biostudies-literatureXu SMinistry of Science and Technology of People’s republiC of CHINAChina Postdoctoral Science FoundationNational Natural Science Foundation of Chinae187072https://www.ebi.ac.uk/biostudies/studies/S-EPMC12128982biostudies-literatureUnknown10(9)The inflammatory response after myocardial infarction (MI) is a precisely regulated process that greatly affects subsequent wound healing and remodeling. However, understanding about the process is still limited. Macrophages are critically involved in inflammation resolution after MI. Krüppel-like factor 9 (Klf9) is a C2H2 zinc finger-containing transcription factor that has been implicated in glucocorticoid regulation of macrophages. However, the contribution of Klf9 to macrophage phenotype and function in the context of MI remains unclear. Our study revealed that KLF9 deficiency resulted in higher mortality and cardiac rupture rate, as well as a considerable exacerbation in cardiac function. Single-cell RNA sequencing and flow cytometry analyses revealed that, compared with WT mice, Klf9JCI insightKlf9 promotes the repair of myocardial infarction by regulating macrophage recruitment and polarization.PMC121289822019M66163881600308,8200024STI2030-Major ProjectsLi HChe WXu SHan JYue WLiu FXu YLi NfalseKlf9 promotes the repair of myocardial infarction by regulating macrophage recruitment and polarization.The inflammatory response after myocardial infarction (MI) is a precisely regulated process that greatly affects subsequent wound healing and remodeling. However, understanding about the process is still limited. Macrophages are critically involved in inflammation resolution after MI. Krüppel-like factor 9 (Klf9) is a C2H2 zinc finger-containing transcription factor that has been implicated in glucocorticoid regulation of macrophages. However, the contribution of Klf9 to macrophage phenotype and function in the context of MI remains unclear. Our study revealed that KLF9 deficiency resulted in higher mortality and cardiac rupture rate, as well as a considerable exacerbation in cardiac function. Single-cell RNA sequencing and flow cytometry analyses revealed that, compared with WT mice, Klf92025-01-01T00:00:00Z2025 May2026-06-02T00:16:03.211Z2026-05-24T03:07:33.396ZS-EPMC121289824019814110.1172/jci.insight.187072