Lansoprazole protects and heals gastric mucosa from non-steroidal anti-inflammatory drug (NSAID)-induced gastropathy by inhibiting mitochondrial as well as Fas-mediated death pathways with concurrent induction of mucosal cell renewal

We have investigated the mechanism of antiapoptotic and cell renewal effects of lansoprazole, a proton pump inhibitor, to protect and heal gastric mucosal injury in vivo induced by indomethacin, a non-steroidal anti-inflammatory drug (NSAID). Lansoprazole prevents indomethacin-induced gastric damage by blocking activation of mitochondrial and Fas pathways of apoptosis. Lansoprazole prevents indomethacin-induced up-regulation of proapoptotic Bax and Bak and down-regulation of antiapoptotic Bcl-2 and Bcl(xL) to maintain the normal proapoptotic/antiapoptotic ratio and thereby arrests indomethacin-induced mitochondrial translocation of Bax and collapse of mitochondrial membrane potential followed by cytochrome c release and caspase-9 activation. Lansoprazole also inhibits indomethacin-induced Fas-mediated mucosal cell death by down-regulating Fas or FasL expression and inhibiting caspase-8 activation. Lansoprazole favors mucosal cell renewal simultaneously by stimulating gene expression of prosurvival proliferating cell nuclear antigen, survivin, epidermal growth factor, and basic fibroblast growth factor. The up-regulation of Flt-1 further indicates that lansoprazole activates vascular epidermal growth factor-mediated controlled angiogenesis to repair gastric mucosa. Lansoprazole also stimulates the healing of already formed ulcers induced by indomethacin. Time course study of healing indicates that it switches off the mitochondrial death pathway completely but not the Fas pathway. However, lansoprazole heals mucosal lesions almost completely after overcoming the persisting Fas pathway, probably by favoring the prosurvival genes expression. This study thus provides the detailed mechanism of antiapoptotic and prosurvival effects of lansoprazole for offering gastroprotection against indomethacin-induced gastropathy.     

Surfactant-induced lipid peroxidation in a tropical euryhaline teleost Oreochromis mossambicus (Tilapia) adapted to fresh water

Exposure to anionic (sodium dodecyl sulfate, SDS), cationic (cetyl trimethyl ammonium bromide CTAB) and non ionic (Triton X-100) surfactants at a sub lethal concentration of 1 ppm resulted in severe oxidative stress in the hepatic, renal and cardiac tissues of fresh water adapted Oreochromis mossambicus. Hepatic catalase showed significant increase (P<0.001) in all the surfactant exposed fish, but the renal enzyme was significantly increased only in CTAB dosed fish (P<0.001) and the cardiac enzyme showed significant increase in Triton (P<0.05) and CTAB dosed fish (P<0.001). SOD levels were significantly increased (P<0.001) in hepatic, renal and cardiac tissues of all the surfactant-treated fish. Glutathione reductase also was significantly increased (P<0.001) in the hepatic and renal tissues of surfactant dosed fish except cardiac tissues of CTAB exposed animals. Glutathione levels in the tissues studied were significantly higher in the surfactant treated animals (P<0.001) whereas malondialdehyde levels were significantly elevated only in the hepatic tissues of animals exposed to Triton (P<0.001). The surfactants based on their charge, antioxidant profile and in vivo metabolism may be arranged in the order of decreasing toxicity as CTAB > Triton > SDS. Thus it may be inferred from the present study that the antioxidant defenses and the in vivo metabolism of the surfactants are key factors in deciding the surfactant toxicity.     

beta1 integrins expression in adult rat ventricular myocytes and its role in the regulation of beta-adrenergic receptor-stimulated apoptosis

We have shown that the stimulation of beta-adrenergic receptors (beta-AR) increases apoptosis in adult rat ventricular myocytes (ARVMs). Integrins, a family of alphabeta-heterodimeric cell surface receptors, are postulated to play a role in ventricular remodeling. Here, we show that norepinephrine (NE) increases beta1 integrins expression in ARVMs via the stimulation of alpha1-AR, not beta-AR. Inhibition of ERK1/2 using PD 98059, an inhibitor of ERK1/2 pathway, inhibited alpha1-AR-stimulated increases in beta1 integrins expression. Activation of beta1 integrins signaling pathway using laminin (LN) inhibited beta-AR-stimulated apoptosis as measured by terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL)-staining and flow cytometry. Likewise, ligation of beta1 integrins with anti-beta1 integrin antibodies prevented beta-AR-stimulated apoptosis. Treatment of cells using LN or anti-beta1 integrin antibodies activated ERK1/2 pathway. PD 98059 inhibited activation of ERK1/2 by LN, and prevented the anti-apoptotic effects of LN. Thus (1) stimulation of alpha1-AR regulates beta1 integrins expression via the activation of ERK1/2, (2) beta1 integrins signaling protects ARVMs from beta-AR-stimulated apoptosis, (3) activation of ERK1/2 plays a critical role in the anti-apoptotic effects of beta1-integrin signaling. These data suggest that beta1 integrin signaling protects ARVMs against beta-AR-stimulated apoptosis possibly via the involvement of ERK1/2.     

Relaxation of arterial smooth muscle by water-soluble derivatives of coenzyme Q (ubiquinone)

Treatment of coenzyme Q with ozone, permanganate, and ferrous sulfate in presence of ascorbate or hydrogen peroxide yielded water-soluble degradation products, possibly having truncated side-chain and modified ring.These derivatives, but not the intact lipid-quinone, showed relaxation of phenylephrine-contracted rat arterial rings. Representative samples of these also decreased blood pressure when injected into the femoral vein in the rat.These effects offer an explanation for the hypotensive action of exogenous coenzyme Q regardless of its side-chain length.     

Synthesis and SAR of 4-(3-hydroxyphenylamino)pyrrolo[2,1-f][1,2,4]triazine based VEGFR-2 kinase inhibitors

A versatile synthesis of the suitably functionalized pyrrolo[2,1-f][1,2,4]triazine nucleus is described. SAR at the C-5 and C-6 positions of the 4-(3-hydroxy-4-methylphenylamino)pyrrolo[2,1-f][1,2,4]triazine template led to compounds with good in vitro potency against VEGFR-2 kinase. Glucuronidation of the phenol group is mitigated by incorporation of a basic amino group on the C-6 side chain of the pyrrolotriazine nucleus.     

Synthesis of a C-terminally biotinylated macrocyclic peptide mimetic exhibiting high Grb2 SH2 domain-binding affinity

Although considerable effort has been devoted to developing Grb2 SH2 domain-binding antagonists, important questions related to ligand specificity, and identification of intracellular targets remain unanswered. In order to begin addressing these issues, the design, synthesis, and evaluation of a novel biotinylated macrocycle are reported that bears biotin functionality at a C-terminal rather than the traditional N-terminal position. With a Grb2 SH2 domain-binding K(eq) value of 3.4 nM, the title macrocycle (5) is among the most potent biotinylated SH2 domain-binding ligands yet disclosed. This should be a useful tool for elucidating physiological targets of certain Grb2 SH2 domain-binding antagonists.     

An inducible targeted tagging system for localized saturation mutagenesis in Arabidopsis

We describe a system of inducible insertional mutagenesis based on the Ac-Ds family of transposons for targeted tagging in Arabidopsis (Arabidopsis thaliana). In this system, the Ac and Ds elements are carried within the same T-DNA and a heat shock-inducible transposase fusion is utilized to control the levels of transposase gene expression, generating transpositions that can be subsequently stabilized without requiring crossing or segregation. We have mapped 40 single-copy lines by thermal asymmetric interlaced-PCR, which can be used as potential launch pads for heat shock mutagenesis. Using a starter line selected for detailed analysis, the efficiency of tagging over a 50-kb region in the genome was examined. Hits were obtained in the targeted genes with multiple alleles for most genes, with approximately equal numbers of hits detected in genes on either side of the T-DNA. These results establish the feasibility of our approach for localized saturation mutagenesis in Arabidopsis. This system is very efficient and much less laborious as compared to conventional crossing schemes and may be generally applicable to other plant species for which large-scale T-DNA tagging is not currently feasible.     

Virulence properties of uropathogenic <Emphasis Type="Italic">Escherichia coli</Emphasis> isolated from children with urinary tract infection in Korea

Urinary tract infections (UTIs) are one of the most common types of bacterial infection in humans in various parts of the world and are caused mainly by uropathogenic Escherichia coli (UPEC). A total of 58 UPEC isolates from urine were characterized by serotyping and pulsed-field gel electrophoresis (PFGE). The majority of the UPEC strains belonged to serogroups O2 and O6. The UPEC strains were grouped under different pulsotypes and majority of them belonged to serogroups O2 and O6. Among the 14 virulence factors considered, 13 were present in various serogroups. The virulence genes fimH and sfa were present in all the isolates while none of the isolates carried lt-1. The strains exhibited 36 different virulence patterns, of which 11, referred to as UP (UPEC pattern) 1 to UP 11 were most common. Antibiotic resistance profiling of the UPEC isolates revealed that the serogroups O2 and O6 contain the highest number of resistant strains. The data from the current study depicting the distribution of UPEC strains among various serogroups and pulsotypes, and the occurrence of virulence genes and antibiotics resistance offer useful information on the epidemiological features of UPEC in Korea for the enhanced surveillance of potential emergence of UPEC.