Репозиторий Университета

Objective. To assess antioxidant therapy (ascorbic acid (AA), Cytoflavin) prescribed as part of the standard treatment scheme based on clinical and morphological data in cerebral infarct. Materials and methods. The study was performed from 2010 to 2014 in eight vascular centers in the Russian Federation. A total of 373 patients with acute ischemic stroke in the carotid basin were studied. Group 1 consisted of 132 patients who received 5% AA solution at a daily dose of 20 ml; group 2 consisted of 113 patients receiving the antioxidant Cytoflavin at a daily dose of 20 ml for 10 days; group 3 consisted of 108 patients receiving Cytoflavin for 20 days, the dose being decreased to 10 ml from day 11 to day 20. Patients’ status was evaluated using a set of clinical, laboratory, and instrumented methods. Results and conclusions. Analysis of CT scan results obtained on treatment days 1 and 21 showed that Cytoflavin led to significant regression of the volume of cerebral ischemia, by an average factor of 1.5–1.7. No significant morphological changes were seen in the AA-treated group; among Cytoflavin-treated patients there was a two-fold reduction in the proportion of patients in which the volume of cerebral ischemia increased during the period 1–21 days. In patients with initial assessments of at least 14 points on the NIH scale, Cytoflavin treatment for 20 days promoted more marked improvements in neurological, functional, and cognitive status than seen in patients given infusions for 10 days.

Предложены новые номенклатурные комбинации: Aconitum brevipes (W. T. Wang) Luferov et Erst, A. grandibracteolatum (W. T. Wang) Luferov et Erst, A. trisectum (W. T. Wang et L. Q. Li) Luferov et Erst. Эти виды являются эндемиками Китая.

Повышение активности ренин-ангиотензин-альдостероновой системы - один из важнейших механизмов реализации сердечно-сосудистого континуума. Рассматривается роль, которую блокаторы рецепторов ангиотензина играют в достижении целевых цифр артериального давления и снижении сердечно-сосудистого риска. Освещается значение плейотропных свойств блокаторов рецепторов ангиотензина (в частности, активации гамма рецепторов, активируемых пероксисомными пролифераторами - PPAR-y) в ведении больных с инсулинорезистентностью, ожирением, дислипидемией. Обсуждается доказательная база применения телмисартана как препарата, обладающего плейотропным действием, у больных с артериальной гипертензией и сочетанными заболеваниями (сахарный диабет, ожирение, нарушение функции почек).

Biological effects of hormones in both plants and animals are based on high-affinity interaction with cognate receptors resulting in their activation. The signal of cytokinins, classical plant hormones, is perceived in Arabidopsis by three homologous membrane receptors: AHK2, AHK3, and CRE1/AHK4. To study the cytokinin-receptor interaction, we used 25 derivatives of potent cytokinin N6-benzyladenine (BA) with substituents in the purine heterocycle and/or in the side chain. The study was focused primarily on individual cytokinin receptors from Arabidopsis. The main in planta assay system was based on Arabidopsis double mutants retaining only one isoform of cytokinin receptors and harboring cytokinin-sensitive reporter gene. Classical cytokinin biotest with Amaranthus seedlings was used as an additional biotest. In parallel, the binding of ligands to individual cytokinin receptors was assessed in the in vitro test system. Quantitative comparison of results of different assays confirmed the partial similarity of ligand-binding properties of receptor isoforms. Substituents at positions 8 and 9 of adenine moiety, elongated linker up to 4 methylene units, and replacement of N6 by sulfur or oxygen have resulted in the suppression of cytokinin activity of the derivative toward all receptors. Introduction of a halogen into position 2 of adenine moiety, on the contrary, often increased the ligand activity, especially toward AHK3. Features both common and distinctive of cytokinin receptors in Arabidopsis and Amaranthus were revealed, highlighting species specificity of the cytokinin perception apparatus. Correlations between the extent to which a compound binds to a receptor in vitro and its ability to activate the same receptor in planta were evaluated for each AHK protein. Interaction patterns between individual receptors and ligands were rationalized by structure analysis and molecular docking in sensory modules of AHK receptors. The best correlation between docking scores and specific binding was observed for AHK3. In addition, receptor-specific ligands have been discovered with unique properties to predominantly activate or block distinct cytokinin receptors. These ligands are promising for practical application and as molecular tools in the study of the cytokinin perception by plant cells.

Chronic hepatitis B virus (HBV) infection has long remained a critical global health issue. Covalently closed circular DNA (cccDNA) is a persistent form of the HBV genome that maintains HBV chronicity. Decades of extensive research resulted in the two therapeutic options currently available: nucleot(s)ide analogs and interferon (IFN) therapy. A plethora of reliable markers to monitor HBV patients has been established, including the recently discovered encapsidated pregenomic RNA in serum, which can be used to determine treatment end-points and to predict the susceptibility of patients to IFN. Additionally, HBV RNA splice variants and cccDNA and its epigenetic modifications are associated with the clinical course and risks of hepatocellular carcinoma (HCC) and liver fibrosis. However, new antivirals, including CRISPR/Cas9, APOBEC-mediated degradation of cccDNA, and T-cell therapies aim at completely eliminating HBV, and it is clear that the diagnostic arsenal for defining the long-awaited sterilizing cure is missing. In this review, we discuss the currently available tools for detecting and measuring HBV RNAs and cccDNA, as well as the state-of-the-art in clinical implications of these markers, and debate needs and goals within the context of the sterilizing cure that is soon to come. View Full-Text

Osteoarthritis (OA), the most common form of arthritis, is characterized by inflammation of joints and cartilage degradation leading to disability, discomfort, severe pain, inflammation, and stiffness of the joint. It has been shown that adenosine, a purine nucleoside composed of adenine attached to ribofuranose, is enzymatically produced by the human synovium. However, the functional significance of adenosine signaling in homeostasis and pathology of synovial joints remains unclear. Adenosine acts through four cell surface receptors, i.e., A1, A2A, A2B, and A3, and here, we have systematically analyzed mice with a deficiency for A3 receptor as well as pharmacological modulations of this receptor with specific analogs. The data show that adenosine receptor signaling plays an essential role in downregulating catabolic mechanisms resulting in prevention of cartilage degeneration. Ablation of A3 resulted in development of OA in aged mice. Mechanistically, A3 signaling inhibited cellular catabolic processes in chondrocytes including downregulation of Ca2+/calmodulin-dependent protein kinase (CaMKII), an enzyme that promotes matrix degradation and inflammation, as well as Runt-related transcription factor 2 (RUNX2). Additionally, selective A3 agonists protected chondrocytes from cell apoptosis caused by pro-inflammatory cytokines or hypo-osmotic stress. These novel data illuminate the protective role of A3, which is mediated via inhibition of intracellular CaMKII kinase and RUNX2 transcription factor, the two major pro-catabolic regulators in articular cartilage.

Sequential courses of anticancer target therapy lead to selection of drug-resistant cells, which results in continuous decrease of clinical response. Here we present a new approach for predicting effective combinations of target drugs, which act in a synergistic manner. Synergistic combinations of drugs may prevent or postpone acquired resistance, thus increasing treatment efficiency. We cultured human ovarian carcinoma SKOV-3 and neuroblastoma NGP-127 cancer cell lines in the presence of Tyrosine Kinase Inhibitors (Pazopanib, Sorafenib, and Sunitinib) and Rapalogues (Temsirolimus and Everolimus) for four months and obtained cell lines demonstrating increased drug resistance. We investigated gene expression profiles of intact and resistant cells by microarrays and analyzed alterations in 378 cancer-related signaling pathways using the bioinformatical platform Oncobox. This revealed numerous pathways linked with development of drug resistant phenotypes. Our approach is based on targeting proteins involved in as many as possible signaling pathways upregulated in resistant cells. We tested 13 combinations of drugs and/or selective inhibitors predicted by Oncobox and 10 random combinations. Synergy scores for Oncobox predictions were significantly higher than for randomly selected drug combinations. Thus, the proposed approach significantly outperforms random selection of drugs and can be adopted to enhance discovery of new synergistic combinations of anticancer target drugs. View Full-Text

Biological effects of hormones in both plants and animals are based on high-affinity interaction with cognate receptors resulting in their activation. The signal of cytokinins, classical plant hormones, is perceived in Arabidopsis by three homologous membrane receptors: AHK2, AHK3, and CRE1/AHK4. To study the cytokinin-receptor interaction, we used 25 derivatives of potent cytokinin N6-benzyladenine (BA) with substituents in the purine heterocycle and/or in the side chain. The study was focused primarily on individual cytokinin receptors from Arabidopsis. The main in planta assay system was based on Arabidopsis double mutants retaining only one isoform of cytokinin receptors and harboring cytokinin-sensitive reporter gene. Classical cytokinin biotest with Amaranthus seedlings was used as an additional biotest. In parallel, the binding of ligands to individual cytokinin receptors was assessed in the in vitro test system. Quantitative comparison of results of different assays confirmed the partial similarity of ligand-binding properties of receptor isoforms. Substituents at positions 8 and 9 of adenine moiety, elongated linker up to 4 methylene units, and replacement of N6 by sulfur or oxygen have resulted in the suppression of cytokinin activity of the derivative toward all receptors. Introduction of a halogen into position 2 of adenine moiety, on the contrary, often increased the ligand activity, especially toward AHK3. Features both common and distinctive of cytokinin receptors in Arabidopsis and Amaranthus were revealed, highlighting species specificity of the cytokinin perception apparatus. Correlations between the extent to which a compound binds to a receptor in vitro and its ability to activate the same receptor in planta were evaluated for each AHK protein. Interaction patterns between individual receptors and ligands were rationalized by structure analysis and molecular docking in sensory modules of AHK receptors. The best correlation between docking scores and specific binding was observed for AHK3. In addition, receptor-specific ligands have been discovered with unique properties to predominantly activate or block distinct cytokinin receptors. These ligands are promising for practical application and as molecular tools in the study of the cytokinin perception by plant cells.

Chronic hepatitis B virus (HBV) infection has long remained a critical global health issue. Covalently closed circular DNA (cccDNA) is a persistent form of the HBV genome that maintains HBV chronicity. Decades of extensive research resulted in the two therapeutic options currently available: nucleot(s)ide analogs and interferon (IFN) therapy. A plethora of reliable markers to monitor HBV patients has been established, including the recently discovered encapsidated pregenomic RNA in serum, which can be used to determine treatment end-points and to predict the susceptibility of patients to IFN. Additionally, HBV RNA splice variants and cccDNA and its epigenetic modifications are associated with the clinical course and risks of hepatocellular carcinoma (HCC) and liver fibrosis. However, new antivirals, including CRISPR/Cas9, APOBEC-mediated degradation of cccDNA, and T-cell therapies aim at completely eliminating HBV, and it is clear that the diagnostic arsenal for defining the long-awaited sterilizing cure is missing. In this review, we discuss the currently available tools for detecting and measuring HBV RNAs and cccDNA, as well as the state-of-the-art in clinical implications of these markers, and debate needs and goals within the context of the sterilizing cure that is soon to come. View Full-Text

Osteoarthritis (OA), the most common form of arthritis, is characterized by inflammation of joints and cartilage degradation leading to disability, discomfort, severe pain, inflammation, and stiffness of the joint. It has been shown that adenosine, a purine nucleoside composed of adenine attached to ribofuranose, is enzymatically produced by the human synovium. However, the functional significance of adenosine signaling in homeostasis and pathology of synovial joints remains unclear. Adenosine acts through four cell surface receptors, i.e., A1, A2A, A2B, and A3, and here, we have systematically analyzed mice with a deficiency for A3 receptor as well as pharmacological modulations of this receptor with specific analogs. The data show that adenosine receptor signaling plays an essential role in downregulating catabolic mechanisms resulting in prevention of cartilage degeneration. Ablation of A3 resulted in development of OA in aged mice. Mechanistically, A3 signaling inhibited cellular catabolic processes in chondrocytes including downregulation of Ca2+/calmodulin-dependent protein kinase (CaMKII), an enzyme that promotes matrix degradation and inflammation, as well as Runt-related transcription factor 2 (RUNX2). Additionally, selective A3 agonists protected chondrocytes from cell apoptosis caused by pro-inflammatory cytokines or hypo-osmotic stress. These novel data illuminate the protective role of A3, which is mediated via inhibition of intracellular CaMKII kinase and RUNX2 transcription factor, the two major pro-catabolic regulators in articular cartilage.

Sequential courses of anticancer target therapy lead to selection of drug-resistant cells, which results in continuous decrease of clinical response. Here we present a new approach for predicting effective combinations of target drugs, which act in a synergistic manner. Synergistic combinations of drugs may prevent or postpone acquired resistance, thus increasing treatment efficiency. We cultured human ovarian carcinoma SKOV-3 and neuroblastoma NGP-127 cancer cell lines in the presence of Tyrosine Kinase Inhibitors (Pazopanib, Sorafenib, and Sunitinib) and Rapalogues (Temsirolimus and Everolimus) for four months and obtained cell lines demonstrating increased drug resistance. We investigated gene expression profiles of intact and resistant cells by microarrays and analyzed alterations in 378 cancer-related signaling pathways using the bioinformatical platform Oncobox. This revealed numerous pathways linked with development of drug resistant phenotypes. Our approach is based on targeting proteins involved in as many as possible signaling pathways upregulated in resistant cells. We tested 13 combinations of drugs and/or selective inhibitors predicted by Oncobox and 10 random combinations. Synergy scores for Oncobox predictions were significantly higher than for randomly selected drug combinations. Thus, the proposed approach significantly outperforms random selection of drugs and can be adopted to enhance discovery of new synergistic combinations of anticancer target drugs. View Full-Text

Репликативный полипротеин 1а вируса желтухи свеклы (ВЖС) содержит консервативные домены лидерной папаин-подобной протеиназы (РСР), метилтрансферазы (MTR) и РНК хеликазы (HEL). Центральный район (central region, CR) между MTR и HEL ранее считали «вариабельным». Нами проведен компьютерный анализ CR, который позволил выявить новый консервативный домен между позициями 1287-1390 (здесь и далее приводится нумерация аминокислотных остатков белка 1а вируса желтухи свеклы, BYV), сохраняющийся у всех представителей рода Closterovirus. Этот домен содержит 4 предсказанных альфа-спиральных участка (альфа А – D) и три строго консервативные позиции – глютамат-1291, пролин-1380 и аргинин-1384. Кроме того, биоинформатический анализ позволил предсказать амфипатическую спираль в позициях 1368-1380 (входящую в состав участка альфа D). Гидрофобный домен CR-2 (позиции 1305-1494 белка 1а), вызывающий при экспрессии в растениях реструктуризацию эндоплазматического ретикулюма и образование подвижных глобул диаметром ~1 мкм, включает участки альфа В, С и D. Установлено, что экспрессия в растениях слитных белков CR-2:GFP и GFP:CR-2 вызывает сходный «глобулообразующий» фенотип, т.е. N-концевое или C-концевое положение маркера GFP в слитном белке не влияет на переформатирование мембран эндоплазматического ретикулюма. Проведен делеционный анализ CR-2 BYV. Показано, что делеционные варианты 1355-1494 и 1325-1484 сохраняют фенотип дикого типа (образование глобул и реструктуризация ЭР вокруг ядра клетки). Варианты 1375-1484, 1368-1484 и 1368-1432 индуцировали образование глобул, но утрачивали способность к реструктуризации ЭР. Внесение замен гидрофобных аминокислотных остатков на остатки серина и глицина в «минимальном» делеционном мутанте 1368-1432 блокировало образование глобул. Предложена рабочая гипотеза о влиянии консервативной амфипатической спирали 1368-1385 в белке 1а BYV на ремоделирование мембран ЭР растительной клетки и создание репликативных платформ при клостеровирусной инфекции.

Human B-cell receptor-associated protein BAP31 (HsBAP31) is the endoplasmic reticulum-resident protein involved in protein sorting and transport as well as pro-apoptotic signaling. Plant orthologs of HsBAP31 termed 'plant BAP-like proteins' (PBL proteins) have thus far remained unstudied. Recently, the PBL protein from Nicotiana tabacum (NtPBL) was identified as an interactor of Nt-4/1, a plant protein known to interact with plant virus movement proteins and affect the long-distance transport of potato spindle tuber viroid (PSTVd) via the phloem. Here, we have compared the sequences of PBL proteins and studied the biochemical properties of NtPBL. Analysis of a number of fully sequenced plant genomes revealed that PBL-encoding genes represent a small multigene family with up to six members per genome. Two conserved motifs were identified in the C-terminal region of PBL proteins. The NtPBL C-terminal hydrophilic region (NtPBL-C) was expressed in bacterial cells, purified, and used for analysis of its RNA binding properties in vitro. In gel shift experiments, NtPBL-C was found to bind several tested RNAs, showing the most efficient binding to microRNA precursors (pre-miRNA) and less efficient interaction with PSTVd. Mutational analysis suggested that NtPBL-C has a composite RNA-binding site, with two conserved lysine residues in the most C-terminal protein region being involved in binding of pre-miRNA but not PSTVd RNA. Virus-mediated transient expression of NtPBL-C in plants resulted in stunting and leaf malformation, developmental abnormalities similar to those described previously for blockage of miRNA biogenesis/function. We hypothesize that the NtPBL protein represents a previously undiscovered component of the miRNA pathway.

Autophagy is an evolutionary conserved intracellular catabolic process of vital importance to cell and tissue homeostasis. Autophagy is implicated in the pathogenesis of atherosclerosis but participating cells, molecular mechanisms and functional outcomes have not been fully elucidated. T-cadherin, an atypical glycosylphosphatidylinositol-anchored member of the cadherin superfamily of adhesion molecules, is upregulated on smooth muscle cells (SMCs)¹ in atherosclerotic lesions. Here, using rat and murine aortic SMCs as experimental models, we surveyed the ability of T-cadherin to regulate autophagy in SMCs during serum-starvation stress. Ectopic upregulation of T-cadherin in SMCs resulted in augmented autophagy characterized by increased autophagic flux, LC3-II abundance and autophagosome formation. Analysis of signal transduction pathway effectors and use of specific pharmacological inhibitors demonstrated that T-cadherin-associated enhancement of the autophagic response to serum-deprivation was dependent on MEK1/2/Erk1/2 activation and independent of PI3K/Akt/mTORC1, reactive oxygen species or endoplasmic reticulum stress. T-cadherin upregulation on SMCs conferred a survival advantage during prolonged serum-starvation which was sensitive to inhibition of MEK1/2/Erk1/2 by PD98059 or UO126 and to blockade of autophagy by chloroquine. Loss of T-cadherin expression in SMCs diminished autophagy responsiveness and compromised survival under conditions of serum-starvation. Overall our findings have identified T-cadherin as a novel positive regulator of autophagy and survival in SMCs.

Objective. To assess antioxidant therapy (ascorbic acid (AA), Cytoflavin) prescribed as part of the standard treatment scheme based on clinical and morphological data in cerebral infarct. Materials and methods. The study was performed from 2010 to 2014 in eight vascular centers in the Russian Federation. A total of 373 patients with acute ischemic stroke in the carotid basin were studied. Group 1 consisted of 132 patients who received 5% AA solution at a daily dose of 20 ml; group 2 consisted of 113 patients receiving the antioxidant Cytoflavin at a daily dose of 20 ml for 10 days; group 3 consisted of 108 patients receiving Cytoflavin for 20 days, the dose being decreased to 10 ml from day 11 to day 20. Patients’ status was evaluated using a set of clinical, laboratory, and instrumented methods. Results and conclusions. Analysis of CT scan results obtained on treatment days 1 and 21 showed that Cytoflavin led to significant regression of the volume of cerebral ischemia, by an average factor of 1.5–1.7. No significant morphological changes were seen in the AA-treated group; among Cytoflavin-treated patients there was a two-fold reduction in the proportion of patients in which the volume of cerebral ischemia increased during the period 1–21 days. In patients with initial assessments of at least 14 points on the NIH scale, Cytoflavin treatment for 20 days promoted more marked improvements in neurological, functional, and cognitive status than seen in patients given infusions for 10 days.

Предложены новые номенклатурные комбинации: Aconitum brevipes (W. T. Wang) Luferov et Erst, A. grandibracteolatum (W. T. Wang) Luferov et Erst, A. trisectum (W. T. Wang et L. Q. Li) Luferov et Erst. Эти виды являются эндемиками Китая.

Повышение активности ренин-ангиотензин-альдостероновой системы - один из важнейших механизмов реализации сердечно-сосудистого континуума. Рассматривается роль, которую блокаторы рецепторов ангиотензина играют в достижении целевых цифр артериального давления и снижении сердечно-сосудистого риска. Освещается значение плейотропных свойств блокаторов рецепторов ангиотензина (в частности, активации гамма рецепторов, активируемых пероксисомными пролифераторами - PPAR-y) в ведении больных с инсулинорезистентностью, ожирением, дислипидемией. Обсуждается доказательная база применения телмисартана как препарата, обладающего плейотропным действием, у больных с артериальной гипертензией и сочетанными заболеваниями (сахарный диабет, ожирение, нарушение функции почек).