Charting calcium-regulated apoptosis pathways using chemical biology: role of calmodulin kinase II

<p>Abstract</p> <p>Background</p> <p>Intracellular free calcium ([Ca²⁺]_i) is a key element in apoptotic signaling and a number of calcium-dependent apoptosis pathways have been described. We here used a chemical biology strategy to elucidate the relative importance of such different pathways.</p> <p>Results</p> <p>A set of 40 agents ("bioprobes") that induce apoptosis was first identified by screening of a chemical library. Using p53, AP-1, NFAT and NF-κB reporter cell lines, these bioprobes were verified to induce different patterns of signaling. Experiments using the calcium chelator BAPTA-AM showed that Ca²⁺was involved in induction of apoptosis by the majority of the bioprobes and that Ca²⁺was in general required several hours into the apoptosis process. Further studies showed that the calmodulin pathway was an important mediator of the apoptotic response. Inhibition of calmodulin kinase II (CaMKII) resulted in more effective inhibition of apoptosis compared to inhibition of calpain, calcineurin/PP2B or DAP kinase. We used one of the bioprobes, the plant alkaloid helenalin, to study the role of CaMKII in apoptosis. Helenalin induced CaMKII, ASK1 and Jun-N-terminal kinase (JNK) activity, and inhibition of these kinases inhibited apoptosis.</p> <p>Conclusion</p> <p>Our study shows that calcium signaling is generally not an early event during the apoptosis process and suggests that a CaMKII/ASK1 signaling mechanism is important for sustained JNK activation and apoptosis by some types of stimuli.</p

Calprotectin is superior to procalcitonin as a sepsis marker and predictor of 30-day mortality in intensive care patients

Sepsis is the most frequent cause of death in the intensive care unit (ICU). A rapid and correct diagnosis and initiation of therapy is crucial for improving patient outcomes. The aim of this study was to compare the performance of calprotectin with the more widely used sepsis biomarker procalcitonin (PCT) in ICU patients. The performance of calprotectin and PCT as sepsis and prognostic markers for 30-d mortality was compared in a prospective, observational study in an eight-bed ICU. We investigated concentrations of the biomarkers in plasma collected at admission from all ICU patients admitted during a year (2012-2013, n = 271) together with simplified acute physiology 3 scores (SAPS3) and sequential organ failure assessment (SOFA) scores. The receiver operating characteristic (ROC) analysis showed a higher area under the curve (AUC) value for calprotectin (0.79) than for PCT (0.49) when used as a sepsis marker. The calprotectin concentrations at admission were higher in non-survivors than in survivors at day 30. In our study, calprotectin was superior to PCT for distinguishing between ICU patients with sepsis and non-sepsis patients. Calprotectin also had higher predictive ability regarding 30-d mortality

Good Agreement Between Hba1c Analyzed Using Capillary Electrophoresis, HPLC, Immunological and Enzymatic Methods

Purpose: Hemoglobin A1c (HbA1c) is an essential marker for assessment of glycemic control in diabetes patients. The aim of this study was to evaluate the agreement between different HbA1c methods. Methodology: We used blood samples to compare HbA1c results analyzed with Capillarys 3 Tera, Roche Tina-Quant HbA1c Gen 3, BioRad Variant II Turbo (3 sites), Mono S® and Abbott Architect enzymatic method. The comparisons were made as paired instrument comparisons with Capillarys 3 Tera. Results: The linear correlations between the HbA1c methods were as follows: Cobas 6000 = 0.982 x Capillarys 3 Tera + 0.975, R² = 0.994; Architect c8000 = 0.982 x Capillarys 3 Tera + 1.064, R² = 0.994; Mono S® = 0.916 x Capillarys 3 Tera + 3.397, R² = 0.965; BioRad Variant II Turbo = 0.923 x Capillarys 3 Tera + 4.062, R² = 0.990; Tosoh G8 = 0.963 x Capillarys 3 Tera + 3.895, R² = 0.996. Conclusions: The different instrument platforms showed the best agreement in the 50-70 mmol/mol interval. Above and below this range the methods separated into 2 groups, one consisting of Capillarys 3 Tera, Roche Tina-Quant and Abbott enzymatic method and the other group consisting of BioRad Variant II Turbo, Tosoh G8 and Mono S®