Regulation of impaired angiogenesis in diabetic dermal wound healing by microRNA-26a

Antioxidant Hydrogels: Antioxidant Mechanisms, Design Strategies, and Applications in the Treatment of Oxidative Stress-Related Diseases

Oxidative stress is a biochemical process that disrupts the redox balance due to an excess of oxidized substances within the cell. Oxidative stress is closely associated with a multitude of diseases and health issues, including cancer, diabetes, cardiovascular diseases, neurodegenerative disorders, inflammatory conditions, and aging. Therefore, the developing of antioxidant treatment strategies has emerged as a pivotal area of medical research. Hydrogels have garnered considerable attention due to their exceptional biocompatibility, adjustable physicochemical properties, and capabilities for drug delivery. Numerous antioxidant hydrogels have been developed and proven effective in alleviating oxidative stress. In the pursuit of more effective treatments for oxidative stress-related diseases, there is an urgent need for advanced strategies for the fabrication of multifunctional antioxidant hydrogels. Consequently, the authors' focus will be on hydrogels that possess exceptional reactive oxygen species and reactive nitrogen species scavenging capabilities, and their role in oxidative stress therapy will be evaluated. Herein, the antioxidant mechanisms and the design strategies of antioxidant hydrogels and their applications in oxidative stress-related diseases are discussed systematically in order to provide critical insights for further advancements in the field.

MicroRNA-409-3p/BTG2 signaling axis improves impaired angiogenesis and wound healing in obese mice

Wound healing is facilitated by neoangiogenesis, a complex process that is essential to tissue repair in response to injury. MicroRNAs are small, noncoding RNAs that can regulate the wound healing process including stimulation of impaired angiogenesis that is associated with type-2 diabetes (T2D). Expression of miR-409-3p was significantly increased in the nonhealing skin wounds of patients with T2D compared to the non-wounded normal skin, and in the skin of a murine model with T2D. In response to high glucose, neutralization of miR-409-3p markedly improved EC growth and migration in human umbilical vein endothelial cells (HUVECs), promoted wound closure and angiogenesis as measured by increased CD31 in human skin organoids, while overexpression attenuated EC angiogenic responses. Bulk mRNA-Seq transcriptomic profiling revealed BTG2 as a target of miR-409-3p, where overexpression of miR-409-3p significantly decreased BTG2 mRNA and protein expression. A 3' untranslated region (3'-UTR) luciferase assay of BTG2 revealed decreased luciferase activity with overexpression of miR-409-3p, while inhibition had opposite effects. Mechanistically, in response to high glucose, miR-409-3p deficiency in ECs resulted in increased mTOR phosphorylation, meanwhile BTG-anti-proliferation factor 2 (BTG2) silencing significantly decreased mTOR phosphorylation. Endothelial-specific and tamoxifen-inducible miR-409-3p knockout mice (MiR-409IndECKO ) with hyperglycemia that underwent dorsal skin wounding showed significant improvement of wound closure, increased blood flow, granulation tissue thickness (GTT), and CD31 that correlated with increased BTG2 expression. Taken together, our results show that miR-409-3p is a critical mediator of impaired angiogenesis in diabetic skin wound healing.

Insights into the mechanisms of diabetic wounds: pathophysiology, molecular targets, and treatment strategies through conventional and alternative therapies

Diabetes mellitus is a prevalent cause of mortality worldwide and can lead to several secondary issues, including DWs, which are caused by hyperglycemia, diabetic neuropathy, anemia, and ischemia. Roughly 15% of diabetic patient's experience complications related to DWs, with 25% at risk of lower limb amputations. A conventional management protocol is currently used for treating diabetic foot syndrome, which involves therapy using various substances, such as bFGF, pDGF, VEGF, EGF, IGF-I, TGF-β, skin substitutes, cytokine stimulators, cytokine inhibitors, MMPs inhibitors, gene and stem cell therapies, ECM, and angiogenesis stimulators. The protocol also includes wound cleaning, laser therapy, antibiotics, skin substitutes, HOTC therapy, and removing dead tissue. It has been observed that treatment with numerous plants and their active constituents, including Globularia Arabica, Rhus coriaria L., Neolamarckia cadamba, Olea europaea, Salvia kronenburgii, Moringa oleifera, Syzygium aromaticum, Combretum molle, and Myrtus communis, has been found to promote wound healing, reduce inflammation, stimulate angiogenesis, and cytokines production, increase growth factors production, promote keratinocyte production, and encourage fibroblast proliferation. These therapies may also reduce the need for amputations. However, there is still limited information on how to prevent and manage DWs, and further research is needed to fully understand the role of alternative treatments in managing complications of DWs. The conventional management protocol for treating diabetic foot syndrome can be expensive and may cause adverse side effects. Alternative therapies, such as medicinal plants and green synthesis of nano-formulations, may provide efficient and affordable treatments for DWs.

Analysis of Bulk Transcriptome Sequencing Data and in vitro Experiments Reveal SIN3A as a Potential Target for Diabetic Foot Ulcer

Background

Diabetic foot ulcers (DFUs) represent a severe complication of diabetes associated with reduced quality of life, lower limb amputations, hospitalizations, increased incidence, and mortality. Importantly, a significant number of pathogenic genes remain unexplored in DFUs.

Methods

A series of bioinformatics analyses were performed on publicly available bulk transcriptome sequencing datasets GSE134431 and GSE80178 to explore the transcriptomic changes in DFUs and select core genes for in vitro functional validation. In a focused examination, the differential expression analysis unveiled distinctions in gene expression patterns between DFUs and non-ulcerated diabetic skin tissues. Enriched functional annotations of differentially expressed genes were explored using the DAVID online tool. Protein-protein interaction analysis was conducted to investigate interactions among differentially expressed genes and select core genes. Knockdown or overexpression of core genes in HaCaT keratinocytes was performed to assess their impact on cell proliferation and migration.

Results

Ten core genes were identified. Cell Counting Kit-8 (CCK-8) and scratch assays demonstrated that downregulation of the core gene SIN3A significantly inhibited the migration and proliferation of HaCaT keratinocytes, while overexpression of SIN3A reversed the high-glucose-induced suppression of HaCaT cell viability and migration.

Conclusion

SIN3A expression is downregulated in DFUs. In vitro, SIN3A promotes the proliferation and migration of HaCaT keratinocytes, suggesting it may be a potential therapeutic target for DFUs.

Development of miR-26a-activated scaffold to promote healing of critical-sized bone defects through angiogenic and osteogenic mechanisms

Very large bone defects significantly diminish the vascular, blood, and nutrient supply to the injured site, reducing the bone's ability to self-regenerate and complicating treatment. Delivering nanomedicines from biomaterial scaffolds that induce host cells to produce bone-healing proteins is emerging as an appealing solution for treating these challenging defects. In this context, microRNA-26a mimics (miR-26a) are particularly interesting as they target the two most relevant processes in bone regeneration-angiogenesis and osteogenesis. However, the main limitation of microRNAs is their poor stability and issues with cytosolic delivery. Thus, utilising a collagen-nanohydroxyapatite (coll-nHA) scaffold in combination with cell-penetrating peptide (RALA) nanoparticles, we aimed to develop an effective system to deliver miR-26a nanoparticles to regenerate bone defects in vivo. The microRNA-26a complexed RALA nanoparticles, which showed the highest transfection efficiency, were incorporated into collagen-nanohydroxyapatite scaffolds and in vitro assessment demonstrated the miR-26a-activated scaffolds effectively transfected human mesenchymal stem cells (hMSCs) resulting in enhanced production of vascular endothelial growth factor, increased alkaline phosphatase activity, and greater mineralisation. After implantation in critical-sized rat calvarial defects, micro CT and histomorphological analysis revealed that the miR-26a-activated scaffolds improved bone repair in vivo, producing new bone of superior quality, which was highly mineralised and vascularised compared to a miR-free scaffold. This innovative combination of osteogenic collagen-nanohydroxyapatite scaffolds with multifunctional microRNA-26a complexed nanoparticles provides an effective carrier delivering nanoparticles locally with high efficacy and minimal off-target effects and demonstrates the potential of targeting osteogenic-angiogenic coupling using scaffold-based nanomedicine delivery as a new "off-the-shelf" product capable of healing complex bone injuries.

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.

The capacity of exosomes derived from adipose-derived stem cells to enhance wound healing in diabetes

The slow healing and nonhealing of diabetic wounds have long posed challenges for clinical practitioners. In the presence of elevated glucose levels, the body's regulatory mechanisms undergo alterations that impede normal wound healing processes, including cell proliferation, cytokine release, and growth factor activity. Consequently, the advancement of stem cell technology has sparked growing interest in utilizing stem cells and their derivatives as potential therapeutic agents to enhance diabetic wound healing. This paper aims to provide an academic review of the therapeutic effects of adipose-derived stem cell-EXOs (ADSC-EXOs) in diabetic wound healing. As a cell-free therapy, exosomes (EXOs) possess a multitude of proteins and growth factors that have been shown to be advantageous in promoting wound healing and mitigating the potential risks associated with stem cell therapy. By examining the current knowledge on ADSC-EXOs, this review seeks to offer insights and guidance for the potential application of EXOs in the treatment of diabetic wounds.

Electrostatically assembled wound dressings deliver pro-angiogenic anti-miRs preferentially to endothelial cells

Chronic non-healing wounds occur frequently in individuals affected by diabetes, yet standard-of-care treatment leaves many patients inadequately treated or with recurring wounds. MicroRNA (miR) expression is dysregulated in diabetic wounds and drives an anti-angiogenic phenotype, but miRs can be inhibited with short, chemically-modified RNA oligonucleotides (anti-miRs). Clinical translation of anti-miRs is hindered by delivery challenges such as rapid clearance and uptake by off-target cells, requiring repeated injections, excessively large doses, and bolus dosing mismatched to the dynamics of the wound healing process. To address these limitations, we engineered electrostatically assembled wound dressings that locally release anti-miR-92a, as miR-92a is implicated in angiogenesis and wound repair. In vitro, anti-miR-92a released from these dressings was taken up by cells and inhibited its target. An in vivo cellular biodistribution study in murine diabetic wounds revealed that endothelial cells, which play a critical role in angiogenesis, exhibit higher uptake of anti-miR eluted from coated dressings than other cell types involved in the wound healing process. In a proof-of-concept efficacy study in the same wound model, anti-miR targeting anti-angiogenic miR-92a de-repressed target genes, increased gross wound closure, and induced a sex-dependent increase in vascularization. Overall, this proof-of-concept study demonstrates a facile, translational materials approach for modulating gene expression in ulcer endothelial cells to promote angiogenesis and wound healing. Furthermore, we highlight the importance of probing cellular interactions between the drug delivery system and the target cells to drive therapeutic efficacy.

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.

Advances in Zebrafish for Diabetes Mellitus with Wound Model

Diabetic foot ulcers cause great suffering and are costly for the healthcare system. Normal wound healing involves hemostasis, inflammation, proliferation, and remodeling. However, the negative factors associated with diabetes, such as bacterial biofilms, persistent inflammation, impaired angiogenesis, inhibited cell proliferation, and pathological scarring, greatly interfere with the smooth progress of the entire healing process. It is this impaired wound healing that leads to diabetic foot ulcers and even amputations. Therefore, drug screening is challenging due to the complexity of damaged healing mechanisms. The establishment of a scientific and reasonable animal experimental model contributes significantly to the in-depth research of diabetic wound pathology, prevention, diagnosis, and treatment. In addition to the low cost and transparency of the embryo (for imaging transgene applications), zebrafish have a discrete wound healing process for the separate study of each stage, resulting in their potential as the ideal model animal for diabetic wound healing in the future. In this review, we examine the reasons behind the delayed healing of diabetic wounds, systematically review various studies using zebrafish as a diabetic wound model by different induction methods, as well as summarize the challenges and improvement strategies which provide references for establishing a more reasonable diabetic wound zebrafish model.

Preclinical evidence of polyherbal formulations on wound healing: A systematic review on research trends and perspectives

BACKGROUND

The disruptions in skin integrity contribute to its disorientation, and tissue annihilations result in acute or chronic wound formation. Polyherbal formulations are widely used in traditional systems of mecdicine like ayurveda for wound healing. The combination of these traditional therapies with clinical therapies has helped in the development of various wound-healing products.

METHOD

In this systematic review, the therapeutic potency of several polyherbal formulations from different medicinal floras is summed together in response to their impact on wound healing. The literature search was performed on Pubmed, Scopus, and ScienceDirect databases between 2010-2020. PRISMA methodology was applied to extract relevant information about polyherbal formulations.

RESULT

A total of 54 articles were selected under all themes for the data extraction as per the PRISMA guidelines. These 54 articles have high-quality scores ≥3. Forty-three records were used for the narrative analysis, while nine records were used for the critical analysis in the narrative review. Further, theme-wise key data sets were screened from the selected literature and summarized in a tabular form. Bibliometric analysis of the Scopus database has also drawn attention to limited academic literature showcasing randomized clinical trials in the current subject. Most of these polyherbal formulations are tested in laboratory-scale studies, thus portraying further research options.

CONCLUSION

Polyherbal formulations are effective in promoting the wound-healing process. They can stimulate a variety of physiological functions that accelerates the process of healing. These formulations merit further investigation in clinical trials, and production up scaling will aid in the creation of a new horizon of polyherbal wound healing products.

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.

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.

Autophagic reprogramming of bone marrow–derived macrophages

Macro-autophagy is a highly conserved catabolic process among eukaryotes affecting macrophages. This work studies the genetic regulatory network involving the interplay between autophagy and macrophage polarization (activation). Autophagy-related genes (Atgs) and differentially expressed genes (DEGs) of macrophage polarization (M1–M2) were predicted, and their regulatory networks constructed. Naïve (M0) mouse bone marrow–derived monocytes were differentiated into M1 and M2a. Validation of the targets of Smad1, LC3A and LC3B, Atg16L1, Atg7, IL-6, CD68, Arg-1, and Vamp7 was performed in vitro. Immunophenotyping by flow cytometry revealed three macrophage phenotypes: M0 (IL-6 + /CD68 +), M1 (IL-6 + /CD68 + /Arg-1 +), and M2a (CD68 + /Arg-1). Confocal microscopy revealed increased autophagy in both M1 and M2a and a significant increase in the pre-autophagosomes size and number. Bafilomycin A increased the expression of CD68 and Arg-1 in all cell lineages. In conclusion, our approach predicted the protein targets mediating the interplay between autophagy and macrophage polarization. We suggest that autophagy reprograms macrophage polarization via CD68, arginase 1, Atg16L1-1, and Atg16L1-3. The current findings provide a foundation for the future use of macrophages in immunotherapy of different autoimmune disorders.

[Latest Findings on MicroRNAs in Diabetic Chronic Wounds]

Diabetic chronic wound is one of the most serious complications of diabetes, imposing enormous socioeconomic burdens on diabetic patients, their families, and society due to its refractory nature. MicroRNAs (miRNAs) have emerged as important regulators of various physiological and pathological processes. Abnormalities arise in the regulatory functions of miRNAs in chronic diabetic wounds. Therefore, the modification of miRNAs expression in diabetic wounds is an important channel for the improvement of wound healing. The clinical translation of miRNA-based therapy may become a prospective direction of diabetic wound healing. However, miRNA-based therapy is still in its early stage of development, and actual translation into clinical application will take a long time. Herein, we summarized the latest research findings on miRNAs in diabetic chronic wounds healing.

Use of Optical Coherence Tomography (OCT) in Assessment of Diabetic Skin Wound Characteristics and Blood Flow

Optical coherence tomography allows for various measurements of skin but the utility of the device in determining properties of normal and wounded skin in diabetic patients is unknown. This single-site, non-randomized, observational study used an optical coherence tomography device to acquire skin images at 1305 nm, creating real-time image of 17 patient's skin and wounds 1 to 2 mm under the skin surface. Vertical B-scan, en-face and 3-D images were produced to calculate surface and dermal-epidermal junction roughness, the optical attenuation coefficient, a measure of light absorption and scattering, and blood flow metrics. In subjects with diabetes there was an increase in both the Ra (p < .02) and Rz (p < .001) of the wounded versus the control skin. In subjects without diabetes, there was an increase in both the Ra (p < .001) and Rz (p < .03) values of the wounded versus the control skin. At a depth of 0.6 mm across all subjects, there was an average decrease in blood flow of 63% from control to wounded skin. In subjects with diabetes, this decrease was 76%. In subjects without diabetes the decrease was 55%. The change in vasculature between control and wounded skin was associated with a p < .005. There was an increase in the Ra and Rz values and a decrease in blood flow between the wounded skin and control. The device determined a difference in the Ra and Rz values of both diabetic and healthy subjects' skin and a more pronounced decrease in blood flow in the wounds of patients with diabetes as opposed to those without.

Gene therapy to enhance angiogenesis in chronic wounds

Skin injuries and chronic non-healing wounds are one of the major global burdens on the healthcare systems worldwide due to their difficult-to-treat nature, associated co-morbidities, and high health care costs. Angiogenesis has a pivotal role in the wound-healing process, which becomes impaired in many chronic non-healing wounds, leading to several healing disorders and complications. Therefore, induction or promotion of angiogenesis can be considered a promising approach for healing of chronic wounds. Gene therapy is one of the most promising upcoming strategies for the treatment of chronic wounds. It can be classified into three main approaches: gene augmentation, gene silencing, and gene editing. Despite the increasing number of encouraging results obtained using nucleic acids (NAs) as active pharmaceutical ingredients of gene therapy, efficient delivery of NAs to their site of action (cytoplasm or nucleus) remains a key challenge. Selection of the right therapeutic cargo and delivery methods is crucial for a favorable prognosis of the healing process. This article presents an overview of gene therapy and non-viral delivery methods for angiogenesis induction in chronic wounds.

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.

Wound Healing Impairment in Type 2 Diabetes Model of Leptin-Deficient Mice—A Mechanistic Systematic Review

Type II diabetes mellitus (T2DM) is one of the most prevalent diseases in the world, associated with diabetic foot ulcers and impaired wound healing. There is an ongoing need for interventions effective in treating these two problems. Pre-clinical studies in this field rely on adequate animal models. However, producing such a model is near-impossible given the complex and multifactorial pathogenesis of T2DM. A leptin-deficient murine model was developed in 1959 and relies on either dysfunctional leptin (ob/ob) or a leptin receptor (db/db). Though monogenic, this model has been used in hundreds of studies, including diabetic wound healing research. In this study, we systematically summarize data from over one hundred studies, which described the mechanisms underlying wound healing impairment in this model. We briefly review the wound healing dynamics, growth factors’ dysregulation, angiogenesis, inflammation, the function of leptin and insulin, the role of advanced glycation end-products, extracellular matrix abnormalities, stem cells’ dysregulation, and the role of non-coding RNAs. Some studies investigated novel chronic diabetes wound models, based on a leptin-deficient murine model, which was also described. We also discussed the interventions studied in vivo, which passed into human clinical trials. It is our hope that this review will help plan future research.

Oxidative Stress and Lipid Peroxidation: Prospective Associations Between Ferroptosis and Delayed Wound Healing in Diabetic Ulcers

Diabetic ulcers are one of the major complications of diabetes, and patients usually suffer from amputation and death due to delayed ulcer wound healing. Persistent inflammation and oxidative stress at the wound site are the main manifestations of delayed wound healing in diabetic ulcers. In addition, chronic hyperglycemia in patients can lead to circulatory accumulation of lipid peroxidation products and impaired iron metabolism pathways leading to the presence of multiple free irons in plasma. Ferroptosis, a newly discovered form of cell death, is characterized by intracellular iron overload and accumulation of iron-dependent lipid peroxides. These indicate that ferroptosis is one of the potential mechanisms of delayed wound healing in diabetic ulcers and will hopefully be a novel therapeutic target for delayed wound healing in diabetic patients. This review explored the pathogenesis of diabetic ulcer wound healing, reveals that oxidative stress and lipid peroxidation are common pathological mechanisms of ferroptosis and delayed wound healing in diabetic ulcers. Based on strong evidence, it is speculated that ferroptosis and diabetic ulcers are closely related, and have value of in-depth research. We attempted to clarify prospective associations between ferroptosis and diabetic ulcers in terms of GPX4, iron overload, ferroptosis inhibitors, AGEs, and HO-1, to provide new ideas for exploring the clinical treatment of diabetic ulcers.

State-of-the-Art on Wound Vitality Evaluation: A Systematic Review

The vitality demonstration refers to determining if an injury has been caused ante- or post-mortem, while wound age means to evaluate how long a subject has survived after the infliction of an injury. Histology alone is not enough to prove the vitality of a lesion. Recently, immunohistochemistry, biochemistry, and molecular biology have been introduced in the field of lesions vitality and age demonstration. The study was conducted according to the preferred reporting items for systematic review (PRISMA) protocol. The search terms were "wound", "lesion", "vitality", "evaluation", "immunohistochemistry", "proteins", "electrolytes", "mRNAs", and "miRNAs" in the title, abstract, and keywords. This evaluation left 137 scientific papers. This review aimed to collect all the knowledge on vital wound demonstration and provide a temporal distribution of the methods currently available, in order to determine the age of lesions, thus helping forensic pathologists in finding a way through the tangled jungle of wound vitality evaluation.

Extracellular vesicles enriched with an endothelial cell pro-survival microRNA affects skin tissue regeneration

Endothelial cell (EC) activity is essential for tissue regeneration in several (patho)physiological contexts. However, our capacity to deliver in vivo biomolecules capable of controlling EC fate is relatively limited. Here, we screened a library of microRNA (miR) mimics and identified 25 miRs capable of enhancing the survival of ECs exposed to ischemia-mimicking conditions. In vitro, we showed that miR-425-5p, one of the hits, was able to enhance EC survival and migration. In vivo, using a mouse Matrigel plug assay, we showed that ECs transfected with miR-425-5p displayed enhanced survival compared with scramble-transfected ECs. Mechanistically, we showed that miR-425-5p modulated the PTEN/PI3K/AKT pathway and inhibition of miR-425-5p target genes (DACH1, PTEN, RGS5, and VASH1) phenocopied the pro-survival. For the in vivo delivery of miR-425-5p, we modulated small extracellular vesicles (sEVs) with miR-425-5p and showed, in vitro, that miR-425-5p-modulated sEVs were (1) capable of enhancing the survival of ECs exposed to ischemia-mimic conditions, and (2) efficiently internalized by skin cells. Finally, using a streptozotocin-induced diabetic wound healing mouse model, we showed that, compared with miR-scrambled-modulated sEVs, topical administration of miR-425-5p-modulated sEVs significantly enhanced wound healing, a process mediated by enhanced vascularization and skin re-epithelialization.

Therapeutic delivery of nucleic acids for skin wound healing

Though wound care has advanced, treating chronic wounds remains a challenge and there are many clinical issues that must be addressed. Gene therapy is a recent approach to treating chronic wounds that remains in its developmental stage. The limited reports available describe the therapeutic applications of various forms of nucleic acid delivery for treating chronic wounds, including DNA, mRNA, siRNA, miRNA and so on. Though these bioactive molecules represent great therapeutic potential, sustaining their bioactivity in the wound bed is a challenge. To overcome this hurdle, delivery systems are also being widely investigated. In this review, nucleic acid-based therapy and its delivery for treating chronic wounds is discussed in detail.

A time to heal: microRNA and circadian dynamics in cutaneous wound repair

Many biological systems have evolved circadian rhythms based on the daily cycles of daylight and darkness on Earth. Such rhythms are synchronised or entrained to 24-h cycles, predominantly by light, and disruption of the normal circadian rhythms has been linked to elevation of multiple health risks. The skin serves as a protective barrier to prevent microbial infection and maintain homoeostasis of the underlying tissue and the whole organism. However, in chronic non-healing wounds such as diabetic foot ulcers (DFUs), pressure sores, venous and arterial ulcers, a variety of factors conspire to prevent wound repair. On the other hand, keloids and hypertrophic scars arise from overactive repair mechanisms that fail to cease in a timely fashion, leading to excessive production of extracellular matrix (ECM) components such as such as collagen. Recent years have seen huge increases in our understanding of the functions of microRNAs (miRNAs) in wound repair. Concomitantly, there has been growing recognition of miRNA roles in circadian processes, either as regulators or targets of clock activity or direct responders to external circadian stimuli. In addition, miRNAs are now known to function as intercellular signalling mediators through extracellular vesicles (EVs). In this review, we explore the intersection of mechanisms by which circadian and miRNA responses interact with each other in relation to wound repair in the skin, using keratinocytes, macrophages and fibroblasts as exemplars. We highlight areas for further investigation to support the development of translational insights to support circadian medicine in the context of these cells.

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.

Possible roles of anti-type II collagen antibody and innate immunity in the development and progression of diabetic retinopathy

The pathogenesis of both diabetic retinopathy (DR) and rheumatoid arthritis (RA) has recently been considered to involve autoimmunity. Serum and synovial fluid levels of anti-type II collagen antibodies increase early after the onset of RA, thus inducing immune responses and subsequent hydrarthrosis and angiogenesis, which resemble diabetic macular edema and proliferative DR (PDR), respectively. We previously reported that DR is also associated with increased serum levels of anti-type II collagen antibodies. Retinal hypoxia in DR may induce pericytes to express type II collagen, resulting in autoantibody production against type II collagen. As the result of blood-retinal barrier disruption, anti-type II collagen antibodies in the serum come into contact with type II collagen around the retinal vessels. A continued loss of pericytes and type II collagen around the retinal vessels may result in a shift of the immune reaction site from the retina to the vitreous. It has been reported that anti-inflammatory M2 macrophages increased in the vitreous of PDR patients, accompanied by the activation of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a key regulator of innate immunity. M2 macrophages promote angiogenesis and fibrosis, which might be exacerbated and prolonged by dysregulated innate immunity.

Novel therapeutic targets for diabetes-related wounds or ulcers: an update on preclinical and clinical research

INTRODUCTION

Diabetes-related wounds, particularly diabetes-related foot ulcers, are mainly caused by lack of foot sensation and high plantar tissue stress secondary to peripheral neuropathy, ischemia secondary to peripheral artery disease, and dysfunctional wound healing. Current management of diabetes-related wounds involves the offloading of high foot pressures and the treatment of ischemia through revascularization. Despite these treatments, the global burden of diabetes-related wounds is growing, and thus, novel therapies are needed. The normal wound healing process is a coordinated remodeling process orchestrated by fibroblasts, endothelial cells, phagocytes, and platelets, controlled by an array of growth factors. In diabetes-related wounds, these coordinated processes are dysfunctional. The past animal model and human research suggest that prolonged wound inflammation, failure to adequately correct ischemia, and impaired wound maturation are key therapeutic targets to improve diabetes-related wound healing.

AREAS COVERED

This review summarizes recent preclinical and clinical research on novel diabetes-related wound treatments. Animal models of diabetes-related wounds and recent studies testing novel therapeutic agents in these models are described. Findings from clinical trials are also discussed. Finally, challenges to identifying and implementing novel therapies are described.

EXPERT OPINION

Given the growing volume of promising drug therapies currently under investigation, it is expected within the next decade, that diabetes-related wound treatment will be transformed.

Improvement of Chronic Wound Healing by Pre-activated Bone Marrow Cells with Sodium Nitroprusside in Rabbits

AIM OF STUDY

This study investigated whether pre-activated bone marrow cells with sodium nitro prusside have effectiveness in the inhibition of diabetic wound healing in diabetic rabbits. In diabetic skin disorders and conditions involved redox state disturbances. The aim was to determine the effect of two minimum dosages of sodium nitro prusside, and its' potential with bone marrow cells for chronic wound healing in-vivo.

METHODS

Full-thickness skin dorsal wounds were created on diabetic rabbits. The effects of two minimum concentrations of sodium nitro prusside solution with bone marrow cells on wound healing were studied. The useful combination of sodium nitro prusside with bone marrow cells on wound repair may be attributed to its functional influences on inflammation, angiogenesis, cell proliferation, matrix deposition, and remodeling.

RESULTS

The in-vivo experiments confirmed that pre-activated bone marrow cells contributed to wound healing by alleviating oxidative stress, increasing proliferation and migration, decreasing apoptosis. In histological results, improved collagen deposition, enhanced re-epithelization, angiogenesis, and decreased inflammatory infiltration were also detected in wound biopsies.

CONCLUSIONS

For the treatment of chronic wounds, cell-based therapy was an attractive approach. Bone marrow cells have a low ability to differentiate various types of cells or late healing without pretreatment. So it was needed to increase their potency of differentiation. The transplantation of pretreated bone marrow cells with a prime quantity of sodium nitro prusside solution improved chronic wound healing with a greater level of growth factors and a minimum level of oxidative stress.

Approaches to Modulate the Chronic Wound Environment Using Localized Nucleic Acid Delivery

Significance: Nonhealing wounds have been the subject of decades of basic and clinical research. Despite new knowledge about the biology of impaired wound healing, little progress has been made in treating chronic wounds, leaving patients with few therapeutic options. Diabetic ulcers are a particularly common form of nonhealing wound. Recent Advances: Recently, investigation of therapeutic nucleic acids (TNAs), including plasmid DNA, small interfering RNA, microRNA mimics, anti-microRNA oligonucleotides, messenger RNA, and antisense oligonucleotides, has created a new treatment strategy for chronic wounds. TNAs can modulate the wound toward a prohealing environment by targeting gene pathways associated with inflammation, proteases, cell motility, angiogenesis, epithelialization, and oxidative stress. A variety of delivery systems have been investigated for TNAs, including dendrimers, lipid nanoparticles (NPs), polymeric micelles, polyplexes, metal NPs, and hydrogels. This review summarizes recent developments in TNA delivery for therapeutic targets associated with chronic wounds, with an emphasis on diabetic ulcers. Critical Issues: Translational potential of TNAs remains a key challenge; we highlight some drug delivery approaches for TNAs that may hold promise. We also describe current commercial efforts to locally deliver nucleic acids to modulate the wound environment. Future Directions: Localized nucleic acid delivery holds promise for the treatment of nonhealing chronic wounds. Future efforts to improve targeting of these nucleic acid therapies in the wound with both spatial and temporal control through drug delivery systems will be crucial to successful clinical translation.

Capturing the RNA castle: Exploiting MicroRNA inhibition for wound healing

The growing pipelines of RNA-based therapies herald new opportunities to deliver better patient outcomes for complex disorders such as chronic nonhealing wounds associated with diabetes. Members of the microRNA (miRNA) family of small noncoding RNAs have emerged as targets for diverse elements of cutaneous wound repair, and both miRNA enhancement with mimics or inhibition with antisense oligonucleotides represent tractable approaches for miRNA-directed wound healing. In this review, we focus on miRNA inhibition strategies to stimulate skin repair given advances in chemical modifications to enhance the performance of antisense miRNA (anti-miRs). We first explore miRNAs whose inhibition in keratinocytes promotes keratinocyte migration, an essential part of re-epithelialisation during wound repair. We then focus on miRNAs that can be targeted for inhibition in endothelial cells to promote neovascularisation for wound healing in the context of diabetic mouse models. The picture that emerges is that direct comparisons of different anti-miRNAs modifications are required to establish the most translationally viable options in the chronic wound environment, that direct comparisons of the impact of inhibition of different miRNAs are needed to quantify and rank their relative efficacies in promoting wound repair, and that a standardised human ex vivo model of the diabetic wound is needed to reduce reliance on mouse models that do not necessarily enhance mechanistic understanding of miRNA-targeted wound healing.

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.

Anti-inflammation biomaterial platforms for chronic wound healing

Nowadays, there has been an increase in the number of people with chronic wounds, which has resulted in serious health problems worldwide. The rate-limiting stage of chronic wound healing has been found to be the inflammation stage, and strategies for shortening the prolonged inflammatory response have proven to be effective for increasing the healing rate. Recently, various anti-inflammatory strategies (such as anti-inflammatory drugs, antioxidant, NO regulation, antibacterial, immune regulation and angiogenesis) have attracted attention as potential therapeutic pathways. Moreover, various biomaterial platforms based on anti-inflammation therapy strategies have also emerged in the spotlight as potential therapies to accelerate the repair of chronic wounds. In this review, we systematically investigated the advances of various biomaterial platforms based on anti-inflammation strategies for chronic wound healing, to provide valuable guidance for future breakthroughs in chronic wound treatment.

Serum exosomes accelerate diabetic wound healing by promoting angiogenesis and ECM formation

Nonhealing wounds in diabetes remain a global clinical and research challenge. Exosomes are primary mediators of cell paracrine action, which are shown to promote tissue repair and regeneration. In this study, we investigated the effects of serum derived exosomes (Serum-Exos) on diabetic wound healing and its possible mechanisms. Serum-Exos were isolated from blood serum of normal healthy mice and identified by transmission electron microscopy and western blot. The effects of Serum-Exos on diabetic wound healing, fibroblast growth and migration, angiogenesis and extracellular matrix (ECM) formation were investigated. Our results showed that the isolated Serum-Exos exhibited a sphere-shaped morphology with a mean diameter at 150 nm, and expressed classical markers of exosomes including HSP70, TSG101, and CD63. Treatment with Serum-Exos elevated the percentage of wound closure and shortened the time of healing in diabetic mice. Mechanistically, Serum-Exos promoted granulation tissue formation and increased the expression of CD31, fibronectin and collagen-ɑ in diabetic mice. Serum-Exos also promoted the migration of NIH/3T3 cells, which was associated with increased expression levels of PCNA, Ki67, collagen-α and fibronectin. In addition, Serum-Exos enhanced tube formation in human umbilical vein endothelial cells and induced the expression of CD31 at both protein and messenger RNA levels. Collectively, our results suggest that Serum-Exos may facilitate the wound healing in diabetic mice by promoting angiogenesis and ECM formation, and show the potential application in treating diabetic wounds.

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.

MicroRNA-26a inhibits wound healing through decreased keratinocytes migration by regulating ITGA5 through PI3K/AKT signaling pathway

Background: Keratinocyte migration is essential for skin wound healing and recent studies demonstrated that microRNAs (miRNAs) are involved in the differentiation, migration and apoptosis in keratinocytes. However, the function of miR-26a in wound healing remains to be largely explored.

Methods: Northern blot and quantitative reverse transcriptase PCR (qRT-PCR) were used to detect the miR-26a expression and Western blot was used to detect integrin α-5 (ITGA5), phosphatidylinositol-3-kinase (PI3K), p-PI3K, protein kinase B (AKT) and p-AKT protein expression in immortalized human keratinocyte cell line HaCaT and normal human epidermal keratinocytes (NHEK) after 2 ng/ml transforming growth factor-β1 (TGF-β1) treatment for 0, 6, 12 and 24 h. Transwell assay and Wound healing assay were introduced to measure the cell migration of HaCaT cells. TargetScan online database, luciferase reporter assay and RNA immunoprecipitation (RIP) were employed to confirm the relationship between miR-26a and ITGA5.

Results: The RNA expression of miR-26a was down-regulated and ITGA5 protein expression was up-regulated by TGF-β1 treatment in HaCaT and NHEK cells in a time-dependent manner. MiR-26a overexpression inhibited the migration of HaCaT cells induced by TGF-β1 while miR-26a inhibitor enhanced the migration. ITGA5 was a downstream target mRNA and regulated by miR-26a. ITGA5 overexpression reversed the inhibitory effect of miR-26a on migration in HaCaT, while ITGA5 knockdown attenuated the stimulative effect of miR-26a inhibitor in HaCaT via PI3K/AKT signaling pathway.

Conclusion: MiR-26a overexpression inhibited TGF-β1 induced HaCaT cells migration via down-regulating ITGA5 through activating the PI3K/AKT signaling pathway.

Evaluation of the efficacy of platelet-rich plasma on healing of clean diabetic foot ulcers: A randomized clinical trial in Tehran, Iran

BACKGROUND AND AIMS

Diabetic foot ulcers (DFUs) are among challenging hurdles both for the patient and the physician. There is a recent trend toward finding novel and clinically efficient modalities to treat this potentially hazardous complication of diabetes mellitus in a timely manner. Herein, we aim to appraise the efficacy of platelet-rich plasma (PRP) in healing of clean DFUs.

METHODS

90 patients with clean DFUs consisting of 56 (62.2%) males and 34 (37.8%) females with mean age (±standard deviation) of 56.52 (±7.14) years were enrolled in this study between June 2017 and December 2018. They were randomly allocated into control group (47 patients who received conventional dressing along with silver sulfadiazine ointment twice daily), and case group (43 patients who received PRP gel twice weekly for 3 weeks). All the patients were followed up for 6 months.

RESULTS

Our study showed that PRP significantly increased the healing rate of DFUs regardless of the age (p-value: 0.0), gender (p-value: 0.0), or smoking (p-value: 0.0) and blood pressure (p-value: 0.0) status of patients, but it did not have a significant impact on the need for amputation (p-value: 0.11), level of amputation (p-value: 0.16), or the need for further treatments such as graft or angioplasty (p-value: 0.52).

CONCLUSION

Regardless of the age, gender, or smoking and blood pressure status of patients, PRP can be efficiently used in diabetic patients to accelerate the healing rate of foot ulcers.

Potential Applications of Nanomaterials and Technology for Diabetic Wound Healing

Diabetic wound shows delayed and incomplete healing processes, which in turn exposes patients to an environment with a high risk of infection. This article has summarized current developments of nanoparticles/hydrogels and nanotechnology used for promoting the wound healing process in either diabetic animal models or patients with diabetes mellitus. These nanoparticles/hydrogels promote diabetic wound healing by loading bioactive molecules (such as growth factors, genes, proteins/peptides, stem cells/exosomes, etc.) and non-bioactive substances (metal ions, oxygen, nitric oxide, etc.). Among them, smart hydrogels (a very promising method for loading many types of bioactive components) are currently favored by researchers. In addition, nanoparticles/hydrogels can be combined with some technology (including PTT, LBL self-assembly technique and 3D-printing technology) to treat diabetic wound repair. By reviewing the recent literatures, we also proposed new strategies for improving multifunctional treatment of diabetic wounds in the future.

Molecular complexities underlying the vascular complications of diabetes mellitus - A comprehensive review

Diabetes is a chronic disease, characterized by hyperglycemia, which refers to the elevated levels of glucose in the blood, due to the inability of the body to produce or use insulin effectively. Chronic hyperglycemia levels lead to macrovascular and microvascular complications. The macrovascular complications consist of peripheral artery disease (PAD), cardiovascular diseases (CVD) and cerebrovascular diseases, while the microvascular complications comprise of diabetic microangiopathy, diabetic nephropathy, diabetic retinopathy and diabetic neuropathy. Vascular endothelial dysfunction plays a crucial role in mediating both macrovascular and microvascular complications under hyperglycemic conditions. In diabetic microvasculature, the intracellular hyperglycemia causes damage to the vascular endothelium through - (i) activation of four biochemical pathways, namely the Polyol pathway, protein kinase C (PKC) pathway, advanced glycation end products (AGE) pathway and hexosamine pathway, all of which commutes glucose and its intermediates leading to overproduction of reactive oxygen species, (ii) dysregulation of growth factors and cytokines, (iii) epigenetic changes which concern the changes in DNA as a response to intracellular changes, and (iv) abnormalities in non-coding RNAs, specifically microRNAs. This review will focus on gaining an understanding of the molecular complexities underlying the vascular complications in diabetes mellitus, to increase our understanding towards the development of new mechanistic therapeutic strategies to prevent or treat diabetes-induced vascular complications.

Expression Profiling and Functional Characterization of miR-26a and miR-130a in Regulating Zhongwei Goat Hair Development via the TGF-β/SMAD Pathway

The Zhongwei goat is an important and unique goat breed indigenous to China. It has a natural hair curling phenotype at birth, but the degree of curling gradually decreases with growth. The molecular mechanism underlying the dynamic changes in the wool curvature in Zhongwei goats is poorly understood. MicroRNAs (miRNAs) play important roles in many biological processes, including hair growth and development. In this study, we selected skins from Zhongwei goats at different ages (45 and 108 days) that exhibited different levels of hair curvature and performed miRNA sequencing to explore the molecular mechanism of hair bending. In total, 28 significantly differentially expressed miRNAs (DE miRNAs) were identified in the three groups of samples between the two developmental stages. An analysis of the target genes of the above-mentioned DE miRNAs by the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses indicated that the DE miRNAs were involved in signal pathways which were previously associated with hair bending and hair follicle development, such as the TGF-β/SMAD, PI3K-Akt, JAK-STAT, and MAPK pathways. A comprehensive analysis of the correlations between the miRNA-seq results and issued transcriptional findings indicated that SMAD1 was a target gene of miR-26a and SMAD5 was a target gene of miR-130a. Furthermore, goat dermal papilla cells were successfully isolated and purified to determine the role of miRNAs in follicle development in vitro. The study results demonstrated that miR-130a and miR-26a had significant effects on the proliferation of dermal papilla cells. In addition, the detection results of mRNA and protein levels indicate that the overexpression of miR-26a can promote the expression of related genes in the TGF-β/SMAD pathway, while miR-130a has the opposite substitution effect. The dual luciferase report test showed that miR-26a targeted the SMAD1 gene and reduced the expression of the SMAD1 protein in hair papillary cells. Our results identified DE microRNAs which perhaps change at the time of hair straightening in Zhongwei goats and explore the role of miR-26a and miR-130a in dermal papilla cells proliferation. The present study provided a theoretical basis to explore the mechanisms underlying the Zhongwei hair growth and curly phenotype.

Natural SIRT1 modifiers as promising therapeutic agents for improving diabetic wound healing

BACKGROUND

The occurrence of chronic wounds, account for significant suffering of diabetic people, together with increasing healthcare burden. The chronic wounds associated with diabetes do not undergo the normal healing process rather stagnate into chronic proinflammatory phase as well as declined fibroblast function and impaired cell migration.

HYPOTHESIS

SIRT1, which is the most studied isoform of the sirtuin family in mammals, has now emerged as a crucial target for improving diabetic wound healing. It is an NAD+ dependent deacetylase, originally characterized to deacetylate histone proteins leading to heterochromatin formation and gene silencing. It is now known to regulate a number of cellular processes like cell proliferation, division, senescence, apoptosis, DNA repair, and metabolism.

METHODOLOGY

The retrieval of potentially relevant studies was done by systematically searching of three databases (Google Scholar, Web of science and PubMed) in December 2019. The keywords used as search terms were related to SIRT1 and wound healing. The systematic search retrieved 649 papers that were potentially relevant and after selection procedure, 73 studies were included this review and discussed below.

RESULTS

Many SIRT1 activating compounds (SACs) were found protective and improve diabetic wound healing through regulation of inflammation, cell migration, oxidative stress response and formation of granulation tissue at the wound site.

CONCLUSIONS

However, contradictory reports describe the opposing role of SACs on the regulation of cell migration and cancer incidence. SACs are therefore subjected to intense research for understanding the mechanisms responsible for controlling cell migration and therefore possess prospective to enter the clinical arena in the foreseeable future.

MiR-23b Promotes the Migration of Keratinocytes Through Downregulating TIMP3

BACKGROUND

Wound healing is a complex process aiming at repairing the damaged skin. MiR-23b has been reported to be upregulated during wound healing. In this study, we intended to explore the working mechanism of miR-23b during wound healing.

METHODS

Quantitative real-time polymerase chain reaction was performed to detect the enrichment of miR-23b and tissue inhibitor of metalloproteinase-3 (TIMP3) in HaCaT cells. Scratch wound assay was carried out to measure the migration of HaCaT cells. The target of miR-23b was predicted by microT-CDS software, and the combination was confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay. The abundance of TIMP3 protein was detected by Western blot assay.

RESULTS

The abundance of miR-23b was positively related to the concentration and time of transforming growth factor β1 treatment in HaCaT cells. MiR-23b promoted the migration of keratinocytes. TIMP3 was a direct target of miR-23b and was negatively regulated by miR-23b. TIMP3 inhibited the migration of keratinocytes. MiR-23b accelerated the migration of keratinocytes by downregulating the abundance of TIMP3.

CONCLUSIONS

MiR-23b promoted the migration of keratinocytes partly through reducing the enrichment of TIMP3. MiR-23b might be a promising target for the treatment of wound healing-associated diseases.

PC4 serves as a negative regulator of skin wound healing in mice

Background

Human positive cofactor 4 (PC4) was initially characterized as a multifunctional transcriptional cofactor, but its role in skin wound healing is still unclear. The purpose of this study was to explore the role of PC4 in skin wound healing through PC4 knock-in mouse model.

Methods

A PC4 knock-in mouse model (PC4^+/+) with a dorsal full-thickness wound was used to investigate the biological functions of PC4 in skin wound healing. Quantitative PCR, Western blot analysis and immunohistochemistry were performed to evaluate the expression of PC4; Sirius red staining and immunofluorescence were performed to explore the change of collagen deposition and angiogenesis. Proliferation and apoptosis were detected using Ki67 staining and TUNEL assay. Primary dermal fibroblasts were isolated from mouse skin to perform cell scratch experiments, cck-8 assay and colony formation assay.

Results

The PC4^+/+ mice were fertile and did not display overt abnormalities but showed an obvious delay in cutaneous healing of dorsal skin. Histological staining showed insufficient re-epithelialization, decreased angiogenesis and collagen deposition, increased apoptosis and decreased cell proliferation in PC4^+/+ skin. Our data also showed decreased migration rate and proliferation ability in cultured primary fibroblasts from PC4^+/+ mice in vitro.

Conclusions

This study suggests that PC4 might serve as a negative regulator of skin wound healing in mice.

MiR-4674 regulates angiogenesis in tissue injury by targeting p38K signaling in endothelial cells

Neoangiogenesis is critical for tissue repair in response to injury such as myocardial ischemia or dermal wound healing. MicroRNAs are small noncoding RNAs and important regulators of angiogenesis under physiological and pathological disease states. Therefore, identification of microRNAs that may restore impaired angiogenesis in response to tissue injury may provide new targets for therapy. Using a microRNA microarray profiling approach, we identified a human-specific microRNA, miR-4674, that was significantly decreased in patients after myocardial tissue injury and had an endothelial cell (EC)-enriched expression pattern. Functionally, overexpression of miR-4674 markedly attenuated EC proliferation, migration, network tube formation, and spheroid sprouting, whereas blockade of miR-4674 had the opposite effects. Transcriptomic profiling, gene set enrichment analyses, bioinformatics, 3'-untranslated region (3'-UTR) reporter and microribonucleoprotein immunoprecipitation (miRNP-IP) assays, and small interfering RNA dependency studies revealed that miR-4674 regulates VEGF stimulated-p38 mitogen-activated protein kinase (MAPK) signaling and targets interleukin 1 receptor-associated kinase 1 (Irak1) and BICD cargo adaptor 2 (Bicd2) in ECs. Furthermore, Irak1 and Bicd2 were necessary for miR-4674-driven EC proliferation and migration. Finally, neutralization of miR-4674 increased angiogenesis, Irak1 and Bicd2 expression, and p38 phosphorylation in human skin organoids as a model of tissue injury. Collectively, targeting miR-4674 may provide a novel therapeutic target for tissue repair in pathological disease states associated with impaired angiogenesis.

Angioregulatory microRNAs in Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of cancer mortality. Angiogenesis is a rate-determining step in CRC development and metastasis. The balance of angiogenic and antiangiogenic factors is crucial in this process. Angiogenesis-related genes can be regulated post-transcriptionally by microRNAs (miRNAs) and some miRNAs have been shown to shuttle between tumor cells and the tumor microenvironment (TME). MiRNAs have context-dependent actions and can promote or suppress angiogenesis dependent on the type of cancer. On the one hand, miRNAs downregulate anti-angiogenic targets and lead to angiogenesis induction. Tumor suppressor miRNAs, on the other hand, enhance anti-angiogenic response by targeting pro-angiogenic factors. Understanding the interaction between these miRNAs and their target mRNAs will help to unravel molecular mechanisms involved in CRC progression. The aim of this article is to review the current literature on angioregulatory miRNAs in CRC.

Exosomes derived from human CD34+ stem cells transfected with miR-26a prevent glucocorticoid-induced osteonecrosis of the femoral head by promoting angiogenesis and osteogenesis

Background

Damaged endothelial cells and downregulated osteogenic ability are two key pathogenic mechanisms of glucocorticoid (GC)-induced osteonecrosis of the femoral head (ONFH). Recent studies suggested that transplantation of CD34⁺ stem cell-derived exosomes (CD34⁺-Exos) can treat ischemic diseases by promoting neovascularization and that miR-26a is an important positive regulator of osteogenesis. Moreover, the biological effect of exosomes is closely related to their cargo miRNAs. However, it is not clear whether increasing the abundance of miR-26a in CD34⁺-Exos will inhibit the progress of GC-induced ONFH.

Methods

MiR-26a was overexpressed in CD34⁺-Exos (miR-26a-CD34⁺-Exos) to increase their osteogenic potential. The angiogenic potential of miR-26a-CD34⁺-Exos was then examined through evaluations of migration and tube-forming capacities in vitro. In addition, in order to observe the osteogenic effect of miR-26a-CD34⁺-Exos on bone marrow stromal cells (BMSCs), Alizarin red staining, alkaline phosphatase (ALP) activity assays, and qPCR were carried out. Finally, miR-26a-CD34⁺-Exos were injected into a GC-induced ONFH rat model to prevent the progress of GC-induced ONFH. The biological effects of miR-26a-CD34⁺-Exos on the ONFH model were evaluated by micro-CT, angiography, and histological staining.

Results

Our data showed that miR-26a-CD34⁺-Exos enhanced human umbilical vein endothelial cell migration and tube-forming capacities. Furthermore, miR-26a-CD34⁺-Exos strengthened the osteogenic differentiation of BMSCs under the influence of GCs in vitro. Finally, the miR-26a-CD34⁺-Exos increased the vessel density and trabecular bone integrity of the femoral head in the GC-induced ONFH rat model, which inhibited the progress of ONFH.

Conclusions

MiR-26a-CD34⁺-Exos protect the femoral head from damage caused by GCs by strengthening angiogenesis and osteogenesis. The biological effect of miR-26a-CD34⁺-Exos make them suitable for application in the prevention of GC-induced ONFH.

The role of epigenetic changes in preeclampsia

Preeclampsia (PE) is a disorder affecting 2-10% of pregnancies and has a major role for perinatal and maternal mortality and morbidity. PE can be occurred by initiation of new hypertension combined with proteinuria after 20 weeks gestation, as well as various reasons such as inflammatory cytokines, poor trophoblast invasion can be related with PE disease. Environmental factors can cause epigenetic changes including DNA methylation, microRNAs (miRNAs), and histone modification that may be related to different diseases such as PE. Abnormal DNA methylation during placentation is the most important epigenetic factor correlated with PE. Moreover, changes in histone modification like acetylation and also the effect of overregulation or low regulation of miRNAs or long noncoding RNAs on variety signaling pathways can be resulted in PE. The aim of this review is to describe of studies about epigenetic changes in PE and its therapeutic strategies.

MicroRNA-615-5p Regulates Angiogenesis and Tissue Repair by Targeting AKT/eNOS (Protein Kinase B/Endothelial Nitric Oxide Synthase) Signaling in Endothelial Cells

Objective- In response to tissue injury, the appropriate progression of events in angiogenesis is controlled by a careful balance between pro and antiangiogenic factors. We aimed to identify and characterize microRNAs that regulate angiogenesis in response to tissue injury. Approach and Results- We show that in response to tissue injury, microRNA-615-5p (miR-615-5p) is rapidly induced and serves as an antiangiogenic microRNA by targeting endothelial cell VEGF (vascular endothelial growth factor)-AKT (protein kinase B)/eNOS (endothelial nitric oxide synthase) signaling in vitro and in vivo. MiR-615-5p expression is increased in wounds of diabetic db/db mice, in plasma of human subjects with acute coronary syndromes, and in plasma and skin of human subjects with diabetes mellitus. Ectopic expression of miR-615-5p markedly inhibited endothelial cell proliferation, migration, network tube formation in Matrigel, and the release of nitric oxide, whereas miR-615-5p neutralization had the opposite effects. Mechanistic studies using transcriptomic profiling, bioinformatics, 3' untranslated region reporter and microribonucleoprotein immunoprecipitation assays, and small interfering RNA dependency studies demonstrate that miR-615-5p inhibits the VEGF-AKT/eNOS signaling pathway in endothelial cells by targeting IGF2 (insulin-like growth factor 2) and RASSF2 (Ras-associating domain family member 2). Local delivery of miR-615-5p inhibitors, markedly increased angiogenesis, granulation tissue thickness, and wound closure rates in db/db mice, whereas miR-615-5p mimics impaired these effects. Systemic miR-615-5p neutralization improved skeletal muscle perfusion and angiogenesis after hindlimb ischemia in db/db mice. Finally, modulation of miR-615-5p expression dynamically regulated VEGF-induced AKT signaling and angiogenesis in human skin organoids as a model of tissue injury. Conclusions- These findings establish miR-615-5p as an inhibitor of VEGF-AKT/eNOS-mediated endothelial cell angiogenic responses and that manipulating miR-615-5p expression could provide a new target for angiogenic therapy in response to tissue injury. Visual Overview- An online visual overview is available for this article.