Engagement of the inhibitory receptor CD158a interrupts TCR signaling,preventing dynamic membrane reorganization in CTL/tumor cell interaction

Renal cell carcinoma (RCC) infiltrating lymphocytes (TILs) express killer cell immunoglobulinlike receptors (KIRs) that inhibit the antitumor CD8(+) T-cell lysis. In the present study, to better examine the functional consequences of KIR engagement on cytotoxic T lymphocyte (CTL)/tumor interaction, we have investigated the influence of KIR CD158a on early steps of T-cell activation. We show that coengagement of T-cell receptor (TCR) and CD158a by tumor cells inhibited tyrosine phosphorylation of early signaling proteins ZAP-70 and LAT, lipid raft coalescence, and TCR/CD3 accumulation at the CTL/tumor cell interface. In addition, the guanine exchange factor Vav was not phosphorylated, and no actin cytoskeleton rearrangement was observed. Our data indicate a role of KIR CD158a in the dynamic events induced by TCR triggering, preventing CTL membrane reorganization, and subsequent completion of CTL activation program. Accordingly, the expression of CD158 by TILs may favor tumor cell escape to the immune response.     

Toward a biotechnological heparin through combined chemical and enzymatic modification of the Escherichia coli K5 polysaccharide.

A process to generate glycosaminoglycans with heparin- and heparan sulfate-like sequences from the Escherichia coli K5 capsular polysaccharide is described. This polymer has the same structure as N-acetylheparosan, the precursor in heparin/ heparan sulfate biosynthesis. The process involves chemical N-deacetylation and N-sulfation, enzymatic conversion of up to 60% of the D-glucuronic acid to L-iduronic acid residues, and chemical O-sulfation. Because direct sulfation afforded unwanted 3-O-sulfated (instead of 2-O-sulfated) iduronic acid residues, a strategy involving graded solvolytic desulfation of chemically oversulfated C5-epimerized sulfaminoheparosans was assessed using persulfated heparin and heparan sulfate as model compounds. The O-desulfation process was shown to increase the anti-factor Xa activity of oversulfated heparin.     

The use of a telematic connection for the follow-up of hypertensive patients improves the cardiovascular prognosis

BACKGROUND: Inadequate blood pressure (BP) control could be due to incorrect management of hypertensives caused by the lack of interaction between general practitioners (GP) and hypertension specialists. OBJECTIVES: To test the effectiveness on BP and total cardiovascular risk (TCVR) control of an internet-based digital network connecting specialists and GPs. METHODS: We created a network among the Hypertension Clinic, Federico II University (Naples, Italy), 23 hospital-based hypertension clinics and 60 GPs from the area (CampaniaSalute Network, CS). Randomized GPs enrolled in CS could update online records of patients (n = 1979). As a control, we included 2045 patients referred to the specialist clinics by GPs from outside the network. All patients completed a 2-year follow-up. RESULTS: CS provided a larger reduction in BP [systolic/diastolic BP (SBP/DBP): 7.3 +/- 0.4/5.4 +/- 0.3 versus 4.1 +/- 0.4/3.1 +/- 0.26 mmHg, CS versus control; P < 0.001 for both] and percentage of patients with BP < 140/90 mmHg (CS versus control: baseline, 33 versus 34%, NS; end of follow-up, 51 versus 47%, chi = 13.371; P < 0.001). A European Society of Hypertension-European Society of Cardiology (ESH/ESC) TCVR score was calculated [from 1 (average) to 5 (very high TCVR)]. The CS group showed a reduction in the mean TCVR score (CS: from 3.5 +/- 0.02 to 3.2 +/- 0, P < 0.01, ANOVA; control group: 3.5 +/- 0.03 to 3.4 +/- 0.03, NS) and, accordingly, fatal and non-fatal major cardiovascular events (MACE) were less frequent (2.9 versus 4.3%; chi = 5.047, P < 0.02). CS predicts fewer MACE in multiple binary regression analysis (beta:-7.27, P < 0.008) reducing the risk for MACE compared to control [odds ratio (OR): 0.838; 95% confidence interval (CI): 0.73-0.96]. CONCLUSION: Our results support the idea that telemedicine can achieve better control of BP and TCVR.     

A shorter time to the first treatment may be predicted by the absolute number of regulatory T-cells in patients with Rai stage 0 chronic lymphocytic leukemia

Regulatory T-cells (Tregs) are increased in chronic lymphocytic leukemia(CLL) and correlates with clinical and biological features of active/progressive disease. However, little is known about their ability to predict the time to first treatment (TFT). We evaluated 75 patients with Rai stage 0 CLL, in whom the absolute number of Tregs was determined at diagnosis, and correlated to main clinical and biological features, as well as to the need of receiving any specific therapy during the course of the disease. After a median follow-up of 30 months, 12 patients(16%) required therapy at some time from the diagnosis. Treated patients showed a significant higher number of peripheral white blood cells and B-lymphocytes, platelet count, cases with unmutated immunoglobulin heavy chain status, and high-risk cytogenetic abnormalities,as well as lower hemoglobin values, than patients who did not need therapy. A greater number of circulating Tregs was detected in treated patients (P < 0.001). Multivariate analysis confirmed that the absolute number of Tregs was an independent predictor of TFT in these patients, the best predictive cut-off being 41/mL. These data show that the absolute Tregs cell number is able to identify Rai stage 0 CLL patients at higher risk of requiring therapy.     

Preservation of nutritional-status in patients with refractory ascites due to hepatic cirrhosis who are undergoing repeated paracentesis

Background and Aim: Refractory ascites in liver‐cirrhosis is associated with a poor prognosis. We performed a prospective study to investigate whether aggressive nutritional‐support could improve outcomes in cirrhotic patients. Methods: Cirrhotic patients undergoing serial large‐volume paracentesis for refractory‐ascites were enrolled and randomized into three groups. Group A received post‐paracentesis intravenous nutritional‐support in addition to a balanced oral diet and a late‐evening protein snack, group B received the same oral nutritional‐protocol as the first group but without parenteral support, and group C (the control group) received a low‐sodium or sodium‐free diet. Clinical, anthropometric and laboratory nutritional parameters and biochemical tests of liver and renal function were reported for 12 months of follow‐up. Results: We enrolled 120 patients, who were randomized into three groups of equal size. Patients on the nutritional‐protocol showed better preservation of clinical, anthropometric and laboratory nutritional parameters that were associated with decreased deterioration of liver function compared with patients on the low‐sodium or sodium‐free diet (group C). Groups A and B had lower morbidity and mortality rates than the control group (C). Mortality rates were significantly better in patients who were treated with parenteral‐nutritional‐support than for the other two groups. In patients who were on the nutritional‐protocol, there was a reduction in the requirement of taps for the treatment of refractory ascites. Conclusions: Post‐paracentesis parenteral‐nutritional‐support with a balanced oral diet and an evening protein snack appears to be the best care protocol for patients with liver‐cirrhosis that has been complicated by refractory‐ascites.     

Nitric oxide boosts TLR‐4 mediated lipocalin 2 expression in chondrocytes

Lipocalin 2 (LCN2) has recently emerged as a novel adipokine involved in different processes including arthritis and chondrocyte inflammatory response. However, little is known about its activity on chondrocyte homeostasis and its regulation by nitric oxide (NO) Hence, we performed a set of experiments aimed to achieve a better understanding of this relationship. Cell vitality was tested in the ATDC5 cell line by the MTT colorimetric assay. Protein expression and gene expression was evaluated by Western blot and real time RT‐PCR, respectively. NO production (determined as nitrite accumulation) was assayed by the Griess reaction. First, we demonstrated that LCN2 decreased murine chondrocytes vitality. Next, LCN2 co‐stimulation with LPS enhanced NOS2 protein expression by murine chondrocytes. In addition, inhibition of LPS‐induced nitric oxide production by aminoguanidine, a selective NOS2 inhibitor, significantly reduced LPS‐mediated LCN2 expression. In contrast, treatment of murine chondrocytes with sodium nitroprussiate (SNP), a classic NO donor, scarcely induced LCN2 expression. Intriguingly, SNP addition to LPS‐challenged chondrocytes, treated with aminoguanidine, provoked a strong induction of LCN2 expression. Finally, murine ATDC5 cells, co‐cultured with LPS pre‐challenged macrophages, had higher LCN2 expression in comparison with murine chondrocytes co‐cultured with non pre‐challenged macrophages. In this work we have described for the first time that NO is able to exert a control on LCN2 expression, suggesting the existence of a feedback loop regulating its expression. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1046–1052, 2013     

Altered peptide ligands induce quantitatively but not qualitatively different intracellular signals in primary thymocytes

Interaction of the T cell receptor (TCR) with peptide/major histocompatibility complexes (MHC) in the thymus is of critical importance for developing thymocytes. In a previous study, we described an antagonist peptide that inhibited negative selection of transgenic thymocytes induced by an agonist peptide. In this study we show that this antagonist peptide can induce positive selection of CD8⁺ thymocytes more efficiently than the agonist or the weak agonist peptides, whereas the opposite is true for their ability to cause negative selection. The intracellular signals induced in thymocytes by such peptides after TCR ligation was examined in CD4⁺8⁺ double-positive thymocytes from F5/β₂m^o/Rag-1^o transgenic mice. TCR ligation with either the agonist, weak agonist, or antagonist peptide variants resulted in hyperphosphorylation of CD3ζ, CD3, ZAP-70, Syk, Vav, SLP-76, and pp36–38. The extent of phosphorylation of these intracellular proteins correlated with the efficiency with which the peptide analogs induced apoptosis of immature thymocytes. Unexpectedly, there was no correlation between the upstream TCR signaling pathways analyzed and the capacity of the different peptides to induce positive selection.