Osteoclast programming and reprogramming during osteoclastogenesis

摘要 破骨细胞是大的、髓系来源的多核细胞，主要负责骨吸收。 破骨细胞分化失调可导致净骨吸收，是骨质疏松症病理生理学的关键。 骨质疏松、类风湿性关节炎和溶骨性骨转移。尽管在身份识别方面取得了实质性的进展 在破骨细胞主控调节剂的作用下，开发病理性破骨细胞的治疗干预措施 由于偏离目标/副作用而具有挑战性。因此，我们假设，对破骨细胞有更好的了解- 特定的调节可以直接导致新的破骨细胞特异性治疗策略的发展 防止或阻止疾病的发展。破骨细胞基因转录是高度有组织的，并被理解 由增强剂推动。为了确定破骨细胞特异性的表观遗传学程序，我们重点研究了超- 增强剂。超级增强子是一组增强子，已被提出用来调节 细胞身份和命运。通过全基因组分析，我们在人类破骨细胞中发现了348个超级增强子 差异转录和表观遗传调控。我们还发现RANKL调节的超级增强子 是破骨细胞特有的，但不存在于其他类型的细胞中。增加定向的可行性 这些超级增强子，我们鉴定了一类从超级增强子转录的新的非编码RNA (命名为Oslincs)在人类破骨细胞中表达，并提供了证据表明Oslincs在基因表达中的作用 和破骨细胞的形成。在本申请中，我们的目标是通过以下方式来表征破骨细胞特异性程序 研究Oslincs在健康和疾病中的作用和生物发生。我们的具体目标是1)确定 Oslincs功能的潜在机制，2)阐明Oslincs表达的机制 受调控，以及3)确定在健康对照组和糖尿病患者之间存在差异调控的Oslinc 类风湿关节炎(RA)。我们预计，这项提案产生的新信息将阐明 破骨细胞的特异性调控，使我们能够探索实施新颖的、有针对性的治疗方法 改善病理性骨丢失病程的途径。

Abstract Osteoclasts are large, myeloid-derived multinucleated cells primarily responsible for bone resorption. Dysregulation of osteoclast differentiation can result in net bone resorption and is key to the pathophysiology of osteoporosis, rheumatoid arthritis, and lytic bone metastasis. Despite substantial advances in the identification of osteoclast master regulators, developing therapeutic interventions for pathologic osteoclasts has been challenging due to off-target/side effects. Thus, we hypothesized that a better understanding of osteoclast- specific regulation can directly lead to the development of novel osteoclast-specific therapeutic strategies to prevent or halt the disease’s progression. Osteoclast gene transcription is highly organized and is understood to be driven by enhancers. In order to identify osteoclast-specific epigenetic programs, we focused on super- enhancers. Super-enhancers are clusters of enhancers that have been proposed to regulate key genes of cellular identity and fate. We found 348 super-enhancers in human osteoclasts through genome-wide analysis of differential transcriptional and epigenetic regulation. We also found that RANKL-regulated super-enhancers are specific to osteoclasts but do not present in other types of cells. To increase the feasibility of targeting these super-enhancers, we identified a new class of non-coding RNAs transcribed from super-enhancers (named Oslincs) in human osteoclasts and provided evidence showing the role of Oslincs in gene expression and osteoclastogenesis. In this application, we aim to characterize osteoclast-specific programs by investigating Oslincs’ action and biogenesis in health and disease. Our specific aims are to 1) determine the underlying mechanism of Oslincs’ function, 2) elucidate the mechanisms by which the expression of Oslincs is regulated, and 3) identify Oslincs that are differentially regulated between healthy controls and patients with rheumatoid arthritis (RA). We anticipate that the new information generated by this proposal will illuminate osteoclast-specific regulation and allow us to explore the implementation of novel, targeted therapeutic approaches for ameliorating the course of pathological bone loss.