Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.23 (beta-galactosidase)
 14,648 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our laboratory has been testing the hypothesis that genetic modulation of the beta-adrenergic signaling cascade can enhance cardiac function. We have previously shown that transgenic mice with cardiac overexpression of either the human beta2-adrenergic receptor (beta2AR) or an inhibitor of the beta-adrenergic receptor kinase (betaARK), an enzyme that phosphorylates and uncouples agonist-bound receptors, have increased myocardial inotropy. We now have created recombinant adenoviruses encoding either the beta2AR (Adeno-beta2AR) or a peptide betaARK inhibitor (consisting of the carboxyl terminus of betaARK1, Adeno-betaARKct) and tested their ability to potentiate beta-adrenergic signaling in cultured adult rabbit ventricular myocytes. As assessed by radioligand binding, Adeno-beta2AR infection led to approximately 20-fold overexpression of beta-adrenergic receptors. Protein immunoblots demonstrated the presence of the Adeno-betaARKct transgene. Both transgenes significantly increased isoproterenol-stimulated cAMP as compared to myocytes infected with an adenovirus encoding beta-galactosidase (Adeno-betaGal) but did not affect the sarcolemmal adenylyl cyclase response to Forskolin or NaF. beta-Adrenergic agonist-induced desensitization was significantly inhibited in Adeno-betaARKct-infected myocytes (16+/-2%) as compared to Adeno-betaGal-infected myocytes (37+/-1%, P < 0.001). We conclude that recombinant adenoviral gene transfer of the beta2AR or an inhibitor of betaARK-mediated desensitization can potentiate beta-adrenergic signaling.
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PMID:Potentiation of beta-adrenergic signaling by adenoviral-mediated gene transfer in adult rabbit ventricular myocytes. 900 97

Accumulation of intracellular cyclic adenosine monophosphate (cAMP) has been shown to inhibit the growth of cultured airway smooth-muscle cells, but the precise mechanism underlying the antimitogenic action of cAMP in these cells is unknown. We examined the effects of forskolin, an activator of adenylate cyclase, on DNA synthesis, cyclin D1 expression, and cAMP response element-binding protein (CREB) phosphorylation and DNA binding in bovine tracheal myocytes. DNA synthesis was assessed by measurement of [3H]thymidine incorporation. Cyclin D1 protein abundance and CREB phosphorylation were assessed by immunoblotting. Cyclin D1 promoter transcriptional activation was determined by measurement of luciferase activity in cells transiently cotransfected with complementary DNAs encoding the full-length cyclin D1 promoter subcloned into a luciferase reporter and beta-galactosidase (to normalize for transfection efficiency). The binding of nuclear proteins to the cyclin D1 promoter cAMP response element (CRE) was determined by electrophoretic mobility shift assay. We found that forskolin attenuated platelet-derived growth factor-induced DNA synthesis in a concentration-dependent manner. In addition, forskolin pretreatment decreased both cyclin D1 promoter activity and protein levels. Forskolin treatment induced the phosphorylation of CREB and increased the binding of nuclear protein to the cyclin D1 promoter CRE. Finally, addition of an antibody against CREB1 induced supershift of at least one protein-DNA complex. Together, these data suggest that cAMP suppresses cyclin D1 gene expression via phosphorylation and transactivation of CREB. Further studies are needed to determine whether this is the primary mechanism of cAMP-induced growth inhibition, or whether additional pathways are also involved.
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PMID:Forskolin inhibits cyclin D1 expression in cultured airway smooth-muscle cells. 992 28

We have employed a yeast (Saccharomyces cerevisiae) based rat androgen receptor expression system to examine the cross-talk between different signalling pathways. We report here the synergistic modulation of androgen regulated transcriptional activation of beta-galactosidase reporter activity by the activators of protein kinase-A, like forskolin and 8-bromo-cyclic AMP. A similar ligand-dependent enhancement of reporter activity compared to a DHT treated control has been noticed with okadaic acid, which is a potent inhibitor of protein phosphatase. The activation could be blocked by protein kinase-A/C inhibitor, H7. Forskolin treatment neither altered levels of receptor mRNA nor [3H]R1881 binding to the receptor. Although it promotes binding of receptor to an androgen response element, forskolin was unable to activate subsequent interaction with the transcription machinery in the absence of androgen. Additionally, the synergistic actions of these activators were independent of the degree of androgen response element occupancy. Anti-androgens, cyproterone acetate and flutamide, which failed to exhibit antagonistic behaviour with yeast expressed receptor, were able to antagonize only the forskolin mediated augmentation of reporter activity. Finally, analyses of mutants established the role of DNA and steroid binding domains of receptor for this synergism.
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PMID:Synergistic activation of yeast-expressed rat androgen receptor by modulators of protein kinase-A. 1002 42

The goal of this study was to enhance transgene expression after adenoviral-mediated gene transfer to the carotid artery. We used an adenoviral vector with a transgene that expresses beta-galactosidase, driven by the human cytomegalovirus (CMV) promoter/enhancer. The CMV promoter drives constitutive expression, and response elements within the enhancer allow inducible expression through binding of active transcription factors, such as cAMP response element binding protein (CREB) and nuclear factor kappa B (NFkappaB). Rings of rabbit carotid artery were incubated ex vivo with a replication-deficient adenovirus that expresses beta-galactosidase (AdCMV-betagal). Virus was removed from the medium, and forskolin or phorbol-12-myristate-13-acetate (PMA), which can induce activation of CREB or NFkappaB, respectively, were added to the medium. Pyrrolidine dithiocarbamate (PDTC) was used to inhibit activation of NFkappaB. Following incubation for 24 hours, beta-galactosidase activity was assessed by chemiluminescent reporter assay. Forskolin and PMA enhanced transgene expression in the carotid artery. Activity increased from 56+/-13 mU/mg protein (mean+/-SE) in rings of carotid treated with virus alone (10(9) pfu) to 159+/-23 mU/mg protein (P<0.05) in rings treated with forskolin, and to 189+/-40 mU/mg protein (P<0.05) in rings treated with PMA. Phorbol didecanoate, an inactive phorbol, did not affect expression of beta-galactosidase. After pre-incubation with PDTC prior to PMA, expression of beta-galactosidase was less than in rings incubated with PMA alone (29+/-11, P<0.05). Histochemical staining of carotid artery for beta-galactosidase demonstrated enhanced endothelial expression following administration of PMA. These findings suggest that expression after gene transfer to the carotid artery using an adenoviral vector with the CMV promoter/enhancer may be enhanced by PMA and forskolin, perhaps by activation of transcription factors.
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PMID:Approaches to enhance expression after adenovirus-mediated gene transfer to the carotid artery. 1059 61