microRNA-155 inhibition restores Fibroblast Growth Factor 7 expression in diabetic skin and decreases wound inflammation

Acidic fibroblast growth factor inhibits reactive oxygen species-induced epithelial-mesenchymal transdifferentiation in vascular endothelial cells via the miR-155-5p/SIRT1/Nrf2/HO-1 pathway to promote wound healing in diabetic mice

Background

Diabetic chronic wounds are among the most common and serious complications of diabetes and are associated with significant morbidity and mortality. Endothelial-to-mesenchymal transition (EndMT) is a specific pathological state in which endothelial cells are transformed into mesenchymal cells in response to various stimuli, such as high glucose levels and high oxidative stress. Acidic fibroblast growth factor (aFGF), which is a member of the fibroblast growth factor family, possesses strong antioxidant properties and can promote the differentiation of mesenchymal stem cells into angiogenic cells. Therefore, we investigated the role of aFGF in EndMT in diabetic wounds and analysed the underlying mechanisms.

Methods

A diabetic mouse model was used to verify the effect of aFGF on wound healing, and the effect of aFGF on vascular endothelial cells in a high-glucose environment was examined in vitro. We examined the expression of miR-155-5p in a high-glucose environment and the miR-155 downstream target gene SIRT1 by luciferase reporter assays.

Results

aFGF promoted wound closure and neovascularization in a mouse model of type 2 diabetes. In vitro, aFGF inhibited the production of total and mitochondrial reactive oxygen species (ROS) in vascular endothelial cells and alleviated epithelial-mesenchymal transdifferentiation in a high-glucose environment. Mechanistically, aFGF promoted the expression of SIRT1 and the downstream targets Nrf2 and HO-1 by negatively regulating miR-155-5p, thereby reducing ROS generation.

Conclusions

In conclusion, our results suggest that aFGF inhibits ROS-induced epithelial-mesenchymal transdifferentiation in diabetic vascular endothelial cells via the miR-155-5p/SIRT1/Nrf2/HO-1 axis, thereby promoting wound healing.

mir-182-5p regulates all three phases of inflammation, proliferation, and remodeling during cutaneous wound healing

Wound healing is a highly programmed process, in which any abnormalities result in scar formation. MicroRNAs are potent regulators affecting wound repair and scarification. However, the function of microRNAs in wound healing is not fully understood. Here, we analyzed the expression and function of microRNAs in patients with cutaneous wounds. Cutaneous wound biopsies from patients with either hypertrophic scarring or normal wound repair were collected during inflammation, proliferation, and remodeling phases. Fourteen candidate microRNAs were selected for expression analysis by qRT-PCR. The expression of genes involved in inflammation, angiogenesis, proliferation, and migration were measured using qRT-PCR. Cell cycle and scratch assays were used to explore the proliferation and migration rates. Flow cytometry analysis was employed to examine TGF-β, αSMA and collagen-I expression. Target gene suggestion was performed using Enrichr tool. The results showed that miR-16-5p, miR-152-3p, miR-125b-5p, miR-34c-5p, and miR-182-5p were revealed to be differentially expressed between scarring and non-scarring wounds. Based on the expression patterns obtained, miR-182-5p was selected for functional studies. miR-182-5p induced RELA expression synergistically upon IL-6 induction in keratinocytes and promoted angiogenesis. miR-182-5p prevented keratinocyte migration, while overexpressed TGF-β3 following induction of inflammation. Moreover, miR-182-5p enhanced fibroblast proliferation, migration, differentiation, and collagen-1 expression. FoxO1 and FoxO3 were found to potentially serve as putative gene targets of miR-182-5p. In conclusion, miR-182-5p is differentially expressed between scarring and non-scarring wounds and affect the behavior of cells involved in cutaneous wound healing. Deregulated expression of miR-182-5p adversely affects the proper transition of wound healing phases, resulting in scar formation.

The role of FGF-21 in promoting diabetic wound healing by modulating high glucose-induced inflammation

Background

Wound healing is a complex biological process that can be impaired in individuals with diabetes. Diabetic wounds are a serious complication of diabetes that require promoting diagnosis and effective treatment. FGF-21, a member of the endocrine FGF factors family, has caught the spotlight in the treatment of diabetes for its beneficial effects on accelerating human glucose uptake and fat catabolism. However, the therapeutic efficacy of FGF-21 in promoting diabetic wounds remains unknown. This study aims to evaluate the therapeutic potential of FGF-21 in promoting diabetic wound healing.

Methods

we investigated the effects of FGF-21 on wound healing related-cells under high-glucose conditions using various assays such as CCK8, scratch assay, flow cytometry analysis, endothelial tube-formation assay, and transmission electron microscopy. Furthermore, we used db/db mice to verify the healing-promoting therapeutic effects of FGF-21 on diabetic wounds. We also conducted qRT-PCR, Western blot, and immunofluorescence staining analyses to elucidate the underlying mechanism.

Result

Our results indicate that FGF-21 treatment restored hyperglycemic damage on endothelial cell proliferation, migration, and tube-forming ability. It also reduced endothelial cell death rates under high-glucose conditions. TEM analysis showed that FGF-21 treatment effectively restored mitochondrial damage and morphological changes in endothelial cells caused by glucose. Additionally, qRT-PCR and Western blot analysis indicated that FGF-21 treatment restored inflammatory responses caused by hyperglycemic damage. Animal experiments confirmed these findings, suggesting that FGF-21 may be a promising candidate for the treatment of non-healing diabetic wounds due to its effectiveness in stimulating angiogenesis and anti-inflammatory function.

Conclusion

Our study provides evidence that FGF-21 is an essential regulator of wound-related cells under high-glucose conditions and has the potential to be a novel therapeutic target for accelerating diabetic wound healing.

Epigenetic modification: A novel insight into diabetic wound healing

Wound healing is an intricate and fine regulatory process. In diabetic patients, advanced glycation end products (AGEs), excessive reactive oxygen species (ROS), biofilm formation, persistent inflammation, and angiogenesis regression contribute to delayed wound healing. Epigenetics, the fast-moving science in the 21st century, has been up to date and associated with diabetic wound repair. In this review, we go over the functions of epigenetics in diabetic wound repair in retrospect, covering transcriptional and posttranscriptional regulation. Among these, we found that histone modification is widely involved in inflammation and angiogenesis by affecting macrophages and endothelial cells. DNA methylation is involved in factors regulation in wound repair but also affects the differentiation phenotype of cells in hyperglycemia. In addition, noncodingRNA regulation and RNA modification in diabetic wound repair were also generalized. The future prospects for epigenetic applications are discussed in the end. In conclusion, the study suggests that epigenetics is an integral regulatory mechanism in diabetic wound healing.

Roles of fibroblast growth factors in the treatment of diabetes

Diabetes affects about 422 million people worldwide, causing 1.5 million deaths each year. However, the incidence of diabetes is increasing, including several types of diabetes. Type 1 diabetes (5%-10% of diabetic cases) and type 2 diabetes (90%-95% of diabetic cases) are the main types of diabetes in the clinic. Accumulating evidence shows that the fibroblast growth factor (FGF) family plays important roles in many metabolic disorders, including type 1 and type 2 diabetes. FGF consists of 23 family members (FGF-1-23) in humans. Here, we review current findings of FGFs in the treatment of diabetes and management of diabetic complications. Some FGFs (e.g., FGF-15, FGF-19, and FGF-21) have been broadly investigated in preclinical studies for the diagnosis and treatment of diabetes, and their therapeutic roles in diabetes are currently under investigation in clinical trials. Overall, the roles of FGFs in diabetes and diabetic complications are involved in numerous processes. First, FGF intervention can prevent high-fat diet-induced obesity and insulin resistance and reduce the levels of fasting blood glucose and triglycerides by regulating lipolysis in adipose tissues and hepatic glucose production. Second, modulation of FGF expression can inhibit renal and cardiac fibrosis by regulating the expression of extracellular matrix components, promote diabetic wound healing process and bone repair, and inhibit cancer cell proliferation and migration. Finally, FGFs can regulate the activation of glucose-excited neurons and the expression of thermogenic genes.

Engineered keratin/bFGF hydrogel to promote diabetic wound healing in rats

Keratin materials are promising in wound healing acceleration, however, it is a challenge for the keratin to efficiently therapy the impaired wound healing, such as diabetic foot ulcers. Here, we report a keratin/bFGF hydrogel for skin repair of chronic wounds in diabetic rats based on their characteristics of extracellular matrix and growth factor degradation in diabetic ulcer. Recombinant keratin 31 (K31), the most abundant keratin in human hair, exhibited the highly efficient performances in cell adhesion, proliferation and migration. More importantly, the introduction of bFGF into K31 hydrogel significantly enhances the properties of cell proliferation, wound closure acceleration, angiogenesis and skin appendages regeneration. Furthermore, the combination of K31 and bFGF can promote epithelial-mesenchymal transition by inhibiting the expression of E-cadherin and promoting the expression of vimentin and fibronectin. These findings demonstrate the engineered K31/bFGF hydrogel as a promising therapeutic agent for diabetic wound healing.

A mutual regulatory loop between miR-155 and SOCS1 influences renal inflammation and diabetic kidney disease

Diabetic kidney disease (DKD) is a common microvascular complication of diabetes, a global health issue. Hyperglycemia, in concert with cytokines, activates the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway to induce inflammation and oxidative stress contributing to renal damage. There is evidence of microRNA-155 (miR-155) involvement in diabetes complications, but the underlying mechanisms are unclear. In this study, gain- and loss-of-function experiments were conducted to investigate the interplay between miR-155-5p and suppressor of cytokine signaling 1 (SOCS1) in the regulation of the JAK/STAT pathway during renal inflammation and DKD. In experimental models of mesangial injury and diabetes, miR-155-5p expression correlated inversely with SOCS1 and positively with albuminuria and expression levels of cytokines and prooxidant genes. In renal cells, miR-155-5p mimic downregulated SOCS1 and promoted STAT1/3 activation, cytokine expression, and cell proliferation and migration. Conversely, both miR-155-5p antagonism and SOCS1 overexpression protected cells from inflammation and hyperglycemia damage. In vivo, SOCS1 gene delivery decreased miR-155-5p and kidney injury in diabetic mice. Moreover, therapeutic inhibition of miR-155-5p suppressed STAT1/3 activation and alleviated albuminuria, mesangial damage, and renal expression of inflammatory and fibrotic genes. In conclusion, modulation of the miR-155/SOCS1 axis protects kidneys against diabetic damage, thus highlighting its potential as therapeutic target for DKD.

Mechanism of Yixishu lotion in the treatment of vaginitis based on network pharmacology combined with experimental validation: an experimental research study

Objective

Yixishu lotion (YXSL) originates from the summary of traditional Chinese medicine clinical experience and constantly improves in practice in clinical validation of the exact efficacy of traditional Chinese medicine prescription. To explore the mechanism of YXSL in treating vaginitis and the potential mechanisms based on network pharmacology and experimental verification.

Methods

The active components and drug-related targets of YXSL were retrieved from the TCMSP (Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform) database, and the target was predicted by the UniProt database. Searching for genes related to 'vaginitis' disease in the GeneCards database, a total of 2581 drug targets were obtained. The interaction between proteins (PPI - protein-protein interaction) relationship was obtained by STRING database and visualized by Cytoscape software. Finally, the 'Bioconductor' installation package in R software was used to analyze the GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathways of the target.

Results

In this study, by the method of network pharmacology, the key active components of YXSL were flavonoids such as quercetin, apigenin, kaempferol, luteolin, β-sitosterol; the main core proteins included MAPK14, TP53, FGF2, ESR1, MAPK3, MAPK1, VEGFA, JUN, IL-6, and the KEGG pathway was mainly involved in MAPK pathway, Th17 pathway, Malaria, TNF pathway, and other signaling pathways. Animal experiments showed that the clinical symptoms and vaginal tissue lesions of the YXSL group and the fluconazole group were improved, and the levels of TNF-α (tumor necrosis factor alpha), IL-6 (interleukin-6), MDA (malondialdehyde), SOD (superoxide dismutase), IL-4, and IFN-γ (interferon-γ) in vaginal tissue and serum were better than the model group.

Conclusion

YXSL may achieve its therapeutic effect on vaginitis by reducing the inflammatory response, improving oxidative stress response, and improving body immunity, and it provides a theoretical basis for further research on its pharmacodynamic material basis and mechanism of action.

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.

Accelerated Wound Healing in Diabetic Rat by miRNA-185-5p and Its Anti-Inflammatory Activity

Aim

Addressing both inflammation and epithelialization during the treatment of diabetic foot ulcers is an important step, but current treatment options are limited. MiRNA has important prospects in the treatment of diabetic foot refractory wound ulcers. Previous studies have reported that miR-185-5p reduces hepatic glycogen production and fasting blood glucose levels. We herein hypothesized that miR-185-5p might play an important role in the field of diabetic foot wounds.

Materials and Methods

MiR-185-5p in skin tissue samples from patients with diabetic ulcers and diabetic rats were measured using quantitative real-time PCR (qRT-PCR). The streptozotocin-induced diabetes rat model (male Sprague-Dawley rats) for diabetic wound healing was conducted. The therapeutic potential was observed by subcutaneous injection of miR-185-5p mimic into diabetic rat wounds. The anti-inflammation roles of miR-185-5p on human dermal fibroblast cells were analyzed.

Results

We found that miR-185-5p is significantly downregulated in diabetic skin (people with DFU and diabetic rats) compared to controls. Further, in vitro upregulation of miR-185-5p decreased the inflammatory factors (IL-6, TNF-α) and intercellular adhesion molecule 1 (ICAM-1) of human skin fibroblasts under advanced glycation end products (AGEs). Meanwhile, the increase of miR-185-5p promoted cell migration. Our results also confirmed that the topical increase of miR-185-5p decreases diabetic wound p-nuclear factor-κB (p-NF-κB), ICAM-1, IL-6, TNF-α, and CD68 expression in diabetic wounds. MiR-185-5p overexpression boosted re-epithelization and expedited wound closure of diabetic rats.

Conclusion

MiR-185-5p accelerated wound healing of diabetic rats, reepithelization, and inhibited the inflammation of diabetic wounds in the healing process, a potentially new and valid treatment for refractory diabetic foot ulcers.

Diabetic macrophage small extracellular vesicles-associated miR-503/IGF1R axis regulates endothelial cell function and affects wound healing

Diabetic foot ulcer (DFU) is a break in the skin of the foot caused by diabetes. It is one of the most serious and debilitating complications of diabetes. The previous study suggested that dominant M1 polarization during DFU could be the leading reason behind impaired wound healing. This study concluded that macrophage M1 polarization predominates in DFU skin tissue. iNOS was increased in HG-induced M1-polarized macrophages; conversely, Arg-1 was decreased. Macrophage pellets after HG stimulation can impair endothelial cell (EC) function by inhibiting cell viability, tube formation and cell migration, indicating M1 macrophage-derived small extracellular vesicles (sEVs) -mediated HUVEC dysfunction. sEVs miR-503 was significantly upregulated in response to HG stimulation, but inhibition of miR-503 in HG-stimulated macrophages attenuated M1 macrophage-induced HUVEC dysfunction. ACO1 interacted with miR-503 and mediated the miR-503 package into sEVs. Under HG stimulation, sEVs miR-503 taken in by HUVECs targeted IGF1R in HUVECs and inhibited IGF1R expression. In HUVECs, miR-503 inhibition improved HG-caused HUVEC dysfunction, whereas IGF1R knockdown aggravated HUVEC dysfunction; IGF1R knockdown partially attenuated miR-503 inhibition effects on HUVECs. In the skin wound model in control or STZ-induced diabetic mice, miR-503-inhibited sEVs improved, whereas IGF1R knockdown further hindered wound healing. Therefore, it can be inferred from the results that the M1 macrophage-derived sEVs miR-503 targets IGF1R in HUVECs, inhibits IGF1R expression, leads to HUVEC dysfunction, and impedes wound healing in diabetic patients, while packaging miR-503 as an M1 macrophage-derived sEVs may be mediated by ACO1.

Mesenchymal Stem Cell Derived Exosomes Therapy in Diabetic Wound Repair

Nowadays, refractory diabetic wounds cause a worldwide medical burden. Mesenchymal stem cells derived exosomes (MSC-Exos) show promise as a solid alternative to existing therapeutics in the latest researches, since MSC-Exos share similar biologic activity but less immunogenicity when compared with MSCs. To facilitate further understanding and application, it is essential to summarize the current progress and limitations of MSC-Exos in the treatment of diabetic wounds. In this review, we introduce the effects of different MSC-Exos on diabetic wounds according to their origins and contents and discuss the specific experimental conditions, target wound cells/pathways, and specific mechanisms. In addition, this paper focuses on the combination of MSC-Exos and biomaterials, which improves the efficacy and utilization of MSC-Exos therapy. Together, exosome therapy has high clinical value and application prospects, both in its role and in combination with biomaterials, while novel drugs or molecules loaded into exosomes as carriers targeting wound cells will be development trends.

Regulation of NcRNA-protein binding in diabetic foot

Non-coding RNA (ncRNA) is a special type of RNA transcript that makes up more than 90 % of the human genome. Although ncRNA typically does not encode proteins, it indirectly controls a wide range of biological processes, including cellular metabolism, development, proliferation, transcription, and post-transcriptional modification. NcRNAs include small interfering RNA (siRNA), PIWI-interacting RNA (piRNA), tRNA-derived small RNA (tsRNA), etc. The most researched of these are miRNA, lncRNA, and circRNA, which are crucial regulators in the onset of diabetes and the development of associated consequences. The ncRNAs indicated above are linked to numerous diabetes problems by binding proteins, including diabetic foot (DF), diabetic nephropathy, diabetic cardiomyopathy, and diabetic peripheral neuropathy. According to recent studies, Mir-146a can control the AKAP12 axis to promote the proliferation and migration of diabetic foot ulcer (DFU) cells, while lncRNA GAS5 can activate HIF1A/VEGF pathway by binding to TAF15 to promote DFU wound healing. However, there are still many unanswered questions about the mechanism of action of ncRNAs. In this study, we explored the mechanism and new progress of ncRNA-protein binding in DF, which can provide help and guidance for the application of ncRNA in the early diagnosis and potential targeted intervention of DFU.

Circulating microRNA as Biomarkers for Gestational Diabetes Mellitus-A Systematic Review and Meta-Analysis

Gestational diabetes mellitus (GDM) is a severe pregnancy complication for both the woman and the child. Women who suffer from GDM have a greater risk of developing Type 2 diabetes mellitus (T2DM) later in life. Identification of any potential biomarkers for the early prediction of gestational diabetes can help prevent the disease in women with a high risk. Studies show microRNA (miRNA) as a potential biomarker for the early discovery of GDM, but there is a lack of clarity as to which miRNAs are consistently altered in GDM. This study aimed to perform a systematic review and meta-analysis to investigate miRNAs associated with GDM by comparing GDM cases with normoglycemic controls. The systematic review was performed according to PRISMA guidelines with searches in PubMed, Web of Science, and ScienceDirect. The primary search resulted in a total of 849 articles, which were screened according to the prior established inclusion and exclusion criteria. Following the screening of articles, the review was based on the inclusion of 35 full-text articles, which were evaluated for risk of bias and estimates of quality, after which data were extracted and relative values for miRNAs were calculated. A meta-analysis was performed for the miRNA species investigated in three or more studies: MiR-29a, miR-330, miR-134, miR-132, miR-16, miR-223, miR-155, miR-122, miR-17, miR-103, miR-125, miR-210, and miR-222. While some miRNAs showed considerable between-study variability, miR-29a, miR-330, miR-134, miR-16, miR-223, and miR-17 showed significant overall upregulation in GDM, while circulating levels of miR-132 and miR-155 were decreased among GDM patients, suggesting further studies of these as biomarkers for early GDM discovery.

Wounds under diabetic milieu: The role of immune cellar components and signaling pathways

A major challenge in the field of diabetic wound healing is to confirm the body's intrinsic mechanism that could sense the immune system damage promptly and protect the wound from non-healing. Accumulating literature indicates that macrophage, a contributor to prolonged inflammation occurring at the wound site, might play such a role in hindering wound healing. Likewise, other immune cell dysfunctions, such as persistent neutrophils and T cell infection, may also lead to persistent oxidative stress and inflammatory reaction during diabetic wound healing. In this article, we discuss recent advances in the immune cellular components in wounds under the diabetic milieu, and the role of key signaling mechanisms that compromise the function of immune cells leading to persistent wound non-healing.

Non-coding RNAs: Role in diabetic foot and wound healing

Diabetic foot ulcer (DFU) and poor wound healing are chronic complications in patients with diabetes. The increasing incidence of DFU has resulted in huge pressure worldwide. Diagnosing and treating this condition are therefore of great importance to control morbidity and improve prognosis. Finding new markers with potential diagnostic and therapeutic utility in DFU has gathered increasing interest. Wound healing is a process divided into three stages: Inflammation, proliferation, and regeneration. Non-coding RNAs (ncRNAs), which are small protected molecules transcribed from the genome without protein translation function, have emerged as important regulators of diabetes complications. The deregulation of ncRNAs may be linked to accelerated DFU development and delayed wound healing. Moreover, ncRNAs can be used for therapeutic purposes in diabetic wound healing. Herein, we summarize the role of microRNAs, long ncRNAs, and circular RNAs in diverse stages of DFU wound healing and their potential use as novel therapeutic targets.

New Horizons of Macrophage Immunomodulation in the Healing of Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) are one of the most costly and troublesome complications of diabetes mellitus. The wound chronicity of DFUs remains the main challenge in the current and future treatment of this condition. Persistent inflammation results in chronic wounds characterized by dysregulation of immune cells, such as M1 macrophages, and impairs the polarization of M2 macrophages and the subsequent healing process of DFUs. The interactive regulation of M1 and M2 macrophages during DFU healing is critical and seems manageable. This review details how cytokines and signalling pathways are co-ordinately regulated to control the functions of M1 and M2 macrophages in normal wound repair. DFUs are defective in the M1-to-M2 transition, which halts the whole wound-healing machinery. Many pre-clinical and clinical innovative approaches, including the application of topical insulin, CCL chemokines, micro RNAs, stem cells, stem-cell-derived exosomes, skin substitutes, antioxidants, and the most recent Phase III-approved ON101 topical cream, have been shown to modulate the activity of M1 and M2 macrophages in DFUs. ON101, the newest clinically approved product in this setting, is designed specifically to down-regulate M1 macrophages and further modulate the wound microenvironment to favour M2 emergence and expansion. Finally, the recent evolution of macrophage modulation therapies and techniques will improve the effectiveness of the treatment of diverse DFUs.

Landscape of the epigenetic regulation in wound healing

Wound healing after skin injury is a dynamic and highly coordinated process involving a well-orchestrated series of phases, including hemostasis, inflammation, proliferation, and tissue remodeling. Epigenetic regulation refers to genome-wide molecular events, including DNA methylation, histone modification, and non-coding RNA regulation, represented by microRNA (miRNA), long noncoding RNA (lncRNA), and circular RNA (circRNA). Epigenetic regulation is pervasively occurred in the genome and emerges as a new role in gene expression at the post-transcriptional level. Currently, it is well-recognized that epigenetic factors are determinants in regulating gene expression patterns, and may provide evolutionary mechanisms that influence the wound microenvironments and the entire healing course. Therefore, this review aims to comprehensively summarize the emerging roles and mechanisms of epigenetic remodeling in wound healing. Moreover, we also pose the challenges and future perspectives related to epigenetic modifications in wound healing, which would bring novel insights to accelerated wound healing.

Severe iatrogenic hypoglycaemia modulates the fibroblast growth factor protein response

INTRODUCTION

There is evidence that fibroblast growth factor (FGF) levels may be implicated in hypoglycaemia, with FGF19 being a potential contributor to insulin-independent pathways driving postprandial hypoglycaemia following bariatric surgery and basic FGF (FGF2) being elevated following mild hypoglycaemia occurring after the glucose tolerance test. However, their response following severe iatrogenic hypoglycaemia is unknown and therefore this pilot exploratory study was undertaken.

METHODS

A case-control study of aged-matched type 2 diabetes (T2D; n = 23) and control (n = 23) subjects who underwent a hyperinsulinaemic clamp, initially to euglycaemia in T2D (5 mmol/L; 90 mg/dl), and then to hypoglycaemia (<2 mmol/L; <36 mg/dl) with subsequent follow-up time course to 24 h. FGF and FGF receptor proteins were determined by Slow Off-rate Modified Aptamer (SOMA)-scan plasma protein measurement.

RESULTS

At baseline, FGF12 (p = .006) was higher and FGF20 (p = .004) was lower in T2D versus controls. At hypoglycaemia, FGF7 was lower in T2D. Post-hypoglycaemic levels of FGF18, FGF19, FGF20 and FGF23 were lower while FGF12 and FGF16 were higher in T2D versus control at different time points. No differences between T2D and controls were seen for FGF1, FGF2, FGF4, FGF6, FGF8, FGF9, FGF10, FGF21 or any of the FGF receptors. At 24 h post-hypoglycaemia, FGF20 (p = .01) differed between controls and T2D, while the levels for the other proteins measured returned to baseline. None of the FGF proteins altered from baseline to euglycaemia when clamped in T2D subjects. FGF23 negatively correlated with fasting blood glucose, but no FGFs correlated with body mass index in T2D.

CONCLUSION

Severe transient hypoglycaemia modulated FGF7, 16, 19, 20 and 23 (known to be associated with diabetes), together with FGF18 and 12, not previously reported to be associated with diabetes but that may be important in the pathophysiology of hypoglycaemia; FGF20 remained low at 24 h. Taken together, these data suggest that recurrent hypoglycaemia may contribute to the development of complications through changes in FGF proteins.

Efficacy of a Self-managed Cooling Intervention for Pain and Physical Activity in Individuals With Recently Healed Chronic Venous Leg and Diabetic Foot Ulcers: A Randomized Controlled Trial

PURPOSE

This aim of this study was to evaluate the clinical efficacy of a self-managed cooling intervention in individuals with recently healed venous leg ulcers (VLUs) and diabetic foot ulcers (DFUs) on pain reduction and physical activity improvement.

DESIGN

A 6-month longitudinal randomized controlled trial.

SUBJECTS AND SETTING

The sample comprised 140 individuals with previously healed VLU and DFU who received care in 3 outpatient wound centers in the Southeastern region of the United States. Participants were randomized to the MUSTCOOL or a placebo cooling patch intervention.

METHODS

The cooling and placebo interventions comprised cooling or cotton-filled patch application to recently healed skin for 30 minutes, 3 times weekly plus standard of care including compression and leg elevation (participants with VLU) or therapeutic footwear and hygiene (participants with DFU) over a 6-month period. Pain severity and intensity were measured with the Brief Pain Inventory and physical activity with the International Physical Activity Questionnaire, which assessed metabolic equivalent of tasks (METs) in minutes per week. Minutes in walking time per week were assessed with an accelerometer. Data were descriptively analyzed for difference changes in scores from baseline to 6 months post-intervention.

RESULTS

Data were analyzed for 81 participants randomized to cooling and placebo groups (VLUs, n = 26/29) and DFU (n = 12/16). Slight reductions in VLU pain severity (-0.5, -0.2) and interference (-0.4, -0.5) and minimal reductions in DFU pain severity (0, -0.1) and interference (0.4/0.1) were achieved. However, pain scores were low to moderate at baseline (mean 4, 0-10 with 10 worst pain possible) in both groups. For physical activity, the MET values showed low physical activity in both groups at baseline with slight improvements noted in VLU cooling and placebo groups (73/799) and DFU (1921/225), respectively. Walking time for the VLU groups improved by 1420/2523 minutes; the DFU groups improved 135/157 minutes, respectively. Findings for outcomes were not statistically significant within or between groups.

CONCLUSIONS

Application of the cooling pack compared to placebo was minimally efficacious in reducing posthealing pain and improving function in this posthealed ulcer population. However for pain, scores were initially low; thus outcomes on pain, while lower, were marginal.

TRIAL REGISTRATION

The study was prospectively registered with ClinicalTrials.gov on December 10, 2015 (Identifier: NCT02626156), https://clinicaltrials.gov/ct2/show/NCT02626156 .

Long Noncoding RNA CASC2 Facilitated Wound Healing through miRNA-155/HIF-1α in Diabetic Foot Ulcers

Diabetic foot ulcers (DFU) are among the serious complications which are closely linked to diabetes mellitus. However, there is still a lack of accurate and effective standard prevention and treatment programs for DFU. In this manuscript, we have investigated the function of lncRNA cancer susceptibility candidate 2 (CASC2)/miR-155/hypoxia-inducible factor 1-alpha (HIF-1α) in the wound healing of DFU. We have analyzed lncRNA CASC2`s expression in the marginal tissues of ulcers in patients and mice with DFU. Additionally, the interaction relationship and mechanism between lncRNA CASC2, miR-155, and HIF-1α were determined, which proved the effects of lncRNA CASC2/miR-155/HIF-1α on fibroblasts apoptosis, proliferation, and migration. According to our study, the lncRNA CASC2's expression was low in the tissues of ulcers of DFU mice and patients. lncRNA CASC2's overexpression promoted fibroblasts migration, proliferation, and inhibited apoptosis and was beneficial for the healing of wounds, preferably in the DFU mice. In addition, lncRNA CASC2 directly targets miR-155 and HIF-1α functions as miR-155's target gene. Overexpression of miR-155 abrogated the function of lncRNA CASC2. Similarly, HIF-1α's inhibition has reversed the effect of miR-155 downregulation on fibroblasts. In general, overexpression of lncRNA CASC2 facilitated wound healing through miR-155/HIF-1α in DFU.

Dichotomous role of miR193b-3p in diabetic foot ulcers maintains inhibition of healing and suppression of tumor formation

Despite the hyperproliferative environment marked by activation of β-catenin and overexpression of c-myc, the epidermis surrounding chronic diabetic foot ulcers (DFUs) is clinically hypertrophic and nonmigratory yet does not undergo malignant transformation. We identified miR193b-3p as a master regulator that contributes to this unique cellular phenotype. We determined that induction of tumor suppressor miR193b-3p is a unique feature of DFUs that is not found in venous leg ulcers, acute wounds, or cutaneous squamous cell carcinoma (SCC). Genomic analyses of DFUs identified suppression of the miR193b-3p target gene network that orchestrates cell motility. Inhibition of migration and wound closure was further confirmed by overexpression of miR193b-3p in human organotypic and murine in vivo wound models, whereas miR193b-3p knockdown accelerated wound reepithelialization in human ex vivo and diabetic murine wounds in vivo. The dominant negative effect of miR193b-3p on keratinocyte migration was maintained in the presence of promigratory miR31-5p and miR15b-5p, which were also overexpressed in DFUs. miR193b-3p mediated antimigratory activity by disrupting stress fiber formation and by decreasing activity of GTPase RhoA. Conversely, miR193b-3p targets that typically participate in malignant transformation were found to be differentially regulated between DFUs and SCC, including the proto-oncogenes KRAS (Kirsten rat sarcoma viral proto-oncogene) and KIT (KIT proto-oncogene). Although miR193b-3p acts as a tumor suppressor contributing to low tumor incidence in DFUs, it also acts as a master inhibitor of cellular migration and epithelialization in DFUs. Thus, miR193b-3p may represent a target for wound healing induction, cancer therapeutics, and diagnostics.

Mesenchymal Stem Cell-Derived Exosomes Loaded with miR-155 Inhibitor Ameliorate Diabetic Wound Healing

Diabetic wounds are one of the debilitating complications that affect up to 20% of diabetic patients. Despite the advent of extensive therapies, the recovery rate is unsatisfactory, and approximately, 25% of patients undergo amputation, thereby demanding alternative therapeutic strategies. On the basis of the individual therapeutic roles of the miR-155 inhibitor and mesenchymal stem cells (MSC)-derived exosomes, we conjectured that the combination of the miR-155 inhibitor and MSC-derived exosomes would have synergy in diabetic wound healing. Herein, miR-155-inhibitor-loaded MSC-derived exosomes showed synergistic effects in keratinocyte migration, restoration of FGF-7 levels, and anti-inflammatory action, leading to accelerated wound healing mediated by negative regulation of miR-155, using an in vitro co-culture model and in vivo mouse model of the diabetic wound. Furthermore, treatment with miR-155-inhibitor-loaded MSC-derived exosomes led to enhanced collagen deposition, angiogenesis, and re-epithelialization in diabetic wounds. This study revealed the therapeutic potential of miR-155-inhibitor-loaded MSC-derived exosomes in diabetic wound healing and opened the doors for encapsulating miRNAs along with antibiotics within the MSC-derived exosomes toward improved management of chronic, nonhealing diabetic wounds.

Beyond the Code: Noncoding RNAs in Skin Wound Healing

An increasing number of noncoding RNAs (ncRNAs) have been found to regulate gene expression and protein functions, playing important roles in diverse biological processes and diseases. Their crucial functions have been reported in almost every cell type and all stages of skin wound healing. Evidence of their pathogenetic roles in common wound complications, such as chronic nonhealing wounds and excessive scarring, is also accumulating. Given their unique expression and functional properties, ncRNAs are promising therapeutic and diagnostic entities. In this review, we discuss current knowledge about the functional roles of noncoding elements, such as microRNAs, long ncRNAs, and circular RNAs, in skin wound healing, focusing on in vivo evidence from studies of human wound samples and animal wound models. Finally, we provide a perspective on the outlook of ncRNA-based therapeutics in wound care.

Increased Expression of miR-155 in Peripheral Blood and Wound Margin Tissue of Type 2 Diabetes Mellitus Patients Associated with Diabetic Foot Ulcer

PURPOSE

To investigate the correlations of miR-155 expression in the peripheral blood and wound margin tissue of patients with diabetic foot ulcer (DFU) and explore the clinical value of miR-155 as a potential biomarker for the diagnosis and treatment outcomes of DFU.

METHODS

Sixty newly diagnosed T2DM patients without DFU (T2DM group), 112 T2DM patients with DFU (DFU group), and 60 healthy controls (NC group) were included. MiR-155 levels in the peripheral blood and wound margin tissue were determined by quantitative real-time PCR, while clinical features and risk factors of DFU were explored. Multiple stepwise logistic regression analysis was used to determine whether miR-155 expression was an independent risk factor for DFU. The diagnostic effectiveness of miR-155 level on DFU was evaluated using ROC curve analysis.

RESULTS

A significant decrease in the expression level of miR-155 was observed in T2DM group compared with NC group (P < 0.05), while a markedly increased miR-155 expression level was noted in DFU group compared with T2DM group (P < 0.01). Moreover, there was a negative correlation between the expression levels of miR-155 with healing rate of DFU. Kaplan-Meier survival curve analysis showed that the cumulative rate of unhealed DFU in miR-155 high expression group is higher than that in miR-155 low expression group, both in peripheral blood and wound margin tissue (log rank, P = 0.004, P < 0.001, respectively). The multivariate logistic regression analysis confirmed that a high expression of miR-155 was an independent risk factor for DFU. The ROC curve analysis indicated that the AUC of miR-155 for the diagnosis of DFU was 0.794, with the optimum sensitivity being 96.82% and the optimum specificity of 95.93%.

CONCLUSION

The increased expression of miR-155 in peripheral blood of T2DM patients is closely related to the occurrence of DFU. MiR-155 is a potentially valuable biomarker for diagnosis and prognosis of DFU.

Dietary supplementation with sulforaphane ameliorates skin aging through activation of the Keap1-Nrf2 pathway

Visible impairments in skin appearance, as well as a subtle decline in its functionality at the molecular level, are hallmarks of skin aging. Activation of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-pathway, which is important in controlling inflammation and oxidative stress that occur during aging, can be triggered by sulforaphane (SFN), an isothiocyanate found in plants from the Brassicaceae family. This study aimed to assess the effects of SFN intake on age-related skin alterations. Male C57BL6 young (2 months) and old (21 months) mice were treated for 3 months with SFN diet (442.5 mg per kg) or control diet. The antioxidant capacities of the skin were increased in old SFN-treated animals as measured by mRNA levels of Nrf2 (P<.001) and its target genes NQO1 (P<.001) and HO1 (P<.01). Protein expression for Nrf2 was also increased in old SFN fed animals (P<.01), but not the protein expression of NQO1 or HO1. Additionally, ROS and MMP9 protein levels were significantly decreased (P<.05) in old SFN fed animals. Histopathological analysis confirmed that there was no difference in epidermal thickness in old, when compared to young, SFN treated animals, while the dermal layer thickness was lower in old vs. young, treated animals (P<.05). Moreover, collagen deposition was improved with SFN treatment in young (P<.05) and structurally significantly improved in the old mice (P<.001). SFN dietary supplementation therefore ameliorates skin aging through activation of the Nrf2-pathway.

Differential regulation of miR-21-5p delays wound healing of melanocyte-deprived vitiligo skin by modulating the expression of tumor-suppressors PDCD4 and Maspin

The loss of melanocytes in vitiligo is associated with architectural, transcriptional, and cellular perturbations of keratinocytes and manifests as a reduced proliferation potential in vitro and delayed re-epithelialization in vivo. To understand the molecular mechanisms underlying this delay, microRNA (miRNA) profiling was performed on split skin biopsies collected on Day 1 (basal level) and Day 14 (wound re-epithelialization) from nonlesional (NL) and lesional (L) skin of five subjects with stable nonsegmental vitiligo and 129 miRNAs were found to be differentially regulated between the NL and L healed epidermis. miR-21-5p, expressed at comparable levels on NL and L Day 1 samples, demonstrated significant upregulation during re-epithelialization. However, the extent of its upregulation was relatively lower in L (10 times compared to Day 1) as compared to NL skin (17 times compared to Day 1). The overexpression of miR-21 in keratinocytes led to a significant increase in the expression of proliferation markers (Ki67 and MCM6 messenger RNA, Ki67 positivity), along with an increase in keratinocyte migration. Using a small interfering RNA mediated knockdown approach, we further demonstrated that miR-21-5p mediates its effects by suppressing the expression of programmed cell death 4 (PDCD4) and mammary serine protease inhibitor (Maspin), both tumor-suppressor genes. Investigation of clinical samples corroborated the lower miR-21 levels and a higher expression of PDCD4 and Maspin in L Day 14 compared to the NL Day 14 epidermis. In conclusion, this study revealed that a relatively lower upregulation of miR-21-5p in L skin leads to significantly higher levels of PDCD4 and Maspin, delaying wound re-epithelialization by reducing the proliferation and migration of keratinocytes.

Adipose-related microRNAs as modulators of the cardiovascular system: the role of epicardial adipose tissue

Adipose tissue expansion and subsequent metabolic dysfunction has been considered one of the major risk factors for development of cardiometabolic disease. Epicardial adipose tissue (EAT) in particular is a unique subtype of visceral adipose tissue located on the surface of the heart, around the coronary arteries. Due to its proximity, EAT can modulate the local metabolic and immune function of cardiomyocytes and coronary arteries. Several microRNAs have been described as key players in both cardiac and vascular function that when dysregulated will contribute to dysfunction. Here we review the influence of obesity in the crosstalk between specific adipose tissue types, in particular the EAT-secreted microRNAs, as key modulators of cardiac disease progression, not only as early biomarkers but also as therapeutic targets for cardiometabolic disease.

Limited Treatment Options for Diabetic Wounds: Barriers to Clinical Translation Despite Therapeutic Success in Murine Models

Significance: Millions of people worldwide suffer from diabetes mellitus and its complications, including chronic diabetic wounds. To date, there are few widely successful clinical therapies specific to diabetic wounds beyond general wound care, despite the vast number of scientific discoveries in the pathogenesis of defective healing in diabetes. Recent Advances: In recent years, murine animal models of diabetes have enabled the investigation of many possible therapeutics for diabetic wound care. These include specific cell types, growth factors, cytokines, peptides, small molecules, plant extracts, microRNAs, extracellular vesicles, novel wound dressings, mechanical interventions, bioengineered materials, and more. Critical Issues: Despite many research discoveries, few have been translated from their success in murine models to clinical use in humans. This massive gap between bench discovery and bedside application begs the simple and critical question: what is still missing? The complexity and multiplicity of the diabetic wound makes it an immensely challenging therapeutic target, and this lopsided progress highlights the need for new methods to overcome the bench-to-bedside barrier. How can laboratory discoveries in animal models be effectively translated to novel clinical therapies for human patients? Future Directions: As research continues to decipher deficient healing in diabetes, new approaches and considerations are required to ensure that these discoveries can become translational, clinically usable therapies. Clinical progress requires the development of new, more accurate models of the human disease state, multifaceted investigations that address multiple critical components in wound repair, and more innovative research strategies that harness both the existing knowledge and the potential of new advances across disciplines.

Epigenetic regulation of cellular functions in wound healing

Stringent spatiotemporal regulation of the wound healing process involving multiple cell types is associated with epigenetic mechanisms of gene regulation, such as DNA methylation, histone modification and chromatin remodelling, as well as non-coding RNAs. Here, we discuss the epigenetic changes that occur during wound healing and the rapidly expanding understanding of how these mechanisms affect healing resolution in both acute and chronic wound milieu. We provide a focussed overview of current research into epigenetic regulators that contribute to wound healing by specific cell type. We highlight the role of epigenetic regulators in the molecular pathophysiology of chronic wound conditions. The understanding of how epigenetic regulators can affect cellular functions during normal and impaired wound healing could lead to novel therapeutic approaches, and we outline questions that can provide guidance for future research on epigenetic-based interventions to promote healing. Dissecting the dynamic interplay between cellular subtypes involved in wound healing and epigenetic parameters during barrier repair will deepen our understanding of how to improve healing outcomes in patients affected by chronic non-healing wounds.

The progress, prospects, and challenges of the use of non-coding RNA for diabetic wounds

Chronic diabetic wounds affect the quality of life of patients, resulting in significant social and economic burdens on both individuals and the health care system. Although treatment methods for chronic diabetic wounds have been explored, there remains a lack of effective treatment strategies; therefore, alternative strategies must be explored. Recently, the abnormal expression of non-coding RNA in diabetic wounds has received widespread attention since it is an important factor in the development of diabetic wounds. This article reviews the regulatory role of three common non-coding RNAs (microRNA [miRNA], long non-coding RNA [lncRNA], and circular RNA [circRNA]) in diabetic wounds and discusses the diagnosis, treatment potential, and challenges of non-coding RNA in diabetic wounds. This article provides insights into new strategies for diabetic wound diagnosis and treatment at the genetic and molecular levels.

Improved diabetic wound healing by LFcinB is associated with relevant changes in the skin immune response and microbiota

Bovine lactoferricin (LFcinB) has antimicrobial and immunomodulatory properties; however, the effects on diabetic wound healing remain poorly understood. The wound healing potential of LFcinB was investigated with in vitro, ex vivo, and in vivo models. Cell migration and proliferation were tested on keratinocytes and on porcine ears. A type 1 diabetic mouse model was also used to evaluate wound healing kinetics, bacterial diversity patterns, and the effect of LFcinB on oxidative stress, macrophage phenotype, angiogenesis, and collagen deposition. LFcinB increased keratinocyte migration in vitro (p < 0.05) and ex vivo (p < 0.001) and improved wound healing in diabetic mice (p < 0.05), though not in normoglycemic control mice. In diabetic mouse wounds, LFcinB treatment led to the eradication of Bacillus pumilus, a decrease in Staphylococcus aureus, and an increase in the Staphylococcus xylosus prevalence. LFcinB increased angiogenesis in diabetic mice (p < 0.01), but this was decreased in control mice (p < 0.05). LFcinB improved collagen deposition in both diabetic and control mice (p < 0.05). Both oxidative stress and the M1-to-M2 macrophage ratios were decreased in LFcinB-treated wounds of diabetic animals (p < 0.001 and p < 0.05, respectively) compared with saline, suggesting a downregulation of inflammation in diabetic wounds. In conclusion, LFcinB treatment demonstrated noticeable positive effects on diabetic wound healing.

Development of a novel RNAi therapy: Engineered miR-31 exosomes promoted the healing of diabetic wounds

RATIONALE

Chronic wounds associated with diabetes exact a heavy burden on individuals and society and do not have a specific treatment. Exosome therapy is an extension of stem cell therapy, and RNA interference (RNAi)-based therapy is a type of advanced precision therapy. Based on the discovery of chronic wound-related genes in diabetes, we combined exosome therapy and RNAi therapy through an engineering approach for the treatment of diabetic chronic wounds.

METHODS

We combined exosome therapy and RNAi therapy to establish a precision therapy for diabetes-associated wounds via an engineered exosome approach.

RESULTS

First, chronic diabetic wounds express low levels of miR-31-5p compared with nondiabetic wounds, and an miR-31-5p mimic was shown to be effective in promoting the proliferation and migration of three wound-related cell types in vitro. Second, bioinformatics analysis, luciferase reporter assays and western blotting suggested that miR-31-5p promoted angiogenesis, fibrogenesis and reepithelization by inhibiting factor-inhibiting HIF-1 (HIF1AN, also named FIH) and epithelial membrane protein-1 (EMP-1). Third, engineered miR-31 exosomes were generated as a miR-31-5p RNAi therapeutic agent. In vivo, the engineered miR-31 exosomes promoted diabetic wound healing by enhancing angiogenesis, fibrogenesis and reepithelization.

CONCLUSION

Engineered miR-31 exosomes are an ideal disease pathophysiology-initiated RNAi therapeutic agent for diabetic wounds.

Metformin regulates inflammation and fibrosis in diabetic kidney disease through TNC/TLR4/NF-κB/miR-155-5p inflammatory loop

BACKGROUND

Type 2 diabetes mellitus (T2DM) is significantly increasing worldwide, and the incidence of its complications is also on the rise. One of the main complications of T2DM is diabetic kidney disease (DKD). The glomerular filtration rate (GFR) and urinary albumin creatinine ratio (UACR) increase in the early stage. As the disease progresses, UACR continue to rise and GFR begins to decline until end-stage renal disease appears. At the same time, DKD will also increase the incidence and mortality of cardiovascular and cerebrovascular diseases. At present, the pathogenesis of DKD is not very clear. Therefore, exploration of the pathogenesis of DKD to find a treatment approach, so as to delay the development of DKD, is essential to improve the prognosis of DKD.

AIM

To detect the expression of tenascin-C (TNC) in the serum of T2DM patients, observe the content of TNC in the glomerulus of DKD rats, and detect the expression of TNC on inflammatory and fibrotic factors in rat mesangial cells (RMCs) cultured under high glucose condition, in order to explore the specific molecular mechanism of TNC in DKD and bring a new direction for the treatment of DKD.

METHODS

The expression level of TNC in the serum of diabetic patients was detected by enzyme-linked immunosorbent assay (ELISA), the protein expression level of TNC in the glomerular area of DKD rats was detected by immunohistochemistry, and the expression level of TNC in the rat serum was detected by ELISA. Rat glomerular mesangial cells were cultured. Following high glucose stimulation, the expression levels of related proteins and mRNA were detected by Western blot and polymerase chain reaction, respectively.

RESULTS

ELISA results revealed an increase in the serum TNC level in patients with T2DM. Increasing UACR and hypertension significantly increased the expression of TNC (P < 0.05). TNC expression was positively correlated with glycosylated haemoglobin (HbA1c) level, body mass index, systolic blood pressure, and UACR (P < 0.05). Immunohistochemical staining showed that TNC expression in the glomeruli of rats with streptozotocin-induced diabetes was significantly increased compared with normal controls (P < 0.05). Compared with normal rats, serum level of TNC in diabetic rats was significantly increased (P < 0.05), which was positively correlated with urea nitrogen and urinary creatinine (P < 0.05). The levels of TNC, Toll-like receptor-4 (TLR4), phosphorylated nuclear factor-κB p65 protein (Ser536) (p-NF-κB p65), and miR-155-5p were increased in RMCs treated with high glucose (P < 0.05). The level of TNC protein peaked 24 h after high glucose stimulation (P < 0.05). After TNC knockdown, the levels of TLR4, p-NF-κB p65, miR-155-5p, connective tissue growth factor (CTGF), and fibronectin (FN) were decreased, revealing that TNC regulated miR-155-5p expression through the TLR4/NF-κB p65 pathway, thereby regulating inflammation (NF-κB p65) and fibrosis (CTGF and FN) in individuals with DKD. In addition, metformin treatment may relive the processes of inflammation and fibrosis in individuals with DKD by reducing the levels of the TNC, p-NF-κB p65, CTGF, and FN proteins.

CONCLUSION

TNC can promote the occurrence and development of DKD. Interfering with the TNC/TLR4/NF-κB p65/miR-155-5p pathway may become a new target for DKD treatment.

Stromal cell-derived factor loaded co-electrospun hydrophilic/hydrophobic bicomponent membranes for wound protection and healing

Chronic wounds are one of the key concerns for people with diabetes, frequently leading to infections and non-healing ulcers, and finally resulting in the amputation of limbs/organs. Stromal cell-derived factor 1 (SDF1) is a major chemokine that plays a significant role in tissue repair, vascularization, and wound healing. However, the long-term sustained delivery of SDF1 in a chronic wound environment is a great challenge. In order to facilitate the sustained release of SDF1 in diabetic wounds, it could be incorporated into wound-healing patches. Herein, we report the fabrication of a hydrophilic/hydrophobic bicomponent fiber-based membrane, where SDF1 was encapsulated inside hydrophilic fibers, and its applicability in wound healing. A co-electrospinning technique was employed for the fabrication of polymeric membranes where PVA and PCL form the hydrophilic and hydrophobic components, respectively. Morphological analysis of the developed membranes was conducted via scanning electron microscopy (SEM). The mechanical strength of the membranes was investigated via uniaxial tensile testing. The water uptake capacity of the membranes was also determined to understand the hydrophilicity and exudate uptake capacity of the membranes. To understand the proliferation, viability, and migration of skin-specific cells in the presence of SDF1-loaded membranes, in vitro cell culture experiments were carried out using fibroblasts, keratinocytes, and endothelial cells. The results showed the excellent porous morphology of the developed membranes with distinguishable differences in fiber diameters for the PVA and PCL fibers. The developed membranes possessed enough mechanical strength for use as wound-healing membranes. The co-electrospun membranes showed good exudate uptake capacity. The controlled and extended delivery of SDF1 from the developed membranes was observed over a prolonged period. The SDF1-loaded membranes showed enhanced cell proliferation, cell viability, and cell migration. These biocompatible and biodegradable SDF1-loaded bicomponent membranes with excellent exudate uptake capacity, and cell proliferation and cell migration properties can be exploited as a novel wound-dressing membrane aimed at chronic diabetic wounds.

miR-155 Contributes to Normal Keratinocyte Differentiation and Is Upregulated in the Epidermis of Psoriatic Skin Lesions

The role of microRNAs (miRNAs) during keratinocyte (KC) differentiation and in skin diseases with epidermal phenotypes has attracted strong interest over the past few years. However, combined mRNA and miRNA expression analyses to elucidate the intricate mRNA–miRNA networks of KCs at different stages of differentiation have not been performed yet. In the present study, we investigated the dynamics of miRNA and mRNA expression during KC differentiation in vitro and in normal and psoriatic epidermis. While we identified comparable numbers of up- and downregulated mRNAs (49% and 51%, respectively), miRNAs were predominantly upregulated (76% vs 24%) during KC differentiation. Further bioinformatics analyses suggested an important inhibitory role for miR-155 in KC differentiation, as it was repressed during KC differentiation in normal skin but strongly upregulated in the epidermis of psoriatic skin lesions. Mimicking the inflammatory milieu of psoriatic skin in vitro, we could show that the pro-inflammatory cytokines IL17, IL1β and INFγ synergistically upregulated miR-155 expression in KCs. Forced over-expression of miR-155 in human in vitro skin models specifically reduced the expression of loricrin (LOR) in KCs, indicating that miR-155 interferes with the establishment of a normal epidermal barrier. Together, our data indicate that downregulation of miR-155 during KC differentiation is a crucial step for epidermal barrier formation. Furthermore, its strong upregulation in psoriatic lesions suggests a contributing role of miR-155 in the altered keratinocyte differentiation observed in psoriasis. Therefore, miR-155 represents as a potential target for treating psoriatic skin lesions.

Mechanistic Actions of microRNAs in Diabetic Wound Healing

Wound healing is a complex biological process that is impaired under diabetes conditions. Chronic non-healing wounds in diabetes are some of the most expensive healthcare expenditures worldwide. Early diagnosis and efficacious treatment strategies are needed. microRNAs (miRNAs), a class of 18–25 nucleotide long RNAs, are important regulatory molecules involved in gene expression regulation and in the repression of translation, controlling protein expression in health and disease. Recently, miRNAs have emerged as critical players in impaired wound healing and could be targets for potential therapies for non-healing wounds. Here, we review and discuss the mechanistic background of miRNA actions in chronic wounds that can shed the light on their utilization as specific wound healing biomarkers.

Lack of lymphocytes impairs macrophage polarization and angiogenesis in diabetic wound healing

AIMS

This study aimed to investigate the effect of lymphocytes in wound healing and the underlying mechanisms, in diabetic and non-diabetic mice, using Balb/c recombination activating gene (Rag)-2 and interleukin 2 receptor gamma (IL-2Rγ) double knockout (KO) (RAG2^-/- IL-2Rγ^-/-) mice.

MAIN METHODS

Wound healing in vivo was performed in control and STZ-induced diabetic mice, in both KO and WT mice. Inflammation and ROS production were evaluated by immunofluorescence microscopy analysis, antioxidant enzymes and angiogenesis were evaluated by quantitative PCR and immunofluorescence microscopy analysis, and wound closure kinetics evolution was evaluated by measurement of acetate tracing of the wound area.

KEY FINDINGS

Wound closure was significantly delayed in KO mice, where the M1/M2 macrophage ratio and basal ROS levels were significantly increased, while antioxidant defenses and angiogenesis were significantly decreased. Moreover, the expected increase in matrix metallopeptidase (MMP)-9 protein levels in diabetic conditions was not observed in KO mice, suggesting that the mechanisms leading to the increase in MMP-9 observed in diabetic wounds may in part be lymphocyte-dependent.

SIGNIFICANCE

Our results indicate that lack of lymphocytes compromises wound healing independent of diabetes. The lack of these cells, even in non-diabetic mice, mimics the phenotype observed in wounds under diabetic conditions. Moreover, the combination of diabetes and the lack of lymphocytes, further impair the wound healing conditions, indicating that when the innate regulatory function is lost in these KO mice, excessive M1 polarization, poor angiogenesis and impaired wound healing are worsen.

Exosomes derived from mmu_circ_0000250-modified adipose-derived mesenchymal stem cells promote wound healing in diabetic mice by inducing miR-128-3p/SIRT1-mediated autophagy

More and more evidence advises that circular RNAs (circRNAs) function critically in regulating different disease microenvironments. Our previous study found that autotransplantation of adipose-derived mesenchymal stem cells (ADSCs) promotes diabetes wound healing. Exosomes derived in ADSCs play an important regulatory role. This study aimed to characterize if mmu_circ_0000250 played a role in ADSC-exosome-mediated full-thickness skin wound repair in diabetic rats. Endothelial progenitor cells (EPCs) were selected to study the therapeutic mechanism of exosomes in high-glucose (HG)-induced cell damage and dysfunction. Analysis and luciferase reporter assay were utilized to explore the interaction among mmu_circ_0000250, miRNA (miR)-128-3p, and sirtuin (SIRT)1. The diabetic rats were used to confirm the therapeutic effect of mmu_circ_0000250 against exosome-mediated wound healing. Exosomes containing a high concentration of mmu_circ_0000250 had a greater therapeutic effect on restoration of the function of EPCs by promotion autophagy activation under HG conditions. Expression of mmu_circ_0000250 promoted SIRT1 expression by miR-128-3p adsorption, which was confirmed via luciferase reporter assay and bioinformatics analysis. In vivo, exosomes containing a high concentration of mmu_circ_0000250 had a more therapeutic effect on wound healing when compared with wild-type exosomes from ADSCs. Immunohistochemistry and immunofluorescence detection showed that mmu_circ_0000250 increased angiopoiesis with exosome treatment in wound skin and suppressed apoptosis by autophagy activation. In conclusion, we verified that mmu_circ_0000250 enhanced the therapeutic effect of ADSC-exosomes to promote wound healing in diabetes by absorption of miR-128-3p and upregulation of SIRT1. Therefore, these findings advocate targeting the mmu_circ_0000250/miR-128-3p/SIRT1 axis as a candidate therapeutic option for diabetic ulcers.

Neonatal Injury Increases Gut Permeability by Epigenetically Suppressing E-Cadherin in Adulthood

Altered intestinal epithelial integrity is an important susceptibility trait in inflammatory bowel disease (IBD), and early life stressors are reported to contribute to this disease susceptibility in adulthood. To identify disease mechanisms associated with early-life trauma that exacerbate IBD in adulthood, we used a "double-hit" neonatal inflammation (NI) and adult inflammation (AI) model that exhibits more severe mucosal injury in the colon later in life. In this study, we explore the underlying mechanisms of this aggravated injury. In rats exposed to both NI and AI, we found sustained increases in colonic permeability accompanied by significantly attenuated expression of the epithelial junction protein E-cadherin. Quantitative RT-PCR revealed a decreased Cdh1 (gene of E-cadherin) mRNA expression in NI + AI rats compared with NI or AI rats. Next, we performed microRNA microarrays to identify potential regulators of E-cadherin in NI + AI rats. We confirmed the overexpression of miR-155, a predicted regulator of E-cadherin, and selected it for further analysis based on reported significance in human IBD. Using ingenuity pathway analysis software, the targets and related canonical pathway of miR-155 were analyzed. Mechanistic studies identified histone hyperacetylation at the Mir155 promoter in NI + AI rats, concomitant with elevated RNA polymerase II binding. In vitro, E-cadherin knockdown markedly increased epithelial cell permeability, as did overexpression of miR-155 mimics, which significantly suppressed E-cadherin protein. In vivo, NI + AI colonic permeability was significantly reversed with administration of miR-155 inhibitor rectally. Our collective findings indicate that early-life inflammatory stressors trigger a significant and sustained epithelial injury by suppressing E-cadherin through epigenetic mechanisms.

miR-488 mediates negative regulation of the AKT/NF-κB pathway by targeting Rac1 in LPS-induced inflammation

Endometritis is an inflammatory change in the structure of the endometrium due to various causes and is a common cause of infertility. Studies have confirmed that microRNAs (miRNAs) play a key regulatory role in various inflammatory diseases. However, the miRNA-mediated mechanism of endometrial inflammation induced by lipopolysaccharides (LPS) remains unclear. In this study, real-time quantitative polymerase chain reaction, Western blot analysis, immunofluorescence and Rac family small GTPase 1 (Rac1) interference were used to reveal the overexpression of miR-488 in the LPS-induced bovine uterus, and the effect of protein kinase B κ-light chain enhancement of the nuclear factor-activated B cells (AKT/NF-κB) pathway in intimal epithelial cells. The results showed that the expression of inflammatory cytokines such as interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α in the experimental group was significantly lower than that in the control group when miR-488 was overexpressed. Similar results were observed in the expression levels of p-AKT, p-IKK, and p-p65 proteins. In addition, the dual-luciferase reporter system confirmed that miRNA-488 may directly target the 3'-untranslated region of Rac1. In turn, the expression of Rac1 was inhibited. Moreover, the nuclear translocation of NF-κB was inhibited, and meanwhile, the accumulation of reactive oxygen species (ROS) in the cells was reduced. Thus, we provide basic data for the negative regulation of miR-488 in LPS-induced inflammation by inhibiting ROS production and the AKT/NF-kB pathway in intimal epithelial cells.

Pharmacological control of inflammation in wound healing

Wound inflammation is a rapid and highly orchestrated process that significantly impacts the wound healing cascade. Consequent to injury, a series of events set off that include inflammatory, proliferation and maturation phases leading to wound closure and restoration of normal skin integrity. Stimuli causing stress to host immune system or induce inflammatory response include tissue damage and pathogenic microbial infection.Several evidences points towards the positive role of inflammation as it essential to fight against the attack of invading pathogens and to remove dead tissues from the site of injury. Besides its positive role, prolonged inflammation is injurious and may result in deregulated stages of the wound healing which may lead to excessive scarring. Achieving balance in inflammatory cascade is one of the challenging tasks for development of a wound healing drug. This review mainly focuses on the pharmacological control of inflammation by agents which critically balance the inflammatory cascade. However, none of the agent is available in the healthcare market which exclusively plays a role in wound repair. In this review we shall explore different factors or agents affecting inflammation in wound healing. This information might be helpful in designing and development new process, technologies or drugs for better management of wound care. In addition, understanding the effect of inflammation on the outcome of the healing process will serve as a significant milestone in the area of pathological tissue repair.

Downregulation of microRNA-302b-3p relieves oxygen-glucose deprivation/re-oxygenation induced injury in murine hippocampal neurons through up-regulating Nrf2 signaling by targeting fibroblast growth factor 15/19

MicroRNAs have emerged as critical mediators of cerebral ischaemia/reperfusion injury. Recent studies have demonstrated that microRNA-302b-3p (miR-302b-3p) plays an important role in regulating apoptosis and oxidative stress in various cells. However, whether miR-302b-3p is involved in regulating cerebral ischaemia/reperfusion injury-induced neuronal apoptosis and oxidative stress remains unknown. In the present study, we explored the potential function and molecular mechanism of miR-302b-3p in oxygen-glucose deprivation/re-oxygenation (OGD/R)-induced neuronal injury, using an in vitro model of cerebral ischaemia/reperfusion injury. We found that miR-302b-3p expression was up-regulated by OGD/R treatment in neurons. The inhibition of miR-302b-3p improved cell viability, and reduced apoptosis and the production of reactive oxygen species, showing a protective effect against OGD/R-induced injury. Interestingly, miR-302b-3p was shown to target and modulate murine fibroblast growth factor 15 (FGF15). Moreover, our results showed that miR-302b-3p down-regulation contributed to the promotion of nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE)-mediated antioxidant signaling associated with the inactivation of glycogen synthase kinase-3β. However, the knockdown of FGF15 significantly reversed the miR-302b-3p inhibition-mediated protective effect in OGD/R-treated neurons. Overall, these results demonstrated that miR-302b-3p inhibition confers a neuroprotective effect in OGD/R-treated neurons by up-regulating Nrf2/ARE antioxidant signaling via targeting FGF15, providing a novel target for neuroprotection in cerebral ischaemia/reperfusion injury.