Lysophosphatidic acid-induced arterial wall remodeling: Requirement of PPARγ but not LPA1 or LPA2 GPCR

Lysophosphatidic acid (LPA) and its ether analog alkyl-glycerophosphate (AGP) elicit arterial wall remodeling when applied intralumenally into the uninjured carotid artery. LPA is the ligand of eight GPCRs and the peroxisome proliferator-activated receptor γ (PPARγ). We pursued a gene knockout strategy to identify the LPA receptor subtypes necessary for the neointimal response in a non-injury model of carotid remodeling and also compared the effects of AGP and the PPARγ agonist rosiglitazone (ROSI) on balloon injury-elicited neointima development. In the balloon injury model AGP significantly increased neointima; however, rosiglitazone application attenuated it. AGP and ROSI were also applied intralumenally for 1 h without injury into the carotid arteries of LPA₁, LPA₂, LPA_1&2 double knockout, and Mx1Cre-inducible conditional PPARγ knockout mice targeted to vascular smooth muscle cells, macrophages, and endothelial cells. The neointima was quantified and also stained for CD31, CD68, CD11b, and α-smooth muscle actin markers. In LPA₁, LPA₂, LPA_1&2 GPCR knockout, Mx1Cre transgenic, PPARγ^fl/−, and uninduced Mx1Cre × PPARγ^fl/− mice AGP- and ROSI-elicited neointima was indistinguishable in its progression and cytological features from that of WT C57BL/6 mice. In PPARγ^−/− knockout mice, generated by activation of Mx1Cre-mediated recombination, AGP and ROSI failed to elicit neointima and vascular wall remodeling. Our findings point to a difference in the effects of AGP and ROSI between the balloon injury- and the non-injury chemically-induced neointima. The present data provide genetic evidence for the requirement of PPARγ in AGP- and ROSI-elicited neointimal thickening in the non-injury model and reveal that the overwhelming majority of the cells in the neointimal layer express α-smooth muscle actin.     

Determination and pharmacokinetic study of taxifolin in rabbit plasma by high-performance liquid chromatography

Taxifolin has been widely used in the treatment of cerebral infarction and sequelae, cerebral thrombus, coronary heart disease and angina pectoris. A reliable sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method with UV detection for the pharmacokinetic study of taxifolin in rabbit plasma after enzymatic hydrolysis was developed and validated for the first time. Taxifolin, with biochanin A as the internal standard, was extracted from plasma samples by liquid/liquid extraction after hydrolysis with β-glucuronidase and sulfatase. Chromatographic separation was conducted on a Luna C18 column (4.6 mm×150 mm, 5 μm particle size) and pre-column (2.0 mm, the same sorbent). Two-step linear gradient elution with acetonitrile and 0.03% water solution of trifluoroacetic acid as mobile phase at a flow rate of 1.0 ml/min was used. The UV detector is set at 290 nm. The elution time for taxifolin and biochanin A was approximately 7.9 and 18.3 min, respectively. The calibration curve of taxifolin was linear (r>0.9997) over the range of 0.03–5.0 μg/ml in rabbit plasma. The limit of detection (LOD) and limit of quantification (LOQ) for taxifolin were 0.03 and 0.11 μg/ml, respectively. The present method was successfully applied for the estimation of the pharmacokinetic parameters of taxifolin following intravenous and oral administration of lipid solution to rabbits. The absolute bioavailability of taxifolin after oral administration of lipid solution was 36%.     

Computational prediction of essential genes in an unculturable endosymbiotic bacterium, Wolbachia of Brugia malayi

Background  

Wolbachia (wBm) is an obligate endosymbiotic bacterium of Brugia malayi, a parasitic filarial nematode of humans and one of the causative agents of lymphatic filariasis. There is a pressing need for new drugs against filarial parasites, such as B. malayi. As wBm is required for B. malayi development and fertility, targeting wBm is a promising approach. However, the lifecycle of neither B. malayi nor wBm can be maintained in vitro. To facilitate selection of potential drug targets we computationally ranked the wBm genome based on confidence that a particular gene is essential for the survival of the bacterium.     

Antifungal and phytostimulating characteristics of <Emphasis Type="Italic">Bacillus subtilis</Emphasis> Ch-13 rhizospheric strain,producer of bioprepations

Bacillus subtilis Ch-13 industrial strain was shown to have a wide spectrum of antagonistic activities against different species of phytopathogenic fungi and bacteria. The B. subtilis Ch-13 strain produces lytic enzymes; cyanide and other antifungal metabolites; stimulates plant growth, producing phytohormones—auxin derivatives. This strain by 2.5 times reduced the quantity of tomato plants infected with phytopathogenic fungus Fusarium oxysporum during inoculation. Fungi abundance on roots with bacterial inoculation was 6.9 times less than in the absence of inoculation. The application of detected antifungal metabolites as biochemical markers for the strain enables to control the stability of physiologic and biochemical characteristics of the producer, and ensures a rapid quality assay of biopreparations with high performance liquid chromatography (HPLC).     

Endocytic receptor LRP together with tPA and PAI-1 coordinates Mac-1-dependent macrophage migration

Migration of activated macrophages is essential for resolution of acute inflammation and the initiation of adaptive immunity. Here, we show that efficient macrophage migration in inflammatory environment depends on Mac-1 recognition of a binary complex consisting of fibrin within the provisional matrix and the protease tPA (tissue-type plasminogen activator). Subsequent neutralization of tPA by its inhibitor PAI-1 enhances binding of the integrin-protease-inhibitor complex to the endocytic receptor LRP (lipoprotein receptor-related protein), triggering a switch from cell adhesion to cell detachment. Genetic inactivation of Mac-1, tPA, PAI-1 or LRP but not the protease uPA abrogates macrophage migration. The defective macrophage migration in PAI-1-deficient mice can be restored by wild-type but not by a mutant PAI-1 that does not interact with LRP. In vitro analysis shows that tPA promotes Mac-1-mediated adhesion, whereas PAI-1 and LRP facilitate its transition to cell retraction. Our results emphasize the importance of ordered transitions both temporally and spatially between individual steps of cell migration, and support a model where efficient migration of inflammatory macrophages depends on cooperation of three physiologically prominent systems (integrins, coagulation and fibrinolysis, and endocytosis).     

The HicAB cassette, a putative novel, RNA-targeting toxin-antitoxin system in archaea and bacteria

Toxin-antitoxin systems (TAS) are abundant, diverse, horizontally mobile gene modules that encode powerful resistance mechanisms in prokaryotes. We use the comparative-genomic approach to predict a new TAS that consists of a two-gene cassette encoding uncharacterized HicA and HicB proteins. Numerous bacterial and archaeal genomes encode from one to eight HicAB modules which appear to be highly prone to horizontal gene transfer. The HicB protein (COG1598/COG4226) has a partially degraded RNAse H fold, whereas HicA (COG1724) contains a double-stranded RNA-binding domain. The stable combination of these two domains suggests a link to RNA metabolism, possibly, via an RNA interference-type mechanism. In most HicB proteins, the RNAse H-like domain is fused to a DNA-binding domain, either of the ribbon-helix-helix or of the helix-turn-helix class; in other TAS, proteins containing these DNA-binding domains function as antitoxins. Thus, the HicAB module is predicted to be a novel TAS whose mechanism involves RNA-binding and, possibly, cleavage.     

Gamasid mites (Parasitiformes,Mesostigmata) in nests of passerine birds on the Arctic Seven Islands Archipelago,the Barents Sea

Examination of 31 nests of 6 common passerine bird species collected on the Seven Islands Archipelago (the Barents Sea) revealed 25 species of gamasid mites. Most of them belonged to the widespread free-living species commonly occurring in the neighboring taiga and southern tundra areas. There were practically no true Arctic forms among the gamasids found; by contrast, the local flora consisted almost by half of Arctic and Hypoarctic species. The findings of only one species, Neoseiulus cf. tobon, appear to be restricted to the Arctic, while the range of the rare parthenogenetic Iphidinychus gaieri may be restricted to Hypoarctic and mountainous regions of Eurasia. No bird parasites were recorded. Host specificity of the mite assemblages of the nests was not observed.     

Polymorphism of Xenobiotic Metabolism Genes in Petrochemical Workers

Genetic polymorphism of xenobiotic metabolizing enzymes responsible for individual susceptibility to different environmental factors was examined in a cohort of petrochemical workers occupationally exposed to adverse action of chemical compounds. Molecular genetic analysis of the I462V mutation in exon 7 of the CYP1A1gene demonstrated close similarity between the genotype and allele frequency distribution patterns in the industrial and control groups. No association between the CYP1A1polymorphic alleles and genotypes and the duration of service and concomitant diseases was observed. The odds ratio of the disease development in the workers carrying heterozygous CYP1A1 mutant allele was 2.2. Analysis of the GSTM1 gene polymorphism demonstrated a decrease in the frequency of the homozygous deletion carriers in the workers compared to the control group. There were no substantial differences between the industrial and control groups with respect to the frequencies of rapid and slow acetylator genotypes revealed at the analysis of the NAT2 gene polymorphism. However, considering the concomitant diseases, in the corresponding industrial subgroup a clear trend towards lower frequency of rapid acetylators was demonstrated. In addition, the odds ratio of the disease development for the workers with slow acetylator phenotype was 1.7.