Osteoclast programming and reprogramming during osteoclastogenesis

摘要 破骨细胞是主要负责骨吸收的大型骨髓源性多核细胞。 破骨细胞分化的失调可导致净骨吸收，并且是骨质疏松症的病理生理学的关键。 骨质疏松症、类风湿性关节炎和溶解性骨转移。尽管在识别方面取得了实质性进展 破骨细胞主调节因子，发展病理性破骨细胞的治疗干预， 由于脱靶/副作用而具有挑战性。因此，我们假设更好地了解破骨细胞- 特异性调节可以直接导致新的破骨细胞特异性治疗策略的发展， 阻止或阻止疾病的发展。破骨细胞基因转录是高度组织化的， 由增强剂驱动。为了确定破骨细胞特异性表观遗传程序，我们专注于超- 增强剂。超级增强子是已经提出的调节免疫调节的关键基因的增强子簇。 细胞的身份和命运我们通过全基因组分析在人类破骨细胞中发现了348个超级增强子 不同的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。为了增加瞄准的可行性， 通过这些超级增强子，我们鉴定了一类新的从超级增强子转录的非编码RNA。 （命名为Oslincs）在人类破骨细胞中的作用，并提供证据表明Oslincs在基因表达中的作用 和破骨细胞生成。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起源。我们的具体目标是：1）确定 2）阐明Oslincs表达的机制， 调节，和3）鉴定在健康对照和患有糖尿病的患者之间差异调节的Oslincs 类风湿性关节炎（RA）。我们预计，这一提议产生的新信息将阐明 破骨细胞特异性调节，使我们能够探索实施新的，有针对性的治疗 改善病理性骨丢失过程的方法。

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.