cyclic-gmp and Scleroderma--Systemic

The NO/sGC/cGMP signaling cascade plays a pivotal role in regulation of cardiovascular, cardiopulmonary and cardiorenal diseases and impairment of this cascade results in severe pathologies. Therefore, pharmacological interventions, targeting this pathway are promising strategies for treating a variety of diseases. Nitrates, supplementing NO and, PDE5 inhibitors preventing cGMP degradation, are used for angina pectoris treatment and the treatment of pulmonary arterial hypertension (PAH), respectively. More recently, a new class of drugs which directly stimulate the sGC enzyme and trigger NO-independent cGMP production was introduced and termed sGC stimulators. In 2013, the first sGC stimulator, riociguat, was approved for the treatment of PAH and chronic thromboembolic pulmonary hypertension (CTEPH). Since cGMP targets multiple intracellular downstream targets, sGC stimulators have shown - beyond the well characterized vasodilatation - anti-fibrotic, anti-inflammatory and anti-proliferative effects. These additional modes of action might extend the therapeutic potential of this drug class substantially. This review summarizes the NO/sGC/cGMP signaling cascades, the discovery and the mode of action of sGC stimulators. Furthermore, the preclinical evidence and development of riociguat for the treatment of PAH and CTEPH is reviewed. Finally, a summary of the antifibrotic effects of sGC stimulators, especially the most recent finding for skin fibrosis are included which may indicate efficacy in fibrotic diseases like Systemic Sclerosis (SSc).

Topics: Cyclic GMP; Enzyme Activators; Humans; Hypertension, Pulmonary; Nitric Oxide; Pyrazoles; Pyrimidines; Rare Diseases; Scleroderma, Systemic; Soluble Guanylyl Cyclase

We have previously described the antifibrotic role of the soluble guanylate cyclase (sGC). The mode of action, however, remained elusive. In the present study, we describe a novel link between sGC signalling and transforming growth factor β (TGFβ) signalling that mediates the antifibrotic effects of the sGC.. Human fibroblasts and murine sGC knockout fibroblasts were treated with the sGC stimulator BAY 41-2272 or the stable cyclic guanosine monophosphate (cGMP) analogue 8-Bromo-cGMP and stimulated with TGFβ. sGC knockout fibroblasts were isolated from sGCI(fl/fl) mice, and recombination was induced by Cre-adenovirus. In vivo, we studied the antifibrotic effects of BAY 41-2272 in mice overexpressing a constitutively active TGF-β1 receptor.. sGC stimulation inhibited TGFβ-dependent fibroblast activation and collagen release. sGC knockout fibroblasts confirmed that the sGC is essential for the antifibrotic effects of BAY 41-2272. Furthermore, 8-Bromo-cGMP reduced TGFβ-dependent collagen release. While nuclear p-SMAD2 and 3 levels, SMAD reporter activity and transcription of classical TGFβ target genes remained unchanged, sGC stimulation blocked the phosphorylation of ERK. In vivo, sGC stimulation inhibited TGFβ-driven dermal fibrosis but did not change p-SMAD2 and 3 levels and TGFβ target gene expression, confirming that non-canonical TGFβ pathways mediate the antifibrotic sGC activity.. We elucidated the antifibrotic mode of action of the sGC that increases cGMP levels, blocks non-canonical TGFβ signalling and inhibits experimental fibrosis. Since sGC stimulators have shown excellent efficacy and tolerability in phase 3 clinical trials for pulmonary arterial hypertension, they may be further developed for the simultaneous treatment of fibrosis and vascular disease in systemic sclerosis.

Topics: Animals; Case-Control Studies; Cells, Cultured; Collagen; Cyclic GMP; Disease Models, Animal; Fibroblasts; Fibrosis; Guanylate Cyclase; Humans; In Vitro Techniques; MAP Kinase Signaling System; Mice; Mice, Knockout; Pyrazoles; Pyridines; Receptors, Cytoplasmic and Nuclear; Receptors, Transforming Growth Factor beta; Scleroderma, Systemic; Signal Transduction; Skin; Smad Proteins; Soluble Guanylyl Cyclase; Transforming Growth Factor beta

Systemic sclerosis (SSc) is a multi-organ fibrotic disease that affects the skin and various internal organs. Therapeutic strategies for tissue fibrosis have not been established; however, aberrantly activated fibroblasts in affected lesions are key targets for modulating fibrosis. Recently, increased intracellular cyclic GMP (cGMP) levels were demonstrated to improve fibrosis levels in various diseases. The purpose of this study was to assess the anti-fibrotic properties of cGMP in cultured fibroblasts from patients with SSc. The phosphodiesterase (PDE) 5 inhibitor sildenafil increased the intracellular cGMP levels in skin fibroblasts in a dose-dependent manner. Sildenafil treatment also significantly decreased the expression of several pro-fibrotic factors that were upregulated by TGF-β1 treatment in SSc skin fibroblasts. These inhibitory effects occurred via non-canonical TGF-β signaling. Our findings revealed that sildenafil might be a novel strategy to treat tissue fibrosis and vasculopathy in SSc.

Topics: Adult; Aged; Blotting, Western; Cells, Cultured; Collagen Type I; Collagen Type I, alpha 1 Chain; Connective Tissue Growth Factor; Cyclic GMP; Dose-Response Relationship, Drug; Female; Fibroblasts; Fibrosis; Humans; Male; Middle Aged; Phosphodiesterase 5 Inhibitors; Reverse Transcriptase Polymerase Chain Reaction; Scleroderma, Systemic; Sildenafil Citrate; Skin; Transforming Growth Factor beta1

To investigate the relationship between endothelium-dependent and endothelium-independent functions and the stiffness of conduit arteries as well as levels of endothelial activation markers in patients with systemic sclerosis (SSc).. Endothelium-dependent (i.e., flow-mediated) and endothelium-independent (i.e., nitroglycerin-induced) dilation of the brachial artery was measured as the percentage of change from baseline (FMD% and NTG%, respectively) in 24 SSc patients and 24 age- and sex-matched healthy controls by high-resolution ultrasound imaging. The maximum increase in systolic pressure per unit of time (dP/dt(max)), as a measure of arterial wall stiffness, was assessed in the radial artery by pulse applanation tonometry. Plasma nitrate, the most important metabolite of nitric oxide, and 24-hour urinary excretion of nitrate were measured by gas chromatography mass spectrometry. Soluble E-selectin and soluble vascular cell adhesion molecule 1 (sVCAM-1) were measured by enzyme-linked immunosorbent assay.. Brachial artery FMD% and NTG% did not differ between SSc patients and controls. Radial artery dP/dt(max) was significantly increased in the patients and correlated significantly with elevated levels of plasma nitrate and sVCAM-1. Twenty-four-hour urinary nitrate excretion tended to be elevated. Brachial artery NTG% was significantly inversely correlated with levels of plasma nitrate and soluble endothelial adhesion molecules.. The ability of the brachial arteries to dilate in response to hyperemia and nitroglycerin challenge is preserved in SSc. Stiffness of the radial artery is increased, however. Endothelial activation seems to determine the extent of the brachial artery NTG% and the radial artery dP/dt(max). The data are compatible with the hypothesis that nitrate tolerance is present in the vascular smooth muscle cells of the brachial artery wall in SSc.

Topics: Adult; Aged; Brachial Artery; Cyclic GMP; E-Selectin; Endothelium, Vascular; Female; Humans; Male; Middle Aged; Nitrates; Nitric Oxide; Radial Artery; Regional Blood Flow; Scleroderma, Systemic; Solubility; Vascular Cell Adhesion Molecule-1

To determine the relationship between vascular function and the inflammatory response in systemic sclerosis (SSc), and to investigate whether production of endothelial-derived nitric oxide (NO) is disturbed in this disease.. We measured plasma nitrate, urinary excretion of both nitrate and cGMP, and soluble adhesion molecules of endothelial origin in patients with SSc and in age- and sex-matched controls and compared these levels between groups. Additionally, we performed correlation analysis to determine how these variables were related to one another. Plasma nitrate and 24-hour-urinary excretion of nitrate in patients and controls were measured after a 72-hour nitrate-free-diet, using a gas chromatography/mass spectrometric method. Soluble adhesion molecules intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1 (sVCAM-1), and E-selectin and cytokines were measured by enzyme-linked immunosorbent assay. The expression of E-selectin was further investigated in skin biopsy specimens by immunoperoxidase staining, and the presence of inducible NO synthase by immunoblotting.. Plasma nitrate and 24-hour-urinary-excretion of cGMP were significantly elevated in patients compared with controls, while 24-hour-urinary-excretion of nitrate tended to be elevated in SSc patients. Levels of sICAM-1, sVCAM-1, and sE-selectin were significantly elevated in the patients. Levels of plasma nitrate in the patients correlated significantly with levels of sVCAM-1 (P = 0.020) and sE-selectin (P = 0.018) and approached a significant correlation with sICAM-1 (P = 0.055), suggesting that activated endothelial cells may produce plasma nitrate.. NO synthesis is elevated in SSc patients, and the activated endothelial cell is a likely site of its production.

Topics: Aged; Biopsy; Cell Adhesion Molecules; Cyclic GMP; Cytokines; E-Selectin; Endothelium, Vascular; Female; Humans; Intercellular Adhesion Molecule-1; Male; Middle Aged; Nitrates; Nitric Oxide; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Receptors, Cytokine; Scleroderma, Systemic; Skin; Solubility; Vascular Cell Adhesion Molecule-1

Levels of cAMP were decreased and cGMP increased in progressive systemic sclerosis (PSS) fibroblasts compared with normal fibroblasts. PSS cells took up unusually large quantities of Ca++. The epinephrine-induced increases in cAMP were diminished sixfold and epinephrine-induced Ca++ uptake was abnormal in PSS cells. Considerable heterogeneity was observed in rheumatoid arthritis fibroblasts. Membrane-bound abnormalities in (PSS) cells may be of importance in the defective control of collagen production in progressive systemic sclerosis.

Topics: Adolescent; Adult; Arthritis, Rheumatoid; Biological Transport; Calcium; Cells, Cultured; Collagen; Cyclic AMP; Cyclic GMP; Epinephrine; Female; Fibroblasts; Humans; Male; Middle Aged; Propranolol; Scleroderma, Systemic; Skin