Molecular and genetic characterization of the Sorting Nexin 10 R51Q mutation and other mutations, causing osteopetrosis in infancy in Palestinian clans

导致巴勒斯坦部族婴儿期骨硬化症的分选 Nexin 10 R51Q 突变和其他突变的分子和遗传特征

• 批准号: 279908667
• 负责人: Professor Dr. Jan Tuckermann
• 金额: --
• 依托单位: Institut für Molekulare Endokrinologie der Tiere
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2016
• 资助国家: 德国
• 起止时间: 2015-12-31 至 2021-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/279908667?language=en
• 关键词: Molecular; genetic; characterization; Sorting; Nexin

Autosomal recessive osteopetrosis (ARO) is a severe inherited disease in infants due to aberrant bone growth caused by defects in bone resorption. ARO is a rare disease, but with high prevalence in consanguineous populations. 2012 a point mutation in the Sorting Nexin 10 (SNX10) gene was discovered in Palestinian endemic populations leading to an arginin/glutamin exchange (SNX10 R51Q). Since then different mutations in the SNX10 gene causing osteopetrosis were identified all over the world. Gold-standard treatment of ARO is the transplantation of healthy hematopoietic stem cells in order to rescue the defect of the bone resorbing osteoclasts with wild type cells. However, a successful therapy is hampered by late diagnosis of the disease and subsequent late transplantation, the unknown effect of heterozygous donor cells, a low donor chimerism upon transplantation, and unknown effects of the mutation possibly contributing to pathologies in patients after transplantation. We therefore generated a highly translational approach to unravel the etiology of ARO caused by SNX10 R51Q, by investigating population genetics, developing transgenic mouse models for the SNX10 R51Q disease and by analysing the cell biological mechanisms of osteoclast failure. In the first funding period we achieved in the first 16 months substantial progress in our trilateral interdisciplinary research consortium from Palestine, Germany and Israel. We increased awareness of the population and local government towards genetic counseling for the disease. We successfully mapped SNPs and STRs to the locus, detected new affected families and discovered so far unknown mutations in ARO. With the generation of SNX10 R51Q Knock-In mice we established the first Knock-In mouse model for an ARO mutation closely resembling the patient phenotype. We discovered a novel osteoclast phenotype that displays unlimited fusion and thus leads to non-functional resorption. This discovery points towards fundamental questions of osteoclast fusion that are still unclear but are important beyond osteopetrosis for common diseases such as osteoporosis and cancer. We now aim in a bench to bed side translation and back approach to characterize genetic frequencies of the SNX10 R51Q- and one novel mutation in the Palestine population. We will dissect the osteoclast autonomous and non-autonomous function in SNX10 R51Q Knock-In and SNX10 complete Knock-Out mice using bone marrow chimeric mouse models. These experiments will give insight in SNX10-related pathologies occuring in patients even after transplantation. And finally we will carefully analyze the molecular mechanisms of SNX10 in general and SNX10 R51Q in particular in the osteoclast fusion process and how mixed fusions of wild type cells and mutant cells affect the fusion process, a situation that might occur in patients upon transplantations. Our insights will be of direct benefit for the patients and will give implications for bone biology in general.

常染色体隐性遗传性石骨症（ARO）是一种严重的遗传性疾病，由于异常的骨生长引起的骨吸收缺陷的婴儿。ARO是一种罕见的疾病，但在近亲人群中的患病率很高。2012年，在巴勒斯坦流行病人群中发现了Sorting Nexin 10（SNX 10）基因的点突变，导致了Bronchin/Bronchamin交换（SNX 10 R51 Q）。从那时起，世界各地都发现了导致骨硬化症的SNX 10基因的不同突变。ARO的金标准治疗是移植健康的造血干细胞，以便用野生型细胞挽救骨吸收破骨细胞的缺陷。然而，成功的治疗受到疾病的晚期诊断和随后的晚期移植、杂合供体细胞的未知影响、移植后的低供体嵌合性以及可能导致移植后患者病理的突变的未知影响的阻碍。因此，我们通过研究群体遗传学，开发SNX 10 R51 Q疾病的转基因小鼠模型和分析破骨细胞失败的细胞生物学机制，产生了一种高度翻译的方法来解开SNX 10 R51 Q引起的ARO的病因。在第一个资助期内，我们在前16个月内在巴勒斯坦、德国和以色列的三边跨学科研究联合体中取得了实质性进展。我们提高了民众和地方政府对该病遗传咨询的认识。我们成功地将SNP和STR定位到该位点，检测到新的受影响家族，并发现了迄今为止未知的ARO突变。随着SNX 10 R51 Q敲入小鼠的产生，我们建立了第一个与患者表型非常相似的ARO突变的敲入小鼠模型。我们发现了一种新的破骨细胞表型，显示无限融合，从而导致非功能性吸收。这一发现指出了破骨细胞融合的基本问题，这些问题仍然不清楚，但对常见疾病如骨质疏松症和癌症的骨硬化症很重要。我们现在的目标是在一个工作台到床边翻译和回的方法来表征SNX 10 R51 Q的遗传频率-和一个新的突变在巴勒斯坦人口。我们将使用骨髓嵌合体小鼠模型来解剖SNX 10 R51 Q敲入和SNX 10完全敲除小鼠中破骨细胞自主和非自主功能。这些实验将使人们了解移植后患者中发生的SNX 10相关病理。最后，我们将仔细分析SNX 10在破骨细胞融合过程中的分子机制，特别是SNX 10 R51 Q，以及野生型细胞和突变细胞的混合融合如何影响融合过程，这种情况可能发生在移植患者中。我们的见解将对患者直接有益，并将对骨生物学产生影响。