Publications by authors named "Nikolay Kondratyev"

Article Synopsis
  • Mesenchymal stromal cells (MSCs) have significant potential in regenerative medicine but face challenges in classification, particularly for those from the pancreas; this study aims to better characterize pancreatic islet-derived MSCs (hPD-MSCs).
  • The hPD-MSCs were isolated from donor islets and analyzed through various methods, confirming they possess key MSC features and can differentiate into fat and bone cells, with unique gene expression patterns compared to MSCs from other tissues.
  • The findings reveal that hPD-MSCs share similarities with pancreatic stellate cells and identify specific genes related to pancreatic and neural functions, enhancing the understanding of their therapeutic potential.
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In recent decades, the chiral allylation of imines emerged as a key methodology in the synthesis of alkaloids and natural products with 4-, 5- and 6-membered cyclic amine motifs. Initially reliant on stoichiometric reagents, synthetic chemists predominantly used -substituted chiral imines, organometallic chiral reagents and achiral reagents with an equimolar chiral controller. However, recent years have witnessed the rise of asymmetric transition-metal catalysts and, importantly, organocatalytic allylation, reshaping the landscape of modern synthetic chemistry.

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  • Chromatin structure plays a crucial role in determining gene expression and cell identity, especially in neurons, through the action of polycomb group (PcG) proteins.
  • A study mapping the 3D genome in neuronal and non-neuronal cells from the Wernicke's area shows that neurons have less separation between active and inactive gene regions compared to other brain cells.
  • Neuronal cells display unique chromatin interactions, including a specific network of PcG contacts linked to genes that control development, with a distinct pattern of histone modifications that suggest a functional significance of these interactions for neuron identity.
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Introduction: Culturing of human neural stem cells (NSCs) derived from induced pluripotent stem cells (iPSC) is a promising area of research, as these cells have the potential to treat a wide range of neurological, neurodegenerative and psychiatric diseases. However, the development of optimal protocols for the production and long-term culturing of NSCs remains a challenge. One of the most important aspects of this problem is to determine the stability of NSCs during long-term in vitro passaging.

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  • The study explored how DNA methylation (DNAm) in a specific gene related to stress might connect genetic and environmental factors influencing schizophrenia symptoms.
  • Researchers analyzed blood samples from 66 schizophrenia patients and 63 controls using advanced sequencing techniques.
  • Results showed that while certain genetic variations (haplotype and VNTR) and environmental risk scores affected DNAm, the findings did not support the idea that this specific DNA region mediates the impact of these risk factors on schizophrenia symptoms.
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  • Complex traits are often polygenic and hereditary, making them scientifically intriguing but tough to study due to their complicated genetic makeup.
  • Traditional methods of reverse genetics struggle with these traits since they typically focus on single genes, while complex traits involve many genetic factors with small individual impacts.
  • This review seeks to help biologists understand and interpret GWAS results better, addressing common misconceptions and exploring how these results can be applied in further research on complex traits.
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A major problem in psychiatric research is a deficit of relevant cell material of neuronal origin, especially in large quantities from living individuals. One of the promising options is cells from the olfactory neuroepithelium, which contains neuronal progenitors that ensure the regeneration of olfactory receptors. These cells are easy to obtain with nasal biopsies and it is possible to grow and cultivate them in vitro.

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Large-scale epigenomic projects have mapped hundreds of thousands of potential regulatory sites in the human genome, but only a small proportion of these elements are proximal to transcription start sites. It is believed that the majority of these sequences are remote promoter-activating genomic sites scattered within several hundreds of kilobases from their cognate promoters and referred to as enhancers. It is still unclear what principles, aside from relative closeness in the linear genome, determine which promoter(s) is controlled by a given enhancer; however, this understanding is of great fundamental and clinical relevance.

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Interrogating DNA methylation within schizophrenia risk loci holds promise to identify mechanisms by which genes influence the disease. Based on the hypothesis that allele specific methylation (ASM) of a single CpG, or perhaps CpH, might mediate or mark the effects of genetic variants on disease risk and phenotypes, we explored haplotype specific methylation levels of individual cytosines within a genomic region harbouring the BAG5, APOPT1 and KLC1 genes in peripheral blood of schizophrenia patients and healthy controls. Three DNA fragments located in promoter, intronic and intergenic areas were studied by single-molecule real-time bisulfite sequencing enabling the analysis of long reads of DNA with base-pair resolution and the determination of haplotypes directly from sequencing data.

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Recent advances in psychiatric genetics have led to the discovery of dozens of genomic loci associated with schizophrenia. However, a gap exists between the detection of genetic associations and understanding the underlying molecular mechanisms. This review describes the basic approaches used in the so-called post-GWAS studies to generate biological interpretation of the existing population genetic data, including both molecular (creation and analysis of knockout animals, exploration of the transcriptional effects of common variants in human brain cells) and computational (fine-mapping of causal variability, gene set enrichment analysis, partitioned heritability analysis) methods.

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Schizophrenia is a highly polygenic disorder with important contributions from both common and rare risk alleles. We analyzed exome sequencing data for de novo variants (DNVs) in a new sample of 613 schizophrenia trios and combined this with published data to give a total of 3,444 trios. In this new data, loss-of-function (LoF) DNVs were significantly enriched among 3,471 LoF-intolerant genes, which supports previous findings.

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The study aimed to confirm the association of the schizophrenia genome-wide association study (GWAS) hit rs2514218 located near the DRD2 gene with the risk of the disease and to investigate the relationships between rs2514218 and schizophrenia-related clinical and neuroimaging phenotypes. Genotypes at the rs2514218 site were determined for 2148 schizophrenia spectrum patients and 1273 control subjects from the Russian population. In subsets of subjects, we assessed symptomatic dimensions using the Positive and Negative Syndrome Scale (n = 1651) and Temporal Experience of Pleasure Scale (n = 471).

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Genetic variation may impact on local DNA methylation patterns. Therefore, information about allele-specific DNA methylation (ASM) within disease-related loci has been proposed to be useful for the interpretation of GWAS results. To explore mechanisms that may underlie associations between Alzheimer's disease (AD) and schizophrenia risk CLU gene and verbal memory, one of the most affected cognitive domains in both conditions, we studied DNA methylation in a region between AD-associated SNPs rs9331888 and rs9331896 in 72 healthy individuals and 73 schizophrenia patients.

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Upon publication of the original article [1], it was noticed that the Figure captions of Figs. 2 and 3 were incorrectly given. The correct Figure captions are given below.

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Background: Methylation of DNA is associated with a variety of biological processes. With whole-genome studies of DNA methylation, it became possible to determine a set of genomic sites where DNA methylation is associated with a specific phenotype. A method is needed that allows detailed follow-up studies of the sites, including taking into account genetic information.

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Highly enantioenriched, chromatographically-stable secondary allyl boronates featuring a 1,1,2,2-tetraethyl-1,2-ethanediol fragment (Epin) were obtained by kinetic resolution of their racemic mixtures. The Epin group at boron considerably improved stability of allyl boronates allowing them to be readily isolated by chromatography on silica. The resolved reagents were applied in stereoselective synthesis of homoallylic amines with an internal double bond employing unprotected imines formed in situ from aldehydes and ammonia.

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A method for the coupling of organozinc reagents, difluorocarbene, and allylic electrophiles is described. The reaction involves insertion of difluorocarbene into the carbon-zinc bond followed by copper-catalyzed allylic substitution.

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