Background Wound management of diabetic foot ulcers (DFUs) is a complex and challenging task, and existing strategies fail to meet clinical needs. Therefore, it is important to develop novel drug candidates and discover new therapeutic targets. However, reports on peptides as molecular probes for resolving issues related to DFUs remain rare. This study utilized peptide RL-QN15 as an exogenous molecular probe to investigate the underlying mechanism of endogenous non-coding RNA in DFU wound healing. The aim was to generate novel insights for the clinical management of DFUs and identify potential drug targets. Methods We investigated the wound-healing efficiency of peptide RL-QN15 under diabetic conditions using in vitro and in vivo experimental models. RNA sequencing, in vitro transfection, quantitative real-time polymerase chain reaction, western blotting, dual luciferase reporter gene detection, in vitro cell scratches, and cell proliferation and migration assays were performed to explore the potential mechanism underlying the promoting effects of RL-QN15 on DFU repair. Results Peptide RL-QN15 enhanced the migration and proliferation of human immortalized keratinocytes (HaCaT cells) in a high-glucose environment and accelerated wound healing in a DFU rat model. Based on results from RNA sequencing, we defined a new microRNA (miR-4482-3p) related to the promotion of wound healing. The bioactivity of miR-4482-3p was verified by inhibiting and overexpressing miR-4482-3p. Inhibition of miR-4482-3p enhanced the migration and proliferation ability of HaCaT cells as well as the expression of vascular endothelial growth factor B (VEGFB). RL-QN15 also promoted the migration and proliferation ability of HaCaT cells, and VEGFB expression was mediated via inhibition of miR-4482-3p expression by the p38 mitogen-activated protein kinase (p38MAPK) and smad3 signaling pathways. Conclusions RL-QN15 is an effective molecule for the treatment of DFUs, with the underlying mechanism related to the inhibition of miR-4482-3p expression via the p38MAPK and smad3 signaling pathways, ultimately promoting re-epithelialization, angiogenesis and wound healing. This study provides a theoretical basis for the clinical application of RL-QN15 as a molecular probe in promoting DFU wound healing.

中文翻译：

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肽 RL-QN15 通过 p38 丝裂原激活蛋白激酶和 smad3/miR-4482-3p/血管内皮生长因子 B 轴促进糖尿病足溃疡的伤口愈合

背景 糖尿病足溃疡（DFU）的伤口处理是一项复杂且具有挑战性的任务，现有策略无法满足临床需求。因此，开发新的候选药物并发现新的治疗靶点非常重要。然而，关于肽作为分子探针解决 DFU 相关问题的报道仍然很少。本研究利用肽RL-QN15作为外源性分子探针，研究内源性非编码RNA在DFU伤口愈合中的潜在机制。目的是为 DFU 的临床管理提供新的见解并确定潜在的药物靶点。方法 我们使用体外和体内实验模型研究了糖尿病条件下肽 RL-QN15 的伤口愈合效率。通过RNA测序、体外转染、实时定量聚合酶链式反应、蛋白质印迹、双荧光素酶报告基因检测、体外细胞划痕以及细胞增殖和迁移实验，探讨RL-QN15促进作用的潜在机制。关于DFU修复。结果 在 DFU 大鼠模型中，肽 RL-QN15 增强了人永生化角质形成细胞（HaCaT 细胞）在高葡萄糖环境中的迁移和增殖，并加速了伤口愈合。根据RNA测序的结果，我们定义了一种与促进伤口愈合相关的新的microRNA（miR-4482-3p）。通过抑制和过表达 miR-4482-3p 来验证 miR-4482-3p 的生物活性。抑制 miR-4482-3p 增强 HaCaT 细胞的迁移和增殖能力以及血管内皮生长因子 B (VEGFB) 的表达。RL-QN15 还促进 HaCaT 细胞的迁移和增殖能力，并且 VEGFB 表达是通过 p38 丝裂原激活蛋白激酶 (p38MAPK) 和 smad3 信号通路抑制 miR-4482-3p 表达来介导的。结论 RL-QN15是治疗DFU的有效分子，其潜在机制与通过p38MAPK和smad3信号通路抑制miR-4482-3p表达，最终促进上皮再形成、血管生成和伤口愈合有关。本研究为RL-QN15作为分子探针促进DFU创面愈合的临床应用提供理论依据。