No description available.

No description available.

No description available.

In airway epithelia, lactoperoxidase (LPO) constitutes an important anti-microbial system to protect the host against infection and inflammation. LPO uses hydrogen peroxide and thiocyanate anion to form the biocidal compound, hypothiocyanite. The rate-limiting factor is hydrogen peroxide substrate availability. This study was conducted to identify the major source of hydrogen peroxide and to characterize its regulation in the human airway. Two homologues of the phagocytic NADPH oxidase, Duox1 and Duox2, were shown to be highly expressed and functional in human airway epithelial cells re-differentiated at the air liquid interface (ALI). Duox activity is regulated by intracellular calcium concentration via its two EF-hand motifs. A rise of intracellular calcium concentration exhibited kinetics that correlated with increase of Duox-generated hydrogen peroxide production, which was inhibited by DPI, a NADPH oxidase inhibitor. Additionally, the involvement of Duox activity in the LPO system was investigated. Bacterial products such as flagellin or inflammatory mediators were used to challenge ALI cultures. As a result, mRNAs from Duox2, LPO and DUOXA2, but not Duox1, were up-regulated in response to stimuli. This study provided new information about the regulation of the anti-microbial LPO system in innate immune host defense.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O lapachol, uma naftoquinona natural, e seus derivados sintÃticos tÃm demonstrado, nos Ãltimos anos, importantes aÃÃes citotÃxicas contra varias linhagens de cÃlulas tumorais, assim como significante atividade antitumoral contra alguns tumores. Assim, o objetivo desse trabalho foi avaliar o mecanismos de aÃÃo citotoxica em cÃlulas HL-60 de duas naftoquinonas sintÃticas anÃlogas do lapachol (compostos 1 e 2). Inicialmente foi investigado a atividade antiproliferativa dessas naftoquinonas apÃs um perÃodo de incubaÃÃo de 72h em cÃlulas leucÃmicas (HL-60) e cÃlulas mononucleadas do sangue perifÃrico (CMSP) onde foi observado que essas naftoquinonas mostraram-se ativas para estas linhagens com CI50 de 12 ÂM, 2,3 ÂM e 4,3 ÂM para o lapachol, composto 1 e composto 2, respectivamente em cÃlulas HL-60 e 13,7 ÂM e 34,0 ÂM para o composto 1 e 2 em cÃlulas CMSP, respectivamente. A atividade antiproliferativa em cÃlulas HL-60 apÃs 24 horas de incubaÃÃo foi avaliada com e sem co-tratamento com o antioxidante n-acetilcisteÃna (NAC). Assim, a CI50 sem NAC apÃs 24 horas de exposiÃÃo ao lapachol, composto 1 e composto 2 foi de 42,9 μM, 2,7 ÂM e 4,3 ÂM , respectivamente. JÃ CI50 com NAC (5 ÂM) apÃs 24 horas de exposiÃÃo ao lapachol, composto 1 e composto 2 foi de 180,0 μM, 46,0 ÂM e 18,0 ÂM , respectivamente. Estudos feitos em cÃlulas HL-60 indicaram que o lapachol e seus dois anÃlogos induzem morte celular por apoptose e necrose, como mostrado pelas mudanÃas morfolÃgicas avaliadas atravÃs do uso de coloraÃÃo May-GrÃnwald-Giemsa. Nos ensaios realisados por citometria de fluxo foi revelado que estes compostos promovem a geraÃÃo de espÃcies reativas de oxigÃnio (EROs) 18,86%, 13,31% e 39,11% respectivamente para o lapachol (82 ÂM) e compostos 1 e 2 (3,5 ÂM) e 40,94% e 60,49% para os compostos 1 e 2 (7,0 ÂM), respectivamente. O lapachol (82 ÂM) e os compostos 1 e 2 (3,5 ÂM) diminuÃram o nÃmero de cÃlulas com membrana Ãntegra 26,51%, 34,78% e 29,58% respectivamente e os compostos 1 e 2 (7,0 ÂM) diminuÃram 75,3% e 71,1%, respectivamente. A fragmentaÃÃo do DNA promovida por esses compostos foi observada a partir de 3 horas de exposiÃÃo sendo mais intensa apÃs 24 horas de exposiÃÃo aos compostos testados. O lapachol e os compostos 1 e 2 tambÃm promoveram a ativaÃÃo de caspases relacionadas com a via intrÃnseca de morte celular. AlÃm disso, mostraram induzir a quebra de fitas de DNA. Todos os efeitos citotÃxicos foram abolidos quando os compostos 1 e 2 foram co-incubados com o NAC, mostrando, dessa forma, a participaÃÃo de EROs na citotÃxicidade destas naftoquinonas. / The lapachol, one naphthoquinone natural, and its derivatives synthetic have demonstrated, in recent years, important actions cytotoxic against several lineages of tumor cells, well as signifier antitumoral activity against some tumors. Thus, the objective this work was to evaluate the mechanisms of action cytotoxic in cells HL-60 of two naphthoquinones synthetic analogous of lapachol (compounds 1 and 2). Initially was investigated at antiproliferative activity these naphthoquinones after a incubation period of 72 hours in leukemic cells (HL-60) and peripheral blood mononucleated cells (PBMC) where was observed that these naphthoquinones were active for these lines with IC50 of 12 ÂM , 2.3 ÂM and 4.3 ÂM for the lapachol, compound 1 and compound 2, respectively in cells HL-60 and 13.7 ÂM and 34.0 ÂM for compound 1 and 2 in cells PBMC, respectively. The antiproliferative activity in cells HL-60 after 24 hours incubation was evaluated with and without co-treatment with the antioxidant n-acetylcysteine (NAC). Thus, IC50 without NAC after 24 hours of exposure to lapachol, compound 1 and compound 2 was 42.9 ÂM, 2.7 ÂM and 4.3 ÂM, respectively. Have IC50 with NAC (5 ÂM) after 24 hours of exposure to lapachol, compound 1 and compound 2 was 180.0 ÂM, 46.0 ÂM and 18.0 ÂM, respectively. Studies done in HL-60 cells indicated that the lapachol and its two analogues induce cell death by apoptosis and necrosis, as shown by morphological changes evaluated through the use of staining May-GrÃnwald-Giemsa. In trials realisados by flow cytometry was revealed that these compounds promote the generation of reactive oxygen species (ROS) 18.86%, 13.31% and 39.11% respectively for the lapachol (82 ÂM) and compounds 1 and 2 (3,5 ÂM) and 40.94% and 60.49% for the compounds 1 and 2 (7.0 ÂM), respectively. The lapachol (82 ÂM) and the compounds 1 and 2 (3.5 ÂM) decreased the number of cells with intact membrane 26.51%, 34.78% and 29.58% respectively and the compounds 1 and 2 (7, 0 ÂM) decreased 75.3% and 71.1%, respectively. The DNA fragmentation promoted by such compounds was observed starting from 3 hours of exposure being more intense after 24 hours of exposure to tested compounds. The lapachol and the compounds 1 and 2 also promoted the activation of caspases related to intrinsic pathway of cell death. Furthermore, showed induce the synthesis of DNA strands. All cytotoxic effects were abolished when the compounds 1 and 2 were co-incubated with the NAC, showing thus the participation ROS in cytotoxicity these naphthoquinones.

Sepsis-related multiple organ dysfunction syndrome is a leading cause of death in intensive care units. There is overwhelming evidence that oxidative stress plays a significant role in the pathogenesis of sepsis-associated multiple organ failure; however, reactive oxygen species (ROS)-associated biomarkers and/or diagnostics that define mortality or predict survival in sepsis are lacking. Lung or peripheral blood gene expression analysis has gained increasing recognition as a potential prognostic and/or diagnostic tool. The objective of this study was to identify ROS-associated biomarkers predictive of survival in patients with sepsis. In-silico analyses of expression profiles allowed the identification of a 21-gene ROS-associated molecular signature that predicts survival in sepsis patients. Importantly, this signature performed well in a validation cohort consisting of sepsis patients aggregated from distinct patient populations recruited from different sites. Our signature outperforms randomly generated signatures of the same signature gene size. Our findings further validate the critical role of ROSs in the pathogenesis of sepsis and provide a novel gene signature that predicts survival in sepsis patients. These results also highlight the utility of peripheral blood molecular signatures as biomarkers for predicting mortality risk in patients with sepsis, which could facilitate the development of personalized therapies.

No description available.

Cassava ranks seventh in terms of worldwide crop production, providing a staple for over half a billion people. The production of cassava is limited by several factors, with post-harvest physiological deterioration (PPD) of storage roots a major constraint. PPD is a process initiated on harvesting and mediated by reactive oxygen species (ROS) that ultimately renders storage roots unpalatable and unmarketable. It is similar to a conventional plant wound response, but crucially lacks efficient wound repair and down-regulation of stress signalling. Therefore, the strategy utilised here to modulate PPD focussed on increasing the ROS scavenging ability of storage root tissue through a biotechnological approach. Three expression plasmids were produced, harbouring cassava genes encoding the antioxidant enzymes APX, CAT and SOD under the control of the storage rootspecific StPAT promoter. In addition, a reporter expression plasmid was created, with StPAT driving the expression of GusP. Transgenic Arabidopsis plants containing the StPAT::GusP cassette demonstrated root-specific GusP staining. Non-root tissue also showed wound-inducible GusP activity conferred by the StPAT promoter. This novel activity was detected almost immediately after wounding and occurred independently of ethylene, MeJa and ROS. The 3’ 261 bp of the StPAT promoter was sufficient to confer wound-inducible expression and contained putative wound responsive cis regulatory motifs. Analysis of PATATIN function indicated a role during early responses to wounding in the liberation of free fatty acids from cell membranes. Over-expression of the target genes in the model plant Arabidopsis increased the antioxidant enzyme activity in the roots of selected lines. Transgenic plants generally exhibited similar levels of oxidative stress resistance to wild-type plants, a result due in part to the efficient nature of the oxidative stress response of Arabidopsis – the APX activity of wild-type plants increased to transgenic levels under H2O2 stress. However, PPD in cassava is at least partially the result of a poor antioxidant response to harvesting, and so transformation of cassava with the expression plasmids remained a viable strategy. Transgenic cassava plants harbouring the expression cassettes are being generated and will soon be assessed for PPD resistance.

Artemisinin (AN), a sesquiterpene, derived from the herb, Artemisia annua is the most widely used anti-malarial compound. Current production is insufficient to meet the growing demand for this important drug. Many experiments have been done to try and deduce what factors may be important to increased yield. Here is is shown that many disparate phenomena known to induce AN production may be linked under the umbrella of reactive oxygen species (ROS). To that end, the metabolite and transcriptional changes associated with the transition from vegetative growth to flowering have been investigated. In addition, the role that exogenous sugars play in modulating these same factors has been explored in young seedlings. Lastly, exposure to DMSO was shown to increase AN production and that it may be linked to ROS. These combined results wered further explored to determine the effects of direct ROS elicitation and subsequent quenching on the production of AN and related metabolites. Information gained here supported a new alternative hypothesis for the role of ROS in AN production, one in which hydrogen peroxide may be controlling the balance of deoxyartemisinin (deoxyAN) and AN.

Philosophiae Doctor - PhD / Parkinson’s disease (PD) is a common neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta of the midbrain. Although the etiology of PD is not completely known, it is believed to involve an association of various genetic, cellular, and environmental factors that individually or simultaneously advance neuronal degeneration. Neurotoxins such as 1-methyl-4-phenylpyridinium (MPP+) and 6-hydroxydopamine (6-OHDA) have been widely used to investigate distinct underlying mechanisms involved in the pathogenesis of PD. Presently, treatment options for PD are limited, as the available drugs are mainly focused on alleviating symptoms with limited ability to prevent disease progression. Accordingly, there is an increase in the use of natural compounds/products as potential neuroprotective agents. These neuroprotective treatments are believed to intervene in some stages in the pathogenesis of PD to suppress possible mechanisms of dopaminergic neuronal death such as apoptosis, mitochondrial dysfunction, oxidative stress, disturbances of calcium homeostasis, inflammation and autophagy. Thus, novel protective strategies for PD may be designed by targeting these mechanisms or intracellular signaling cascades that participate in PD pathogenesis.