Clustering ICU patients with sepsis based on the patterns of their circulating biomarkers: A secondary analysis of the CAPTAIN prospective multicenter cohort study.

peer reviewed[en] BACKGROUND: Although sepsis is a life-threatening condition, its heterogeneous presentation likely explains the negative results of most trials on adjunctive therapy. This study in patients with sepsis aimed to identify subgroups with similar immune profiles and their clinical and outcome correlates. METHODS: A secondary analysis used data of a prospective multicenter cohort that included patients with early assessment of sepsis. They were described using Predisposition, Insult, Response, Organ failure sepsis (PIRO) staging system. Thirty-eight circulating biomarkers (27 proteins, 11 mRNAs) were assessed at sepsis diagnosis, and their patterns were determined through principal component analysis (PCA). Hierarchical clustering was used to group the patients and k-means algorithm was applied to assess the internal validity of the clusters. RESULTS: Two hundred and three patients were assessed, of median age 64.5 [52.0-77.0] years and SAPS2 score 55 [49-61] points. Five main patterns of biomarkers and six clusters of patients (including 42%, 21%, 17%, 9%, 5% and 5% of the patients) were evidenced. Clusters were distinguished according to the certainty of the causal infection, inflammation, use of organ support, pro- and anti-inflammatory activity, and adaptive profile markers. CONCLUSIONS: In this cohort of patients with suspected sepsis, we individualized clusters which may be described with criteria used to stage sepsis. As these clusters are based on the patterns of circulating biomarkers, whether they might help to predict treatment responsiveness should be addressed in further studies. TRIAL REGISTRATION: The CAPTAIN study was registered on clinicaltrials.gov on June 22, 2011, # NCT01378169

Circulating biomarkers may be unable to detect infection at the early phase of sepsis in ICU patients: the CAPTAIN prospective multicenter cohort study.

PURPOSE: Sepsis and non-septic systemic inflammatory response syndrome (SIRS) are the same syndromes, differing by their cause, sepsis being secondary to microbial infection. Microbiological tests are not enough to detect infection early. While more than 50 biomarkers have been proposed to detect infection, none have been repeatedly validated. AIM: To assess the accuracy of circulating biomarkers to discriminate between sepsis and non-septic SIRS. METHODS: The CAPTAIN study was a prospective observational multicenter cohort of 279 ICU patients with hypo- or hyperthermia and criteria of SIRS, included at the time the attending physician considered antimicrobial therapy. Investigators collected blood at inclusion to measure 29 plasma compounds and ten whole blood RNAs, and-for those patients included within working hours-14 leukocyte surface markers. Patients were classified as having sepsis or non-septic SIRS blindly to the biomarkers results. We used the LASSO method as the technique of multivariate analysis, because of the large number of biomarkers. RESULTS: During the study period, 363 patients with SIRS were screened, 84 having exclusion criteria. Ninety-one patients were classified as having non-septic SIRS and 188 as having sepsis. Eight biomarkers had an area under the receiver operating curve (ROC-AUC) over 0.6 with a 95% confidence interval over 0.5. LASSO regression identified CRP and HLA-DRA mRNA as being repeatedly associated with sepsis, and no model performed better than CRP alone (ROC-AUC 0.76 [0.68-0.84]). CONCLUSIONS: The circulating biomarkers tested were found to discriminate poorly between sepsis and non-septic SIRS, and no combination performed better than CRP alone

Le gène homéotique Cdx1 (étude de sa fonction dans l'épithélium intestinal et de son potentiel oncogénique)

L homéogène Cdx1 jouerait un rôle important dans le développement embryonnaire. Chez l adulte, où son expression est restreinte à l épithélium intestinal, il induit l expression de gènes spécifiques de l épithélium. Dans cette étude, nous avons cherché à déterminer le rôle biologique de Cdx1 dans l épithélium intestinal et son potentiel oncogénique. Pour cela, nous avons développé une lignée cellulaire transgénique exprimant Cdx1 constitutivement et nous avons étudié son phénotype. Ces cellules ont les mêmes caractéristiques que les cellules transitoires des cryptes qui prolifèrent activement et commencent à migrer et à se différencier. Nous avons ensuite montré que Cdx1 induisait la transcription de PAP I un facteur mitogénique dans les cellules intestinales. Ainsi, la croissance induite par Cdx1 serait due en partie à PAP I. Puis nous avons mis en évidence que Cdx1, p53 et deux gènes cibles de p53, p21 et Bcl-2 formaient une boucle de régulation de l apoptose et de la différenciation dans les cellules intestinales. Nous avons conclu que Cdx1 était responsable de la transition des cellules souches en cellules transitoires et qu il était au centre de la régulation des mécanismes de prolifération, d apoptose et de différenciation des cellules intestinales< ;Nous avons émis l hypothèse qu une sur-expression de Cdx1 représenterait un événement important dans le processus de tumorigénèse intestinale.The Cdx1 homeobox gene is important for the embryonic development. In adulthood, where its expression is restricted to the intestinal epithelial cells, it acts as a transcription factor of specific intestinal genes. The aim of our study was to determine the role of Cdx1 in the epithelial cells and its oncogenic potential. Thus, we constructed a cell line expressing than transit/proliferative cells from the crypts that proliferate and begin to migrate and differentiate. We showed that Cdx1 induces PAP I, a mitogenic factor of intestinal cells. Growth activity of Cdx1 would be mediated in part by PAP I. Then, we defined an auto regulation loop between Cdx1, p53, and two p53-target genes, p21 and bcl-2 which could regulate apoptosis and differentiation in intestinal cells. We concluded that Cdx1 is responsible for the first differentiation step from the stem cells to transit/proliferative cells in the intestinal epithelium and that it is implicated in the regulation of apoptosis, differentiation and proliferation processes in epithelial cells. We hypothesized that an over-expression of Cdx1 would represent a major event in the tumorigenesis process of colon cancer.NICE-BU Sciences (060882101) / SudocSudocFranceF

STAT Signaling by Erythropoietin

Erythropoietin (Epo) is a 34 kDa glycoprotein hormone that controls red cell formation through promotion of survival, proliferation and differentiation of erythroid progenitors. Apart from red cell precursors, the erythropoietin receptor (EpoR) is expressed in neurons, endothelial cells and megakaryocytes. Binding of Epo to the EpoR triggers the activation of different signaling pathways by activation of Janus kinase 2 (JAK2), STAT5, STAT1 and STAT3, phosphatidylinositol (PI)-3-Kinase, modulators of Ras and MAP kinase signaling, and multiple tyrosine kinases, as reviewed in (1, 2). Regulation of STAT signaling, especially of STAT5, is a prominent cellular signaling event induced by Epo. Deregulation of STAT cellular localization and transcriptional activity has been described in a number of hematological malignancies, underscoring the importance of the STAT pathway for hematopoietic homeostasis

Differential STAT5 signaling by ligand-dependent and constitutively active cytokine receptors

Many leukemia and cancer cells exhibit constitutive activation of STAT5, which was suggested to provide an anti-apoptotic advantage. Transformation of cytokine-dependent hematopoietic cells, such as Ba/F3 cells to autonomous growth and tumorigenicity equally results in selection for constitutive activation of STAT5. We compared STAT5 signaling between erythropoietin (Epo)-dependent cells and cells that were transformed by oncogenic activation of the erythropoietin receptor (EpoR) by coexpression of the gp55-P envelope protein of the spleen focus forming virus or by expression of the R129C constitutively active EpoR mutant. In transformed cells it was mainly STAT5B that was constitutively activated. In contrast, Epo stimulation activated both STAT5A and STAT5B. In transformed cells, chromatin immunoprecipitation (ChIP) showed STAT5 to be physically bound to promoters of STAT5 target genes, such as Bcl(XL), and to be able to promote transactivation of the Bcl(XL) promoter in a constitutive fashion. Sequencing of native sequences after ChIP with anti-STAT5 antibodies in Epo-dependent and -transformed cells indicated that in gp55-transformed cells, STAT5B bound in the chromatin not only to N3 high affinity, but also to low affinity N4 GAS sites. Transactivation for N3 GAS sites in luciferase reporters was specific to gp55 transformation. Because we also found preferential constitutive STAT5B activation after transformation of cells by a truncated form of the G-CSF-R that produces severe neutropenia (Kostmann syndrome) and favors leukemia in humans, we discuss the potential role of STAT5B in oncogenic transformation of hematopoietic cells

Rôle de la région transmembranaire du récepteur de l'érythropoïétine dans la transmission du signal

[Signal transduction of the erythropoietin receptor : role of the transmembrane region

Identification of chemical inhibitors of protein-kinase CK2 subunit interaction.

International audienceProtein kinase CK2 is a multi-subunit complex whose dynamic assembly appears as a crucial point of regulation. The ability to interfere with specific protein-protein interactions has already provided powerful means of influencing the functions of selected proteins within the cell. CK2beta-derived cyclopeptides that target a well-defined hydrophobic pocket on CK2alpha have been previously characterized as potent inhibitors of CK2 subunit assembly [9]. As a first step toward the rational design of low molecular weight CK2 antagonists, we have in the present study screened a collection of podophyllotoxine indolo-analogues to identify chemical inhibitors of the CK2 subunit interaction. We report the identification of a podophyllotoxine indolo-analogue as a chemical ligand that binds to the CK2alpha/CK2beta interface inducing selective disruption of the CK2alpha/CK2beta assembly and concomitant inhibition of CK2alpha activity