Smoking impairs muscle protein synthesis and increases the expression of myostatin and MAFbx in muscle

Smoking causes multiple organ dysfunction. The effect of smoking on skeletal muscle protein metabolism is unknown. We hypothesized that the rate of skeletal muscle protein synthesis is depressed in smokers compared with non-smokers. We studied eight smokers (> or =20 cigarettes/day for > or =20 years) and eight non-smokers matched for sex (4 men and 4 women per group), age (65 +/- 3 and 63 +/- 3 yr, respectively; means +/- SEM) and body mass index (25.9 +/- 0.9 and 25.1 +/- 1.2 kg/m(2), respectively). Each subject underwent an intravenous infusion of stable isotope-labeled leucine in conjunction with blood and muscle tissue sampling to measure the mixed muscle protein fractional synthesis rate (FSR) and whole body leucine rate of appearance (Ra) in plasma (an index of whole body proteolysis), the expression of genes involved in the regulation of muscle mass (myostatin, a muscle growth inhibitor, and MAFBx and MuRF-1, which encode E3 ubiquitin ligases in the proteasome proteolytic pathway) and that for the inflammatory cytokine TNF-alpha in muscle, and the concentration of inflammatory markers in plasma (C-reactive protein, TNF-alpha, interleukin-6) which are associated with muscle wasting in other conditions. There were no differences between nonsmokers and smokers in plasma leucine concentration, leucine rate of appearance, and plasma concentrations of inflammatory markers, or TNF-alpha mRNA in muscle, but muscle protein FSR was much less (0.037 +/- 0.005 vs. 0.059 +/- 0.005%/h, respectively, P = 0.004), and myostatin and MAFBx (but not MuRF-1) expression were much greater (by approximately 33 and 45%, respectivley, P < 0.05) in the muscle of smokers than of nonsmokers. We conclude that smoking impairs the muscle protein synthesis process and increases the expression of genes associated with impaired muscle maintenance; smoking therefore likely increases the risk of sarcopenia.     

Saltmarsh archives of vegetation and land use change from Big River Marsh,SW Newfoundland,Canada

Vegetation History and Archaeobotany - Pollen and plant macrofossils are often well-preserved in coastal sediments, providing a palaeoenvironmental record of sea-level and landscape change. In this...     

Defining the Cause of Death in Hospitalised Patients with Acute Kidney Injury

Background

The high mortality rates that follow the onset of acute kidney injury (AKI) are well recognised. However, the mode of death in patients with AKI remains relatively under-studied, particularly in general hospitalised populations who represent the majority of those affected. We sought to describe the primary cause of death in a large group of prospectively identified patients with AKI.

Methods

All patients sustaining AKI at our centre between 1^st October 2010 and 31^st October 2011 were identified by real-time, hospital-wide, electronic AKI reporting based on the Acute Kidney Injury Network (AKIN) diagnostic criteria. Using this system we are able to generate a prospective database of all AKI cases that includes demographic, outcome and hospital coding data. For those patients that died during hospital admission, cause of death was derived from the Medical Certificate of Cause of Death.

Results

During the study period there were 3,930 patients who sustained AKI; 62.0% had AKI stage 1, 20.6% had stage 2 and 17.4% stage 3. In-hospital mortality rate was 21.9% (859 patients). Cause of death could be identified in 93.4% of cases. There were three main disease categories accounting for three quarters of all mortality; sepsis (41.1%), cardiovascular disease (19.2%) and malignancy (12.9%). The major diagnosis leading to sepsis was pneumonia, whilst cardiovascular death was largely a result of heart failure and ischaemic heart disease. AKI was the primary cause of death in only 3% of cases.

Conclusions

Mortality associated with AKI remains high, although cause of death is usually concurrent illness. Specific strategies to improve outcomes may therefore need to target not just the management of AKI but also the most relevant co-existing conditions.     

The second chromophore in Drosophila photolyase/cryptochrome family photoreceptors

The photolyase/cryptochrome family of proteins are FAD-containing flavoproteins which carry out blue-light-dependent functions including DNA repair, plant growth and development, and regulation of the circadian clock. In addition to FAD, many members of the family contain a second chromophore which functions as a photo-antenna, harvesting light and transferring the excitation energy to FAD and thus increasing the efficiency of the system. The second chromophore is methenyltetrahydrofolate (MTHF) in most photolyases characterized to date and FAD, FMN, or 5-deazariboflavin in others. To date, no second chromophore has been identified in cryptochromes. Drosophila contains three members of the cryptochrome/photolyase family: cyclobutane pyrimidine dimer (CPD) photolyase, (6-4) photoproduct photolyase, and cryptochrome. We developed an expression system capable of incorporating all known second chromophores into the cognate cryptochrome/photolyase family members. Using this system, we demonstrate that Drosophila CPD photolyase and (6-4) photolyase employ 5-deazariboflavin as their second chromophore, but Drosophila cryptochrome, which is evolutionarily closer to (6-4) photolyase than the CPD photolyase, lacks a second chromophore.     

Inhaled adenosine A(2A) receptor agonists for the treatment of chronic obstructive pulmonary disease

COPD is a major cause of mortality in the western world. A(2A) agonists are postulated to reduce the lung inflammation that causes COPD. The cardiovascular effects of A(2A) agonists dictate that a compound needs to be delivered by inhalation to be therapeutically useful. A strategy of minimizing side-effect liability by maximizing systemic clearance was followed and pharmacological and pharmacokinetic SAR of a series of inhaled A(2A) agonists described. A sevenfold improvement in potency and 150-fold reduction in side-effect liability over the lead compound CGS-21680, were obtained.     

Integrated multi-level quality control for proteomic profiling studies using mass spectrometry

Background

Evolutionary conservation of RNA secondary structure is a typical feature of many functional non-coding RNAs. Since almost all of the available methods used for prediction and annotation of non-coding RNA genes rely on this evolutionary signature, accurate measures for structural conservation are essential.

Results

We systematically assessed the ability of various measures to detect conserved RNA structures in multiple sequence alignments. We tested three existing and eight novel strategies that are based on metrics of folding energies, metrics of single optimal structure predictions, and metrics of structure ensembles. We find that the folding energy based SCI score used in the RNAz program and a simple base-pair distance metric are by far the most accurate. The use of more complex metrics like for example tree editing does not improve performance. A variant of the SCI performed particularly well on highly conserved alignments and is thus a viable alternative when only little evolutionary information is available. Surprisingly, ensemble based methods that, in principle, could benefit from the additional information contained in sub-optimal structures, perform particularly poorly. As a general trend, we observed that methods that include a consensus structure prediction outperformed equivalent methods that only consider pairwise comparisons.

Conclusion

Structural conservation can be measured accurately with relatively simple and intuitive metrics. They have the potential to form the basis of future RNA gene finders, that face new challenges like finding lineage specific structures or detecting mis-aligned sequences.     

Mining the archival formalin-fixed paraffin-embedded tissue proteome: opportunities and challenges

The significant potential of tissue-based proteomic biomarker studies can be restricted by difficulties in accessing samples in optimal fresh-frozen form. While archival formalin-fixed tissue collections with attached clinical and outcome data represent a valuable alternate resource, the use of formalin as a fixative which induces protein cross-linking, has generally been assumed to render them unsuitable for proteomic studies. However, this view has been challenged recently with the publication of several papers accomplishing variable degrees of heat-induced reversal of cross-links. Although still in its infancy and requiring the quantitative optimisation of several critical parameters, formalin-fixed tissue proteomics holds promise as a powerful tool for biomarker-driven translational research. Here, we critically review the current status of research in the field, highlighting challenges which need to be addressed for robust quantitative application of protocols to ensure confident high impact inferences can be made.     

Synthesis of a novel hepatitis C virus protein by ribosomal frameshift.

Hepatitis C virus (HCV) is an important human pathogen that affects approximately 100 million people worldwide. Its RNA genome codes for a polyprotein, which is cleaved by viral and cellular proteases to produce at least 10 mature viral protein products. We report here the discovery of a novel HCV protein synthesized by ribosomal frameshift. This protein, which we named the F protein, is synthesized from the initiation codon of the polyprotein sequence followed by ribosomal frameshift into the -2/+1 reading frame. This ribosomal frameshift requires only codons 8-14 of the core protein-coding sequence, and the shift junction is located at or near codon 11. An F protein analog synthesized in vitro reacted with the sera of HCV patients but not with the sera of hepatitis B patients, indicating the expression of the F protein during natural HCV infection. This unexpected finding may open new avenues for the development of anti-HCV drugs.