cyclic-gmp and Carotid-Artery-Diseases

AKT kinase is vital for regulating signal transduction in platelet aggregation. We previously found that mitochondrial protein FUNDC2 mediates phosphoinositide 3-kinase (PI3K)/phosphatidylinositol-3,4,5-trisphosphate (PIP3)-dependent AKT phosphorylation and regulates platelet apoptosis. The aim of this study was to evaluate the role of FUNDC2 in platelet activation and aggregation.. We demonstrated that FUNDC2 deficiency diminished platelet aggregation in response to a variety of agonists, including adenosine 5'-diphosphate (ADP), collagen, ristocetin/VWF, and thrombin. Consistently, in vivo assays of tail bleeding and thrombus formation showed that FUNDC2-knockout mice displayed deficiency in haemostasis and thrombosis. Mechanistically, FUNDC2 deficiency impairs the phosphorylation of AKT and downstream GSK-3β in a PI3K-dependent manner. Moreover, cGMP also plays an important role in FUNDC2/AKT-mediated platelet activation. This FUNDC2/AKT/GSK-3β/cGMP axis also regulates clot retraction of platelet-rich plasma.. FUNDC2 positively regulates platelet functions via AKT/GSK-3β/cGMP signalling pathways, which provides new insight for platelet-related diseases.

Topics: Animals; Autophagy-Related Proteins; Blood Platelets; Carotid Artery Diseases; Clot Retraction; Cyclic GMP; Disease Models, Animal; Glycogen Synthase Kinase 3 beta; Hemostasis; Male; Mice, Knockout; Mitochondrial Proteins; Phosphatidylinositol 3-Kinase; Phosphorylation; Platelet Aggregation; Proto-Oncogene Proteins c-akt; Signal Transduction; Thrombosis

Coagulation factor V (FV) plays a key role in hemostasis, is present in plasma and platelets, and has both pro- and anticoagulant properties; however, the contribution of platelet-derived FV to arterial thrombosis remains undetermined.. Using transgenic mice with various levels of FV gene expression that was restricted to the plasma or platelets, the roles of platelet FV were evaluated in the regulation of arterial thrombosis and platelet activation. Mice with higher levels of platelet FV exhibited faster thrombotic occlusion of the carotid artery after injury compared with mice with lower platelet FV levels. Infusion of platelets with higher levels of FV into transgenic mice with undetectable levels of platelet FV reduced the time to carotid artery occlusion. In contrast, infusion of purified recombinant plasma FV into mice with undetectable platelet FV levels failed to reduce the carotid occlusion times following injury. Evaluation of isolated platelets revealed that platelet-derived FV was critical for the regulation of platelet activation. These effects were associated with an increased level of expression of P-selectin and increased cGMP in platelets.. We established that platelet-derived FV is a critical mediator of arterial thrombosis that involves platelet activation.

Topics: Animals; Blood Coagulation; Blood Platelets; Carotid Artery Diseases; Cyclic GMP; Disease Models, Animal; Factor V; Genetic Predisposition to Disease; Infusions, Intravenous; Male; Mice, Knockout; Phenotype; Platelet Activation; Recombinant Proteins; Selenoprotein P; Thrombosis; Time Factors; Transforming Growth Factor beta

Reduced nitric oxide (NO)/cGMP signalling is observed in age-related vascular disease. We hypothesize that this disturbed signalling involves effects of genomic instability, a primary causal factor in aging, on vascular smooth muscle cells (VSMCs) and that the underlying mechanism plays a role in human age-related vascular disease. To test our hypothesis, we combined experiments in mice with genomic instability resulting from the defective nucleotide excision repair gene ERCC1 (Ercc1(d/-) mice), human VSMC cultures and population genome-wide association studies (GWAS). Aortic rings of Ercc1(d/-) mice showed 43% reduced responses to the soluble guanylate cyclase (sGC) stimulator sodium nitroprusside (SNP). Inhibition of phosphodiesterase (PDE) 1 and 5 normalized SNP-relaxing effects in Ercc1(d/-) to wild-type (WT) levels. PDE1C levels were increased in lung and aorta. cGMP hydrolysis by PDE in lungs was higher in Ercc1(d/-) mice. No differences in activity or levels of cGMP-dependent protein kinase 1 or sGC were observed in Ercc1(d/-) mice compared with WT. Senescent human VSMC showed elevated PDE1A and PDE1C and PDE5 mRNA levels (11.6-, 9- and 2.3-fold respectively), which associated with markers of cellular senescence. Conversely, PDE1 inhibition lowered expression of these markers. Human genetic studies revealed significant associations of PDE1A single nucleotide polymorphisms with diastolic blood pressure (DBP; β=0.28, P=2.47×10(-5)) and carotid intima-media thickness (cIMT; β=-0.0061, P=2.89×10(-5)). In summary, these results show that genomic instability and cellular senescence in VSMCs increase PDE1 expression. This might play a role in aging-related loss of vasodilator function, VSMC senescence, increased blood pressure and vascular hypertrophy.

Topics: Aging; Animals; Blood Pressure; Carotid Arteries; Carotid Artery Diseases; Carotid Intima-Media Thickness; Cells, Cultured; Cellular Senescence; Cyclic GMP; Cyclic Nucleotide Phosphodiesterases, Type 1; Cyclic Nucleotide Phosphodiesterases, Type 5; DNA-Binding Proteins; Dose-Response Relationship, Drug; Endonucleases; Gene Expression Regulation, Neoplastic; Genetic Predisposition to Disease; Genome-Wide Association Study; Humans; Hydrolysis; Hyperplasia; Hypertension; In Vitro Techniques; Mice, Inbred C57BL; Mice, Knockout; Muscle, Smooth, Vascular; Myocytes, Smooth Muscle; Phenotype; Phosphodiesterase 5 Inhibitors; Polymorphism, Single Nucleotide; Second Messenger Systems; Vasodilation; Vasodilator Agents

We have previously identified heavy snoring as an independent risk factor for carotid atherosclerosis. In order to explore the hypothesis that snoring-associated vibration of the carotid artery induces endothelial dysfunction (an established atherogenic precursor), we utilized an animal model to examine direct effects of peri-carotid tissue vibration on carotid artery endothelial function and structure.. In supine anesthetized, ventilated rabbits, the right carotid artery (RCA) was directly exposed to vibrations for 6 h (peak frequency 60 Hz, energy matched to that of induced snoring in rabbits). Similarly instrumented unvibrated rabbits served as controls. Features of OSA such as hypoxemia, large intra-pleural swings and blood pressure volatility were prevented. Carotid endothelial function was then examined: (1) biochemically by measurement of tissue cyclic guanosine monophosphate (cGMP) to acetylcholine (ACh) and sodium nitroprusside (SNP); and (2) functionally by monitoring vessel relaxation with acetylcholine in a myobath.. Vessel cGMP after stimulation with ACh was reduced in vibrated RCA compared with unvibrated (control) arteries in a vibration energy dose-dependent manner. Vibrated RCA also showed decreased vasorelaxation to ACh compared with control arteries. Notably, after addition of SNP (nitric oxide donor), cGMP levels did not differ between vibrated and control arteries, thereby isolating vibration-induced dysfunction to the endothelium alone. This dysfunction occurred in the presence of a morphologically intact endothelium without increased apoptosis.. Carotid arteries subjected to 6 h of continuous peri-carotid tissue vibration displayed endothelial dysfunction, suggesting a direct plausible mechanism linking heavy snoring to the development of carotid atherosclerosis.

Topics: Animals; Carotid Artery Diseases; Cell Survival; Cyclic GMP; Disease Models, Animal; Endothelium, Vascular; Male; Rabbits; Snoring; Vibration

To determine if niacin can confer cardiovascular benefit by inhibiting vascular inflammation and improving endothelial function independent of changes in plasma lipid and lipoprotein levels.. New Zealand white rabbits received normal chow or chow supplemented with 0.6% or 1.2% (wt/wt) niacin. This regimen had no effect on plasma cholesterol, triglyceride, or high-density lipoprotein levels. Acute vascular inflammation and endothelial dysfunction were induced in the animals with a periarterial carotid collar. At the 24-hour postcollar implantation, the endothelial expression of vascular cell adhesion molecule-1, intercellular adhesion molecule-1, and monocyte chemotactic protein-1 was markedly decreased in the niacin-supplemented animals compared with controls. Niacin also inhibited intima-media neutrophil recruitment and myeloperoxidase accumulation, enhanced endothelial-dependent vasorelaxation and cyclic guanosine monophosphate production, increased vascular reduced glutathione content, and protected against hypochlorous acid-induced endothelial dysfunction and tumor necrosis factor alpha-induced vascular inflammation.. Previous human intervention studies have demonstrated that niacin inhibits coronary artery disease. This benefit is thought to be because of its ability to reduce low-density lipoprotein and plasma triglyceride levels and increase high-density lipoprotein levels. The present study showed that niacin inhibits vascular inflammation and protects against endothelial dysfunction independent of these changes in plasma lipid levels.

Topics: Animals; Anti-Inflammatory Agents; Aortic Diseases; Carotid Artery Diseases; Chemokine CCL2; Cyclic GMP; Disease Models, Animal; Dose-Response Relationship, Drug; Endothelium, Vascular; Free Radical Scavengers; Glutathione; Inflammation; Intercellular Adhesion Molecule-1; Lipids; Neutrophil Infiltration; Niacin; Oxidation-Reduction; Peroxidase; Rabbits; Reactive Oxygen Species; Tumor Necrosis Factor-alpha; Vascular Cell Adhesion Molecule-1; Vasodilation; Vasodilator Agents