Expression of Cyclic GMP-AMP Synthase in Patients With Systemic Lupus Erythematosus.

OBJECTIVE: Type I interferon (IFN) is implicated in the pathogenesis of systemic lupus erythematosus (SLE) and interferonopathies such as Aicardi-Goutières syndrome. A recently discovered DNA-activated type I IFN pathway, cyclic GMP-AMP synthase (cGAS), has been linked to Aicardi-Goutières syndrome and mouse models of lupus. The aim of this study was to determine whether the cGAS pathway contributes to type I IFN production in patients with SLE. METHODS: SLE disease activity was measured by the Safety of Estrogens in Lupus Erythematosus National Assessment version of the Systemic Lupus Erythematosus Disease Activity Index. Expression of messenger RNA for cGAS and IFN-stimulated genes (ISGs) was determined by quantitative polymerase chain reaction analysis. Cyclic GMP-AMP (cGAMP) levels were examined by multiple reaction monitoring with ultra-performance liquid chromatography tandem mass spectrometry. RESULTS: Expression of cGAS in peripheral blood mononuclear cells (PBMCs) was significantly higher in SLE patients than in normal controls (n = 51 and n = 20 respectively; P < 0.01). There was a positive correlation between cGAS expression and the IFN score (P < 0.001). The expression of cGAS in PBMCs showed a dose response to type I IFN stimulation in vitro, consistent with it being an ISG. Targeted measurement of cGAMP by tandem mass spectrometry detected cGAMP in 15% of the SLE patients (7 of 48) but none of the normal (0 of 19) or rheumatoid arthritis (0 of 22) controls. Disease activity was higher in SLE patients with cGAMP versus those without cGAMP. CONCLUSION: Increased cGAS expression and cGAMP in a proportion of SLE patients indicates that the cGAS pathway should be considered as a contributor to type I IFN production. Whereas higher cGAS expression may be a consequence of exposure to type I IFN, detection of cGAMP in patients with increased disease activity indicates potential involvement of this pathway in disease expression.

The xanthine derivative KMUP-1 inhibits models of pulmonary artery hypertension via increased NO and cGMP-dependent inhibition of RhoA/Rho kinase.

BACKGROUND AND PURPOSE: KMUP-1 is known to increase cGMP, enhance endothelial nitric oxide synthase (eNOS) and suppress Rho kinase (ROCK) expression in smooth muscle. Here, we investigated the mechanism of action of KMUP-1 on acute and chronic pulmonary artery hypertension (PAH) in rats. EXPERIMENTAL APPROACH: We measured pulmonary vascular contractility, wall thickening, eNOS immunostaining, expressions of ROCK II, RhoA activation, myosin phosphatase target subunit 1 (MYPT1) phosphorylation, eNOS, soluble guanylyl cyclase (sGC), protein kinase G (PKG) and phosphodiesterase 5A (PDE-5A), blood oxygenation and cGMP/cAMP, and right ventricular hypertrophy (RVH) in rats. KEY RESULTS: In rings of intact pulmonary artery (PA), KMUP-1 relaxed the vasoconstriction induced by phenylephrine (10 microM) or the thromboxane A(2)-mimetic U46619 (0.5 microM). In endothelium-denuded PA rings, this relaxation was reduced. In acute PAH induced by U46619 (2.5 microg x kg(-1) x min(-1), 30 min), KMUP-1 relaxed vasoconstriction by enhancing levels of eNOS, sGC and PKG, suppressing those of PDE-5A, RhoA/ROCK II activation and MYPT1 phosphorylation, and restoring oxygenation in blood and cGMP/cAMP in plasma. Incubating smooth muscle cells from PA (PASMCs) with KMUP-1 inhibited thapsigargin-induced Ca(2+) efflux and angiotensin II-induced Ca(2+) influx. In chronic PAH model induced by monocrotaline, KMUP-1 increased eNOS and reduced RhoA/ROCK II activation/expression, PA wall thickening, eNOS immunostaining and RVH. KMUP-1 and sildenafil did not inhibit monocrotaline-induced PDE-5A expression. CONCLUSION AND IMPLICATIONS: KMUP-1 decreased PAH by enhancing NO synthesis by eNOS, with consequent cGMP-dependent inhibition of RhoA/ROCK II and Ca(2+) desensitization in PASMCs. KMUP-1 has the potential to reduce vascular resistance, remodelling and RVH in PAH.

Cyclic nucleotides and mitogen-activated protein kinases: regulation of simvastatin in platelet activation.

BACKGROUND: 3-Hydroxy-3-methyl-glutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have been widely used to reduce cardiovascular risk. These statins (i.e., simvastatin) may exert other effects besides from their cholesterol-lowering actions, including inhibition of platelet activation. Platelet activation is relevant to a variety of coronary heart diseases. Although the inhibitory effect of simvastatin in platelet activation has been studied; the detailed signal transductions by which simvastatin inhibit platelet activation has not yet been completely resolved. METHODS: The aim of this study was to systematically examine the detailed mechanisms of simvastatin in preventing platelet activation. Platelet aggregation, flow cytometric analysis, immunoblotting, and electron spin resonance studies were used to assess the antiplatelet activity of simvastatin. RESULTS: Simvastatin (20-50 microM) exhibited more-potent activity of inhibiting platelet aggregation stimulated by collagen than other agonists (i.e., thrombin). Simvastatin inhibited collagen-stimulated platelet activation accompanied by [Ca2+]i mobilization, thromboxane A2 (TxA2) formation, and phospholipase C (PLC)gamma2, protein kinase C (PKC), and mitogen-activated protein kinases (i.e., p38 MAPK, JNKs) phosphorylation in washed platelets. Simvastatin obviously increased both cyclic AMP and cyclic GMP levels. Simvastatin markedly increased NO release, vasodilator-stimulated phosphoprotein (VASP) phosphorylation, and endothelial nitric oxide synthase (eNOS) expression. SQ22536, an inhibitor of adenylate cyclase, markedly reversed the simvastatin-mediated inhibitory effects on platelet aggregation, PLCgamma2 and p38 MAPK phosphorylation, and simvastatin-mediated stimulatory effects on VASP and eNOS phosphorylation. CONCLUSION: The most important findings of this study demonstrate for the first time that inhibitory effect of simvastatin in platelet activation may involve activation of the cyclic AMP-eNOS/NO-cyclic GMP pathway, resulting in inhibition of the PLCgamma2-PKC-p38 MAPK-TxA2 cascade, and finally inhibition of platelet aggregation.

Inhibitory effects of staphylococcal enterotoxin type B on human platelet adhesion in vitro.

Septic shock was formerly recognized as a consequence of Gram-negative bacteraemia, but at present the incidence of Gram-positive sepsis seems to be more relevant, contributing for more than 50% of cases. Staphylococcal aureus can induce toxic shock in humans through the production of potent toxins termed Staphylococcal enterotoxins, from which Staphylococcal enterotoxin type B (SEB) is one of most studied. Platelets are reported to participate in pathogenesis of severe sepsis, but the exact role of platelets in this event is poorly investigated, particularly that caused by Gram-positive bacteria. Therefore, we have used the model of platelet adhesion to fibrinogen-coated plates to investigate the actions of SEB on human platelets. Ninety-six-well microtiter plates were coated with human fibrinogen (50 microg/mL), and human washed platelet suspension (6 x 10(6) platelets) was added to each well. Adherent platelets were quantified through measurement of acid phosphatase activity. Staphylococcal enterotoxin B (0.0001-30 microg/mL, incubated for 5 to 60 min) time- and dose-dependently inhibited platelet adhesion. This response was modified neither by the protein synthesis inhibitor puromycin (0.01 and 0.1 mM) nor by the superoxide scavengers superoxide dismutase (SOD, 100 units/mL) and polyethylene glycol-SOD (30 U/mL). The peroxide hydrogen (H(2)O(2)) scavenger catalase polyethylene glycol (1000 U/mL) significantly attenuated the platelet adhesion inhibition by SEB. The cAMP and cGMP levels were not changed by SEB (0.0001-30 microg/mL, 60 min). Our findings suggest that H(2)O(2) at least partly contributes to the inhibitory responses of human platelet adhesion by SEB.

[The part of the hormone-cyclase system in achieving the therapeutic effect of hydrochloric acid secretion inhibitors at the duodenal ulcer].

There was a study of changes in blood hormone levels (gastrin, insulin, cortisol) and cyclic nucleotides (cAMPh, cGMPh) in the treatment of 120 patients with duodenal ulcer with anti-secretion drugs of different mechanisms of action. Changes in hormone and cyclic nucleotide levels were discovered both directly after the administration of anti-secretion drugs and after a course of treatment with them. The data obtained increase the knowledge about the mechanisms of anti-secretion drugs action and their influence on the stomach secretion function at the duodenal ulcer.

[Role of cyclic nucleotides in formation of pathologic reactions in the immediate postoperative period]. / Rol' tsiklicheskikh nukleotidov v formirovanii patologicheskikh reaktsii v blizhaishem posleoperatsionnom periode.

Effects of anesthesia and surgery on the level of cyclic nucleotides (CN) and their role in the formation of pathological reactions are little studied. We measured plasma concentrations of CN for evaluating the quantitative and qualitative changes in adenylate-guanylate cyclase metabolism under the effect of operation and for elucidating the role of these changes in postoperative disorders of hemodynamics and gas exchange. The findings in patients with surgical diseases of the lungs (168 pts), with acquired and congenital heart diseases (193 pts), and with atherosclerotic involvement of the aorta (63 pts) were analyzed. The CN system is responsible for the pre-, intra-, and postoperative status of surgical patients, which manifests by a hypermetabolic reaction leading to an increase in the blood concentrations of cAMP and cGMP. At the initial stages this reaction is compensatory, while in the immediate postoperative period CN are involved in the pathological mechanisms leading to hemodynamic disorders.

Changes in plasma levels of cyclic nucleotides during low-density lipoprotein apheresis.

The negative charges of dextran sulfate (DS) used for low-density lipoprotein (LDL) apheresis activate the intrinsic coagulation pathway, accompanied by the production of bradykinin. This study was undertaken to see whether cyclic nucleotide plasma levels are affected by DS LDL apheresis. Previously, we showed the rise in plasma levels of prostaglandins and nitric oxide derivatives accompanied by the rise in bradykinin levels. The physiologic effects of prostaglandins and nitric oxide become manifest through the intracellular signal of cyclic nucleotides. The plasma levels of the cyclic nucleotides (cyclic adenosine monophosphate [cAMP] and cyclic guanosine monophosphate [cGMP]) were examined when either of 2 anticoagulants, heparin or nafamostat mesilate (NM), was used during DS LDL apheresis. The plasma levels of cAMP during LDL apheresis using heparin were 9.2 +/- 0.3 (mean +/- SE) 12.4 +/- 0.6, 12.0 +/- 0.5, and 12.1 +/- 0.3 pmol/ml, respectively, at the 0, 1,000, 2,000, and 3,000 ml stages. The rise in cAMP levels was suppressed during apheresis using NM. There were no significant increases in cGMP during apheresis with heparin or with NM. There were significant negative correlations between changes in cAMP and those in the blood pressure. These findings suggest that bradykinin generated during apheresis exerts some physiologic effects via activation of the adenylate cyclase dependent pathway.

Effects of short-term exercise on female platelet function during different phases of the menstrual cycle.

Previous studies have shown that premenopausal women have a low incidence of cardiovascular diseases, and that acute exercise affects male platelet function in an intensity-dependent manner. To investigate whether acute exercise affects female platelet function differently from males, sixteen sedentary women in the midfollicular phase or midluteal phase received strenuous or moderate exercise on a bicycle ergometer. Before and immediately after exercise, platelet adhesiveness, adenosine diphosphate-induced platelet aggregation and intracellular calcium concentration elevation, platelet cAMP and cGMP contents, urinary 11-dehydro-TXB2 and 6-keto-prostaglandin F1 alpha levels, and plasma nitric oxide metabolite level were determined. Our results showed no differences in exercise performance and in resting platelet function between two menstrual phases, with little change in urinary eicosanoid metabolites and platelet cAMP levels under all experimental conditions. In addition, for women in the midfollicular phase, (1) strenuous exercise increased platelet adhesiveness, adenosine-diphosphate-induced platelet aggregation, and intracellular calcium concentration elevation, whereas moderate exercise suppressed them; (2) moderate exercise enhanced plasma nitric oxide metabolite and platelet cGMP levels. In contrast, none of these platelet functions was affected by acute exercise in the midluteal phase. Therefore, we conclude that acute exercise affects female platelet function in an intensity-dependent manner in the midfollicular phase but not in the midluteal phase. The irresponsiveness of platelets to acute exercise in the luteal phase may partially explain why premenopausal women have a lower incidence of cardiovascular diseases than men.

[Action of ionizing radiation on the functional activity of lymphoid cells]. / Deistvie ioniziruiushchei radiatsii na funktsional'nuiu aktivnost' limfoidnykh kletok.

The contribution of the post-irradiation changes in cyclic nucleotides transformation to the biochemical mechanism of interphase death of irradiated cells is estimated. It is suggested that the biochemical mechanism of interphase death is complex and involves several concurrent trigger mechanisms including cyclic nucleotides regulation system.

[The biorhythmology of primary and superinvasive opisthorchiasis. Seasonal changes in the circadian activity of the cyclic nucleotides and of the key enzyme of the pentosephosphate cycle (G-6-PD) in the peripheral blood of golden hamsters]. / Bioritmologiia pervichnogo i superinvazionnogo opistorkhoza. Sezonnye izmeneniia sutochnoi aktivnosti tsiklicheskikh nukleotidov i kliuchevogo fermenta pentozo-fosfatnogo tsikla (G-6-FDG) perifericheskoi krovi zolotistykh khomiakov.

570 males of golden hamsters were divided into 3 groups: I--free from invasion, II--once infected, III--repeatedly infected. Diurnal activity of cyclic nucleotides and enzyme of pentose-phosphate cycle (G-6-PhDG) was investigated in spring, autumn, and winter at 3, 7, 11 a.m. and 3, 7, 11 p.m. The golden hamsters once infected with opisthorchiasis do not show any seasonal changes in G-6-PhDG activity, but this invasion influences the total content of protein, diurnal oscillation of which depends upon seasons. In spring time the repeated invasion induces the diurnal rhythms of G-6-PhDG and of total protein content. Diurnal stereotype of cyclic nucleotides (cGMP, cAMP) demonstrates the dependence upon seasons and invasion frequency without any changes of the average diurnal level.

[Laser irradiation: study of total effect of irradiation of the eyeball. A clinical study]. / Lazernoe izluchenie: issledovanie obshchego deistviia pri obluchenii glaznogo bloka. Klinicheskoe issledovanie.

Lipid peroxidation products, antioxidant system parameters, somatotrophic hormone, corticosteroids, fibronectin, and cyclic nucleotides were measured in the blood of 119 patients with open-angle glaucoma and mature senile cataract before and after a course of exposure of the eyeball to He-Ne laser. Statistically significant changes in the examined parameters were revealed, explaining to a great measure the antiinflammatory and vasodilating effects of laser and its ability to intensify the repair processes.

[Age-specific features of the cyclic nucleotide system in children]. / Vozrastnye osobennosti sistemy tsiklicheskikh nukleotidov u detei.

The content of cyclic nucleotides (cAMP and cGMP) in the plasma and peripheral blood leukocytes, levels of their daily urinary excretion, and the activities of adenylate cyclase and cAMP-dependent phosphodiesterase responsible for the synthesis and degradation of cAMP in the leukocytes were studied in 114 healthy children aged 0 to 15 years. The levels of cyclic nucleotides in the blood plasma and leukocytes were found to gradually increase with age, as well as urinary excretion of cAMP. Both cAMP synthesis and degradation were found intensified with age. The detected age-specific features of cyclic nucleotides are important criteria for the assessment of the development of children and their health status. The findings may be used as reference values in assessment of the status of cyclic nucleotides in children with various diseases.

[The mineralization of the regenerate and the hormonal regulation of bone formation during the treatment of a malunited diaphyseal fracture of the shin bones]. / Mineralizatsiia regenerata i gormonal'naia reguliatsiia kosteobrazovaniia pri lechenii nepravil'no srosshegosia pereloma diafiza kostei goleni.

In 68 patients with imperfectly united fracture of the crural bones who underwent treatment with the use of the Ilizarov's method, the processes of mineralization of the osseous regenerate being formed were studied. The most rapid deposition of the mineral substances was noted in gradual elimination of a deformity. In shortening of an extremity, the rate of mineralization depended on a size of the elongation performed. Increase in content of the osteotropic hormones and cyclic. nucleotides was indicative of the presence of favourable conditions for formation of osseous regenerate in correction of angular deformity by means of the Ilizarov's method.

[The effect of antidepressants on lipid metabolism and the clinical course in IHD]. / Vliianie antidepressantov na lipidnyi metabolizm i klinicheskoe techenie IBS.

The addition of antidepressants to combined treatment of IHD patients aroused not only mediated psychic benefit, but also positive shifts in metabolic and mediator regulation of chronic psychoemotional stress. Antidepressants administration results in lowering of total blood cholesterol and atherogenic lipoproteins, inhibits LPO, promotes normalization of cyclic nucleotides levels (cAMP and cGMP increase and decrease, respectively). Clinical course of the disease also improved (less frequent and severe attacks of angina pectoris and associated atypical pain syndrome, of arrhythmia paroxysms; exercise tolerance increased, hemodynamics improved). The arguments in favour of antidepressant use in coronary patients with anxiodepressive symptoms and social and psychological dysadaptation are provided.

[The mechanisms of the development of arterial hypertension in patients with chronic kidney failure treated by hemodialysis]. / Nekotorye mekhanizmy razvitiia arterial'noi gipertenzii u bol'nykh s kronicheskoi pochechnoi nedostatochnost'iu, lechennykh gemodializom.

Hypertensive patients out of 50 with chronic renal failure degree IIIA on programmed hemodialysis were divided into those with uncontrolled (group 1) and controlled (group 2) arterial hypertension. Group 1 was found to have hyperactive renin-angiotensin aldosterone system and marked unbalance in the system of cyclic nucleotides. In group 2 the activity of renin and plasma aldosterone levels were not so high. In both groups the above hormonal abnormalities followed the pattern of progressive hyperkinetic syndrome running with an inadequate fall in peripheral vascular resistance responsible for arterial hypertension in these patients.

[Role of prostaglandins and cyclic nucleotides in the mechanism of development of drug-induced thrombocytopenia]. / Rol' prostaglandinov i tsiklicheskikh nukleotidov v mekhanizme razvitiia medikamentoznoi trombotsitopenii.

The experiments on dogs have shown that at the moment of maximal thrombocytopenia, induced by using of 0.7 mg/kg rubomycin intravenous daily during 5 days, there was a sharp increase in cAMP concentration, while the content of prostaglandin E group and F2 alpha in blood decreased. Concentration of cGMP began to increase by the 10th day. We can arrive at the opinion that the rubomycin acts on the receptors of hemopoietic precursor cells' membrane. This causes the activation of adenylate-cyclase, which stimulates the formation of cAMP, causing cells' proliferation depression. This mechanism may be regarded as the restoration reaction of megakaryocyte-thrombocyte system.

[The characteristics of prostaglandin and cyclic nucleotide biosynthesis in patients with peptic ulcer and chronic atrophic gastritis during digestion]. / Osobennosti sinteza prostaglandinov i tsiklicheskikh nukleotidov u bol'nykh iazvennoi bolezn'iu i khronicheskim atroficheskim gastritom v protsesse pishchevareniia.

Prostaglandins (PG) and cyclic nucleotides (CN) were assessed radioimmunologically in the blood plasma under basal conditions and after a standard breakfast in 20 patients with duodenal ulcer, 16--with gastric body ulcer and 18 patients with atrophic gastritis. It was established that the patients showed an increased PG level, cAMP-dependent processes. Neurohumoral mechanisms of regulation of gastric secretion were abnormal.

[The role of prostaglandins in the activity of mononuclear cells in liver cirrhosis patients]. / Rol' prostaglandinov v deiatel'nosti mononuklearnykh kletok u bol'nykh tsirrozom pecheni.

The effect of prostaglandins (PG) E1, E2, F2 and prostacyclin in vitro on the content of cAMP and cGMP in mononuclear cells of the blood was studied in 17 patients with liver cirrhosis. PG synthesis by mononuclears from 3H-arachydonic acid was also evaluated. Patients with liver cirrhosis showing no disorders of PG synthesis by non-stimulated mononuclears and reduction of basal cAMP content revealed significant changes of functional responses of cyclase systems PG loads as well as a relative reduction of PG synthesis in conditions of stimulation with phytohemagglutinin and Ca A23187 ionophore. This is an important link in deadaptation of immune reactions in patients with liver cirrhosis.