Coordination between proteasome impairment and caspase activation leading to TAU pathology: neuroprotection by cAMP

Neurofibrillary tangles (NFTs) are hallmarks of Alzheimer's disease (AD). The main component of NFTs is TAU, a highly soluble microtubule-associated protein. However, when TAU is cleaved at Asp421 by caspases it becomes prone to aggregation leading to NFTs. What triggers caspase activation resulting in TAU cleavage remains unclear. We investigated in rat cortical neurons a potential coordination between proteasome impairment and caspase activation. We demonstrate that upon proteasome inhibition, the early accumulation of detergent-soluble ubiquitinated (SUb) proteins paves the way to caspase activation and TAU pathology. This occurs with two drugs that inhibit the proteasome by different means: the product of inflammation prostaglandin J2 (PGJ2) and epoxomicin. Our results pinpoint a critical early event, that is, the buildup of SUb proteins that contributes to caspase activation, TAU cleavage, TAU/Ub-protein aggregation and neuronal death. Furthermore, to our knowledge, we are the first to demonstrate that elevating cAMP in neurons with dibutyryl-cAMP (db-cAMP) or the lipophilic peptide PACAP27 prevents/diminishes caspase activation, TAU cleavage and neuronal death induced by PGJ2, as long as these PGJ2-induced changes are moderate. db-cAMP also stimulated proteasomes, and mitigated proteasome inhibition induced by PGJ2. We propose that targeting cAMP/PKA to boost proteasome activity in a sustainable manner could offer an effective approach to avoid early accumulation of SUb proteins and later caspase activation, and TAU cleavage, possibly preventing/delaying AD neurodegeneration.

Quantum spin liquid in frustrated one-dimensional LiCuSbO4

A quantum magnet, LiCuSbO4, with chains of edge-sharing spin-1/2 CuO6 octahedra is reported. While short-range order is observed for T<10  K, no zero-field phase transition or spin freezing occurs down to 100 mK. Specific heat indicates a distinct high-field phase near the 12 T saturation field. Neutron scattering shows incommensurate spin correlations with q=(0.47±0.01)π/a and places an upper limit of 70  μeV on any spin gap. Exact diagonalization of 16-spin easy-plane spin-1/2 chains with competing ferro- and antiferromagnetic interactions (J1=-75  K, J2=34  K) accounts for the T>2  K data.

Comprehensive gene expression profiling and immunohistochemical studies support application of immunophenotypic algorithm for molecular subtype classification in diffuse large B-cell lymphoma: a report from the International DLBCL Rituximab-CHOP Consortium Program Study

Gene expression profiling (GEP) has stratified diffuse large B-cell lymphoma (DLBCL) into molecular subgroups that correspond to different stages of lymphocyte development-namely germinal center B-cell like and activated B-cell like. This classification has prognostic significance, but GEP is expensive and not readily applicable into daily practice, which has lead to immunohistochemical algorithms proposed as a surrogate for GEP analysis. We assembled tissue microarrays from 475 de novo DLBCL patients who were treated with rituximab-CHOP chemotherapy. All cases were successfully profiled by GEP on formalin-fixed, paraffin-embedded tissue samples. Sections were stained with antibodies reactive with CD10, GCET1, FOXP1, MUM1 and BCL6 and cases were classified following a rationale of sequential steps of differentiation of B cells. Cutoffs for each marker were obtained using receiver-operating characteristic curves, obviating the need for any arbitrary method. An algorithm based on the expression of CD10, FOXP1 and BCL6 was developed that had a simpler structure than other recently proposed algorithms and 92.6% concordance with GEP. In multivariate analysis, both the International Prognostic Index and our proposed algorithm were significant independent predictors of progression-free and overall survival. In conclusion, this algorithm effectively predicts prognosis of DLBCL patients matching GEP subgroups in the era of rituximab therapy.

Wingspan stents for the treatment of symptomatic atherosclerotic stenosis in small intracranial vessels: safety and efficacy evaluation

BACKGROUND AND PURPOSE

Until now, endovascular treatment of symptomatic atherosclerotic stenosis in small intracranial arteries (≤2.5 mm) was limited. We evaluated the safety and efficacy of the treatment by using Wingspan stents in arteries of this caliber.

MATERIALS AND METHODS

From March 2007 to July 2010, 53 symptomatic intracranial stenoses with narrowing of at least 50% in 53 patients were treated by using Wingspan stents. Clinical manifestations and imaging features were recorded.

RESULTS

The technical success rate was 98.1%. There were no serious complications, with the exception of 1 patient who experienced a small cerebral hemorrhage caused by perforation of microwire. Thirty-nine patients (74%) were available for follow-up imaging with DSA. ISR was documented in 13 of these patients, including 2 patients with symptomatic ISR. The median length of the vascular lesions was 5.39 mm, and patients whose vascular lesions were longer than 5.39 mm had a much higher incidence of ISR than patients whose vascular lesions were shorter than 5.39 mm (53% versus 15%, respectively). The median ratio of the reference artery diameter to the stent diameter was 0.78, and patients whose ratio was smaller than 0.78 had a much higher incidence of ISR than patients whose ratio was larger than 0.78 (53% versus 15%, respectively).

CONCLUSIONS

In our series, percutaneous transluminal angioplasty and stent placement of small intracranial arteries by using Wingspan stents was safe. The ISR rate was relatively high; most patients having ISR were asymptomatic. Further follow-up is needed to assess the long-term efficacy of this procedure.

Reliability test of an electron cyclotron resonance ion source for accelerator driven sub-critical system

The reliability test of an electron cyclotron resonance ion source developed for accelerator driven sub-critical system is carried out in China Institute of Atomic Energy. A unique technique to improve the reliability is adopted. The source is operated for more than 200 h at 75 keV, 100 mA extracted hydrogen current, while 2 beam trips are recorded in the period, and uninterrupted operation time is about 150 h. The experimental result is described.

A cascade of anoxic and oxic fluidized bed biofilm reactors for treatment of synthetic municipal wastewater

In this study, a cascade of anoxic and oxic fluidized bed biofilm reactors system was carried out to treat synthetic municipal wastewater. The parameters of the influent flow rates and C/N ratios were discussed. System performance was acceptable for chemical oxygen demand (COD), ammonia, and total nitrogen removal. A decrease of ammonia and total nitrogen removal efficiencies, however, was observed when the influent flow rates increased to 5.04 and 6.12 1 h(-1). Total nitrogen removal decreased at the influent C/N ratio of 3:1. The measured ratios of COD reduction in the anoxic column to nitrogen removal through nitrification-denitrification were 3.7, 3.5, 3.3, and 3.1 g COD/g(-1) N on average when the influent C/N ratios changed from 6:1 to 3:1. The observed sludge yield (Yobs) was 0.169 g VSS g COD(-1) because of perfect denitrification in the anoxic column and the relatively long solids retention time.

Three-dimensional gadolinium-enhanced MR venography to evaluate central venous steno-occlusive disease in hemodialysis patients

AIM

To determine the agreement and diagnostic accuracy of three-dimensional gadolinium-enhanced magnetic resonance venography (3D-Gd-MRV) in central venous steno-occlusive disease (CVSD) in haemodialysis patients.

MATERIALS AND METHODS

Fourteen consecutive haemodialysis patients underwent interventional procedures to evaluate or treat CVSD. 3D-Gd-MRV was performed before the procedures and the results were compared with digital subtraction angiography (DSA).

RESULTS

DSA showed >50% stenosis in all 14 patients, 13 of whom were diagnosed correctly using 3D-Gd-MRV. Moderate stenosis was missed at 3D-Gd-MRV in one case whereby the indwelling dialysis central venous catheter may have caused an artefact on the images and hindered the accuracy of the result. The sensitivity of 3D-Gd-MRV in revealing stenosis was 93% (13/14). No complications caused by contrast agent toxicity occurred in any patient.

CONCLUSION

3D-Gd-MRV employing a non-breath-hold technique is highly sensitive in the diagnosis of CVSD and may be an alternative technique to DSA for the visualization of central veins.

Association between polymorphisms in IL17F and male asthma in a Chinese population

BACKGROUND AND OBJECTIVES

Interleukin (IL) 17F is a marker of type 17 helper T cells and has a proinflammatory role in asthma.The aim of the present study was to assess the possible association between asthma and polymorphisms in the IL17F gene in a Chinese population.

METHODS

A total of 318 asthmatic patients and 352 nonasthmatic controls were recruited. Two single-nucleotide polymorphisms in IL17F (rs763780 and rs13209590) were detected using GenomeLab SNPstream. Logistic regression methods were used to analyze data.

RESULTS

A significantly lower frequency of the C allele in rs763780 was observed in the control group (P = .0148). The rs763780 TC heterozygote was associated with an increased risk of asthma, and a similar trend was observed assuming a codominant genotype effect (adjusted OR, 1.58; 95% CI, 1.06-2.36; P = .0148; adjusted OR, 1.64; 95% CI, 1.10-2.45; P = .0217). Furthermore, a novel finding of the present study was that this association was exclusive to males (adjusted OR, 1.79; 95% CI, 1.06-3.05; P = .0308) and patients with higher immunoglobulin E levels (> or = 1.85 IU/mL) (adjusted OR, 1.88; 95% CI, 1.10-3.22; P = .0213). We also found that the haplotype with minor alleles for rs763780 was associated with an increased risk of asthma (adjusted OR, 1.62; 95% CI, 1.11-2.35; P = .0115).

CONCLUSION

Our findings indicated that polymorphisms might play a role in susceptibility to asthma.

Apoptotic gene expression by human periodontal ligament cells following cyclic stretch

BACKGROUND AND OBJECTIVE

Periodontal ligament cells play an important role in maintaining homeostasis of periodontal tissue upon mechanical force loading caused by mastication or orthodontic force. Previous studies revealed force-driven periodontal ligament cell death via apoptosis, but the force-sensing genes assigned to the apoptotic pathway have not been fully characterized. The present study aimed to identify force-sensing genes implicated in the apoptotic pathway in periodontal ligament cells.

MATERIAL AND METHODS

Human periodontal ligament cells were exposed to 20% stretch strain for 6 or 24 h, and the differential expression of 84 genes implicated in the apoptotic pathway were quantified by real-time PCR array technology.

RESULTS

Ten and 11 genes showed upregulated expression after 6 and 24 h stretches, respectively, and there were two downregulated genes in response to both 6 and 24 h stretches. These genes included those encoding the tumor necrosis factor ligand family (TNFSF8), tumor necrosis factor receptor family (FAS, TNFRSF10B, TNFRSF11B, TNFRSF25 and CD27), the Bcl-2 family (BAG3, BAK1, BCL2L11 and BCLAF1), the caspase family (CASP5 and CASP7), the inhibitor of apoptosis proteins family (BIRC3, BIRC6 and NAIP), the caspase recruitment domain family (RIPK2 and PYCARD) and the death domain family (DAPK1), as well as an oncogene (BRAF).

CONCLUSION

This study identified several force-sensing genes implicated in the apoptotic pathway in periodontal ligament cells and should facilitate future studies on force-driven apoptosis by providing putative target genes.