TSLP mitigates post-infarction myocardial remodeling by promoting eosinophil recruitment and inhibiting JAK1–STAT5-mediated ferroptosis

Acute myocardial infarction (AMI) remains a leading cause of morbidity and mortality globally, often leading to heart failure due to excessive inflammation and fibrosis. Thymic stromal lymphopoietin (TSLP), a cytokine primarily involved in immune regulation, has recently been identified as a key player in cardiovascular health. However, its role in modulating inflammation and fibrosis after AMI is not fully understood. This study investigates how TSLP mediates anti-inflammatory effects and reduces fibrosis, ultimately improving heart function in a mouse model of AMI. We established a TSLP knockout mouse strain and performed left anterior descending (LAD) coronary artery ligation to create an AMI model. This was used to investigate the role of TSLP in eosinophil (EOS) recruitment and fibrosis alleviation. Additionally, EOS depletion, JAK-STAT pathway inhibition, and ferroptosis were employed to analyze potential mediating factors. The extent of cardiac tissue fibrosis was evaluated using histological staining. Inflammatory cytokine levels and EOS were assessed through ELISA and flow cytometry. Western blotting was conducted to detect proteins related to ferroptosis and the JAK-STAT pathway. TSLP deficiency significantly exacerbated myocardial remodeling in AMI mice, while TSLP treatment markedly reduced cardiac fibrosis following AMI, with a notable decrease in collagen deposition within the heart tissue. In Transwell assays, TSLP effectively recruited EOSs, and in vivo experiments demonstrated that TSLP promoted the resolution of acute-phase inflammation (within one week), a process that could be blocked by EOS depletion. TSLP promotes the resolution of post-infarction inflammation and inhibits fibrosis by recruiting EOSs to the heart. This highlights the potential of targeting the TSLP-EOS axis as a therapeutic strategy to improve cardiac function and reduce post-AMI complications.