Impaired angiogenesis in diabetic critical limb ischemia is mediated by a miR-130b-INHBA signaling axis.

Patients with peripheral artery disease (PAD) and diabetes constitute a high risk population for development of critical limb ischemia (CLI) and amputation, although the underlying mechanisms remain poorly understood. Comparison of dysregulated microRNAs from diabetic human subjects with PAD and diabetic mice with limb ischemia revealed the conserved microRNA, miR-130b-3p. In vitro angiogenic assays demonstrated miR-130b rapidly promoted proliferation, migration, and sprouting in endothelial cells (ECs), whereas miR-130b inhibition exerted anti-angiogenic effects. Local delivery of miR-130b mimics into ischemic muscles of diabetic mice (db/db) following femoral artery ligation (FAL) promoted revascularization by increasing angiogenesis and markedly improved limb necrosis and amputation. RNA-sequencing, and gene set enrichment analysis from miR-130b overexpressing ECs revealed the BMP / TGF-b signaling pathway as one of the top dysregulated pathways. Accordingly, overlapping downregulated transcripts from RNA-seq and miRNA prediction algorithms identified that miR-130b directly targeted and repressed the TGF-b superfamily member inhibin-b-A (INHBA). miR-130b overexpression or siRNA-mediated knockdown of INHBA induced IL-8 expression, a potent angiogenic chemokine. Lastly, ectopic delivery of silencer RNAs (siRNA) targeting Inhba in db/db ischemic muscles following FAL improved revascularization and limb necrosis, recapitulating the phenotype of miR-130b delivery. Taken together, a miR-130b-INHBA signaling axis may provide therapeutic targets for patients with PAD and diabetes at risk of developing CLI.