Differential Effect of Saturated and Unsaturated Free Fatty Acids on the Generation of Monocyte Adhesion and Chemotactic Factors by Adipocytes: Dissociation of Adipocyte Hypertrophy From Inflammation

OBJECTIVE—Obesity is associated with monocyte-macroph-age accumulation in adipose tissue. Previously, we showed that glucose-stimulated production by adipocytes of serum amyloid A (SAA), monocyte chemoattractant protein (MCP)-1, and hyaluro-nan (HA) facilitated monocyte accumulation. The current objec-tive was to determine how the other major nutrient, free fatty acids (FFAs), affects these molecules and monocyte recruitment by adipocytes. RESEARCH DESIGN AND METHODS—Differentiated 3T3-L1, Simpson-Golabi-Behmel syndrome adipocytes, and mouse embryonic fibroblasts were exposed to various FFAs (250 mol/l) in either 5 or 25 mmol/l (high) glucose for evaluation of SAA, MCP-1, and HA regulation in vitro. RESULTS—Saturated fatty acids (SFAs) such as laurate, myris-tate, and palmitate increased cellular triglyceride accumulation, SAA, and MCP-1 expression; generated reactive oxygen species (ROS); and increased nuclear factor (NF) B translocation in both 5 and 25 mmol/l glucose. Conversely, polyunsaturated fatty acids (PUFAs) such as arachidonate, eicosapentaenate, and docosahexaenate (DHA) decreased these events. Gene expres-sion could be dissociated from triglyceride accumulation. Al-though excess glucose increased HA content, SFAs, oleate, and linoleate did not. Antioxidant treatment repressed glucose- and palmitate-stimulated ROS generation and NFB translocation and decreased SAA and MCP-1 expression and monocyte che-motaxis. Silencing toll-like receptor-4 (TLR4) markedly reduced SAA and MCP-1 expression in response to palmitate but not glucose. DHA suppressed NFB translocation stimulated by both excess glucose and palmitate via a peroxisome prolifterator– activated receptor (PPAR) –dependent pathway. CONCLUSIONS—Excess glucose and SFAs regulate chemotac-tic factor expression by a mechanism that involves ROS genera-tion, NFB, and PPAR, and which is repressed by PUFAs. Certain SFAs, but not excess glucose, trigger chemotactic factor expression via a TLR4-dependent pathway. Diabetes 59:386

Optical characterization of colloidal zinc selenide quantum dots prepared through hydrothermal method

Zinc selenide (ZnSe) quantum dots (QDs) have been synthesized through a hydrothermal method using ZnCl2 and Na2SeO3 powder as the precursor in the presence of oleylamine as capping agent. The hydrothermal route was conducted at a moderate temperature (150°C) for 8 h. Optical properties of ZnSe QDs were studied through ultraviolet-visible spectroscopy (UV-Vis) and photoluminescence (PL) while the structural properties of ZnSe QDs were characterized using transmission electron microscope (TEM). The photoluminescence (PL) characterization on ZnSe QDs showed that the QDs emit light in blue range region at around 440 nm with optical band gap energy at 3.68 eV. The TEM results showed that the average particle size is around 8.9 nm. It is a good candidates for optoelectronic devices such as light emitting diodes (LED)

Serum Amyloid A Impairs the Antiinflammatory Properties of HDL

HDL from healthy humans and lean mice inhibits palmitate-induced adipocyte inflammation; however, the effect of the inflammatory state on the functional properties of HDL on adipocytes is unknown. Here, we found that HDL from mice injected with AgNO3 fails to inhibit palmitate-induced inflammation and reduces cholesterol efflux from 3T3-L1 adipocytes. Moreover, HDL isolated from obese mice with moderate inflammation and humans with systemic lupus erythematosus had similar effects. Since serum amyloid A (SAA) concentrations in HDL increase with inflammation, we investigated whether elevated SAA is a causal factor in HDL dysfunction. HDL from AgNO3-injected mice lacking Saa1.1 and Saa2.1 exhibited a partial restoration of antiinflammatory and cholesterol efflux properties in adipocytes. Conversely, incorporation of SAA into HDL preparations reduced antiinflammatory properties but not to the same extent as HDL from AgNO3-injected mice. SAA-enriched HDL colocalized with cell surface–associated extracellular matrix (ECM) of adipocytes, suggesting impaired access to the plasma membrane. Enzymatic digestion of proteoglycans in the ECM restored the ability of SAA-containing HDL to inhibit palmitate-induced inflammation and cholesterol efflux. Collectively, these findings indicate that inflammation results in a loss of the antiinflammatory properties of HDL on adipocytes, which appears to partially result from the SAA component of HDL binding to cell-surface proteoglycans, thereby preventing access of HDL to the plasma membrane

Roles of Reactive Oxygen Species on Insulin Resistance in Adipose Tissue

Obesity resulting from the delivery of an excess amount of energy to adipose tissue from glucose or free fatty acids is associated with insulin resistance and adipose tissue inflammation. Reactive oxygen species (ROS) have been implicated as contributors to both the onset and the progression of insulin resistance. ROS can be generated by overloading the mitochondrial oxidative phosphorylation system, and also by nicotinamide adenine dinucleotide phosphate oxidases (NOX) produced by either adipocytes, which only produce NOX4, or by macrophages, which produce mainly NOX2. The source of the ROS might differ in the early, intermediate and late stages of obesity, switching from NOX4-dependence in the early phases to NOX2-dependence, in the intermediate phase, and transiting to mitochondria-dependence later in the time course of obesity. Thus, depending on the stage of obesity, ROS can be generated by three distinct mechanisms: i.e., NOX4, NOX2, and mitochondria. In this review, we will discuss whether NOX4-, NOX2-, and/or mitochondria-derived ROS is/are causal in the onset of adipocyte insulin resistance as obesity progresses. Moreover, we will review the pathophysiological roles of NOX4, NOX2, and mitochondria-derived ROS on adipose tissue inflammation

The GanB Galpha-protein negatively regulates asexual sporulation and plays a positive role in conidial germination in Aspergillus nidulans.

We isolated the ganB gene encoding the Galpha-protein homolog from Aspergillus nidulans. To investigate the cellular function of GanB, various mutant strains were isolated. Deletion of constitutively inactive ganB mutants showed conidiation and derepressed brlA expression in a submerged culture. Constitutive activation of GanB caused a reduction in hyphal growth and a severe defect in asexual sporulation. We therefore propose that GanB may negatively regulate asexual sporulation through the BrlA pathway. In addition, deletion or constitutive inactivation of GanB reduced germination rate while constitutive activation led to precocious germination. Furthermore, conidia of a constitutively active mutant could germinate even without carbon source. Taken together, these results indicated that GanB plays a positive role during germination, possibly through carbon source sensing, and negatively regulates asexual conidiation in A. nidulans

First report of a Risso's dolphin (Grampus griseus) stranded in Jeju Island, Republic of Korea: Findings from necropsy, histopathology and microbiome analysis

A female Risso's dolphin (Grampus griseus) carcass was found stranded in fresh condition at Jeju Island of the Republic of Korea on February 18, 2018. Body surface lacerations, gross pathology and histology of the lung indicated the cause of death as drowning by fishing gear entanglement. The dolphin was a five-year-old mature female having ovaries with follicles and a corpus albican. This is the lowest recorded age thus far of a Risso's dolphin with active ovaries. The stomach was filled with Japanese flying squid and based on their distribution, it is believed that the dolphin was foraging in the South Sea, which had not been known as their habitat before. Intestinal microbiome analysis revealed that the bacterial community predominantly comprised phylum Proteobacteria (92.8 per cent). To our knowledge, this is the first microbiome analysis and the first official necropsy report of stranding in Jeju Island of the Risso's dolphin.N