Deletion or mutation of dentin matrix protein 1 (DMP1) leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirec...Deletion or mutation of dentin matrix protein 1 (DMP1) leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate (Pi) or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmp1-null (Dmp1 2/2 ), Klotho-deficient (kl/kl), Dmp1/Klotho-double-deficient (Dmp1 2/2 /kl/kl) and wild-type (WT) mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography (mCT), scanning electron microscopy (SEM), histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmp1 2/2 (a low Pi level) or kl/kl (a high Pi level) mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice (a high Pi level) displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment (a high Pi level).展开更多
Dentin matrix protein 1(DMP1) is essential to odontogenesis. Its mutations in human subjects lead to dental problems such as dental deformities, hypomineralization and periodontal impairment. Primarily, DMP1 is consid...Dentin matrix protein 1(DMP1) is essential to odontogenesis. Its mutations in human subjects lead to dental problems such as dental deformities, hypomineralization and periodontal impairment. Primarily, DMP1 is considered as an extracellular matrix protein that promotes hydroxyapatite formation and activates intracellular signaling pathway via interacting with avb3 integrin. Recent in vitro studies suggested that DMP1 might also act as a transcription factor. In this study, we examined whether full-length DMP1 could function as a transcription factor in the nucleus and regulate odontogenesis in vivo. We first demonstrated that a patient with the DMP1M1 V mutation, which presumably causes a loss of the secretory DMP1 but does not affect the nuclear translocation of DMP1, shows a typical rachitic tooth defect. Furthermore, we generated transgenic mice expressingNLSDMP1, in which the endoplasmic reticulum(ER) entry signal sequence of DMP1 was replaced by a nuclear localization signal(NLS) sequence, under the control of a 3.6 kb rat type I collagen promoter plus a 1.6 kb intron 1. We then crossbred theNLSDMP1 transgenic mice with Dmp1 null mice to express the NLSDMP1 in Dmp1-deficient genetic background. Although immunohistochemistry demonstrated thatNLSDMP1 was localized in the nuclei of the preodontoblasts and odontoblasts, the histological, morphological and biochemical analyses showed that it failed to rescue the dental and periodontal defects as well as the delayed tooth eruption in Dmp1 null mice. These data suggest that the full-length DMP1 plays no apparent role in the nucleus during odontogenesis.展开更多
目的探讨牙本质基质蛋白1糖基化形式(proteoglycan form of dentin matrix protein 1,DMP1-PG)在下颌骨骨损伤中的重要作用。方法分别构建对照组野生型(wild type,WT)小鼠及实验组牙本质基质蛋白1糖基化点突变(S89G-DMP1)小鼠下颌骨骨...目的探讨牙本质基质蛋白1糖基化形式(proteoglycan form of dentin matrix protein 1,DMP1-PG)在下颌骨骨损伤中的重要作用。方法分别构建对照组野生型(wild type,WT)小鼠及实验组牙本质基质蛋白1糖基化点突变(S89G-DMP1)小鼠下颌骨骨缺损模型。模型构建完成后7 d、14 d及28 d收取样本,显微计算机断层micro-CT扫描,组织切片及染色,观察二者之间组织愈合差异;通过免疫荧光染色,观察成骨相关蛋白在组织损伤区的表达变化差异;应用实时定量聚合酶链反应(real-time quantitative polymerase chain reaction,RT-qPCR)技术,对比实验组与对照组在术后成骨相关基因表达变化情况;分别提取实验组与对照组颌骨骨髓间充质干细胞,进行成骨诱导分化,观察二者之间成骨分化能力差异。结果同对照组相比,实验组小鼠下颌骨损伤愈合能力明显减弱,骨损伤区成骨相关蛋白表达减低,术后7 d及14 d成骨相关基因表达水平较对照组明显下调。通过提取两组小鼠下颌骨骨髓间充质干细胞进行成骨诱导分化,结果显示同对照组相比,实验组小鼠骨髓间充质干细胞成骨向分化能力明显减弱。结论DMP1-PG参与颌骨损伤修复,缺乏DMP1-PG可导致小鼠颌骨缺损愈合延迟。展开更多
目的探讨维持性血液透析(maintenance hemodialysis,MHD)患者血清牙本质基质蛋白1(dentin matrix protein 1,DMP1)与矿物质代谢及骨密度的关系。方法以2019年7月~2020年7月于青岛大学附属青岛市市立医院血液净化中心行MHD治疗的95名患...目的探讨维持性血液透析(maintenance hemodialysis,MHD)患者血清牙本质基质蛋白1(dentin matrix protein 1,DMP1)与矿物质代谢及骨密度的关系。方法以2019年7月~2020年7月于青岛大学附属青岛市市立医院血液净化中心行MHD治疗的95名患者作为研究对象。收集研究对象的临床资料和实验室检查结果,ELISA测定血清DMP1水平,双能X线吸收法检测MHD患者股骨颈骨密度。采用Spearman相关性分析、多元线性回归分析MHD患者血清DMP1水平的影响因素。二元Logistic回归分析MHD患者发生骨密度低下的影响因素。结果①MHD患者的血清DMP1水平低于健康人群,差异有统计学意义(Z=-3.218,P=0.001)。②Spearman相关性分析显示DMP1水平与年龄、透析龄呈负相关,与肾小球滤过率(eGFR)、甲状旁腺激素(PTH)、股骨颈骨密度T值呈正相关(r值分别为-0.226,-0.223,0.210,0.294,0.370;P值分别为0.028,0.030,0.041,0.004,<0.001)。多元线性回归分析显示,血清DMP1水平的独立影响因素是PTH和股骨颈骨密度T值(β值分别为0.211,0.399;P值分别为0.032,0.001)。③二元Logistic回归分析显示,在调整了年龄、透析龄、白蛋白、碱性磷酸酶和血钙等混杂因素后,血清高DMP1水平是MHD患者发生骨密度低下的独立保护因素(OR:0.913,95%CI:0.845~0.986,P=0.020)。结论MHD患者的血清DMP1水平较健康人群低,且与矿物质代谢及骨密度相关。展开更多
基金supported by NIH grants Jian-Quan Feng (DE018486) and to Chun-Lin Qin (DE005092)State Key Laboratory of Oral Diseases Open Funding (SKLODOF2010-03) to Jian-Quan Feng
文摘Deletion or mutation of dentin matrix protein 1 (DMP1) leads to hypophosphatemic rickets and defects within the dentin. However, it is largely unknown if this pathological change is a direct role of DMP1 or an indirect role of phosphate (Pi) or both. It has also been previously shown that Klotho-deficient mice, which displayed a high Pi level due to a failure of Pi excretion, causes mild defects in the dentinal structure. This study was to address the distinct roles of DMP1 and Pi homeostasis in cell differentiation, apoptosis and mineralization of dentin and enamel. Our working hypothesis was that a stable Pi homeostasis is critical for postnatal tooth formation, and that DMP1 has an antiapoptotic role in both amelogenesis and dentinogenesis. To test this hypothesis, Dmp1-null (Dmp1 2/2 ), Klotho-deficient (kl/kl), Dmp1/Klotho-double-deficient (Dmp1 2/2 /kl/kl) and wild-type (WT) mice were killed at the age of 6 weeks. Combinations of X-ray, microcomputed tomography (mCT), scanning electron microscopy (SEM), histology, apoptosis and immunohistochemical methods were used for characterization of dentin, enamel and pulp structures in these mutant mice. Our results showed that Dmp1 2/2 (a low Pi level) or kl/kl (a high Pi level) mice displayed mild dentin defects such as thin dentin and a reduction of dentin tubules. Neither deficient mouse line exhibited any apparent changes in enamel or pulp structure. However, the double-deficient mice (a high Pi level) displayed severe defects in dentin and enamel structures, including loss of dentinal tubules and enamel prisms, as well as unexpected ectopic ossification within the pulp root canal. TUNEL assay showed a sharp increase in apoptotic cells in ameloblasts and odontoblasts. Based on the above findings, we conclude that DMP1 has a protective role for odontoblasts and ameloblasts in a pro-apoptotic environment (a high Pi level).
基金supported by NIH grants DE018486 and R56 DE022789 to Jian-Quan Feng, DE023365 to Yong-Bo Lu and a scholarship from the Chinese State Scholarship Fund to Shu-Xian Lin (2010627108)
文摘Dentin matrix protein 1(DMP1) is essential to odontogenesis. Its mutations in human subjects lead to dental problems such as dental deformities, hypomineralization and periodontal impairment. Primarily, DMP1 is considered as an extracellular matrix protein that promotes hydroxyapatite formation and activates intracellular signaling pathway via interacting with avb3 integrin. Recent in vitro studies suggested that DMP1 might also act as a transcription factor. In this study, we examined whether full-length DMP1 could function as a transcription factor in the nucleus and regulate odontogenesis in vivo. We first demonstrated that a patient with the DMP1M1 V mutation, which presumably causes a loss of the secretory DMP1 but does not affect the nuclear translocation of DMP1, shows a typical rachitic tooth defect. Furthermore, we generated transgenic mice expressingNLSDMP1, in which the endoplasmic reticulum(ER) entry signal sequence of DMP1 was replaced by a nuclear localization signal(NLS) sequence, under the control of a 3.6 kb rat type I collagen promoter plus a 1.6 kb intron 1. We then crossbred theNLSDMP1 transgenic mice with Dmp1 null mice to express the NLSDMP1 in Dmp1-deficient genetic background. Although immunohistochemistry demonstrated thatNLSDMP1 was localized in the nuclei of the preodontoblasts and odontoblasts, the histological, morphological and biochemical analyses showed that it failed to rescue the dental and periodontal defects as well as the delayed tooth eruption in Dmp1 null mice. These data suggest that the full-length DMP1 plays no apparent role in the nucleus during odontogenesis.
文摘目的探讨维持性血液透析(maintenance hemodialysis,MHD)患者血清牙本质基质蛋白1(dentin matrix protein 1,DMP1)与矿物质代谢及骨密度的关系。方法以2019年7月~2020年7月于青岛大学附属青岛市市立医院血液净化中心行MHD治疗的95名患者作为研究对象。收集研究对象的临床资料和实验室检查结果,ELISA测定血清DMP1水平,双能X线吸收法检测MHD患者股骨颈骨密度。采用Spearman相关性分析、多元线性回归分析MHD患者血清DMP1水平的影响因素。二元Logistic回归分析MHD患者发生骨密度低下的影响因素。结果①MHD患者的血清DMP1水平低于健康人群,差异有统计学意义(Z=-3.218,P=0.001)。②Spearman相关性分析显示DMP1水平与年龄、透析龄呈负相关,与肾小球滤过率(eGFR)、甲状旁腺激素(PTH)、股骨颈骨密度T值呈正相关(r值分别为-0.226,-0.223,0.210,0.294,0.370;P值分别为0.028,0.030,0.041,0.004,<0.001)。多元线性回归分析显示,血清DMP1水平的独立影响因素是PTH和股骨颈骨密度T值(β值分别为0.211,0.399;P值分别为0.032,0.001)。③二元Logistic回归分析显示,在调整了年龄、透析龄、白蛋白、碱性磷酸酶和血钙等混杂因素后,血清高DMP1水平是MHD患者发生骨密度低下的独立保护因素(OR:0.913,95%CI:0.845~0.986,P=0.020)。结论MHD患者的血清DMP1水平较健康人群低,且与矿物质代谢及骨密度相关。
