine; D014078:Tooth Eruption / Q000502:physiology*; D014157:Transcription Factors / Q000502:physiology*
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; C534612:MIRN31 microRNA, human; D036961:Matrix Attachment Region Binding Proteins; D035683:MicroRNAs; D053244:Osteoprotegerin; D053245:RANK Ligand; C493709:RUNX2 protein, human; D053246:Receptor Activator of Nuclear Factor-kappa B; C521297:SATB2 protein, human; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D014157:Transcription Factors; D006147:Guanine; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; D013941:Thymine
keywords: bone remodeling; cleidocranial dysplasia; dental sac; matrix metalloproteinases; microRNA; osteoclasts