白芦藜醇对牙周炎大鼠OPG/RANKL/RANK信号通路的影响

目的 考察白芦藜醇(Resveratrol, RSV)对牙周炎大鼠骨保护素(osteoprotegerin, OPG)/核因子-κB受体活化因子配体(receptor activator of NF-κB ligand, RANKL)/核因子-κB受体活化因子(receptor activator of NF-κB,RANK)(OPG/RANKL/RANK)信号通路相关蛋白的影响。方法 采用不同浓度的RSV对牙周炎大鼠进行干预，采用RT-PCR和Western blot分别检测牙周组织细胞OPG、RANKL、IL-1、IL-6、TNF-α和基质金属蛋白酶8(matrix metalloproteinase 8,MMP-8)的mRNA水平和蛋白表达水平。结果 牙周炎模型组大鼠牙周组织中OPG、RANKL、IL-1、IL-6、TNF-α和MMP-8的mRNA表达强度和蛋白水平高于空白对照组(P<0.05),RSV低剂量组、RSV中剂量组、RSV高剂量组则依次低于牙周炎模型组(P<0.05)。结论 RSV可以降低牙周炎大鼠牙周组织中OPG、RANKL、IL-1、IL-6、TNF-...     

骨碎补总黄酮对骨质疏松模型大鼠OPG/RANKL/RANK轴系统的影响

目的 研究不同剂量骨碎补总黄酮灌胃对骨质疏松模型大鼠雌激素水平及骨保护素(orthopantomography,OPG)、核因子κB受体活化因子(receptor activator of NF-κB,RANK)和核因子κB受体活化因子配体(receptor activator of NF-κB ligand,RANKL)表达的影响,探讨其对骨代谢影响的可能机制。方法 通过去卵巢法造成骨质疏松大鼠模型,以戊酸雌二醇片0.1 mg·kg^-1及低、中、高不同剂量骨碎补总黄酮(0.054,0.108,0.216 g·kg^-1·d^-1)喂养3个月后,取动脉血,采用放射免疫法测定雌激素水平,用酶联免疫吸附法(ELISA)检测破骨细胞OPG、RANK和RANKL的表达。结果 与模型组2相比,各给药组雌二醇及OPG的表达量增加(P<0.05),RANK和RANKL的表达量减少(P<0.05),且随着骨碎补总黄酮剂量的增加,雌二醇及OPG表达呈上升趋势,RANK和RANKL表达均呈下降趋势。结论 不同剂量骨碎补总黄酮均影响OPG/RANKL/RANK轴系统,且随骨碎补总黄酮剂量的增加效果越明显,可能是通过调控OPG/RANKL/RANK轴系统使OPG表达增加、RANK和RANKL的表达下降来实现的。     

中医药介导OPG/RANK/RANKL信号通路防治类风湿关节炎的研究进展

类风湿关节炎（rheumatoid arthritis, RA）是一种临床常见的以滑膜炎为主的自身免疫性疾病。炎性细胞因子和破骨细胞刺激滑膜组织增生、炎症反应、骨质破坏及关节功能障碍等，在RA的致病因素中占据关键位置。本文对中药单体及其提取物、中药复方及制剂、中药配伍，以及中医治疗通过调控骨保护蛋白（osteoprotegerin,OPG）/NF-κB受体激活因子（receptor activator of NF-κB, RANK）/NF-κB配体激活因子（receptor activator of NF-κB ligand, RANKL）信号通路干预RA的相关研究进行综述。结果表明，中药中的有效分子机制不同，但是可以起到调控信号通路的作用，刺激成骨细胞活性，抑制炎性细胞因子分泌，减少破骨细胞分化，从而防治RA，为中医药多靶点、多途径治疗RA提供理论依据。     

金雀异黄酮酊对去卵巢骨质疏松大鼠OPG/RANKL/RANK通路的影响

目的观察金雀异黄酮酊对去卵巢骨质疏松大鼠骨密度、血清骨代谢生物标志物以及骨保护素(osteoprotegerin,OPG)、核因子κB受体活化因子(receptor activator of NF-κB,RANK)和破骨细胞分化因子(receptor activator of NF-κB,RANKL)表达的影响,探讨其抗骨质疏松的作用机制。方法将30只3月龄SD雌性大鼠随机分为假手术组、模型组和金雀异黄酮酊组,通过去卵巢法构建骨质疏松大鼠模型,给予金雀异黄酮酊外用喷涂,治疗8周后分别测定大鼠股骨骨密度,采用Elisa法检测血清骨碱性磷酸酶(ALP)、骨钙素(OC)及血清Ⅰ型胶原交联C-末端肽(S-CTX)等骨代谢生物标志物,采用Western Blot法检测OPG和RANKL蛋白表达水平。结果与假手术组比较,去卵巢组大鼠子宫质量、血清雌激素水平、股骨骨密度、血钙、血磷和OPG蛋白表达水平均降低,而体质量、ALP、OC、S-CTX和RANKL蛋白表达水平均升高,差异有统计学意义(P<0.05);采用金雀异黄酮酊治疗8周后,与模型组比较,金雀异黄酮酊组体质量、ALP、OC、S-CTX和RANKL蛋白表达水平降低,而子宫质量、血清雌激素水平、股骨骨密度、血钙、血磷和OPG蛋白表达水平均升高,差异有统计学意义(P<0.05)。结论金雀异黄酮酊可调节骨代谢,显著提高骨质疏松大鼠的骨密度,可能与调控OPG/RANKL/RANK通路蛋白表达水平有关。     

探讨IL-17基于RANKL/RANK/OPG通路对类风湿关节炎骨破坏的作用机制

类风湿关节炎(RA)是一种以进行性关节破坏为特征的慢性自身免疫性疾病,病理改变主要以关节软骨及骨破坏为主,其发病机制与诸多细胞因子有着密切的关系,治疗不及时常常导致患者致畸致残。破骨细胞(OCs)在RA骨破坏的病理过程中起关键作用,其调控依赖于OCs形成、分化及活化的过程。白细胞介素-17(IL-17)是由辅助性T细胞17(Th17)产生的多效性细胞因子,相关研究发现它可以调节核因子-κB受体活化因子配体(RANKL)/核因子κB受体活化因子(RANK)/骨保护素(OPG)信号通路促进OCs的成熟及分化,引起骨质破坏。本文通过检索相关文献探讨IL-17通过RANKL/RANK/OPG信号通路在RA骨破坏机制中的作用,为早期RA的治疗提供新的靶点。     

吴茱萸次碱抗骨质疏松作用研究

骨保护素(osteoprotegerin,OPG)是骨转换的标志物,由成骨细胞等分泌.OPG与核因子-κB受体活化因子配体(receptor activator of nuclear factor-κB ligand,RANKL)结合发挥抑制破骨细胞作用.本研究发现吴茱萸次碱(rutaecarpine,RUT)具有上调...     

RANK-RANKL-OPG系统及其治疗骨质疏松相关药物的研究进展

骨骼是一种动态组织，由大约70%的矿物质和30%的有机成分组成，并通过持续的骨形成和骨吸收来维持。骨形成和骨吸收障碍可导致代谢性骨病，如骨坏死和骨质疏松症等。相关研究结果表明，骨保护素（osteoprotegerin，OPG）、核因子κB受体活化因子（receptor activator of nuclear factor-κB，RANK）及其配体（RANK ligand，RANKL）相关细胞因子参与或调节这一动态平衡。此文就RANK-RANKL-OPG系统及其治疗骨质疏松相关药物的研究进展作一综述。     

破骨细胞分化因子及其相关因子在慢性化脓性中耳炎肉芽组织中的表达

目的 探讨破骨细胞核因子кB受体活化因子配体(Receptor activator of nuclear factor-kap-pa B ligand,RANKL,又称破骨细胞分化因子)和其配体核因子-κB受体活化因子(Receptor acti-vator of nuclear factor-kappa B,RANK...     

柚皮素对破骨细胞特异性基因及OPG/RANKL/RANK表达的影响

目的 观察柚皮素对破骨细胞特异性基因组织蛋白酶-K(CATK)、基质金属蛋白酶-9(MMP-9)、抗酒石酸酸性磷酸酶(TRAP)及骨保护素/核因子-κB受体活化因子配体/核因子-κB受体活化因子(OPG/RANKL/RANK)表达的影响.方法 采用全骨髓细胞诱导法培养破骨细胞,细胞分5组:空白对照组、HG-DMEM诱导组、HG-DMEM+0构.1μmol/L柚皮素组、HG-DMEM+1μmol/L柚皮素组、HG-DMEM+10μmol/L柚皮素组.HE染色、TRAP染色观察破骨细胞形态;分光光度计检测TRAP阳性细胞数;Real time-PCR和Western-blot检测CATK、MMP-9、TRAP及OPG/RANKL/RANK mRNA和蛋白表达.结果 与空白对照组比较,HG-DMEM诱导组TRAP阳性细胞数、TRAP、MMP-9、CATK、RANKL、RANK mRNA和蛋白表达明显增加,OPG mRNA和蛋白表达明显降低(P<0.05).与HG-DMEM诱导组比较,柚皮素预处理24 h能够明显降低TRAP阳性细胞数、CATK、MMP-9、TRAP、RANKL、RANK mRNA和蛋白表达,增加OPG mRNA和蛋白表达(P<0.05),呈剂量依赖性.结论 柚皮素能够抑制破骨细胞的生成和分化,该作用可能是通过OPG/RANKL/RANK信号通路抑制TRAP、MMP-9、CATK表达实现的.     

丹参酮ⅡA调节骨关节炎小鼠骨代谢的作用机制

目的 探讨丹参酮ⅡA(TanⅡA)通过介导Yes激酶相关蛋白（Yes-associated protein,YAP）、核因子-κB受体活化因子配基（receptor activator of nuclear factor-κB ligand,RANKL）/核因子κB受体活化因子（eceptor activator of nuclear factor-κB,RANK）/骨保护蛋白（osteoprotegerin,OPG）调节骨关节炎小鼠骨代谢的作用机制。方法 建立骨关节炎小鼠模型,将60只小鼠随机分成假手术组、模型组、TanⅡA低剂量组和TanⅡA高剂量组,每组15只,造模成功后灌胃给药,连续4周。HE和番红O固绿染色观察软骨组织病理损伤并进行Mankin评分。酶联免疫吸附试验（enzyme-linked immunosorbent assay, ELISA）检测血清骨碱性磷酸酶（bone alkaline phosphatase,BALP）、骨钙素（osteocalcin,OC）、Ⅰ型胶原交联羧基末端肽（C-telopeptide of typeⅠcollagen,CTX）、白细胞介素...     

RANKL inhibition for the management of patients with benign metabolic bone disorders

The receptor activator of NF-κB ligand (RANKL) is a member of the TNF receptor superfamily, essential for osteoclastogenesis. It binds to its receptor activator of NF-κB on the surface of osteoclast precursors and enhances their differentiation, survival and fusion, while it activates mature osteoclasts and inhibits their apoptosis. The effects of RANKL are counteracted by osteoprotegerin (OPG), a neutralizing decoy receptor. Derangement of the balance in RANKL/OPG action is implicated in the pathophysiology of metabolic bone diseases, including osteoporosis. Current therapies used to prevent or treat metabolic bone diseases are thought to act, at least in part, through modification of the RANKL/OPG dipole. The idea of using a molecule that could specifically bind and neutralize RANKL to decrease bone resorption and subsequent bone loss is appealing. Recombinant OPG was initially tested. Denosumab, a fully human monoclonal antibody against RANKL, is a promising antiresorptive agent under investigation. It rapidly decreases bone turnover markers resulting in a significant increase in bone mineral density and reduction in fracture risk. However, because receptor activator of NF-κB activation by RANKL is also essential for T-cell growth and dendritic-cell function, inhibition of its action could simultaneously affect the immune system, leading to susceptibility in infections or malignancies.     

RANKL/RANK/OPG: key therapeutic target in bone oncology

Cancer is one of the major leading causes of death all over the world. Primary and secondary bone tumors can significantly deteriorate the quality of life (QOL) and the activity of daily living (ADL) of the patients. These unwelcome diseases become a social and economic burden seriously. Thus, more effective therapies for both primary and secondary bone tumors are actually required. Bone homeostasis depends on the strictly balanced activities between bone formation by osteoblasts and bone resorption by osteoclasts. Imbalance of bone formation and resorption results in various bone diseases. Both primary and secondary bone tumors develop in the unique environment bone, it is therefore necessary to understand bone cell biology in tumoral bone environment. Recent findings strongly revealed the significant involvement of the receptor activator of nuclear factor kappaB ligand (RANKL)/RANK/osteoprotegerin (OPG) triad, the key regulators of bone remodeling in bone oncology. Indeed, RANKL/RANK blocking successfully prevented the development of bone metastases. Furthermore, some cancer cells express RANK which is involved in tumor cell migration. Thus, the regulation of this triad will be a rational, encouraged therapeutic hot spot in bone oncology. In this review, we summarize the accumulating knowledge of the RANKL/RANK/OPG triad and discuss about its therapeutic capability in primary and secondary bone tumors.     

Olmesartan decreases IL-1β and TNF-α levels; downregulates MMP-2, MMP-9, COX-2, and RANKL; and upregulates OPG in experimental periodontitis

The objective of this study is to investigate the participation of inflammatory and oxidative stress mediators and the effects on the expression of matrix metalloproteinase (MMP)-2, MMP-9, and receptor activator of NF-κB ligand (RANKL)/receptor activator of NF-κB (RANK)/osteoprotegerin (OPG) pathway in the response to treatment with olmesartan, an angiotensin II type 1 receptor blocker. Male Wistar albino rats were randomly divided into five groups of ten rats each: (1) non-ligature with water, (2) ligature with water, (3) ligature with 1 mg/kg olmesartan, (4) ligature with 6 mg/kg olmesartan, and (5) ligature with 10 mg/kg olmesartan. All groups were treated with olmesartan or the vehicle by gavage daily for 10 days. Following the treatment course, the periodontal tissue of the animals was analyzed by histopathology and immunohistochemistry to determine the expression of cyclooxygenase-2 (COX-2), MMP-2, MMP-9, and members of the RANKL/RANK/OPG pathway and by ELISA and spectroscopic assay to determine the levels of interleukin (IL)-1β, IL-10, tumor necrosis factor (TNF)-α, myeloperoxidase (MPO), malonaldehyde (MDA), and glutathione. The concentrations of MPO and MDA were reduced in the group that received 6 mg/kg olmesartan (p?<?0.05). In addition, the group that was treated with 6 mg/kg olmesartan showed a decreased level of IL-1β (p?<?0.05), and all doses of olmesartan resulted in decreased levels of TNF-α. Furthermore, treatment with 6 mg/kg olmesartan led to downregulation of the expression of COX-2, MMP-2, MMP-9, RANKL, and RANK and to upregulation of the expression of OPG. These findings suggest that 6 mg/kg olmesartan reduces the inflammatory process and bone loss by downregulating MMPs and RANKL in osteoblasts and by upregulating OPG.     

Cell-based assay strategy for identification of motif-specific RANK signaling pathway inhibitors

Osteoclasts, the principal bone-resorbing cells, not only play a pivotal role in skeletal development and maintenance but are also implicated in the pathogenesis of various bone disorders such as postmenopausal osteoporosis, bone erosion in inflammatory conditions, and tumor-induced osteolysis. As a result, several antiresorptive drugs (agents capable of inhibiting osteoclast formation and/or function) have been developed and are widely used to prevent and treat these bone diseases. However, current antiresorptive agents either lack satisfactory efficacy or cause serious side effects in clinical management of these bone disorders. Almost a decade ago, the receptor activator of nuclear factor-kappaB (RANK) ligand (RANKL) was identified as an essential factor required for osteoclast formation. RANKL exerts the effect by binding to its receptor RANK on osteoclast precursors. RANKL also has a decoy receptor, osteoprotegerin (OPG), which inhibits RANKL function by competing with RANK for RANKL. The unraveling of the critical role for the RANKL/RANK/OPG system in osteoclast biology provides an unprecedented opportunity to develop more effective antiresorptive drugs. Unfortunately, the agents currently under development, such as OPG, RANK-Fc, and anti-RANKL antibodies, all inherit a serious drawback--lack of specificity, due to the involvement of the RANKL/RANK/OPG system in other biological processes such as immune response and mammary gland development. Thus, future efforts may need to shift to explore RANK signaling pathways as more effective therapeutic targets. Here, we review our current understanding of RANK signaling in osteoclasts and then discuss the potential of RANK signaling pathways as therapeutic pathways. Moreover, we further describe a strategy for constructing novel cell-based systems for identifying compounds inhibiting signaling from two recently identified RANK motifs through high throughput screening. We hope that this review will not only provide readers with an update on progress in this area of research but, more importantly, will also serve as a starting point for further discussion and eventual development of new strategies for harnessing the ultimate potential of the RANKL/RANK/OPG system as antiresorptive therapeutic targets.     

Osteoprotegerin: a physiological and pharmacological inhibitor of bone resorption

OPG is a new member of the tumor necrosis factor (TNF) receptor family which plays a key role in the physiological regulation of osteoclastic bone resorption. The protein, which is produced by osteoblasts and marrow stromal cells, lacks a transmembrane domain and acts as a secreted decoy receptor which has no direct signaling capacity. OPG acts by binding to its natural ligand OPGL, which is also known as RANKL (receptor activator of NF-kappaB ligand). This binding prevents OPGL from activating its cognate receptor RANK, which is the osteoclast receptor vital for osteoclast differentiation, activation and survival. Overexpression of OPG in transgenic mice leads to profound osteopetrosis secondary to a near total lack of osteoclasts. Conversely, ablation of the OPG gene causes severe osteoporosis in mice. Ablation of OPGL or RANK also produces profound osteopetrosis, indicating the important physiological role of these proteins in regulating bone resorption. The secretion of OPG and OPGL from osteoblasts and stromal cells is regulated by numerous hormones and cytokines, often in a reciprocal manner. The relative levels of OPG and OPGL production are thought to ultimately dictate the extent of bone resorption. Excess OPGL increases bone resorption, whereas excess OPG inhibits resorption. Recombinant OPG blocks the effects of virtually all factors which stimulate osteoclasts, in vitro and in vivo. OPG also inhibits bone resorption in a variety of animal disease models, including ovariectomy-induced osteoporosis, humoral hypercalcemia of malignancy, and experimental bone metastasis. OPG might represent an effective therapeutic option for diseases associated with excessive osteoclast activity.     

Protective effect of zinc supplementation against cadmium-induced oxidative stress and the RANK/RANKL/OPG system imbalance in the bone tissue of rats

It was investigated whether protective influence of zinc (Zn) against cadmium (Cd)-induced disorders in bone metabolism may be related to its antioxidative properties and impact on the receptor activator of nuclear factor (NF)-κΒ (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) system. Numerous indices of oxidative/antioxidative status, and Cd and Zn were determined in the distal femur of the rats administered Zn (30 and 60 mg/l) or/and Cd (5 and 50 mg/l) for 6 months. Soluble RANKL (sRANKL) and OPG were measured in the bone and serum. Zn supplementation importantly protected from Cd-induced oxidative stress preventing protein, DNA, and lipid oxidation in the bone. Moreover, Zn protected from the Cd-induced increase in sRANKL concentration and the sRANKL/OPG ratio, and decrease in OPG concentration in the bone and serum. Numerous correlations were noted between indices of the oxidative/antioxidative bone status, concentrations of sRANKL and OPG in the bone and serum, as well as the bone concentrations of Zn and Cd, and previously reported by us in these animals (Brzóska et al., 2007) indices of bone turnover and bone mineral density. The results allow us to conclude that the ability of Zn to prevent from oxidative stress and the RANK/RANKL/OPG system imbalance may be implicated in the mechanisms of its protective impact against Cd-induced bone damage. This paper is the first report from an in vivo study providing evidence that beneficial Zn impact on the skeleton under exposure to Cd is related to the improvement of the bone tissue oxidative/antioxidative status and mediating the RANK/RANKL/OPG system.     

In vitro effects of erythromycin on RANKL and nuclear factor-kappa B by human TNF-α stimulated Jurkat cells

The receptor activator of NF-κB ligand (RANKL) and its signal downstream nuclear factor-κB (NF-κB) are critical regulators for immune responses as well as bone remodeling. The present study aimed to examine the effects of erythromycin (EM) on the activation of RANKL, correlation with NF-κB expression, proliferation and apoptosis of human Jurkat T cells. Jurkat T cells were pretreated with 100 pmol/l tumor necrosis factor-alpha (TNF-α) for 1 h followed by various concentrations of EM for 24 h. The mRNA expressions of RANKL and NF-κB were examined by RT-PCR. The protein expression of NF-κB was analyzed by Western blot. The protein level of RANKL was examined by flow cytometry, immunofluorescence microscopy and Western blot analyses. We also examined proliferation of Jurkat T cells by MTT assay, apoptosis by flow cytometry analysis after staining with PI and morphological observation after AO/EB staining. The results showed that EM inhibited TNF-α-induced expressions of RANKL and NF-κB at both mRNA and protein levels in a concentration-dependent manner. The expression of RANKL was correlated with the expression of NF-κB. Moreover, EM influenced the proliferation and apoptosis of human Jurkat T cells. These data suggest that EM acts as an anti-inflammatory agent not only to interact with the expression of NF-κB and the proliferation of human Jurkat T cells, but also to reduce the level of RANKL.     

PEGylation of an osteoclast inhibitory peptide: suitable candidate for the treatment of osteoporosis

Osteoporosis is a condition of bone loss due to excessive osteoclastic activity. Several protein factors, such as receptor activator of nuclear factor kappa-B (RANK), receptor activator of nuclear factor kappa-B ligand (RANKL), osteoprotegerin (OPG), have been identified that are important in the pathogenesis of osteoporosis. RANKL binds to RANK and activates the NF-κB pathway by interaction of its cytoplasmic domain with an intracellular adapter protein, TNF receptor associated factors 6 (TRAF 6). This interaction can be inhibited by cell-permeable peptides that prevent RANK-TRAF 6 interaction. However, similar to the peptides/proteins used in clinical setting, the effective application of this TRAF 6 Inhibitory peptide as a therapeutic agent is marred by several limitations for instance short half-life, rapid renal clearance and immunogenicity. In the present study, we have developed PEGylated TRAF 6 Inhibitory peptide by conjugating TRAF 6 Inhibitory peptide to linear PEG backbone that exhibits longer bioavailability in plasma in the animal model. Besides, it has an enhanced uptake at its site of action, i.e., bone marrow.     

Osteoprotegerin and RANKL regulate bone resorption, density, geometry and strength

Osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANKL) are dominant regulators of bone resorption. Many hormones, cytokines and growth factors mediate bone resorption by altering the ratio of RANKL to OPG. RANKL and OPG expression is also altered in numerous bone diseases, and these changes can reflect disease etiology or compensatory responses to disease. RANKL stimulates osteoclast formation, function and survival, and each of these effects is inhibited by OPG. OPG suppresses bone resorption and increases the density, area and strength of both cancellous and cortical bone. Denosumab (AMG 162), a fully human monoclonal antibody to RANKL, shares the pharmacologic attributes of OPG but has a significantly longer half-life that allows less frequent administration.