Pathogenesis of Multicentric Carpotarsal Osteolysis

多中心腕跗骨溶解症的发病机制

• 批准号: 10511593
• 负责人: STEVEN R MUMM
• 金额: $ 20.75万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-22 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10511593
• 关键词: Affect; Age; Ankle; Area; Biological Markers; Birds; Bone remodeling; CRISPR/Cas technology; Caring; Cell Differentiation process; Cell Line; Cell physiology; Cells; Child; Chondrocytes; Clinical; Cytolysis; Data; Defect; Development; Disease; Drug Screening; Elbow; Exons; Extracellular Matrix; Extracellular Matrix Degradation; Extracellular Matrix Proteins; Failure; Family; Forearm; Genes; Hematopoietic; Kidney; Kidney Failure; Knee; Lead; Libraries; Life; Lytic; Matrix Metalloproteinases; Mediating; Methods; Modeling; Mutation; Nature; Oncogenes; Online Mendelian Inheritance In Man; Orthologous Gene; Osteoblasts; Osteocalcin; Osteoclasts; Osteogenesis; Osteolysis; Osteolytic; Osteopenia; Pathogenesis; Patients; Physiologic Ossification; Process; Race; Reporting; Research; Research Personnel; Role; Serum; Shoulder; Signal Pathway; Stromelysin 1; Syndrome; Tarsal Bones; Testing; Thinking; Transactivation; WNT Signaling Pathway; aggrecan; bisphosphonate; bone; bone cell; bone loss; boys; carpus bone; cell type; cohort; effective therapy; fibrosarcoma; girls; human disease; impression; induced pluripotent stem cell; long bone; macrophage; member; monocyte; mouse model; mutant; novel therapeutics; preservation; proband; protease E; protein expression; radiological imaging; response; sex; specific biomarkers; stem cell differentiation; success; therapy development; transcription factor

Abstract Multicentric carpotarsal osteolysis syndrome (MCTO) is an autosomal dominant disorder that incapacitates young children and leads to life-threatening renal failure soon after. Because of its deforming, debilitating, and frequently life-threatening nature, it is understandable why it often arises spontaneously. The clinical and radiographic hallmark is carpal–tarsal bone destruction. Bones in the shoulders, elbows, and knees are also commonly affected by the destructive process. Sometimes there is generalized osteopenia. During the past 30 years, we have cared for eleven unrelated children with MCTO. In 2012, an Australian research group reported mutations within single-exon MAFB [v-maf musculoaponeurotic fibrosarcoma oncogene ortholog B (avian)] in 13 probands with MCTO. Soon after, we reported MAFB mutations for our patient cohort confirming that all MAFB mutations causing MCTO localize to a small region of the transactivation domain. MAFB is a member of the MAF family of transcription factors, and drives osteoclast activity. However, bisphosphonates, which inhibit osteoclasts, are not an effective treatment for MCTO, suggesting other bone cells are also involved. Our preliminary data showed that serum biomarkers for osteoblasts (osteocalcin, SOST, and DKK1) were significantly decreased and MMP3 (expressed in chondrocytes) and MMP7 were elevated in MCTO patients vs. age-matched controls. Therefore, we believe that both osteoblasts and chondrocytes are also affected by MAFB mutation in MCTO. We hypothesize that MCTO results from a combination of 1) defective MMP-driven degradation of the extracellular matrix during endochondral bone formation and 2) excessive osteoclast-driven osteolysis during bone remodeling. We have already developed three patient-derived induced pluripotent stem (iPS) cell lines from patients with different mutations, race, and sex. We will now develop and validate three isogenic control cell lines using CRISPR technology to correct the MAFB mutations. We will then demonstrate that MAFB mutations impact cell differentiation and function by differentiating mutant iPSCs and isogenic control cells into OBs, chondrocytes, and OCs and assessing cell differentiation and function. This will establish the patient-derived iPSC approach as a viable method to elucidate the mechanism of MCTO. This is especially important because the MCTO mouse model does not recapitulate the carpal/tarsal bone loss seen in the human disease. Understanding the mechanism of MCTO will help guide development of therapies. Further, the patient-derived iPSCs and isogenic control cells can be used to screen drug libraries or test new therapies.

抽象的 多中心腕跗骨溶解综合征（MCTO）是一种常染色体显性遗传疾病， 使幼儿丧失行为能力，并很快导致危及生命的肾衰竭。由于它的变形， 其性质使人衰弱，并且经常危及生命，因此它经常自发出现是可以理解的。这 临床和放射学特征是腕骨-跗骨破坏。肩膀、肘部和膝盖的骨头 也通常受到破坏性过程的影响。有时会出现全身性骨质减少。期间 在过去的30年里，我们用MCTO照顾了11名没有血缘关系的孩子。 2012年，澳大利亚研究小组 报道单外显子 MAFB [v-maf 肌肉腱膜纤维肉瘤癌基因直向同源物 B 内的突变 （禽类）] 13 名患有 MCTO 的先证者。不久之后，我们报告了我们的患者队列的 MAFB 突变，证实了这一点 导致 MCTO 的所有 MAFB 突变都定位于反式激活结构域的一小部分区域。 MAFB 是一个 转录因子 MAF 家族的成员，驱动破骨细胞活性。然而，双膦酸盐、 抑制破骨细胞，并不是 MCTO 的有效治疗方法，这表明其他骨细胞也有作用 涉及。我们的初步数据显示，成骨细胞的血清生物标志物（骨钙素、SOST 和 DKK1） MCTO 中 MMP3（在软骨细胞中表达）和 MMP7 显着降低，MMP3 升高 患者与年龄匹配的对照。因此，我们认为成骨细胞和软骨细胞也是 受 MCTO 中 MAFB 突变的影响。我们假设 MCTO 是由 1) 有缺陷的组合导致的 软骨内骨形成过程中 MMP 驱动的细胞外基质降解和 2) 过度降解 骨重塑过程中破骨细胞驱动的骨质溶解。 We have already developed three patient-derived 来自具有不同突变、种族和性别的患者的诱导多能干（iPS）细胞系。我们现在将 使用 CRISPR 技术开发并验证三种同基因对照细胞系以纠正 MAFB 突变。 然后我们将通过区分突变体来证明 MAFB 突变影响细胞分化和功能 iPSC 和同基因对照细胞转化为 OB、软骨细胞和 OC，并评估细胞分化和 功能。这将建立源自患者的 iPSC 方法作为阐明该机制的可行方法 MCTO 的。这一点尤其重要，因为 MCTO 小鼠模型不能重现腕骨/跗骨 骨质流失见于人类疾病。了解MCTO的机制将有助于指导其发展 疗法。此外，源自患者的 iPSC 和同基因对照细胞可用于筛选药物库或 测试新疗法。