Beschreibung:
<jats:p>MicroRNAs (miRNAs/miRs) stably circulate in blood and show biomarker potential under various pathological conditions. Additionally, miRNAs may exert paracrine effect upon cellular uptake.</jats:p>
<jats:p>This study profiles plasma miRNAs of diabetic patients and investigates the paracrine mechanism of miRNA mediated wound repair.</jats:p>
<jats:p>Plasma miRNAs and pro-inflammatory cytokines were profiled in type-2 diabetic patients with or without chronic wounds. Selected miRNA candidates were further validated in plasma samples obtained from controls (n=23), patients with PAD and chronic wound (PAD+W, n=27) or PAD alone (n=11) vs. that of 20 healthy controls by qRT-PCR. Inflammation mediated miRNA secretion and paracrine effects of released miRNAs on cellular functions were investigated in human endothelial or dermal cells respectively.</jats:p>
<jats:p>Differential levels of the circulating miRNAs in diabetic PAD+W patients were revealed in miRNA array profiling. Among 41 miRNA candidates, miR-191 levels significantly increased in PAD+W patients compared to diabetic controls, whereas lower levels were observed in diabetic vs. healthy controls. Circulating CRP and cytokine levels were also high in PAD+W patients compared to diabetic controls. miR-191 significantly correlated with CRP in diabetic patients.</jats:p>
<jats:p>Cytokine stimulation enhanced miR-191 secretion into culture supernatant from vascular endothelial cells. Moreover, co-culture assays maintained under pro-inflammatory stress demonstrated increased miR-191 levels in recipient dermal fibroblast cells when indirectly cultured with miRNA releasing endothelial cells compared to fibroblasts cultured alone. Luciferase reporter confirmed miR-191 binding to the 3’UTR of the ZO-1 transcript. miR-191 modulation in dermal fibroblasts inversely regulated ZO-1 expression and influenced scratch wound closure whereas in diabetic dermal microvascular endothelial cells, miR-191 overexpression compromised both tube formation and wound closure.</jats:p>
<jats:p>Circulating miRNA patterns are influenced by underlying inflammation associated with chronic wounds in type-2 diabetic patients and miR-191 modulates essential cellular functions in a paracrine manner by targeting ZO-1 during wound healing.</jats:p>