937 resultados para 1-MATRIX METALLOPROTEINASE
Resumo:
Lung matrix homeostasis partly depends on the fine regulation of proteolytic activities. We examined the expression of human cysteine cathepsins (Cats) and their relative contribution to TGF-β1-induced fibroblast differentiation into myofibroblasts. Assays were conducted using both primary fibroblasts obtained from patients with idiopathic pulmonary fibrosis (IPF) and human lung CCD-19Lu fibroblasts. Pharmacological inhibition and genetic silencing of Cat B diminished α-smooth muscle actin expression, delayed fibroblast differentiation and led to an accumulation of intracellular 50-kDa TGF-β1. Moreover addition of Cat B generated 25-kDa mature form of TGF-β1 in Cat B siRNA-pretreated lysates. Inhibition of Cat B decreased Smad 2/3 phosphorylation, but had no effect on p38 MAPK and JNK phosphorylation indicating that Cat B mostly disturbs TGF-β1-driven canonical Smad signaling pathway. While mRNA expression of cystatin C was stable, its secretion, which was inhibited by brefeldin A, increased during TGF-β1-induced differentiation of IPF and CCD-19Lu fibroblasts. In addition cystatin C participated in the control of extracellular Cats, since its gene silencing restored their proteolytic activities. These data support the notion that Cat B participates in lung myofibrogenesis as suggested for stellate cells during liver fibrosis. Moreover, we propose that TGF-β1 promotes fibrosis by driving the effective cystatin C-dependent inhibition of extracellular matrix-degrading Cats.
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Neurodegenerative diseases affecting the macula constitute a major cause of incurable vision loss and exhibit considerable clinical and genetic heterogeneity, from early-onset monogenic disease to multifactorial late-onset age-related macular degeneration (AMD). As part of our continued efforts to define genetic causes of macular degeneration, we performed whole exome sequencing in four individuals of a two-generation family with autosomal dominant maculopathy and identified a rare variant p.Glu1144Lys in Fibrillin 2 (FBN2), a glycoprotein of the elastin-rich extracellular matrix (ECM). Sanger sequencing validated the segregation of this variant in the complete pedigree, including two additional affected and one unaffected individual. Sequencing of 192 maculopathy patients revealed additional rare variants, predicted to disrupt FBN2 function. We then undertook additional studies to explore the relationship of FBN2 to macular disease. We show that FBN2 localizes to Bruch's membrane and its expression appears to be reduced in aging and AMD eyes, prompting us to examine its relationship with AMD. We detect suggestive association of a common FBN2 non-synonymous variant, rs154001 (p.Val965Ile) with AMD in 10,337 cases and 11,174 controls (OR=1.10; p-value=3.79×10(-5)). Thus, it appears that rare and common variants in a single gene - FBN2 - can contribute to Mendelian and complex forms of macular degeneration. Our studies provide genetic evidence for a key role of elastin microfibers and Bruch's membrane in maintaining blood-retina homeostasis and establish the importance of studying orphan diseases for understanding more common clinical phenotypes.
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The R-matrix method describing the scattering of low-energy electrons by complex atoms and ions is extended to include terms of the Breit-Pauli Hamiltonian. An application is made to the astrophysically important 1s 2s S-1s 2s2p P transition in Fe XXIII, where in the most accurate calculations carried out all terms of the 1s 2s, 1s2s2p and 1s2p configurations are included in the expansion describing the collision. This gives up to 28 coupled channels for each total angular momentum and parity which are solved on a CRAY-1. The collision strengths are increased by more than a factor of two from their non-relativistic values at all energies considered.
Resumo:
Ongoing developments of the 2-D R-matrix propagator are discussed. These include application to electron and photon collisions with H-like ions; computational innovations; and important theoretical developments to enable the accurate treatment of electron and photon collisions with multi-electron atoms at intermediate energies.
Resumo:
We demonstrate the capability of ab initio time-dependent R-matrix theory to obtain accurate harmonic generation spectra of noble-gas atoms at near-IR wavelengths between 1200 and 1800 nm and peak intensities up to 1.8 × 10^(14) W/cm^(2). To accommodate the excursion length of the ejected electron, we use an angular-momentum expansion up to Lmax=279. The harmonic spectra show evidence of atomic structure through the presence of a Cooper minimum in harmonic generation for Kr, and of multielectron interaction through the giant resonance for Xe. The theoretical spectra agree well with those obtained experimentally.
Resumo:
How can we correlate the neural activity in the human brain as it responds to typed words, with properties of these terms (like ‘edible’, ‘fits in hand’)? In short, we want to find latent variables, that jointly explain both the brain activity, as well as the behavioral responses. This is one of many settings of the Coupled Matrix-Tensor Factorization (CMTF) problem.
Can we accelerate any CMTF solver, so that it runs within a few minutes instead of tens of hours to a day, while maintaining good accuracy? We introduce Turbo-SMT, a meta-method capable of doing exactly that: it boosts the performance of any CMTF algorithm, by up to 200x, along with an up to 65 fold increase in sparsity, with comparable accuracy to the baseline.
We apply Turbo-SMT to BrainQ, a dataset consisting of a (nouns, brain voxels, human subjects) tensor and a (nouns, properties) matrix, with coupling along the nouns dimension. Turbo-SMT is able to find meaningful latent variables, as well as to predict brain activity with competitive accuracy.
Resumo:
Glucagon-like peptide-1 (GLP-1) is an insulin-releasing hormone clinically exploited for glycaemic control in diabetes, which also confers acute cardioprotection and benefits in experimental/clinical heart failure. We specifically investigated the role of the GLP-1 mimetic, exendin-4, in post-myocardial infarction (MI) remodelling, which is a key contributor to heart failure. Adult female normoglycaemic mice underwent coronary artery ligation/sham surgery prior to infusion with exendin-4/vehicle for 4 weeks. Metabolic parameters and infarct sizes were comparable between groups. Exendin-4 protected against cardiac dysfunction and chamber dilatation post-MI and improved survival. Furthermore, exendin-4 modestly decreased cardiomyocyte hypertrophy/apoptosis but markedly attenuated interstitial fibrosis and myocardial inflammation post-MI. This was associated with altered extracellular matrix (procollagen IαI/IIIαI, connective tissue growth factor, fibronectin, TGF-β3) and inflammatory (IL-10, IL-1β, IL-6) gene expression in exendin-4-treated mice, together with modulation of both Akt/GSK-3β and Smad2/3 signalling. Exendin-4 also altered macrophage response gene expression in the absence of direct actions on cardiac fibroblast differentiation, suggesting cardioprotective effects occurring secondary to modulation of inflammation. Our findings indicate that exendin-4 protects against post-MI remodelling via preferential actions on inflammation and the extracellular matrix independently of its established actions on glycaemic control, thereby suggesting that selective targeting of GLP-1 signalling may be required to realise its clear therapeutic potential for post-MI heart failure.
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This paper investigates the inter-twining histories of two highly successful broadside ballads during the seventeenth century. Neither has been systematically studied before. A set of cultural relationships is opened for consideration by these songs: first, between the two ballads, which are different in several ways but set to the same tune; second, between the selected songs and other ballads on comparable themes; and third, between different editions of the two featured songs. In discussing each of these relationships, attention is paid not only to the texts but to the pictures and the tunes that helped to bring balladry to life for early-modern consumers. It is argued that balladry should be studied as an interconnected web and that individual publications drew significance from the manner in which they associated themselves – through shared pictures, tunes and narratives – with other examples of the genre.
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In this paper we present photoionization cross sections for the lowest five states of O-like S IX (1s(2)2s(2)2p(4) P-3(0,1,2), D-1(2), S-1(0)). The relativistic Breit-Pauli R-matrix codes were utilized including all terms of the 2s(2)2p(3), 2s2p(4), 2p(5), 2s(2)2p(2)3s, 3p, 3d and 2s2p(3)3s, 3p, 3d configurations in the expansion of the collision wavefunction for S X. It was also found that to achieve convergence of the low-lying energy separations of the target levels, an additional 21 configuration functions needed to be included in the configuration interaction expansion, incorporating two-electron excitations from the 2s and 2p shells to the 3s, 3p and 3d shells. The present work thus constitutes the most sophisticated photoionization evaluation for ground and metastable levels of the S IX ion. Direct comparisons have been made with the only available data found on the OPEN-ADAS database between level resolved contributions of the spectrum. This comparison for the background cross section exhibits excellent agreement at all photon energies for each partial photoionization cross section contribution investigated. Finally, the autoionizing bound states arising from numerous open channels have also been investigated and identified using the QB approach, a procedure for analyzing resonances in atomic and molecular collision theory which exploits the analytic properties of R-matrix theory. Major Rydberg resonance series are also presented and tabulated for the dominant linewidths considered.
Resumo:
The process involves encapsulation or immobilization of the active solid substance in a cellulose framework by regenerating cellulose dissolved in an ionic liq. solvent in a regenerating soln. The active substance can be initially present in the ionic liq. or in the regenerating solvent either as a soln. or dispersion. The invention is applicable to mol. encapsulation and to entrapping of larger particles including enzymes, nanoparticles and macroscopic components, and to the formation of bulk materials with a wide range of morphol. forms. Thus, carbamoylmethylphosphine oxide (I) encapsulated in a cellulose matrix was realized by adding I to a 10% soln. of cellulose in 1-butyl-3-methylimidazolium chloride (ionic liq.) under vigorous stirring and then removing the ionic liq. with water. [on SciFinder(R)]
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CD44 expression is elevated in basal-like breast cancer (BLBC) tissue, and correlates with increased efficiency of distant metastasis in patients and experimental models. We sought to characterize mechanisms underpinning CD44-promoted adhesion of BLBC cells to vascular endothelial monolayers and extracellular matrix (ECM) substrates. Stimulation with hyaluronan (HA), the native ligand for CD44, increased expression and activation of β1-integrin receptors, and increased α5-integrin subunit expression. Adhesion assays confirmed that CD44-signalling potentiated BLBC cell adhesion to endothelium and Fibronectin in an α5B1-integrin-dependent mechanism. Co-immunoprecipitation experiments confirmed HA-promoted association of CD44 with talin and the β1-integrin chain in BLBC cells. Knockdown of talin inhibited CD44 complexing with β1-integrin and repressed HA-induced, CD44-mediated activation of β1-integrin receptors. Immunoblotting confirmed that HA induced rapid phosphorylation of cortactin and paxillin, through a CD44-dependent and β1-integrin-dependent mechanisms. Knockdown of CD44, cortactin or paxillin independently attenuated the adhesion of BL-BCa cells to endothelial monolayers and Fibronectin. Accordingly, we conclude that CD44 induced, integrin-mediated signaling not only underpins efficient adhesion of BLBC cells to BMECs to facilitate extravasation but initiates their adhesion to Fibronectin, enabling penetrant cancer cells to adhere more efficiently to underlying Fibronectin-enriched matrix present within the metastatic niche.
Resumo:
PURPOSE: Some members of a novel series of pyrrolo-1,5-benzoxazepines (PBOXs) are microtubule-targeting agents capable of inducing apoptosis in a variety of human cancerous cells, hence, they are currently being developed as potential anti-cancer agents. The purpose of this study was to first characterise the activities of a novel PBOX analogue, PBOX-16 and then investigate the anti-angiogenic potential of both PBOX-16 and its prototype PBOX-6.
METHODS: The effects of PBOX-6 and -16 on cancerous cells (chronic myeloid leukaemia K562 cells and ovarian carcinoma A2780 cells) and primary cultured human umbilical vein endothelial cells (HUVECs) were examined by assessing cell proliferation, microtubular organisation, DNA analysis of cell cycle progression and caspase-3/7 activity. Their anti-angiogenic properties were then investigated by examining their ability to interfere with HUVEC differentiation into capillary-like structures and vascular endothelial growth factor (VEGF)-stimulated HUVEC migration.
RESULTS: PBOX-6 and -16 inhibited proliferation of K562, A2780 and HUVEC cells in a concentration-dependent manner. PBOX-16, confirmed as a novel depolymerising agent, was approximately tenfold more potent than PBOX-6. Inhibition of cell proliferation was mediated by G(2)/M arrest followed by varying degrees of apoptosis depending on the cell type; endothelial cells underwent less apoptosis than either of the cancer cell lines. In addition to the antitumourigenic properties, we also describe a novel antiangiogenic function for PBOXs: treatment with PBOXs inhibited the spontaneous differentiation of HUVECs into capillary-like structures when grown on a basement membrane matrix preparation (Matrigel™) and also significantly reduced VEGF-stimulated HUVEC migration.
CONCLUSION: Dual targeting of both the tumour cells and the host endothelial cells by PBOX compounds might enhance the anti-cancer efficacy of these drugs.
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The matrix metalloproteinases (MMPs) are endopeptidases which break down the extracellular matrix and regulate cytokine and growth factor activity. Several MMPs have been implicated in the promotion of invasion and metastasis in a broad range of tumours including urothelial carcinoma. In this study, RNA from 132 normal bladder and urothelial carcinoma specimens was profiled for each of the 24 human MMPs, the four endogenous tissue inhibitors of MMPs (TIMPs) and several key growth factors and their receptors using quantitative real time RT-PCR. Laser capture microdissection (LCM) of RNA from 22 tumour and 11 normal frozen sections was performed allowing accurate RNA extraction from either stromal or epithelial compartments. This study confirms the over expression in bladder tumour tissue of well-documented MMPs and highlights a range of MMPs which have not previously been implicated in the development of urothelial cancer. In summary, MMP-2, MT1-MMP and the previously unreported MMP-28 were very highly expressed in tumour samples while MMPs 1, 7, 9, 11, 15, 19 and 23 were highly expressed. There was a significant positive correlation between transcript expression and tumour grade for MMPs 1, 2, 8, 10, 11, 12, 13, 14, 15 and 28 (P < 0.001). At the same confidence interval, TIMP-1 and TIMP-3 also correlated with increasing tumour grade. LCM revealed that most highly expressed MMPs are located primarily within the stromal compartment except MMP-13 which localised to the epithelial compartment. This work forms the basis for further functional studies, which will help to confirm the MMPs as potential diagnostic and therapeutic targets in early bladder cancer.
Resumo:
Glucagon-like peptide-1 (GLP-1) is an endogenous peptide hormone whose metabolic effects have been exploited for glycaemic control in diabetes, but which also exerts important cardiovascular actions. We have recently reported that the GLP-1 mimetic, exendin-4, exerts clear benefits post-myocardial infarction via specific effects on extracellular matrix remodelling which is dysregulated in the diabetic heart (Robinson E et al, Basic Res Cardiol 2015; 110: 20), and have now shown similar cardioprotective actions in experimental diabetes, which are mediated via direct effects on infiltrating macrophages (Tate M et al, Basic Res Cardiol 2015; in press). Taken together with the apparent complexity of GLP-1 signalling and disappointing results of recent cardiovascular trials, our work strongly suggests that selective targeting of GLP-1 may be required in order to realise therapeutic benefit for both diabetic and non-diabetic heart failure patients. This is particularly important given the epidemic increase in the incidence of diabetes which is associated with a markedly enhanced susceptibility to cardiovascular stress.