Pregnenolone Inhibits Osteoclast Differentiation and Protects Against Lipopolysaccharide-Induced Inflammatory Bone Destruction and Ovariectomy-Induced Bone Loss
Pregnenolone Inhibits Osteoclast Differentiation and Protects Against Lipopolysaccharide-Induced Inflammatory Bone Destruction and Ovariectomy-Induced Bone Loss
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孕烯醇酮抑制破骨细胞分化并防止脂多糖引起的炎性骨破坏和卵巢切除术引起的骨丢失
DOI：
10.3389/fphar.2020.00360
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发表时间：
2020-03-27
影响因子：
5.6
通讯作者：
Qin, An
中科院分区：
文献类型：
--
作者：
Sun, Xiaochen;Zhang, Chenxi;Qin, An
溶骨性骨病的特征是破骨细胞过度骨吸收，导致骨骼脆性增加和骨折风险上升。由单核前体细胞融合形成的多核破骨细胞是具有骨吸收能力的主要细胞。孕烯醇酮（Preg）是大多数（如果不是全部）类固醇激素的重要前体，并且被认为是一种新型的抗骨质疏松药物。然而，孕烯醇酮对破骨细胞生物学和功能的影响尚未得到证实。在此，我们在体外研究了孕烯醇酮对核因子κB受体活化因子配体（RANKL）诱导的破骨细胞形成和骨吸收的影响，以及在体内对炎症性骨破坏和骨质流失的潜在治疗应用。我们的体外细胞实验表明，孕烯醇酮能够以剂量依赖的方式抑制抗酒石酸酸性磷酸酶（TRAP）阳性破骨细胞的形成以及成熟破骨细胞的骨吸收。破骨细胞标记基因组织蛋白酶K（CTSK）、抗酒石酸酸性磷酸酶（TRAP）、树突状细胞特异性跨膜蛋白（DC - STAMP）、液泡型质子泵亚基d2（ATP6V0d2）和活化T细胞核因子c1（NFATc1）的表达显著减弱。对RANKL诱导的信号通路的生化分析表明，孕烯醇酮抑制细胞外调节蛋白激酶（ERK）丝裂原活化蛋白激酶（MAPK）和核因子 - κB的早期活化，从而削弱了下游c - Fos和NFATc1的诱导。通过活性氧（ROS）检测实验，我们发现孕烯醇酮在RANKL刺激后表现出抗氧化特性，抑制细胞内活性氧的产生。与这些体外结果一致，我们证实孕烯醇酮在体内通过抑制破骨细胞形成来保护小鼠免受局部脂多糖（LPS）诱导的炎症性骨破坏。此外，我们在体外未发现孕烯醇酮对成骨细胞生成和矿化有任何可观察到的影响。最后，将孕烯醇酮用于卵巢切除（OVX）诱导的骨质流失实验，结果表明孕烯醇酮可预防全身性卵巢切除诱导的骨质疏松症。总之，我们的观察结果为孕烯醇酮作为抗破骨细胞生成和抗吸收药物用于溶骨性骨病的潜在治疗提供了有力证据。
Osteolytic bone disease is characterized by excessive osteoclast bone resorption leading to increased skeletal fragility and fracture risk. Multinucleated osteoclasts formed through the fusion of mononuclear precursors are the principle cell capable of bone resorption. Pregnenolone (Preg) is the grand precursor of most if not all steroid hormones and have been suggested to be a novel anti-osteoporotic agent. However, the effects of Preg on osteoclast biology and function has yet to be shown. Here we examined the effect of Preg on receptor activator of nuclear factor kappa B ligand (RANKL)-induced osteoclast formation and bone resorption in vitro, and potential therapeutic application in inflammatory bone destruction and bone loss in vivo. Our in vitro cellular assays demonstrated that Preg can inhibit the formation of TRAP+ve osteoclast formation as well as mature osteoclast bone resorption in a dose-dependent manner. The expression of osteoclast marker genes CTSK, TRAP, DC-STAMP, ATP6V0d2, and NFATc1 were markedly attenuated. Biochemical analyses of RANKL-induced signaling pathways showed that Preg inhibited the early activation of extracellular regulated protein kinases (ERK) mitogen-activated protein kinase (MAPK) and nuclear factor-κB, which consequently impaired the downstream induction of c-Fos and NFATc1. Using reactive oxygen species (ROS) detection assays, we found that Preg exhibits anti-oxidant properties inhibiting the generation of intracellular ROS following RANKL stimulation. Consistent with these in vitro results, we confirmed that Preg protected mice against local Lipopolysaccharide (LPS)-induced inflammatory bone destruction in vivo by suppressing osteoclast formation. Furthermore, we did not find any observable effect of Preg on osteoblastogenesis and mineralization in vitro. Finally Preg was administered to ovariectomy (OVX)-induced bone loss and demonstrated that Preg prevented systemic OVX-induced osteoporosis. Collectively, our observations provide strong evidence for the use of Preg as anti-osteoclastogenic and anti-resorptive agent for the potential treatment of osteolytic bone conditions.