Portulaca oleracea L. Extract and Its Alkaloid Oleracein E Alleviates Cardiac Remodeling and Heart Failure in Mice by Targeting STAT2 Through the MAPK Signaling Inflammatory Pathway

Abstract

Hypertensive heart failure pathogenesis involves angiotensin II (Ang II)-mediated mechanisms through both hemodynamic overload and direct cellular signaling pathways. This study investigates the therapeutic potential of Portulaca oleracea L. (POL) extract and its active constituent Oleracein E (OE) in attenuating Ang II-induced pathological cardiac remodeling and subsequent heart failure progression. An experimental model of hypertensive heart failure was established in C57BL/6 mice through continuous subcutaneous infusion of Ang II for 4 weeks, with Oleracein E (OE) intervention administered during the final 2 weeks of the protocol. To elucidate the molecular mechanisms underlying OE's cardioprotective effects, we employed an integrated approach combining RNA sequencing analysis, molecular docking simulations, and target validation through drug affinity response target stability (DARTS) and cellular thermal shift assay (CETSA) techniques. The experimental results demonstrated that both POL extract and its active component OE exerted significant cardioprotective effects against Ang II-induced cardiac dysfunction in murine models, primarily through attenuation of pathological cardiac hypertrophy and suppression of inflammatory responses. Transcriptomic profiling via RNA sequencing identified the MAPK signaling pathway as a critical mediator of these protective effects. Subsequent transcription factor analysis revealed STAT2 as a key regulatory component in this pathway. Importantly, OE treatment effectively mitigated inflammatory responses in both in vivo cardiac tissues and in vitro cultured cardiomyocytes by specifically inhibiting the Ang II-activated MAPKs/STAT2 signaling cascade. Genetic ablation experiments further confirmed the essential role of this pathway, as the anti-inflammatory efficacy of OE was completely abolished in cardiomyocytes with MAPKs or STAT2 deficiency. Molecular interaction studies employing in silico docking simulations combined with experimental validation through DARTS and CETSA techniques provided direct evidence of physical binding between OE and the STAT2 protein. Our findings demonstrate that Oleracein E (OE) confers cardioprotection against Ang II-induced myocardial injury through a novel mechanism involving STAT2 targeting and subsequent suppression of MAPK signaling-mediated inflammatory cascades. These results not only elucidate a previously unrecognized pharmacological pathway but also suggest that OE and its derivatives hold significant therapeutic promise for the clinical management of hypertensive heart failure, potentially offering a targeted approach to modulate pathological cardiac remodeling.