Fig. 1: CircHIPK3 is upregulated concomitantly with accelerated autophagy in hypoxia/reoxygenation (H/R)-stimulated cardiomyocytes and ischemia/reperfusion (I/R)-stimulated myocardium.

A Mice were subjected to 60 min of ischemia and 3 h of reperfusion. Representative transmission electron microscopy (TEM) images of hearts show the presence of autophagosomes (red arrow). Scale bar = 1 μm. B RT-qPCR analysis of circHIPK3 expression in mouse heart samples undergoing I/R or sham treatment. n = 3. C LC3-II and P62 expression were analyzed by western blotting in H/R (6 h hypoxia followed by 4 h reoxygenation)-stimulated cardiomyocytes. n = 3. D Increased expression of circHIPK3 in H/R-stimulated cardiomyocytes. n = 9. E Cardiomyocytes were transfected with negative control (LV), circHIPK3 overexpression vector, or circHIPK3 siRNA (si-circHIPK3) for 48 h. F Representative electron microscope analysis of autophagosomes in cardiomyocytes. Scale bar = 2 μm. G LC3-II and Beclin 1 expression were analyzed by western blotting in cardiomyocytes. *P < 0.05 compared with the sham or normal group. #P < 0.05 compared with the H/R group.