MiR-195-5p and miR-205-5p in extracellular vesicles isolated from diabetic foot ulcer wound fluid decrease angiogenesis by inhibiting VEGFA expression

Keratinocyte-derived small extracellular vesicles delay diabetic wound healing by triggering fibroblasts autophagy

Keratinocyte and fibroblast dysfunctions contribute to delayed healing of diabetic wounds. Small extracellular vesicles (sEV) are key mediators of intercellular communication and are involved in the pathogenesis of several diseases. Recent findings suggest that sEV derived from high-glucose-treated keratinocyte (HaCaT-HG-sEV) can transport LINC01435 to inhibit tube formation and migration of HUVECs, thereby delaying wound healing. This study aimed to elucidate sEV-related communication mechanisms between keratinocytes and fibroblasts during diabetic wound healing. HaCaT-HG-sEV treatment and LINC01435 overexpression significantly decreased fibroblast collagen level and migration ability but significantly increased fibroblast autophagy. However, treatment with an autophagy inhibitor suppressed LINC01435 overexpression-induced decrease in collagen levels in fibroblasts. In diabetic mice, HaCaT-HG-sEV treatment decreased collagen levels and increased the expression of the autophagy-related proteins Beclin-1 and LC3 at the wound site, thereby delaying wound healing. Conclusively, LINC01435 in keratinocyte-derived sEV activates fibroblast autophagy and reduces fibroblast collagen synthesis, leading to impaired 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.

Circ-Luc7l Absence Attenuates Diabetic Nephropathy Progression by Reducing Mesangial Cell Excessive Proliferation, Inflammation, and Extracellular Matrix Accumulation via Mediating the miR-205-5p/Tgfbr1 Pathway

Diabetic nephropathy (DN) threatens the survival quality of patients, with complex pathogenesis. Circular RNA (circRNA) dysregulation occurs in DN development. This work aimed to investigate the role of circ-Luc7l in DN cell models and related molecular mechanisms. The expression of circ-Luc7l, microRNA (miR)-205-5p, and transforming growth factor-beta receptor 1 (Tgfbr1) was examined by real-time quantitative PCR (RT-qPCR). Cell viability and proliferation were detected by Cell Counting Kit-8 (CCK-8) assay and EdU assay. The expression of extracellular matrix (ECM)-related markers and Tgrbr1 protein was measured by Western blot. The binding between miR-205-5p and circ-Luc7l or Tgfbr1 was validated by dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay, or RNA pull-down assay. Experimental animal models were established to elucidate the function of circ-Luc7l in vivo. Circ-Luc7l expression was notably enhanced in high glucose (HG)-treated mesangial cells. Knockdown of circ-Luc7l attenuated HG-induced cell proliferation, inflammation, and ECM accumulation in vitro and relieved inflammation and ECM accumulation of kidneys of diabetic mice in vivo. Circ-Luc7l targeted miR-205-5p, and miR-205-5p inhibition rescued the depletion effects of circ-Luc7l knockdown on cell proliferation, inflammation, and ECM accumulation. MiR-205-5p bound to Tgfbr1 whose expression was negatively regulated by circ-Luc7l. Tgfbr1 overexpression also rescued the depletion effects of circ-Luc7l knockdown on cell proliferation, inflammation, and ECM accumulation. In HG conditions, increased circ-Luc7l upregulated Tgfbr1 expression via targeting miR-205-5p to induce DN progression.

Role of Exosomal miR-205-5p Cargo in Angiogenesis and Cell Migration

Exosomes or small extracellular vesicles (sEVs) represent a pivotal component in intercellular communication, carrying a diverse array of biomolecules. Several factors can affect sEVs release dynamics, as occurs in hyperglycemia or inflammation. In fact, sEVs release has been associated with the promotion of physio-pathological processes. Among the sEVs cargo, microRNAs play an essential role in cell-to-cell regulation. More concretely, miR-205-5p is related to angiogenesis and cell proliferation. The aim of this study is to understand the specific role of sEVs containing miR-205-5p under high glucose conditions. ARPE-19 cells were cultured with high glucose (HG) for 5 days. sEVs were isolated and characterized. sEVs from ARPE-19 were used for angiogenesis and cell proliferation. HG increased sEVs release but downregulated miR-205-5p cargo expression compared to the control. sEVs from HG-treated ARPE-19 cells promoted tube formation and migration processes. In contrast, miR-205-5p overexpression (by mimic transfection) decreased angiogenesis and cell migration. Our results demonstrate how ARPE-19 cells respond to HG challenge by increasing sEVs with weak miR-205-5p cargo. The absence of this miRNA in sEVs is enough to promote angiogenesis. In contrast, restoring sEVs-miR-205-5p levels decreased it. These findings open new possibilities in sEVs-based therapies containing miR-205-5p against angiogenesis.

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.

Role of exosome-derived miRNAs in diabetic wound angiogenesis

Chronic wounds with high disability are among the most common and serious complications of diabetes. Angiogenesis dysfunction impair wound healing in patients with diabetes. Compared with traditional therapies that can only provide symptomatic treatment, stem cells-owing to their powerful paracrine properties, can alleviate the pathogenesis of chronic diabetic wounds and even cure them. Exosome-derived microRNAs (miRNAs), important components of stem cell paracrine signaling, have been reported for therapeutic use in various disease models, including diabetic wounds. Exosome-derived miRNAs have been widely reported to be involved in regulating vascular function and have promising applications in the repair and regeneration of skin wounds. Therefore, this article aims to review the current status of the pathophysiology of exosome-derived miRNAs in the diabetes-induced impairment of wound healing, along with current knowledge of the underlying mechanisms, emphasizing the regulatory mechanism of angiogenesis, we hope to document the emerging theoretical basis for improving wound repair by restoring angiogenesis in diabetes.

Novel mediators regulating angiogenesis in diabetic foot ulcer healing

A non-healing diabetic foot ulcer (DFU) is a debilitating clinical problem amounting to socioeconomic and psychosocial burdens. DFUs increase morbidity due to prolonged treatment and mortality in the case of non-treatable ulcers resulting in gangrene and septicemia. The overall amputation rate of the lower extremity with DFU ranges from 3.34% to 42.83%. Wound debridement, antibiotics, applying growth factors, negative pressure wound therapy, hyperbaric oxygen therapy, topical oxygen, and skin grafts are common therapies for DFU. However, recurrence and nonhealing ulcers are still major issues. Chronicity of inflammation, hypoxic environment, poor angiogenesis, and decreased formation of the extracellular matrix (ECM) are common impediments leading to nonhealing patterns of DFUs. Angiogenesis is crucial for wound healing since proper vessel formation facilitates nutrients, oxygen, and immune cells to the ulcer tissue to help in clearing out debris and facilitate healing. However, poor angiogenesis due to decreased expression of angiogenic mediators and matrix formation results in nonhealing and ultimately amputation. Multiple proangiogenic mediators and vascular endothelial growth factor (VEGF) therapy exist to enhance angiogenesis, but the results are not satisfactory. Thus, there is a need to investigate novel pro-angiogenic mediators that can either alone or in combination enhance the angiogenesis and healing of DFUs. In this article, we critically reviewed the existing pro-angiogenic mediators followed by potentially novel factors that might play a regulatory role in promoting angiogenesis and wound healing in DFUs.

miR-205-5p inhibits homocysteine-induced pulmonary microvascular endothelium dysfunction by targeting FOXO1

Homocysteine (Hcy) is a risk factor for multiple chronic diseases, and vascular endothelial cell injury has been regarded as the initiating step for this process. miRNAs are involved in Hcy-induced endothelial dysfunction, while the underlying mechanism and roles of miRNAs in pulmonary endothelial dysfunction induced by homocysteine are unknown. Here, we find that miR-205-5p alleviates pulmonary endothelial dysfunction by targeting FOXO1 in CBS +/‒ mice to protect against Hcy-induced pulmonary endothelial dysfunction. Mechanistically, we show that Hcy can lead to DNA hypermethylation of the miR-205-5p promoter due to the increased binding of DNMT1 to its promoter, which contributes to reduction of miR-205-5p expression. In summary, miR-205-5p promoter hypermethylation causes downregulation of miR-205-5p expression, resulting in a reduction in miR-205-5p binding to FOXO1 during homocysteine-induced pulmonary endothelial dysfunction. Our data indicate that miR-205-5p may be a potential therapeutic target against Hcy-induced pulmonary injury.

In-silico engineering of RNA nanoplatforms to promote the diabetic wound healing

One of the most notable required features of wound healing is the enhancement of angiogenesis, which aids in the acceleration of regeneration. Poor angiogenesis during diabetic wound healing is linked to a shortage of pro-angiogenic or an increase in anti-angiogenic factors. As a result, a potential treatment method is to increase angiogenesis promoters and decrease suppressors. Incorporating microRNAs (miRNAs) and small interfering RNAs (siRNAs), two forms of quite small RNA molecules, is one way to make use of RNA interference. Several different types of antagomirs and siRNAs are now in the works to counteract the negative effects of miRNAs. The purpose of this research is to locate novel antagonists for miRNAs and siRNAs that target multiple genes to promote angiogenesis and wound healing in diabetic ulcers.In this context, we used gene ontology analysis by exploring across several datasets. Following data analysis, it was processed using a systems biology approach. The feasibility of incorporating the proposed siRNAs and miRNA antagomirs into polymeric bioresponsive nanocarriers for wound delivery was further investigated by means of a molecular dynamics (MD) simulation study. Among the three nanocarriers tested (Poly (lactic-co-glycolic acid) (PLGA), Polyethylenimine (PEI), and Chitosan (CTS), MD simulations show that the integration of PLGA/hsa-mir-422a is the most stable (total energy = -1202.62 KJ/mol, Gyration radius = 2.154 nm, and solvent-accessible surface area = 408.416 nm²). With values of -25.437 KJ/mol, 0.047 nm for the Gyration radius, and 204.563 nm² for the SASA, the integration of the second siRNA/ Chitosan took the last place. The results of the systems biology and MD simulations show that the suggested RNA may be delivered through bioresponsive nanocarriers to speed up wound healing by boosting angiogenesis.

MicroRNAs and Gene Regulatory Networks Related to Cleft Lip and Palate

Cleft lip and palate is one of the most common congenital birth defects and has a complex etiology. Either genetic or environmental factors, or both, are involved at various degrees, and the type and severity of clefts vary. One of the longstanding questions is how environmental factors lead to craniofacial developmental anomalies. Recent studies highlight non-coding RNAs as potential epigenetic regulators in cleft lip and palate. In this review, we will discuss microRNAs, a type of small non-coding RNAs that can simultaneously regulate expression of many downstream target genes, as a causative mechanism of cleft lip and palate in humans and mice.

Effects of Intensive Glycemic Control on Serum Exosome miR-126-3p and miR-125b-1-3p Levels and Wound Healing in Patients with Diabetic Ulcers

Objective

Intensive glycemic control and exosomal miRNAs have both been reported to improve wound repair in diabetic ulcers. In this study, we aimed to investigate the effects of intensive glycemic control on serum exosome microRNA-126-3p (miR-126-3p), microRNA-125b-1-3p (miR-125b-1-3p), and wound healing in patients with diabetic ulcers.

Methods

Herein, 45 diabetic patients with an ulcer, aged 35-75 years old, were randomly assigned to the intensive glycemic control group (n = 21) and the conventional glycemic control group (n = 24). Serum exosomes were extracted in the laboratory and assessed by Western blotting, transmission electron microscopy, and nanoparticle tracking analysis. The expression of miR-126-3p and miR-125b-1-3p was validated using quantitative real-time polymerase chain reaction. The wound healing of each diabetic ulcer patient was measured and imaged; additionally, clinical and follow-up data were collected. Finally, the clinical and laboratory data were combined for statistical analysis.

Results

Intensive glycemic control was significantly more conducive to wound healing and infection control than conventional glycemic control (P < 0.05). Serum exosomal miR-126-3p was negatively correlated with fasting plasma glucose levels (r = 0.34, P < 0.05) and positively associated with the wound healing rate (r = 0.45, P < 0.01). The level of miR-126-3p in the intensive glycemic control group was significantly higher than that in the conventional glycemic control group (P < 0.01). Serum exosomal miR-125b-1-3p was not correlated with blood glucose levels (r = 0.03, P > 0.05) and was positively associated with the wound healing rate (r = 0.33, P < 0.05). No significant difference was observed in the level of miR-125b-1-3p between the intensive and conventional glycemic control groups. Regarding the prognosis of diabetic ulcers, the intensive glycemic control group was better than the conventional group (Z = -2.02, P < 0.05).

Conclusion

Serum exosome (miR-125b-1-3p and miR-126-3p) levels are correlated with wound healing in diabetic ulcers. Intensive glycemic control increases the serum exosomal miR-126-3p level, which might be one of the mechanisms that promotes wound healing in diabetic ulcers.

Effects of microRNAs on angiogenesis in diabetic wounds

Diabetes mellitus is a morbid condition affecting a growing number of the world population, and approximately one third of diabetic patients are afflicted with diabetic foot ulcers (DFU), which are chronic non-healing wounds that frequently progress to require amputation. The treatments currently used for DFU focus on reducing pressure on the wound, staving off infection, and maintaining a moist environment, but the impaired wound healing that occurs in diabetes is a constant obstacle that must be faced. Aberrant angiogenesis is a major contributor to poor wound healing in diabetes and surgical intervention is often necessary to establish peripheral blood flow necessary for healing wounds. Over recent years, microRNAs (miRNAs) have been implicated in the dysregulation of angiogenesis in multiple pathologies including diabetes. This review explores the pathways of angiogenesis that become dysregulated in diabetes, focusing on miRNAs that have been identified and the mechanisms by which they affect angiogenesis.

miRNAs as cornerstones in diabetic microvascular complications

Diabetes mellitus is usually accompanied by nephropathy, retinopathy, and neuropathy as microvascular complications. MicroRNAs (miRNAs) can affect the kidney, retina, and peripheral neurons through their implication in pathways involved in angiogenesis, inflammation, apoptosis, as well as fibrosis within these tissues and hence, play a crucial role in the pathogenesis of microvascular complications. In this review, the updated knowledge of the role of miRNAs in the pathogenesis of diabetic microvascular complications was summarized. PubMed Central was searched extensively to retrieve data from a wide range of reputable biomedical reports/articles published after the year 2000 to systematically collect and present a review of the key molecular pathways mediating the hyperglycemia-induced adverse effects on vascular tissues, particularly in persons with T2DM. In the present review, miR-126, miR-29b, and miR-125a are implicated in diabetes-induced microvascular complications, while miR-146a is found to be connected to all these complications. Also, vascular endothelial growth factors are noted to be the most impacted targets by miRNAs in all diabetic microvascular problems.

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.

Exosome-cargoed microRNAs: Potential therapeutic molecules for diabetic wound healing

Diabetic foot ulcers are one of the most common complications of diabetes, requiring repeated surgical intervention and leading to amputation. Owing to the lack of effective drugs, novel therapeutics need to be explored. Decreased angiogenic factors, endothelial cell dysfunction and vascular lumen stenosis impair angiogenesis in diabetic wounds. Exosome-cargoed microRNAs are emerging as pivotal regulators of angiogenesis during wound closure. Herein, we summarize the up-to-date knowledge of exosomal microRNAs in modulating angiogenesis and accelerating diabetic wound healing, as well as their targets and underlying mechanisms. Exosomal microRNAs could be therapeutics with negligible rejection complications and good compatibility to treat diabetic foot ulcers.

Phenformin suppresses angiogenesis through the regulation of exosomal microRNA-1246 and microRNA-205 levels derived from oral squamous cell carcinoma cells

Exosomes secreted by cancer cells are important components in the tumor microenvironment, enabling cancer cells to communicate with each other and with noncancerous cells to play important roles in tumor progression and metastasis. Phenformin, a biguanide antidiabetic drug, has been reported to have a strong antitumor function in multiple types of cancer cells, however little research has been reported about whether phenformin can regulate the secretion of exosomes by cancer cells to regulate the tumor microenvironment and contribute to its antitumor function. Here we found that exosomes (Phen-Exo) derived from phenformin-treated oral squamous cell carcinoma (OSCC) cells significantly suppress the proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) in vitro. The inhibition of angiogenesis by Phen-Exo was verified in vivo by matrigel plug angiogenesis assays and by chick chorioallantoic membrane assays. Mechanistically, we discovered that the expression of microRNA-1246 (miR-1246) and microRNA-205 (miR-205) was significantly increased in exosomes secreted by OSCC cells treated with phenformin, while high expression levels of miR-1246 or miR-205 in vascular endothelial cells inhibited their angiogenic effects and decreased expression of the angiogenic factor VEGFA. In conclusion, these results reveal that phenformin can inhibit angiogenesis by regulating the levels of miR-1246 and miR-205 in exosomes secreted by OSCC cells, suggesting that phenformin has the potential to alter the tumor microenvironment to antagonize the growth of OSCCs, which provides a theoretical basis for developing new strategies to treat OSCCs in the future.

miR-199a-5p Plays a Pivotal Role on Wound Healing via Suppressing VEGFA and ROCK1 in Diabetic Ulcer Foot

Diabetes mellitus (DM) is a growing health problem. As a common complication of DM, diabetic foot ulcer (DFU) results in delayed wound healing and is a leading cause of nontraumatic amputation. miR-199a-5p, a short noncoding RNA, had abnormal expression in DFU wound tissues. The expression of miR-199a-5p was significantly increased in DFU wound tissues, skin tissues of diabetic rats, and high glucose-induced cells. Vascular endothelial growth factor A (VEGFA) and Rho-associated kinase 1 (ROCK1) are directly targets of miR-199a-5p. Inhibiting the expression of miR-199a-5p alleviated the inhibition of VEGFA and ROCK1, thereby rescued impaired proliferation and migration of HG-induced cells, and restored the normal function of the cells to some extent. In diabetic rats, inhibition of miR-199a-5p significantly increased the expression of VEGFA and ROCK1, significantly promoted wound healing, and rescued impaired wound healing. miR-199a-5p and its targets showed therapeutic effect on diabetic wounds.

Research progress on the mechanism by which skin macrophage dysfunction mediates chronic inflammatory injury in diabetic skin

Macrophages, the main immune cells in the skin, form an innate immune barrier. Under physiological conditions, skin maintains immune barrier function through macrophage phagocytosis and antigen presentation. Parenchymal and stromal cell regeneration plays an important role in skin injury repair and uses macrophage plasticity to influence and stabilize the skin microenvironment. Diabetic skin lesions are the most common diabetes complication and are involved in the early pathophysiology of diabetic foot. Therefore, studying the initial link in diabetic skin lesions is a research hot spot in the early pathogenesis of diabetic foot. Skin inflammation caused by hyperglycaemia, oxidative stress and other injuries is an important feature, but the specific mechanism is unknown. Recent studies have suggested that chronic inflammatory injury is widely involved in a variety of skin diseases, and whether it plays an important role in diabetic skin lesions is unclear. In this review, current research hotspots were combined with the pathogenesis of diabetic skin lesions and analysed from the perspectives of the physiological function of skin macrophages, the impairment of skin macrophages in diabetes, and the mechanism of chronic inflammatory injury in macrophages to provide a theoretical basis for early screening and evaluation of diabetic foot.

The Utility of Exosomes in Diagnosis and Therapy of Diabetes Mellitus and Associated Complications

Diabetes mellitus and the associated complications are metabolic diseases with high morbidity that result in poor quality of health and life. The lack of diagnostic methods for early detection results in patients losing the best treatment opportunity. Oral hypoglycemics and exogenous insulin replenishment are currently the most common therapeutic strategies, which only yield temporary glycemic control rather than curing the disease and its complications. Exosomes are nanoparticles containing bioactive molecules reflecting individual physiological status, regulating metabolism, and repairing damaged tissues. They function as biomarkers of diabetes mellitus and diabetic complications. Considering that exosomes are bioactive molecules, can be obtained from body fluid, and have cell-type specificity, in this review, we highlight the multifold effects of exosomes in the pathology and therapy of diabetes mellitus and diabetic complications.