Long non-coding RNA GAS5 regulates macrophage polarization and diabetic wound healing

A central feature of diabetic (Db) wounds is the persistence of chronic inflammation, which is partly due to the prolonged presence of proinflammatory (M1) macrophages. Using in vivo and in vitro analyses, we have tested the hypothesis that long noncoding RNA GAS5 is dysregulated in Db wounds. We have assessed the contribution of GAS5 to the M1 macrophage phenotype, as well as the functional consequences of knocking down its expression. We found that expression of GAS5 is increased significantly in Db wounds and in cells isolated from Db wounds. Hyperglycemia induced GAS5 expression in macrophages in vitro. Overexpression of GAS5 in vitro promoted macrophage polarization toward an M1 phenotype by upregulating signal transducer and activator of transcription 1. Of most significance in our judgment, GAS5 loss-of-function enhanced Db wound healing. These data indicate that the relative level of long noncoding RNA GAS5 in wounds plays a key role in the wound healing response. Reductions in the levels of GAS5 in wounds appeared to enhance healing by promoting transition of M1 macrophages to M2 macrophages. Thus, our results suggest that targeting long noncoding RNA GAS5 may provide a therapeutic intervention for correcting impaired Db wound healing.