Decreased expression of miR-204-3p in peripheral blood and wound margin tissue associated with the onset and poor wound healing of diabetic foot ulcers

Protective Effect and Molecular Mechanism of Mesenchymal Stem Cell-Derived Extracellular Vesicles in Diabetic Foot Ulcers

This study explores the protective mechanism of mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) in diabetic foot ulcer (DFU). Human umbilical cord MSCs (HucMSCs) were identified via osteogenesis and adipogenic differentiation, as well as flow cytometry. EVs were isolated from HucMSCs and characterized using transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. Fluorescence microscopy revealed the uptake of PKH67-labeled EVs and Cy3-labeled microRNA-21-5p (miR-21-5p) by human skin fibroblasts (HSFs). EVs were cocultured with HSFs, and cell proliferation and migration were assessed using Cell Counting Kit-8, colony formation, scratch, and Transwell assays. miR-21-5p overexpression in EVs was evaluated for its role in promoting HSF functions. The expression levels of miR-21-5p, Krüppel-like factor 6 (KLF6), α-smooth muscle actin, and collagen type I alpha 1 chain were analyzed via quantitative real-time PCR and Western blotting. The interaction between miR-21-5p and KLF6 was confirmed through a dual-luciferase reporter gene assay. HucMSC-derived EVs enhanced the proliferation and migration of HSFs under high glucose by delivering miR-21-5p, which targeted and inhibited KLF6. Overexpression of KLF6 counteracted the pro-proliferative and migratory effects of EVs carrying miR-21-5p. Overall, these findings suggest that HucMSC-EVs promote HSF proliferation and migration by downregulating KLF6 via miR-21-5p delivery, offering a potential therapeutic strategy for DFU.

Enhancing diabetic foot ulcer healing: Impact of the regulation of the FUS and ILF2 RNA‑binding proteins through negative pressure wound therapy

Diabetic foot ulcer (DFU) is a destructive complication of diabetes. Negative pressure wound therapy (NPWT) promotes DFU wound healing through an undetermined mechanism. In the present study, RNA sequencing was performed on wound granulation tissue from 3 patients with DFU before and after 1 week of NPWT. The fused in sarcoma (FUS) and interleukin enhancer binding factor 2 (ILF2) encoding RNA‑binding proteins (RBPs) were screened from the sequencing data, and wound tissue samples from 24 patients with DFU were validated and analyzed before and after receiving NPWT by reverse transcription‑quantitative PCR, western blotting and immunohistochemistry. In addition, in vitro and in vivo experiments were conducted to determine the effect of the expression of FUS and ILF2 on the function of human epidermal keratinocyte cells (HaCaT cells) and the healing of diabetic skin wounds. The results indicated that NPWT induced the upregulation of 101 genes and the downregulation of 98 genes in DFU wound granulation tissue. After NPWT, the expression of FUS and ILF2 was significantly upregulated (P<0.05). Pearson's correlation coefficient showed that the changes in FUS and ILF2 before and after NPWT were negatively correlated with changes in white blood cells, the neutrophil percentage, C‑reactive protein, tumor necrosis factor‑α, reactive oxygen species, lipid peroxides, matrix metalloproteinase (MMP) 2 and MMP9 (P<0.05), but positively correlated with the anti‑inflammatory factor, IL‑4 (P<0.01). There was also a positive correlation (P<0.05) with the 4‑week ulcer healing rate. Additionally, the knockdown of FUS and ILF2 expression inhibited the proliferation and migration of HaCaT cells, while increasing cell apoptosis. In vivo, the knockdown of FUS and ILF2 significantly reduced the rate of skin wound healing in diabetic mice. The results of the present study therefore provide new insights into the mechanism by which NPWT promotes DFU wound healing. In conclusion, the RBPs, FUS and ILF2, promoted DFU wound healing by regulating the function of keratinocytes and reducing the inflammatory response and oxidative stress.

MicroRNA Signature in an In Vitro Keratinocyte Model of Diabetic Wound Healing

Treating diabetic wounds effectively remains a significant clinical challenge. Emerging studies suggest that microRNAs (miRNAs) play crucial roles in various physiological and pathological processes and hold promise as therapeutic tools. This study investigates the miRNA expression profile in keratinocytes using a cell model of diabetic wounds. Microarray analysis revealed that 43 miRNAs from wounded keratinocytes incubated under diabetic conditions (high glucose/hypoxia) exhibited a two-fold change in expression compared to those incubated under normal conditions (low glucose/normoxia). Quantitative RT-PCR confirmed significant differences in the expression of eight miRNAs, with miR-3138 and miR-3679-5p being further analyzed for their roles in keratinocyte migration. Transfection with a miR-3138 mimic and a miR-3679-5p inhibitor indicated that upregulation of miR-3138 and downregulation of miR-3679-5p enhance keratinocyte migration in both normal and diabetic wounds. Pathway and gene ontology (GO) analyses identified potential pathways and functional annotations associated with miR-3138 and miR-3679-5p in diabetic wound healing. Potential human gene targets of miR-3138 and miR-3679-5p were predicted using a three-way comparison of the TargetScan, miRDB, and DIANA databases. This study elucidates the miRNA expression signature of human keratinocytes in a diabetes-like environment, providing deeper insights into the pathogenesis of diabetic wounds.

Nuclear miR-204-3p mitigates metabolic dysfunction-associated steatotic liver disease in mice

BACKGROUND & AIMS

Accumulating evidence has indicated the presence of mature microRNAs (miR) in the nucleus, but their effects on steatohepatitis remain elusive. We have previously demonstrated that the intranuclear miR-204-3p in macrophages protects against atherosclerosis, which shares multiple risk factors with metabolic dysfunction-associated steatotic liver disease (MASLD). Herein, we aimed to explore the functional significance of miR-204-3p in steatohepatitis.

METHODS

miR-204-3p levels and subcellular localization were assessed in the livers and peripheral blood mononuclear cells of patients with MASLD. Wild-type mice fed high-fat or methionine- and choline-deficient diets were injected with an adeno-associated virus system containing miR-204-3p to determine the effect of miR-204-3p on steatohepatitis. Co-culture systems were applied to investigate the crosstalk between macrophages and hepatocytes or hepatic stellate cells (HSCs). Multiple high-throughput epigenomic sequencings were performed to explore miR-204-3p targets.

RESULTS

miR-204-3p expression decreased in livers and macrophages in mice and patients with fatty liver. In patients with MASLD, miR-204-3p levels in peripheral blood mononuclear cells were inversely related to the severity of hepatic inflammation and damage. Macrophage-specific miR-204-3p overexpression reduced steatohepatitis in high-fat or methionine- and choline-deficient diet-fed mice. miR-204-3p-overexpressing macrophages inhibited TLR4/JNK signaling and pro-inflammatory cytokine release, thereby limiting fat deposition and inflammation in hepatocytes and fibrogenic activation in HSCs. Epigenomic profiling identified miR-204-3p as a specific regulator of ULK1 expression. ULK1 transcription and VPS34 complex activation by intranuclear miR-204-3p improved autophagic flux, promoting the anti-inflammatory effects of miR-204-3p in macrophages.

CONCLUSIONS

miR-204-3p inhibits macrophage inflammation, coordinating macrophage actions on hepatocytes and HSCs to ameliorate steatohepatitis. Macrophage miR-204-3p may be a therapeutic target for MASLD.

IMPACT AND IMPLICATIONS

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a chronic inflammatory disease ranging from simple steatosis to steatohepatitis. However, the molecular mechanisms underlying the progression of MASLD remain incompletely understood. Here, we demonstrate that miR-204-3p levels in circulating peripheral blood mononuclear cells are negatively correlated with disease severity in patients with MASLD. Nuclear miR-204-3p activates ULK1 transcription and improves autophagic flux, limiting macrophage activation and hepatic steatosis. Our study provides a novel understanding of the mechanism of macrophage autophagy and inflammation in steatohepatitis and suggests that miR-204-3p may act as a potential therapeutic target for MASLD.

Effect and mechanism of microRNAs on various diabetic wound local cells

The difficulty of wound healing in diabetes mellitus has long been regarded as a thorny problem in the medical field. One of the important reasons is the abnormal function of wound-related cells. A large number of recent studies have shown that microRNA (miR), a noncoding RNA that exists in eukaryotic cells, is closely linked to the functions of various cells in diabetic wound, and ultimately affects the healing of wound. This paper establishes for the first time the connection between miR and wound healing from the cellular perspective and summarizes the effects of various miRs on one or more kinds of wound cells, including their targets and related mechanisms. The abnormal expression of miRs in the wound has certain value for the early diagnosis of diabetic wounds. Moreover, it seems that correcting miRs that are abnormal expressed in the wound or artificially adding miRs that can promote wound healing has an essential therapeutic value.

Negative pressure wound therapy promotes wound healing of diabetic foot ulcers by up-regulating PRDX2 in wound margin tissue

To understand the changes in the peroxiredoxin-2 (PRDX2) expression level in the wound margin tissue (T-PRDX2) of patients with diabetic foot ulcer (DFU) before and after negative pressure wound therapy (NPWT). Additionally, the study aimed to explore the association between PRDX2 expression and the treatment outcome of DFUs to provide a new theoretical basis for revealing the mechanism of NPWT promoting the healing of DFUs. Fifty-six type 2 diabetes patients with foot ulcers undergoing NPWT (the DFU group) and 28 patients with chronic lower limb skin ulcers with normal glucose tolerance undergoing NPWT (the skin ulcer control [SUC] group) were included in the study. T-PRDX2 was detected using Western blotting, and the superoxide dismutase (SOD) activity and the malondialdehyde (MDA) and glutathione (GSH) levels were detected using a biochemical method. In addition, in vitro experiments were conducted to determine the effect of PRDX2 expression on normal human dermal fibroblast (NHDF) proliferation, migration, and apoptosis. Before NPWT, the DFU group exhibited a significantly lower T-PRDX2 expression level compared with the SUC group. After one week of NPWT, the T-PRDX2 expression level, SOD activity, and GSH content in the wound margin tissues of the DFU and SUC groups significantly increased compared with the before NPWT levels. Conversely, the inflammatory indicators (white blood cell, neutrophil percentage, C-reactive protein, and procalcitonin) and MDA content were significantly lower than the before NPWT levels. The expression changes of T-PRDX2 before and after NPWT in the DFU and SUC groups were positively correlated with the 4-week wound healing rate. In vitro experiments demonstrated that PRDX2 could alleviate the oxidative stress in NHDFs, thereby promoting their proliferation and migration, while reducing cell apoptosis. NPWT promotes DFU healing by increasing T-PRDX2, and changes in the T-PRDX2 might be associated with the therapeutic effect of NPWT.

The role of programmed cell death in diabetic foot ulcers

Diabetic foot ulcer, is a chronic complication afflicting individuals with diabetes, continue to increase worldwide, immensely burdening society. Programmed cell death, which includes apoptosis, autophagy, ferroptosis, necroptosis and pyroptosis, has been increasingly implicated in the pathogenesis of diabetic foot ulcer. This review is based on an exhaustive examination of the literature on 'programmed cell death' and 'diabetic foot ulcers' via PubMed. The findings revealed that natural bioactive compounds, noncoding RNAs and certain proteins play crucial roles in the healing of diabetic foot ulcers through various forms of programmed cell death, including apoptosis, autophagy, ferroptosis and pyroptosis.

Deciphering The Emerging Role of Programmed Cell Death in Diabetic Wound Healing

Diabetic wounds are characterized by delayed and incomplete healing. As one of the most common complications of diabetes, diabetic wounds can be fatal in some cases. Programmed cell death (PCD) is an active and ordered cell death mode determined by genes, including apoptosis, autophagy, pyroptosis, necroptosis, ferroptosis, and cuproptosis. It is currently believed that PCD plays a crucial role in diabetic wound healing. Diabetic hyperglycemic environments can lead to abnormal PCD in various cells during healing processes, thereby affecting the activity and function of cells and interfering with diabetic wound healing. Therefore, this review focuses on the new roles and mechanisms of PCD in diabetic wound healing. Moreover, the challenges and perspectives related to PCD in diabetic wound healing are presented, which will bring new insights to improve diabetic wound healing.

Adipose-derived stem cell exosome NFIC improves diabetic foot ulcers by regulating miR-204-3p/HIPK2

BACKGROUND

Diabetic foot ulcers (DFU) are a serious complication of diabetes that lead to significant morbidity and mortality. Recent studies reported that exosomes secreted by human adipose tissue-derived mesenchymal stem cells (ADSCs) might alleviate DFU development. However, the molecular mechanism of ADSCs-derived exosomes in DFU is far from being addressed.

METHODS

Human umbilical vein endothelial cells (HUVECs) were induced by high-glucose (HG), which were treated with exosomes derived from nuclear factor I/C (NFIC)-modified ADSCs. MicroRNA-204-3p (miR-204-3p), homeodomain-interacting protein kinase 2 (HIPK2), and NFIC were determined using real-time quantitative polymerase chain reaction. Cell proliferation, apoptosis, migration, and angiogenesis were assessed using cell counting kit-8, 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, wound healing, and tube formation assays. Binding between miR-204-3p and NFIC or HIPK2 was predicted using bioinformatics tools and validated using a dual-luciferase reporter assay. HIPK2, NFIC, CD81, and CD63 protein levels were measured using western blot. Exosomes were identified by a transmission electron microscope and nanoparticle tracking analysis.

RESULTS

miR-204-3p and NFIC were reduced, and HIPK2 was enhanced in DFU patients and HG-treated HUVECs. miR-204-3p overexpression might abolish HG-mediated HUVEC proliferation, apoptosis, migration, and angiogenesis in vitro. Furthermore, HIPK2 acted as a target of miR-204-3p. Meanwhile, NFIC was an upstream transcription factor that might bind to the miR-204-3p promoter and improve its expression. NFIC-exosome from ADSCs might regulate HG-triggered HUVEC injury through miR-204-3p-dependent inhibition of HIPK2.

CONCLUSION

Exosomal NFIC silencing-loaded ADSC sheet modulates miR-204-3p/HIPK2 axis to suppress HG-induced HUVEC proliferation, migration, and angiogenesis, providing a stem cell-based treatment strategy for DFU.

The Epidermal Keratinocyte as a Therapeutic Target for Management of Diabetic Wounds

Diabetes mellitus (DM) is an important cause of chronic wounds and non-traumatic amputation. The prevalence and number of cases of diabetic mellitus are increasing worldwide. Keratinocytes, the outermost layer of the epidermis, play an important role in wound healing. A high glucose environment may disrupt the physiologic functions of keratinocytes, resulting in prolonged inflammation, impaired proliferation, and the migration of keratinocytes and impaired angiogenesis. This review provides an overview of keratinocyte dysfunctions in a high glucose environment. Effective and safe therapeutic approaches for promoting diabetic wound healing can be developed if molecular mechanisms responsible for keratinocyte dysfunction in high glucose environments are elucidated.