scholarly journals The impact of methodology on the reproducibility and rigor of DNA methylation data

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Detlev Boison ◽  
Susan A. Masino ◽  
Farah D. Lubin ◽  
Kai Guo ◽  
Theresa Lusardi ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Outcome Measures ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Data Interpretation ◽  
Research Area ◽  
Wild Type ◽  
Strict Adherence ◽  
Baseline Conditions ◽  
The Impact

AbstractEpigenetic modifications are crucial for normal development and implicated in disease pathogenesis. While epigenetics continues to be a burgeoning research area in neuroscience, unaddressed issues related to data reproducibility across laboratories remain. Separating meaningful experimental changes from background variability is a challenge in epigenomic studies. Here we show that seemingly minor experimental variations, even under normal baseline conditions, can have a significant impact on epigenome outcome measures and data interpretation. We examined genome-wide DNA methylation and gene expression profiles of hippocampal tissues from wild-type rats housed in three independent laboratories using nearly identical conditions. Reduced-representation bisulfite sequencing and RNA-seq respectively identified 3852 differentially methylated and 1075 differentially expressed genes between laboratories, even in the absence of experimental intervention. Difficult-to-match factors such as animal vendors and a subset of husbandry and tissue extraction procedures produced quantifiable variations between wild-type animals across the three laboratories. Our study demonstrates that seemingly minor experimental variations, even under normal baseline conditions, can have a significant impact on epigenome outcome measures and data interpretation. This is particularly meaningful for neurological studies in animal models, in which baseline parameters between experimental groups are difficult to control. To enhance scientific rigor, we conclude that strict adherence to protocols is necessary for the execution and interpretation of epigenetic studies and that protocol-sensitive epigenetic changes, amongst naive animals, may confound experimental results.

scholarly journals Age-related differences in monocyte DNA methylation and immune function in healthy Kenyan adults and children

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Katherine R. Dobbs ◽  
Paula Embury ◽  
Emmily Koech ◽  
Sidney Ogolla ◽  
Stephen Munga ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Young Adults ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Innate Immune ◽  
Inflammatory Gene Expression ◽  
Cpg Sites ◽  
Age Related ◽  
Adults And Children

Abstract Background Age-related changes in adaptive and innate immune cells have been associated with a decline in effective immunity and chronic, low-grade inflammation. Epigenetic, transcriptional, and functional changes in monocytes occur with aging, though most studies to date have focused on differences between young adults and the elderly in populations with European ancestry; few data exist regarding changes that occur in circulating monocytes during the first few decades of life or in African populations. We analyzed DNA methylation profiles, cytokine production, and inflammatory gene expression profiles in monocytes from young adults and children from western Kenya. Results We identified several hypo- and hyper-methylated CpG sites in monocytes from Kenyan young adults vs. children that replicated findings in the current literature of differential DNA methylation in monocytes from elderly persons vs. young adults across diverse populations. Differentially methylated CpG sites were also noted in gene regions important to inflammation and innate immune responses. Monocytes from Kenyan young adults vs. children displayed increased production of IL-8, IL-10, and IL-12p70 in response to TLR4 and TLR2/1 stimulation as well as distinct inflammatory gene expression profiles. Conclusions These findings complement previous reports of age-related methylation changes in isolated monocytes and provide novel insights into the role of age-associated changes in innate immune functions.

scholarly journals Integrated Genomic Analysis of Sézary Syndrome

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
Xin Mao ◽  
Tracy Chaplin ◽  
Bryan D. Young
Keyword(s):  
Copy Number ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Genomic Analysis ◽  
Gene Clusters ◽  
Sézary Syndrome ◽  
Sezary Syndrome ◽  
Snp Microarray ◽  
The Impact ◽  
Chromosome Regions

Sézary syndrome (SS) is a rare variant of primary cutaneous T-cell lymphoma. Little is known about the underlying pathogenesis of S. To address this issue, we used Affymetrix 10K SNP microarray to analyse 13 DNA samples isolated from 8 SS patients and qPCR with ABI TaqMan SNP genotyping assays for the validation of the SNP microarray results. In addition, we tested the impact of SNP loss of heterozygosity (LOH) identified in SS cases on the gene expression profiles of SS cases detected with Affymetrix GeneChip U133A. The results showed: (1) frequent SNP copy number change and LOH involving 1, 2p, 3, 4q, 5q, 6, 7p, 8, 9, 10, 11, 12q, 13, 14, 16q, 17, and 20, (2) reduced SNP copy number at FAT gene (4q35) in 75% of SS cases, and (3) the separation of all SS cases from normal control samples by SNP LOH gene clusters at chromosome regions of 9q31q34, 10p11q26, and 13q11q12. These findings provide some intriguing information for our current understanding of the molecular pathogenesis of this tumour and suggest the possibility of presence of functional SNP LOH in SS tumour cells.

Transduction of mouse retina by insect cell packaged recombinant adeno-associated virusess and their mutants via intravitreal injection

2021 ◽  
Author(s):  
Zheng Wei ◽  
Xiaomei Liu ◽  
Taiming Li ◽  
Xiaofang Li ◽  
Qungang Zhou ◽  
...  
Keyword(s):  
Gene Expression ◽  
Expression Profiles ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Gene Expression Profiles ◽  
Mouse Retina ◽  
Transduction Efficiency ◽  
Egfp Expression ◽  
Wild Type ◽  
Gene Therapy Vector

Aim: Adeno-associated virus (AAV) is the most preferred gene therapy vector. The purpose of our research is to compare the infection tropism and gene expression efficiency of vitreous injection of recombinant AAVs (rAAVs) and their capsid mutants in mouse retina. Materials & methods: We packaged wild-type rAAV2/2,6,8,9 and their capsid mutants carrying EGFP expression cassette using insect cells. The gene expression profiles of rAAVs and their mutants in mouse retina were evaluated by optical imaging of retinal tissue flat mount and cryosections. Results & conclusion: The results showed that rAAV2 and rAAV2-Y444F mainly targeted retinal ganglion cell; rAAV8, rAAV8-Y733F, rAAV9 and mutants had obvious EGFP expression in retinal pigment epithelium cells. Compared with the wild-type rAAVs, capsid mutants have an improved transduction efficiency in mouse retina cells.

scholarly journals Transcriptomic Modification in the Cerebral Cortex following Noninvasive Brain Stimulation: RNA-Sequencing Approach

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Ben Holmes ◽  
Seung Ho Jung ◽  
Jing Lu ◽  
Jessica A. Wagner ◽  
Liudmilla Rubbi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cerebral Cortex ◽  
Rna Sequencing ◽  
Molecular Mechanisms ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Current Intensity ◽  
Beneficial Effects ◽  
Group A ◽  
The Impact

Transcranial direct current stimulation (tDCS) has been shown to modulate neuroplasticity. Beneficial effects are observed in patients with psychiatric disorders and enhancement of brain performance in healthy individuals has been observed following tDCS. However, few studies have attempted to elucidate the underlying molecular mechanisms of tDCS in the brain. This study was conducted to assess the impact of tDCS on gene expression within the rat cerebral cortex. Anodal tDCS was applied at 3 different intensities followed by RNA-sequencing and analysis. In each current intensity, approximately 1,000 genes demonstrated statistically significant differences compared to the sham group. A variety of functional pathways, biological processes, and molecular categories were found to be modified by tDCS. The impact of tDCS on gene expression was dependent on current intensity. Results show that inflammatory pathways, antidepressant-related pathways (GTP signaling, calcium ion binding, and transmembrane/signal peptide pathways), and receptor signaling pathways (serotonergic, adrenergic, GABAergic, dopaminergic, and glutamate) were most affected. Of the gene expression profiles induced by tDCS, some changes were observed across multiple current intensities while other changes were unique to a single stimulation intensity. This study demonstrates that tDCS can modify the expression profile of various genes in the cerebral cortex and that these tDCS-induced alterations are dependent on the current intensity applied.

scholarly journals An Evolutionary Method for Combining Different Feature Selection Criteria in Microarray Data Classification

2009 ◽  
Vol 2009 ◽  
pp. 1-10 ◽  
Author(s):  
Nicoletta Dessì ◽  
Barbara Pes
Keyword(s):  
Microarray Data ◽  
Selection Criteria ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Research Area ◽  
Svm Classifier ◽  
Ranking Methods ◽  
Wrapper Approach ◽  
Relevant Gene

The classification of cancers from gene expression profiles is a challenging research area in bioinformatics since the high dimensionality of microarray data results in irrelevant and redundant information that affects the performance of classification. This paper proposes using an evolutionary algorithm to select relevant gene subsets in order to further use them for the classification task. This is achieved by combining valuable results from different feature ranking methods into feature pools whose dimensionality is reduced by a wrapper approach involving a genetic algorithm and SVM classifier. Specifically, the GA explores the space defined by each feature pool looking for solutions that balance the size of the feature subsets and their classification accuracy. Experiments demonstrate that the proposed method provide good results in comparison to different state of art methods for the classification of microarray data.

scholarly journals Identification of Prognostic Markers in Cholangiocarcinoma Using Altered DNA Methylation and Gene Expression Profiles

2020 ◽  
Vol 11 ◽  
Author(s):  
Nitish Kumar Mishra ◽  
Meng Niu ◽  
Siddesh Southekal ◽  
Prachi Bajpai ◽  
Amr Elkholy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Prognostic Markers ◽  
Expression Profiles ◽  
Gene Expression Profiles

scholarly journals RNAseq Studies Reveal Distinct Transcriptional Response to Vitamin a (VA) Deficiency in Small Intestine (SI) versus Colon, Discovering Novel VA-regulated Genes (P15-002-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
Zhi Chai ◽  
Yafei Lyu ◽  
Qiuyan Chen ◽  
Cheng-Hsin Wei ◽  
Lindsay Snyder ◽  
...  
Keyword(s):  
Gene Expression ◽  
Small Intestine ◽  
Vitamin A ◽  
Target Genes ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Differentially Expressed Gene ◽  
Gene Expression Profiles ◽  
Illumina Hiseq ◽  
The Impact

Abstract Objectives To characterize and compare the impact of vitamin A (VA) deficiency on gene expression patterns in the small intestine (SI) and the colon, and to discover novel target genes in VA-related biological pathways. Methods vitamin A deficient (VAD) mice were generated by feeding VAD diet to pregnant C57/BL6 dams and their post-weaning offspring. Total mRNA extracted from SI and colon were sequenced using Illumina HiSeq 2500 platform. Differentially Expressed Gene (DEG), Gene Ontology (GO) enrichment, and Weighted Gene Co-expression Network Analysis (WGCNA) were performed to characterize expression patterns and co-expression patterns. Results The comparison between vitamin A sufficient (VAS) and VAD groups detected 49 and 94 DEGs in SI and colon, respectively. According to GO information, DEGs in the SI demonstrated significant enrichment in categories relevant to retinoid metabolic process, molecule binding, and immune function. Immunity related pathways, such as “humoral immune response” and “complement activation,” were positively associated with VA in SI. On the contrary, in colon, “cell division” was the only enriched category and was negatively associated with VA. WGCNA identified modules significantly correlated with VA status in SI and in colon. One of those modules contained five known retinoic acid targets. Therefore we have prioritized the other module members (e.g., Mbl2, Mmp9, Mmp13, Cxcl14 and Pkd1l2) to be investigated as candidate genes regulated by VA. Comparison of co-expression modules between SI and colon indicated distinct VA effects on these two organs. Conclusions The results show that VA deficiency alters the gene expression profiles in SI and colon quite differently. Some immune-related genes (Mbl2, Mmp9, Mmp13, Cxcl14 and Pkd1l2) may be novel targets under the control of VA in SI. Funding Sources NIH training grant and NIH research grant. Supporting Tables, Images and/or Graphs

P4-124: Comparison of gene expression profiles of prion protein-deficient and wild type neuronal cell lines of mice

2006 ◽  
Vol 2 ◽  
pp. S552-S552
Author(s):  
Boe-Hyun Kim ◽  
Jae-Il Kim ◽  
Eun-Kyoung Choi ◽  
Richard I. Carp ◽  
Yong-Sun Kim
Keyword(s):  
Gene Expression ◽  
Prion Protein ◽  
Cell Lines ◽  
Expression Profiles ◽  
Neuronal Cell ◽  
Gene Expression Profiles ◽  
Wild Type ◽  
Neuronal Cell Lines

Gene Expression Profiles of Early Implant Adherent Cells in Smokers and Nonsmokers

2015 ◽  
Vol 41 (6) ◽  
pp. 640-645 ◽  
Author(s):  
Ghadeer Thalji ◽  
Lyndon F. Cooper ◽  
Salvador Nares
Keyword(s):  
Gene Expression ◽  
Early Stage ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Whole Genome ◽  
Adherent Cells ◽  
Mini Implants ◽  
Molecular Events ◽  
The Impact

The objective of this study was to evaluate the impact of smoking on the early molecular events involved in peri-implant healing at either a micro-roughened or a micro-roughened with superimposed nanofeatures surface implant in humans. Twenty-one subjects, 10 smokers and 11 nonsmokers received 4 mini-implants (2.2 × 5.0 mm; 2 of each surface). After 3 and 7 days, paired mini-implants were retrieved by reverse threading and RNA isolated from implant adherent cells. Whole genome microarrays were used interrogate the gene expression profiles. The study failed to identify differences in the gene expression profiles of implant adherent cells at this early stage of osseointegration (up to day 7) comparing smoker and nonsmoker individuals.

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