基质金属蛋白酶

基质金属蛋白酶是一类分解细胞外基质组分的锌蛋白酶⒚它们在有机体生长发育中的细胞外基质逆转与重塑以及疾病中的病理损害起着极为重要的作用⒚基质金属蛋白酶的表达和活性在不同细胞水平受到严密调控,如细胞因子、生长因子以及激素的调节⒚基质金属蛋白酶以酶原形式分泌,随后被其它蛋白酶如胞浆素或非蛋白酶类化学物质如有机汞所激活⒚所有基质金属蛋白酶都受到天然抑制剂 金属蛋白酶组织抑制剂所抑制⒚两者的不平衡导致许多疾病的发生,如肿瘤侵入及转移⒚合成基质金属蛋白酶组织抑制剂所抑制,如 Ｍ ａｒｉｍ ａｓｔａｔ 能控制肿瘤转移的发生及进一步扩散⒚本文将对基质金属蛋白酶的特征、分子区域结构、底物特性、激活机制、调控方式等方面进行最新概述⒚     

基质金属蛋白酶及其组织抑制剂研究进展

基质金属蛋白酶家族是细胞外基质降解过程中的重要酶类,组织金属蛋白酶抑制剂是基质金属蛋白酶的天然抑制物。研究证实,细胞外基质中基质金属蛋白酶及其组织抑制剂的失衡与多种病理机制有关,尤其与肿瘤的侵袭和转移密切相关。本就基质金属蛋白酶及其组织抑制剂的性质、结构以及功能进行了综述。     

细胞外基质与基质金属蛋白酶

细胞外基质（ECM）是存在于细胞之间的动态网状结构,由胶原、蛋白聚糖及糖蛋白等大分子物质组成.这些大分子物质可与细胞表面上的特异性受体结合,通过受体与细胞骨架结构直接发生联系或触发细胞内的一系列信号传导而引起不同的基因表达,从而导致细胞的生长和分化.作为降解ECM成分最重要的酶-基质金属蛋白酶（MMPs）及其组织抑制因子(TIMPs)在这一过程中起着非常重要的作用.MMPs是一类依赖金属离子锌并以ECM成分为水解底物的蛋白水解酶.其在转录水平的表达受到生长因子、细胞因子及激素等因素的严格调控,在蛋白质水平其活性也受到其激活剂和抑制剂的调节. MMPs通过对ECM成分的水解来影响其降解与重组的动态平衡而参与多种细胞的生理和病理过程.     

自由基和基质金属蛋白酶介导脑缺血血脑屏障损伤的研究进展

血脑屏障的破坏是引起脑缺血损伤及继发水肿、出血、炎症的微观原因。缺血缺氧和再灌注过程产生的自由基,以及后续基质金属蛋白酶的激活,是破坏血脑屏障结构和功能的重要分子机制。因而,在脑缺血早期及时抑制自由基产生并清除自由基,抑制基质金属蛋白酶的活性,是降低脑缺血血脑屏障损伤及其并发症的关键环节。本文将从血脑屏障损伤的角度,概述自由基与基质金属蛋白酶在脑缺血损伤过程中的作用。     

基质金属蛋白酶及其抑制剂

基质金属蛋白酶（matrix metalloproteinases,MMP)是降解细胞外基质成分的主要酶类,参与很多重要的生理和病理过程。MMP具有典型的多结构组成,MMP活性在基因转录,酶原激活和内源性抑制等方面受到严重调控,调控的紊乱将导致肿瘤扩散和转移,风湿性关节炎等重大疾病的发生,因此MMP成为治疗这些疾病的理想的药物作用靶点,寻找高亲和性,高选择以及高生物利用度的MMP抑制剂成为一项有意义的工作。     

基质金属蛋白酶及其抑制剂在乳腺癌中的表达

目的:研究基质金属蛋白酶2(Matrix Metalloproteinase-2,MMP-2),基质金属蛋白酶7(MMP-7),基质金属蛋白酶9(MMP-9),膜型基质金属蛋白酶(Membrane Type-1 Matrix Metalloproteinase,MT1-MMP),金属蛋白酶组织抑制剂1(Tissue Inhibitor of Metalloproteinase,TIMP-1),金属蛋白酶组织抑制剂2(TIMP-2)在乳腺癌组织中mRNA的表达,及与临床病理变量之间的关联。方法:采用150例乳腺癌患者的组织样本。使用半定量逆转录-聚合酶链反应(RT-PCR)法来测定肿瘤组织和正常乳腺组织中MMP-2,MMP-7,MMP-9,MT1-MMP,TIMP-1和TIMP-2的mRNA表达。结果:MMP-2,MMP-7,MMP-9,MT1-MMP,TIMP-1和TIMP-2在乳腺癌中的mRNA表达显著高于正常组织。结论:MMP-2,MMP-7,MMP-9,和MTI-MMP的表达增加和临床病理参数之间的关联,可以用来预测乳腺癌的侵害行为。     

基质金属蛋白酶及其抑制剂mRNA在正常及异位子宫内膜中的表达

目的：观察正常及异位子宫内膜中基质金属蛋白酶－1,－2（MMP－1,－2）和基质金属蛋白酶组织抑制剂－1（TIMP－1）基因表达的变化,以探讨其与子宫内膜异位症的关系。方法：应用原位技术,采用地高辛生物素标记的cDNA探针（MMP－1,MMP－2,TIMP－1）对子宫内膜异位症患者（EM组）的子宫内膜（14例）、异位病灶组织（20例）及非子宫内膜异位症患者（对照组）的子宫内膜（12例）,分3批进行分子杂交检测,结果：3批结果相似。MMP－1,－2,TIMP－1mRNA在腺上皮细胞和间质细胞均有表达,EM组的子宫内膜MMP－1,－2及TIMP－1mRNA表达量与对照组无显著性差异（P＞0．05）,异位病灶组织的MMP－1,－2mRNA表达量明显高于对照组（P＜0．05）,而TIMP－1mRNA表达量则低于对照组（P＜0．05）。结论：子宫内膜异位症患者的异位病灶中,存在MMP－1,－2和TIMP－1明显的平衡失调,这可能与子宫内膜异位症的发生、发展和不孕有关。     

基质金属蛋白酶-9及其抑制剂mRNA在吸烟大鼠肺组织中的表达

目的 研究吸烟大鼠肺组织和肺泡巨噬细胞中基质金属蛋白酶9(MMP-9)和金属蛋白酶组织抑制剂-1(TIMP-1)基因的表达,探讨其在细胞外基质重塑中的作用。方法 建立吸烟大鼠模型,随机分为对照组和吸烟1、2、3、4、5及6月组(每组10只),用原位杂交技术检测肺组织和肺泡巨噬细胞MMP-9和TIMP-1 mRNA表达,用免疫组织化学技术观察Ⅳ型胶原在肺内的表达。结果 吸烟组肺组织和肺泡巨噬细胞MMP-9 mRNA的表达逐渐上升,至吸烟6月时均达高峰;而TIMP-1 mRNA的表达渐上升,至吸烟3～4月时达高峰,后逐步下降;肺组织Ⅳ型胶原的表达在吸烟3月时达高峰,然后渐降。结论 MMP-9／TIMP-1的动态平衡在吸烟大鼠肺气肿模型肺组织的细胞外基质重塑中有重要作用。     

基质金属蛋白酶和组织金属蛋白酶抑制剂在肾细胞癌组织中的表达

目的:基质金属蛋白酶及组织金属蛋白酶抑制剂在肾细胞癌转移中占有重要的作用,研究肾细胞癌组织中MMP-2、MMP-9、TIMP-1和TIMP-2的表达情况,为肾癌转移的治疗提供理论依据。方法:选取36例肾细胞癌肾组织标本,从相同的肾细胞癌组织及癌旁肾组织获得对照样本,均进行根治性肾切除手术切除。肿瘤分期按TNM分期标准。为了统计评估,肿瘤1期和2期为低级,3期以上为高级。RT-PCR检测肿瘤和正常组织中的MMP-2、MMP-9、TIMP-1和TIMP-2的表达。结果:不同样本MMPs和TIMPs表达水平各不相同。肾细胞癌组织中MMP-2、MMP-9、TIMP-1、TIMP-2在肾细胞癌中的表达明显高于正常肾组织(P0.05)。在肾细胞癌的肿瘤分期方面,MMP-2与MMP-9和肿瘤的分期显著相关,随着肿瘤分期的增加,MMP-2与MMP-9的表达明显升高(P0.05),而TIMP-1与TIMP-2与肿瘤的分期无关。结论:肾细胞癌组织中TIMP-2、MMP-2,MMP-9,TIMP-1的mRNA表达显著高于正常肾组织,抑制MMPS的表达将成为治疗肾细胞癌转移的新的方向。     

基质金属蛋白酶与心肌重塑

细胞外基质参与和促进了心肌重塑的过程,基质金属蛋白酶是调节细胞外基质重要的酶,基质金属蛋白酶在心肌重塑过程表达变化可分为三个时相,其活性受到信号传导途径、炎症因子和活性氧/活性氮的调节,基质金属蛋白酶可能作为心肌梗塞等疾病治疗的靶标     

Advances in assays of matrix metalloproteinases (MMPs) and their inhibitors

Matrix metalloproteinases (MMPs) play an important role in many physiological and pathological processes. To assay the activities of MMPs is important in diagnosis and therapy of the MMPs associated diseases, such as neoplastic, rheumatic and cardiovascular diseases. Several assay systems have been developed, which include bioassay, zymography assay, immunoassay, fluorimetric assay, radio isotopic assay, phage-displayed assay, multiple-enzyme/multiple-reagent assay and activity-based profiling assay. The principle, application, advantage and disadvantage of these assays have been reviewed in this article.     

Matrix metalloproteinases and gastrointestinal cancers: Impacts of dietary antioxidants

The process of carcinogenesis is tightly regulated by antioxidant enzymes and matrix degrading enzymes, namely, matrix metalloproteinases(MMPs). Degradation of extracellular matrix(ECM) proteins like collagen, proteoglycan, laminin, elastin and fibronectin is considered to be the prerequisite for tumor invasion and metastasis. MMPs can degrade essentially all of the ECM components and, most MMPs also substantially contribute to angiogenesis, differentiation, proliferation and apoptosis. Hence, MMPs are important regulators of tumor growth both at the primary site and in distant metastases; thus the enzymes are considered as important targets for cancer therapy. The implications of MMPs in cancers are no longer mysterious; however, the mechanism of action is yet to be explained. Herein, our major interest is to clarify how MMPs are tied up with gastrointestinal cancers. Gastrointestinal cancer is a variety of cancer types, including the cancers of gastrointestinal tract and organs, i.e., esophagus, stomach, biliary system, pancreas, small intestine, large intestine, rectum and anus. The activity of MMPs is regulated by its endogenous inhibitor tissue inhibitor of metallopro-teinase(TIMP) which bind MMPs with a 1:1 stoichiometry. In addition, RECK(reversion including cysteinerich protein with kazal motifs) is a membrane bound glycoprotein that inhibits MMP-2,-9 and-14. Moreover, α2-macroglobulin mediates the uptake of several MMPs thereby inhibit their activity. Cancerous conditions increase intrinsic reactive oxygen species(ROS) through mitochondrial dysfunction leading to altered protease/anti-protease balance. ROS, an index of oxidative stress is also involved in tumorigenesis by activation of different MAP kinase pathways including MMP induction. Oxidative stress is involved in cancer by changing the activity and expression of regulatory proteins especially MMPs. Epidemiological studies have shown that high intake of fruits that rich in antioxidants is associated with a lower cancer incidence. Evidence indicates that some antioxidants inhibit the growth of malignant cells by inducing apoptosis and inhibiting the activity of MMPs. This review is discussed in six subchapters, as follows.     

Matrix metalloproteinases (MMPs): chemical-biological functions and (Q)SARs

Matrix metalloproteinases (MMPs) are a large family of calcium-dependent zinc-containing endopeptidases, which are responsible for the tissue remodeling and degradation of the extracellular matrix (ECM), including collagens, elastins, gelatin, matrix glycoproteins, and proteoglycan. They are regulated by hormones, growth factors, and cytokines, and are involved in ovarian functions. MMPs are excreted by a variety of connective tissue and pro-inflammatory cells including fibroblasts, osteoblasts, endothelial cells, macrophages, neutrophils, and lymphocytes. These enzymes are expressed as zymogens, which are subsequently processed by other proteolytic enzymes (such as serine proteases, furin, plasmin, and others) to generate the active forms. Matrix metalloproteinases are considered as promising targets for the treatment of cancer due to their strong involvement in malignant pathologies. Clinical/preclinical studies on MMP inhibition in tumor models brought positive results raising the idea that the development of strategies to inhibit MMPs may be proved to be a powerful tool to fight against cancer. However, the presence of an inherent flexibility in the MMP active-site limits dramatically the accurate modeling of MMP-inhibitor complexes. The interest in the application of quantitative structure-activity relationships (QSARs) has steadily increased in recent decades and we hope it may be useful in elucidating the mechanisms of chemical-biological interactions for this enzyme. In the present review, an attempt has been made to explore the in-depth knowledge from the classification of this enzyme to the clinical trials of their inhibitors. A total number of 92 QSAR models (44 published and 48 new formulated QSAR models) have also been presented to understand the chemical-biological interactions. QSAR results on the inhibition of various compound series against MMP-1, -2, -3, -7, -8, -9, -12, -13, and -14 reveal a number of interesting points. The most important of these are hydrophobicity and molar refractivity, which are the most important determinants of the activity.     

Assays of matrix metalloproteinases (MMPs) activities: a review

Measurement of matrix metalloproteinase (MMP) activity often remains a challenge, mainly in complex media. Two sets of methods are currently used. The first one measures the hydrolysis of natural protein substrates (labeled or not) and includes the popular zymography. These techniques which are quite sensitive, cannot generally be carried out on a continuous basis. The second one takes mainly advantage of the increase of fluorescence, which is associated to the hydrolysis of initially quenched fluorogenic peptide substrates. Quite recently, another group, which is a compromise between the other two, has been developed. It measures the hydrolysis of synthetic triple-helical peptide substrates. These different methods are described and discussed.     

Matrix metalloproteinases and their expression in mammary gland

The matrix metalloproteinases (MMPs) are a family of zine-dependent endopeptidases that play a key role in both normal and pathological processes involving tissue remodeling events.The expression of these proteolytic enzymes is highly regulated by a balance between extracellular matrix (ECM) deposition and its degradation,and is controlled by growth factors,cytokines,hormones,as well as interactions with the ECM macromolecules.Furthermore,the activity of the MMPs is regulated by their natural endogenous inhibitors,which are members of the tissue inhibitor of metalloproteinases (TIMP) family.In the normal mammary gland,MMPs are expressed during ductal development,lobulo-alveolar development in pregnancy and involution after lactation.Under pathological conditions,such as tumorigenesis,the dysregulated expression of MMPs play a role in tumor initiation,progression and malignant conversion as well as facilitating invasion and metastasis of malignant cells through degradation of the ECM and basement membranes.     

Temporospatial expression of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases in mouse antigen-induced arthritis

Several lines of evidence speak for an important role of matrix metalloproteinases (MMPs) in the development of progressive joint destruction. To better understand the role of MMPs and their tissue inhibitors (TIMPs) in this process, we have used the antigen-induced arthritis model to study the temporospatial expression of several MMPs and TIMPs during the progression of arthritis. Arthritis was induced by a single intra-articular injection of methylated bovine serum albumin (mBSA) into one or both knee joints of adult mice previously immunised against mBSA. Samples were collected at 3, 7, 21 and 42 days after induction of arthritis for histology and RNA extraction, and analysed by Northern hybridisation, histochemistry and immunohistochemistry for production of several MMPs and TIMPs −1, −2 and −3. A systematic analysis of MMP and TIMP mRNA levels in mouse knee joints demonstrated a general upregulation of both MMPs and TIMPs during progression of arthritis. Upregulation of MMP-9, −13 and −14 coincided with the advancement of cartilage degeneration, but the expression patterns of MMP-9 and −13 also followed the course of synovial inflammation. TIMPs were steadily upregulated throughout the examination period. Immunohistochemical localisation of MMPs and TIMPs suggested the synovium to be the major source of MMP and TIMP production in arthritis, although articular cartilage chondrocytes also showed an increased production of both MMPs and TIMPs.     

Effect of compressive force on the expression of MMPs, PAs, and their inhibitors in osteoblastic Saos-2 cells

Bone matrix turnover is regulated by matrix metalloproteinases (MMPs), tissue inhibitors of matrix metalloproteinases (TIMPs), and the plasminogen activation system, including tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), and plasminogen activator inhibitor type-1 (PAI-1). We previously demonstrated that 1.0g/cm(2) of compressive force was an optimal condition for inducing bone formation by osteoblastic Saos-2 cells. Here, we examined the effect of mechanical stress on the expression of MMPs, TIMPs, tPA, uPA, and PAI-1 in Saos-2 cells. The cells were cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum and with or without continuously compressive force (0.5-3.0g/cm(2)) for up to 24h. The levels of MMPs, TIMPs, uPA, tPA, and PAI-1 gene expression were estimated by determining the mRNA levels using real-time PCR, and the protein levels were determined using ELISA. The expression levels of MMP-1, MMP-2, MMP-14, and TIMP-1 markedly exceeded the control levels at 1.0g/cm(2) of compressive force, whereas the expression levels of MMP-3, MMP-13, TIMP-2, TIMP-3, TIMP-4, tPA, uPA, and PAI-1 markedly exceeded the control levels at 3.0g/cm(2). These results suggest that mechanical stress stimulates bone matrix turnover by increasing these proteinases and inhibitors, and that the mechanism for the proteolytic degradation of bone matrix proteins differs with the strength of the mechanical stress.     

The effect of IL-1alpha on the expression of matrix metalloproteinases, plasminogen activators, and their inhibitors in osteoblastic ROS 17/2.8 cells

Interleukin-1 (IL-1) plays key roles in altering bone matrix turnover. This turnover is regulated by matrix metalloproteinases (MMPs), tissue inhibitor of matrix metalloproteinases (TIMPs), and the plasminogen activation system, including tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA) , and plasminogen activator inhibitor type-1 (PAI-1). In this study, we examined the effect of IL-1alpha on the expression of the MMPs, TIMPs, tPA, uPA, and PAI-1 genes in osteoblasts derived from the rat osteosarcoma cell line ROS 17/2.8. The cells were cultured in alpha-minimum essential medium containing 10% fetal bovine serum with 0 or 100 U/ml of IL-1alpha for up to 14 days. The levels of MMPs, TIMPs, uPA, tPA, and PAI-1 expression were estimated by determining the mRNA levels using real-time RT-PCR and by determining protein levels using ELISA. In IL-1alpha cultures, the expression levels of MMP-1, -2, -3, -13, and -14 exceeded that of the control through day 14 of culture, and the expression of MMPs increased markedly from the proliferative to the later stages of culture. The TIMP-1, -2, and -3 expression levels increased from the initial to the proliferative stages of culture. The expression of tPA increased greatly during the proliferative stage of culture, and uPA expression increased throughout the culture period, increasing markedly from the proliferative to the later stages of culture. In contrast, PAI-1 expression decreased in the presence of IL-1alpha through day 14. These results suggest that IL-1alpha stimulate bone matrix turnover by increasing MMPs, tPA, and uPA production and decreasing PAI-1 production by osteoblasts, and incline the turnover to the resolution.     

白血病抑制因子对胚泡金属蛋白酶表达的影响

为了探讨白血病抑制因子 (LIF) 对胚泡着床作用的机理,胚泡经与LIF及其特异性抗体培养后,通过RT-PCR及免疫印迹技术,分析了LIF与着床前小鼠胚泡的基质金属蛋白酶9(MMP9)表达和分泌之间的关系.结果显示：LIF可明显诱导胚泡MMP9的分泌和基因表达; 经LIF特异性抗体封闭后,胚泡MMP9的分泌及基因表达下降,且下降趋势随着LIF被封闭时间延长而减弱,对MMPs组织抑制因子1(TIMP1)的影响则不明显.说明LIF可能通过诱导MMP9的分泌及基因表达来影响胚泡对子宫内膜细胞外基质的水解,促进着床.