BACKGROUND & AIMS: :The effect of prostaglandin E1 (PGE1) on osmotic water flow across toad bladder and cyclic AMP content of the mucosal epithelial cells has been determined under basal conditions and in the presence of either theophylline or antidiuretic hormone (ADH); Under basal conditions and with PGE1 concentrations from 10(-8) to 10(-5) M no evidence of stimulation of water flow was observed, and with 10(-7) M PGE1 a significant inhibition was foundmcyclic AMP content under control conditions was 8 pmol/mg protein. It was 9 at 10(-8) M PGE1, 13 at 10(-7) M, 16 at 10(-6) M, and 23 at 10(-5) M. In the presence of theophylline, 10(-8) and 10(-7) M PGE1 inhibited the theophylline-induced water flow as expected. In contrast, 10(-6) and 10(-5) M PGE1 enhanced the rate of water flow. Theophylline increased cyclic AMP content from 8 to 18 pmol/mg protein. PGE1 in the presence of theophylline caused marked increases in cyclic AMP content; The content was 23 at 10(-7) M, 41 at 10(-6) M, and 130 at 10(-5) M; Thus PGE1 stimulates theophylline-induced water flow at cyclic AMP concentrations somewhere between 23 and 41 pmol/mg. Further evidence along these lines was obtained from experiments in which the effects of PGE1 on ADH-induced water flow were studied. Inhibitory effects of PGE1 were not observed at concentrations of PGE1 which raised the level of intracellular cyclic AMP to 30 pmol/mg protein or higher. These results were obtained despite the fact that all four concentrations of PGE1 tested were found capable of inhibiting ADH-induced water flow under appropriate conditions or, in other words, were inhibiting the adenylate cyclase controlling water flow, Thus the increase in cyclic AMP content in response to PGE1 is not derived from this enzyme. Thus the stimulation of water flow by PGE1 in the presence of theophylline is thought to be caused by cyclic AMP spilling over from one compartment to the water flow compartment. No evidence was obtained to directly suggest spillover into the sodium transport compartment. Furthermore evidence is discussed to suggest that most of the cyclic AMP generated in the tissue does not originate from the enzyme controlling sodium transport. As cyclic AMP-stimulated water flow and sodium transport are thought to occur in one cell type, the granular cells, distinct pools of cyclic AMP are thought to be present in one and the same cell type. Thus one pool controls water flow and one controls sodium transport. With high concentrations of PGE1 in the presence of theophylline or high concentrations of ADH, the adenylate cyclase responsible for water flow is inhibited; However, PGE1 can stimulate a tissue adenylate cyclase to sufficiently high levels that cyclic AMP spills over into the "water flow compartment" and thus stimulates water flow.

背景与目标： : 在基础条件下以及茶碱或抗利尿激素 (ADH) 存在下，已经确定了前列腺素E1 (PGE1) 对穿过蟾蜍膀胱的渗透水流和粘膜上皮细胞的环状AMP含量的影响; 在基础条件下，PGE1浓度为10(-8) 至10(-5) M，未观察到水流刺激的迹象，而在10(-7) M PGE1的情况下，在对照条件下发现环AMP含量显着抑制为8 pmol/mg蛋白。在10(-8) M PGE1为9，在10(-7) M为13，在10(-6) M为16，在10(-5) M为23。在茶碱存在下，10(-8) 和10(-7) M PGE1如预期的那样抑制茶碱诱导的水流。相反，10(-6) 和10(-5) M PGE1增强了水流速率。茶碱将环状AMP含量从8 pmol/mg增加到18 pmol/mg蛋白。茶碱存在下的PGE1导致循环AMP含量显着增加; 在10(-7) M时含量为23，在10(-6) M时含量为41，在10(-5) M时含量为130; 因此，PGE1在23至41 pmol/mg之间的循环AMP浓度下刺激茶碱诱导的水流。从实验中获得了沿着这些路线的进一步证据，其中研究了PGE1对ADH诱导的水流的影响。在PGE1浓度下未观察到PGE1的抑制作用，后者将细胞内环AMP的水平提高到30 pmol/mg蛋白或更高。尽管发现所测试的所有四种浓度的PGE1都能够在适当的条件下抑制ADH诱导的水流，或者换句话说，抑制控制水流的腺苷酸环化酶，因此循环AMP含量的增加响应PGE1不是由该酶衍生的。因此，认为在茶碱存在下PGE1对水流的刺激是由循环AMP从一个隔室溢出到水流隔室引起的。没有证据表明直接溢出到钠运输室中。此外，还讨论了证据表明，组织中产生的大多数环状AMP并非来自控制钠转运的酶。由于认为循环AMP刺激的水流和钠转运发生在一种细胞类型中，因此颗粒细胞，不同的循环AMP池被认为存在于一种相同的细胞类型中。因此，一个水池控制水流，一个水池控制钠的运输。在茶碱或高浓度ADH存在下高浓度的PGE1时，负责水流的腺苷酸环化酶被抑制; 然而，PGE1可以刺激组织腺苷酸环化酶达到足够高的水平，从而使循环AMP溢出到 “水流隔室” 中，从而刺激水流。

BACKGROUND & AIMS: Background:Visceral adipose tissue-derived serine protease inhibitor (vaspin), an adipose-derived hormone, exhibits various biological functions. Recently, studies showed that vaspin is closely related to bone metabolism. However, how vaspin influences bone formation and its underlying mechanisms in high fat-induced obese rats and rat primary osteoblasts (OBs) are not fully understood. In this study, the effects of vaspin on bone mechanical parameters and microarchitecture were evaluated. Methods:A total of 40 male Sprague-Dawley (SD) rats at 5-week old were fed with high fat diet (HFD) and normal diet (ND) for 12 weeks followed by treatment of vaspin for 10 weeks. Micro CT and three-point bending tests were conducted to evaluate bone microstructure and biomechanics. The alkaline phosphatase (ALP) activity, expression of Runt-related transcription factor 2 (Runx2), Osterix (Osx), Collegen alpha1 (Colla1) procollagen I N-terminal peptide (PINP), C-telopeptide of type I collagen (CTX), Smad2/3 and p-Smad2/3 was detected by different methods. Results:Our data indicated that, compared with ND rats, HFD rats exhibited high body weight, decreased bone strength and deteriorative bone quality. In contrast, vaspin reduced the body weight, improved the whole body metabolic status, enhanced bone strength, trabecular bone mass, and expression of Runx2, Osx, PINP, and decreased the expression level of plasma CTX. In vitro studies showed that vaspin promoted osteogenic differentiation and ALP activity in rat primary OBs in a dose dependent manner. Vaspin also upregulated mRNA expression of osteogenesis-related genes Runx2, Osx and Colla1 and protein expression of Runx2, Smad2/3 and p-Smad2/3. Conclusions:Our results indicated that vaspin protects against HFD-induced bone loss, and promotes osteogenic differentiation by activating the Smad2/3-Runx2 signaling pathway.

背景与目标：

BACKGROUND & AIMS: :The effects of prostaglandin E1 on cell-mediated cytotoxicity against hepatocytes were investigated using an in vitro cytotoxic assay system. Isolated liver cells from normal C57BL/6 mice were used as the target cells, and effector cells were obtained from spleens of C57BL/6 mice in which experimental hepatitis had been induced by immunization with syngeneic liver antigens. In this assay system, spleen T cells adhering to nylon wool demonstrated a high cytotoxic activity against target liver cells. The cytotoxicity was markedly reduced by prostaglandin E1 at concentrations greater than 10(-7) M. Maximum suppressive activity was obtained when prostaglandin E1 was continuously present during the assay period. By contrast, indomethacin, a specific inhibitor of prostaglandin synthesis, enhanced the cytotoxic activity of effector cells. These data seem to indicate that exogenously added prostaglandin E1 has an inhibitory effect on cell-mediated cytotoxicity of effector spleen cells against target hepatocytes.

背景与目标： : 使用体外细胞毒性测定系统研究了前列腺素E1对细胞介导的对肝细胞的细胞毒性的影响。从正常C57BL/6小鼠分离的肝细胞用作靶细胞，并从C57BL/6小鼠的脾脏中获得效应细胞，其中通过用同基因肝抗原预防接种诱导了实验性肝炎。在此测定系统中，粘附在尼龙羊毛上的脾T细胞显示出对目标肝细胞的高细胞毒性活性。浓度大于10(-7) M的前列腺素E1显着降低了细胞毒性。当在测定期间连续存在前列腺素E1时，可获得最大的抑制活性。相比之下，吲哚美辛是前列腺素合成的特异性抑制剂，可增强效应细胞的细胞毒性活性。这些数据似乎表明，外源添加的前列腺素E1对效应脾细胞对靶肝细胞的细胞介导的细胞毒性具有抑制作用。

BACKGROUND & AIMS: :Glycation reactions resulting in the generation and accumulation of advanced glycation endproducts (AGEs) are potential mechanisms by which bone protein may be altered in vivo. AGEs accumulate in the bone increasingly with age come into close contact with osteoblasts or osteoclasts. The direct effect of AGEs on bone cells has not been thoroughly investigated. This study aimed to examine whether glycated bovine serum albumin (AGE - BSA) as an AGE modulate the mRNA expression of various genes in primary human osteoblast cultures. The following parameters were included: RAGE (receptor for AGEs), alkaline phosphatase, osteocalcin, osterix and RANKL (receptor activator of nuclear factor-kappaB ligand). Primary human osteoblast cultures were obtained from bone specimens of six patients with osteoarthrosis. Human osteoblasts were treated in AGE - BSA or control-BSA (non-glycated BSA) containing medium (5 mg/ml each) over a time course of seven days. After RT-PCR the mRNA expression was measured by real-time PCR. Related to control - BSA exposure, the mRNA expression of RAGE, RANKL and osterix increased during AGE - BSA treament. For alkaline phosphatase and osteocalcin a tendency of down-regulation was found. In summary, the study presents evidence that advanced glycation end products accumulated in bone alter osteoblasts by activation the AGE - RAGE pathway (RAGE mRNA up-regulation), inducing enhanced osteoclastogenesis (RANKL mRNA up-regulation) and impaired matrix mineralization (down-regulation of alkaline phosphatase and osteocalcin mRNA). Thus, AGEs may play a functional role in the development of bone diseases (e.g. osteoporosis).

背景与目标： : 糖基化反应导致高级糖基化终产物 (AGEs) 的产生和积累是体内改变骨蛋白的潜在机制。随着年龄的增长，年龄在骨中的积累越来越多地与成骨细胞或破骨细胞密切接触者。年龄对骨细胞的直接影响尚未得到彻底研究。这项研究旨在检查糖化牛血清白蛋白 (AGE - BSA) 是否作为年龄调节原代人成骨细胞培养物中各种基因的mRNA表达。包括以下参数: RAGE (AGEs受体)，碱性磷酸酶，骨钙素，osterix和RANKL (核因子-κ b配体的受体激活剂)。从6例骨关节炎患者的骨标本中获得了原代人成骨细胞培养物。在7天的时间过程中，在含有AGE-BSA或对照-BSA (非糖化BSA) 的培养基 (每个5 mg/ml) 中治疗人成骨细胞。Rt-pcr后，通过实时PCR测量mRNA表达。与对照-BSA暴露有关，RAGE，RANKL和osterix的mRNA表达在年龄-BSA治疗期间增加。对于碱性磷酸酶和骨钙素，发现有下调的趋势。总而言之，该研究提供了证据，表明在骨中积累的高级糖基化终产物通过激活AGE-RAGE途径 (RAGE mRNA上调)，诱导破骨细胞生成增强 (RANKL mRNA上调) 和基质矿化受损 (下调碱性磷酸酶和骨钙素mRNA) 来改变成骨细胞。因此，年龄可能在骨骼疾病 (例如骨质疏松症) 的发展中起功能作用。

BACKGROUND & AIMS: :G protein-coupled receptors (GPCRs) coupled to activation of Gs, such as the PTH1 receptor (PTH1R), have long been known to regulate skeletal function and homeostasis. However, the role of GPCRs coupled to other G proteins such as Gi is not well established. We used the tet-off system to regulate the expression of an activated Gi-coupled GPCR (Ro1) in osteoblasts in vivo. Skeletal phenotypes were assessed in mice expressing Ro1 from conception, from late stages of embryogenesis, and after weaning. Long bones were assessed histologically and by microcomputed tomography. Expression of Ro1 from conception resulted in neonatal lethality that was associated with reduced bone mineralization. Expression of Ro1 starting at late embryogenesis resulted in a severe trabecular bone deficit at 12 wk of age (>51% reduction in trabecular bone volume fraction in the proximal tibia compared with sex-matched control littermates; n = 11; P < 0.01). Ro1 expression for 8 wk beginning at 4 wk of age resulted in a more than 20% reduction in trabecular bone volume fraction compared with sex-matched control littermates (n = 16; P < 0.01). Bone histomorphometry revealed that Ro1 expression is associated with reduced rates of bone formation and mineral apposition without a significant change in osteoblast or osteoclast surface. Our results indicate that signaling by a Gi-coupled GPCR in osteoblasts leads to osteopenia resulting from a reduction in trabecular bone formation. The severity of the phenotype is related to the timing and duration of Ro1 expression during growth and development. The skeletal phenotype in Ro1 mice bears some similarity to that produced by knockout of Gs-alpha expression in osteoblasts and thus may be due at least in part to Gi-mediated inhibition of adenylyl cyclase.

背景与目标： : g蛋白偶联受体 (GPCRs) 与Gs的激活 (例如PTH1受体 (PTH1R)) 偶联，长期以来一直已知可以调节骨骼功能和体内平衡。但是，与其他g蛋白 (例如Gi) 偶联的GPCRs的作用尚不明确。我们使用tet-off系统调节体内成骨细胞中活化的Gi偶联GPCR (Ro1) 的表达。在受孕，胚胎发生后期和断奶后表达Ro1的小鼠中评估了骨骼表型。通过组织学和显微计算机断层扫描对长骨进行评估。受孕后Ro1的表达导致新生儿致死，这与骨矿化减少有关。在胚胎发生晚期开始的Ro1的表达导致在12周龄时严重的小梁骨缺损 (与性别匹配的同窝对照相比，胫骨近端的小梁骨体积分数> 51% 减少; n = 11; P <0.01)。与性别匹配的同窝对照组相比，从4周龄开始的8周Ro1表达导致小梁骨体积分数减少20% 以上 (n = 16; P <0.01)。骨组织形态计量学显示，Ro1表达与骨形成和矿物质并置率降低有关，而成骨细胞或破骨细胞表面没有明显变化。我们的结果表明，成骨细胞中Gi偶联GPCR的信号传导导致骨小梁骨形成减少导致骨质减少。表型的严重程度与生长发育过程中Ro1表达的时间和持续时间有关。Ro1小鼠的骨骼表型与成骨细胞中Gs-α 表达的敲除产生的表型相似，因此可能至少部分归因于Gi介导的腺苷酸环化酶的抑制。

BACKGROUND & AIMS: :Mechano-growth factor (MGF), a splice variant of insulin-like growth factor I (IGF-I), was discovered by Goldspink and colleagues in 1996; since then many studies have implicated MGF as an important local tissue repair factor. Although the short 24-amino-acid C-terminal peptide of MGF (MGF-Ct24E) has a variety of biological activities, its role in bone formation has not yet been clarified. Accordingly, the aim of this study was to investigate the role of MGF-Ct24E in the proliferation, differentiation, and mineralization of rat calvarial osteoblasts. Interestingly, although MGF-Ct24E significantly increased the proliferation and retarded the differentiation of osteoblasts during the first 3 days, prolonged treatment with MGF-Ct24E for up to 3 weeks promoted cell differentiation. To determine the molecular mechanisms behind this plurality, we carried out global transcriptional profiling of osteoblasts in response to MGF-Ct24E and identified differentially expressed genes by bioinformatics analysis. Gene ontology analysis indicated that MGF-Ct24E enhanced the expression of genes associated with osteoblast proliferation and the cell cycle and downregulated genes involved with osteoblast differentiation, skeletal system, and bone development. Moreover, KEGG pathway-based analysis indicated that MGF-Ct24E directly altered focal adhesion and cell cycle progression, in addition to regulating the actin cytoskeleton and gap junctions. In conclusion, MGF-Ct24E has a marked ability to increase bone formation by increasing cell proliferation and delaying cell differentiation during prophase, as well as by stimulating osteoblast differentiation during the advanced stage. The mechanism of action of MGF-Ct24E during the initial stages of bone formation in vitro involves upregulation of the expression of genes involved in proliferation and cell cycle progression, and the repression of differentiation-related genes.

背景与目标： : 机械生长因子 (MGF) 是胰岛素样生长因子I (igf-i) 的剪接变体，由Goldspink及其同事1996年发现; 此后，许多研究表明MGF是重要的局部组织修复因子。尽管MGF (MGF-Ct24E) 的短24氨基酸C端肽具有多种生物学活性，但其在骨形成中的作用尚未阐明。因此，本研究的目的是研究MGF-Ct24E在大鼠颅骨成骨细胞增殖，分化和矿化中的作用。有趣的是，尽管MGF-Ct24E在最初的3天中显着增加了成骨细胞的增殖并延迟了成骨细胞的分化，但延长MGF-Ct24E治疗长达3周可促进细胞分化。为了确定这一多个背后的分子机制，我们对成骨细胞进行了整体转录分析，以响应MGF-Ct24E，并通过生物信息学分析鉴定了差异表达的基因。基因本体分析表明，MGF-Ct24E增强了与成骨细胞增殖和细胞周期相关的基因的表达，并下调了与成骨细胞分化，骨骼系统和骨骼发育有关的基因的表达。此外，基于KEGG途径的分析表明，除了调节肌动蛋白细胞骨架和间隙连接外，MGF-Ct24E还直接改变了黏着斑和细胞周期进程。总之，MGF-Ct24E具有通过在前期增加细胞增殖和延迟细胞分化以及在晚期刺激成骨细胞分化来增加骨形成的显著能力。在体外骨形成的初始阶段，MGF-Ct24E的作用机制涉及参与增殖和细胞周期进程的基因表达的上调以及分化相关基因的抑制。

BACKGROUND & AIMS: :By pulse-chase labeling with [35S]methionine and long-term labeling with 3H-sugars, the E1 glycoprotein of coronavirus MHV-A59 has been shown to acquire O-linked oligosaccharides in a two-step process. About 10 min after synthesis of the E1 protein, N-acetyl-galactosamine was added. This was followed approximately 10 min later by the addition of both galactose and sialic acid to give the mature oligosaccharides. This sequence of additions was confirmed by analyzing the 3H-labeled oligosaccharides bound to each of the E1 forms using gel filtration on P4 columns. The intracellular location of the first step was determined by exploiting the temperature sensitivity of virus release. The virus normally buds first into a smooth membrane compartment lying between the rough endoplasmic reticulum and the cis side of the Golgi stack (Tooze et al., 1984). At 31 degrees C the virus is assembled but does not appear to enter the Golgi stacks. The addition of N-acetyl-galactosamine is unaffected although the addition of galactose and sialic acid is inhibited. These results strongly suggest that addition of N-acetyl-galactosamine occurs in this budding compartment, the morphology of which is similar to that of transitional elements and vesicles.

背景与目标： : 通过用 [35S] 蛋氨酸进行脉冲追踪标记和用3h-糖进行长期标记，已证明冠状病毒MHV-A59的E1糖蛋白可以通过两步过程获得O-连接的寡糖。合成E1蛋白后约10分钟，加入N-乙酰半乳糖胺。大约10分钟后，加入半乳糖和唾液酸，得到成熟的寡糖。通过在P4柱上使用凝胶过滤分析与每种E1形式结合的3h标记的寡糖，证实了这种加入顺序。第一步是通过利用病毒释放的温度敏感性来确定的。病毒通常首先发芽进入位于粗糙内质网和高尔基体顺式侧之间的光滑膜室 (Tooze等人，1984)。在31摄氏度下，病毒被组装，但似乎没有进入高尔基体。尽管半乳糖和唾液酸的添加被抑制，但N-乙酰基半乳糖胺的添加不受影响。这些结果强烈表明N-乙酰基半乳糖胺的添加发生在这个萌芽室中，其形态与过渡元素和囊泡相似。

BACKGROUND & AIMS: :Bone turnover in vivo is regulated by mechanical forces such as shear stress originating from interstitial oscillatory fluid flow (OFF), and bone cells in vitro respond to mechanical loading. However, the mechanisms by which bone cells sense mechanical forces, resulting in increased mineral deposition, are not well understood. The aim of this study was to investigate the role of the primary cilium in mechanosensing by osteoblasts. MLO-A5 murine osteoblasts were cultured in monolayer and subjected to two different OFF regimens: 5 short (2 h daily) bouts of OFF followed by morphological analysis of primary cilia; or exposure to chloral hydrate to damage or remove primary cilia and 2 short bouts (2 h on consecutive days) of OFF. Primary cilia were shorter and there were fewer cilia per cell after exposure to periods of OFF compared with static controls. Damage or removal of primary cilia inhibited OFF-induced PGE2 release into the medium and mineral deposition, assayed by Alizarin red staining. We conclude that primary cilia are important mediators of OFF-induced mineral deposition, which has relevance for the design of bone tissue engineering strategies and may inform clinical treatments of bone disorders causes by load-deficiency.

背景与目标： : 体内的骨转换受机械力 (例如来自间质振荡流体流动 (OFF) 的剪切应力) 调节，体外的骨细胞对机械负荷做出反应。然而，骨细胞感知机械力导致矿物质沉积增加的机制尚不清楚。这项研究的目的是研究初级纤毛在成骨细胞机械感应中的作用。将MLO-A5鼠成骨细胞单层培养，并进行两种不同的OFF方案: 5次短时间 (每天2小时) OFF，然后对初级纤毛进行形态学分析; 或暴露于水合氯醛以破坏或去除初级纤毛，并进行2次短时间OFF (连续2小时)。与静态对照相比，暴露于OFF期后的初级纤毛更短，每个细胞的纤毛更少。通过茜素红染色测定，初级纤毛的损伤或去除抑制了非诱导的PGE2释放到培养基和矿物质沉积中。我们得出的结论是，原发性纤毛是非诱导矿物质沉积的重要介质，这与骨组织工程策略的设计有关，并可能为临床治疗因负荷不足而引起的骨疾病提供信息。

BACKGROUND & AIMS: :The present study aimed to investigate the role of magnitude in adaptive response of osteoblasts exposed to compressive stress. Murine primary osteoblasts and MC3T3-E1 cells were exposed to compressive stress (0, 1, 2, 3, 4, and 5 g/cm2) in 3D culture. Cell viability was evaluated, and expression levels of Runx2, Alp, Ocn, Rankl, and Opg were examined. ALP activity in osteoblasts and TRAP activity in RAW264.7 cells co-cultured with MC3T3-E1 cells were assayed. Results showed that compressive stress within 5.0 g/cm2 did not influence cell viability. Both osteoblastic and osteoblast-regulated osteoclastic differentiation were enhanced at 2 g/cm2. An increase in stress above 2 g/cm2 did not enhance osteoblastic differentiation further but significantly inhibited osteoblast-regualted osteoclastic differentiation. This study suggested that compressive stress regulates osteoblastic and osteoclastic differentiation through osteoblasts in a magnitude-dependent manner.

背景与目标： : 本研究旨在研究强度在承受压应力的成骨细胞适应性反应中的作用。小鼠原代成骨细胞和MC3T3-E1细胞在3D培养中暴露于压缩应力 (0、1、2、3、4和5  g/cm2)。评估细胞活力，并检查Runx2，Alp，Ocn，Rankl和Opg的表达水平。测定了成骨细胞中的ALP活性和与MC3T3-E1细胞共培养的RAW264.7细胞中的TRAP活性。结果表明，5.0  g/cm2内的压应力不影响细胞活力。成骨细胞和成骨细胞调节的破骨细胞分化均以2  g/cm2增强。2  g/cm2以上的压力增加不会进一步增强成骨细胞的分化，但会显着抑制成骨细胞的破骨细胞分化。这项研究表明，压缩应力通过成骨细胞以幅度依赖的方式调节成骨细胞和破骨细胞的分化。

BACKGROUND & AIMS: :Osteocytes are the terminally differentiated cell type of the osteoblastic lineage and have important functions in skeletal homeostasis. Although the transcriptional regulation of osteoblast differentiation has been well characterized, the factors that regulate differentiation of osteocytes from mature osteoblasts are poorly understood. Here we show that miR-23a∼27a∼24-2 (miR-23a cluster) promotes osteocyte differentiation. Osteoblast-specific miR-23a cluster gain-of-function mice have low bone mass associated with decreased osteoblast but increased osteocyte numbers. By contrast, loss-of-function transgenic mice overexpressing microRNA decoys for either miR-23a or miR-27a, but not miR24-2, show decreased osteocyte numbers. Moreover, RNA-sequencing analysis shows altered transforming growth factor-β (TGF-β) signalling. Prdm16, a negative regulator of the TGF-β pathway, is directly repressed by miR-27a with concomitant alteration of sclerostin expression, and pharmacological inhibition of TGF-β rescues the phenotypes observed in the gain-of-function transgenic mice. Taken together, the miR-23a cluster regulates osteocyte differentiation by modulating the TGF-β signalling pathway through targeting of Prdm16.

背景与目标： : 骨细胞是成骨细胞谱系的终末分化细胞类型，在骨骼稳态中具有重要功能。尽管成骨细胞分化的转录调控已得到很好的表征，但对调节骨细胞从成熟成骨细胞分化的因素知之甚少。在这里，我们显示miR-23a〜27a〜24-2 (miR-23a簇) 促进骨细胞分化。成骨细胞特异性miR-23a簇功能获得小鼠的骨量低，与成骨细胞数量减少有关，但骨细胞数量增加。相比之下，过表达miR-23a或miR-27a但不是miR24-2的microRNA诱饵的功能丧失转基因小鼠显示骨细胞数量减少。此外，RNA测序分析显示了转化生长因子-β (TGF-β) 信号的改变。Prdm16是TGF-β 途径的负调节剂，被miR-27a直接抑制，伴随着硬化蛋白表达的改变，TGF-β 的药理抑制挽救了在功能获得的转基因小鼠中观察到的表型。综合起来，miR-23a簇通过靶向prdm16调节TGF-β 信号通路来调节骨细胞分化。

BACKGROUND & AIMS: :Control of osteoblastic bone formation involves the cumulative action of numerous transcription factors, including both activating and repressive functions that are important during specific stages of differentiation. The nuclear receptor retinoic acid receptor-related orphan receptor β (Rorβ) has been recently shown to suppress the osteogenic phenotype in cultured osteoblasts, and is highly upregulated in bone marrow-derived osteogenic precursors isolated from aged osteoporotic mice, suggesting Rorβ is an important regulator of osteoblast function. However the specific gene expression patterns elicited by Rorβ are unknown. Using microarray analysis, we identified 281 genes regulated by Rorβ in an MC3T3-E1 mouse osteoblast cell model (MC3T3-Rorβ-GFP). Pathway analysis revealed alterations in genes involved in MAPK signaling, genes involved in extracellular matrix (ECM) regulation, and cytokine-receptor interactions. Whereas the identified Rorβ-regulated ECM genes normally decline during osteoblastic differentiation, they were highly upregulated in this non-mineralizing MC3T3-Rorβ-GFP model system, suggesting that Rorβ may exert its anti-osteogenic effects through ECM disruption. Consistent with these in vitro findings, the expression of both RORβ and a subset of RORβ-regulated genes were increased in bone biopsies from postmenopausal women (73±7 years old) compared to premenopausal women (30±5 years old), suggesting a role for RORβ in human age-related bone loss. Collectively, these data demonstrate that Rorβ regulates known osteogenic pathways, and may represent a novel therapeutic target for age-associated bone loss.

背景与目标： : 控制成骨细胞骨形成涉及许多转录因子的累积作用，包括在分化的特定阶段重要的激活和抑制功能。最近，核受体视黄酸受体相关孤儿受体 β (ror β) 已被证明可以抑制培养的成骨细胞的成骨表型，并且在从老年骨质疏松小鼠分离的骨髓来源的成骨前体中高度上调，表明ror β 是重要的成骨细胞功能调节剂。然而，ror β 引起的特定基因表达模式尚不清楚。使用微阵列分析，我们在MC3T3-E1小鼠成骨细胞模型 (MC3T3-Rorβ-GFP) 中鉴定出281个受ror β 调节的基因。通路分析揭示了参与MAPK信号传导的基因，参与细胞外基质 (ECM) 调控的基因以及细胞因子-受体相互作用的改变。尽管鉴定出的ror β 调控的ECM基因在成骨细胞分化过程中通常会下降，但在这种非矿化的MC3T3-Rorβ-GFP模型系统中它们被高度上调，这表明ror β 可能通过ECM破坏发挥其抗成骨作用。与这些体外发现一致，与绝经前妇女 (30 ± 5岁) 相比，绝经后妇女 (73 ± 7岁) 的骨活检中ror β 和ror β 调控基因的子集的表达均增加，表明ror β 在人类与年龄相关的骨丢失中的作用。总的来说，这些数据表明ror β 调节已知的成骨途径，并可能代表与年龄相关的骨丢失的新治疗靶标。

BACKGROUND & AIMS: :The porcine adenovirus type 3 (PAd3) genome between map units 0 and 13.7 was sequenced and compared with similar regions of other adenoviruses. This region consists of the left inverted terminal repeat sequences involved in DNA packaging, the entire early region 1 (E1) and the protein IX (pIX) transcription unit. The lower strand contains the C-terminal end of IVa2 of the E2A transcriptional unit and two novel open reading frames (ORFs). The E1 transcription unit consists of ORFs for proteins homologous to the E1A, E1B-17k and E1B-55k of both human adenovirus type 5 (HAd5) and bovine adenovirus type 3 (BAd3). The predicted PAd3 pIX demonstrated homology with the N-terminal portion of the pIXs of HAd5 and BAd3. On the lower strand, immediately after the putative IVa2 ORF, there are two unique ORFs of 208 and 203 amino acid residues that showed homology with Epstein-Barr virus nuclear antigens and other cellular transcription factors.

背景与目标： : 对图谱单位0和13.7之间的猪腺病毒3型 (PAd3) 基因组进行了测序，并与其他腺病毒的相似区域进行了比较。该区域由参与DNA包装的左反向末端重复序列，整个早期区域1 (E1) 和蛋白质IX (pIX) 转录单元组成。下链包含E2A转录单位IVa2的C末端和两个新的开放阅读框 (orf)。E1转录单元由与E1A，E1B-17k和E1B-55k同源的人腺病毒5型 (HAd5) 和牛腺病毒3型 (BAd3) 的蛋白质的orf组成。预测的PAd3 pIX与HAd5和bad3的pIX的N末端部分具有同源性。在下链上，紧接在推定的IVa2 ORF之后，有两个独特的208和203氨基酸残基的ORF，它们与爱泼斯坦-巴尔病毒核抗原和其他细胞转录因子具有同源性。

BACKGROUND & AIMS: :Prostaglandin E2 (PGE2), a bone-resorption factor, was essentially the sole arachidonate metabolite in an osteoblastic cell line cloned from mouse calvaria (MC3T3-E1). When the cells were cultured in the presence of 2% newborn bovine serum, 1 microM epinephrine markedly stimulated PGE2 synthesis from endogenous arachidonic acid. The PGE2 synthesis commenced after a lag phase of 1-2 h, and reached a maximum at about 3 h after the addition of epinephrine. The effect of epinephrine was inhibited by propranolol, and epinephrine could be replaced by isoproterenol, suggesting beta-adrenergic stimulation of PGE2 production. A rapid increase in intracellular cAMP was observed upon the addition of epinephrine. When the intracellular cAMP level was raised using cholera toxin or forskolin, the PGE2 synthesis was also stimulated. The enhanced PGE2 synthesis was attributed to an increased level of cyclooxygenase, which was shown by immunoprecipitation of the enzyme using anti-cyclooxygenase antibody. Inhibitors of transcription and translation suppressed the epinephrine-dependent increase in cyclooxygenase activity. These findings suggest induction of cyclooxygenase involving cAMP via an as yet unclarified mechanism.

背景与目标： : 前列腺素E2 (PGE2) 是一种骨吸收因子，本质上是从小鼠颅骨 (MC3T3-E1) 克隆的成骨细胞系中唯一的花生四烯酸代谢物。当在2% 新生牛血清存在下培养细胞时，1微米肾上腺素显著刺激内源性花生四烯酸合成PGE2。PGE2合成在1-2小时的滞后阶段开始，并在添加肾上腺素后约3小时达到最大值。肾上腺素的作用被普萘洛尔抑制，肾上腺素可以被异丙肾上腺素代替，表明 β-肾上腺素能刺激PGE2的产生。添加肾上腺素后，观察到细胞内cAMP迅速增加。当使用霍乱毒素或福司可林提高细胞内cAMP水平时，也刺激了PGE2的合成。PGE2合成的增强归因于环氧合酶水平的升高，这通过使用抗环氧合酶抗体对酶进行免疫沉淀来证明。转录和翻译抑制剂抑制了肾上腺素依赖性环氧合酶活性的增加。这些发现表明，通过尚未阐明的机制诱导涉及cAMP的环氧合酶。

BACKGROUND & AIMS: :Acute liver damage is considered to be the major cause of mortality after massive hepatectomy. Prostaglandin E1 (PGE1) and somatostatin (SST) have been shown to protect against hepatic injury of rats after partial hepatectomy. However, the precise mechanisms remain largely unknown. In this study, we examined the effects of PGE1, SST and the combination of these two drugs on acute liver damage of rats after 90% hepatectomy. We found that animal survival was improved when pretreated with PGE1 and SST. Portal venous pressure (PVP), serum alanine aminotransferase (ALT) and aspartate aminotransaminase (AST), tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were all reduced after administration of PGE1 and SST. In addition, apoptosis was inhibited via upregulation of Bcl-2 and downregulation of Bax and caspase-3 in drug treatment groups. Furthermore, pretreatment with PGE1 and SST alleviated endoplasmic reticulum (ER) stress by induction of heat shock protein 70 (HSP70) and glucose-regulated protein 78 (GRP78), but suppression of transcription factor C/EBP homologous protein (CHOP). Our data suggest that administration of PGE1 and SST, particularly in combination, may prevent acute liver damage of rats after massive hepatectomy by inhibiting inflammatory responses, apoptosis and ER stress.

背景与目标： : 急性肝损伤被认为是大规模肝切除术后死亡的主要原因。前列腺素E1 (PGE1) 和生长抑素 (SST) 已显示出对部分肝切除术后大鼠肝损伤的保护。然而，确切的机制在很大程度上仍然未知。在这项研究中，我们检查了PGE1，SST和这两种药物的组合对90% 肝切除术后大鼠急性肝损伤的影响。我们发现，用PGE1和SST预处理可改善动物的存活率。给予PGE1和SST后，门静脉压力 (PVP)，血清丙氨酸氨基转移酶 (ALT) 和天冬氨酸氨基转氨酶 (AST)，肿瘤坏死因子-α (TNF-α) 和interleukin-6 (IL-6) 均降低。此外，在药物治疗组中，通过上调Bcl-2和下调Bax和caspase-3来抑制细胞凋亡。此外，PGE1和SST预处理可通过诱导热休克蛋白70 (HSP70) 和葡萄糖调节蛋白78 (GRP78) 减轻内质网 (ER) 应激，但抑制转录因子C/EBP同源蛋白 (CHOP)。我们的数据表明，PGE1和SST的给药，特别是联合给药，可以通过抑制炎症反应，凋亡和内质网应激来预防大肝切除术后大鼠的急性肝损伤。

BACKGROUND & AIMS: :Histomorphometry and biochemical markers of bone turnover have shown that, although osteoclast activity is increased in multiple myeloma (MM), mostly through the receptor activator of nuclear factor-kappaB ligand/osteoprotegerin axis, the key element in vivo to determine the presence or absence of osteolytic lesions resides on the presence and activity of osteoblasts. The loss of bone observed in MM is the result of an uncoupling of bone formation and bone resorption. Bortezomib is a first-in-class proteasome inhibitor developed as an antineoplastic agent with marked activity in relapsed/refractory MM. Response to bortezomib has been related to a significant increase in alkaline phosphatase (ALP). Increased ALP in patients responding to bortezomib was associated with a parallel increase in bone-specific ALP and parathyroid hormone, suggesting that response to bortezomib in MM is closely associated with osteoblastic activation. Variation in markers of osteoblastic activation (such as ALP) have also predicted response and response duration in patients with myeloma treated with bortezomib (P < 0.0001). This clinical observation has been confirmed in an experimental mouse model for primary human myeloma. The consequences of increased bone anabolism on myeloma growth need to be closely evaluated in prospective trials.

背景与目标： : 骨转换的组织形态计量学和生化标志物表明，尽管破骨细胞活性在多发性骨髓瘤 (MM) 中增加，但主要是通过核因子-kappaB配体/骨保护素轴的受体激活剂，体内确定是否存在溶骨性病变的关键因素在于成骨细胞的存在和活性。在MM中观察到的骨丢失是骨形成和骨吸收解偶联的结果。硼替佐米是一流的蛋白酶体抑制剂，被开发为抗肿瘤药，在复发/难治性MM中具有显着活性。对硼替佐米的反应与碱性磷酸酶 (ALP) 的显着增加有关。对硼替佐米有反应的患者的ALP增加与骨特异性ALP和甲状旁腺激素的平行增加有关，这表明MM对硼替佐米的反应与成骨细胞激活密切相关。成骨细胞活化标志物 (如ALP) 的变化也预测了用硼替佐米治疗的骨髓瘤患者的反应和反应持续时间 (P <0.0001)。此临床观察已在原发性人类骨髓瘤的实验小鼠模型中得到证实。需要在前瞻性试验中仔细评估骨合成代谢增加对骨髓瘤生长的影响。