Features of the Population of Mouse Peritoneal Macrophages Isolated after Stimulation with Concanavalin A and Thioglycolate.

Murine peritoneal macrophages isolated from the lavage fluid after administration of thioglycolate and concanavalin A are presented by two populations of cells of different diameters. Polarization of macrophages into a proinflammatory (M1) phenotype is accompanied by an increase in number of small cells. Macrophages obtained after administration of thioglycolate demonstrate higher tendency to anti-inflammatory (M2) phenotype, while macrophages isolated after administration of concanavalin A are committed in the proinflammatory direction. Lactate level is increased in M1 macrophages in comparison with M2 cells, which indicates predominance of glycolytic metabolism. Macrophages obtained after administration of concanavalin A have reduced mitochondrial potential, which reflects a tendency to apoptosis. Autophagy activation and inhibition neutralize the differences in pro- and anti-inflammatory properties of polarized macrophages obtained after thioglycolate administration, but have less pronounced effect on macrophages obtained after administration concanavalin A. Autophagy inhibitor increases mitochondrial potential in non-polarized macrophages obtained after administration of concanavalin A. These results demonstrate divergent properties of macrophages obtained after administration of glycolate and concanavalin A due to the difference in the mechanisms of experimental peritonitis.

Latent Inflammation and Defect in Adipocyte Renewal as a Mechanism of Obesity-Associated Insulin Resistance.

Obesity is a major risk factor for type 2 diabetes and metabolic syndrome and an essential medical and social problem. In the first part of the review, we briefly highlight the biochemical basis of metabolic disbalance in obesity and evolution of our views on the mechanisms of insulin resistance development in insulin-sensitive tissues. Because obesity relates to the disturbance in the normal physiology of fat tissue, the second part of the review focuses on latent inflammation that develops in obesity and is supported by immune cells. Finally, the problem of adipocyte hypertrophy, reduced regenerative potential of fat progenitor cells, and impaired renewal of fat depots is discussed in the context of type 2 diabetes pathogenesis.

The Role of Urokinase, Tumor Necrosis Factor, and Matrix Metalloproteinase-9 in Monocyte Activation.

TNFα mediates the expression of MMP-9 in THP-1 monocytes induced by urokinase (uPA). Upregulation of MMP-9 caused by uPA and TNFα is suppressed by etanercept, a TNFα inhibitor. In addition, uPA stimulates TNFα mRNA expression. Both uPA and TNFα induce ROS generation in monocytes, while MMP-9 secretion induced by uPA and TNFα is inhibited by antioxidants. Inhibitors of NFκB, ligands of PPARα and PPARγ receptors, and SIRT1 activators negatively affect MMP-9 secretion induced by uPA. MMP-9 secretion during monocyte differentiation into macrophages is downregulated by etanercept and antioxidants. These factors as well as MMP inhibitor GM6001 reduce the number of macrophages attached to substrate during cell differentiation, indicating the role of urokinase, TNFα, and ROS in MMP expression in monocytes and MMP involvement in macrophage maturation.

Gene therapy of type 2 diabetes mellitus: state of art.

Type 2 diabetes mellitus (T2DM) and other metabolic diseases are essential links in the structure of morbidity and mortality in the modern world. The accepted strategy for the correction of T2DM and insulin resistance is drug therapy aimed at delivering insulin from the outside, stimulating the secretion of own insulin and reducing the concentration of blood glucose. However, modern studies demonstrate a great potential for the use of gene therapy approaches for the correction of T2DM and insulin resistance. In the present review, the main variants of plasmid gene therapy of T2DM using the genes of adiponectin and type 1 glucagon-like peptide, as well as the main variants of viral gene therapy of T2DM using the genes of type 1 and leptin are considered. T2DM gene therapy is currently not ready to enter into routine clinical practice, but, subject to improvements in delivery systems, it can be a powerful link in combination therapy for diabetes.

Interleukin-4 Restores Insulin Sensitivity in Lipid-Induced Insulin-Resistant Adipocytes.

Obesity and latent inflammation in adipose tissue significantly contribute to the development of insulin resistance (IR) and type 2 diabetes. Here we studied whether the antiinflammatory interleukin-4 (IL-4) can restore insulin sensitivity in cultured 3T3-L1 adipocytes. The activity of key components of the insulin signaling cascade was assessed by immunoblotting using phospho-specific antibodies to insulin receptor substrate IRS1 (Tyr612), Akt (Thr308 and Ser473), and AS160 (Ser318) protein that regulates translocation of the GLUT4 glucose transporter to the plasma membrane. IR was induced in mature adipocytes with albumin-conjugated palmitate. IR significantly reduced phosphorylation levels of all the above-mentioned proteins. Addition of IL-4 to the culturing medium during IR induction led to a dose-dependent stimulation of the insulin-promoted phosphorylation of IRS1, Akt, and AS160. At the optimal concentration of 50 ng/ml, IL-4 fully restored activation of the insulin cascade in IR cells, but it did not affect insulin signaling activation in the control cells. IL-4 neither upregulated expression of key adipogenesis markers GLUT4 and PPARγ nor caused lipid accumulation in the adipocytes. These results demonstrate that IL-4 can restore insulin sensitivity in adipocytes via mechanisms not associated with induced adipogenesis or de novo formation of lipid depots.