scholarly journals Genomic Profiling of Iron-Responsive Genes in Salmonella enterica Serovar Typhimurium by High-Throughput Screening of a Random Promoter Library

2003 ◽  
Vol 185 (16) ◽  
pp. 4973-4982 ◽  
Author(s):  
Jaime Bjarnason ◽  
Carolyn M. Southward ◽  
Michael G. Surette
Keyword(s):  
Gene Expression ◽  
High Throughput ◽  
Salmonella Enterica ◽  
High Throughput Screening ◽  
Expression Profiles ◽  
Transport Systems ◽  
Iron Availability ◽  
Iron Storage ◽  
Promoter Library ◽  
Serovar Typhimurium

ABSTRACT The importance of iron to bacteria is shown by the presence of numerous iron-scavenging and transport systems and by many genes whose expression is tightly regulated by iron availability. We have taken a global approach to gene expression analysis of Salmonella enterica serovar Typhimurium in response to iron by combining efficient, high-throughput methods with sensitive, luminescent reporting of gene expression using a random promoter library. Real-time expression profiles of the library were generated under low- and high-iron conditions to identify iron-regulated promoters, including a number of previously identified genes. Our results indicate that approximately 7% of the genome may be regulated directly or indirectly by iron. Further analysis of these clones using a Fur titration assay revealed three separate classes of genes; two of these classes consist of Fur-regulated genes. A third class was Fur independent and included both negatively and positively iron-responsive genes. These may reflect new iron-dependent regulons. Iron-responsive genes included iron transporters, iron storage and mobility proteins, iron-containing proteins (redox proteins, oxidoreductases, and cytochromes), transcriptional regulators, and the energy transducer tonB. By identifying a wide variety of iron-responsive genes, we extend our understanding of the global effect of iron availability on gene expression in the bacterial cell.

Genomics and Systems Biology.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. sci-51-sci-51
Author(s):  
Todd R. Golub
Keyword(s):  
Gene Expression ◽  
High Throughput ◽  
Biological Networks ◽  
High Throughput Screening ◽  
Expression Profiles ◽  
Low Cost ◽  
Gene Expression Profiles ◽  
Gene Expression Signature ◽  
Small Molecule Libraries ◽  
Approved Drugs

Genomics holds particular potential for the elucidation of biological networks that underlie disease. For example, gene expression profiles have been used to classify human cancers, and have more recently been used to predict graft rejection following organ transplantation. Such signatures thus hold promise both as diagnostic approaches and as tools with which to dissect biological mechanism. Such systems-based approaches are also beginning to impact the drug discovery process. For example, it is now feasible to measure gene expression signatures at low cost and high throughput, thereby allowing for the screening libraries of small molecule libraries in order to identify compounds capable of perturbing a signature of interest (even if the critical drivers of that signature are not yet known). This approach, known as Gene Expression-Based High Throughput Screening (GE-HTS), has been shown to identify candidate therapeutic approaches in AML, Ewing sarcoma, and neuroblastoma, and has identified tool compounds capable of inhibiting PDGF receptor signaling. A related approach, known as the Connectivity Map (www.broad.mit.edu/cmap) attempts to use gene expression profiles as a universal language with which to connect cellular states, gene product function, and drug action. In this manner, a gene expression signature of interest is used to computationally query a database of gene expression profiles of cells systematically treated with a large number of compounds (e.g., all off-patent FDA-approved drugs), thereby identifying potential new applications for existing drugs. Such systems level approaches thus seek chemical modulators of cellular states, even when the molecular basis of such altered states is unknown.

scholarly journals Discovery of agents that eradicate leukemia stem cells using an in silico screen of public gene expression data

Blood ◽  
2008 ◽  
Vol 111 (12) ◽  
pp. 5654-5662 ◽  
Author(s):  
Duane C. Hassane ◽  
Monica L. Guzman ◽  
Cheryl Corbett ◽  
Xiaojie Li ◽  
Ramzi Abboud ◽  
...  
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
High Throughput ◽  
In Silico ◽  
High Throughput Screening ◽  
Drug Targets ◽  
Expression Profiles ◽  
Gene Expression Signature ◽  
Myelogenous Leukemia ◽  
Expression Signature

Abstract Increasing evidence indicates that malignant stem cells are important for the pathogenesis of acute myelogenous leukemia (AML) and represent a reservoir of cells that drive the development of AML and relapse. Therefore, new treatment regimens are necessary to prevent relapse and improve therapeutic outcomes. Previous studies have shown that the sesquiterpene lactone, parthenolide (PTL), ablates bulk, progenitor, and stem AML cells while causing no appreciable toxicity to normal hematopoietic cells. Thus, PTL must evoke cellular responses capable of mediating AML selective cell death. Given recent advances in chemical genomics such as gene expression-based high-throughput screening (GE-HTS) and the Connectivity Map, we hypothesized that the gene expression signature resulting from treatment of primary AML with PTL could be used to search for similar signatures in publicly available gene expression profiles deposited into the Gene Expression Omnibus (GEO). We therefore devised a broad in silico screen of the GEO database using the PTL gene expression signature as a template and discovered 2 new agents, celastrol and 4-hydroxy-2-nonenal, that effectively eradicate AML at the bulk, progenitor, and stem cell level. These findings suggest the use of multicenter collections of high-throughput data to facilitate discovery of leukemia drugs and drug targets.

scholarly journals High-Throughput Screening for CEBPD-Modulating Compounds in THP-1-Derived Reporter Macrophages Identifies Anti-Inflammatory HDAC and BET Inhibitors

2021 ◽  
Vol 22 (6) ◽  
pp. 3022
Author(s):  
Tatjana Ullmann ◽  
Sonja Luckhardt ◽  
Markus Wolf ◽  
Michael J. Parnham ◽  
Eduard Resch
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
High Throughput ◽  
Transcription Initiation ◽  
High Throughput Screening ◽  
Inflammatory Responses ◽  
Hdac Inhibitors ◽  
Screening Assay ◽  
Bet Inhibitors ◽  
Anti Inflammatory

This study aimed to identify alternative anti-inflammatory compounds that modulate the activity of a relevant transcription factor, CCAAT/enhancer binding protein delta (C/EBPδ). C/EBPδ is a master regulator of inflammatory responses in macrophages (Mϕ) and is mainly regulated at the level of CEBPD gene transcription initiation. To screen for CEBPD-modulating compounds, we generated a THP-1-derived reporter cell line stably expressing secreted alkaline phosphatase (SEAP) under control of the defined CEBPD promoter (CEBPD::SEAP). A high-throughput screening of LOPAC®1280 and ENZO®774 libraries on LPS- and IFN-γ-activated THP-1 reporter Mϕ identified four epigenetically active hits: two bromodomain and extraterminal domain (BET) inhibitors, I-BET151 and Ro 11-1464, as well as two histone deacetylase (HDAC) inhibitors, SAHA and TSA. All four hits markedly and reproducibly upregulated SEAP secretion and CEBPD::SEAP mRNA expression, confirming screening assay reliability. Whereas BET inhibitors also upregulated the mRNA expression of the endogenous CEBPD, HDAC inhibitors completely abolished it. All hits displayed anti-inflammatory activity through the suppression of IL-6 and CCL2 gene expression. However, I-BET151 and HDAC inhibitors simultaneously upregulated the mRNA expression of pro-inflammatory IL-1ß. The modulation of CEBPD gene expression shown in this study contributes to our understanding of inflammatory responses in Mϕ and may offer an approach to therapy for inflammation-driven disorders.

scholarly journals P02.10 FocuSCOPE: a single cell, multi-omics solution to simultaneously analyze tumor variants and microenvironment

2021 ◽  
Vol 9 (Suppl 1) ◽  
pp. A12.1-A12
Author(s):  
Y Arjmand Abbassi ◽  
N Fang ◽  
W Zhu ◽  
Y Zhou ◽  
Y Chen ◽  
...  
Keyword(s):  
Gene Expression ◽  
Tumor Microenvironment ◽  
Single Cell ◽  
High Throughput ◽  
Immune Cells ◽  
Genetic Variants ◽  
Expression Profiles ◽  
Single Cells ◽  
Gene Expression Profiles ◽  
Single Cell Sequencing

Recent advances of high-throughput single cell sequencing technologies have greatly improved our understanding of the complex biological systems. Heterogeneous samples such as tumor tissues commonly harbor cancer cell-specific genetic variants and gene expression profiles, both of which have been shown to be related to the mechanisms of disease development, progression, and responses to treatment. Furthermore, stromal and immune cells within tumor microenvironment interact with cancer cells to play important roles in tumor responses to systematic therapy such as immunotherapy or cell therapy. However, most current high-throughput single cell sequencing methods detect only gene expression levels or epigenetics events such as chromatin conformation. The information on important genetic variants including mutation or fusion is not captured. To better understand the mechanisms of tumor responses to systematic therapy, it is essential to decipher the connection between genotype and gene expression patterns of both tumor cells and cells in the tumor microenvironment. We developed FocuSCOPE, a high-throughput multi-omics sequencing solution that can detect both genetic variants and transcriptome from same single cells. FocuSCOPE has been used to successfully perform single cell analysis of both gene expression profiles and point mutations, fusion genes, or intracellular viral sequences from thousands of cells simultaneously, delivering comprehensive insights of tumor and immune cells in tumor microenvironment at single cell resolution.Disclosure InformationY. Arjmand Abbassi: None. N. Fang: None. W. Zhu: None. Y. Zhou: None. Y. Chen: None. U. Deutsch: None.

scholarly journals Multiple Factors Independently RegulatehilA and Invasion Gene Expression in Salmonella enterica Serovar Typhimurium

2000 ◽  
Vol 182 (7) ◽  
pp. 1872-1882 ◽  
Author(s):  
Robin L. Lucas ◽  
C. Phoebe Lostroh ◽  
Concetta C. DiRusso ◽  
Michael P. Spector ◽  
Barry L. Wanner ◽  
...  
Keyword(s):  
Gene Expression ◽  
Salmonella Enterica ◽  
Inorganic Phosphate ◽  
Response Regulator ◽  
Regulatory System ◽  
Negative Control ◽  
Host Cells ◽  
Uptake System ◽  
Intracellular Signals ◽  
Serovar Typhimurium

HilA activates the expression of Salmonella entericaserovar Typhimurium invasion genes. To learn more about regulation ofhilA, we isolated Tn5 mutants exhibiting reduced hilA and/or invasion gene expression. In addition to expected mutations, we identified Tn5 insertions inpstS, fadD, flhD, flhC, and fliA. Analysis of the pstS mutant indicates that hilA and invasion genes are repressed by the response regulator PhoB in the absence of the Pst high-affinity inorganic phosphate uptake system. This system is required for negative control of the PhoR-PhoB two-component regulatory system, suggesting thathilA expression may be repressed by PhoR-PhoB under low extracellular inorganic phosphate conditions. FadD is required for uptake and degradation of long-chain fatty acids, and our analysis of the fadD mutant indicates that hilA is regulated by a FadD-dependent, FadR-independent mechanism. Thus, fatty acid derivatives may act as intracellular signals to regulatehilA expression. flhDC and fliAencode transcription factors required for flagellum production, motility, and chemotaxis. Complementation studies with flhCand fliA mutants indicate that FliZ, which is encoded in an operon with fliA, activates expression of hilA, linking regulation of hilA with motility. Finally, epistasis tests showed that PhoB, FadD, FliZ, SirA, and EnvZ act independently to regulate hilA expression and invasion. In summary, our screen has identified several distinct pathways that can modulate S. enterica serovar Typhimurium's ability to express hilA and invade host cells. Integration of signals from these different pathways may help restrict invasion gene expression during infection.

scholarly journals Microbial single-cell RNA sequencing by split-pool barcoding

Science ◽  
2020 ◽  
Vol 371 (6531) ◽  
pp. eaba5257 ◽  
Author(s):  
Anna Kuchina ◽  
Leandra M. Brettner ◽  
Luana Paleologu ◽  
Charles M. Roco ◽  
Alexander B. Rosenberg ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Rna Sequencing ◽  
High Throughput ◽  
Single Cell Analysis ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Growth Stages ◽  
High Throughput Analysis ◽  
Single Cell Rna Sequencing

Single-cell RNA sequencing (scRNA-seq) has become an essential tool for characterizing gene expression in eukaryotes, but current methods are incompatible with bacteria. Here, we introduce microSPLiT (microbial split-pool ligation transcriptomics), a high-throughput scRNA-seq method for Gram-negative and Gram-positive bacteria that can resolve heterogeneous transcriptional states. We applied microSPLiT to >25,000 Bacillus subtilis cells sampled at different growth stages, creating an atlas of changes in metabolism and lifestyle. We retrieved detailed gene expression profiles associated with known, but rare, states such as competence and prophage induction and also identified unexpected gene expression states, including the heterogeneous activation of a niche metabolic pathway in a subpopulation of cells. MicroSPLiT paves the way to high-throughput analysis of gene expression in bacterial communities that are otherwise not amenable to single-cell analysis, such as natural microbiota.

scholarly journals The fimYZ Genes Regulate Salmonella enterica Serovar Typhimurium Invasion in Addition to Type 1 Fimbrial Expression and Bacterial Motility

2005 ◽  
Vol 73 (3) ◽  
pp. 1377-1385 ◽  
Author(s):  
M. Aaron Baxter ◽  
Bradley D. Jones
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Protein Interactions ◽  
Salmonella Enterica ◽  
Negative Regulator ◽  
Invasive Phenotype ◽  
Environmental Signals ◽  
Bacterial Physiology ◽  
Serovar Typhimurium

ABSTRACT An important step in Salmonella enterica serovar Typhimurium virulence is the ability to invade the intestinal epithelium. The invasion process requires a large number of genes encoded on Salmonella pathogenicity island 1 (SPI-1) at centisome 63 as well as genes located in other positions throughout the chromosome. Expression of the invasive phenotype is tightly regulated by environmental cues that are processed by a complex regulatory scheme. A central player in the invasion regulatory pathway is the HilA protein, which is transcriptional activator belonging to the OmpR/ToxR family. A number of positive regulators (hilC, hilD, fis, sirA/barA, csrAB, phoBR, fadD, envZ/ompR, and fliZ) and negative regulators (hha, hilE, lon, ams, phoP c and pag) have been identified that are able to alter expression of hilA transcription. Recent work has found that hilA transcription requires the HilD protein for activation. Other work has emphasized the importance of HilE as a negative regulator of hilA. Overexpression of hilE superrepresses hilA transcription, as well as the invasive phenotype. Two-hybrid experiments suggest that HilE exerts its regulatory influence on hilA through protein-protein interactions with HilD as the protein does not bind to the hilA promoter nor does it affect hilD transcription. As it seems likely that hilE plays an important role in translating environmental signals into invasion gene regulation, we have attempted to identify how the hilE gene itself is regulated. Our results indicate that the fimYZ genes, response regulatory proteins involved in type 1 fimbrial gene expression and recently implicated in motility gene regulation, are important activators of hilE expression. These findings indicate that invasion gene expression is coregulated with motility and adherence and provide experimental evidence that the expression of these virulence phenotypes is a subset of the overall regulation of bacterial physiology.

scholarly journals Erratum: Corrigendum: Gene expression–based high-throughput screening (GE-HTS) and application to leukemia differentiation

2004 ◽  
Vol 36 (4) ◽  
pp. 427-427 ◽  
Author(s):  
K Stegmaier ◽  
K N Ross ◽  
S A Colavito ◽  
S O'Malley ◽  
B R Stockwell ◽  
...  
Keyword(s):  
Gene Expression ◽  
High Throughput ◽  
High Throughput Screening
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