The C242T polymorphism of the p22-phox gene (CYBA) is associated with higher left ventricular mass in Brazilian hypertensive patients

<p>Abstract</p> <p>Background</p> <p>Reactive oxygen species have been implicated in the physiopathogenesis of hypertensive end-organ damage. This study investigated the impact of the C242T polymorphism of the p22-phox gene (CYBA) on left ventricular structure in Brazilian hypertensive subjects.</p> <p>Methods</p> <p>We cross-sectionally evaluated 561 patients from 2 independent centers [Campinas (n = 441) and Vitória (n = 120)] by clinical history, physical examination, anthropometry, analysis of metabolic and echocardiography parameters as well as p22-phox C242T polymorphism genotyping. In addition, NADPH-oxidase activity was quantified in peripheral mononuclear cells from a subgroup of Campinas sample.</p> <p>Results</p> <p>Genotype frequencies in both samples were consistent with the Hardy- Weinberg equilibrium. Subjects with the T allele presented higher left ventricular mass/height^2.7than those carrying the CC genotype in Campinas (76.8 ± 1.6 vs 70.9 ± 1.4 g/m^2.7; p = 0.009), and in Vitória (45.6 ± 1.9 vs 39.9 ± 1.4 g/m^2.7; p = 0.023) samples. These results were confirmed by stepwise regression analyses adjusted for age, gender, blood pressure, metabolic variables and use of anti-hypertensive medications. In addition, increased NADPH-oxidase activity was detected in peripheral mononuclear cells from T allele carriers compared with CC genotype carriers (p = 0.03).</p> <p>Conclusions</p> <p>The T allele of the p22-phox C242T polymorphism is associated with higher left ventricular mass/height^2.7and increased NADPH-oxidase activity in Brazilian hypertensive patients. These data suggest that genetic variation within NADPH-oxidase components may modulate left ventricular remodeling in subjects with systemic hypertension.</p

Antibacterial activity of Artemisia nilagirica leaf extracts against clinical and phytopathogenic bacteria

<p>Abstract</p> <p>Background</p> <p>The six organic solvent extracts of <it>Artemisia nilagirica </it>were screened for the potential antimicrobial activity against phytopathogens and clinically important standard reference bacterial strains.</p> <p>Methods</p> <p>The agar disk diffusion method was used to study the antibacterial activity of <it>A. nilagirica </it>extracts against 15 bacterial strains. The Minimum Inhibitory Concentration (MIC) of the plant extracts were tested using two fold agar dilution method at concentrations ranging from 32 to 512 μg/ml. The phytochemical screening of extracts was carried out for major phytochemical derivatives in <it>A. nilagirica</it>.</p> <p>Results</p> <p>All the extracts showed inhibitory activity for gram-positive and gram-negative bacteria except for <it>Klebsiella pneumoniae, Enterococcus faecalis </it>and <it>Staphylococcus aureus</it>. The hexane extract was found to be effective against all phytopathogens with low MIC of 32 μg/ml and the methanol extract exhibited a higher inhibition activity against <it>Escherichia coli, Yersinia enterocolitica, Salmonella typhi</it>, <it>Enterobacter aerogenes</it>, <it>Proteus vulgaris</it>, <it>Pseudomonas aeruginosa </it>(32 μg/ml), <it>Bacillus subtilis </it>(64 μg/ml) and <it>Shigella flaxneri </it>(128 μg/ml). The phytochemical screening of extracts answered for the major derivative of alkaloids, amino acids, flavonoids, phenol, quinines, tannins and terpenoids.</p> <p>Conclusion</p> <p>All the extracts showed antibacterial activity against the tested strains. Of all, methanol and hexane extracts showed high inhibition against clinical and phytopathogens, respectively. The results also indicate the presence of major phytochemical derivatives in the <it>A. nilagirica </it>extracts. Hence, the isolation and purification of therapeutic potential compounds from <it>A. nilagirica </it>could be used as an effective source against bacterial diseases in human and plants.</p

Expression of NADPH Oxidase (NOX) 5 in Rabbit Corneal Stromal Cells

To determine whether NOX 5 is expressed in rabbit corneal stromal cells (RCSC). NADPH oxidases (NOXes) are enzymes that preferentially use NADPH as a substrate and generate superoxide. Several isoforms of NOXes function as multi-protein complexes while NOX5 and DUOXs do not require the accessory proteins for their activity and possess calcium binding EF hands.Human NOX5 primers were used to amplify the rabbit NOX5 by RT-PCR. Amplified product was sequenced to confirm its identity. The protein encoded by the NOX5 was identified by western blot analysis. NOX5 siRNA was used to reduce transcript, protein, and calcium stimulated activity. In silico analyses were performed to establish the putative structure, functions, and evolution of rabbit NOX5.NOX activity was measured in RCSC with NADPH rather than NADH as a substrate. RT-PCR with NOX5 primers amplified 288 bp product using RCSC cDNA, which, when sequenced, confirmed its identity to human NOX5 mRNA. This sequence was used to predict the rabbit (Oryctolagus cuniculus) NOX5 gene. NOX5 siRNA reduced amounts of NOX5 mRNA in RCSC and reduced ionomycin stimulated superoxide production. A protein of about 65 to 70 kDa encoded by the NOX5 was detected by western blot analysis. In silico analysis predicted a putative rabbit NOX5 protein containing 801 amino acids. Motif searches predicted the presence of at least 3 putative EF-hands in N-terminus and a NOX domain in C terminal region.The data document that the NOX5 gene was expressed in cells of lagomorphs unlike rodents, making the rabbit an interesting model to study NOX5 functions. The activity of the rabbit NOX5 was calcium stimulated, a trait of NOX5 in general. NOX5 may also prove to be a useful genetic marker for studying the taxonomic position of lagomorphs and the Glires classification

Hypoxia-inducible Factor-1 Activation in Nonhypoxic Conditions: The Essential Role of Mitochondrial-derived Reactive Oxygen Species

Hypoxia-inducible factor-1 (HIF-1) is a key transcription factor for responses to low oxygen. Here we report that the generation of mitochondrial reactive oxygen species are essential for regulating HIF-1 in normal oxygen conditions in the vasculature

DNA damage induces reactive oxygen species generation through the H2AX-Nox1/Rac1 pathway

The DNA damage response (DDR) cascade and ROS (reactive oxygen species) signaling are both involved in the induction of cell death after DNA damage, but a mechanistic link between these two pathways has not been clearly elucidated. This study demonstrates that ROS induction after treatment of cells with neocarzinostatin (NCS), an ionizing radiation mimetic, is at least partly mediated by increasing histone H2AX. Increased levels of ROS and cell death induced by H2AX overexpression alone or DNA damage leading to H2AX accumulation are reduced by treating cells with the antioxidant N-Acetyl-L-Cysteine (NAC), the NADP(H) oxidase (Nox) inhibitor DPI, expression of Rac1N17, and knockdown of Nox1, but not Nox4, indicating that induction of ROS by H2AX is mediated through Nox1 and Rac1 GTPase. H2AX increases Nox1 activity partly by reducing the interaction between a Nox1 activator NOXA1 and its inhibitor 14-3-3zeta. These results point to a novel role of histone H2AX that regulates Nox1-mediated ROS generation after DNA damage

The NOX toolbox: validating the role of NADPH oxidases in physiology and disease

Reactive oxygen species (ROS) are cellular signals but also disease triggers; their relative excess (oxidative stress) or shortage (reductive stress) compared to reducing equivalents are potentially deleterious. This may explain why antioxidants fail to combat diseases that correlate with oxidative stress. Instead, targeting of disease-relevant enzymatic ROS sources that leaves physiological ROS signaling unaffected may be more beneficial. NADPH oxidases are the only known enzyme family with the sole function to produce ROS. Of the catalytic NADPH oxidase subunits (NOX), NOX4 is the most widely distributed isoform. We provide here a critical review of the currently available experimental tools to assess the role of NOX and especially NOX4, i.e. knock-out mice, siRNAs, antibodies, and pharmacological inhibitors. We then focus on the characterization of the small molecule NADPH oxidase inhibitor, VAS2870, in vitro and in vivo, its specificity, selectivity, and possible mechanism of action. Finally, we discuss the validation of NOX4 as a potential therapeutic target for indications including stroke, heart failure, and fibrosis