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Comparative Transcriptomic Analysis of Human Macrophages During Mycobacterium avium Versus Mycobacterium tuberculosis Infection.

The treatment of Mycobacterium avium (Mav) infection, responsible for over 80% of nontuberculous mycobacterial pulmonary disease, remains challenging due to rising antibiotic resistance and unsatisfactory success rates. Hence, there is a need for a deeper understanding of host-pathogen interactions to inform the development of alternative therapeutic approaches, like host-directed therapy (HDT), aimed at improving host antimycobacterial defenses. However, compared to Mycobacterium tuberculosis (Mtb) infections, knowledge of host-pathogen interactions for Mav infection is still limited. To address this knowledge gap, we performed a genome-wide host transcriptomic analysis of Mav-infected primary human macrophages-the primary host cell-alongside Mtb-infected macrophages to leverage insights from Mtb research. Our findings show substantial overlap in the gene expression patterns between Mav-infected and Mtb-infected macrophages, including induction of cytokine responses and modulation of various G-protein coupled receptors (GPCRs) involved in (lipid-mediated) macrophage immune functions. Notable differences were observed in the expression of immediate early genes (IEGs), phospholipases, and genes of the GTPase of immunity-associated protein (GIMAP) family. This study laid a foundation for identifying both shared and Mav-specific host response pathways, providing direction for future investigations into host-pathogen interactions during Mav infection and the identification of novel targets for HDT.

Humans↗

Global transcriptome analysis of genetically identified neurons in the adult cortex.

The enormous cellular complexity of the brain is a major obstacle for gene expression profiling of neurological disease models, because physiologically relevant changes of transcription in a specific neuronal subset are likely to be lost in the presence of other neurons and glia. We solved this problem in transgenic mice by labeling genetically defined cells with a nuclear variant of GFP. When combined with laser-directed microdissection, intact RNA from unfixed, freeze-dried sections can be isolated, which is a prerequisite for high-quality global transcriptome analysis. Here, we compared gene expression profiles between pyramidal motor neurons and pyramidal somatosensory neurons captured from layer V of the adult neocortex. One striking feature of motor neurons is the elevated expression of ribosomal genes and genes involved in ATP synthesis. This suggests a molecular adaptation of the upper motor neurons to longer axonal projections and higher electrical activity. These molecular signatures were not detected when cortical layers and microareas were analyzed in toto. Additionally, we used microarrays to determine the global mRNA expression profiles of microdissected Purkinje cells and cellularly complex cerebellar cortex microregions. In summary, our analysis shows that cellularly complex targets lead to averaged gene expression profiles that lack substantial amounts of cell type-specific information. Thus, cell type-restricted sampling strategies are mandatory in the CNS. The combined use of a genetic label with laser-microdissection offers an unbiased approach to map patterns of gene expression onto practically any cell type of the brain.

Adenosine Triphosphate↗

Transcriptomal analysis of failing and nonfailing human hearts.

Heart failure is a multifactorial disease that may result from different initiating events. To contribute to an improved comprehension of normal cardiac function and the molecular events leading to heart failure, we performed large-scale gene expression analysis of failing and nonfailing human ventricle. Our aim was to define and compare expression profiles of 4 specific pathophysiological cardiac situations: 1) left ventricle (LV) from nonfailing heart; 2) LV from failing hearts affected by dilated cardiomyopathy (DCM); 3) LV from failing hearts affected by ischemic CM (ICM); 4) right ventricle (RV) from failing hearts affected by DCM or ICM. We used oligonucleotide arrays representing approximately 12,000 human genes. After stringent numerical analyses using several statistical tests, we identified 1,306 genes with a similar expression profile in all 4 cardiac situations, therefore representative of part of the human cardiac expression profile. A total of 95 genes displayed differential expression between failing and nonfailing heart samples, reflecting a reversal to developmental gene expression, dedifferentiation of failing cardiomyocytes, and involvement of apoptosis. Twenty genes were differentially expressed between failing LV and failing RV, identifying possible candidates for different functioning of both ventricles. Finally, no genes were found to be significantly differentially expressed between failing DCM and failing ICM LV, emphasizing that transcriptomal analysis of explanted hearts results mainly in identification of expression profiles of end-stage heart failure and less in determination of expression profiles of the underlying etiology. Taken together, our data resulted in identification of putative transcriptomal landmarks for normal and disturbed cardiac function.

Adolescent↗

Integrating GWAS and Transcriptome Analysis Identifies Candidate Genes for Kernel Starch Quality Traits in Maize.

Maize (Zea mays L.) starch quality is a complex trait with significant implications for grain processing and industrial applications. However, the genetic basis underlying starch quality, particularly for gelatinization and thermodynamic properties, remains poorly understood. In this study, we evaluated 12 starch quality traits, including seven gelatinization characteristics, four thermodynamic traits, and kernel starch content (KSC) in a diverse panel of 335 maize inbred lines. Considerable phenotypic variation was observed for all traits. A total of 228 quantitative trait loci (QTLs) were significantly associated with 12 starch quality traits through genome-wide association studies (GWAS). By integrating a dynamic transcriptome analysis of two maize inbred lines with contrasting starch quality, we identified 60 candidate genes. One gene, waxy1, encoding a starch synthase, was found to be associated with enthalpy of gelatinization (ΔHgel) and pasting temperature (Ptemp). Six variants in waxy1 contributed to natural variation in ΔHgel and Ptemp, and a cost-effective InDel and two PARMS-based molecular markers were developed and validated in 144 maize inbred lines, enabling efficient marker-assisted selection. Our findings provide key genes and molecular markers for high-quality maize breeding with improved starch properties.

Zea mays↗

Transcriptome analysis of the cowpea weevil bruchid: identification of putative proteinases and alpha-amylases associated with food breakdown.

We describe here the first systematic work to discover insect genes involved in food breakdown using a cDNA library enriched for gut-expressed transcripts from Callosobruchus maculatus. A total of 1056 clones were screened for cDNA insert-containing plasmids, and 503 nonredundant open reading frames were discovered. Twenty-three inferred genes potentially involved in digestive processes in cowpea weevil were identified, including proteinases and amylases. The predicted catalytic sites were identified in the inferred cysteine and aspartic acid proteinases, and in alpha-amylases. Transcriptome analysis of the cowpea bruchid will potentially permit gene discovery in other beetles, an insect order of major economic and ecological importance that is poorly represented in genomic databases.

Amino Acid Sequence↗

Overexpression and affinity chromatography purification of the Type III restriction endonuclease EcoP15I for use in transcriptome analysis.

The Type III restriction endonuclease EcoP15I is a multifunctional hetero-oligomeric enzyme that recognizes the non-symmetric DNA sequence 5'-CAGCAG. For efficient cleavage, EcoP15I needs the interaction with two copies of the recognition sequence that have to be inversely oriented in the DNA double strand. The enzyme cuts the upper DNA strand 25-26 bp and the lower DNA strand 27-28 bp, respectively, downstream of the recognition sequence-a distinct feature that makes the enzyme particularly valuable for gene expression profiling methods relying on the SAGE procedure (Matsumura et al., PNAS 100, 15718, 2003). Because the broader use of this transcriptome analysis method requires the availability of larger amounts of restriction endonuclease EcoP15I and the enzyme is not commercially available, we have cloned the genes coding for the EcoP15I restriction endonuclease into pQE-16 plasmid vector that provides the enzyme with a C-terminal 6xHis-tag. After Ni-NTA affinity chromatography and ion exchange chromatography on heparin sepharose, we obtained 5mg homogeneous EcoP15I per gram cell pellet within 1-2 day(s). Moreover, the C-terminally 6xHis-tagged EcoP15I restriction endonuclease shows comparable enzymatic activity as the untagged enzyme.

Amino Acid Sequence↗

Transcriptome analysis of a shikimic acid producing strain of Escherichia coli W3110 grown under carbon- and phosphate-limited conditions.

Shikimic acid, which is produced in the aromatic amino acid pathway in plants and microorganisms, is an industrially interesting chiral starting material for the synthesis of many chemical substances, e.g. the influenza medicine Tamiflu. When produced by genetically modified Escherichia coli it has previously been found that carbon-rich conditions (e.g. phosphate-limitation) favors production of shikimic acid over shikimate pathway by-products, whereas the situation is the opposite at carbon-(glucose-) limited conditions. In the present study, gene expression patterns of the shikimate producing strain W3110.shik1 (W3110 with aroL deletion and plasmid-overexpressed aroF) and the wild type strain W3110 grown under carbon- and phosphate-limited (carbon-rich) chemostat conditions (D=0.23h(-1)) were analyzed. The study suggests that the by-product formation under carbon-limitation is explained by a set of upregulated genes coupled to the shikimate pathway. The genes, ydiB, aroD and ydiN, were strongly induced only in carbon-limited W3110.shik1. Compared to W3110 the lg(2)-fold changes were: 6.25 (ydiB); 3.93 (aroD) and 8.18 (ydiN). In addition, the transcriptome analysis revealed a large change in the gene expression when comparing phosphate- to carbon-limitation, which to a large part could be explained by anabolic-catabolic uncoupling, which is present under phosphate-limitation but not under carbon-limitation. Interestingly, there was also a larger difference between the two strains under carbon-limitation than under phosphate-limitation. The reason for this difference is interpreted in terms of starvation for aromatic amino acids under carbon-limitation which is relieved under phosphate-limitation due to an upregulation of aroK and aroA.

Bioreactors↗

Transcriptome analysis of Sinorhizobium meliloti during symbiosis.

BACKGROUND: Rhizobia induce the formation on specific legumes of new organs, the root nodules, as a result of an elaborated developmental program involving the two partners. In order to contribute to a more global view of the genetics underlying this plant-microbe symbiosis, we have mined the recently determined Sinorhizobium meliloti genome sequence for genes potentially relevant to symbiosis. We describe here the construction and use of dedicated nylon macroarrays to study simultaneously the expression of 200 of these genes in a variety of environmental conditions, pertinent to symbiosis. RESULTS: The expression of 214 S. meliloti genes was monitored under ten environmental conditions, including free-living aerobic and microaerobic conditions, addition of the plant symbiotic elicitor luteolin, and a variety of symbiotic conditions. Five new genes induced by luteolin have been identified as well as nine new genes induced in mature nitrogen-fixing bacteroids. A bacterial and a plant symbiotic mutant affected in nodule development have been found of particular interest to decipher gene expression at the intermediate stage of the symbiotic interaction. S. meliloti gene expression in the cultivated legume Medicago sativa (alfalfa) and the model plant M. truncatula were compared and a small number of differences was found. CONCLUSIONS: In addition to exploring conditions for a genome-wide transcriptome analysis of the model rhizobium S. meliloti, the present work has highlighted the differential expression of several classes of genes during symbiosis. These genes are related to invasion, oxidative stress protection, iron mobilization, and signaling, thus emphasizing possible common mechanisms between symbiosis and pathogenesis.

Cluster Analysis↗

Two-dimensional transcriptome analysis in chemostat cultures. Combinatorial effects of oxygen availability and macronutrient limitation in Saccharomyces cerevisiae.

Genome-wide analysis of transcriptional regulation is generally studied by determining sets of "signature transcripts" that are up- or down-regulated relative to a reference situation when a single culture parameter or genetic modification is changed. This approach is especially relevant for defining small subsets of transcripts for use in high throughput, cost-effective diagnostic analyses. However, this approach may overlook the simultaneous control of transcription by more than one environmental parameter. This study represents the first quantitative assessment of the impact of transcriptional cross-regulation by different environmental parameters. As a model, we compared the response of aerobic as well as anaerobic chemostat cultures of the yeast Saccharomyces cerevisiae to growth limitation by four different macronutrients (carbon, nitrogen, phosphorus, and sulfur). The identity of the growth-limiting nutrient was shown to have a strong impact on the sets of transcripts that responded to oxygen availability and vice versa. We concluded that identification of reliable signature transcripts for specific environmental parameters can be obtained only by combining transcriptome data sets obtained under several sets of reference conditions. Furthermore, the two-dimensional approach to transcriptome analysis is a valuable new tool to study the interaction of different transcriptional regulation systems.

Aerobiosis↗

Phosphoproteome and transcriptome analysis of the neuronal response to a CDK5 inhibitor.

In Alzheimer's disease and amyotrophic lateral sclerosis deregulation of cyclin-dependent kinase 5 (CDK5) causes hyperphosphorylation of tau and neurofilament proteins, respectively, leading to neuronal cell death. We have demonstrated recently that pharmacological inhibition of CDK5 protects neurons under various stressful conditions (Weishaupt J. H., et al., Molec. Cell. Neurosci. 2003, 24, 489-502). To get an overview on the cellular mechanisms of action we analyzed global changes in protein phosphorylation in cultured cerebellar granule neurons by [(32)P]orthophosphate labeling after administration of a CDK5 inhibitor. Since CDK5 has recently been shown to phosphorylate and inactivate transcription factor MEF2, we included gene expression profiling using cDNA microarrays. By two-dimensional gel electrophoresis and matrix assisted laser desorption/ionisation-time of flight (MALDI-TOF)-mass spectrometry we identified several phosphoproteins that were modulated by compound administration. Among them syndapin I which is involved in vesicle recycling, and dynein light intermediate chain 2 which represents a regulatory subunit of the dynein protein complex. These findings are consistent with the known physiological function of CDK5 in synaptic signaling and axonal transport. Moreover, we detected phosphoproteins acting in neuronal surival and/or neurite outgrowth, such as cofilin and collapsin response mediator protein. Subsequent testing in cell cultures revealed that the CDK5 inhibitor blocked mitochondrial translocation of pro-apoptotic cofilin in cerebellar granule neurons and enhanced neurite outgrowth in dorsal root ganglia. Numerous genes exhibiting MEF2 consensus binding sequences were modulated by CDK5 inhibitor treatment. Among them some that may contribute to neurite elongation or neuronal survival, but also several genes functioning in synaptic transmission. Taken together, phosphoproteome and transcriptome analysis indicate that the compound promotes both neuronal survival and neurite outgrowth, but also may affect synaptic function in cultured neurons.

Animals↗

Transcriptome analysis of O3-exposed Arabidopsis reveals that multiple signal pathways act mutually antagonistically to induce gene expression.

To analyze cellular responses to ozone (O3), we performed a large-scale analysis of the Arabidopsis transcriptome after plants were exposed to O3 for 12 h. By using cDNA macroarray technology, we identified 205 non-redundant expressed sequence tags (ESTs) that were regulated by O3. Of these, 157 were induced and 48 were suppressed by O3. A substantial proportion of these ESTs had predicted functions in cell rescue/defense processes. Using these isolated ESTs, we also undertook a comprehensive investigation of how three hormones, ethylene (ET), jasmonic acid (JA), and salicylic acid (SA), interact to regulate O3-induced genes in various genetic backgrounds of Arabidopsis, such as the ET-insensitive ein2-1, JA-resistant jar1-1, and SA-insensitive npr1-1. The expression of half of the 157 induced genes, especially cell rescue/defense genes, was controlled by ET and JA signaling, indicating that O3-induced defense gene expression at this stage was mainly regulated by ET and JA. Clustering analysis of the 157 O3-induced gene expressions revealed that multiple signal pathways act mutually antagonistically to induce the expression of these genes, and many cell rescue/defense genes induced by ET and JA signal pathways were suppressed by SA signaling, suggesting that the SA pathway acts as a strong antagonist to gene expression induced by ET and JA signaling.

Arabidopsis↗

Transcriptome analysis of human autosomal trisomy.

We present transcriptome analyses of primary cultures of human fetal cells from pregnancies affected with trisomy 21 (t21) and trisomy 13 (t13). Pooled mRNA samples from t21 and t13 cases were used for comparative hybridizations to cDNA arrays with pooled mRNA from normal cells. When the array cDNAs were grouped by chromosomal location the relevant trisomic chromosome could be clearly identified as showing the most significant misregulation. The average level of transcription on the trisomic chromosome was increased only approximately 1.1-fold compared to normal cells on array analysis. Since the karyotype could be accurately predicted by the transcriptome this could provide a novel method of detecting aneusomy of unknown position. Subsequent analysis of individuals cases demonstrated that variation in transcriptional profiles between samples within each class made transcriptional karyotyping difficult without pooling or the use of arrays with a higher proportion of all human cDNAs. Interestingly, consistent differences in the relative expression levels between chromosomes were detected suggesting that genomic control mechanisms may act over larger distances than previously thought. Most (>95%) >+/-2 SD misregulated genes did not map to the trisomic chromosome and significant misregulation was more common in t13 than t21. These data support a model of a subtle primary upregulation of genes on the trisomic chromosome resulting in a secondary, generalized and more extreme transcriptional misregulation. It seems likely that the degree of this misregulation determines the severity of the phenotype in most aneuploidy.

Chromosomes, Human, Pair 13↗

Coordinated inflammatory macrophage and vascular smooth muscle cell remodeling signatures in human atherosclerosis: An integrative single-cell and bulk transcriptomic analysis.

Atherosclerotic plaque progression is shaped by coordinated inflammatory and remodeling programs involving immune cells and vascular wall cells. Inflammatory macrophage activation and vascular smooth muscle cell (VSMC) phenotypic remodeling are central features of human atherosclerosis, but their transcriptomic relationships during plaque progression remain incompletely characterized. This study integrated single-cell and bulk transcriptomic datasets to examine highly inflammatory macrophage states, VSMC remodeling-related transcriptional programs, and candidate ligand-receptor expression patterns in human atherosclerotic plaques. Human atherosclerotic plaque single-cell RNA sequencing data from GSE260657 and bulk transcriptomic data from GSE28829 were analyzed. After quality control, 7628 cells were retained for single-cell analysis. Major cell types were annotated using canonical markers, followed by reclustering of macrophages and VSMC-related cells. Functional module scoring, differential expression analysis, Gene Ontology biological process enrichment, and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to characterize macrophage transcriptional states. Slingshot was applied to infer VSMC pseudotime ordering. CellChat and NicheNet were used to prioritize candidate ligand-receptor expression patterns and ligand-associated VSMC target gene programs. External bulk transcriptomic analysis was performed to examine whether single-cell-derived inflammatory and remodeling signatures were represented at the tissue-transcriptome level during plaque progression. Macrophage reclustering identified a highly inflammatory macrophage state characterized by prominent inflammatory activation, cytokine-response, and stress-response features. Genes upregulated in this population were enriched in pathways related to tumor necrosis factor (TNF) response, nuclear factor kappa B signaling, leukocyte activation, cytokine signaling, lipid and atherosclerosis, toll-like receptor signaling, and inflammasome-associated inflammation. VSMC reclustering revealed contractile VSMCs, PTHLH+ synthetic VSMCs, KRT7+ VSMC-like cells, interferon-responsive VSMCs, pericyte-like mural cells, and osteogenic/modulated VSMCs. Pseudotime analysis showed a broad contractile-to-osteogenic/modulated transcriptional continuum accompanied by increased expression of remodeling-associated genes and selected inflammatory or remodeling-associated receptor genes. CellChat and NicheNet analyses prioritized candidate ligand-receptor and ligand-associated target gene expression patterns involving SPP1-CD44, TNF-TNFRSF1A, IL1B-IL1R1/IL1RAP, MIF-ACKR3, PDGFB-PDGFRB, and FN1-SDC1/ITGB1. In GSE28829, inflammatory macrophage-, osteogenic/modulated VSMC-, candidate ligand-receptor expression-, SPP1-CD44 candidate axis-, and NicheNet-prioritized target program-related signatures were more prominent in advanced plaques and were positively correlated with each other. This integrative transcriptomic analysis identified a highly inflammatory macrophage state and a VSMC remodeling continuum in human atherosclerotic plaques. Candidate ligand-receptor and ligand-associated target gene expression patterns linked inflammatory macrophage activation with osteogenic/modulated VSMC remodeling at the computational level. External bulk data further showed coordinated enrichment of inflammatory and remodeling signatures in advanced plaques. These findings provide a descriptive and hypothesis-generating transcriptomic framework for understanding inflammatory macrophage activation and VSMC remodeling in human atherosclerosis.

atherosclerosis↗

Global transcriptome analysis of the C57BL/6J mouse testis by SAGE: evidence for nonrandom gene order.

BACKGROUND: We generated the gene expression profile of the total testis from the adult C57BL/6J male mice using serial analysis of gene expression (SAGE). Two high-quality SAGE libraries containing a total of 76 854 tags were constructed. An extensive bioinformatic analysis and comparison of SAGE transcriptomes of the total testis, testicular somatic cells and other mouse tissues was performed and the theory of male-biased gene accumulation on the X chromosome was tested. RESULTS: We sorted out 829 genes predominantly expressed from the germinal part and 944 genes from the somatic part of the testis. The genes preferentially and specifically expressed in total testis and testicular somatic cells were identified by comparing the testis SAGE transcriptomes to the available transcriptomes of seven non-testis tissues. We uncovered chromosomal clusters of adjacent genes with preferential expression in total testis and testicular somatic cells by a genome-wide search and found that the clusters encompassed a significantly higher number of genes than expected by chance. We observed a significant 3.2-fold enrichment of the proportion of X-linked genes specific for testicular somatic cells, while the proportions of X-linked genes specific for total testis and for other tissues were comparable. In contrast to the tissue-specific genes, an under-representation of X-linked genes in the total testis transcriptome but not in the transcriptomes of testicular somatic cells and other tissues was detected. CONCLUSION: Our results provide new evidence in favor of the theory of male-biased genes accumulation on the X chromosome in testicular somatic cells and indicate the opposite action of the meiotic X-inactivation in testicular germ cells.

Animals↗

Transcriptome analysis for the chicken based on 19,626 finished cDNA sequences and 485,337 expressed sequence tags.

We present an analysis of the chicken (Gallus gallus) transcriptome based on the full insert sequences for 19,626 cDNAs, combined with 485,337 EST sequences. The cDNA data set has been functionally annotated and describes a minimum of 11,929 chicken coding genes, including the sequence for 2260 full-length cDNAs together with a collection of noncoding (nc) cDNAs that have been stringently filtered to remove untranslated regions of coding mRNAs. The combined collection of cDNAs and ESTs describe 62,546 clustered transcripts and provide transcriptional evidence for a total of 18,989 chicken genes, including 88% of the annotated Ensembl gene set. Analysis of the ncRNAs reveals a set that is highly conserved in chickens and mammals, including sequences for 14 pri-miRNAs encoding 23 different miRNAs. The data sets described here provide a transcriptome toolkit linked to physical clones for bioinformaticians and experimental biologists who wish to use chicken systems as a low-cost, accessible alternative to mammals for the analysis of vertebrate development, immunology, and cell biology.

Animals↗

Epithelial cell preparation for proteomic and transcriptomic analysis in human pancreatic tissue.

Standardized sample preparation procedures constitute a prerequisite for obtaining reliable and reproducible results in gene expression research in humans. In particular, in diseases such as pancreatic cancer and pancreatitis, isolating epithelial cells is an important step preceding such research. In pancreatic tissue, the high amount of RNAases is a further problem when it comes to obtaining high-quality RNA, and the presence of secreted proteases accelerates protein degradation. We developed a successful method that addresses these different problems. This method, which uses epithelial cell surface antibody Ber-Ep4, proteases, and RNAases inhibitors, leads to a significant enrichment (> 95% purity) of epithelial cells from fresh human tissue samples and allows for both proteomics (Western Blot, 2D PAGE) and transcriptomics studies (rtPCR, cDNA microarray). Compared with other cell purification procedures, this method is characterized by several advantages: a large quantity of cells available for downstream analysis, combined transcriptomics and proteomics studies using the same samples, better reproducibility of proteomics studies, and an acceptable yield (63%) for gene expression arrays studies. Moreover, a quality control protocol addressing the needs of the industry and the requirements of regulatory agencies is proposed.

Epithelial Cells↗

Transcriptome analysis of brown adipose tissue in Brandt's vole treated with tannic acid under cold exposure.

BACKGROUND: Tannic acid (TA) is a hydrolysable plant secondary metabolite known to influence multiple physiological processes in animals; however, its role in regulating brown adipose tissue (BAT) thermogenesis remains poorly understood. Notably, the overwinter food caches of Brandt's voles predominantly consist of Artemisia species, which are rich in TA. This study aimed to determine whether TA contributes to cold tolerance in Brandt's voles by activating BAT thermogenesis. Adult male voles were administered TA, after which the masses of BAT and inguinal white adipose tissue (iWAT) were measured, and temperature changes in BAT, the body surface, and the rectum were recorded following exposure to - 20 °C. In addition, transcriptomic analyses of BAT were performed, and the expression and protein levels of key thermogenic markers were assessed. RESULTS: The results showed that TA reduced iWAT mass while exerting minimal effects on BAT mass. TA-treated voles exhibited significantly elevated temperatures in BAT, the body surface, and the rectum after cold exposure. Histological analyses revealed that TA treatment reduced adipocyte area in iWAT while increasing the number of nuclei in brown adipocytes in BAT. In BAT, differentially expressed genes (DEGs) in voles receiving a low TA dose were significantly enriched in pathways related to fat digestion and absorption and peroxisome proliferator-activated receptor (PPAR) signaling. In contrast, DEGs in voles administered a high TA dose were predominantly associated with brown adipocyte differentiation and the upregulation of cold-induced thermogenesis. Moreover, TA administration increased the expression of FFAR4 and UCP1, as well as the protein levels of PGC-1α, PPARγ, and UCP1 following cold exposure. CONCLUSIONS: Collectively, these findings demonstrate that TA enhances cold tolerance in Brandt's voles by promoting thermogenic gene expression and stimulating brown adipocyte differentiation in BAT, providing novel insights into the role of plant secondary metabolites in mammalian cold adaptation and herbivore-plant interactions.

Animals↗

Bacillus subtilis functional genomics: global characterization of the stringent response by proteome and transcriptome analysis.

The stringent response in Bacillus subtilis was characterized by using proteome and transcriptome approaches. Comparison of protein synthesis patterns of wild-type and relA mutant cells cultivated under conditions which provoke the stringent response revealed significant differences. According to their altered synthesis patterns in response to DL-norvaline, proteins were assigned to four distinct classes: (i) negative stringent control, i.e., strongly decreased protein synthesis in the wild type but not in the relA mutant (e.g., r-proteins); (ii) positive stringent control, i.e., induction of protein synthesis in the wild type only (e.g., YvyD and LeuD); (iii) proteins that were induced independently of RelA (e.g., YjcI); and (iv) proteins downregulated independently of RelA (e.g., glycolytic enzymes). Transcriptome studies based on DNA macroarray techniques were used to complement the proteome data, resulting in comparable induction and repression patterns of almost all corresponding genes. However, a comparison of both approaches revealed that only a subset of RelA-dependent genes or proteins was detectable by proteomics, demonstrating that the transcriptome approach allows a more comprehensive global gene expression profile analysis. The present study presents the first comprehensive description of the stringent response of a bacterial species and an almost complete map of protein-encoding genes affected by (p)ppGpp. The negative stringent control concerns reactions typical of growth and reproduction (ribosome synthesis, DNA synthesis, cell wall synthesis, etc.). Negatively controlled unknown y-genes may also code for proteins with a specific function during growth and reproduction (e.g., YlaG). On the other hand, many genes are induced in a RelA-dependent manner, including genes coding for already-known and as-yet-unknown proteins. A passive model is preferred to explain this positive control relying on the redistribution of the RNA polymerase under the influence of (p)ppGpp.

Bacillus subtilis↗