ACTA2 and myocardial ischemia: Additionally, COL1A1hiNR4A1low fibroblasts exhibit elevated expression of other myofibroblast markers such as POSTN and ACTA2 (Supplementary Figures S1, S2, and Table S3), These findings highlight the potential of this fibroblast subset to actively contribute to the progression of cardiac fibrosis in patients with IHD.