Laboratory of Oral Connective Tissue Biology, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA.
Division of Periodontology, School of Dentistry, University of Maryland, Baltimore, MD, USA.
J Dent Res. 2021 Aug;100(9):993-1001. doi: 10.1177/00220345211005677. Epub 2021 Apr 10.
Factors regulating the ratio of pyrophosphate (PP) to phosphate (P) modulate biomineralization. Tissue-nonspecific alkaline phosphatase (TNAP) is a key promineralization enzyme that hydrolyzes the potent mineralization inhibitor PP. The goal of this study was to determine whether TNAP could promote periodontal regeneration in bone sialoprotein knockout mice ( mice), which are known to have a periodontal disease phenotype. Delivery of TNAP was accomplished either systemically (through a lentiviral construct expressing a mineral-targeted TNAP-D protein) or locally (through addition of recombinant human TNAP to a fenestration defect model). Systemic TNAP-D delivered by intramuscular injection at 5 d postnatal (dpn) increased circulating alkaline phosphatase (ALP) levels in mice by 5-fold at 30 dpn, with levels returning to normal by 60 dpn when tissues were evaluated by micro-computed tomography and histology. Local delivery of recombinant human TNAP to fenestration defects in 5-wk-old wild type (WT) and mice did not alter long-term circulating ALP levels, and tissues were evaluated by micro-computed tomography and histology at postoperative day 45. Systemic and local delivery of TNAP significantly increased alveolar bone volume (20% and 37%, respectively) and cementum thickness (3- and 42-fold) in mice, with evidence for periodontal ligament attachment and bone/cementum marker localization. Local delivery significantly increased regenerated cementum and bone in WT mice. Addition of 100-μg/mL bovine intestinal ALP to culture media to increase ALP in vitro increased media P concentration, mineralization, and and marker gene expression in WT and OCCM.30 cementoblasts. Use of phosphonoformic acid, a nonspecific inhibitor of sodium P cotransport, indicated that effects of bovine intestinal ALP on mineralization and marker gene expression were in part through P transport. These findings show for the first time through multiple in vivo and in vitro approaches that pharmacologic modulation of P/PP metabolism can overcome periodontal breakdown and accomplish regeneration.
调节焦磷酸盐（PP）与磷酸盐（P）比例的因素可调节生物矿化。组织非特异性碱性磷酸酶（TNAP）是一种关键的促矿化酶，可水解强力的矿化抑制剂 PP。本研究的目的是确定 TNAP 是否可促进骨唾液蛋白敲除小鼠（ 小鼠）的牙周再生，已知这些小鼠具有牙周病表型。TNAP 的递呈可通过系统途径（通过表达矿化靶向 TNAP-D 蛋白的慢病毒构建体）或局部途径（将重组人 TNAP 添加到窗孔缺陷模型中）来实现。通过肌肉内注射在出生后 5 天（dpn）给予系统递送的 TNAP-D，可使 小鼠的循环碱性磷酸酶（ALP）水平在 30 dpn 时增加 5 倍，而在 60 dpn 时当通过微计算机断层扫描和组织学评估组织时，水平恢复正常。将重组人 TNAP 局部递送至 5 周龄野生型（WT）和 小鼠的窗孔缺陷中，不会改变长期循环 ALP 水平，并且在术后第 45 天通过微计算机断层扫描和组织学评估组织。TNAP 的系统和局部递呈可使 小鼠的牙槽骨体积（分别增加 20%和 37%）和牙骨质厚度（增加 3-和 42 倍）显著增加，有牙周韧带附着和骨/牙骨质标记物定位的证据。局部递呈可显著增加 WT 小鼠再生的牙骨质和骨。将 100-μg/mL 牛肠碱性磷酸酶添加到培养基中以增加体外 ALP 水平，增加了培养基 P 浓度、矿化和 WT 和 小鼠的 OCCM.30 成牙骨质细胞的 和 标记基因表达。使用膦甲酸，一种钠 P 共转运的非特异性抑制剂，表明牛肠碱性磷酸酶对矿化和标记基因表达的影响部分是通过 P 转运。这些发现首次通过多种体内和体外方法表明，通过药理学调节 P/PP 代谢可以克服牙周破坏并实现再生。
