Abstract 20121: MicroRNA 27b Rescues Impaired Endothelial Progenitor Cell Angiogenesis and Accelerates Wound Healing via Suppressing Thrombosponding-1 in Type 2 Diabetes
Introduction: EPCs play a key role in angiogenesis, which is impaired in diabetes. MiR-27b promotes angiogenesis in endothelial cells, but its role on EPC angiogenesis in diabetes is unknown. We hypothesized that the mir-27b rescues impaired EPC angiogenesis via suppressing anti-angiogenic thrombospondin-1 (TSP-1) in diabetes.
Methods: Bone marrow-derived EPCs were cultured from adult male (C57BLKS/J, 9 weeks) type 2 diabetic db/db and their normal littermates db/+ mice. MiR-27b and TSP-1 were measured by real-time PCR. Secreted TSP-1 was determined by Western blot. EPC-induced angiogenesis was evaluated by Matrigel tube formation. In vivo wound healing and wound perfusion (Laser Doppler) were dynamically monitored on full thickness excisional wounds, with or without topical EPC therapy.
Results: Mir27b in EPCs was down by >66% in db/db vs. db/+ mice (n=4, p<.05). TSP-1 mRNA and protein were significantly higher in EPCs from db/db vs. db/+ mice (mRNA, 130.1% protein, 127.4%, both n=4, p<.05), which were suppressed upon mir-27b mimic transfection (mRNA by 75% protein by 69%, n=4–6, p<.01). EPC-induced angiogenesis was decreased by >70% in db/db vs. db/+ mice (n=4, p<.05), which was rescued upon mir-27b mimic transfection or silencing TSP-1 expression by its siRNA (both n=4, p<.05). Furthermore, inhibition of mir-27b in normal EPCs increased their TSP-1 protein by 117.5% (n=6, p<.05) and impaired their angiogenesis by 81.5% (n=4, p<.01), both were reversed by TSP-1 siRNA knockdown (n=4, p<.05). Finally, Wound closure was markedly delayed in db/db vs. db/+ mice, accompanied by impaired wound perfusion (both n=4, p<.05). Cell therapy of diabetic EPCs with mir-27b mimic transfection significantly accelerated diabetic wound healing (n=4, p<.05 vs. diabetic EPCs along), with a concomitant augmentation of in vivo wound angiogenesis (n=4, p<.05). Normal EPCs with mir-27b inhibition failed to improve diabetic wound closure or perfusion, which was partly rescued by simultaneously silencing TSP-1 (n=4, p<.05 vs. normal EPCs along). Local inhibition of mir-27b delayed normal healing (n=4, p<.05 vs. db/+ mice).
Conclusions: MiroRNA-27b rescues impaired EPC angiogenesis and accelerates wound healing in type 2 diabetic mice via suppressing TSP-1 expression.
- © 2010 by American Heart Association, Inc.