From:  Emerging targets and gene-based therapeutics in diabetic foot ulcer: a comprehensive review

 MicroRNA as a therapeutic target to promote wound healing in diabetic foot ulcers (DFUs).

miRNAModelApproachResults
Cell proliferation, migration, function, and cytoskeleton
miR-193b-3p [138]Genomic analysis of DFU tissue samples (n = 15 per group), in vitro keratinocyte (HaCaT) migration assays, organotypic 3D human skin wound models, and in vivo mouse wound healing model (n = 3 per group)miRNA expression profiling, functional gain and loss of function assays, migration analyses, RhoA activity assessment, bioinformatic target prediction, and luciferase reporter validation to determine the mechanistic role of miR193b-3p and its regulation of KRASmiR-193b-3p was found to be upregulated in DFUs, where it inhibited keratinocyte migration and reepithelialization while directly targeting KRAS and other oncogenic pathways. Contributing to impaired wound healing and reduced malignant transformation.
miR-13474 [139]Exosomes secreted by HucMSCs
DFU SD rats (n = 6 per group) received HucMSC exosomes
RNA sequencing analysis of tissues
Blocking miR-13474 in HucMSC-derived exosomesmiR-13474 was significantly differentially expressed between the wound area and the wound edge area.
miR-13474 targets the CPEB2/TWIST1 axis to improve the impaired function of skin cells
miR-21-5p [140]In vitro studiesEVs were isolated from HucMSCsmiR-21-5p were overexpression in EVs.
miR-21-5p inhibits KLF6 and promotes proliferation and migration of HSFs.
Inflammation
miR-15b-5p [141]Human (14 DFU and 12 control) and swine DFU model (n = 2 in each group)Transcriptome analyses of DFU tissueS. aureus-triggered miR-15b-5p induction suppresses inflammation and DNA repair-related genes IKBKB and WEE1.
miR-221-3p [142]Mouse DFU model (n = 6–10 in each group) and human keratinocytes (HaCaT) exposed to high levels of glucosemiR-211-3p levels increased, and the gene was knocked out. Measured inflammation and wound healingmiR-221-3p reduces inflammation and improves wound healing by suppressing DYRK1A, which decreases STAT3 activation and decreases inflammatory cytokine production.
ECM remodeling
miR-29b [143]32 patients with DFU (18 males and 14 females, aged 57.03 ± 8.23 years)
Cerium dioxide nanoparticles-plasmid complexes
Diabetic mouse model (n = 6 per group)
Microarray-based analysis in human samples followed by in-vtro and in-vivo analysisDFU ulcerative edge in mice showed high expression of lncRNA H19 and FBN1 and low expression of miR-29b.
lncRNA H19 and miR-29b promote wound healing involving FBN1.
Angiogenesis
miR-23c [144]40 subjects with normal glucose tolerance (n  =  10), T2DM patients free from other complications, T2DM subjects with uninfected DFU, and T2DM subjects with infected DFU (n  =  10 each)hsa-miR-23a, hsa-miR-23b, hsa-miR-23c, and angiogenic factors such as SDF-1α, HIF-1α, VEGF, and eNOS were investigated in peripheral blood mononuclear cells and tissue biopsy samples using qPCRSDF-1α has a significant inverse association with miR-23c.
miR-23c functions as a new regulator to inhibit angiogenesis by targeting SDF-1α..
miR-155 [145]Human DFU patients’ wound tissue
control group (n = 36) and the PRF group (n = 24)
PRF treatment; miR-155 expression analysisPRF treatment suppressed miR-155, increased HIF-1α /VEGF, and vascular density, as well as accelerated wound healing.
miR-27b [146]Human chronic DFU (n = 10) tissue vs. acute DFU tissue (n = 12) and hyperglycemic endothelial cellsmiR-27b and angiogenic marker expression analysis; knockdown of miR-27b and Nrf2 activation studies; miR-27b and Nrf2 pathway expression analysismiR-27b levels were lower in chronic DFU and showed a correlation with Nrf2. Reducing miR-27b impaired Nrf2 signaling and angiogenesis. Activating Nrf2 restored miR-27b levels and gene expression.
miR-146a-5p (inflammation)
and miR-29a-3p (angiogenesis) [147]
HaCaT cellsHaCaT cells were transfected with miR-146a-5p or miR-29a-3p inhibitors individually or in combination, following stimulation with TNF-αmiR-146a-5p and miR-29a-3p inhibitor supplementation to diabetic wounds reduced the wound size on days 8 and 9 but did not lead to complete healing by day 10.

DFU: diabetic foot ulcer; ECM: extracellular matrix; eNOS: endothelial nitric oxide synthase; FBN1: fibrillin 1; HIF-1α: hypoxia inducible factor 1α; HSFs: human skin fibroblasts; HucMSCs: human umbilical cord mesenchymal stem cells; IKBKB: inhibitor of nuclear factor kappa-B kinase subunit beta; KLF6: Kruppel-like factor 6; miR: microRNA; Nrf2: nuclear factor erythroid 2-related factor 2; PRF: platelet-rich fibrin; SDF-1α: stromal-derived factor-1α; TNF: tumor necrosis factor; VEGF: vascular endothelial growth factor.