Figure 6. MDRL regulates mitochondrial fission and apoptosis through targeting miR-361 and miR-484.

A. Knockdown of MDRL reduces the expression levels of miR-484. Cardiomyocytes were infected with adenoviral MDRL-siRNA or MDRL-sc. 24 h after infection miR-484 levels were analyzed by northern blot. B. Enforced expression of MDRL induces the increase of miR-484 levels. Cardiomyocytes were infected with adenoviral MDRL or β-gal. 24 h after infection miR-484 levels were analyzed by northern blot. C. MDRL reduces the inhibitory effect of miR-361 on miR-484 expression. Cardiomyocytes were infected with adenoviral miR-361, MDRL or β-gal. miR-484 expression levels were analyzed by northern blot. D. MDRL inhibits mitochondrial fission induced by A/R. Cardiomyocytes were infected with adenoviral MDRL or β-gal, and were exposed to A/R. The cells were stained with MitoTracker Green (left panel), Bar = 20 µm. The cells with fragmented mitochondria were counted (right panel). *p<0.05 vs A/R alone. E. MDRL inhibits apoptosis induced by A/R. Cardiomyocytes were infected with adenoviral MDRL or β-gal, then were exposed to A/R. Apoptosis was assessed by TUNEL assay. *p<0.05 vs A/R alone. F. MDRL could inhibit mitochondrial fission and apoptosis upon I/R. Intracoronary delivery of adenoviral constructs of MDRL or β-gal to the hearts was described in the section of Materials and Methods. Mice were subjected to 45 min ischemia and 3 h reperfusion. Counting of fragmented mitochondria and apoptosis were shown. *p<0.05 versus I/R alone. G. MDRL attenuates myocardial infarction upon I/R. Mice were treated as described in (F). The infarct sizes were shown. *p<0.05. Bar = 2 mm. H. Knockdown of miR-484 attenuates the inhibitory effect of MDRL on mitochondria fission and apoptosis. Cardiomyocytes were infected with the adenoviral MDRL, miR-484 antagomir or antagomir-NC, and then treated with A/R. Mitochondria fission and apoptosis were analyzed. *p<0.05.