Inhibition Of Gelatinase Activity Research Articles

The role of endogenous H2S formation in reversible remodeling of lung tissue during hibernation in the Syrian hamster

During hibernation, small mammals alternate between periods of metabolic suppression and low body temperature ('torpor') and periods of full metabolic recovery with euthermic temperatures ('arousal'). Previously, we demonstrated marked structural remodeling of the lung during torpor, which is rapidly reversed during arousal. We also found that cooling of hamster cells increased endogenous production of H(2)S through the enzyme cystathionine-β-synthase (CBS). H(2)S suppresses the immune response and increases deposition of collagen. Therefore, we examined inflammatory markers and matrix metalloproteinase (MMP) activity in relation to CBS expression and H(2)S levels in lungs of euthermic and hibernating Syrian hamsters. Lung remodeling during torpor was confirmed by a strong increase in both collagenous and non-collagenous hydroxyproline content. The number of leukocytes in lung was unchanged in any phase of hibernation, while adhesion molecules VCAM-1 and ICAM-1, and the inflammatory marker NF-κB (P65) were modestly upregulated in torpor. Gelatinase activity was decreased in lungs from torpid animals, indicating inhibition of the Zn(2+)-dependent MMP-2 and MMP-9. Moreover, expression of CBS and tissue levels of H(2)S were increased in torpor. All changes normalized during arousal. Inhibition of gelatinase activity in torpor is likely caused by quenching of Zn(2+) by the sulphide ion of H(2)S. In accord, inhibition of CBS normalized gelatinase activity in torpid animals. Conversely, NaHS decreased the gelatinase activity of euthermic animals, which was attenuated by excess Zn(2+). Similar results were obtained on the activity of the Zn(2+)-dependent angiotensin converting enzyme. Our data indicate that increased production of H(2)S through CBS in hamster lungs during torpor contributes to remodeling by inhibition of gelatinase activity and possibly by suppression of the inflammatory response. Although administration of H(2)S is known to induce metabolic suppression in non-hibernating mammals ('suspended animation'), this is the first report implying endogenous H(2)S production in natural hibernation.

Gelatinase Expression in Retinoblastoma: Modulation of LHBETATAGRetinal Tumor Development by Anecortave Acetate

Gelatinases, matrix metalloproteinase (MMP)-2, and MMP-9 are known for their importance in angiogenesis and tumor biology. The purpose of this study was to test the hypothesis that anecortave acetate (AA) decreases transgenic retinoblastoma (RB) tumor burden by modulating gelatinase activity. To assess the possible gelatinase modulation after AA treatment, a single subconjunctival injection of AA (300 microg) was delivered to the right eyes of 10-week-old LH(BETA)T(AG) mice. Eyes were evaluated for gelatinase expression and activity by gel and in situ zymography at 24 hours, 48 hours, and 1 week after treatment. Gel zymography of whole eye extracts and in situ zymography of retinal tumors showed strong gelatinase expression and activity within transgenic RB tumors. AA treatment in RB transgenic mice resulted in a significant decrease of gelatinase activity 1 week after AA treatment. Surprisingly, there was an initial transient upregulation of MMP-9 activity in whole eye extracts at 24 and 48 hours after AA treatment in both LH(BETA)T(AG) transgenic and wild-type mice. This increase was not observed in the tumors. As suggested by our data, inhibition of gelatinase activity appears to be a mechanism of action of AA. AA treatment results in a decrease in gelatinase activity that correlates with the significant decrease in tumor burden shown by the authors' previous studies. However, the significance of the initial, transient upregulation of gelatinase by AA injection is unknown, and further studies are warranted. Combining antiangiogenic agents with multiple mechanisms of action has the potential to enhance RB tumor control.

Upregulation of matrix metalloproteinase-9 and tissue inhibitors of metalloproteinases in rapid atrial pacing-induced atrial fibrillation

Remodeling of atrial extracellular matrix (ECM) in atrial fibrillation (AF) involves changes in the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs). The contributions of MMPs and TIMPs to the pathogenesis of AF development have not been clearly defined. This study evaluated the in situ activity and expression of gelatinases (MMP-2 and MMP-9) and their relationship with TIMP-1 or TIMP-3 in atria undergoing rapid atrial pacing for the induction of AF (4 weeks' pacing followed by 2 weeks of maintained AF) in pigs. In AF atria, in situ gelatinase activity was mainly localized in the interstitium of atrial myocardium, and was significantly larger than that of sinus rhythm control (i.e., sham control). The significant increase of MMP-9 in its pro-form and mRNA level, but not MMP-2, was shown to be responsible for the increased gelatinase activity in atria with AF. The inhibitory activities of glycosylated TIMP-1 and TIMP-3, but not TIMP-2, in AF tissues were markedly elevated and also localized in the atrial interstitium. TIMP-1 was found to be mostly colocalized with gelatinase activity over the AF tissues, implying the coexistence of gelatinase activity and TIMP-1, but TIMP-3 appeared only partially colocalized and discontinued the gelatinase activity surrounding the cardiomyocytes. TIMP-1 and TIMP-3 may play differential roles in the inhibition of gelatinase activity in vivo. Together with the survey of several MMPs transcripts and the level of transforming growth factor-β1 (TGF-β1), we proposed that the increased activity of gelatinase (i.e., MMP-9), TIMP-1 and TIMP-3 and their interaction may contribute to atrial ECM remodeling of AF.

Circulating level of gelatinase activity predicts ventricular remodeling in patients with acute myocardial infarction

Background Matrix metalloproteinase (MMP) plays an important role in the development of ventricular remodeling in an animal model of acute myocardial infarction (AMI). We examined whether circulating MMP activity can predict left ventricular (LV) remodeling after AMI in humans. Methods We measured the circulating level of MMP-2 and MMP-9 activities (gelatinase activity) at 14 days after the onset of AMI by gelatin zymography in 52 consecutive patients (age 62±2). All patients underwent direct PTCA and stenting at an acute stage, and were treated subsequently with losartan or enalapril. Biplane left ventriculography was performed at admission, and 2 weeks and 6 months after the onset of AMI. Results We expressed gelatinolysis activity as the ratio to MMP-2 standard. Mean gelatinase activity was 0.721±0.013. We divided patients into two groups, groups with gelatinolysis activity <0.72 (low group, n=27) and >0.72 (high group, n=25). Either change in LV end-diastolic volume index (LVEDVI, ml/m 2) or end-systolic volume index (LVESVI, ml/m 2) from admission to 2 weeks was not different between the two groups. Changes in both LVEDVI and LVESVI from 2 weeks to 6 months were greater in high gelatinolysis activity group than those in low activity group. Moreover, circulating level of gelatinolysis activity was positively correlated with changes in LVEDVI and LVESVI from 2 weeks to 6 months. Conclusion These results demonstrate that circulating level of gelatinase activity can predict LV remodeling after AMI. Inhibition of gelatinase activity at the acute phase may be a therapeutic strategy for the prevention of remodeling after AMI.

Inhibition of breast cancer cell extracellular matrix degradative activity by chemically modified tetracyclines

BACKGROUND. Inhibition of tumour cell proliferation, invasion and metastasis by chemically modified tetracyclines has been ascribed to inhibition of matrix metalloproteinase (MMP) activity.METHODS. Exposure of the human breast carcinoma cell line MDA‐MB‐231 or its MMP‐9‐overproducing transfected clone (E‐10) to 6‐demethyl, 6‐deoxy, 4‐de [dimethylamino]‐tetracycline (CMT‐3), a chemically modified non‐antimicrobial tetracycline followed by analysis using gelatinase activity assay, zymography, degradation of radiolabelled extracellular matrix (ECM), Western blotting, TNF‐α ELISA and cell viability assays.RESULTS. CMT‐3 treatment results in diminution in extracellular MMP‐9 protein levels as well as inhibition of gelatinase activity. This prevents cell‐mediated ECM degradation without inducing general cytostasis or cytotoxicity. Culturing E‐10 cells in 10 or 20 µM CMT‐3 diminished secreted MMP‐9 levels by 45% or 60%, respectively, but did not affect levels of most other secreted proteins, including tissue inhibitor of Metalloproteinases (TIMP‐1). ECM degradation by E‐10 cells or their conditioned medium was inhibited by ∼ 20%–30% in the presence of 20 µM CMT‐3, reflecting inhibition of MMP‐9 activity in addition to diminution of released MMP‐9 levels. TNF‐α levels were also diminished in E‐10 conditioned medium in the presence of CMT‐3, but cell viability, measured by MTS reduction and cytosolic LDH retention, was unaffected.CONCLUSIONS. It is proposed that the reduction in ECM‐degradative activity reflects diminished levels of expression as well as inhibition of enzymatic activity of MMPs released by cells in the presence of CMT‐3. These multiple effects of CMT‐3 may offer promise for use in suppressing tumour invasion, and if used in conjunction with other chemotherapy agents, may lead to more successful treatment of cancer.

Inhibition of gelatinase activity in human airway epithelial cells and fibroblasts by dexamethasone and beclomethasone.

The effects of dexamethasone and beclomethasone on gelatinase activity released from lung epithelial cells (A549, NCI-H292 and Calu-3 cell lines and NHBE primary cultures) and human lung fibroblasts (HLF) were investigated. All cells spontaneously released gelatin-degrading activity but the amounts were unaffected by treatment with glucocorticoids. Phorbol myristate acetate (PMA) increased the amount of gelatinase activity in conditioned media prepared from all cell types examined. In epithelial cells, PMA induced the expression of gelatinase B, whereas in HLF the increased gelatinase activity resulted from increased activation of gelatinase A. Dexamethasone and beclomethasone produced concentration-dependent inhibition of PMA-induced gelatinase activity in HLF and epithelial cell lines. In the epithelial cell lines, the inhibition of activity was associated with an attenuation of enzyme induction by PMA. In contrast, primary cultures of human bronchial epithelial cells were unresponsive to dexamethasone at concentrations that were maximally effective at inhibiting gelatinase activity induced in other cells.

Expression and activity of metalloprotease-2 in tumoral and non-tumoral areas of livers with metastasis: [formula omitted] Unité de Recherches Hépatologiques, INSERM U-49, ∗Laboratoire d'Anatomie Pathologique B, +Clinique Chirurgicale B, Faculté de Médecine, CHRU Pontchaillou, 35033 RENNES, France

Remodeling of atrial extracellular matrix (ECM) in atrial fibrillation (AF) involves changes in the expression of matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs). The contributions of MMPs and TIMPs to the pathogenesis of AF development have not been clearly defined. This study evaluated the in situ activity and expression of gelatinases (MMP-2 and MMP-9) and their relationship with TIMP-1 or TIMP-3 in atria undergoing rapid atrial pacing for the induction of AF (4 weeks' pacing followed by 2 weeks of maintained AF) in pigs. In AF atria, in situ gelatinase activity was mainly localized in the interstitium of atrial myocardium, and was significantly larger than that of sinus rhythm control (i.e., sham control). The significant increase of MMP-9 in its pro-form and mRNA level, but not MMP-2, was shown to be responsible for the increased gelatinase activity in atria with AF. The inhibitory activities of glycosylated TIMP-1 and TIMP-3, but not TIMP-2, in AF tissues were markedly elevated and also localized in the atrial interstitium. TIMP-1 was found to be mostly colocalized with gelatinase activity over the AF tissues, implying the coexistence of gelatinase activity and TIMP-1, but TIMP-3 appeared only partially colocalized and discontinued the gelatinase activity surrounding the cardiomyocytes. TIMP-1 and TIMP-3 may play differential roles in the inhibition of gelatinase activity in vivo. Together with the survey of several MMPs transcripts and the level of transforming growth factor-β1 (TGF-β1), we proposed that the increased activity of gelatinase (i.e., MMP-9), TIMP-1 and TIMP-3 and their interaction may contribute to atrial ECM remodeling of AF.