guanosine-diphosphate and Inflammation

Lipopolysaccharide (LPS) is widely recognized as a potent activator of monocytes/macrophages, and its effects include an altered production of key mediators, such as inflammatory cytokines and chemokines. The involvement of G. We report here that GOT-loaded liposomes inhibited activation of MAPK and blocked the production of the cytokines IL1β, TNFα, IL6, and MCP1 induced by LPS in monocytes and macrophages. Moreover, GOT encapsulated in liposomes reduced monocyte adhesion and chemotaxis. All demonstrated events were in contrast with free GOT, which showed reduced or no effect on monocyte/macrophage activation with LPS.. This study demonstrates the potential of liposomal GOT in blocking LPS proinflammatory effects in monocytes/macrophages.

Topics: Cells, Cultured; Chemokines; Cytokines; GTP-Binding Protein alpha Subunits, Gi-Go; Guanosine Diphosphate; Humans; Inflammation; Interleukin-1beta; Lipopolysaccharides; Liposomes; Macrophage Activation; Macrophages; Monocytes; Thionucleotides; Tumor Necrosis Factor-alpha

Hepcidin, master regulator of iron homeostasis, causes anemia under infectious and inflammatory conditions by reducing intestinal absorption of iron with decreased release of iron from macrophages and liver despite adequate iron stores leading to Anemia of Inflammation (AI). Many therapeutic trials have been carried out but none have been effective due to its adverse effects. In present study, we discover that Guanosine 5'-diphosphate (GDP) encapsulated in lipid vesicle (NH+) was found to inhibit NF-ҝB activation by limiting phosphorylation and degradation of IҝBα, thus, attenuating IL-6 secretion from macrophage cells. Moreover, the suppressed IL-6 levels down regulated JAK2/STAT3 pathway with decrease inflammation-mediated Hamp mRNA transcription (HepG2) and increase iron absorption (Caco2) in HepG2/Caco2 co-culture model. Analogous results were obtained in acute and chronic AI mice model thus, correcting haemoglobin level. These results proved NH + GDP as novel therapeutic agent to overcome limitations and suggests it as potential drug to ameliorate AI.

Topics: Anemia; Animals; Caco-2 Cells; Cell Line, Tumor; Disease Models, Animal; Guanosine; Guanosine Diphosphate; Hep G2 Cells; Hepcidins; Humans; Inflammation; Interleukin-6; Iron; Janus Kinase 2; Liposomes; Macrophages; Male; Mice; Mice, Inbred BALB C; NF-kappa B; Phosphates; Signal Transduction; STAT3 Transcription Factor; U937 Cells

Excess catecholamine levels are suggested to be cardiotoxic and to underlie stress-induced heart failure. The cardiotoxic effects of norepinephrine and epinephrine are well recognized. However, although cardiac and circulating dopamine levels are also increased in stress cardiomyopathy patients, knowledge regarding putative toxic effects of excess dopamine levels on cardiomyocytes is scarce. We now studied the effects of elevated dopamine levels in H9c2 cardiomyoblasts. H9c2 cells were cultured and treated with dopamine (200 μM) for 6, 24, and 48 h. Subsequently, the effects on lipid accumulation, cell viability, flippase activity, reactive oxygen species (ROS) production, subcellular NADPH oxidase (NOX) protein expression, and ATP/ADP and GTP/GDP levels were analyzed. Dopamine did not result in cytotoxic effects after 6 h. However, after 24 and 48 h dopamine treatment induced a significant increase in lipid accumulation, nitrotyrosine levels, indicative of ROS production, and cell death. In addition, dopamine significantly reduced flippase activity and ATP/GTP levels, coinciding with phosphatidylserine exposure on the outer plasma membrane. Furthermore, dopamine induced a transient increase in cytoplasmic and (peri)nucleus NOX1 and NOX4 expression after 24 h that subsided after 48 h. Moreover, while dopamine induced a similar transient increase in cytoplasmic NOX2 and p47

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Animals; Caspase 3; Cell Line; Cell Membrane; Cell Survival; Dopamine; Dopamine Agents; Flow Cytometry; Guanosine Diphosphate; Guanosine Triphosphate; Hydrogen-Ion Concentration; Inflammation; Lipid Metabolism; Microscopy, Electron; Microscopy, Fluorescence; Myoblasts, Cardiac; NADH, NADPH Oxidoreductases; NADPH Oxidase 1; NADPH Oxidase 4; NADPH Oxidases; Nuclear Proteins; Oxidative Stress; Peroxidase; Rats; Reactive Oxygen Species; Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; Tyrosine

In inflammatory bowel disease (IBD), large areas of apparently healthy mucosa lie adjacent to ulcerated intestine. Knowledge of the mechanisms that maintain remission in an otherwise inflamed intestine could provide important clues to the pathogenesis of this disease and provide rationale for clinical treatment strategies. We used kinome profiling to generate comprehensive descriptions of signal transduction pathways in inflamed and noninflamed colonic mucosa in a cohort of IBD patients, and compared the results to non-IBD controls. We observed that p21Rac1 guanosine triphosphatase (GTPase) signaling was strongly suppressed in noninflamed colonic mucosa in IBD. This suppression was due to both reduced guanine nucleotide exchange factor activity and increased intrinsic GTPase activity. Pharmacological p21Rac1 inhibition correlated with clinical improvement in IBD, and mechanistically unrelated pharmacological p21Rac1 inhibitors increased innate immune functions such as phagocytosis, bacterial killing, and interleukin-8 production in healthy controls and patients. Thus, suppression of p21Rac activity assists innate immunity in bactericidal activity and may induce remission in IBD.

Topics: Animals; Biopsy; Crohn Disease; Cyclin-Dependent Kinase Inhibitor p21; Down-Regulation; Enzyme Inhibitors; GTPase-Activating Proteins; Guanine Nucleotide Exchange Factors; Guanosine Diphosphate; Guanosine Triphosphate; Humans; Hydrolysis; Immunity, Innate; Inflammation; Intestinal Mucosa; Protein Kinases; rac1 GTP-Binding Protein; Remission Induction; Signal Transduction; Thioguanine

Neutrophils are first responders rapidly mobilized to inflammatory sites by a tightly regulated, nonredundant hierarchy of chemoattractants. These chemoattractants engage neutrophil cell surface receptors triggering heterotrimeric G-protein Gα(i) subunits to exchange GDP for GTP. By limiting the duration that Gα(i) subunits remain GTP bound, RGS proteins modulate chemoattractant receptor signaling. Here, we show that neutrophils with a genomic knock in of a mutation that disables regulator of G-protein signaling (RGS)-Gα(i2) interactions accumulate in the bone marrow and mobilize poorly to inflammatory sites. These defects are attributable to enhanced sensitivity to background signals, prolonged chemoattractant receptor signaling, and inappropriate CXCR2 downregulation. Intravital imaging revealed a failure of the mutant neutrophils to accumulate at and stabilize sites of sterile inflammation. Furthermore, these mice could not control a nonlethal Staphylococcus aureus infection. Neutrophil RGS proteins establish a threshold for Gα(i) activation, helping to coordinate desensitization mechanisms. Their loss renders neutrophils functionally incompetent.

Topics: Animals; Bone Marrow; Chemotaxis; Down-Regulation; Enzyme Activation; Gene Knock-In Techniques; GTP-Binding Protein alpha Subunit, Gi2; Guanosine Diphosphate; Guanosine Triphosphate; Inflammation; Mice; Mice, Transgenic; Mutation; Neutrophils; Receptors, Interleukin-8B; RGS Proteins; Signal Transduction; Staphylococcal Infections; Staphylococcus aureus; Time Factors