Fig. 1.

Active participation of tdTomato-labeled Cd34-lineage cells in I/R injury. A Schematic depicting heart tissue harvested from C57BL6 mice for scRNA-seq. The left anterior descending coronary artery (LAD) was temporarily ligated and reperfusion was conducted 45 min later. Sham surgery was performed by only opening the thoracic cavity without ligation. Heart tissue was harvested 1 and 2 weeks after surgery, along with hearts from the sham group. Single cells were then isolated from the left ventricle, sorted by fluorescence-activated cell sorting (FACS) and subjected to scRNA-seq (n = 3 mice per group). B The experimental scheme whereby Cd34-CreER^T2; R26-tdTomato (Cre/TDT) mice were given tamoxifen 1 week before I/R or sham surgery. Hearts were harvested at 3, 7, and 14 days after surgery for different tests. C Echocardiographic measurements of LVEF, LVEDD, and left ventricle end-systolic diameter (LVESD) in wild-type (WT) and Cre/TDT mice. N = 7 mice per group. Data were shown as mean ± SEM, ns, not significant, by Student’s t test. D Representative cross sections of Cre/TDT ventricles stained with tdTomato and CD34. E Representative flow cytometry analyses of freshly isolated bone marrow cells from Cre/TDT mice stained with tdTomato and APC-conjugated CD34 antibody. F Representative cross sections of Cre/TDT ventricles stained with tdTomato and CD31. G Representative cross sections of Cre/TDT ventricles stained with tdTomato and CD45. H Representative cross sections of Cre/TDT kidney and spleen tissue stained with tdTomato and CD34. I Representative tdTomato expression on cross sections of Cre/TDT ventricles from 1 week and 2 weeks post-I/R in border zones and remote zones. J Representative cross sections of Cre/TDT ventricles stained with Ki67 and EdU. Magnification in each image was the magnification of the boxed region, arrows indicated co-staining cells. Scale bars, 100 μm, and 20 μm in magnification images. tdT tdTomato