Lipoxygenases and Poly(ADP-Ribose) Polymerase in Amyloid Beta Cytotoxicity

The 12/15-lipoxygenase(s) (LOX), poly(ADP-ribose) polymerase (PARP-1) activity and mitochondrial apoptosis inducing factor (AIF) protein in the amyloid β (Aβ) toxicity were investigated in PC12 cells that express either wild-type (APPwt) or double Swedish mutation (APPsw) forms of human Aβ precursor protein. Different levels of Aβ secretion and free radicals formation characterize these cells. The results demonstrated a relationship between the Aβ levels and LOX protein expression and activity. High Aβ concentration in APPsw cells correlated with a significant increase in free radicals and LOX activation, which leads to translocation of p65/NF-κB into the nucleus. An increase in AIF expression in mitochondria was observed concurrently with inhibition of PARP-1 activity in the nuclear fraction of APPsw cells. We suggested that AIF accumulation in mitochondria may be involved in adaptive/protective processes. However, inhibition of PARP-1 may be responsible for the disturbances in transcription and DNA repair as well as the degeneration of APP cells. Under conditions of increased nitrosative stress, evoked by the nitric oxide donor, sodium nitroprusside (SNP, 0.5 mM), 70–80% of all cells types died after 24 h, significantly more in APPsw cells. There was no further significant change in mitochondrial AIF level and PARP-1 activity compared to corresponding non-treated cells. Only one exception was observed in PC12 control, where SNP significantly inhibits PARP-1 activity. Moreover, SNP significantly activated gene expression for 12/15-LOX in all types of investigated cells. Inhibitors of all LOX isoforms and specific inhibitor of 12-LOX enhanced the survival of cells that were subjected to SNP. We conclude that the LOX pathways may play a role in Aβ toxicity and in nitrosative-stress-induced cell death and that inhibition of these pathways offers novel protective strategies

HNO Binding in a Heme Protein: Structures, Spectroscopic Properties, and Stabilities

HNO can interact with numerous heme proteins, but atomic level structures are largely unknown. In this work, various structural models for the first stable HNO heme protein complex, MbHNO (Mb, myoglobin), were examined by quantum chemical calculations. This investigation led to the discovery of two novel structural models that can excellently reproduce numerous experimental spectroscopic properties. They are also the first atomic level structures that can account for the experimentally observed high stabilities. These two models involve two distal His conformations as reported previously for MbCNR and MbNO. However, a unique dual hydrogen bonding feature of the HNO binding was not reported before in heme protein complexes with other small molecules such as CO, NO, and O2. These results shall facilitate investigations of HNO bindings in other heme proteins

Using Shifts in Amino Acid Frequency and Substitution Rate to Identify Latent Structural Characters in Base-Excision Repair Enzymes

Protein evolution includes the birth and death of structural motifs. For example, a zinc finger or a salt bridge may be present in some, but not all, members of a protein family. We propose that such transitions are manifest in sequence phylogenies as concerted shifts in substitution rates of amino acids that are neighbors in a representative structure. First, we identified rate shifts in a quartet from the Fpg/Nei family of base excision repair enzymes using a method developed by Xun Gu and coworkers. We found the shifts to be spatially correlated, more precisely, associated with a flexible loop involved in bacterial Fpg substrate specificity. Consistent with our result, sequences and structures provide convincing evidence that this loop plays a very different role in other family members. Second, then, we developed a method for identifying latent protein structural characters (LSC) given a set of homologous sequences based on Gu's method and proximity in a high-resolution structure. Third, we identified LSC and assigned states of LSC to clades within the Fpg/Nei family of base excision repair enzymes. We describe seven LSC; an accompanying Proteopedia page (http://proteopedia.org/wiki/index.php/Fpg_Nei_Protein_Family) describes these in greater detail and facilitates 3D viewing. The LSC we found provided a surprisingly complete picture of the interaction of the protein with the DNA capturing familiar examples, such as a Zn finger, as well as more subtle interactions. Their preponderance is consistent with an important role as phylogenetic characters. Phylogenetic inference based on LSC provided convincing evidence of independent losses of Zn fingers. Structural motifs may serve as important phylogenetic characters and modeling transitions involving structural motifs may provide a much deeper understanding of protein evolution

Junius’ Struggle for Electoral Rights to Be Observed: Letter XI to His Grace the Duke of Grafton

This is translated letter by a well-known publicist who wrote in Britain in the late 1760s – early 1770s under the name of Junius. Junius’ letters have become classics of political journalism today. This letter is addressed to His Majesty’s Prime Minister, the Duke of Grafton, who authorized the expulsion of the legitimately elected representative from Middlesex, radical and controversial publicist J. Wilkes from the lower house of the British Parliament. Junius, who has no sympathy to the last one, shows the weakness and shortsightedness of the government, and, above all, the illegality of its actions.Работа представляет собой публикацию перевода одного из писем широко известного в Британии в конце 60-х – начале 70-х гг. XVIII в. публициста, писавшего под именем Юниус. Письма Юниуса стали сегодня классикой политической публицистики. Данное письмо обращено к премьер-министру его величества герцогу Графтону, санкционировавшему изгнание из нижней палаты британского парламента законно избранного представителя от Мидлсекса радикала и скандального публициста Дж. Уилкса. Юниус, не испытывающий никаких симпатий к последнему, показывает слабость и недальновидность правительства, а главное – незаконность его действий.Исследование выполнено при поддержке гранта Российского научного фонда (проект № 19-18-00186 «Культура духа» vs «Культура разума»: интеллектуалы и власть в Британии и России в эпоху перемен, XVII–XVIII вв.»)

Подход с комбинированием общего и узкоспециализированного семантического анализа в DLP-системах

The paper proposes an approach to combining general and highly specialized semantic analysis. The analysis of the main problems of the semantic analysis of the text is carried out, as well as an approach is proposed in which the semantic analysis in DLP systems immediately spreads to the entire protected system. The presented approach will allow to gradually accelerate the work of the DLP system, as well as analyze the result of the work of semantic analysis to evaluate and maintain semantic analysis in an up-to-date state. В данной работе были рассмотрены основные проблеме семантического анализа, а также предложен способ построения семантического анализа, который может обеспечить максимальную эффективность при минимальных временных затратах и уменьшит издержки при эксплуатации. Особенность подхода заключается в особом комбинировании общего семантического анализа с специализированным, постепенном увеличении скорости анализа в DLP-системе, визуализации анализа с возможностью улучшения работы семантического анализа. Под общим анализом тут понимается возможность анализировать текст любого рода, а специализированный тексты только определенной тематики. Постепенный плавный переход от общего к специализированному анализу позволяет увеличить скорость работы системы в тех тематических областях. Визуализация дает возможность более быстро анализировать и оценивать результат работы семантического анализа, позволяет сразу актуализировать справочники слов, необходимых для понимания смысла текста. Все эти действия позволяют DLP-системе быть в актуальном состоянии для предотвращения утечки информации

Cardioprotective effects of thioredoxin in myocardial ischemia and the reperfusion role of S-nitrosation

Apoptosis contributes to myocardial ischemia/reperfusion (MI/R) injury, and both thioredoxin (Trx) and nitric oxide have been shown to exert antiapoptotic effects in vitro. Recent evidence suggests that this particular action of Trx requires S-nitrosation at Cys-69. The present study sought to investigate whether or not exogenously applied Trx reduces MI/R injury in vivo and to which extent this effect depends on S-nitrosation. Adult mice were subjected to 30 min of MI and treated with either vehicle or human Trx (hTrx, 2 mg/kg, i.p.) 10 min before reperfusion. Native hTrx was incorporated into myocardial tissue as shown by immunostaining, and reduced MI/R injury as evidenced by decreased terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL) staining, DNA fragmentation, caspase-3 activity, and infarct size. When hTrx was partially S-nitrosated by preincubation with S-nitrosoglutathione, its cardioprotective effect was markedly enhanced. Treatment with hTrx significantly reduced p38 mitogen-activated protein kinase (MAPK) activity, and this effect was also potentiated by S-nitrosation. To further address the role of S-nitrosation for the overall antiapoptotic effect to Trx, the action of Escherichia coli Trx (eTrx) was investigated in the same model. Whereas eTrx inhibited MI/R-induced apoptosis to a degree similar to hTrx, S-nitrosation of this protein, which lacks Cys-69, failed to further enhance its antiapoptotic action. Collectively, our results demonstrate that systemically applied Trx is taken up by the myocardium to exert potent cardioprotective effects in vivo, offering interesting therapeutic avenues. In the case of hTrx, these effects are further potentiated by S-nitrosation, but this posttranslational modification is not essential for protection