Prostaglandin E2-EP2 signalling drives vascular aging by inducing mitochondrial dysfunction and pro-inflammatory phenotypic switching via QSOX1 up-regulation

Background Vascular aging is a fundamental driver of age-related chronic diseases, in which the phenotypic switching of vascular smooth muscle cells (VSMCs) from a contractile to a pro-inflammatory state plays a critical role. While vascular aging involves multiple pathological processes including endothelial dysfunction, the contribution of VSMC transitions to vascular remodeling and inflammation is particularly significant. However, the specific metabolic triggers and molecular mechanisms governing this VSMC transition during aging remain largely undefined. Purpose This study aimed to identify key metabolic-signaling axes that drive VSMC pro-inflammatory transitions and to characterize the molecular mechanisms by which arachidonic acid-derived metabolites influence mitochondrial fitness during vascular aging. Furthermore, we sought to utilize high-resolution protein structures to facilitate structure-based drug discovery for novel therapeutic interventions targeting vascular senescence. Methods An integrated approach was employed, combining multi-omics analysis—including single-cell RNA sequencing, proteomics, and targeted metabolomics—of naturally aging C57BL/6J mice (2 to 22 months old). Mitochondrial function (ATP production, ROS levels, and membrane potential) was assessed in VSMC senescence models induced by H2O2 or doxorubicin. Functional impacts were investigated using pharmacological inhibition (EP2-selective antagonist PF-04418948) and genetic knockdown via siRNA. Furthermore, cryo-electron microscopy (cryo-EM) was utilized to explore the structural basis of antagonist recognition of EP2 receptor for further identification of potential lead compounds. Results Multi-omics profiling revealed that prostaglandin PGE2 levels and its specific receptor EP2 are significantly and consistently upregulated in aging aortas and senescent VSMCs. Activation of the PGE2-EP2 axis was found to drive VSMC pro-inflammatory switching and induce severe mitochondrial dysfunction, characterized by reduced ATP production and elevated oxidative stress. Proteomic integration further identified Quiescin sulfhydryl oxidase 1 (QSOX1) as a key downstream mediator upregulated by PGE2-EP2 signaling. Pharmacological blockade of EP2 or siRNA-mediated knockdown of QSOX1 effectively rescued mitochondrial fitness and attenuated cellular senescence markers, including p53 and p21. Additionally, our cryo-EM analysis of the EP2-inhibitor complex provided high-resolution structural insights into the ligand-binding pocket, providing a critical foundation for drug screening and optimization. Conclusions The PGE2-EP2-QSOX1 axis is a critical metabolic-signaling cascade promoting VSMC phenotypic transition and mitochondrial impairment during vascular aging. Targeting this axis through structure-based drug discovery offers a promising therapeutic strategy to delay vascular aging and mitigate its associated cardiovascular risks.Figure 1Figure 2