Felthaus Oliver, Gosau Martin, Morsczeck Christian
Department of Cranio- and Maxillofacial Surgery, University Hospital Regensburg, Regensburg, Germany.
J Periodontol. 2014 May;85(5):e144-51. doi: 10.1902/jop.2013.130445. Epub 2013 Dec 22.
Dental follicle cells (DFCs) are neural crest cell-derived cells and the genuine precursor cells of cementoblast and alveolar osteoblasts. After osteogenic differentiation, expression levels of the transcription factor zinc factor and BTB domain containing 16 (ZBTB16) were significantly increased. ZBTB16 is associated with the process of osteogenic differentiation in bone marrow-derived mesenchymal stem cells and crucial for the expression of the osteogenic transcription factor runt-related transcription factor 2 (RUNX2). It is proposed that ZBTB16 plays also a crucial role for the differentiation of DFCs into osteoblasts.
In this study, the differentiation of DFCs by alkaline phosphatase (ALP) activity measurement, alizarin red staining, and electron-dispersive x-ray spectrometry (EDX) analysis is investigated. The expression of ZBTB16 during osteogenic differentiation and the expression of osteogenic differentiation markers were assessed by real-time reverse transcription polymerase chain reaction. Glucocorticoid stimulation was inhibited using RU486 (11β-[p-(Dimethylamino)phenyl]-17β-hydroxy-17-(1-propynyl)estra-4,9-dien-3-one), and ZBTB16 was overexpressed via transient transfection of an expression vector.
After the initiation of osteogenic differentiation, ZBTB16 levels were increased highly in DFCs, whereas RUNX2 was expressed constitutively only. An EDX analysis verified the differentiation of DFCs into osteoblast-like cells because clusters of mineralization consisted of hydroxyapatite. ZBTB16 induced the expression of nuclear receptor subfamily 4, group A, member 3; osteocalcin; and stanniocalcin 1 (STC1) but not of RUNX2 and ALP in DFCs. STC1 was upregulated in DFCs downstream of ZBTB16 and after the osteogenic differentiation. The overexpression of STC1 in DFCs increased the expression of ZBTB16 and specific markers for biomineralization.
The present study shows that ZBTB16 induced the expression of osteogenic differentiation markers independently of RUNX2. Moreover, STC1 is a new candidate for the evaluation of late mechanisms of osteogenic differentiation downstream of ZBTB16.
牙囊细胞（DFCs）是神经嵴细胞来源的细胞，是成牙骨质细胞和牙槽成骨细胞的真正前体细胞。在成骨分化后，转录因子锌指和含BTB结构域16（ZBTB16）的表达水平显著升高。ZBTB16与骨髓间充质干细胞的成骨分化过程相关，对成骨转录因子 runt相关转录因子2（RUNX2）的表达至关重要。有人提出ZBTB16对DFCs向成骨细胞的分化也起着关键作用。
在本研究中，通过碱性磷酸酶（ALP）活性测定、茜素红染色和能量色散X射线光谱（EDX）分析研究DFCs的分化。通过实时逆转录聚合酶链反应评估成骨分化过程中ZBTB16的表达和成骨分化标志物的表达。使用RU486（11β-[对-（二甲基氨基）苯基]-17β-羟基-17-（1-丙炔基）雌甾-4,9-二烯-3-酮）抑制糖皮质激素刺激，并通过瞬时转染表达载体使ZBTB16过表达。
成骨分化开始后，DFCs中ZBTB16水平高度升高，而RUNX2仅持续表达。EDX分析证实DFCs分化为成骨样细胞，因为矿化簇由羟基磷灰石组成。ZBTB16诱导DFCs中核受体亚家族4 A组成员3、骨钙素和骨抑素1（STC1）的表达，但不诱导RUNX2和ALP的表达。STC1在ZBTB16下游和DFCs成骨分化后上调。DFCs中STC1的过表达增加了ZBTB16和生物矿化特异性标志物的表达。
本研究表明ZBTB16独立于RUNX2诱导成骨分化标志物的表达。此外，STC1是评估ZBTB16下游成骨分化晚期机制的新候选物。
