N-p-trans-Coumaroyltyramine Improves Myocardial Ischemia-Reperfusion Injury: From Cellular Protection to Animal Model Validation and the Discovery of the Target Tcap.

Myocardial ischemia-reperfusion injury (MIRI) significantly limits the clinical benefits of reperfusion therapy, underscoring a pressing need for effective interventions. This study examines the cardioprotective effects and underlying mechanisms of the natural amide alkaloid N-p-trans-Coumaroyltyramine (p-CT). Using hypoxia/reoxygenation (H/R) models in neonatal rat cardiomyocytes and in vivo rat MIRI models, we assessed p-CT pretreatment on cell viability, cardiac function, serum injury markers (lactate dehydrogenase, creatine kinase-MB, cardiac troponin T, and myoglobin), myocardial histopathology, ultrastructural alterations, and infarct size. The systematic screening and validation of potential targets were conducted via label-free quantitative proteomics, molecular docking, and Western blot. The results demonstrated that p-CT pretreatment dose-dependently mitigated H/R-induced cellular injury, improved cardiac function in MIRI rats, reduced serum markers of myocardial damage, alleviated pathological and ultrastructural injury in myocardial tissue, and significantly diminished infarct size. Proteomic analysis revealed 19 differentially expressed proteins specifically reversed by p-CT, with Titin-cap (Tcap) exhibiting the most pronounced downregulation in the MIRI model-a change effectively restored by p-CT pretreatment. Molecular docking indicated strong binding affinity between p-CT and Tcap protein. In summary, p-CT represents a promising cardioprotective agent, likely exerting its effects by targeting Tcap protein and upregulating its expression, thereby helping preserve cardiomyocyte structural and functional integrity.