Yana Feodorova

Quick and reliable method for retina dissociation and separation of rod photoreceptor perikarya from adult mice.

Graphical abstract

Psychological Stress – Cellular and Molecular Mechanisms

ABSTRACT Pathophysiological regulation of the stress response involves a number of complex interactions at the organismal, cellular and molecular levels. A salient feature of the stress response is the activation of the hypothalamic-pituitaryadrenal axis. Molecular studies of this phenomenon have found a number of genes which are differentially expressed in stressed individuals and control subjects. The transcription factor NF-κB controls many of these genes, which is evidence of the key role it plays in the cellular stress response. Stress upregulates a number of genes such as the transcription factor genes that control cell growth, chromatin structure, cell cycle activation and enzymes involved in the biosynthesis of nucleic acids and proteins. The genes that are down-regulated in stress are cell cycle inhibitors, apoptosis related genes, antiproliferative cytokines and Apo J, the NF-κB inhibitor. Post-traumatic stress disorder (PTSD) is an anxiety disorder which develops as a reaction to an extreme traumatic event but only in a small proportion of the population. It is still unknown what molecular mechanisms trigger its progression. Both genetic and epigenetic factors play a role in this condition. Although the environmental component is necessary for developing PTSD, it has been suggested that 30% of the variance in PTSD symptoms could be attributed to genetic influences. Utilizing genome wide association studies, it would be possible to identify new genes involved in PTSD development and elucidate the molecular pathways which are dysregulated. This will facilitate the identification of novel biomarkers that may help in PTSD diagnosis and treatment. РЕЗЮМЕ Патофизиологическая регуляция стрессового ответа включает сложные взаимодействия на уровне организма, клеток и молекул. Наиболее ярко проявленной характеристикой стрессового ответа является активирование оси гипоталамус - гипофиз - надпочечная железа. Молекулярные исследования стрессового ответа обнаруживают большое число генов, дифферен- цированно экспрессированных у индивидов, подверг- нутых стрессу и у здоровых лиц. Многие из них контролируются транскрипционным фактором NF-κB, утверждая его ключевую роль в клеточном стрессовом ответе. При стрессе сверхэкспрессированными являются: множество генов, которые кодируют транскрип- ционные факторы, контролирующих клеточный рост и дифференциацию; регуляторы хроматиновой структуры; молекулы, приводящие к активации клеточного цикла и энзимы, участвующие в биосин- тезе нуклеиновых кислот и белков. Список генов с пониженной экспрессией включает: ингибиторы клеточного цикла; гены, связанные с апоптозом; антипролиферативные цитокины и Аро J - ингибитор NF-κB. Посттравматическое стрессовое расстройство (ПТСР) представляет собой тревожное расстройство, возникающее как реакция вследствие экстремальной психологической травмы, но только у небольшой части людей. Все еще неизвестны молекулярные механизмы, которые запускают его прогрессию. ПТСР характеризуется также и нарушенной регуляцией оси гипоталамус - гипофиз - надпочечная железа. Удивляет тот факт, что пациенты, страдающие ПТСР, имеют более низкие уровни кортизола по сравнению с лицами контрольной группы. Свою роль при этом заболевании играют как генетические, так и эпигенетические механизмы. Несмотря на то, что окружающая среда является фактором, необходимым для возникновения ПТСР, предполагается, что 30% вариации в симптомах объясняется генетическими эффектами. Благо- даря использованию глобальных ассоциативных исследований генома (genome wide association studies) идентифицируются новые гены, связанные с возникновением ПТСР и накопляется детальная информация о дисрегулированных сигнальных пу- тях. Таким образом облегчится обнаружение новых биомаркеров, которые смогли бы улучшить диагностику и лечение ПТСР.

Synthesis and in vitro activity of platinum(II) complexes of two fluorenylspirohydantoins against a human tumour cell line

This paper presents a method for synthesis and cytotoxicity of new platinum(II) complexes of (9′-fluorene)-spiro-5-hydantoin (L1) and (9′-fluorene)-spiro-5-(2-thiohydantoin) (L2). The new obtained complexes were studied by elemental analysis: ultraviolet–visible, attenuated total reflection Fourier transform infrared (ATR-FTIR), and 1H- and 13C-NMR for Pt(II) compounds and additionally Raman spectroscopy for free ligands. Based on the experimental data, the most probable structure of the complexes is suggested. In the present study, we have examined cytotoxic activity of (9′-fluorene)-spiro-5-hydantoin (L1) and (9′-fluorene)-spiro-5-(2-thiohydantoin) (L2) and their Pt(II) complexes on the retinoblastoma cell line WERI-Rb-1.

Heterochromatin drives organization of conventional and inverted nuclei

The mammalian cell nucleus displays a remarkable spatial segregation of active euchromatic from inactive heterochromatic genomic regions. In conventional nuclei, euchromatin is localized in the nuclear interior and heterochromatin at the nuclear periphery. In contrast, rod photoreceptors in nocturnal mammals have inverted nuclei, with a dense heterochromatic core and a thin euchromatic outer shell. This inverted architecture likely converts rod nuclei into microlenses to facilitate nocturnal vision, and may relate to the absence of particular proteins that tether heterochromatin to the lamina. However, both the mechanism of inversion and the role of interactions between different types of chromatin and the lamina in nuclear organization remain unknown. To elucidate this mechanism we performed Hi-C and microscopy on cells with inverted nuclei and their conventional counterparts. Strikingly, despite the inversion evident in microscopy, both types of nuclei display similar Hi-C maps. To resolve this paradox we developed a polymer model of chromosomes and found a universal mechanism that reconciles Hi-C and microscopy for both inverted and conventional nuclei. Based solely on attraction between heterochromatic regions, this mechanism is sufficient to drive phase separation of euchromatin and heterochromatin and faithfully reproduces the 3D organization of inverted nuclei. When interactions between heterochromatin and the lamina are added, the same model recreates the conventional nuclear organization. To further test our models, we eliminated lamina interactions in models of conventional nuclei and found that this triggers a spontaneous process of inversion that qualitatively reproduces the pathway of morphological changes during nuclear inversion in vivo. Together, our experiments and modeling suggest that interactions among heterochromatic regions are central to phase separation of the active and inactive genome in inverted and conventional nuclei, while interactions with the lamina are essential for building the conventional architecture from these segregated phases. Ultimately our data suggest that an inverted organization constitutes the default state of nuclear architecture.

Investigation Of Chromium-Cobalt Coated Scaffolds On Cell Cultures In Vitro

Abstract Introduction: The use of diverse materials for medical purposes is continuously expanding. The modification of materials which are routinely applied in medical practice as well as the development and introduction of new materials require studies on their biological activity. The first steps in this process are the preliminary short-term screening tests for cytotoxicity and biocompatibility performed on cell cultures. Methods: Coating of stainless steel (316 L) scaffolds with chromium-cobalt was performed by electroplating using the non-standard electrolyte Chromispel. The process was carried through at different cathode current densities and deposition times. The modified surface of the metal scaffolds was studied for cytoxicity and cell vitality on the serum-free McCoy-Plovdiv and the immortalized PDL cell cultures. Results: Our results indicate no cytotoxic effect of the coated metal scaffolds. Even more, three of the samples stimulated the proliferation and growth of McCoy-Plovdiv cells. Conclusion: We have strong reasons to believe that chromium-cobalt coatings are promising for future studies and reliable for medical purposes.