The CNP/NPR-B/cGMP Axis is a Therapeutic Target in Calcific Aortic Stenosis

Reactivation of Oxidized Soluble Guanylate Cyclase as a Novel Treatment Strategy to Slow Progression of Calcific Aortic Valve Stenosis: Preclinical and Randomized Clinical Trials to Assess Safety and Efficacy

BACKGROUND

Pharmacological treatments for fibrocalcific aortic valve stenosis (FCAVS) have been elusive for >50 years. Here, we tested the hypothesis that reactivation of oxidized sGC (soluble guanylate cyclase), the primary receptor for nitric oxide, with ataciguat is a safe and efficacious strategy to slow progression of FCAVS.

METHODS

We used quantitative real-time reverse transcription polymerase chain reaction, Western blotting, and immunohistochemistry to characterize sGC signaling and the biological effects of ataciguat on signaling cascades related to nitric oxide, calcification, and fibrosis in excised human aortic valve tissue, aortic valve interstitial cells, and mouse aortic valves. We then conducted randomized, placebo-controlled phase I (14-day safety/tolerance) and phase II (6-month efficacy) trials in patients with moderate aortic valve stenosis.

RESULTS

In excised human tissue, we found robust losses in sGC signaling despite upregulation of sGC subunits. In vitro, ataciguat increased sGC signaling and reduced BMP2 (bone morphogenetic protein 2) signaling in aortic valve interstitial cells. In mice with established FCAVS, treatment with ataciguat attenuated BMP signaling and slowed progression of valve calcification and dysfunction. In a phase I, randomized, placebo-controlled trial, treatment with ataciguat for 2 weeks was safe and well tolerated in patients with moderate FCAVS (https://www.clinicaltrials.gov; Unique identifier: NCT02049203). In a separate phase II, randomized, placebo-controlled trial, treatment with ataciguat for 6 months slowed the progression of aortic valve calcification and tended to slow the progression of valvular and ventricular dysfunction in patients with moderate FCAVS (https://www.clinicaltrials.gov; Unique identifier: NCT02481258).

CONCLUSIONS

Collectively, this study highlights the therapeutic potential of the targeted restoration of the diseased/inactive form of sGC for treatment of FCAVS.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02049203. URL: https://www.clinicaltrials.gov; Unique identifier: NCT02481258.

Targeted inhibition of NPR3/MAPK pathway enhances dental pulp stem cell multipotency: Mechanistic validation based on ligustrazine (TMP)

BACKGROUND

The multipotency of dental pulp stem cells (DPSCs) plays a crucial role in dental tissue regeneration, yet its regulatory mechanisms remain incompletely understood. This study aimed to investigate the role of natriuretic peptide receptor 3 (NPR3) in regulating DPSCs functions and validate the mechanism of its targeted inhibitor ligustrazine (TMP).

METHODS

NPR3 expression in DPSCs was examined by Western blot and immunohistochemistry. The effects of NPR3 on DPSCs colony formation, migration, and differentiation were investigated through overexpression and knockdown strategies. The relationship between NPR3 and ERK1/2 pathway was explored using molecular biological approaches. High-throughput drug screening was employed to identify TMP as an NPR3 inhibitor, followed by mechanism validation.

RESULTS

NPR3 was highly expressed in mature odontogenic DPCs, with its expression levels closely correlated with DPSCs functions. Functional assays demonstrated that NPR3 inhibited DPSCs colony formation, migration, and differentiation capabilities, while NPR3 knockdown significantly enhanced these functions. Mechanistic studies revealed that NPR3 influenced DPSCs functions through positive regulation of ERK1/2 phosphorylation. Through high-throughput screening, we identified TMP as a specific NPR3 inhibitor that promoted DPSCs functions. Rescue experiments further confirmed that NPR3 overexpression or ERK1/2 inhibitor SCH772984 attenuated TMP-induced enhancement, validating TMP's action through the NPR3/MAPK pathway.

CONCLUSION

This study reveals the crucial role of the NPR3/MAPK pathway in regulating DPSCs multipotency and demonstrates that TMP enhances DPSCs functions through targeted inhibition of this pathway, providing new therapeutic strategies and drug targets for dental tissue regeneration.

Sacubitril/Valsartan inhibits M1 type macrophages polarization in acute myocarditis by targeting C-type natriuretic peptide

Studies have shown that Sacubitril/valsartan (Sac/Val) can reduce myocardial inflammation in myocarditis mice, in addition to its the recommended treatment of heart failure. However, the underlying mechanisms of Sac/Val in myocarditis remain unclear. C-type natriuretic peptide (CNP), one of the targeting natriuretic peptides of Sac/Val, was recently reported to exert cardio-protective and anti-inflammatory effects in cardiovascular systems. Here, we focused on circulating levels of CNP in patients with acute myocarditis (AMC) and whether Sac/Val modulates inflammation by targeting CNP in experimental autoimmune myocarditis (EAM) mice as well as LPS-induced RAW 264.7 cells and bone marrow derived macrophages (BMDMs) models. Circulating CNP levels were higher in AMC patients compared to healthy controls, and these levels positively correlated with the elevated inflammatory cytokines IL-6 and monocyte count. In EAM mice, Sac/Val alleviated myocardial inflammation while augmenting circulating CNP levels rather than BNP and ANP, accompanied by reduction in intracardial M1 macrophage infiltration and expression of inflammatory cytokines IL-1β, TNF-α, and IL-6. Furthermore, Sac/Val inhibited CNP degradation and directly blunted M1 macrophage polarization in LPS-induced RAW 264.7 cells and BMDMs. Mechanistically, the effects might be mediated by the NPR-C/cAMP/JNK/c-Jun signaling pathway apart from NPR-B/cGMP/NF-κB pathway. In conclusion, Sac/Val exerts a protective effect in myocarditis by increasing CNP concentration and inhibiting M1 macrophages polarization.

Natriuretic peptide pathways in heart failure: further therapeutic possibilities

The discovery of the heart as an endocrine organ resulted in a remarkable recognition of the natriuretic peptide system (NPS). Specifically, research has established the production of atrial natriuretic peptide (ANP) and B-type natriuretic peptide (BNP) from the heart, which exert pleiotropic cardiovascular, endocrine, renal, and metabolic actions via the particulate guanylyl cyclase A receptor (GC-A) and the second messenger, cGMP. C-type natriuretic peptide (CNP) is produced in the endothelium and kidney and mediates important protective auto/paracrine actions via GC-B and cGMP. These actions, in part, participate in the efficacy of sacubitril/valsartan in heart failure (HF) due to the augmentation of the NPS. Here, we will review important insights into the biology of the NPS, the role of precision medicine, and focus on the phenotypes of human genetic variants of ANP and BNP in the general population and the relevance to HF. We will also provide an update of the existence of NP deficiency states, including in HF, which provide the rationale for further therapeutics for the NPS. Finally, we will review the field of peptide engineering and the development of novel designer NPs for the treatment of HF. Notably, the recent discovery of a first-in-class small molecule GC-A enhancer, which is orally deliverable, will be highlighted. These innovative designer NPs and small molecule possess enhanced and novel properties for the treatment of HF and cardiovascular diseases.