Inactivation of tissue inhibitor of metalloproteinases by neutrophil elastase and other serine proteinases

The TIMP protein family: diverse roles in pathophysiology

The tissue inhibitors of matrix metalloproteinases (TIMPs) are a family of four matrisome proteins classically defined by their roles as the primary endogenous inhibitors of metalloproteinases (MPs). Their functions however are not limited to MP inhibition, with each family member harboring numerous MP-independent biological functions that play key roles in processes such as inflammation and apoptosis. Because of these multifaceted functions, TIMPs have been cited in diverse pathophysiological contexts. Herein, we provide a comprehensive overview of the MP-dependent and -independent roles of TIMPs across a range of pathological conditions. The potential therapeutic and biomarker applications of TIMPs in these disease contexts are also considered, highlighting the biomedical promise of this complex and often misunderstood protein family.

Tissue inhibitors of metalloproteinases are proteolytic targets of matrix metalloproteinase 9

Extracellular proteolysis and turnover are core processes of tissue homeostasis. The predominant matrix-degrading enzymes are members of the Matrix Metalloproteinase (MMP) family. MMPs extensively degrade core matrix components in addition to processing a range of other factors in the extracellular, plasma membrane, and intracellular compartments. The proteolytic activity of MMPs is modulated by the Tissue Inhibitors of Metalloproteinases (TIMPs), a family of four multi-functional matrisome proteins with extensively characterized MMP inhibitory functions. Thus, a well-regulated balance between MMP activity and TIMP levels has been described as critical for healthy tissue homeostasis, and this balance can be chronically disturbed in pathological processes. The relationship between MMPs and TIMPs is complex and lacks the constraints of a typical enzyme-inhibitor relationship due to secondary interactions between various MMPs (specifically gelatinases) and TIMP family members. We illustrate a new complexity in this system by describing how MMP9 can cleave members of the TIMP family when in molar excess. Proteolytic processing of TIMPs can generate functionally altered peptides with potentially novel attributes. We demonstrate here that all TIMPs are cleaved at their C-terminal tails by a molar excess of MMP9. This processing removes the N-glycosylation site for TIMP3 and prevents the TIMP2 interaction with latent proMMP2, a prerequisite for cell surface MMP14-mediated activation of proMMP2. TIMP2/4 are further cleaved producing ∼14 kDa N-terminal proteins linked to a smaller C-terminal domain through residual disulfide bridges. These cleaved TIMP2/4 complexes show perturbed MMP inhibitory activity, illustrating that MMP9 may bear a particularly prominent influence upon the TIMP:MMP balance in tissues.

Cut loose TIMP-1: an emerging cytokine in inflammation

Appreciation of the entire biological impact of an individual protein can be hampered by its original naming based on one function only. Tissue inhibitor of metalloproteinases-1 (TIMP-1), mostly known for its eponymous function to inhibit metalloproteinases, exhibits only a fraction of its cellular effects via this feature. Recently, TIMP-1 emerged as a potent cytokine acting via various cell-surface receptors, explaining a so-far under-appreciated role of TIMP-1-mediated signaling on immune cells. This, at least partly, resolved why elevated blood levels of TIMP-1 correlate with progression of numerous inflammatory diseases. Here, we emphasize the necessity of unbiased name-independent recognition of structure-function relationships to properly appreciate the biological potential of TIMP-1 and other cytokines in complex physiological processes such as inflammation.

The PDE4 Inhibitor Tanimilast Restrains the Tissue-Damaging Properties of Human Neutrophils

Neutrophils, the most abundant subset of leukocytes in the blood, play a pivotal role in host response against invading pathogens. However, in respiratory diseases, excessive infiltration and activation of neutrophils can lead to tissue damage. Tanimilast-international non-proprietary name of CHF6001—is a novel inhaled phosphodiesterase 4 (PDE4) inhibitor in advanced clinical development for the treatment of chronic obstructive pulmonary disease (COPD), a chronic inflammatory lung disease where neutrophilic inflammation plays a key pathological role. Human neutrophils from healthy donors were exposed to pro-inflammatory stimuli in the presence or absence of tanimilast and budesonide—a typical inhaled corticosteroid drug-to investigate the modulation of effector functions including adherence to endothelial cells, granule protein exocytosis, release of extracellular DNA traps, cytokine secretion, and cell survival. Tanimilast significantly decreased neutrophil-endothelium adhesion, degranulation, extracellular DNA traps casting, and cytokine secretion. In contrast, it promoted neutrophil survival by decreasing both spontaneous apoptosis and cell death in the presence of pro-survival factors. The present work suggests that tanimilast can alleviate the severe tissue damage caused by massive recruitment and activation of neutrophils in inflammatory diseases such as COPD.

Diagnostic usefulness of selected proteases and acute phase factors in patients with colorectal adenocarcinoma

BACKGROUND

Uncontrolled growth and loss of control over basic metabolic functions, leading to invasive proliferation and metastases, are the salient traits of malignant tumors in general and colorectal cancer in particular. Invasion and metastases hinder effective tumor treatment. While surgical techniques and radiotherapy can be used to remove tumor focus, only chemotherapy can eliminate dispersed neoplastic cells. However, the efficacy of the latter method is limited in the advanced stages of the disease. Therefore, recognition of the mechanisms involved in neoplastic cell spreading is indispensable for developing effective therapies.

AIM

To use a number of biomarkers involved in cancer progression and identify a panel that could be used for effective early diagnosis.

METHODS

We recruited 185 patients with colorectal adenocarcinoma (98 men, 87 women with median age 63). Thirty-five healthy controls were sex and age-matched. Dukes’ staging was as follows: A = 22, B = 52, C = 72, D = 39. We analyzed patients' blood serum before surgery. We determined: (1) Cathepsin B (CB) with Barrett's method (fluorogenic substrate); (2) Leukocytic elastase (LE) in a complex with alpha 1 trypsin inhibitor (AAT) using the immunoenzymatic MERCK test; (3) Total sialic acid (TSA) with the colorimetric periodate-resorcinol method; (4) Lipid-bound sialic acid (LASA) with the colorimetric Taut's method; and (5) The antitrypsin activity (ATA) employing the colorimetric test.

RESULTS

In patients, the values of the five biochemical parameters were as follows: CB = 16.1 ± 8.8 mU/L, LE = 875 ± 598 µg/L, TSA = 99 ± 31 mg%, LASA = 0.68 ± 0.33 mg%, and ATA = 3211 ± 1504 U/mL. Except for LASA, they were significantly greater than those of controls: CB = 11.4 ± 6.5 mU/L, LE = 379 ± 187 µg/L, TSA = 71.4 ± 15.1 mg%, LASA = 0.69 ± 0.28 mg%, and ATA = 2016 ± 690 U/mL. For CB and LASA, the differences between the four Dukes’ stages and controls were not statistically significant. The inter-stage differences for CB and LASA were also absent. The receiver operating characteristic (ROC) analysis revealed the potential diagnostic value of CB, TSA, and ATA. The area under ROC, sensitivity, and specificity for these three parameters were: 0.85, 72%, 90%; 0.75, 66%, 77%; and 0.77, 63%, 84%, respectively. The sensitivity and specificity for the three-parameter panel CB-TSA-ATA were equal to 88.2% and 100%, respectively.

CONCLUSION

The increased value of CB, TSA, and ATA parameters are associated with tumor biology, invasion, and metastasis of colorectal cancer. The presented evidence suggests the potential value of the CB-TSA-ATA biochemical marker panel in early diagnostics.

Sulfonated Nonsaccharide Heparin Mimetics Are Potent and Noncompetitive Inhibitors of Human Neutrophil Elastase

Human neutrophil elastase (HNE) is a serine protease that plays vital roles in inflammation, innate immune response, and tissue remodeling processes. HNE has been actively pursued as a drug target, particularly for the treatment of cardiopulmonary diseases. Although thousands of molecules have been reported to inhibit HNE, yet very few are being evaluated in early clinical trials, with sivelestat as the only approved HNE inhibitor. We report here a novel chemotype of sulfonated nonsaccharide heparin mimetics as potent and noncompetitive inhibitors of HNE. Using a chromogenic substrate hydrolysis assay, 14 sulfonated nonsaccharide heparin mimetics were tested for their inhibitory activity against HNE. Only 12 molecules inhibited HNE with IC₅₀ values of 0.22-88.3 μM. The inhibition of HNE by these molecules was salt-dependent. Interestingly, a specific hexa-sulfonated molecule inhibited HNE with an IC₅₀ value of 0.22 μM via noncompetitive mechanism, as demonstrated by Michaelis-Menten kinetics. The hexa-sulfonated derivative demonstrated at least 455-, 221-, 1590-, 21-, and 381-fold selectivity indices over other heparin-binding coagulation proteins including factors IIa, Xa, IXa, XIa, and FXIIIa, respectively. At the highest concentrations tested, the molecule also did not significantly inhibit other serine proteases of plasmin, trypsin, and chymotrypsin. Further supporting its selectivity, the molecule did not show heparin-like effects on clotting times of human plasma. The molecule also did not affect the proliferation of three cell lines at a concentration as high as 10 μM. Interestingly, the hexa-sulfonated molecule also inhibited cathepsin G with an IC₅₀ value of 0.57 μM alluding to a dual anti-inflammatory action. A computational approach was exploited to identify putative binding site(s) for this novel class of HNE inhibitors. Overall, the reported hexa-sulfonated nonsaccharide heparin mimetic serves as a new platform to develop potent, selective, and noncompetitive inhibitors of HNE for therapeutic purposes.

Progress in the mechanism and targeted drug therapy for COPD

Chronic obstructive pulmonary disease (COPD) is emphysema and/or chronic bronchitis characterised by long-term breathing problems and poor airflow. The prevalence of COPD has increased over the last decade and the drugs most commonly used to treat it, such as glucocorticoids and bronchodilators, have significant therapeutic effects; however, they also cause side effects, including infection and immunosuppression. Here we reviewed the pathogenesis and progression of COPD and elaborated on the effects and mechanisms of newly developed molecular targeted COPD therapeutic drugs. Among these new drugs, we focussed on thioredoxin (Trx). Trx effectively prevents the progression of COPD by regulating redox status and protease/anti-protease balance, blocking the NF-κB and MAPK signalling pathways, suppressing the activation and migration of inflammatory cells and the production of cytokines, inhibiting the synthesis and the activation of adhesion factors and growth factors, and controlling the cAMP-PKA and PI3K/Akt signalling pathways. The mechanism by which Trx affects COPD is different from glucocorticoid-based mechanisms which regulate the inflammatory reaction in association with suppressing immune responses. In addition, Trx also improves the insensitivity of COPD to steroids by inhibiting the production and internalisation of macrophage migration inhibitory factor (MIF). Taken together, these findings suggest that Trx may be the ideal drug for treating COPD.

Course of matrix metalloproteinase-1 and pulmonary oxygenation in acute respiratory distress syndrome caused by oral ingestion of large doses of oxadiazon/butachlor emulsion: a case report

Background

We treated a patient who developed acute respiratory distress syndrome following ingestion of oxadiazon/butachlor emulsion. In this case, we continuously measured matrix metalloproteinase-1 level, an enzyme that reduces the extracellular matrix in the lungs, and tissue inhibitors of metalloproteinase-1.

Case Presentation

A 50-year-old woman attempted suicide by ingesting approximately 300 mL of oxadiazon/butachlor emulsion. Respiratory disorders were observed upon admission, therefore tracheal intubation was performed, followed by artificial respiratory management (ventilator support). After that, her condition became complicated by acute respiratory distress syndrome, but it improved with intensive care management. Matrix metalloproteinase-1 level showed a course opposite to the partial pressure of arterial oxygen/percentage of inspired oxygen ratio, whereas the matrix metalloproteinase-1/tissue inhibitors of metalloproteinase-1 ratio changed in parallel with the partial pressure of arterial oxygen/percentage of inspired oxygen ratio.

Conclusion

The relationship between matrix metalloproteinase-1 and tissue inhibitors of metalloproteinase-1 was presumed to be important for the development of acute respiratory distress syndrome.

Functional disparities within the TIMP family in cancer: hints from molecular divergence

The members of the tissue inhibitor of metalloproteinase (TIMP) family (TIMP-1, 2, 3, 4) are prominently appreciated as natural inhibitors of cancer-promoting metalloproteinases. However, clinical and recent functional studies indicate that some of them correlate with bad prognosis and contribute to the progression of cancer and metastasis, pointing towards mechanisms beyond inhibition of cancer-promoting proteases. Indeed, it is increasingly recognized that TIMPs are multi-functional proteins mediating a variety of cellular effects including direct cell signaling. Our aim was to provide comprehensive information towards a better appreciation and understanding of the biological heterogeneity and complexity of the TIMPs in cancer. Comparison of all four members revealed distinct cancer-associated expression patterns and distinct prognostic impact including a clear correlation of TIMP-1 with bad prognosis for almost all cancer types. For the first time, we present the interactomes of all TIMPs regarding overlapping and non-overlapping interaction partners. Interestingly, the overlap was maximal for metalloproteinases (e.g., matrix metalloproteinase 1, 2, 3, 9) and decreased for non-protease molecules, especially cell surface receptors (e.g., CD63, overlapping only for TIMP-1 and 4; IGF-1R unique for TIMP-2; VEGFR2 unique for TIMP-3). Finally, we attempted to identify and summarize experimental evidence for common and unique structural traits of the four TIMPs on the basis of amino acid sequence and protein folding, which account for functional disparities. Altogether, the four TIMPs have to be appreciated as molecules with commonalities, but, more importantly, functional disparities, which need to be investigated further in the future, since those determine their distinct roles in cancer and metastasis.

The expression of matrix metalloproteinases and their inhibitors in corneal fibroblasts by alarmins from necrotic corneal epithelial cells

PURPOSE

Sterile ulceration is frequently observed in the cornea following persistent corneal epithelial damage. We examined the effect of alarmins released by necrotic corneal epithelial cells (HCE) on the production of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) by corneal fibroblasts.

METHODS

IL-1α and high-mobility group box 1 protein (HMGB1) released into the supernatant derived from necrotic HCE cells were measured with enzyme-linked immunosorbent assay (ELISA). MMPs and TIMPs produced by corneal fibroblasts, stimulated with the supernatant from necrotic HCE cells, were analyzed and measured with protein array and ELISA. To investigate dynamic expression of alarmins in the corneal epithelium, we used immunohistochemistry to observe the expression of human IL-1α in the corneal epithelium of human IL-1α Tg mice with or without cryopexy. We also investigated the expression of MMPs in corneal stroma of the mice treated with cryopexy, using RT-PCR.

RESULTS

We detected IL-1α and HMGB-1 in the supernatant of necrotic HCE cells. These supernatants increased the expression of MMP-3 and MMP-1, and decreased that of TIMP-1 and TIMP-2 in human corneal fibroblasts. Almost always these were inhibited by IL-1 receptor antagonist. Recombinant IL-1α increased the production MMP-3 and MMP-1 in corneal fibroblasts. After cryopexy of the epithelium of human IL-1α Tg mice, the expression of human IL-1α was recognized in the cytoplasm but not nucleus of epithelial cells. The level of MMP-3 and MMP-1 mRNAs was elevated in the corneal stroma in mice treated with cryopexy.

CONCLUSION

Alarmins, especially IL-1α, released from necrotic HCE cells may play an important role in the expression of MMPs and TIMPs by corneal fibroblast, resulting in sterile ulceration.

Targets of Neutrophil Influx and Weaponry: Therapeutic Opportunities for Chronic Obstructive Airway Disease

Neutrophils are important effector cells of antimicrobial immunity in an acute inflammatory response, with a primary role in the clearance of extracellular pathogens. However, in respiratory diseases such as asthma and chronic obstructive pulmonary disease (COPD), there is excessive infiltration and activation of neutrophils, subsequent production of reactive oxygen species, and release of serine proteases, matrix metalloproteinases, and myeloperoxidase—resulting in collateral damage as the cells infiltrate into the tissue. Increased neutrophil survival through dysregulated apoptosis facilitates continued release of neutrophil-derived mediators to perpetuate airway inflammation and tissue injury. Several target mechanisms have been investigated to address pathologic neutrophil biology and thereby provide a novel therapy for respiratory disease. These include neutrophil influx through inhibition of chemokine receptors CXCR2, CXCR1, and PI3Kγ signaling and neutrophil weaponry by protease inhibitors, targeting matrix metalloproteinases and neutrophil serine proteases. In addition, neutrophil function can be modulated using selective PI3Kδ inhibitors. This review highlights the latest advances in targeting neutrophils and their function, discusses the opportunities and risks of neutrophil inhibition, and explores how we might better develop future strategies to regulate neutrophil influx and function for respiratory diseases in dire need of novel effective therapies.

Role of Proteases in Lung Disease: A Brief Overview

Proteases play an important role in health and disease of the lung. In the normal lungs, proteases maintain their homeostatic functions that regulate processes like its regeneration and repair. Dysregulation of proteases–antiproteases balance is crucial in the manifestation of different types of lung diseases. Chronic inflammatory lung pathologies are associated with a marked increase in protease activities. Thus, in addition to protease activities, inhibition of anti-proteolytic control mechanisms are also important for effective microbial infection and inflammation in the lung. Herein, we briefly summarize the role of different proteases and to some extent antiproteases in regulating a variety of lung diseases.

Calcium-induced conformational changes of Thrombospondin-1 signature domain: implications for vascular disease

CONTEXT

Thrombospondin1 (TSP1) participates in numerous signaling pathways critical for vascular physiology and disease. The conserved signature domain of thrombospondin 1 (TSP1-Sig1) comprises three epidermal growth factor (EGF), 13 calcium-binding type 3 thrombospondin (T3) repeats, and one lectin-like module arranged in a stalk-wire-globe topology. TSP1 is known to be present in both calcium-replete (Holo-) and calcium-depleted (Apo-) state, each with distinct downstream signaling effects.

OBJECTIVE

To prepare a homology model of TSP1-Sig1 and investigate the effect of calcium on its dynamic structure and interactions.

METHODS

A homology model of Holo-TSP1-Sig1 was prepared with TSP2 as template in Swissmodel workspace. The Apo-form of the model was obtained by omitting the bound calcium ions from the homology model. Molecular dynamics (MD) simulation studies (100 ns) were performed on the Holo- and Apo- forms of TSP1 using Gromacs4.6.5.

RESULTS AND DISCUSSION

After simulation, Holo-TSP1-Sig1 showed significant reorientation at the interface of the EGF1-2 and EGF2-3 modules. The T3 wire is predicted to show the maximum mobility and deviation from the initial model. In Apo-TSP1-Sig1 model, the T3 repeats unfolded and formed coils with predicted increase in flexibility. Apo-TSP1-Sig1model also predicted the exposure of the binding sites for neutrophil elastase, integrin and fibroblast growth factor 2. We present a structural model and hypothesis for the role of TSP1-Sig1 interactions in the development of vascular disorders.

CONCLUSION

The simulated model of the fully calcium-loaded and calcium-depleted TSP1-Sig1 may enable the development of its interactions as a novel therapeutic target for the treatment of vascular diseases.

α1-Antitrypsin deficiency

α1-Antitrypsin deficiency (A1ATD) is an inherited disorder caused by mutations in SERPINA1, leading to liver and lung disease. It is not a rare disorder but frequently goes underdiagnosed or misdiagnosed as asthma, chronic obstructive pulmonary disease (COPD) or cryptogenic liver disease. The most frequent disease-associated mutations include the S allele and the Z allele of SERPINA1, which lead to the accumulation of misfolded α1-antitrypsin in hepatocytes, endoplasmic reticulum stress, low circulating levels of α1-antitrypsin and liver disease. Currently, there is no cure for severe liver disease and the only management option is liver transplantation when liver failure is life-threatening. A1ATD-associated lung disease predominately occurs in adults and is caused principally by inadequate protease inhibition. Treatment of A1ATD-associated lung disease includes standard therapies that are also used for the treatment of COPD, in addition to the use of augmentation therapy (that is, infusions of human plasma-derived, purified α1-antitrypsin). New therapies that target the misfolded α1-antitrypsin or attempt to correct the underlying genetic mutation are currently under development.

Development of a MALDI MS-based platform for early detection of acute kidney injury

PURPOSE

Septic acute kidney injury (AKI) is associated with poor outcome. This can partly be attributed to delayed diagnosis and incomplete understanding of the underlying pathophysiology. Our aim was to develop an early predictive test for AKI based on the analysis of urinary peptide biomarkers by MALDI-MS.

EXPERIMENTAL DESIGN

Urine samples from 95 patients with sepsis were analyzed by MALDI-MS. Marker search and multimarker model establishment were performed using the peptide profiles from 17 patients with existing or within the next 5 days developing AKI and 17 with no change in renal function. Replicates of urine sample pools from the AKI and non-AKI patient groups and normal controls were also included to select the analytically most robust AKI markers.

RESULTS

Thirty-nine urinary peptides were selected by cross-validated variable selection to generate a support vector machine multidimensional AKI classifier. Prognostic performance of the AKI classifier on an independent validation set including the remaining 61 patients of the study population (17 controls and 44 cases) was good with an area under the receiver operating characteristics curve of 0.82 and a sensitivity and specificity of 86% and 76%, respectively.

CONCLUSION AND CLINICAL RELEVANCE

A urinary peptide marker model detects onset of AKI with acceptable accuracy in septic patients. Such a platform can eventually be transferred to the clinic as fast MALDI-MS test format.

Antimicrobial proteins and peptides in human lung diseases: A friend and foe partnership with host proteases

Lung antimicrobial proteins and peptides (AMPs) are major sentinels of innate immunity by preventing microbial colonization and infection. Nevertheless bactericidal activity of AMPs against Gram-positive and Gram-negative bacteria is compromised in patients with chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF) and asthma. Evidence is accumulating that expression of harmful human serine proteases, matrix metalloproteases and cysteine cathepsins is markedely increased in these chronic lung diseases. The local imbalance between proteases and protease inhibitors compromises lung tissue integrity and function, by not only degrading extracellular matrix components, but also non-matrix proteins. Despite the fact that AMPs are somewhat resistant to proteolytic degradation, some human proteases cleave them efficiently and impair their antimicrobial potency. By contrast, certain AMPs may be effective as antiproteases. Host proteases participate in concert with bacterial proteases in the degradation of key innate immunity peptides/proteins and thus may play immunomodulatory activities during chronic lung diseases. In this context, the present review highlights the current knowledge and recent discoveries on the ability of host enzymes to interact with AMPs, providing a better understanding of the role of human proteases in innate host defense.

Gingival crevicular fluid levels of Matrix Metalloproteinase-1 (MMP-1) and Tissue Inhibitor of Metalloproteinase-1 (TIMP-1) in periodontal health and disease

BACKGROUND

Matrix Metalloproteinases (MMPs) are directly responsible for pathogenesis of periodontal diseases and their activity is regulated by Tissue Inhibitor of Metalloproteinases (TIMPs). This study was aimed to evaluate changes in gingival crevicular fluid (GCF) levels of MMP-1 and TIMP-1 in periodontal health and disease.

MATERIALS AND METHOD

Clinical parameters were recorded and GCF samples were collected from 30 subjects with chronic generalised periodontitis and 20 periodontally healthy subjects. Subjects with periodontitis underwent scaling and root planing (SRP). GCF samples were collected and clinical parameters were recorded again after 1 month of SRP. GCF levels of MMP-1 and TIMP-1 were detected by ELISA.

RESULTS

GCF levels of MMP-1 were significantly increased in subjects with periodontitis at baseline (P0) as compared to periodontally healthy subjects (C). GCF levels of MMP-1 reduced significantly in subjects with periodontitis after treatment (P1) as compared to P0. GCF levels of TIMP-1 were significantly reduced in P0 as compared to C. GCF levels of TIMP-1 increased significantly in P1 as compared to P0.

CONCLUSION

Substantial elevation in GCF levels of MMP-1 and reduction in TIMP-1 were found in periodontitis as compared to healthy subjects. GCF levels of MMP-1 and TIMP-1 improved significantly after treatment.

Influence of phase I periodontal therapy on levels of matrix metalloproteinase 1 and tissue inhibitor of metalloproteinase 1

BACKGROUND

Matrix metalloproteinase-1 (MMP-1) is a member of a family of enzymes that can degrade most extracellular matrix macromolecules. Extracellularly, MMPs are controlled by tissue inhibitors of metalloproteinases (TIMPs) and by mechanisms of pro-MMP activation. Levels of MMPs and TIMPs change during healing, inflammation, and normal tissue turnover. Herein we aimed to evaluate the levels of MMP-1 and TIMP-1 in gingival crevicular fluid (GCF) from periodontally healthy patients (control group) and chronic periodontitis patients before and after phase 1 therapy.

METHODS

In this study we examined 30 patients who had chronic periodontitis with probing depth sites ⩾5 mm and a clinical attachment level (CAL) ⩾5 mm. We included 30 periodontally healthy patients as a control. Clinical measurements such as plaque (PI) and gingival (GI) indices, papillary bleeding index (PBI), probing depths (PD), and CAL were recorded both before treatment (BT) and after phase I periodontal treatment (AT). Assays for MMP-1 and TIMP-1 were performed with an enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

All clinical parameters were significantly reduced at the post-therapy visit. MMP-1 levels were significantly higher in patients BT than the controls; however, the patients AT were not statistically different than the controls. TIMP-1 levels in patients BT were significantly lower than in the controls and significantly lower than patients AT. We observed a significant positive correlation between GCF volume and MMP-1 levels. Furthermore, TIMP-1 levels were significantly negatively correlated with both GCF volume and all clinical parameters.

CONCLUSIONS

We observed that as the extent of periodontal destruction increases, MMP-1 concentration increases and TIMP-1 concentration decreases in GCF. When chronic periodontitis patients were treated by scaling and root planing (SRP), the average MMP-1 concentrations decreased and TIMP-1 concentrations increased in GCF.

Gelatinase B/MMP-9 in Tumour Pathogenesis and Progression

Since its original identification as a leukocyte gelatinase/type V collagenase and tumour type IV collagenase, gelatinase B/matrix metalloproteinase (MMP)-9 is now recognised as playing a central role in many aspects of tumour progression. In this review, we relate current concepts concerning the many ways in which gelatinase B/MMP-9 influences tumour biology. Following a brief outline of the gelatinase B/MMP-9 gene and protein, we analyse the role(s) of gelatinase B/MMP-9 in different phases of the tumorigenic process, and compare the importance of gelatinase B/MMP-9 source in the carcinogenic process. What becomes apparent is the importance of inflammatory cell-derived gelatinase B/MMP-9 in tumour promotion, early progression and triggering of the "angiogenic switch", the integral relationship between inflammatory, stromal and tumour components with respect to gelatinase B/MMP-9 production and activation, and the fundamental role for gelatinase B/MMP-9 in the formation and maintenance of tumour stem cell and metastatic niches. It is also apparent that gelatinase B/MMP-9 plays important tumour suppressing functions, producing endogenous angiogenesis inhibitors, promoting inflammatory anti-tumour activity, and inducing apoptosis. The fundamental roles of gelatinase B/MMP-9 in cancer biology underpins the need for specific therapeutic inhibitors of gelatinase B/MMP-9 function, the use of which must take into account and substitute for tumour-suppressing gelatinase B/MMP-9 activity and also limit inhibition of physiological gelatinase B/MMP-9 function.

Comparison of Salivary TIMP-1 Levels in Periodontally Involved and Healthy Controls and the Response to Nonsurgical Periodontal Therapy

Background. Periodontal disease is a chronic inflammatory condition affecting the supporting structures of the dentition. Periodontal destruction is an outcome of the imbalance between matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases (TIMPs). We wanted to prove the hypothesis that salivary TIPM-1 level will vary in different people. A decrease in TIMP-1 level could make them more susceptible to periodontitis whereas a normal level could prevent increased tissue destruction thereby inhibiting the progression from gingivitis to periodontitis. This could probably pave the way for TIPM-1 to be a specific salivary biomarker and serve as a useful diagnostic and therapeutic tool in periodontitis. Methods. Whole unstimulated saliva of 2 ml was collected from twenty-five periodontally healthy and twenty-seven systemically healthy subjects with periodontitis. Clinical parameters recorded at baseline and reevaluated after four weeks in subjects with periodontitis following nonsurgical periodontal therapy were gingival index (GI), oral hygiene index-Simplified (OHI-S), probing pocket depth, and clinical attachment level (CAL). Salivary TIMP-1 levels in both were analyzed using a commercially available ELISA kit.

Metalloproteinases and their natural inhibitors in inflammation and immunity

Over the past 50 years, steady growth in the field of metalloproteinase biology has shown that the degradation of extracellular matrix components represents only a fraction of the functions performed by these enzymes and has highlighted their fundamental roles in immunity. Metalloproteinases regulate aspects of immune cell development, effector function, migration and ligand-receptor interactions. They carry out ectodomain shedding of cytokines and their cognate receptors. Together with their endogenous inhibitors TIMPs (tissue inhibitor of metalloproteinases), these enzymes regulate signalling downstream of the tumour necrosis factor receptor and the interleukin-6 receptor, as well as that downstream of the epidermal growth factor receptor and Notch, which are all pertinent for inflammatory responses. This Review discusses the metalloproteinase family as a crucial component in immune cell development and function.

Neutrophil-derived Oxidants and Proteinases as Immunomodulatory Mediators in Inflammation

Neutrophils generate potent microbicidal molecules via the oxygen-dependent pathway, leading to the generation of reactive oxygen intermediates (ROI), and via the non-oxygen dependent pathway, consisting in the release of serine proteinases and metalloproteinases stored in granules. Over the past years, the concept has emerged that both ROI and proteinases can be viewed as mediators able to modulate neutrophil responses as well as the whole inflammatory process. This is well illustrated by the oxidative regulation of proteinase activity showing that oxidants and proteinases acts is concert to optimize the microbicidal activity and to damage host tissues. ROI and proteinases can modify the activity of several proteins involved in the control of inflammatory process. Among them, tumour necrosis factor-α and interleukin-8, are elective targets for such a modulation. Moreover, ROI and proteinases are also able to modulate the adhesion process of neutrophils to endothelial cells, which is a critical step in the inflammatory process.

Susceptibility of lung epithelium to neutrophil elastase: protection by native inhibitors

The development of emphysema is thought to be due to an imbalance of proteases (especially neutrophil elastase [NE]) and antiproteases with loosening of the respiratory epithelium as an early event. We investigated the effect of NE on respiratory epithelial cell adherence in vitro , in the presence of varying concentrations and combinations of native inhibitors, α-1-proteinase inhibitor (PI) and secretory leukoprotease inhibitor (SLPI). SLPI was two to 12 times more effective than PI at preventing the effects of NE, especially when enzyme:inhibitor ratios were almost equivalent. Even when the concentration of SLPI was only 10% of the total (as in normal peripheral lung secretions), it gave greater protection than PI alone. This suggests that SLPI plays an important role in controlling neutrophil elastaseinduced inflammation and tissue damage.

Brain distribution and elimination of recombinant human TIMP-1 after cerebral ischemia and reperfusion in rats

OBJECTIVE

To investigate recombinant human TIMP-1 ((125)I-rhTIMP-1) half-life in blood and its distribution in rat brain tissue after cerebral ischemia/reperfusion as part of a therapeutic development paradigm.

METHOD

A suture model of the middle cerebral artery occlusion was used. (125)I-labeled rhTIMP-1 at 60 μg/kg (11.23 μCi/μg) was administered to rats intravenously at the beginning of reperfusion. Blood and brain tissue were collected. The radioactivity was detected with a gamma counter and analyzed by autoradiography.

RESULTS

The blood half-life T(1/2) of (125)I-rhTIMP-1 was 42.2 hours. Thirty minutes after (125)I-rhTIMP-1 administration, an increased accumulation of (125)I-rhTIMP-1 in the ischemic hemisphere was observed. The maximum brain tissue concentration C(max) was 26.1 ng/g at 1.5 hours in the striatum and 13.9 ng/g at 5 hours in the cortex when the uptake percentage of brain tissue to blood was 6.1±0.4 and 6.7±2.1%, respectively. The cortex and striatum elimination half-lives T(1/2) were 45.3 and 39.2 hours, respectively. Electrophoretic analysis of ischemic samples for (125)I-rhTIMP-1 showed a clear 28 kDa band 1.5 hours after (125)I-rhTIMP-1 administration in the cortex and striatum. The intensity of the 28 kDa band decreased after 3.0 hours of the administration. Some (125)I-rhTIMP-1 maintained its molecular integrity for 8.5 hours in ischemic striatum after reperfusion.

DISCUSSION

(125)I-labeled rhTIMP-1 was distributed quickly into ischemic brain tissue and had a slow elimination in both blood and brain tissue. These results, along with other studies suggesting therapeutic benefits, will aid in the development of TIMP-1 for protecting ischemic stroke.

SLPI and trappin-2 as therapeutic agents to target airway serine proteases in inflammatory lung diseases: current and future directions

It is now clear that NSPs (neutrophil serine proteases), including elastase, Pr3 (proteinase 3) and CatG (cathepsin G) are major pathogenic determinants in chronic inflammatory disorders of the lungs. Two unglycosylated natural protease inhibitors, SLPI (secretory leucocyte protease inhibitor) and elafin, and its precursor trappin-2 that are found in the lungs, have therapeutic potential for reducing the protease-induced inflammatory response. This review examines the multifaceted roles of SLPI and elafin/trappin-2 in the context of their possible use as inhaled drugs for treating chronic lung diseases such as CF (cystic fibrosis) and COPD (chronic obstructive pulmonary disease).

Ulinastatin, a urinary trypsin inhibitor, for the initial treatment of patients with Kawasaki disease: a retrospective study

BACKGROUND

Markedly activated neutrophils or higher plasma levels of neutrophil elastase are involved in the poor response to intravenous immunoglobulin (IVIG) and the formation of coronary artery lesions (CAL) in patients with acute Kawasaki disease. We hypothesized that ulinastatin (UTI), by both direct and indirect suppression of neutrophils, would reduce the occurrence of CAL.

METHODS AND RESULTS

We retrospectively analyzed the clinical records of patients with Kawasaki disease between 1998 and 2009. Three hundred sixty-nine patients were treated with a combination of UTI, aspirin, and IVIG as an initial treatment (UTI group), and 1178 were treated with a conventional initial treatment, and IVIG with aspirin (control group). The baseline characteristics did not demonstrate notable differences between the two groups. The occurrence of CAL was significantly lower in the UTI group than in the control group (3% versus 7%; crude odds ratio [OR], 0.46; 95% confidence interval [CI], 0.25-0.86; P=0.01). The OR adjusted for sex, Gunma score (the predictive score for IVIG unresponsiveness), and dosage of initial IVIG (1 or 2 g/kg) was 0.32 (95% CI, 0.17-0.60; P<0.001). In addition, most CAL occurred in patients requiring additional rescue treatment and the proportion of those patients was significantly lower in the UTI group than in the control group (13% versus 22%; crude OR, 0.52; 95% CI, 0.38-0.73; P<0.001). The adjusted OR was 0.30 (95% CI, 0.20-0.44; P<0.001).

CONCLUSIONS

UTI was associated with fewer patients requiring additional rescue treatment and reduction of CAL in this retrospective study.

Role of matrix metalloproteinase-3 in neurodegeneration

Matrix metalloproteinase-3 (MMP-3) is a member of the class of zinc-dependent proteases known to degrade the extracellular matrix. MMP-3 activity is regulated at three different levels: gene expression, proteolytic activation of the zymogen, and inhibition by the endogenous tissue inhibitors of metalloproteinase. A line of evidence indicates a role of MMP-3 in neurodegeneration. In neuronal cells, MMP-3 expression is increased in response to cell stress, and the cleaved, active MMP-3 participates in apoptotic signaling. In the extracellular space, MMP-3 triggers microglia to produce proinflammatory and cytotoxic molecules as well as MMP-3, which in turn contribute to neuronal damage. MMP-3 is increased in various experimental models of Parkinson's disease that are produced by selective toxins and by inflammagen, and the neuronal death is attenuated by various ways that inhibit MMP-3. α-Synuclein, whose gene mutations are associated with familial forms of Parkinson's disease, is proteolyzed by MMP-3. Contribution of MMP-3 toward the pathogenesis of Alzheimer's disease and other neurodegenerative diseases has also been suggested. Thus, modulation of MMP-3 expression and/or activity could be of therapeutic value for neurodegenerative diseases.

Human neutrophil elastase-mediated cleavage sites of MMP-9 and TIMP-1: implications to cystic fibrosis proteolytic dysfunction

Cystic fibrosis (CF) is a lethal genetic disorder characterized by airway remodeling and inflammation, leading to premature death. Recent evidence suggests the importance of protease activity in CF pathogenesis. One prominent protease, matrix metalloprotease (MMP)-9, demonstrates increased activity in CF individuals undergoing acute pulmonary exacerbation. This is thought to be mediated by both direct MMP-9 activation and the degradation of its natural inhibitor, tissue inhibitor of metalloprotease-1 (TIMP-1). To examine if this relationship exists in nonexacerbating CF individuals, we examined protease activity in sputum from these individuals compared with nondisease controls. We demonstrated increased gelatinolytic activity in CF sputum. These samples had elevated human neutrophil elastase (HNE) levels which correlated with an increased MMP-9/TIMP-1 ratio. To determine if HNE could discretely cleave and activate MMP-9, these enzymes were coincubated and two specific cleavage sites, between Valine(38) and Alanine(39), and between Alanine (39) and glutamic acid(40) were observed. These sites corresponded with appropriate molecular weight for the activated MMP-9 isoform in CF sputum. Using N-terminal sequencing of cleavage fragments obtained with TIMP-1 incubation with HNE, we confirmed the TIMP-1 cleavage site for HNE is at Valine(69)-Cysteine(70). We also show for the first time that human neutrophils were capable of degrading TIMP-1 ex vivo and that a 16 kDa TIMP-1 fragment was identified in CF sputum, consistent with the expected cleavage of TIMP-1 by HNE. These results demonstrate increased MMP-9 activity in stable CF lung disease, and the presence of specific protease products in CF sputum highlights that HNE-mediated activity plays a role in this dysregulation.

Roles for proteinases in the pathogenesis of chronic obstructive pulmonary disease

Since the early 1960s, a compelling body of evidence has accumulated to show that proteinases play critical roles in airspace enlargement in chronic obstructive pulmonary disease (COPD). However, until recently the causative enzymes and their exact roles in pathologic processes in COPD have not been clear. Recent studies of gene-targeted mice in murine models of COPD have confirmed roles for proteinases not only in airspace enlargement, but also in airway pathologies in COPD. These studies have also shed light on the specific proteinases involved in COPD pathogenesis, and the mechanisms by which these proteinases injure the lung. They have also identified important interactions between different classes of proteinases, and between proteinases and other molecules that amplify lung inflammation and injury. This review will discuss the biology of proteinases and the mechanisms by which they contribute to the pathogenesis of COPD. In addition, I will discuss the potential of proteinase inhibitors and anti-inflammatory drugs as new treatment strategies for COPD patients.

Targeting neutrophil elastase in cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is a lethal hereditary disease characterised by neutrophil-dominated lung inflammation. These abundant neutrophils produce neutrophil elastase (NE), a destructive serine protease that has direct actions on extracellular matrix proteins and has a role in the host response to inflammation and infection.

OBJECTIVE

This review examines the prospect of developing novel therapies for CF by targeting NE. The authors explore the functions of NE and of naturally-occurring and synthetic NE inhibitors.

METHODS

A literature search was conducted exploring the functions of NE and inhibitors of NE; naturally occurring and synthetic.

CONCLUSIONS

Targeting NE in CF offers therapeutic potential, but optimal inhibitors that can be delivered safely and effectively to the lung are still under development.

Targeting lung inflammation: novel therapies for the treatment of COPD

Chronic obstructive pulmonary disease (COPD) is a global health problem. As understanding of pathology of COPD has increased it has been established that COPD is associated with the progressive pulmonary inflammation and destruction of lung parenchyma (emphysema) that relate to disease severity. Therefore, it is anticipated that drugs that reduce pulmonary inflammation will provide effective, disease modifying therapy for COPD. Several specific therapies are directed against the influx of inflammatory cells into the airways and lung parenchyma that occurs in COPD; these include agents directed against cytokines and chemokines. Broad-range anti-inflammatory drugs are now in phase III development for COPD; they include inhibitors of phosphodiesterase 4 (PDE4). Other drugs that inhibit cell signaling include inhibitors of p38 mitogen-activated protein kinase (MAPK), nuclear factor-κB (NF-κB), and phosphoinositide-3-kinase (PI3K). There is also a search for inhibitors of proteinases and matrix metalloproteinases (MMPs) to prevent lung destruction and the development of emphysema. This review highlights studies on novel or potential anti-inflammatory agents that might be considered in the development of new future therapies for COPD.

Reperfusion activates metalloproteinases that contribute to neurovascular injury

In this study, we examine the effects of reperfusion on the activation of matrix metalloproteinase (MMP) and assess the relationship between MMP activation during reperfusion and neurovascular injury. Ischemia was produced using suture-induced middle cerebral artery occlusion in rats. The MMP activation was examined with in situ and gel zymography. Injury to cerebral endothelial cells and basal lamina was assessed using endothelial barrier antigen (EBA) and collagen IV immunohistochemistry. Injury to neurons and glial cells was assessed using Cresyl violet staining. These were examined at 3 h after reperfusion (8 h after initiation of ischemia) and compared with permanent ischemia at the same time points to assess the effects of reperfusion. A broad-spectrum MMP inhibitor, AHA (p-aminobenzoyl-Gly-Pro-D-Leu-D-Ala-hydroxamate, 50 mg/kg intravenously) was administered 30 min before reperfusion to assess the roles of MMPs in activating gelatinolytic enzymes and in reperfusion-induced injury. We found that reperfusion accelerated and potentiated MMP-9 and MMP-2 activation and injury to EBA and collagen IV immunopositive microvasculature and to neurons and glial cells in ischemic cortex and striatum relative to permanent ischemia. Administering AHA 30 min before reperfusion decreased MMP-9 activation and neurovascular injury in ischemic cerebral cortex.

Solution structure of inhibitor-free human metalloelastase (MMP-12) indicates an internal conformational adjustment

Macrophage metalloelastase or matrix metalloproteinase-12 (MMP-12) appears to exacerbate atherosclerosis, emphysema, aortic aneurysm, rheumatoid arthritis, and inflammatory bowel disease. An inactivating E219A mutation, validated by crystallography and NMR spectra, prevents autolysis of MMP-12 and allows us to determine its NMR structure without an inhibitor. The structural ensemble of the catalytic domain without an inhibitor is based on 2813 nuclear Overhauser effects (NOEs) and has an average RMSD to the mean structure of 0.25 A for the backbone and 0.61 A for all heavy atoms for residues Trp109-Gly263. Compared to crystal structures of MMP-12, helix B (hB) at the active site is unexpectedly more deeply recessed under the beta-sheet. This opens a pocket between hB and beta-strand IV in the active-site cleft. Both hB and an internal cavity are shifted toward beta-strand I, beta-strand III, and helix A on the back side of the protease. About 25 internal NOE contacts distinguish the inhibitor-free solution structure and indicate hB's greater depth and proximity to the sheet and helix A. Line broadening and multiplicity of amide proton NMR peaks from hB are consistent with hB undergoing a slow conformational exchange among subtly different environments. Inhibitor-binding-induced perturbations of the NMR spectra of MMP-1 and MMP-3 map to similar locations across MMP-12 and encompass the internal conformational adjustments. Evolutionary trace analysis suggests a functionally important network of residues that encompasses most of the locations adjusting in conformation, including 18 residues with NOE contacts unique to inhibitor-free MMP-12. The conformational change, sequence analysis, and inhibitor perturbations of NMR spectra agree on the network they identify between structural scaffold and the active site of MMPs.

Multifaceted roles of human elafin and secretory leukocyte proteinase inhibitor (SLPI), two serine protease inhibitors of the chelonianin family

Elafin and SLPI are low-molecular weight proteins that were first identified as protease inhibitors in mucous fluids including lung secretions, where they help control excessive proteolysis due to neutrophil serine proteases (elastase, proteinase 3 and cathepsin G). Elafin and SLPI are structurally related in that both have a fold with a four-disulfide core or whey acidic protein (WAP) domain responsible for inhibiting proteases. Elafin is derived from a precursor, trappin-2 or pre-elafin, by proteolysis. Trappin-2, which is itself a protease inhibitor, has a unique N-terminal domain that enables it to become cross-linked to extracellular matrix proteins by transglutaminase(s). SLPI and elafin/trappin-2 are attractive candidates as therapeutic molecules for inhibiting neutrophil serine proteases in inflammatory lung diseases. Hence, they have become the WAP proteins most studied over the last decade. This review focuses on recent findings revealing that SLPI and elafin/trappin-2 have many biological functions as diverse as anti-bacterial, anti-fungal, anti-viral, anti-inflammatory and immuno-modulatory functions, in addition to their well-recognized role as protease inhibitors.

Matrix metalloprotease-9 dysregulation in lower airway secretions of cystic fibrosis patients

Matrix metalloproteases (MMPs) are proteolytic enzymes that regulate extracellular matrix turnover and aid in restoring tissue architecture following injury. There is an emerging role for extracellular matrix destruction in the pathogenesis of chronic neutrophilic lung diseases. In this study, we examined the expression and activity profiles of MMPs in lower airway secretions from cystic fibrosis (CF) patients, patients with acute respiratory failure (ARF), and normal controls. A discrete repertoire of MMP isoforms was found in the CF samples, with robust MMP-9 expression compared with normal controls and ARF. CF samples possessed increased levels of active MMP-9, as well as decreased amounts of tissue inhibitor of metalloprotease-1 (TIMP-1), a natural inhibitor of MMP-9. The CF inpatient samples demonstrated fully active MMP-9 activity compared with CF outpatients, ARF, and normal controls. CF samples also demonstrated increased human neutrophil elastase (HNE) levels compared with ARF and normal controls. To examine potential mechanisms for the protease dysregulation seen in the CF clinical samples, in vitro studies demonstrated that HNE could activate pro-MMP-9 and also degrade TIMP-1; this HNE-based activation, however, was not seen with MMP-8. A strong correlation was seen between HNE and MMP-9 activity in CF inpatient samples. Finally, the dysregulated MMP-9 activity seen in CF inpatient sputum samples could be significantly reduced by the use of MMP-9 inhibitors. Collectively, these findings further emphasize the proposed protease/antiprotease imbalance in chronic neutrophilic lung disease, providing a potential mechanism contributing to this proteolytic dysregulation.

Elastin-elastases and inflamm-aging

Degradation of elastin, the main amorphous component of elastic fibers, by elastases belonging to the serine, metallo, or cysteine families leads to the generation of elastin fragments, designated as elastokines in keeping with their cytokine-like properties. Generation of elastokines from one of the longest lived protein in human might represent a strong tissue repair signal. Indeed, they (1) exhibit potent chemotactic activity for leukocytes, (2) stimulate fibroblast and smooth muscle cell proliferation, and (3) display proangiogenic activity as potent as VEGF. However, continuous exposure of cells to these matrikines, through increased elastase(s) expression with age, can contribute to the formation of a chronic inflammatory state, that is, inflamm-aging. Importantly, binding of elastokines to S-Gal, their cognate receptor, proved to stimulate matrix metalloproteinase expression in normal and cancer cells. Besides, these elastin fragments can polarize lymphocytes toward a Th-1 response or induce an osteogenic response in smooth muscle cells, and arterial wall calcification. In this chapter, emphasis will be made on the contribution of elastokines on the genesis of age-related arterial wall diseases, particularly abdominal aortic aneurysms (AAAs). An elastokine theory of AAAs progression will be proposed. Age is one main risk factor of cancer incidence and development. The myriad of biological effects exerted by elastokines on stromal and inflammatory cells led us to hypothesize that they might be main actors in elaborating a favorable cancerization field in melanoma; for instance these peptides could catalyze the vertical growth phase transition in melanoma through increased expression of gelatinase A and membrane-type 1 matrix metalloproteinase.

The pathophysiology of coronary artery aneurysms in Kawasaki disease: role of matrix metalloproteinases

Kawasaki disease is an acute inflammatory syndrome that takes the form of systemic vasculitis, and predominantly affects children. Important complications of this disease are coronary artery dilation and aneurysm formation. Recent studies indicate that Kawasaki disease patients have elevated expression, activity, or protein levels of matrix metalloproteinases (MMPs), and suggest that imbalances in MMPs or MMP/tissue inhibitor of MMP (TIMP) play important pathophysiological roles in the development of coronary artery lesions in this disease. However, it remains unclear whether MMP activities at the site of coronary artery lesions are indeed increased. Further studies on the effects of MMP inhibition on coronary outcome are needed to define the roles of MMPs and TIMPs in the formation of coronary artery lesions in Kawasaki disease; findings of such studies may support the use of MMP inhibitors for the prevention of coronary artery complications in patients with this disease.

Elastolysis induces collagenolysis in a gingival lamina propria model

Elastin peptides were previously reported to increase MMP expression in several cell types. We found binding of these peptides to their receptors led to enhanced MMP-3 and MMP-1 expression, but not activation, in human gingival fibroblasts cultured on plastic dishes. We hypothesized that these peptides, in a more physiological environment, might additionally trigger an MMP-3/MMP-1 activation cascade, leading to matrix lysis, as occurs in periodontitis. To test this hypothesis, we used contracted and attached lattices as gingival lamina propria equivalents. In such 3D models, supplementation of elastin peptides and plasminogen triggered an MMP-3/MMP-1 activation cascade and significant down-regulation of TIMPs production, further leading to intense collagen degradation. We propose that elastolysis, as occurs in periodontitis, potentiates collagenolysis, thus promoting disease progression.

Differential expression of MMPs and TIMPs in moderate and severe heart failure in a transgenic model

BACKGROUND

Altered expression of matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) accompanies the development of heart failure (HF). However, changes in MMP and TIMP protein levels or activity during the progression from compensated to decompensated failure remains incompletely examined.

METHODS AND RESULTS

Transgenic mice (Tg) with cardiac-specific overexpression of tumor necrosis factor-alpha (TNF1.6) develop a sex-related, progressive cardiac dilation and HF. Echocardiographic measures were used to categorize HF severity in male (M) and female (F) Tg and wild-type (WT) mice between 4 and 50 weeks of age. Cardiac TIMPs-1, TIMPs-2, and MMP-3 (enzyme-linked immunosorbent assay), and potential (APMA-activated) MMP-9 activity were measured at similar ages. In situ zymography assessed tissue gelatinase activity. Systolic function, ventricular dimensions, and presence of pleural effusions identified severe HF in younger M Tg mice (by 18 weeks) and older F Tg (>34 weeks). Regardless of age, sex, or HF severity, Tg mice expressed significantly more TIMP-1 (Tg 119-193 pg/mg vs. WT 13-24 pg/mg, P < .001) and potential MMP-9 activity (Tg 0.41-0.58 ng/mg vs. WT 0.015-0.028 ng/mg, P < .002). M Tg expressed elevated MMP-3 (4 weeks, 0.16 +/- 0.1 ng/mg protein vs. WT 0.04 +/- 0.01 ng/mg, P < .003), which increased with age and HF severity (18 weeks, 0.51 +/- 0.3 ng/mg P < .01). F Tg showed no increase in MMP-3 at 4 weeks but a progressive increase with age and HF severity (18 weeks 0.09 +/- 0.04 ng/mg, P < .02 vs. Tg M or WT; 34 weeks 0.13 +/- 0.02 ng/mg, P < .001 vs. WT). To test the hypothesis that increased MMP-3 may differentially activate MMP-9 in M Tg, in situ zymography was performed and revealed a significant increase in gelatinase activity in M Tg mice relative to both WT and F Tg.

CONCLUSION

MMP-3 may regulate activation of MMP-9/gelatinase, the progression of cardiac remodeling, and development of decompensated heart failure.

Inflammation and cardiac remodeling during viral myocarditis

Acute viral myocarditis is the main cause of cardiac failure in young patients and accounts for up to 60% of "idiopathic" dilated cardiomyopathy. The clinical course of viral myocarditis is mostly insidious with limited cardiac inflammation and dysfunction. However, overwhelming inflammation may occur in a subset of patients, leading to fulminant cardiac injury, whereas others develop chronic heart failure due to autoimmune myocarditis. Today, little effective treatment exists for patients, apart from general supportive therapy and antifailure regimens. Urokinase-type plasminogen activator (u-PA) and matrix metalloproteinases (MMP) have been implicated in cardiac inflammation, matrix remodeling, and wound healing after cardiac injury. The present review will assess the mechanism by which these proteinases mediate cardiac dilatation, fibrosis, and dysfunction after cardiac stress or injury, in order to understand how inhibition of proteinases may provide a novel therapeutic tool to prevent cardiac dilatation and failure during viral myocarditis.

Thrombin and TNF-alpha/IL-1beta synergistically induce fibroblast-mediated collagen gel degradation

Degradation of preexisting and newly synthesized extracellular matrix is thought to play an important role in tissue remodeling. The current study evaluated whether thrombin and TNF-alpha/IL-1beta could collaboratively induce collagen degradation by human fetal lung fibroblasts (HFL-1) and adult bronchial fibroblasts cultured in three-dimensional collagen gels. TNF-alpha/IL-1beta alone induced production of matrix metalloproteinases (MMPs)-1, -3, and -9, which were released in latent form. With the addition of thrombin, the latent MMPs were converted into active forms and this resulted in collagen gel degradation. Part of the activation of MMPs by thrombin resulted from direct activation of MMP-1, MMP-2, MMP-3, and MMP-9 in the absence of cells. In addition, tissue inhibitor of metalloproteinase-1 production was inhibited by the combination of thrombin and TNF-alpha/IL-1beta. These results suggest that thrombin and TNF-alpha/IL-1beta synergize to induce degradation of three-dimensional collagen gels through increasing the production and activation of MMPs, and that this effect is mediated through both direct activation of MMPs by thrombin and indirectly by thrombin activation of fibroblasts. Through such mechanisms, thrombin could contribute to many chronic lung disorders characterized by tissue remodeling.

Pathogenic aspects of cutaneous photoaging

Chronic exposure to solar ultraviolet irradiation can result in wrinkle formation in many individuals. Wrinkling appears to be the conclusion of mechanisms that result in decreased synthesis of extracellular matrix molecules within the dermis, accompanied by increased remodeling of the matrix by specific endopeptidases (matrix metalloproteinases) and proteases (originating from infiltrating cells of the immune system). In this review, we discuss the changes that occur in the extracellular matrix of photoaged skin and the mechanisms by which they are modulated.

Leukocyte-derived matrix metalloproteinase-9 mediates blood-brain barrier breakdown and is proinflammatory after transient focal cerebral ischemia

Results of recent studies reveal vascular and neuroprotective effects of matrix metalloproteinase-9 (MMP-9) inhibition and MMP-9 gene deletion in experimental stroke. However, the cellular source of MMP-9 produced in the ischemic brain and the mechanistic basis of MMP-9-mediated brain injury require elucidation. In the present study, we used MMP-9−/−mice and chimeric knockouts lacking either MMP-9 in leukocytes or in resident brain cells to test the hypothesis that MMP-9 released from leukocytes recruited to the brain during postischemic reperfusion contributes to this injury phenotype. We also tested the hypothesis that MMP-9 promotes leukocyte recruitment to the ischemic brain and thus is proinflammatory. The extent of blood-brain barrier (BBB) breakdown, the neurological deficit, and the volume of infarction resulting from transient focal stroke were abrogated to a similar extent in MMP-9−/−mice and in chimeras lacking leukocytic MMP-9 but not in chimeras with MMP-9-containing leukocytes. Zymography and Western blot analysis from these chimeras confirmed that the elevated MMP-9 expression in the brain at 24 h of reperfusion is derived largely from leukocytes. MMP-9−/−mice exhibited a reduction in leukocyte-endothelial adherence and a reduction in the number of neutrophils plugging capillaries and infiltrating the ischemic brain during reperfusion; microvessel immunopositivity for collagen IV was also preserved in these animals. These latter results document proinflammatory actions of MMP-9 in the ischemic brain. Overall, our findings implicate leukocytes, most likely neutrophils, as a key cellular source of MMP-9, which, in turn, promotes leukocyte recruitment, causes BBB breakdown secondary to microvascular basal lamina proteolysis, and ultimately contributes to neuronal injury after transient focal stroke.

Matrix metalloproteinases in cerebrovascular diseases

Matrix metalloproteinases are important factors for tissue remodelling and are activated during several physiological and pathological conditions, including cerebrovascular diseases. We give an overview of the structure, production and physiological effects of these widely distributed proteases and describe the genetic background and regulation pathways. In particular, we discuss the role of matrix metalloproteinases in vascular remodelling concerning ischaemic stroke, brain haemorrhage, vascular dementia, carotid artery plaques and cerebral aneurysms.

Induced sputum matrix metalloproteinase-9 correlates with lung function and airway inflammation in children with cystic fibrosis

Matrix metalloproteinases (MMPs) degrade extracellular matrix and are implicated in causing airway damage in chronic inflammatory lung diseases, including cystic fibrosis (CF). Our primary objective was to examine the relationship between matrix metalloproteinase-9 (MMP-9) and pulmonary function, as measured by forced expiratory volume in 1 sec (FEV1), in children with CF. We measured MMP-9 and its natural tissue inhibitor of metalloproteinase-1 (TIMP-1) in induced sputum from 18 clinically stable CF children with normal to mildly abnormal lung function and 7 healthy control children. Measures of airway inflammation from induced sputum included cell counts and differentials, interleukin-8 (IL-8), neutrophil elastase, MMP-9, and TIMP-1. Infection was assessed through quantitative bacterial counts. Induced sputum levels of MMP-9 and TIMP-1 were significantly increased in children with CF compared with healthy controls. Also, the MMP-9/TIMP-1 molar ratio was higher in the CF group. Among CF children, there was a significant inverse relationship between MMP-9 and FEV1. In addition, sputum MMP-9 and TIMP-1 concentrations significantly correlated with total white cells and neutrophils, IL-8, and neutrophil elastase. Neither MMP-9 nor TIMP-1 correlated with airway infection. We conclude that clinically stable CF children with normal to mildly abnormal lung function have an increased burden of MMP-9 in their airways. The observed relationships of MMP-9 with lung function and other measures of airway inflammation suggest that this enzyme may be a useful marker of airway injury and airflow obstruction in persons with CF.