Clinical Research of Oral Connective Tissue Program

口腔结缔组织项目临床研究

• 批准号: 10006390
• 负责人: Martha Somerman
• 金额: $ 17.88万
• 依托单位: NATIONAL INSTITUTE OF ARTHRITIS AND MUSCULOSKELETAL AND SKIN DISEASES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10006390
• 关键词: Affect; Age; Alkaline Phosphatase; Ankylosis; Binding; C-terminal; Candidate Disease Gene; Cells; Cementocyte; Cementogenesis; Cervical; Chicago; Clinical; Clinical Research; Collaborations; Connective Tissue; Data; Daughter; Dental; Dental Cementum; Dental Enamel; Dental caries; Dentin; Development; Diagnosis; Diagnostic radiologic examination; Diphosphates; Disease; Epigenetic Process; Exhibits; Extramural Activities; Family member; Fostering; Gene Proteins; Genes; Genetic Predisposition to Disease; Genetic screening method; Histologic; Histology; IFN consensus sequence binding protein; Individual; Institutional Review Boards; Knockout Mice; Lead; Link; Maintenance; Maryland; Mathematics; Medical History; Metabolic Diseases; Metabolism; Minerals; Missense Mutation; Molecular Analysis; Morphology; Mutation; National Institute of Dental and Craniofacial Research; Natural regeneration; Newborn Infant; North Carolina; Ohio; Oral; Orthodontic; Osteoclasts; Osteolysis; Pathology; Patients; Pattern; Phenotype; Plant Roots; Primary Dentition; Proteins; Protocols documentation; Publishing; Recording of previous events; Reporting; Research Personnel; Roentgen Rays; Root Resorption; Saliva; Sampling; School Dentistry; Skeleton; Son; Structure; Thick; Tissues; Tooth Movement; Tooth Tissue; Tooth root structure; Tooth structure; United States National Institutes of Health; Universities; Work; aged; arterial calcification of infancy; base; craniofacial complex; deciduous tooth; density; exome sequencing; extracellular; gene function; human subject; inorganic phosphate; kindred; loss of function mutation; member; microCT; microbial; mineralization; novel; permanent tooth; plasma cell membrane glycoprotein PC-1; proband; programs; repaired

Project A. Determine genetic susceptibility and immunopathological mechanisms contributing to idiopathic tooth root resorption Background: Previously, we reported that BSP KO mice exhibit a tooth root resorption phenotype. Based on this finding, we sought to identify human subjects exhibiting multiple idiopathic cervical root resorption (MICRR), a familial pattern of MICRR with suggested genetic susceptibility. Following IRB approval from the University of Detroit Mercy School of Dentistry and NIH, dental/medical histories, x-rays, saliva samples, and extracted teeth were collected from a kindred (4 affected and 4 unaffected members) exhibiting MICRR. On examination, the proband and the affected son and daughter exhibited severe root resorption of multiple teeth, with no other significant medical history. Micro-CT of exfoliated teeth revealed severe cervical root resorption distinct from tooth decay. Whole exome sequencing using saliva from affected and unaffected family members identified SNPs in ten candidate genes that co-segregated with the resorption phenotype, including a novel autosomal dominant missense mutation in the Interferon Regulatory Factor 8 (IRF8) gene. Detailed analysis identified a mutation in the c-terminal region of IRF8 responsible for overactive osteoclast function. Results were published in JBMR, 2019 (see below). This project transitioned to University Maryland with Dr. Thumbigere-Math (K99/R00 recipient). Ongoing: We continue to collaborate with Dr. Thumbigere-Math as the lead on the IRF8 project, with other NIH IRF8 collaborators, Drs. Ozato and Holland. In addition, we have established a collaboration with a periodontist in Chicago, IL, Dr. Steve Russo related to a patient of his that developed idiopathic root resorption within a two-year period (2017-2019). We will be analyzing teeth, tissues, saliva and plaque samples. We have set up a collaboration with an expert in microbial analyses, Dr. Purnima Kumar at the Ohio State University, to determine the microbial profile of plaque samples from this patient. Further, we are working with Dr. Betty Hajishengallis at U. Penn related to a patient with missing ossicles and idiopathic root resorption. The patient, aged 10 yrs., recently had genetic testing and was diagnosed with familial expansile osteolysis. We are working with Dr. Hajishengallis to determine the mechanism for root resorption, including a potential link to alternations in specific genes noted in this patient. Project B. Disorders of mineralization: In collaboration with NIDCR clinical researchers and other IC clinicians, we have been examining individuals with mineralized tissue metabolism disorders for alterations in tissues/cells of the DOC complex. 1.Mutations in key regulators of Pi/PPi. Mineralization of skeleton and teeth is tightly regulated by levels of extracellular inorganic phosphate (Pi) and pyrophosphate (PPi). Three regulators that control pericellular concentrations of Pi and PPi include tissue-nonspecific alkaline phosphatase (TNAP), progressive ankylosis protein (ANK), and ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1). Inactivation of these factors results in mineralization disorders affecting teeth and their supporting structures. We examined the effect of decreased PPi on development and maturation of teeth in human subjects (4) with generalized arterial calcification of infancy (GACI), who harbor loss-of-function mutations in the ENPP1 gene. Three of the four subjects reported a history of infraocclusion or over-retained primary teeth or poor orthodontic tooth movement, suggesting altered mineral metabolism as a contributing factor. All subjects presented radiographic evidence of unusually protruding cervical root morphology in primary and/or secondary dentitions. Micro-CT analyses of extracted primary teeth from two GACI subjects revealed marked increase cervical cementum thickness and density vs. age-matched healthy control teeth. There were no differences in enamel and dentin densities between GACI and control teeth. Histology revealed dramatically expanded cervical cementum in GACI teeth, including cementocyte-like cells and unusual patterns of cementum resorption and repair. Micro-CT analysis of Enpp1 knock-out mouse molars revealed a marked increase in acellular cementum thickness and volume. Collectively, these findings report a novel dental phenotype in GACI and further support our hypothesis that Pi/PPi modulation is as a key mechanism for regulating cementogenesis across species. Thumbigere-Math V et al., JDR, 2018. Ongoing: We have continued to examine patients with Pi/PPi disorders at NIH CRC as well as analyzing exfoliated or extracted teeth from patients with Pi/PPi disorders. We have also included patients with ABCC6 (ATP Binding Cassette Subfamily C Member 6), which is associated with some cases of GACI. For controls, in collaboration with North Carolina State University and Duke under the Newborn Epigenetics Study, we are obtaining exfoliated primary teeth from healthy individuals.

项目 A. 确定导致特发性牙根吸收的遗传易感性和免疫病理学机制 背景：之前，我们报道了 BSP KO 小鼠表现出牙根吸收表型。基于这一发现，我们试图识别表现出多发性特发性颈根吸收（MICRR）的人类受试者，这是一种具有遗传易感性的 MICRR 家族模式。经底特律大学梅西牙科学院和 NIH 的 IRB 批准后，从表现出 MICRR 的亲属（4 名受影响成员和 4 名未受影响成员）收集了牙科/病史、X 射线、唾液样本和拔牙。经过检查，先证者和受影响的儿子和女儿表现出多颗牙齿的严重牙根吸收，没有其他明显的病史。脱落牙齿的显微 CT 显示严重的颈根吸收，与蛀牙不同。使用受影响和未受影响的家庭成员的唾液进行全外显子组测序，确定了与吸收表型共分离的 10 个候选基因中的 S​​NP，其中包括干扰素调节因子 8 (IRF8) 基因中的一种新型常染色体显性错义突变。详细分析发现 IRF8 C 端区域的突变导致破骨细胞功能过度活跃。结果发表于 JBMR，2019（见下文）。该项目由 Thumbigere-Math 博士（K99/R00 获得者）转移到马里兰大学。 正在进行中：我们继续与作为 IRF8 项目领导者的 Thumbigere-Math 博士以及其他 NIH IRF8 合作者 Drs. Thumbigere-Math 合作。小里和荷兰。此外，我们还与伊利诺伊州芝加哥的牙周病专家 Steve Russo 博士建立了合作关系，他的一名患者在两年内（2017-2019 年）出现特发性牙根吸收。我们将分析牙齿、组织、唾液和牙菌斑样本。我们与微生物分析专家、俄亥俄州立大学的 Purnima Kumar 博士建立了合作，以确定该患者牙菌斑样本的微生物特征。此外，我们正在与宾夕法尼亚大学的 Betty Hajishengallis 博士合作，治疗一名小骨缺失和特发性牙根吸收的患者。该患者年龄10岁，最近进行基因检测，被诊断为家族性扩张性骨溶解症。我们正在与 Hajishengallis 博士合作，以确定牙根吸收的机制，包括与该患者注意到的特定基因改变的潜在联系。 项目 B. 矿化紊乱： 我们与 NIDCR 临床研究人员和其他 IC 临床医生合作，一直在检查患有矿化组织代谢紊乱的个体 DOC 复合体组织/细胞的变化。 1.Pi/PPi关键调控因子突变。骨骼和牙齿的矿化受到细胞外无机磷酸盐 (Pi) 和焦磷酸盐 (PPi) 水平的严格调节。 控制 Pi 和 PPi 细胞周浓度的三种调节因子包括组织非特异性碱性磷酸酶 (TNAP)、进行性强直蛋白 (ANK) 和外核苷酸焦磷酸酶/磷酸二酯酶 1 (ENPP1)。 这些因素的失活会导致影响牙齿及其支撑结构的矿化障碍。 我们研究了 PPi 减少对患有婴儿期广泛动脉钙化 (GACI) 人类受试者 (4) 牙齿发育和成熟的影响，这些受试者的 ENPP1 基因具有功能丧失突变。 四名受试者中的三名报告有咬合不良或乳牙过度固位或正畸牙齿移动不良的病史，表明矿物质代谢改变是一个促成因素。 所有受试者的乳牙和/或次生牙列均呈现出异常突出的颈根形态的放射学证据。对两名 GACI 受试者拔出的乳牙进行显微 CT 分析显示，与年龄匹配的健康对照牙齿相比，颈椎牙骨质厚度和密度显着增加。 GACI 牙齿和对照牙齿之间的牙釉质和牙本质密度没有差异。 组织学显示 GACI 牙齿中的颈牙骨质显着扩张，包括牙骨质细胞样细胞和牙骨质吸收和修复的异常模式。 对 Enpp1 敲除小鼠磨牙的显微 CT 分析显示，脱细胞牙骨质厚度和体积显着增加。 总的来说，这些发现报告了 GACI 中的一种新的牙齿表型，并进一步支持了我们的假设，即 Pi/PPi 调节是调节跨物种牙骨质形成的关键机制。 Thumbigere-Math V 等人，JDR，2018。 正在进行中：我们继续在 NIH CRC 检查患有 Pi/PPi 疾病的患者，并分析患有 Pi/PPi 疾病的患者脱落或拔除的牙齿。 我们还纳入了 ABCC6（ATP 结合盒亚家族 C 成员 6）患者，该患者与某些 GACI 病例相关。 作为对照，我们与北卡罗来纳州立大学和杜克大学合作进行新生儿表观遗传学研究，从健康个体中获取脱落的乳牙。