Localization of matrix metalloproteinases and tissue inhibitor of metalloproteinases-2 in normal human and rabbit stomachs

[Pathogenesis of pulmonary fibrosis]

A literature review reflects data on the mechanisms of pulmonary fibrosis after a novel coronavirus infection associated with the SARS-COV2 virus. Factors contributing to post-COVID lung remodeling are considered. According to the literature, in the mechanism of pulmonary fibrosis, during the course of the disease and during the recovery period, both direct viral damage and death of alveolocytes and endothelium, the development of a systemic inflammatory reaction due to inadequate secretion of cytokines, especially type 2, which are activators of the proliferation of fibroblasts and myofibroblasts, are important. The influence of angiogenesis disorders and vascular dysfunction on pneumofibrosis was noted. Attention is also paid to the relationship between the development of pulmonary fibrosis and abnormal activation of the renin-angiotensin-aldosterone system. In combination with the action of many factors, especially germinal ones, an imbalance between profibrogenic and antifibrogenic action develops and fibrosis occurs.

Gastrin stimulates MMP-1 expression in gastric epithelial cells: putative role in gastric epithelial cell migration

The pyloric antral hormone gastrin plays a role in remodeling of the gastric epithelium, but the specific targets of gastrin that mediate these effects are poorly understood. Glandular epithelial cells of the gastric corpus express matrix metalloproteinase (MMP)-1, which is a potential determinant of tissue remodeling; some of these cells express the CCK-2 receptor at which gastrin acts. We have now examined the hypothesis that gastrin stimulates expression of MMP-1 in the stomach. We determined MMP-1 transcript abundance in gastric mucosal biopsies from Helicobacter pylori negative human subjects with normal gastric mucosal histology, who had a range of serum gastrin concentrations due in part to treatment with proton pump inhibitors (PPI). The effects of gastrin were studied on gastric epithelial AGS-GR cells using Western blot and migration assays. In human subjects with increased serum gastrin due to PPI usage, MMP-1 transcript abundance was increased 2-fold; there was also increased MMP-7 transcript abundance but not MMP-3. In Western blots, gastrin increased proMMP-1 abundance, as well that of a minor band corresponding to active MMP-1, in the media of AGS-GR cells, and the response was mediated by protein kinase C and p42/44 MAP kinase. There was also increased MMP-1 enzyme activity. Gastrin-stimulated AGS-GR cell migration in both scratch wound and Boyden chamber assays was inhibited by MMP-1 immunoneutralization. We conclude that MMP-1 expression is a target of gastrin implicated in mucosal remodeling.

Outer membrane inflammatory protein A, a new virulence factor involved in the pathogenesis of Helicobacter pylori

Outer membrane proteins (OMPs) represent an important class of proteins that are observed in gram-negative bacteria, mitochondria and chloroplasts. These proteins play diverse biological roles in protein translocation, cell-cell communication and signal transduction. A variety of OMPs have been identified in the gastrointestinal pathogen Helicobacter pylori (H. pylori) since it was first isolated in 1983. Among these proteins, outer membrane inflammatory protein A (OipA), which is encoded by hopH and unique to this pathogen, is a differentially expressed outer membrane protein that has been confirmed to be directly linked to H. pylori colonization, as well as to the pathogenesis of H. pylori and disease outcome. In this review, we will describe the progress of recent studies on OipA, particularly those on the functions and biological significance of this unique protein.

Association of D2-40 and MMP-1 expression with cyst formation in lung metastatic lesions of cutaneous angiosarcoma on the scalp: immunohistochemical analysis of 23 autopsy cases

Cutaneous angiosarcoma of the scalp can rapidly develop into pulmonary metastasis. The pulmonary metastatic lesions display a unique appearance, so-called thin-walled cysts, which cause a fatal relapsed pneumothorax by rupturing. We analyzed 23 autopsy cases of angiosarcoma with pulmonary metastasis to elucidate the mechanism of the thin-walled cyst development. Of the 23 cases of cutaneous angiosarcoma of the scalp with pulmonary metastasis, radiological examination revealed pulmonary metastatic lesions as thin-walled cysts (39%), nodules (39%), mixed cysts and nodules (13%), and ground-glass opacity (9%). All the cases but one with cystic metastases were complicated by pneumothorax. The cystic lesions were accompanied by podoplanin (D2-40)-positive tumor cells in the luminal surface of the cysts. In both primary cutaneous lesions and pulmonary metastatic lesions, the D2-40 expression was positive for angiosarcoma cells in 100% and 92% of the cases, respectively. While the estrogen-regulated gene (ERG) expression was also positive for most of the primary and metastatic pulmonary angiosarcomas, D2-40 was a more useful marker to differentiate tumor cells from the background than was the ERG expression of the vascular endothelium. Matrix metalloproteinase-1 (MMP-1) expression was also predominant in primary lesions (95%) and pulmonary metastatic lesions (82.6%). Proteinases, like MMP-1, might be associated with a developing thin-walled cyst, although there were no differences in the MMP-1 expression in either the cystic or nodular metastasis. Two extremely aggressive cases showed cystic metastasis with central necrosis that was not observed in other cases. These results suggest a pathogenesis of thin-walled cysts in some progressive cases.

Expressions of MMPs and TIMP-1 in gastric ulcers may differentiate H. pylori-infected from NSAID-related ulcers

Background. Two major causes of gastric ulcers are Helicobacter pylori (H. pylori) infection and nonsteroidal anti-inflammatory drug (NSAID) use. Aims. This study aimed to determine if there were different expressions of matrix metalloproteinases (MMPs) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) between H. pylori-infected and NSAID-related ulcers. Methods. The 126 gastric ulcer patients (H. pylori infected n = 46; NSAID related n = 30; combined with two factors n = 50) provided ulcer and nonulcer tissues for assessment of MMP-3, -7, and -9 and TIMP-1 expression by immunohistochemical staining. Results. Gastric ulcer tissues had significantly higher MMP-3, -7, and -9 and TIMP-1 expressions than nonulcer tissues (P < 0.05). H. pylori-infected gastric ulcers had even higher MMP-7, MMP-9, and TIMP-1 expressions in epithelial cells than NSAID-related gastric ulcers (P < 0.05). In patients with the two combined factors, gastric ulcers expressed similar proportions of antral ulcers and MMP-7 and MMP-9 intensities to NSAID-related gastric ulcers, but lower MMP-9 and TIMP-1 than H. pylori-infected gastric ulcers (P < 0.05). Conclusions. H. pylori-infected gastric ulcers express higher MMP-7, MMP-9, and TIMP-1 than NSAID-related ulcers. In patients with the two combined factors, ulcer location and MMP-7 and MMP-9 intensities are similar to NSAID use.

Effects of lansoprazole on the expression of VEGF and cellular proliferation in a rat model of acetic acid-induced gastric ulcer

BACKGROUND

A recent study reported that in addition to their inhibitory effect on gastric acid secretion, some proton pump inhibitors also exert a cytoprotective effect on the gastric mucosa. We investigated the effects of lansoprazole (LPZ) on the epithelial cell cycle, and on the expressions of vascular endothelial growth factor (VEGF) and matrix metalloproteinase-2 (MMP-2).

METHODS

We examined the effects of 25 and 5 mg/kg LPZ on ulcer healing in an acetic acid-induced ulcer model in rats with and without indomethacin (IND) treatment. On days 14 and 28 after ulcer formation, we compared the ulcer diameter, bromodeoxyuridine (BrdU) uptake, apoptosis, vascular density, and the expressions of VEGF and MMP-2 in the different groups.

RESULTS

LPZ administration increased the BrdU uptake that was reduced by IND administration. LPZ administration also increased VEGF expression at the ulcer margin in a dose-dependent manner. However, LPZ administration did not increase VEGF expression following IND pretreatment. Administration of IND alone significantly decreased MMP-2 expression at the ulcer margin; on the other hand, subsequent administration of LPZ increased the MMP-2 expression.

CONCLUSION

One of the mechanisms of ulcer healing brought about by LPZ may be the involvement of endogenous prostaglandin (PG) secretion. The effect of endogenous PG secretion may be related to the induction of VEGF expression. On the other hand, LPZ administration increased MMP-2 expression, and this effect was not influenced by the inhibition of PG synthesis. The mechanisms of LPZ on ulcer healing may be involved by VEGF expression through endogenous PGs secretion. Additionally, the stimulated expression of MMP-2, which is not secreted by endogenous PGs, is another important factor for ulcer healing by LPZ.

BENEFICIAL EFFECTS OF AUTOLOGOUS BONE MARROW MONONUCLEAR CELL TRANSPLANTATION AGAINST ELASTASE-INDUCED EMPHYSEMA IN RABBITS

The authors investigated whether autologous bone marrow mononuclear cell (BMC) transplantation via the left and right main bronchi would mitigate elastase-induced pulmonary emphysema in rabbits. Four weeks after elastase administration, rabbits also receiving BMCs showed significantly better pulmonary function (FVC, FEV100, FEVPEF) and smaller alveolar airspaces, as indicated by a smaller mean linear intercept, than those receiving porcine pancreatic elastase (PPE) (200 U/kg) alone via the left and right main bronchi. BMCs also significantly reduced cell counts in bronchoalveolar lavage fluid, the incidence of apoptotic (TUNEL-positive) cells and matrix metalloproteinase (MMP)-2 expression, while increasing numbers of proliferative (Ki-67-positive) cells. Thus, BMCs may inhibit the progression to emphysema by attenuating inflammation, MMP-2 expression, and apoptosis, while enhancing alveolar cell proliferation.

Expression of matrix metalloproteinases (MMP)-12 by myofibroblasts during alkali-burned corneal wound healing

PURPOSE

The purpose of this study was to determine the expression of MMP-12 by myofibroblasts during the healing of alkali-burned rabbit corneas (ARC), thus implicating its role in ECM remodeling.

METHODS

Rabbit corneas during alkali burn were examined for MMP-12 mRNA expression by RT-PCR. Immunohistochemistry was used to determine the presence of alpha-SMA, MMP-12 protein, and macrophages. In situ hybridization was performed to identify MMP-12 mRNA expressing cells.

RESULTS

RT-PCR showed that MMP-12 mRNA was expressed in the alkali-burned corneas from one week after the injury. Immunohistochemistry showed myofibroblasts positive for MMP-12 expression. In situ hybridization revealed that MMP-12 mRNA was expressed by myofibroblasts.

CONCLUSION

Our results indicate that, in alkali-burned corneas, myofibroblasts express both MMP-12 mRNA and protein. We suggest that MMP-12 may disintegrate some components of the ECM released after severe alkali burn, which may be involved in the ECM remodeling.

In situ localization of gelatinolytic activity during development and resorption of Meckel's cartilage in mice

Degradation of Meckel's cartilage in the middle portion is accompanied by hypertrophy and death of chondrocytes, calcification of the cartilaginous matrix, and chondroclastic resorption. We hypothesize that the gelatinolytic activity of matrix metalloproteinases (MMPs) largely contributes to the degradation of extracellular matrix (ECM) in the process. The activity in Meckel's cartilage of mouse mandibular arches at embryonic days 14-16 (E14-E16) was examined by a combination of in situ zymography (ISZ), using quenched fluorescent dye-labeled gelatin as a substrate, with CTT (a selective inhibitor of MMP-2 and -9) or with EDTA (a general MMP inhibitor). On E14 and E15, ISZ showed fluorescence in the perichondrium, in the intercellular septa between chondrocytes, and in the nucleus of chondrocytes. CTT attenuated fluorescence, and EDTA eliminated it. On E16, calcified cartilaginous matrix showed intense fluorescence, and dot-like fluorescence was observed in as-yet uncalcified intercellular septa, even after CTT treatment. EDTA inhibited fluorescence, but unexpectedly intense fluorescence was found in the cytoplasm of hypertrophic chondrocytes facing the resorption front. MMP-2, -9, and -13 immunoreactivity was detected in the perichondrium and chondrocytes of Meckel's cartilage. These findings suggest that MMPs and other proteinases capable of degrading gelatin play an integral role in the development, calcification, and resorption of Meckel's cartilage through ECM reconstitution.

Immunohistochemical observation of amniotic membrane patching on a corneal alkali burn in vivo

PURPOSE

To investigate by immunohistochemical observation the effects of amniotic membrane (AM) patching on myofibroblastic differentiation and matrix metalloproteinase (MMP) expression in the corneal stroma after an alkali burn in vivo.

METHODS

A corneal alkali burn was made by placing a circular piece of filter paper containing 1 N NaOH on the central cornea of rabbits. Burning was done unilaterally in each rabbit. Immediately after the wounding, in the AM group, AM was sutured onto the cornea and removed on day 1. Rabbits with no AM patching were controls. On day 14, corneas were excised and immunohistochemical observation was carried out using antibodies against alpha-smooth muscle actin (alpha-SMA), vimentin, MMP-1, MMP-2, MMP-9, and membrane-type1 (MT1)-MMP. Observation after Masson trichrome staining was also performed.

RESULTS

In the AM group, alpha-SMA positive cells were noticeably fewer, and MMP-2, MMP-9, and MT1-MMP expression was clearly inhibited. Also, collagen fibers were more regularly arranged than in control eyes. The more proximate the cells were to the epithelial side, the fewer alpha-SMA-positive cells were observed in the AM group.

CONCLUSIONS

AM patching suppressed myofibroblastic differentiation and MMP expression in the stroma after an alkali burn. An inhibition gradient suggests that AM may release unknown soluble factors possessing some antiscarring capability.

Increased concentration of tissue-degrading matrix metalloproteinases and their inhibitor in complicated diverticular disease

OBJECTIVE

Complicated diverticular disease is associated with extensive structural changes of the colonic wall. Turnover of extracellular matrix (ECM) plays a pivotal role in this process. Proteolytic enzymes, including matrix metalloproteinases (MMPs), are capable of degrading most components of ECM. Their activity is regulated by inhibitors, tissue inhibitors of metalloproteinases (TIMPs). Disturbances of the MMP-TIMP balance can cause tissue degradation or fibrosis. The aim of this study was to assess the concentration and distribution of MMPs and TIMPs in colonic biopsies.

MATERIAL AND METHODS

Twenty-seven patients who had undergone sigmoid colectomy were included in the study. Full-thickness biopsies from affected and non-affected parts of each resected specimen were collected. Expressions of the proteins MMP-1, -2, -3, -9, TIMP-1 and TIMP-2 were quantified by ELISA and localized by immunohistochemistry.

RESULTS

The concentrations of MMP-1, MMP-2 and TIMP-1 were significantly higher in affected tissue than concentrations in non-affected tissue (MMP-1 p=0.005, MMP-2 p=0.0003 and TIMP-1 p<0.0001). In affected segments in general, there was an increased expression in the entire bowel wall, predominantly for MMP-2, MMP-3 and TIMP-1.

CONCLUSIONS

Concentrations of MMP-1, MMP-2 and TIMP-1 were increased in intestinal segments affected by complicated diverticular disease and distributed throughout the entire bowel wall, which may explain the structural changes.

Distribution Profiles of Membrane Type-1 Matrix Metalloproteinase (MT1-MMP), Matrix Metalloproteinase-2 (MMP-2) and Cyclooxygenase-2 (COX-2) in Rabbit Atherosclerosis: Comparison with Plaque Instability Analysis

BACKGROUND

Despite increasing evidence that membrane type 1 matrix metalloproteinase (MT1-MMP), matrix metalloproteinase-2 (MMP-2), and cyclooxygenase-2 (COX-2) are involved in the pathogenesis of atherosclerosis, the possible links among these enzymes remain unclear. Accordingly, we investigated the distribution of MT1-MMP, MMP-2, and COX-2 immunohistologically in the atherosclerotic lesions of hypercholesterolemic (WHHLMI) rabbits.

METHODS AND RESULTS

Distribution of MT1-MMP, MMP-2, and COX-2 was examined by immunohistochemical staining using sixty cross sections of the ascending-arch and thoracic aortas prepared from 4 WHHLMI rabbits. MT1-MMP and MMP-2 staining was prominently observed in the macrophage-rich regions of the atheromatous lesions, and was positively correlated with morphological vulnerability (r=0.63 for MT1-MMP; r=0.60 for MMP-2; p<0.0001). MT1-MMP staining was positively correlated with MMP-2 staining (r=0.61, p<0.0001). COX-2 staining was also the highest in the macrophage-rich regions of the atheromatous lesions, with relatively high staining levels in other more stable lesions.

CONCLUSIONS

Co-distribution of MT1-MMP, MMP-2, and COX-2 was demonstrated in grade IV atheroma, indicating a possible link among these enzymes in the destabilization of atherosclerotic plaques. The relatively high COX-2 distribution in other more stable lesions may indicate its additional roles in the stabilization of atherosclerotic lesions. The present findings in hypercholesterolemic rabbits should help advance our understanding of the pathophysiology of atherosclerosis and provide useful information for the development of new therapeutic and diagnostic (imaging) agents that target MMPs and COX-2 in atherosclerosis.

Balance between polyoma enhancing activator 3 and activator protein 1 regulates Helicobacter pylori-stimulated matrix metalloproteinase 1 expression

Helicobacter pylori infection and elevated expression of tissue matrix metalloproteinase 1 (MMP-1) are both associated with gastric cancer. We investigated the regulation of MMP-1 expression during H. pylori infection. Real-time reverse transcription-PCR was used to examine mucosal MMP-1 mRNA levels in 55 patients with gastric cancers and 61 control patients. Increased MMP-1 mRNA levels in the gastric mucosa and epithelial cells were observed in H. pylori infections in which both the cag pathogenicity island (PAI) and outer inflammatory protein A (OipA) were expressed. The combined induction of c-fos, c-jun, and polyoma enhancing activator-3 (pea-3) by H. pylori caused maximal increase in MMP-1 expression. Activation of the MMP-1 promoter by H. pylori involved occupation of the activator protein 1 (AP-1) sites at -72 and -181 and, surprisingly, vacancy of the -88 PEA-3 site. Electrophoretic mobility shift, supershift, and chromatin immunoprecipitation assays showed increased binding of c-Fos and c-Jun to the -72 and -181 AP-1 sites during H. pylori infection. Importantly, during wild-type H. pylori infection, we detected increased PEA-3 binding to the -72AP-1 site and decreased PEA-3 binding to the -88 PEA-3 site. However, during infection with the cag PAI and oipA mutants, PEA-3 binding to the -88 site was detected. MMP-1 and pea-3 activities are increased in gastric cancers. Maximal activation of MMP-1 transcription requires the cag PAI and OipA, which regulate AP-1 and PEA-3 binding. Thus, cag PAI and OipA provide a possible link between bacterial virulence factors and important host factors related to disease pathogenesis.

Genetic variants in matrix metalloproteinase genes are associated with development of gastric ulcer in H. Pylori infection

BACKGROUND AND AIMS

Matrix metalloproteinases (MMPs) are a family of enzymes that degrade most of the macromolecules making up the extracellular matrix. H. pylori infection increases the secretion of MMPs in the gastric mucosa leading to severe mucosal damage. The aim of this study was to investigate if genetic variants in MMPs involved in the inflammatory response to H. pylori could predispose patients with chronic H. pylori infection to develop gastric ulcer disease.

METHODS

A total of 599 H. pylori-infected patients undergoing gastroscopy were genotyped for 20 SNPs covering the MMP-1, -3, -7, and -9 genes by TaqMan technology. Haplotype and single marker analysis was conducted to assess associations with gastric ulcer disease.

RESULTS

Carriage of allele G of the functional promoter variant MMP-7-181 was significantly associated with gastric ulcer conferring a 1.6-fold increased risk (95% CI: 1.0-2.6, p = 0.037). In addition, carriage of allele A of a coding SNP in exon 6 of MMP-9 confers a 2.4-fold increased risk (95% CI: 1.0-2.6, p = 0.013) for gastric ulcer.

CONCLUSION

The level of association found in this study is in agreement with the nature of a complex genetic disease. Genetic variations in the MMP-7 and -9 gene may be part of a complex genetic risk profile to develop gastric ulcer in chronic H. pylori infection. Further studies are warranted to elucidate the pathophysiological role of these genes in ulcerogenesis.

ONO-4817, a novel matrix metalloproteinase inhibitor, attenuates allograft vasculopathy in a rat cardiac transplant

BACKGROUND

Cardiac allograft vasculopathy (CAV), a disorder characterized by rapid development and progression of obliterative vasculopathy in the transplanted heart, continues to be a major cause of graft failure in long-surviving human transplants. The mechanisms and histopathologic processes of CAV remain unknown. Previous animal studies have shown that inhibition of matrix metalloproteinase (MMP) prevents migration and proliferation of smooth muscle cells in CAV. In this study, we hypothesized that MMPs may be expressed in and may play an important role in CAV.

METHODS

An F344-to-WKAH rat heterotopic heart transplantation model was used. Tacrolimus was administered intramuscularly 14 days after transplantation to prevent acute rejection and to allow the development of CAV. We divided the animals into 2 groups according to post-operative treatment: an ONO group received an MMP inhibitor (ONO-4817) daily by oral gavage for 14 days after transplantation (n = 6), and a control (n = 6) group received no treatment. Grafts were harvested 60 days after treatment.

RESULTS

Immunohistochemical staining revealed that MMP-2 and tissue inhibitors of metalloproteinase-2 (TIMP-2) were expressed more strongly in the neointima and media of the control CAV animals than in the ONO-CAV animals. The animals given ONO-4817 exhibited a significant decrease in the percentage of affected vessels, in the percentage of intimal proliferation, in the intima-to-media ratio, and in the expression of MMP-2 and TIMP-2.

CONCLUSION

These results suggest that MMP-2 and TIMP-2 play an important role in the development of CAV and that the use of an MMP inhibitor (ONO-4817) may prevent neointimal proliferation in patients with CAV.

Gastrin-stimulated gastric epithelial cell invasion: the role and mechanism of increased matrix metalloproteinase 9 expression

The gastric hormone gastrin regulates the organization of the gastric epithelium, but the cellular control mechanisms are yet unknown. Epithelial remodelling typically involves extracellular proteolysis mediated by the matrix metalloproteinases (MMPs). Since a gene-array analysis of the gastric cancer cell line AGS-G(R) suggested that gastrin increased MMP-9 expression, we examined the control of MMP-9 expression by gastrin. Gelatin zymography confirmed gastrin induction of MMP-9 in AGS-G(R) cells, but showed a small inhibition of MMP-2. Immunocytochemical studies showed that MMP-9 was localized to vesicles that appeared to traffic along the processes that were extended in response to gastrin. Gastrin stimulated the invasion of AGS-G(R) cells through artificial basement membrane, which was reduced by an inhibitor of MMP-2/-9. There was also an increase in MMP-9 in the stomach of patients with elevated plasma gastrin and multiple-endocrine neoplasia type 1 (MEN-1) syndrome, suggesting in vivo regulation of MMP-9 expression by gastrin. Finally, we showed that the expression of 1.9 kb of human MMP-9 gene promoter coupled with luciferase (MMP-9-luc) was increased 7.65+/-1.2-fold by gastrin, via a pathway which includes stimulation of protein kinase C, and activation of Raf and the mitogen-activated protein (MAP) kinase pathway. The tumour suppressor menin (which is mutated in MEN-1 syndrome) inhibited the expression of MMP-9-luc by gastrin. These results suggest that gastrin increases MMP-9 expression, which is associated with increased invasion, and this is a putative mechanism regulating remodelling of the gastric epithelium.

Expression and enzymatic activity of MMP-2 during healing process of the acute supraspinatus tendon tear in rabbits

We investigated the spontaneous healing process of a surgically created supraspinatus tendon tear in rabbits with specific reference to the expression of matrix metalloproteinase-2 (MMP-2) and its time-course change in enzymatic activity along with the expression of tissue inhibitors of metalloproteinases (TIMPs). A transverse, full thickness tear of the supraspinatus tendon was created and examined. Immunohistochemical analysis revealed that MMP-2 positive cells were mainly localized at both cutting ends of the tendon, and reparative tissue encroached into the gap from the bursal side. The expression of TIMP-1 was induced in the cells at not only the tendon edges but also the reparative tissue during the healing process. TIMP-2 was constitutively expressed in both the tendon and the reparative tissue. Gelatin zymography using tissue culture media demonstrated latent and active forms of MMP-2 and characteristic time-linked changes of the enzymatic activity. Western blotting confirmed the bands as the latent form of MMP-2. These results suggest that MMP-2 is expressed and activated during the healing process of acute supraspinatus tendon tear and can play an important role in the remodeling process.

Immunohistochemical detection of the 150-kDa oxygen-regulated protein in bladder cancer

OBJECTIVE

To investigate the relationship between the expression of the 150-kDa oxygen-regulated protein (ORP150, which functions as a molecular chaperone in the endoplasmic reticulum for the folding and trafficking of newly synthesized proteins) and the aggressiveness of bladder cancer, and the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs), as the former is a secreting protein through the endoplasmic reticulum and the latter are closely involved in tumour invasion.

MATERIALS AND METHODS

Thirty-nine cystectomy specimens, comprising 12 superficial (pT1) and 27 invasive (pT2-pT4) tumours, were immunohistochemically analysed using antibodies against ORP150, VEGF, MMP-1, MMP-2 and MMP-9. Staining was scored from 0 to 3, according to the ratio of positively staining cells.

RESULTS

Staining was positive (score 1-3) for ORP150 in 10 of 12 superficial and 25 (93%) of the invasive tumours, with a significantly higher staining score for stage T4 than stage T1 tumours. The trend was the same for the staining score of MMP-2, and there was a significant correlation between ORP150 and MMP-2 expression.

CONCLUSIONS

The expression of ORP150 was common in bladder cancer, with a tendency for greater expression in higher stages. The significant correlation between ORP150 and MMP-2 expression suggests that ORP150 acts as a molecular chaperone for MMP-2 secretion and thus tumour invasion.

Gastrin-stimulated gastric epithelial cell invasion: the role and mechanism of increased matrix metalloproteinase 9 expression

The gastric hormone gastrin regulates the organization of the gastric epithelium, but the cellular control mechanisms are yet unknown. Epithelial remodelling typically involves extracellular proteolysis mediated by the matrix metalloproteinases (MMPs). Since a gene-array analysis of the gastric cancer cell line AGS-G(R) suggested that gastrin increased MMP-9 expression, we examined the control of MMP-9 expression by gastrin. Gelatin zymography confirmed gastrin induction of MMP-9 in AGS-G(R) cells, but showed a small inhibition of MMP-2. Immunocytochemical studies showed that MMP-9 was localized to vesicles that appeared to traffic along the processes that were extended in response to gastrin. Gastrin stimulated the invasion of AGS-G(R) cells through artificial basement membrane, which was reduced by an inhibitor of MMP-2/-9. There was also an increase in MMP-9 in the stomach of patients with elevated plasma gastrin and multiple-endocrine neoplasia type 1 (MEN-1) syndrome, suggesting in vivo regulation of MMP-9 expression by gastrin. Finally, we showed that the expression of 1.9 kb of human MMP-9 gene promoter coupled with luciferase (MMP-9-luc) was increased 7.65+/-1.2-fold by gastrin, via a pathway which includes stimulation of protein kinase C, and activation of Raf and the mitogen-activated protein (MAP) kinase pathway. The tumour suppressor menin (which is mutated in MEN-1 syndrome) inhibited the expression of MMP-9-luc by gastrin. These results suggest that gastrin increases MMP-9 expression, which is associated with increased invasion, and this is a putative mechanism regulating remodelling of the gastric epithelium.

Epithelial and bacterial metalloproteinases and their inhibitors in H. pylori infection of human gastric cells

To test the hypothesis that Helicobacter pylori regulates gastric cell secretion of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs), culture media from infected and uninfected human gastric adenocarcinoma (AGS) cells were analyzed by zymography, MMP activity assays, and immunoblotting. AGS cells secreted gelatinolytic (prominently 90 kDa) and caseinolytic (110 kDa) activity together with MMP-1, MMP-3, and TIMP-1, TIMP-2, and TIMP-3 isoforms. H. pylori secreted caseinolytic activity (60 kDa), MMP-3-like enzyme activity, and TIMP-3 immunoreactivity. H. pylori infection increased the 110-kDa caseinolytic activity and induced new gelatinolytic (~35 kDa) and caseinolytic (22 kDa) activities. Infection also increased both basal secretion and activation of MMP-1 and MMP-3, enhanced TIMP-3 secretion, and increased the formation of MMP-3/TIMP-3 complexes. TIMP-1 and TIMP-2 secretion were unchanged. Normal AGS cells showed a pancellular distribution of TIMP-3, with redistribution of immunoreactivity toward sites of bacterial attachment after H. pylori infection. The data indicate that MMP and TIMP secretion by AGS cells is modulated by H. pylori infection and that host MMP-3 and a TIMP-3 homolog expressed by H. pylori mediate at least part of the host cell response to infection.

Role of MMP-2 in alveolar epithelial cell repair after bleomycin administration in rabbits

Matrix metalloproteinases (MMPs) have been implicated in the pathological processes of interstitial lung diseases. However, underlying mechanisms, particularly for activity levels and distribution of activated MMP-2 in the disease process, are yet to be elucidated. The present study investigated the immunolocalization of MMP-2, membrane type 1-matrix metalloproteinase (MT1-MMP), tissue inhibitor of metalloproteinase (TIMP)-2, p53, and Ki-67 in a rabbit model of bleomycin-induced pulmonary fibrosis. Gelatin zymography and in situ zymography were used to examine the activity and the localization of MMP-2. Furthermore, we performed Western blot and in situ hybridization for MT1-MMP, an activator for MMP-2. The total MMP-2 level estimated by gelatin zymography increased significantly at 3, 7, and 14 days after bleomycin administration, compared with controls. In the immunohistochemical study, immunoreaction for MMP-2 was strongest in alveolar epithelial cells among the cell populations. Swollen and/or elongated type II alveolar epithelial cells showed strong immunoreactions for MMP-2, MT1-MMP, and TIMP-2. After bleomycin administration, immunoreaction for p53 was observed in bronchiolar and alveolar epithelial cells. The proportion of p53-positive cells was high in epithelial cells from 1 to 14 days as MMP-2 levels were increased, suggesting that p53 may be responsible, at least in part, for the increase of MMP-2. The ratio of activated MMP-2 to total MMP-2 estimated by gelatin zymography increased significantly at 3, 7, 14, and 28 days after bleomycin treatment. In situ zymography revealed that type II alveolar epithelial cells degraded gelatin. An increased expression of MT1-MMP protein was observed by Western blot following administration of bleomycin. In situ hybridization demonstrated that type II alveolar epithelial cells gave intense signal for MT1-MMP mRNA. These results suggest that type II alveolar epithelial cells express MT1-MMP and activate MMP-2 on their cell surfaces, which may lead to the elongation and migration of alveolar epithelial cells in the repair process of bleomycin-induced pulmonary fibrosis.

Cutaneous carcinomas and preinvasive neoplastic lesions. Role of MMP-2 and MMP-9 metalloproteinases in neoplastic invasion and their relationship with proliferative activity and p53 expression

BACKGROUND

Metalloproteinases (MMPs) are thought to be involved in the process of destruction of basement membranes and stromal invasion by neoplastic epithelial cells.

AIMS

In order to investigate the role of MMPs in cutaneous oncogenesis we studied the expression of MMP-2 and MMP-9 in 34 cases of epidermal preinvasive neoplastic lesions and invasive carcinomas. We also studied their relationship with the expression of tissue inhibitors of MMPs and with proliferative activity and p53 expression in neoplastic epithelial cells.

RESULTS

MMP-9 was found to be focally expressed by neoplastic epithelial cells at the infiltrative edges in microinvasive carcinomas and in dyskeratotic foci in Bowen's disease and widely invasive carcinomas. Gradation of Mib-1 positivity and p53 expression was found with increasing abnormality in the spectrum of malignancy.

CONCLUSIONS

Our results seem to suggest the involvement of MMPs in microinvasive carcinomas, which show also low proliferative activity and p53 expression, whether other factors seem to be more important in widely invasive carcinomas.

Inhibition of matrix metalloproteinase activity attenuates tenascin-C production and calcification of implanted purified elastin in rats

Elastin, a major extracellular matrix protein present in arterial walls provides elastic recoil and resilience to arteries. Elastin is prone to calcification in a number of cardiovascular diseases including atherosclerosis and bioprosthetic heart valve mineralization. We have recently shown that purified elastin when implanted subdermally in rats undergoes severe calcification. In the present study, we used this elastin implant model to investigate the molecular mechanisms underlying elastin calcification. Intense matrix metalloproteinase (MMP-2) and tenascin-C (TN-C) expression were seen in the proximity of the initial cal-cific deposits at 7 days. Gelatin zymography studies showed both MMP-2 (latent and active form) and MMP-9 expression within the implants. To investigate the role of MMPs in calcification, rats were administered a MMP inhibitor, (2S:-allyl-N:-hydroxy-3R:-isobutyl-N:-(1S:-methylcarbamoyl-2-ph enylet hyl)-succinamide (BB-1101) by daily injection, either systemically or at the implant site. The site-specific BB-1101 administration almost completely suppressed TN-C expression, as shown by immunohistochemical staining, within the implants. The systemic BB-1101 injections also significantly reduced TN-C expression within the elastin implants. Moreover, calcification of elastin implants was significantly reduced in the site-specific administration group (5.43 +/- 1.03 microg/mg Ca for BB-1101 group versus 21.71 +/- 1.19 for control group, P: < 0.001). Alizarin Red staining clearly showed that the elastin fibers were heavily calcified in the control group, whereas in BB-1101 group the calcification was scarce with few fibers showing initial calcification deposits. The systemic administration of BB-1101 also significantly reduced elastin calcification (28.07 +/- 5.81 control versus 16.92 +/- 2.56 in the BB-1101 group, P: < 0.05), although less than the site-specific administration. Thus, the present studies indicate that MMPs and TN-C play a role in elastin-oriented calcification.

Matrix metalloproteinases and tissue inhibitor of metalloproteinase-2 in fetal rabbit lung

Cell-extracellular matrix interaction and extracellular matrix remodeling are known to be important in fetal lung development. We investigated the localization of matrix metalloproteinases (MMPs) in fetal rabbit lungs. Immunohistochemistry for type IV collagen, MMP-1, MMP-2, MMP-9, membrane type (MT) 1 MMP, and tissue inhibitor of metalloproteinase (TIMP)-2 and in situ hybridization for MMP-9 mRNA were performed. Gelatin zymography and Western blotting for MT1-MMP in lung tissue homogenates were also studied. MMP-1 and MT1-MMP were detected in epithelial cells, and MMP-2 and TIMP-2 were detected in epithelial cells and some mesenchymal cells in each stage. MMP-9 was found in epithelial cells mainly in the late stage. Gelatin zymography revealed that the ratio of active MMP-2 to latent MMP-2 increased dramatically during the course of development. MT1-MMP was detected in tissue homogenates, especially predominant in the late stage. These findings suggest that MMPs and their inhibitors may contribute to the formation of airways and alveoli in fetal lung development and that activated MMP-2 of alveolar epithelial cells may function to provide an extremely wide alveolar surface.