Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.27.1 (RNase)
 16,360 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The activation of hepatic stellate cells (HSC) during liver fibrogenesis has been shown to be mediated by paracrine and autocrine loops involving transforming growth factor-beta1 (TGF-beta1) as the main fibrogenic mediator secreted by activated macrophages, endothelial cells and liberated by disintegrated platelets. The cell-associated plasminogen activation system regulates extracellular matrix (ECM) catabolism and cell movement. We have studied whether TGF-beta1 could modulate the plasminogen activation system in human HSC and the role of such protease system in the activity of TGF-beta1 on HSC. Urokinase plasminogen activator receptors (u-PAR), u-PA and plasminogen activator inhibitor type 1 (PAI-1) were determined by immunoassay and RNase protection assay. Cell migration, evaluated either as chemotaxis or as chemoinvasion, was studied in Boyden chambers after addition of TGF-beta1, and inhibition with anti-u-PA and anti-u-PAR antagonists [antibodies against u-PA and u-PAR and antisense oligonucleotides (aODN) against u-PAR mRNA]. We have shown that TGF-beta1 is not mitogenic for HSC, while it is a powerful motogen either in chemotaxis or chemoinvasion assays. TGF-beta1 up-regulates the synthesis and expression of PAI-1, as well as u-PAR expression and exposure at the cell membrane, while it does not affect u-PA levels. TGF-beta1-dependent chemoinvasion of reconstituted basement membrane exploits the cell-associated plasminogen activation system, since it is blocked by monoclonal antibodies against u-PA and against various u-PAR domains, as well as by anti-u-PAR aODN. We have also observed a cumulative effect of TGF-beta1, b-FGF and PDGF in the invasion assay of HSC: in the presence of low amounts of TGF-beta1 the chemoinvasive activity of PDGF and bFGF is dramatically increased. Also this cooperation requires u-PAR and is inhibited by monoclonal antibodies against u-PAR domains I, II and III.
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PMID:Transforming growth factor beta-1 stimulates invasivity of hepatic stellate cells by engagement of the cell-associated fibrinolytic system. 1176 74

The accumulation of fibrillar amyloid-beta protein (A beta) in cerebral blood vessels, a condition known as cerebral amyloid angiopathy (CAA), is a key pathological feature of Alzheimer's disease and certain related disorders and is intimately associated with cerebrovascular cell death both in vivo and in vitro. Moreover, severe CAA leads to loss of vessel wall integrity and cerebral hemorrhage. Although the basis for these latter pathological consequences in CAA remains unresolved alterations in local proteolytic mechanisms may be involved. Here we show that pathogenic forms of A beta stimulate the expression of plasminogen activator activity in cultured human cerebrovascular smooth muscle (HCSM) cells, an in vitro model of CAA. RNase protection assays and plasminogen zymography showed that urokinase-type plasminogen activator (uPA) was responsible for this activity. There was preferential accumulation of uPA on the HCSM cell surface that was mediated through a concomitant increase in expression of the uPA receptor. In the presence of plasminogen there was robust degradation of A beta that was added to the HCSM cells resulting in restoration of cell viability. This suggests that increased expression of uPA may initially serve as a protective mechanism leading to localized degradation and clearance of the pathogenic stimulus A beta. On the other hand, chronic expression of uPA and plasminogen activation led to a profound loss of HCSM cell attachment. This suggests that a similar prolonged effect in vivo in the cerebral vessel wall may contribute to loss of integrity and cerebral hemorrhage in CAA.
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PMID:Amyloid beta-protein stimulates the expression of urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in human cerebrovascular smooth muscle cells. 1275 71

Angiogenin is a member of the ribonuclease superfamily, which shows an ever expanding collection of molecules being identified and cloned. It was initially isolated from the conditioned medium of cultured tumour cells. Its angiogenic activity appears to be critical for the maintenance and support of tumour growth. Angiogenin also plays a role in a number of non-malignant vasculoproliferative pathological conditions. Along with other related molecules, it has been identified in a wide variety of somatic tissues in adult and embryonic stages of vertebrate development. This suggests that angiogenin and related molecules are likely to play a vital role in normal physiology. Angiogenin is detectable in serum and to date has been implicated as a mitogen for vascular endothelial cells, an immune modulator with suppressive effects on polymorphonuclear leukocytes, an activator of certain protease cascades such as matrix metalloproteases and plasminogen-activated plasmin pathways, as well as an adhesion molecule. However, the role of the angiogenin family in both normal and abnormal physiology and in development will only fully be realised by genetic approaches involving gene deletion.
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PMID:The angiogenins: an emerging family of ribonuclease related proteins with diverse cellular functions. 1451 18


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