Deregulation of microRNA-503 Contributes to Diabetes Mellitus–Induced Impairment of Endothelial Function and Reparative Angiogenesis After Limb Ischemia

Abstract

Background-Diabetes mellitus impairs endothelial cell (EC) function and postischemic reparative neovascularization by molecular mechanisms that are not fully understood. microRNAs negatively regulate the expression of target genes mainly by interaction in their 3Ј untranslated region. Methods and Results-We found that microRNA-503 (miR-503) expression in ECs is upregulated in culture conditions mimicking diabetes mellitus (high D-glucose) and ischemia-associated starvation (low growth factors). Under normal culture conditions, lentivirus-mediated miR-503-forced expression inhibited EC proliferation, migration, and network formation on Matrigel (comparisons versus lentivirus.GFP control). Conversely, blocking miR-503 activity by either adenovirus-mediated transfer of a miR-503 decoy (Ad.decoymiR-503) or by antimiR-503 (antisense oligonucleotide) improved the functional capacities of ECs cultured under high D-glucose/low growth factors. We identified CCNE1 and cdc25A as direct miR-503 targets which are downregulated by high glucose/low growth factors in ECs. Next, we obtained evidence that miR-503 expression is increased in ischemic limb muscles of streptozotocin-diabetic mice and in ECs enriched from these muscles. Moreover, Ad.decoymiR-503 delivery to the ischemic adductor of diabetic mice corrected diabetes mellitus-induced impairment of postischemic angiogenesis and blood flow recovery. We finally investigated miR-503 and target gene expression in muscular specimens from the amputated ischemic legs of diabetic patients. As controls, calf biopsies of nondiabetic and nonischemic patients undergoing saphenous vein stripping were used. In diabetic muscles, miR-503 expression was remarkably higher, and it inversely correlated with cdc25 protein expression. Plasma miR-503 levels were also elevated in the diabetic individuals. Conclusions-Our Editorial see p 236 Clinical Perspective on p 291Because of their incapacity to regulate glucose influx, endothelial cells (ECs) represent an important target for diabetes mellitus-induced damage. In particular, it is well established that ECs cultured in high glucose show delayed replication, 3,4 abnormal cell cycling, 5 and increased apoptosis. 6 Progression through the cell cycle is a tightly regulated process that includes multiple checkpoints. An orderly ex- The present study is the first to provide evidence for a role of miRNAs in diabetes mellitus-induced endothelial defects contributing to impaired postischemic angiogenesis. In fact, here we show that in vitro culture conditions mimicking diabetes mellitus and ischemia upregulate miR-503 in ECs and that, in vivo, diabetes mellitus increases miR-503 expression in ECs from ischemic limb muscles. We also show that increased miR-503 is responsible for repressed cdc25A and CCNE1 expression in ECs cultured under conditions mimicking diabetes mellitus and ischemia. Moreover, miR-503-forced expression inhibited EC proliferation, migration, and network formation on Matrigel and it additionally reduced vascular smooth muscle ce...

Involvement of miRNAs in ovarian follicular and luteal development

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“…As opposed to this, lentiviral-mediated expression of miR-503 in endothelial cells inhibited cell proliferation and migration. Expression of this microRNA was found to be upregulated in vascular endothelial cells growing in culture conditions mimicking diabetes mellitus (high glucose) and ischemia-associated starvation (low growth factors) (Caporali et al, 2011). These observations make miR-503 as a possible therapeutic target in diabetic patients with critical limb ischemia.…”

“…In contrast, adenovirus-mediated overexpression of miR-98 in cardiomyocytes reduced cell size both at baseline and in response to angiotensin II suggesting for a protective role of this microRNA against angiotensin II-induced cardiac hypertrophy (Yang et al, 2011b). Caporali et al (2011) used an adenoviral vector to transfer a miR-503 decoy to the ischemic adductor of diabetic mice. The delivery of a miR-503 decoy corrected diabetes mellitus-induced impairment of post-ischemic angiogenesis and blood flow recovery.…”

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