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Screening of the key single nucleotide polymorphisms in type 2 diabetes mellitus complicated with lower extremity arterial disease by machine learning.

OBJECTIVES: Diabetic lower extremity arterial disease (LEAD) is a manifestation of diabetic lower extremity vascular complications. This study aimed to screen the key single nucleotide polymorphism (SNP) gene signature in patients with type 2 diabetes mellitus (T2DM) and LEAD. METHODS: A total of 147 patients with T2DM complicated by LEAD and 144 patients with T2DM without LEAD were enrolled for transcriptome sequencing. The Plink software was used to preprocess the data. Five machine learning methods were adopted to build the SNP diagnosis models. The receiver operating characteristic (ROC) curve was used to quantify the predicted probabilities of the model. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed using the cluster Profiler package. Finally, regression statistical analysis was used to correlate the key SNPs with clinical information and biochemical indicators. RESULTS: A total of 24 SNPs were retained and 10 SNPs were risk allele genes. Nine SNPs (rs7412, rs1800629, rs699947, rs3918242, rs668, rs1800470, rs1800449, rs1800469, and rs1024611) were identified as the key SNPs sites. GO and KEGG pathway analyses revealed that these genes are mainly enriched in fluid shear stress and atherosclerosis. Finally, rs1800449 was associated with low-density lipoprotein cholesterol (LDL-C). With high density lipoprotein cholesterol (HDL-C), related site was rs1024611. The sites associated with total cholesterol (CHOL) were rs1800449 and rs7412.The site associated with apolipoprotein B (APOB) and apolipoprotein A1 (APOA1) were rs1800470 and rs1800469. CONCLUSION: This study authenticated nine SNPs for the diagnosis of T2DM patients with LEAD, which will be of great significance in the development of diagnostic molecular biomarkers for T2DM patients.

Humans↗

When defense pathways collide. The response of Arabidopsis to a combination of drought and heat stress.

Within their natural habitat, plants are subjected to a combination of abiotic conditions that include stresses such as drought and heat. Drought and heat stress have been extensively studied; however, little is known about how their combination impacts plants. The response of Arabidopsis plants to a combination of drought and heat stress was found to be distinct from that of plants subjected to drought or heat stress. Transcriptome analysis of Arabidopsis plants subjected to a combination of drought and heat stress revealed a new pattern of defense response in plants that includes a partial combination of two multigene defense pathways (i.e. drought and heat stress), as well as 454 transcripts that are specifically expressed in plants during a combination of drought and heat stress. Metabolic profiling of plants subjected to drought, heat stress, or a combination of drought and heat stress revealed that plants subject to a combination of drought and heat stress accumulated sucrose and other sugars such as maltose and glucose. In contrast, Pro that accumulated in plants subjected to drought did not accumulate in plants during a combination of drought and heat stress. Heat stress was found to ameliorate the toxicity of Pro to cells, suggesting that during a combination of drought and heat stress sucrose replaces Pro in plants as the major osmoprotectant. Our results highlight the plasticity of the plant genome and demonstrate its ability to respond to complex environmental conditions that occur in the field.

Acclimatization↗

Transcriptomic analyses support the similarity of gene expression between brain and testis in human as well as mouse.

We previously revealed similarity in gene expression patterns between human brain and testis, based on digital differential display analyses of 760 human Unigenes. In the present work, we reanalyzed the gene expression data in many tissues of human and mouse for a large number of genes almost covering the respective whole genomes. The results indicated that both in human and in mouse, the gene expression profiles exhibited by brain, cerebellum and testis are most similar to each other compared with other tissues.

Animals↗

Mutant SOD1 alters the motor neuronal transcriptome: implications for familial ALS.

Familial amyotrophic lateral sclerosis (FALS) is caused, in 20% of cases, by mutations in the Cu/Zn superoxide dismutase gene (SOD1). Although motor neuron injury occurs through a toxic gain of function, the precise mechanism(s) remains unclear. Using an established NSC34 cellular model for SOD1-associated FALS, we investigated the effects of mutant SOD1 specifically in cells modelling the vulnerable cell population, the motor neurons, without contamination from non-neuronal cells present in CNS. Using gene expression profiling, 268 transcripts were differentially expressed in the presence of mutant human G93A SOD1. Of these, 197 were decreased, demonstrating that the presence of mutant SOD1 leads to a marked degree of transcriptional repression. Amongst these were a group of antioxidant response element (ARE) genes encoding phase II detoxifying enzymes and antioxidant response proteins (so-called 'programmed cell life' genes), the expression of which is regulated by the transcription factor NRF2. We provide evidence that dysregulation of Nrf2 and the ARE, coupled with reduced pentose phosphate pathway activity and decreased generation of NADPH, represent significant and hitherto unrecognized components of the toxic gain of function of mutant SOD1. Other genes of interest significantly altered in the presence of mutant SOD1 include several previously implicated in neurodegeneration, as well as genes involved in protein degradation, the immune response, cell death/survival and the heat shock response. Preliminary studies on isolated motor neurons from SOD1-associated motor neuron disease cases suggest key genes are also differently expressed in the human disease.

Amyotrophic Lateral Sclerosis↗

Integrative analysis and experiment validation of SLC12A8 as a biomarker for the malignant transition from endometriosis to endometriosis associated ovarian cancer.

Endometriosis (EM) is a chronic inflammatory, estrogen‑dependent benign gynecological disorder. A subset of patients with EM may subsequently develop endometriosis‑associated ovarian cancer (EAOC), implying a biological continuum between these two conditions. Nevertheless, the molecular events underlying the progression from benign endometriotic lesions toward EAOC remain incompletely characterized. In this study, transcriptomic datasets retrieved from the GEO database were interrogated through differentially expressed gene screening, functional enrichment analysis, and weighted gene co‑expression network analysis (WGCNA) to identify key genes and pathways relevant to EM and EAOC. Candidate genes were further prioritized by integrating survival analysis via the Kaplan‑Meier Plotter, LASSO regression, random‑forest modeling, and CIBERSORT immune‑infiltration profiling. Loss and gain‑of‑function cellular models were established using siRNA and overexpression plasmids, and in‑vitro functional assays were performed to characterize the phenotypic effects of target genes.We identified several candidate genes associated with EM and EAOC and evaluated their discriminatory performance. Among them, SLC12A8 elevated expression across EM and EAOC tissues and exhibited moderate diagnostic capacity. Higher SLC12A8 expression was also associated with poorer prognosis in EAOC patients. In‑vitro experiments further demonstrated that SLC12A8 modulates proliferation, invasion, and migration in both EM and EAOC cell lines. Collectively, our exploratory research findings support SLC12A8 as a candidate functional mediator and potential biomarker linked to EM‑EAOC pathological progression, thereby extending the mechanistic understanding of these disorders.

Female↗

Integrated RNA-seq and RNAi analyses reveal that ABCF2 is involved in defense against Vibrio parahaemolyticus in Penaeus vannamei.

The sustainable development of shrimp aquaculture is significantly compromised by Vibrio parahaemolyticus infections. Identifying host resistance genes and characterizing their immunological roles are essential for developing effective disease control strategies. In this study, we conducted a comparative transcriptomic analysis of intestinal tissues from Penaeus vannamei exhibiting varying degrees of pathological damage post-V. parahaemolyticus challenge to identify key resistance genes. KEGG enrichment analysis revealed that the ABC transporter pathway was markedly enriched among upregulated genes in both the 9 h vs 0 h and 48 h vs 0 h comparison groups. Based on the expression profiles and domain characteristics of genes within this pathway, the full transporter PvABCA3, half transporter PvABCC1, and soluble protein PvABCF2 were selected for RNAi assays. The result indicated that silencing PvABCF2, but not PvABCA3 and PvABCC1, significantly increased mortality, tissue damage, and Vibrio load in V. parahaemolyticus-challenged shrimp. Further investigation revealed that PvABCF2 silencing substantially suppressed the expression of antimicrobial peptides (AMPs), components of the proPO-activating system, and key genes involved in the JAK-STAT and NF-κB signaling pathways. These findings suggested that the increased susceptibility of shrimp to V. parahaemolyticus following PvABCF2 silencing may be associated with downregulation of these specific immune-related genes. Moreover, one SNP within PvABCF2 was found to be markedly associated with resistance to V. parahaemolyticus via SNP association analysis. Collectively, these results suggested that PvABCF2 was involved in defense response against V. parahaemolyticus and identified a potential molecular marker for disease-resistant breeding.

Animals↗

An RNA polymerase III tissue and tumor atlas uncovers context-specific activities linked to 3D epigenome regulatory mechanisms.

RNA polymerase III (Pol III) produces a plethora of small noncoding RNA species involved in diverse cellular processes, from transcription regulation and splicing to RNA stability, translation, and proteostasis. Though Pol III activity is broadly coupled with cellular demands for protein synthesis and growth, a more precise understanding of gene-level dynamics and context-specific expression patterns remains missing, in part due to challenges related to sequencing and mapping Pol III-derived small ncRNAs. Here, we establish a predictive multi-tissue map of human Pol III activity across 19 tissues and 23 primary cancer subtypes by comprehensively profiling the chromatin accessibility of canonical Pol III-transcribed gene classes. Our framework relies on the unique relationship between gene accessibility and Pol III transcription, inferring activity through uniform binary classification of ATAC-seq enrichment at Pol III-transcribed genes. By characterizing multi-context gene uniformity, we provide a definition of the core Pol III transcriptome, broadly active across specialized tissues, and catalog genes with varied levels of context specificity. Our genomic Pol III atlas uncovers variable levels of activity across tissues, including sharp contraction of the Pol III transcriptome in heart and brain tissues and frequent expansion across diverse cancers. We show that both tissue- and tumor-specific genes are significantly enriched within lamina-associated domains (LADs), and that aberrant expression of nuclear lamin proteins is sufficient to induce Pol III-emergent patterns at tumor-specific genes. Together, these findings link Pol III dynamics to subnuclear compartmentalization and provide a resource for better understanding Pol III expansion and small RNA biogenesis in cancer.

Journal Article↗

Sex-specific expression of alternative transcripts in Drosophila.

BACKGROUND: Many genes produce multiple transcripts due to alternative splicing or utilization of alternative transcription initiation/termination sites. This 'transcriptome expansion' is thought to increase phenotypic complexity by allowing a single locus to produce several functionally distinct proteins. However, sex, genetic and developmental variation in the representation of alternative transcripts has never been examined systematically. Here, we describe a genome-wide analysis of sex-specific expression of alternative transcripts in Drosophila melanogaster. RESULTS: We compared transcript profiles in males and females from eight Drosophila lines (OregonR and 2b, and 6 RIL) using a newly designed 60-mer oligonucleotide microarray that allows us to distinguish a large proportion of alternative transcripts. The new microarray incorporates 7,207 oligonucleotides, satisfying stringent binding and specificity criteria that target both the common and the unique regions of 2,768 multi-transcript genes, as well as 12,912 oligonucleotides that target genes with a single known transcript. We estimate that up to 22% of genes that produce multiple transcripts show a sex-specific bias in the representation of alternative transcripts. Sexual dimorphism in overall transcript abundance was evident for 53% of genes. The X chromosome contains a significantly higher proportion of genes with female-biased transcription than the autosomes. However, genes on the X chromosome are no more likely to have a sexual bias in alternative transcript representation than autosomal genes. CONCLUSION: Widespread sex-specific expression of alternative transcripts in Drosophila suggests that a new level of sexual dimorphism at the molecular level exists.

Alternative Splicing↗

Transcriptional profiling of gene expression in response to glucose in Bacillus subtilis: regulation of the central metabolic pathways.

Chemoheterotrophic bacteria use a few central metabolic pathways for carbon catabolism and energy production as well as for the generation of the main precursors for anabolic reactions. All sources of carbon and energy are converted to intermediates of these central pathways and then further metabolized. While the regulation of genes encoding enzymes used to introduce specific substrates into the central metabolism has already been studied to some detail, much less is known about the regulation of the central metabolic pathways. In this study, we investigated the responses of the Bacillus subtilis transcriptome to the presence of glucose and analyzed the role of the pleiotropic transcriptional regulator CcpA in these responses. We found that CcpA directly represses genes involved in the utilization of secondary carbon sources. In contrast, induction by glucose seems to be mediated by a variety of different mechanisms. In the presence of glucose, the genes encoding glycolytic enzymes are induced. Moreover, the genes responsible for the production of acetate from pyruvate with a concomitant substrate-level phosphorylation are induced by glucose. In contrast, the genes required for the complete oxidation of the sugar (Krebs cycle, respiration) are repressed if excess glucose is available for the bacteria. In the absence of glucose, the genes of the Krebs cycle as well as gluconeogenic genes are derepressed. The genes encoding enzymes of the pentose phosphate pathway are expressed both in the presence and the absence of glucose, as suggested by the central role of this pathway in generating anabolic precursors.

Acetates↗

Transcriptome analysis of different multidrug-resistant gastric carcinoma cells.

Multidrug resistance (MDR) of human cancers is the major cause of failure of chemotherapy. To better understand the molecular events associated with the development of different types of MDR, two different multidrug-resistant gastric carcinoma cell lines, the MDR1/P-glycoprotein-expressing cell line EPG85-257RDB and the MDR1/P-glycoprotein-negative cell variant EPG85-257RNOV, as well as the corresponding drug-sensitive parental cell line EPG85-257P, were used for analyses of the mRNA expression profiles by cDNA array hybridization. Of more than 12,000 genes spotted on the arrays, 156 genes were detected as being significantly regulated in the cell line EPG85-257RDB in comparison to the non-resistant cell variant, and 61 genes were found to be differentially expressed in the cell line EPG85-257RNOV Seventeen genes showed a differential expression level in both multidrug-resistant gastric carcinoma variants. The impact of these alterations in gene expression levels in different multidrug-resistant gastric carcinoma cell variants is discussed.

Cell Line, Tumor↗

Distinct transcriptional profiles characterize oral epithelium-microbiota interactions.

Transcriptional profiling, bioinformatics, statistical and ontology tools were used to uncover and dissect genes and pathways of human gingival epithelial cells that are modulated upon interaction with the periodontal pathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. Consistent with their biological and clinical differences, the common core transcriptional response of epithelial cells to both organisms was very limited, and organism-specific responses predominated. A large number of differentially regulated genes linked to the P53 apoptotic network were found with both organisms, which was consistent with the pro-apoptotic phenotype observed with A. actinomycetemcomitans and anti-apoptotic phenotype of P. gingivalis. Furthermore, with A. actinomycetemcomitans, the induction of apoptosis did not appear to be Fas- or TNF(alpha)-mediated. Linkage of specific bacterial components to host pathways and networks provided additional insight into the pathogenic process. Comparison of the transcriptional responses of epithelial cells challenged with parental P. gingivalis or with a mutant of P. gingivalis deficient in production of major fimbriae, which are required for optimal invasion, showed major expression differences that reverberated throughout the host cell transcriptome. In contrast, gene ORF859 in A. actinomycetemcomitans, which may play a role in intracellular homeostasis, had a more subtle effect on the transcriptome. These studies help unravel the complex and dynamic interactions between host epithelial cells and endogenous bacteria that can cause opportunistic infections.

Aggregatibacter actinomycetemcomitans↗

A high-resolution transcript profile across the wood-forming meristem of poplar identifies potential regulators of cambial stem cell identity.

Plant growth is the result of cell proliferation in meristems, which requires a careful balance between the formation of new tissue and the maintenance of a set of undifferentiated stem cells. Recent studies have provided important information on several genetic networks responsible for stem cell maintenance and regulation of cell differentiation in the apical meristems of shoots and roots. Nothing, however, is known about the regulatory networks in secondary meristems like the vascular cambium of trees. We have made use of the large size and highly regular layered organization of the cambial meristem to create a high-resolution transcriptional map covering 220 microm of the cambial region of aspen (Populus tremula). Clusters of differentially expressed genes revealed substantial differences in the transcriptomes of the six anatomically homogenous cell layers in the meristem zone. Based on transcriptional and anatomical data, we present a model for the position of the stem cells and the proliferating mother cells in the cambial zone. We also provide sets of marker genes for different stages of xylem and phloem differentiation and identify potential regulators of cambial meristem activity. Interestingly, analysis of known regulators of apical meristem development indicates substantial similarity in regulatory networks between primary and secondary meristems.

Cell Differentiation↗

Transcriptional profiling of Mycoplasma hyopneumoniae during iron depletion using microarrays.

Mycoplasma hyopneumoniae, the causative agent of swine enzootic pneumonia and a major component of the porcine respiratory disease complex, continues to confound swine producers despite control programmes worldwide. The disease is chronic and self-limiting, but the host is subject to immunopathological changes that potentiate respiratory disease associated with other pathogens. The response of M. hyopneumoniae to environmental stress is of interest because of its relevance to virulence mechanisms in other bacterial pathogens. One of these stressors, iron deprivation, is a prominent feature of the host innate immune response, and most certainly impacts growth of mycoplasmas in vivo. To study this, microarray technology was applied to the transcriptome analysis of M. hyopneumoniae during iron deprivation. An array consisting of 632 of the 698 ORFs in the genome was used to compare the mRNA isolated from organisms grown under normal laboratory conditions with that from organisms subjected to iron deprivation with the chelator 2,2'-dipyridyl. This analysis identified 27 genes that were either up- or down-regulated in response to low-iron growth conditions (P<0.01), with an estimated false discovery rate below 10 %. These included genes encoding transport proteins, enzymes involved in energy metabolism, and components of the translation process. Ten of the 27 identified genes had no assigned function. These studies indicate that M. hyopneumoniae can respond to changes in environmental conditions, but the mechanism employed remains unknown.

2,2'-Dipyridyl↗

Neuroproteomics - the tasks lying ahead.

The brain is unquestionably the most fascinating organ. Despite tremendous progress, current knowledge falls short of being able to explain its function. An emerging approach toward improved understanding of the molecular mechanisms underlying brain function is neuroproteomics. Today's neuroscientists have access to a battery of versatile technologies both in transcriptomics and proteomics. The challenge is to choose the right strategy in order to generate new hypotheses on how the brain works. The goal of this review is therefore two-fold: first we recall the bewildering cellular, molecular, and functional complexity in the brain, as this knowledge is fundamental to any study design. In fact, an impressive complexity on the molecular level has recently re-emerged as a central theme in large-scale analyses. Then we review transcriptomics and proteomics technologies, as both are complementary. Finally, we comment on the most widely used proteomics techniques and their respective strengths and drawbacks. We conclude that for the time being, neuroproteomics should focus on its strengths, namely the identification of posttranslational modifications and protein-protein interactions, as well as the characterization of highly purified subproteomes. For global expression profiling, emphasis should be put on further development to significantly increase coverage.

Brain↗

Identification of lineage-specific zygotic transcripts in early Caenorhabditis elegans embryos.

During Caenorhabditis elegans embryogenesis, a maternally supplied transcription factor, SKN-1, is required for the specification of the mesendodermal precursor, EMS, in the 4-cell stage embryo. When EMS divides, it gives rise to a mesoderm-restricted precursor, MS, and an endoderm-restricted precursor, E. To systematically identify genes that function as key regulators of MS and/or E-derived tissues, we identified, by microarray analyses, genes that are newly transcribed within a short developmental window (approximately 30 min) encompassing the generation and fate specification of the MS and E blastomeres. By comparing total cDNAs generated from individual, carefully staged embryos, we identified 275 genes up-regulated in 12-cell embryos compared to 4-cell embryos. Fifty of these 275 genes are down-regulated in 12-cell skn-1 mutant embryos and are designated skn-1-dependent zygotic (sdz) genes. The spatial and temporal expression patterns in C. elegans embryos of 10 randomly selected sdz genes were analyzed by a nuclear GFP reporter driven by the endogenous 5' regulatory sequence of each gene. GFP expression, although absent at the 4-cell stage, was detected at the 12- to 16-cell stage for all 10 genes and was restricted to EMS-derived lineages for 7 of the 10. Among the seven lineage-specific genes, three genes are expressed equally in both MS and E lineages, two are expressed exclusively or predominantly in the MS lineage, and two are expressed exclusively in the E lineage. Depletion of skn-1 by RNAi abolishes the expression of all seven reporter transgenes in vivo, confirming that these genes are indeed skn-1 dependent. These results demonstrate the successful combination of single-staged embryo cDNAs, genetic mutants, and whole transcriptome microarray analysis to identify stage- and lineage-specific transcripts in early C. elegans embryos.

Animals↗

CAGE Basic/Analysis Databases: the CAGE resource for comprehensive promoter analysis.

Cap-analysis gene expression (CAGE) Basic and Analysis Databases store an original resource produced by CAGE, which measures expression levels of transcription starting sites by sequencing large amounts of transcript 5' ends, termed CAGE tags. Millions of human and mouse high-quality CAGE tags derived from different conditions in >20 tissues consisting of >250 RNA samples are essential for identification of novel promoters and promoter characterization in the aspect of expression profile. CAGE Basic Database is a primary database of the CAGE resource, RNA samples, CAGE libraries, CAGE clone and tag sequences and so on. CAGE Analysis Database stores promoter related information, such as counts of related transcripts, CpG islands and conserved genome region. It also provides expression profiles at base pair and promoter levels. Both databases are based on the same framework, CAGE tag starting sites, tag clusters for defining promoters and transcriptional units (TUs). Their associations and TU attributes are available to find promoters of interest. These databases were provided for Functional Annotation Of Mouse 3 (FANTOM3), an international collaboration research project focusing on expanding the transcriptome and subsequent analyses. Now access is free for all users through the World Wide Web at http://fantom3.gsc.riken.jp/.

Animals↗

Experimental validation of the regulated expression of large numbers of non-coding RNAs from the mouse genome.

Recent large-scale analyses of mainly full-length cDNA libraries generated from a variety of mouse tissues indicated that almost half of all representative cloned sequences did not contain an apparent protein-coding sequence, and were putatively derived from non-protein-coding RNA (ncRNA) genes. However, many of these clones were singletons and the majority were unspliced, raising the possibility that they may be derived from genomic DNA or unprocessed pre-mRNA contamination during library construction, or alternatively represent nonspecific "transcriptional noise." Here we show, using reverse transcriptase-dependent PCR, microarray, and Northern blot analyses, that many of these clones were derived from genuine transcripts of unknown function whose expression appears to be regulated. The ncRNA transcripts have larger exons and fewer introns than protein-coding transcripts. Analysis of the genomic landscape around these sequences indicates that some cDNA clones were produced not from terminal poly(A) tracts but internal priming sites within longer transcripts, only a minority of which is encompassed by known genes. A significant proportion of these transcripts exhibit tissue-specific expression patterns, as well as dynamic changes in their expression in macrophages following lipopolysaccharide stimulation. Taken together, the data provide strong support for the conclusion that ncRNAs are an important, regulated component of the mammalian transcriptome.

Animals↗

Chemo-selective proteomics in microbial systems.

SUMMARYOver the past two decades, the field of bioorthogonal chemistry has transitioned from emerging to an established cornerstone of scientific inquiry. In parallel, advances in microbial and host-microbe research have highlighted the need for functional approaches that extend beyond genomic and transcriptomic analyses to directly interrogate protein-level activity. Despite this need, proteomic strategies capable of resolving dynamic, heterogeneous, and low-abundance protein populations remain underdeveloped in microbial systems. This review highlights the convergence of chemo-selective proteomic technologies with microbial biology, focusing on bioorthogonal non-canonical amino acid tagging (BONCAT), activity- or affinity-based protein profiling, and bioorthogonal post-translational modifications, and comments on possibilities for novel applications for the use of click chemistry-based tools in the functional interrogation of microbial systems. Together, these strategies enable spatiotemporal resolution of protein synthesis, selective profiling of microbial subpopulations, and direct characterization of protein activity and regulation in complex biological contexts, including single-species cultures, host-associated environments, and polymicrobial communities. Continued development and utilization of these technologies will enable deeper mechanistic insight into how microbial systems function and respond to environmental and host-derived cues.

bioorthogonal chemistry↗