The rapid development in septic patients of features of marked immunosuppression associated with increased risk of nosocomial infections and mortality represents the rational for the initiation of immune targeted treatments in sepsis. However, as there is no clinical sign of immune dysfunctions, the current challenge is to develop biomarkers that will help clinicians identify the patients that would benefit from immunotherapy and monitor its efficacy. Using an in vitro model of endotoxin tolerance (ET), a pivotal feature of sepsis-induced immunosuppression in monocytes, we identified using gene expression profiling by microarray a panel of transcripts associated with the development of ET which expression was restored after immunostimulation with interferon-gamma (IFN-). These results were confirmed by qRT-PCR. Importantly, this short-list of markers was further evaluated in patients. Of these transcripts, six (TNFAIP6, FCN1, CXCL10, GBP1, CXCL5 and PID1) were differentially expressed in septic shock patients blood compared to healthy blood upon ex vivo LPS stimulation and were restored by IFN-. In this study, by combining a microarray approach in an in vitro model and a validation in clinical samples, we identified a panel of six transcripts that could be used for the identification of septic patients eligible for IFNg therapy. The potential value of these markers should now be evaluated in a larger cohort of patients. Upon favorable results, they could serve as stratification tools prior to immunostimulatory treatment and to monitor drug efficacy.
Identification of biomarkers of response to IFNg during endotoxin tolerance: application to septic shock.
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LEAFY target genes reveal floral regulatory logic, cis motifs, and a link to biotic stimulus response.
Specimen part
View SamplesThe transition from vegetative growth to flower formation is critical for the survival of flowering plants. The plant-specific transcription factor LEAFY (LFY) has central, evolutionarily conserved roles in this process, both in the formation of the first flower and later in floral patterning. We performed genome-wide binding and expression studies to elucidate the molecular mechanisms by which LFY executes these roles. Our study reveals that LFY directs an intricate regulatory network in control of floral homeotic gene expression and, unexpectedly, controls the expression of genes regulating the response to external stimuli in Arabidopsis. We further show that LFY dampens responses to a bacterial MAMP (microbe-associated molecular pattern) and to pathogen challenge. Our findings suggest a molecular mechanism for the coordination of reproductive stage development and disease response programs in plants. Regulation of these distinct survival programs by a single transcription factor may ensure optimal allocation of plant resources for reproductive fitness.
LEAFY target genes reveal floral regulatory logic, cis motifs, and a link to biotic stimulus response.
Specimen part
View SamplesWe used oligonucleotide microarrays to address the specificities of transcriptional responses of adult Drosophila to different stresses induced by paraquat and H2O2, two oxidative stressors, and by tunicamycin which induces an endoplasmic reticulum (ER) stress. Flies were tested 24 hours after exposure to continuous stresses induced by ingestion of paraquat, H2O2 or tunicamycin at concentrations leading to similar effects on viability. We used concentrations of 1% H2O2, 5mM paraquat and 12uM of tunicamycin which lead to negligeable mortality at 24 hours. A paraquat concentration of 15mM was also used for comparison with previous studies Both specific and common responses to the three stressors were observed and whole genome functional analysis identified several important classes of stress responsive genes. Within some functional classes, we observed large variabilities of transcriptional changes between isozymes, which may reflect unsuspected functional specificities.
Genome wide analysis of common and specific stress responses in adult drosophila melanogaster.
Sex, Age, Compound, Time
View SamplesAlternative splicing of pre-mRNA generates protein diversity and has been linked to cancer progression and drug response. Exon microarray technology enables genome-wide quantication of expression levels for the majority of exons and facilitates the discovery of alternative splicing events. Analysis of exon array data is more challenging than gene expression data and there is a need for reliable quantication of exons and alternative spliced variants. We introduce a novel, computationally efficient methodology, MEAP, for exon array data preprocessing, analysis and visualization. We compared MEAP with other preprocessing methods, and validation of the results show that MEAP produces reliable quantication of exons and alternative spliced variants. Analysis of data from head and neck squamous cell carcinoma (HNSCC) cell lines revealed several variants associated with 11q13 amplication, which is a predictive marker of metastasis and decreased survival in HNSCC patients. Together these results demonstrate the utility of MEAP in suggesting novel experimentally testable predictions. Thus, in addition to novel methodology to process large-scale exon array data sets, our results provide several HNSCC candidate genes for further studies.
Comprehensive exon array data processing method for quantitative analysis of alternative spliced variants.
Cell line
View SamplesRadiotherapy is widely used to treat human cancer. Patients locally recurring after radiotherapy, however, have increased risk of metastatic progression and poor prognosis. The clinical management of post-radiation recurrences remains an unresolved issue. Tumors growing in pre-irradiated tissues have an increased fraction of hypoxic cells and are more metastatic, a condition known as tumor bed effect. Here we demonstrate that tumor cells growing in a pre-irradiated bed, or selected in vitro though repeated cycles of severe hypoxia, retain an invasive and metastatic capacities when returned to normoxia. HIF activity, while it facilitates metastatic spreading of tumors growing in a pre-irradiated bed, is not essential. Through gene expression profiling and gain and loss of function experiments, we identified the matricellular protein CYR61 and aVb5 integrin, as proteins cooperating to mediate these effects. Inhibition of aVb5 integrin suppressed invasion and metastasis induced by CYR61 and attenuated metastasis of tumors growing within a pre-irradiated field. These results represent a conceptual advance to the understanding of the tumor bed effect and identify CYR61 and aVb5 integrin as proteins that co-operate to mediate metastasis. They also indicate aV integrin inhibition a potential therapeutic approach for preventing metastasis in patients at risk for post-radiation recurrences, which can be promptly tested in the clinic.
CYR61 and alphaVbeta5 integrin cooperate to promote invasion and metastasis of tumors growing in preirradiated stroma.
No sample metadata fields
View SamplesType I interferon (IFN) is a family of 15 cytokines (in human 13, 1,1) which exert several cellular functions through the binding to a common receptor. Despite the initial activation of the same Jak/Stat signalling pathway, the cellular response may be different depending on the type I IFN subtype. We investigated the activity of different type I IFN subtypes - IFN1, 2, 8, 21, and - on the differentiation of DC. Transcriptome analyses identified two distinct groups, the IFN/-DC and the IFN-DC. 78 genes, 7 chemokines and expression levels of cell surface markers characteristic of DC distinguished IFN-DC and IFN-DC. These differences are unlikely to impact the efficacy of T cell functional response since IFN2-DC and IFN-DC were equipotent in inducing the proliferation and the polarization of allogenic nave CD4 T cells into Th1 cells and in stimulating autologous memory CD4 or CD8 T cells. In contrast, IFN2-DC were found to be more efficient than IFN-DC in the phagocytic uptake of dead cells.
Differential activity of type I interferon subtypes for dendritic cell differentiation.
No sample metadata fields
View SamplesRationale: Despite shortening vasopressor use in shock, hydrocortisone administration remains controversial, with potential harm on the immune system. Few studies assessed hydrocortisone impact on the transcriptional response in shock, and we are lacking data in burns. Objectives: To assess the hydrocortisone-induced transcriptional modulation in severe burn shock, particularly on the immune response. Methods: We collected whole blood samples (n= 117) during a randomized controlled trial assessing the efficacy of hydrocortisone administration on burn shock. Using whole genome microarrays, we first compared burn patients from the placebo group (n=15) to healthy volunteers (n=13) to describe the transcriptional modulation induced by burn shock over the first week. Then we compared burn patients randomized for either hydrocortisone administration (n=15) or placebo (n=15) to assess hydrocortisone-induced modulation. Measurements and Main Results: Study groups were similar in terms of severity and major outcomes, but shock duration (significantly reduced in the hydrocortisone group). Many genes (n=2250) were differentially expressed between burn patients and healthy volunteers, with 85% of them exhibiting a profound and persistent modulation over seven days. Interestingly, we showed that hydrocortisone enhanced the shock-associated repression of adaptive, but also innate immunity. Conclusions: We found that the initial host response to burn shock encompasses a wide and persistent modulation of gene expression, with profound modulation of pathways associated with metabolism and immunity. Importantly, hydrocortisone administration may worsen the immunosuppression associated with severe injury. These data should be taken into account in the risk ratio of hydrocortisone administration in patients with inflammatory shock.
Transcriptome modulation by hydrocortisone in severe burn shock: ancillary analysis of a prospective randomized trial.
Sex, Age, Specimen part, Disease, Treatment, Subject
View SamplesGene expression in human umbilical vein endothelial cells (HUVEC) was investigated by microarray analysis after 4 h infection with S. aureus isolated from healthy nasal carriers (n=5) and from blood (n=5) of septic patients. All bacterial isolates were spa-typed and characterized with a DNA microarray to determine the presence of virulence genes.
Staphylococcus aureus isolates from blood and anterior nares induce similar innate immune responses in endothelial cells.
Specimen part
View SamplesSeptic shock is the most severe complication of sepsis, associated with high mortality. The patient's response to supportive therapy is very heterogeneous and the underlying mechanisms are still elusive. In order to identify which are the actors (genes and pathways) that play a role in establishing the response, we investigate the whole blood transcriptome in septic shock patients with positive and negative responses to early supportive hemodynamic therapy, assessed by changes in SOFA scores within the first 48 hours from ICU admission. We pinpointed genes and pathways that are differently modulated and enriched respectively within 48hrs between responders and non-responders. Overall design: We analyzed 31 patients (17 Responders and 14 Not Responders to early therapy). For each patient, 2 samples were collected. In particular the first sample (T1) collected within 16 hours from ICU admission whereas the second (T2) collected within 48 hours from ICU admission. Experimental groups (Responders and Not Responders) are defined accordingly with SOFA scores improvements within 48 hours.
Identification of a transcriptome profile associated with improvement of organ function in septic shock patients after early supportive therapy.
Specimen part, Subject, Time
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