Effect Of C-type Natriuretic Peptide Research Articles

Exploring the Therapeutic Potential of C-Type Natriuretic Peptide for Preeclampsia.

Preeclampsia is a serious condition of pregnancy, complicated by aberrant maternal vascular dysfunction. CNP (C-type natriuretic peptide) contributes to vascular homeostasis, acting through NPR-B (natriuretic peptide receptor-B) and NPR-C (natriuretic peptide receptor-C). CNP mitigates vascular dysfunction of arteries in nonpregnant cohorts; this study investigates whether CNP can dilate maternal arteries in ex vivo preeclampsia models. Human omental arteries were dissected from fat biopsies collected during cesarean section. CNP, NPR-B, and NPR-C mRNA expression was assessed in arteries collected from pregnancies complicated by preeclampsia (n=6) and normotensive controls (n=11). Using wire myography, we investigated the effects of CNP on dilation of arteries from normotensive pregnancies. Arteries were preconstricted with either serum from patients with preeclampsia (n=6) or recombinant ET-1 (endothelin-1; vasoconstrictor elevated in preeclampsia; n=6) to model vasoconstriction associated with preeclampsia. Preconstricted arteries were treated with recombinant CNP (0.001-100 µmol/L) or vehicle and vascular relaxation assessed. In further studies, arteries were preincubated with NPR-B (5 µmol/L) and NPR-C (10 µmol/L) antagonists before serum-induced constriction (n=4-5) to explore mechanistic signaling. CNP, NPR-B, and NPR-C mRNAs were not differentially expressed in omental arteries from preeclamptic pregnancies. CNP potently stimulated maternal artery vasorelaxation in our model of preeclampsia (using preeclamptic serum). Its vasodilatory actions were driven through the activation of NPR-B predominantly; antagonism of this receptor alone dampened CNP vasorelaxation. Interestingly, CNP did not reduce ET-1-driven omental artery constriction. Collectively, these data suggest that enhancing CNP signaling through NPR-B offers a potential therapeutic strategy to reduce systemic vascular constriction in preeclampsia.

Pre-IVM with C-type natriuretic peptide promotes mitochondrial biogenesis of bovine oocytes via activation of CREB

The aim of this study was to evaluate the effects of C-type natriuretic peptide (CNP) treatment prior to in vitro maturation (IVM) on mitochondria biogenesis in bovine oocyte matured in vitro and explore the related causes. The results showed that treatment with CNP before IVM significantly improved mitochondrial content, elevated the expression of genes related to mitochondria biogenesis, and increased the protein levels of phosphorylation of cAMP-response element binding protein (p-CREB) in bovine oocytes following IVM. However, further studies revealed that treatment with CNP before IVM could not increased the protein levels of p-CREB in bovine oocytes when natriuretic peptide receptor 2 activities was inhibited using the relative specific inhibitor Gö6976. In addition, treatment with CNP before IVM could not improved mitochondrial content or elevated the expression of genes related to mitochondria biogenesis in bovine oocytes when CREB activities was abolished using the specific inhibitor 666–15. In summary, these results provide evidence that treatment of bovine oocytes with CNP before IVM promotes mitochondrial biogenesis in vitro, possibly by activating CREB.

C-type natriuretic peptide treatment before in vitro maturation enhances maturation of yak oocytes and developmental competence of their crossbred embryos

ABSTRACT The effects of C-type natriuretic peptide (CNP) pre-treatment on the in vitro maturation (IVM) and developmental competence of yak (Bos grunniens) oocytes were evaluated. The results showed that 100 nM CNP could effectively maintain meiotic arrest of yak oocytes in vitro within 6 h. Yak oocytes matured in two-step IVM (pre-IVM with 100 nM CNP for 6 h followed by conventional IVM for 28 h) yielded a significantly (P < .05) increased cleavage rate, blastocyst rate after in vitro fertilization with cattle spermatozoa compared to the conventional one-step IVM method. The density of transzonal projections (TZPs) decreased after 6 h standard IVM (P < .05), whereas, COCs pre-IVM with 100 nM CNP for 6 h maintained the same density of TZPs compared to the fresh COCs. This pre-IVM resulted in lesser reactive oxygen species level (P < .05). Two-step IVM resulted in the increased glutathione levels, mRNA expression levels of BCL2, BMP15, and GDF9 (P < .05) in oocytes. In conclusion, these results indicate that CNP treatment (100 nM, 6 h) before IVM could enhance the maturation of yak oocytes and developmental competence of their crossbred embryos. This may have important applications in in vitro production of yak crossbred embryos.

Efficiency of C-type natriuretic peptide on improvement of Iraqi local ram's epididymal sperms.

Fertility plays a great role in animal reproduction since high-quality semen improves sheep industry reproduction. The current worldwide data revealed the close relation of C-type natriuretic peptide (CNP) to the reproductive function of rams. Evaluation of the effect of CNP on cooled sperms using traditional and molecular assays. Totally, of 20 testicular samples were collected, processed to obtain the semen samples, and divided into two parts; one was treated with a suitable dose of CNP, and the other served as a control. Sperm samples of both groups were cooled for 3 days and tested at 0, 24, 48, and 72 hours. The findings revealed that the suitable dose of CNP-treated sperms was 0.01 × 10-13. Values of individual motility, live sperms, and sperm concentration were reduced significantly in CNP-24h, CNP-48h, and CNP-72h when compared to control; however, abnormal sperms were increased in both control and CNP groups at 24, 48, and 72 hours when compared to values of 0 hour. Concerning turbidmetric analysis, a significant reduction in values of lag time was observed in CNP when compared to control at all times of cooling intervals. In both CNP and control groups, motility index was decreased at 24, 48, and 72 hours when compared to 0 hour. For velocity, significant increases were shown in CNP compared with control at all cooling intervals. However, values of both groups were increased significantly at 24, 48, and 72 hours times when compared to 0 hour. Fraction of rapidly moving sperm of CNP was elevated at 0 hour and decreased at 24, 48, and 72 hours when compared to control. Expression of the hNPR-B gene was reduced gradually in sperms of CNP and control groups at times of cooling intervals. To the best of our knowledge, this first Iraqi study targets the effect of CNP on epididymal sperms of rams. However, changes that occur after excessive CNP exposure remain unclear, and the toxicological profile of CNP requires furthermore supplements.

C-type natriuretic peptide improves maternally aged oocytes quality by inhibiting excessive PINK1/Parkin-mediated mitophagy.

The overall oocyte quality declines with aging, and this effect is strongly associated with a higher reactive oxygen species (ROS) level and the resultant oxidative damage. C-type natriuretic peptide (CNP) is a well-characterized physiological meiotic inhibitor that has been successfully used to improve immature oocyte quality during in vitro maturation. However, the underlying roles of CNP in maternally aged oocytes have not been reported. Here, we found that the age-related reduction in the serum CNP concentration was highly correlated with decreased oocyte quality. Treatment with exogenous CNP promoted follicle growth and ovulation in aged mice and enhanced meiotic competency and fertilization ability. Interestingly, the cytoplasmic maturation of aged oocytes was thoroughly improved by CNP treatment, as assessed by spindle/chromosome morphology and redistribution of organelles (mitochondria, the endoplasmic reticulum, cortical granules, and the Golgi apparatus). CNP treatment also ameliorated DNA damage and apoptosis caused by ROS accumulation in aged oocytes. Importantly, oocyte RNA-seq revealed that the beneficial effect of CNP on aged oocytes was mediated by restoration of mitochondrial oxidative phosphorylation, eliminating excessive mitophagy. CNP reversed the defective phenotypes in aged oocytes by alleviating oxidative damage and suppressing excessive PINK1/Parkin-mediated mitophagy. Mechanistically, CNP functioned as a cAMP/PKA pathway modulator to decrease PINK1 stability and inhibit Parkin recruitment. In summary, our results demonstrated that CNP supplementation constitutes an alternative therapeutic approach for advanced maternal age-related oocyte deterioration and may improve the overall success rates of clinically assisted reproduction in older women.

C-type natriuretic peptide improves maternally aged oocytes quality by inhibiting excessive PINK1/Parkin-mediated mitophagy

The overall oocyte quality declines with aging, and this effect is strongly associated with a higher reactive oxygen species (ROS) level and the resultant oxidative damage. C-type natriuretic peptide (CNP) is a well-characterized physiological meiotic inhibitor that has been successfully used to improve immature oocyte quality during in vitro maturation. However, the underlying roles of CNP in maternally aged oocytes have not been reported. Here, we found that the age-related reduction in the serum CNP concentration was highly correlated with decreased oocyte quality. Treatment with exogenous CNP promoted follicle growth and ovulation in aged mice and enhanced meiotic competency and fertilization ability. Interestingly, the cytoplasmic maturation of aged oocytes was thoroughly improved by CNP treatment, as assessed by spindle/chromosome morphology and redistribution of organelles (mitochondria, the endoplasmic reticulum, cortical granules, and the Golgi apparatus). CNP treatment also ameliorated DNA damage and apoptosis caused by ROS accumulation in aged oocytes. Importantly, oocyte RNA-seq revealed that the beneficial effect of CNP on aged oocytes was mediated by restoration of mitochondrial oxidative phosphorylation, eliminating excessive mitophagy. CNP reversed the defective phenotypes in aged oocytes by alleviating oxidative damage and suppressing excessive PINK1/Parkin-mediated mitophagy. Mechanistically, CNP functioned as a cAMP/PKA pathway modulator to decrease PINK1 stability and inhibit Parkin recruitment. In summary, our results demonstrated that CNP supplementation constitutes an alternative therapeutic approach for advanced maternal age-related oocyte deterioration and may improve the overall success rates of clinically assisted reproduction in older women.

C-type natriuretic peptide induces inotropic and lusitropic effects in human 3D-engineered cardiac tissue: Implications for the regulation of cardiac function in humans.

The role of C-type natriuretic peptide (CNP) in the regulation of cardiac function in humans remains to be established as previous investigations have been confined to animal model systems. Here, we used well-characterized engineered cardiac tissues (ECTs) generated from human stem cell-derived cardiomyocytes and fibroblasts to study the acute effects of CNP on contractility. Application of CNP elicited a positive inotropic response as evidenced by increases in maximum twitch amplitude, maximum contraction slope and maximum calcium amplitude. This inotropic response was accompanied by a positive lusitropic response as demonstrated by reductions in time from peak contraction to 90% of relaxation and time from peak calcium transient to 90% of decay that paralleled increases in maximum contraction decay slope and maximum calcium decay slope. To establish translatability, CNP-induced changes in contractility were also assessed in rat ex vivo (isolated heart) and in vivo models. Here, the effects on force kinetics observed in ECTs mirrored those observed in both the ex vivo and in vivo model systems, whereas the increase in maximal force generation with CNP application was only detected in ECTs. In conclusion, CNP induces a positive inotropic and lusitropic response in ECTs, thus supporting an important role for CNP in the regulation of human cardiac function. The high degree of translatability between ECTs, ex vivo and in vivo models further supports a regulatory role for CNP and expands the current understanding of the translational value of human ECTs. NEW FINDINGS: What is the central question of this study? What are the acute responses to C-type natriuretic peptide (CNP) in human-engineered cardiac tissues (ECTs) on cardiac function and how well do they translate to matched concentrations in animal ex vivo and in vivo models? What is the main finding and its importance? Acute stimulation of ECTs with CNP induced positive lusitropic and inotropic effects on cardiac contractility, which closely reflected the changes observed in rat ex vivo and in vivo cardiac models. These findings support an important role for CNP in the regulation of human cardiac function and highlight the translational value of ECTs.

C-Type Natriuretic Peptide in Essential Hypertension: Old Ways for a New Time

Multiple mechanisms are involved in essential hypertension. Antihypertensive drugs mainly target increased activity of the sympathetic nervous system, altered production of vasoactive mediators, vascular inflammation, fibrosis, and increased peripheral resistance. C-type natriuretic peptide (CNP) is an endothelium-derived peptide that exerts vascular signaling through two receptors: natriuretic peptide receptor-B (NPR-B) and natriuretic peptide receptor-C (NPR-C). This perspective recapitulates the effects of CNP on the vasculature in relation to essential hypertension. Notably, the risk of hypotension when used as therapy is minimal for the CNP system as compared to its related natriuretic peptides, atrial natriuretic peptide, and B-type natriuretic peptide. As modified CNP is currently being introduced as therapy in congenital growth disorders, we propose that targeting the CNP system either by administering exogenous CNP or altering the endogenous concentrations via inhibition of its degradation may represent an important tool in the pharmacological armory for managing long-term essential hypertension.

Therapeutic effect of C-type natriuretic peptide on persistent pain in a rat knee arthritis model.

Intra-articular injection of C-type natriuretic peptide (CNP) at the acute inflammatory stage suppressed fibrotic changes in the infrapatellar fat pad (IFP), articular cartilage degeneration, and persistent pain in a monoiodoacetic acid (MIA)-induced rat knee arthritis model. In this study, we administered CNP during the inflammation subsiding period to evaluate CNP effectiveness in knees with osteoarthritis (OA) pathology. 20male Wistar rats were randomly divided into two groups. The rats received an intra-articular injection of MIA solution in the right knee to induce inflammation-induced joint degeneration. One group subsequently received an intra-articular CNP injection for six consecutive days from day 8, whereas another group received vehicle solution. Pain avoidance behavior tests and histological analyses were conducted to examine the therapeutic effects of CNP. The incapacitance test indicated that the percent weight on the ipsilateral limb decreased after MIA injection by day 4 and continued to decrease until the end of the experiment in the vehicle group, suggesting persistent pain in the knee. Intra-articular injection of CNP reversed the weight-bearing ratio on day 19. Histological evaluation showed that the CNP group had more residual fat tissue in the IFP and fewer calcitonin gene-related peptide-positive nerve endings compared to the vehicle group. CNP could not reverse articular cartilage degeneration. Intra-articular injection of CNP after the IFP fibrosis onset had no significant effect on OA severity and extent. Nevertheless, CNP might be utilized therapeutically for OA treatment since it can alleviate persistent knee pain and inhibit structural changes in residual fat tissue.

C-Type Natriuretic Peptide Acts as a Microorganism-Activated Regulator of the Skin Commensals Staphylococcus epidermidis and Cutibacterium acnes in Dual-Species Biofilms.

The effect of C-type natriuretic peptide in a concentration closer to the normal level in human blood plasma was studied on the mono-species and dual-species biofilms of the skin commensal bacteria Cutibacterium acnes HL043PA2 and Staphylococcus epidermidis ATCC14990. Despite the marginal effect of the hormone on cutibacteria in mono-species biofilms, the presence of staphylococci in the community resulted in a global shift of the CNP effect, which appeared to increase the competitive properties of C. acnes, its proliferation and the metabolic activity of the community. S. epidermidis was mostly inhibited in the presence of CNP. Both bacteria had a significant impact on the gene expression levels revealed by RNA-seq. CNP did not affect the gene expression levels in mono-species cutibacterial biofilms; however, in the presence of staphylococci, five genes were differentially expressed in the presence of the hormone, including two ribosomal proteins and metal ABC transporter permease. In staphylococci, the Na-translocating system protein MpsB NADH-quinone oxidoreductase subunit L was downregulated in the dual-species biofilms in the presence of CNP, while in mono-species biofilms, two proteins of unknown function were downregulated. Hypothetically, at least one of the CNP mechanisms of action is via the competition for zinc, at least on cutibacteria.

CNP Promotes Antiarrhythmic Effects via Phosphodiesterase 2.

Ventricular arrhythmia and sudden cardiac death are the most common lethal complications after myocardial infarction. Antiarrhythmic pharmacotherapy remains a clinical challenge and novel concepts are highly desired. Here, we focus on the cardioprotective CNP (C-type natriuretic peptide) as a novel antiarrhythmic principle. We hypothesize that antiarrhythmic effects of CNP are mediated by PDE2 (phosphodiesterase 2), which has the unique property to be stimulated by cGMP to primarily hydrolyze cAMP. Thus, CNP might promote beneficial effects of PDE2-mediated negative crosstalk between cAMP and cGMP signaling pathways. To determine antiarrhythmic effects of cGMP-mediated PDE2 stimulation by CNP, we analyzed arrhythmic events and intracellular trigger mechanisms in mice in vivo, at organ level and in isolated cardiomyocytes as well as in human-induced pluripotent stem cell-derived cardiomyocytes. In ex vivo perfused mouse hearts, CNP abrogated arrhythmia after ischemia/reperfusion injury. Upon high-dose catecholamine injections in mice, PDE2 inhibition prevented the antiarrhythmic effect of CNP. In mouse ventricular cardiomyocytes, CNP blunted the catecholamine-mediated increase in arrhythmogenic events as well as in ICaL, INaL, and Ca2+ spark frequency. Mechanistically, this was driven by reduced cellular cAMP levels and decreased phosphorylation of Ca2+ handling proteins. Key experiments were confirmed in human iPSC-derived cardiomyocytes. Accordingly, the protective CNP effects were reversed by either specific pharmacological PDE2 inhibition or cardiomyocyte-specific PDE2 deletion. CNP shows strong PDE2-dependent antiarrhythmic effects. Consequently, the CNP-PDE2 axis represents a novel and attractive target for future antiarrhythmic strategies.

PS-BPB09-7: ENDOTHELIAL CNP-GC-B SYSTEM PLAYS A PROTECTIVE ROLE IN THE DEVELOPMENT OF PULMONARY HYPERTENSION

Background: Pulmonary hypertension (PH) is a disease with a poor prognosis despite the development of various treatments, and a further therapeutic agent is required. C-type natriuretic peptide (CNP), one of the natriuretic peptide family, affects vasorelaxation and inhibition of vascular remodeling through its receptor guanylyl cyclase-B (GC-B). However, the beneficial effect of CNP on PH is still controversial. In this study, we examined the role of the CNP-GC-B pathway in the pathogenesis of PH. Methods and Results: To clarify the effect of the endogenous CNP-GC-B system on PH, we evaluated two types of PH models (monocrotaline pyrrole-induced and hypoxia-induced PH models) by using endothelial cell-specific CNP knockout mice (ecCNP-cKO), endothelial cell-specific GC-B knockout mice (ecGC-B-cKO), and smooth muscle cell-specific CG-B knockout mice (smGC-B-cKO). In both PH models, ecGC-B-cKO and ecCNP-cKO mice exacerbated PH compared to control cre-mice. Besides, mRNA levels of Edn1, IL6 and Ccl2 of the lung were significantly increased in the PH models of these mice. However, PH models of smGC-B-cKO mice showed no significant difference compared to those of control cre-mice. In cultured pulmonary arterial endothelial cells, synthesised CNP significantly attenuated PDGF- or hypoxia-induced increase in mRNA expression of Edn1, IL-6, and Ccl2. Moreover, continuous subcutaneous administration of synthesised CNP by osmotic mini-pump significantly ameliorated PH in PH model mice. Conclusion: CNP plays a protective role in the development of PH via endothelial GC-B through inhibiting endothelin-1 and inflammatory signals involvement. These data suggest CNP could be a novel therapeutic agent for PH.

Circulatory C-type natriuretic peptide reduces mucopolysaccharidosis-associated craniofacial hypoplasia in vivo.

Skeletal alterations in the head and neck region, such as midfacial hypoplasia, foramen magnum stenosis and spinal canal stenosis, are commonly observed in patients with mucopolysaccharidosis (MPS). However, enzyme replacement therapy (ERT), one of the major treatment approaches for MPS, shows limited efficacy for skeletal conditions. In this study, we analysed the craniofacial morphology of mice with MPS type VII, and investigated the underlying mechanisms promoting jaw deformities in these animals. Furthermore, we investigated the effects of C-type natriuretic peptide (CNP), a potent endochondral ossification promoter, on growth impairment of the craniofacial region in MPS VII mice when administered alone or in combination with ERT. MPS VII mice exhibited midfacial hypoplasia caused by impaired endochondral ossification, and histological analysis revealed increased number of swelling cells in the resting zone of the spheno-occipital synchondrosis (SOS), an important growth centre for craniomaxillofacial skeletogenesis. We crossed MPS VII mice with transgenic mice in which CNP was expressed in the liver under the control of the human serum amyloid-P component promoter, resulting in elevated levels of circulatory CNP. The maxillofacial morphological abnormalities associated with MPS VII were ameliorated by CNP expression, and further prevented by a combination of CNP and ERT. Histological analysis showed that ERT decreased the swelling cell number, and CNP treatment increased the width of the proliferative and hypertrophic zones of the SOS. Furthermore, the foramen magnum and spinal stenoses observed in MPS VII mice were significantly alleviated by CNP and ERT combination. These results demonstrate the therapeutic potential of CNP, which can be used to enhance ERT outcome for MPS VII-associated head and neck abnormalities.

Effect of C-type natriuretic peptide and amiodarone in Chinese patients with arrhythmia

Purpose: To compare the effect of C-type natriuretic peptide and amiodarone in Chinese patients with arrhythmia. &#x0D; Method: Chinese men and women aged 18 to 65 years with premature ventricular complexes (PVCs), were administered C-type natriuretic peptide (CNP) - test group or amiodarone (study group) in ratio of 1:1 for 96 h. Patients in CNP group received infusion of synthetic human CNP (10 pmol/kg/min) for an initial 2 h, and then for 30 min every day until discharge. Patients in amiodarone group received initial dose of 1000 mg over the first 24 h. Change in PVCs from baseline was the primary efficacy endpoint. Secondary efficacy endpoint includes: change in PVCs-related symptom scores from baseline, change in ejection fraction of left ventricle (LV), end‑diastolic diameter of LV, and cardiac events as composite outcome (CCE). The effect of both treatments on hemodynamic and electrocardiography parameters, and safety were evaluated. Data from 200 patients were analyzed. &#x0D; Results: The CNP showed significantly greater decrease in the number of PVCs when compared to amiodarone (p &lt; 0.005). Moreover, CNP was superior in alleviating PVCs- related symptoms when compared to amiodarone (p &lt; 0.005). A similar trend of favorable effect of CNP was observed for other endpoints. &#x0D; Conclusion: The C-type natriuretic peptide offers significantly greater benefits of suppressing PVCs and related symptoms, and demonstrates significantly greater improvement of cardiac function and clinical outcome. Thus, CNP can be considered for further investigation as a suitable alternative in the management of ventricular arrhythmia with PVC among Chinese patients.

C-Type Natriuretic Peptide (CNP) Could Improve Sperm Motility and Reproductive Function of Asthenozoospermia

This study is to analyze the effect of C-type natriuretic peptide (CNP) on sperm motility of asthenozoospermia and explore the influence mechanism of CNP on the reproductive system and sperm motility. Our results showed that the concentration of CNP in asthenospermia patients’ semen was lower than in normal people’s. The motility of sperm could be improved markedly by CNP and 8-Br-cGMP, while the effect of CNP was inhibited by NPR-B antagonist and KT5823. In the asthenozoospermia mouse model induced by CTX, CNP injection could improve sperm motility in the epididymis, alleviate tissue damage in the testes and epididymis, and increase testosterone levels. The asthenospermia mouse model showed high activity of MDA and proinflammatory factors (TNF-α, IL-6), as well as low expression of antioxidants (SOD, GSH-Px, CAT) in the testis and epididymis, but this situation could be significantly ameliorated after being treated with CNP. Those studies indicated that the concentration of CNP in the semen of asthenospermia patients is lower than in normal people and could significantly promote sperm motility through the NPR-B/cGMP pathway. In the asthenospermia mouse model induced by CTX, CNP can alleviate the damage of cyclophosphamide to the reproductive system and sperm motility. The mechanism may involve increasing testosterone and reducing ROS and proinflammatory factors to damage the tissue and sperm.

Roles of Natriuretic Peptides and the Significance of Neprilysin in Cardiovascular Diseases.

Simple SummaryThe endocrine effects of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in the vasculature, and the autocrine effects of ANP and BNP in cardiomyocytes are mediated by the common guanylyl cyclase A receptor (GC-A) expressed in various tissues and cell types. C-type natriuretic peptide (CNP) has paracrine actions that regulate vascular resistance and moderate myocardial stiffness via guanylyl cyclase B receptor (GC-B). Genetically modified mice have revealed the physiological roles of ANP and BNP in blood pressure, cardiac remodeling, and acute myocardial infarction. Molecular pathways in GC-A signaling specifically in cardiomyocytes were also investigated. ANP and BNP via the GC-A signaling phosphorylate regulator of G-protein signaling subtype 4 (RGS4) result in the inhibition of Gαq signaling coupled with angiotensin II type 1A receptor, inhibit the activation of transient receptor potential C6 (TRPC6), and attenuate genomic actions of the cardiac mineralocorticoid receptor (MR). Moreover, recent studies showed the physiological roles of CNP via GC-B in blood pressure and cardiac stiffness. Since natriuretic peptides are degraded by neprilysin (NEP), inhibiting NEP activity is expected to enhance the actions of natriuretic peptides. Experimental studies and clinical trials have shown the effect of NEP inhibition on cardiac remodeling, acute myocardial infarction, and hypertension.Atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) activate the guanylyl cyclase A receptor (GC-A), which synthesizes the second messenger cGMP in a wide variety of tissues and cells. C-type natriuretic peptide (CNP) activates the cGMP-producing guanylyl cyclase B receptor (GC-B) in chondrocytes, endothelial cells, and possibly smooth muscle cells, cardiomyocytes, and cardiac fibroblasts. The development of genetically modified mice has helped elucidate the physiological roles of natriuretic peptides via GC-A or GC-B. These include the hormonal effects of ANP/BNP in the vasculature, autocrine effects of ANP/BNP in cardiomyocytes, and paracrine effects of CNP in the vasculature and cardiomyocytes. Neprilysin (NEP) is a transmembrane neutral endopeptidase that degrades the three natriuretic peptides. Recently, mice overexpressing NEP, specifically in cardiomyocytes, revealed that local cardiac NEP plays a vital role in regulating natriuretic peptides in the heart tissue. Since NEP inhibition is a clinically accepted approach for heart failure treatment, the physiological roles of natriuretic peptides have regained attention. This article focuses on the physiological roles of natriuretic peptides elucidated in mice with GC-A or GC-B deletion, the significance of NEP in natriuretic peptide metabolism, and the long-term effects of angiotensin receptor-neprilysin inhibitor (ARNI) on cardiovascular diseases.

Effect of C-type natriuretic peptide on craniofacial skeletogenesis in mice during the pubertal growth spurt

ObjectiveThis study aimed to determine the effect of C-type natriuretic peptide (CNP) overexpression on craniofacial growth during the pubertal growth period in mice. DesignSix-week-old C57BL/6 mice were injected with pLIVE-Empty vectors (Control mice) and pLIVE-NPPC vectors (CNP mice) using the hydrodynamic method. Morphological analyses were performed at the age of 12 weeks. ResultsMicro–computed tomography (µCT) images showed significant (p < 0.05) hyperplasia in the maxilla along the sagittal plane (CNP mice: 13.754 mm, Control mice: 13.215 mm). Further, the images revealed significant bone overgrowth in the sagittal direction in the sphenoid (CNP mice: 6.936 mm, Control mice: 6.411 mm) and occipital (CNP mice: 4.051 mm, Control mice: 3.784 mm) bones in the CNP mice compared with that in the Control mice. Compared with SAP-Nppc-Tg mice in previous studies, although there was no effect on nose length and nasal bone length, the effect was sufficient to improve craniofacial hypogrowth. Furthermore, CNP promoted sagittal cranial growth by increasing the thickness of the spheno-occipital synchondrosis in organ cultures and nasal septal cartilage in micromass cultures, which were derived from 6-week-old mice. ConclusionsWe have previously shown that the elevated blood levels of CNP from the neonatal period affect midfacial skeletogenesis by promoting endochondral ossification using mice (SAP-Nppc-Tg mice). The overexpression of CNP, even in 6-weeks-old mice, promoted growth in the sagittal direction within the maxillary region. These findings indicate the therapeutic potential of CNP for the treatment of midfacial hypoplasia during the pubertal growth spurt.

C-type Natriuretic Peptide–induced PKA Activation Promotes Endochondral Bone Formation in Hypertrophic Chondrocytes

Longitudinal bone growth is achieved by a tightly controlled process termed endochondral bone formation. C-type natriuretic peptide (CNP) stimulates endochondral bone formation through binding to its specific receptor, guanylyl cyclase (GC)-B. However, CNP/GC-B signaling dynamics in different stages of endochondral bone formation have not been fully clarified, especially in terms of the interaction between the cyclic guanine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) pathways. Here, we demonstrated that CNP activates the cAMP/protein kinase A (PKA) pathway and that this activation contributed to the elongation of the hypertrophic zone in the growth plate. Cells of the chondrogenic line ATDC5 were transfected with Förster resonance energy transfer (FRET)–based cGMP and PKA biosensors. Dual-FRET imaging revealed that CNP increased intracellular cGMP levels and PKA activities in chondrocytes. Further, CNP-induced PKA activation was enhanced following differentiation of ATDC5 cells. Live imaging of the fetal growth plate of transgenic mice, expressing a FRET biosensor for PKA, PKAchu mice, showed that CNP predominantly activates the PKA in the hypertrophic chondrocytes. Additionally, histological analysis of the growth plate of PKAchu mice demonstrated that CNP increased the length of the growth plate, but coadministration of a PKA inhibitor, H89, inhibited the growth-promoting effect of CNP only in the hypertrophic zone. In summary, we revealed that CNP-induced cGMP elevation activated the cAMP/PKA pathway, and clarified that this PKA activation contributed to the bone growth–promoting effect of CNP in hypertrophic chondrocytes. These results provide insights regarding the cross-talk between cGMP and cAMP signaling in endochondral bone formation and in the physiological role of the CNP/GC-B system.

C-type natriuretic peptide stimulates chicken myoblast differentiation through NPRB/NPRC receptors and metabolism pathway

Skeletal muscle development is closely related with the amount of meat production and its quality in chickens. Natriuretic peptides (NPs) play an important role in myotube formation and fat oxidation of skeletal muscle in animals. The effect of C-type natriuretic peptide (CNP), an important member of the NPs, and its underlying molecular mechanisms in skeletal muscle are incompletely understood. Treatment of myoblasts with CNP led to enhanced proliferation/differentiation and significantly upregulated (P<0.05) mRNA expression of the CNP receptors natriuretic peptide receptor B (NPRB) and the clearance receptor C (NPRC). In cells exposed to CNP, 142 differentially expressed genes (84 up-regulation and 58 down-regulation) (P<0.05) were identified by RNA-sequencing compared with those in control cells. Sixteen genes were significantly enriched (P<0.05) in the metabolic pathway, and six of them (phospholipase C β4, phospholipase C β2, phosphoglycerate mutase 1, creatine kinase B, peroxiredoxin 6 and CD38) were closely related to skeletal muscle development and differentially expressed. In conclusion, CNP stimulated differentiation of myoblasts by upregulating expression of the NPRB and NPRC receptors and enriching key genes in the metabolic pathway.

C-type natriuretic peptide promotes adipogenic differentiation of goat adipose-derived stem cells via cGMP/PKG/ p38 MAPK signal pathway.

C-type natriuretic peptide (CNP) is a member of natriuretic peptide family, which plays unique roles in cardiovascular system. Once CNP binds to natriuretic peptide receptor B (NPR-B), NPR-B induces the production of cGMP, thereby activating PKG and downstream targets. The expression of NPR-B in adipose tissue led to a hypothesis that CNP could have roles involving in regulation of adipogenesis. However, there are few studies on the relationship between CNP and adipogenesis in goat. In the present study, goat adipose-derived stem cells (ADSCs) were isolated and employed to investigate the effect of CNP on adipogenesis in goat. The results showed that CNP significantly promoted adipogenic differentiation of goat ADSCs and also up-regulated the expression of brown adipose genes including uncoupling protein 1 (UCP-1) and peroxisome proliferator-activated receptor γ coactivator-1 α (PGC-1α). Furthermore, treatment with CNP increased the cGMP production and the phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK), MAPK activated protein kinase 2 (MK2), and activating transcription factor 2 (ATF2) during adipogenic differentiation. Conversely, PKG inhibitor Rp-8-CPT-cGMP or p38 MAPK specific inhibitor SB203580 abolished stimulative effect of CNP on adipogenic differentiation. Collectively, it is proved that CNP promoted adipogenic differentiation of goat ADSCs depending on the cGMP/PKG/p38 MAPK signal pathway.