Involvement of tissue inhibitors of metalloproteinases (TIMPS) during matrix metalloproteinase activation

Can EGCG Alleviate Symptoms of Down Syndrome by Altering Proteolytic Activity?

Down syndrome (DS), also known as "trisomy 21", is a genetic disorder caused by the presence of all or part of a third copy of chromosome 21. Silencing these extra genes is beyond existing technology and seems to be impractical. A number of pharmacologic options have been proposed to change the quality of life and lifespan of individuals with DS. It was reported that treatment with epigallocatechin gallate (EGCG) improves cognitive performance in animal models and in humans, suggesting that EGCG may alleviate symptoms of DS. Traditionally, EGCG has been associated with the ability to reduce dual specificity tyrosine phosphorylation regulated kinase 1A activity, which is overexpressed in trisomy 21. Based on the data available in the literature, we propose an additional way in which EGCG might affect trisomy 21-namely by modifying the proteolytic activity of the enzymes involved. It is known that, in Down syndrome, the nerve growth factor (NGF) metabolic pathway is altered: first by downregulating tissue plasminogen activator (tPA) that activates plasminogen to plasmin, an enzyme converting proNGF to mature NGF; secondly, overexpression of metalloproteinase 9 (MMP-9) further degrades NGF, lowering the amount of mature NGF. EGCG inhibits MMP-9, thus protecting NGF. Urokinase (uPA) and tPA are activators of plasminogen, and uPA is inhibited by EGCG, but regardless of their structural similarity tPA is not inhibited. In this review, we describe mechanisms of proteolytic enzymes (MMP-9 and plasminogen activation system), their role in Down syndrome, their inhibition by EGCG, possible degradation of this polyphenol and the ability of EGCG and its degradation products to cross the blood-brain barrier. We conclude that known data accumulated so far provide promising evidence of MMP-9 inhibition by EGCG in the brain, which could slow down the abnormal degradation of NGF.

Lymphangiogenesis and lymphatic remodeling induced by filarial parasites: implications for pathogenesis

Even in the absence of an adaptive immune system in murine models, lymphatic dilatation and dysfunction occur in filarial infections, although severe irreversible lymphedema and elephantiasis appears to require an intact adaptive immune response in human infections. To address how filarial parasites and their antigens influence the lymphatics directly, human lymphatic endothelial cells were exposed to filarial antigens, live parasites, or infected patient serum. Live filarial parasites or filarial antigens induced both significant LEC proliferation and differentiation into tube-like structures in vitro. Moreover, serum from patently infected (microfilaria positive) patients and those with longstanding chronic lymphatic obstruction induced significantly increased LEC proliferation compared to sera from uninfected individuals. Differentiation of LEC into tube-like networks was found to be associated with significantly increased levels of matrix metalloproteases and inhibition of their TIMP inhibitors (Tissue inhibitors of matrix metalloproteases). Comparison of global gene expression induced by live parasites in LEC to parasite-unexposed LEC demonstrated that filarial parasites altered the expression of those genes involved in cellular organization and development as well as those associated with junction adherence pathways that in turn decreased trans-endothelial transport as assessed by FITC-Dextran. The data suggest that filarial parasites directly induce lymphangiogenesis and lymphatic differentiation and provide insight into the mechanisms underlying the pathology seen in lymphatic filariasis.

The nematode parasites Brugia malayi and Wuchereria bancrofti are the major organisms responsible for lymphatic filariasis. Lymphatic filariasis is characterized by the dysfunction of the lymphatics that can lead to severe (and often) irreversible lymphedema and elephantiasis. Current advances in distinguishing blood vascular from lymphatic endothelial cells have allowed the direct study of the interaction between live filarial parasites and their lymphatic niche. In the quest towards understanding parasite-lymphatic endothelium interactions, we observed that the filarial antigens have a specific but differential stimulatory capacity towards the lymphatics and cause them to differentiate into tube-like vascular networks in vitro that resemble the formation of collateral lymphatics in vivo. This was a lymphatic-specific phenomenon, as the filarial parasites or antigen did not exhibit similar effects on the human umbilical vein endothelial cells. The differentiation of the lymphatic endothelial monolayers into vascular networks was not dependent on typical markers of lymphangiogenesis but rather involves the matrix metalloproteases and their inhibitors that suggest lymphatic matrix remodeling rather than rendering of the lymphatics hyper-permeable as has been postulated previously.

Relations of matrix remodeling biomarkers to blood pressure progression and incidence of hypertension in the community

BACKGROUND

Biomarkers of extracellular matrix remodeling are associated with prevalent hypertension in cross-sectional studies, but their relations to longitudinal changes in blood pressure (BP) and hypertension incidence are unknown.

METHODS AND RESULTS

We evaluated 595 nonhypertensive Framingham Offspring Study participants (mean age 55 years; 360 women) without prior heart failure or myocardial infarction who underwent routine measurements of plasma tissue inhibitor of metalloproteinase-1 (TIMP-1), metalloproteinase-9 (MMP-9), and procollagen III N-terminal peptide. We related plasma TIMP-1, procollagen III N-terminal peptide, and MMP-9 to the incidence of hypertension and progression of BP by >or=1 category (defined on the basis of the sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure). On follow-up (4 years), 81 participants (51 women) developed hypertension, and 198 (114 women) progressed to a higher BP category. In multivariable models, a 1-SD increment of log-TIMP-1 was associated with a 50% higher incidence of hypertension (95% CI 1.08 to 2.08) and a 21% (95% CI 1.00 to 1.47) higher risk of BP progression. Individuals in the top TIMP-1 tertile had a 2.15-fold increased risk of hypertension (95% CI 0.99 to 4.68) and 1.68-fold (95% CI 1.05 to 2.70) increased risk of BP progression relative to the lowest tertile. Individuals with detectable MMP-9 had a 1.97-fold higher risk of BP progression (95% CI 1.06 to 3.64) than those with undetectable levels. Plasma procollagen III N-terminal peptide was not associated with hypertension incidence or BP progression.

CONCLUSIONS

In the present community-based sample, higher TIMP-1 and MMP-9 concentrations were associated with BP progression on follow-up. Additional studies are warranted to confirm our findings.

Noninvasive diagnosis of bladder cancer by detection of matrix metalloproteinases (MMP-2 and MMP-9) and their inhibitor (TIMP-2) in urine

OBJECTIVES

TIMPs control the activity of MMPs, one of the key molecules for tumor invasion and metastasis. The aim of this study was to assess the usefulness of MMP-2 and MMP-9 in relation to their inhibitor (TIMP2) as noninvasive diagnostic tests for bilharzial bladder cancer.

MATERIAL AND METHODS

Voided urine samples were provided from 244 subjects (154 bladder cancer [136 bilharzial]; 60 benign urologic disorders; 30 healthy volunteers). Urine sediment was used for cytology, and the supernatant for estimation of MMPs and TIMP-2 by ELISA and gelatin zymography.

RESULTS

The best cut-off values for the investigated markers were determined by ROC curve. Positivity rates and median levels for MMP-2, MMP-9, TIMP-2, MMP-2/TIMP-2, and MMP-9/TIMP-2 showed significant difference among the three investigated groups (p<0.001). MMP-9 and MMP-2/TIMP-2 were related to pathologic type, MMP-2/TIMP-2 was inversely related to the grade, and MMP-9/TIMP-2 was related to bilharziasis (p<0.05). MMP zymography results were comparable to those from ELISA.

CONCLUSION

The sensitivity and specificity of MMP zymography, MMP-9/TIMP-2 ratio, and MMP-2/TIMP2 ratio were superior among all investigated parameters; furthermore, combined testing of cytology with them improves the sensitivity even in superficial and low-grade tumors.

Stretch-induced modulation of matrix metalloproteinases in mineralizing osteoblasts via extracellular signal-regulated kinase-1/2

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) produced by osteoblasts play an essential role in bone remodeling. Hence, these proteins could provide an interesting means by which mechanical loading leads to adaptation of bone. Here, we examined the effect of stretch on MMP-1, -2, -3, -8, -9, -13, and -14, as well as TIMP-1 and -2 gene expression in differentiating, mineralizing, and nonmineralizing human SV-40 immortalized preosteoblast cells. In the mineralizing osteoblast culture, but not in the nonmineralizing cultures, cyclic stretch for only 15 min resulted in an increase of MMP-1 (fourfold) and -3 (depending on differentiation stage up to 25-fold) transcript abundance. No clear effect was observed for other MMPs, TIMP-1 or -2. The increase of MMP-1 and -3 was confirmed on the protein level. Stretching experiments performed in the presence of a specific inhibitor of extracellular signal-regulated kinase (ERK) showed a strong suppression of the stretch-induced increase in MMP-1 and -3. In conclusion, we show that MMP-1 and MMP-3 are mechanosensitive genes in mineralizing the human osteoblast, and that the mechano-induction of these genes is mediated via the ERK pathway. Our findings implicate that these MMPs are important factors in the mechanoregulation of bone turnover. With the ability to generate MMPs at highly stretched sites, osteoblasts can potantially direct osteoclasts to specific bone surface areas prepared for resorption.

Effect of recombinant human tissue inhibitor of matrix metalloproteinase-1 in rabbit mandibular distraction osteogenesis: A histological and immunohistochemical study

BACKGROUND

Bone matrix metalloproteinases are capable of degrading bone matrix during the remodelling, and their degradation activities can be down regulated by the tissue inhibitors of matrix metalloproteinases. This study evaluated the influence of exogenous tissue inhibitor of matrix metalloproteinase-1 on the expression of matrix metalloproteinases and endogenous tissue inhibitor of matrix metalloproteinases in mandibular distraction osteogenesis.

MATERIAL AND METHODS

Fifteen New Zealand white rabbits were assigned to three groups: a negative control; a sham control group implanted with a collagen sheet; and an experimental group implanted with recombinant human tissue inhibitor of matrix metalloproteinase-1 impregnated in a collagen sheet. Rabbits were sacrificed at 6 weeks, 12 weeks and 24 weeks of consolidation.

RESULTS

Major expression of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases was observed at the early stage of consolidation, only positive signals of tissue inhibitors of matrix metalloproteinases were observed at 24 weeks. The addition of recombinant human tissue inhibitor of matrix metalloproteinases-1 did not affect bone maturation and remodelling.

CONCLUSIONS

An equilibrium of bone formation and resorption was reached at 24 weeks of consolidation in the rabbit mandible. No obvious influence of recombinant human tissue inhibitor of matrix metalloproteinase-1 on bone remodelling of mandibular distraction osteogenesis was noted.

Porphyromonas gingivalis affects host collagen degradation by affecting expression, activation, and inhibition of matrix metalloproteinases

OBJECTIVE

Studies have shown that Porphyromonas gingivalis and host matrix metalloproteinases (MMPs) play important roles in the tissue destruction associated with periodontal disease. It is still unclear which MMPs or their inhibitors are regulated by P. gingivalis at the transcriptional and/or at the protein levels. Therefore, this study was conducted to determine what effects P. gingivalis supernatant has on the collagen degrading ability of human gingival fibroblasts (HGFs) and how it regulates the activation, mRNA expression, and inhibition of MMPs.

METHODS

Culture supernatant from P. gingivalis ATCC 33277 was added to HGFs cultured in six-well plates coated with Type I collagen. At certain time intervals, the cell conditioned media was collected for zymography and/or western blot analyses to determine the MMP and tissue inhibitor of MMPs (TIMP) protein levels. The cells were then removed and the collagen cleavage visualized by Coomassie blue staining. The mRNA expression of multiple MMPs and TIMPs by the treated and untreated HGFs was determined by reverse transcription-polymerase chain reaction.

RESULTS

The collagen in the six-well plates was degraded more rapidly by the HGFs treated with 10% v/v P. gingivalis supernatant. More active MMP-1, MMP-2, MMP-3, and MMP-14 were detected in the conditioned media from the HGFs treated with the P. gingivalis supernatant. TIMP-1, but not TIMP-2, was decreased in the presence of the P. gingivalis supernatant. MMP-1 mRNA expression by the treated HGFs increased more than two-fold over the untreated HGFs. MMP-3 mRNA was unchanged, MMP-2 mRNA had a slight increase, MMP-14 mRNA decreased, and MMP-15 increased. MMP-12 mRNA was induced in the P. gingivalis treated HGFs. TIMP-1 and TIMP-2 mRNA had a slight increase with P. gingivalis treatment.

CONCLUSION

Porphyromonas gingivalis increased the collagen degrading ability of HGFs, in part, by increasing MMP activation and by lowering the TIMP-1 protein level, as well as by affecting the mRNA expression of multiple MMPs and TIMPs.

Matrix metalloproteinase inhibitor RECK expression in canine tumors

Matrix metalloproteinases (MMPs) selectively degrade the extracellular matrix, and they have been reported to play an important role in tumor invasion, metastasis and angiogenesis. These enzymes are closely related to tumor malignancy and patient survival time. Recently, reversion-inducing cysteine-rich protein with Kazal motifs (RECK) gene was identified as an endogenous membrane-anchored MMP inhibitor. The down-regulation of RECK has been implicated in tumor progression. In this study, the expression levels of the RECK messenger ribonucleic acid (mRNA) in various spontaneously developed canine tumors were investigated by using quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), and the correlation between RECK and clinicopathological factors, as well as MMP-9 expression were analyzed. The median age of 36 dogs investigated in this study was 9 years old (range, 1-15 years old). Quantitative RT-PCR could detect low levels of expression of RECK mRNA in the tumor samples. The expression levels of RECK mRNA in some tumor tissue samples were significantly lower than those in normal tissue samples. No significant associations of RECK with clinicopathological factors were observed. Using the Mann-Whitney U test, the expression level of the MMP-9 mRNA was observed to be significantly correlated to RECK expression (p<0.05).

Prognostic value of tissue inhibitor of metalloproteinase-1 for cardiovascular death among patients with cardiovascular disease: results from the AtheroGene study

AIMS

Metalloproteinases are proteolytic enzymes, which decompose the extracellular matrix, influence cardiac remodelling, and are inhibited by tissue inhibitor of metalloproteinases (TIMPs). Little is known about the prognostic impact of the TIMP-1/matrix metalloproteinase complex in patients with future cardiovascular death.

METHODS AND RESULTS

In 1979 patients with suspected coronary artery disease (CAD), TIMP-1 has been determined at baseline. Among 1945 (98.4%) patients with a mean follow-up period of 2.6+/-1.2 years, 75 patients died because of cardiovascular causes. Mean concentrations of TIMP-1 were higher among patients who experienced a fatal cardiovascular event than among those who did not (820 vs. 692 ng/mL; P<0.001). Age and sex adjusted hazard ratio of future cardiovascular death associated with one standard deviation of TIMP-1 level, was 1.37 (95% CI: 1.17-1.61; P<0.001). The hazard ratio remained nearly identical after adjustment for clinical and therapeutic confounders. B-type natriuretic peptide (2.75, 95% CI: 1.94-3.89; P<0.001), C-reactive protein (1.79, 95% CI: 1.43-2.24; P<0.001), and TIMP-1 (1.30, 95% CI: 1.07-1.58; P=0.008) were independently associated with future cardiovascular death.

CONCLUSION

In patients with CAD, TIMP-1 proves as an independent predictor for future cardiovascular death.

The emerging role of proteases in retinal ganglion cell death

Retinal ganglion cell (RGC) death is an important issue in Primary Open Angle-Glaucoma (POAG) in terms of both vision loss and health care costs. Yet, the pathophysiology underlying RGC death in glaucoma is unclear. A growing body of evidence indicates that proteases that modulate the extracellular matrix (ECM) milieu in the retina, either directly or indirectly, play an important role in dictating the fate of RGCs. Recent evidence indicates that proteases, in addition to ECM-remodeling, have broader functional roles in glutamate receptor processing and predisposing RGCs to secondary damage. This review is focused on discussing the role of two groups of proteases, the matrix metalloproteinases (MMPs) and the plasminogen activators (PAs), in RGC death. In a long-run, a better understanding of the mechanisms involved in the regulation of proteases may lead to the development of adjunctive treatment options to attenuate RGC death and improve vision loss in glaucoma.

Intravitreous injection of a membrane depolarization agent causes retinal degeneration via matrix metalloproteinase-9

PURPOSE

Membrane depolarization and subsequent synaptic release of l-glutamate have been implicated in ischemic retinal damage. However, the mechanisms that lead to ischemia-induced retinal damage are poorly understood. In this study, KCl, a classic membrane depolarizing agent, was injected into the vitreous humor, and the role of matrix metalloproteinase (MMP)-9 in KCl-induced retinal damage was investigated.

METHODS

Normal adult CD-1 mice were treated with KCl by intravitreal injection. MMP activity in retinal protein extracts was determined by gelatin zymography. Tissue localization of MMP-9 in the retina was determined by immunohistochemistry. MMP-9, MMP-2, tissue inhibitor of MMP (TIMP)-1, TIMP-2, Bax, and BCl-2 proteins in retinal extracts were determined by Western blot analysis. Apoptotic cell death in the retina was determined by TUNEL assays. Retinal damage was assessed by immunolocalization studies with antibodies against neurofilament-light (NF-L) and calretinin.

RESULTS

Depolarizing concentrations of KCl induced a dose- and time-related upregulation in MMP-9 activity and protein in the retina. KCl-mediated MMP-9 upregulation was associated with an increase in proapoptotic protein Bax and apoptotic death of cells in the ganglion cell (GCL) and inner nuclear layer (INL), and subsequent loss of NF-L-positive ganglion cells and calretinin-positive amacrine cells. Intravitreal injection of KCl along with an N-methyl-d-aspartate (NMDA)-type glutamate receptor antagonist, MK-801, and a non-NMDA-type glutamate receptor antagonist, NBQX, resulted in a reduction in KCl-mediated MMP-9 upregulation in the retina. Furthermore, a synthetic MMP inhibitor inhibited KCl-mediated MMP-9 upregulation, which led to a significant attenuation of KCl-induced retinal damage.

CONCLUSIONS

These results suggest that upregulation of MMP-9, in part, plays a causative role in KCl-induced retinal damage.

Limited processing of pro-matrix metalloprotease-2 (gelatinase A) overexpressed by transfection in PC-3 human prostate tumor cells: association with restricted cell surface localization of membrane-type matrix metalloproteinase-1

The expression and activation of matrix metalloproteinases (MMPs) by tumor cells is correlated with progression to invasive and metastatic status. The purpose of this study was to examine the role of increased MMP-2 (gelatinase A) expression in prostate cancer progression utilizing human prostate PC-3 cancer cells that overexpress MMP-2 using gene transfection. PC-3 cells were transfected with pCR-3 vector only and pCR-3 MMP-2 plasmids employing the LipofectAMINE method, and stable transfectants were selected with G418. The expression of MMP-2, tissue inhibitor of metalloproteinase-2 (TIMP-2), and membrane-type MMP 1 (MT1-MMP) in PC-3 parental and transfected cells under serum-free conditions was determined by zymography, immunoblotting, immunofluorescent microscopy, Northern blotting, and/or reverse transcriptase-polymerase chain reaction (RT-PCR). MMP-2 transfected cells produced primarily the proenzyme form of MMP-2; the parental and vector control transfected PC-3 cells did not express any MMP-2 that was detectable by the methods we employed. Treatment of PC-3 MMP-2 transfected cells with Concanavalin A (Con A), in contrast to HT-1080 cells, processed only a small amount of the secreted 72-kd proenzyme to a 62-kd intermediate and a cell-associated 59-kd active form. The low level of secreted pro-MMP-2 processing induced by Con A was inhibited by serine protease inhibitors and was unaffected by cyclic adenosine monophosphate (cAMP). Immunoblotting showed that these cells produced abundant TIMP-2 and lower amounts of MT1-MMP in comparison with Con A-responding HT-1080 cells. HT-1080 cells respond to Con A by translocating MT1-MMP from intracellular localization sites to the plasma membrane, an effect not observed in PC-3 cells. The molecular basis for the low level of processing of pro-MMP-2 by PC-3 cells may be due to an overabundance of TIMP-2 and/or a low level of cell surface active MT1-MMP.

Matrix metalloproteinases in the pathogenesis of estradiol-induced nonbacterial prostatitis in the lateral prostate lobe of the Wistar rat

Chronic nonbacterial prostatitis develops spontaneously with age in the lateral lobe of the prostate in some strains of rat. Our objective was to examine the role of matrix metalloproteinases (MMP) in the pathogenesis of chronic nonbacterial prostatitis using a chronic estrogen treatment, Wistar rat model (Prostate 12 (1988) 271). Male Wistar rats, 90 days of age (8 rats/group), were castrated and groups were implanted 8 days later with 1 cm silastic tubings containing estradiol 17 beta (E2). Some animals received 5-cm silastic tubings of dihydrotestosterone (DHT) or testosterone (T) on day 22 and all untreated control and experimental animals were sacrificed on day 36 of the protocol. MMP activities were determined by SDS-gelatin-, casein-, and carboxymethyl transferrin-polyacrylamide gel zymography. A light/mild interstitial monocytic infiltration was found in the ventral lobes, but not other lobes, of half of the untreated control rats. This ventral lobe interstitial inflammation was not affected by E2 treatment. A prominent to heavy inflammation, including both intraluminal neutrophil and interstitial monocytic infiltrates, was produced by E2 treatment at a 100% incidence in the lateral lobes. Prominent MMP activities were detected in the lateral lobes of E2-treated rats, including both the active (55 and 81 kDa) and proenzyme (72 and 92 kDa) forms of MMP-2 and MMP-9, respectively. These activities were strongly attenuated by treatment of E2-implanted animals with T, which also reduced inflammation; but they were only weakly affected by DHT given with E2, which did not reduce inflammation. Similarly, DHT treatment of E2-implanted castrated rats restored the wet weight of the lateral lobe, but it did not fully restore secretion volume production, whereas T treatment of estrogenized rats increased lateral lobe wet weight and secretion volume above that of untreated controls. E2 treatment also induced an activity in casein gels of about 27 kDa with properties of MMP-7; that is, molecular mass, inhibition by EDTA, stimulation by heparin sulfate in casein and carboxymethylated transferrin gels. A high molecular weight nonmetalloproteinase activity (>160 kDa) was detected in gelatin gels in the lateral prostate lobe of both treated and untreated control animals. In comparison to the lateral lobe, E2 treatment produced only minimal effects on MMP activities in the ventral and dorsal prostatic lobes. Thus, elevated MMP-2, MMP-7, and MMP-9 activities in lateral lobe prostatitis correlate with leukocyte infiltration in the inflammatory response. These proteinases may help mediate the accompanying epithelial atrophy and tissue damage in this organ.

Matrix metalloproteinase inhibitor reversion-inducing cysteine-rich protein with Kazal motifs: a prognostic marker for good clinical outcome in human breast carcinoma

BACKGROUND

The recently described reversion-inducing cysteine-rich protein with Kazal motifs (RECK) inhibits membrane Type 1 matrix metalloproteinase (MMP-14), MMP-2, and MMP-9 secretion and enzymatic activity. Its expression is essential for normal vasculogenesis. Down-regulation of RECK has been implicated in tumor angiogenesis and progression.

METHODS

The authors assessed the prognostic value of RECK expression in tumor tissue specimens from 278 breast carcinoma patients with a median follow-up time of 75 months (range, 2-169 months). RECK mRNA levels were measured by real-time quantitative reverse transcriptase-polymerase chain reaction.

RESULTS

Expression levels of RECK were lower in tumor tissue specimens than in adjacent normal breast tissue specimens from 10 patients (P = 0.028). No relevant associations of RECK with established clinicopathologic factors or treatment regimens were found. RECK expression predicted a longer recurrence-free survival time (RFS; P = 0.037) at the optimal cutoff value (hazard ratio, 0.66; 95% confidence interval, 0.44-0.98). The 100 patients whose tumors exhibited low levels of RECK had a mean RFS time of 80.4 months and a 61.8% 5-year RFS rate, whereas the 178 patients with tumors with high RECK expression had a mean RFS time of 91.2 months and a 73.0% 5-year RFS rate. Multivariate Cox regression analysis showed that RECK expression maintained a significant independent prognostic value for RFS time (P = 0.047).

CONCLUSIONS

These results are in agreement with the notion of RECK being an important tumor-suppressor gene. Therefore, the possibility of applying RECK, a pharmaceutical mimetic, or drugs activating endogenous RECK expression, as possible therapeutic or preventive agents for breast carcinoma should be explored.

Expression of matrix metalloproteinase-2 and -9 and their inhibitors, tissue inhibitor of metalloproteinase-1 and -2, in primary cultures of human prostatic stromal and epithelial cells

The production of matrix metalloproteinases (MMPs) by prostatic epithelial and/or neighboring stromal cells is considered to be a property that gives cells the capability to penetrate extracellular matrix barriers in normal or neoplastic growth. In order to examine the role of MMPs in the prostate, we evaluated the expression of MMP-2 and -9 and the tissue inhibitors of matrix metalloproteinases (TIMP)-1 and -2 in primary cultures of prostatic stromal and epithelial cells. These cells were isolated from normal tissues of the different zones of the prostate, from benign prostatic hyperplasia (BPH) and from cancer. Stromal cells, regardless of tissue of origin, secreted the 72-kDa proenzyme form of MMP-2, whereas conditioned media (CM) from epithelial cells demonstrated little/no pro-MMP-2 as examined by zymography. Either type of cell did not secrete MMP-9. RT-PCR evaluation showed stromal cells expressed transcripts for MMP-2, but not for MMP-9. Transcripts for MMP-9 were detected in epithelial cells, although no MMP-9 activity was detected in their CM. Treatment of stromal cells with 1 or 10 ng/ml of transforming growth factor-beta (TGF-beta) moderately increased secretion of pro-MMP-2 protein with little change in MMP-2 RNA. However, treatment of epithelial cells with TGF-beta induced expression and secretion of both MMP-2 and-9. The effect of TGF-beta on expression of MMPs by epithelial cells was not duplicated or affected by treatment with insulin-like growth factor (IGF)-1, epidermal growth factor (EGF), platelet-derived growth factor (PDGF), or basic fibroblast growth factor (bFGF). Stromal cells expressed transcripts of both TIMP-1 and -2. Epithelial cells expressed TIMP-1, but little TIMP-2. TGF-beta did not regulate the expression of TIMP-1 or -2 in either stromal or epithelial cells. Our results suggest that the elevated levels of MMP-2 and -9 observed in prostate development and cancer may be due to the elevated TGF-beta associated with these tissues.

A role for the 72 kDa gelatinase (MMP-2) and its inhibitor (TIMP-2) in human parturition, premature rupture of membranes and intraamniotic infection

OBJECTIVE

Degradation of the extracellular matrix in fetal membranes has been implicated in the process of parturition and rupture of membranes. Matrix metalloproteinases (MMPs) are enzymes capable of degrading extracellular matrix including collagen. Tissue inhibitors of matrix metalloproteinases (TIMPs) inhibit the activity of MMPs by covalently binding to the enzymes. MMP-2 degrades Type IV collagen and TIMP-2 is its specific inhibitor. The objective of this study was to determine if human parturition, rupture of membranes (term and preterm) and microbial invasion of the amniotic cavity (MIAC) are associated with changes in the concentrations of MMP-2 and TIMP-2 in amniotic fluid.

STUDY DESIGN

A cross-sectional study was conducted with women in the following categories: 1) term with intact membranes, in labor and not in labor; 2) preterm labor and intact membranes who delivered at term, who delivered preterm and preterm labor with MIAC; 3) preterm premature rupture of membranes (PROM) with and without infection; 4) term and preterm PROM not in labor; and 5) midtrimester. MMP-2 and TIMP-2 concentrations in amniotic fluid were determined using sensitive and specific immunoassays.

RESULTS

The concentration of TIMP-2 increased with advancing gestational age (r = 0.6, p < 0.001). No correlation was found between MMP-2 concentrations and gestational age. Human parturition and rupture of membranes (term and preterm) and in patients with intact membranes were not associated with changes in the amniotic fluid MMP-2 concentrations. In contrast, 1) patients with spontaneous labor (term and preterm) had significantly lower median concentrations of TIMP-2 compared to those not in labor (p < 0.05 for both); 2) MIAC in women with preterm labor and preterm PROM was associated with a significant decrease in amniotic fluid TIMP-2 concentrations (p < 0.04 for both comparisons); 3) Rupture of the membranes (term and preterm) was also associated with a significant decrease in the amniotic fluid TIMP-2 concentrations (p < 0.05 and p < 0.03, respectively).

CONCLUSIONS

Human parturition (preterm and term), rupture of fetal membranes (term and preterm) and intraamniotic infection are associated with a significant decrease in amniotic fluid TIMP-2 concentrations.

Remodeling of extracellular matrix in gastric ulceration

The quality of ulcer repair remains crucial for the stability of the injured tissue and for preventing recurrence. Therefore, we studied the temporo-spatial expression of the fibrillar and basement membrane collagens (types I, III, and IV), the collagenase MMP-2 as well as its inhibitor TIMP-1 before and after oral administration of basic fibroblast growth factor (b-FGF) over 30 days in acetic acid-induced rat gastric ulcers. The alterations and the exact location of the mRNA transcripts and their precipitated proteins were visualized by means of radioactive in situ hybridization and immunohistochemistry. Our data show that hybridization signals of procollagen I could first be identified 2 hours after ulcer induction. After 12 hours the ulcer was established and the mRNA was enhanced at the ulcer margin. After 24-48 hours the other procollagen transcripts were detected and all were further upregulated over the mesenchymal cells of all gastric layers up to 21 days, then declined at 30 days. In contrast, MMP-2 became prominent after 48 hours and up to 21 days. TIMP-1 was enhanced at 72 hours. After oral administration of b-FGF the transcriptional activity of the procollagens and MMP-2 was not significantly altered, while ulcer diameter was significantly reduced. We conclude that the early onset and long duration of collagens' expression points to their central structural and functional role in gastric ulcer healing. MMP-2 seems to be involved in both active ulceration and ECM remodeling. The timing of TIMP/MMP expression may be critical for proper restoration of gastric wall integrity.

Transcriptional induction of matrix metalloproteinase-13 (collagenase-3) by 1alpha,25-dihydroxyvitamin D3 in mouse osteoblastic MC3T3-E1 cells

The removal of unmineralized matrix from the bone surface is essential for the initiation of osteoclastic bone resorption because osteoclasts cannot attach to the unmineralized osteoid. Matrix metalloproteinases (MMPs) are known to digest bone matrix. We recently reported that among the MMPs expressed in mouse osteoblastic cells, MMP-13 (collagenase-3) was the one most predominantly up-regulated by bone resorbing factors including 1alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3]. In this study, we examined the mechanism of regulation of MMP-13 expression by 1alpha,25(OH)2D3 in mouse osteoblastic MC3T3-E1 cells. 1Alpha,25(OH)2D3 increased steady-state messenger RNA (mRNA) and protein levels of MMP-13. De novo protein synthesis was essential for the induction because cycloheximide (CHX) decreased the effect of 1alpha,25(OH)2D3 on the MMP-13 mRNA level. 1Alpha,25(OH)2D3 did not alter the decay of MMP-13 mRNA in transcriptionally arrested MC3T3-E1 cells; however, it increased the MMP-13 heterogeneous nuclear RNA (hnRNA) level and MMP-13 transcriptional rate. The binding activity of nuclear extracts to the AP-1 binding site, but not to the Cbfa1 binding site, in the MMP-13 promoter region was up-regulated by 1alpha,25(OH)2D3, suggesting the mediation of AP-1 in this transcriptional induction. To determine the contribution of MMPs to bone resorption by 1alpha,25(OH)2D3, the inhibitory effect of BB94, an MMP inhibitor, on resorbed pit formation by mouse crude osteoclastic cells was examined on either an uncoated or collagen-coated dentine slice. BB94 did not prevent resorbed pit formation on uncoated dentine whereas it did on collagen-coated dentine. We therefore propose that the transcriptional induction of MMP-13 in osteoblastic cells may contribute to the degradation of unmineralized matrix on the bone surface as an early step of bone resorption by 1alpha,25(OH)2D3.

Regulation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) by bone resorptive factors in osteoblastic cells

In addition to their stimulating function on osteoclastic bone resorption, bone resorptive factors may regulate proteinases and related factors in osteoblastic cells to degrade bone matrix proteins. This study investigated the regulation of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) by bone resorptive factors in the cultures of mouse osteoblastic MC3T3-E1 cells, mouse primary osteoblastic (POB) cells, and neonatal mouse calvariae. Expression of either MMP-2, -3, -9, -11, -13, and -14 or TIMP-1, -2, and -3 was detected in MC3T3-E1 cells and POB cells. When the bone resorptive factors parathyroid hormone, 1,25-dihydroxyvitamin D(3), prostaglandin E(2), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha) were added to the cell cultures, MMP-13 mRNA levels were found predominantly to increase by all resorptive factors in the three cultures. mRNA levels of either MMP-3 and -9 or TIMP-1 and -3 were found to increase mainly by the cytokines IL-1beta and TNF-alpha. BB94, a nonselective MMP inhibitor, neutralized the (45)Ca release stimulated by these resorptive factors to an extent similar to that of calcitonin, strongly suggesting that bone resorptive factors function at least partly through MMP formation. We propose that MMP-13 mRNA expression in osteoblastic cells may play an important role in stimulating matrix degradation by both systemic and local resorptive factors, whereas either MMP-3 and -9 or TIMP-1 and -3 might modulate matrix degradation by local cytokines only.

Matrix metalloproteinase inhibition. From the Jurassic to the third millennium

A brief historical introduction to the matrix metalloproteinase (MMP) field, which began in 1962, is followed by an overview of the inhibition of these proteases by natural inhibitors such as alpha 2 macroglobulin and the TIMPs (tissue inhibitors of metalloproteinases) and by synthetic inhibitors, which are largely chelating agents. The latter include thiol, alkylcarbonyl, phosponamidate and hydroxamate compounds, as well as the tetracyclines. A review of the most recent progress concludes with prognostications as to where the field may be going next.

Matrix metalloproteinases in cerebrovascular disease

Cerebral ischemia and intracerebral hemorrhage cause extensive damage to neurons, disrupt the extracellular matrix, and increase capillary permeability. Multiple substrates participate in the cellular damage, including free radicals and proteases. Matrix metalloproteinases and serine proteases are two classes of proteases that are normally present in brain in latent forms, but once activated, contribute to the injury process. These enzymes have a unique role in the remodeling of the extracellular matrix and in the modulation of the capillary permeability. Intracerebral injection of the matrix metalloproteinase, type IV collagenase, attacks the basal lamina around the capillary and opens the blood-brain barrier. Extracellular matrix-degrading proteases are induced by immediate early genes and cytokines, and regulated by growth factors. Activity of the matrix metalloproteinases is tightly controlled by activation mechanisms and tissue inhibitors of metalloproteinases. During ischemia and hemorrhage, multiple matrix metalloproteinases and serine proteases are produced along with their inhibitors. These proteolytic enzymes are involved in the delayed injury that accompanies the neuroinflammatory response. Synthetic inhibitors to metalloproteinases reduce proteolytic tissue damage, and may limit secondary neuroinflammation.

The cellular trafficking and zinc dependence of secretory and lysosomal sphingomyelinase, two products of the acid sphingomyelinase gene

The acid sphingomyelinase (ASM) gene, which has been implicated in ceramide-mediated cell signaling and atherogenesis, gives rise to both lysosomal SMase (L-SMase), which is reportedly cation-independent, and secretory SMase (S-SMase), which is fully or partially dependent on Zn2+ for enzymatic activity. Herein we present evidence for a model to explain how a single mRNA gives rise to two forms of SMase with different cellular trafficking and apparent differences in Zn2+ dependence. First, we show that both S-SMase and L-SMase, which contain several highly conserved zinc-binding motifs, are directly activated by zinc. In addition, SMase assayed from a lysosome-rich fraction of Chinese hamster ovary cells was found to be partially zinc-dependent, suggesting that intact lysosomes from these cells contain subsaturating levels of Zn2+. Analysis of Asn-linked oligosaccharides and of N-terminal amino acid sequence indicated that S-SMase arises by trafficking through the Golgi secretory pathway, not by cellular release of L-SMase during trafficking to lysosomes or after delivery to lysosomes. Most importantly, when Zn2+-dependent S-SMase was incubated with SMase-negative cells, the enzyme was internalized, trafficked to lysosomes, and became zinc-independent. We conclude that L-SMase is exposed to cellular Zn2+ during trafficking to lysosomes, in lysosomes, and/or during cell homogenization. In contrast, the pathway targeting S-SMase to secretion appears to be relatively sequestered from cellular pools of Zn2+; thus S-SMase requires exogeneous Zn2+ for full activity. This model provides important information for understanding the enzymology and regulation of L- and S-SMase and for exploring possible roles of ASM gene products in cell signaling and atherogenesis.

Preparation and characterization of recombinant tissue inhibitor of metalloproteinase 4 (TIMP-4)

TIMP-4, a novel human tissue inhibitor of metalloproteinase, was identified and cloned (Greene, J., Wang, M., Raymond, L. A., Liu, Y. E., Rosen, C., and Shi, Y. E. (1996) J. Biol. Chem. 271, 30375-30380). In this report, the production and characterization of recombinant TIMP-4 (rTIMP4p) are described. rTIMP4p, expressed in baculovirus-infected insect cells, was purified to homogeneity by a combination of cation exchange, hydrophobic, and size-exclusion chromatographies. The purified protein migrated as a single 23-kDa band in SDS-polyacrylamide gel electrophoresis and in Western blot using a specific anti-TIMP-4 antibody. Inhibition of matrix metalloproteinase (MMP) activities by rTIMP4p was demonstrated in five MMPs. Enzymatic kinetic studies revealed IC50 values (concentration at 50% inhibition) of 19, 3, 45, 8, and 83 nM for MMP-1, MMP-2, MMP-3, MMP-7, and MMP-9, respectively. Purified rTIMP4p demonstrated a strong inhibitory effect on the invasion of human breast cancer cells across reconstituted basement membranes. Thus, TIMP-4 is a new enzymatic inhibitor in MMP-mediated extracellular matrix degradation and may have therapeutic potential in treating cancer malignant progression.

Computational sequence analysis of the tissue inhibitor of metalloproteinase family

The tissue inhibitor of metalloproteinase (TIMP) family regulates extracellular matrix turnover and tissue remodeling by forming tight-binding inhibitory complexes with matrix metalloproteinases (MMPs). MMPs and TIMPs have been implicated in many normal and pathological processes, such as morphogenesis, development, angiogenesis, and cancer metastasis. This minireview provides information that would aid in classification of the TIMP family and in understanding the similarities and differences among TIMP members according to the physical data, primary structure, and homology values. Calculations of molecular weight, isoelectric point values, and molar extinction coefficients are reported. This study also compares sequence similarities and differences among the TIMP members through calculations of homology within their individual loop regions and the mature region of the molecule. Lastly, this report examines structure-function relationships of TIMPs. Thorough knowledge of TIMP primary and tertiary structure would facilitate the uncovering of the molecular mechanisms underlying metalloproteinase, inhibitory activities and biological functions of TIMPs.