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Plant peroxisomes.

Peroxisomes, one of single membrane-bound organelles, are present ubiquitously in eukaryotic cells. They were originally identified as organelles for production of hydrogen peroxide, the degradation of its hydrogen peroxide, and metabolism of fatty acids, which are functions common to almost all the organisms. Meanwhile, photorespiration and assimilation of symbiotically induced nitrogen are plant-specific functions. Recent postgenetic approaches such as transcriptome and proteome showed that plant peroxisomes are differentiated in various tissues, and revealed that peroxisomes have more important roles in various metabolic processes including biosynthesis of plant hormones than we speculated. All peroxisomal proteins, including metabolic enzymes in the matrix, membrane proteins, and factors responsible for peroxisome biogenesis, are nuclear encoded, and are provided from the outside of peroxisomes. Peroxisome biogenesis, such as protein transport, division, and enlargement, requires various complicated steps and is one of the most intriguing topics. Analyses using peroxisome biogenesis mutants and the whole-scale sequencing projects among several organisms revealed the existence of essential factors responsible for peroxisome biogenesis such as peroxins. This review addresses a comprehensive issue relating to function and biogenesis of plant peroxisomes and Arabidopsis mutants that have been accelerating our understanding of peroxisomes in planta.

Peroxisomes↗

ICE1: a regulator of cold-induced transcriptome and freezing tolerance in Arabidopsis.

Cold temperatures trigger the expression of the CBF family of transcription factors, which in turn activate many downstream genes that confer chilling and freezing tolerance to plants. We report here the identification of ICE1 (inducer of CBF expression 1), an upstream transcription factor that regulates the transcription of CBF genes in the cold. An Arabidopsis ice1 mutant was isolated in a screen for mutations that impair cold-induced transcription of a CBF3 promoter-luciferase reporter gene. The ice1 mutation blocks the expression of CBF3 and decreases the expression of many genes downstream of CBFs, which leads to a significant reduction in plant chilling and freezing tolerance. ICE1 encodes a MYC-like bHLH transcriptional activator. ICE1 binds specifically to the MYC recognition sequences in the CBF3 promoter. ICE1 is expressed constitutively, and its overexpression in wild-type plants enhances the expression of the CBF regulon in the cold and improves freezing tolerance of the transgenic plants.

Acclimatization↗

Enhancer trapping reveals widespread circadian clock transcriptional control in Arabidopsis.

The circadian clock synchronizes the internal biology of an organism with the environment and has been shown to be widespread among organisms. Microarray experiments have shown that the circadian clock regulates mRNA abundance of about 10% of the transcriptome in plants, invertebrates, and mammals. In contrast, the circadian clock regulates the transcription of the virtually all cyanobacterial genes. To determine the extent to which the circadian clock controls transcription in Arabidopsis, we used in vivo enhancer trapping. We found that 36% of our enhancer trap lines display circadian-regulated transcription, which is much higher than estimates of circadian regulation based on analysis of steady-state mRNA abundance. Individual lines identified by enhancer trapping exhibit peak transcription rates at circadian phases spanning the complete circadian cycle. Flanking genomic sequence was identified for 23 enhancer trap lines to identify clock-controlled genes (CCG-ETs). Promoter analysis of CCG-ETs failed to predict new circadian clock response elements (CCREs), although previously defined CCREs, the CCA1-binding site, and the evening element were identified. However, many CCGs lack either the CCA1-binding site or the evening element; therefore, the presence of these CCREs is insufficient to confer circadian regulation, and it is clear that additional elements play critical roles.

Arabidopsis↗

Biocontrol effect of a solid-state fermentation-derived extract mixture of Trichoderma asperellum on sunflower Sclerotinia rot and associated host defense responses.

Sclerotinia disease is a destructive fungal disease of sunflowers, soybeans, and other economically important crops, causing substantial yield loss and quality deterioration. Long-term reliance on dose-dependent broad-spectrum fungicides is constrained by resistance risks and potential environmental burdens, creating tension with the sustainability goal of "reducing pesticide use while improving efficacy." Here, we explore a Trichoderma spp.-based microbial disease management strategy. Whole-genome sequencing of Trichoderma asperellum TCS007 isolated from Antarctic marine sediments, coupled with genome mining, predicted diverse biosynthetic gene clusters putatively associated with siderophores, polyketides, nonribosomal peptides, and terpenoids; the corresponding metabolites are not chemically confirmed and require further validation. Using a solid-state fermentation workflow, we prepared a fermentation-derived extract mixture (TCS007-SSF-Ex). In vitro assays showed dose-dependent inhibition of Sclerotinia sclerotiorum by TCS007-SSF-Ex (EC50 = 1.252 mg/L), and microscopy revealed cellular damage-consistent changes, including organelle disruption and plasmolysis. Pathogen transcriptomic and metabolism-related analyses indicated broad perturbations in organelle biogenesis and metabolic processes, with significant alterations in pathways associated with succinate, D-glucose, and phenylacetate; these results are consistent with growth inhibition and reduced pathogenicity, but specific molecular targets and causal links remain to be validated. In vivo, under certain application conditions, triple applications increased APX activity (+492.5%) and β-1,3-glucanase activity (+419.6%). Collectively, this work supports a "pathogen suppression-host defense induction" framework and facilitates subsequent identification of active components and mechanistic validation.IMPORTANCESclerotinia diseases cause recurrent and economically important losses in oilseed crops, while long-term fungicide use is constrained by resistance risks and environmental burdens. Trichoderma-based biocontrol is a promising complementary strategy, yet evidence supporting metabolite-containing Trichoderma-derived preparations as immune elicitors remains less consolidated than that for living inoculants, and scalable production routes are still needed. Here, we examine an Antarctic marine sediment-derived strain, Trichoderma asperellum TCS007, and a solid-state fermentation (SSF)-derived extract mixture (TCS007-SSF-Ex) produced via solid-state fermentation. We combine in vitro antifungal assays, pathogen ultrastructural observations, and correlative omics analyses with in vivo measurements of sunflower defense enzymes (APX and β-1,3-glucanase) to evaluate a "pathogen suppression-host defense induction" framework. Our findings support the potential of SSF-derived Trichoderma metabolite mixtures for greener management of Sclerotinia disease and provide a foundation for future chemical identification of active components and mechanistic validation.

Ascomycota↗

Application of expression genomics for predicting treatment response in cancer.

During tumor progression, multiple genetic changes in the genome vastly alter the transcriptomes of cancers. Some of these changes, including the mutations of various growth regulatory genes as well as alterations in the transcription of a large number of genes, may lead to resistance to treatment. Therefore, capturing such genomic information of the tumors would enable a physician to decide on the course of treatment options clinically available. Currently, it is still not feasible to identify all the genetic mutations that have occurred in a patient's cancer genome. However, the advent of DNA microarray coupled with the completion of the human genome sequence and the identification of all its genes, have made possible genome-wide gene expression profiling of the cancer genome. In this review, we will focus on the application of expression genomics for identifying signature gene expression profiles in primary cancers to predict response to either radio- or chemotherapy. We envision that transcription profiling of the cancer genomes ultimately will not only reveal how altered gene expression results in resistance to treatment, but also be exploited for predicting and personalizing cancer therapy.

Animals↗

A Genome-wide view of the Escherichia coli BasS-BasR two-component system implicated in iron-responses.

Histidine-to-aspartate (His-->Asp) phosphorelay (or two-component) systems are very common signal transduction mechanisms that are implicated in a wide variety of cellular responses to environmental stimuli in both prokaryotes and eukaryotes. Determination of the entire genomic sequence of Escherichia coli revealed that this gram-negative bacterium has 29 His-kinases and 32 response regulators. Of the 29 His-kinases, 23 have already been experimentally characterized at least to some extent in terms of their physiological functions. No physiological stimulus has yet been identified for each of the remaining 6 His-kinases (BasS, CreC, RstB, YfhK, YehU, and YpdA). Here we characterized the BasS-BasR two-component system with reference to its physiological function, taking genetic approaches together with genome-wide transcriptome profiling. First we showed that the hypothetical yfbE operon that appears to be implicated in the modification of lipopolysaccharides is regulated at the level of transcription in response to external iron, and then we showed that the BasS-BasR system is essential for this iron-dependent induction of yfbE. Another PhoQ-PhoP two-component system was also implicated in the full induction of yfbE in response to iron, but it was not essential. To gain more insight into the BasS-BasR system, we conducted genome-wide transcriptome analysis by microarray, finding that many of the uncovered putative iron-induced and BasS-BasR-dependent genes are somehow associated with acidic and/or anaerobic growth conditions. In this respect, it was found that mutant cells defective in the BasS-BasR system were sensitive to mild-acid growth conditions in the presence of a relatively high concentration of iron. These results are discussed with regard to a comprehensive picture of the His-->Asp phosphorelay signaling network in E. coli.

Aspartic Acid↗

Web-based data warehouse on gene expression in human colorectal cancer.

Based on biomedical literature databases, we tried a first step for constructing a gene expression "data warehouse" specific to human colorectal cancer (CRC). Results of genome-wide transcriptomic research were available from 12 studies, using various technologies, namely, SAGE, cDNA and oligonucleotide arrays, and adaptor-tagged amplification. Three studies analyzed CRC cell lines and nine studies of human samples. The total number of patients was 144. Out of 982 up- or down-regulated genes, 863 (88%) were found to be differentially expressed in a single study, 88 in two studies, 22 in three studies, 7 in four studies, and only 2 genes in six studies. Eight large-scale proteomics studies were published in CRC, using 2-D-, SDS- or free-flow electrophoresis, involving only 11 patients. Out of 408 differentially expressed proteins, 339 (83%) were found to be differentially expressed only in a single study, 16 in three studies, 10 in four studies, 3 in five, and 1 in eight studies. Confirmation at proteome level of results obtained with large-scale transcriptomics studies was possible in 25%. This proportion was higher (67%) for reproducing proteome results using transcriptomics technologies. Obviously, reproducibility and overlapping between published gene expression results at proteome and transcriptome level are low in human CRC. Thus, the development of standardized processes for collecting samples, storing, retrieving, and querying gene expression data obtained with different technologies is of central importance in translational research.

Colorectal Neoplasms↗

Specific effects of microRNAs on the plant transcriptome.

Most plant microRNAs (miRNAs) have perfect or near-perfect complementarity with their targets. This is consistent with their primary mode of action being cleavage of target mRNAs, similar to that induced by perfectly complementary small interfering RNAs (siRNAs). However, there are natural targets with up to five mismatches. Furthermore, artificial siRNAs can have substantial effects on so-called off-targets, to which they have only limited complementarity. By analyzing the transcriptome of plants overexpressing different miRNAs, we have deduced a set of empirical parameters for target recognition. Compared to artificial siRNAs, authentic plant miRNAs appear to have much higher specificity, which may reflect their coevolution with the remainder of the transcriptome. We also demonstrate that miR172, previously thought to act primarily by translational repression, can efficiently guide mRNA cleavage, although the effects on steady-state levels of target transcripts are obscured by strong feedback regulation. This finding unifies the view of plant miRNA action.

Base Pairing↗

Multilineage gene expression in human bone marrow stromal cells as evidenced by single-cell microarray analysis.

The nonhematopoietic stromal cells of the bone marrow are critical for the development of hematopoietic stem cells into functionally competent blood cells. This study addresses the question of whether bone marrow stromal cell cultures in the Dexter system propagate multiple different mesenchymal stromal cell types or one stromal cell type that expresses multiple phenotypes. Results show that isolated single stromal cells simultaneously express transcripts associated with osteoblast, fibroblast, muscle, and adipocyte differentiation. Furthermore, isolated single stromal cells simultaneously express transcripts characteristic of epithelial cells, endothelial cells, and neural/glial cells. Isolated single stromal cells also express transcripts for CD45, CD19, CD10, CD79a, and representative proto-oncogenes and transcription factors, which are typically associated with normal and neoplastic hematopoietic cells. These findings suggest that the nonhematopoietic mesenchymal cells and the hematopoietic B-lymphocytes have a common progenitor. This is consistent with the idea that progenitor cells express genes that are characteristic of the multiple lineage paths that such cells may be capable of adopting. This study demonstrates the technical feasibility of transcriptome analysis of individual primary cell-culture grown stromal cells and supports the concept that bone marrow stromal cells are relatively homogeneous and show a phenotypic signature of potential multilineage differentiation capacity.

Adult↗

Transcriptional profiling of sunflower plants growing under low temperatures reveals an extensive down-regulation of gene expression associated with chilling sensitivity.

Being able to sow early to maximize the growing season and to escape drought stress has increased the importance of low-temperature tolerance in sunflower. Yet knowledge about the molecular basis of sunflower response to low temperature is still lacking. To address this issue, nylon microarrays containing >8000 putative unigenes were developed and used. Early- and late-flowering genotypes were sown at 15 degrees C and grown until the two-leaf stage when they were subjected to 7 degrees C until the four-leaf stage. The transcriptional profiles of low temperature-grown plants (15 degrees C and 7 degrees C) were compared with those grown under standard conditions (25 degrees C). Two-step ANOVA normalization and analysis models were used to identify the differentially expressed genes. A total of 108 cDNA clones having a P-value <10(-3) were found to be differentially expressed between the low temperature-grown plants (15 degrees C and 7 degrees C) and their corresponding two-leaf- and four-leaf-stage controls across the two genotypes. About 90% of these genes were down-regulated. This includes genes potentially involved in the metabolism of carbohydrate and energy, protein synthesis, signal transduction, and transport function. Comparing gene expression profiles at 15 degrees C and 7 degrees C revealed that only four genes can be considered as differentially expressed, in both genotypes, suggesting that similar genetic programmes underlie the response of sunflower plants to these temperature regimes. The analysis also revealed that early- and late-flowering genotypes respond similarly to low-temperature tolerance as justified by the low number of genes showing a significant genotype x treatment interaction effect. It seems likely that the down-regulation and/or non-induction of genes having a critical role in low-temperature tolerance may be responsible for the sensitivity of sunflower plants to low-temperature tolerance. The results reported provide an initial characterization of the transcriptome activity of sunflower, as a chilling-sensitive plant under suboptimal temperatures, and could be of importance to reveal the potential differences between chilling-sensitive and chilling-tolerant species.

Acclimatization↗

Transcriptome analysis reveals a critical role of CHS7 and CHS8 genes for isoflavonoid synthesis in soybean seeds.

We have used cDNA microarray analysis to examine changes in gene expression during embryo development in soybean (Glycine max) and to compare gene expression profiles of two soybean cultivars that differ in seed isoflavonoid content. The analysis identified 5,910 genes that were differentially expressed in both soybean cultivars grown at two different locations for two consecutive years in one of the five different stages of embryo development. An ANOVA analysis with P value < 0.05 and < 0.01 indicated that gene expression changes due to environmental factors are greater than those due to cultivar differences. Most changes in gene expression occurred at the stages when the embryos were at 30 or 70 d after pollination. A significantly larger fraction of genes (48.5%) was expressed throughout the development and showed little or no change in expression. Transcript accumulation for genes related to the biosynthesis of storage components in soybean embryos showed several unique temporal expressions. Expression patterns of several genes involved in isoflavonoid biosynthesis, such as Phenylalanine Ammonia-Lyase, Chalcone Synthase (CHS) 7, CHS8, and Isoflavone Synthase2, were higher at 70 d after pollination in both the cultivars. Thus, expression of these genes coincides with the onset of accumulation of isoflavonoids in the embryos. A comparative analysis of genes involved in isoflavonoid biosynthesis in RCAT Angora (high seed isoflavonoid cultivar) and Harovinton (low seed isoflavonoid cultivar) revealed that CHS7 and CHS8 were expressed at significantly greater level in RCAT Angora than in Harovinton. Our study provides a detailed transcriptome profiling of soybean embryos during development and indicates that differences in the level of seed isoflavonoids between these two cultivars could be as a result of differential expression of CHS7 and CHS8 during late stages of seed development.

Acyltransferases↗

Towards deciphering phloem: a transcriptome analysis of the phloem of Apium graveolens.

Events occurring in the phloem tissue are key to understanding a wide range of developmental and physiological processes in vascular plants. While a considerable amount of molecular information on phloem proteins has emerged in the past decade, a unified picture of the molecular mechanisms involved in phloem differentiation and function is still lacking. New models to increase our understanding of this complex tissue can be created by the development of global approaches such as genomic analysis. In order to obtain a comprehensive overview of the molecular biology of the phloem tissue, we developed a genomic approach using Apium graveolens as a model. cDNA libraries were constructed from mRNAs extracted from isolated phloem of petioles. Expression data obtained from the analysis of 989 expressed sequence tags (ESTs) and the transcript profile deduced from a cDNA macroarray of 1326 clones were combined to identify genes showing distinct expression patterns in the vascular tissues. Comparisons of expression profiles obtained from the phloem, xylem and storage parenchyma tissues uncovered tissue-specific differential expression patterns for given sets of genes. The major classes of mRNAs predominantly found in the phloem encode proteins related to phloem structure, metal homeostasis or distribution, stress responses and degradation or turnover of proteins. Of great interest for future studies are the genes we found to be specifically expressed in the phloem but for which the function is still unknown, and also those genes described in previous reports to be up or downregulated by specific interactions. From a broader prospective, our results also clearly demonstrate that cDNA macroarray technology can be used to identify the key genes involved in various physiological and developmental processes in the phloem.

Apium↗

De Novo Assembly of the Trypanosoma congolense Genome Reveals an Organization Influenced by Antigenic Variation but Distinct from Trypanosoma brucei.

Antigenic variation allows pathogens to evade mammalian adaptive immunity through the continuous change in exposed antigens. In African trypanosomes, antigenic variation involves changes in expressed Variant Surface Glycoproteins (VSGs). Understanding of VSG expression control and change amongst African trypanosomes is most advanced in Trypanosoma brucei. In the important animal trypanosome, Trypanosoma congolense, incomplete genome assembly has held back understanding of the mechanics of antigenic variation. Here, we have used long-read DNA sequencing and Hi-C DNA interaction analysis to provide a telomere-to-telomere assembly of the T. congolense genome. This assembly reveals a genome comprising 12 diploid chromosomes, one tetraploid chromosome, and more than 100 small chromosomes. With this assembly we reveal several features of VSG organization and expression that differ from T. brucei. The majority of the T. congolense VSG archive, estimated at &#x223c;1,500 genes, localizes to subtelomeres in 12 of the 13 large chromosomes, but these loci are notably smaller than are found in T. brucei. Furthermore, transcriptome analysis suggests expression of VSGs across the T. congolense subtelomeres, which are not separated within the nucleus from non-VSG chromosome regions, suggesting that there is no dedicated VSG expression site. Strikingly, one chromosome contains approximately 40% of the VSG archive and is largely transcriptionally silent, potentially acting as the major reservoir of new VSG variants. Finally, we show that VSG expression can be detected from multiple small chromosomes. In summary, the new genome assembly provides a platform for understanding a potentially unusual operation of VSG expression and switching in T. congolense.

Trypanosoma congolense↗

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↗

Integrative multi-omics and single-cell analysis identifies EGFR pathway activation and metabolic reprogramming as potential synthetic lethal vulnerabilities in resistance to the FGFR inhibitor AZD4547.

BACKGROUND: Although fibroblast growth factor receptor (FGFR) inhibitors (FGFRi) have demonstrated clinical promise, the inevitable emergence of acquired resistance remains a critical bottleneck, severely compromising their long-term clinical efficacy. The pan-cancer molecular landscape and heterogeneous mechanisms driving this resistance, ranging from genetic alterations to dynamic network rewiring, remain poorly understood. METHODS: We integrated large-scale pharmacogenomic profiling of the FGFR inhibitor AZD4547 from the GDSC2 and PRISM databases with single-cell RNA sequencing to dissect the multi-omics landscape of FGFRi resistance across 312 cell lines from 8 cancer types. This multi-omics framework was further extended by machine learning modeling and systematic synthetic lethality screening to uncover actionable therapeutic targets. In vitro viability assays and western blot analysis were subsequently conducted to experimentally evaluate the predicted FGFR-EGFR synthetic lethality. RESULTS: Our dual-database analysis unveiled a multi-dimensional atlas of FGFRi resistance. We identified cancer-specific genomic drivers, such as ELF4 amplification in glioblastoma, alongside key transcriptomic markers including UCP2 and FSCN1, highlighting a shift towards metabolic reprogramming and epithelial-mesenchymal transition (EMT). Single-cell analysis unveiled that resistance is linked to the heterogeneous enrichment of baseline subpopulations characterized by distinct metaprograms, including cell-cycle dysregulation. Furthermore, a random forest model built on a LASSO-derived transcriptomic signature was constructed, demonstrating promising predictive capability for AZD4547 sensitivity (mean test-set AUC&#x2009;=&#x2009;0.73, 95% CI [0.63, 0.80]); the signature generalized well to erdafitinib but showed limited transferability to some other FGFR inhibitors (e.g. pemigatinib, BGJ398). Most notably, our synthetic lethal screening revealed a convergent reliance on compensatory RTK signaling (specifically EGFR pathway enrichment) and downstream MAPK/PI3K cascades in resistant phenotypes, providing converging computational evidence for EGFR pathway activation as an adaptive bypass mechanism. This predicted synthetic lethality was experimentally supported in two FGFR-dependent cell line models (RT112 and CCLP1), in which combined FGFR-EGFR inhibition produced marked synergistic antiproliferative effects. CONCLUSIONS: This study establishes a comprehensive multi-omics atlas of resistance to the FGFR inhibitor AZD4547, delineating convergent mechanisms of metabolic reprogramming and EGFR-mediated bypass signaling. Our findings characterize the resistance as a dynamic network rewiring and nominate rational combination strategies to overcome this therapeutic bottleneck. While FGFR-EGFR co-inhibition is experimentally supported, metabolic co-targeting remains a computationally derived, hypothesis-generating strategy.

Benzamides↗

REG3&#x3b1; is a Predictive Biomarker of Complicated Disease from Preclinical through Established Crohn's Disease.

BACKGROUND: Regenerating islet-derived 3-alpha (REG3&#x3b1;) is a serum biomarker in patients with graft-versus-host disease (GVHD) linked to 6-month mortality. REG3&#x3b1; is produced by intestinal Paneth cells, which are implicated in Crohn's disease (CD) pathophysiology. OBJECTIVE: To assess associations between serum REG3&#x3b1; and progressive CD DESIGN: Serum REG3&#x3b1; was measured in two cross-sectional (M: Mount Sinai, L: Leuven) and a pre-diagnostic cohort (P: PREDICTS) with serial samples up to 10 years before CD diagnosis. Tissue REG3&#x3b1; expression was assessed via bulk RNA sequencing from paired ileal and colonic biopsies. Serum REG3&#x3b1; and tissue REG3&#x3b1; were associated with CD progression (hospitalization, surgery, steroid course, or new advanced therapy). Single-cell RNA sequencing data explored associations between REG3&#x3b1; expression, Paneth cell phenotypes, and CD. RESULTS: In 394 patients, high serum REG3&#x3b1; associated with CD progression, independent of C-reactive protein and endoscopic activity (M: HR 1.9 (95%CI 1.3-2.8); L: HR 2.9 (95%CI 1.9-4.6), both p<0.001). The association persisted in patients with mild or inactive CD. In the pre-diagnostic cohort, high serum REG3&#x3b1; predicted the development of CD, particularly complicated (B2/3) and surgical presentations, up to 10 years before diagnosis (P). Analysis of REG3&#x3b1; expression and Paneth cell transcriptomes suggested that CD is associated with loss of regenerative Paneth cell populations and enrichment in REG3&#x3b1;-expressing populations, suggesting a mechanism through which changes in serum REG3&#x3b1; associate with complicated CD. CONCLUSION: Serum REG3&#x3b1; holds potential as a non-invasive, prognostic biomarker in CD, independent of disease activity. High serum REG3&#x3b1;, even years before diagnosis, is linked to a complicated disease course.

Crohn&#x2019;s Disease↗

Molecular signature analysis: using the myocardial transcriptome as a biomarker in cardiovascular disease.

With the emergence of microarray technology, it is now possible to simultaneously assess the expression of tens of thousands of gene transcripts, providing a resolution and precision of phenotypic characterization not previously possible. In the field of cardiomyopathy, microarray studies have largely focused on gene discovery, identifying differentially expressed genes characteristic of diverse disease states, through which novel genetic pathways and potential therapeutic targets may be elucidated. However, gene expression profiling may also be used to identify a pattern of genes (a molecular signature) that serves as a biomarker for clinically relevant parameters. One study thus far does demonstrate that a molecular signature can accurately identify etiology in cardiovascular disease, supporting ongoing efforts to incorporate expression-profiling-based biomarkers in determining prognosis and response to therapy in heart failure. Microarray research in cardiomyopathy is still in its earliest stages. Nevertheless, the ultimate potential application of transcriptome-based molecular signature analysis is individualization of the management of patients with heart failure, whereby a patient with a newly diagnosed cardiomyopathy could, through molecular signature analysis, be offered an accurate assessment of prognosis and how individualized medical therapy could affect his or her outcome.

Biomarkers↗

Gene expression profiling of cultured human NF1 heterozygous (NF1+/-) melanocytes reveals downregulation of a transcriptional cis-regulatory network mediating activation of the melanocyte-specific dopachrome tautomerase (DCT) gene.

One of the major primary features of the neurocutaneous genetic disorder Neurofibromatosis type 1 are the hyperpigmentary café-au-lait macules where disregulation of melanocyte biology is supposed to play a key etiopathogenic role. To gain better insight into the possible role of the tumor suppressor gene NF1, a transcriptomic microarray analysis was performed on human NF1 heterozygous (NF1+/-) melanocytes of a Neurofibromatosis type 1 patient and NF1 wild type (NF1+/+) melanocytes of a healthy control patient, both cultured from normally pigmented skin and hyperpigmented lesional café-au-lait skin. From the magnitude of gene effects, we found that gene expression was affected most strongly by genotype and less so by lesional type. A total of 137 genes had a significant twofold or more up- (72) or downregulated (65) expression in NF1+/- melanocytes compared with NF1+/+ melanocytes. Melanocytes cultured from hyperpigmented café-au-lait skin showed 37 upregulated genes whereas only 14 were downregulated compared with normal skin melanocytes. In addition, significant genotype xlesional type interactions were observed for 465 genes. Differentially expressed genes were mainly involved in regulating cell proliferation and cell adhesion. A high number of transcription factor genes, among which a specific subset important in melanocyte lineage development, were downregulated in the cis-regulatory network governing the activation of the melanocyte-specific dopachrome tautomerase (DCT) gene. Although the results presented have been obtained with a restricted number of patients (one NF1 patient and one control) and using cDNA microarrays that may limit their interpretation, the data nevertheless addresses for the first time the effect of a heterozygous NF1 gene on the expression of the human melanocyte transcriptome and has generated several interesting candidate genes helpful in elucidating the etiopathology of café-au-lait macules in NF1 patients.

Cells, Cultured↗