Extracellular human thioredoxin-1 inhibits lipopolysaccharide-induced interleukin-1beta expression in human monocyte-derived macrophages

Oxidative stress plays an important role in atherosclerotic vascular disease, and several recent studies were focused on thioredoxin-1 (Trx-1) and its potential protective role against oxidative stress. Since human monocyte-derived macrophages (HMDM) are important cells in several inflammatory diseases including atherosclerosis, we conducted this study to evaluate the impact of extracellular recombinant human Trx-1 (rhTrx-1) on gene expression in lipopolysaccharide-activated HMDM. Our results showed that rhTrx-1 was capable of reducing interleukin (IL)-1beta mRNA and protein synthesis in a dose-dependent manner. This effect was partly mediated through a reduction of NF-kappaB activation as analyzed by transient transfection and gel shift assays. In addition, we showed that the attenuation of NF-kappaB activity was the result of the reduction of both p50 and p65 subunit mRNA and protein synthesis on one hand and of the induction of I-kappaBalpha mRNA and protein expression on the other hand. Moreover, inhibition of endogenous Trx-1 mRNA was also observed, suggesting a contribution to the diminution of NF-kappaB activity since endogenous Trx-1, in contrast to the exogenous Trx-1, activates the NF-kappaB system. Finally, H2O2-oxidized rhTrx-1 reduced IL-1beta mRNA synthesis in lipopolysaccharide-activated HMDM. This result highly suggested that the rhTrx-1 used in this study could be oxidized in the culture medium and, in turn, reduced IL-1beta mRNA and protein synthesis. Taken together, these data indicated a potential new mechanism through which extracellular rhTrx-1 exerts an anti-inflammatory function in HMDM.     

Brood sex ratio determination by flow cytometry in ants

Sex ratio variations during brood development have important implications for the study of sex allocation in haplodiploid insects. So far, few studies have addressed this question because of the difficulty to determine the sex of the brood. We used flow cytometry to differentiate haploid males from diploid females in the ant Linepithema humile. Our data show that flow cytometry can be used successfully to distinguish between male and female brood on the basis of their DNA content, from the very first larval stage. Moreover, we show that flow cytometry allows sex brood determination in other ant species, as well as in nonsocial Hymenoptera.     

The catalytic activity of the translation termination factor methyltransferase Mtq2-Trm112 complex is required for large ribosomal subunit biogenesis

The Mtq2-Trm112 methyltransferase modifies the eukaryotic translation termination factor eRF1 on the glutamine side chain of a universally conserved GGQ motif that is essential for release of newly synthesized peptides. Although this modification is found in the three domains of life, its exact role in eukaryotes remains unknown. As the deletion of MTQ2 leads to severe growth impairment in yeast, we have investigated its role further and tested its putative involvement in ribosome biogenesis. We found that Mtq2 is associated with nuclear 60S subunit precursors, and we demonstrate that its catalytic activity is required for nucleolar release of pre-60S and for efficient production of mature 5.8S and 25S rRNAs. Thus, we identify Mtq2 as a novel ribosome assembly factor important for large ribosomal subunit formation. We propose that Mtq2-Trm112 might modify eRF1 in the nucleus as part of a quality control mechanism aimed at proof-reading the peptidyl transferase center, where it will subsequently bind during translation termination.     

Environmental levels of oestrogenic and antiandrogenic compounds feminize digit ratios in male rats and their unexposed male progeny

Digit length ratios, especially the second-to-fourth digit ratio (2D : 4D), are associated with various pathological and behavioural conditions in many species including humans and are dependent upon prenatal androgen to oestrogen balance. It is unknown whether digit ratios are modified by environmental exposure to ubiquitous endocrine disruptors. We studied the effect on adult male Wistar rat digit ratios of a gestational exposure to the oestrogenic and antiandrogenic compounds bisphenol A (BPA), genistein and vinclozolin, in low doses, and in combination with investigating in parallel a possible sexual dimorphism of this trait. We also investigated the effects on the male progeny not exposed during gestation. X-rays were taken of the left and right forepaws, and 2D–5D proximal to distal phalanx distances were measured by a standardized procedure based on semi-automatic image analysis. We provide evidence that there is a sexual dimorphism of digit ratios in the Wistar rat, and we found that BPA alone or in combination with genistein and vinclozolin significantly feminized digit ratios in male rats. Intriguingly, significant feminization of digit ratios was also found in the unexposed male progeny of males that had been exposed to compound mixtures. In conclusion, prenatal environmental levels of endocrine-active substances permanently disrupt digit ratios. Digit ratio measurement in adults is thus a promising biomarker of prenatal exposure to low-dose endocrine disruptors in rodents, with potential implications for future studies in humans.     

Effects of exercise training combined with insulin treatment on cardiac NOS1 signaling pathways in type 1 diabetic rats

This study examined the effects of a dual treatment combining insulin treatment and exercise training on basal cardiac function and signaling pathways involving β3-AR, NOS1, and RyR2 in type 1 diabetic rats. Male Wistar rats were assigned into a diabetic group receiving no treatment (D), an insulin-treated diabetic (Ins), a trained diabetic (TD), and a trained insulin-treated diabetic (TIns) group. Control group (C) was included in order to confirm the deleterious effects of diabetes. Insulin treatment and/or treadmill exercise training were conducted for 8 weeks. Basal cardiac function was evaluated by Langendorff technique. Cardiac protein expression of β3-AR, NOS1, and RyR2 was assessed using Western blots. Diabetes induced a decrease of both basal diastolic and systolic (±dP/dt) cardiac function (P < 0.05). Moreover, diabetes was associated with an increase of β3-AR and NOS1 and a decrease of RyR2 expression (P < 0.05). Although combined treatment was not able to normalize -dP/dt, it succeeded to normalize +dP/dt of diabetic rats. Combined treatment led to an overexpression of RyR2. Effects of this combined treatment on +dP/dt and RyR2 were greater than the effects of insulin and exercise training, applied solely. Treatments, applied solely or in combination, resulted in a complete normalization of β3-AR and in a down-regulation of NOS1 because this protein expression in all treated diabetic rats became lower than control values (P < 0.01). Our study shows that unlike single treatments, dual treatment combining insulin treatment and exercise training was able to normalize basal systolic function of diabetic rats by a specific regulation of β3-AR-NOS1-RyR2 signaling pathways.