NMR assignments of the N-terminal domain of Ogataea polymorpha telomerase reverse transcriptase

© 2015 Springer Science+Business Media Dordrecht Telomerase is a ribonucleoprotein enzyme that adds telomeric DNA fragments to the ends of chromosomes. This enzyme is the focus of substantial attention, both because its structure and mechanism of action are still poorly studied, and because of its pivotal roles in aging and cellular proliferation. The use of telomerase as a potential target for the design of new anticancer drugs is also of great interest. The catalytic protein subunit of telomerase (TERT) contains an N-terminal domain (TEN) that is essential for activity and processivity. Elucidation of the structure and dynamics of TEN in solution is important for understanding the molecular mechanism of telomerase activity and for the design of new telomerase inhibitors. To approach this problem, in this study we report the 1H, 13C, and 15N chemical shift assignments of TEN from Ogataea polymorpha. Analysis of the assigned chemical shifts allowed us to identify secondary structures and protein regions potentially involved in interaction with other participants of the telomerase catalytic cycle

NMR assignments of the N-terminal domain of Ogataea polymorpha telomerase reverse transcriptase

© 2015, Springer Science+Business Media Dordrecht.Telomerase is a ribonucleoprotein enzyme that adds telomeric DNA fragments to the ends of chromosomes. This enzyme is the focus of substantial attention, both because its structure and mechanism of action are still poorly studied, and because of its pivotal roles in aging and cellular proliferation. The use of telomerase as a potential target for the design of new anticancer drugs is also of great interest. The catalytic protein subunit of telomerase (TERT) contains an N-terminal domain (TEN) that is essential for activity and processivity. Elucidation of the structure and dynamics of TEN in solution is important for understanding the molecular mechanism of telomerase activity and for the design of new telomerase inhibitors. To approach this problem, in this study we report the 1H, 13C, and 15N chemical shift assignments of TEN from Ogataea polymorpha. Analysis of the assigned chemical shifts allowed us to identify secondary structures and protein regions potentially involved in interaction with other participants of the telomerase catalytic cycle

Exposure of Nuclear Track Emulsion to a Mixed Beam of Relativistic 12^{12}N, 10^{10}C, and 7^7Be Nuclei

A nuclear track emulsion was exposed to a mixed beam of relativistic $^{12}$N, $^{10}$C, and $^7$Be nuclei having a momentum of 2 GeV/$c$ per nucleon. The beam was formed upon charge exchange processes involving $^{12}$C primary nuclei and their fragmentation. An analysis indicates that $^{10}$C nuclei are dominant in the beam and that $^{12}$N nuclei are present in it. The charge topology of relativistic fragments in the coherent dissociation of these nuclei is presented.Comment: ISSN 1063-7788, Pleiades Publishing, Ltd., 201

Experience in Utilization of Phylogenetic Analysis for Epidemiological Investigation of HIV Infection Case

Objective of the study was to investigate a criminal case of infection with HIV, applying molecular-genetic analysis of blood plasma samples from an estimated source of an infection and the recipient for evaluation of probability of epidemiological connection between them. Materials and methods. The study involved genotyping and phylogenetic analysis of nucleotide sequences of HIV-1 variants, isolated from patients in the investigated group and the control one (19 nucleotide sequences of the HIV-1 from the patients living in the Saratov region, and 15 nucleotide sequences from GenBank). Genotyping was performed using the commercial ViroSeq HIV-1 Genotyping System. The sub-typing of HIV-1 strains was carried out on-line, through the COMET HIV-1/2 and HCV and REGA HIV-1 Sybtyping Tool programs. Phylogenetic analysis of nucleotide sequences was carried out by Mega software, version 5.2. Phylogenetic trees were constructed; nucleotide distances were calculated by Kimura method (bootstrap level 1000). Results and conclusions. Virus variants, isolated from the studied samples, were defined as HIV-1 A subtype. Performed phylogenetic analysis showed that nucleotide sequences of the studied samples authentically grouped on the phylogenetic tree, forming a common cluster, which mismatched that of control group. Calculation of the genetic distance testifies that the genetic relation between the samples within the investigated group is higher, than between the same samples and those of the control group. Thus, by means of phylogenetic analysis it is shown that the strains received from an estimated source of infection and the recipient are genetically closer to each other, than to the strains from the group of comparison. In this regard, it is possible to claim with a big share of confidence that probability of epidemiological connection between them exists

10He low-lying states structure uncovered by correlations

The 0+ ground state of the 10He nucleus produced in the 3H(8He,p)10He reaction was found at about $2.1\pm0.2$ MeV (\Gamma ~ 2 MeV) above the three-body 8He+n+n breakup threshold. Angular correlations observed for 10He decay products show prominent interference patterns allowing to draw conclusions about the structure of low-energy excited states. We interpret the observed correlations as a coherent superposition of the broad 1- state having a maximum at energy 4-6 MeV and the 2+ state above 6 MeV, setting both on top of the 0+ state "tail". This anomalous level ordering indicates that the breakdown of the N=8 shell known in 12Be thus extends also to the 10He system.Comment: 5 pages, 5 figure

Involvement of Urokinase-Type Plasminogen Activator Receptor in the Formation of a Profibrotic Microenvironment in the Epicardial Region

The study of the mechanisms of development and progression of fibrosis is one of the key directions of modern cardiology. Our work suggests that the urokinase receptor (uPAR) is involved in the regulation of mesothelial cell activity and epicardial fibrosis development, which, when interacting with specific ligands and intermediate proteins, can activate intracellular signaling, trigger the cascade of proteolytic reactions, including local plasmin formation and activation of matrix metalloproteinases, providing matrix remodeling.Objective: to perform a comparative study of fibrogenic activity of the epicardium in the hearts of uPAR-/- and wild-type animals and evaluate the effect of cardiac microenvironment factors on the migration activity of epicardial mesothelial cells.Material and methods. We used histological and immunofluorescent staining, microarray analysis of proinflammatory cytokine levels, and a method for assessing the migratory properties of epicardial cells.Results. Results. We found that compared to wild-type animals, uPAR-/- animals show significant thickening of the epicardial area (2.46+0.77 (uPAR-/- mice) and 1.02+0.17 (Wt mice) relative units, P=0.033) accompanied by accumulation of extracellular matrix proteins. Deficiency of uPAR gene leads to formation of proinflammatory microenvironment in the heart (increased levels of proinflammatory factors such as IL-1, IL-13, IL-17, RANTES and MIP1), increased migratory activity of epicardial mesothelial cells, accumulation of TCF21+fibroblast/myofibroblast precursors (29.8+13.7 (uPAR-/- mouse) and 3.03+0.8 (Wt mouse) cells per visual field,P=0.02), as well as development of subepicardial fibrosis.Conclusion. These findings suggest that uPAR is a promising candidate for the developing targeted agents to prevent the development and progression of cardiac fibrosis

Механизм действия фоллистатин-подобного белка-1 (FSTL-1)

The paper provides current data on some proteins of the TGF- p family which are potentially capable of exerting a protective effect in diseases of the heart, lungs, placenta, gonads, and pancreas. The study investigated the anti-inflammatory properties of follistatin-like protein-1 (FSTL-1), one of the proteins of this family, at the cellular level. It was demonstrated that FSTL-1 is responsible for heart muscle regeneration in mammals through activation of angiogenic factors. Despite the fact that this protein plays a key role in myocardial regeneration, its concentration in the epicardium decreases immediately after a heart attack, which hampers effective self-repair of the heart. The paper summarises the results of studies of the efficacy of intravenous administration of FSTL-1 in rats with myocardial infarction. However, the administration of a foreign protein can cause allergic reactions, therefore a drug that induces FSTL-1 secretion was chosen instead.The aim of the study was to provide experimental substantiation of the possibility of exogenous regulation of FSTL-1 secretion.Materials and methods: FSTL-1 concentration in rat plasma was assessed by enzyme immunoassay before and after treatment with the antioxidant drug ethyl methyl hydroxypyridine malate. The antioxidant was administered to 15 healthy male Wistar rats subcutaneously 3 times a day at a dose of 6 mg/day for 14 days. A fasting blood sample was obtained on the first day before administration of the drug and on day 15.Results: after the period of treatment with ethyl methyl hydroxypyridine malate the concentration of FSTL-1 in the plasma of the laboratory rats increased significantly (p = 0.0011) to reach 0.92 ± 0.11 ng/mL as compared to the initial concentration of 0.48 ± 0.04 ng/mL.Conclusion: the study provided experimental evidence for new properties of ethyl methyl hydroxypyridine malate, i.e. induction of FSTL-1 in healthy rats. Further studies are encouraged to assess potential use of this drug as an inductor of FSTL-1 in myocardial ischemia.Приведены современные данные о некоторых белках семейства TGF-p, потенциально способных оказывать протективное действие при патологиях сердца, легких, плаценты, половых желез и поджелудочной железы. Были изучены противовоспалительные свойства одного из представителей данного семейства белков — фоллистатин-подобного белка-1 (FSTL-1) на клеточном уровне. Установлено, что FSTL-1 отвечает за регенерацию сердечной мышцы у млекопитающих за счет активации ангиогенных факторов. Несмотря на ведущую роль данного белка в регенерации миокарда, его концентрация в эпикарде сразу после инфаркта уменьшается, что не позволяет сердцу эффективно са-мовосстанавливаться. Приведены данные исследований об эффективности внутривенного введения FSTL-1 у крыс с инфарктом миокарда. Однако поскольку введение чужеродного белка может вызывать аллергические реакции, более рациональным решением стал выбор лекарственного средства, индуцирующего секрецию FSTL-1.Цель работы: экспериментальное обоснование возможности применения экзогенной регуляции секреции фоллистатин-подобного белка-1.Материалы и методы: исследования концентрации FSTL-1 в плазме крыс проводили методом иммуноферментного анализа до и после курса применения антиоксидантного лекарственного средства этилметилгидроксипири-дина малата. Антиоксидант вводили 15 здоровым самцам крыс линии Wistar подкожно 3 раза в сутки в дозе 6 мг/сут, курсом 14 сут. Кровь отбирали из вены натощак в первые сутки до введения препарата и на 15 сут.Результаты: после курса введения этилметилгидроксипиридин малата концентрация FSTL-1 в плазме крови крыс достоверно (р = 0,0011) увеличивалась у экспериментальных животных и составила 0,92 ± 0,11 нг/мл относительно исходного значения 0,48 ± 0,04 нг/мл.Заключение: экспериментально подтверждены новые свойства этилметилгидроксипиридина малата — индукция фоллистатин-подобного белка-1 у здоровых крыс. Предлагается рассмотреть потенциальную возможность применения данного лекарственного средства как индуктора FSTL-1 при ишемии миокарда

3D сфероиды - клеточная модель для изучения воздействия гипоксии на эпикардиальное микроокружение

Fundamental research in recent years has allowed us to reassess the molecular and cellular mechanisms of cardiac ontogenesis and its repair after damage. The epicardium, the outer, tightly adjoining layer of the cardiac wall formed by epicardial mesothelial cells, collagen and elastic fibers, has gained special relevance as an important participant of reparative processes. Better insight into poorly understood epicardial function is challenged due to anatomical issues and lack of relevant cellular models.The aim of this study was to develop a spheroid 3D model of the epicardial microenvironment and determine responses of spheroids to hypoxia.Materials and methods. Spheroids were harvested in V-shaped culture dishes with a low adhesion coating. Immunofluorescent staining of cryosections, histological methods and real-time PCR were used for characterization of cultured spheroids.Results. We demonstrated that cultivation of cells under low adhesion conditions in V-shaped culture dishes resulted in the formation of spheroids with an average size of 136+21 µm and cell viability rates of over 98%. The cells in the spheroids cultured under normoxic conditions formed tight junctions and were characterized by a low level of proliferation and the ability to synthesize extracellular matrix proteins. Under hypoxia cells in the spheroids showed partial loss of intercellular contacts, acquired a spindle shape, started to express HIF1a, SNAIL, COL1Al and accumulate collagen. All these features demonstrated the activation of mesothelial(endothelial)-mesenchymal transition strongly resembling epicardial cellular responses to ischemia in vivo.Conclusion. An epicardial spheroid cell culture model suitable for study cellular responses to hypoxic environment was developed. This model can be used to clarify mechanisms regulating epicardial microenvironment and test new targeted candidate drugs.Фундаментальные исследования последних лет позволили переосмыслить молекулярные и клеточные механизмы онтогенеза сердца и его репарации после повреждения. Особую актуальность приобретает изучение эпикарда — наружного, плотно примыкающего к миокарду слоя сердечной стенки, образованного гетерогенной популяцией клеток эпикардиального мезотелия, коллагеновыми и эластическими волокнами, являющегося важным участником репаративных процессов. Изучение эпикарда затруднено в связи с анатомическими ограничениями и отсутствием релевантных клеточных моделей.Цель исследования. Разработка 3D модели эпикардиального микроокружения и оценка влияния гипоксии на ее характеристики.Материал и методы. Сборку сфероидов проводили в V-образных культуральных чашках с низкоадгезионным покрытием. Характеристику сфероидов выполняли с использованием иммунофлуоресцентного окрашивания криосрезов, гистологических методов, ПЦР в реальном времени.Результаты. Культивирование клеток в низкоадгезионных условиях в V-образных культуральных чашках ведет к формированию сфероидов, имеющих размер 136±21 мкм и показатели жизнеспособности клеток более 98%. Клетки в составе сфероидов, культивированных в условиях нормоксии, образовывали плотные межклеточные контакты, характеризовались низким уровнем пролиферации и способностью синтезировать белки внеклеточного матрикса. В условиях гипоксии клетки сфероидов частично утрачивали межклеточные контакты, приобретали веретенообразную форму, экспрессировали HIF1a, SNAI1, ACTA2, FN1, COL1A1 и накапливали коллаген, что указывает на признаки активации мезотелиально-мезенхимального перехода и сходные черты с клеточным ответом эпикарда на острое ишемическое повреждение in vivo.Заключение. На основе клеточного сфероида разработали и охарактеризовали модель эпикарда, которая может реализовать клеточный ответ на воздействие гипоксического стимула и быть использована для изучения механизмов регуляции эпикардиального микроокружения, тестирования лекарственных препаратов направленного действия