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BI 2536 is a new anti-mitotic drug that targets polo-like kinase 1 (Plk1) and is currently under clinical development for cancer therapy. The effect of this drug on cancer cells has been extensively investigated, but information about the effects on primary dividing cells and differentiated non-dividing cells is scarce. We have investigated the effects of this drug on primary neonatal rat cardiac fibroblasts and on differentiated cardiomyocytes and explored the possibility to use this drug to enrich differentiated cell populations in vitro. BI 2536 had a profound effect on cardiac fibroblast proliferation in vitro and arrested these cells in mitosis with an IC50 of about 43 nM. Similar results were observed with primary human cells (HUVEC, IC50  = 30 nM), whereas the cancer cell line HeLa was more sensitive (IC50 of 9 nM). Further analysis revealed that prolonged mitotic arrest resulted in cell death for about 40% of cardiac fibroblasts. The remaining cells showed an interphase morphology with mostly multi- and micro-nucleated nuclei. This indicates that a significant number of primary fibroblasts are able to escape BI 2536 induced mitotic arrest and apparently become aneuploid. No effects were observed on cardiomyocytes and hypertrophic response (growth) upon endothelin-1 and phenylephrine stimulation was normal in the presence of BI 2536. This indicates that BI 2536 has no adverse effects on terminally differentiated cells and still allows proliferation independent growth induction in these cells. In conclusion, cardiomyocytes could be enriched using BI 2536, but the formation of aneuploidy in proliferating cells most likely limits this in vitro application and does not allow its use in putative cell based therapies.

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Interaction mechanism of an antidiabetic agent, 1-deoxynojirimycin (DNJ) with its target protein α-glucosidase (maltase), was investigated by kinetics, fluorescence spectroscopy, UV-vis spectroscopy, circular dichroism, dynamic light scattering coupled with molecular docking analysis. It was found that DNJ reversibly inhibited activity of maltase through a mixed-type manner with IC of (1.5±0.1) μM and inhibition constant K of (2.01±0.02) μM. Fluorescence data and UV-vis information confirmed that the intrinsic fluorescence of maltase was quenched by DNJ through a dynamic quenching procedure due to the collision of them. The calculated thermodynamic parameters including enthalpy change, entropy change and Gibbs free energy change indicated that their binding was spontaneous and the driven force was hydrophobic interaction. Besides, circular dichroism analysis displayed that their binding resulted conformational changes of maltase, characterizing by a decrease of α-helix and an increase in β-sheet. Dynamic light scattering measurements demonstrated the reduction in the hydrodynamic radii of maltase. Further molecular docking revealed that DNJ formed hydrogen bonds with catalytic residues Asp68, Arg212, Asp214, Glu276, Asp349 and Arg439 of maltase, then inhibited the enzyme activity by occupying catalytic center. This study provided a comprehensively understanding about the action mechanism of DNJ on maltase.

Type 1 diabetes (T1D) is an autoimmune disease characterized by the immune cell-mediated progressive destruction of pancreatic β-cells. High-mobility group box 1 protein (HMGB1) has been recognized as a potential immune mediator to enhance the development of T1D. So we speculated that HMGB1 inhibitors could have anti-diabetic effect. Sodium butyrate is a short fatty acid derivative possessing anti-inflammatory activity by inhibiting HMGB1. In the current study, we evaluated the effects of sodium butyrate in streptozotocin (STZ)-induced T1D mice model. Diabetes was induced by multiple low-dose injections of STZ (40 mg/kg/day for 5 consecutive days), and then sodium butyrate (500 mg/kg/day) was administered by intraperitoneal injection for 7 consecutive days after STZ treatment. Blood glucose, incidence of diabetes, body weight, pancreatic histopathology, the amounts of CD4+T cell subsets, IL-1β level in serum and pancreatic expressions levels of HMGB1, and NF-κB p65 protein were analyzed. The results showed that sodium butyrate treatment decreased blood glucose and serum IL-1β, improved the islet morphology and decreased inflammatory cell infiltration, restored the unbalanced Th1/Th2 ratio, and down-regulated Th17 to normal level. In addition, sodium butyrate treatment can inhibit the pancreatic HMGB1 and NF-κB p65 protein expression. Therefore, we proposed that sodium butyrate should ameliorate STZ-induced T1D by down-regulating NF-κB mediated inflammatory signal pathway through inhibiting HMGB1.

Aims  The roles of radiofrequency catheter ablation (RFCA) and pharmacotherapy in treating persistent and long-standing persistent atrial fibrillation (AF) have not been sufficiently investigated. We conducted a multicentre, randomized, controlled trial to compare the effects of RFCA and pharmacotherapy on the prognosis of these patients. Methods and results  A total of 648 patients with persistent and long-standing persistent AF were enrolled from 30 centres and randomized to either the ablation group (n = 327) or the pharmacotherapy group (n = 321). After 54.2 ± 10.6 months of follow-up, the primary endpoints occurred significantly more rarely in the ablation group than in the pharmacotherapy group (10.4% vs. 17.4%; hazard ratio 0.59, 95% confidence interval 0.48–0.75; P < 0.001). The incidence of stroke/transient ischaemic attack (TIA) was significantly lower in the ablation group (4.2% vs. 7.2%, P < 0.001). Likewise, the incidence of new-onset congestive heart failure (CHF) was lower in the ablation group (2.8% vs. 7.2%, P < 0.001). More patients had sinus rhythm in the ablation group than in the pharmacotherapy group (60.6% vs. 20.9%, P < 0.001), but fewer patients were on antiarrhythmic drugs (24.4% vs. 41.6%, P < 0.001) and warfarin (60.8% vs. 83.9%, P = 0.001). Both the 6-min walk distance and the quality of life (QoL) were improved in the ablation group at the end of follow-up. Conclusion  In patients with persistent and long-standing persistent AF, RFCA-based treatment was superior to pharmacotherapy in decreasing stroke/TIA and new-onset CHF and improving QoL.

Fibrinolytic enzymes are the most effective agents for the treatment of thrombotic diseases. In the present study, we purified and characterized an extracellular fibrinolytic serine metalloprotease (named Velefibrinase) that is produced by marine Bacillus velezensis Z01 and assessed its thrombolysis in vivo. SDS-PAGE and MALDI-TOF-MS analyses showed that the molecular mass of Velefibrinase was 32.3 KDa and belonged to the peptidase S8 family. The optimal fibrinolytic activity conditions of Velefibrinase were 40 °C and pH 7.0. Moreover, Velefibrinase exhibited high substrate specificity to fibrin, and a higher ratio of fibrinolytic/caseinolytic (1.48) values, which indicated that Velefibrinase had excellent fibrinolytic properties. Based on the degradation pattern of fibrin and fibrinogen, Velefibrinase could be classified as α/β-fibrinogenase. In vitro, Velefibrinase demonstrated efficient thrombolytic ability, anti-platelet aggregation, and amelioration of blood coagulation (APTT, PT, TT, and FIB), which were superior to those of commercial anticoagulant urokinase. Velefibrinase showed no hemolysis for erythrocyte in vitro and no hemorrhagic activity in vivo. Finally, Velefibrinase effectively prevented mouse tail thrombosis in a dose-dependent (0.22–0.88 mg/kg) manner. These findings suggested that Velefibrinase has the potential to becoming a new thrombolytic agent.

To deal extensively with issues on implicit performance function and huge computational cost in reliability analysis, a new method for structural reliability analysis was proposed by combining the GP and importance sampling method (ISM). Firstly, a small amount of training dataset is generated by the structural analysis to train the GP. Then, the implicit performance and its derivatives are approximated by the trained GP using explicit formulations. Secondly, an iterative algorithm called as the GP-based first-order reliability method is implemented to obtain the design point. During iterations, the precision of the GP approximation in the important region, which contributes significantly to the failure probability, is improved continuously by adding the new iterative design point into the training set. Finally, an importance sampling around the design point is applied to obtain the failure probability. To assess the validity of the proposed method, five numerical examples were presented and discussed, which validated that accurate and computationally efficient results for structural reliability analysis can be obtained using the proposed method.