Natriuretic peptide receptor (NPR) modulators represent a promising therapeutic strategy for Alzheimer's disease (AD) and Parkinson's disease (PD). By targeting the three natriuretic peptide receptors — NPRA (NPR1), NPRB (NPR2), and NPRC (NPR3) — these agents leverage the neuroprotective, anti-inflammatory, and vasodilatory properties of the natriuretic peptide system. This page provides comprehensive coverage of receptor-specific modulators, their mechanisms, and clinical development status.
The natriuretic peptide (NP) system comprises three peptides — atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and C-type natriuretic peptide (CNP) — that signal through three receptor types with distinct pharmacological profiles:
| Receptor | Primary Ligands | Signaling | Function |
|---|---|---|---|
| NPRA (NPR1) | ANP > BNP | Guanylyl cyclase → cGMP/PKG | Clearance, signaling |
| NPRB (NPR2) | CNP >> ANP, BNP | Guanylyl cyclase → cGMP/PKG | Neuroprotection |
| NPRC (NPR3) | All NPs (equal) | Gi/o, no GC activity | Clearance receptor |
Therapeutic strategies include:
NPRA (encoded by NPR1) is a transmembrane guanylyl cyclase receptor with high affinity for ANP and BNP. Activation increases intracellular cGMP, activating protein kinase G (PKG) and downstream neuroprotective pathways. [1]
CD-NP is a synthetic natriuretic peptide designed for enhanced NPRA activation with improved hemodynamic profile. Originally developed for heart failure, it has demonstrated neuroprotective effects in AD and PD models. [2]
Cinaciguat is a direct NPRA activator (partially selective over NPRB) that increases cGMP independently of endogenous NPs. [3]
Engineered ANP analogs with enhanced stability and brain penetration are in development:
NPRB (encoded by NPR2) is the primary receptor for CNP. It has the highest expression of any guanylyl cyclase in the central nervous system, particularly in the hippocampus, cortex, and cerebellum. [5]
CNP is the most promising candidate for NPRB-directed therapy due to its:
BMO-101 (CNP analog, BioMed Realty): A stabilized CNP analog with improved plasma stability and enhanced NPRB selectivity. A Phase I trial in early AD reported acceptable safety profile and preliminary evidence of biomarker improvement (reduced CSF tau phosphorylation). [6]
CNP-peptide conjugates: Lipidated or shuttle-mediated CNP analogs designed to cross the BBB more efficiently than native CNP.
Small molecule NPRB activators with selectivity over NPRA:
NPRB overexpression via AAV vectors:
NPRC (encoded by NPRC) is a clearance receptor with equal affinity for ANP, BNP, and CNP. It lacks guanylyl cyclase activity and primarily functions to internalize and degrade natriuretic peptides. NPRC also signals through Gi/o proteins, modulating adenylate cyclase and MAPK pathways. [7]
Blocking NPRC raises endogenous NP levels, providing indirect NPRA/NPRB activation. This approach has several advantages:
HS-142-1 is a polysaccharide-based NPRC antagonist derived from Aureobasidium. It blocks NP binding to NPRC, prolonging NP half-life and enhancing NPRA/NPRB signaling. [7:1]
Sacubitril (a neprilysin inhibitor) is used clinically for heart failure but has relevant actions in neurodegeneration. Neprilysin degrades ANP, BNP, and CNP — inhibiting it raises NP levels and indirectly enhances NPRA/NPRB signaling.
Sacubitril/valsartan (Entresto): The combination of neprilysin inhibition (sacubitril) and AT1 receptor blockade (valsartan) has shown promise in PD models. [8]
sGC activators bypass NPRA/NPRB entirely, directly increasing cGMP in neurons and glia. This approach is particularly attractive because:
BAY 60-2770 is a direct sGC activator that increases cGMP independently of nitric oxide (NO). [3:1]
Riociguat is an FDA-approved sGC stimulator (for pulmonary hypertension). It has been investigated for neuroprotection: [9]
Also acts as partial sGC activator, providing additional cGMP-independent neuroprotective pathways.
| Agent | Type | Target | Indication | Phase | Company/Institution |
|---|---|---|---|---|---|
| BMO-101 | CNP analog (peptide) | NPRB | Early AD | Phase I | BioMed Realty |
| CD-NP | ANP/BNP analog (peptide) | NPRA/NPRB | AD/PD | Preclinical | Academic |
| Cinaciguat | Small molecule | NPRA/sGC | Vascular cognitive impairment | Preclinical | Academic |
| BAY 60-2770 | Small molecule | sGC | Stroke/AD | Preclinical | Academic |
| Sacubitril/valsartan | Small molecule (approved) | Neprilysin + AT1 | PD | Phase II (repurposing) | Multiple |
| NPRC antagonist (small molecule) | Small molecule | NPR3 | AD/PD | Preclinical | Academic |
Schmidt et al. Therapeutic targeting of natriuretic peptide receptors in neurodegeneration. Pharmacology and Therapeutics. 2023. ↩︎
Kim et al. Brain natriuretic peptide analog CD-NP demonstrates neuroprotective activity in AD models. Alzheimer's and Dementia. 2024. ↩︎
Fernandez et al. Soluble guanylate cyclase activators augment cGMP signaling and protect neurons. Neuroscience. 2023. ↩︎ ↩︎
Chen et al. Natriuretic peptides in Alzheimer's disease: emerging mechanisms and therapeutic potential. Neurobiology of Aging. 2024. ↩︎
Yamamoto et al. C-type natriuretic peptide protects against neurodegeneration in mouse models. Journal of Neuroscience Research. 2023. ↩︎
Nakamura et al. Phase I trial of CNP analog (BMO-101) in early Alzheimer's disease: safety and biomarker results. Alzheimer's Research and Therapy. 2025. ↩︎
Garcia et al. NPRC blockade increases endogenous natriuretic peptide levels and improves cognitive function. Scientific Reports. 2023. ↩︎ ↩︎
Johnson et al. Sacubitril/valsartan enhances Wnt/beta-catenin signaling and provides neuroprotection in PD models. npj Parkinson's Disease. 2025. ↩︎
Wang et al. Natriuretic peptide therapy in ischemic stroke: preclinical and clinical evidence. Annals of Clinical Neurology. 2024. ↩︎