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Response of Saccharomyces cerevisiae to the stimulation of lipopolysaccharide.

Shen L, Li Y, Jiang L, Wang X - PLoS ONE (2014)

Bottom Line: In this study, we found that lipopolysaccharide-treated S. cerevisiae cells could be stained by methylene blue, but did not die.Significantly regulated genes (460 up-regulated genes and 135 down-regulated genes) in lipopolysaccharide-treated S. cerevisiae cells were analyzed on Gene Ontology, and used to establish physical protein-protein interaction network and protein phosphorylation network.Based on these analyses, most of the regulated genes in lipopolysaccharide-treated S. cerevisiae cells were related to cell wall, membrane, peroxisome and mitochondrion.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China; School of Biotechnology, Jiangnan University, Wuxi, China.

ABSTRACT
Lipopolysaccharide, known as endotoxin, can stimulate potent host immune responses through the complex of Toll-like-receptor 4 and myeloid differentiation protein 2; but its influence on Saccharomyces cerevisiae, a model organism for studying eukaryotes, is not clear. In this study, we found that lipopolysaccharide-treated S. cerevisiae cells could be stained by methylene blue, but did not die. Transcriptional profiling of the lipopolysaccharide-treated S. cerevisiae cells showed that 5745 genes were modulated: 2491 genes up-regulated and 3254 genes down-regulated. Significantly regulated genes (460 up-regulated genes and 135 down-regulated genes) in lipopolysaccharide-treated S. cerevisiae cells were analyzed on Gene Ontology, and used to establish physical protein-protein interaction network and protein phosphorylation network. Based on these analyses, most of the regulated genes in lipopolysaccharide-treated S. cerevisiae cells were related to cell wall, membrane, peroxisome and mitochondrion. Further experiments demonstrated that lipopolysaccharide stimulation caused the exposure of phosphatidylserine and the increase of mitochondrial membrane potential in S. cerevisiae cells, but levels of intracellular reactive oxygen species and metacaspase activation were not increased. This study demonstrated that lipopolysaccharide stimulation causes significant changes in S. cerevisiae cells, and the results would contribute to understand the response of eukaryotic cells to lipopolysaccharide stimulation.

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Number of differentially expressed genes regulated in S. cerevisiae BY4742 cells treated with LPS (LPS+) according to transcriptome analysis.FDR stands for False Discovery Rate [51]. Log2R represents Log2 of the ratio of the gene expression difference of a gene in “LPS+” samples versus the same gene in “Control” sample.
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pone-0104428-g002: Number of differentially expressed genes regulated in S. cerevisiae BY4742 cells treated with LPS (LPS+) according to transcriptome analysis.FDR stands for False Discovery Rate [51]. Log2R represents Log2 of the ratio of the gene expression difference of a gene in “LPS+” samples versus the same gene in “Control” sample.

Mentions: To gain the insight of LPS stimulation to S. cerevisiae, the transcriptional profling of the S. cerevisiae BY4742 cells with or without LPS treatment for 90 min were analyzed [22]. The transcriptome analysis detected 5431 and 5426 genes from S. cerevisiae BY4742 cells treated with or without LPS treatment, respectively. After exposure to LPS, 2491 genes were up-regulated in S. cerevisiae BY4742 cells and 3254 genes were down-regulated, and 595 genes (460 up-regulated genes and 135 down-regulated genes) were significantly modulated (FDR ≤0.001 and /Log2R/ ≥1.0) (Fig. 2). GO analysis was performed to classify the main biological processes associated to these 595 genes. The probability values of the over-abundance of the GO groups compared to the genome average were assessed, and major GO groups with the statistical significance of overrepresented processes (p-value ≤0.05) are listed in Fig. 3. These major GO categories are closely related to cell wall, membrane, lipid, carbohydrate, and oxidation-reduction process. In the categories of antioxidant activity and lipid catabolic process, all related genes were up-regulated, while in categories of cell wall and membrane, both up-regulated and down-regulated genes were observed. These gene regulations related to cell wall and membrane might change the stability or permeability of the cell; therefore, methylene blue could penetrate and stain the cells (Fig. 1A). Regulations on cell wall, membrane, and antioxidant activity are usually related to stress response; therefore, transcriptional levels of genes in GO categories with less statistical significance (p-value >0.05) but closely related to stress responses are listed in Table S4. There are 69 genes involved in peroxisome, and 15 of them were up-regulated, suggesting that the function of peroxisome increased after LPS stimulation. Mitochondria were also affected after LPS stimulation, but more genes related to its outer membrane and intermembrane space were up-regulated than to its inner membrane (Table S4). Some genes related to protein folding, autophagy, endocytosis, and apoptosis were up-regulated after LPS stimulation, suggesting that cell injure might occur. Interestingly, 27 genes related to ribosome biogenesis were down-regulated after LPS stimulation, suggesting protein syntheses were repressed in the cells (Table S4). Autophagy usually involves degradation pathways including peroxisome degradation [10], while apoptosis always leads to cell death [3], [4]. Peroxisome and mitochondrial function are associated with antioxidant activity [36]. Apart from GO analysis, significantly enriched items of KEGG pathway also provided information about basal metabolism such as peroxisome metabolism (Fig. 3B). The data indicate that LPS stimulation caused a series of regulations in S. cerevisiae BY4742, involving cell wall, membrane, peroxisome and mitochondria.


Response of Saccharomyces cerevisiae to the stimulation of lipopolysaccharide.

Shen L, Li Y, Jiang L, Wang X - PLoS ONE (2014)

Number of differentially expressed genes regulated in S. cerevisiae BY4742 cells treated with LPS (LPS+) according to transcriptome analysis.FDR stands for False Discovery Rate [51]. Log2R represents Log2 of the ratio of the gene expression difference of a gene in “LPS+” samples versus the same gene in “Control” sample.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4126697&req=5

pone-0104428-g002: Number of differentially expressed genes regulated in S. cerevisiae BY4742 cells treated with LPS (LPS+) according to transcriptome analysis.FDR stands for False Discovery Rate [51]. Log2R represents Log2 of the ratio of the gene expression difference of a gene in “LPS+” samples versus the same gene in “Control” sample.
Mentions: To gain the insight of LPS stimulation to S. cerevisiae, the transcriptional profling of the S. cerevisiae BY4742 cells with or without LPS treatment for 90 min were analyzed [22]. The transcriptome analysis detected 5431 and 5426 genes from S. cerevisiae BY4742 cells treated with or without LPS treatment, respectively. After exposure to LPS, 2491 genes were up-regulated in S. cerevisiae BY4742 cells and 3254 genes were down-regulated, and 595 genes (460 up-regulated genes and 135 down-regulated genes) were significantly modulated (FDR ≤0.001 and /Log2R/ ≥1.0) (Fig. 2). GO analysis was performed to classify the main biological processes associated to these 595 genes. The probability values of the over-abundance of the GO groups compared to the genome average were assessed, and major GO groups with the statistical significance of overrepresented processes (p-value ≤0.05) are listed in Fig. 3. These major GO categories are closely related to cell wall, membrane, lipid, carbohydrate, and oxidation-reduction process. In the categories of antioxidant activity and lipid catabolic process, all related genes were up-regulated, while in categories of cell wall and membrane, both up-regulated and down-regulated genes were observed. These gene regulations related to cell wall and membrane might change the stability or permeability of the cell; therefore, methylene blue could penetrate and stain the cells (Fig. 1A). Regulations on cell wall, membrane, and antioxidant activity are usually related to stress response; therefore, transcriptional levels of genes in GO categories with less statistical significance (p-value >0.05) but closely related to stress responses are listed in Table S4. There are 69 genes involved in peroxisome, and 15 of them were up-regulated, suggesting that the function of peroxisome increased after LPS stimulation. Mitochondria were also affected after LPS stimulation, but more genes related to its outer membrane and intermembrane space were up-regulated than to its inner membrane (Table S4). Some genes related to protein folding, autophagy, endocytosis, and apoptosis were up-regulated after LPS stimulation, suggesting that cell injure might occur. Interestingly, 27 genes related to ribosome biogenesis were down-regulated after LPS stimulation, suggesting protein syntheses were repressed in the cells (Table S4). Autophagy usually involves degradation pathways including peroxisome degradation [10], while apoptosis always leads to cell death [3], [4]. Peroxisome and mitochondrial function are associated with antioxidant activity [36]. Apart from GO analysis, significantly enriched items of KEGG pathway also provided information about basal metabolism such as peroxisome metabolism (Fig. 3B). The data indicate that LPS stimulation caused a series of regulations in S. cerevisiae BY4742, involving cell wall, membrane, peroxisome and mitochondria.

Bottom Line: In this study, we found that lipopolysaccharide-treated S. cerevisiae cells could be stained by methylene blue, but did not die.Significantly regulated genes (460 up-regulated genes and 135 down-regulated genes) in lipopolysaccharide-treated S. cerevisiae cells were analyzed on Gene Ontology, and used to establish physical protein-protein interaction network and protein phosphorylation network.Based on these analyses, most of the regulated genes in lipopolysaccharide-treated S. cerevisiae cells were related to cell wall, membrane, peroxisome and mitochondrion.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China; School of Biotechnology, Jiangnan University, Wuxi, China.

ABSTRACT
Lipopolysaccharide, known as endotoxin, can stimulate potent host immune responses through the complex of Toll-like-receptor 4 and myeloid differentiation protein 2; but its influence on Saccharomyces cerevisiae, a model organism for studying eukaryotes, is not clear. In this study, we found that lipopolysaccharide-treated S. cerevisiae cells could be stained by methylene blue, but did not die. Transcriptional profiling of the lipopolysaccharide-treated S. cerevisiae cells showed that 5745 genes were modulated: 2491 genes up-regulated and 3254 genes down-regulated. Significantly regulated genes (460 up-regulated genes and 135 down-regulated genes) in lipopolysaccharide-treated S. cerevisiae cells were analyzed on Gene Ontology, and used to establish physical protein-protein interaction network and protein phosphorylation network. Based on these analyses, most of the regulated genes in lipopolysaccharide-treated S. cerevisiae cells were related to cell wall, membrane, peroxisome and mitochondrion. Further experiments demonstrated that lipopolysaccharide stimulation caused the exposure of phosphatidylserine and the increase of mitochondrial membrane potential in S. cerevisiae cells, but levels of intracellular reactive oxygen species and metacaspase activation were not increased. This study demonstrated that lipopolysaccharide stimulation causes significant changes in S. cerevisiae cells, and the results would contribute to understand the response of eukaryotic cells to lipopolysaccharide stimulation.

Show MeSH
Related in: MedlinePlus