Guanosine Monophosphate Research Articles

The Effect of the Combination of Ginseng, Tribulus Terrestris, and L-arginine on the Sexual Performance of Men with Erectile Dysfunction: a randomized, double-blind, parallel, and placebo-controlled clinical trial.

Nitric oxide is the most important mediator of penile erection after the onset of sexual excitement. It activates cyclic guanosine monophosphate (cGMP), increasing penile blood flow. Most pharmaceutical medications prevent enzyme phosphodiesterase type 5 (PDE-5) from breaking down cGMP, thus keeping its level high. However, due to the adverse effects of pharmacological therapies, herbal drugs that improve sexual function have gained attention recently. This study aimed to investigate the combined effects of ginseng, Tribulus terrestris, and L-arginine amino acid on the sexual performance of individuals with erectile dysfunction (ED) using the 5-item version of the International Index of Erectile Function (IIEF-5) questionnaire. Over three months, 98 men with erectile dysfunction were randomly assigned to receive either 500 mg of herbal supplements or placebo pills. Each herbal tablet contained 100 mg of protodioscin, 35 mg of ginsenosides, and 250 mg of L-arginine. The results showed that the changes in the average scores of ILEF-5 within each group before and after the intervention indicated that all parameters related to the improvement of sexual function in patients with erectile dysfunction improved in the herbal treatment group (p < 0.001). The herbal group significantly improved IIEF-5 scores in non-diabetics (p < 0.05). However, there was no significant difference in the changes of IIEF-5 scores between the two intervention and control groups in diabetic patients. In conclusion, ginseng, Tribulus terrestris, and L-arginine have properties that increase energy and strengthen sexual function, making them suitable for patients with sexual disorders.

Lipid Emulsions Inhibit Labetalol-Induced Vasodilation in the Isolated Rat Aorta.

Lipid emulsions are used as adjuvant drugs to alleviate intractable cardiovascular collapse induced by drug toxicity. We aimed to examine the effect of lipid emulsions on labetalol-induced vasodilation and the underlying mechanism in the isolated rat aorta. We studied the effects of endothelial denudation, NW-nitro-l-arginine methyl ester (l-NAME), calmidazolium, methylene blue, 1H-[1,2,4]oxadiazolo[4,3-a] quinoxalin-1-one (ODQ), and lipid emulsions on labetalol-induced vasodilation. We also evaluated the effects of lipid emulsions on cyclic guanosine monophosphate (cGMP) formation, endothelial nitric oxide synthase (eNOS) phosphorylation, and endothelial calcium levels induced by labetalol. Labetalol-induced vasodilation was higher in endothelium-intact aortas than that in endothelium-denuded aortas. l-NAME, calmidazolium, methylene blue, and ODQ inhibited labetalol-induced vasodilation in endothelium-intact aortas. Lipid emulsions inhibited labetalol-induced vasodilation in endothelium-intact and endothelium-denuded aortas. l-NAME, ODQ, and lipid emulsions inhibited labetalol-induced cGMP formation in endothelium-intact aortas. Lipid emulsions reversed the stimulatory and inhibitory eNOS (Ser1177 and Thr495) phosphorylation induced by labetalol in human umbilical vein endothelial cells and inhibited the labetalol-induced endothelial calcium increase. Moreover, it decreased labetalol concentration. These results suggest that lipid emulsions inhibit vasodilation induced by toxic doses of labetalol, which is mediated by the inhibition of endothelial nitric oxide release and reduction of labetalol concentration.

Exosome Therapy: A Novel Approach for Enhancing Estrogen Levels in Perimenopause.

Perimenopause significantly impacts women's health globally, often managed with hormone replacement therapy (HRT) despite the associated risks. This study explores a novel alternative exosome therapy, aimed at stimulating estrogen production in ovarian tissues, thus offering a potential non-hormonal treatment for perimenopausal symptoms. Employing ex vivo methodologies, ovarian cortex specimens from perimenopausal women were treated with exosomes derived from human umbilical cord mesenchymal stem cells and cultured under specific conditions (patent number: PCT/US2022/073467). The exosomes were produced under cyclic guanosine monophosphate (cGMP) conditions, ensuring high safety standards. Estrogen levels were quantified using enzyme-linked immunosorbent assay (ELISA), and gene expression changes in estrogen and follicle-stimulating hormone (FSH) receptors were assessed via quantitative polymerase chain reaction (PCR). Immunohistochemistry (IHC) was utilized to evaluate cellular proliferation and apoptotic markers. The results indicated a significant increase in estrogen levels and estrogen receptor-alpha (Erα) expression in treated tissues compared to controls. Additionally, a decrease in apoptotic markers and an increase in cellular proliferation markers were observed. These findings suggest that exosome therapy can effectively enhance estrogen production and modulate receptor sensitivity in perimenopausal ovarian tissues. This approach could serve as a safer alternative to HRT, aligning with the body's natural regulatory mechanisms and potentially offering a more effective treatment option for managing perimenopausal symptoms.

Naringenin modulates the NO‑cGMP‑PKG signaling pathway by binding to AKT to enhance osteogenic differentiation in hPDLSCs.

Naringenin (NAR) is a prominent flavanone that has been recognized for its capacity to promote the osteogenic differentiation of human periodontal ligament stem cells (hPDLSCs). The present study aimed to explore how NAR promotes the osteogenic differentiation of hPDLSCs and to assess its efficacy in repairing alveolar bone defects. For this purpose, a protein‑protein interaction network of NAR action was established by mRNA sequencing and network pharmacological analysis. Gene and protein expression levels were evaluated by reverse transcription‑quantitative and western blotting. Alizarin red and alkaline phosphatase staining were also employed to observe the osteogenic capacity of hPDLSCs, and immunofluorescence was used to examine the co‑localization of NAR molecular probes and AKT in cells. The repair of mandibular defects was assessed by micro‑computed tomography (micro‑CT), Masson staining and immunofluorescence. Additionally, computer simulation docking software was utilized to determine the binding affinity of NAR to the target protein, AKT. The results demonstrated that activation of the nitric oxide (NO)‑cyclic guanosine monophosphate (cGMP)‑protein kinase G (PKG) signaling pathway could promote the osteogenic differentiation of hPDLSCs. Inhibition of AKT, endothelial nitric oxide synthase and soluble guanylate cyclase individually attenuated the ability of NAR to promote the osteogenic differentiation of hPDLSCs. Micro‑CT and Masson staining revealed that the NAR gavage group exhibited more new bone formation at the defect site. Immunofluorescence assays confirmed the upregulated expression of Runt‑related transcription factor 2 and osteopontin in the NAR gavage group. In conclusion, the results of the present study suggested that NAR promotes the osteogenic differentiation of hPDLSCs by activating the NO‑cGMP‑PKG signaling pathway through its binding to AKT.

NO-cGMP-K+ Channels Pathways Participate in the Antihypertensive Effects of Attalea phalerata Martius ex Spreng Oil-Loaded Nanocapsules.

Attalea phalerata Martius ex Spreng is a palm tree that is widely distributed in the Central-West region of Brazil. In this study, we investigated whether the oil-loaded nanocapsules of A. phalerata (APON) have acute and long-lasting antihypertensive effects in male spontaneously hypertensive rats (SHR), as well as explored the underlying molecular mechanisms. APON was prepared using the interfacial polymer deposition method. The particle size, polydispersity index, and zeta potential were investigated using dynamic and electrophoretic light scattering. The antihypertensive effects of APON (administered at doses of 1, 3, and 10 mg/kg) were evaluated after acute intraduodenal administration and after 7 days of oral treatment. To investigate the molecular pathways involved, we used pharmacological antagonists and inhibitors that target prostaglandin/cyclic adenosine monophosphate, nitric oxide/cyclic guanosine monophosphate, and potassium channels. Both acute and prolonged administration of APON (at doses of 3 and 10 mg/kg) resulted in a significant reduction in systolic, diastolic, and mean arterial pressure. Prior treatment with a non-selective nitric oxide synthase inhibitor (Nω-nitro-L-arginine methyl ester), guanylyl cyclase inhibitor (methylene blue), or non-selective calcium-sensitive K+ channel blocker (tetraethylammonium) abolished the antihypertensive effects of APON. Our study showed that A. phalerata oil-loaded nanocapsules have a significant antihypertensive effect in SHR after both short-term and long-term (7-day) use. This effect seems to rely on the vascular endothelium function and involves the NO-cGMP-K+ channel pathway. This research suggests a new direction for future studies to definitively prove the therapeutic benefits of APON in treating cardiovascular disease.

Graphene Far-Infrared Irradiation Can Effectively Relieve the Blood Pressure Level of Rat Untr-HT in Primary Hypertension.

Graphene, when electrified, generates far-infrared radiation within the wavelength range of 4 μm to 14 μm. This range closely aligns with the far-infrared band (3 μm to 15 μm), which produces unique physiological effects. Contraction and relaxation of vascular smooth muscle play a significant role in primary hypertension, involving the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate pathway and the renin-angiotensin-aldosterone system. This study utilized spontaneously hypertensive rats (SHRs) as an untr-HT to investigate the impact of far-infrared radiation at specific wavelengths generated by electrified graphene on vascular smooth muscle and blood pressure. After 7 weeks, the blood pressure of the untr-HT group rats decreased significantly with a notable reduction in the number of vascular wall cells and the thickness of the vascular wall, as well as a decreased ratio of vessel wall thickness to lumen diameter. Additionally, blood flow perfusion significantly increased, and the expression of F-actin in vascular smooth muscle myosin decreased significantly. Serum levels of angiotensin II (Ang-II) and endothelin 1 (ET-1) were significantly reduced, while nitric oxide synthase (eNOS) expression increased significantly. At the protein level, eNOS expression decreased significantly, while α-SMA expression increased significantly in aortic tissue. At the gene level, expressions of eNOS and α-SMA in aortic tissue significantly increased. Furthermore, the content of nitric oxide (NO) in the SHR's aortic tissue increased significantly. These findings confirm that graphene far-infrared radiation enhances microcirculation, regulates cytokines affecting vascular smooth muscle contraction, and modifies vascular morphology and smooth muscle phenotype, offering relief for primary hypertension.

(007) TESTOSTERONE POSITIVELY REGULATES ADENOSINE-INDUCED RELAXATION IN THE VAGINA: AN EXPERIMENTAL STUDY IN RATS

Abstract Introduction It has been previously demonstrated that testosterone (T) has a pivotal role in controlling vaginal relaxation through the related molecular machinery, i.e., improving the nitric oxide (NO)/protein kinase G (PKG)/cyclic guanosine monophosphate (cGMP) vaginal signaling and maintaining the integrity of the muscular wall. Adenosine (ADO) is a purinergic neuromodulator that, in the male, shows a positive effect on penile erection by controlling smooth muscle relaxation and local blood flow increase. However, the role, if any, of T on the ADO-induced relaxation signaling is yet to be investigated. Objective The aim of this study was to evaluate the effect of sex steroids on ADO-mediated vaginal relaxation using a validated animal model of ovariectomized (OVX) and sex steroid supplemented Sprague-Dawley rats. Methods Subgroups of OVX rats were treated with 17β-estradiol (E2; 10 mg/kg/die), testosterone (T; 30 mg/kg/week), or testosterone and letrozole (T+L, 2.5 mg/kg/die) for 6 weeks. The experimental groups were compared with a group of intact rats. In vitro contractility studies were performed on noradrenaline (NA) pre-contracted distal vaginal strips, isolated from each experimental group, stimulated with increasing doses of ADO (1 μM - 1 mM), with or without NO-synthase inhibitor L-NAME (100 μM) pretreatment, or treated with ADORA2A selective agonist CGS21680 (10 Pm-100 μM). Messenger ribonucleic acid (mRNA) isolated from vaginal tissue was analyzed by semi-quantitative Reverse Transcriptase-Polymerase Chain Reaction. Results The results showed that OVX resulted in a decreased responsiveness to ADO, completely restored by T supplementation, with or without letrozole. In contrast, E2 did not affect the hyporesponsiveness to ADO in OVX rats. Likewise, ADO induced dose-dependent relaxation was significantly reduced by in vitro L-NAME (100 μM) only in the OVX animals treated with T or T+L. Accordingly, vagina expressed all ADO receptors (ADORA1, ADORA2A, ADORA2B, ADORA3) mRNAs, with pro-relaxant ADORA2A (ADO receptor coupled to adenylyl cyclase activation) being significantly modulated by hormonal treatments: OVX significantly reduced ADORA2A mRNA expression, an effect counteracted by either T or T+L administration, but not by E2. These data are supported by the observed T-induced upregulation of cyclic adenosine monophosphate (cAMP)-dependent genes, where T, but not E2, treatment upregulated the mRNA expression of the ubiquitous isoform of ADCY (ADCY4), protein kinase A (PKA) catalytic subunit b (PKAcb), PKA regulatory subunit 2b (PKAr2b) and cAMP responsive element modulator (CREM). Finally, as further demonstration of the functional activity of ADO signaling in distal vagina, stimulation by increasing doses of CGS21680, a selective agonist of ADORA2A receptor, enhanced the relaxant effect induced by T and T+L treatments but not by E2. Conclusions Our data demonstrated for the first time a novel ADO-mediated relaxant mechanism in vagina and suggested that T positively modulates the responsiveness to ADO stimulation, thus confirming this process as a major player in the relaxant mechanism regulation of muscle contractility in vagina. Disclosure No.

Vasorelaxant effects of biochemical constituents of various medicinal plants and their benefits in diabetes.

Endothelial function plays a pivotal role in cardiovascular health, and dysfunction in this context diminishes vasorelaxation concomitant with endothelial activity. The nitric oxide-cyclic guanosine monophosphate pathway, prostacyclin-cyclic adenosine monophosphate pathway, inhibition of phosphodiesterase, and the opening of potassium channels, coupled with the reduction of calcium levels in the cell, constitute critical mechanisms governing vasorelaxation. Cardiovascular disease stands as a significant contributor to morbidity and mortality among individuals with diabetes, with adults afflicted by diabetes exhibiting a heightened cardiovascular risk compared to their non-diabetic counterparts. A plethora of medicinal plants, characterized by potent pharmacological effects and minimal side effects, holds promise in addressing these concerns. In this review, we delineate various medicinal plants and their respective biochemical constituents, showcasing concurrent vasorelaxant and anti-diabetic activities.

C-type natriuretic peptide/cGMP/FoxO3 signaling attenuates hyperproliferation of pericytes from patients with pulmonary arterial hypertension

Pericyte dysfunction, with excessive migration, hyperproliferation, and differentiation into smooth muscle-like cells contributes to vascular remodeling in Pulmonary Arterial Hypertension (PAH). Augmented expression and action of growth factors trigger these pathological changes. Endogenous factors opposing such alterations are barely known. Here, we examine whether and how the endothelial hormone C-type natriuretic peptide (CNP), signaling through the cyclic guanosine monophosphate (cGMP) -producing guanylyl cyclase B (GC-B) receptor, attenuates the pericyte dysfunction observed in PAH. The results demonstrate that CNP/GC-B/cGMP signaling is preserved in lung pericytes from patients with PAH and prevents their growth factor-induced proliferation, migration, and transdifferentiation. The anti-proliferative effect of CNP is mediated by cGMP-dependent protein kinase I and inhibition of the Phosphoinositide 3-kinase (PI3K)/AKT pathway, ultimately leading to the nuclear stabilization and activation of the Forkhead Box O 3 (FoxO3) transcription factor. Augmentation of the CNP/GC-B/cGMP/FoxO3 signaling pathway might be a target for novel therapeutics in the field of PAH.

Advances in human glutamine-hydrolyzing synthetases and their therapeutic potential

Bifunctional enzymes, characterized by their dual active sites, enable efficient chemical conversion and substrate channeling using elegant coupling mechanisms to coordinate the two active sites. In humans, several bifunctional enzymes synthesize de novo carbon-nitrogen bonds by hydrolyzing glutamine and ATP in distinct active sites. Notable examples include guanosine monophosphate synthetase, cytidine triphosphate synthetase, phosphoribosylformyl-glycinamidine synthase, asparagine synthetase, and nicotinamide adenine dinucleotide synthetase. A more complex example of multifunctional glutamine-hydrolyzing synthetases in humans is carbamoyl phosphate synthetase. These enzymes are crucial for the biosynthesis of amino acids, nucleic acids, and co-factors, thereby playing pivotal roles in human health. This review delineates recent progress in understanding the structural characteristics, regulatory mechanisms, and disease relevance of glutamine-hydrolyzing synthetases in humans. Insights into their catalysis and activity regulation offer potential pathways for developing novel therapeutics.

Research progress on phosphodiesterase 4 inhibitors in central nervous system diseases.

Phosphodiesterases (PDE) are involved in the regulation of cellular physiological processes and neurological functions, including neuronal plasticity, synapto-genesis, synaptic transmission, memory formation and cognitive functions by catalyzing the hydrolysis of intracellular cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP). Many basic and clinical studies have shown that PDE4 inhibitors block or ameliorate the occurrence and development of central nervous system (CNS) diseases by inhibiting cAMP hydrolysis, increasing cAMP content and enhancing its downstream effects. PDE4 inhibitors have long-term potentiation effect, which can enhance phosphorylation of cAMP response element binding protein (CREB) and upregulate expression of memory related Arc genes in hippocampal neurons, thereby improving cognitive impairment and Alzheimer's disease-like symptoms. They can also delay the occurrence and development of Parkinson's disease by reducing the cytotoxicity induced by α-syn and increasing the effect of miR-124-3p on cell functions. Alteration of PDE4 activity is the molecular basis for psychosis and some cognitive disorders, therefore it is considered as a therapeutic target for schizophrenia. PDE4 inhibitors play a role in depression by inhibiting the advanced glycation end product receptor (RAGE), TLR4 and NLRP3 pathways in the hippocampus, reducing the activation of microglia and the production of IL-1β, down-regulating HMGB1/RAGE signaling pathway and inhibiting inflammatory factors. PDE4 inhibitor plays a role in the treatment of autism spectrum disorder by reducing the damage of cerebellar glial cells, increasing nociceptive threshold, and improving mutual learning and memory deficits. PDE4 inhibitors might be used in the treatment of fragile X syndrome by regulating the level of cAMP and affecting the expression of fragile X mental retardation protein (FMRP). PDE4 inhibitors can also promote the differentiation of oligodendrocyte progenitor cells and enhance myelination, which has potential in the treatment of multiple sclerosis. PDE4 is also related to bipolar disorder, which may be one of the therapeutic targets. At present, several PDE4 inhibitors are in clinical trials for the treatment of CNS diseases. This article reviews and discusses the progress on basic research and clinical trials of PDE4 inhibitors in CNS diseases, providing a reference for the prevention and treatment of CNS diseases and the development of new drugs.

The cGAS-STING-interferon regulatory factor 7 pathway regulates neuroinflammation in Parkinson's disease.

JOURNAL/nrgr/04.03/01300535-202508000-00026/figure1/v/2024-09-30T120553Z/r/image-tiff Interferon regulatory factor 7 plays a crucial role in the innate immune response. However, whether interferon regulatory factor 7-mediated signaling contributes to Parkinson's disease remains unknown. Here we report that interferon regulatory factor 7 is markedly up-regulated in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced mouse model of Parkinson's disease and co-localizes with microglial cells. Both the selective cyclic guanosine monophosphate adenosine monophosphate synthase inhibitor RU.521 and the stimulator of interferon genes inhibitor H151 effectively suppressed interferon regulatory factor 7 activation in BV2 microglia exposed to 1-methyl-4-phenylpyridinium and inhibited transformation of mouse BV2 microglia into the neurotoxic M1 phenotype. In addition, siRNA-mediated knockdown of interferon regulatory factor 7 expression in BV2 microglia reduced the expression of inducible nitric oxide synthase, tumor necrosis factor α, CD16, CD32, and CD86 and increased the expression of the anti-inflammatory markers ARG1 and YM1. Taken together, our findings indicate that the cyclic guanosine monophosphate adenosine monophosphate synthase-stimulator of interferon genes-interferon regulatory factor 7 pathway plays a crucial role in the pathogenesis of Parkinson's disease.

Nucleotide‐Based Carbon Dot‐Assisted Synthesis of High Surface Area Porous α‐Ni(OH)2 as an Efficient Battery‐Type Supercapacitor Electrode

Herein, a method for synthesizing highly porous single phase of α‐Ni(OH)2 via hydrothermal route is presented. Nitrogen‐ and phosphorous‐functionalized carbon dots (N,P‐CDGMP) are first synthesized by thermal refluxing of 1,5′‐guanosine monophosphate (GMP) in ethylene glycol. Then Ni(OH)2 is synthesized in the presence of N,P‐CDGMP by hydrothermal method. Microflower‐like morphology of porous nanocomposite of Ni(OH)2‐[N,P‐CDGMP] with significantly enhanced Brunauer–Emmett–Teller surface area (454 m2 g−1) is formed, which is 32 times higher than that of the pristine Ni(OH)2. The cyclic voltammetry plot suggests battery‐type supercapacitor with a specific capacity of 632 C g−1, which is 6 times higher than the pristine Ni(OH)2 (107 C g−1). The enhanced specific capacity of Ni(OH)2‐[N,P‐CDGMP] is attributable to better intercalation–deintercalation of electrolyte ions in the suitable pore volumes. Electrode kinetic studies measured at a scan rate of 0.005 V s−1 suggest that about 86% of charge is stored via diffusion‐controlled process and the charge storage by surface‐controlled capacitive process is higher at higher scan rate (e.g., at 0.1 V s−1). The application of Ni(OH)2‐[N,P‐CDGMP] is demonstrated by fabricating a hybrid supercapacitor device Ni(OH)2‐[N,P‐CDGMP]//porous activated carbon from eucalyptus wood. The retention of specific capacitance of the device is 75% after 3000 cycles with maximum energy density of 31 Wh kg−1 and power density of 0.76 kW kg−1.

Heme pocket modulates protein conformation and diguanylate cyclase activity of a tetrameric globin coupled sensor

Bacteria use the second messenger cyclic dimeric guanosine monophosphate (c-di-GMP) to control biofilm formation and other key phenotypes in response to environmental signals. Changes in oxygen levels can alter c-di-GMP signaling through a family of proteins termed globin coupled sensors (GCS) that contain diguanylate cyclase domains. Previous studies have found that GCS diguanylate cyclase activity is controlled by ligand binding to the heme within the globin domain, with oxygen binding resulting in the greatest increase in catalytic activity. Herein, we present evidence that heme-edge residues control O2-dependent signaling in PccGCS, a GCS protein from Pectobacterium carotovorum, by modulating heme distortion. Using enzyme kinetics, resonance Raman spectroscopy, small angle X-ray scattering, and multi-wavelength analytical ultracentrifugation, we have developed an integrated model of the full-length PccGCS tetramer and have identified conformational changes associated with ligand binding, heme conformation, and cyclase activity. Taken together, these studies provide new insights into the mechanism by which O2 binding modulates activity of diguanylate cyclase-containing GCS proteins.

The activation of Chlamydomonas reinhardtii alpha amylase 2 by glutamine requires its N-terminal aspartate kinase-chorismate mutase-tyrA (ACT) domain.

The coordination of assimilation pathways for all the elements that make up cellular components is a vital task for every organism. Integrating the assimilation and use of carbon (C) and nitrogen (N) is of particular importance because of the high cellular abundance of these elements. Starch is one of the most important storage polymers of photosynthetic organisms, and a complex regulatory network ensures that biosynthesis and degradation of starch are coordinated with photosynthetic activity and growth. Here, we analyzed three starch metabolism enzymes of Chlamydomonas reinhardtii that we captured by a cyclic guanosine monophosphate (cGMP) affinity chromatography approach, namely, soluble starch synthase STA3, starch-branching enzyme SBE1, and α-amylase AMA2. While none of the recombinant enzymes was directly affected by the presence of cGMP or other nucleotides, suggesting an indirect binding to cGMP, AMA2 activity was stimulated in the presence of L-glutamine (Gln). This activating effect required the enzyme's N-terminal aspartate kinase-chorismate mutase-tyrA domain. Gln is the first N assimilation product and not only a central compound for the biosynthesis of N-containing molecules but also a recognized signaling molecule for the N status. Our observation suggests that AMA2 might be a means to coordinate N and C metabolism at the enzymatic level, increasing the liberation of C skeletons from starch when high Gln levels signal an abundance of assimilated N.

Soluble guanylate cyclase stimulator as an emerging therapeutic option in the management of arrhythmias in heart failure rat model

Abstract Funding Acknowledgements Type of funding sources: Foundation. Main funding source(s): This research was supported by VEGA grant no. 2/0002/20 and 2/0006/23, the Slovak Research and Development Agency under contract no. 21-0410, European Regional Development Fund: ITMS2014+: 313011AVG3. This research was also partially supported by the Ministry of Health of the Czech Republic within the project for the development of the research organization [grant number 00023001 (IKEM)—institutional support] and also supported by the project National Institute for Research of Metabolic and Cardiovascular Diseases (Program EXCELES, Project No. LX22NPO5104)—Funded by the European Union—Next Generation EU Heart failure (HF) is a complex clinical syndrome characterized by a decrease in the efficiency of the heart pump, leading to a decline in hemodynamic status and cardiac remodelling, that can contribute to the formation of a substrate for arrhythmias. Antiarrhythmic drug therapy is still suboptimal and current therapies are not efficacious enough. The purpose of the current study was therefore to examine the efficiency of nitric oxide (NO)/soluble guanylyl cyclase (sGC)/cyclic guanosine monophosphate (cGMP) stimulator. We used as an experimental model male hypertensive Ren-2 transgenic rats (TGR, n = 16), normotensive Hannover Sprague–Dawley rats (HSD, n = 17), and a rat model of HF surgically induced by aortocaval fistula (ACF) in rats of both strains (n = 27). After ACF induction were rats treated by sGC stimulator BAY41-8543 (3 mg/kg/day for 30 weeks) alone or combined with angiotensin-converting enzyme inhibitor (ACEi) Trandolapril (0.25 mg/kg/day for 30 weeks). Age of the animals at the end of the experiment was 40 weeks. Left ventricle tissue and plasma samples were used for further analyses. Treatment by sGC stimulator significantly decreased rats' mortality, and systolic blood pressure, and significantly increased levels of antioxidant enzyme superoxide dismutase 1, matrix metalloproteinase 2, total and phosphorylated connexin 43 as well as protein kinase C epsilon, implicated in remodelling of extracellular matrix and intercellular communication, in the left ventricle of TGR rats. Application of sGC stimulator slightly normalized elevated collagen deposition and hydroxyproline content in the left ventricular tissue of TGR rats. Unfortunately, we did not observe any effect of the sGC stimulator in the TGR ACF group. These results support the hypothesis that sGC stimulators might represent a class of drugs suitable for combating heart failure with partially anti-arrhythmic potential, but further studies are needed.

Involvement of catecholaminergic and nitric oxide–cGMP pathways in the antidepressant-like effects of hydroethanolic leaf extract of Morinda Longiflora G. Don in Mice

Depression is a major world health issue. Though conventional antidepressants are employed for its management, they are fraught with inconsistent efficacy and untoward side effects. Therefore, finding alternative medicines for depression treatment is critical. The present study evaluated the possible antidepressant-like properties of hydroethanolic leaf extract of Morinda longiflora (MLE) in animal models. Acute animal models—Forced swim (FST) and tail suspension tests (TST)—as well as a chronic model, open space swim test, were used to establish antidepressant-like activity. The open field test was performed to exclude confounding psychostimulatory effects. Attempts were also made to investigate the possible underlying mechanism(s) of the antidepressant-like action of MLE. Oral treatment with MLE (30–300 mg/kg) significantly decreased the duration of immobility in the TST and FST. Also, treatment of mice with para-chlorophenylalanine (PCPA, 300 mg/kg, i.p.) failed to reverse the reduction in immobility duration induced by MLE. Furthermore, after treating mice with reserpine (1 mg/kg), α-methyl-p-tyrosine (AMPT, 100 mg/kg, i.p.), or both drugs combined, the reduction in immobility duration caused by MLE was reversed. Again, the anti-immobility actions produced by the extract were significantly reversed by l-arginine, sildenafil, haloperidol and prazosin but not propranolol, yohimbine or cyproheptadine. Pre-treatment of mice with l-NAME and methylene blue potentiated the anti-immobility action produced by the extract. The extract markedly reduced the duration of immobility in the OSST model. However, the extract (30–300 mg/kg) had no significant effect on the total distance travelled in the open field test. In conclusion, the current findings suggest that hydroethanolic leaf extract of Morinda longiflora has significant antidepressant-like activity and may involve catecholaminergic and nitric oxide-cyclic guanosine monophosphate pathways.

Safety, tolerability, pharmacokinetics, and pharmacodynamics of BI 685509, a soluble guanylyl cyclase activator, in healthy volunteers: Results from two randomized controlled trials

This study evaluated the safety, tolerability, pharmacokinetics, and pharmacodynamics of BI 685509 after oral single rising doses (SRDs) or multiple rising doses (MRDs) in healthy volunteers. In the SRD trial (NCT02694354; February 29, 2016), within each of the three dose groups (DGs), six subjects received BI 685509 (1.0, 2.5, or 5.0 mg) and two received placebo (N = 24). In the MRD trial (NCT03116906; April 17, 2017), within each of the five DGs, nine subjects received BI 685509 (uptitrated to 1 mg once daily [qd; DG1], 2.5 mg twice daily [DG2], 5.0 mg qd [DG3]; 3.0 mg three times daily [tid; DG4] or 4.0 mg tid [DG5]) and three received placebo, for 14–17 days (N = 60). In the SRD trial, 7/24 subjects (29.2%) had ≥ 1 adverse event (AE), most frequently orthostatic dysregulation (n = 4). In the MRD trial, 26/45 subjects (57.8%) receiving BI 685509 had ≥ 1 AE, most frequently orthostatic dysregulation and fatigue (each n = 12). Tolerance development led to a marked decrease in orthostatic dysregulation events (DG3). BI 685509 was rapidly absorbed after oral administration, and exposure increased in a dose-proportional manner after single doses. Multiple dosing resulted in near–dose-proportional increase in exposure and limited accumulation. BI 685509 pharmacokinetics appeared linear with time; steady state occurred 3–5 days after each multiple-dosing period. Increased plasma cyclic guanosine monophosphate and decreased blood pressure followed by a compensatory increase in heart rate indicated target engagement. BI 685509 was generally well tolerated; orthostatic dysregulation may be appropriately countered by careful uptitration.

The Construction and Application of a New Screening Method for Phosphodiesterase Inhibitors.

Phosphodiesterases (PDEs), a superfamily of enzymes that hydrolyze cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), are recognized as a therapeutic target for various diseases. However, the current screening methods for PDE inhibitors usually experience problems due to complex operations and/or high costs, which are not conducive to drug development in respect of this target. In this study, a new method for screening PDE inhibitors based on GloSensor technology was successfully established and applied, resulting in the discovery of several novel compounds of different structural types with PDE inhibitory activity. Compared with traditional screening methods, this method is low-cost, capable of dynamically detecting changes in substrate concentration in live cells, and can be used to preliminarily determine the type of PDEs affected by the detected active compounds, making it more suitable for high-throughput screening for PDE inhibitors.

A Label-Free Approach for Relative Spatial Quantitation of c-di-GMP in Microbial Biofilms.

Microbial biofilms represent an important lifestyle for bacteria and are dynamic three-dimensional structures. Cyclic dimeric guanosine monophosphate (c-di-GMP) is a ubiquitous signaling molecule that is known to be tightly regulated with biofilm processes. While measurements of global levels of c-di-GMP have proven valuable toward understanding the genetic control of c-di-GMP production, there is a need for tools to observe the local changes of c-di-GMP production in biofilm processes. We have developed a label-free method for the direct detection of c-di-GMP in microbial colony biofilms using matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI). We applied this method to the enteric pathogen Vibrio cholerae, the marine symbiont V. fischeri, and the opportunistic pathogen Pseudomonas aeruginosa PA14 and detected spatial and temporal changes in c-di-GMP signal that accompanied genetic alterations in factors that synthesize and degrade the compound. We further demonstrated how this method can be simultaneously applied to detect additional metabolites of interest from a single sample.