90-OR: Inhibition of miRNA-200b Rescues Diabetes-Impaired Angiogenesis

Impaired angiogenic responses to ischemia characterize the vascular complications associated with diabetes. Diabetic foot ulcers in the presence of ischemia are associated with the most severe outcomes, including a higher rate of mortality and lower probability of healing. Specific micro-RNAs (miRNAs) such as miRNA-200b have been shown to negatively regulate angiogenesis in ischemia. Therefore, we sought to investigate miRNA-200b as a target and biomarker of diabetes-impaired angiogenesis. To assess the importance of miRNA-200b in diabetes-impaired angiogenesis, we transfected endothelial cells with anti-miRNA-200b or anti-miRNA-Neg then performed a functional tubulogenesis assay under high glucose and hypoxic conditions. High glucose impaired tubule formation by 23.6% in response to hypoxia when compared to controls (51.9±15.4 vs. 39.7±23.2, P<0.005), this decrease was prevented by anti-miRNA-200b treatment. Furthermore, in an in vivo hind-limb ischemia model, diabetic mice (n=8-11/group) were injected intramuscularly with anti-miRNA-200b or anti-miRNA-Neg at the time of hind-limb ischemia surgery. Diabetes impaired blood flow reperfusion was assessed by laser Doppler perfusion imaging (LDPI) in anti-miRNA-Neg control mice (LDPI: 0.27), and this was rescued by inhibition of miRNA-200b to nondiabetic levels (LDPI: 0.41, P<0.05). To assess the utility of miRNA-200b as a biomarker of delayed healing, plasma miRNA-200b was measured in a rodent excisional wound model. When compared to controls, diabetes elevated plasma miRNA-200b in both unwounded and wounded animals, suggesting a diabetes related change. Whether this change is seen in humans remains to be investigated.

In conclusion, this study has identified that miRNA-200b is a potential target of diabetes-impaired angiogenesis as shown in this preclinical model of predominant ischemia in a diabetes setting.