Overexpression of miR-29b reduces collagen biosynthesis by inhibiting heat shock protein 47 during skin wound healing

Downregulation of microRNA-29b in cancer and fibrosis: molecular insights and clinical implications

MicroRNA-29b (miR-29b) is known for its therapeutic potential as an antifibrotic and anticancer agent. In fibrotic conditions, miR-29b inhibits fibrogenesis by downregulating crucial regulators such as collagens, extracellular matrix proteins and the transforming growth factor-β pathway. Similarly, in cancer, it acts as a tumor suppressor by downregulating various oncogenes and signaling pathways involved in cancer progression, such as Wnt-β-catenin, p38-mitogen-activated protein kinase and nuclear factor-κB. However, the upregulation of these pathways suppresses miR-29b, contributing to fibrosis and cancer development. Preclinical research and clinical trials have shown that delivering exogenous miR-29b mimics can restore its expression, attenuating tumorigenesis and fibrogenesis. This review discusses miR-29b's potential and its possible therapeutic development for cancer and fibrotic disorders.

Release of miR-29 Target Laminin C2 Improves Skin Repair

miRNAs are small noncoding RNAs that regulate mRNA targets in a cell-specific manner. miR-29 is expressed in murine and human skin, where it may regulate functions in skin repair. Cutaneous wound healing model in miR-29a/b1 gene knockout mice was used to identify miR-29 targets in the wound matrix, where angiogenesis and maturation of provisional granulation tissue was enhanced in response to genetic deletion of miR-29. Consistently, antisense-mediated inhibition of miR-29 promoted angiogenesis in vitro by autocrine and paracrine mechanisms. These processes are likely mediated by miR-29 target mRNAs released upon removal of miR-29 to improve cell-matrix adhesion. One of these, laminin (Lam)-c2 (also known as laminin γ2), was strongly up-regulated during skin repair in the wound matrix of knockout mice. Unexpectedly, Lamc2 was deposited in the basal membrane of endothelial cells in blood vessels forming in the granulation tissue of knockout mice. New blood vessels showed punctate interactions between Lamc2 and integrin α6 (Itga6) along the length of the proto-vessels, suggesting that greater levels of Lamc2 may contribute to the adhesion of endothelial cells, thus assisting angiogenesis within the wound. These findings may be of translational relevance, as LAMC2 was deposited at the leading edge in human wounds, where it formed a basal membrane for endothelial cells and assisted neovascularization. These results suggest a link between LAMC2, improved angiogenesis, and re-epithelialization.

Recent applications of RNA therapeutic in clinics

Ribonucleic acid (RNA) therapy has been extensively researched for several decades and has garnered significant attention in recent years owing to its potential in treating a broad spectrum of diseases. It falls under the domain of gene therapy, leveraging RNA molecules as a therapeutic approach in medicine. RNA can be targeted using small-molecule drugs, or RNA molecules themselves can serve as drugs by interacting with proteins or other RNA molecules. While several RNA drugs have been granted clinical approval, numerous RNA-based therapeutics are presently undergoing clinical investigation or testing for various conditions, including genetic disorders, viral infections, and diverse forms of cancer. These therapies offer several advantages, such as high specificity, enabling precise targeting of disease-related genes or proteins, cost-effectiveness, and a relatively straightforward manufacturing process. Nevertheless, successful translation of RNA therapies into widespread clinical use necessitates addressing challenges related to delivery, stability, and potential off-target effects. This chapter provides a comprehensive overview of the general concepts of various classes of RNA-based therapeutics, the mechanistic basis of their function, as well as recent applications of RNA therapeutic in clinics.

Potential roles of circulating microRNAs in the healing of type 1 diabetic wounds treated with green tea extract: molecular and biochemical study

Background

Circulating miRNAs have been implicated in various aspects of diabetic wound healing, including inflammation, angiogenesis, and extracellular matrix remodeling. Thus, in alternative herbal medicine strategies, miRNAs will be potential therapeutic molecular targets in nonhealing wounds. These could be valuable elements for understanding the molecular basis of diabetic wound healing and could be used as good elements in bioinformatics.

Objectives

To elucidate the molecular mechanisms of microRNAs in association with apoptosis-inducing genes in controlling skin wound healing in diabetic wounds treated with green tea polyphenols (GTPs).

Methods

Green tea hydro extract (GTE) at doses of100-200 mg/ml was topically applied to the skin tissues of rats with T1DM induced by a single dose of streptozotocin (STZ; 100 mg/kg, in 0.01 M sodium citrate, pH 4.3-4.5) injected intraperitoneally for seven consecutive days to induce T1DM. The rats were treated with green tea for three weeks. A sterile surgical blade was used to inflict a circular wound approximately 2 cm in diameter on the anterior-dorsal side of previously anesthetized rats by a combination of ketamine hydrochloride (50 mg/kg, i.e., body weight) and xylazine hydrochloride. Afterward, the molecular roles of the circulating miRNAs miR-21, miR-23a, miR-146a, and miR-29b and apoptotic genes were determined by quantitative real-time PCR to evaluate Bax, Caspase-3, and Bcl-2 in wound healing. In addition, HPLC analysis was also performed to estimate the active polyphenols (GTPs) present in the hydro extract of green tea leaves.

Results

Wound healing was improved in diabetic skin wounds following treatment with GTE at doses of 100-200 mg/dl for three weeks. The wound parameters contraction, epithelialization, and scar formation significantly improved in a short time (14 days) compared to the longer periods identified in diabetic non-treated rats (20 days) and the standard control (15.5 days). Molecular analyses reported a significant increase in the levels of miR-21, miR-23a, and miR-146a and a decrease in the levels of miR-29b in green tea-treated diabetic rats compared to those in the standard control and STZ-diabetic non-treated rats. In addition, the molecular apoptotic genes Bax and caspase-3 significantly increased, and the BcL-2 gene significantly decreased following treatment with green tea polyphenols.

Conclusions

The data showed that active green tea polyphenols (GTPs) present in GTE significantly improved diabetic wound healing by controlling apoptotic genes and the circulating microRNAs miR-21, miR-23a, miR-146a, and miR-29b, which might be involved in cellular apoptosis and angiogenesis processes. Thus, to establish a future model for the treatment of diabetic wounds, further studies are needed to understand the potential association of these biological parameters with the wound-healing process in diabetic wounds.

Bone marrow mesenchymal stem cell-derived exosome miR-29b-3p alleviates UV irradiation-induced photoaging in skin fibroblast

BACKGROUND

Mesenchymal stem cells-derived exosome (MSCs-exo) was identified to reduce photoaging. The purpose of this study was to investigate the potential role of microRNA (miR)-29b-3p derived from bone marrow MSCs-exo (BMSCs-exo) in photoaging.

METHODS

Exosomes were isolated from BMSCs and verified by Western blot. A photoaging cell model was constructed by UVB irradiation of human dermal fibroblasts (HDFs). Quantitative real-time PCR (RT-qPCR) was performed to detect the mRNA levels of miR-29b-3p, collagen type I and matrix metalloproteinases (MMPs). CCK-8, Transwell and flow cytometry were applicated to examine cell viability, migration and apoptosis. Commercial kits are used to measure levels of oxidative stress indicators. Finally, a dual-luciferase reporter assay was applied to validate the target of miR-29b-3p.

RESULTS

Extracted exosomes were positive for HSP70 and CD9. Survival of HDFs increased in an exosome concentration-dependent manner. UVB irradiation inhibited miR-29b-3p levels compared with controls, but BMSCs-exo treatment restored miR-29b-3p levels (p < .05). Additionally, BMSCs-exo-miR-29b-3p reversed the inhibition of HDFs migration and oxidative stress by UVB irradiation, as well as the promotion of apoptosis. However, this reversal was attenuated by the suppression of miR-29b-3p (p < .05). Furthermore, BMSCs-exo-miR-29b-3p also inhibited the degradation of collagen type I and the production of MMPs in photoaging, and they were also eliminated by the reduced miR-29b-3p. Finally, MMP-2 was the target gene of miR-29b-3p.

CONCLUSION

Our study presented a novel role for BMSCs-exo-miR-29b-3p in improving skin photoaging function, and these findings may provide new insights into the targeted treatment of skin photoaging.

Innovative Treatment Strategies to Accelerate Wound Healing: Trajectory and Recent Advancements

Wound healing is highly specialized dynamic multiple phase process for the repair of damaged/injured tissues through an intricate mechanism. Any failure in the normal wound healing process results in abnormal scar formation, and chronic state which is more susceptible to infections. Chronic wounds affect patients’ quality of life along with increased morbidity and mortality and are huge financial burden to healthcare systems worldwide, and thus requires specialized biomedical intensive treatment for its management. The clinical assessment and management of chronic wounds remains challenging despite the development of various therapeutic regimens owing to its painstakingly long-term treatment requirement and complex wound healing mechanism. Various conventional approaches such as cell therapy, gene therapy, growth factor delivery, wound dressings, and skin grafts etc., are being utilized for promoting wound healing in different types of wounds. However, all these abovementioned therapies are not satisfactory for all wound types, therefore, there is an urgent demand for the development of competitive therapies. Therefore, there is a pertinent requirement to develop newer and innovative treatment modalities for multipart therapeutic regimens for chronic wounds. Recent developments in advanced wound care technology includes nanotherapeutics, stem cells therapy, bioengineered skin grafts, and 3D bioprinting-based strategies for improving therapeutic outcomes with a focus on skin regeneration with minimal side effects. The main objective of this review is to provide an updated overview of progress in therapeutic options in chronic wounds healing and management over the years using next generation innovative approaches. Herein, we have discussed the skin function and anatomy, wounds and wound healing processes, followed by conventional treatment modalities for wound healing and skin regeneration. Furthermore, various emerging and innovative strategies for promoting quality wound healing such as nanotherapeutics, stem cells therapy, 3D bioprinted skin, extracellular matrix-based approaches, platelet-rich plasma-based approaches, and cold plasma treatment therapy have been discussed with their benefits and shortcomings. Finally, challenges of these innovative strategies are reviewed with a note on future prospects.

Inflammation, oxidative stress and altered heat shock response in type 2 diabetes: the basis for new pharmacological and non-pharmacological interventions

Type 2 diabetes mellitus (DM2) is a chronic disease characterised by variable degrees of insulin resistance and impaired insulin secretion. Besides, several pieces of evidence have shown that chronic inflammation, oxidative stress, and 70 kDa heat shock proteins (HSP70) are strongly involved in DM2 and its complications, and various pharmacological and non-pharmacological treatment alternatives act in these processes/molecules to modulate them and ameliorate the disease. Besides, uncontrolled hyperglycaemia is related to several complications as diabetic retinopathy, neuropathy and hepatic, renal and cardiac complications. In this review, we address discuss the involvement of different inflammatory and pro-oxidant pathways related to DM2, and we described molecular targets modulated by therapeutics currently available to treat DM2.

Current Advances in RNA Therapeutics for Human Diseases

Following the discovery of nucleic acids by Friedrich Miescher in 1868, DNA and RNA were recognized as the genetic code containing the necessary information for proper cell functioning. In the years following these discoveries, vast knowledge of the seemingly endless roles of RNA have become better understood. Additionally, many new types of RNAs were discovered that seemed to have no coding properties (non-coding RNAs), such as microRNAs (miRNAs). The discovery of these new RNAs created a new avenue for treating various human diseases. However, RNA is relatively unstable and is degraded fairly rapidly once administered; this has led to the development of novel delivery mechanisms, such as nanoparticles to increase stability as well as to prevent off-target effects of these molecules. Current advances in RNA-based therapies have substantial promise in treating and preventing many human diseases and disorders through fixing the pathology instead of merely treating the symptomology similarly to traditional therapeutics. Although many RNA therapeutics have made it to clinical trials, only a few have been FDA approved thus far. Additionally, the results of clinical trials for RNA therapeutics have been ambivalent to date, with some studies demonstrating potent efficacy, whereas others have limited effectiveness and/or toxicity. Momentum is building in the clinic for RNA therapeutics; future clinical care of human diseases will likely comprise promising RNA therapeutics. This review focuses on the current advances of RNA therapeutics and addresses current challenges with their development.

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.

The Regulation of Collagen Processing by miRNAs in Disease and Possible Implications for Bone Turnover

This article describes several recent examples of miRNA governing the regulation of the gene expression involved in bone matrix construction. We present the impact of miRNA on the subsequent steps in the formation of collagen type I. Collagen type I is a main factor of mechanical bone stiffness because it constitutes 90-95% of the organic components of the bone. Therefore, the precise epigenetic regulation of collagen formation may have a significant influence on bone structure. We also describe miRNA involvement in the expression of genes, the protein products of which participate in collagen maturation in various tissues and cancer cells. We show how non-collagenous proteins in the extracellular matrix are epigenetically regulated by miRNA in bone and other tissues. We also delineate collagen mineralisation in bones by factors that depend on miRNA molecules. This review reveals the tissue variability of miRNA regulation at different levels of collagen maturation and mineralisation. The functionality of collagen mRNA regulation by miRNA, as proven in other tissues, has not yet been shown in osteoblasts. Several collagen-regulating miRNAs are co-expressed with collagen in bone. We suggest that collagen mRNA regulation by miRNA could also be potentially important in bone metabolism.

miR-24-3p obstructs the proliferation and migration of HSFs after thermal injury by targeting PPAR-β and positively regulated by NF-κB

Thermal injury repair is a complex process during which the maintenance of the proliferation and migration of human skin fibroblasts (HSFs) exert a crucial role. MicroRNAs have been proven to exert an essential function in repairing skin burns. This study delves into the regulatory effects of miR-24-3p on the migration and proliferation of HSFs that have sustained a thermal injury; thereby, providing deeper insight into thermal injury repair pathogenesis. The PPAR-β protein expression level progressively increased in a time-dependent manner on the 12^th , 24^th , and 48^th hour following the thermal injury of the HSFs. The knockdown of PPAR-β markedly suppressed the proliferation of and migration of HSF. Following thermal injury, the knockdown also promoted the inflammatory cytokine IL-6, TNF-, PTGS-2, and P65 expression. PPAR-β contrastingly exhibited an opposite trend. A targeted relationship between PPAR-β and miR-24-3p was predicted and verified. miR-24-3p inhibited thermal injured-HSFs proliferation and migration and facilitated inflammatory cytokine expression through the regulation of PPAR-β. p65 directly targeted the transcriptional precursor of miR-24 and promoted miR-24 expression. A negative correlation between miR-24-3p expression level and PPAR-β expression level in rats burnt dermal tissues was observed. Our findings reveal that miR-24-3p is conducive to rehabilitating the denatured dermis, which may be beneficial in providing effective therapy of skin burns.

miR-29b Regulates TGF-β1-Induced Epithelial-Mesenchymal Transition by Inhibiting Heat Shock Protein 47 Expression in Airway Epithelial Cells

Tissue remodeling contributes to ongoing inflammation and refractoriness of chronic rhinosinusitis (CRS). During this process, epithelial-mesenchymal transition (EMT) plays an important role in dysregulated remodeling and both microRNA (miR)-29b and heat shock protein 47 (HSP47) may be engaged in the pathophysiology of CRS. This study aimed to determine the role of miR-29b and HSP47 in modulating transforming growth factor (TGF)-β1-induced EMT and migration in airway epithelial cells. Expression levels of miR-29b, HSP47, E-cadherin, α-smooth muscle actin (α-SMA), vimentin and fibronectin were assessed through real-time PCR, Western blotting, and immunofluorescence staining. Small interfering RNA (siRNA) targeted against miR-29b and HSP47 were transfected to regulate the expression of EMT-related markers. Cell migration was evaluated with wound scratch and transwell migration assay. miR-29b mimic significantly inhibited the expression of HSP47 and TGF-β1-induced EMT-related markers in A549 cells. However, the miR-29b inhibitor more greatly induced the expression of them. HSP47 knockout suppressed TGF-β1-induced EMT marker levels. Functional studies indicated that TGF-β1-induced EMT was regulated by miR-29b and HSP47 in A549 cells. These findings were further verified in primary nasal epithelial cells. miR-29b modulated TGF-β1-induced EMT-related markers and migration via HSP47 expression modulation in A549 and primary nasal epithelial cells. These results suggested the importance of miR-29b and HSP47 in pathologic tissue remodeling progression in CRS.

Exosomes from miR-29a-modified adipose-derived mesenchymal stem cells reduce excessive scar formation by inhibiting TGF-β2/Smad3 signaling

Pathological scars mainly refer to hypertrophic scars and keloids, and have a high incidence. Moreover, these scars seriously affect the patient's appearance and are associated with significant pain. The present study aimed to investigate the inhibitory effect of microRNA (miR)-29a from human adipose-derived mesenchymal stem cells (hADSCs) exosomes on scar formation. Firstly, the expression of miR-29a in thermal skin tissues of mice and human hypertrophic scar fibroblasts (HSFBs) was detected via reverse transcription-quantitative PCR. Exosomes derived from miR-29a-modified hADSCs were extracted and the influence of miR-29a-modified hADSCs-exo on the proliferation and function of HSFBs was determined. Lastly, the effect of miR-29a-modified hADSCs-exo on scar formation was determined using a thermal mouse model. The results demonstrated that miR-29a was downregulated in scar tissues after scalding and in HSFBs. After treating HSFBs with miR-29a-modified hADSC exosomes, miR-29a-overexpressing hADSC exosomes inhibited the proliferation and migration of HSFBs. Moreover, it was found that TGF-β2 was the target of miR-29a, and that hADSC exosome-derived miR-29a inhibited the fibrosis of HSFBs and scar hyperplasia after scalding in mice by targeting the TGF-β2/Smad3 signaling pathway. In summary, the current data indicated that miR-29a-modified hADSC exosome therapy can decrease scar formation by inhibiting the TGF-β2/Smad3 signaling pathway via its derived exogenous miR-29a, and this may be useful for the future treatment of pathological scars by providing a potential molecular basis.

Adipose-derived stem cell induced-tissue repair or wound healing is mediated by the concomitant upregulation of miR-21 and miR-29b expression and activation of the AKT signaling pathway

BACKGROUND

Adipose-derived stem cells (ADSCs), a subpopulation of mesenchymal stem cells, are characterized by their potential to differentiate into multiple cell lineages. Due to their abundance and relative ease of procurement, ADSCs are widely used for tissue repair and regeneration. However, the molecular mechanisms of the therapeutic effect of ADSCs remain unknown.

METHODS

MicroRNAs have emerged as important signaling molecules in skin wound healing, and their roles in ADSC-based therapies must be addressed. Here, we investigated the potential of ADSCs in improving cutaneous wound healing in vitro and in vivo.

RESULTS

We simulated the microenvironment of the wound site by coculturing human dermal fibroblasts (HDFs) with ADSCs. We found that cocultured HDFs expressed significantly higher levels of miR-29b and miR-21 and had higher proliferation and migration rates than ADSCs cultured without HDFs. Moreover, increased expression of Collagen Type I Alpha 1 Chain (COL1A1), Collagen Type III Alpha 1 Chain (COL3A1), alpha-smooth muscle actin (α-SMA), vascular endothelial growth factor (VEGF), and Phosphoinositide 3-kinase (PI3K), p-Akt and decreased expression of Phosphatase and tensin homolog (PTEN) and matrix metalloproteinase (MMP)-1 was detected, suggesting extracellular remodeling and fibroblast activation and proliferation. We validated the in vitro results by using a rodent skin excisional wound model and implanted ADSC sheets in the wound. Compared with the controls, wounds implanted with ADSC sheets had significantly higher rates of wound-closure; increased expression of α-SMA, VEGF, PI3k, PTEN, COL1A1, and COL3A1; decreased expression of PTEN and MMP1; and upregulated levels of miR-29b and miR-21 in the skin.

CONCLUSION

In summary, we evidenced that ADSCs facilitate the increase in miR-29b and miR-21 levels and promote the activation and proliferation of dermal fibroblasts and extracellular matrix (ECM) remodeling, with the associated release of VEGF. Thus, the ADSC-mediated increase in microRNAs is essential in tissue repair and has a therapeutic potential in cutaneous wound healing.

The Role of miRNAs in Extracellular Matrix Repair and Chronic Fibrotic Lung Diseases

The lung extracellular matrix (ECM) plays a key role in the normal architecture of the lung, from embryonic lung development to mechanical stability and elastic recoil of the breathing adult lung. The lung ECM can modulate the biophysical environment of cells through ECM stiffness, porosity, topography and insolubility. In a reciprocal interaction, lung ECM dynamics result from the synthesis, degradation and organization of ECM components by the surrounding structural and immune cells. Repeated lung injury and repair can trigger a vicious cycle of aberrant ECM protein deposition, accompanied by elevated ECM stiffness, which has a lasting effect on cell and tissue function. The processes governing the resolution of injury repair are regulated by several pathways; however, in chronic lung diseases such as asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary disease (IPF) these processes are compromised, resulting in impaired cell function and ECM remodeling. Current estimates show that more than 60% of the human coding transcripts are regulated by miRNAs. miRNAs are small non-coding RNAs that regulate gene expressions and modulate cellular functions. This review is focused on the current knowledge of miRNAs in regulating ECM synthesis, degradation and topography by cells and their dysregulation in asthma, COPD and IPF.

Sequential Release of Small Extracellular Vesicles from Bilayered Thiolated Alginate/Polyethylene Glycol Diacrylate Hydrogels for Scarless Wound Healing

Excessive scar formation has adverse physiological and psychological effects on patients; therefore, a therapeutic strategy for rapid wound healing and reduced scar formation is urgently needed. Herein, bilayered thiolated alginate/PEG diacrylate (BSSPD) hydrogels were fabricated for sequential release of small extracellular vesicles (sEVs), which acted in different wound healing phases, to achieve rapid and scarless wound healing. The sEVs secreted by bone marrow derived mesenchymal stem cells (B-sEVs) were released from the lower layer of the hydrogels to promote angiogenesis and collagen deposition by accelerating fibroblast and endothelial cell proliferation and migration during the early inflammation and proliferation phases, while sEVs secreted by miR-29b-3p-enriched bone marrow derived mesenchymal stem cells were released from the upper layer of the hydrogels and suppressed excessive capillary proliferation and collagen deposition during the late proliferation and maturation phases. In a full-thickness skin defect model of rats and rabbit ears, the wound repair rate, angiogenesis, and collagen deposition were evaluated at different time points after treatment with BSSPD loaded with B-sEVs. Interestingly, during the end of the maturation phase in the in vivo model, tissues in the groups treated with BSSPD loaded with sEVs for sequential release (SR-sEVs@BSSPD) exhibited a more uniform vascular structure distribution, more regular collagen arrangement, and lower volume of hyperplastic scar tissue than tissues in the other groups. Hence, SR-sEVs@BSSPD based on skin repair phases was successfully designed and has considerable potential as a cell-free therapy for scarless wound healing.

Functional Dissection of CD26 and Its Pharmacological Inhibition by Sitagliptin During Skin Wound Healing

BACKGROUND Skin fibroblasts are primary mediators underlying wound healing and therapeutic targets in scar prevention and treatment. CD26 is a molecular marker to distinguish fibroblast subpopulations and plays an important role in modulating the biological behaviors of dermal fibroblasts and influencing skin wound repair. Therapeutic targeting of specific fibroblast subsets is expected to reduce skin scar formation more efficiently. MATERIAL AND METHODS Skin burn and excisional wound healing models were surgically established in mice. The expression patterns of CD26 during wound healing were determined by immunohistochemical staining, real-time RT-PCR, and western blot assays. Normal fibroblasts from intact skin (NFs) and fibroblasts in wounds (WFs) were isolated and sorted by fluorescence-activated cell sorting (FACS) into 4 subgroups - CD26⁺ NFs, CD26⁻ NFs, CD26⁺ WFs, and CD26⁻ WFs - for comparisons of their capacities of proliferation, migration, and collagen synthesis. Pharmacological inhibition of CD26 by sitagliptin in skin fibroblasts and during wound healing were further assessed both in vitro and in vivo. RESULTS Increased CD26 expression was observed during skin wound healing in both models. The CD26⁺ fibroblasts isolated from wounds had significantly stronger abilities to proliferate, migrate, and synthesize collagen than other fibroblast subsets. Sitagliptin treatment potently diminished CD26 expression, impaired the proliferation, migration, and collagen synthesis of fibroblasts in vitro, and diminished scar formation in vivo. CONCLUSIONS Our data reveal that CD26 is functionally involved in skin wound healing by regulating cell proliferation, migration, and collagen synthesis in fibroblasts. Pharmacological inhibition of CD26 by sitagliptin might be a viable strategy to reduce skin scar formation.

SERPINH1, Targeted by miR-29b, Modulated Proliferation and Migration of Human Retinal Endothelial Cells Under High Glucose Conditions

AIM

In the present study, we performed bioinformatics studies and in vitro functional assays to explore the underlying role of serpin family H member 1 (SERPINH1) in the diabetic retinopathy.

METHODS

Common differentially expressed genes (DEGs) between diabetic retinal tissues and normal retinal tissues were analyzed using Gene Expression Omnibus (GEO) database. The proliferation and migration of human retinal endothelial cells (HRECs) was evaluated by MTS, EdU and wound healing assays, respectively; the miRNA and mRNAs expression levels of hub genes in HRECs were determined using quantitative real-time PCR (qRT-PCR). Protein levels were determined using a Western blot assay.

RESULTS

A total of 189 common DEGs were screened between two GEO datasets (GSE60436 and GSE94019), and ten potential hub genes that may link to the progression of diabetic retinopathy were detected. The qRT-PCR results showed that collagen, type I, alpha 1 (COL1A1), Collagen, type I, alpha 2 (COL1A2) and serpin family H member 1 (SERPINH1) mRNA expression levels were up-regulated in the HRECs after being exposed to high glucose for 48 h. Silence of SERPINH1 repressed the high glucose-induced increase in proliferation and migration of HRECs. SERPINH1 was a target of miR-29b and was suppressed by miR-29 in HRECs. SERPINH1 overexpression promoted HREC proliferation and migration. Furthermore, miR-29b suppressed HREC proliferation and migration under high-glucose stimulation, which was significantly attenuated by enforced expression of SERPINH1.

CONCLUSION

In conclusion, by performing the integrated bioinformatics analysis, the present study suggested that 3 hub genes (COL1A1, COL1A2 and SERPINH1) may be associated with diabetic retinopathy pathophysiology. Further mechanistic studies indicated that miR-29b/SERPINH1 signaling participated in high glucose-induced enhancement in the proliferation and migration of HRECs.

Evidence of stage progression in a novel, validated fluorescence-navigated and microsurgical-assisted secondary lymphedema rodent model

Secondary lymphedema (SL)is a frequent and devastating complication of modern oncological therapy and filarial infections. A lack of a reliable preclinical model to investigate the underlying mechanism of clinical stage progression has limited the development of new therapeutic strategies. Current first line treatment has shown to be merely symptomatic and relies on lifetime use of compression garments and decongestive physiotherapy. In this study, we present the development of a secondary lymphedema model in 35 rats using pre- and intraoperative fluorescence-guided mapping of the lymphatics and microsurgical induction. In contrast to the few models reported so far, we decided to avoid the use of radiation for lymphedema induction. It turned out, that the model is nearly free of complications and capable of generating a statistically significant limb volume increase by water displacement measurements, sustained for at least 48 days. A translational, accurate lymphatic dysfunction was visualized by a novel VIS-NIR X-ray ICG-Clearance-Capacity imaging technology. For the first-time SL stage progression was validated by characteristic histological alterations, such as subdermal mast cell infiltration, adipose tissue deposition, and fibrosis by increased skin collagen content. Immunofluorescence confocal microscopy analysis suggested that stage progression is related to the presence of a characteristic α SMA+/HSP-47+/vimentin+ fibroblast subpopulation phenotype. These findings demonstrate that the in-vivo model is a reliable and clinically relevant SL model for the development of further secondary lymphedema therapeutic strategies and the analysis of the veiled molecular mechanisms of lymphatic dysfunction.

Liraglutide-loaded PLGA/gelatin electrospun nanofibrous mats promote angiogenesis to accelerate diabetic wound healing via the modulation of miR-29b-3p

Diabetic wounds remain a serious clinical challenge whereas current therapies have limited effects on reducing the high disability and morbidity. Impaired vascularization is closely associated with delayed healing of diabetic wounds and liraglutide (Lira), a GLP-1R receptor agonist, has been reported to promote the angiogenic ability of endothelial cells. However, its application is hindered owing to the unsustainable drug concentration. In this study, we prepared a poly (lactic-co-glycolic acid)/gelatin (PLGA/Gel) nanofibrous mat scaffold to sustain the release of Lira for skin tissue engineering through 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide/N-hydroxy sulfosuccinimide (EDC/NHS), a green cross-linking-graft integration method. The incorporation of Lira into PLGA/Gel increased the pore size, hydrophilicity, elasticity and degradation properties of nanofibrous mats, which were advantageous to wound healing. In addition, the effects on diabetic wound healing, vascularization and its underlying mechanism were evaluated. The results revealed that PLGA/Gel/Lira remarkably improved the healing efficiency of diabetic dermal wounds characterized by shortened wound closure time, increased blood vessel density, and elevated collagen deposition and alignment. In vitro, Lira reversed the inhibitory effects on proliferation, migration, tube differentiation, and VEGF secretion of endothelial cells induced by high glucose (HG). As for the underlying mechanism, Lira specifically decreased the level of miR-29b-3p, targeting the AKT/GSK-3β/β-catenin pathway to regulate the biological function of endothelial cells. In conclusion, for the first time this study combined PLGA/Gel with Lira to take advantage of their synergistic effects to promote vascularization, a promising strategy to accelerate diabetic wound repair.

LncRNA XIST promotes extracellular matrix synthesis, proliferation and migration by targeting miR-29b-3p/COL1A1 in human skin fibroblasts after thermal injury

Background

Long noncoding RNAs (lncRNAs) have been reported to be associated with dermis process during burn wound healing. This study aimed to investigate the role of lncRNA X-inactive specific transcript (XIST) in human skin fibroblasts (HSF) and extracellular matrix (ECM) as well as the regulatory network of XIST/microRNA-29b-3p (miR-29b-3p)/collagen 1 alpha 1 (COL1A1).

Methods

The wound samples were collected from 25 patients with deep partial thickness burn at day 5 after burn. The thermal injured model was established using HSF cells. The expressions of XIST, miR-29b-3p and COL1A1 were measured by quantitative real-time polymerase chain reaction and western blot. ECM synthesis, cell proliferation and migration were detected by western blot, cell counting kit-8 and trans-well assays, respectively. The interaction between miR-29b-3p and XIST or COL1A1 was explored by bioinformatics analysis and luciferase reporter assay.

Results

The expressions of XIST and COL1A1 were enhanced but miR-29b-3p expression was decreased after thermal injury. XIST overexpression promoted ECM synthesis, cell proliferation and migration in thermal injured HSF cells. However, XIST knockdown played an opposite effect. miR-29b-3p overexpression inhibited ECM synthesis, cell proliferation and migration, which was reversed by XIST. COL1A1 silence suppressed ECM synthesis, cell proliferation and migration by miR-29b-3p targeting. Moreover, COL1A1 up-regulation weakened the effect of XIST silence on ECM synthesis and HSF cell function.

Conclusion

XIST promoted ECM synthesis, cell proliferation and migration by sponging miR-29b-3p and targeting COL1A1 in HSF cells after thermal injury, indicating the promoting role of XIST in wound healing.

Therapeutic strategies for enhancing angiogenesis in wound healing

The enhancement of wound healing has been a goal of medical practitioners for thousands of years. The development of chronic, non-healing wounds is a persistent medical problem that drives patient morbidity and increases healthcare costs. A key aspect of many non-healing wounds is the reduced presence of vessel growth through the process of angiogenesis. This review surveys the creation of new treatments for healing cutaneous wounds through therapeutic angiogenesis. In particular, we discuss the challenges and advancement that have been made in delivering biologic, pharmaceutical and cell-based therapies as enhancers of wound vascularity and healing.

Baicalein retards proliferation and collagen deposition by activating p38MAPK-JNK via microRNA-29

Immoderate proliferation and deposition of collagen generally result in hypertrophic scars and even keloids. microRNA-29 (miR-29) has been proved as a crucial regulator in these pathological processes. Although mounting evidence have proved baicalein (BAI) impairs scar formation, it is still incompletely understood whether miR-29 participated in the underlying mechanism. In the present study, NIH-3T3 cells were stimulated with BAI, and then cell viability was analyzed by cell counting kit-8 (CCK-8) and Western blot. We further analyzed total soluble collagen, collagen 1, and alpha-smooth muscle actin (α-SMA) in NIH-3T3 cells, which were exposed to transforming growth factor beta 1 (TGF-β1)/BAI, using a Sircol assay kit, quantitative reverse transcription-PCR (qRT-PCR) and Western blot, respectively. Besides, the miR-29 inhibitor was transduced and its transfection efficiency was verified by qRT-PCR. Finally, the phosphorylated p38 mitogen-activated protein kinase (p38MAPK) and c-Jun N-terminal kinase (JNK) were examined by Western blot. BAI effectively retarded NIH-3T3 proliferation in a dose-dependent manner. Besides, TGF-β1-induced deposition of total soluble collagen and synthesis of collagen 1 and α-SMA were repressed by BAI at mRNA and protein levels. However, miR-29 inhibitor reversed the effects of BAI. Remarkably, BAI promoted phosphorylated expression of p38MAPK and JNK while miR-29 inhibitor reversed its effects on the phosphorylated expression of p38MAPK and JNK. BAI effectively weakened the cell viability and repressed TGF-β1-induced total soluble collagen as well as collagen 1 and α-SMA by upregulating miR-29. Mechanically, BAI activates the p38MAPK/JNK pathway by promoting miR-29.

MicroRNA expression analysis of human skin fibroblasts treated with high-fluence light-emitting diode-red light

Skin fibrosis is a chronic debilitating feature of several skin diseases that lead to characteristic increases in dermal fibroblast proliferation and collagen deposition through upregulation in components of the transforming growth factor beta (TGF-B)/SMAD pathway. In contrast to ultraviolet phototherapy, high-fluence light-emitting diode-generated red light (HF-LED-RL, 633 ± 15 nm) is a safe, economic and non-invasive therapy with in vitro evidence that supports modulation of the key cellular characteristics involved in the pathogenesis of skin fibrosis. Limited data exists pertaining to the effects of HF-LED-RL on human skin fibroblast microRNA (miRNA). Herein, we explored the effects of HF-LED-RL on fibroblast miRNA levels using RNA-seq and miRNA expression analysis. Using RNA-seq analysis we found that HF-LED-RL at 320 and 640 J/cm² increased transcription of key miRNA that are involved in skin fibrosis including miRNA-29, miRNA-196a and Let-7a, and decreased transcription of miRNA-21, miRNA-23b and miRNA-31. These microRNA findings provide insight into the molecular underpinnings of HF-LED-RL and highlight potential therapeutic targets of interest for the treatment of skin fibrosis. Additional research on the specific molecular mechanisms underlying HF-LED-RL effects on fibroblasts may provide further mechanistic insight into this therapy and may reveal additional future therapeutic targets for skin fibrosis.

A MicroRNA-29 Mimic (Remlarsen) Represses Extracellular Matrix Expression and Fibroplasia in the Skin

MicroRNA-29 (miR-29) negatively regulates fibrosis and is downregulated in multiple fibrotic organs and tissues, including in the skin. miR-29 mimics prevent pulmonary fibrosis in mouse models but have not previously been tested in the skin. This study aimed to identify pharmacodynamic biomarkers of miR-29 in mouse skin, to translate those biomarkers across multiple species, and to assess the pharmacodynamic activity of a miR-29b mimic (remlarsen) in a clinical trial. miR-29 biomarkers were selected based on gene function and mRNA expression using quantitative reverse transcriptase polymerase chain reaction. Those biomarkers comprised multiple collagens and other miR-29 direct and indirect targets and were conserved across species; remlarsen regulated their expression in mouse, rat, and rabbit skin wounds and in human skin fibroblasts in culture, while a miR-29 inhibitor reciprocally regulated their expression. Biomarker expression translated to clinical proof-of-mechanism; in a double-blinded, placebo-randomized, within-subject controlled clinical trial of single and multiple ascending doses of remlarsen in normal healthy volunteers, remlarsen repressed collagen expression and the development of fibroplasia in incisional skin wounds. These results suggest that remlarsen may be an effective therapeutic to prevent formation of a fibrotic scar (hypertrophic scar or keloid) or to prevent cutaneous fibrosis, such as scleroderma.

Identification and functional analysis of inflammation-related miRNAs in skin wound repair

Inflammation at a wound site is essential for preventing infection. However, misregulated inflammation leads to pathologies of the healing process, including chronic non-healing wounds and scarring. MicroRNAs (miRNAs) are key regulators of the inflammatory response and tissue repair, acting by translational processing of target mRNAs. In the final step of miRNA processing, Argonaute 2 (Ago2)-bound mature miRNA complexes bind to target mRNAs and inhibit their translation. A variety of wound healing-related miRNAs have been identified and their misregulation likely contributes to wound pathologies, including scarring and chronic healing. Recently, we have developed an Ago2-bound mature miRNA purification system that uses Ago2 antibody to analyze the expression of miRNAs from wound tissues by microarray and next generation sequencing. We have identified several wound inflammation-related miRNAs via Ago2-target immunoprecipitation assays and next generation sequencing of wound tissues from wild-type and PU.1 knockout mice, which exhibit no inflammatory response because of a lack of immune cell lineages. We demonstrated that miR-142, an identified inflammation-related miRNA, is essential role for neutrophilic chemotaxis via inhibition of small GTPase translation; its misregulation leads to susceptibility to infection against Staphylococcus aureus at skin wound sites. In this review, we summarize recent advances of miRNA studies in skin wound healing, introduce our miRNA purification system using an immunoprecipitation assay method, and discuss the function of miR-142 in skin wound healing.

Role of MicroRNA in Proliferation Phase of Wound Healing

Wound healing is a complex biological process that is generally composed of four phases: hemostasis, inflammation, proliferation, and remodeling. The proliferation phase is crucial for effective healing compared to other phases. Many critical events occur during this phase, i.e., migration of fibroblasts, re-epithelialization, angiogenesis and wound contraction. Chronic wounds are common and are considered a major public health problem. Therefore, there is the increasing need to discover new therapeutic strategies. MicroRNA (miRNA) research in the field of wound healing is in its early phase, but the knowledge of the recent discoveries is essential for developing effective therapies for the treatment of chronic wounds. In this review, we focused on recently discovered miRNAs which are involved in the proliferation phase of wound healing in the past few years and their role in wound healing.

Effect of miR-29b on the Proliferation and Apoptosis of Pulmonary Artery Smooth Muscle Cells by Targeting Mcl-1 and CCND2

The proliferation and apoptosis of pulmonary artery smooth muscle cells (PASMCs) are considered to be key steps in the progression of pulmonary arterial hypertension (PAH). MicroRNAs (e.g., miR-29b) have been identified in various diseases to be critical modulators of cell growth and apoptosis by targeting Mcl-1 and CCND2. However, the role of miR-29b in PAH remains unknown. So we try to investigate the effect of miR-29b on Mcl-1 and CCND2 protein in PASMCs, analyze the effect of miR-29b on the proliferation of PASMCs, and explore the significance of miR-29b in the proliferation, apoptosis, and gene therapy of PAH. It was observed that gene chip analysis showed miR-29b expression in pulmonary artery tissue. The expression of miR-29b was significantly reduced in PAH model mice. MiR-29b inhibited the proliferation of PASMCs and promoted the apoptosis of PASMCs. Mechanically, miR-29b could inhibit the expression of Mcl-1 and CCND2 protein and silenced Mcl-1 and CCND2 could abolish the change of proliferation and apoptosis of PASMCs. These results demonstrate that miR-29b suppressed cellular proliferation and promoted apoptosis of PASMCs, possibly through the inhibition of Mcl-1 and CCND2. Therefore, miR-29b may serve as a useful therapeutic tool to treat PAH.

Heat Shock Proteins in Vascular Diabetic Complications: Review and Future Perspective

Heat shock proteins (HSPs) are a large family of proteins highly conserved throughout evolution because of their unique cytoprotective properties. Besides assisting protein refolding and regulating proteostasis under stressful conditions, HSPs also play an important role in protecting cells from oxidative stress, inflammation, and apoptosis. Therefore, HSPs are crucial in counteracting the deleterious effects of hyperglycemia in target organs of diabetes vascular complications. Changes in HSP expression have been demonstrated in diabetic complications and functionally related to hyperglycemia-induced cell injury. Moreover, associations between diabetic complications and altered circulating levels of both HSPs and anti-HSPs have been shown in clinical studies. HSPs thus represent an exciting therapeutic opportunity and might also be valuable as clinical biomarkers. However, this field of research is still in its infancy and further studies in both experimental diabetes and humans are required to gain a full understanding of HSP relevance. In this review, we summarize current knowledge and discuss future perspective.

Regulation function of MMP-1 downregulated by siRNA on migration of heat-denatured dermal fibroblasts

Cutaneous wound healing is a complex physiological process that requires the efforts of various cell types and signaling pathways and often results in thickened collagen-enriched healed tissue called a scar. Therefore, the identification of the mechanism of cutaneous wound healing is necessary and has great value in providing better treatment. Here, we demonstrated that MMP-1 inhibition could promote cell proliferation in dermal fibroblasts via the MTT assay. Meanwhile, we investigated cell migration by flow cytometry and tested type I collagenase activity. We found that MMP-1 inhibition promoted cell proliferation and inhibited cell migration and type I collagenase activity. In conclusion, our study demonstrated that MMP-1 might be a potential therapeutic target in cutaneous wound healing.

MicroRNAs in the skin: role in development, homoeostasis and regeneration

The skin is the largest organ of the integumentary system and possesses a vast number of functions. Due to the distinct layers of the skin and the variety of cells which populate each, a tightly regulated network of molecular signals control development and regeneration, whether due to programmed cell termination or injury. MicroRNAs (miRs) are a relatively recent discovery; they are a class of small non-coding RNAs which possess a multitude of biological functions due to their ability to regulate gene expression via post-transcriptional gene silencing. Of interest, is that a plethora of data demonstrates that a number of miRs are highly expressed within the skin, and are evidently key regulators of numerous vital processes to maintain non-aberrant functioning. Recently, miRs have been targeted as therapeutic interventions due to the ability of synthetic 'antagomiRs' to down-regulate abnormal miR expression, thereby potentiating wound healing and attenuating fibrotic processes which can contribute to disease such as systemic sclerosis (SSc). This review will provide an introduction to the structure and function of the skin and miR biogenesis, before summarizing the literature pertaining to the role of miRs. Finally, miR therapies will also be discussed, highlighting important future areas of research.