Identification of osteoclast endocrine and paracrine communications by systems genetics approaches

破骨细胞的骨吸收在骨骼生长、稳态和骨折修复中起着关键作用。在 在成年人中，骨健康是通过骨重建来确保的，其中骨吸收是通过骨重建来耦合和平衡的。 由成骨细胞形成。因此，破骨细胞的数量和活性受到系统性的严格调节。 激素和旁分泌因子。与此同时，骨头本身也越来越 在全身生理学中，它被认为是一种内分泌器官，可以调节其他器官的功能。 而源自成骨细胞和骨细胞的内分泌因子如FGF 23和TGF-β 1的系统性功能可能与成骨细胞的功能有关。 虽然骨钙素的研究已经很成熟，但破骨细胞分泌蛋白的内分泌功能仍有待进一步研究。 发现了为了识别和功能注释内分泌和旁分泌回路，我们开发了一种新的 系统遗传方法，称为定量内分泌网络相互作用估计（QENIE），利用 在多个“组学”数据集中跨组织转录水平的自然变化，以预测内分泌模式 通信将这种方法应用于杂交小鼠多样性小组（HMDP）中的数据集， 大约100个近交系小鼠表现出与人类相关的大多数临床特征的实质性多样性， 通过研究疾病，我们已经揭示了许多已知的内分泌相互作用以及一些新的组织-组织回路。 在导致这一提议的初步研究中，我们定量测量了蛋白质水平， 通过基于质谱的蛋白质组学和批量RNA-seq在前体和成熟破骨细胞中的RNA。 破骨细胞谱系细胞中的数百种分泌蛋白已通过这些“组学”研究鉴定。而 已知在骨重建过程中刺激骨生成的几种破骨细胞衍生的偶联因子存在于 破骨细胞分泌蛋白的列表，这些新发现的大多数的内分泌和旁分泌功能 破骨细胞分泌蛋白是未知的。根据我们的工作和其他人的报告，我们假设 破骨细胞的内分泌和旁分泌通讯在全身和骨骼中起重要作用 在生理和病理条件下的内稳态。为了验证我们的假设，我们将确定新的 系统遗传学生物信息学框架下破骨细胞谱系细胞的内分泌和旁分泌回路 QENIE（目的1），并通过体外实验验证和功能评估这些破骨细胞衍生因子 细胞培养和共培养模型（目的2）。成功完成本申请中的拟议工作 将制定新的假设，使用体内动物模型和人类群体进行测试。这些发现 从这个项目将不仅大大推进我们在破骨细胞生物学的知识， 用于治疗骨和其他器官疾病中的骨丢失的治疗靶点。

Bone resorption by osteoclasts plays a pivotal role in skeleton growth, homeostasis, and fracture repair. In adults, bone health is ensured by bone remodeling in which bone resorption is coupled and balanced by bone formation from osteoblasts. Therefore, the number and activities of osteoclasts are tightly regulated by systemic hormones and paracrine factors in bone marrow microenvironment. Meanwhile, bone itself is increasingly recognized as an endocrine organ which can modulate functions of other organs in whole-body physiology. While the systemic functions of endocrine factors derived from osteoblasts and osteocytes such as FGF23 and osteocalcin have been well established, the endocrine functions of osteoclast secreted proteins remain to be uncovered. To identify and functionally annotate endocrine and paracrine circuits, we have developed a novel systems genetic approach, termed Quantitative Endocrine Network Interaction Estimation (QENIE), that utilizes natural variation in transcript levels across tissues in multiple ‘omics’ datasets to predict modes of endocrine communication. Applying this approach to datasets in the hybrid mouse diversity panel (HMDP), a collection of approximately 100 inbred strains of mice exhibiting substantial diversity of most clinical traits relevant to human diseases, we have unraveled many known endocrine interactions as well as several novel tissue-tissue circuits. In the preliminary study leading to this proposal, we have quantitatively measured the levels of proteins and RNAs in precursor and mature osteoclasts by mass-spectrometry based proteomic and bulk RNA-seq. Hundreds of secreted proteins in osteoclast lineage cells have been identified by these ‘omics’ studies. While several osteoclast-derived coupling factors known to stimulate osteogenesis during bone remodeling are in the list of osteoclast secreted proteins, the endocrine and paracrine functions of most of these newly identified osteoclast secretory proteins are unknown. Based on our work and reports by others, we hypothesize that the endocrine and paracrine communications of osteoclasts play an important role in whole body and bone homeostasis under physiological and pathological conditions. To test our hypothesis, we will identify novel endocrine and paracrine circuits of osteoclast lineage cells by the system genetics bioinformatic framework QENIE (Aim 1) and experimentally validate and functionally assess these osteoclast-derived factors by in vitro cell culture and co-culture models (Aim 2). Successful accomplishment of the proposed work in this application will formulate new hypotheses to be tested using in vivo animal models and in human populations. The findings from this project will not only greatly advance our knowledge in osteoclast biology but also uncover new therapeutic targets to treat bone loss in bone and other organ diseases.