BACKGROUND: Atherosclerosis is frequently associated with both an increased incidence and accelerated development of cancer. However, the impact of atherosclerosis progression on the efficacy of tumor surveillance by cytotoxic immune cells, particularly natural killer (NK) cells, remains poorly understood. This study aims to explore how atherosclerosis affects NK cell–mediated tumor surveillance in both animal models and humans. METHODS: We analyzed peripheral blood NK cells from patients with atherosclerosis with early-stage (<50% stenosis) versus advanced-stage (≥50% stenosis) coronary artery lesions by flow cytometry to assess NK cell frequency, PPARα (peroxisome proliferator–activated receptor alpha) expression, and IFN-γ (interferon gamma) production. In parallel, we used atherosclerotic plaque progression and regression models, including high-fat diet-fed Apo –/– mice and aortic arch transplantation into wild-type, Apoe –/– , Rag1 –/– , and NK cell–specific PPARα knockout ( Ppara flox/flox Ncr1 Cre/+ ) mice. NK cell phenotype and function were evaluated by flow cytometry for immune checkpoint molecules (PD-1 [programmed cell death protein-1], TIM-3 [T-cell immunoglobulin and mucin-domain containing-3], LAG-3 [lymphocyte activation gene-3], and TIGIT [T-cell immunoglobulin and ITIM domain]) and effector cytokines (IFN-γ, GZMB [granzyme B]). Antitumor capacity was assessed in B16F10 melanoma and ID8 ovarian cancer models in atherosclerosis mice, with or without a PPARα agonist (oleoylethanolamide) or an mTOR (mechanistic target of rapamycin kinase) agonist (MHY1485) treatment. Mechanistic studies included immunoblotting for mTOR pathway components and transcriptomic correlation analyses (GSE94044, GSE24495). RESULTS: We found that atherosclerotic plaques induced PPARα deficiency in NK cells, which impaired their cytotoxicity and weakened tumor immunosurveillance. Mechanistically, PPARα-deficient NK cells exhibited elevated immune checkpoint expression, an exhaustion phenotype, and markedly diminished mTOR signaling. Administration of the PPARα agonist oleoylethanolamide restored NK cell effector function and enhanced tumor-killing efficacy in vivo, whereas mTOR agonism partially rescued the defect caused by PPARα loss. These findings underscore the suppressive effects of arterial plaques on NK cell–mediated antitumor immunity and suggest PPARα compensation as a potential immunotherapeutic strategy. CONCLUSIONS: Our study unveils a novel association between atherosclerosis and the attenuation of NK cell antitumor immunity. Specifically, plaque-induced downregulation of PPARα in NK cells leads to uncontrolled immune checkpoint expression, causing NK cell exhaustion and diminished antitumor function. Pharmacological enhancement of PPARα signaling rejuvenated NK cell activity and reduced tumor growth in atherosclerosis. Therefore, targeting PPARα offers a promising therapeutic approach for cancer treatment and prevention in individuals with atherosclerosis.
BACKGROUND: Recanalization failure after ischemic stroke remains a major clinical challenge, partly because cerebral thrombi display marked spatial heterogeneity that is poorly reproduced by experimental models. Here, we engineered a translational human blood–based thrombus platform that recapitulates key histological features of patient-derived stroke clots. METHODS: Under controlled conditions, the platform generated reproducible thrombi with pronounced interthrombus and intrathrombus heterogeneity, including alternating red blood cell–rich and platelet-rich territories. Multiscale structural and biochemical analyses confirmed the successful replication of the clinical biphasic organization associated with resistance to rtPA (recombinant tissue-type plasminogen activator): a compact outer fibrin shell containing focal accumulations of plasminogen activator inhibitor-1, and a dense inner core further stabilized by neutrophil extracellular traps. RESULTS: Functional thrombolysis assays demonstrated that this architecture directly dictates lytic susceptibility. Specifically, artificially breaching the outer fibrin shell (halved thrombi) significantly accelerated early rtPA-mediated lysis, proving its role as an effective physical barrier. Furthermore, lytic response was inherently linked to clot composition: platelet-rich thrombi with dense plasminogen activator inhibitor-1 and neutrophil extracellular trap networks exhibited profound resistance to standard rtPA compared with red blood cell–rich clots. Supporting the platform’s translational relevance, this structural resistance was successfully overcome by clinically relevant strategies, including tenecteplase and adjunctive DNAse, consistent with observations from human stroke cohorts. CONCLUSIONS: By accurately reproducing the spatial organization and differential thrombolytic responses of human cerebral thrombi, this translational framework provides a robust preclinical tool to dissect lytic resistance and evaluate next-generation precision reperfusion therapies. Furthermore, developing robust ex vivo human platforms is increasingly critical to align with the replacement, reduction, refinement ethical guidelines for animal research.
BACKGROUND: Aortic aneurysm and dissection (AAD) is a life-threatening vascular disease that currently lacks effective pharmacological therapies. Clinical evidences suggest that aspirin may exert a protective effect on AAD, but the underlying molecular mechanism is still unclear at present.METHODS: Three mouse animal models of AAD and H2O2-induced ferroptosis model in human aortic vascular smooth muscle cells (HAVSMCs) were established. On this basis, RNA sequencing was performed to investigate potential molecular mechanisms, and further experiments were conducted using STING (stimulator of interferon genes) agonist to confirm the mechanisms.RESULTS: Aspirin was found to ameliorate the progression of AAD in the beta-aminopropionitrile and CaPO4 mouse models. Interestingly, aspirin reduced mortality in mice but did not reduce the incidence of AAD in the beta-aminopropionitrile + angiotensin II model. Furthermore, aspirin inhibited H2O2-induced ferroptosis in HAVSMCs and suppressed activation of cGAS (cyclic GMP-AMP synthase)-STING signaling pathway. Activation of STING with STING agonist markedly increased STING, TBK1 (TANK-binding kinase 1), and IRF3 (interferon regulatory factor 3) phosphorylation and abolished the protective effect of aspirin against H2O2-induced ferroptosis in HAVSMCs. Western blot and immunofluorescence results indicated significant activation of the cGAS-STING signaling pathway following treatment with STING agonist. Coimmunoprecipitation analysis revealed that cGAS acetylation was considerably enhanced in HAVSMCs after aspirin treatment. Additionally, administration of aspirin and dimeric amidobenzimidazole compound 3 showed that dimeric amidobenzimidazole abolished the protective effect of aspirin in the CaPO4 model. Coimmunoprecipitation results indicated that aspirin promoted cGAS acetylation in mouse aortic tissue. Western blot and immunohistochemistry results also confirmed that the dimeric amidobenzimidazole compound 3 activated phosphorylation of STING, TBK1, and IRF3 and significantly negatively regulated the expression of GPX4 (glutathione peroxidase). In the beta-aminopropionitrile model, dimeric amidobenzimidazole also abolished the protective effect of aspirin.CONCLUSIONS: Aspirin confers a protective effect against AAD by promoting cGAS acetylation and inhibiting the cGAS-STING signaling pathway and ferroptosis in VSMC.
