Prostaglandin E(2) protects human lung fibroblasts from cigarette smoke extract-induced apoptosis via EP(2) receptor activation

Prostaglandin E(2) (PGE(2)) has been shown to have a strong cytoprotective effect, inhibiting apoptosis. In the present study, we evaluated whether PGE(2) has a protective effect on cigarette smoke extract (CSE)-induced apoptosis in human lung fibroblasts. Apoptosis was assessed by various methods, including DNA content analysis. CSE (15%-20%) led to apoptosis and induced imbalance in favor of pro- over anti-apoptotic protein expression and activated caspases. PGE(2) blocked CSE-induced apoptosis and modulated the balance of pro- and anti-apoptotic proteins and decreased the activation of caspases. This anti-apoptotic effect was mediated via EP(2) receptor activation as the EP(2) agonist butaprost mimicked PGE(2) activity and siRNA for the EP(2) receptor blocked it. An adenylyl cyclase inhibitor was found to abolish the PGE(2)-mediated cytoprotective effect. Correspondingly, c-AMP analogs blocked CSE-induced apoptosis. Consistently, the protein kinase A (PKA) inhibitor KT-5720 abolished PGE(2)-mediated protection. PGE(2) and butaprost phosphorylated Bad and KT-5720 blocked phosphorylation. These results suggest that PGE(2) inhibits CSE-induced apoptosis via EP(2) receptor activation and activation of PKA, which leads to an alteration in the balance between pro- and anti-apoptotic factors. Through such a mechanism, PGE(2) may alter survival of cells in the smoke-exposed lungs, thus affecting the pathogenesis of cigarette smoke-induced disease.     

Possibility of Production of Amino Acids by Impact Reaction Using a Light-Gas Gun as a Simulation of Asteroid Impacts

In order to investigate impact production of carbonaceous products by asteroids on Titan and other satellites and planets, simulation experiments were carried out using a 2-stage light gas gun. A small polycarbonate or metal bullet with about 6.5 km/s was injected into a pressurized target chamber filled with 1 atm of nitrogen gas, to collide with a ice + iron target or an iron target or a ice + hexane + iron target. After the impact, black soot including fine particles was deposited on the chamber wall. The soot was carefully collected and analyzed by High Performance Liquid Chromatography (HPLC), Fourier Transform Infrared Spectroscopy (FT-IR), and Laser Desorption Time-of-Flight Mass Spectrometry (LD-ToF-MS). As a result of the HPLC analysis, about 0.04–8 pmol of glycine, and a lesser amount of alanine were found in the samples when the ice + hexane + iron target was used. In case of the ice + iron target and the iron target, less amino acids were produced. The identification of the amino acids was also supported by FTIR and LD-ToF-MS analysis.     

Asef controls vascular endothelial permeability and barrier recovery in the lung

Increased levels of hepatocyte growth factor (HGF) in injured lungs may reflect a compensatory response to diminish acute lung injury (ALI). HGF-induced activation of Rac1 GTPase stimulates endothelial barrier protective mechanisms. This study tested the involvement of Rac-specific guanine nucleotide exchange factor Asef in HGF-induced endothelial cell (EC) cytoskeletal dynamics and barrier protection in vitro and in a two-hit model of ALI. HGF induced membrane translocation of Asef and stimulated Asef Rac1-specific nucleotide exchange activity. Expression of constitutively activated Asef mutant mimicked HGF-induced peripheral actin cytoskeleton enhancement. In contrast, siRNA-induced Asef knockdown or expression of dominant-negative Asef attenuated HGF-induced Rac1 activation evaluated by Rac-GTP pull down and FRET assay with Rac1 biosensor. Molecular inhibition of Asef attenuated HGF-induced peripheral accumulation of cortactin, formation of lamellipodia-like structures, and enhancement of VE-cadherin adherens junctions and compromised HGF-protective effect against thrombin-induced RhoA GTPase activation, Rho-dependent cytoskeleton remodeling, and EC permeability. Intravenous HGF injection attenuated lung inflammation and vascular leak in the two-hit model of ALI induced by excessive mechanical ventilation and thrombin signaling peptide TRAP6. This effect was lost in Asef^−/− mice. This study shows for the first time the role of Asef in HGF-mediated protection against endothelial hyperpermeability and lung injury.     

Die Resorption des Ammonium- und Nitratstickstoffs durch Aspergillus oryzae

Ohne Zusammenfassung     

Abolished interaction of NUB1 with mutant AIPL1 involved in Leber congenital amaurosis

Constructs based on the pSUPER vector [Science 296 (2002) 550] and encoding small interfering RNAs specific for the Type I, Type II, or Type III isozymes of mammalian (rat) hexokinase were prepared. Transfection of Chinese hamster ovary and HeLa cells with these vectors resulted in selective depletion of the respective isozymes. A Zeocin marker was incorporated into the modified pSUPER vector, permitting isolation of stably transfected cell lines selectively depleted of the respective isozyme.     

Double PHD Fingers Protein DPF2 Recognizes Acetylated Histones and Suppresses the Function of Estrogen-related Receptor α through Histone Deacetylase 1

Estrogen-related receptor α (ERRα) is a member of the nuclear receptor superfamily and regulates many physiological functions, including mitochondrial biogenesis and lipid metabolism. ERRα enhances the transactivation function without endogenous ligand by associating with coactivators such as peroxisome proliferator-activated receptor γ coactivator 1 α and β (PGC-1α and -β) and members of the steroid receptor coactivator family. However, the molecular mechanism by which the transactivation function of ERRα is converted from a repressive state to an active state is poorly understood. Here we used biochemical purification techniques to identify ERRα-associated proteins in HeLa cells stably expressing ERRα. Interestingly, we found that double PHD fingers protein DPF2/BAF45d suppressed PGC-1α-dependent transactivation of ERRα by recognizing acetylated histone H3 and associating with HDAC1. DPF2 directly bound to ERRα and suppressed the transactivation function of nuclear receptors such as androgen receptor. DPF2 was recruited to ERR target gene promoters in myoblast cells, and knockdown of DPF2 derepressed the level of mRNA expressed by target genes of ERRα. These results show that DPF2 acts as a nuclear receptor-selective co-repressor for ERRα by associating with both acetylated histone H3 and HDAC1.