BAY 41-2272 inhibits the development of chronic hypoxic pulmonary hypertension in rats

Endothelial and Vascular Smooth Muscle Dysfunction in Hypertension

The development of essential hypertension involves several factors. Vascular dysfunction, characterized by endothelial dysfunction, low-grade inflammation and structural remodeling, plays an important role in the initiation and maintenance of essential hypertension. Although the mechanistic pathways by which essential hypertension develops are poorly understood, several pharmacological classes available on the clinical settings improve blood pressure by interfering in the cardiac output and/or vascular function. This review is divided in two major sections. The first section depicts the major molecular pathways as renin angiotensin aldosterone system (RAAS), endothelin, nitric oxide signalling pathway and oxidative stress in the development of vascular dysfunction. The second section describes the role of some pharmacological classes such as i) RAAS inhibitors, ii) dual angiotensin receptor-neprilysin inhibitors, iii) endothelin-1 receptor antagonists, iv) soluble guanylate cyclase modulators, v) phosphodiesterase type 5 inhibitors and vi) sodium-glucose cotransporter 2 inhibitors in the context of hypertension. Some classes are already approved in the treatment of hypertension, but others are not yet approved. However, due to their potential benefits these classes were included.

Cystamine Treatment Fails to Prevent the Development of Pulmonary Hypertension in Chronic Hypoxic Rats

INTRODUCTION

Pulmonary hypertension is characterized by vasoconstriction and remodeling of pulmonary arteries, leading to right ventricular hypertrophy and failure. We have previously found upregulation of transglutaminase 2 (TG2) in the right ventricle of chronic hypoxic rats. The hypothesis of the present study was that treatment with the transglutaminase inhibitor, cystamine, would inhibit the development of pulmonary arterial remodeling, pulmonary hypertension, and right ventricular hypertrophy.

METHODS

Effect of cystamine on transamidase activity was investigated in tissue homogenates. Wistar rats were exposed to chronic hypoxia and treated with vehicle, cystamine (40 mg/kg/day in mini-osmotic pumps), sildenafil (25 mg/kg/day), or the combination for 2 weeks.

RESULTS

Cystamine concentration-dependently inhibited TG2 transamidase activity in liver and lung homogenates. In contrast to cystamine, sildenafil reduced right ventricular systolic pressure and hypertrophy and decreased pulmonary vascular resistance and muscularization in chronic hypoxic rats. Fibrosis in the lung tissue decreased in chronic hypoxic rats treated with cystamine. TG2 expression was similar in the right ventricle and lung tissue of drug and vehicle-treated hypoxic rats.

DISCUSSION/CONCLUSIONS

Cystamine inhibited TG2 transamidase activity, but cystamine failed to prevent pulmonary hypertension, right ventricular hypertrophy, and pulmonary arterial muscularization in the chronic hypoxic rat.

Changes in the nitric oxide pathway of the pulmonary vasculature after exposure to hypoxia in swine model of neonatal pulmonary vascular disease

Neonatal pulmonary vascular disease (PVD) is increasingly recognized as a disease that complicates the cardiopulmonary adaptations after birth and predisposes to long-term cardiopulmonary disease. There is growing evidence that PVD is associated with disruptions in the nitric oxide (NO)-cGMP-phosphodiesterase 5 (PDE5) pathway. Examination of the functionality of different parts of this pathway is required for better understanding of the pathogenesis of neonatal PVD. For this purpose, the role of the NO-cGMP-PDE5 pathway in regulation of pulmonary vascular function was investigated in vivo, both at rest and during exercise, and in isolated pulmonary small arteries in vitro, in a neonatal swine model with hypoxia-induced PVD. Endothelium-dependent vasodilatation was impaired in piglets with hypoxia-induced PVD both in vivo at rest and in vitro. Moreover, the responsiveness to the NO-donor SNP was reduced in hypoxia-exposed piglets in vivo, while the relaxation to SNP and 8-bromo-cyclicGMP in vitro were unaltered. Finally, PDE5 inhibition-induced pulmonary vasodilatation was impaired in hypoxia-exposed piglets both in vitro and in vivo at rest. During exercise, however, the pulmonary vasodilator effect of PDE5 inhibition was significantly larger in hypoxia-exposed as compared to normoxia-exposed piglets. In conclusion, the impaired endothelium-dependent vasodilatation in piglets with hypoxia-induced PVD was accompanied by reduced responsiveness to NO, potentially caused by altered sensitivity and/or activity of soluble guanylyl cyclase (sGC), resulting in an impaired cGMP production. Our findings in a newborn animal model for neonatal PVD suggests that sGC stimulators/activators may be a novel treatment strategy to alleviate neonatal PVD.

Discovery and development of sGC stimulators for the treatment of pulmonary hypertension and rare diseases

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).

Effect of Riociguat and Sildenafil on Right Heart Remodeling and Function in Pressure Overload Induced Model of Pulmonary Arterial Banding

Pulmonary arterial hypertension (PAH) is a progressive disorder characterized by remodeling of the pulmonary vasculature and a rise in right ventricular (RV) afterload. The increased RV afterload leads to right ventricular failure (RVF) which is the reason for the high morbidity and mortality in PAH patients. The objective was to evaluate the therapeutic efficacy and antiremodeling potential of the phosphodiesterase type 5 (PDE5) inhibitor sildenafil and the soluble guanylate cyclase stimulator riociguat in a model of pressure overload RV hypertrophy induced by pulmonary artery banding (PAB). Mice subjected to PAB, one week after surgery, were treated with either sildenafil (100 mg/kg/d, n = 5), riociguat (30 mg/kg/d, n = 5), or vehicle (n = 5) for 14 days. RV function and remodeling were assessed by right heart catheterization, magnetic resonance imaging (MRI), and histomorphometry. Both sildenafil and riociguat prevented the deterioration of RV function, as determined by a decrease in RV dilation and restoration of the RV ejection fraction (EF). Although both compounds did not decrease right heart mass and cellular hypertrophy, riociguat prevented RV fibrosis induced by PAB. Both compounds diminished TGF-beta1 induced collagen synthesis of RV cardiac fibroblasts in vitro. Treatment with either riociguat or sildenafil prevented the progression of pressure overload-induced RVF, representing a novel therapeutic approach.

The principal pathways involved in the in vivo modulation of hypoxic pulmonary vasoconstriction, pulmonary arterial remodelling and pulmonary hypertension

Hypoxic pulmonary vasoconstriction (HPV) serves to optimize ventilation-perfusion matching in focal hypoxia and thereby enhances pulmonary gas exchange. During global hypoxia, however, HPV induces general pulmonary vasoconstriction, which may lead to pulmonary hypertension (PH), impaired exercise capacity, right-heart failure and pulmonary oedema at high altitude. In chronic hypoxia, generalized HPV together with hypoxic pulmonary arterial remodelling, contribute to the development of PH. The present article reviews the principal pathways in the in vivo modulation of HPV, hypoxic pulmonary arterial remodelling and PH with primary focus on the endothelin-1, nitric oxide, cyclooxygenase and adenine nucleotide pathways. In summary, endothelin-1 and thromboxane A₂ may enhance, whereas nitric oxide and prostacyclin may moderate, HPV as well as hypoxic pulmonary arterial remodelling and PH. The production of prostacyclin seems to be coupled primarily to cyclooxygenase-1 in acute hypoxia, but to cyclooxygenase-2 in chronic hypoxia. The potential role of adenine nucleotides in modulating HPV is unclear, but warrants further study. Additional modulators of the pulmonary vascular responses to hypoxia may include angiotensin II, histamine, serotonin/5-hydroxytryptamine, leukotrienes and epoxyeicosatrienoic acids. Drugs targeting these pathways may reduce acute and/or chronic hypoxic PH. Endothelin receptor antagonists and phosphodiesterase-5 inhibitors may additionally improve exercise capacity in hypoxia. Importantly, the modulation of the pulmonary vascular responses to hypoxia varies between species and individuals, with hypoxic duration and age. The review also define how drugs targeting the endothelin-1, nitric oxide, cyclooxygenase and adenine nucleotide pathways may improve pulmonary haemodynamics, but also impair pulmonary gas exchange by interference with HPV in chronic lung diseases.

Soluble Guanylate Cyclase Stimulators and Activators: Novel Therapies for Pulmonary Vascular Disease or a Different Method of Increasing cGMP?

Pulmonary arterial hypertension (PAH) is a progressively worsening disorder characterized by increased pulmonary vascular resistance leading to increased afterload, right ventricular hypertrophy, and ultimately right heart failure and death. Current pharmacologic treatments primarily act to reduce pulmonary vascular resistance (PVR) and provide some benefit but do not cure PAH. Canonical vasodilator therapy involving the nitric oxide (NO)-soluble guanylate cyclase (sGC)-cGMP pathway has demonstrated efficacy, but in pathologic states, endothelial dysfunction within the pulmonary vasculature leads to the reduced synthesis and bioavailability of NO. Acting downstream of NO, sGC stimulators and activators restore the endogenous functions of NO and exploit the positive effects of sGC stimulation on various organ systems, including the heart. Riociguat (BAY 63-2521) is the first agent in a class of sGC stimulators to receive FDA approval for the treatment of PAH and chronic thromboembolic hypertension (CTEPH). Riociguat has demonstrated significant benefit as assessed by 6MWD, PVR, N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, time to clinical worsening, World Health Organization (WHO) functional class, and other quality of life measures in clinical trials as a monotherapy and in combination with endothelin receptor antagonists or non-intravenous prostanoids. Riociguat is the first FDA-approved treatment option for inoperable or persistent CTEPH and adds a new effective drug to available treatment options for pulmonary hypertension (PH). The question of whether riociguat is superior to other available treatment options is unanswered at the present time and requires further study.

BAY 41-2272 activates host defence against local and disseminated Candida albicans infections

In our previous study, we have found that 5-cyclopropyl-2-[1-(2-fluoro-benzyl)-1H-pyrazolo[3,4-b]pyridine-3-yl]-pyrimidin-4-ylamine (BAY 41-2272), a guanylate cyclase agonist, activates human monocytes and the THP-1 cell line to produce the superoxide anion, increasing in vitro microbicidal activity, suggesting that this drug can be used to modulate immune functioning in primary immunodeficiency patients. In the present work, we investigated the potential of the in vivo administration of BAY 41-2272 for the treatment of Candida albicans and Staphylococcus aureus infections introduced via intraperitoneal and subcutaneous inoculation. We found that intraperitoneal treatment with BAY 41-2272 markedly increased macrophage-dependent cell influx to the peritoneum in addition to macrophage functions, such as spreading, zymosan particle phagocytosis and nitric oxide and phorbol myristate acetate-stimulated hydrogen peroxide production. Treatment with BAY 41-2272 was highly effective in reducing the death rate due to intraperitoneal inoculation of C. albicans, but not S. aureus. However, we found that in vitro stimulation of peritoneal macrophages with BAY 41-2272 markedly increased microbicidal activities against both pathogens. Our results show that the prevention of death by the treatment of C. albicans-infected mice with BAY 41-2272 might occur primarily by the modulation of the host immune response through macrophage activation.

Enhanced endothelium-dependent relaxation of rat pulmonary artery following β-adrenergic overstimulation: involvement of the NO/cGMP/VASP pathway

AIMS

The aim of this study was to investigate whether β-adrenoceptor (β-AR) overstimulation induced by in vivo treatment with isoproterenol (ISO) alters vascular reactivity and nitric oxide (NO) production and signaling in pulmonary arteries.

MAIN METHODS

Vehicle or ISO (0.3mgkg(-1)day(-1)) was administered daily to male Wistar rats. After 7days, the jugular vein was cannulated to assess right ventricular (RV) systolic pressure (SP) and end diastolic pressure (EDP). The extralobar pulmonary arteries were isolated to evaluate the relaxation responses, protein expression (Western blot), NO production (diaminofluorescein-2 fluorescence), and cyclic guanosine 3',5'-monophosphate (cGMP) levels (enzyme immunoassay kit).

KEY FINDINGS

ISO treatment induced RV hypertrophy; however, no differences in RV-SP and EDP were observed. The pulmonary arteries from the ISO-treated group showed enhanced relaxation to acetylcholine that was abolished by the NO synthase (NOS) inhibitor N(ω)-nitro-l-arginine methyl ester (l-NAME); whereas relaxation elicited by sodium nitroprusside, ISO, metaproterenol, mirabegron, or KCl was not affected by ISO treatment. ISO-treated rats displayed enhanced endothelial NOS (eNOS) and vasodilator-stimulated phosphoprotein (VASP) expression in the pulmonary arteries, while phosphodiesterase-5 protein expression decreased. ISO treatment increased NO and cGMP levels and did not induce eNOS uncoupling.

SIGNIFICANCE

The present data indicate that β-AR overactivation enhances the endothelium-dependent relaxation of pulmonary arteries. This effect was linked to an increase in eNOS-derived NO production, cGMP formation and VASP content and to a decrease in phosphodiesterase-5 expression. Therefore, elevated NO bioactivity through cGMP/VASP signaling could represent a protective mechanism of β-AR overactivation on pulmonary circulation.

The role of cGMP in the physiological and molecular responses of the right ventricle to pressure overload

Pulmonary arterial hypertension (PAH) is a progressive disease that is associated with a poor prognosis and results in right heart dysfunction. While pulmonary vascular disease is the obvious primary pathological focus, right ventricular hypertrophy (RVH) and right ventricular (RV) dysfunction are major determinants of prognosis in PAH. Our knowledge about the molecular physiology and pathophysiology of RV hypertrophy and failure in response to pressure overload is still limited, and most data are derived from left heart research. However, the molecular mechanisms of left ventricular remodelling cannot be generalized to the RV, because the right and left ventricles differ greatly in their size, shape, architecture and function. Despite the recent advances in diagnosis and treatment of PAH, little is known about the molecular and cellular mechanisms that underlie the transition from compensatory to maladaptive RV remodelling. The cGMP-phosphodiesterase 5 (PDE5) pathway is one of the extensively studied pathways in PAH, but our knowledge about cGMP-PDE5 signalling in RV pathophysiology is still limited. For this purpose, there is need for animal models that can represent changes in the RV that closely mimic the human situation. The availability of an animal model of pressure-overload-induced RVH (e.g. pulmonary artery banding model) provides us with a valuable tool to understand the differences between adaptive and maladaptive RVH and to explore the direct effects of current PAH therapy on the heart. In this report, we discuss myocardial regulatory effects of cGMP-PDE5 signalling in preclinical models of RV pressure overload for understanding the physiological/pathophysiological mechanisms involved in maladaptive RVH.

The effects of cyclic guanylate cyclase stimulation on right ventricular hypertrophy and failure alone and in combination with phosphodiesterase-5 inhibition

BACKGROUND

We investigated if soluble guanylate cyclase stimulation either alone or in combination with phosphodiesterase-5 (PDE5) inhibition could prevent pressure overload-induced right ventricular (RV) hypertrophy and failure.

METHODS

The soluble guanylate cyclase stimulator BAY 41-2272 (BAY, 10 mg · kg⁻¹ · d⁻¹) either alone or in combination (BAY + SIL) with a PDE5 inhibitor sildenafil (SIL, 100 mg · kg⁻¹ · d⁻¹) was examined for prevention of RV hypertrophy and failure in Wistar rats (n = 73) operated by pulmonary trunk banding.

RESULTS

All treatments failed to inhibit the development of RV hypertrophy and failure. In the BAY and BAY + SIL groups, there was an increased mortality. Mean arterial blood pressure was lowered and cardiac output increased in the BAY + SIL group. Systolic RV pressure was increased in the BAY and BAY + SIL groups possibly because of an inotropic response and/or increased venous return.

CONCLUSIONS

Stimulation of soluble guanylate cyclase by BAY 41-2272 alone or in combination with sildenafil failed to prevent the development of RV hypertrophy and failure in rats subjected to pulmonary trunk banding. An increased mortality was observed in animals treated by BAY 41-2272 alone and in combination with sildenafil.

The soluble guanylyl cyclase activator bay 58-2667 selectively limits cardiomyocyte hypertrophy

BACKGROUND

Although evidence now suggests cGMP is a negative regulator of cardiac hypertrophy, the direct consequences of the soluble guanylyl cyclase (sGC) activator BAY 58-2667 on cardiac remodeling, independent of changes in hemodynamic load, has not been investigated. In the present study, we tested the hypothesis that the NO(•)-independent sGC activator BAY 58-2667 inhibits cardiomyocyte hypertrophy in vitro. Concomitant impact of BAY 58-2667 on cardiac fibroblast proliferation, and insights into potential mechanisms of action, were also sought. Results were compared to the sGC stimulator BAY 41-2272.

METHODS

Neonatal rat cardiomyocytes were incubated with endothelin-1 (ET(1), 60nmol/L) in the presence and absence of BAY 41-2272 and BAY 58-2667 (0.01-0.3 µmol/L). Hypertrophic responses and its triggers, as well as cGMP signaling, were determined. The impact of both sGC ligands on basal and stimulated cardiac fibroblast proliferation in vitro was also determined.

RESULTS

We now demonstrate that BAY 58-2667 (0.01-0.3 µmol/L) elicited concentration-dependent antihypertrophic actions, inhibiting ET(1)-mediated increases in cardiomyocyte 2D area and de novo protein synthesis, as well as suppressing ET(1)-induced cardiomyocyte superoxide generation. This was accompanied by potent increases in cardiomyocyte cGMP accumulation and activity of its downstream signal, vasodilator-stimulated phosphoprotein (VASP), without elevating cardiomyocyte cAMP. In contrast, submicromolar concentrations of BAY 58-2667 had no effect on basal or stimulated cardiac fibroblast proliferation. Indeed, only at concentrations ≥10 µmol/L was inhibition of cardiac fibrosis seen in vitro. The effects of BAY 58-2667 in both cell types were mimicked by BAY 41-2272.

CONCLUSIONS

Our results demonstrate that BAY 58-2667 elicits protective, cardiomyocyte-selective effects in vitro. These actions are associated with sGC activation and are evident in the absence of confounding hemodynamic factors, at low (submicromolar) concentrations. Thus this distinctive sGC ligand may potentially represent an alternative therapeutic approach for limiting myocardial hypertrophy.

Phosphodiesterases Regulate BAY 41-2272-Induced VASP Phosphorylation in Vascular Smooth Muscle Cells

BAY 41-2272 (BAY), a stimulator of soluble guanylyl cyclase, increases cyclic nucleotides and inhibits proliferation of vascular smooth muscle cells (VSMCs). In this study, we elucidated mechanisms of action of BAY in its regulation of vasodilator-stimulated phosphoprotein (VASP) with an emphasis on VSMC phosphodiesterases (PDEs). BAY alone increased phosphorylation of VASP(Ser239) and VASP(Ser157), respective indicators of PKG and PKA signaling. IBMX, a non-selective inhibitor of PDEs, had no effect on BAY-induced phosphorylation at VASP(Ser239) but inhibited phosphorylation at VASP(Ser157). Selective inhibitors of PDE3 or PDE4 attenuated BAY-mediated increases at VASP(Ser239) and VASP(Ser157), whereas PDE5 inhibition potentiated BAY-mediated increases only at VASP(Ser157). In comparison, 8Br-cGMP increased phosphorylation at VASP(Ser239) and VASP(Ser157) which were not affected by selective PDE inhibitors. In the presence of 8Br-cAMP, inhibition of either PDE4 or PDE5 decreased VASP(Ser239) phosphorylation and inhibition of PDE3 increased phosphorylation at VASP(Ser239), while inhibition of PDE3 or PDE4 increased and PDE5 inhibition had no effect on VASP(Ser157) phosphorylation. These findings demonstrate that BAY operates via cAMP and cGMP along with regulation by PDEs to phosphorylate VASP in VSMCs and that the mechanism of action of BAY in VSMCs is different from that of direct cyclic nucleotide analogs with respect to VASP phosphorylation and the involvement of PDEs. Given a role for VASP as a critical cytoskeletal protein, these findings provide evidence for BAY as a regulator of VSMC growth and a potential therapeutic agent against vasculoproliferative disorders.

Sildenafil treatment attenuates lung and kidney injury due to overproduction of oxidant activity in a rat model of sepsis: a biochemical and histopathological study

Sepsis is a systemic inflammatory response to infection and a major cause of morbidity and mortality. Sildenafil (SLD) is a selective and potent inhibitor of cyclic guanosine monophosphate (cGMP)-specific phosphodiesterase PDE5. We aimed to investigate the protective effects of sildenafil on caecal ligation and puncture (CLP)-induced sepsis in rats. Four groups of rats were used, each composed of 10 rats: (i) 10 mg/kg SLD-treated CLP group; (ii) 20 mg/kg SLD-treated CLP group; (iii) CLP group; and (iv) sham-operated control group. A CLP polymicrobial sepsis model was applied to the rats. All groups were killed 16 h later, and lung, kidney and blood samples were analysed histopathologically and biochemically. Sildenafil increased glutathione (GSH) and decreased the activation of myeloperoxidase (MPO) and of lipid peroxidase (LPO) and levels of superoxide dismutase (SOD) in the septic rats. We observed a significant decrease in LPO and MPO and a decrease in SOD activity in the sildenafil-treated CLP rats compared with the sham group. In addition, 20 mg/kg sildenafil treatment in the sham-operated rats improved the biochemical status of lungs and kidneys. Histopathological analysis revealed significant differences in inflammation scores between the sepsis group and the other groups, except the CLP + sildenafil 10 mg/kg group. The CLP + sildenafil 20 mg/kg group had the lowest inflammation score. Sildenafil treatment decreased the serum tumour necrosis factor (TNF)-α level when compared to the CLP group. Our results indicate that sildenafil is a highly protective agent in preventing lung and kidney damage caused by CLP-induced sepsis via maintenance of the oxidant-anti-oxidant status and decrease in the level of TNF-α.

The soluble guanylate cyclase stimulator BAY 41-2272 inhibits vascular smooth muscle growth through the cAMP-dependent protein kinase and cGMP-dependent protein kinase pathways

Vascular smooth muscle (VSM) proliferation and migration are key components in vessel remodeling. Cyclic nucleotide signaling is protective and has long-served as a therapeutic target against undesired VSM growth. The present work analyzed the effects of the soluble guanylate cyclase (sGC) stimulator 3-(4-amino-5-cyclopropylpyrimidine-2-yl)-1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridine [BAY 41-2272 (BAY)] on VSM growth, and we hypothesize that BAY has the capacity to reduce proliferation and migration via cyclic nucleotide-driven kinase signaling. Perivascular BAY postballoon injury reduced neointimal growth by ∼ 40% compared with vehicle controls after 2 weeks. In VSM cells, BAY (10 μM) reduced proliferation by ∼ 40% after 72 h and migration by ∼ 40% after 6 h and ∼ 60% after 18 h without deleterious effects on cell viability. cGMP content peaked (248 ×) 20 min after BAY treatment and remained elevated (140 ×) through 60 min; however, BAY did not affect cAMP levels compared with controls. Conventional and In-Cell Western analyses showed increases in vasodilator-stimulated phosphoprotein (VASP) phosphorylation (pVASP) at serines 239 (3 ×) and 157 (2 ×), respective markers of cGMP- and cAMP-directed protein kinases (PKG and PKA, respectively). The PKG inhibitor YGRKKRRQRRRPPLRKKKKKH peptide (DT-2) completely reversed BAY-mediated increases in pVASPSer(239) and BAY-mediated inhibition of migration. In comparison, the PKA inhibitor peptide PKI further potentiated BAY-stimulated pVASPSer(157) and pVASPSer(239) and partially reversed the antiproliferative effects of BAY. This is the first report demonstrating the effectiveness of BAY in reducing neointimal growth with direct evidence for PKG-specific antimigratory and PKA-specific antiproliferative mechanisms. Conclusively, the sGC stimulator BAY reduces VSM growth through cGMP-dependent PKG and PKA processes, providing support for continued evaluation of its clinical utility.