MicroRNA-129 and -335 Promote Diabetic Wound Healing by Inhibiting Sp1-Mediated MMP-9 Expression

Abstract

Diabetic wounds are recalcitrant to healing. However, the mechanism causing this dysfunction is not fully understood. High expression of matrix metalloproteinase-9 (MMP-9) is indicative of poor wound healing. In this study, we show that specificity protein-1 (Sp1), a regulator of MMP-9, binds directly to its promoter and enhances its expression. Additionally, we demonstrated that Sp1 is the direct target of two microRNAs (miRNAs), miR-129 and -335, which are significantly downregulated in diabetic skin tissues. In vitro experiments confirmed that miR-129 or -335 overexpression inhibits MMP-9 promoter activity and protein expression by targeting Sp1, whereas the inhibition of these miRNAs has the opposite effect. The beneficial role of miR-129 or miR-335 in diabetic wound healing was confirmed by the topical administration of miRNA agomirs in diabetic animals. This treatment downregulated Sp1-mediated MMP-9 expression, increased keratinocyte migration, and recovered skin thickness and collagen content. The combined treatment with miR-129 and miR-335 induced a synergistic effect on Sp1 repression and MMP-9 downregulation both in vitro and in vivo. This study demonstrates the regulatory mechanism of Sp1-mediated MMP-9 expression in diabetic wound healing and highlights the potential therapeutic benefits of miR-129 and -335 in delayed wound healing in diabetes.

MIR-300 in the imprinted DLK1-DIO3 domain suppresses the migration of bladder cancer by regulating the SP1/MMP9 pathway

“…To further identify the underlying mechanism, a Western blot assay was conducted, and we found that like the SP1 protein, the MMP9 protein was also downregulated after siRNAs were transfected into T24 and UM-UC3 cells (Figure 4(c)). Previous studies showed that SP1, as a transcription factor, could specifically bind to the promoter site of MMP9 and enhance MMP9 expression [29][30][31]. So we conducted a ChIP assay in UM-UC3 cells.…”

Macrophage-derived exosomes accelerate wound healing through their anti-inflammation effects in a diabetic rat model

“…A large amount of inflammatory mediators, such as tumor necrosis factor (TNF)-a and interleukin (IL)-6, secreted by cells were released into the wound site and subsequently prevented the cell proliferation and migration required for diabetic wound healing [5]. Furthermore, over-activation of inflammation increased matrix metalloproteinase (MMP)-9 expression [6,7], which resulted in rapid degradation of native collagen, fibronectin, and elastin, thus delaying the diabetic wound-healing process [8].…”

microRNA-203 Modulates Wound Healing and Scar Formation via Suppressing Hes1 Expression in Epidermal Stem Cells

“…Many studies have identified various miRNAs involved in cell differentiation and skin wound healing [16,17]. One of these important miRNAs is miR-203.…”