Department of General Surgery, The Second Xiangya Hospital, Central South University, Changsha, China.
Department of Burn and Plastic Surgery, The Second Xiangya Hospital, Central South University, Changsha, China.
Neuroimmunomodulation. 2019;26(5):239-249. doi: 10.1159/000503087. Epub 2019 Nov 8.
As a complication of diabetes mellitus (DM), one of the leading causes for death and disability for DM patients is diabetic foot ulcers (DFUs). Epithelial to mesenchymal transition (EMT) plays a critical role in wound healing of DFUs. miR-203 is specifically enriched in keratinocytes and has been shown to target interleukin 8 (IL-8), which acts as an activator for the EMT process. In this study, we explored the interaction between miR-203 and IL-8 in DFU rat models and human keratinocyte cells, underlying the mechanism of miR-203's function in DFUs progression.
DFU rat models were used to test gene expression in DFU progression. Diabetic keratinocyte cell lines were used to validate in vitro. Wound healing and Transwell assays were applied to evaluate cell migration and invasion abilities. The EMT process was estimated by testing expression of E-cadherin, Vimentin and Slug. The interaction between miR-203 and IL-8 was determined by Luciferase assay.
Our results demonstrated that the wound-healing process had been slowed in DFUs, and the advanced glycation end products (AGEs) and the receptor for advanced glycation end products (RAGEs) in wound tissue were of a higher expression than those in normal rat. miR-203 was increased in skin tissues from DFU rat models, while IL-8 was decreased. Through knock-down of miR-203 in AGE-treated keratinocyte cells, it had been shown that the downregulation of miR-203 could promote cell proliferation and migration, and facilitate the EMT process. Meanwhile, Luciferase assay proved that miR-203 could directly target and inhibit IL-8. The repression of IL-8 could rescue the outcomes brought about by miR-203 inhibition.
The upregulation of miR-203 in DFU tissues impaired wound healing by the repress EMT process. Specific knock-down of miR-203 could promote wound healing through the reactivation of its target gene IL-8 and the downstream IL-8/AKT pathway.
糖尿病足溃疡（DFU）是糖尿病患者死亡和致残的主要原因之一，是糖尿病（DM）的一种并发症。上皮间质转化（EMT）在 DFU 的伤口愈合中起着关键作用。miR-203 特异性富集于角质形成细胞，并已被证明靶向白细胞介素 8（IL-8），后者作为 EMT 过程的激活剂。在这项研究中，我们探讨了 miR-203 与 DFU 大鼠模型和人角质形成细胞中的 IL-8 之间的相互作用，揭示了 miR-203 在 DFU 进展中的作用机制。
使用 DFU 大鼠模型检测 DFU 进展过程中的基因表达。使用糖尿病角质形成细胞系进行体外验证。应用划痕愈合和 Transwell 实验评估细胞迁移和侵袭能力。通过检测 E-钙黏蛋白、波形蛋白和 Slug 的表达来评估 EMT 过程。通过荧光素酶测定确定 miR-203 和 IL-8 之间的相互作用。
我们的结果表明，DFUs 中的伤口愈合过程已经减慢，伤口组织中的晚期糖基化终产物（AGEs）和晚期糖基化终产物受体（RAGEs）的表达高于正常大鼠。DFU 大鼠模型皮肤组织中 miR-203 增加，而 IL-8 减少。通过在 AGE 处理的角质形成细胞中敲低 miR-203，已经表明 miR-203 的下调可以促进细胞增殖和迁移，并促进 EMT 过程。同时，荧光素酶测定证明 miR-203 可以直接靶向并抑制 IL-8。IL-8 的抑制可以挽救 miR-203 抑制带来的结果。
DFU 组织中 miR-203 的上调通过抑制 EMT 过程损害伤口愈合。miR-203 的特异性敲低可以通过重新激活其靶基因 IL-8 及其下游 IL-8/AKT 通路来促进伤口愈合。
