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Reporter Cells (reporter + cell)
Selected AbstractsAssociation of the response to tumor necrosis factor antagonists with plasma type I interferon activity and interferon-,/, ratios in rheumatoid arthritis patients: A post hoc analysis of a predominantly Hispanic cohortARTHRITIS & RHEUMATISM, Issue 2 2010Clio P. Mavragani Objective Despite the substantial clinical efficacy of tumor necrosis factor , (TNF,) antagonist therapy in patients with rheumatoid arthritis (RA), some patients respond poorly to such agents. Since an interferon (IFN) signature is variably expressed among RA patients, we investigated whether plasma type I IFN activity might predict the response to TNF antagonist therapy. Methods RA patients (n = 35), the majority of whom were Hispanic, from a single center were evaluated before and after initiation of TNF antagonist therapy. As controls, 12 RA patients from the same center who were not treated with a TNF antagonist were studied. Plasma type I IFN activity was measured using a reporter cell assay, and disease status was assessed using the Disease Activity Score in 28 joints (DAS28). Levels of interleukin-1 receptor antagonist (IL-1Ra) were determined in baseline plasma samples using a commercial enzyme-linked immunosorbent assay. The clinical response was classified according to the European League Against Rheumatism criteria for improvement in RA. Results Plasma type I IFN activity at baseline was significantly associated with clinical response (odds ratio 1.36 [95% confidence interval 1.05,1.76], P = 0.020), with high baseline IFN activity associated with a good response. Changes in DAS28 scores were greater among patients with a baseline plasma IFN,/, ratio >0.8 (indicating elevated plasma IFN, levels). Consistent with the capacity of IFN, to induce IL-1Ra, elevated baseline IL-1Ra levels were associated with better therapeutic outcomes (odds ratio 1.82 [95% confidence interval 1.1,3.29], P = 0.027). Conclusion The plasma type I IFN activity, the IFN,/, ratio, and the IL-1Ra level were predictive of the therapeutic response in TNF antagonist,treated RA patients, indicating that these parameters might define clinically meaningful subgroups of RA patients with distinct responses to therapeutic agents. [source] Genetic variation at the IRF7/PHRF1 locus is associated with autoantibody profile and serum interferon-, activity in lupus patientsARTHRITIS & RHEUMATISM, Issue 2 2010Rafah Salloum Objective Interferon-, (IFN,) is a heritable risk factor for systemic lupus erythematosus (SLE). Genetic variation near IRF7 is implicated in SLE susceptibility. SLE-associated autoantibodies can stimulate IFN, production through the Toll-like receptor/IRF7 pathway. This study was undertaken to determine whether variants of IRF7 act as risk factors for SLE by increasing IFN, production and whether autoantibodies are important to this phenomenon. Methods We studied 492 patients with SLE (236 African American, 162 European American, and 94 Hispanic American subjects). Serum levels of IFN, were measured using a reporter cell assay, and single-nucleotide polymorphisms (SNPs) in the IRF7/PHRF1 locus were genotyped. Results In a joint analysis of European American and Hispanic American subjects, the rs702966 C allele was associated with the presence of anti,double-stranded DNA (anti-dsDNA) antibodies (odds ratio [OR] 1.83, P = 0.0069). The rs702966 CC genotype was only associated with higher serum levels of IFN, in European American and Hispanic American patients with anti-dsDNA antibodies (joint analysis P = 4.1 × 10,5 in anti-dsDNA,positive patients and P = 0.99 in anti-dsDNA,negative patients). In African American subjects, anti-Sm antibodies were associated with the rs4963128 SNP near IRF7 (OR 1.95, P = 0.0017). The rs4963128 CT and TT genotypes were associated with higher serum levels of IFN, only in African American patients with anti-Sm antibodies (P = 0.0012). In African American patients lacking anti-Sm antibodies, an effect of anti-dsDNA,rs702966 C allele interaction on serum levels of IFN, was observed, similar to the other patient groups (overall joint analysis P = 1.0 × 10,6). In European American and Hispanic American patients, the IRF5 SLE risk haplotype showed an additive effect with the rs702966 C allele on IFN, level in anti-dsDNA,positive patients. Conclusion Our findings indicate that IRF7/PHRF1 variants in combination with SLE-associated autoantibodies result in higher serum levels of IFN,, providing a biologic relevance for this locus at the protein level in human SLE in vivo. [source] Elevated serum interferon-, activity in juvenile dermatomyositis: Associations with disease activity at diagnosis and after thirty-six months of therapyARTHRITIS & RHEUMATISM, Issue 6 2009Timothy B. Niewold Objective Interferon-, (IFN,) has been implicated in the pathogenesis of juvenile dermatomyositis (DM). The aim of this study was to examine serum IFN, activity in a cohort of children with juvenile DM to determine relationships between IFN, and indicators of disease activity and severity. Methods Thirty-nine children with definite/probable juvenile DM were included in the study. Serum samples were obtained at the time of diagnosis from 18 untreated patients with juvenile DM. Second samples from 11 of these patients were obtained at 24 months, while they were receiving treatment, and third samples were obtained from 7 of these patients at 36 months. The remaining 21 children were studied 36 months after their initial diagnosis. Serum IFN, activity was measured using a functional reporter cell assay. Results Patients with juvenile DM had higher serum IFN, activity than both pediatric and adult healthy control subjects. In untreated patients, serum IFN, activity was positively correlated with serum muscle enzyme levels (P < 0.05 for creatine kinase, aspartate aminotransferase, and aldolase) and inversely correlated with the duration of untreated disease (P = 0.017). The tumor necrosis factor , ,308A allele was associated with higher serum IFN, levels only in untreated patients (P = 0.030). At 36 months, serum IFN, levels were inversely correlated with muscle enzyme levels in those patients still requiring therapy and with the skin Disease Activity Score in those patients who had completed therapy (P = 0.002). Conclusion Serum IFN, activity was associated with higher serum levels of muscle-derived enzymes and a shorter duration of untreated disease in patients with newly diagnosed juvenile DM and was inversely correlated with measures of chronic disease activity at 36 months postdiagnosis. These data suggest that IFN, could play a role in disease initiation in juvenile DM. [source] The PTPN22 C1858T polymorphism is associated with skewing of cytokine profiles toward high interferon-, activity and low tumor necrosis factor , levels in patients with lupusARTHRITIS & RHEUMATISM, Issue 9 2008Silvia N. Kariuki Objective The C1858T polymorphism in PTPN22 has been associated with the risk of systemic lupus erythematosus (SLE) as well as multiple other autoimmune diseases. We have previously shown that high serum interferon-, (IFN,) activity is a heritable risk factor for SLE. The aim of this study was to determine whether the PTPN22 risk variant may shift serum cytokine profiles to higher IFN, activity, resulting in risk of disease. Methods IFN, was measured in 143 patients with SLE, using a functional reporter cell assay, and tumor necrosis factor , (TNF,) was measured by enzyme-linked immunosorbent assay. The rs2476601 single-nucleotide polymorphism in PTPN22 (C1858T) was genotyped in the same patients. Patients were grouped, using a clustering algorithm, into 4 cytokine groups (IFN, predominant, IFN, and TNF, correlated, TNF, predominant, and both IFN, and TNF, low). Results SLE patients carrying the risk allele of PTPN22 had higher serum IFN, activity than patients lacking the risk allele (P = 0.027). TNF, levels were lower in carriers of the risk allele (P = 0.030), and the risk allele was more common in patients in the IFN,-predominant and IFN, and TNF,-correlated groups as compared with patients in the TNF,-predominant and both IFN, and TNF,-low groups (P = 0.001). Twenty-five percent of male patients carried the risk allele, compared with 10% of female patients (P = 0.024); however, cytokine skewing was similar in both sexes. Conclusion The autoimmune disease risk allele of PTPN22 is associated with skewing of serum cytokine profiles toward higher IFN, activity and lower TNF, levels in vivo in patients with SLE. This serum cytokine pattern may be relevant in other autoimmune diseases associated with the PTPN22 risk allele. [source] Age- and sex-related patterns of serum interferon-, activity in lupus familiesARTHRITIS & RHEUMATISM, Issue 7 2008Timothy B. Niewold Objective Interferon-, (IFN,) levels are elevated in many patients with systemic lupus erythematosus (SLE) and may play a primary role in its pathogenesis. The purpose of this study was to determine whether serum IFN, activity in SLE patients and their healthy first-degree relatives is highest in early adulthood, when the incidence of SLE is greatest. Methods Serum samples from 315 SLE patients, 359 healthy first-degree relatives, and 141 healthy unrelated donors were measured for IFN, activity using a functional reporter cell assay. IFN, activity was analyzed in relation to age, and subgroups with high levels of IFN, activity were identified within the large data sets using a Mann-Whitney sliding window segmentation algorithm. The significance of each subgrouping was ranked by Kruskal-Wallis testing. Results Age was inversely correlated with IFN, activity in female SLE patients (r = ,0.20, P = 0.001) as well as their healthy female first-degree relatives (r = ,0.16, P = 0.02). In male patients and their healthy male first-degree relatives, there was no significant overall correlation between age and serum IFN, activity. The segmentation algorithm revealed significantly increased IFN, activity between the ages of 12 and 22 years in female SLE patients and between the ages of 16 and 29 years in male SLE patients. Both male and female healthy first-degree relatives had significantly decreased IFN, activity after the age of 50 years. Conclusion Serum IFN, activity is higher in younger individuals in the SLE family cohorts, and this tendency is accentuated in affected individuals. This age-related pattern of IFN, activity may contribute to the increased incidence of SLE in early adulthood, and interestingly, males and females had similar age-related patterns of IFN, activity. [source] Released nucleotides amplify the cilium-dependent, flow-induced [Ca2+]i response in MDCK cellsACTA PHYSIOLOGICA, Issue 3 2009H. A. Praetorius Abstract Aim:, Changes in perfusate flow produce increases in [Ca2+]i in renal epithelial cells. Cultured renal epithelia require primary cilia to sense subtle changes in flow. In perfused kidney tubules this flow response is caused by nucleotide signalling via P2Y2 receptors. It is, however, not known whether nucleotides are released by mechanical stress applied to renal primary cilia. Here we investigate whether nucleotides are released during the cilium-dependent flow response and contribute to the flow-induced, cilium-dependent [Ca2+]i signal. Methods:, MDCK cells loaded with Fluo-4-AM were observed at 37 °C in semi-open single or closed-double perfusion chambers. Results:, Our data suggest a purinergic component of the cilium-dependent flow-response: (1) ATP scavengers and P2 receptor antagonists reduced (55%) the cilium-dependent flow-response; (2) ATP added at subthreshold concentration sensitized the renal epithelia to flow changes; (3) increases in fluid flow transiently enhanced the ATP concentration in the superfusate (measured by biosensor-cells). To test if nucleotides were released in sufficient quantities to stimulate renal epithelia we used non-confluent MDCK cells without cilia as reporter cells. We confirmed that non-confluent cells do not respond to changes in fluid flow. Placing confluent, ciliated cells upstream in the in-flow path of the non-confluent cells made them responsive to fluid flow changes. This phenomenon was not observed if either non-confluent or de-ciliated confluent cells were placed upstream. The [Ca2+]i -response in the non-confluent cells with ciliated cells upstream was abolished by apyrase and suramin. Conclusion:, This suggests that subtle flow changes sensed by the primary cilium induces nucleotide release, which amplifies the epithelial [Ca2+]i -response. [source] Electroaddressing of Cell Populations by Co-Deposition with Calcium Alginate HydrogelsADVANCED FUNCTIONAL MATERIALS, Issue 13 2009Xiao-Wen Shi Abstract Electroaddressing of biological components at specific device addresses is attractive because it enlists the capabilities of electronics to provide spatiotemporally controlled electrical signals. Here, the electrodeposition of calcium alginate hydrogels at specific electrode addresses is reported. The method employs the low pH generated at the anode to locally solubilize calcium ions from insoluble calcium carbonate. The solubilized Ca2+ can then bind alginate to induce this polysaccharide to undergo a localized sol-gel transition. Calcium alginate gel formation is shown to be spatially controlled in the normal and lateral dimensions. The deposition method is sufficiently benign that it can be used to entrap the bacteria E. coli. The entrapped cells are able to grow and respond to chemical inducers in their environment. Also, the entrapped cells can be liberated from the gel network by adding sodium citrate that can compete with alginate for Ca2+ binding. The capabilities of calcium alginate electrodeposition is illustrated by entrapping reporter cells that can recognize the quorum sensing autoinducer 2 (AI-2) signaling molecule. These reporter cells were observed to recognize and respond to AI-2 generated from an external bacterial population. Thus, calcium alginate electrodeposition provides a programmable method for the spatiotemporally controllable assembly of cell populations for cell-based biosensing and for studying cell-cell signaling. [source] Development of an in vitro cell culture model of hepatic steatosis using hepatocyte-derived reporter cells,BIOTECHNOLOGY & BIOENGINEERING, Issue 5 2009Amol V. Janorkar Abstract Fatty liver disease is a problem of growing clinical importance due to its association with the increasingly prevalent conditions of obesity and diabetes. While steatosis represents a reversible state of excess intrahepatic lipid, it is also associated with increased susceptibility to oxidative and cytokine stresses and progression to irreversible hepatic injury characterized by steatohepatitis, cirrhosis, and malignancy. Currently, the molecular mechanisms underlying progression of this dynamic disease remain poorly understood, particularly at the level of transcriptional regulation. We recently constructed a library of stable monoclonal green fluorescent protein (GFP) reporter cells that enable transcriptional regulation to be studied dynamically in living cells. Here, we adapt the reporter cells to create a model of steatosis that will allow investigation of transcriptional dynamics associated with the development of steatosis and the response to subsequent "second hit" stresses. The reporter model recapitulates many cellular features of the human disease, including fatty acid uptake, intracellular triglyceride accumulation, increased reactive oxygen species accumulation, decreased mitochondrial membrane potential, increased susceptibility to apoptotic cytokine stresses, and decreased proliferation. Finally, to demonstrate the utility of the reporter cells for studying transcriptional regulation, we compared the transcriptional dynamics of nuclear factor ,B (NF,B), heat shock response element (HSE), and glucocorticoid response element (GRE) in response to their classical inducers under lean and fatty conditions and found that intracellular lipid accumulation was associated with dose-dependent impairment of NF,B and HSE but not GRE activation. Thus, steatotic reporter cells represent an efficient model for studying transcriptional responses and have the potential to provide important insights into the progression of fatty liver disease. Biotechnol. Bioeng. 2009;102: 1466,1474. © 2008 Wiley Periodicals, Inc. [source] pH and nitric oxide synthase activity and expression in bovine aortic endothelial cellsACTA PAEDIATRICA, Issue 7 2006Sandor Nagy Abstract Aim: Nitric oxide (NO) plays an important role in the transition from intrauterine to extrauterine life. If this transition fails, a condition called persistent pulmonary hypertension of the neonate (PPHN) may develop. The current treatment modalities for this disease include induction of alkalosis by hyperventilation or alkali infusion, inhaled nitric oxide (iNO) and extracorporeal membrane oxygenation. There is evidence from animal studies that the elevated pH, not the low pCO2 is responsible for the resultant pulmonary vasodilatation. In this study, we examined the effect of pH on the activity and expression of endothelial nitric oxide synthase (eNOS) in cultured bovine aortic endothelial cells (BAEC) as a possible explanation for the pH dependent drop in pulmonary vascular resistance. Methods: BAEC were exposed to a pH gradient of 7.1,7.6 for 4 h (short-term) and 16 h (long-term). Standard Western blotting technique was used to detect expression of eNOS. Activity was measured by an indirect assay using bovine aortic smooth muscle cells (BASM) as reporter cells and measuring cGMP levels as a marker of NO production. The cells were exposed to the pH gradient for a total of 4 h and measurement were made at 30, 60 and 90 min, and 2, 3 and 4 hours. Results: eNOS activity and expression remained unchanged during the four and sixteen hours of exposure. Conclusion: In this in vitro experiment, we could not demonstrate an alkalosis-induced increase in eNOS activity and expression. The clinically observed pH dependent vasodilatation does not appear to be directly mediated through the induction of eNOS. [source] | |||||||||||||