Understanding the skeletal phenotype of Gaucher disease

了解戈谢病的骨骼表型

基本信息

批准号：
8654067
负责人：
PRAMOD K MISTRY
金额：
$ 59.15万
依托单位：
ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-09-16 至 2018-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8654067
关键词：
Adamantane Affect Apoptosis Ashkenazim Autoimmune Process Automobile Driving Bone Diseases Bone Resorption Catabolism Cell Culture Techniques Cell Cycle Cell Lineage Cells Ceramide glucosyltransferase Ceramides Collaborations Data Defect Disease Disease susceptibility Embryo Employee Strikes Enzymes Exposure to Fracture Functional disorder Gaucher Disease Genes Genetic Genets Glucosylceramides Glycoside Hydrolases Goals Hematopoietic Hepatosplenomegaly Hereditary Disease Human Immune In Vitro Incidence Infiltration Investigation Knock-in Mouse Lipids Live Birth Malignant Neoplasms Marrow Mediating Mesenchymal Molecular Mus Mutation Neoplasms Nerve Degeneration Non-Neuronopathic Gaucher Disease Osteoblasts Osteoclasts Osteocytes Osteogenesis Osteopenia Osteoporosis Pathway interactions Patients Phenocopy Phenotype Population Risk Role Serum Sphingolipids Sphingosine Stromal Cells Tartrates Visceral Visceromegaly base bone bone cell bone loss bone turnover cell type cytokine cytopenia dentin matrix protein 1 enzyme replacement therapy follower of religion Jewish glucosylceramidase glucosylsphingosine high risk human disease imiglucerase in vivo inhibitor/antagonist medical schools mouse model mutant new therapeutic target novel osteoblast differentiation promoter public health relevance skeletal skeletal disorder sphingosine 1-phosphate tool

项目摘要

DESCRIPTION (provided by applicant): Gaucher Disease is a debilitating lysosomal storage disorder characterized by striking visceral enlargement and a high risk of crippling fractures. It s caused by mutations in the glucocerebrosidase (GBA1) gene that impair -glycosidase, an enzyme required for sphingolipid catabolism. While enzyme replacement therapy (imiglucerase) is effective, its effects on fracture risk are not fully understood. To identify new therapeutic targets for non-neuronopathic type 1 GD (GD1), attempts have been made to knock in mutations and delete Gba1 in mice. We have successfully deleted Gba1 in cells of the hematopoietic and mesenchymal cell lineage using an Mx1 promoter. Our Mx1-Cre:GD1 mouse phenocopies human GD1 almost in its entirety, displaying severe hepatosplenomegaly, cytopenia, and osteoporosis. The mouse also displays Th1 and Th2 hypercytokinemia and immune cell defects, which might contribute not only to the increased risk of lymphoproliferative malignancy, but also to the bone disease. Our data further show that the osteoporosis is due to a defect in osteoblastic bone formation, not osteoclastic bone resorption. We find that reduced osteoblast viability noted in stromal cell cultures from Mx1-Cre:GD1 mice is recapitulated by exposure to sphingosine, a sphingolipid that accumulates in GD1. We hypothesize that, despite the immune cell dysfunction that may affect bone, the osteopenia noted in Mx1-Cre:GD1 mice arises mainly from the direct action of sphingosine on the osteoblast, thus lowering bone formation. Therefore, in Specific Aim 1, we will determine whether the bone formation defect is autonomous, and if so, which bone cell - osteoblast, osteocyte, or osteoclast - drives it. For this we will delete Gba1 in the three cell types, respectively, using Col2.3-Cre, Dmp1-Cre and CathK-Cre mice. In Specific Aim 2, we will lower sphingolipid levels by inhibiting or deleting glucosylceramide synthase (Gcs), an enzyme upstream of Gba1. For this, we will inject Mx1-Cre:GD1 mice with eliglustat tartrate, a Gcs inhibitor, and, in parallel, generate mice lacking Gba1 and Gcs in the same cells. Of note, we find that eliglustat tartrate lowers serum GL-1 and reverses the visceromegaly and cytopenia in GD1 patients. Finally, in Specific Aim 3, to hone in on the specific lipid that causes osteoblast inhibition, we will lower sphingosine, but not LysoGL-1 levels. We hypothesize that, as the extralysosomal enzyme Gba2 converts LysoGL-1 to sphingosine, Gba2 deletion or its inhibition by AMP-DNM should reverse the osteopenia in Mx1-Cre:GD1 mice. To further examine the action of sphingosine and other sphingolipids on the osteoblast, we will study differentiation, cell cycling and apoptosis in vitro. Our investigations should not only define the target cell and responsible molecule for the osteopenia in GD1, but also identify new therapeutic targets, both upstream (Gcs) and downstream (Gba2) of Gba1, for GD1-associated and other common types of osteoporosis.

描述（由申请人提供）：戈谢病是一种使人衰弱的溶酶体贮积症，其特征是内脏显着增大和致残性骨折的高风险。它是由葡萄糖脑苷脂酶 (GBA1) 基因突变引起的，该突变会损害β-糖苷酶，而β-糖苷酶是鞘脂分解代谢所需的酶。虽然酶替代疗法（伊米苷酶）有效，但其对骨折风险的影响尚不完全清楚。为了确定非神经病性 1 型 GD (GD1) 的新治疗靶点，人们尝试在小鼠中敲入突变并删除 Gba1。我们使用 Mx1 启动子成功删除了造血细胞和间充质细胞系细胞中的 Gba1。我们的 Mx1-Cre:GD1 小鼠表型几乎完全模仿人类 GD1，表现出严重的肝脾肿大、血细胞减少和骨质疏松症。小鼠还表现出 Th1 和 Th2 高细胞因子血症和免疫细胞缺陷，这不仅可能导致淋巴增殖性恶性肿瘤的风险增加，而且可能导致骨病。我们的数据进一步表明，骨质疏松症是由于成骨细胞骨形成缺陷所致，而不是破骨细胞骨吸收缺陷。我们发现，在 Mx1-Cre:GD1 小鼠的基质细胞培养物中发现的成骨细胞活力降低，可以通过暴露于鞘氨醇（一种在 GD1 中积累的鞘脂）来重现。我们假设，尽管免疫细胞功能障碍可能影响骨骼，但 Mx1-Cre:GD1 小鼠中注意到的骨质减少主要是由于鞘氨醇对成骨细胞的直接作用，从而降低了骨形成。因此，在具体目标 1 中，我们将确定骨形成缺陷是否是自主的，如果是，则由哪种骨细胞（成骨细胞、骨细胞或破骨细胞）驱动它。为此，我们将使用 Col2.3-Cre、Dmp1-Cre 和 CathK-Cre 小鼠分别删除三种细胞类型中的 Gba1。在具体目标 2 中，我们将通过抑制或删除葡萄糖神经酰胺合酶 (Gcs)（Gba1 上游的一种酶）来降低鞘脂水平。为此，我们将向 Mx1-Cre:GD1 小鼠注射 eliglustat tartrate（一种 Gcs 抑制剂），并同时在同一细胞中生成缺乏 Gba1 和 Gcs 的小鼠。值得注意的是，我们发现酒石酸 Eliglustat 可降低 GD1 患者的血清 GL-1 并逆转内脏肿大和血细胞减少。最后，在具体目标 3 中，为了研究导致成骨细胞抑制的特定脂质，我们将降低鞘氨醇，但不降低 LysoGL-1 水平。我们假设，当溶酶体外酶 Gba2 将 LysoGL-1 转化为鞘氨醇时，Gba2 缺失或 AMP-DNM 的抑制应能逆转 Mx1-Cre:GD1 小鼠的骨质减少。为了进一步研究鞘氨醇和其他鞘脂对成骨细胞的作用，我们将在体外研究分化、细胞周期和凋亡。我们的研究不仅应该确定 GD1 骨质减少的靶细胞和负责分子，还应该确定 GD1 相关骨质疏松症和其他常见类型骨质疏松症的新治疗靶点，包括 Gba1 的上游 (Gcs) 和下游 (Gba2)。