Interaction between the host and invading pathogen determines the fate of both organisms during the infectious state. The host is equipped with a battery of immune reactions, while the pathogen displays a variety of mechanisms to compromise host immunity. Although bacteria alter their pattern of gene expression when they enter host organisms, studies to elucidate the mechanism behind this are only in their infancy. In the present study, we examined the possibility that host immune proteins directly participate in the change of gene expression in bacteria. To this end, Escherichia coli was treated with a mixture of the extracellular region of membrane-bound peptidoglycan recognition protein LC (PGRP-LC) and the antimicrobial peptide attacin of Drosophila, and subsequently subjected to DNA microarray analysis for the repertoire of mRNA. We identified nearly 200 genes whose mRNA increased after the treatment, and at least four of them were induced in response to PGRP-LC. One such gene, lipoprotein-encoding nlpI, showed a transient increase of its mRNA level in adult flies depending on PGRP-LC, and NlpI-lacking E. coli had a smaller pathogenic effect with lowered growth/viability than the parental strain in adult flies. These results suggest that a host immune receptor triggers a change of gene expression in bacteria simultaneously to their recognition of the invader and induction of immune responses.
Peptidoglycan recognition protein-triggered induction of Escherichia coli gene in Drosophila melanogaster.
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View SamplesWakame is an edible seaweed that is a common constituent in the Japanese diet. Previous studies showed that wakame consumption is associated with prevention of metabolic syndrome; however, the molecular mechanisms of this protective effect are poorly understood. To determine if the expression of hepatic genes is affected by the ingestion of brown seaweed, Undaria pinnatifida (wakame), rats were fed diets containing 0, 0.1, or 1.0 g/100 g dried wakame powder for 28 days. Administration of 1% wakame significantly decreased total serum total cholesterol levels. Hepatic gene expression was investigated using DNA microarray analysis. Microarray analysis showed that wakame suppresses the lipogenic pathway by downregulating SREBF-1. Moreover, bile acid biosynthesis and gluconeogenesis are promoted by upregulation of the PPAR signaling pathway, which leads to a reduction in the accumulation of cholesterol and promotion of -oxidation. These results provide useful genetic information about various biochemical processes by which wakame regulates energy metabolism.
Oral Administration of Edible Seaweed Undaria Pinnatifida (Wakame) Modifies Glucose and Lipid Metabolism in Rats: A DNA Microarray Analysis.
Sex, Age, Specimen part
View SamplesThe phagocytic elimination of cells undergoing apoptosis is an evolutionarily conserved innate immune mechanism for eliminating unnecessary cells. Previous studies showed an increase in the level of engulfment receptors in phagocytes after the phagocytosis of apoptotic cells, which leads to the enhancement of their phagocytic activity. However, precise mechanisms underlying this phenomenon require further clarification. We found that the pre-incubation of a Drosophila phagocyte cell line with the fragments of apoptotic cells enhanced the subsequent phagocytosis of apoptotic cells, accompanied by an augmented expression of the engulfment receptors Draper and integrin PS3. The DNA-binding activity of the transcription repressor Tailless was transiently raised in those phagocytes, depending on two partially overlapping signal-transduction pathways for the induction of phagocytosis as well as the occurrence of engulfment. The RNAi knockdown of tailless in phagocytes abrogated the enhancement of both phagocytosis and engulfment receptor expression. Furthermore, the hemocyte-specific RNAi of tailless reduced apoptotic cell clearance in Drosophila embryos. Taken together, we propose the following mechanism for the activation of Drosophila phagocytes after an encounter with apoptotic cells: two partially overlapping signaltransduction pathways for phagocytosis are initiated; transcription repressor Tailless is activated; expression of engulfment receptors is stimulated; and phagocytic activity is enhanced. This phenomenon most likely ensures the phagocytic elimination of apoptotic cells that stimulated phagocytes find thereafter and is thus considered as a mechanism to prime phagocytes in innate immunity.
Signaling pathway for phagocyte priming upon encounter with apoptotic cells.
Cell line, Treatment, Time
View SamplesNeural precursor cells (NPCs) are multipotent cells that can generate neurons, astrocytes, and oligodendrocytes in the mammalian central nervous system. Although Zbtb20 was expressed in NPCs, its functions in neural development are not fully understood. We performed microarray analysis to examine changes in gene expression between control and Zbtb20-overexpressed NPCs.
Zbtb20 promotes astrocytogenesis during neocortical development.
Specimen part
View SamplesAnalysis of murine cardiomyocyte cell line HL-1 treated with Ivermectin or Importazole. Results provide insight into the pathways regulated by the treatments. Overall design: RNA-seq of mouse HL-1 cardiomyocytes treated with vehicle (DMSO), Ivermectin, or Importazole for 24 hours, in triplicate, using Ion Proton System.
Antihypertrophic Effects of Small Molecules that Maintain Mitochondrial ATP Levels Under Hypoxia.
Specimen part, Cell line, Treatment, Subject
View SamplesHuman mesenchymal stem cells are expected to be a useful tool for cellular therapy. We used microarrays to detail the gene expression profiles and selected candidate biomarkers that indicate the culture stage of the cells.
Gene expression profiling of human mesenchymal stem cells for identification of novel markers in early- and late-stage cell culture.
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View SamplesHuman mesenchymal stem cells (hMSCs), which are multipotent cells to differentiate into several cell types, are expected to be a useful tool for cellular therapy. In some clinical settings, hMSCs have immuno-suppressive effects for GVHD (Graft-versus-host disease) and are expanded in vitro before application. To find biomarkers that indicate the culture stage of hMSCs, we performed microarray analysis for hMSCs derived from bone marrow, using Affymetrix GeneChip Human Genome U133 Plus 2.0 (54,613 probe sets).
Gene expression profiling of human mesenchymal stem cells for identification of novel markers in early- and late-stage cell culture.
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View SamplesNeural precursor cells (NPCs) are multipotent cells that can generate neurons, astrocytes, and oligodendrocytes in the mammalian central nervous system. Although high mobility group nucleosomal binding domain 1 (HMGN1) was highly expressed in NPCs, its functions in neural development are not fully understood. We performed microarray analysis to examine changes in gene expression between control and HMGN1-overexpressed NPCs.
High mobility group nucleosome-binding family proteins promote astrocyte differentiation of neural precursor cells.
Specimen part
View SamplesThe availability of pluripotent stem cells offers the possibility of using such cells to model hepatic disease and development. With this in mind, we previously established a protocol that facilitates the differentiation of both human embryonic stem cells and induced pluritpotent cells into cells with hepatocyte characteristics. The use of highly defined culture conditions and the avoidance of feeder cells or embryoid bodies allowed synchronous and reproducible differentiation to occur. The differentiation toward a hepatocytelike fate appeared to recapitulate many of the stages normally associated with the formation of hepatocytes in vivo. In the current study we addressed the feasibility of using human pluripotent stem cells to probe the molecular mechanisms underlying human hepatocyte differentiation. We demonstrate i) that human ES cells express a number of mRNAs that characterize each stage in the differentiation process, ii) that gene expression can be efficiently depleted throughout the differentiation time course using shRNAs expressed from lentiviruses, and iii) that the nuclear hormone receptor HNF4a is essential for specification of human hepatic progenitor cells by establishing expression of the network of transcription factors that control hepatocyte cell fate.
HNF4A is essential for specification of hepatic progenitors from human pluripotent stem cells.
Specimen part, Time
View SamplesReprogrammed somatic cells offer a valuable source of pluripotent cells that have the potential to differentiate into many cells types and provide a new tool for regenerative medicine. In the present study we differentiated induced pluripotent stem cells (iPS cells) into hepatic cells. We first showed that mouse iPS cells could from a complete liver in mouse embryo (E14.5) including hepatocytes, endothelial cells, sinusoidal cells and resident macrophages. We then designed a highly efficient hepatocyte differentiation protocol using defined factors on human embryonic stem cells (ES cells). This protocol was found to generate more than 80% albumin expressing cells that show hepatic functions and express most of liver genes as shown by microarray analyses. Similar results were obtained when human iPS cells were induced to differentiate following the same procedure.
Highly efficient generation of human hepatocyte-like cells from induced pluripotent stem cells.
Specimen part, Cell line
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