Abstract 14011: Cardiomyocytes Mediate Anti-Angiogenesis in Type 2 Diabetic Rats through Exosomal Transferring miR-320 into Endothelial Cells
Background: Exosomes, nano-vesicles naturally released from living cells, have been well recognized to play critical roles in mediating cell-to-cell communication. Given that diabetic hearts exhibit insufficient angiogenesis, it will be significant to test whether diabetic cardiomyocyte-derived exosomes posses any capacity in regulating angiogenesis.
Methods and Results: Cardiomyocytes were isolated from GK rats (8-week old), a commonly used model of type-2 diabetes, and age-matched control Wistar rats, followed by culturing for 48 hours. Cell culture supernatants were then harvested for exosome isolation by differential centrifugation. Subsequently, these exosomes were added to MCECs, a cardiac endothelial cell line, for angiogenesis assay. We observed that MCEC proliferation was significantly reduced in a dose-dependent manner when exposed to exosomes collected from GK myocytes (ExoGK) for 24h, compared with those treated with exosomes derived from Wistar myocytes (ExoCtl). Using a scratch wound migration assay, we found that migration was attenuated by 62±5% in ExoGK-treated MCECs, compared to controls. Similarly, Matrigel tube-like formation assay exhibited that the mean tube length was shorter by 45±4% in ExoGK-treated MCECs than that of controls (p<0.01). RNA sequence profiling revealed that ExoGK contained a significant amount of miR-320, which was validated by RT-PCR, compared with control exosomes. Accordingly, we measured miR-320 levels in MCECs upon treated with myocyte-derived exosomes for 1h, and observed that addition of ExoGK caused 10-fold increase of miR-320 in MCECs, compared to ExoCtl treatment. Furthermore, we confirmed that overexpression of miR-320 in MCECs by Ad.miR-320 infection significantly reduced the protein levels of IGF1/IGFR1 and ETS2 (pro-angiogenic factors), leading to inhibition of angiogenesis.
Conclusions: These results indicate that diabetic cardiomyocytes inhibit angiogenesis through exosomal transferring miR-320 into endothelial cells. Our study provides novel mechanism underlying diabetes mellitus-induced myocardial vascular deficiency which may be caused by secretion of anti-angiogenic exosomes from diabetic cardiomyocyes.
- © 2013 by American Heart Association, Inc.