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77 Publications visible to you, out of a total of 77

Abstract (Expand)

Background: Posttraumatic stress disorder (PTSD) is a complex severe polygenic psychiatric disease, influenced by environmental and genetic factors. PTSD development and progression is characterized by cognitive impairment, which may result in altered processes of nervous system development and synaptic plasticity, where a number of growth factors and their receptors were shown to play important role. Since neurotrophins play an essential role in the development of central nervous system, it is widely implicated in psychiatric disorders. The aim of this study is to investigate the potential association functional polymorphisms of genes encoding netrin G1 (NTNG1), brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and its receptor (NGFR) with PTSD. Methods: Study groups consisted of 200 combat veterans with PTSD and an equal number of controls with no family or past history of any psychiatric disorders. The DNA samples were genotyped for NTNG1 rs62811; BDNF rs6265; NGF rs6330, rs4839435; NGFR rs11466155, rs734194 SNPs using polymerase chain reaction with sequence specific primers. Results: According to the results, NGF rs6330 was overrepresented in patients with PTSD compared to controls. Furthermore, negative association for BDNF rs6265, NGF rs4839435 and NGFR rs734194 was observed in PTSD patients. Conclusions: In summary, BDNF rs6265, NGF rs6330, rs4839435 and NGFR rs734194 are implicated in PTSD in Armenian population. However, further research is required to provide the definitive evidence of selected polymorphism association with gene expression.

Authors: Diana Avetyan, Arsen Arakelyan, Gohar Mkrtchyan

Date Published: 11th Jan 2018

Publication Type: Journal

Abstract (Expand)

Individual susceptibility to post-traumatic stress disorder (PTSD) is conditioned by genetic factors, and association between this disorder and polymorphisms of several genes have been shown. The aim of this study was to explore a potential association between single nucleotide polymorphisms (SNP) of the IL-1β gene (IL1B) and PTSD. In genomic DNA samples of PTSD-affected and healthy subjects, the rs16944, rs1143634, rs2853550, rs1143643, and rs1143633 SNPs of IL1B gene have been genotyped. The results obtained demonstrated that IL1B rs1143633*C and rs16944*A minor allele frequency were significantly lower in patients than in controls. Our results confirm that IL1B rs1143633 and rs16944 SNPs are negatively associated with PTSD which allows us to consider them as protective variants for PTSD. IL1B rs1143633*C and rs16944*A minor allele frequencies and carriage rates are significantly lower in the PTSD patients as compared to the controls. These results may provide a base to conclude that above-mentioned alleles can be protective against PTSD, and IL1B gene can be involved in the pathogenesis of this disorder.

Authors: Lilit Hovhannisyan, Ani Stepanyan, Arsen Arakelyan

Date Published: 5th Jul 2017

Publication Type: Journal

Abstract (Expand)

Cell signaling pathways are sequences of biochemical reactions that propagate an input signal, such as a hormone binding to a cell-surface receptor, into the cell to trigger a reactive process. Assessment of pathway activities is crucial for determining which pathways play roles in disease versus normal conditions. To date various pathway flow/perturbation assessment tools are available, however they are constrained to specific algorithms and specific data types. There are no accepted standards for evaluation of pathway activities or simulation of flow propagation events in pathways, and the results of different software are difficult to compare. Here we present Pathway Signal Flow Calculator (PSFC), a Cytoscape app for calculation of a pathway signal flow based on the pathway topology and node input data. The app provides a rich framework for customization of different signal flow algorithms to allow users to apply various approaches within a single computational framework.

Authors: L. Nersisyan, G. Johnson, M. Riel-Mehan, A. Pico, A. Arakelyan

Date Published: 25th Apr 2017

Publication Type: Journal

Abstract (Expand)

Background. Breast cancer is one of the most common cancers in women worldwide. The germline mutations of the BRCA1 and BRCA2 genes are the most significant and well characterized genetic risk factors for hereditary breast cancer. Intensive research in the last decades has demonstrated that the incidence of mutations varies widely among different populations. In this study we attempted to perform a pilot study for identification and characterization of mutations in BRCA1 and BRCA2 genes among Armenian patients with family history of breast cancer and their healthy relatives. Methods. We performed targeted exome sequencing for BRCA1 and BRCA2 genes in 6 patients and their healthy relatives. After alignment of short reads to the reference genome, germline single nucleotide variation and indel discovery was performed using GATK software. Functional implications of identified variants were assessed using ENSEMBL Variant Effect Predictor tool. Results. In total, 39 single nucleotide variations and 4 indels were identified, from which 15 SNPs and 3 indels were novel. No known pathogenic mutations were identified, but 2 SNPs causing missense amino acid mutations had significantly increased frequencies in the study group compared to the 1000 Genome populations. Conclusions. Our results demonstrate the importance of screening of BRCA1 and BRCA2 gene variants in the Armenian population in order to identity specifics of mutation spectrum and frequencies and enable accurate risk assessment of hereditary breast cancers. Keywords: BRCA1; BRCA2; breast cancer; mutation screening; targeted exome sequencing.

Authors: Sofi Atshemyan, Andranik Chavushyan, Nerses Berberian, Arthur Sahakyan, Roksana Zakharyan, Arsen Arakelyan

Date Published: 10th Jan 2017

Publication Type: Journal

Abstract (Expand)

Background: Schizophrenia (SCZ) is a multifactorial mental disease. Whereas complex interplay of genes and environment contributes to the SCZ, the disorder has still unclear biological background. Growing amount of evidence showed that synaptic dysfunctions are contributed to SCZ etiopathogenesis. The context and purpose of the study: Complexin-3, a presynaptic regulatory protein, represents here a special interest. This study was aimed to investigate the potential association of SCZ with rs3743487 single nucleotide polymorphism of the complexin-3 protein encoding gene (CPLX3). A total of 350 unrelated individuals of Armenian nationality (175 SCZ patients and the same number of age-, sex-matched healthy controls) were genotyped for the selected polymorphism using polymerase chain reaction with sequence-specific primers. Results and main findings: According to the results obtained, the frequency and carriage of the CPLX3 rs3743487*T allele did not differ in SCZ patients as compared to controls. Conclusions: We concluded that the CPLX3 rs3743487*T minor allele is not associated with SCZ in Armenian population. Brief summary: This study suggested no association of the CPLX3 rs3743487 polymorphism with schizophrenia, however, to clarify the role of the CPLX3 gene in SCZ further studies with much coverage of the gene and involvement of different methods are required.

Authors: Atshemyan Sofi, Zakharyan Roksana, Arakelyan Arsen

Date Published: 30th Dec 2015

Publication Type: Journal

Abstract (Expand)

We systematically studied the expression of more than fifty histone and DNA (de)methylating enzymes in lymphoma and healthy controls. As a main result, we found that the expression levels of nearly all enzymes become markedly disturbed in lymphoma, suggesting deregulation of large parts of the epigenetic machinery. We discuss the effect of DNA promoter methylation and of transcriptional activity in the context of mutated epigenetic modifiers such as EZH2 and MLL2. As another mechanism, we studied the coupling between the energy metabolism and epigenetics via metabolites that act as cofactors of JmjC-type demethylases. Our study results suggest that Burkitt's lymphoma and diffuse large B-cell Lymphoma differ by an imbalance of repressive and poised promoters, which is governed predominantly by the activity of methyltransferases and the underrepresentation of demethylases in this regulation. The data further suggest that coupling of epigenetics with the energy metabolism can also be an important factor in lymphomagenesis in the absence of direct mutations of genes in metabolic pathways. Understanding of epigenetic deregulation in lymphoma and possibly in cancers in general must go beyond simple schemes using only a few modes of regulation.

Authors: Lydia Hopp, Lilit Nersisyan, Henry Löffler-Wirth, Arsen Arakelyan, Hans Binder

Date Published: 21st Oct 2015

Publication Type: Journal

Abstract (Expand)

The KEGG pathway database is a widely accepted source for biomolecular pathway maps. In this paper we present the CyKEGGParser app ( http://apps.cytoscape.org/apps/cykeggparser) for Cytoscape 3 that allows manipulation with KEGG pathway maps. Along with basic functionalities for pathway retrieval, visualization and export in KGML and BioPAX formats, the app provides unique features for computer-assisted adjustment of inconsistencies in KEGG pathway KGML files and generation of tissue- and protein-protein interaction specific pathways. We demonstrate that using biological context-specific KEGG pathways created with CyKEGGParser makes systems biology analysis more sensitive and appropriate compared to original pathways.

Authors: L. Nersisyan, R. Samsonyan, A. Arakelyan

Date Published: 13th Nov 2014

Publication Type: Journal

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