TGF—β在骨关节炎发生中的可能作用

转化生长因子TGF－β具有广泛的生理效应,对于维持关节软骨正常有重要意义。软骨细胞外基质降解和关节软骨损坏是骨关节炎的重要特征,研究表明TGF－β－方面通过调节细胞外基质成分含量维持基质的正常更新,另一方面通过调节关节软骨细胞的形成,增殖和分化来保持正常数量和正常生理状态的软骨细胞,本文就这两个方面综述了最新研究进展,以探讨TGF－β在骨关节炎发生中的可能调节机制。     

Smad在TGF-β超家族信号通路中的调控作用

TGF家族蛋白在哺乳动物的器官发育及形成中起着重要作用,它们经过膜受体的介导将信号传入细胞内,其下游最主要的调控蛋白Smad在胞内通过不同的调节各种基因的表达,这些模式主要有RSmadSmad4复合物直接与DNA结合,Smad蛋白与其他DNA结合因子,Smad蛋白与非DNA结合因子间的相互作用。Smad在BMPs对成骨细胞的分化调节过程中与RasMAPKAP1通路关联,共同决定不同细胞在不同发育阶段的定向分化 。     

骨桥蛋白在骨关节炎中的研究进展

骨关节炎（osteoarthritis,OA）是临床最常见的一类关节疾病,表现为关节软骨纤维化、皲裂、溃疡、脱失等进行性关节软骨破坏及关节边缘骨赘形成,并伴有不同程度的滑膜炎症。随着我国社会老龄化进程的加剧,OA发病率有逐年增高的趋势。据一项流行病学资料表明,我国40岁以上的中老年群体中,OA发病率高达46.3%,其中大约有80%的人群存在关节活动受限。     

TGF-β家族信号的细胞内传导蛋白:SMAD蛋白家族

SMADs是新近发现的参与TGFβ超家族的信号在细胞内传导的一族蛋白,包括8个成员,分别称SMAD1～8。SMAD1、2、3、5和8属于一类,它们被TGFβ的受体或BMP的受体激活而磷酸化,称为受体调节SMAD,传导TGFβ或BMP的信号。SMAD6和7属于另一类,它们抑制受体调节SMAD的信号传导。SMAD4是第三类,它是受体调节SMAD传导信号的伴侣。受体调节SMAD传导信号必须先与SMAD4结合形成异源复合物,才能进到核中,调节转录活动 。     

重组人TGF-β3的表达纯化及复性研究

利用大肠杆菌表达重组人转化生长因子β3(humantransformgrowthfactor,hTGFβ3),目的蛋白以包涵体形式表达。用8mol/L尿素溶解的包涵体蛋白,经CMSepharoselFastFlow柱和SphacrylS100分子筛可获得纯度达90%以上的rhTGF-β3单体。将单体蛋白加到复性缓冲液(1mol/LNaCl,0.5mol/LLArg,0.5mmol/LGSSG,30mmol/LCHAPS,20%(v/v)DMSO)进行复性后,再经DEAESepharoselFastFlow柱和SphacrylS100分子筛可分离得到纯度达94%的二聚体rhTGFβ3,纯化后的产量为720mg/L,纯化总回收率为47%。MTT法测活表明,该重组蛋白具刺激成纤维细胞Balb/c3T3生长的作用。     

CircRNAs在骨关节炎发生发展中的作用

环状RNA(circular RNAs,circ RNAs)是一类在真核细胞中广泛存在的非编码RNA。与传统的线性RNA不同,环状RNA无5’末端帽子和3’末端多聚A尾,而是形成一个共价闭合的环状结构。最初,人们认为circ RNAs是前体m RNA(pre-m RNA)发生错误剪接而形成的低丰度RNA分子,没有给予足够重视。随着高通量RNA测序技术和生物信息学的发展,大量circ RNAs被鉴定出来,对其认识也逐渐深入,发现circ RNAs具有重要的生物学功能,在充当mi RNA"海绵"、调控基因转录与表达等方面发挥着重要作用。近几年研究发现,circ RNAs在骨关节炎(osteoarthritis,OA)关节软骨与正常软骨中表达出现差异。部分表达差异的circ RNAs参与调节了与OA发生发展密切相关的软骨细胞外基质(extracellular matrix,ECM)降解、炎症反应、软骨细胞凋亡等过程。尤其是,小干扰RNA(small interfering RNAs,si RNAs)沉默circ RNA-CER后,可促进软骨细胞ECM生成,提示circ RNAs可能成为治疗OA的新靶点。本文将在简单综述circ RNAs的生物合成、主要生物功能的基础上,重点综述circ RNAs与OA发生发展之间的关系,以期为OA的诊断和特异性治疗提供新靶点和新治疗措施。     

NF-κB信号通路在骨关节炎中的作用

骨关节炎(osteoarthritis, OA)是一种世界范围的慢性退行性关节疾病,对其发病机制的研究一直是临床研究的热点问题。核因子-κB(nuclear factor-kappa B, NF-κB)信号通路参与软骨退化、滑膜炎症、软骨下硬化等OA重要病理过程,与OA的发生和发展关系密切,或可成为OA治疗的潜在新靶点。本文就NF-κB信号通路在OA发病中的研究成果进行综述,以期更好地了解其发病机制,为OA的诊疗提供参考和依据。     

滑膜细胞在骨关节炎中的研究进展

骨关节炎(osteoarthritis,OA)作为最常见的退行性关节疾病,其主要临床特点是软骨的破坏降解,进而导致关节功能丧失,严重影响患者的生活质量.越来越多的证据表明,除了软骨组织,OA的病理改变还涉及滑膜、骨以及软骨下骨在内的多个组织系统.其中,滑膜作为组织系统的重要组成部分,其病变在OA中的作用日益突出.滑膜细...     

骨关节炎软骨细胞发生内质网应激

目的：研究骨关节炎软骨细胞是否发生内质网应激现象。方法：对关节置换术后的人类骨关节炎软骨标本和正常关节软骨标本切片进行内质网应激标志分子免疫球蛋白重链结合蛋白（BiP）的免疫组织化学检测;对小鼠膝关节进行半月板切断术诱发实验性骨关节炎,在术后1、3和6周取材,对组织切片进行番红花“O”染色、Mankin评分及BiP的免疫组织化学检测。结果：所有人类骨关节炎标本中软骨细胞BiP的表达明显升高。番红花“O”染色结果表明,在小鼠骨关节炎模型中,全部手术侧关节表面发生磨损,且随着术后时间延长关节表面磨损范围逐步扩大,手术侧Mankn分值显著高于对照侧;此外,手术侧的软骨细胞内BiP呈阳性表达,且表达量随术后时间延长而增加。结论：在人类骨关节炎标本和实验性小鼠骨关节炎模型中,关节软骨细胞均发生明显的内质网应激现象。     

MMP-14 mediated MMP-9 expression is involved in TGF-beta1-induced keratinocyte migration

The importance of expression of matrix metalloproteinase (MMP) in keratinocyte migration is well established, but its role remains unclear. Here we investigated the function of MMP-14 in TGF-beta1-induced keratinocyte migration. TGF-beta1 stimulated cell migration and the expression of MMP-2, -9 in HaCaT human keratinocyte cells. When we lowered MMP-14 mRNA with siRNA, cell migration, and MMP-9 expression decreased. Furthermore, the MMP-14 siRNA also reduced activation of JNK in response to TGF-beta1, and a JNK-specific inhibitor decreased both cell migration and MMP-9 expression. Taken together, these results suggest that TGF-beta1-induced HaCaT cell migration is mediated by MMP-14, which regulates MMP-9 expression via JNK signaling.     

Tumor metastasis in an orthotopic murine model of head and neck cancer: possible role of TGF-beta 1 secreted by the tumor cells

In an orthotopic murine model of head and neck cancer, combined subcutaneous and intratumoral vaccination with recombinant vaccinia virus expressing interleukin-2 (rvv-IL-2) induced significant tumor regression early on therapy. However, its efficacy was restricted by recurrent tumor growth and loco-regional metastases. In this study, we explored the mechanism of tumor metastasis. We compared the levels of expression of a number of molecules involved in tumor metastasis, which included transforming growth factor-beta1 (TGF-beta1), E-cadherin, matrix metalloproteinases (MMPs): MT1-MMP, MMP-2, MMP-9, their tissue inhibitors (TIMPs): TIMP-1/TIMP-2, and pro-angiogenic factors CD31, VEGF-R2, and iNOS between primary and metastatic tumors by real-time RT-PCR and immunohistochemistry. We detected spontaneous lymph node and tongue metastasis. Metastasis was delayed in rvv-IL-2 treated mice. Cultured tumor cells expressed negligible amount of TGF-beta1. Untreated or metastatic tumors, on the other hand, expressed high levels of TGF-beta1 and secreted TGF-beta1 in the sera of tumor-bearing mice. Levels of TGF-beta1 in the sera suddenly jumped at the time when tumor metastasis started. In the metastatic tumors, levels of MT1-MMP, MMP-2, and MMP-9 were significantly elevated (P < 0.001), while levels of TIMP-1/TIMP-2 and E-cadherin were decreased (P < 0.001) compared to control or primary tumors. Levels of CD31, VEGF-R2, and iNOS were also significantly elevated in the metastatic lesions (P < 0.001). The concurrence of high levels of TGF-beta1 in the sera, expression of proteins involved in metastasis and initiation of metastasis suggested possible role of TGF-beta1 in on setting the metastatic cascade in this model.     

锌转运蛋白ZIP8 在骨关节炎中的表达及其机制研究

目的:探讨锌转运蛋白ZIP8在骨关节炎患者中的表达及其对软骨细胞生长及基质金属蛋白酶(MMPs)表达的影响。方法:收集20例骨关节炎患者(OA组)和20例非骨关节炎患者(对照组)血清和软骨组织;采用原子吸收分光光度计测定患者血清和软骨组织中锌离子的表达水平;MTT方法检测软骨细胞的生长活力;采用小RNA干扰沉默ZIP8基因的表达;实时荧光定量PCR方法检测ZIP8及金属基质蛋白酶MMP3、MMP9、MMP12和MMP13等基因的m RNA表达水平;蛋白免疫印迹检测ZIP8及MMP3、MMP9、MMP12和MMP13等蛋白的表达水平。结果:OA组的血清和软骨组织中的锌离子浓度明显高于对照组(P0.01)。OA组软骨组织中ZIP8的m RNA(P0.05)和蛋白(P0.01)表达水平显著高于对照组。ZIP8小RNA干扰片段可以有效的沉默ZIP的基因表达(P0.01);沉默ZIP8的表达促进骨关节炎患者来源的软骨细胞的生长(P0.05),并且降低基质金属蛋白酶包括MMP3,MMP9,MMP12和MMP13的表达水平(P0.05)。结论:ZIP8与骨关节炎密切相关,沉默ZIP8的表达可以提高软骨细胞的生长活力,并且抑制基质金属蛋白酶的表达,为骨关节炎的治疗提供了新的靶点。     

The structure of the TGF-beta latency associated peptide region determines the ability of the proprotein convertase furin to cleave TGF-betas

The TGF-beta family members are generated as latent pre-pro-polypeptides. The active mature peptides are cleaved from the latent forms by cellular proteases. TGF-beta 1, for instance, is predominantly processed by a substilisin-like proprotein convertase, furin. TGF-beta 2 has a consensus cleavage site for furin and therefore has been presumed to be cleaved by furin. However, TGF-beta 2 is often secreted as the latent form, which appears to be inconsistent with its postulated sensitivity to furin. We report here that both the regular (short) form of TGF-beta2 and its spliced variant with an additional exon (long form) are insensitive to furin. NIH 3T3 and CHO cells were transfected with expression vectors containing the short or long form of TGF-beta 2 or a chimeric TGF-beta consisting of the TGF-beta1 LAP region, the TGF-beta 2 cleavage site and the TGF-beta 2 mature peptide. The constructs included a c-myc epitope tag in the N-terminal region of the mature peptide. The TGF-betas produced by the transfected cells were analyzed with Western blots and immunocytochemistry. The intracellular proteins harvested from these cells were incubated with furin. Furin only inefficiently cleaved both the long and short forms of TGF-beta 2, but efficiently processed the chimeric TGF-beta. This indicates that the insensitivity of both forms of TGF-beta 2 to furin is a consequence of the tertiary structure of their LAP regions rather than their cleavage site. This differential processing of TGF-beta1 and -beta 2 may be part of the mechanism that generates isoform-specific functions of the TGF-betas.     

骨性关节炎病因的研究进展

骨性关节炎是影响人类健康及生活质量的最常见关节疾病之一,是一种以骨关节软骨退行性变和继发性周围骨质增生为特点的慢性关节疾病,又被称为退行性关节炎.多发于中老年人群,常累及全身骨关节中的脊柱、髋关节和膝关节等负重较大的关节,导致受累关节僵硬、变形,从而使关节功能受到严重影响,影响患者的生活质量。常见症状为受累关节疼痛,活动受限,休息后缓解及晨起关节僵硬感。由于人口老龄化加重,导致其发病率连年增加。但由于其病因及病机复杂多样,目前医学界还没有确切的结论,导致缺乏有效的治疗手段,本文就近几年来文献中提及的骨性关节炎病因及病机做一综述,有利于我们继续探索,早日认清这种疾病,治愈这种疾病,提高患者生活质量。     

A delicate balance: TGF-beta and the tumor microenvironment

The activated form of TGF-beta is a known regulator of epithelial cell autonomous tumor initiation, progression, and metastasis. Recent studies have also indicated that TGF-beta mediates interactions between cancer cells and their local tumor microenvironment. Specifically, the loss of TGF-beta signaling in stromal components including fibroblasts and T-cells can result in an "activated" microenvironment that supports and even initiates transformation of adjacent epithelial cells. TGF-beta signaling in cancer can be regulated through mechanisms involving ligand activation and expression of essential components within the pathway including the receptors and downstream effectors. TGF-beta signaling in the tumor microenvironment significantly impacts carcinoma initiation, progression, and metastasis via epithelial cell autonomous and interdependent stromal-epithelial interactions in vivo.     

骨性关节炎生物学标志物研究进展

骨性关节炎(oseteoarthritis,OA)是一种随着年龄增长发病率明显升高的退行性变,常累及脊柱、髋、膝等人体负重关节,以关节缓慢发展的疼痛、肿胀,伴功能障碍为临床表现,主要有滑膜增生、软骨破坏、软骨下骨骨化及骨赘形成等一系列病理表现。OA对人类的健康和生活质量影响很大,随着老龄化社会的到来,本病的发病率日趋升高,其研究已成为医学领域中的重要课题。目前,OA的早期诊断、病变监测和有效防治仍是骨科领域亟待解决的疑难问题。随着分子生物学的发展和研究手段的提高,许多研究者都在试图寻找用于临床评价OA的生物学标志物。本文将就OA研究中所使用的主要标志物进行综述,为深入研究OA提供方便。     

多种特殊染色法在骨关节炎组织形态学研究中的应用比较

目的探讨多种特殊染色法在骨关节组织中的染色规律及其在骨关节炎形态学研究中的应用价值。方法 6月龄健康新西兰大白兔20只,随机分为正常组和造模组各10只,根据改良Hulth法造模,6周后膝关节取材。对标本固定、脱钙后进行石蜡包埋和切片。分别采用HE、番红-固绿、AB-PAS、甲苯胺蓝、Van Gieson染色和Mallory染色,观察骨关节组织的形态学变化,并对几种染色方法进行比较。结果 HE染色显示关节一般组织形态结构,可见模型组关节软骨和软骨下骨发生骨性关节炎病理变化;番红-固绿染色法中软骨和软骨下骨的界限（黏合线）以及潮线显示清晰,软骨基质中糖胺聚糖含量减少,纤维成分增多;AB-PAS染色显示骨关节炎软骨基质糖胺聚糖尤其是酸性糖胺聚糖含量减少;甲苯胺蓝染色显示骨关节炎软骨的酸性糖胺聚糖减少;Van Gieson染色和Mallory染色可显示骨关节组织中的胶原纤维,但组织结构界限不够清晰。结论在骨性关节炎的组织形态学研究中,通过常规HE染色,结合番红-固绿染色法和AB-PAS染色法,能较客观全面地获得关节组织形态学相关信息。     

TGF-beta control of cell proliferation

This article focuses on recent findings that the type V TGF-beta receptor (TbetaR-V), which co-expresses with other TGF-beta receptors (TbetaR-I, TbetaR-II, and TbetaR-III) in all normal cell types studied, is involved in growth inhibition by IGFBP-3 and TGF-beta and that TGF-beta activity is regulated by two distinct endocytic pathways (clathrin- and caveolar/lipid-raft-mediated). TGF-beta is a potent growth inhibitor for most cell types, including epithelial and endothelial cells. The signaling by which TGF-beta controls cell proliferation is not well understood. Many lines of evidence indicate that other signaling pathways, in addition to the prominent TbetaR-I/TbetaR-II/Smad2/3/4 signaling cascade, are required for mediating TGF-beta-induced growth inhibition. Recent studies revealed that TbetaR-V, which is identical to LRP-1, mediates IGF-independent growth inhibition by IGFBP-3 and mediates TGF-beta-induced growth inhibition in concert with TbetaR-I and TbetaR-II. In addition, IRS proteins and a Ser/Thr-specific protein phosphatase(s) are involved in the TbetaR-V-mediated growth inhibitory signaling cascade. The TbetaR-V signaling cascade appears to cross-talk with the TbetaR-I/TbetaR-II, insulin receptor (IR), IGF-I receptor (IGF-IR), integrin and c-Met signaling cascades. Attenuation or loss of the TbetaR-V signaling cascade may enable carcinoma cells to escape from TGF-beta growth control and may contribute to the aggressiveness and invasiveness of these cells via promoting epithelial-to-mesenchymal transdifferentiation (EMT). Finally, the ratio of TGF-beta binding to TbetaR-II and TbetaR-I is a signal controlling TGF-beta partitioning between two distinct endocytosis pathways and resultant TGF-beta responsiveness. These recent studies have provided new insights into the molecular mechanisms underlying TGF-beta-induced cellular growth inhibition, cross-talk between the TbetaR-V and other signaling cascades, the signal that controls TGF-beta responsiveness and the role of TbetaR-V in tumorigenesis.