Reactive Oxygen Species and p38 Mitogen-activated Protein Kinase Mediate Exercise-induced Skeletal Muscle-derived Interleukin-6 Expression

Interleukin-6 (IL-6) is a pleiotropic cytokine secreted by many different cell types, and skeletal muscle is an important source of IL-6 during exercise. Here, we studied the effects of glucose deprivation in vitro on skeletal muscle-derived IL-6 expression and release in C2C12 myocytes, as well as its regulation by p38 mitogen-activated protein kinase (p38MAPK) and reactive oxygen species (ROS). C2C12 myotubes were cultured in DMEM medium containing 4.5 g · L−1 glucose (glucose control, GC) or DMEM medium containing no glucose (glucose deprivation, GD) for 0, 6, 12, 18 and 24 hours, and then incubated with 10mM NAC (a ROS scavenger) or 10 μM SB203580 (a p38MAPK inhibitor) under either GC or GD conditions for 24 hours. IL-6 expression levels were subsequently analyzed using RT–PCR, and IL-6 protein levels in the medium were measured using ELISA. Glucose deprivation significantly enhanced IL-6 expression at 18 and 24 hours compared to the glucose control, and caused IL-6 protein levels to increase significantly over the entire 24-hour measurement period. The ROS scavenger NAC inhibited the glucose deprivation-induced release of IL-6 protein almost completely, while the p38MAPK inhibitor SB203580 inhibited glucose deprivation-induced IL-6 protein release to a lesser extent. Our study suggests that glucose deprivation in C2C12 myocytes induces IL-6 expression and release, and that this IL-6 release is mainly mediated via ROS signaling. Skeletal muscle-derived IL-6 may thus play an important role in energy metabolism during exercise

PO-289 Lipidomic analysis of blood serum from prepubertal boys with different BMI

Objective Childhood obesity is a worldwide health problem which may causes metabolic diseases such as hyperglycemia, hyperlipidemia, hypertension and hyperuricemia. It is well know that lipid metabolites regulate fatty acid and glucose homeostasis. Lipidomics is the comprehensive analysis of lipid metabolites which include their quantitation and metabolic pathways. The intention of this study is to identify the circulating lipid species which are altered in obese prepubertal boys. Methods A total number of 72 boys aged 10.28 ±0.69 years old were included into this study, and divided into normal(NC), overweight(OW) and obese group(OB). The degree of maturation of all boys were measured by bone age and sex hormones. Then we measured the form indexes, blood lipids, blood glucose level to identify the current state of all boys. Serum indexes were detected by CLIA and ELISA methods. A lipidomic method was established by using a Waters Acquity UPLCI-Class liquid system combined with Waters Xevo G2-SQ-TOF mass spectrometry system. The identification and analysis of lipid metabolites were complished by using MassLynx 4.1, Progenesis QI software and LipidMaps database. Statistical analyzes were performed using SPSS22.0 software. Results (1)The waist-to-hip ratio, bone age and HDL-c levels ware significant lower in OW and OB groups. The TG level was significant higner in OB group. The DHEA and SHBG levels was significant higner in OW and OB groups and the other sex hormones are not . (2) In this study, 153 most significant different lipid metabolites were founded, incluing 3 diacylglycerol, 32 triglyceride, 1 Phosphatidyl cholines, 1 Phosphatidylinositol, 3 Sphingomyelin, 1 Ceramide which significant higher in OW&OB group; 4 diacylglycerol, 17 Phosphatidic acid, 32 Phosphatidyl cholines, 4 Phosphatidylinositol, 13 Phosphatidylserine, 18 Phosphatidyl ethanolamine, 3 Phosphoglycerides, 13 Sphingomyelin and 6 Ceramide which significant lower in OW&OB group. Among all this metabolites, 8 lipids (fold change ≥5) were founded as the significant biomarkers related prepubertal obesity , including 1 Phosphatidyl cholines, 1 phosphatidylserine, 2 sphingomyelin and 4 Triglyceride. What’s more, the level of SM(d16:1/24:0) and TG(15:0/17:1/20:3) which measured by UPLC-QTOF/MS are highly positive correlated with the level of serum SHBG; PC(18:0/0:0) and TG(16:1/18:0/20:3) are highly negtive correlated with serum SHBG. Conclusions Overweight and obese prepubertal boys showed disorder in lipid metabolism and bone growth. The lipidomic results showed lower SHBG level is related with the disorder of lipid metabolism. We suggest that further studies on these metabolites could help us gain a better understanding of the relationship between obesity and growth disorder

Auto-degradable and biocompatible superparamagnetic iron oxide nanoparticles/polypeptides colloidal polyion complexes with high density of magnetic material

International audienceHypothesis: superparamagnetic iron oxide nanoparticles (SPIONs) are extensively used as building block of colloidal nanocomposites for biomedical applications. Strategies employed to embed them in a biodegradable and biocompatible polymer matrix often fail to achieve a high density of loading which would greatly benefit to applications such as imaging and hyperthermia. In this study, poly(acrylic acid) coated SPION (γ-Fe2O3-PAA) are self-assembled with hydrolysable poly(serine ester) by electrostatic complexation, leading to perfectly defined spherical particles with ultra-high density of magnetic material and an ability to auto-degrade into individual SPION and biocompatible byproducts.Experiments: self-assembly and auto-degradation of γ-Fe2O3-PAA/poly(serine ester) and γ-Fe2O3-PAA/poly(serine ester)-b-PEG colloidal particles are studied by light scattering and microscopy. Colloidal stability in bio-fluids, hyperthermia under alternating magnetic field, cellular uptake, cytotoxicity and degradation of γ-Fe2O3-PAA/poly(serine ester)-b-PEG in living cells are investigated.Findings: a remarkably slow electrostatic complexation leads to dense superparamagnetic γ-Fe2O3-PAA/poly(serine ester)-b-PEG polyion complexes (PICs) with controlled sizes (150 – 500 nm) and times of degradation in aqueous solvents (700 – 5000 h). The material shows good sustainability during hyperthermia, is well taken up by MC3T3 cells and non-cytotoxic. TEM images reveal a mechanism of degradation by “peeling” and fragmentation. In cells, PICs are reduced into individual SPIONs within 72 h

Magnetic-field-induced nonlinear transport in HfTe5

The interplay of electron correlations and topological phases gives rise to various exotic phenomena including fractionalization, excitonic instability, and axionic excitation. Recently-discovered transition-metal pentatellurides can reach the ultra-quantum limit in low magnetic fields and serve as good candidates for achieving such a combination. Here, we report evidences of density wave and metal-insulator transition in HfTe5 induced by intense magnetic fields. Using the nonlinear transport technique, we detect a distinct nonlinear conduction behavior in the longitudinal resistivity within the a-c plane, corresponding to the formation of a density wave induced by magnetic fields. In high fields, the onset of the nonlinear conduction in the Hall resistivity indicates an impurity-pinned magnetic freeze-out as the possible origin of the insulating behavior. These frozen electrons can be gradually re-activated into mobile states above a threshold electric field. These experimental evidences call for further investigations into the underlying mechanism for the bulk quantum Hall effect and field-induced phase transtions in pentatellurides.Comment: 13 pages, 4 figure