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Mouse embryonic stem cells as a model genetic system to dissect and exploit the RNA interference machinery.

Conditional gene targeting is often a useful approach to elucidate the in vivo function of a gene. We use this approach to investigate the biological role of the RNA interference (RNAi) pathway in mammals. In addition, the RNAi machinery in mammalian cells can be exploited for gene knock-down experiments. In this chapter, we discuss the variety of experiments that can be performed using genetically engineered embryonic stem (ES) cells. ES cells provide a mammalian genetic system that is physiological, and tractable for mutagenesis and experimentation. This approach is economical and rapid, because it does not require production and breeding of genetically engineered mice.

Animals↗

Genomic approaches for reconstructing gene networks.

Functional knowledge of individual genes encoding components of the cell signaling, metabolic and regulatory pathways is crucial to our understanding of physiology and pathophysiology. A central challenge in functional genomics is the creation of a working map delineating how eukaryotic cells coordinate and govern patterns of gene expression. This coordination is often depicted as an intertwined network or circuit of genes that alternately activate and repress each other. Multiple bioinformatic and high-throughput experimental approaches exist to aid in the reconstruction of gene networks. Albeit far from being complete, the ability to recreate gene networks from experimental data facilitates the systematic dissection of cell function at the molecular and genetic level. In this review, several different genomic technologies are discussed, and example studies that are promoting new discoveries and hypotheses are detailed.

Cluster Analysis↗

Telencephalic embryonic subtractive sequences: a unique collection of neurodevelopmental genes.

The vertebrate telencephalon is composed of many architectonically and functionally distinct areas and structures, with billions of neurons that are precisely connected. This complexity is fine-tuned during development by numerous genes. To identify genes involved in the regulation of telencephalic development, a specific subset of differentially expressed genes was characterized. Here, we describe a set of cDNAs encoded by genes preferentially expressed during development of the mouse telencephalon that was identified through a functional genomics approach. Of 832 distinct transcripts found, 223 (27%) are known genes. Of the remaining, 228 (27%) correspond to expressed sequence tags of unknown function, 58 (7%) are homologs or orthologs of known genes, and 323 (39%) correspond to novel rare transcripts, including 48 (14%) new putative noncoding RNAs. As an example of this latter group of novel precursor transcripts of micro-RNAs, telencephalic embryonic subtractive sequence (TESS) 24.E3 was functionally characterized, and one of its targets was identified: the zinc finger transcription factor ZFP9. The TESS transcriptome has been annotated, mapped for chromosome loci, and arrayed for its gene expression profiles during neural development and differentiation (in Neuro2a and neural stem cells). Within this collection, 188 genes were also characterized on embryonic and postnatal tissue by in situ hybridization, demonstrating that most are specifically expressed in the embryonic CNS. The full information has been organized into a searchable database linked to other genomic resources, allowing easy access to those who are interested in the dissection of the molecular basis of telencephalic development.

Animals↗

Evolution of class III homeodomain-leucine zipper genes in streptophytes.

Land plants underwent tremendous evolutionary change following the divergence of the ancestral lineage from algal relatives. Several important developmental innovations appeared as the embryophyte clade diversified, leading to the appearance of new organs and tissue types. To understand how these changes came about, we need to identify the fundamental genetic developmental programs that are responsible for growth, patterning, and differentiation and describe how these programs were modified and elaborated through time to produce novel morphologies. Class III homeodomain-leucine zipper (class III HD-Zip) genes, identified in the model plant Arabidopsis thaliana, provide good candidates for basic land plant patterning genes. We show that these genes may have evolved in a common ancestor of land plants and their algal sister group and that the gene family has diversified as land plant lineages have diversified. Phylogenetic analysis, expression data from nonflowering lineages, and evidence from Arabidopsis and other flowering plants indicate that class III HD-Zip genes acquired new functions in sporophyte apical growth, vascular patterning and differentiation, and leaf development. Modification of expression patterns that accompanied diversification of class III HD-Zip genes likely played an important role in the evolution of land plant form.

Base Sequence↗

Predicting diagnostic gene biomarkers associated with immune infiltration in patients with diabetes.

Diabetes is a global public health problem with various complications, which can lead to disability and mortality. This study identified potential diagnostic markers for diabetes and explored the immunometabolic mechanisms in the pathological process. The gene expression of 17 diabetes cases and 16 normal controls were obtained from the Gene Expression Omnibus (GEO) database. The "limma" package was employed for screening differentially expressed genes (DEGs). Gene functions and enriched pathways of DEGs were analyzed via Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Candidate key genes were screened using the least absolute shrinkage and selection operator (LASSO) regression model and support vector machine recursive feature elimination (SVM-RFE) analysis. The diagnostic effectiveness of identified markers was further verified via the receiver operating characteristic (ROC) curve. The compositional patterns of immune cell infiltration and signaling pathway enrichment associated with key genes were explored via single sample Gene Set Enrichment Analysis (ssGSEA) and GSEA analysis, respectively. Possible miRNAs interacting with key genes were predicted via miRcode database. B2M, FTL, SH3BGRL3, and SOD2 were recognized as diagnostic markers for diabetes based on LASSO regression and the support vector machine recursive feature elimination (SVM-RFE) feature selection algorithm. Analysis of immune cell infiltration demonstrated that the four key genes were related to B cells, neutrophils, macrophages, and CD8+ T cells. The diagnostic value of B2M, FTL, and SOD2 for diabetes was higher than that of SH3BGRL3 according to the ROC curve. Validation experiments indicated that the mRNA expression of B2M and FTL was increased in liver tissues of diabetic mice. B2M and FTL can act as diagnostic markers for diabetes and contribute to new understandings of the disease's molecular mechanisms.

Humans↗

MiR-26a-5p/EZH2 Mediates Wnt2 Promoter Methylation to Regulate Trophoblast Dysfunction.

INTRODUCTION: Preeclampsia (PE) is a common complication of pregnancy, with a concomitant incidence rate of up to 10% among pregnant women worldwide. METHODS: In the current research, we explored the role and mechanism of miR-26a-5p in trophoblast function using CCK-8, colony formation assay, and flow cytometry. The interaction between miR-26a-5p and EZH2 was analyzed using a luciferase reporter assay. Methylationspecific PCR was performed to detect the methylation level of Wnt2 in HTR8 cells. RESULTS: Wnt2 and miR-26a-5p promoted the proliferation and inhibited the apoptosis in trophoblasts (P<0.05). The secretion of inflammatory cytokines was suppressed by Wnt2 and miR-26a-5p (P<0.05). EZH2 was identified as a regulatory target of miR-26a-5p using HTR8 cells and bioinformatic tools. miR-26a-5p inhibited expression through direct binding to EZH2. Importantly, miR- 26a-5p mediated DNA methylation of Wnt2 to regulate Wnt2 expression in HTR8 cells. DISCUSSION: This study elucidates a novel regulatory axis that alleviates trophoblast dysfunction by promoting proliferation and suppressing inflammation and apoptosis. The findings reveal that the miR-26a-5p/EZH2/Wnt2 pathway, potentially involving promoter methylation, is crucial for maintaining trophoblast function. This work identifies a promising therapeutic target for PE, although further in vivo validation is required to confirm its clinical potential. CONCLUSION: It was found that miR-26a-5p increased the expression of Wnt2 by downregulating EZH2. Moreover, miR-26a-5p/EZH2/Wnt2 promoted the proliferation and inhibited the inflammation and apoptosis in trophoblasts. This research provides insight into the role of miR-26a- 5p/EZH2/Wnt2 as a novel indicator for the prevention and treatment of PE.

MicroRNAs↗

RNA interference as a gene-specific approach for molecular medicine.

The discovery of RNA interference (RNAi) in eukaryotic cells has been the major recent breakthrough in molecular and cell biology. RNAi machineries exert biological functions in gene regulation, genome defense and chromatin architecture and dynamics. The potential of RNAi to silence any gene of interest in a highly specific and efficient manner via double-stranded RNA (dsRNA) has literally revolutionized modern genetics. RNAi-based functional genomics now permits, for the first time, to evaluate the cellular role of individual gene products on a genome-wide scale in higher organisms like mammals, presenting an alternative to the generation of animal knockouts often doomed to failure because of a lethal phenotype. RNAi has had an enormous impact on the development of novel disease models in animals, and it is likely that small interfering RNAs (siRNAs), which are the trigger molecules for RNA silencing, will become an invaluable tool for the treatment of genetic diseases. First clinical trials, using siRNAs directed against the vascular endothelial growth factor (VEGF) or one of its receptors, have been initiated recently for the treatment of age-related macular degeneration. Improving guidelines for the rational design of siRNAs, based on recent progress in understanding the mechanisms underlying RNAi, as well as the introduction of chemical modifications into siRNAs are expected to improve their pharmacokinetic and pharmacodynamic properties for in vivo applications. Finally, successful therapeutic application of RNAi will depend on the development of improved siRNA delivery strategies that combine high specificity and efficiency with a low immunostimulatory and tumorigenic potential.

Chemistry, Pharmaceutical↗

Radiation-induced response of micro RNA expression in murine embryonic stem cells.

Despite the importance of embryonic stem cells in embryology and regenerative medicine, their response to DNA damage is not fully understood. Here we studied the expression profiles of small RNAs approximately 22 nucleotides long called micro RNAs, which play an important role in developmental regulation in plants and animals. We identified a group of micro RNAs with increased expression after exposure to radiation (compared with murine fibroblasts) and characterized putative target genes. These micro RNA sequences are conserved in mice, chickens and humans with similar genomic organizations, suggesting that a common regulatory network is involved in stem cell regulation in response to DNA damage. Micro RNAs might be useful as therapeutic tools to control DNA damage response in pluripotent stem cells.

Animals↗

Co-expression of the Mammaglobin (SCGB2A2) Gene With hsa-miR-184 and hsa-miR-190b Indicates Its Possible Role in Oncogenic Pathways in Breast Cancer.

BACKGROUND/AIM: Breast cancer is the most common cancer in women worldwide, and early detection remains a significant challenge. Recent studies have identified increased expression of Mammaglobin A (Q13296, Gene: SCGB2A2) mRNA in breast cancer, suggesting its potential as a disease marker, although its function is not fully understood. To elucidate Mammaglobin's role, this study sought to identify co-expressed miRNAs and analyze the biological pathways they regulate. MATERIALS AND METHODS: Using TCGAbiolinks and Firebrowse, miRNA and gene expression data were collected from 86 patients, including tumor and normal tissue samples from the Cancer Genome Atlas (TCGA) Breast Cancer cohort. Transcriptomic data were analyzed with DESeq2, and a Spearman correlation was calculated for significant p-values, which were further explored using enrichment tools and target gene databases. RESULTS: DESeq2 was used to identify differential expression of miRNAs between normal and tumor breast tissues. Out of 782 miRNAs differentially expressed in breast cancer, hsa-mir-184 and hsa-mir-190b showed a significant positive correlation with SCGB2A expression. These markers were also upregulated in breast cancer tissues compared to normal tissues. Bioinformatics analysis revealed that hsa-mir-184 and hsa-mir-190b play important roles in cancer and cellular proliferation. These miRNAs target a wide range of genes, including sorting nexin 9 (SNX9) and annexin 6 (ANXA6), which are involved in membrane stability, vesicular trafficking, and cell mobility, and they contribute to cancer metastasis. CONCLUSION: The positive correlation among the expression of hsa-miR-184, hsa-miR-190b, and SCGB2A2 suggests that they may participate in shared biological pathways. These pathways govern critical cellular processes, such as membrane trafficking and cell signaling, which are frequently disrupted in cancer. Consequently, these findings enable a better understanding of the role of Mammaglobin in breast cancer signaling.

MicroRNAs (miRNAs)↗

Microarray tools for deciphering complex diseases.

Individual genetic findings associated with complex diseases are unlikely to fully explain their substantial impact or provide new comprehensive insights into disease pathogenesis. These also lack the comprehensive data much needed for development of new effective drugs in majority of the disease cases in a population. In fact multilevel etiologic factors underlie almost all human diseases, including: environmental causes, epigenetic factors, DNA mutations, amplifications, and deletions, RNA expression levels, protein (translation, post translation modification, localization) and combinations thereof. Each individual might consist of different combinations of these multiple etiologic factors. Integrative evaluation of all these modifications will shed light on the whole identity of the disease and the underlying molecular mechanisms. Until now it was inconceivable to have a full grasp of such a complex etiology. Microarrays enable us to interrogate the individualized various factors (DNA, RNA and protein content) involved in disease state on genome-wide scale simultaneously and expeditiously in single cell or the tissue of interest (Figure 1). The new disciplines of microarray studies in combination hold the promise of effective, current, and comprehensive understanding of complex diseases and may be a good approach for reducing the costs and time lines associated with discovery and efficacy improvement of therapeutic drugs. In the future, through utilizing the colossal amount of microarray data findings, defining the structure, function, and dynamics of entire biological pathways and cellular networks under various physiological states, and the development of robust and efficient methods for analyzing and interpreting high dimensional data, it will be possible to connect combination of experimental results with individualized disease state. This will facilitate precise diagnosis prognosis and therapy.

Alternative Splicing↗

Interconnected study of molecular pathways: miR-137 as a central element at the intersection of lipid metabolism and prostate carcinogenesis.

OBJECTIVE: To evaluate the roles of miR-137 and its target genes in lipid metabolism and prostate tumorigenesis. METHODS: We used a series of bioinformatic approaches to establish the relationship between miR-137 and its target genes. We mapped the metabolic pathways of interest in the Reactome database and identified the central target genes of miR-137 in this pathway using four platforms: Reactome, miRDB, miRmap, and TargetScan. To assess the expression and association with clinical parameters, we obtained information from the UALCAN, OncoDB, and GEPIA2 databases using a dataset of patients with prostate cancer from The Cancer Genome Atlas. For functional enrichment analysis and construction of the protein-protein interaction network, we used the Kyoto Encyclopedia of Genes and Genomes, Gene Ontology, and STRING. RESULTS: Our in silico study of The Cancer Genome Atlas database revealed that miR-137 is underexpressed in tumor tissues, and its reduction is associated with poor prognosis. An intriguing set of eight genes within the PPAR&#x3b1; pathway: PPARGC1A, PPARGC1B, NCOA1, NCOA2, NCOA3, MED1, MED27, and ESRRA displayed synergy, positive correlations, and synchronized expression patterns in adipose, hepatic, and prostatic tissues, all linked to the enigmatic processes of metabolic regulation. Among the highlighted genes, ESRRA was overexpressed in the malignant environment, whereas its counterparts remained underexpressed. The plot was thickened with associations between the expression of NCOA1, NCOA3, and MED27, lymph node involvement, and the overexpression of several genes linked to advanced prostate cancer stages. An intriguing pattern emerged, with patients exhibiting reduced disease-free survival overexpressing NCOA2, NCOA3, MED27, and ESRRA. CONCLUSION: This study elucidates the possibility that miR-137 subtly modulates metabolic genes in prostate cancer, suggesting its latent therapeutic potential as a biomarker for disease progression. BACKGROUND: &#x25a0; The reduction of miR-137 in tumor tissues is associated with a worse prognosis. BACKGROUND: &#x25a0; miR-137 has eight oncogenically relevant target genes acting in the PPAR&#x3b1; lipid pathway. BACKGROUND: &#x25a0; NCOA1, NCOA3, MED27, and ESRRA are associated with advanced prostate cancer. BACKGROUND: &#x25a0; miR-137 exhibits significant clinical potential by repressing the activation of pathways that influence prostate tumorigenesis in hyperstimulated metabolic environments. BACKGROUND: Prostate cancer progression is sustained by the simultaneous activation of pathways involving lipid uptake and de novo synthesis. In this context, miR-137 inhibits adipogenic differentiation and may reduce lipid uptake by tumor cells by modulating the PPAR/ p160/ESRRA axis, considerably attenuating metabolic effects and suppressing prostate tumorigenesis.

Male↗

IL1B-centered immune dysregulation involving IL7R, CCR7, ITGB2 and IRF1 across insomnia and inflammatory bowel disease.

BACKGROUND: Insomnia is a prevalent sleep disorder that strongly affects one's quality of life and physical well-being. Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the intestines, and a majority of IBD patients suffer from comorbid insomnia. However, the shared molecular features linking insomnia and IBD remain poorly characterized. METHODS: Common differentially expressed genes (DEGs) were identified in datasets of insomnia (GSE208668) and IBD (GSE179285) using the Limma package. Functional enrichment was performed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. Protein-protein interaction (PPI) network construction and hub gene identification was subsequently performed. Furthermore, we validated the reliability of the hub genes using qRT-PCR and Enzyme-linked immunosorbent assay (ELISA). In addition, we constructed a TF-miRNA regulatory network of hub genes and assessed the abundance of immune cell infiltration in insomnia and IBD using CIBERSORT, EPIC, and xCell algorithms. Finally, we utilized the DsigDB to predict potential therapeutic candidates. RESULTS: The analysis revealed 75 upregulated and 32 downregulated common DEGs. Functional enrichment analysis revealed the inflammatory response and immune activation as pivotal drivers underlying the pathogenesis of both insomnia and IBD. Five hub DEGs, namely, IL1B, IL7R, CCR7, ITGB2, and IRF1, were subsequently screened and validated. The TF-miRNA-mRNA regulatory network consisted of 5 TFs, 14 miRNA nodes and 5 core mRNA nodes. Immune cell infiltration analysis revealed several patterns shared between insomnia and IBD. Additionally, 10 potential therapeutic drugs for insomnia and IBD were proposed. CONCLUSION: Integrative coexpression network analysis reveals convergent dysregulation of an IL1B-centered immune module (comprising IL7R, CCR7, ITGB2, and IRF1) across insomnia and IBD, a shared immune disturbance and candidate targets for simultaneous intervention upon further mechanistic validation.

Humans↗

An Exosomal miRNA Biomarker for the Detection of Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) remains a difficult tumor to diagnose and treat. To date, PDAC lacks routine screening with no markers available for early detection. Exosomes are 40-150 nm-sized extracellular vesicles that contain DNA, RNA, and proteins. These exosomes are released by all cell types into circulation and thus can be harvested from patient body fluids, thereby facilitating a non-invasive method for PDAC detection. A bioinformatics analysis was conducted utilizing publicly available miRNA pancreatic cancer expression and genome databases. Through this analysis, we identified 18 miRNA with strong potential for PDAC detection. From this analysis, 10 (MIR31, MIR93, MIR133A1, MIR210, MIR330, MIR339, MIR425, MIR429, MIR1208, and MIR3620) were chosen due to high copy number variation as well as their potential to differentiate patients with chronic pancreatitis, neoplasms, and PDAC. These 10 were examined for their mature miRNA expression patterns, giving rise to 18 mature miRs for further analysis. Exosomal RNA from cell culture media was analyzed via RTqPCR and seven mature miRs exhibited statistical significance (miR-31-5p, miR-31-3p, miR-210-3p, miR-339-5p, miR-425-5p, miR-425-3p, and miR-429). These identified biomarkers can potentially be used for early detection of PDAC.

Humans↗

A Comparative Analysis of the Methylation Status of Non-Coding RNA Promoters in Fibroid and Matched Myometrium.

Uterine fibroids exhibit dysregulated expression of non-coding RNAs (ncRNAs), although the underlying mechanisms remain incompletely understood. We investigated promoter DNA methylation and its relationship with ncRNA expression in fibroids. Genomic DNA from eight paired fibroid and matched myometrial tissues was analyzed using MeDIP-chip to identify differentially methylated ncRNA promoters. Selected candidates were validated by methylation-specific PCR (MSP) in 16 paired samples, and transcript expression was assessed by qRT-PCR in 68-94 paired specimens. MeDIP-chip identified 538 lncRNAs and 61 miRNAs with differential promoter methylation, including 300 hypermethylated and 238 hypomethylated lncRNAs and 47 hypermethylated and 14 hypomethylated miRNAs. Promoter methylation was not significantly correlated with transcript expression (r = -0.1224). MSP confirmed hypermethylation of LINC-PINT and MIR9-3 and hypomethylation of WT1-AS and TTLL10-AS1. Correspondingly, LINC-PINT and MIR9-3 expression was decreased, whereas WT1-AS and TTLL10-AS1 expression was increased in fibroids. However, LINC-PINT and TTLL10-AS1 methylation did not fully correspond with MeDIP-chip findings. These results reveal widespread ncRNA promoter methylation alterations in uterine fibroids but demonstrate that genome-wide methylation does not consistently predict transcript expression, highlighting the complexity of ncRNA epigenetic regulation and the importance of locus-specific validation.

Humans↗

A small yeast RNA inhibits HCV IRES mediated translation and inhibits replication of poliovirus in vivo.

AIM: To investigate the anti-virus infection activity of internal ribosome entry site (IRES) specific inhibitor RNA (IRNA). METHODS: IRNA eukaryotic vector pcRz-IRNA or mIRNA eukaryotic vector pcRz-mIRNA was transfected into human hepatocarcinoma cells (HHCC), then selected with neomycin G418 for 4 to 8 weeks, and then infected with polio virus vaccines line. The cytopethogenesis effect was investigated and the cell extract was collected. At last the polio virus titer of different cells was determined by plaque assay. RESULTS: Constructive expression of IRNA was not detrimental to cell growth. HCV IRES-mediated cap-independent translation was markedly inhibited in cells constructively expressing IRNA compared to control hepatoma cells. However, cap-dependent translation was not significantly affected in these cell line. Additionally, HHCC cells constitutively expressing IRNA became refractory to infection of polio virus. CONCLUSION: IRES specific IRNA can inhibit HCV IRES mediated translation and poliovirus replication.

5' Untranslated Regions↗

miR-197 Targets NLRP3 3' UTR and Correlates with NLRP3/Caspase-1/IL-18 Signaling in Hyperoxia-Stimulated Neonatal BPD Mouse Model.

Reduced circulating miR-197 was previously observed in preterm infants who later developed bronchopulmonary dysplasia (BPD), but its relationship with NLRP3 inflammasome signaling remains unclear. This study examined miR-197 expression, NLRP3 inflammasome-related markers, and the interaction between miR-197 and the NLRP3 3' UTR in a neonatal hyperoxia model. Neonatal C57BL/6J mice were exposed to 60% oxygen or room air from birth, and lung tissues were collected on postnatal days 1, 7, 14, and 21. Lung injury and alveolar development were assessed by histology, radial alveolar count, mean linear intercept, and lung wet-to-dry ratio. miR-197 and NLRP3 expression and NF-&#x3ba;B-, caspase-1-, and IL-18-related proteins were evaluated by RT-qPCR and Western blotting. A dual-luciferase reporter assay in MLE12 cells tested the interaction between miR-197 and the NLRP3 3' UTR. Hyperoxia increased lung wet-to-dry ratios and mean linear intercept, reduced radial alveolar count, and caused progressive alveolar simplification. miR-197 expression decreased, whereas NLRP3 mRNA increased, at all examined time points; NLRP3 protein and inflammasome-related protein changes were most evident from postnatal day 7 onward. The miR-197 mimic reduced luciferase activity in the wild-type but not mutant NLRP3 3' UTR reporter. These findings show that neonatal hyperoxia is associated with reduced miR-197 and increased NLRP3/inflammasome-related signaling and support a sequence-specific interaction between miR-197 and the NLRP3 3' UTR, although causal regulation in vivo requires further investigation.

Animals↗