Platelet-derived collagenase inhibitor: characterization and subcellular localization

Clinical Protocol of Producing Adipose Tissue-Derived Stromal Vascular Fraction for Potential Cartilage Regeneration

Osteoarthritis (OA) is one of the most common debilitating disorders. Recently, numerous attempts have been made to improve the functions of the knees by using different forms of mesenchymal stem cells (MSCs). In Korea, bone marrow concentrates and cord blood-derived stem cells have been approved by the Korean Food and Drug Administration (KFDA) for cartilage regeneration. In addition, an adipose tissue-derived stromal vascular fraction (SVF) has been allowed by the KFDA for joint injections in human patients. Autologous adipose tissue-derived SVF contains extracellular matrix (ECM) in addition to mesenchymal stem cells. ECM excretes various cytokines that, along with hyaluronic acid (HA) and platelet-rich plasma (PRP) activated by calcium chloride, may help MSCs to regenerate cartilage and improve knee functions. In this article, we presented a protocol to improve knee functions by regenerating cartilage-like tissue in human patients with OA. The result of the protocol was first reported in 2011 followed by a few additional publications. The protocol involves liposuction to obtain autologous lipoaspirates that are mixed with collagenase. This lipoaspirates-collagenase mixture is then cut and homogenized to remove large fibrous tissue that may clog up the needle during the injection. Afterwards, the mixture is incubated to obtain adipose tissue-derived SVF. The resulting adipose tissue-derived SVF, containing both adipose tissue-derived MSCs and remnants of ECM, is injected into knees of patients, combined with HA and calcium chloride activated PRP. Included are three cases of patients who were treated with our protocol resulting in improvement of knee pain, swelling, and range of motion along with MRI evidence of hyaline cartilage-like tissue.

Levels of Tissue Inhibitor of Metalloproteinases 1 in Plasma and Urine from Patients with Bladder Cancer

Aim

To assess the potential use of plasma and urine levels of tissue inhibitor of metalloproteinases 1 (TIMP-1) in urothelial cancer.

Methods

TIMP-1 levels were determined in urine and plasma from healthy donors (n=26), patients with bacterial bladder infection (n=24), urothelial bladder adenoma (n=3) or adenocarcinoma (n=7).

Results

Free and total TIMP-1 in plasma were weakly but significantly correlated with age; urinary TIMP-1 was not. A strong correlation between free and total TIMP-1 in plasma was observed, with an average ratio of 0.85. No correlation between total TIMP-1 in urine and plasma was found (p=0.55). No significant differences in free or total TIMP-1 in plasma were found between healthy individuals, patients with cystitis or bladder cancer (p=0.4). Urinary TIMP-1 levels were significantly increased in patients with cystitis (p=0.001). No apparent differences in TIMP-1 levels were found in patients with bladder cancer at different stages.

Conclusion

Our previous observation of a weak but significant correlation between plasma TIMP-1 and age was confirmed. Likewise, an association between free and total TIMP-1 in plasma with a ratio of 0.85 was established. No correlation between plasma and urine TIMP-1 was found. Measurement of TIMP-1 in plasma and/or urine is apparently not useful for the identification of bladder cancer.

Evaluation of Sample Handling in Relation to Levels of Tissue Inhibitor of Metalloproteinases-1 Measured in Blood by Immunoassay

Background

The possible effect of preanalytical conditions such as blood sample preparation and handling on TIMP-1 levels in blood needs thorough investigation.

Materials and Methods

Blood was collected in dry tubes and tubes containing EDTA and kept at 4°C or 20°C for 1, 3, 8, 24 or 72 hours before processing into serum or EDTA plasma. In addition, serum and EDTA plasma samples were frozen and thawed 1–8 times. TIMP-1 was measured by ELISA.

Results

Time to processing for up to 72 hours did not significantly affect TIMP-1 levels in serum. In EDTA plasma, TIMP-1 levels were stable for up to eight hours; however, if samples were kept for 24 hours or longer the TIMP-1 levels increased (p<0.0001). Repeated freezing and thawing had a significant effect on TIMP-1 levels in serum (p=0.04). In plasma, repeated freezing and thawing for up to six times did not influence TIMP-1. However, in plasma samples exposed to seven or eight freeze/thaw cycles TIMP-1 levels decreased, although not significantly (p=0.23).

Conclusions

Handling and processing of blood samples is crucial for TIMP-1 measurement by immunoassay. In serum, TIMP-1 levels are unaffected by time to processing. Plasma samples should be processed within eight hours to avoid a TIMP-1 increase. For the measurement of TIMP-1 in archival material, serum should not be used because TIMP-1 levels are significantly affected by repeated freezing and thawing; archival plasma can readily be used provided that samples have not been frozen and thawed more than six times.

Intraluminal thrombus has a selective influence on matrix metalloproteinases and their inhibitors (tissue inhibitors of matrix metalloproteinases) in the wall of abdominal aortic aneurysms

BACKGROUND

The influence of intraluminal thrombus (ILT) on the proteolytic environment within the wall of an abdominal aortic aneurysm (AAA) is unknown. This is the first study to examine the correlation between ILT thickness and the levels of matrix metalloproteinases (MMPs) and their natural inhibitors (tissue inhibitors of matrix metalloproteinases [TIMPs]) within the adjacent AAA wall.

METHODS

Thirty-five patients undergoing elective repair of AAAs were studied. A single full-thickness infrarenal aortic sample was obtained uniformly from the arteriotomy site from each patient. All samples were snap frozen and analyzed for total and active MMP 2, 8, and 9 and TIMP 1 and 2. Thrombus thickness at the specimen site was measured on the preoperative contrast computed tomographic angiograms.

RESULTS

There was a statistically significant correlation between ILT thickness, concentration of TIMP 1, and active concentration of MMP 9. MMP 2 (active and total) and TIMP 2 demonstrated a positive correlation with ILT thickness, although not statistically significant.

CONCLUSION

In this novel study, we found a significant positive correlation of ILT thickness with active MMP 9 and TIMP 1 concentration in the adjacent AAA wall, and this may have implications for AAA expansion and eventual rupture.

Biology and potential clinical implications of tissue inhibitor of metalloproteinases-1 in colorectal cancer treatment

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the industrialized world. About half of "curatively" resected patients develop recurrent disease within the next 3-5 years despite the lack of clinical, histological and biochemical evidence of remaining overt disease after resection of the primary tumour. Availability of validated biological markers for early detection, selection for adjuvant therapy, prediction of treatment efficacy and monitoring of treatment efficacy would most probably increase survival. Tissue inhibitor of metalloproteinases-1 (TIMP-1) may be such a marker. TIMP-1 inhibits the proteolytic activity of metalloproteinases, which are centrally involved in tumour invasion and metastases. However, in clinical investigations high tumour tissue or plasma levels of TIMP-1 have shown a strong and independent association with a shorter survival time in CRC patients, suggesting that TIMP-1 could have a tumour-promoting function. Furthermore, measurement of plasma TIMP-1 has been shown to be useful for disease detection, with a high sensitivity and high specificity for early-stage colon cancer. This review describes some basic information on the current knowledge of the biology of TIMP-1 as well as the potential use of TIMP-1 as a biological marker in the management of CRC patients.

TIMP-1 as a tumor marker in breast cancer--an update

Improvement of the management of breast cancer patients has high priority. In this regard, prognostic stratification needs to be improved in order to ensure proper medical treatment of all patients and furthermore predictors of response to chemotherapy are urgently needed. As new treatment opportunities emerge in the future this need will continue to grow. Thus, the search for molecular markers of prognosis and prediction is ongoing. Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) has been suggested as a marker of both prognosis and response to treatment. Several studies have demonstrated the association between TIMP-1 and prognosis in breast cancer and new studies within this area have focused on the possibility of using blood samples or paraffin embedded tissue instead of tumor tissue extracts for measurements of TIMP-1. Interestingly, recent studies have investigated the association between TIMP-1 and response to treatment showing that TIMP-1 may also carry predictive information on response to treatment. In this regard, results from studies of the molecular functions of TIMP-1 point to a role of TIMP-1 in the inhibition of tumor cell apoptosis as an explanation for the clinical findings. This review gives an update on the ongoing investigation of the potential role of TIMP-1 as a tumor marker in breast cancer. Furthermore, we link the clinical findings with studies of the molecular actions of the TIMP-1 protein, raising hypotheses that may explain why TIMP-1 could play an important role in future management of breast cancer patients.

Comparative studies of tissue inhibitor of metalloproteinases-1 in plasma, serum and tumour tissue extracts from patients with primary colorectal cancer

OBJECTIVE

We have recently shown that preoperative plasma tissue inhibitor of metalloproteinases-1 (TIMP-1) levels are significantly associated with prognosis of colorectal cancer patients. In addition, we have shown that measurement of plasma TIMP-1 yields information on specificity and sensitivity, which could be used for early detection of colorectal cancer. However, it is not clear whether the increased plasma TIMP-1 levels in colorectal cancer patients are derived from the tumour tissue itself in which it is mainly expressed by the stromal cells located in the vicinity of the cancer cells. The purpose of this study was to examine the association between blood TIMP-1 levels and tumour tissue TIMP-1 levels in colorectal cancer patients.

MATERIAL AND METHODS

Preoperative EDTA plasma, citrate plasma and serum, as well as tumour tissue extracts from 49 colorectal cancer patients were measured with a TIMP-1 ELISA that measures total TIMP-1 levels (non-complexed and complexed TIMP-1).

RESULTS

The median TIMP-1 level in the 49 tumour extracts was 18.7 ng/mg proteins (range 3.5-152.0 ng/mg protein). The median TIMP-1 value was 133.5 ng/ml (range 58.1-559.0 ng/ml) in EDTA plasma, 130.2 ng/ml (range 57.0-572.0 ng/ml) in citrate plasma and 207.2 ng/ml (range 72.6-828.0 ng/ml) in serum. No significant correlations were found between TIMP-1 content in the tumour extracts and in blood.However, EDTA and citrate plasma TIMP-1 levels (r=0.75; p <0.0001) as well as EDTA plasma and serum TIMP-1 levels (r= .064; p<0.0001) were highly correlated.

CONCLUSIONS

The lack of correlation between tumour tissue TIMP-1 and blood levels of TIMP-1 suggests that other sources than the tumour tissue itself may contribute to the increased levels of plasma TIMP-1 in patients with colorectal cancer. However, degradation of cell membranes, rapid secretion into the blood stream and other factors may be responsible for the observed lack of association between TIMP-1 concentrations in blood and tumour tissue extracts.

Tissue inhibitor of metalloproteinase-1 levels in plasma from tumour arteries and veins of patients with rectal cancer

OBJECTIVE

Tissue inhibitor of metalloproteinase-1 (TIMP-1) plays a major role in the regulation of tissue growth, including cancer growth. The TIMP-1 protein can be determined in plasma, and increased plasma levels of TIMP-1 are associated with a poor prognosis of colorectal cancer patients. The aim of the present study was to evaluate whether tumour tissue release of the TIMP-1 protein contributes to the increased plasma levels of TIMP-1 observed in patients with colorectal cancer.

MATERIAL AND METHODS

Preoperative blood samples from a peripheral vein and intraoperative blood samples from a tumour artery, a tumour vein and from a peripheral vein were drawn from 24 patients undergoing elective, intended curative surgery for primary rectal cancer. TIMP-1 levels were determined concurrently in plasma from all samples using a validated ELISA method. Counts of white blood cells and platelets were also carried out.

RESULTS

No significant differences between plasma TIMP-1 levels could be demonstrated in any compartment. In particular, there was no significant difference in TIMP-1 levels in plasma from tumour arteries and tumour veins. However, there was a significant decrease in neutrophil cell counts from tumour arteries to tumour veins (p<0.001).

CONCLUSIONS

The present results do not support the current hypothesis that tumour cells contribute substantially to increased plasma TIMP-1 levels observed in patients with colorectal cancer.

Plasma tissue inhibitor of metalloproteinases-1 as a biological marker? Pre-analytical considerations

Tissue Inhibitor of Metalloproteinases-1 (TIMP-1) may be a valuable biological marker in Colorectal Cancer (CRC). However, prospective validation of TIMP-1 as a biological marker should include a series of pre-analytical considerations. TIMP-1 is stored in platelets, which may degranulate during collection and storage. The aim of this study was to evaluate the influence of platelet TIMP-1 contamination on plasma TIMP-1 levels in healthy volunteers.

MATERIALS AND METHODS

All four parts of this study were done on EDTA-plasma. 1: The effect of stasis was evaluated in plasma collected with and without tourniquet. The collected whole blood was centrifuged at three different g-values. The effect of cellular contamination was evaluated 2: by adding plasma from just above the buffy-coat to one of four tubes containing plasma from the same sample and 3: by separating the plasma into three layers: upper, middle and lower. 4: The effect of temperature was studied by collection and handling of corresponding samples on ice and at room temperature. Prior to analysis samples were stored at -80 degrees C. TIMP-1 was determined using a validated in-house ELISA.

RESULTS

1: TIMP-1 levels in plasma collected with or without stasis were not significantly different. Similarly TIMP-1 levels were not affected by the studied differences in centrifugation force. 2: TIMP-1 levels were significantly increased in plasma potentially contaminated with platelets (p<0.0001). 3: Separation of plasma into an upper, middle and lower layer did not affect the levels of plasma TIMP-1. 4: Samples kept at room temperature following collection showed significantly higher plasma TIMP-1 levels than samples kept on ice (p<0.0001).

CONCLUSION

Contamination with platelets during handling and storage of plasma may have significant effect on TIMP-1 levels. The results can define a standard operating procedure for sample collection and handling, which is important in obtaining uniform, comparable and reproducible plasma TIMP-1 levels.

Evaluation of an improved tissue inhibitor of metalloproteinase 1 dual monoclonal sandwich immunoassay

BACKGROUND

It has previously been shown that increased levels of plasma tissue inhibitor of metalloproteinase 1 (TIMP-1) is associated with shorter survival for patients with colorectal cancer (CRC). Furthermore, plasma TIMP-1 levels have been found to be elevated in patients with early-stage CRC.

OBJECTIVE

It was the aim of this study to develop a new dual monoclonal antibody (mAb) sandwich immunoassay for TIMP-1 in order to achieve better resolution of non-cancer and cancer plasma specimens.

METHODS

Chemiluminescence immunoassay techniques were used to screen 240 combinations of TIMP-1 mAbs for their ability to interact with each other and to allow for further characterization of the sandwiching antibody pairs. Five mAb pair combinations were selected for assessment of their ability to resolve non-cancerous and cancerous plasma specimens by TIMP-1 measurement. Based on this testing, a final assay format was chosen for further validation. The results for the final assay were compared with measurements obtained in a TIMP-1 ELISA that had previously demonstrated the ability to resolve healthy blood donors and CRC specimens.

RESULTS

The clinical results support that the new dual monoclonal immunoassay has statistical discrimination equivalent to the ELISA. Additionally, the immunoassay had a high reproducibility and specificity.

CONCLUSION

The clinical evaluation of five TIMP-1 immunoassays resulted in the development of a new immunoassay. The new TIMP-1 immunoassay showed superior analytical performance to our previously used ELISA.

Association between preoperative plasma levels of tissue inhibitor of metalloproteinases 1 and rectal cancer patient survival

The level of the tissue inhibitor of metalloproteinases 1 (TIMP-1) has previously been demonstrated to predict the survival of early stage colorectal cancer patients. The present study was undertaken to further validate plasma TIMP-1 as a prognostic marker in rectal cancer. Preoperative plasma from 352 rectal cancer patients were analysed using an immunoassay for TIMP-1. The TIMP-1 immunoassay demonstrated robustness and good reproducibility with low interassay coefficients of variation (CV). The rectal cancer patients had a mean plasma TIMP-1 level of 184 microg/l (standard deviation (SD): 70 microg/l). There were no significant differences in TIMP-1 levels between patients with Dukes' stage A, B or C disease, whereas Dukes' stage D patients had significantly increased TIMP-1 levels (P<0.0001); however, high levels of TIMP-1 were not restricted to those with advanced disease. Univariate analysis demonstrated an increasing risk of mortality with increasing TIMP-1 levels Hazard Ratio (HR)=2.9; 95% Confidence Interval (CI): 1.7-5.0; P<0.0001). Including additional covariates, multivariate analysis identified plasma TIMP-1 as an independent prognostic marker (HR=2.2; 95% CI: 1.2-4.1 (P=0.01). This study showed a highly significant and independent association between preoperative plasma TIMP-1 levels and survival in rectal cancer patients, thus confirming our previous findings. Furthermore, the TIMP-1 immunoassay proved to be stable and reproducible in this confirmatory study.

Identification, regulation and role of tissue inhibitor of metalloproteinases-4 (TIMP-4) in human platelets

1. Matrix metalloproteinase-2 (MMP-2) released during activation of human platelets by aggregating agents and cancer cells is known to stimulate platelet aggregation. 2. The expression, activity and role of tissue inhibitors of metalloproteinases (TIMPs), natural inhibitors of MMPs, in isolated human platelets were investigated. 3. Western blot, reverse zymography, immunogold electron microscopy, aggregometry (collagen-, thrombin and HT-1080 human fibrosarcoma cells-induced aggregation), flow cytometry and the release of (14)C-serotonin from labelled platelets recruited to the aggregate were used to characterize the presence and function of platelet TIMPs. 4. TIMP-4 (23 kDa) has been identified as the major MMP inhibitor (12-16 ng per 10(8) platelets) in human platelets. Platelets expressed lower (<1 ng per 10(8) platelets) amounts of TIMP-1. No other TIMPs were detected using Western blot analysis. 5. TIMP-4 co-localized with MMP-2 in resting platelets and was released upon platelet aggregation induced by collagen and thrombin. 6. Collagen resulted also in the release of higher molecular weight (60 kDa) complexes of TIMP-4. 7. The release of TIMP-4 was reduced by prostacyclin and S-nitroso-glutathione (GSNO), an NO donor. 8. Human recombinant TIMP-4 (rTIMP-4), but not human rTIMP-1, inhibited partially both platelet aggregation and recruitment. 9. The recombinant TIMP-4 potentiated the recruitment inhibitor effects of GSNO. 10. TIMP-4 was not released during platelet aggregation induced by HT-1080 cells. 11. Human rTIMP-4 exerted a biphasic effect on HT-1080 cells-induced aggregation. 12. Thus, TIMP-4 is the major intraplatelet MMP inhibitor and it is involved in regulation of platelet aggregation and recruitment.

Stromal-derived factor 1–induced megakaryocyte migration and platelet production is dependent on matrix metalloproteinases

Despite the discovery of thrombopoietin (TPO) and its contribution to megakaryocytopoiesis, the exact mechanisms and sites of platelet production are unknown. It has been shown that mature megakaryocytes (MKs) functionally express the stromal-derived factor 1 (SDF-1) receptor, CXCR4. SDF-1–induced migration of mature MKs through endothelial cell layers results in increased platelet production. Because the migration of polyploid MKs from the bone marrow microenvironment requires remodeling of the perivascular extracellular matrix, it was hypothesized that mature polyploid MKs may express matrix metalloproteinases (MMPs), facilitating their exit into the bone marrow extravascular space. In this report, it is demonstrated that SDF-1 induces the expression and release of gelatinase B (MMP-9) by purified mature polyploid human MKs and an adeno-CXCR4–infected megakaryocytic cell line. Neutralizing antibody to MMP-9, but not MMP-2, blocked SDF-1–induced migration of MKs through reconstituted basement membrane, suggesting that expression of MMP-9 is critical for MK migration. Incubation of mature MKs with a synthetic MMP inhibitor, 5-phenyl-1,10-phenanthrolene, resulted in the inhibition of platelet formation, suggesting that the expression of MMPs is not only critical for megakaryocyte migration but also for subsequent platelet release. Confirming these results, adeno-SDF-1 injection into normal mice resulted in increased platelet counts, a process that could be blocked by a synthetic MMP inhibitor. These results suggest mobilization of MKs involves sequential expression and activation of chemokine receptors such as CXCR4, MMP-9, followed by transendothelial migration. MMP inhibitors may have potential use in the treatment of thrombotic and myeloproliferative disorders.

Stromal-derived factor 1–induced megakaryocyte migration and platelet production is dependent on matrix metalloproteinases

Despite the discovery of thrombopoietin (TPO) and its contribution to megakaryocytopoiesis, the exact mechanisms and sites of platelet production are unknown. It has been shown that mature megakaryocytes (MKs) functionally express the stromal-derived factor 1 (SDF-1) receptor, CXCR4. SDF-1–induced migration of mature MKs through endothelial cell layers results in increased platelet production. Because the migration of polyploid MKs from the bone marrow microenvironment requires remodeling of the perivascular extracellular matrix, it was hypothesized that mature polyploid MKs may express matrix metalloproteinases (MMPs), facilitating their exit into the bone marrow extravascular space. In this report, it is demonstrated that SDF-1 induces the expression and release of gelatinase B (MMP-9) by purified mature polyploid human MKs and an adeno-CXCR4–infected megakaryocytic cell line. Neutralizing antibody to MMP-9, but not MMP-2, blocked SDF-1–induced migration of MKs through reconstituted basement membrane, suggesting that expression of MMP-9 is critical for MK migration. Incubation of mature MKs with a synthetic MMP inhibitor, 5-phenyl-1,10-phenanthrolene, resulted in the inhibition of platelet formation, suggesting that the expression of MMPs is not only critical for megakaryocyte migration but also for subsequent platelet release. Confirming these results, adeno-SDF-1 injection into normal mice resulted in increased platelet counts, a process that could be blocked by a synthetic MMP inhibitor. These results suggest mobilization of MKs involves sequential expression and activation of chemokine receptors such as CXCR4, MMP-9, followed by transendothelial migration. MMP inhibitors may have potential use in the treatment of thrombotic and myeloproliferative disorders.

TIMP-1/MMP-9 imbalance in an EBV-immortalized B lymphocyte cellular model: evidence for TIMP-1 multifunctional properties

Tissue inhibitors of metalloproteinases (TIMPs) were initially described as agents controlling metalloproteinase activity. The purpose of this study was to investigate the expression and the roles of TIMP-1 secreted by Epstein-Barr-virus (EBV)-immortalized B lymphocytes. TIMP-1 was isolated from conditioned medium of interleukin (IL)-1beta stimulated EBV-B lymphocytes; purified TIMP-1 was identified by mass spectrometry and immunochemistry. TIMP-1-free MMP-9 was quantified after purification by zymography and enzyme-linked immunosorbent assay. EBV-B lymphocyte-secreted TIMP-1 inhibited MMP-9 gelatinolytic activity resulting in decreased B-cell transmigration as measured in vitro. The release of huge amounts of TIMP-1 in proportion to MMP-9 from B lymphocytes after EBV transformation was shown to be correlated with secretion of IL-10 and dependent on culture time. In contrast, there was little TIMP-1 and almost no IL-10 released from native B cells, suggesting a possible IL-10 mediated autocrine regulation mechanism of TIMP-1 synthesis. The MMP-9/TIMP-1 imbalance observed in the culture medium of EBV-B lymphocytes (TIMP-1>MMP-9) and of native B cells (MMP-9>TIMP-1) is suggestive of a new function for TIMP-1. We propose that TIMP-1 acts as a survival factor controlling B-cell growth and apoptosis through an autocrine regulation process involving IL-10 secreted by EBV-B lymphocytes.

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in synovial fluids from patients with rheumatoid arthritis or osteoarthritis

OBJECTIVE

Matrix metalloproteinases (MMPs) are expressed in joint tissues of patients with rheumatoid arthritis (RA) and osteoarthritis (OA). The objective of this study was to define the steady state levels of seven different MMPs and two tissue inhibitors of metalloproteinases (TIMPs) as well as the potential metalloproteinase activity in the synovial fluid (SF) to provide more insight into the role of MMPs in cartilage destruction in RA and OA.

METHODS

Levels of MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-13, TIMP-1, and TIMP-2 in SF aspirated from knee joints of 97 patients with RA and 103 patients with OA were measured by the corresponding one step sandwich enzyme immunoassays. Proteolytic activity of MMPs in these SFs was examined in an assay using [(3)H]carboxymethylated transferrin substrate in the presence of inhibitors of serine and cysteine proteinases after activation with p-aminophenylmercuric acetate (APMA). Destruction of RA knee joints was radiographically evaluated.

RESULTS

Levels of MMP-1, MMP-2, MMP-3, MMP-8, and MMP-9 were significantly higher in RA SF than in OA SF. MMP-7 and MMP-13 were detectable in more than 45% of RA SFs and in less than 20% of OA SFs, respectively. Among the MMPs examined, MMP-3 levels were extremely high compared with those of other MMPs. Direct correlations were seen between the levels of MMP-1 and MMP-3 and between those of MMP-8 and MMP-9 in RA SF. Although the levels of MMP-1 and MMP-3 increased even in the early stage of RA, those of MMP-8 and MMP-9 were low in the early stage and increased with the progression of RA. Molar ratios of the total amounts of the MMPs to those of the TIMPs were 5.2-fold higher in patients with RA than in OA, which was significant. APMA-activated metalloproteinase activity in SF showed a similar result, and a direct correlation was seen between the molar ratios and the activity in RA SF.

CONCLUSIONS

Our results show that high levels of MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, and TIMP-1 are present in RA SF and suggest that once these MMPs are fully activated, they have an imbalance against TIMPs, which may contribute to the cartilage destruction in RA.

Quantitation of TIMP-1 in plasma of healthy blood donors and patients with advanced cancer

A kinetic enzyme-linked immunosorbent assay (ELISA) for plasma tissue inhibitor of metalloproteinase (TIMP)-1 was developed in order to examine the potential diagnostic and prognostic value of TIMP-1 measurements in cancer patients. The ELISA enabled specific detection of total TIMP-1 in EDTA, citrate and heparin plasma. The assay was rigorously tested and requirements of sensitivity, specificity, stability and good recovery were fulfilled. TIMP-1 levels measured in citrate plasma (mean 69.2+/-13.1 microg I(-1)) correlated with TIMP-1 measured in EDTA plasma (mean 73.5+/-14.2 microg I(-1)) from the same individuals in a set of 100 healthy blood donors (Spearman's rho = 0.62, P< 0.0001). The mean level of TIMP-1 in EDTA plasma from 143 patients with Dukes' stage D colorectal cancer was 240+/-145 microg I(-1) and a Mann-Whitney test demonstrated a highly significant difference between TIMP-1 levels in healthy blood donors and colorectal cancer patients (P < 0.0001). Similar findings were obtained for 19 patients with advanced breast cancer (mean 292+/-331 microg I(-1)). The results show that TIMP-1 is readily measured in plasma samples by ELISA and that increased levels of TIMP-1 are found in patients with advanced cancer. It is proposed that plasma measurements of TIMP-1 may have value in the management of cancer patients.

Major co-localization of the extracellular-matrix degradative enzymes heparanase and gelatinase in tertiary granules of human neutrophils

The expression of cell-surface adhesion proteins and the release of extracellular-matrix degradative enzymes constitute crucial processes for the attachment of neutrophils to the endothelium and for the subsequent extravasation of these cells through the endothelial layer. We have analysed in resting human neutrophils the subcellular localization of heparanase, a heparan-sulphate-degrading endoglycosidase that can degrade basement-membrane components, thereby facilitating neutrophil passage into the tissue during an inflammatory reaction. By subcellular fractionation of postnuclear supernatants from resting human neutrophils on continuous sucrose gradients, we have found that heparanase activity was mainly located in gelatinase-containing tertiary granules. Using a specific antibody, the 96-kDa heparanase protein was further located in the gelatinase-rich subcellular fractions. Following immunoblotting and immunoprecipitation analysis in the distinct subcellular fractions, we also found co-localization of heparanase and Mo1 (CD11b/CD18), a leucocyte integrin involved in the attachment of neutrophils to the endothelium, in the fractions enriched in gelatinase-containing tertiary granules. Treatment of human neutrophils with tumour necrosis factor or granulocyte/macrophage colony-stimulating factor induced an increase in the CD11b/CD18 cell-surface expression, as well as the release of both gelatinase (matrix metalloproteinase-9) and heparanase, but not of other granule markers, indicating a major co-localization of gelatinase, heparanase and CD11b/CD18 in the same organelle. Furthermore, confocal laser scanning microscopy using specific antibodies against gelatinase and heparanase revealed a major co-localization of both enzymes in intracellular cytoplasmic granules. The major localization of heparanase and CD11b/CD18 in the gelatinase-containing tertiary granule supports the notion that mobilization of this organelle can regulate extravasation of human neutrophils.

Analytical aspects regarding the measurement of metalloproteinases and their inhibitors in blood

OBJECTIVE

Both in vitro and in vivo investigations have shown that the balance between matrix metalloproteinases (MMP) and the tissue inhibitors of metalloproteinases (TIMP) seems to be important in physiological and pathological processes which involve tissue remodeling and repair.

DESIGN AND METHODS

In order to investigate the analytical reliability of new commercial ELISA tests. BIOTRAK test kits (Amersham Int.) were used for the determination of metalloproteinase-1 (MMP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1), and the MMP-1/TIMP-1 complex in blood.

RESULTS

The detection limits and the precision data were in the usual ranges of ELISA tests so that concentrations found in blood could be determined reliably. Since all three analytes were lower in heparin plasma than in serum or EDTA plasma, heparin plasma was selected as the specimen of choice. Measurement of diluted samples gave higher values than those of undiluted native plasma samples because the inhibitory effects of specific/unspecific inhibitors or other matrix components were apparently reduced. To obtain comparable data from different laboratories, the predilution of samples must be defined. We recommend to use diluted plasma samples of 1:5, 1:21, and 1:11 for the determination of MMP-1, TIMP-1, and the complex MMP-1/TIMP1, respectively. The preliminary upper 95% reference limits measured under these conditions in healthy subjects (40 females: 40 males) were 14.4 micrograms/L for MMP-1 in females, 20 micrograms/L for MMP-1 in males. 1668 micrograms/L for TIMP-1 and 116 micrograms/L for the complex MMP-1/TIMP-1.

CONCLUSION

The study has shown that the BIOTRAK test combinations for MMP-1, TIMP-1, and MMP-1/TIMP-1 complex allow a reliable measurement of the analyte concentrations in heparin plasma. In order to avoid preanalytical misinterpretations only heparin plasma samples in defined dilutions should be used.

Significance of serum tissue inhibitor of metalloproteinases-1 in various liver diseases

BACKGROUND/AIMS

This study was performed to assess the significance of elevated serum tissue inhibitor of metalloproteinases-1 concentration in various liver diseases.

METHODS

Tissue inhibitor of metalloproteinases-1 levels were measured in patients with various liver diseases, and were compared with serum type III procollagen-N-peptide (P III P), type IV collagen and laminin P1 levels, as well as with the histology of liver biopsy specimens.

RESULTS

Mean tissue inhibitor of metalloproteinases-1 levels were significantly higher in subjects with acute viral hepatitis, cirrhosis, alcoholic hepatitis, and alcoholic cirrhosis than in the control group (p < 0.05). Serum tissue inhibitor of metalloproteinases-1 levels in the various liver diseases showed positive correlation with serum type IV collagen, P III P, and laminin P1 levels. Regarding the relationship between tissue inhibitor of metalloproteinases-1 and liver histology, serum tissue inhibitor of metalloproteinases-1 levels correlated with the degree of hepatic fibrosis and inflammation, such as focal necrosis and cell infiltration. Furthermore, elevated serum tissue inhibitor of metalloproteinases-1 levels were especially related to the cell infiltration, focal necrosis, portal fibrosis, and serum type IV collagen level.

CONCLUSIONS

These findings suggest that the measurement of the serum tissue inhibitor of metalloproteinases-1 level in various liver diseases may be useful to estimate the active hepatic fibrogenesis associated with the active inflammatory stage of the liver injury.

Evidence for the tissue inhibitor of metalloproteinases-1 (TIMP-1) in human polymorphonuclear leukocytes

A tissue inhibitor of metalloproteinases (TIMP)-1 was isolated from human polymorphonuclear leukocytes (PMNL) in a complex with latent 95-kDa gelatinase (matrixmetalloproteinase, MMP-9). It was separated from the enzyme by gel filtration in the presence of SDS. Using a competitive ELISA procedure, we determined that 10% of the isolated gelatinase was complexed with TIMP-1. The presence of the inhibitor in isolated PMNL could also be demonstrated by indirect immunofluorescence using a specific antibody against TIMP-1. Cellular mRNA was isolated from PMNL, which were highly purified by separation via formylMet-Leu-Pro-stimulated chemotactic migration in a Boyden chamber. Using reverse-transcription PCR and Northern blotting, TIMP-1 mRNA was shown to be present in PMNL, suggesting that these cells are also capable of synthesizing TIMP-1.

Increased levels of stromelysin-1 and tissue inhibitor of metalloproteinases-1 in sera from patients with rheumatoid arthritis

OBJECTIVE

To evaluate the efficacy of stromelysin-1 (matrix metalloproteinase-3 [MMP-3]) and tissue inhibitor of metalloproteinases-1 (TIMP-1) in serum as markers for joint inflammation in rheumatoid arthritis (RA).

METHODS

Levels of both macromolecules in sera from 97 healthy controls, 109 patients with RA, and 47 patients with osteoarthritis (OA) were measured by respective 1-step sandwich enzyme immunoassays. In the patients with RA, serum levels of MMP-3 and TIMP-1 were investigated in relation to laboratory and clinical measures of disease activity. In addition, the relationships between serum and synovial fluid (SF) levels in paired samples from individual patients were examined.

RESULTS

Serum levels of both MMP-3 and TIMP-1 in RA patients were significantly higher than those in OA patients and in healthy controls (P < 0.001), and were shown to correlate with traditional systemic markers of inflammation including the erythrocyte sedimentation rate and C-reactive protein level, and with the Lansbury articular index. In addition, it was noted that serum levels of MMP-3 correlated with the corresponding values in paired SF samples obtained concurrently from patients with RA (rs = 0.588, P < 0.001), while such correlations were not found for TIMP-1 levels.

CONCLUSION

Our results support the notion that levels of both MMP-3 and TIMP-1 in RA patient sera are increased in association with inflammation. Furthermore, the level of MMP-3 in serum provides a particularly useful marker of inflammatory activity in the joints of patients with RA.

Inhibition of angiogenesis by tissue inhibitor of metalloproteinase

Matrix proteases play a critical role in cell invasion and migration, including the process of angiogenesis. The ability of specific factors to induce angiogenic responses correlates with their stimulation of matrix protease synthesis and release. Using an in vivo angiogenesis assay, the endothelial cell response to known angiogenic factors, basic fibroblast growth factor (bFGF) and adipocyte conditioned medium, was blocked by an inhibitor of matrix metalloproteinase activity, TIMP-1. The TIMP effect was mediated, at least in part, through the inhibition of endothelial cell migration, as determined by the ability of TIMP to block chemotaxis in a Boyden chamber assay. These results indicate that the inhibition of migration is a direct effect on the endothelial cells and does not require accessory cells. An additional observation was that the RNA levels for TIMP were significantly reduced in differentiated adipocytes, compared to undifferentiated F442A controls. Therefore, the acquisition of an angiogenic phenotype may involve not only the induction of positive factors, but also the suppression of angiogenesis inhibitors.

Dissociation of collagenase-tissue inhibitor of metalloproteinases-1 (TIMP-1) complex--its application for the independent measurements of TIMP-1 and collagenase activity in crude culture media and body fluids

Collagenase-tissue inhibitor of metalloproteinases-1 (TIMP-1) complex was prepared from activated collagenase and TIMP-1 purified from culture media of human skin fibroblasts. After having been confirmed to be a complex by zinc chelate chromatography, the complex was demonstrated to dissociate by passage through an anti-TIMP-1 monoclonal antibody-affinity column. On the basis of above evidence, a simple strategy was set up for the independent measurements of TIMP-1 concentration, and both active and total collagenase activities in crude culture media and body fluids.

Polyclonal and monoclonal antibodies against human tissue inhibitor of metalloproteinases (TIMP) and the design of an enzyme-linked immunosorbent assay to measure TIMP

Both polyclonal and monoclonal antibodies have been raised against purified human fibroblast tissue inhibitor of metalloproteinases (TIMP) and characterised. Combinations of antibodies were tested for their suitability in a double antibody sandwich ELISA to measure TIMP. Two combinations were applicable to the immunoassay: (i) a monoclonal capture antibody with a polyclonal detecting antibody; (ii) two monoclonal antibodies. The assay range was (i) 2-50 ng/ml and (ii) 5-50 ng/ml of human TIMP. The levels of TIMP in several human body fluids were measured using assay (ii), and values in ng/ml with standard deviations (n-1) obtained as follows: serum, 299 +/- 62; plasma, 109 +/- 35; amniotic fluid, 724 +/- 62; cerebrospinal fluid, 144 +/- 156; saliva, 209 +/- 103.

Human 72-kilodalton type IV collagenase forms a complex with a tissue inhibitor of metalloproteases designated TIMP-2

Simian virus 40 (SV40)-transformed human lung fibroblasts secrete both 72-kDa type IV collagenase and a closely related 92-kDa type IV collagenase that was not detected in the parental cell line. The 92-kDa type IV procollagenase purified from these cells exists in a noncovalent complex with the tissue inhibitor of metalloproteases, TIMP. Here we report that the 72-kDa type IV procollagenase purified from HRAS-transformed human bronchial epithelial cells, SV40-transformed lung fibroblasts, and normal skin fibroblasts exists in a stable but noncovalent stoichiometric complex with a 24-kDa inhibitor referred to here as "TIMP-2." TIMP-2 is closely related to TIMP, as demonstrated by comparison of the partial amino acid sequence of this protein to that of TIMP, although it does not cross-react with TIMP-specific antibody. The TIMP-2 inhibitor interacts with the 72-kDa type IV collagenase in preference to the 92-kDa type IV collagenase that forms a complex exclusively with TIMP. The 72-kDa type IV collagenase-TIMP-2 complex can be activated with organomercurials to yield a catalytically competent enzyme. Activation occurs concomitantly with autoproteolytic cleavage of the amino terminus of the protein and does not require dissociation of the complex. Both activity and activation of the complex can be completely inhibited by further addition of stoichiometric quantities of purified TIMP-2 or recombinant TIMP.

Increased immunostaining of collagenase and TIMP in eruptive xanthoma

Remodeling of the extracellular matrix is an important function of interstitial collagenase. The activity of this enzyme forms the initial and rate limiting step in collagen degradation; moreover, this enzyme appears representative of a family of connective tissue metalloproteinases. Conversely, a widely distributed glycoprotein, tissue inhibitor of metalloproteinases (TIMP), may be an important regulator of matrix degradation. To study the roles of collagenase and TIMP in pathologically altered dermal connective tissue, immunohistochemistry was used to localize collagenase and TIMP in an eruptive xanthoma, a chronic tuberous xanthoma, and normal skin. Normal skin and the chronic tuberous xanthoma showed mild diffuse staining of both proteins throughout the dermis. In contrast, intense dermal staining of both collagenase and TIMP was present in the eruptive xanthoma. Thus, the marked accumulation of lipid in dermal macrophages was associated with a significant increase in matrix collagenase and TIMP. This increase may reflect direct production of these two proteins by macrophages. Alternatively, it may be due to increased production by fibroblasts stimulated by macrophage-derived cytokines. The balance of degradative and inhibitory activities in the extracellular matrix may regulate the extent and nature of dermal remodeling.

Human osteoblasts in vitro secrete tissue inhibitor of metalloproteinases and gelatinase but not interstitial collagenase as major cellular products

Human osteoblast cultures (hOB) were examined for the production of interstitial collagenase, tissue inhibitor of metalloproteinases (TIMP), and gelatinolytic enzymes. Cells were isolated by bacterial collagenase digestion of trabecular bone (vertebra, rib, tibia, and femur) from 11 subjects (neonatal to adult). Confluent cultures were exposed to phorbol 12-myristate 13-acetate, PTH, PGE2, epidermal growth factor, 1,25(OH)2 vitamin D3, recombinant human IL-1 beta, and dexamethasone. Collagenase and TIMP were assayed immunologically and also by measurements of functional activity. Collagenase was not secreted in significant quantities by human bone cells under any tested condition. Furthermore, collagenase mRNA could not be detected in hOB. However, hOB spontaneously secreted large amounts of TIMP for at least 72 h in culture. hOB TIMP was found to be identical to human fibroblast TIMP by double immunodiffusion, metabolic labeling and immunoprecipitation, Northern blot analysis, and stoichiometry of collagenase inhibition. SDS-substrate gel electrophoresis of hOB-conditioned media revealed a prominent band of gelatinolytic activity at 68 kD, and specific polyclonal antisera established its identity with the major gelatinolytic protease of human fibroblasts. Abundant secretion of gelatinolytic, but not collagenolytic, enzymes by hOB may indicate that human osteoblasts do not initiate and direct the cleavage of osteoid collagen on the bone surface, but may participate in the preparation of the bone surface for osteoclast attachment by removal of denatured collagen peptides. The constitutive secretion of TIMP may function to regulate metalloproteinase activity.

Disruption of the subendothelial basement membrane during neutrophil diapedesis in an in vitro construct of a blood vessel wall

To examine the course of physiologic interactions between extravasating neutrophils and the subendothelial basement membrane, a model of the venular vessel wall was constructed by culturing human umbilical vein endothelial cells on a collagen matrix. After 21 d in culture, the endothelial cell monolayer displayed in vivo-like intercellular borders and junctions, deposited a single-layered, continuous basement membrane that was impenetrable to colloidal particles, and supported neutrophil extravasation in a physiologic manner. Using this model, we demonstrate that neutrophil transmigration in a plasma milieu was associated with a significant disruption of the retentive properties of the basement membrane in the absence of discernable morphologic changes. The loss of basement membrane integrity associated with neutrophil diapedesis was not dependent on neutrophil elastase or cathepsin G and was resistant to inhibitors directed against neutrophil collagenase, gelatinase, and heparanase. Despite the fact that this loss in matrix integrity could not be prevented, basement membrane defects were only transiently expressed before they were repaired by the overlying endothelium via a mechanism that required active protein and RNA synthesis. These data indicate that neutrophil extravasation and reversible basement membrane disruption are coordinated events that occur as a consequence of vessel wall transmigration.

Synthesis of latent collagenase and collagenase inhibitor by bovine aortic medial explants and cultured medial smooth muscle cells

Bovine aortic medial tissue and medial smooth muscle cells were demonstrated for the first time to synthesize a latent collagenase together with collagenase inhibitor in culture. Molecular weights of the latent collagenase and its inhibitor derived from aortic medial tissue explant were estimated to be about 52 K by gel filtration and 26.5 K by electrophoresis, respectively. Activated aortic collagenases cleaved type I collagen in solution into 3/4 (alpha A) and 1/4 (alpha B) length cleavage fragments and were inhibited by EDTA, o-phenanthroline, dithiothreitol, bovine serum, and highly purified dental pulp and aortic collagenase inhibitors. The aortic inhibitors showed inhibitory activity against all the animal collagenases tested, except for bacterial collagenase. Double-immunodiffusion analysis using a monospecific antiserum prepared against dental pulp inhibitor showed that the aortic inhibitors are immunologically identical to the pulp inhibitor. Using the same antiserum, we found immunoreactive collagenase inhibitor protein to be localized along the collagen fibers between elastic membranes in aortic medial tissue.

Immunolocalization of collagenase inhibitor in normal skin and basal cell carcinoma

Human collagenase inhibitor is a ubiquitous glycoprotein capable of blocking the action of several connective tissue metalloproteinases, including collagenase, gelatinase, and proteoglycanase. The action of this proteinase inhibitor may constitute a pivotal step in the control of connective tissue matrix degradation. Using monospecific antibody to collagenase inhibitor as an immunocytochemical probe, we determined its in vivo localization in normal human skin and in a pathologic state, the altered connective tissue stroma surrounding basal cell carcinoma. Collagenase inhibitor was localized diffusely throughout the dermis and appeared to be associated with the extracellular matrix components, both in normal skin and in basal cell carcinoma. Intense staining was present in the stroma surrounding islands of basal cell carcinoma. The increased amounts of collagenase inhibitor may be a result of its production by stromal fibroblasts stimulated by cytokines of tumor or inflammatory cell origin. These findings are similar to those previously described for dermal collagenase. Both collagenase inhibitor and collagenase itself appear to be normal components of the extracellular matrix, and amounts of both are increased in the altered stroma surrounding neoplastic cells. Thus we suggest that the balance of degradative proteinase(s) to specific inhibitor may be an important factor in determining the composition of the extracellular matrix.

Regulation of the expression of tissue inhibitor of metalloproteinases and collagenase by retinoids and glucocorticoids in human fibroblasts

The regulation of the expression of interstitial collagenase and tissue inhibitor of metalloproteinases (TIMP) was examined in response to both retinoid compounds and glucocorticoids. Effective retinoids induced a dose-dependent, specific increase in the production of TIMP of approximately two- to threefold by monolayer cultures of human fibroblasts derived from various tissues, while simultaneously causing a decrease in collagenase secretion of similar magnitude. These effects were apparent by 8-12 h in culture and disappeared within 24 h after the withdrawal of retinoid compounds. The retinoid effect on TIMP production was mediated via an increased biosynthesis of new inhibitor protein. Similarly, increased steady state levels of TIMP messenger RNA (mRNA) accompanied by decreased quantities of collagenase mRNA were demonstrated, suggesting transcriptional control of the retinoid action. The data suggest that retinoids co-regulate the expression of collagenase and TIMP, and do so in an inverse manner. Dexamethasone caused a dose-dependent, specific decrease in collagenase production without altering the biosynthesis of TIMP. These findings were paralleled by a marked reduction in collagenase mRNA, without any accompanying change in TIMP mRNA. Therefore, TIMP and collagenase expression appear to be independently modulated by glucocorticoids.

Monoclonal antibodies to bovine collagenase inhibitor

Hybridoma antibodies against bovine collagenase inhibitor were produced by fusion of myeloma cells NS-1 (P3-NS1-1) with spleen cells from mice hyperimmunized with collagenase inhibitor purified from the explant medium of bovine dental pulps. Hybridomas positive by an enzyme-linked immunosorbent assay (ELISA) for bovine collagenase inhibitor were cloned by the dilution method. Seventeen hybridomas producing antibodies were isolated, four of which also recognized purified human collagenase inhibitor in the ELISA. Using a monoclonal antibody-Sepharose affinity column, we easily purified both bovine and human collagenase inhibitors to homogeneity. They showed the same mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, corresponding to a molecular mass of 32,000 daltons.

Elevated levels of human collagenase inhibitor in blister fluids of diverse etiology

Blister fluids from a variety of bullous disorders were examined for the presence of human collagenase inhibitor. A protein immunologically identical to the collagenase inhibitor produced by human skin fibroblasts was found in high concentrations within bullae of diverse etiologies. Levels of collagenase inhibitor in blister fluids ranged from 0.9-12.5 micrograms/ml, averaging 4.9 micrograms/ml. The mean values were 3- to 4-fold greater than those present in the sera of corresponding patients and exceeded plasma levels by 6- to 8-fold. The time course of collagenase inhibitor accumulation in blister fluid was studied using heat- and suction-induced bullae. The concentration in newly formed blisters was approximately 0.5 micrograms/ml, virtually identical to plasma inhibitor levels, and remained constant for approximately 4 h. Inhibitor concentrations then rose rapidly, reaching peak values of approximately 6 micrograms/ml after 48 h. We speculate that the role of this inhibitor in blister fluid involves the inhibitions of active proteinases within the bulla cavity and may occur to limit the extent of blister formation or to assist in wound repair.

Immunolocalization of collagenase and tissue inhibitor of metalloproteinases (TIMP) in hypertrophic scar tissue

Normal, mature and hypertrophic dermal scars were examined by indirect immunofluorescence for the presence of collagenase, tissue inhibitor of metalloproteinases (TIMP) and cathepsin D. Significant extracellular immunoprecipitation of both collagenase and TIMP were found in areas of all scars judged to be actively remodelling, whereas inactive areas were predominantly negative. TIMP was also present in endothelial cells of patent blood vessels, but found not to be present in the enlarged endothelial cells of occluded vessels. Negligible amounts of extracellular cathepsin D were found.

Rapid purification of tissue inhibitor of metalloproteinases from human plasma and identification as a gamma-serum protein

A rapid method is described for the purification of human tissue inhibitor of metalloproteinases (TIMP) from plasma which involves immuno-affinity chromatography and gel filtration. The purified plasma inhibitor is immunologically identical with the TIMP previously purified from human amniotic fluid, human synovial fluid and human fibroblast culture medium. It is proposed that this inhibitor is identical with the plasma inhibitor previously named 'B1 anticollagenase', although the plasma inhibitor was shown to migrate as a gamma-serum component.

Human fibroblast tissue inhibitor of metalloproteinases: glycosylation and function

The glycosylation of human fibroblast tissue inhibitor of metalloproteinases and procollagenase was examined in vivo using tunicamycin B2 and in vitro using Peptide: N-glycosidase F. In the presence of tunicamycin B2, unglycosylated inhibitor continues to be synthesized and secreted at normal or increased rates. The protein core of this collagenase inhibitor has an apparent Mr of 21,000 and possesses at least two oligosaccharide linkage sites as evidenced by the accumulation of a single 25,000 dalton intermediate. Collagenase inhibitor deglycosylated by Peptide: N-glycosidase also has an apparent molecular weight of 21,000 daltons; furthermore, deglycosylated inhibitor continues to block the activity of collagenase at a 1:1 molar stoichiometry and does not differ from the native glycoprotein in its resistance to tryptic degradation. Using these same two reagents, the characteristic doublet of human fibroblast procollagenase was found to result from glycosylation in the upper (60,000 dalton) form. Secretion of procollagenase was significantly inhibited in the presence of tunicamycin B2.

Activation of the endogenous metalloproteinase, gelatinase, by triggered human neutrophils

Triggered human neutrophils degraded denatured type I collagen (gelatin) by releasing and activating the latent metalloenzyme, gelatinase. The ability of the neutrophil to activate this enzyme was significantly, but not completely, inhibited by agents known to inhibit or scavenge chlorinated oxidants generated by the H2O2/myeloperoxidase/chloride system. A direct role for chlorinated oxidants in this process was confirmed by the ability of reagent HOCl to activate the latent enzyme in either the cell-free supernatant or in a highly purified state. Gelatinase activity was also expressed by triggered neutrophils isolated from patients with chronic granulomatous disease. The amount of gelatinolytic activity expressed by the patients' cells was similar to that released by normal neutrophils that were triggered in the presence of antioxidants. Thus, human neutrophils have the ability to activate gelatinase by either an HOCl-dependent process or an uncharacterized oxygen-independent process. The ability of the neutrophil to directly regulate this enzyme suggests an important role for the metalloproteinase in physiologic and pathophysiologic connective tissue metabolism.

Primary structure and cDNA cloning of human fibroblast collagenase inhibitor

We report the primary structure and cDNA cloning of human fibroblast collagenase inhibitor, a glycoprotein that appears to play a central role in modulating the activity of a number of metalloendoproteases of connective tissue origin including collagenase, gelatinase, and proteoglycanase. Secreted human fibroblast collagenase inhibitor was purified and subjected to automated Edman degradation. The secreted protein consists of 184 amino acid residues; it contains two sites of N-linked oligosaccharide linkage and six disulfide bonds. Synthetic oligonucleotide probes based on selected amino acid sequences of the inhibitor were used to screen a lambda gt10 cDNA library from a human fibroblast line. Two overlapping cDNA clones were characterized to determine the complete coding and noncoding sequences of the specific mRNA. The amino acid sequence deduced from the nucleotide sequence agrees with that determined by protein sequencing. One clone appears to contain the complete 5' end and, in addition, the cDNA sequence predicts a 23-amino acid leader peptide. The other clone represents the 3' end of the mature message and includes a short poly(A)+ tract. This 3' sequence is remarkably similar to a reported cDNA encoding part of the protein derived from mouse fibroblast poly(A)+ RNA. However, this inhibitor has no substantial homology with previously sequenced protease inhibitors.