The precise mechanism and effects of antibiotics in host gene expression and immunomodulation in MRSA infection is unknown. Using a well characterized Methicillin Resistant Staphylococcus aureus (MRSA) isolate USA300 in a murine model of infection, we determined that linezolid and vancomycin induced differential production of bacterial toxins and host cytokines, differences in host gene expression, and differences in immunomodulators during MRSA bloodstream infection. A total of 35 A/J mice, categorized into seven groups (no infection; no infection with linezolid; no infection with vancomycin; 2 hour post-infection (hpi) S. aureus; 24 hpi S. aureus; 24 hpi S. aureus with linezolid; and 24 hpi S. aureus with vancomycin), were used in this study. Mice were injected with USA300 (6 x 106 CFU/g via i.p. route), then intravenously treated with linezolid (25 mg/kg) or vancomycin (25 mg/kg) at 2 hpi. Control and S. aureus infected mice were euthanized at each time point (2 h or 24h) following injection. Whole blood RNA was used for microarray; three cytokines and two S. aureus toxins [PantonValentine Leukocidin (PVL) and alpha hemolysin] were quantified in mouse serum by ELISA. S. aureus CFUs were significantly reduced in blood and kidney after linezolid or vancomycin treatment in S. aureus-infected mice. In vivo IL-1 in mouse serum was significantly reduced in both linezolid (p=0.001) and vancomycin (p=0.006) treated mice compared to untreated ones. IL-6 was significantly reduced only in linezolid treated (p<0.001) but not in vancomycin treated mice. However, another proinflammatory cytokine, TNF-, did not exhibit altered levels in either linezolid or vancomycin treated mice (p=0.3 and p=0.51 respectively). In vivo level of bacterial toxin, Panton-Valentine leukocidin, in mouse serum was significantly reduced only in linezolid treated mice (p=0.02) but not in vancomycin treated mice. There was no significant effect of either treatment in in vivo level of alpha hemolysin production. Unsupervised hierarchical clustering using the gene expression data from 35 microarrays revealed distinct clustering based on infection status and treatment group. Study of the antibiotic-specific difference in gene expression identified the number of genes uniquely expressed in response to S. aureus infection, infection with linezolid treatment, and infection with vancomycin treatment. Pathway associations study for the differentially expressed genes in each comparison group (Control vs. 24 h S. aureus infection, 24 h S. aureus infection vs. 24 h S. aureus linezolid, and 24 h S. aureus infection vs. 24 h S. aureus vancomycin) in mice using Kyoto Encyclopedia of Genes and Genomes (KEGG) identified toll-like receptor signaling pathway to be common to every comparison groups studied. Glycerolipid metabolism pathway was uniquely associated only with linezolid treatment comparison group. The findings of this study provide the evidence that protein synthesis inhibitor like linezolid does a better job in treating MRSA sepsis compared to cell wall acting antibiotics like vancomycin.
Host gene expression profiling and in vivo cytokine studies to characterize the role of linezolid and vancomycin in methicillin-resistant Staphylococcus aureus (MRSA) murine sepsis model.
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View SamplesThe goal of the study was to identify the genes which are regulated by Interleukin-2 in the CD4+ T cells of the scurfy mice during regulatory T-cell deficiency. Scurfy (Sf) mice bear a mutation in the forkhead box P3 (Foxp3) transcription factor, lack regulatory T-cells (Treg), develop multi-organ inflammation, and die prematurely. The major target organs affected are skin, lungs, and liver. Sf mice lacking the Il2 gene (Sf.Il2-/-), despite devoid of Treg, did not develop skin and lung inflammation, but the inflammation in liver, pancreas, submandibular gland and colon remained. Genome-wide microarray analysis revealed hundreds of genes were differentially regulated among Sf, Sf.Il2-/-, and B6 CD4+ T-cells but the most changes were those encoding receptors for trafficking/chemotaxis/retention and lymphokines. Our study suggests that IL-2 controls the skin and lung inflammation in Sf mice in an apparent "organ-specific" manner through two novel mechanisms: by regulating the expression of genes encoding receptors for T-cell trafficking/chemotaxis/retention and by regulating Th2 cell expansion and lymphokine production. Thus, IL-2 is a master regulator for multi-organ inflammation and an underlying etiological factor for various diseases associated with skin and lung inflammation.
IL-2-controlled expression of multiple T cell trafficking genes and Th2 cytokines in the regulatory T cell-deficient scurfy mice: implication to multiorgan inflammation and control of skin and lung inflammation.
Sex, Specimen part
View SamplesAlthough it has recently been shown that A/J mice are highly susceptible to Staphylococcus aureus sepsis as compared to C57BL/6J, the specific genes responsible for this differential phenotype are unknown. Using chromosome substitution strains (CSS), we found that factors on chromosomes (chr) 8, 11, and 18 are responsible for susceptibility to S. aureus sepsis in A/J mice. F1 mice from C57BL/6J X CSS8 cross (C8A) and C57BL/6J X CSS18 (C18A) were also susceptible to S. aureus (median survival < 48 h), whereas F1 mice from C57BL/6J X CSS11 cross (C11A) were resistant (median survival > 120 h) to S. aureus. Bacterial loads in the kidney were consistent with F1 median survivals, with higher bacterial counts in susceptible mice. No sexlinked associations with susceptibility were noted in F1 intercrosses. Using whole genome transcription profiling, we identified a total of 192 genes on chromosomes 8, 11, and 18 which are differentially expressed between A/J and C57BL/6J in the setting of S. aureus infection. Of these, 28 genes had Gene Ontology annotations indicating a potential immune response function. These 28 genes are associated with susceptibility to S. aureus in A/J mice, and are potential determinants of susceptibility to S. aureus infection in humans.
Two genes on A/J chromosome 18 are associated with susceptibility to Staphylococcus aureus infection by combined microarray and QTL analyses.
Time
View SamplesFumarylacetoacetate hydrolase (Fah), the last enzyme of the tyrosine degradation pathway, is specifically expressed in hepatocytes in the liver. Loss of Fah leads to liver failure in mice within 6-8 weeks. This can be prevented by blocking tyrosine degradation upstream of Fah with 2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione (NTBC). Here, we investigate the impact of p21 on global gene expression in Fah deficiency.
Loss of p21 permits carcinogenesis from chronically damaged liver and kidney epithelial cells despite unchecked apoptosis.
No sample metadata fields
View SamplesTo understand the underlying cause for the observed apoptosis in E2f1-3 deficient myeloid cells. We compared gene expression profiles of Cd11b+ sorted myeloid cells isolated from bone marrow of control (E2F1-/- ) and experimental (Mxcre;E2F1-/-2-/-3f/f ) mice.
E2f1-3 are critical for myeloid development.
Age, Specimen part
View SamplesThe mechanisms involved in epithelium-stroma interactions remain poorly understood, despite the importance of the microenvironment during tumorigenesis. Here, we studied the role of Ets2 transcrpiton factor in tumor associated fibroblasts in the MMTV-ErbB2 mammary tumor model. Inactivation of Ets2 specifically in fibroblasts using Fsp-cre significantly reduced tumor growth, in contrast to Ets2 inactivation in epithelium in which no differences in tumor growth were observed.
Ets2 in tumor fibroblasts promotes angiogenesis in breast cancer.
Age, Specimen part
View SamplesDetermination of differential expression of genes in the thyroid of pendrin (Slc26a4) heterozygous and knockout mice at a time point corresponding to maximal thyroid gland activity, postnatal day 15 (P15).
Developmental delays consistent with cochlear hypothyroidism contribute to failure to develop hearing in mice lacking Slc26a4/pendrin expression.
No sample metadata fields
View SamplesExtensive molecular profiling of leukemias and preleukemic diseases has revealed that distinct clinical entities, like acute myeloid (AML) and T-lymphoblastic leukemia, share the same pathogenetic mutations. It is not well understood how the cell of origin, accompanying mutations, extracellular signals or structural differences in a mutated gene determine the phenotypic identity of the malignant disease. We studied the relationship of different protein domains of the MN1 oncogene and their effect on the leukemic phenotype, building on the ability of MN1 to induce leukemia without accompanying mutations. We found that the most C-terminal domain of MN1 was required to block myeloid differentiation at an early stage, and deletion of an extended C-terminal domain resulted in loss of myeloid identity and cell differentiation along the T-cell lineage in vivo. Megakaryocytic/erythroid lineage differentiation was blocked by the most N-terminal domain. In addition, the N-terminus was required for proliferation and leukemogenesis in vitro and in vivo through upregulation of HoxA9, HoxA10 and Meis2. Our results provide evidence that a single oncogene can modulate cellular identity of leukemic cells based on its active domains. It is therefore likely that different mutations in the same oncogene may impact cell fate decisions and phenotypic appearance of malignant diseases.
Cell fate decisions in malignant hematopoiesis: leukemia phenotype is determined by distinct functional domains of the MN1 oncogene.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Enhancer variants reveal a conserved transcription factor network governed by PU.1 during osteoclast differentiation.
Specimen part
View SamplesSimilar temporal expression kinetics of transcription factors in human and mouse osteoclast differentiation evaluated by microarray
Enhancer variants reveal a conserved transcription factor network governed by PU.1 during osteoclast differentiation.
Specimen part
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