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The soluble guanylate cyclase activator BAY 58-2667 protects against morbidity and mortality in endotoxic shock by recoupling organ systems.

Vandendriessche B, Rogge E, Goossens V, Vandenabeele P, Stasch JP, Brouckaert P, Cauwels A - PLoS ONE (2013)

Bottom Line: Protection was associated with reduced hypothermia, circulating IL-6 levels, cardiomyocyte apoptosis, and mortality.In contrast to BAY 58-2667, the sGC stimulator BAY 41-2272 and the phosphodiesterase 5 inhibitor Sildenafil did not have any beneficial effect on survival, emphasizing the importance of the selectivity of BAY 58-2667 for diseased vessels and tissues.In conclusion, our results demonstrate the pivotal role of the NO/sGC axis in endotoxic shock.

View Article: PubMed Central - PubMed

Affiliation: Department for Molecular Biomedical Research, VIB, Ghent, Belgium ; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.

ABSTRACT
Sepsis and septic shock are associated with high mortality rates and the majority of sepsis patients die due to complications of multiple organ failure (MOF). The cyclic GMP (cGMP) producing enzyme soluble guanylate cyclase (sGC) is crucially involved in the regulation of (micro)vascular homeostasis, cardiac function and, consequently, organ function. However, it can become inactivated when exposed to reactive oxygen species (ROS). The resulting heme-free sGC can be reactivated by the heme- and nitric oxide (NO)-independent sGC activator BAY 58-2667 (Cinaciguat). We report that late (+8 h) post-treatment with BAY 58-2667 in a mouse model can protect against lethal endotoxic shock. Protection was associated with reduced hypothermia, circulating IL-6 levels, cardiomyocyte apoptosis, and mortality. In contrast to BAY 58-2667, the sGC stimulator BAY 41-2272 and the phosphodiesterase 5 inhibitor Sildenafil did not have any beneficial effect on survival, emphasizing the importance of the selectivity of BAY 58-2667 for diseased vessels and tissues. Hemodynamic parameters (blood pressure and heart rate) were decreased, and linear and nonlinear indices of blood pressure variability, reflective for (un)coupling of the communication between the autonomic nervous system and the heart, were improved after late protective treatment with BAY 58-2667. In conclusion, our results demonstrate the pivotal role of the NO/sGC axis in endotoxic shock. Stabilization of sGC function with BAY 58-2667 can prevent mortality when given in the correct treatment window, which probably depends on the dynamics of the heme-free sGC pool, in turn influenced by oxidative stress. We speculate that, considering the central role of sGC signaling in many pathways required for maintenance of (micro)circulatory homeostasis, BAY 58-2667 supports organ function by recoupling inter-organ communication pathways.

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Schematic overview of drug interactions with the NO/sGC/cGMP pathway.NO produced by NOS activates sGC, resulting in the production of cGMP, and subsequent relaxation of VSMCs and inhibition of platelet aggregation and leukocyte adhesion, among others. In turn, cGMP is broken down to GMP by PDE5, which can be inhibited by Sildenafil. ROS can interact at various levels with this pathway, including facilitating the oxidation of the iron in the heme-prosthetic group of sGC. The resulting heme-free sGC (apoGC) is no longer functional and a target for rapid ubiquitin-mediated proteolytic degradation. However, BAY 58-2667 can bind heme-free sGC and reactivate cGMP production independent of NO. BAY 41-2272, on the other hand, can stimulate the activity of functional (reduced-heme) sGC synergistically with NO. Nitrite, a hypoxia selective NO donor, can also be used to stimulate this pathway selectively. No cell specific effects for the compounds or enzymes are assumed, they are shown as such for simplicity only. Arrows indicate binding, interaction or induction; bold arrows indicates increased production; dashed lines indicate an inhibitory effect; bold/underlined text indicates NO/cGMP-mediated effects; ‘apoGC’ = heme-free sGC. Figure was produced using Servier Medical Art.
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pone-0072155-g001: Schematic overview of drug interactions with the NO/sGC/cGMP pathway.NO produced by NOS activates sGC, resulting in the production of cGMP, and subsequent relaxation of VSMCs and inhibition of platelet aggregation and leukocyte adhesion, among others. In turn, cGMP is broken down to GMP by PDE5, which can be inhibited by Sildenafil. ROS can interact at various levels with this pathway, including facilitating the oxidation of the iron in the heme-prosthetic group of sGC. The resulting heme-free sGC (apoGC) is no longer functional and a target for rapid ubiquitin-mediated proteolytic degradation. However, BAY 58-2667 can bind heme-free sGC and reactivate cGMP production independent of NO. BAY 41-2272, on the other hand, can stimulate the activity of functional (reduced-heme) sGC synergistically with NO. Nitrite, a hypoxia selective NO donor, can also be used to stimulate this pathway selectively. No cell specific effects for the compounds or enzymes are assumed, they are shown as such for simplicity only. Arrows indicate binding, interaction or induction; bold arrows indicates increased production; dashed lines indicate an inhibitory effect; bold/underlined text indicates NO/cGMP-mediated effects; ‘apoGC’ = heme-free sGC. Figure was produced using Servier Medical Art.

Mentions: Soluble guanylate cyclase (sGC) is a heterodimeric enzyme, primarily found in the α1β1 and, to a lesser extent, the α2β1 isoform. Upon binding of NO to the heme prosthetic group of the enzyme, cyclic GMP (cGMP) production is increased about 200-fold. cGMP, in turn, interacts with cGMP-activated protein kinases, cyclic nucleotide-gated channels and phosphodiesterases (PDEs), and is involved in the regulation of various physiological functions, including vasodilation, platelet aggregation, and neurotransmission [9], [10]. Previously, we showed that the hypoxia selective NO donor nitrite (NO2−) can protect against toxicity in shock via sGC-dependent signaling, which may include hypoxic vasodilation necessary to maintain microcirculation and organ function, and cardioprotection [11]. Furthermore, a study in sGCα1 knockout mice showed that cGMP generated by sGCα1β1 protects against cardiac dysfunction and mortality in murine inflammatory shock models [12]. In light of these findings, we decided to test the heme- and hence NO-independent sGC activator BAY 58-2667 (Cinaciguat) and the heme-dependent sGC stimulator BAY 41-2272 in a murine model of inflammatory shock (Fig. 1). ROS interact at various levels with the NO/sGC/cGMP pathway: at the level of sGC, they can oxidize the ferrous iron (Fe2+) in the heme prosthetic group, which can lead to release of the heme, thereby rendering the enzyme inactive and prone to ubiquitin-mediated proteolytic degradation [13]. BAY 58-2667 competes for the heme-binding motif of heme-free sGC (also known as apo-sGC), and as such protects the enzyme from proteolytic breakdown and reactivates cGMP production in the absence of NO [14]. Consequently, BAY 58-2667 is assumed to be specific for tissues that are suffering from hypoxia, cytopathic hypoxia and/or oxidative stress, and is thought to be most effective when a considerable pool of heme-free sGC is present, which can occur both in the case of chronic low-level inflammation or acute (systemic) inflammation [15], [16]. BAY 41-2272, on the other hand, will act synergistically with NO to stimulate the activity of functional (reduced-heme) sGC [17]. Documented effects of treatment with BAY 58-2667 and BAY 41-2272 in various disease models include: reducing preload and afterload, increasing cardiac output, inducing pulmonary vasodilation, reducing cardiac hypertrophy, inhibiting platelet aggregation, increasing renal blood flow and glomerular filtration rate, and lowering systemic BP [18], [19]. In addition, Sildenafil (Viagra™), a phosphodiesterase-5 (PDE5) inhibitor that inhibits breakdown of cGMP to GMP, was used as a control drug [20].


The soluble guanylate cyclase activator BAY 58-2667 protects against morbidity and mortality in endotoxic shock by recoupling organ systems.

Vandendriessche B, Rogge E, Goossens V, Vandenabeele P, Stasch JP, Brouckaert P, Cauwels A - PLoS ONE (2013)

Schematic overview of drug interactions with the NO/sGC/cGMP pathway.NO produced by NOS activates sGC, resulting in the production of cGMP, and subsequent relaxation of VSMCs and inhibition of platelet aggregation and leukocyte adhesion, among others. In turn, cGMP is broken down to GMP by PDE5, which can be inhibited by Sildenafil. ROS can interact at various levels with this pathway, including facilitating the oxidation of the iron in the heme-prosthetic group of sGC. The resulting heme-free sGC (apoGC) is no longer functional and a target for rapid ubiquitin-mediated proteolytic degradation. However, BAY 58-2667 can bind heme-free sGC and reactivate cGMP production independent of NO. BAY 41-2272, on the other hand, can stimulate the activity of functional (reduced-heme) sGC synergistically with NO. Nitrite, a hypoxia selective NO donor, can also be used to stimulate this pathway selectively. No cell specific effects for the compounds or enzymes are assumed, they are shown as such for simplicity only. Arrows indicate binding, interaction or induction; bold arrows indicates increased production; dashed lines indicate an inhibitory effect; bold/underlined text indicates NO/cGMP-mediated effects; ‘apoGC’ = heme-free sGC. Figure was produced using Servier Medical Art.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3756074&req=5

pone-0072155-g001: Schematic overview of drug interactions with the NO/sGC/cGMP pathway.NO produced by NOS activates sGC, resulting in the production of cGMP, and subsequent relaxation of VSMCs and inhibition of platelet aggregation and leukocyte adhesion, among others. In turn, cGMP is broken down to GMP by PDE5, which can be inhibited by Sildenafil. ROS can interact at various levels with this pathway, including facilitating the oxidation of the iron in the heme-prosthetic group of sGC. The resulting heme-free sGC (apoGC) is no longer functional and a target for rapid ubiquitin-mediated proteolytic degradation. However, BAY 58-2667 can bind heme-free sGC and reactivate cGMP production independent of NO. BAY 41-2272, on the other hand, can stimulate the activity of functional (reduced-heme) sGC synergistically with NO. Nitrite, a hypoxia selective NO donor, can also be used to stimulate this pathway selectively. No cell specific effects for the compounds or enzymes are assumed, they are shown as such for simplicity only. Arrows indicate binding, interaction or induction; bold arrows indicates increased production; dashed lines indicate an inhibitory effect; bold/underlined text indicates NO/cGMP-mediated effects; ‘apoGC’ = heme-free sGC. Figure was produced using Servier Medical Art.
Mentions: Soluble guanylate cyclase (sGC) is a heterodimeric enzyme, primarily found in the α1β1 and, to a lesser extent, the α2β1 isoform. Upon binding of NO to the heme prosthetic group of the enzyme, cyclic GMP (cGMP) production is increased about 200-fold. cGMP, in turn, interacts with cGMP-activated protein kinases, cyclic nucleotide-gated channels and phosphodiesterases (PDEs), and is involved in the regulation of various physiological functions, including vasodilation, platelet aggregation, and neurotransmission [9], [10]. Previously, we showed that the hypoxia selective NO donor nitrite (NO2−) can protect against toxicity in shock via sGC-dependent signaling, which may include hypoxic vasodilation necessary to maintain microcirculation and organ function, and cardioprotection [11]. Furthermore, a study in sGCα1 knockout mice showed that cGMP generated by sGCα1β1 protects against cardiac dysfunction and mortality in murine inflammatory shock models [12]. In light of these findings, we decided to test the heme- and hence NO-independent sGC activator BAY 58-2667 (Cinaciguat) and the heme-dependent sGC stimulator BAY 41-2272 in a murine model of inflammatory shock (Fig. 1). ROS interact at various levels with the NO/sGC/cGMP pathway: at the level of sGC, they can oxidize the ferrous iron (Fe2+) in the heme prosthetic group, which can lead to release of the heme, thereby rendering the enzyme inactive and prone to ubiquitin-mediated proteolytic degradation [13]. BAY 58-2667 competes for the heme-binding motif of heme-free sGC (also known as apo-sGC), and as such protects the enzyme from proteolytic breakdown and reactivates cGMP production in the absence of NO [14]. Consequently, BAY 58-2667 is assumed to be specific for tissues that are suffering from hypoxia, cytopathic hypoxia and/or oxidative stress, and is thought to be most effective when a considerable pool of heme-free sGC is present, which can occur both in the case of chronic low-level inflammation or acute (systemic) inflammation [15], [16]. BAY 41-2272, on the other hand, will act synergistically with NO to stimulate the activity of functional (reduced-heme) sGC [17]. Documented effects of treatment with BAY 58-2667 and BAY 41-2272 in various disease models include: reducing preload and afterload, increasing cardiac output, inducing pulmonary vasodilation, reducing cardiac hypertrophy, inhibiting platelet aggregation, increasing renal blood flow and glomerular filtration rate, and lowering systemic BP [18], [19]. In addition, Sildenafil (Viagra™), a phosphodiesterase-5 (PDE5) inhibitor that inhibits breakdown of cGMP to GMP, was used as a control drug [20].

Bottom Line: Protection was associated with reduced hypothermia, circulating IL-6 levels, cardiomyocyte apoptosis, and mortality.In contrast to BAY 58-2667, the sGC stimulator BAY 41-2272 and the phosphodiesterase 5 inhibitor Sildenafil did not have any beneficial effect on survival, emphasizing the importance of the selectivity of BAY 58-2667 for diseased vessels and tissues.In conclusion, our results demonstrate the pivotal role of the NO/sGC axis in endotoxic shock.

View Article: PubMed Central - PubMed

Affiliation: Department for Molecular Biomedical Research, VIB, Ghent, Belgium ; Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium.

ABSTRACT
Sepsis and septic shock are associated with high mortality rates and the majority of sepsis patients die due to complications of multiple organ failure (MOF). The cyclic GMP (cGMP) producing enzyme soluble guanylate cyclase (sGC) is crucially involved in the regulation of (micro)vascular homeostasis, cardiac function and, consequently, organ function. However, it can become inactivated when exposed to reactive oxygen species (ROS). The resulting heme-free sGC can be reactivated by the heme- and nitric oxide (NO)-independent sGC activator BAY 58-2667 (Cinaciguat). We report that late (+8 h) post-treatment with BAY 58-2667 in a mouse model can protect against lethal endotoxic shock. Protection was associated with reduced hypothermia, circulating IL-6 levels, cardiomyocyte apoptosis, and mortality. In contrast to BAY 58-2667, the sGC stimulator BAY 41-2272 and the phosphodiesterase 5 inhibitor Sildenafil did not have any beneficial effect on survival, emphasizing the importance of the selectivity of BAY 58-2667 for diseased vessels and tissues. Hemodynamic parameters (blood pressure and heart rate) were decreased, and linear and nonlinear indices of blood pressure variability, reflective for (un)coupling of the communication between the autonomic nervous system and the heart, were improved after late protective treatment with BAY 58-2667. In conclusion, our results demonstrate the pivotal role of the NO/sGC axis in endotoxic shock. Stabilization of sGC function with BAY 58-2667 can prevent mortality when given in the correct treatment window, which probably depends on the dynamics of the heme-free sGC pool, in turn influenced by oxidative stress. We speculate that, considering the central role of sGC signaling in many pathways required for maintenance of (micro)circulatory homeostasis, BAY 58-2667 supports organ function by recoupling inter-organ communication pathways.

Show MeSH
Related in: MedlinePlus