Inhibition of Poly(ADP-ribose)polymerase impairs Epstein Barr Virus lytic cycle progression

<p>Abstract</p> <p>Background</p> <p>Poly(ADP-ribosylation) is a post-translational modification of nuclear proteins involved in several cellular events as well as in processes that characterize the infective cycle of some viruses. In the present study, we investigated the role of poly(ADP-ribosylation) on Epstein-Barr Virus (EBV) lytic cycle activation.</p> <p>Results</p> <p>Inhibition of PARP-1 by 3-aminobenzamide (3-ABA) during EBV induction, diminished cell damage and apoptosis in the non-productive Raji cell line while markedly reducing the release of viral particles in the productive Jijoye cells. Furthermore, incubation with 3-ABA up-regulated the levels of LMP1 and EBNA2 latent viral proteins. At the same time, it slightly affected the expression of the immediate early BZLF1 gene, but largely down-regulated the levels of the early BFRF1 protein. The modulation of the expression of both latent and lytic EBV genes appeared to be post-transcriptionally regulated.</p> <p>Conclusion</p> <p>Taken together the data indicate that PARP-1 plays a role in the progression of EBV lytic cycle and therefore, PARP inhibitors might represent suitable pharmacological adjuncts to control viral spread in EBV productive infection.</p

Homeodomain Interacting Protein Kinase 2 Activation Compromises Endothelial Cell Response to Laminar Flow: Protective Role of p21waf1,cip1,sdi1

BACKGROUND: In the cardiovascular system, laminar shear stress (SS) is one of the most important source of endothelial protecting signals. Physical and chemical agents, however, including ionising radiations and anticancer drugs, may injure endothelial cells determining an increase in oxidative stress and genotoxic damage. Whether the SS protective function remains intact in the presence of strong oxidants or DNA damage is currently unclear. METHODS AND RESULTS: To investigate this aspect a series of experiments were performed in which HUVEC were exposed to sub-lethal doses of the radio-mimetic compound Bleomycin (Bleo; 10 microg/ml) which generated free radicals (ROS) without significantly compromising cell survival. Remarkably, the application of a SS of 12 dyne/cm(2) did not protect endothelial cells but markedly accelerated apoptosis compared to controls kept in static culture and in the presence of Bleo. Experiments with the inducible nitric oxide synthase (iNOS) inhibitor GW274150 significantly reduced the SS-dependent apoptosis indicating that the production of NO was relevant for this effect. At molecular level, the ataxia-telangectasia-mutated (ATM) kinase, the homeodomain-interacting protein kinase-2 (HIPK2) and p53 were found activated along a pro-apoptotic signalling pathway while p21(waf1,cip1,sdi1) was prevented from its protective action. RNA interference experiments revealed that HIPK2 and p53 were both important for this process, however, only the forced expression p21(waf1,cip1,sdi1) fully restored the SS-dependent pro-survival function. CONCLUSIONS: This study provides the first evidence that, in the presence of genotoxic damage, laminar flow contributes to endothelial toxicity and death and identifies molecular targets potentially relevant in endothelial dysfunction and cardiovascular disease pathogenesis

P300/CBP Associated Factor Regulates Nitroglycerin-Dependent Arterial Relaxation by N -Lysine Acetylation of Contractile Proteins

Objective—To address the role of epigenetic enzymes in the process of arterial vasorelaxation and nitrate tolerance, in vitro and in vivo experiments were performed in the presence or absence of glycerin trinitrate (GTN) and histone deacetylases/histone acetylases modulators. Methods and Results—In vitro single GTN administration rapidly increased cGMP synthesis and protein Nε-lysine acetylation in rat smooth muscle cells, including myosin light chain and smooth muscle actin. This phenomenon determined a decrease in myosin light chain phosphorylation and actomyosin formation. These effects were abolished by prolonged exposure to GTN and rescued by treatment with trichostatin A. In vivo, adult male rats were treated for 72 hours with subcutaneous injections of GTN alone or in combination with the histone deacetylases inhibitors Trichostatin A, suberoylanilide hydroxamic acid, MS-27–275, or valproic acid. Ex vivo experiments performed on aortic rings showed that the effect of tolerance was reversed by all proacetylation drugs, including the p300/CBP–associated factor activator pentadecylidenemalonate 1b (SPV106). Any response to GTN was abolished by anacardic acid, a potent histone acetylases inhibitor. Conclusion—This study establishes the following points: (1) GTN treatment increases histone acetylases activity; (2) GTN–activated p300/CBP associated factor increases protein Nε-lysine acetylation; (3) Nε-lysine acetylation of contractile proteins influences GTN–dependent vascular response. Hence, combination of epigenetic drugs and nitroglycerin may be envisaged as a novel treatment strategy for coronary artery disease symptoms and other cardiovascular accidents of ischemic origin

Inhibition of Poly(ADP-ribose)polymerase impairs Epstein Barr Virus lytic cycle progression-1

<p><b>Copyright information:</b></p><p>Taken from "Inhibition of Poly(ADP-ribose)polymerase impairs Epstein Barr Virus lytic cycle progression"</p><p>http://www.infectagentscancer.com/content/2/1/18</p><p>Infectious Agents and Cancer 2007;2():18-18.</p><p>Published online 11 Oct 2007</p><p>PMCID:PMC2170434.</p><p></p>cated times, cells were collected and subjected to Annexin V-FITC/PI staining as reported in the Methods. The upper part of the figure shows the dot blots of PI vs. Annexin V stain. All parameters and region settings were kept identical throughout all measurements. The table illustrates the percentages of necrotic cells (PI); secondary necrotic cells (PI/A); viable cells (V); Annexin V-positive (apoptotic) cells (A)