Background. Infections caused by Staphylococcus aureus are associated with significant morbidity and mortality and are an increasing threat not only in hospital settings. The expression of the staphylococcal virulence factor repertoire is known to be affected by the alternative sigma factor B (SigB). However, its impact during infection still is a matter of debate. Methods. Kidney tissue of controls or mice infected with S. aureus HG001 or its isogenic sigB mutant was analyzed by transcriptome profiling to monitor the host response, and additionally expression of selected S. aureus genes was monitored by RT-qPCR. Results. Direct transcript analysis by RT-qPCR revealed significant SigB activity in all mice infected with the wild type strain (WT), but not in its isogenic sigB mutant (p<0.0001). Despite a clear cut difference in the SigB-dependent transcription pattern of virulence genes (clfA, aur, and hla), the host reaction to infection (either WT or sigB mutant) was almost identical. Conclusions. Despite its significant activity in vivo, loss of SigB did not have an effect on the outcome of infection as well as on murine kidney gene expression pattern. Thus, these data support the role of SigB as virulence modulator rather than being a virulence determinant by itself.
The alternative sigma factor B modulates virulence gene expression in a murine Staphylococcus aureus infection model but does not influence kidney gene expression pattern of the host.
Sex, Specimen part
View SamplesThe species Staphylococcus (S.) aureus harbors 19 superantigen gene loci, six of which are located in the enterotoxin gene cluster (egc). While these egc superantigens are far more prevalent in clinical S. aureus isolates than non-egc superantigens, they are not a prominent cause of toxic shock. Moreover, neutralizing antibodies against egc superantigens are very rare, even among carriers of egc-positive S. aureus strains. In search of an explanation we have tested two non-exclusive hypotheses: 1) egc and non-egc superantigens have unique intrinsic properties and drive the immune system into different directions; 2) egc and non-egc-superantigens are released by S. aureus under different conditions, which shape the immune response.
Immune cell activation by enterotoxin gene cluster (egc)-encoded and non-egc superantigens from Staphylococcus aureus.
No sample metadata fields
View SamplesStress is a powerful modulator of neuroendocrine, behavioral and immunological functions. After 4.5 days of repeated combined acoustic and restraint stress as a murine model of chronic psychological stress severe metabolic dysregulations became detectable in female BALB/c mice. Stress-induced alterations of metabolic processes that were found in a hepatic mRNA expression profiling were verified by in vivo analyses. Repeatedly stressed mice developed a hypermetabolic syndrome with severe loss of lean body mass, hyperglycemia, dyslipidemia, increased amino acid turn-over, and acidosis. This was associated with hypercortisolism, hyperleptinemia, insulin resistance, and hypothyroidism. In contrast, after a single acute stress exposure changes in expression of metabolic genes were much less pronounced and predominantly confined to gluconeogenesis, probably indicating that metabolic disturbances might be initiated already early but will only manifest in repeatedly stressed mice .Thus, in our murine model, repeated stress caused severe metabolic dysregulations leading to a drastic reduction of the individual's energy reserves. Under such circumstances stress may further reduce the ability to cope with new stressors such as infection or cancer.
Hypermetabolic syndrome as a consequence of repeated psychological stress in mice.
Sex, Age
View SamplesStress is a powerful modulator of neuroendocrine, behavioral and immunological functions. After 4.5 days of repeated combined acoustic and restraint stress as a murine model of chronic psychological stress severe metabolic dysregulations became detectable in female BALB/c mice. Stress-induced alterations of metabolic processes that were found in a hepatic mRNA expression profiling were verified by in vivo analyses. Repeatedly stressed mice developed a hypermetabolic syndrome with severe loss of lean body mass, hyperglycemia, dyslipidemia, increased amino acid turn-over, and acidosis. This was associated with hypercortisolism, hyperleptinemia, insulin resistance, and hypothyroidism. In contrast, after a single acute stress exposure changes in expression of metabolic genes were much less pronounced and predominantly confined to gluconeogenesis, probably indicating that metabolic disturbances might be initiated already early but will only manifest in repeatedly stressed mice .Thus, in our murine model, repeated stress caused severe metabolic dysregulations leading to a drastic reduction of the individual's energy reserves. Under such circumstances stress may further reduce the ability to cope with new stressors such as infection or cancer.
Hypermetabolic syndrome as a consequence of repeated psychological stress in mice.
Sex, Age
View SamplesStress is a powerful modulator of neuroendocrine, behavioral and immunological functions. After 4.5 days of repeated combined acoustic and restraint stress as a murine model of chronic psychological stress severe metabolic dysregulations became detectable in female BALB/c mice. Stress-induced alterations of metabolic processes that were found in a hepatic mRNA expression profiling were verified by in vivo analyses. Repeatedly stressed mice developed a hypermetabolic syndrome with severe loss of lean body mass, hyperglycemia, dyslipidemia, increased amino acid turn-over, and acidosis. This was associated with hypercortisolism, hyperleptinemia, insulin resistance, and hypothyroidism. In contrast, after a single acute stress exposure changes in expression of metabolic genes were much less pronounced and predominantly confined to gluconeogenesis, probably indicating that metabolic disturbances might be initiated already early but will only manifest in repeatedly stressed mice .Thus, in our murine model, repeated stress caused severe metabolic dysregulations leading to a drastic reduction of the individual's energy reserves. Under such circumstances stress may further reduce the ability to cope with new stressors such as infection or cancer.
Hypermetabolic syndrome as a consequence of repeated psychological stress in mice.
Sex, Age
View SamplesABSTRACT
Increased expression of bcl11b leads to chemoresistance accompanied by G1 accumulation.
No sample metadata fields
View SamplesSurgical glaucoma therapy is characterized by implantation of an aqueous shunt either draining into the extraocular Tenons space or the intraocular suprachoroidal space. In both cases the long term drainage is hampered by fibrotic reactions around the outflow region of the shunt. The prevention of fibrosis should extend the operating life of the shunt. For an aqueous shunt draining from the anterior chamber into the choroidal space fibroblasts from the choroidea and/or the sclera are most likely responsible for a fibrotic response around the outflow region of such a shunt. A detailed characterization of fibroblasts derived from choroidea and sclera should provide information whether a fibrosis reaction can be inhibited by cell type specific agents. Therefore, we have decided to generate mRNA profiles of fibroblasts from the choroidea, sclera and Tenons space in order to look for potential pharmacological targets for fibrosis prevention. The three fibroblast types investigated share fibroblast specific gene expression patterns, concerning extracellular matrix proteins as collagens and fibronectin, but also show distinct mRNA patterns, which we plan to search for targets responsible for fibrotic processes which hopefully can be targeted by specific antifibrotic drugs.
No associated publication
Specimen part
View SamplesResponsiveness of cells to alpha-toxin (Hla) from Staphylococcus aureus appears to occur in a cell-type dependent manner. Here, we compare two human bronchial epithelial cell lines, i.e. Hla-susceptible 16HBE14o- and Hla-resistant S9 cells, by a quantitative multi-omics strategy for a better understanding of Hla-induced cellular programs. Phosphoproteomics revealed a substantial impact on phosphorylation-dependent signaling in both cell models and highlights alterations in signaling pathways associated with cell-cell and cell-matrix contacts as well as the actin cytoskeleton as key features of early rHla-induced effects. Along comparable changes in down-stream activity of major protein kinases significant differences between both models were found upon rHla-treatment including activation of EGFR and MAPK1/3 signaling in S9 and repression in 16HBE14o- cells. System-wide transcript and protein expression profiling indicate induction of an immediate early response in either model. In addition, EGFR and MAPK1/3-mediated changes in gene expression suggest cellular recovery and survival in S9 cells but cell death in 16HBE14o- cells. Strikingly, inhibition of the EGFR sensitized S9 cells to Hla indicating that the cellular capacity of activation of the EGFR is a major protective determinant against Hla-mediated cytotoxic effects.
A multi-omics approach identifies key hubs associated with cell type-specific responses of airway epithelial cells to staphylococcal alpha-toxin.
Cell line
View SamplesMalignant gliomas are characterized by marked neovascularization and increased tumor cell proliferation. Recently, membrane alanyl-aminopeptidase (CD13/APN) has been identified to play a crucial role in neoangiogenesis. In this study, we show that among various central nervous system tumors, malignant astrocytomas are unique in their high expression levels of functionally active CD13/APN. CD13/APN was found in both tumor cells and tumor vessels of malignant astrocytomas, while in low-grade astrocytomas only endothelial cells of tumor vessels expressed CD13/APN. Inhibitors of the enzymatic activity of CD13/APN significantly reduced the proliferation of U87MG and U138MG malignant glioma cells. Inhibition of CD13/APN mRNA expression by siRNA in glioma cells co-cultured with human umbilical vein endothelial cells (HUVEC) effectively decreased blood vessel formation. Pro-angiogenic factors like bFGF and VEGF induced CD13/APN expression in glioma cells. Treatment of U87MG and U138MG cells with CD13/APN inhibitors resulted in an increased mRNA expression of VEGF and VEGF receptor 2 (VEGF-R2) in these cells. Taken together, these findings provide evidence that CD13/APN promotes tumor cell proliferation and blood vessel formation in malignant astrocytomas. Remarkably, inhibition of CD13/APN induces an angiogenic expression profile via an autocrine feed-back mechanism involving the VEGF/VEGF-R2 system in malignant gliomas.
No associated publication
Specimen part
View SamplesABSTRACT
Bone marrow-derived macrophages from BALB/c and C57BL/6 mice fundamentally differ in their respiratory chain complex proteins, lysosomal enzymes and components of antioxidant stress systems.
Treatment
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