Nanoparticle-Mediated Delivery of Adenosine 5′-Monophosphate Enhances 5-Oxoprolinase Activity to Mitigate Oxidative Stress in Heart Failure

Oxidative stress, a key driver of heart failure progression, is exacerbated by 5-oxoproline accumulation due to reduced 5-oxoprolinase (OPLAH) activity. While enhancing OPLAH function represents a promising therapeutic strategy, effective intracellular delivery of activity-modulating compounds remains highly challenging. Here, we develop a comprehensive approach combining high-throughput screening technology and advanced nanocarrier design to address effective intracellular delivery. Through the screening of an FDA-approved compound library, we identify adenosine 5′-monophosphate (AMP) as a novel OPLAH activator, demonstrating direct modulation through thermal shift assay and a dose-dependent activation via liquid chromatography mass spectrometry (LC-MS/MS) analysis. To overcome the AMP's limited cellular permeability, we engineer acetalated dextran spermine-modified nanoparticles (AcDXSp-NPs) with optimized physicochemical properties for efficient intracellular delivery. The AMP-loaded nanoparticles exhibit a high encapsulation efficiency (>70%) and controlled pH-dependent release. In cell-based studies, these nanocarriers significantly enhance OPLAH activity, evidenced by a >50% increase in ¹³C₅-glutamate production from the isotope-labeled ¹³C₅-5-oxoproline. This integrated approach, combining enzyme activation with advanced delivery systems, may present a promising therapeutic strategy for oxidative stress-related conditions, particularly conditions like heart failure; it also demonstrates the potential of materials-based solutions for challenging therapeutic targets.