Novel bone specific pharmacological treatment for osteogenesis imperfecta

项目摘要 成骨不全(OI或脆性骨病)是最常见的遗传性疾病，目前还没有治愈方法 影响1：15,000名新生儿的骨骼疾病。OI最明显的临床特征是骨脆性和骨骼 畸形。OI的主要原因是I型胶原的缺陷，导致胶原分子折叠不当， 破坏原纤维的排列和结构，并为骨骼中的矿化提供异常模板。为了这个 原因是，OI传统上被认为是一种骨细胞外基质疾病，目前OI的治疗方法 依赖药理药物的使用，主要是双膦类药物，这类药物抑制骨吸收 用于骨质疏松症的治疗。尽管最初取得了成功，但这些药物的实际疗效 降低骨折风险的治疗方法存在争议，长期使用可能会产生额外的风险 该药用于发育OI患儿的骨骼。最近的研究表明，一种细胞成分可以 OI病：OI骨的成骨细胞内质网应激。我们最近还发现， 使用4-苯基丁酸酯(4PBA)对内质网应激的药理作用能够减少OI表型 严重，增加骨形成和减少骨骼畸形。这种药物治疗需要两次 改进：1)增加其稳定性；2)使其能够有效地到达骨骼。此外，未知的 是治疗对骨质量和力学的影响。 拟议实验的基本原理是合成一种4PBA衍生物，N-苄基甘氨酸(N-BG)，即 更稳定，并确定其对OI ER细胞应力和OI骨材料性能的影响。一秒钟内 实验中，我们将测试载体((GFO)8)将N-BG输送到骨细胞的效果以及对OI骨的影响 质量。我们将使用原代分离的Brtl小鼠OI模型的成骨细胞来体外检测ER和 N-BG诱导的细胞凋亡应激。隐性(p3h1-/-)和显性(吉娃娃)型的斑马鱼模型，以及 健康的斑马鱼将被注射安慰剂或N-BG药物或(GFO)8-N-BG药物+载体。形态学 将分析处理过的斑马鱼和c的尾前椎的组织孔隙度。 吸毒缠身 治疗后对胶原纤维组织、骨组织成分和力学性能进行检测 利用一系列高分辨率的实验。 从这项研究中获得的知识将为疗效提供信息 关于新的4PBA衍生物疗法以及使用载体治疗OI的骨脆性。这项工作还将 为斑马鱼骨骼病模型的药物疗效评价提供首个标准化的流水线。

Project Summary There is no cure for osteogenesis imperfecta (OI or brittle bone disease), the most common of the heritable disorders of bone affecting 1:15,000 births. The most evident clinical hallmarks of OI is bone fragility and skeletal deformities. OI is caused primarily by defects in collagen type I, leading to collagen molecules folding improperly, disrupting fibril alignment and structure, and providing an abnormal template for mineralization in bone. For this reason, OI has been traditionally considered a bone extracellular matrix disorder, and current treatments for OI rely on the use of pharmacological drugs, mainly bisphosphonates, a class of drugs that inhibit bone resorption and is used in the management of osteoporosis. Despite the initial success, the actual efficacy of these treatments to reduce the fracture risk are controversial and additional risks may arise from the long-term use of this drug in developing bones of children with OI. Recent research has demonstrated a cellular component to the OI disease: the endoplasmic reticulum (ER) stress in the osteoblasts of OI bone. We also recently found that pharmacological action toward ER stress using the 4-phenyl butyrate (4PBA) is able to reduce the OI phenotype severity, increasing bone formation and reducing skeletal deformities. This drug treatment needs two improvements: 1) increase its stability and 2) make it able to effectively reach the bone. Furthermore, unknown is the effect of the treatment on bone quality and mechanics. The rationale of the proposed experiments is to synthesize a 4PBA derivative, the N-benzyl glycine (N-BG), that is more stable and to determine its effect on OI ER cells stress and on OI bone material properties. In a second experiment, we will test the efficacy of a carrier ((GfO)8) to deliver N-BG to bone cells and the effect on OI bone quality. We will use primary isolated osteoblasts from Brtl mouse model of OI for the in vitro testing of ER and apoptotic stress with N-BG. Zebrafish models of recessive (p3h1-/-) and dominant (Chihuahua) type of OI, and healthy zebrafishes will be injected with either placebo or N-BG drug or (GfO)8-N-BG drug+carrier. Morphology and tissue porosity of precaudal vertebrae will be analyzed in the treated zebrafishes and the c hanges with drug therapy to the collagen fiber organization, bone tissue composition and mechanical properties will be examined using an array of high resolution experiments. The knowledge gained from this study will inform on the efficacy of new 4PBA derivatives therapies and on the use of carriers to treat bone fragility in OI. This work will also provide the first and standardized pipeline to evaluate drug effect on Zebrafish skeletal disease models.