Identification,purification and partial characterization of tissue inhibitor of matrix metalloproteinase-2 in bovine pulmonary artery smooth muscle

Bovine pulmonary artery smooth muscle possesses the tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) as revealed by Western immunoblot study of its cytosol fraction with bovine polyclonal TIMP-2 antibody. This potent polypeptide inhibitor of matrix metalloproteinases (MMPs) was purified to homogeneity from cytosol fraction of bovine pulmonary artery smooth muscle. This inhibitor was purified by ammonium sulfate precipitation followed by gelatin sepharose and lentil lectin sepharose affinity chromatography and continuous elution electrophoresis by Prep Cell Model 491 (Bio-Rad, USA). SDS-PAGE revealed that the inhibitor has an apparent molecular mass of 21 kDa and was confirmed as TIMP-2 by (i) Western immunoblot assay using bovine polyclonal TIMP-2 antibody; and also by (ii) amino terminal amino acid sequence analysis of the purified inhibitor is found to be identical with TIMP-2 obtained from other sources. The purified 21 kDa inhibitor was found to be active against matrix metalloproteinase-2 (MMP-2, 72 kDa gelatinase) and matrix metalloproteinase-9 (MMP-9, 92 kDa gelatinase), the ambient MMPs in the pulmonary artery smooth muscle. The inhibitor was also found to be sensitive to the activated 72 kDa gelatinase-TIMP-2 complex and also active human interstitial collagenase. By contrast, it was found to be insensitive to the serine proteases: trypsin and plasmin. The inhibitor was heat and acid resistant and it had the sensitivity to trypsin degradation and reduction-alkylation. Treatment of the inhibitor with hydrogen peroxide, superoxide generating system (hypoxanthine plus xanthine oxidase) and peroxynitrite inactivated the inhibitor.     

Purification and characterization of a collagenase inhibitor produced by bovine vascular smooth muscle cells

A potent polypeptide inhibitor of mammalian collagenases was purified to homogeneity from medium conditioned by bovine aortic smooth muscle cells maintained in culture. This inhibitor was purified by a series of molecular sieve and heparin-Sepharose chromatographic procedures; it had an apparent Mr of 28,500 and was a major protein secreted by the smooth muscle cells. It was found to be active against several mammalian collagenases including those obtained from rabbit and human fibroblasts and a tumor-specific type IV collagenase. In contrast, it had minimal inhibitory activity for bacterial collagenase and was inactive against the serine proteases plasmin and trypsin. The inhibitor shared many characteristics with tissue inhibitor of metalloproteinases including the ability to irreversibly inhibit susceptible proteinases, heat and acid resistance, and sensitivity to trypsin degradation and reduction-alkylation. A polyclonal rabbit antiserum with blocking activity which recognized the Mr 28,500 protein was obtained. This inhibitor, which is likely produced by bovine vascular smooth muscle cells in vivo to protect the collagen matrix of blood vessels, may play an important role in pathological conditions associated with alteration of collagen metabolism in tissues.     

Identification,purification and characterization of matrix metalloproteinase-2 in bovine pulmonary artery smooth muscle plasma membrane

Bovine pulmonary artery smooth muscle tissue possesses matrix metalloproteinase-2 (72 kDa gelatinase: MMP-2; E.C. 3.4.24.24) as revealed by immunoblot studies of its plasma membrane suspension with polyclonal MMP-2 antibody. In this report, we described the purification and partial characterization of MMP-2 in the plasma membrane fraction of the smooth muscle. MMP-2 has been purified from plasma membrane fraction of bovine pulmonary artery smooth muscle to homogeneity using a combination of purification steps. Heparin sepharose purified preparation of 72 kDa progelatinase is composed of two distinct population of zymogens: a 72 kDa progelatinase tightly complexed with TIMP-2 (an ambient tissue inhibitor of metalloprotease in the smooth muscle plasma membrane), and a native 72 kDa progelatinase free of any detectable TIMP-2. The homogeneity of the native 72 kDa progelatinase form is demonstrated by SDS-PAGE under non-reducing condition, non-denaturing native gel electrophoresis. The purified TIMP-2 free proenzyme electrophoresed as a single band of 72 kDa which could be activated by APMA with the formation of 62 and 45 kDa active species. The proenzyme is activated poorly by trypsin but not by plasmin. The purified 72 kDa progelatinase is stable at aqueous solution and does not spontaneously autoactivate. The purified 72 kDa gelatinase exhibited properties that are typical of MMP-2 obtained from other sources. These are: (i) its activity is dependent on the divalent cation, Ca+2, and is inhibited by EDTA, EGTA and 1:1 0-phenanthroline; (ii) it was inhibited by a, macroglobulin but not by the inhibitors of serine, cysteine, thiol, aspartic proteinases and calpains; (iii) it was found to be inhibited by TIMP-2, the specific inhibitor of MMP-2; (iv) like MMP-2, obtained from other sources, its major substrates were found to be collagens (type IV and V) and gelatins (type I, IV and V). Additionally, the purified MMP-2 degrades Dnp-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg-OH (dinitrophenyl labelled peptide), a well known synthetic substrate for the MMP-2.     

Matrix metalloproteinase-9,-3 and tissue inhibitor of matrix metalloproteinase-1 in colorectal cancer: relationship to clinicopathological variables

The balance between matrix metalloproteinases (MMPs) and their physiological tissue inhibitors of matrix metalloproteinases (TIMPs) is crucial in tumour invasion and progression. The aim of this study was to investigate the levels of MMP-9, MMP-3 and TIMP-1 in colorectal cancer (CRC) and to evaluate these proteinases and their inhibitor with respect to clinicopathological variables. Activities of pro- and active MMP-9 were measured in paired tumour and distant normal tissue specimens from 43 patients with CRC using gelatin zymography. ELISA was employed for the determination of MMP-9, MMP-3 and TIMP-1 protein expressions. The activity levels of pro- and active MMP-9 and protein expression levels of MMP-9, MMP-3 and TIMP-1 were higher in tumour tissues than in the corresponding normal tissues; the differences being significant for all (p < 0.05), except TIMP-1. Similarly, active MMP-9/proMMP-9 and the ratio of protein expression level of MMP-9-TIMP-1 were found to be significantly higher in tumour tissues ( p < 0.01). Among all the clinicopathological variables investigated, significant correlations were found between MMP-9 and presence of perineural invasion, MMP-3 and lymph node status, TIMP-1 and tumour differentiation, MMP-9/TIMP-1 ratio and histological types ( p < 0.05). In conclusion, MMP-3 was not as notably increased as MMP-9 in tumour tissues. However, different roles may be attributed to MMP-9 and MMP-3 in CRC development and progression. Additionally, assessment of TIMP-1 in relation to MMPs appeared to be crucial in CRC studies to provide a basis for the re-evaluation of the clinical usefulness of TIMP-1 in colorectal cancer.     

基质金属蛋白酶- 9, 组织抑制因子- 1 在进展期 胃癌中的表达与意义

目的：研究基质金属蛋白酶-9（matrix metalloproteinase-9,MMP-9）及其组织抑制因子-1（tissue inhibitor of metallopmteinase—1,TMP-1）在进展期胃癌中的表达情况,探讨二者的表达与胃癌侵袭转移闻的关系及二者间的联系。方法：应用免疫组化方法检测70例进展期胃癌标本中MMP-9,TIMP-1的表达,并进行回顾性随访。结果：馒反肌层以上者MMP-9的阳性表达（66．67％）明显高于肿瘤局限于粘膜、粘膜下者（20％P〈0.01）。MMP-9阳性表达与胃癌的淋巴转移与肝转移有相关性（P〈0．01）。TIMP-1的表达随胃癌浸润深度增加而减少,当肿瘤突破浆膜时TIMP-1的表达呈现陡降趋势（P〈0．01）。结论：MMP-9的过阳性表达和TIMP-1的表达失衡可能与胃癌转移行为有关。TIMP-1可能抑制胃癌的浸润转移。     

Influence of organosulphur compounds from garlic on the secretion of matrix metalloproteinases and their inhibitor TIMP-1 by cultured HUVEC cells

Organosulphur compounds from garlic, especially diallyl disulphide (DADS) at non-toxic concentrations, affected production and secretion of some matrix metalloproteinases (MMPs) and of tissue inhibitor of metalloproteinase-1 (TIMP-1), one of their inhibitors, by human umbilical vein endothelial cells. Addition of DADS to the culture medium resulted in a concentration-dependent reduction of secreted MMP-2 protein and activity as well as TIMP-1 protein. In the presence of inducers (phorbol 12-myristate 13-acetate, forskolin and tumor necrosis factor alpha) addition of DADS caused a distinct concentration-dependent decrease of MMP-9 and TIMP-1 secretion, while not affecting MMP-9 mRNA levels. Intracellular protein levels remained low and were not affected. Other organosulphur compounds like allyl mercaptan and S-allylcysteine showed no or less clear effects on MMP-secretion or TIMP-1-secretion. These results suggest that DADS may mediate some of the biological effects ascribed to garlic preparations through affecting MMP-TIMP balance.     

Phage display of tissue inhibitor of metalloproteinases-2 (TIMP-2): identification of selective inhibitors of collagenase-1 (metalloproteinase 1 (MMP-1))

Tissue inhibitor of metalloproteinases-2 (TIMP-2) is a broad spectrum inhibitor of the matrix metalloproteinases (MMPs), which function in extracellular matrix catabolism. Here, phage display was used to identify variants of human TIMP-2 that are selective inhibitors of human MMP-1, a collagenase whose unregulated action is linked to cancer, arthritis, and fibrosis. Using hard randomization of residues 2, 4, 5, and 6 (L1) and soft randomization of residues 34-40 (L2) and 67-70 (L3), a library was generated containing 2 × 10(10) variants of TIMP-2. Five clones were isolated after five rounds of selection with MMP-1, using MMP-3 as a competitor. The enriched phages selectively bound MMP-1 relative to MMP-3 and contained mutations only in L1. The most selective variant (TM8) was used to generate a second library in which residues Cys(1)-Gln(9) were soft-randomized. Four additional clones, selected from this library, showed a similar affinity for MMP-1 as wild-type TIMP-2 but reduced affinity for MMP-3. Variants of the N-terminal domain of TIMP-2 (N-TIMP-2) with the sequences of the most selective clones were expressed and characterized for inhibitory activity against eight MMPs. All were effective inhibitors of MMP-1 with nanomolar K(i) values, but TM8, containing Ser(2) to Asp and Ser(4) to Ala substitutions, was the most selective having a nanomolar K(i) value for MMP-1 but no detectable inhibitory activity toward MMP-3 and MMP-14 up to 10 μM. This study suggests that phage display and selection with other MMPs may be an effective method for discovering tissue inhibitor of metalloproteinase variants that discriminate between specified MMPs as targets.     

特布他林联合羧甲司坦片治疗慢性阻塞性肺疾病的疗效及对血清MMP-9、MMP-12、TIMP-1的影响

目的:研究特布他林联合羧甲司坦片治疗慢性阻塞性肺疾病的疗效及对血清基质金属蛋白酶-9(MMP-9)、基质金属蛋白酶-12(MMP-12)、组织型金属蛋白酶抑制物(TIMP-1)水平的影响。方法:选取2015年3月至2018年2月我院收治的170例COPD患者,根据随机数字法分为观察组(87例)和对照组(83例)。对照组使用特布他林,观察组联合使用羧甲司坦。比较两组患者的临床疗效,治疗前后血清MMP-9、MMP-12、TIMP-1水平,肺功能指标,炎性因子水平的变化及不良反应的发生情况。结果:治疗后,观察组临床总有效率显著高于对照组(P<0.05),血清MMP-9、MMP-12、TIMP-1水平显著低于对照组(P<0.05),最大呼气流速(PEF)、1秒用力呼气容积(FEV1)、用力肺活量(FVC)及FEV1/FVC显著高于对照组(P<0.05),血清肿瘤坏死因子-α(TNF-α)、白细胞介素-8(IL-8)、中性粒细胞弹性蛋白酶(NE)水平均显著低于对照组(P<0.05)。观察组和对照组不良反应的发生率比较无显著差异(P>0.05)。结论:特布他林联合羧甲司坦片治疗COPD的临床疗效显著优于单用特布他林,且安全性更高,可能与其能有效降低血清MMP-9、MMP-12、TIMP-1水平有关。     

Neuroprotection from Tissue Inhibitor of Metalloproteinase-1 and its nanoparticles

Matrix metalloproteinases (MMPs) are family of zinc dependent endopeptidases, which cleave extracellular matrix proteins, and play an important role in tissue remodelling in physiological and pathological processes. There is enhanced expression of MMPs, in particular MMP-9, during numerous pathological conditions, including epilepsy and ischemic stroke. Therefore, inhibition of MMP-9 is considered as a potential therapeutic target. Tissue Inhibitor of Matrix Metalloproteinase-1 (TIMP-1) is a 28 kDa endogenous inhibitor of MMP-9. In this study we examined recombinant mouse TIMP-1 for its in-vitro neuroprotective effects, against Kainic Acid (KA) induced excitotoxicity in organotypic hippocampal slice culture (OHC) model. We also studied, sustained release effects of TIMP-1 in OHC by using poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs). TIMP-1 and TIMP-1 PLGA NPs were added to the slice cultures at different time points, i.e., 30 min before treatment with KA and 6 h after KA treatment. Propidium iodide staining was used to reveal cell toxicity in the cultures. In addition, neurotoxicity was assessed using standard lactate dehydrogenase (LDH) release assay. Gelatinolytic activity in conditioned cultured medium of OHC was accessed by a fluorescent substrate assay. Briefly, our result show that TIMP-1 provided significant level of neuroprotection, especially when given before 30 min of KA and released from the NPs. Since gelatinolytic activity assay showed a decrease in MMP-9 activity, it can be suggested that this neuroprotection might be mediated by the gelatinase inhibition.     

羌活地黄汤对大鼠佐剂性关节炎软骨金属蛋白酶-1、13及基质金属蛋白酶抑制剂-1的影响

目的：观察羌活地黄汤对大鼠佐剂性关节炎软骨中基质金属蛋白酶-1（marxmetalloproteinase-1,MMP-1）、基质金属蛋白酶-13（matrixmetalloproteinase．13,MMP-13）及基质金属蛋白酶抑制剂-1（tissueinhibitorofmetalloprotease-1,TIMP-1）表达的影响。方法：Wistar大鼠32只,随机分为正常对照组、模型组、雷公藤对照组、羌活地黄汤组。制作大鼠佐剂性关节炎模型,造模第14天开始给药。羌活地黄汤组予混有羌活地黄汤的颗粒饲料,雷公藤组给予混有雷公藤多甙的饲料,正常组及模型组均给予普通饲料。第28天分别取各组胫骨平台关节软骨,采用免疫组织化学染色测定软骨中MMP-1、13及T1MP—1表达的阳性指数。结果：模型组MMP-1、MMP-13及TIMP—1表达的阳性指数水平明显高于正常组,差异有统计学意义（P〈0．01）,羌活地黄汤组MMP-1、13及TIMP-1表达阳性指数低于模型组,差异有统计学意义（P〈0．05）。结论：羌活地黄汤可能是通过调控软骨细胞外基质中MMP．1、MMP—13及TIMP-1表达变化而维持软骨的动态平衡,从而延缓RA骨骼破坏。     

脑出血大鼠血肿周围脑组织含水量与MMP-9、IL-6及TIMP-1表达水平的相关性研究

目的:研究脑出血(ICH)大鼠血肿周围脑组织含水量与基质金属蛋白酶-9(MMP-9)、白细胞介素-6(IL-6)及组织基质金属蛋白酶抑制剂-1(TIMP-1)表达水平的相关性。方法:84只健康成年雄性Wistar大鼠按随机数字表法分成观察组、假手术组以及对照组,每组28只。另将观察组分成ICH后1d亚组9只,3d亚组9只,7d亚组10只。观察组大鼠实施ICH模型的制备,假手术组的大鼠仅给予空针穿刺,对照组不进行模型制备。检测并对比各组血肿周围的脑组织含水量与MMP-9、IL-6、TIMP-1水平,对比观察组内不同亚组(ICH后1d、3d、7d)血肿周围的脑组织含水量、MMP-9、IL-6和TIMP-1水平,并分析ICH大鼠血肿周围的脑组织含水量与MMP-9、IL-6、TIMP-1表达水平的相关性。结果:观察组血肿周围的脑组织含水量与MMP-9、IL-6、TIMP-1水平均分别高于假手术组及对照组,差异均有统计学意义(P0.05)。观察组内3d和7d亚组血肿周围的脑组织含水量与MMP-9、IL-6、TIMP-1水平均分别高于1d亚组,但7d亚组低于3d亚组,差异均有统计学意义(P0.05)。根据Spearman相关性分析结果显示,ICH大鼠血肿周围的脑组织含水量与MMP-9、IL-6、TIMP-1表达水平均呈正相关(P0.05)。结论:ICH大鼠的血肿周围脑组织含水量与MMP-9、IL-6及TIMP-1表达水平均呈正相关,MMP-9、IL-6、TIMP-1在ICH后周围组织水肿的发生、发展中具有重要作用。     

TIMP-1 stimulates proliferation of human aortic smooth muscle cells and Ras effector pathways

Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a multifunctional protein, which is found in most tissues and body fluids. Here, we demonstrated that recombinant TIMP-1 but not the synthetic matrix metalloproteinase inhibitor, GM6001, stimulated proliferation of human aortic smooth muscle cells (AoSMC) in a dose-dependent manner. The mitogenic effect was associated with activation of Ras, increased phosphorylation of ERK, and stimulation of cyclin D1 expression. The phosphatidylinositol 3-kinase (PI3K) signaling pathway was also involved since the PI3K inhibitor, LY294002, abolished the TIMP-1-mediated growth stimulation. These data suggest that TIMP-1 activates Ras, which then turns on the ERK and PI3K signaling pathways to promote cell cycle progression of the AoSMC.     

Intra and extravascular transmembrane signalling of angiopoietin-1-Tie2 receptor in health and disease

Angiopoietin-1 (Ang-1) is the primary agonist for Tie2 tyrosine kinase receptor (Tie2), and the effect of Ang-1-Tie2 signalling is context-dependent. Deficiency in either Ang-1 or Tie2 protein leads to severe microvascular defects and subsequent embryonic lethality in murine model. Tie2 receptors are expressed in several cell types, including endothelial cells, smooth muscle cells, fibroblasts, epithelial cells, monocytes, neutrophils, eosinophils and glial cells. Ang-1-Tie2 signalling induces a chemotactic effect in smooth muscle cells, neutrophils and eosinophils, and induces differentiation of mesenchymal cells to smooth muscle cells. Additionally, this signalling pathway induces the secretion of serotonin, matrix metalloproteinases (MMPs) and plasmin. Ang-1 inhibits the secretion of tissue inhibitor of matrix metalloproteinase (TIMPs). Aberrant expression and activity of Tie2 in vascular and non-vascular cells may result in the development of rheumatoid arthritis, cancer, hypertension and psoriasis. Ang-1 has an anti-inflammatory effect, when co-localized with vascular endothelial growth factor (VEGF) in the vasculature. Thus, Ang-1 could be potentially important in the therapy of various pathological conditions such as pulmonary hypertension, arteriosclerosis and diabetic retinopathy. In this article, we have summarized and critically reviewed the pathophysiological role of Ang-1-Tie2 signalling pathway.     

Role of membrane-associated CA2+ dependent matrix metalloprotease-2 in the oxidant activation of Ca2+ATPase by tertiary butylhydroperoxide

Treatment of bovine pulmonary artery smooth muscle plasma membrane suspension with the oxidant tert-butylhydroperoxide (t-buOOH) increases Ca²⁺⁺ATPase activity. The smooth muscle plasma membrane possesses a Ca²⁺⁺ dependent protease activity in the gelatin containing zymogram having an apparent molecular mass of 72 kDa. The 72 kDa protease activity was found to be inhibited by EGTA and the tissue inhibitor of metalloprotease-2 (TIMP-2). Since 72 kDa is the molecular mass of MMP-2 and since in our present study the 72 kDa protease in the gelatin containing zymogram is inhibited by matrix metalloprotease inhibitors, EGTA and TIMP-2, it may be suggested that the 72 kDa protease is the MMP-2. In addition to the increasing Ca²⁺⁺ATPase activity, t-buOOH also enhances the activity of the membrane associated Ca²⁺⁺ dependent protease that degrades ¹⁴C-gelatin. The oxidant triggered protease activity and the Ca²⁺⁺ATPase activity were found to be prevented by the antioxidant vitamin E, and also by the Ca²⁺⁺ dependent matrix metalloprotease inhibitors: EGTA and TIMP-2. Adding MMP-2 to the smooth muscle plasma membrane suspension caused an increase in Ca²⁺⁺ATPase activity and pretreatment with TIMP-2 prevents the increase in Ca²⁺⁺ATPase activity. Combined treatment of the smooth muscle plasma membrane with low doses of MMP-2 and t-buOOH augments further the Ca²⁺⁺ATPase activity caused by the respective doses of either t-buOOH or MMP-2. Pretreatment with TIMP-2 prevents the increase in Ca²⁺⁺ATPase activity elicited by the low doses of MMP-2 and/or t-buOOH.     

Role of Ca2+-dependent metalloprotease-2 in stimulating Ca2+ ATPase activity under peroxynitrite treatment in bovine pulmonary artery smooth muscle membrane

We have determined effect of the oxidant peroxynitrite (ONOO-) on Ca2+-dependent matrix metalloprotease-2 (MMP-2) activity and the role of the protease on Ca2+ ATPase activity in bovine pulmonary vascular smooth muscle plasma membrane under ONOO- -triggered conditions. The smooth muscle plasma membrane possesses a 72-kDa protease activity in a gelatin-containing zymogram. The 72-kDa protease activity has been found to be inhibited by tissue inhibitor of metalloprotease-2 (TIMP-2), indicating that the protease is the matrix metalloprotease-2 (MMP-2). Treatment of the membrane suspension with ONOO- caused stimulation of the MMP-2 activity (as evidenced by 14C-gelatin degradation) and also increased Ca2+ ATPase activity. The ONOO- -triggered protease activity and the Ca2+ ATPase activity were found to be inhibited by the antioxidants: vitamin E, thiourea, and mannitol. Pretreatment with catalase and superoxide dismutase did not significantly alter ONOO- -stimulated MMP-2 activity and Ca2+ATPase activity, indicating that peroxide and superoxide are not present in appreciable amount in ONOO-. Under both basal and ONOO- triggered conditions, the MMP-2 activity and the Ca2+ ATPase activity were also inhibited by EGTA, 1:10-phenanthroline, and TIMP-2. However, the ONOO- -stimulated MMP-2 activity and the Ca2+ ATPase activity were found to be insensitive to phenylmethylsulfonylfluoride, Bowman-Birk inhibitor, chymostatin, leupeptin, antipain, N-ethylmaleimide, and pepstatin. These results suggest that ONOO- caused stimulation of MMP-2 activity and that the increased MMP-2 activity subsequently played a pivotal role in stimulating Ca2+ ATPase activity in bovine pulmonary vascular smooth muscle plasma membrane.     

慢性肾小球肾炎患者血清MMP-9和TIMP-1的浓度及意义

目的:观察慢性肾小球肾炎血清基质金属蛋白酶9(matrix metalo protein-ase-9,MMP-9)、金属蛋白酶组织抑制剂1(tissue inhibitors of metalloproteinases,TIMP-1)的浓度与肾组织中MMP-9、TIMP-1表达的相关性,探讨慢性肾小球肾炎血清MMP-9、TIMP-1对肾脏纤维化的判断价值。方法:通过肾组织活检病理检查,将入选慢性肾炎的病例分增生组(A组)15例,纤维化组(B组)15例,另选10例志愿者作为健康对照组C组。应用免疫组化法观察A、B两组MMP-9、TIMP-1在肾组织中的表达情况,并且进行半定量分析,比较它们之间有无差别。应用ELISA双抗体夹心法检测A、B、C三组MMP-9、TIMP-1在血清中的浓度,比较它们之间有无差别。观察A、B两组MMP-9、TIMP-1在肾组织中的表达水平与在血清的浓度有无相关性。结果:A、B两组MMP-9在肾小球和肾间质少见表达,主要在肾小管上皮细胞浆中表达增高,两组之间表达的强度有显著差异性;A组TIMP-1在肾小球中少见表达,在肾小管上皮细胞增强。B组TIMP-1在肾小球中有少量表达,在肾小管上皮细胞较A组进一步增强,两组之间表达的强度有显著差异性(P0.05)。血清中MMP-9、TIMP-1浓度在A、B组显著高于C组,血清中MMP-9在A、B两组之间无显著差异性,血清中TIMP-1在A、B、C三组间两两比较有显著差别(P0.05)。结论:慢性肾炎患者血清中MMP-9、TIMP-1浓度与肾脏组织中MMP-9、TIMP-1的表达呈正相关。MMP-9、TIMP-1的相关性分析P值小于0.01。血清MMP-9、TIMP-1参与了肾脏纤维化的进展,慢性肾小球肾炎血清中MMP-9、TIMP-1的浓度可在一定程度上反映肾脏纤维化程度。     

Decreased Expression of Matrix Metalloproteinase-9 and Increased Expression of Tissue Inhibitors of Matrix Metalloproteinase-1 in Paratuberculosis-Infected Cattle in the ELISA-Negative Subclinical Stage

We investigated the gene expression of matrix metalloproteinases-9 (MMP-9) and tissue inhibitors of matrix metalloproteinases-1 (TIMP-1) in peripheral blood cells from infected cattle with Mycobacterium avium subsp. paratuberculosis (Map) in the ELISA-negative subclinical stage compared with uninfected control cattle. Significant decreased MMP-9 expression and increased TIMP-1 expression were found in peripheral blood cells from Map-infected cattle after stimulation with Map lysate and Map purified protein derivative (PPD) than in control cattle by real-time RT-PCR analysis. In contrast to the uninfected controls, the activity of MMP-9 was also decreased in peripheral blood cell culture supernatants from Map-infected cattle at 24 hr after Map lysate and MapPPD stimulation by gelatin zymography analysis. As a result, the MMP-9 may play an important role in the development of Mycobacterium avium subsp. paratuberculosis disease.     

Selective involvement of TIMP-2 in the second activational cleavage of pro-MMP-2: refinement of the pro-MMP-2 activation mechanism

A tissue inhibitor of metalloproteinases-2 (TIMP-2)-independent mechanism for generating the first activational cleavage of pro-matrix metalloproteinase-2 (MMP-2) was identified in membrane type-1 MMP (MT1-MMP)-transfected MCF-7 cells and confirmed in TIMP-2-deficient fibroblasts. In contrast, the second MMP-2-activational step was found to be TIMP-2 dependent in both systems. MMP-2 hemopexin C-terminal domain was found to be critical for the first step processing, confirming a need for membrane tethering. We propose that the intermediate species of MMP-2 forms the well-established trimolecular complex (MT1-MMP/TIMP-2/MMP-2) for further TIMP-2-dependent autocatalytic cleavage to the fully active species. This alternate mechanism may supplement the traditional TIMP-2-mediated first step mechanism.