Exercise through a cardiac rehabilitation program attenuates oxidative stress in patients submitted to coronary artery bypass grafting*

Background: Cardiovascular disease is the main cause of morbidity and mortality in the world and oxidative stress has been implicated in the pathogenesis. Cardiac rehabilitation in patients with coronary artery disease submitted to coronary artery bypass grafting may prevent cardiovascular events probably through the attenuation of oxidative stress. The aim of this study was to evaluate the benefits of a cardiac rehabilitation program in the control of the systemic oxidative stress.

Methods: The studied population consisted of 40 patients, with chronic stable coronary artery disease submitted to coronary artery bypass grafting, who attended a cardiac rehabilitation program. Biomarkers of oxidative stress were evaluated in the blood of these patients at different moments.

Results: After the onset of cardiac rehabilitation, there was a significant and progressive decrease in thiobarbituric acid reactive substances levels and protein carbonyls, an initial increase and subsequent decrease in superoxide dismutase, catalase and glutathione peroxidase activities. Also, a progressive increase of uric acid, while ferric reducing antioxidant power levels increased only at the end of the cardiac rehabilitation and a tendency to increase of glutathione contents.

Conclusions: The results suggest that regular exercise through a cardiac rehabilitation program can attenuate oxidative stress in chronic coronary artery disease patients submitted to coronary artery bypass grafting.     

Chronic in vivo hypoxia in various organs: hypoxia-inducible factor-1alpha and apoptosis

We studied the in vivo persistence of hypoxia-inducible factor-1alpha (HIF-1alpha), main transducer of hypoxia, the differential response in organs exposed to the same degree of hypoxemia and the relationship with apoptosis. We measured HIF-1alpha (immunohistochemistry peroxidase and Western blot) and apoptosis (TUNEL) in heart, liver, kidney, gastrocnemius, and brain of rats exposed to chronic normobaric hypoxia (10% O2) or normoxia (21% O2) for 2 weeks. Despite same arterial O2 pressure and increased hemoglobin concentration (219 +/- 5 vs. 124 +/- 4 g/L), the organs responded differently. While marked in brain, muscle, and kidney cortex, HIF-1alpha was undetectable in heart and liver. In kidney medulla, HIF-1alpha was high in both normoxia and hypoxia. By contrast, apoptosis was marked in heart, slight in kidney medulla, and undetectable in other organs. We conclude that the HIF-1alpha response to chronic hypoxia can be a sustained phenomenon, but not in all organs, and that apoptosis responds differently from HIF-1alpha.     

Comparison of 2002 AECG and 2016 ACR/EULAR classification criteria and added value of salivary gland ultrasonography in a patient cohort with suspected primary Sjögren’s syndrome

Background

The objective was to evaluate concordance between 2002 American-European Consensus Group (AECG) and 2016 American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) classification criteria for primary Sjögren’s syndrome (pSS) and to assess how salivary gland ultrasonography (SGUS) might improve the classification of patients.

Methods

Patients with suspected pSS underwent a standardised evaluation, including SGUS, at inclusion into the single-centre Brittany DIApSS cohort. Agreement between the two criteria sets was assessed using Cohen’s κ coefficient. Characteristics of discordantly categorised patients were detailed.

Results

We prospectively included 290 patients between 2006 and 2016, among whom 125 (43%) met ACR/EULAR criteria and 114 (39%) also met AECG criteria; thus, 11 (4%) patients fulfilled only ACR/EULAR, no patients AECG only, and 165 (57%) patients neither criteria set. Concordance was excellent (κ?=?0.92). Compared to patients fulfilling both criteria sets, the 11 patients fulfilling only ACR/EULAR criteria had similar age and symptom duration but lower frequencies of xerophthalmia and xerostomia (p?<?0.01 for each) and salivary gland dysfunction (p?<?0.01); most had systemic involvement (91%), including three (27%) with no sicca symptoms; 91% had abnormal salivary gland biopsy and 46% anti-Sjögren's-syndrome-related antigen A (anti-SSA); 64% were diagnosed with pSS by the physician. SGUS was abnormal in 12% of the 165 patients fulfilling no criteria set. Including SGUS among the ACR/EULAR criteria increased sensitivity from 87.4% to 91.1% when physician diagnosis was the reference standard.

Conclusions

Agreement between AECG and ACR/EULAR criteria sets is excellent. ACR/EULAR criteria are slightly more sensitive and classified some patients without sicca symptoms as having pSS. Including SGUS in the ACR/EULAR criteria may further improve their sensitivity.

     

Residue Glu-91 of Chlamydomonas reinhardtii ferredoxin is essential for electron transfer to ferredoxin-thioredoxin reductase

The [2Fe-2S] soluble ferredoxin from Chlamydomonas reinhardtii was mutated by site directed mutagenesis, using PCR and the expression plasmid pET-Fd as a template. The recombinant mutated proteins were purified to homogeneity and tested in the activation of NADP-malate dehydrogenase, a light dependent reaction in which ferredoxin thioredoxin reductase (FTR) and thioredoxin are involved. The mutation of residue Glu-91 (E92 in spinach, E94 in Anabaena) alone, either to Gln (E91Q) or to Lys (E91K), was found to completely abolish the reaction of the enzyme light activation. On the other hand, the mutants (E92Q) or (E92K) were as efficient as the wild type ferredoxin in this reaction whereas the double mutants (E91Q/E92Q) or (E91K/E92K) had no activity. In addition, a triple mutant (D25A/E28Q/E29Q) was also found to be inactive for this redox dependent light activation. All these mutations had much weaker effects on the ferredoxin/ferredoxin NADP reductase interaction as measured by the cytochrome c reduction assay. These results indicate that there is a recognition site for FTR in the C terminus part of ferredoxin, but also that a core of negatively charged residues in the α1 helix of ferredoxin might be important in the general process of light activation.     

TESD: a transposable element dynamics simulation environment

Various mathematical models have been used to explore the dynamics of transposable elements (TEs) within their host genomes. However, numerous factors can influence their dynamics, and we know only little about the dynamics of TEs when they first began to invade populations. In addition, the influence of population structuring has only recently been investigated. Transposable Element Simulator Dynamics, a population genomics simulation environment, has therefore been developed to provide a simple tool for analyzing the dynamics of TEs in a community based on (i) various TE parameters, such as the transposition and excision rates, the recombination rate and the coefficient of selection against TE insertions; and (ii) population parameters, such as population size and migration rates. The simulations can be used to illustrate the dynamic fate of TEs in structured populations, can be extended by using more specific molecular or demographic models, and can be useful for teaching population genetics and genomics. AVAILABILITY: TESD is distributed under GPL from the P?le Bioinformatique Lyonnais (PBIL) web server at http://pbil.univ-lyon1.fr/software/TESD     

Identification of class II ADP‐ribosylation factors as cellular factors required for hepatitis C virus replication

GBF1 is a host factor required for hepatitis C virus (HCV) replication. GBF1 functions as a guanine nucleotide exchange factor for G‐proteins of the Arf family, which regulate membrane dynamics in the early secretory pathway and the metabolism of cytoplasmic lipid droplets. Here we established that the Arf‐guanine nucleotide exchange factor activity of GBF1 is critical for its function in HCV replication, indicating that it promotes viral replication by activating one or more Arf family members. Arf involvement was confirmed with the use of two dominant negative Arf1 mutants. However, siRNA‐mediated depletion of Arf1, Arf3 (class I Arfs), Arf4 or Arf5 (class II Arfs), which potentially interact with GBF1, did not significantly inhibit HCV infection. In contrast, the simultaneous depletion of both Arf4 and Arf5, but not of any other Arf pair, imposed a significant inhibition of HCV infection. Interestingly, the simultaneous depletion of both Arf4 and Arf5 had no impact on the activity of the secretory pathway and induced a compaction of the Golgi and an accumulation of lipid droplets. A similar phenotype of lipid droplet accumulation was also observed when GBF1 was inhibited by brefeldin A. In contrast, the simultaneous depletion of both Arf1 and Arf4 resulted in secretion inhibition and Golgi scattering, two actions reminiscent of GBF1 inhibition. We conclude that GBF1 could regulate different metabolic pathways through the activation of different pairs of Arf proteins.     

Design, synthesis and biological evaluation of bis(hydroxyphenyl) azoles as potent and selective non-steroidal inhibitors of 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) for the treatment of estrogen-dependent diseases

The 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) catalyses the reduction of the weakly active estrone (E1) into the most potent estrogen, 17beta-estradiol (E2). E2 stimulates the growth of hormone-dependent diseases via activation of the estrogen receptors (ERs). 17beta-HSD1 is often over-expressed in breast cancer cells. Thus, it is an attractive target for the treatment of mammary tumours. The combination of a ligand- and a structure-based drug design approach led to the identification of bis(hydroxyphenyl) azoles as potential inhibitors of 17beta-HSD1. Different azoles and hydroxy substitution patterns were investigated. The compounds were evaluated for activity and selectivity with regard to 17beta-HSD2, ERalpha and ERbeta. The most potent compound is 3-[5-(4-hydroxyphenyl)-1,3-oxazol-2-yl]phenol (18, IC(50)=0.31 microM), showing very good selectivity, high cell permeability and medium CaCo-2 permeability.     

APPL proteins link Rab5 to nuclear signal transduction via an endosomal compartment

Signals generated in response to extracellular stimuli at the plasma membrane are transmitted through cytoplasmic transduction cascades to the nucleus. We report the identification of a pathway directly linking the small GTPase Rab5, a key regulator of endocytosis, to signal transduction and mitogenesis. This pathway operates via APPL1 and APPL2, two Rab5 effectors, which reside on a subpopulation of endosomes. In response to extracellular stimuli such as EGF and oxidative stress, APPL1 translocates from the membranes to the nucleus where it interacts with the nucleosome remodeling and histone deacetylase multiprotein complex NuRD/MeCP1, an established regulator of chromatin structure and gene expression. Both APPL1 and APPL2 are essential for cell proliferation and their function requires Rab5 binding. Our findings identify an endosomal compartment bearing Rab5 and APPL proteins as an intermediate in signaling between the plasma membrane and the nucleus.