Association between elevated serum matrix metalloproteinase-2 and tumor necrosis factor-α, and clinical symptoms in male patients with treatment-resistant and chronic medicated schizophrenia

BACKGROUND

Inflammation has an important role in the pathogenesis of schizophrenia. The aim of this study was to investigate the levels of tumor necrosis factor (TNF) and matrix metalloproteinase-2 (MMP-2) in male patients with treatment-resistant schizophrenia (TRS) and chronic medicated schizophrenia (CMS), and the relationship with psychopathology.

METHODS

The study enrolled 31 TRS and 49 cm male patients, and 53 healthy controls. Serum MMP-2 and TNF-α levels were measured by the Luminex liquid suspension chip detection method. Positive and Negative Syndrome Scale (PANSS) scores were used to evaluate symptom severity and Repeatable Battery for the Assessment of Neuropsychological Status was used to assess cognitive function.

RESULTS

Serum TNF-α and MMP-2 levels differed significantly between TRS, CMS and healthy control patients (F = 4.289, P = 0.016; F = 4.682, P = 0.011, respectively). Bonferroni correction demonstrated that serum TNF-α levels were significantly elevated in CMS patients (P = 0.022) and MMP-2 levels were significantly higher in TRS patients (P = 0.014) compared to healthy controls. In TRS patients, TNF-α was negatively correlated with age (r=-0.435, P = 0.015) and age of onset (r=-0.409, P = 0.022). In CMS patients, MMP-2 and TNF-α were negatively correlated with PANSS negative and total scores, and TNF-α was negatively correlated with PANSS general psychopathology scores (all P < 0.05). MMP-2 levels were positively correlated with TNF-α levels (P < 0.05), but not with cognitive function (P > 0.05).

CONCLUSION

The results indicate the involvement of inflammation in the etiology of TRS and CMS. Further studies are warranted.

In Silico Analysis of Cissus rotundifolia Constituents as Human Neutrophil Elastase (HNE), Matrix Metalloproteinases (MMP 2 and MMP 9), and Tyrosinase Inhibitors

Cissus rotundifolia has been reported to possess various biological activities such as anti-diabetic, anti-fertility, anti-hyperlipidemic, anti-malarial, anti-osteoporotic, and anti-parasitic activities. Therefore in the present study, eleven selected constituents of Cissus rotundifolia which includes aconitic acid, astragalin, acteoside, aliospiroside A, beta amyrin, bergenin, formononetin, gallic acid, isovitexin, isoorientin, and isoquercitrin were studied on the docking behavior of human neutrophil elastase (HNE), matrix metalloproteinases (MMP 2 and MMP 9), and tyrosinase by using PatchDock method. Furthermore, molecular physicochemical, bioactivity score/drug-likeness, ADME (absorption, distribution, metabolism, and excretion), and toxicity analyses were also carried out using Molinspiration, Swiss ADME, and ProTox-II methods, respectively. The molecular physicochemical investigation showed that three ligands such as acteoside, aliospiroside A, and isoorientin have three violations for Lipinski's rule of five. Similarly, ADME analysis one ligand (formononetin) predicated to have high blood-brain barrier (BBB) permeability effect. The docking studies showed that isovitexin exhibited the highest atomic contact energy (-341.61 kcal/mol) for human neutrophil elastase (HNE), more over alliospiroside A has shown maximum atomic contact energy for both matrix metalloproteinases (MMP 2 [-618.00 kcal/mol] and MMP 9 [-634.73 kcal/mol]). Furthermore, isoquercitrin has exhibited the highest atomic contact energy (-145.70 kcal/mol) for tyrosinase. Thus, the present investigation outcome provides new knowledge in understanding eleven Cissus rotundifolia constituents as possible novel inhibitors against HNE, MMP 2, MMP 9, and tyrosinase.

Insight into the structural requirement of aryl sulphonamide based gelatinases (MMP-2 and MMP-9) inhibitors - Part I: 2D-QSAR, 3D-QSAR topomer CoMFA and Naïve Bayes studies - First report of 3D-QSAR Topomer CoMFA analysis for MMP-9 inhibitors and jointly inhibitors of gelatinases together

Gelatinases [gelatinase A - matrix metalloproteinase-2 (MMP-2), gelatinase B - matrix metalloproteinase-9 (MMP-9)] play key roles in many disease conditions including cancer. Despite some research work on gelatinases inhibitors both jointly and individually had been reported, challenges still exist in achieving potency as well as selectivity. Here in part I of a series of work, we have reported the structural requirement of some arylsulfonamides. In particular, regression-based 2D-QSARs, topomer CoMFA (comparative molecular field analysis) and Bayesian classification models were constructed to refine structural features for attaining better gelatinase inhibitory activity. The 2D-QSAR models exhibited good statistical significance. The descriptors nsssN, SHBint6, SHBint7, PubchemFP629 were directly correlated with the MMP-2 binding affinities whereas nsssN, SHBint10 and AATS2i were directly proportional to MMP-9 binding affinities. The topomer CoMFA results indicated that the steric and electrostatic fields play key roles in gelatinase inhibition. The established Naïve Bayes prediction models were evaluated by fivefold cross validation and an external test set. Furthermore, important molecular descriptors related to MMP-2 and MMP-9 binding affinities and some active/inactive fragments were identified. Thus, these observations may be helpful for further work of aryl sulphonamide based gelatinase inhibitors in future.

Celastrol inhibit the proliferation, invasion and migration of human cervical HeLa cancer cells through down-regulation of MMP-2 and MMP-9

The present study evaluated the anticancer potential of celastrol through down-regulation of matrix metalloproteinase-2 (MMP-2) and MMP-9. HeLa cells were incubated with different concentrations of celastrol (1, 10 and 100 µM) for 48h. Doxorubicin was used as a reference drug. Cancer cell migration, apoptosis, cell viability and mitochondrial fragmentation were evaluated following celastrol treatment. In addition, the expression level of MMP-2, MMP-9 and caspase-3 was evaluated following celastrol treatment. HeLa cell viability was 94.1 ± 7, 53.4 ± 4 and 36.3 ± 2% at 1-100 µM of celastrol, respectively. Apoptotic cell numbers were increased, and inhibition of larger wounds in cancer cells was observed following celastrol treatment. Celastrol-treated cells showed condensed nuclei and clumped mitochondria. Reduced expression of MMP-2 and MMP-9 and increased expression of caspase-3 were observed following celastrol treatment. Based on the experimental results, we are concluding that the celastrol was effective against HeLa cervical cancer cells.

Investigation of Alpinia calcarata constituent interactions with molecular targets of rheumatoid arthritis: docking, molecular dynamics, and network approach

Rheumatoid arthritis (RA) is a systemic autoimmune disorder that commonly affects multiple joints of the body. Currently, there is no permanent cure to the disease, but it can be managed with several potent drugs that cause serious side effects on prolonged use. Traditional remedies are considered promising for the treatment of several diseases, particularly chronic conditions, because they have lower side effects compared to synthetic drugs. In folklore, the rhizome of Alpinia calcarata Roscoe (Zingiberaceae) is used as a major ingredient of herbal formulations to treat RA. Phytoconstituents reported in A. calcarata rhizomes are diterpenoids, sesquiterpenoid, flavonoids, phytosterol, and volatile oils. The present study is intended to understand the molecular-level interaction of phytoconstituents present in A. calcarata rhizomes with RA molecular targets using computational approaches. A total of 30 phytoconstituents reported from the plant were used to carry out docking with 36 known targets of RA. Based on the docking results, 4 flavonoids were found to be strongly interacting with the RA targets. Further, molecular dynamics simulation confirmed stable interaction of quercetin with 6 targets (JAK3, SYK, MMP2, TLR8, IRAK1, and JAK1), galangin with 2 targets (IRAK1 and JAK1), and kaempferol (IRAK1) with one target of RA. Moreover, the presence of these three flavonoids was confirmed in the A. calcarata rhizome extract using LC-MS analysis. The computational study suggests that flavonoids present in A. calcarata rhizome may be responsible for RA modulatory activity. Particularly, quercetin and galangin could be potential development candidates for the treatment of RA. Investigation of Alpinia calcarata constituent interactions with molecular targets of rheumatoid arthritis: docking, molecular dynamics, and network approach.

Functional expression and purification of the untagged C-terminal domain of MMP-2 from Escherichia coli inclusion bodies

The C-terminal domain (CTD) of MMP-2, which includes a hemopexin-like domain, has been increasingly studied as an alternative target in developing selective intervention strategies towards MMP-2. Moreover, The CTD itself has been implicated in a growing number of biological events, either MMP-dependent or -independent. The production of CTD, however, has been mostly based on the uncontrolled lysis of the latent ProMMP-2 or fusion protein expression that leaves a fusion tag. In this work we present a facile production of the untagged CTD in E. coli. The target protein was expressed as inclusion bodies, and we established an efficient wash and refolding strategy that allows us to obtain the target protein in extremely high purity. The yield was established at ~6 mg/L of the culture medium, which would greatly facilitate the production and hence the biological study of CTD. The method described herein might also prove useful for related (domain) proteins in MMP family and beyond.

Matrix metalloproteinase-2-targeted superparamagnetic Fe3O4-PEG-G5-MMP2@Ce6 nanoprobes for dual-mode imaging and photodynamic therapy

This work explored the application of matrix metalloproteinase 2-targeted superparamagnetic nanoprobes for magnetic resonance imaging (MRI), near infrared (NIR) fluorescence imaging and photodynamic therapy of tumors. PEG, PAMAM (G5) and matrix metalloproteinase 2 (MMP2) were attached to the surface of carboxylated Fe3O4 nanoparticles (NPs) using a chemical coupling method and then finally loaded with the photosensitizer chlorin e6 (Ce6). In vitro and in vivo experiments demonstrated that the Fe3O4-PEG-G5-MMP2@Ce6 nanoprobes exhibited excellent stability, precise tumor targeting and biocompatibility. Furthermore, the fluorescence properties of Fe3O4-PEG-G5-MMP2@Ce6 nanoprobes were analogous to Ce6 and could be employed for fluorescence imaging. Meanwhile, the Fe3O4-PEG-G5-MMP2@Ce6 nanoprobes have also been shown to be effective as contrast agents for T2-weighted MRI. The target molecule MMP2 enhanced the tumor targeting ability of Fe3O4-PEG-G5-MMP2@Ce6 nanoprobes. Additionally, the Fe3O4-PEG-G5-MMP2@Ce6 nanoprobes significantly inhibited tumor growth compared with PBS and free Ce6. This work will inspire greater enthusiasm for the construction of multifunctional magnetic nanoplatforms for biomedical applications.

Tumor Imaging Using Radiolabeled Matrix Metalloproteinase-Activated Anthrax Proteins

Increased activity of matrix metalloproteinases (MMPs) is associated with worse prognosis in different cancer types. The wild-type protective antigen (PA-WT) of the binary anthrax lethal toxin was modified to form a pore in cell membranes only when cleaved by MMPs (to form PA-L1). Anthrax lethal factor (LF) is then able to translocate through these pores. Here, we used a 111In-radiolabeled form of LF with the PA/LF system for noninvasive in vivo imaging of MMP activity in tumor tissue by SPECT. Methods: MMP-mediated activation of PA-L1 was correlated to anthrax receptor expression and MMP activity in a panel of cancer cells (HT1080, MDA-MB-231, B8484, and MCF7). Uptake of 111In-radiolabeled PA-L1, 111In-PA-WTK563C, or 111In-LFE687A (a catalytically inactive LF mutant) in tumor and normal tissues was measured using SPECT/CT imaging in vivo. Results: Activation of PA-L1 in vitro correlated with anthrax receptor expression and MMP activity (HT1080 > MDA-MB-231 > B8484 > MCF7). PA-L1-mediated delivery of 111In-LFE687A was demonstrated and was corroborated using confocal microscopy with fluorescently labeled LFE687A Uptake was blocked by the broad-spectrum MMP inhibitor GM6001. In vivo imaging showed selective accumulation of 111In-PA-L1 in MDA-MB-231 tumor xenografts (5.7 ± 0.9 percentage injected dose [%ID]/g) at 3 h after intravenous administration. 111In-LFE687A was selectively delivered to MMP-positive MDA-MB-231 tumor tissue by MMP-activatable PA-L1 (5.98 ± 0.62 %ID/g) but not by furin-cleavable PA-WT (1.05 ± 0.21 %ID/g) or a noncleavable PA variant control, PA-U7 (2.74 ± 0.24 %ID/g). Conclusion: Taken together, our results indicate that radiolabeled forms of mutated anthrax lethal toxin hold promise for noninvasive imaging of MMP activity in tumor tissue.

Atheroma Niche-Responsive Nanocarriers for Immunotherapeutic Delivery

Nanomedicine is a promising, noninvasive approach to reduce atherosclerotic plaque burden. However, drug delivery is limited without the ability of nanocarriers to sense and respond to the diseased microenvironment. In this study, nanomaterials are developed from peptide amphiphiles (PAs) that respond to the increased levels of matrix metalloproteinases 2 and 9 (MMP2/9) or reactive oxygen species (ROS) found within the atherosclerotic niche. A pro-resolving therapeutic, Ac2-26, derived from annexin-A1 protein, is tethered to PAs using peptide linkages that cleave in response to MMP2/9 or ROS. By adjusting the molar ratios and processing conditions, the Ac2-26 PA can be co-assembled with a PA containing an apolipoprotein A1-mimetic peptide to create a targeted, therapeutic nanofiber (ApoA1-Ac226 PA). The ApoA1-Ac2-26 PAs demonstrate release of Ac2-26 within 24 h after treatment with MMP2 or ROS. The niche-responsive ApoA1-Ac2-26 PAs are cytocompatible and reduce macrophage activation from interferon gamma and lipopolysaccharide treatment, evidenced by decreased nitric oxide production. Interestingly, the linkage chemistry of ApoA1-Ac2-26 PAs significantly affects macrophage uptake and retention. Taken together, these findings demonstrate the potential of PAs to serve as an atheroma niche-responsive nanocarrier system to modulate the inflammatory microenvironment, with implications for atherosclerosis treatment.

Functional characterization of a matrix metalloproteinase 2 gene in Litopenaeus vannamei

Matrix metalloproteinases (MMPs) contribute to both normal and pathological tissue remodeling. They act as regulatory molecules by working in enzyme cascades as well as processing matrix proteins, cytokines, growth factors and adhesion molecules to generate fragments with biological effects. So MMPs could play distrinct roles in the process of pathogen infection. In present study, we cloned a MMP-2 (LvMMP-2) gene from Litopenaeus vannamei. LvMMP-2, highly expressed in epidermis, located to endoplasmic reticulum in S2 cells. Results of real-time RT-PCR assay showed that LvMMP-2 was induced in shrimp hemocytes upon unfolded protein response or oxidative stress, but not via heat shock treatment. It is proved that the promoter activity of LvMMP-2 was enhanced by NF-E2-related factor 2 and AP-1 factor c-Jun. Further research showed that down-regulated LvMMP-2 contributing to oxidative stress injury, could reduce the cumulative mortality of shrimps under oxidative stress. Besides, our study also indicated that LvMMP-2 was accelerated by lipopolysaccharides injection. LvMMP-2 in S2 could increase the promoter activity of several antimicrobial peptide genes, and knocked-down expression of LvMMP-2 depressed the expression of penaeidin2 and β-Defensin. Moreover, we showed that down-regulated LvMMP-2 suppressed the cumulative mortality of shrimp infected with white spot syndrome virus (WSSV) or with Vibrio alginolyticus. Collecting results suggested that LvMMP-2 involves in shrimp innate immune response, and also contributes to tissue injury caused by WSSV infection.

Endotoxin-induced changes of type VII collagen- cleaving matrix metalloproteinases in lamellar tissue of extracorporeally perfused equine limbs

OBJECTIVE To investigate the effect of lipopolysaccharide (LPS) on type VII collagen- cleaving matrix metalloproteinases (MMPs) in the lamellar tissue of extracorporeally perfused equine limbs. SAMPLE 10 right forelimbs and 3 left forelimbs collected from 10 adult horses after slaughter at a licensed abattoir. PROCEDURES Extracorporeal perfusion of the isolated equine limbs was performed for 10 hours under physiologic conditions (control-perfused limbs; n = 5) and with the addition of 80 ng of LPS/L of perfusate (LPS-perfused limbs; 5). Lamellar tissue specimens were then collected from the dorsal aspect of the hooves. Additionally, corresponding control specimens were collected from the 3 nonperfused left forelimbs. Immunohistochemical analysis was performed on paraffin-embedded tissue blocks with antibodies against total (latent and active) MMP-1, MMP-2, MMP-8, and MMP-9 as well as antibody against active MMP-9. Intensity of immunohistochemical staining was scored, and stain distribution in the lamellar tissue was noted. RESULTS Staining intensity of total and active MMP-9 was significantly increased in LPS-perfused versus control-perfused limbs. No such difference was identified for MMP-1, MMP-2, and MMP-8. CONCLUSIONS AND CLINICAL RELEVANCE Of the 4 MMPs that are capable of degrading type VII collagen, MMP-9 was the only one for which production increased in the lamellar tissue of isolated equine limbs perfused with versus without a clinically relevant concentration of LPS. These results suggested that MMP-9 may be involved in initiation of pathological changes in lamellar tissue in endotoxin-induced laminitis, whereas MMP-1, MMP-2, and MMP-8 may be less relevant.

Effects of Oncostatin M on Invasion of Primary Trophoblasts under Normoxia and Hypoxia Conditions

PURPOSE

To investigate the effect of oncostatin M (OSM) on protein expression levels and enzymatic activities of matrix metalloprotainase (MMP)-2 and MMP-9 in primary trophoblasts and the invasiveness thereof under normoxia and hypoxia conditions.

MATERIALS AND METHODS

Protein expression levels and enzymatic activities of MMP-2 and MMP-9 in primary trophoblasts under normoxia and hypoxia conditions were examined by Western blot and zymography, respectively. Effects of exogenous OSM on the in vitro invasion activity of trophoblasts according to oxygen concentration were also determined. Signal transducer and activator of transcription 3 (STAT3) siRNA was used to determine whether STAT3 activation in primary trophoblasts was involved in the effect of OSM.

RESULTS

OSM enhanced protein expression levels and enzymatic activities of MMP-2 and MMP-9 in term trophoblasts under hypoxia condition, compared to normoxia control (p<0.05). OSM-induced MMP-2 and MMP-9 enzymatic activities were significantly suppressed by STAT3 siRNA silencing under normoxia and hypoxia conditions (p<0.05). Hypoxia alone or OSM alone did not significantly increase the invasiveness of term trophoblasts. However, the invasion activity of term trophoblasts was significantly increased by OSM under hypoxia, compared to that without OSM treatment under normoxia.

CONCLUSION

OSM might be involved in the invasiveness of extravillous trophoblasts under hypoxia conditions via increasing MMP-2 and MMP-9 enzymatic activities through STAT3 signaling. Increased MMP-9 activity by OSM seems to be more important in primary trophoblasts.

Long Non-Coding RNA XLOC_008466 Functions as an Oncogene in Human Non-Small Cell Lung Cancer by Targeting miR-874

BACKGROUND

The therapy and prognosis of lung cancer are difficult because of multiple genetic and epigenetic alterations. Long non-coding RNAs (lncRNAs) have been verified as new mediators of cancer development and progression by virtue of their various functions. Here, we focused on the lncRNA XLOC_008466 based on previous microarray data. However, whether aberrant expression of XLOC_008466 in human non-small cell lung cancer (NSCLC) is correlated with malignancy, metastasis or prognosis has not been elucidated.

METHODS

We performed real-time PCR, CCK-8, flow cytometry, trans-well, western blotting, luciferase reporter assays, RNA immunoprecipitation (RIP) assay and surface plasmon resonance (SPR) assay to detect the function of XLOC_008466 in NSCLC.

RESULTS

Up-regulation of XLOC_008466 in NSCLC patients was related to lymph node metastasis and the TNM stage. In vitro, down-regulation of XLOC_008466 inhibited cell proliferation and invasion of A549 and H460 cells in vitro, but promoted cell apoptosis. Experiments on mechanisms revealed that XLOC_008466 functioned as a ceRNA, directly binding to miR-874, and could affect cell proliferation, apoptosis and invasion through regulation of miR-874 expression as well as by increasing matrix metalloproteinase 2 (MMP2) and X-linked inhibitor of apoptosis (XIAP) expression.

CONCLUSIONS

XLOC_008466 functions as an oncogene in NSCLC by regulating the miR-874-MMP2/XIAP axis, which indicates that XLOC_008466 may be a useful marker and potential therapeutic target in NSCLC.

Distance-dependent magnetic resonance tuning as a versatile MRI sensing platform for biological targets

Nanoscale distance-dependent phenomena, such as Förster resonance energy transfer, are important interactions for use in sensing and imaging, but their versatility for bioimaging can be limited by undesirable photon interactions with the surrounding biological matrix, especially in in vivo systems. Here, we report a new type of magnetism-based nanoscale distance-dependent phenomenon that can quantitatively and reversibly sense and image intra-/intermolecular interactions of biologically important targets. We introduce distance-dependent magnetic resonance tuning (MRET), which occurs between a paramagnetic 'enhancer' and a superparamagnetic 'quencher', where the T₁ magnetic resonance imaging (MRI) signal is tuned ON or OFF depending on the separation distance between the quencher and the enhancer. With MRET, we demonstrate the principle of an MRI-based ruler for nanometre-scale distance measurement and the successful detection of both molecular interactions (for example, cleavage, binding, folding and unfolding) and biological targets in in vitro and in vivo systems. MRET can serve as a novel sensing principle to augment the exploration of a wide range of biological systems.

A new synthetic matrix metalloproteinase inhibitor reduces human mesenchymal stem cell adipogenesis

Development of adipose tissue requires the differentiation of less specialized cells, such as human mesenchymal stem cells (hMSCs), into adipocytes. Since matrix metalloproteinases (MMPs) play critical roles in the cell differentiation process, we conducted investigations to determine if a novel mercaptosulfonamide-based MMP inhibitor (MMPI), YHJ-7-52, could affect hMSC adipogenic differentiation and lipid accumulation. Enzyme inhibition assays, adipogenic differentiation experiments, and quantitative PCR methods were employed to characterize this inhibitor and determine its effect upon adipogenesis. YHJ-7-52 reduced lipid accumulation in differentiated cells by comparable amounts as a potent hydroxamate MMPI, GM6001. However, YHJ-7-82, a non-inhibitory structural analog of YHJ-7-52, in which the zinc-binding thiol group is replaced by a hydroxyl group, had no effect on adipogenesis. The two MMPIs (YHJ-7-52 and GM6001) were also as effective in reducing lipid accumulation in differentiated cells as T0070907, an antagonist of peroxisome-proliferator activated receptor gamma (PPAR-gamma), at a similar concentration. PPAR-gamma is a typical adipogenic marker and a key regulatory protein for the transition of preadiopocyte to adipocyte. Moreover, MMP inhibition was able to suppress lipid accumulation in cells co-treated with Troglitazone, a PPAR-gamma agonist. Our results indicate that MMP inhibitors may be used as molecular tools for adipogenesis and obesity treatment research.

Inhibition of Matrix Metalloproteinase 9 Enhances Rod Survival in the S334ter-line3 Retinitis Pigmentosa Model

Retinitis Pigmentosa (RP) is one of the most common forms of inherited visual loss with the initial degeneration of rod photoreceptors, followed by a progressive cone photoreceptor deterioration. Coinciding with this visual loss, the extracellular matrix (ECM) is reorganized, which alters matrix metalloproteinase (MMP) activity levels. A potential pathological role of MMPs, MMP-9 in particular, involves an excitotoxicity-mediated physiological response. In the current study, we examine the MMP-9 and MMP-2 expression levels in the rhodopsin S334ter-line3 RP rat model and investigate the impact of treatment with SB-3CT, a specific MMP-9 and MMP-2 inhibitor, on rod cell survival was tested. Retinal MMP-9 and MMP-2 expression levels were quantified by immunoblot analysis from S334ter-line3 rats compared to controls. Gelatinolytic activities of MMP-9 and MMP-2 by zymography were examined. The geometry of rod death was further evaluated using Voronoi analysis. Our results revealed that MMP-9 was elevated while MMP-2 was relatively unchanged when S334ter-line 3 retinas were compared to controls. With SB-3CT treatment, we observed gelatinolytic activity of both MMPs was decreased and diminished clustering associated with rod death, in addition to a robust preservation of rod photoreceptors. These results demonstrate that up-regulation of MMP-9 in retinas of S334ter-line3 are associated with rod death. The application of SB-3CT dramatically interferes with mechanisms leading to apoptosis in an MMP-9-dependent manner. Future studies will determine the feasibility of using SB-3CT as a potential therapeutic strategy to slow progression of vision loss in genetic inherited forms of human RP.

Seeking for Non-Zinc-Binding MMP-2 Inhibitors: Synthesis, Biological Evaluation and Molecular Modelling Studies

Matrix metalloproteinases (MMPs) are an important family of zinc-containing enzymes with a central role in many physiological and pathological processes. Although several MMP inhibitors have been synthesized over the years, none reached the market because of off-target effects, due to the presence of a zinc binding group in the inhibitor structure. To overcome this problem non-zinc-binding inhibitors (NZIs) have been recently designed. In a previous article, a virtual screening campaign identified some hydroxynaphtyridine and hydroxyquinoline as MMP-2 non-zinc-binding inhibitors. In the present work, simplified analogues of previously-identified hits have been synthesized and tested in enzyme inhibition assays. Docking and molecular dynamics studies were carried out to rationalize the activity data.

Increased Nanoparticle Delivery to Brain Tumors by Autocatalytic Priming for Improved Treatment and Imaging

The blood-brain barrier (BBB) is partially disrupted in brain tumors. Despite the gaps in the BBB, there is an inadequate amount of pharmacological agents delivered into the brain. Thus, the low delivery efficiency renders many of these agents ineffective in treating brain cancer. In this report, we proposed an "autocatalytic" approach for increasing the transport of nanoparticles into the brain. In this strategy, a small number of nanoparticles enter into the brain via transcytosis or through the BBB gaps. After penetrating the BBB, the nanoparticles release BBB modulators, which enables more nanoparticles to be transported, creating a positive feedback loop for increased delivery. Specifically, we demonstrated that these autocatalytic brain tumor-targeting poly(amine-co-ester) terpolymer nanoparticles (ABTT NPs) can readily cross the BBB and preferentially accumulate in brain tumors at a concentration of 4.3- and 94.0-fold greater than that in the liver and in brain regions without tumors, respectively. We further demonstrated that ABTT NPs were capable of mediating brain cancer gene therapy and chemotherapy. Our results suggest ABTT NPs can prime the brain to increase the systemic delivery of therapeutics for treating brain malignancies.

An MMP-2 Responsive Liposome Integrating Antifibrosis and Chemotherapeutic Drugs for Enhanced Drug Perfusion and Efficacy in Pancreatic Cancer

Fibrotic stroma, a critical character of pancreatic tumor microenvironment, provides a critical barrier against the penetration and efficacy of various antitumor drugs. Therefore, new strategies are urgently needed to alleviate the fibrotic mass and increase the drug perfusion within pancreatic cancer tissue. In our current work, we developed a β-cyclodextrin (β-CD) modified matrix metalloproteinase-2 (MMP-2) responsive liposome, integrating antifibrosis and chemotherapeutic drugs for regulation of pancreatic stellate cells (PSCs), a key source of the fibrosis, and targeted delivery of cytotoxic drugs for pancreatic cancer therapy. These liposomes disassembed into two functional parts upon MMP-2 cleavage at the tumor site. One part was constituted by the β-CDs and the antifibrosis drug pirfenidone, which was kept in the stroma and inhibited the expression of collagen I and TGF-β in PSCs, down-regulating the fibrosis and decreasing the stromal barrier. The other segment, the RGD peptide-modified-liposome loading the chemotherapeutic drug gemcitabine, targeted and killed pancreatic tumor cells. This integrated nanomedicine, showing an increased drug perfusion without any overt side effects, may provide a potential strategy for improvement of the pancreatic cancer therapy.

MMP2-Targeting and Redox-Responsive PEGylated Chlorin e6 Nanoparticles for Cancer Near-Infrared Imaging and Photodynamic Therapy

A unique matrix metalloproteinase 2-targeted photosensitizer delivery platform was developed in this study for tumor-targeting imaging and photodynamic therapy. The model photosensitizer therapeutic agent chlorin e6 (Ce6) was first covalently conjugated with matrix metalloproteinase 2-cleavable polypeptide and then modified with polyethylene glycol via a redox-responsive cleavable disulfide linker. The resultant matrix metalloproteinase 2-cleavable polypeptide modified PEGylated Ce6 (PEG-SS-Ce6-MMP2) nanoparticles, which formed via self-assembly, were observed to be monodisperse and significantly stable in aqueous solution. In addition, owing to their cellular redox-responsiveness at the cleavable disulfide linker, the PEG-SS-Ce6-MMP2 nanoparticles were able to release Ce6 rapidly. Despite displaying enhanced intracellular internalization, the synthesized PEG-SS-Ce6-MMP2 nanoparticles did not compromise their phototoxic effects toward A549 cancer cells when compared with free Ce6 and PEGylated Ce6 nanoparticles. In vivo experiments further revealed that, in contrast with the free Ce6 or with the PEGylated Ce6 nanoparticles, the PEG-SS-Ce6-MMP2 nanoparticles showed a remarkable increase in tumor-targeting ability and a significantly improved photodynamic therapeutic efficiency in A549 tumor-bearing mice. These results suggest that the PEG-SS-Ce6-MMP2 nanoparticles hold great potential for tumor-targeting imaging and photodynamic therapy.

Activin A Increases Human Trophoblast Invasion by Inducing SNAIL-Mediated MMP2 Up-Regulation Through ALK4

CONTEXT

Activin A increases matrix metalloproteinase (MMP) 2 expression and cell invasion in human trophoblasts, but whether the expression of MMP2 is essential for the proinvasive effect of activin A has yet to be determined. Moreover, the identity of the activin receptor-like kinase (ALK; TGF-β type I receptors) and downstream transcription factors (eg, SNAIL and SLUG) mediating the effects of activin on MMP2 expression and trophoblast cell invasion remains unknown.

OBJECTIVE

To elucidate the role of MMP2 in activin A-induced human trophoblast cell invasion as well as the involvement of ALK4 and SNAIL.

DESIGN

HTR8/SVneo immortalized human extravillous cytotrophoblast (EVT) cells and primary cultures of human first-trimester EVT cells were used as study models. Small interfering RNA (siRNA)-mediated knockdown approaches were used to investigate the molecular determinants of activin A-mediated functions.

MAIN OUTCOME MEASURES

Levels of mRNA and protein were examined by reverse transcription-quantitative real-time PCR and Western blot, respectively. Cell invasiveness was measured by Matrigel-coated transwell assays.

RESULTS

Treatment of HTR8/SVneo cells with activin A increased the production of SNAIL, SLUG, and MMP2 without altering that of MMP9, TIMP1, TIMP2, TWIST, RUNX2, ZEB1, or ZEB2. Similarly, activin A up-regulated the mRNA and protein levels of SNAIL and MMP2 in primary EVT cells. Knockdown of SNAIL attenuated activin A-induced MMP2 up-regulation in HTR8/SVneo and primary EVT cells. In HTR8/SVneo cells, activin A-induced production of SNAIL and MMP2 was abolished by pretreatment with the TGF-β type I receptor (ALK4/5/7) inhibitor SB431542 or siRNA targeting ALK4, SMAD2/3, or common SMAD4. Likewise, knockdown of ALK4 or SMAD4 abolished the stimulatory effects of activin A on SNAIL and MMP2 expression in primary EVT cells. Importantly, activin A-induced HTR8/SVneo and primary EVT cell invasion were attenuated by siRNA-mediated depletion of ALK4 or MMP2.

CONCLUSION

Activin A induces human trophoblast cell invasion by inducing SNAIL-mediated MMP2 expression through ALK4 in a SMAD2/3-SMAD4-dependent manner.

Site-specific Effects of DUOX1-Related Peroxidase on Intercellular Apoptosis Signaling

Intercellular apoptosis-inducing HOCl signaling is known as an interplay between superoxide anions/H₂O₂ of transformed target cells and dual oxidase 1 (DUOX1)-related peroxidase that is released from neighboring non-transformed or transformed effector cells. Effector cells are dispensable when the release of the peroxidase domain of DUOX1 from target cells is prevented through inhibition of matrix metalloproteinase (MMP) activity. Membrane-associated peroxidase is then co-localized to NADPH oxidase 1 (NOX1) and establishes HOCl signaling specifically in transformed cells, using the same biochemical pathways as classical intercellular HOCl signaling. Membrane-associated peroxidase protects against exogenous HOCl through reversal of the peroxidase reaction. In addition, membrane-associated peroxidase protects against NO/peroxynitrite signaling as it oxidates NO and decomposes peroxynitrite. The protective function of membrane-associated peroxidase (in the absence of MMP) is analogous to that of catalase, whereas the destructive effect of the enzyme, i.e. the synthesis of HOCl, is independent of its localization and of MMP activity.

Enzyme responsive mesoporous silica nanoparticles for targeted tumor therapy in vitro and in vivo

This study reports a biocompatible controlled drug release system based on mesoporous silica nanoparticles (MSNs) for tumor microenvironment responsive drug delivery. It was fabricated by grafting phenylboronic acid conjugated human serum albumin (PBA-HSA) onto the surfaces of MSNs as a sealing agent, via an intermediate linker of a functional polypeptide, which was composed of two functional units: the polycation cell penetrating peptide (CPP) polyarginine, and matrix metalloproteinase 2 (MMP-2) substrate peptide. A series of characterizations confirmed that the system had been successfully constructed. In vitro tests proved that the anticancer drug loading system could efficiently induce cell apoptosis in vitro. More importantly, the in vivo tumor experiments confirmed that the anticancer loading system could efficiently inhibit tumor growth with minimal side effects.

The role of collagen charge clusters in the modulation of matrix metalloproteinase activity

Members of the matrix metalloproteinase (MMP) family selectively cleave collagens in vivo. Several substrate structural features that direct MMP collagenolysis have been identified. The present study evaluated the role of charged residue clusters in the regulation of MMP collagenolysis. A series of 10 triple-helical peptide (THP) substrates were constructed in which either Lys-Gly-Asp or Gly-Asp-Lys motifs replaced Gly-Pro-Hyp (where Hyp is 4-hydroxy-L-proline) repeats. The stabilities of THPs containing the two different motifs were analyzed, and kinetic parameters for substrate hydrolysis by six MMPs were determined. A general trend for virtually all enzymes was that, as Gly-Asp-Lys motifs were moved from the extreme N and C termini to the interior next to the cleavage site sequence, kcat/Km values increased. Additionally, all Gly-Asp-Lys THPs were as good or better substrates than the parent THP in which Gly-Asp-Lys was not present. In turn, the Lys-Gly-Asp THPs were also always better substrates than the parent THP, but the magnitude of the difference was considerably less compared with the Gly-Asp-Lys series. Of the MMPs tested, MMP-2 and MMP-9 most greatly favored the presence of charged residues with preference for the Gly-Asp-Lys series. Lys-Gly-(Asp/Glu) motifs are more commonly found near potential MMP cleavage sites than Gly-(Asp/Glu)-Lys motifs. As Lys-Gly-Asp is not as favored by MMPs as Gly-Asp-Lys, the Lys-Gly-Asp motif appears advantageous over the Gly-Asp-Lys motif by preventing unwanted MMP hydrolysis. More specifically, the lack of Gly-Asp-Lys clusters may diminish potential MMP-2 and MMP-9 collagenolytic activity. The present study indicates that MMPs have interactions spanning the P23-P23' subsites of collagenous substrates.

Metformin rescues the MG63 osteoblasts against the effect of high glucose on proliferation

AIMS. To study the proliferation of osteoblasts and genes expression under normal glucose, high glucose, and metformin (Met). METHODS. MG63 osteoblast-like cells were cultured in osteogenic medium supplemented with normal glucose (glucose 5.5 mmol/L) or high glucose (glucose 16.7 mmol/L) and metformin + high glucose (Met 300  μmol/L + glucose 16.7 mmol/L). Proliferation was detected with CCK-8 assay at days 1, 3, and 7. Real-time PCR and Western blot were performed to compare the expression of collagen I (Col I), osteocalcin (OCN), osteoprotegerin (OPG), receptor activator for NF- κB ligand (RANKL), and metal matrix proteinases 1 and 2 (MMP1, MMP2). Alkaline phosphatase (ALP) activity was also detected at days 6, 12, and 18. RESULTS. Exposure to high glucose inhibited the proliferation of osteoblasts (P < 0.05), with suppressed OCN and OPG. Meanwhile, Col I, RANKL, MMP1, and MMP2 were unaffected. Metformin attenuated the suppression on proliferation with increased expression of Col I, OCN, and OPG, meanwhile suppressing MMP1 and MMP2. High glucose lowered the intracellular ALP, while metformin raised it. Metformin attenuated the downregulation of ALP completely at day 6, partly at day 12, but not at day 18. CONCLUSIONS. Metformin attenuated the suppression effect of high glucose to the osteoblast proliferation and gene expression, more prominently in earlier stage.

Hyperglycaemia promotes cerebral barrier dysfunction through activation of protein kinase C-β

AIM

To examine whether protein kinase C (PKC) and associated downstream mechanisms are involved in hyperglycaemia (HG)-evoked blood-brain barrier (BBB) damage.

METHODS

The activities of total PKC (Peptag assay), NADPH oxidase (lucigenin assay) and matrix metalloproteinase-2 (MMP-2; gelatin zymography) were measured in human brain microvascular endothelial cells (HBMEC) exposed to normoglycaemia (5.5 mM) or HG (25 mM) using the specific assays indicated in parentheses. The integrity and function of the in vitro models of human BBB were assessed by measurements of transendothelial electrical resistance and paracellular flux of permeability markers, respectively. Occludin protein expression was studied by immunoblotting.

RESULTS

HG significantly compromised the BBB integrity and enhanced total PKC activity to which increases in PKC-β and PKC-βII isoforms contributed the most. Elevations in NADPH oxidase and MMP-2 activities and decreases in occludin levels contributed to barrier dysfunction. Selective inhibition of PKC-β isoform prevented the changes observed in occludin expression and the aforementioned enzyme activities and thus effectively preserved barrier integrity. Similarly, apocynin, a specific NADPH oxidase inhibitor, also effectively neutralized the effects of HG on barrier integrity, MMP-2 activity, occludin expression and PKC-β activity.

CONCLUSION

HG promotes cerebral-barrier dysfunction through activation of PKC-β and consequent stimulations of oxidative stress and tight junction dissolution.

A superabsorbent polymer-containing wound dressing efficiently sequesters MMPs and inhibits collagenase activity in vitro

Superabsorbent polymer (SAP)-containing wound dressings present a valuable and unique category of wound management products. An in vitro approach was used to assess the effects of a new SAP dressing in treatment of non-healing wounds. It was shown that the SAP dressing possesses a significant binding capacity for MMP-2 and MMP-9 in vitro (P\0.001). The inclusion of the bound proteases was so strong that no MMP-2 and only marginal amounts of MMP-9 were released from the dressing samples in a subsequent elution step. In addition, the SAP dressing was able to take up collagenase and reduce its activity in vitro. However, collagenase was not completely inactivated upon binding and enzyme-mediated substrate turnover could be observed at the dressings. In conclusion, in vitro data confirm the positive effect of the SAP wound dressing observed in vivo. The findings suggest that it should be specifically useful for highly exuding wounds with an elevated proteolytic activity that needs to be reduced to support healing.

Matrix metalloproteinase-2 (MMP-2) generates soluble HLA-G1 by cell surface proteolytic shedding

Human leukocyte antigen-G (HLA-G) molecules are non-classical HLA class I antigens with an important role in pregnancy immune regulation and inflammation control. Soluble HLA-G proteins can be generated through two mechanisms: alternative splicing and proteolytic release, which is known to be metalloprotease mediated. Among this class of enzymes, matrix metalloproteinases (MMPs) might be involved in the HLA-G1 membrane cleavage. Of particular interest are MMP-2 and MMP-9, which regulate the inflammatory process by cytokine and chemokine modulation. We evaluated the effect of MMP-9 and MMP-2 on HLA-G1 membrane shedding. In particular, we analyzed the in vitro effect of these two gelatinases on the secretion of HLA-G1 via proteolytic cleavage in 221-G1-transfected cell line, in JEG3 cell line, and in peripheral blood mononuclear cells. The results obtained by both cell lines showed the role of MMP-2 in HLA-G1 shedding. On the contrary, MMP-9 was not involved in this process. In addition, we identified three possible highly specific cleavage sites for MMP-2, whereas none were detected for MMP-9. This study suggests an effective link between MMP-2 and HLA-G1 shedding, increasing our knowledge on the regulatory machinery beyond HLA-G regulation in physiological and pathological conditions.

Inhibitory effects of dried longan (Euphoria longana Lam.) seed extract on invasion and matrix metalloproteinases of colon cancer cells

The critical step in colorectal cancer progression and associated mortality is cancer invasion, which depends on two key gelatinase enzymes, matrix metalloproteinases-2 and -9. Dried longan ( Euphoria longana Lam.) seed is a rich natural source of antioxidant polyphenols.This study evaluated the effect of dried longan seeds on colon cancer cell invasion via gelatinase function and expression. Three dried longan seed fractions were collected by Sephadex LH-20 column chromatography. They showed a potent inhibitor on colorectal cancer cell invasion and gelatinase activity. The antigelatinase activities of fractions 1 and 2 were a direct effect via Zn²⁺ chelation, whereas fraction 3 modulated indirectly through suppression of zymogen activators. Among the fractions, only fraction 3 reduced the gelatinase expression, which was correlated with the levels of tissue inhibitor of metalloproteinase-1 and may as well involve the p38 mitogen-activated protein kinases and the c-Jun N-terminal kinase signaling pathways. This primary research has manifested and encouraged the anticancer properties of dried longan seed extracts with potential inhibitory effects on cancer cell invasion as well as antigelatinase activity and expression in colon cancer cells.

Generation of induced pluripotent stem cells with CytoTune, a non-integrating Sendai virus

One of the major obstacles in generating induced pluripotent stem cells for research or downstream applications is the potential modifications of cellular genome as a result of using integrating viruses during reprogramming. Another major disadvantage of reprogramming cells with integrating vectors is that silencing and activation of transgenes are unpredictable, which may affect terminal differentiation potential and increase the risk of using iPSC-derived cells. Here we describe a protocol for the generation of induced pluripotent stem cells using a non-integrating RNA virus, Sendai virus, to efficiently generate transgene-free iPSCs starting with different cell types as well as in feeder-free conditions.

Matrix metalloproteinase 2 of grass carp Ctenopharyngodon idella (CiMMP2) is involved in the immune response against bacterial infection

The gene encoding matrix metalloproteinase 2 (MMP2) was cloned from grass carp (Ctenopharyngodon idella), and its expression levels during Aeromonas hydrophila infection and embryonic development stages were evaluated. The complete open reading frame of CiMMP2 was 1974 bp in length, encoding a 658-amino acid polypeptide. The deduced MMP2 protein contained four conserved domain structures, including an N-terminal signal sequence, a propeptide domain, three repeats of fibronectin-type II domain inserted in the catalytic domain and a C-terminal hemopexin-like domain. Phylogenetic analysis of MMP2s grouped grass carp with other teleosts. Detected in all fish tissues examined, CiMMP2 expression increased in the spleen and head kidney at 4 h and was significantly downregulated at 1 d after A. hydrophila infection. CiMMP2 transcripts were present in unfertilized eggs, suggesting its maternal origin. These findings implicate an important role for CiMMP2 in A. hydrophila-related diseases and early embryonic developmental stages of grass carp.

Anti-fibrotic cardio protective efficacy of aminoguanidine against streptozotocin induced cardiac fibrosis and high glucose induced collagen up regulation in cardiac fibroblasts

This study mainly focuses on cardio protective anti-fibrotic activity of aminoguanidine against streptozotocin induced cardiac fibrosis and high glucose induced collagen accumulation in cardiac fibroblasts. Dysregulation of matrix metalloproteinase especially 2 and 9 were considered to be responsible for the abnormal collagen deposition, which resulting improper cardiac contractile function in diabetic mice. Mice received a single dose of streptozotocin (100 mg/kg) through tail vein to induce diabetes. Normal and diabetic mice received aminoguanidine orally (100 mg/kg/day) throughout the study period of 8 weeks. Cardiac fibroblasts cultured and exposed to high glucose, aminoguanidine and both for 48 h. Collagen quantitatively estimated in both in vivo and in vitro models. Altered structural changes were studied using the Masson tri-chrome staining, TEM images of cardiac sections. Increased collagen and metalloproteinase activities were confirmed using gelatin zymography, western blotting and gene expression studies. The exact mechanism responsible for high glucose induced collagen up regulation in diabetic heart was incompletely understood. From this above in vivo and in vitro results, we conclude that, the cardio protective anti fibrotic activity of amino guanidine was mainly attributed by exhibiting the inhibitory efficacy against streptozotocin and high glucose induced collagen accumulation probably by inhibiting high glucose altered metalloproteinase-2 and -9 activities.

A novel intracellular isoform of matrix metalloproteinase-2 induced by oxidative stress activates innate immunity

BACKGROUND

Experimental and clinical evidence has pinpointed a critical role for matrix metalloproteinase-2 (MMP-2) in ischemic ventricular remodeling and systolic heart failure. Prior studies have demonstrated that transgenic expression of the full-length, 68 kDa, secreted form of MMP-2 induces severe systolic failure. These mice also had unexpected and severe mitochondrial structural abnormalities and dysfunction. We hypothesized that an additional intracellular isoform of MMP-2, which affects mitochondrial function is induced under conditions of systolic failure-associated oxidative stress.

METHODOLOGY AND PRINCIPAL FINDINGS

Western blots of cardiac mitochondria from the full length MMP-2 transgenics, ageing mice and a model of accelerated atherogenesis revealed a smaller 65 kDa MMP-2 isoform. Cultured cardiomyoblasts subjected to transient oxidative stress generated the 65 kDa MMP-2 isoform. The 65 kDa MMP-2 isoform was also induced by hypoxic culture of cardiomyoblasts. Genomic database analysis of the MMP-2 gene mapped transcriptional start sites and RNA transcripts induced by hypoxia or epigenetic modifiers within the first intron of the MMP-2 gene. Translation of these transcripts yields a 65 kDa N-terminal truncated isoform beginning at M(77), thereby deleting the signal sequence and inhibitory prodomain. Cellular trafficking studies demonstrated that the 65 kDa MMP-2 isoform is not secreted and is present in cytosolic and mitochondrial fractions, while the full length 68 kDa isoform was found only in the extracellular space. Expression of the 65 kDa MMP-2 isoform induced mitochondrial-nuclear stress signaling with activation of the pro-inflammatory NF-κB, NFAT and IRF transcriptional pathways. By microarray, the 65 kDa MMP-2 induces an innate immunity transcriptome, including viral stress response genes, innate immunity transcription factor IRF7, chemokines and pro-apoptosis genes.

CONCLUSION

A novel N-terminal truncated intracellular isoform of MMP-2 is induced by oxidative stress. This isoform initiates a primary innate immune response that may contribute to progressive cardiac dysfunction in the setting of ischemia and systolic failure.

Effects of ethanolic extract from Radix Scrophulariae on ventricular remodeling in rats

PURPOSE

To explore the effects of ethanolic extract of Radix Scrophulariae (EERS) on ventricular remodeling in rats.

METHODS

Rats with coronary artery ligation (CAL) were randomly assigned to 5 groups: CAL model; CAL plus 40 mg/kg captopril; CAL plus 60 mg/kg, 120 mg/kg, 240 mg/kg EERS. Sham operation rats were randomly assigned to 2 groups, sham-operated control and sham-operated plus 120 mg/kg EERS. The rats were orally administered with the corresponding drugs or drinking water for 14 weeks. The left ventricular weight index (LVWI) and heart weight index (HWI) were determined. Myocardium tissue was stained with hematoxylin and eosin or picric acid/Sirius red for cardiomyocyte cross-section area or collagen content measurements respectively. The concentrations of hydroxyproline (Hyp), matrix metalloproteinase 2 (MMP-2), angiotensin II (Ang II), aldosterone (ALD), endothelin 1 (ET-1), atrial natriuretic peptide (ANP), tumor necrosis factor α (TNF-α) and renin activity (RA) in myocardium or serum were determined. Real-time RT-PCR was used to detect the mRNA expressions of angiotensin converting enzyme (ACE), ET-1 and ANP.

RESULTS

EERS could significantly reduce the LVWI and HWI, decrease heart tissue concentrations of Hyp and collagen deposition, diminish cardiomyocyte cross-section area, reduce the tissue level of Ang II, ET-1, ANP and TNF-α. EERS could also down regulate the mRNA expression of ACE, ET-1 and ANP in myocardium.

CONCLUSION

EERS attenuates ventricular remodeling. The mechanisms may be related to restraining the excessive activation of RAAS, TNF-α and modulating some gene expressions associated with cardiac hypertrophy.

Insights into the complex formed by matrix metalloproteinase-2 and alloxan inhibitors: molecular dynamics simulations and free energy calculations

Matrix metalloproteinases (MMP) are well-known biological targets implicated in tumour progression, homeostatic regulation, innate immunity, impaired delivery of pro-apoptotic ligands, and the release and cleavage of cell-surface receptors. Hence, the development of potent and selective inhibitors targeting these enzymes continues to be eagerly sought. In this paper, a number of alloxan-based compounds, initially conceived to bias other therapeutically relevant enzymes, were rationally modified and successfully repurposed to inhibit MMP-2 (also named gelatinase A) in the nanomolar range. Importantly, the alloxan core makes its debut as zinc binding group since it ensures a stable tetrahedral coordination of the catalytic zinc ion in concert with the three histidines of the HExxHxxGxxH metzincin signature motif, further stabilized by a hydrogen bond with the glutamate residue belonging to the same motif. The molecular decoration of the alloxan core with a biphenyl privileged structure allowed to sample the deep S₁′ specificity pocket of MMP-2 and to relate the high affinity towards this enzyme with the chance of forming a hydrogen bond network with the backbone of Leu116 and Asn147 and the side chains of Tyr144, Thr145 and Arg149 at the bottom of the pocket. The effect of even slight structural changes in determining the interaction at the S₁′ subsite of MMP-2 as well as the nature and strength of the binding is elucidated via molecular dynamics simulations and free energy calculations. Among the herein presented compounds, the highest affinity (pIC₅₀ = 7.06) is found for BAM, a compound exhibiting also selectivity (>20) towards MMP-2, as compared to MMP-9, the other member of the gelatinases.

Impact of respiratory pattern on lung mechanics and interstitial proteoglycans in spontaneously breathing anaesthetized healthy rats

AIM

The aim of this study was to investigate the effect of different pattern of spontaneous breathing on the respiratory mechanics and on the integrity of the pulmonary extracellular matrix.

METHODS

Experiments were performed on adult healthy rats in which different spontaneously breathing pattern was elicited through administration of two commonly used anaesthetic mixtures: pentobarbital/urethane (P/U) and ketamine/medetomidine (K/M). The animals (five per group) were randomized and left to spontaneously breath for 10 min (P/U-sham; K/M-sham) or for 4h (P/U-4h; K/M-4h), targeting the anaesthesia level to obtain a tidal volume of about 8 mL kg(-1) body wt. At the end of the experiment, lung matrix integrity was assessed through determination of the glycosaminoglycans (GAGs) content in the lung parenchyma.

RESULTS

Compared with K/M, anaesthesia with P/U cocktail induced: (1) a higher respiratory rate and minute ventilation attained with lower P(a) CO(2) ; (2) a higher pressure-time-product and work of breathing per minute; (3) a lower static lung compliance; (4) an increased activation of lung tissue metalloproteases; and (5) greater extraction of pulmonary interstitial GAGs.

CONCLUSIONS

This study suggests that the breathing pattern induced by the different anaesthetic regimen may damage the pulmonary interstitium even during spontaneous breathing at physiological tidal volumes.

Controlling and switching the morphology of micellar nanoparticles with enzymes

Micelles were prepared from polymer-peptide block copolymer amphiphiles containing substrates for protein kinase A, protein phosphatase-1, and matrix metalloproteinases 2 and 9. We examine reversible switching of the morphology of these micelles through a phosphorylation-dephosphorylation cycle and study peptide-sequence directed changes in morphology in response to proteolysis. Furthermore, the exceptional uniformity of these polymer-peptide particles makes them amenable to cryo-TEM reconstruction techniques lending insight into their internal structure.

SKOV-3 cell imaging by paramagnetic particles labeled with hairpin cell-penetrating peptides

BACKGROUND

The hairpin cell-penetrating peptides (hCPPs) demonstrate an interesting characteristic of conditioned activation by molecules. We hypothesized that hCPPs have the potential to selectively deliver a paramagnetic gadolinium probe into the matrix metalloproteinase 2 (MMP-2) positive human ovary adenocarcinoma cell lines, SKOV-3.

METHODS

hCPPs were synthesized and labeled with 1,4,7,10-tetraazacyclododecane-N,N',N'',N''' tetraacetic acid gadolinium (III) (Gd-DOTA) and fluorescein isothiocyanate (FITC) by f-moc strategy using a standard solid phase peptide synthesis protocol. MMP-2 expression and activity were demonstrated by reverse transcriptase polymerase chain reaction (RT-PCR) and zymography. Internalization and location of hCPPs in SKOV-3 cells were observed by fluorescein imaging and flow cytometery. Selective delivery of Gd-DOTA in SKOV-3 cells was observed by magnetic resonance imaging (MRI) and transmission electron microscopy (TEM).

RESULTS

The uptake of hCPPs by SKOV-3 cells depended on the activity of MMP-2. T1WI signals of SKOV-3 cells treated with Gd-DOTA-hCPPs suggested the uptake of Gd-DOTA-hCPPs increased in a time- (r = 0.990, P < 0.01) and concentration-dependent manner (r = 0.964, P < 0.001), but was inhibited by a MMP-2 inhibitor. Electron-dense particles observed in the cytoplasm and nucleus by transmission electron microscopy proved the intracellular penetration of gadolinium.

CONCLUSIONS

hCPPs can be used as an effective vector for an MRI molecular probe to assess the activity of MMP-2.

[The design and enzymatic hydrolysis of activatable cell-penetrating peptide]

The paper is aimed to study the enzymatic hydrolysis of the activatable cell-penetrating peptide (ACPP) that was designed and synthesized. The ACPP was composed of three parts, polyanionic sequence peptide, peptide sequence that specifically cleaved by matrix metalloproteinase (MMP) and cell penetrating peptide (CPP). The ACPP was hydrolyzed by type IV collagenase (MMP-2/9) under the condition of 37 degrees C and was monitored by reversed-phase high performance liquid chromatography (RP-HPLC). The efflux of peak was collected and detected by matrix assisted laser desorption ionization orthogonal time of flight mass spectrometry (MALDIO-TOF-MS) to speculate the sequences of the peptide fragments. The results indicated that the ACPP could be cleaved by type IV collagenase at target site as predicted, released CPP. The half life of the cleavage was about 4 h. Meanwhile, the peptide fragments may be cleaved again at other sites by type IV collagenase.

pH dependence of the enzymatic processing of collagen I by MMP-1 (fibroblast collagenase), MMP-2 (gelatinase A), and MMP-14 ectodomain

The proteolytic processing of collagen I by three matrix metalloproteinases (MMPs), a collagenase (MMP-1), a gelatinase (MMP-2), and the ectodomain of a membrane-type metalloproteinase (MMP-14), has been investigated at 37 °C between pH 6.0 and 9.2, a pH range reflecting conditions found in different body compartments under various physiopathological processes. In the proteolytic degradation the native collagen triple helix must be partially unwound to allow the binding of α chains to the protease's active-site cleft. We have found that MMP-1 interacts with the two types of collagen I α chains in a similar fashion, whereas both MMP-2 and MMP-14 bind the two α chains in a different way. The overall enzymatic activity is higher on the α-2 chain for both MMP-1 and MMP-2, whereas the MMP-14 ectodomain preferentially cleaves the α-1 chain. In MMP-2 a marked difference for substrate affinity (higher for the α-1 chain) is overwhelmed by an even more marked propensity to cleave the α-2 chain. As a whole, the three classes of MMPs investigated appear to process collagen I in a significantly different fashion, so various MMPs play different roles in the collagen homeostasis in various compartments (such as bloodstream, synovial fluid, normal and tumoral tissues), where different pH values are observed.

Co-purified gelatinases alter the stability and biological activities of human plasma fibronectin preparations

BACKGROUND AND OBJECTIVE

Fibronectin (FN) is an important cell adhesion molecule that is used widely to characterize cell behavior. Preparations of FN purified from human plasma by gelatin-Sepharose affinity chromatography typically also contain gelatin-binding gelatinases that may cleave FN, reduce its stability and alter its biological activities. Available methods for separating gelatinases from FN are resource demanding. Therefore, our objective was to devise a time- and cost-efficient protocol for purification of gelatinase-free FN.

MATERIAL AND METHODS

Experiments tested the elution profiles for FN and gelatinases from gelatin-Sepharose using a concentration range (1-7%) of dimethyl sulfoxide (DMSO) and 4 m urea as eluants. Subsequently, we explored the sequential application of those eluants for differential elution of gelatinases and FN using a single affinity column. Finally, experiments characterized the stability of purified FN with or without contaminating gelatinases, as well as the effects of FN degradation on cell attachment and migration.

RESULTS

Assay optimization demonstrated that pre-elution with 3% DMSO efficiently eliminated gelatinases but not FN from gelatin-Sepharose, whereas subsequent elution with 4 m urea released FN. Sequential elutions with DMSO and urea produced gelatinase-free FN, which was more stable than FN eluted by urea only. Fibronectin degradation did not affect human gingival fibroblast attachment, but increased cell migration significantly.

CONCLUSION

The present experiments devised a time- and cost-efficient protocol for eliminating gelatinases during purification of human plasma FN. Gelatinase-free FN preparations had greater stability, which may be essential for experiments because FN fragments have altered biological activities compared with intact FN.

Bioluminescent nanosensors for protease detection based upon gold nanoparticle-luciferase conjugates

This communication reports the use of click chemistry to site-specifically conjugate bioluminescent Renilla luciferase proteins to gold nanoparticles (Au NPs) for sensing protease activity. The bioluminescent emission from luciferase was efficiently quenched by Au NPs, but significantly recovered after the proteolytic cleavage.

Dose responses to inhalation of endotoxin, hay dust suspension and Aspergillus fumigatus extract in horses as measured by levels and activation of matrix metalloproteinase-9

REASONS FOR PERFORMING STUDY

Airway matrix metalloproteinases (MMPs) increase after endotoxin (LPS) exposure, but there are no reports describing dose-dependent increases or activation following exposure.

OBJECTIVES

To study matrix metalloproteinase-9 (MMP-9) and -2 (MMP-2) responses in bronchoalveolar lavage fluid (BALF) from heaves-susceptible and control horses following inhalation of hay dust suspension (HDS), LPS and Aspergillus fumigatus extract (AFE).

METHODS

Heaves-susceptible (n = 7) and control (n = 6) horses received inhalation challenges with 3 different doses of HDS and LPS. Heaves-susceptible horses (n = 6) also received 3 different doses of AFE and one dose of AFE depleted of endotoxin (AFE-LPS). BALF collected following inhalation challenges was analysed using gelatin zymography. Gelatinolytic bands were identified as complex, pro-MMP-9, active MMP-9, pro-MMP-2 and active MMP-2 based on molecular weights.

RESULTS

Each challenge substance induced a dose-dependent elevation in gelatinolytic activity. The dose-dependency was most evident for pro-MMP-9 and total MMP-9 levels in heaves-susceptible horses following LPS challenges.

CONCLUSIONS

There is a dose-dependent elevation in MMP-9 in BALF of heaves-susceptible and control horses following inhalation challenge with organic dust and some of its components, elevation being more marked in heaves-susceptible horses. Organic dust components vary in their pro-inflammatory potential.

POTENTIAL RELEVANCE

This study supports the role of MMPs in the pathogenesis of heaves and highlights the potential value of protease inhibitors in attenuating the airway inflammatory response to inhaled organic dust.

Equine laminitis: increased transcription of matrix metalloproteinase-2 (MMP-2) occurs during the developmental phase

REASONS FOR PERFORMING STUDY

The dysadhesion and destruction of lamellar basement membrane of laminitis may be due to increased lamellar metalloproteinase activity. Characterising lamellar metalloproteinase-2 (MMP-2) and locating it in lamellar tissues may help determine if laminitis pathology is associated with increased MMP-2 transcription.

OBJECTIVES

To clone and sequence the cDNA encoding lamellar MMP-2, develop antibody and in situ hybridisation probes to locate lamellar MMP-2 and quantitate MMP-2 transcription in normal and laminitis tissue.

METHODS

Total RNA was isolated, fragmented by RT-PCR, cloned into vector and sequenced. Rabbit anti-equine MMP-2 and labelled MMP-2 riboprobe were developed to analyse and quantitate MMP-2 expression.

RESULTS

Western immunoblotting with anti-MMP-2 detected 72 kDa MMP-2 in hoof tissue homogenates and cross-reacted with human MMP-2. Immunohistochemistry and in situ hybridisation detected MMP-2 in the cytoplasm of basal and parabasal cells in close proximity to the lamellar basement membrane. Northern analysis and quantitative real-time PCR showed MMP-2 expression significantly (P < 0.01) elevated in laminitis affected tissues.

CONCLUSION

The lamellar pathology of laminitis is associated with increased transcription of MMP-2.

POTENTIAL RELEVANCE

Real-time PCR analysis of lamellar MMP-2 accurately monitors laminitis development at the molecular level and can be used diagnostically and for testing preventive strategies. Controlling increased MMP-2 transcription may ameliorate or prevent laminitis in high risk clinical situations. Our findings represent a warning to clinicians that the basement membrane lesion of laminitis is insidious and well under way before clinical signs are apparent.

DFT studies of the ring-opening mechanism of SB-3CT, a potent inhibitor of matrix metalloproteinase 2

SB-3CT is a 2-[(arylsulfonyl)methyl]thiirane that achieves potent inhibition, by a thiirane-opening mechanism, of the MMP2 and MMP9 zinc metalloproteases. The deprotonation mechanism for thiirane opening of SB-3CT and for the opening of its oxirane analogue, both relevant to the inhibition of MMP2, was investigated computationally using the acetate anion as the Brønsted base and in methanol and acetonitrile as solvents. The activation barriers for the reaction show a significant stereoelectronic effect. The lowest energy paths have the breaking C-H bond gauche to both sulfone oxygens and with this C-H bond anti to the breaking C-S bond of the thiirane. The calculated primary isotope effect agrees with experimental data.

Self-assembling peptide amphiphile-based nanofiber gel for bioresponsive cisplatin delivery

The aim of this study is to develop a bioresponsive cisplatin (CDDP) delivery system with a self-assembling peptide amphiphile (PA) comprising a cell-adhesive matrix metalloproteinase-2 (MMP-2)-sensitive GTAGLIGQRGDS and a fatty acid. A biomimetic CDDP-PA gel was spontaneously formed upon incubating a mixture of CDDP and the PA for 5 h at 37 degrees C. CDDP-PA gel formation was confirmed by rheological analysis. The structure of self-assembled CDDP-PA nanofibers inside the gel was determined by transmission electron microscopy (TEM). Bioresponsive drug release from the biomimetic gel was demonstrated by in vitro MMP-2-triggered CDDP release. The MMP-2-sensitive CDDP release was dependent on the enzyme concentration in the medium. Enzymatic degradation of the CDDP-PA gel was confirmed by TEM images of the gel degraded in an MMP-2 containing medium. The MMP-2-triggered CDDP release as well as the presentation of RGDS in the gel would potentially provide a spatially and temporally controlled delivery system for targeted anticancer drug delivery.

Matrix metalloproteinase-2 and -9 activities in human keloids, hypertrophic and atrophic scars: a pilot study

Proteolytic degradation of extracellular matrix is one of the principal features of cutaneous wound healing but little is known about the activities of gelatinases; matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) on abnormal scar formation. The aim of this study is to determine collagen levels and the gelatinase activities in tissue from hypertrophic scars, atrophic scars, keloids and donor skin in 36 patients and 14 donors. Gelatinase levels (proenzyme + active enzyme) were determined by ELISA and their activities by gelatin zymography. MMP-9 activity was undetectable in gelatin zymography analysis. Pro-MMP-2 levels (median) were highest in normal skin group 53.58 (36.40-75.11) OD microg(-1) protein, while active MMP-2 levels were highest in keloid group 52.53 (42.47-61.51) OD microg(-1) protein. The active/pro ratio was the highest in keloid group 0.97 followed by hypertrophic scar, normal skin and atrophic scar groups 0.69 > 0.54 > 0.48, respectively. According to results of our study, the two-phase theory of the duration of hypertrophic scar and keloid formation can be supported by the data of tissue collagen and gelatinase analysis. This study is the first to relate scar formation relationship in regard to gelatinase activation ratio in a keloid, hypertrophic and atrophic scar patient group which is chosen appropriate in age and sex.

The cloning and expression of matrix metalloproteinase-2 and tissue inhibitor of matrix metalloproteinase 2 in normal canine lymph nodes and in canine lymphoma

Matrix metalloproteinase-2 (MMP-2) and its inhibitor, tissue inhibitor of matrix metalloproteinase 2 (TIMP2), are known to be important in cancer. The purposes of this study were to determine the cDNA sequence of canine MMP-2 and to investigate the expression patterns of MMP-2 and TIMP2 in normal canine lymph nodes and spontaneously arising canine lymphomas. We cloned and sequenced a PCR product containing most (1901 base pairs) of the coding sequence of canine MMP-2 that translates into a 623 amino acid protein. The cDNA and deduced amino acid sequences are highly homologous to those of other mammalian species. Canine MMP-2 and TIMP2 mRNAs were detectable in the majority of normal lymph node and lymphomatous samples evaluated. No statistical difference was identified when comparing the expression of either gene with regard to normal versus neoplastic nodes, nodal versus extranodal lymphoma, lymphoma grade, or B versus T cell immunophenotype.

Apolactoferrin inhibits the catalytic domain of matrix metalloproteinase-2 by zinc chelation

Lactoferrin (LTF) is a multifunctional iron-binding protein that is also capable of binding other divalent metal cations, especially Zn2+. Recent investigations indicate that lactoferrin levels are elevated in many disease conditions in which matrix metalloproteinases (MMPs), particularly MMP-2, are also elevated, suggesting that the 2 proteins may interact. This possibility was examined by determining the effect of LTF in its holo (metal-bound) and apo (metal-free) forms on the proteolytic activity of MMP-2 and other similar zinc metalloproteases. Pre-incubation with apolactoferrin, but not hololactoferrin, greatly reduced the hydrolysis of a peptide substrate by MMP-2, but not by MMP-1, -8, -9, or -13. This inhibition was specific for the 42 kDa catalytic domain fragment of MMP-2 lacking the hemopexin domain, since the 66 kDa form was poorly inhibited by apolactoferrin. The inhibition of the MMP-2 catalytic domain was strongly temperature sensitive, indicating that the conformation of one or both proteins is crucial to this interaction. To ascertain the mechanism of inhibition, increasing concentrations of ZnCl2 and FeCl2 were added to the reaction. While addition of Fe2+ did not reverse inhibition, the addition of Zn2+ resulted in a recovery of MMP-2 activity, and furthermore, zinc-saturated LTF did not inhibit MMP-2. Together, these data strongly suggest that apolactoferrin is capable of removing the catalytic zinc from the active site of MMP-2, although an exosite-based interaction between the 2 proteins cannot be fully ruled out. This inhibitory activity suggests a novel function for LTF and may represent a novel regulatory mechanism that regulates proteolysis by MMP-2 in vivo.