Bioinformatic characterization of angiotensin-converting enzyme 2, the entry receptor for SARS-CoV-2

The World Health Organization declared the COVID-19 epidemic a public health emergency of international concern on March 11th, 2020, and the pandemic is rapidly spreading worldwide. COVID-19 is caused by a novel coronavirus SARS-CoV-2, which enters human target cells via angiotensin converting enzyme 2 (ACE2). We used a number of bioinformatics tools to computationally characterize ACE2 by determining its cell-specific expression in trachea, lung, and small intestine, derive its putative functions, and predict transcriptional regulation. The small intestine expressed higher levels of ACE2 mRNA than any other organ. By immunohistochemistry, duodenum, kidney and testis showed strong signals, whereas the signal was weak in the respiratory tract. Single cell RNA-Seq data from trachea indicated positive signals along the respiratory tract in key protective cell types including club, goblet, proliferating, and ciliary epithelial cells; while in lung the ratio of ACE2-expressing cells was low in all cell types (<2.6%), but was highest in vascular endothelial and goblet cells. Gene ontology analysis suggested that, besides its classical role in the renin-angiotensin system, ACE2 may be functionally associated with angiogenesis/blood vessel morphogenesis. Using a novel tool for the prediction of transcription factor binding sites we identified several putative binding sites within two tissue-specific promoters of the ACE2 gene as well as a new putative short form of ACE2. These include several interferon-stimulated response elements sites for STAT1, IRF8, and IRF9. Our results also confirmed that age and gender play no significant role in the regulation of ACE2 mRNA expression in the lung.

Venoms of Iranian Scorpions (Arachnida, Scorpiones) and Their Potential for Drug Discovery

Scorpions, a characteristic group of arthropods, are among the earliest diverging arachnids, dating back almost 440 million years. One of the many interesting aspects of scorpions is that they have venom arsenals for capturing prey and defending against predators, which may play a critical role in their evolutionary success. Unfortunately, however, scorpion envenomation represents a serious health problem in several countries, including Iran. Iran is acknowledged as an area with a high richness of scorpion species and families. The diversity of the scorpion fauna in Iran is the subject of this review, in which we report a total of 78 species and subspecies in 19 genera and four families. We also list some of the toxins or genes studied from five species, including Androctonus crassicauda, Hottentotta zagrosensis, Mesobuthus phillipsi, Odontobuthus doriae, and Hemiscorpius lepturus, in the Buthidae and Hemiscorpiidae families. Lastly, we review the diverse functions of typical toxins from the Iranian scorpion species, including their medical applications.

Proteomic Analyses of the Unexplored Sea Anemone Bunodactis verrucosa

Cnidarian toxic products, particularly peptide toxins, constitute a promising target for biomedicine research. Indeed, cnidarians are considered as the largest phylum of generally toxic animals. However, research on peptides and toxins of sea anemones is still limited. Moreover, most of the toxins from sea anemones have been discovered by classical purification approaches. Recently, high-throughput methodologies have been used for this purpose but in other Phyla. Hence, the present work was focused on the proteomic analyses of whole-body extract from the unexplored sea anemone Bunodactis verrucosa. The proteomic analyses applied were based on two methods: two-dimensional gel electrophoresis combined with MALDI-TOF/TOF and shotgun proteomic approach. In total, 413 proteins were identified, but only eight proteins were identified from gel-based analyses. Such proteins are mainly involved in basal metabolism and biosynthesis of antibiotics as the most relevant pathways. In addition, some putative toxins including metalloproteinases and neurotoxins were also identified. These findings reinforce the significance of the production of antimicrobial compounds and toxins by sea anemones, which play a significant role in defense and feeding. In general, the present study provides the first proteome map of the sea anemone B. verrucosa stablishing a reference for future studies in the discovery of new compounds.

Melatonin, advanced oxidation protein products and total antioxidant capacity as seminal parameters of prooxidant-antioxidant balance and their connection with expression of metalloproteinases in context of male fertility

Currently, in highly developed, industrialized countries male factors are identified as the primary cause of infertility in about 60% of childless couples. Standard semen analysis parameters, such as sperm morphology, number and motility, are important in predicting the fertility of large populations, but they are not sufficient to fully specify a particular donor sperm's ability to fertilize the egg. The semen also comprises components, which may also affect sperm fertilizing ability and which have thus far remained little explored: the biochemical parameters of the seminal plasma secreted by the testis, the seminiferous tubules and the prostate gland, such as: matrix metalloproteinases (MMP-2 and MMP-9) and their specific tissue inhibitors (TIMP-1 and TIMP-2). We highlight the need for a better determination of prooxidant-antioxidant balance parameters such as: melatonin, advanced oxidation protein products (AOPPs) and total antioxidant capacity (TAC) in human semen when establishing the diagnostics of male subfertility or infertility. We also discuss their connection with seminal plasma metalloproteinases and their inhibitors. In particular, we believe that the cumulative and synergic effects of the sperm redox parameters on male fertility need to be better explored and we suggest that they should be studied in conjunction with other biologically active parameters of the ejaculate such as the expression of metalloproteinases and their tissue inhibitors. This will enable a better understanding of how their correlated effects impact semen condition.

Pilot-Scale Production and Thermostability Improvement of the M23 Protease Pseudoalterin from the Deep Sea Bacterium Pseudoalteromonas sp. CF6-2

Pseudoalterin is the most abundant protease secreted by the marine sedimental bacterium Pseudoalteromonas sp. CF6-2 and is a novel cold-adapted metalloprotease of the M23 family. Proteases of the M23 family have high activity towards peptidoglycan and elastin, suggesting their promising biomedical and biotechnological potentials. To lower the fermentive cost and improve the pseudoalterin production of CF6-2, we optimized the fermentation medium by using single factor experiments, added 0.5% sucrose as a carbon source, and lowered the usage of artery powder from 1.2% to 0.6%. In the optimized medium, pseudoalterin production reached 161.15 ± 3.08 U/mL, 61% greater than that before optimization. We further conducted a small-scale fermentation experiment in a 5-L fermenter and a pilot-scale fermentation experiment in a 50-L fermenter. Pseudoalterin production during pilot-scale fermentation reached 103.48 ± 8.64 U/mL, 77% greater than that before the medium was optimized. In addition, through single factor experiments and orthogonal tests, we developed a compound stabilizer for pseudoalterin, using medically safe sugars and polyols. This stabilizer showed a significant protective effect for pseudoalterin against enzymatic thermal denaturation. These results lay a solid foundation for the industrial production of pseudoalterin and the development of its biomedical and biotechnological potentials.

Culture Condition Optimization and Pilot Scale Production of the M12 Metalloprotease Myroilysin Produced by the Deep-Sea Bacterium Myroides profundi D25

The protease myroilysin is the most abundant protease secreted by marine sedimental bacterium Myroides profundi D25. As a novel elastase of the M12 family, myroilysin has high elastin-degrading activity and strong collagen-swelling ability, suggesting its promising biotechnological potential. Because myroilysin cannot be maturely expressed in Escherichia coli, it is important to be able to improve the production of myroilysin in the wild strain D25. We optimized the culture conditions of strain D25 for protease production by using single factor experiments. Under the optimized conditions, the protease activity of strain D25 reached 1137 ± 53.29 U/mL, i.e., 174% of that before optimization (652 ± 23.78 U/mL). We then conducted small scale fermentations of D25 in a 7.5 L fermentor. The protease activity of strain D25 in small scale fermentations reached 1546.4 ± 82.65 U/mL after parameter optimization. Based on the small scale fermentation results, we further conducted pilot scale fermentations of D25 in a 200 L fermentor, in which the protease production of D25 reached approximately 1100 U/mL. These results indicate that we successfully set up the small and pilot scale fermentation processes of strain D25 for myroilysin production, which should be helpful for the industrial production of myroilysin and the development of its biotechnological potential.

[Peculiarities of Proteus mirabilis extracellular metalloproteinase biosynthesis]

Biosynthesis of metalloproteinase by the Proteus mirabilis 5127-1 strain on different media and the influence of glucose and urea on biosynthesis were studied. It was found that the P. mirabilis 5127-1 bacteria secretes metalloproteinase in the medium in two isoforms (52 and 50 kDa). It was established that proteinase synthesis is completely suppressed during the growth of bacteria on synthetic media, as well as in the presence of LB glucose in the medium. It was demonstrated that addition of urea in the medium results in an increase of the culture productivity in the proteinase synthesis. Maximal culture productivity in the proteinase synthesis was found in the medium with natural urine. During the growth of bacteria on artificial urine, proteinase appeared in the medium only after 12 hours of growth as a single isoform.

Enhanced in vitro formation and antibiotic resistance of nonattached Pseudomonas aeruginosa aggregates through incorporation of neutrophil products

Pseudomonas aeruginosa is a major pathogen in cystic fibrosis (CF) lung disease. Children with CF are routinely exposed to P. aeruginosa from the natural environment, and by adulthood, 80% of patients are chronically infected. P. aeruginosa in the CF airway exhibits a unique biofilm-like structure, where it grows in small clusters or aggregates of bacteria in association with abundant polymers of neutrophil-derived components F-actin and DNA, among other components. These aggregates differ substantially in size and appearance compared to surface-attached in vitro biofilm models classically utilized for studies but are believed to share properties of surface-attached biofilms, including antibiotic resistance. However, little is known about the formation and function of surface-independent modes of biofilm growth, how they might be eradicated, and quorum sensing communication. To address these issues, we developed a novel in vitro model of P. aeruginosa aggregates incorporating human neutrophil-derived products. Aggregates grown in vitro and those found in CF patients' sputum samples were morphologically similar; viable bacteria were distributed in small pockets throughout the aggregate. The lasA quorum sensing gene was differentially expressed in the presence of neutrophil products. Importantly, aggregates formed in the presence of neutrophils acquired resistance to tobramycin, which was lost when the aggregates were dispersed with DNase, and antagonism of tobramycin and azithromycin was observed. This novel yet simple in vitro system advances our ability to model infection of the CF airway and will be an important tool to study virulence and test alternative eradication strategies against P. aeruginosa.

Transforming growth factor-beta and matrix metalloproteinases: functional interactions in tumor stroma-infiltrating myeloid cells

Transforming growth factor-beta (TGF-β) is a pleiotropic factor with several different roles in health and disease. In tumorigenesis, it may act as a protumorigenic factor and have a profound impact on the regulation of the immune system response. Matrix metalloproteinases (MMPs) are a family that comprises more than 25 members, which have recently been proposed as important regulators acting in tumor stroma by regulating the response of noncellular and cellular microenvironment. Tumor stroma consists of several types of resident cells and infiltrating cells derived from bone marrow, which together play crucial roles in the promotion of tumor growth and metastasis. In cancer cells, TGF-β regulates MMPs expression, while MMPs, produced by either cancer cells or residents' stroma cells, activate latent TGF-β in the extracellular matrix, together facilitating the enhancement of tumor progression. In this review we will focus on the compartment of myeloid stroma cells, such as tumor-associated macrophages, neutrophils, and dendritic and mast cells, which are potently regulated by TGF-β and produce large amounts of MMPs. Their interplay and mutual implications in the generation of pro-tumorigenic cancer microenvironment will be analyzed.

EMMPRIN is secreted by human uterine epithelial cells in microvesicles and stimulates metalloproteinase production by human uterine fibroblast cells

Endometrial remodeling is a physiological process involved in the gynecological disease, endometriosis. Tissue remodeling is directed by uterine fibroblast production of matrix metalloproteinases (MMPs). Several MMPs are regulated directly by the protein extracellular matrix metalloproteinase inducer (EMMPRIN) and also by proinflammatory cytokines such as interleukin (IL)1-α/β. We hypothesized that human uterine epithelial cells (HESs) secrete intact EMMPRIN to stimulate MMPs. Microvesicles from HES cell-conditioned medium (CM) expressed intact EMMPRIN protein. Treatment of HES cells with estradiol or phorbyl 12-myristate-13-acetate increased the release of EMMPRIN-containing microvesicles. The HES CM stimulated MMP-1, -2, and -3 messenger RNA levels in human uterine fibroblasts (HUFs) and EMMPRIN immunodepletion from HES-cell concentrated CM reduced MMP stimulation (P < .05). Treatment of HUF cells with low concentrations of IL-1β/α stimulated MMP production (P < .05). These results indicate that HES cells regulate MMP production by HUF cells by secretion of EMMPRIN, in response to ovarian hormones, proinflammatory cytokines as well as activation of protein kinase C.

Differential expression of cruzipain- and gp63-like molecules in the phytoflagellate trypanosomatid Phytomonas serpens induced by exogenous proteins

Phytomonas serpens synthesizes metallo- and cysteine-proteases that are related to gp63 and cruzipain, respectively, two virulence factors produced by pathogenic trypanosomatids. Here, we described the cellular distribution of gp63- and cruzipain-like molecules in P. serpens through immunocytochemistry and confocal fluorescence microscopy. Both proteases were detected in distinct cellular compartments, presenting co-localization in membrane domains and intracellular regions. Subsequently, we showed that exogenous proteins modulated the production of both protease classes, but in different ways. Regarding the metalloprotease, only fetal bovine serum (FBS) influenced the gp63 expression, reducing its surface exposition (≈30%). Conversely, the cruzipain-like molecule was differentially modulated according to the proteins: human and bovine albumins reduced its expression around 50% and 35%, respectively; mucin and FBS did not alter its production, while IgG and hemoglobin drastically enhanced its surface exposition around 7- and 11-fold, respectively. Additionally, hemoglobin induced an augmentation in the cell-associated cruzipain-like activity in a dose-dependent manner. A twofold increase of the secreted cruzipain-like protein was detected after parasite incubation with 1% hemoglobin compared to the parasites incubated in PBS-glucose. The results showed the ability of P. serpens in modulating the expression and the activity of proteolytic enzymes after exposition to exogenous proteins, with emphasis in its cruzipain-like molecules.

[Snake venom metalloproteinases: structure, biosynthesis and function(s)]

The biochemical and the pharmacological characterization of snake venoms revealed an important structural and functional polymorphism of proteins which they contain. Among them, snake venom metalloproteases (SVMPs) constitute approximatively 20 to 60% of the whole venom proteins. During the last decades, a significant progress was performed against structure studies and the biosynthesis of the SVMPs. Indeed, several metalloproteases were isolated and characterized against their structural and pharmacological properties. In this review, we report the most important properties concerning the classification, the structure of the various domains of the SVMPs as well as their biosynthesis and their activities as potential therapeutic agents.

Expression, purification and characterization of recombinant Jerdonitin, a P-II class snake venom metalloproteinase comprising metalloproteinase and disintegrin domains

Jerdonitin is a P-II class snake venom metalloproteinase comprising metalloproteinase and disintegrin domains. In this study, we established a high-level expression system in Pichia pastoris and developed a purification strategy for the recombinant Jerdonitin. This recombinant Jerdonitin degraded fibrinogen at a level of activity comparable with its wild type. The effects of recombinant Jerdonitin on inhibiting ADP-induced human platelet aggregation were in a dose-dependent manner with an IC(50) of 248nM. In addition, we reported here that Jerdonitin can significantly inhibit the growth of several cell lines, including human liver cancer cells (Bel7402), human leukemia cells (K562) and human gastric carcinoma cells (BGC823). This study offers recombinant Jerdonitin that will be valuable for further functional and structural studies of Jerdonitin.

Sulfasalazine blocks the release of proteoglycan and collagen from cytokine stimulated cartilage and down-regulates metalloproteinases

OBJECTIVE

To investigate the effect of SSZ on the release of GAG and collagen fragments from bovine nasal cartilage and MMP and ADAMTS (a disintegrin and metalloproteinase domain with thrombospondin motifs) proteinases from human articular chondrocytes (HACs) stimulated with IL-1alpha and oncostatin M (OSM).

METHODS

SSZ was added to bovine nasal explant cultures stimulated to resorb with IL-1alpha and OSM, and the release of GAG and collagen has been determined. Collagenolytic activity was measured using the radio-labelled collagen bioassay. HACs were treated with IL-1alpha and OSM with and without SSZ, and MMP-1 and -13 and ADAMTS-4 and -5 were measured for protein and gene expression by ELISA and RT-PCR, respectively.

RESULTS

SSZ blocked GAG and collagen fragment release from bovine cartilage, and reduced active and total collagenase activity in a dose-dependent manner. SSZ transcriptionally blocked MMP-1, -13 and ADAMTS-4, and reduced the protein levels of MMP-1 and -13 in a dose-dependent manner following stimulation of HACs with IL-1alpha and OSM.

CONCLUSION

This study shows for the first time that SSZ blocks release of proteoglycan and collagen fragments from resorbing cartilage and lowers the levels of proteoglycan and collagen-degrading enzymes. These results indicate that in addition to acting as an anti-inflammatory agent, SSZ may have a therapeutic role in protecting cartilage from damage in OA.

Invasion front-specific overexpression of tissue inhibitor of metalloproteinase-1 in liver metastases from colorectal cancer

BACKGROUND

Matrix metalloproteinases (MMPs) and their inhibitors, the tissue inhibitors of metalloproteinases (TIMPs), have been implicated in invasion and metastasis. The distribution of MMPs and TIMPs in the invasion front of liver metastases from colorectal cancer were investigated in order to understand their potential role in invasiveness.

MATERIALS AND METHODS

Freshly frozen material of colorectal metastases of the liver was microdissected into four separate compartments, namely pure liver, liver invasion, tumour invasion and pure tumour. RNA was isolated and analyzed on Affymetrix microarrays. Expression of TIMP-1 was confirmed by quantitative polymerase chain reaction in 10 colorectal liver metastases. Cellular localisation of TIMP-1 was examined by immunohistochemistry.

RESULTS

Affymetrix microarray data revealed that several MMP and TIMP genes including MMP-2, -3, -7, -9, -11, -12, -14, -15, -16, -19 and -24, and TIMP-1, -2 and -3 were generally up-regulated in both invasion front compartments. Among these genes, TIMP-1 showed the highest expression. The qPCR results indicated an average 15-fold upregulation of TIMP-1 in the liver invasive front and an average 13-fold up-regulation in the tumor invasive front, each compared to normal liver tissue. Immunohistochemistry revealed expression of TIMP-1 in tumour epithelia as well as in host tissue cells, including fibroblastic cells.

CONCLUSION

Our data indicate that tumour invasion in colorectal liver metastasis is associated with increased TIMP-1 RNA and protein levels in both tumour and host cells.

Production of an extracellular alkaline metalloprotease from a newly isolated, moderately halophile, Salinivibrio sp. strain AF-2004

An extracellular protease was produced under stress conditions of high temperature and high salinity by a newly isolated moderate halophile, Salinivibrio sp. strain AF-2004 in a basal medium containing peptone, beef extract, glucose and NaCl. A modification of Kunitz method was used for protease assay. The isolate was capable of producing protease in the presence of sodium chloride, sodium sulfate, sodium nitrate, sodium nitrite, potassium chloride, sodium acetate and sodium citrate. The maximum protease was secreted in the presence of 7.5 to 10% (w/v) sodium sulfate or 3% (w/v) sodium acetate (4.6 U ml(-1)). Various carbon sources including glucose, lactose, casein and peptone were capable of inducing enzyme production. The optimum pH, temperature and aeration for enzyme production were 9.0, 32 degrees C and 220 rpm, respectively. The enzyme production corresponded with growth and reached a maximum level during the mid-stationary phase. Maximum protease activity was exhibited in the medium containing 1% (w/v) NaCl at 60 degrees C, with 18% and 41% activity reductions at temperature 50 and 70 degrees C, respectively. The optimum pH for enzyme activity was 8.5, with 86% and 75% residual activities at pH 10 and 6, respectively. The activity of enzyme was inhibited by EDTA. These results suggest that the protease secreted by Salinivibrio sp. strain AF-2004 is industrially important from the perspectives of its activity at a broad pH ranges (5.0-10.0), its moderate thermoactivity in addition to its high tolerance to a wide range of salt concentration (0-10% NaCl).

Growth plate zonal microarray analysis shows upregulation of extracellular matrix genes and downregulation of metalloproteinases and cathepsins following irradiation

Although the growth plate matrix area fraction increases after irradiation, extracellular matrix (ECM) gene expression in this context has not been studied. The hypothesis was that normally expressed ECM genes would be upregulated after irradiation. The right limbs of six Sprague-Dawley 5-week-old rats were irradiated with the left limbs as controls. Half of the animals were harvested after 1 week and half after 2. Microarray was conducted from normal and irradiated tibial growth plate proliferative zone (PZ) and hypertrophic zone (HZ) chondrocytes separated by laser microdissection at each time point. In situ hybridization (ISH) and real-time polymerase chain reaction (PCR) were used to confirm expression of selected genes. At 1 and 2 weeks after irradiation, both normally expressed ECM genes and others not highly expressed in the normal growth plate showed upregulation. Metalloproteinases and cathepsins were downregulated. PZ gene expression after irradiation exhibited features of the normal HZ, suggesting premature terminal differentiation. ECM genes not highly expressed in the normal growth plate included several members of the small leucine-rich proteins and the ezrin-radixin-moesin family. The effects of irradiation on cathepsin K (Ctsk), integrin binding sialoprotein (Ibsp), and procollagen II alpha 1 (Col2a1), as determined by ISH and real-time PCR, were highly correlated with the microarray results. Accumulation of matrix following radiation injury to the growth plate correlated well with changes in gene expression. Upregulation of genes not normally highly expressed in the noninjured growth plate suggests their importance in the injury and repair response.

Production of Vibrio vulnificus metalloprotease VvpE begins during the early growth phase: Usefulness of gelatin-zymography

Recent studies have demonstrated that expression of the vvpE gene begins during the early growth phase albeit at low levels. However, we found that the traditional protease assay method that is used to measure caseinolytic activity in culture supernatants is not suitable for the measurement of extracellular VvpE that is produced at low levels during the early growth phase. By using gelatin-zymography in place of the protease assay, we could specifically detect only VvpE of several proteases produced by Vibrio vulnificus. Moreover, we could sensitively measure VvpE produced at low levels during the early growth phase, which was consistent with transcription of the vvpE gene. The extracellular production of VvpE was reduced or delayed by mutation of the pilD gene which encodes for the type IV leader peptidase/N-methyltransferase associated with the type II general secretion system; the delayed production of VvpE was recovered by in trans complementation of the wild-type pilD gene. These results indicate that VvpE begins to be produced during the early growth phase via the PilD-mediated type II general secretion system, and that the use of gelatin-zymography is recommended as a simple method for the sensitive and specific detection of VvpE production.

Post-antifungal effects of the antifungal compound 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate on Aspergillus fumigatus

The post-antifungal effect (PAFE) of the antifungal compound 2-(3,4-dimethyl-2,5-dihydro-1H-pyrrol-2-yl)-1-methylethyl pentanoate (DHP) upon Aspergillus fumigatus was investigated. The conidia of A. fumigatus were exposed to DHP at concentrations of 1× and 4× MIC90 for variable times at 37 °C. Amphotericin B (AmB)-treated or drug-free controls were included in the study. DHP as well as AmB exposure resulted in prolonged lag phases of the turbidimetric growth curves. Both the treatments gave rise to delayed growth, with lag phases of 11 h upon treatment with a concentration of 4× MIC90 for 4 h. Furthermore, it was observed that DHP inhibited the expression of three A. fumigatus secretory proteins of 18, 42 and 55 kDa. One protein of 42 kDa was found to be a metalloprotease, which is an important virulence factor. Analysis of time-dependent antigenic profiles showed the early expression of high-molecular-mass antigens. Expression of low-molecular-mass antigens started after 24 h culture. The antigens of A. fumigatus that are expressed during the early phase of growth were observed to be adversely affected after treatment with DHP. Although the mechanism of action of DHP to inhibit these proteins/antigens is unknown, the observations may be valuable to understand their role in the virulence of the pathogen, as well as the antigen-mediated responses caused by A. fumigatus.

Analysis of normal and osteoarthritic canine cartilage mRNA expression by quantitative polymerase chain reaction

The molecular basis to mammalian osteoarthritis (OA) is unknown. We hypothesised that the expression of selected proteases, matrix molecules, and collagens believed to have a role in the pathogenesis of OA would be changed in naturally occurring canine OA cartilage when compared to normal articular cartilage. Quantitative (real-time) reverse transcriptase-polymerase chain reaction assays were designed measuring the expression of selected matrix molecules (collagens and small leucine-rich proteoglycans), key mediators of the proteolytic degradation of articular cartilage (metalloproteinases, cathepsins), and their inhibitors (tissue inhibitors of matrix metalloproteinases). All data were normalised using a geometric mean of three housekeeping genes, and the results subjected to power calculations and corrections for multiple hypothesis testing. We detected increases in the expression of BGN, COL1A2, COL2A1, COL3A1, COL5A1, CSPG2, CTSB, CTSD, LUM, MMP13, TIMP1, and TNC in naturally occurring canine OA. The expression of TIMP2 and TIMP4 was significantly reduced in canine OA cartilage. The patterns of gene expression change observed in naturally occurring canine OA were similar to those reported in naturally occurring human OA and experimental canine OA. We conclude that the expression profiles of matrix-associated molecules in end-stage mammalian OA may be comparable but that the precise aetiologies of OA affecting specific joints in different species are presently unknown.

Fxna, a novel gene differentially expressed in the rat ovary at the time of folliculogenesis, is required for normal ovarian histogenesis

In rodents, the formation of ovarian follicles occurs after birth. In recent years, several factors required for follicular assembly and the growth of the newly formed follicles have been identified. We now describe a novel gene, Fxna, identified by differential display in the neonatal rat ovary. Fxna encodes an mRNA of 5.4 kb, and a protein of 898 amino acids. Fxna is a transmembrane metallopeptidase from family M28, localized to the endoplasmic reticulum. In the ovary, Fxna mRNA is expressed in granulosa cells; its abundance is maximal 48 hours after birth, i.e. during the initiation of follicular assembly. Reducing Fxna mRNA levels via lentiviral-mediated delivery of short hairpin RNAs to neonatal ovaries resulted in substantial loss of primordial, primary and secondary follicles, and structural disorganization of the ovary, with many abnormal follicles containing more than one oocyte and clusters of somatic cells not associated with any oocytes. These abnormalities were not attributable to either increased apoptosis or decreased proliferation of granulosa cells. The results indicate that Fxna is required for the organization of somatic cells and oocytes into discrete follicular structures. As an endoplasmic reticulum-bound peptidase, Fxna may facilitate follicular organization by processing precursor proteins required for intraovarian cell-to-cell communication.

Signaling mechanism of thrombin-induced gingival fibroblast-populated collagen gel contraction

1.--Thrombin is activated during gingival tissue injury and inflammation. Thrombin (platelet)-rich plasma has been used for periodontal regeneration with success. Thrombin and other bacterial proteases also affect the functions of adjacent periodontal cells via stimulation of protease-activated receptors (PARs). 2.--We noted that thrombin (0.1-2 U ml(-1)), human, and frog PAR-1 agonist peptide (20-240 microM) induced the gingival fibroblast (GF)-populated collagen gel contraction within 2 h of exposure. However, PAR-2, PAR-3, and PAR-4 agonist peptide (20-240 microM) showed little effect on collagen gel contraction. U73122 (phospholipase C inhibitor) and 2-APB (IP3 antagonist) were effective in inhibition of GF contraction. 3.--Thrombin-induced GF contraction was inhibited by 5 mM EGTA (an extracellular calcium chelator) and verapamil (an L-type calcium channel blocker). In addition, W7 (10 and 25 microM, a calcium/calmodulin (CaM) inhibitor), ML-7 (50 microM, myosin light chain kinase (MLCK) inhibitor), and HA1077 (100 microM, Rho kinase inhibitor) completely inhibited the thrombin-induced collagen gel contraction. Thrombin also induced the phosphorylation of ERK1/ERK2 and elevated the Rho-GTP levels in GF. 4.--However, U0126 only partially inhibited the thrombin-induced GF contraction. Similarly, wortmannin (100 nM), LY294002 (20 microM) (two PI3K inhibitor) and genistein also showed partial inhibition. Moreover, NAC was not able to suppress the GF contraction, as supported by the slight decrease in reactive oxygen species production in GF by thrombin. 5.--Thrombin also stimulated metalloproteinase-2 (MMP-2) and MMP-3 production in GF. But addition of GM6001 or 1,10-phenanthroline, two MMP inhibitors, could not inhibit the thrombin-induced GF contraction. 6.--These results indicate that thrombin is crucial in the periodontal inflammation and wound healing by promoting GF contraction. This event is mainly mediated via PAR-1 activation, PLC activation, extracellular calcium influx via L-type calcium channel, and the calcium/CaM-MLCK and Rho kinase activation pathway.

Metalloproteinases Control Brain Inflammation Induced by Pertussis Toxin in Mice Overexpressing the Chemokine CCL2 in the Central Nervous System

Inflammatory leukocytes infiltrate the CNS parenchyma in neuroinflammation. This involves cellular migration across various structures associated with the blood-brain barrier: the vascular endothelium, the glia limitans, and the perivascular space between them. Leukocytes accumulate spontaneously in the perivascular space in brains of transgenic (Tg) mice that overexpress CCL2 under control of a CNS-specific promoter. The Tg mice show no clinical symptoms, even though leukocytes have crossed the endothelial basement membrane. Pertussis toxin (PTx) given i.p. induced encephalopathy and weight loss in Tg mice. We used flow cytometry, ultra-small superparamagnetic iron oxide-enhanced magnetic resonance imaging, and immunofluorescent staining to show that encephalopathy involved leukocyte migration across the glia limitans into the brain parenchyma, identifying this as the critical step in inducing clinical symptoms. Metalloproteinase (MPs) enzymes are implicated in leukocyte infiltration in neuroinflammation. Unmanipulated Tg mice had elevated expression of tissue inhibitor of metalloproteinase-1, matrix metalloproteinase (MMP)-10, and -12 mRNA in the brain. PTx further induced expression of tissue inhibitor of metalloproteinase-1, metalloproteinase disintegrins-12, MMP-8, and -10 in brains of Tg mice. Levels of the microglial-associated MP MMP-15 were not affected in control or PTx-treated Tg mice. PTx also up-regulated expression of proinflammatory cytokines IL-1beta and TNF-alpha mRNA in Tg CNS. Weight loss and parenchymal infiltration, but not perivascular accumulation, were significantly inhibited by the broad-spectrum MP inhibitor BB-94/Batimastat. Our finding that MPs mediate PTx-induced parenchymal infiltration to the chemokine-overexpressing CNS has relevance for the pathogenesis of human diseases involving CNS inflammation, such as multiple sclerosis.

In vitro metacestodicidal activities of genistein and other isoflavones against Echinococcus multilocularis and Echinococcus granulosus

Echinococcus multilocularis and Echinococcus granulosus metacestode infections in humans cause alveolar echinococcosis and cystic echinococcosis, respectively, in which metacestode development in visceral organs often results in particular organ failure. Further, cystic hydatidosis in farm animals causes severe economic losses. Although benzimidazole derivatives such as mebendazole and albendazole are being used as therapeutic agents, there is often no complete recovery after treatment. Hence, in searching for novel treatment options, we examined the in vitro efficacies of a number of isoflavones against Echinococcus metacestodes and protoscoleces. The most prominent isoflavone, genistein, exhibits significant metacestodicidal activity in vitro. However, genistein binds to the estrogen receptor and can thus induce estrogenic effects, which is a major concern during long-term chemotherapy. We have therefore investigated the activities of a number of synthetic genistein derivatives carrying a modified estrogen receptor binding site. One of these, Rm6423, induced dramatic breakdown of the structural integrity of the metacestode germinal layer of both species within 5 to 7 days of in vitro treatment. Further, examination of the culture medium revealed increased leakage of parasite proteins into the medium during treatment, but zymography demonstrated a decrease in the activity of metalloproteases. Moreover, two of the genistein derivatives, Rm6423 and Rm6426, induced considerable damage in E. granulosus protoscoleces, rendering them nonviable. These findings demonstrate that synthetic isoflavones exhibit distinct in vitro effects on Echinococcus metacestodes and protoscoleces, which could potentially be exploited further for the development of novel chemotherapeutical tools against larval-stage Echinococcus infection.

Gasoline exhaust emissions induce vascular remodeling pathways involved in atherosclerosis

Epidemiological evidence indicates that environmental air pollutants are positively associated with the development of chronic vascular disease; however, the mechanisms involved have not been fully elucidated. In the present study we examined molecular pathways associated with chronic vascular disease in atherosclerosis-prone apolipoprotein E-deficient (ApoE(-/-)) mice, including markers of vascular remodeling and oxidative stress, in response to exposure to the ubiquitous environmental pollutant, gasoline engine emissions. ApoE(-/-) mice, on a high-fat diet, were exposed by inhalation to either filtered air; 8, 40, or 60 mug/m(3) particulate matter whole exhaust; or filtered exhaust with gases matching the 60-mug/m(3) concentration, for 7 weeks. Aortas and plasma were collected and assayed for changes in histochemical markers, real-time reverse transcriptase-polymerase chain reaction, and indicators of oxidative damage. Inhalational exposure to gasoline engine emissions resulted in increased aortic mRNA expression of matrix metalloproteinase-3 (MMP-3), MMP-7, and MMP-9, tissue inhibitor of metalloproteinases-2, endothelin-1 and heme oxygenase-1 in ApoE(-/-) mice; increased aortic MMP-9 protein levels were confirmed through immunohistochemistry. Elevated reactive oxygen species were also observed in arteries from exposed animals, despite absence of plasma markers. Similar findings were also observed in the aortas of ApoE(-/-) mice exposed to particle-filtered atmosphere, implicating the gaseous components of the whole exhaust in mediating the expression of markers associated with the vasculopathy. These findings demonstrate that exposure to gasoline engine emissions results in the transcriptional upregulation of factors associated with vascular remodeling, as well as increased markers of vascular oxidative stress, which may contribute to the progression of atherosclerosis and reduced stability of vulnerable plaques.

Lagochilascaris minor third-stage larvae secrete metalloproteases with specificity for fibrinogen and native collagen

Dissemination of parasitic infections depends on migration through tissues and evasion from both hemostatic processes and immune responses from hosts. Metalloproteases play major roles in these mechanisms of pathogen-host interactions and, thus, are considered drug targets. In this study, we characterized metalloprotease activities in excretory/secretory (ES) products from third stage larvae (L3) of the ascarid Lagochilascaris minor, the causative agent of lagochilascariosis, which demonstrates an impressive migrating capacity across host tissues, including bone. Gel enzymography showed that ES products of L3 display two major gelatinolytic activities. Optimal proteolytic activity was found to occur at neutral/alkaline pH and was associated with two L. minor-secreted metalloproteases of 59 (SM59(Lm)) and 114kDa (SM114(Lm)). We next showed that ES products of L3 were able to hydrolyze fibrinogen and collagen I at neutral pH, but not BSA, in an extensive manner. Furthermore, we demonstrated that ES products of L3 mediate hydrolysis of the triple helical structure of collagen I fibers in mouse mesentery. These results suggest that ES proteases of L3 might facilitate both L. minor migration through host tissues by hydrolyzing collagens of the extracellular matrix and evasion from host hemostatic mechanisms by degrading fibrinogen.

Transcription levels of invasion-related genes in prostate cancer cells are modified by inhibitors of tyrosine kinase

Previous reports have shown that genistein and tyrphostin AG-1478, two tyrosine kinase inhibitors (TKIs), exert multiple cellular effects in prostate carcinoma cells, e.g. a reduction in the production of urokinase plasminogen activator (uPA) and its receptor uPAR, and a decrease in the cells' ability to invade an artificial basement membrane. Microarray technology was used to measure alterations in mRNA levels caused by TKI treatment in two prostatic carcinoma cell lines, PC-3 and DU-145. Genistein treatment led to a reduction of at least 50% in 78 genes in PC-3, while 82 were twofold upregulated. In DU-145, the same treatment resulted in a 50% decreased transcript level in 120 genes, and increased expression in 25 genes. Tyrphostin AG-1478 produced a 50% reduction in mRNA levels in 58 genes in DU-145, whereas no alterations were demonstrated using the tyrphostin in PC-3 cells. Among the effects of TKIs, a lowered uPA and uPAR transcription was demonstrated in genistein-treated cells, while a few metalloproteinases (MMPs) were affected. Transcription of various integrin subunits was also downregulated overall. Several alterations in gene transcription were demonstrated in PC-3 and DU-145 after TKI treatment. This knowledge could be of importance in the search for new therapeutic strategies in prostate cancer treatment, and the interplay between the various effects needs to be investigated further.

Vipera lebetina venom contains all types of snake venom metalloproteases

Snake venoms contain four classes of metalloproteases that all have a typical zinc-chelating sequence (HEXXHGXXH). N-terminal sequences and internal sequences of different purified metalloproteases were determined using Edman sequencing and LC MS/MS technique. Oligonucleotides were designed and used as primers for cDNA cloning from Vipera lebetina venom gland cDNA library. We found that isoforms of fibrinolytic enzyme lebetase Le-4 and Le-3 are synthesized in different way: Le-4 is synthesized as P-I type metalloprotease, Le-3 is synthesized with disintegrin-like domain as P-II type protease and processed post-translationally. An endothelial cell apoptosis-inducing heterodimeric glycosylated metalloprotease, V. lebetina apoptosis-inducing protease (VLAIP), belongs to P-III type containing metalloprotease, disintegrin-like and cysteine-rich domains. All these enzymes hydrolyze the Aalpha-chain and more slowly the Bbeta-chain of fibrinogen. Treatment of HUVEC cells with VLAIP induces changes in the attachment of cells to the substrate and causes apoptosis. V. lebetina venom contains also P-IV type-specific coagulant factor X activator (VLFXA) that cleaves the Arg52-Ile53 bond in the heavy chain of human factor X. VLFXA is a glycoprotein composed of a heavy chain and two C-type lectin-like light chains linked by disulfide bonds. The heavy and light chains of VLFXA are synthesized from different genes.

Expression and processing of Vibrio anguillarum zinc-metalloprotease in Escherichia coli

The extracellular zinc-metalloprotease of Vibrio anguillarum is a secreted virulence factor. It is synthesized from the empA gene as a 611-residue preproprotease and processed to the active mature protease (EmpA) with concomitant secretion via the type II secretion pathway. Active EmpA has been found only in the V. anguillarum culture supernatant and the process of the activation seems to vary depending on strains analyzed. To better understand the mechanism of EmpA export and processing, the empA gene was cloned and expressed in Escherichia coli strains. Expression of empA did not have toxic effect on bacterial growth. Rupturing E. coli TOP10 cells by heating in gel-loading buffer resulted in activation of EmpA and severe proteolysis of the samples. In contrast, the same treatment of the E. coli MC4100A strain did not lead to the general proteolysis. In this strain, EmpA was exported into the periplasm via the Sec pathway. The periplasmic EmpA was detected in two active conformations. Therefore, in E. coli processing of EmpA precursor to an active enzyme did not require secretion to the media and the help of other V. anguillarum protein. Like in V. anguillarum, heterologous expression of empA in E. coli showed strain-specific activation process.

Absence of p300 induces cellular phenotypic changes characteristic of epithelial to mesenchyme transition

p300 is a transcriptional cofactor and prototype histone acetyltransferase involved in regulating multiple cellular processes. We generated p300 deficient (p300⁻) cells from the colon carcinoma cell line HCT116 by gene targeting. Comparison of epithelial and mesenchymal proteins in p300⁻ with parental HCT116 cells showed that a number of genes involved in cell and extracellular matrix interactions, typical of ‘epithelial to mesenchyme transition’ were differentially regulated at both the RNA and protein level. p300⁻ cells were found to have aggressive ‘cancer’ phenotypes, with loss of cell–cell adhesion, defects in cell–matrix adhesion and increased migration through collagen and matrigel. Although migration was shown to be metalloproteinase mediated, these cells actually showed a downregulation or no change in the level of key metalloproteinases, indicating that changes in cellular adhesion properties can be critical for cellular mobility.

Pseudallescheria boydii releases metallopeptidases capable of cleaving several proteinaceous compounds

Pseudallescheria boydii is an opportunistic filamentous fungus that causes serious infections in humans. Virulence attributes expressed by P. boydii are unknown. Conversely, peptidases are incriminated as virulence factors in several pathogenic fungi. Here we investigated the extracellular peptidase profile in P. boydii. After growth on Sabouraud for 7 days, mycelia of P. boydii were incubated for 20 h in PBS-glucose. The cell-free PBS-glucose supernatant was submitted to SDS-PAGE and 12 secretory polypeptides were observed. Two of these polypeptides (28 and 35 kD) presented proteolytic activity when BSA was used as a copolymerized substrate. The extracellular peptidases were most active in acidic pH (5.5) and fully inhibited by 1,10-phenanthroline, a zinc-metallopeptidase inhibitor. Other metallo-, cysteine, serine and aspartic proteolytic inhibitors did not significantly alter these activities. To confirm that these enzymes belong to the metallo-type peptidases, the apoenzymes were obtained by dialysis against chelating agents, and supplementation with different cations, especially Cu(2+) and Zn(2+), restored their activities. Except for gelatin, both metallopeptidases hydrolyzed various co-polymerized substrates, including human serum albumin, casein, hemoglobin and IgG. Additionally, the metallopeptidases were able to cleave different soluble proteinaceous substrates such as extracellular matrix components and sialylated proteins. All these hydrolyses were inhibited by 1,10-phenanthroline. Interestingly, Scedosporium apiospermum (the anamorph of P. boydii) produced a distinct extracellular peptidase profile. Collectively, our results demonstrated for the first time the expression of acidic extracellular metallopeptidases in P. boydii capable of degrading several proteinaceous compounds that could help the fungus to escape from natural human barriers and defenses.

Overexpression and mechanistic characterization of blastula protease 10, a metalloprotease involved in sea urchin embryogenesis and development

Blastula protease 10 (BP10) is a metalloenzyme involved in sea urchin embryogenesis, which has been assigned to the astacin family of zinc-dependent endopeptidases. It shows greatest homology with the mammalian tolloid-like genes and contains conserved structural motifs consistent with astacin, tolloid, and bone morphogenetic protein 1. Astacin, a crustacean digestive enzyme, has been proposed to carry out hydrolysis via a metal-centered mechanism that involves a metal-coordinated "tyrosine switch." It has not been determined if the more structurally complex members of this family involved in eukaryotic development share this mechanism. The recombinant BP10 has been overexpressed in Escherichia coli, its metalloenzyme nature has been confirmed, and its catalytic properties have been characterized through kinetic studies. BP10 shows significant hydrolysis toward gelatin both in its native zinc-containing form and copper derivative. The copper derivative of BP10 shows a remarkable 960% rate acceleration toward the hydrolysis of the synthetic substrate N-benzoyl-arginine-p-nitroanilide when compared with the zinc form. The enzyme also shows calcium-dependent activation. These are the first thorough mechanistic studies reported on BP10 as a representative of the more structurally complex members of astacin-type enzymes in deuterostomes, which can add supporting data to corroborate the metal-centered mechanism proposed for astacin and the role of the coordinated Tyr. We have demonstrated the first mechanistic study of a tolloid-related metalloenzyme involved in sea urchin embryogenesis.

Interleukin-10 does not affect IL-1-induced interleukin-6 and metalloproteinase production in human chondrosarcoma cells, SW1353

Cartilage repair by transplantation of autologous chondrocytes is an option when restoring functional joints. Control of chondrocyte function is thus required. Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine affecting the expression of a wide range of immune mediators in hematopoietic and non-hematopoietic cells. Previous studies indicated that IL-10 has therapeutic potential in the treatment of chronic inflammatory joint disorders such as rheumatoid arthritis and osteoarthritis. IL-10 has been found to be chondroprotective by down-regulating metalloproteinase expression and by inhibiting the synthesis of pro-inflammatory cytokines, such as IL-6, in immune cells. In contrast, the effects of IL-10 on chondrocytes are poorly understood and have to be identified with regard to their future clinical use. In this study, we investigated the effects of IL-10 on the expression of cartilage-degrading mediators in the human chondrosarcoma cell line, SW1353, after exposure to IL-1, a key mediator in cartilage and bone destruction. We found a strong induction of the pro-inflammatory cytokine, IL-6, in IL-1-exposed SW1353 cells. Surprisingly, IL-10 had no effect on IL-1-induced IL-6, pro-MMP1, and pro-MMP13 secretion. Although RT-PCR analyses demonstrated the expression of both receptor chains of the IL-10 receptor complex (IL-10R1 and IL-10R2), exposure of SW1353 to IL-10 did not lead to phosphorylation of STAT3, the major transcription factor induced by IL-10. This was not due to a defect in STAT3, because stimulation with IL-6 resulted in its phosphorylation. Failure of SW1353 cells to respond to IL-10 was consistent with a deficient surface expression of IL-10R1. From these results we conclude that IL-10 does not exert its chondroprotective character on chondrocytes directly. Furthermore, the unresponsiveness of chondrocytes towards IL-10 might explain the vulnerability of joint cartilage to inflammation.

Phosphodiesterase type 4 expression and anti-proliferative effects in human pulmonary artery smooth muscle cells

Background

Pulmonary arterial hypertension is a proliferative vascular disease, characterized by aberrant regulation of smooth muscle cell proliferation and apoptosis in distal pulmonary arteries. Prostacyclin (PGI₂) analogues have anti-proliferative effects on distal human pulmonary artery smooth muscle cells (PASMCs), which are dependent on intracellular cAMP stimulation. We therefore sought to investigate the involvement of the main cAMP-specific enzymes, phosphodiesterase type 4 (PDE4), responsible for cAMP hydrolysis.

Methods

Distal human PASMCs were derived from pulmonary arteries by explant culture (n = 14, passage 3–12). Responses to platelet-derived growth factor-BB (5–10 ng/ml), serum, PGI₂ analogues (cicaprost, iloprost) and PDE4 inhibitors (roflumilast, rolipram, cilomilast) were determined by measuring cAMP phosphodiesterase activity, intracellular cAMP levels, DNA synthesis, apoptosis (as measured by DNA fragmentation and nuclear condensation) and matrix metalloproteinase-2 and -9 (MMP-2, MMP-9) production.

Results

Expression of all four PDE4A-D genes was detected in PASMC isolates. PDE4 contributed to the main proportion (35.9 ± 2.3%, n = 5) of cAMP-specific hydrolytic activity demonstrated in PASMCs, compared to PDE3 (21.5 ± 2.5%), PDE2 (15.8 ± 3.4%) or PDE1 activity (14.5 ± 4.2%). Intracellular cAMP levels were increased by PGI₂ analogues and further elevated in cells co-treated with roflumilast, rolipram and cilomilast. DNA synthesis was attenuated by 1 μM roflumilast (49 ± 6% inhibition), rolipram (37 ± 6%) and cilomilast (30 ± 4%) and, in the presence of 5 nM cicaprost, these compounds exhibited EC₅₀ values of 4.4 (2.6–6.1) nM (Mean and 95% confidence interval), 59 (36–83) nM and 97 (66–130) nM respectively. Roflumilast attenuated cell proliferation and gelatinase (MMP-2 and MMP-9) production and promoted the anti-proliferative effects of PGI₂ analogues. The cAMP activators iloprost and forskolin also induced apoptosis, whereas roflumilast had no significant effect.

Conclusion

PDE4 enzymes are expressed in distal human PASMCs and the effects of cAMP-stimulating agents on DNA synthesis, proliferation and MMP production is dependent, at least in part, on PDE4 activity. PDE4 inhibition may provide greater control of cAMP-mediated anti-proliferative effects in human PASMCs and therefore could prove useful as an additional therapy for pulmonary arterial hypertension.

Resuscitation of hypoxic piglets with 100% O2 increases pulmonary metalloproteinases and IL-8

We hypothesized that resuscitation with 100% O2 compared with 21% O2 is detrimental to pulmonary tissue. The pulmonary injury was assessed by matrix metalloproteinase (MMP) activity, oxidative stress, IL-8, and histology 2.5 h after resuscitation from a hypoxic state. In pulmonary tissue extracts, MMP activity was analyzed by broad matrix-degrading capacity (total MMP) and zymography. MMP-2 mRNA expression was evaluated by quantitative real-time PCR. Total endogenous antioxidant capacity was measured by the oxygen radical absorbance capacity (ORAC) assay, and IL-8 was analyzed by ELISA technique. In bronchoalveolar lavage (BAL) fluid, MMPs were analyzed by zymography. In pulmonary tissue, pro- and active MMP-2 levels were increased in piglets that were resuscitated with 100% O2 compared with 21% O2. Pro-MMP-9, total MMP activity, and MMP-2 mRNA levels were significantly increased in resuscitated piglets compared with baseline. Net gelatinolytic activity increased in submucosa and blood vessels after 100% O2 and only in the blood vessels after 21% O2. Compared with baseline, ORAC values were considerably lowered in the resuscitated piglets and significantly reduced in the 100% O2 versus 21% O2 group. In BAL fluid, both pro-MMP-9 and pro-MMP-2 increased 2-fold in the 100% O2 group compared with 21% O2. Moreover, IL-8 concentration increased significantly in piglets that were resuscitated with 100% O2 compared with 21% O2, suggesting a marked proinflammatory response in the pulmonary tissue. Altogether, these data strongly suggest that caution must be taken when applying pure O2 to the newborn infant.

Genistein suppresses the invasive potential of human breast cancer cells through transcriptional regulation of metalloproteinases and their tissue inhibitors

Progression of breast cancer implicates the degradation of extracellular matrix (ECM) by metallo-proteinases (MMPs), a process with important consequences on the growth and invasiveness of cancer cells in adjacent and distant sites. The isoflavone, genistein--a natural inhibitor of protein tyrosine kinase pathway--inhibits the growth of a wide range of cancer cells in vitro. The aim of this study was to investigate: i) the expression of mRNAs encoded for MMPs and their endogenous inhibitors (TIMPs) associated with pathogenesis and metastatic potential of breast cancer cells; and ii) the effect of genistein on the transcription of MMPs and TIMPs and the invasive potential of breast cancer cells. Gene expression at transcriptional level was examined in cell cultures of two epithelial breast cancer cell lines, the high invasive (ER-negative) MDA-MB-231 and the low invasive (ER-positive) MCF-7, as well as the normal mammary cells (MCF-12A) following RNA isolation and reversed transcriptase polymerase chain reaction (RT-PCR). The inhibitory effect of genistein on functional invasiveness was examined by a cell invasion assay. Cell cycle distribution showed that genistein arrested breast cancer MDA-MB-231, MCF-7 and BT-20 cells in the G2/M phase. Both normal and breast cancer cell lines express the genes of MMP-2, -9, MT1-, MT2-, MT3-MMP and TIMP-1, -2 and -3. MCF-7 express notably less MMPs than MDA-MB-231 cell line. The addition of genistein resulted in down-regulation of the transcription of all MMP genes in MDA-MB-231 and most of MMPs in MCF-7 cells. The inhibitory effect of genistein on MMPs was functionally confirmed, since it significantly reduced the invasion properties of cancer cells in vitro. The obtained results indicate that genistein may be of great value in prevention of breast cancer cell metastasis, since it represents both a transcriptional modulator of genes involved in this pathogenetic process and a suppressor of breast cancer cell invasiveness.

Roles of the multifunctional glycoprotein, emmprin (basigin; CD147), in tumour progression

Emmprin (basigin;CD147) is a widely distributed cell surface glycoprotein that belongs to the Ig superfamily and is highly enriched on the surface of malignant tumour cells. Emmprin is involved in numerous physiological and pathological systems and exhibits several molecular and cellular characteristics, but a major function of emmprin is stimulation of synthesis of several matrix metalloproteinases. In tumours, emmprin most likely stimulates matrix metalloproteinase production in stromal fibroblasts and endothelial cells as well as in tumour cells themselves by a mechanism involving homophilic interactions between emmprin molecules on apposing cells or on neighbouring cells after membrane vesicle shedding. Membrane-associated cofactors, including caveolin-1 and annexin II, regulate emmprin activity. Emmprin induces angiogenesis via stimulation of VEGF production, invasiveness via stimulation of matrix metalloproteinase production and multidrug resistance via hyaluronan-mediated up-regulation of ErbB2 signaling and cell survival pathway activities. Although the detailed mechanisms whereby it regulates these numerous phenomena are not yet known, it is clear that emmprin is a major mediator of malignant cell behavior.

Vibrio vulnificusmetalloprotease VvpE has no direct effect on the iron-assimilation from human holotransferrin

In order to elucidate the role of Vibrio vulnificus metalloprotease VvpE in the uptake of iron from human transferrin, we constructed a VvpE-deficient mutant and a merozygotic vvpE-transcriptional reporter from the wild type strain MO6-24/O. All three strains were able to grow only in deferrated Heart Infusion broth (DF-HI) with human holotransferrin (HT), but not in DF-HI containing partially iron-saturated transferrin or apotransferrin, without noticeable differences among the strains. All strains consumed most iron in the early growth phase. Both the transcription and extracellular production of VvpE proceeded at undetectable levels when bacterial growth was severely retarded in the DF-HI. When HT or FeCl(3) was added to the DF-HI, the retarded bacterial growth was restored and vvpE transcription dramatically increased in the late growth phase, but the extracellular VvpE production was negligible as compared to its transcription. All strains were unable to degrade HT even in normal HI broth containing HT, in which extracellular VvpE activity was remarkably high. The uptake of iron from HT in all strains was consistent with the production of catechol-siderophore rather than hydroxamate-siderophore. Similar results were also observed when clinical isolates from septicemic patients were used. In conclusion, we determined that VvpE was not directly involved in the siderophore-mediated iron-uptake from human transferrin. In addition, the discrepancy between the transcription and extracellular production of VvpE suggests that additional posttranscriptional events are involved in the extracellular production of VvpE.

NADPH-oxidase-driven oxygen radical production determines chondrocyte death and partly regulates metalloproteinase-mediated cartilage matrix degradation during interferon-gamma-stimulated immune complex arthritis

In previous studies we have found that FcγRI determines chondrocyte death and matrix metalloproteinase (MMP)-mediated cartilage destruction during IFN-γ-regulated immune complex arthritis (ICA). Binding of immune complexes (ICs) to FcγRI leads to the prominent production of oxygen radicals. In the present study we investigated the contribution of NADPH-oxidase-driven oxygen radicals to cartilage destruction by using p47phox^-/- mice lacking a functional NADPH oxidase complex. Induction of a passive ICA in the knee joints of p47phox^-/- mice resulted in a significant elevation of joint inflammation at day 3 when compared with wild-type (WT) controls as studied by histology. However, when IFN-γ was overexpressed by injection of adenoviral IFN-γ in the knee joint before ICA induction, a similar influx of inflammatory cells was found at days 3 and 7, comprising mainly macrophages in both mouse strains. Proteoglycan depletion from the cartilage layers of the knee joints in both groups was similar at days 3 and 7. Aggrecan breakdown in cartilage caused by MMPs was further studied by immunolocalisation of MMP-mediated neoepitopes (VDIPEN). VDIPEN expression in the cartilage layers of arthritic knee joints was markedly lower (between 30 and 60%) in IFN-γ-stimulated arthritic p47phox^-/- mice at day 7 than in WT controls, despite significant upregulation of mRNA levels of various MMPs such as MMP-3, MMP-9, MMP-12 and MMP-13 in synovia and MMP-13 in cartilage layers as measured with quantitative RT-PCR. The latter observation suggests that oxygen radicals are involved in the activation of latent MMPs. Chondrocyte death, determined as the percentage of empty lacunae in articular cartilage, ranged between 20 and 60% at day 3 and between 30 and 80% at day 7 in WT mice, and was completely blocked in p47phox^-/- mice at both time points. FcγRI mRNA expression was significantly lower, and FcγRII and FcγRIII were higher, in p47phox^-/- mice than in controls. NADPH-oxidase-driven oxygen radical production determines chondrocyte death and aggravates MMP-mediated cartilage destruction during IFN-γ-stimulated IC-mediated arthritis. Upregulation of FcγRI by oxygen radicals may contribute to cartilage destruction.

Characterization of (2R, 3S)-2-([[4-(2-butynyloxy)phenyl]sulfonyl]amino)-N,3-dihydroxybutanamide, a potent and selective inhibitor of TNF-alpha converting enzyme

TNF-alpha converting enzyme (TACE) is a validated therapeutic target for the development of oral tumor necrosis factor-alpha (TNF-alpha) inhibitors. Here we report the pre-clinical results and characterization of a selective and potent TACE inhibitor, (2R, 3S)-2-([[4-(2-butynyloxy)phenyl]sulfonyl]amino)-N,3-dihydroxybutanamide (TMI-2), in various in vitro and in vivo assays. TMI-2 is a potent TACE inhibitor in an enzymatic FRET assay (IC50=2 nM). It is more than 250-fold selective over MMP-1, -7, -9, -14, and ADAM-10 in vitro. In cell-based assays and human whole blood, TMI-2 inhibits lipopolysaccharide (LPS)-induced TNF secretion with IC50s<1 uM. Importantly, TMI-2 inhibits the spontaneous release of TNF-alpha in human synovium tissue explants of rheumatoid arthritis patients with an IC50 of 0.8 microM. In vivo, TMI-2 potently inhibits LPS-induced TNF-alpha production in mice (ED50=3 mg/kg). In the adjuvant-induced arthritis (AIA) model in rats, treatment with TMI-2 at 30 mg/kg and 100 mg/kg p.o. b.i.d. was highly effective in reducing joint arthritis scores. In a semi-therapeutic collagen-induced arthritis (CIA) model in mice, TMI-2 is highly effective in reducing disease severity scores after oral treatment at 100 mg/kg twice per day. In summary, TMI-2 is a potent and selective TACE inhibitor that inhibits TNF-alpha production and reduces the arthritis scores in pre-clinical models. TMI-2 represents a novel class of TACE inhibitors that may be effective and beneficial in the treatment of rheumatoid arthritis as well as other TNF-mediated inflammatory autoimmune diseases.

Suppressive activity of fexofenadine hydrochloride on metalloproteinase production from nasal fibroblasts in vitro

BACKGROUND

Allergic rhinitis (AR) is an inflammatory disease characterized by nasal wall remodelling with intense infiltration of eosinophils and mast cells/basophils. Matrix metalloproteinases (MMPs), MMP-2 and MMP-9, are the major proteolytic enzymes that induce airway remodelling. These enzymes are also important in the migration of inflammatory cells through basement membrane components.

OBJECTIVE

We evaluated whether fexofenadine hydrochloride (FEX), the carboxylic acid metabolite of terfenadine with selective H(1)-receptor antagonist activity, could inhibit MMP production from nasal fibroblasts (NFs) in response to TNF-alpha stimulation in vitro.

METHODS

NFs were established from nasal polyp-derived fibroblasts (PFs) taken from patients with AR. Nasal mucosal fibroblasts (MFs) were also induced from nasal mucosal tissues from septal deformity patients without allergy. PF and MF (2 x 10(5) cells/mL, each) were stimulated with TNF-alpha in the presence of various concentrations of FEX. After 24 h, culture supernatants were obtained and assayed for MMP-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 levels by ELISA. The influence of FEX on mRNA expression of MMPs and TIMPs in 4 h-cultured cells was also evaluated by real-time RT-PCR. Furthermore, nuclear factor-kappa B (NF-kappa B) activation in fibroblasts treated with FEX for 4 h was examined by ELISA.

RESULTS

FEX at more than 350 ng/mL inhibited the production of MMP-2 and MMP-9 from both PF and MF in response to TNF-alpha stimulation, whereas TIMP-1 and TIMP-2 production was scarcely affected by FEX. FEX also inhibited MMP mRNA expression and NF-kappa B activation in PF and MF after TNF-alpha stimulation.

CONCLUSION

The present data suggest that the attenuating effect of FEX on MMP-2 and -9 production from NFs induced by inflammatory stimulation may underlie the therapeutic mode of action of the agent on allergic diseases, including AR.

Molecular cloning, functional expression, and molecular modeling of bothrostatin, a new highly active disintegrin from Bothrops jararaca venom

Disintegrins are among the most potent antagonists of several integrins. A cDNA encoding a novel disintegrin, bothrostatin, was cloned from a Bothrops jararaca cDNA library. The precursor of bothrostatin contains a pro, a metalloproteinase, and an RGD-disintegrin domain. The disintegrin domain expressed in Escherichia coli showed high inhibitory activity on collagen-induced platelet aggregation (IC(50) of 12nM), and thus it can be used as a useful tool for studies of integrin-ligand interaction. Furthermore, we used the comparative modeling approach to obtain a model of the 3D structure of bothrostatin. Our results suggest that bothrostatin adopts a globular, closed structure in solution. The RGD motif is exposed to the solution by the loop formed by residues 45-59 and is very close to the C-terminal domain forming a finger-like structure. The proximity of the RGD loop and the C-terminal residues, which is maintained by the Cys47-Cys66 bond, suggests that the C-terminal residues are involved in the ability of bothrostatin to interact with its ligands.

[Identification of psychrotrophs SYP-A2-3 producing cold-adapted protease from the No. 1 Glacier of China and study on its fermentation conditions]

The psychrotrophs SYP-A2-3 producing the cold-adapted protease has been isolated from the bacterial samples collected from the No. 1 Glacier of China and identified as Bacillus cereus according to its morphological and physiochemical characteristics and 16s rDNA gene sequence analysis. It could grow between 0 degree C and 38 degrees C while its optimal growth temperature was 25 degrees C and the optimal temperature for its protease production was 15 degrees C. The cold-adapted protease was identified as neutral metallo-protease, the molecular weight was 34.2 kD shown by SDS-PAGE, the optimal pH and temperature for activity was 7.0-8.5 and 42 degrees C, respectively. Various fermentation conditions of its protease production were also investigated. The results showed that casein was the best nitrogen source while glucose and starch were suitable carbon source for its protease production. The initial pH of fermentation broth ranged from 6.5 to 7.0 was optimal. Under optimized conditions, the protease activity produced by SYP-A2-3 could reach 3800 U/mL and 4800 U/mL conducted in shaking flask and 5 L stirred jar experiment, respectively.

Histone deacetylase inhibitors modulate metalloproteinase gene expression in chondrocytes and block cartilage resorption

Cartilage destruction in the arthritides is thought to be mediated by two main enzyme families: the matrix metalloproteinases (MMPs) are responsible for cartilage collagen breakdown, and enzymes from the ADAMTS (a disintegrin and metalloproteinase domain with thrombospondin motifs) family mediate cartilage aggrecan loss. Many genes subject to transcriptional control are regulated, at least in part, by modifications to chromatin, including acetylation of histones. The aim of this study was to examine the impact of histone deacetylase (HDAC) inhibitors on the expression of metalloproteinase genes in chondrocytes and to explore the potential of these inhibitors as chondroprotective agents. The effects of HDAC inhibitors on cartilage degradation were assessed using a bovine nasal cartilage explant assay. The expression and activity of metalloproteinases was measured using real-time RT-PCR, western blot, gelatin zymography, and collagenase activity assays using both SW1353 chondrosarcoma cells and primary human chondrocytes. The HDAC inhibitors trichostatin A and sodium butyrate potently inhibit cartilage degradation in an explant assay. These compounds decrease the level of collagenolytic enzymes in explant-conditioned culture medium and also the activation of these enzymes. In cell culture, these effects are explained by the ability of HDAC inhibitors to block the induction of key MMPs (e.g. MMP-1 and MMP-13) by proinflammatory cytokines at both the mRNA and protein levels. The induction of aggrecan-degrading enzymes (e.g. ADAMTS4, ADAMTS5, and ADAMTS9) is also inhibited at the mRNA level. HDAC inhibitors may therefore be novel chondroprotective therapeutic agents in arthritis by virtue of their ability to inhibit the expression of destructive metalloproteinases by chondrocytes.

A conserved metalloprotease mediates ecdysis in Caenorhabditis elegans

Molting is required for progression between larval stages in the life cycle of nematodes. We have identified four mutant alleles of a Caenorhabditis elegans metalloprotease gene, nas-37, that cause incomplete ecdysis. At each molt the cuticle fails to open sufficiently at the anterior end and the partially shed cuticle is dragged behind the animal. The gene is expressed in hypodermal cells 4 hours before ecdysis during all larval stages. The NAS-37 protein accumulates in the anterior cuticle and is shed in the cuticle after ecdysis. This pattern of protein accumulation places NAS-37 in the right place and at the right time to degrade the cuticle to facilitate ecdysis. The nas-37 gene has orthologs in other nematode species, including parasitic nematodes, and they undergo a similar shedding process. For example, Haemonchus contortus molts by digesting a ring of cuticle at the tip of the nose. Incubating Haemonchus larvae in extracted exsheathing fluids causes a refractile ring of digested cuticle to form at the tip of the nose. When Haemonchus cuticles are incubated with purified NAS-37, a similar refractile ring forms. NAS-37 degradation of the Haemonchus cuticle suggests that the metalloproteases and the cuticle substrates involved in exsheathment of parasitic nematodes are conserved in free-living nematodes.

The effect of hindlimb immobilization on acid phosphatase, metalloproteinases and nuclear factor-κB in muscles of young and old rats

Age-associated muscle wasting (sarcopenia of old age) is a major problem in elderly people, however, the mechanisms of muscle proteolysis in aging remain obscure and enigmatic. Possible reasons for loss of skeletal muscle mass with aging may be attributed to multiple and complex proteolytic systems. The purpose of the present study was to explore the kinetics of activation of extracellular hydrolytic and proteolytic systems in muscles of hindlimbs immobilized by external fixation of 24-month-old female Wistar rats, in comparison with those of 6-month-old rats. Results show that elevated acid phosphatase activities (lysosomal hydrolytic enzyme activated mainly in macrophages) in immobilized limb muscles of young animals, differ from old animals. In young rats external fixation resulted in significantly elevated acid phosphatase activities (50-55%; p<0.05) after 4 weeks of immobilization, whereas in old animals similar increases were observed already during the first and second weeks of immobilization. The extracellular proteolytic enzymes, matrix metalloproteinases (MMP-2 and -9), were also differentially activated in old animals compared to young animals. In young animals, as shown in previous studies, both MMP-2 and -9 activities were elevated significantly in immobilized muscles. In this study of old animals, only MMP-2 activity was detected, with no significant elevation in the immobilized muscles of old animals. In addition, the levels of the transcription factor Nuclear Factor-kappaB (NF-kappaB) in nuclear extracts of old rat muscles, as detected by ELISA, showed a biphasic pattern after immobilization, suggesting that NF-kappaB could be activated by different processes in the atrophy process, at least in the old age. In conclusion, it seems that the kinetics of activation of extracellular hydrolytic and proteolytic systems differ in muscles of old animals compared to young animals.

The molecular pathophysiology of subacromial bursitis in rotator cuff disease

Little information exists on the molecular and biochemical pathophysiology of subacromial bursitis and rotator cuff disease. We investigated the pattern of expression of cytokines (interleukin [IL]-1beta, IL-1, IL-6, tumor necrosis factor [TNF] alpha, small inducible cytokines), metalloproteases, and cyclooxygenases in the subacromial bursa in patients with rotator cuff disease. Subacromial bursa specimens were prepared for molecular and biochemical analysis in patients undergoing shoulder surgery following an institutional review board-approved protocol. Specimens were analyzed for the presence of cytokines, metalloproteases, and cyclooxygenases by use of microarray for gene expression and immunohistocytochemistry. Microarray analysis for gene expression and immunohistochemistry demonstrated that the expression of several cytokine genes (TNF, IL-1alpha, IL-1beta, and IL-6) was increased in patients with subacromial bursitis compared with control specimens. Furthermore, the expression of metalloproteases (MMP-1 and MMP-9) and cyclooxygenases (COX-1 and COX-2) in the bursitis group was found to be increased as compared with controls. Although further investigation is required, these studies suggest that inflammation of the subacromial bursa does occur in patients with rotator cuff disease. These findings support the role of anti-inflammatory agents in the treatment of subacromial impingement and emphasize the importance of subacromial bursectomy to reduce inflammation in rotator cuff disease.

Oral treatment with PD-0200347, an ?2? ligand, reduces the development of experimental osteoarthritis by inhibiting metalloproteinases and inducible nitric oxide synthase gene expression and synthesis in cartilage chondrocytes

OBJECTIVE

To examine the in vivo effects of PD-0200347, an alpha(2)delta ligand of voltage-activated Ca(2+) channels and a compound chemically related to pregabalin and gabapentin, on the development of cartilage structural changes in an experimental dog model of osteoarthritis (OA). The effects of PD-0200347 on the major pathways involved in OA cartilage degradation, including matrix metalloproteinases (MMPs) and the inducible form of nitric oxide synthase (iNOS), were also studied.

METHODS

OA was surgically induced in dogs by sectioning the anterior cruciate ligament. OA dogs were randomly distributed into 3 groups and treated orally with either 1) placebo, 2) 15 mg/kg/day of PD-0200347, or 3) 90 mg/kg/day of PD-0200347. Dogs were killed 12 weeks after surgery. The severity of the lesions was scored macroscopically and histologically. Cartilage specimens from the femoral condyles and tibial plateaus were processed for RNA extraction and quantitative reverse transcription-polymerase chain reaction (RT-PCR) or immunohistochemistry. Specific probes and antibodies were used to study the messenger RNA and protein levels of iNOS, MMP-1, MMP-3, and MMP-13.

RESULTS

No clinical signs of drug toxicity were noted in the treated animals. Treatment with PD-0200347 at both dosages tested (15 and 90 mg/kg/day) reduced the development of cartilage lesions. There was a reduction in the score of lesions, with a statistically significant (P = 0.01) difference when the highest dosage of the drug was administered. The reduction in the score was mainly related to a decrease in the surface size of the lesions. Quantitative RT-PCR showed that PD-0200347 significantly reduced the expression of MMP-13, a key mediator in OA. Immunohistochemical analyses showed that treatment with PD-0200347 significantly reduced the synthesis of all key OA mediators studied.

CONCLUSION

This study demonstrated the efficacy of PD-0200347 in reducing the progression of cartilage structural changes in a dog model of OA. It also showed that this effect is linked to the inhibition of the major pathophysiologic mediators responsible for cartilage degradation.

Inhibition of glioma invasion by overexpression of pigment epithelium-derived factor

Pigment epithelium-derived factor (PEDF) is a potent inhibitor of angiogenesis and an inducer of neural differentiation. We previously reported the loss of PEDF expression in glioma progression. In this study, we investigated whether PEDF overexpression could suppress glioma growth and invasion. Glioma cell line U251 was stably transfected with a full-length human PEDF expression vector. The expression and release of various cytokines and angiogenic factors into the medium were analyzed by real-time reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, and gelatin zymography. Apoptosis was checked by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling. Growth inhibition was evaluated by using the in vitro Matrigel invasion. Tumorigenicity was examined in vivo by subcutaneous xenotransplantation into severe combined immunodeficient mice. In U251 cells overexpressing PEDF, thrombospondin-1 protein was upregulated (5.3-fold more), but the production of vascular endothelial growth factor (VEGF) (1.8-fold less) and basic fibroblast growth factor (2.5-fold less) was lower than in cells transfected with the vector only. PEDF also downregulated the production of matrix metalloproteinase-9. Conditioned medium collected from the PEDF-transfected U251 cells showed a significant reduction of VEGF expression. In vitro invasiveness was reduced by approximately 40%. PEDF expression prevented the growth of transfected cells and caused a significant increase in the percentage of cells undergoing apoptosis (50.4% in PEDF-transfected cells). Furthermore, the size of xenotransplants was significantly smaller. In conclusion, PEDF overexpression decreased malignancy, and this might be attributed to the promotion of apoptosis and the regulation of expression of angiogenic effectors. Thus, treatment with PEDF may be useful in patients with malignant gliomas. However, the mechanism of apoptosis induction needs to be investigated.

Recanalization of arterial thrombus, and inhibition with β-radiation in a new murine carotid occlusion model: mRNA expression of angiopoietins, metalloproteinases, and their inhibitors

BACKGROUND

Recanalization is an important physiologic phenomenon because it can efficiently reestablish circulation after thrombosis. We attempted to characterize molecular events related to recanalization or organization of arterial thrombus in a new murine model by studying genes reported to be involved in angiogenesis or neointima formation.

METHODS

Platinum coils, radioactive phosphorus 32 coils or not, were implanted in the carotid artery in mice to cause thrombotic occlusion. The outcome of the occlusion was followed up with transmyocardial angiography and pathologic analysis at 2, 6, or 15 days. Angiographic results were compared with the Pearson chi2 test. Messenger RNA expression of von Willebrand factor (vWF); smooth muscle alpha-actin (SMA+); platelet endothelial cell adhesion molecule-1 (PECAM-1); vascular endothelium cadherin (VE-Cad); endothelial nitric oxide synthase (eNOS); vascular cell adhesion molecule-1 (VCAM-1); tumor necrosis factor alpha (TNF-alpha); matrix metalloproteinase (MMP-9, MMP-12, and MMP-14), and tissue inhibitors of MMPs (TIMPs: TIMP-1, TIMP-2, TIMP-3, TIMP-4); angiopoietins (Ang-1, Ang-2); and receptors Tie-1 and Tie-2, were analyzed with reverse transcriptase polymerase chain reaction 2, 6, and 15 days after surgery. Levels of mRNA expression were compared with analysis of variance and the Student t test.

RESULTS

Carotid arteries implanted with nonradioactive 0.015-caliber coils were occluded in 84% of arteries on day 2, but in only 57% of arteries on day 15, which confirms that recanalization occurred in this model. Arteries implanted with 0.015-caliber 32P coils did not become recanalized, and 100% were occluded on day 15 (n = 13; P = .006). Recanalization was associated with endothelial-like cell-lined channels, whereas persistent occlusion was caused by complete filling of the lumen with conjunctive tissue. Coil occlusion, with or without recanalization, was followed by decreased expression of vWf, VE-Cad, eNOS, VCAM-1, MMP-2, TIMP-1, and TIMP-2; stable expression of PECAM-1, SMA+, and TIMP-3; and overexpression of Ang-1 and Ang-2, MMP-9, MMP-14, and TIMP-4. Statistically significant differences when arteries were implanted with 32P coils included decreased expression of TIMP-4 (P = .011) and increased expression of MMP-9 (P = .02).

CONCLUSION

Recanalization and organization of arterial thrombus is associated with expression of genes involved in angiogenesis and neointima formation. Recanalization can be prevented with beta-radiation, but molecular mechanisms remain to be refined.

CLINICAL RELEVANCE

A better understanding of molecular mechanisms involved in angiogenesis has permitted its regulation as a new option in treatment of various diseases. Inhibition of angiogenesis may help control diseases such as cancer, arthritis, or diabetes retinopathy. On the other hand, stimulation of angiogenesis may palliate conditions associated with insufficient blood supply, such as ischemic heart disease or critical limb ischemia. Yet little is known regarding recanalization (to be differentiated from thrombolysis), a cellular process that occurs concurrently with thrombus "organization." Recanalization is an important physiologic phenomenon because it can efficiently reestablish antegrade circulation after thrombosis both in veins and in arteries, and could be modulated for therapeutic purposes. Thus our efforts at better understanding of mechanisms involved in recanalization could be used, in addition to its promotion to recover flow after thrombotic occlusions, to prevent its occurrence after endovascular interventions designed to permanently occlude aneurysms.