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Proinflammatory Phenotype (proinflammatory + phenotype)

Distribution by Scientific Domains

Medical Sciences	80%

Selected Abstracts

Proinflammatory phenotype with imbalance of KLF2 and RelA: Risk of childhood stroke with sickle cell anemia,

AMERICAN JOURNAL OF HEMATOLOGY, Issue 1 2010
Judy Enenstein
Altered inflammation signaling within the cerebral vasculature may be an important risk factor for stroke in children with sickle cell anemia (SCA). This study examines how differential expression of NF,B/p65 (RelA), KLF2, and other transcription factors may act as switches in inflammation signaling leading to observed differences between non-SCA (NS) African Americans and African Americans with SCA who are either at risk (AR) or not at risk (NAR) of childhood stroke based on occurrence of Circle of Willis disease. Clover/Transfac analysis was used to identify overrepresented transcription factor binding motifs on genes associated with inflammation. Transcription factor binding motifs for the NF,B family and RFX1 were overrepresented on inflammation signaling gene set analysis. Variations in protein expression were determined by flow cytometry of blood outgrowth endothelial cells (BOECs) from NS, AR, and NAR donors and Western blots of protein extracts from both unstimulated and TNF,/IL1,-stimulated BOECs. BOECs from patients with SCA had more cytoplasmic-derived RelA compared with NS BOECs. Sickle BOECs also had heightened responses to inflammatory stimuli compared with NS BOECs, as shown by increased nuclear RelA, and intracellular adhesion molecule (ICAM) response to TNF,/IL1, stimulation. Multiple control points in RelA signaling were associated with risk of childhood stroke. The ratio of proinflammatory factor RelA to anti-inflammatory factor KLF2 was greater in BOECs from AR donors than NS donors. Group risk of childhood stroke with SCA was greatest among individuals who exhibited increased expression of proinflammatory transcription factors and decreased expression of transcription factors that suppress inflammation. Am. J. Hematol. 2010. © 2009 Wiley-Liss, Inc. [source]

Inhibition of Rho-dependent pathways by Clostridium botulinum C3 protein induces a proinflammatory profile in microglia

GLIA, Issue 11 2008
Anja Hoffmann
Abstract Successful regeneration in the central nervous system crucially depends on the adequate environment. Microglia as brain immune-competent cells importantly contribute to this task by producing pro- and anti-inflammatory mediators. Any environmental change transforms these cells towards an activated phenotype, leading to major morphological, transcriptional and functional alterations. Rho GTPases affect multiple cellular properties, including the cytoskeleton, and C3 proteins are widely used to study their involvement. Especially C3bot from Clostridium botulinum has been considered to promote neuronal regeneration by changing Rho activity. Yet C3bot may exert cellular influences through alternative mechanisms. To determine the role of Rho-dependent pathways in microglia we investigated the influence of C3bot on functional properties of cultivated primary mouse microglial cells. Nanomolar concentrations of C3bot transformed microglia towards an activated phenotype and triggered the release of nitric oxide and several proinflammatory cyto- and chemokines. These inductions were not mediated by the ROCK-kinase pathway, since its selective inhibitors Y27632 and H1152 had no effect. C3-induced and Rho-mediated NO release was instead found to be under the control of NF,B, as revealed by treatment with the NF,B inhibitor PDTC. Thus, C3bot induces a proinflammatory response in microglia resembling the classical proinflammatory phenotype elicited by bacterial LPS. The findings are relevant for the use of C3bot in regenerative approaches. © 2008 Wiley-Liss, Inc. [source]

Protein array technology to investigate cytokine production by monocytes from patients with advanced alcoholic cirrhosis: An ex vivo pilot study

HEPATOLOGY RESEARCH, Issue 7 2009
Khalid A. Tazi
Aim:, In patients with advanced cirrhosis, little is known about the ability of peripheral blood monocytes to spontaneously produce signaling proteins such as cytokines. The aim of this ex vivo study was to evaluate cytokine production under baseline conditions and after stimulation by lipopolysaccharide (LPS), a toll-like receptor (TLR) agonist. Methods:, Peripheral blood monocytes were isolated from patients with advanced alcoholic cirrhosis (without ongoing bacterial infections) and normal subjects. Cells were left unstimulated or were stimulated with LPS. The abundance of 24 cytokines was measured using a filter-based, arrayed sandwich enzyme-linked immunosorbent assay (ELISA) in the supernatant of cultured monocytes. Results:, Cirrhotic monocytes spontaneously produced six proteins (TNF-,, IL-6, IL-8, MCP-1, RANTES and Gro), whereas normal monocytes produced only small amounts of IL-8 and RANTES. Analyses with the online gene set analysis toolkit WebGestalt (http://bioinfo.vanderbilt.edu/webgestalt) found enrichment for the six proteins in the human gene ontology subcategory (http://www.geneontology.org), Kyoto Encyclopedia of Genes and Genome pathways (http://www.genome.ad.jp/kegg/) and BioCarta pathways (http://www.biocarta.com/genes/index.asp) consistent with a proinflammatory phenotype of cirrhotic monocytes resulting from activated TLR signaling. Interestingly, LPS-elicited TLR engagement further increased the production of the six proteins and did not induce the secretion of any others, in particular the anti-inflammatory cytokine IL-10. LPS-stimulated normal monocytes produced TNF-,, IL-6, IL-8, MCP-1, RANTES, Gro and IL-10. Conclusion:, In patients with advanced cirrhosis, peripheral blood monocytes spontaneously produce proinflammatory cytokines, presumably in response to unrestricted TLR signaling. [source]

Epitope-specific immunotherapy of rheumatoid arthritis: Clinical responsiveness occurs with immune deviation and relies on the expression of a cluster of molecules associated with T cell tolerance in a double-blind, placebo-controlled, pilot phase II trial,

ARTHRITIS & RHEUMATISM, Issue 11 2009
Eva C. Koffeman
Objective Induction of immune tolerance to maintain clinical control with a minimal drug regimen is a current research focus in rheumatoid arthritis (RA). Accordingly, we are developing a tolerization approach to dnaJP1, a peptide part of a pathogenic mechanism that contributes to autoimmune inflammation in RA. We undertook this study to test 2 hypotheses: 1) that mucosal induction of immune tolerance to dnaJP1 would lead to a qualitative change from a proinflammatory phenotype to a more tolerogenic functional phenotype, and 2) that immune deviation of responses to an inflammatory epitope might translate into clinical improvement. Methods One hundred sixty patients with active RA and with immunologic reactivity to dnaJP1 were enrolled in a pilot phase II trial. They received oral doses of 25 mg of dnaJP1 or placebo daily for 6 months. Results The dnaJP1 peptide was safe and well-tolerated. In response to treatment with dnaJP1, there was a significant reduction in the percentage of T cells producing tumor necrosis factor , and a corresponding trend toward an increased percentage of T cells producing interleukin-10. Coexpression of a cluster of molecules (programmed death 1 and its ligands) associated with T cell regulation was also found to be a prerequisite for successful tolerization in clinical responders. Analysis of the primary efficacy end point (meeting the American College of Rheumatology 20% improvement criteria at least once on day 112, 140, or 168) showed a difference between treatment groups that became significant in post hoc analysis using generalized estimating equations. Differences in clinical responses were also found between treatment groups on day 140 and at followup. Post hoc analysis showed that the combination of dnaJP1 and hydroxychloroquine (HCQ) was superior to the combination of HCQ and placebo. Conclusion Tolerization to dnaJP1 leads to immune deviation and a trend toward clinical efficacy. Susceptibility to treatment relies on the coexpression of molecules that can down-regulate adaptive immunity. [source]

Microparticles stimulate the synthesis of prostaglandin E2 via induction of cyclooxygenase 2 and microsomal prostaglandin E synthase 1

ARTHRITIS & RHEUMATISM, Issue 11 2007
Astrid Jüngel
Objective Microparticles are small vesicles that are released from activated or dying cells and that occur abundantly in the synovial fluid of patients with rheumatoid arthritis (RA). The goal of these studies was to elucidate the mechanisms by which microparticles activate synovial fibroblasts to express a proinflammatory phenotype. Methods Microparticles from monocytes and T cells were isolated by differential centrifugation. Synovial fibroblasts were cocultured with increasing numbers of microparticles. Gene expression was analyzed by real-time polymerase chain reaction and confirmed by Western blotting and enzyme immunoassay. Arachidonic acid labeled with tritium was used to study the transport of biologically active lipids by microparticles. The roles of NF-,B and activator protein 1 (AP-1) signaling were analyzed with electrophoretic mobility shift assay and transfection with small interfering RNA and I,B expression vectors. Results Microparticles strongly induced the synthesis of cyclooxygenase 2 (COX-2), microsomal prostaglandin E synthase 1 (mPGES-1), and prostaglandin E2 (PGE2). In contrast, no up-regulation of COX-1, mPGES-2, cytosolic PGES, or phospholipase A2 was observed. The induction of PGE2 was blocked by selective inhibition of COX-2. Microparticles activated NF-,B, AP-1, p38, and JNK signaling in synovial fibroblasts. Inhibition of NF-,B, AP-1, and JNK signaling reduced the stimulatory effects. Arachidonic acid was transported from leukocytes to fibroblasts by microparticles. Arachidonic acid derived from microparticles was converted to PGE2 by synovial fibroblasts. Conclusion These results demonstrate that microparticles up-regulate the production of PGE2 in synovial fibroblasts by inducing COX-2 and mPGES-1. These data provide evidence for a novel mechanism by which microparticles may contribute to inflammation and pain in RA. [source]