p14 Arf promotes small ubiquitin-like modifier conjugation of Werners helicase

Here we demonstrate a novel p53-independent interaction between the nucleolar tumor suppressors, p14 Arf and Werners helicase (WRN). Binding of p14 Arf to WRN is multivalent and resembles the binding of p14 Arf to Mdm2. Residues 2-14 and 82-101 of p14 Arf and residues in the central region and C terminus of WRN have particular importance for binding. p14 Arf promotes small ubiquitin-like modifier (SUMO) modification of WRN in a synergistic manner with the SUMO-conjugating enzyme, UBCH9. p14 Arf causes redistribution of WRN within the nucleus, and this effect is reversed by expression of a SUMO-specific protease, thus implicating the SUMO conjugation pathway in WRN re-localization. We establish that the ability to promote SUMO conjugation is a general property of the p14 Arf tumor suppressor.     

Interaction between complementary liposomes: a process leading to multicompartment systems formation

Interaction of complementary liposomes induces a series of processes, involving reorganization of their membrane lipids, which lead to the formation of large aggregates. In several cases these aggregates exhibit multicompartment structures and only primitively mimic, in some aspects at least, the multicompartmental features of cells. Similar multicompartment structures were repeatedly obtained following the interaction of a diversity of complementary liposomal pairs. Thus, a working hypothesis is proposed, according to which, molecular recognition of liposomes induces the formation of multicompartment structures.     

Synthesis, conformational characteristics and anti-influenza virus A activity of some 2-adamantylsubstituted azacycles

The broad-spectrum antiviral activity of 2-(2-adamantyl)piperidines 11, 13a,b, and 15, 3-(2-adamantyl)pyrrolidines 27, 21a-g and 2-(2-adamantylmethyl)piperidines 30, 32a-c, and 35a-d was examined. Several compounds in the new series were potent against influenza A H(3)N(2) virus. When 1-aminoethyl pharmacophore group of 2-rimantadine 4 (2-isomer of rimantadine) is included into a saturated nitrogen heterocycle, see compound 11, potency was retained. The diamine derivatives 21e-g and particularly 35a-c possessing three pharmocophoric groups, that is, the adamantyl and the two amine groups, exhibited high potency. The new compounds did not afford specific activity at non-toxic concentrations against any of the other viruses tested. According to NMR spectroscopy and molecular mechanics calculations it is striking that the parent structures 11 and 27 adopt a fixed trans conformation around C2-C2' bond. In the parent amines, which proved to be active compounds, the distance between nitrogen and adamantyl pharmacophoric groups was different; N-C2' distance is 3.7, 3.8 A for 27, 30 and 2.5 A for 11 suggesting that M2 receptor site can accommodate different in size and orientation lipophilic cages.     

Pulmonary microRNA profiling in a mouse model of ventilator-induced lung injury

The aim of this study was to investigate the changes induced by high tidal volume ventilation (HVTV) in pulmonary expression of micro-RNAs (miRNAs) and identify potential target genes and corresponding miRNA-gene networks. Using a real-time RT-PCR-based array in RNA samples from lungs of mice subjected to HVTV for 1 or 4 h and control mice, we identified 65 miRNAs whose expression changed more than twofold upon HVTV. An inflammatory and a TGF-β-signaling miRNA-gene network were identified by in silico pathway analysis being at highest statistical significance (P = 10(-43) and P = 10(-28), respectively). In the inflammatory network, IL-6 and SOCS-1, regulated by miRNAs let-7 and miR-155, respectively, appeared as central nodes. In TGF-β-signaling network, SMAD-4, regulated by miR-146, appeared as a central node. The contribution of miRNAs to the development of lung injury was evaluated in mice subjected to HVTV treated with a precursor or antagonist of miR-21, a miRNA highly upregulated by HVTV. Lung compliance was preserved only in mice treated with anti-miR-21 but not in mice treated with pre-miR-21 or negative-control miRNA. Both alveolar-arterial oxygen difference and protein levels in bronchoalveolar lavage were lower in mice treated with anti-miR-21 than in mice treated with pre-miR-21 or negative-control miRNA (D(A-a): 66 ± 27 vs. 131 ± 22, 144 ± 10 mmHg, respectively, P < 0.001; protein concentration: 1.1 ± 0.2 vs. 2.3 ± 1, 2.1 ± 0.4 mg/ml, respectively, P < 0.01). Our results show that HVTV induces changes in miRNA expression in mouse lungs. Modulation of miRNA expression can affect the development of HVTV-induced lung injury.     

Differential expression of two small Hsps during diapause in the corn stalk borer Sesamia nonagrioides (Lef.)

We isolated and characterized two members of the α-crystallin/sHsp family, SnoHsp19.5 and SnoHsp20.8 from Sesamia nonagrioides (Lepidoptera: Noctuidae). The cDNAs encoded proteins of 174 and 185 amino acids, with calculated molecular weights of 19.5 and 20.8 kDa, respectively. The deduced amino acid sequences of SnoHsp19.5 and SnoHsp20.8 showed highest homology to Hsp19.7 of Mamestra brassicae and to Bombyx mori Hsp20.4, respectively. Expression patterns of SnoHsp19.5 and SnoHsp20.8 in non-diapausing individuals under different environmental conditions (heat or cold) showed different accumulation profiles for the two genes after heat and cold treatment. SnoHsp19.5 was consistently expressed, while SnoHsp20.8 gene was down-regulated in deep diapause and was up-regulated at the termination of diapause. Our results suggest that these two genes play distinctive roles in the regulation of diapause.     

D2-receptor-linked signaling pathways regulate the expression of hepatic CYP2E1

This study investigated the role of catecholamine-related signaling pathways in the regulation of hepatic cytochrome P450 (CYP2E1). Central and peripheral catecholamine depletion with reserpine down-regulated CYP2E1. On the other hand, selective peripheral catecholamine depletion with guanethidine increased CYP2E1 apoprotein levels. Enrichment of peripheral catecholamines with adrenaline suppressed p-nitrophenol hydroxylase activity (PNP). PNP activity was also markedly suppressed by l-DOPA. Stimulation of D(2)-receptors with bromocriptine up-regulated CYP2E1, as assessed by enzyme activity and protein levels, whereas blockade of D(2)-dopaminergic receptors with sulpiride down-regulated this isozyme. These findings indicate that central and peripheral catecholamines have different effects on CYP2E1. Central catecholamines appear related to the up-regulation, whereas the role of peripheral catecholamines is clearly related to the type and location of adrenoceptors involved. D(2)-receptor-linked signaling pathways have an up-regulating effect on CYP2E1, while D(1)-receptor pathways may down-regulate this isozyme. It is worth noting that the widespread environmental pollutant benzo(alpha)pyrene (B(alpha)P) altered the modulating effect of catecholaminergic systems on CYP2E1 regulation. In particular, whereas stimulation or blockade of adrenoceptors had no effect on constitutive PNP activity, exposure to B(alpha)P modified the impact of central and peripheral catecholamines and alpha(2)-adrenoceptors on CYP2E1 expression. It appears that under the influence of B(alpha)P, alpha(2)-adrenergic receptor-linked signaling pathways increased CYP2E1 apoprotein levels. Given that a wide range of xenobiotics and clinically used drugs are activated by CYP2E1 to toxic metabolites, including the production of reactive oxygen species (ROS), it is possible that therapies challenging dopaminergic receptor- and/or alpha(2)-adrenoceptor-linked signaling pathways may alter the expression of CYP2E1, thus affecting the progress and development of several pathologies.     

HP1-β is required for development of the cerebral neocortex and neuromuscular junctions

HP1 proteins are thought to be modulators of chromatin organization in all mammals, yet their exact physiological function remains unknown. In a first attempt to elucidate the function of these proteins in vivo, we disrupted the murine Cbx1 gene, which encodes the HP1-β isotype, and show that the Cbx1^−/−-null mutation leads to perinatal lethality. The newborn mice succumbed to acute respiratory failure, whose likely cause is the defective development of neuromuscular junctions within the endplate of the diaphragm. We also observe aberrant cerebral cortex development in Cbx1^−/− mutant brains, which have reduced proliferation of neuronal precursors, widespread cell death, and edema. In vitro cultures of neurospheres from Cbx1^−/− mutant brains reveal a dramatic genomic instability. Our results demonstrate that HP1 proteins are not functionally redundant and that they are likely to regulate lineage-specific changes in heterochromatin organization.