Aberrant miR-21 and miR-200b expression and its pro-fibrotic potential in hypertrophic scars

Exosomes and microRNAs: insights into their roles in thermal-induced skin injury, wound healing and scarring

A burn is a type of injury to the skin or other tissues caused by heat, chemicals, electricity, sunlight, or radiation. Burn injuries have been proven to have the potential for long-term detrimental effects on the human body. The conventional therapeutic approaches are not able to effectively and easily heal these burn wounds completely. The main potential drawbacks of these treatments include hypertrophic scarring, contracture, infection, necrosis, allergic reactions, prolonged healing times, and unsatisfactory cosmetic results. The existence of these drawbacks and limitations in current treatment approaches necessitates the need to search for and develop better, more efficient therapies. The regenerative potential of microRNAs (miRNAs) and the exosomal miRNAs derived from various cell types, especially stem cells, offer advantages that outweigh traditional burn wound healing treatment procedures. The use of multiple types of stem cells is gaining interest due to their improved healing efficiency for various applications. Stem cells have several key distinguishing characteristics, including the ability to promote more effective and rapid healing of burn wounds, reduced inflammation levels at the wound site, and less scar tissue formation and fibrosis. In this review, we have discussed the stages of wound healing, the role of exosomes and miRNAs in improving thermal-induced wounds, and the impact of miRNAs in preventing the formation of hypertrophic scars. Research studies, pre-clinical and clinical, on the use of different cell-derived exosomal miRNAs and miRNAs for the treatment of thermal burns have been documented from the year 2000 up to the current time. Studies show that the use of different cell-derived exosomal miRNAs and miRNAs can improve the healing of burn wounds. The migration of exosomal miRNAs to the site of a wound leads to inhibition of apoptosis, induction of autophagy, re-epithelialization, granulation, regeneration of skin appendages, and angiogenesis. In conclusion, this study underscores the importance of integrating miRNA and exosome research into treatment strategies for burn injuries, paving the way for novel therapeutic approaches that could significantly improve patient outcomes and recovery times.

The Role of Tenascin-C in Hypertrophic Scar Formation: Insights from Cell and Animal Experiments

Background

Hypertrophic scars (HS) are dermal diseases characterized by excessive fibroblast proliferation and collagen deposition following burns or trauma. While Tenascin-C (TNC)'s role in promoting visceral fibrosis has been established, its impact on skin tissue fibrosis remains unclear. This study aims to investigate the effects of TNC on HS.

Methods

RNA sequence and IHC techniques were used to examine the upregulation of TNC gene in human hypertrophic scar tissue compared to normal tissues. Knockdown of TNC in Human skin fibroblasts (HFF-1) cells was achieved, and expression of Col1 and Col3 was evaluated using qPCR. Sirius red collagen staining assessed impact on total collagen content and ECM deposition. Effects on cell proliferation and migration were investigated through cck-8 and cell scratch experiments. Lentivirus infection was used to knock out TNC, and resulting samples were injected into ear wound of rabbits. Effects of TNC knockout on ear scar formation were measured using digital morphology, ultrasound, SEI, H&E, and Masson trichrome methods.

Results

Cell experiments: downregulation of TNC decreased Col1 and Col3 expression, leading to reduced collagen production and extracellular matrix deposition. It did not affect HFF-1 cell proliferation and migration. Animal experiments: TNC knockdown promoted wound healing and reduced collagen deposition in rabbit ears.

Conclusion

This study suggests that knocking down TNC inhibits collagen formation and extracellular matrix deposition, thereby inhibiting hypertrophic scar formation. Therefore, TNC can be considered a potential biomarker for HS formation and may offer promising treatment strategies for clinical management of hypertrophic scars.

Role of myocardial microRNAs in the long-term ventricular remodelling of patients with aortic stenosis

Aims

We hypothesize that miRs are key players in the dynamics of the hypertrophy phenotype in aortic stenosis (AS) patients. In our study, we aimed to identify the transcriptional patterns (protein-coding transcripts and miRs) from myocardial sample biopsies that could be associated with the absence of left ventricular (LV) mass regression after aortic valve replacement (AVR) in patients with severe AS and LV hypertrophy.

Methods and results

We prospectively included 40 patients with severe AS, LV hypertrophy, and preserved ejection fraction undergoing AVR. Myocardial biopsies obtained during surgery were analysed for transcriptomic analysis performed by next-generation sequencing. At a 1-year follow-up, no hypertrophy reversal was observed in about half of the patients in the absence of patient-prosthesis mismatch and prosthesis dysfunction of uncontrolled hypertension. Predictors of mass regression were assessed from clinical, echocardiographic, and biochemical variables as well as from 300 miRs obtained from myocardial specimens, allowing the identification 29 differentially expressed. miR-4709-3p was found as a positive independent predictor of hypertrophy regression together with high-sensitivity troponin T (cTNT-hs) as a negative predictor. Gene transcripts RFX1, SIX5, MAPK8IF3, and PKD1 were predicted as simultaneous targets of five upregulated miRs suggesting its importance in LV hypertrophy.

Conclusion

In our cohort, tissue miR-4709-3p and cTNT-hs were independent predictors of hypertrophy regression. The hypertrophy reversal process will likely depend from a complex network where miRNAs may have an important role, allowing a potential opportunity for therapy.

Helicobacter pylori-activated fibroblasts as a silent partner in gastric cancer development

The discovery of Helicobacter pylori (Hp) infection of gastric mucosa leading to active chronic gastritis, gastroduodenal ulcers, and MALT lymphoma laid the groundwork for understanding of the general relationship between chronic infection, inflammation, and cancer. Nevertheless, this sequence of events is still far from full understanding with new players and mediators being constantly identified. Originally, the Hp virulence factors affecting mainly gastric epithelium were proposed to contribute considerably to gastric inflammation, ulceration, and cancer. Furthermore, it has been shown that Hp possesses the ability to penetrate the mucus layer and directly interact with stroma components including fibroblasts and myofibroblasts. These cells, which are the source of biophysical and biochemical signals providing the proper balance between cell proliferation and differentiation within gastric epithelial stem cell compartment, when exposed to Hp, can convert into cancer-associated fibroblast (CAF) phenotype. The crosstalk between fibroblasts and myofibroblasts with gastric epithelial cells including stem/progenitor cell niche involves several pathways mediated by non-coding RNAs, Wnt, BMP, TGF-β, and Notch signaling ligands. The current review concentrates on the consequences of Hp-induced increase in gastric fibroblast and myofibroblast number, and their activation towards CAFs with the emphasis to the altered communication between mesenchymal and epithelial cell compartment, which may lead to inflammation, epithelial stem cell overproliferation, disturbed differentiation, and gradual gastric cancer development. Thus, Hp-activated fibroblasts may constitute the target for anti-cancer treatment and, importantly, for the pharmacotherapies diminishing their activation particularly at the early stages of Hp infection.

MicroRNAs involved in human skin burns, wound healing and scarring

MicroRNAs are small, non-coding RNAs that regulate gene expression, and consequently protein synthesis. Downregulation and upregulation of miRNAs and their corresponding genes can alter cell apoptosis, proliferation, migration and fibroproliferative responses following a thermal injury. This review summarises the evidence for altered human miRNA expression post-burn, and during wound healing and scarring. In addition, the most relevant miRNA targets and their roles in potential pathways are described. Previous studies using molecular techniques have identified 197 miRNAs associated with human wound healing, burn wound healing and scarring. Five miRNAs alter the expression of fibroproliferative markers, proliferation and migration of fibroblasts and keratinocytes post-burn: hsa-miR-21 and hsa-miR-31 are increased after wounding, and hsa-miR-23b, hsa-miR-200b and hsa-let-7c are decreased. Four of these five miRNAs are associated with the TGF-β pathway. In the future, large scale, in vivo, longitudinal human studies utilising a range of cell types, ethnicity and clinical healing outcomes are fundamental to identify burn wound healing and scarring specific markers. A comprehensive understanding of the underlying pathways will facilitate the development of clinical diagnostic or prognostic tools for better scar management and the identification of novel treatment targets for improved healing outcomes in burn patients.

Pirfenidone promotes the levels of exosomal miR-200 to down-regulate ZEB1 and represses the epithelial-mesenchymal transition of non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is the malignancy with highest mortality and morbidity. Cancer-associated fibroblasts (CAFs) are the most abundant stromal cells in the tumor microenvironment of NSCLC. This research is performed to explore the biological functions of pirfenidone (PFD) to repress the malignant phenotypes of NSCLC cells, and its regulatory effects on exosomal microRNA-200 (exo-miR-200) derived from CAFs. In the present work, we report that, exo-miR-200 secreted by CAFs restrains the migration, invasion and epithelial-mesenchymal transition (EMT) of NSCLC cells; PFD treatment promotes the secretion of exo-miR-200 from CAFs and enhances the tumor-suppressive properties of exo-miR-200 on NSCLC cells; zinc finger E-box binding homeobox 1 (ZEB1) is identified as a target of miR-200, and PFD treatment repressed the expression of ZEB1 in NSCLC cells via inducing the expression and secretion of miR-200 in CAFs. In conclusion, PFD-induced miR-200 overexpression in CAFs inhibits ZEB1 expression in NSCLC cells, and thus decelerates the migration, invasion and EMT process. Our study may provide clues for the treatment of NSCLC.

The emerging therapeutic targets for scar management: genetic and epigenetic landscapes

Background

Wound healing is a complex process including hemostasis, inflammation, proliferation, and remodeling during which an orchestrated array of biological and molecular events occurs to promote skin regeneration. Abnormalities in each step of the wound healing process lead to reparative rather than regenerative responses, thereby driving the formation of cutaneous scar. Patients suffering from scars represent serious health problems such as contractures, functional and esthetic concerns as well as painful, thick, and itchy complications, which generally decrease the quality of life and impose high medical costs. Therefore, therapies reducing cutaneous scarring are necessary to improve patients' rehabilitation.

Summary

Current approaches to remove scars, including surgical and nonsurgical methods, are not efficient enough, which is in principle due to our limited knowledge about underlying mechanisms of pathological as well as the physiological wound healing process. Thus, therapeutic interventions focused on basic science including genetic and epigenetic knowledge are recently taken into consideration as promising approaches for scar management since they have the potential to provide targeted therapies and improve the conventional treatments as well as present opportunities for combination therapy. In this review, we highlight the recent advances in skin regenerative medicine through genetic and epigenetic approaches to achieve novel insights for the development of safe, efficient, and reproducible therapies and discuss promising approaches for scar management.

Key Message

Genetic and epigenetic regulatory switches are promising targets for scar management, provided the associated challenges are to be addressed.

MicroRNA-365a/b-3p as a Potential Biomarker for Hypertrophic Scars

The clinical aspects of hypertrophic scarring vary according to personal constitution and body part. However, the mechanism of hypertrophic scar (HS) formation remains unclear. MicroRNAs (miRNAs) are known to contribute to HS formation, however, their detailed role remains unknown. In this study, candidate miRNAs were identified and analyzed as biomarkers of hypertrophic scarring for future clinical applications. HSfibroblasts and normal skin fibroblasts from patients were used for profiling and validation of miRNAs. An HS mouse model with xenografted human skin on nude mice was established. The miRNA expression between normal human, normal mouse, and mouse HS skin tissues was compared. Circulating miRNA expression levels in the serum of normal mice and mice with HSs were also analyzed. Ten upregulated and twenty-one downregulated miRNAs were detected. Among these, miR-365a/b-3p and miR-16-5p were identified as candidate miRNAs with statistically significant differences; miR-365a/b-3p was significantly upregulated (p = 0.0244). In mouse studies, miR-365a/b-3p expression levels in skin tissue and serum were higher in mice with HSs than in the control group. These results indicate that miRNAs contribute to hypertrophic scarring and that miR-365a/b-3p may be considered a potential biomarker for HS formation.

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.

MicroRNA-18a-5p represses scar fibroblast proliferation and extracellular matrix deposition through regulating Smad2 expression

The aim of the present study was to investigate the expression and role of microRNA-18a-5p (miR-18a-5p) during the formation of hypertrophic scar (HS), and to further explore the molecular mechanisms involved. Downregulation of miR-18a-5p in HS tissues and human HS fibroblasts (hHSFs) was detected by reverse transcription-quantitative polymerase chain reaction. The binding sites between miR-18a-5p and the 3'-untranslated region of SMAD family member 2 (Smad2) were predicted by TargetScan and confirmed by dual-luciferase reporter assay. To investigate the role of miR-18a-5p in HS formation, the effects of miR-18a-5p downregulation or upregulation on hHSFs were subsequently determined. Cell proliferation was detected by an MTT assay, while cell apoptosis was measured by flow cytometry. In addition, the protein expression levels of Smad2, Collagen I (Col I) and Col III were examined by western blot assay. The findings indicated that miR-18a-5p downregulation in hHSFs significantly promoted the cell proliferation, decreased cell apoptosis and enhanced the expression levels of Smad2, Col I and Col III protein and mRNA, whereas miR-18a-5p upregulation in hHSFs exerted opposite effects. Notably, the effects of miR-18a-5p upregulation on hHSFs were eliminated by Smad2 upregulation. In conclusion, the data indicated that miR-18a-5p was downregulated during HS formation, and its upregulation repressed scar fibroblast proliferation and extracellular matrix deposition by targeting Smad2. Therefore, miR-18a-5p may serve as a novel therapeutic target for the treatment of HS.

MicroRNAs as biomarkers of atrophic scarring in acne: a cross-sectional analysis of 41 patients

BACKGROUND

Acne is the commonest inflammatory dermatosis seen worldwide. Atrophic acne scarring is a frequent complication, which can arise from acne of any severity. Micro (mi)RNAs are noncoding RNA molecules of 19-25 nucleotides that function as post-transcriptomic mediators of gene expression. They have demonstrated differential expression in various pathologies, such as eczema and psoriasis, allowing for a unique miRNA 'signature' profile to be established for different disease states.

AIM

To establish a miRNA signature for acne, and acne-associated atrophic scarring and to identify if a pattern of circulating miRNA is evident in patients who are prone to scarring.

METHODS

In total, 41 participants were consecutively recruited to this study. Circulating miRNA was quantified from plasma samples in all 41 patients, while in 8 patients, and in a further validation cohort of 9 patients, whole miRNAome was undertaken from tissue specimens, which included lesional, normal and where present, scarred skin.

RESULTS

Three miRNAs, miR-223, miR-21 and miR-150, were statistically significantly overexpressed in acne lesions, and notably, in clinically uninvolved skin in participants prone to scarring. In this subgroup, we also found statistically significantly elevated levels of circulating miRNA-21 and miRNA-150.

CONCLUSION

The presence of elevated levels of these specific miRNAs in the serum of patients with acne raises the potential of a blood test to identify those at risk of scarring, allowing for earlier intervention with effective therapy.

MiR-210-5p regulates STAT3 activation by targeting STAT5A in the differentiation of dermal fibroblasts

Elucidating the molecular mechanism of the microRNAs in skin fibrosis is critical for identifying a novel therapeutic strategy for hypertrophic scar (HS). In this study, it was shown that miR-210-5p is induced by TGFβ, and that overexpression of miR-210-5p promoted the differentiation of human dermal fibroblasts (HDFs) into myofibroblasts. STAT5A is required for TGFβ-induced STAT3 activity. Here, we show that miR-210-5p attenuated TGFβ-induced STAT3 signaling pathway by suppressing the expression of STAT5A. Taken together, the present study suggests that TGFβ-induced miR-210-5p reduced STAT5A expression, leading to aberrant activation of STAT3, and facilitate skin fibrosis in HDFs.

MicroRNA-9-5p inhibits proliferation and induces apoptosis of human hypertrophic scar fibroblasts through targeting peroxisome proliferator-activated receptor β

Hypertrophic scar (HS) is a dermal fibro-proliferative disorder result from abnormal wound healing after skin injury. MicroRNA-9-5p (miR-9-5p) has been reported to be upregulated and closely related to collagen proteins in human dermal fibroblasts. However, the correlation and possible mechanism between miR-9-5p and HS require further investigation. The expressions of miR-9-5p in HS tissues and HS fibroblasts were detected by quantitative real-time PCR (RT-qPCR). The expression level of peroxisome proliferator-activated receptor β (PPARβ) was measured by RT-qPCR assay. The protein levels of PPARβ, α-SMA, Vimentin, COL1A, cyclin D1, bcl-2, and bax were detected by western blot assay. The effect of miR-9-5p and PPARβ on HS fibroblasts proliferation and apoptosis were detected by cell counting kit-8 (CCK-8) and flow cytometry assays. The interaction between miR-9-5p and PPARβ was predicted by TargetScan, and then confirmed by dual-luciferase reporter assay. MiR-9-5p expression was downregulated in HS tissues and HS fibroblasts. MiR-9-5p inhibited the levels of extracellular matrix-associated genes (α-SMA, Vimentin, COL1A) in HS fibroblasts. MiR-9-5p repressed proliferation and induced apoptosis of HS fibroblasts. PPARβ is a target gene of miR-9-5p. The silencing of PPARβ expression hindered proliferation and expedited apoptosis of HS fibroblasts. MiR-9-5p suppressed proliferation and promoted apoptosis of HS fibroblasts by targeting PPARβ. In this paper, we firstly disclosed that miR-9-5p hampered extracellular matrix deposition and proliferation, and induced apoptosis by targeting PPARβ in HS fibroblasts. Our findings provided a new role of miR-9-5p/PPARβ in the occurrence and development of HS fibroblasts, promising a new target for HS.

Summary: Our findings provided a new role of miR-9-5p/PPAR in the occurrence and development of HS fibroblasts, promising a new target for HS.

Inhibition of sphingosine kinase 2 attenuates hypertrophic scar formation via upregulation of Smad7 in human hypertrophic scar fibroblasts

The aims of the present study were to investigate the role of sphingosine kinase 2 (Sphk2) in hypertrophic scar (HS) formation and its underlying mechanisms. The expression levels of Sphk2 and Smad7 in HS tissues and healthy skin tissues of patients undergoing plastic surgery were determined using immunohistochemical staining. Subsequently, the expression levels of Sphk2 and collagen I in human embryonic skin fibroblasts (control) and human HS fibroblasts (HSF) were detected using western blot analysis and immunofluorescence assay, respectively. Following Sphk2 silencing, Smad7 overexpression or both Sphk2 and Smad7 silencing, HSF proliferative ability was assessed using Cell Counting Kit‑8 assay and proliferation‑associated proteins were evaluated using western blot analysis. In addition, the level of apoptosis in HSF was assessed using flow cytometry and expression levels of apoptotic‑associated proteins were determined using western blotting. Furthermore, the expression levels of collagen I and proteins in the TGF‑β1/Smad signaling pathway were detected using western blot analysis. The results indicated that the expression of Sphk2 was significantly increased, while Smad7 expression was decreased in HS tissue. Moreover, the upregulation of Sphk2 and collagen I expression levels was identified in HSF. The present results also indicated that Sphk2 silencing or Smad7 overexpression inhibited proliferation, but promoted apoptosis of HSF, coupled with changes in the expression levels of proliferation‑associated proteins, with an increase in p21 and a decrease in cyclin D1 expression levels, and apoptosis‑associated proteins, with an increase in Bax and cleaved caspase‑3, and a decrease in Bcl‑2, which were reversed following transfection with both Sphk2 and Smad7 using small interfering RNA in HSF. In addition, the expression levels of transforming growth factor‑β1, phosphorylated (p)‑Smad2, p‑Smad3 and collagen I were reduced following Sphk2 silencing or Smad7 overexpression, which were abolished by silencing both Sphk2 and Smad7. Collectively, the present results indicated that inhibition of Sphk2 attenuated HS formation via upregulation of Smad7 expression, thus Sphk2 may serve as a potential therapeutic target for the treatment of HS.

Biological approaches for hypertrophic scars

Scar formation is usually the pathological consequence of skin trauma. And hypertrophic scars (HSs) frequently occur in people after being injured deeply. HSs are unusually considered as the result of tissue contraction and excessive extracellular matrix component deposition. Myofibroblasts, as the effector cells, mainly differentiated from fibroblasts, play the crucial role in the pathophysiology of HSs. A number of growth factors, inflammatory cytokines involved in the process of HS occurrence. Currently, with in-depth exploration and clinical research of HSs, various creative and effective treatments budded. In here, we summarize the progress in the molecular mechanism of HSs, and review the available biotherapeutic methods for their pathophysiological characteristics. Additionally, we further prospected that the comprehensive therapy may be more suitable for HS treatment.

Anti-miR-200b promotes wound healing by regulating fibroblast functions in a novel mouse model

MicroRNA-200b (miR-200b) down-regulation has been found in wound-healing tissues. Fibroblasts are the predominant cells that orchestrate the production of collagen in wound healing. However, it is still unclear whether miR-200b can affect the wound healing by regulating the fibroblasts' function. The current rodent wound-healing models are not ideal due to their marked difference in structure compared with the human skin. In this study, we demonstrated that the murine plantar skin had similar anatomical features to the human skin. Using this model, the gain/loss-of-function studies showed that miR-200b caused a significantly delayed wound healing in vivo. Furthermore, using cell proliferation, migration and collagen synthesis assays, we found that miR-200b attenuated cell proliferation, migration and collagen synthesis of fibroblasts, which are critical aspects of wound healing. miR-200b also decreased the expression of Zeb1. Collectively, we established a new murine plantar skin model for the investigation of wound healing, and based on it we found that miR-200b affected the wound healing by regulating the biological function of fibroblasts, which provided a new insight for wound healing.

MicroRNA-130a has pro-fibroproliferative potential in hypertrophic scar by targeting CYLD

Hypertrophic scars are dermal fibrosis diseases that protrude from the surface of the skin and irregularly extend to the periphery, seriously affecting the appearance and limb function of the patient. In this study, we found that microRNA-130a (miR-130a) was increased in hypertrophic scar tissues and derived primary fibroblasts, accompanied by up-regulation of collagen1/3 and α-SMA. Inhibition of miR-130a in hypertrophic scars fibroblasts suppressed the expression of collagen1/3 and α-SMA as well as the cell proliferation. Bioinformatics analysis combined with luciferase reporter gene assay results indicated that CYLD was a target gene of miR-130a, and the miR-130a mimic could reduce the level of CYLD. In contrast to miR-130a, the expression of CYLD was downregulated in hypertrophic scars and their derived fibroblasts. Overexpressing CYLD inhibited the expression of collagen 1/3 and α-SMA, slowed cell proliferation, and inhibited Akt activity. As expected, further study showed that the overexpression of CYLD could prevent the pro-fibroproliferative effects of miR-130a. Consistent with the in vitro results, the inhibitor of miR-130a effectively ameliorated excessive collagen deposition in bleomycin-induced skin fibrosis mouse model. Taken together, our results indicate that miR-130a promotes collagen secretion, myofibroblast transformation and cell proliferation by targeting CYLD and enhancing Akt activity. Therefore, the miR-130a/CYLD/Akt pathway may serve as a novel entry point for future skin fibrosis research.

MicroRNA-205-5p regulates extracellular matrix production in hyperplastic scars by targeting Smad2

Hypertrophic scar (HS) formation is the result of poor skin-wound healing. At present, the pathogenesis of HS formation is largely unclear. Micro (miR)RNAs have important effects on a variety of biological and pathological processes. The role of miRNA in HS formation remains largely unclear. The present study aimed to investigate the role of miR-205-5p in HS, and explore the underlying molecular mechanism. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to determine the expression of miR-205-5p in HS. Western blot assay and RT-qPCR were performed to assess the expression of associated proteins and genes, respectively. TargetScan was performed to predict the target gene of miR-205-5p, and the luciferase reporter assay was applied to verify the prediction. The function of miR-205-5p on cell proliferation was detected using Cell Counting Kit-8 assay, and cell apoptosis was detected via flow cytometry. miR-205-5p expression was decreased in HS tissues and human hypertrophic scar fibroblasts (hHSFs). Mothers against decapentaplegic homolog (Smad)2 was significantly increased in HS tissues and HSFs, and it was directly targeted by miR-205-5p. Restoration of miR-205-5p suppressed HSF cell proliferation and induced cell apoptosis. It was also demonstrated that RAC-Alpha Serine/Threonine-Protein Kinase (AKT) phosphorylation and the expression of α-smooth muscle actin, collagen I and collagen III were inhibited by miR-205-5p. In addition, Smad2 weakened the effects of miR-205-5p on HSFs. In conclusion, miR-205-5p exhibited an important role in HS by targeting smad2 and suppressing the AKT pathway. These findings provide a clearer understanding of the mechanism for HS that may be used to develop novel treatments for HS.

High‑throughput sequencing reveals differentially expressed lncRNAs and circRNAs, and their associated functional network, in human hypertrophic scars

Growing evidence suggests that long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) are involved in the occurrence and development of tumors and fibrotic diseases. However, the integrated analysis of lncRNA and circRNA expression, alongside associated co-expression and competing endogenous RNA (ceRNA) networks, has not yet been performed in human hypertrophic scars (HS). The present study compared the expression levels of lncRNAs, circRNAs and mRNAs in human HS and normal skin tissues by high-throughput RNA sequencing. Numerous differentially expressed lncRNAs, circRNAs and mRNAs were detected. Subsequently, five aberrantly expressed lncRNAs and mRNAs, and six circRNAs were measured to verify the RNA sequencing results by reverse transcription-quantitative polymerase chain reaction. Furthermore, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed for the dysregulated genes, in order to elucidate their principal functions. In addition, a coding-noncoding gene co-expression (CNC) network and ceRNA network were constructed for specific significantly altered genes. The CNC network analysis suggested that AC048380.1 and LINC00299 were associated with metastasis-related genes, including inhibin subunit βA (INHBA), SMAD family member 7 (SMAD7), collagen type I α1 chain (COL1A1), transforming growth factor β3 (TGFβ3) and MYC proto-oncogene, bHLH transcription factor (MYC). Inhibitor of DNA binding 2 was associated with the lncRNAs cancer susceptibility 11, TGFβ3-antisense RNA 1 (AS1), INHBA-AS1, AC048380.1, LINC00299 and LINC01969. Circ-Chr17:50187014_50195976_-, circ-Chr17:50189167_50194626_-, circ-Chr17:50189167_ 50198002_- and circ-Chr17:50189858_50195330_- were also associated with INHBA, SMAD7, COL1A1, TGFβ3 and MYC. COL1A1 and TGFβ3 were associated with circ-Chr9:125337017_125337591_+ and circ-Chr12:120782654_120784593_-. The ceRNA network indicated that INHBA-AS1 and circ-Chr9:125337017_125337591_+ were ceRNAs of microRNA-182-5p targeting potassium voltage-gated channel subfamily J member 6, ADAM metallopeptidase with thrombospondin type 1 motif 18, SRY-box 11, MAGE family member L2, matrix metallopeptidase 16, thrombospondin 2, phosphodiesterase 11A and collagen type V a1 chain. These findings suggested that lncRNAs and circRNAs may act as ceRNAs, which are implicated in the pathophysiology and development of human HS, and lay a foundation for further insight into the novel regulatory mechanism of lncRNAs and circRNAs in hypertrophic scarring.

miR-200b ameliorates myofibroblast transdifferentiation in precancerous oral submucous fibrosis through targeting ZEB2

Oral submucous fibrosis (OSF) is a progressive scarring disease. MicroRNA-200b (miR-200b) has been reported as a tumour suppressor, but its role in the precancerous OSF remains unknown. In this study, we investigated the impact of miR-200b on myofibroblastic differentiation activity. Arecoline is a major areca nut alkaloid and has been employed to induce the elevated myofibroblast activity in human buccal mucosal fibroblasts (BMFs). Treatment of arecoline in BMFs dose-dependently reduced gene expression of miR-200b, which corresponded with the decreased expression of miR-200b in fBMFs. The arecoline-induced myofibroblast activities were abolished by overexpression of miR-200b in BMFs, and the same results were observed in fBMFs. In addition, α-SMA was inhibited by an increase in miR-200b. We further demonstrated that miR-200b-mediated decrease in ZEB2 led to down-regulation of α-SMA, vimentin. Loss of miR-200b resulted in enhanced collagen contraction and migration capabilities, and knockdown of ZEB2 reversed these phenomena. Lastly, we showed the expression of miR-200b was significantly less and ZEB2 was markedly higher in OSF tissues. These results suggested that down-regulation of miR-200b may contribute to the pathogenesis of areca quid-associated OSF through the regulation of ZEB2 and myofibroblast hallmarks.

MicroRNA-26a inhibits hyperplastic scar formation by targeting Smad2

Hypertrophic scar (HS) is a fibrotic disease in which excessive extracellular matrix forms due to the response of fibroblasts to tissue damage. Novel evidence suggests that microRNAs (miRNAs or miRs) may contribute to hypertrophic scarring; however, the role of miRNAs in HS formation remains unclear. In the present study, miR-26a was significantly downregulated in HS tissues and human HS fibroblasts (hHSFs) was detected by reverse transcription-quantitative analysis. TargetScan was used to predict that mothers against decapentaplegic homolog 2 (Smad2) is a potential target gene of miR-26a and a dual-luciferase reporter assay confirmed that Smad2 was a target gene of miR-26a. The expression of Smad2 was upregulated in HS tissues and hHSFs. Cell Counting Kit-8 and flow cytometry analyses demonstrated that the overexpression of miR-26a significantly suppressed the proliferation ability of hHSFs and the apoptotic rate of hHSFs was significantly upregulated in response to miR-26a mimic transfection. Furthermore, the expression of B-cell lymphoma-2 (Bcl-2)-associated X protein was increased and Bcl-2 expression was decreased following miR-26a mimic transfection. The expression of collagens I and III was significantly inhibited following treatment with miR-26a mimics in hHSF cells. Conversely, miR-26a inhibitors served an opposing role in hHSFs. Furthermore, Smad2 overexpression enhanced the expression of collagens I and c III; however, Smad2 silencing inhibited the expression of collagens I and c III. In conclusion, the results of the present study indicate that miR-26a inhibits HS formation by modulating proliferation and apoptosis ad well as inhibiting the expression of extracellular matrix-associated proteins by targeting Smad2.

Insights into the key roles of epigenetics in matrix macromolecules-associated wound healing

Extracellular matrix (ECM) is a dynamic network of macromolecules, playing a regulatory role in cell functions, tissue regeneration and remodeling. Wound healing is a tissue repair process necessary for the maintenance of the functionality of tissues and organs. This highly orchestrated process is divided into four temporally overlapping phases, including hemostasis, inflammation, proliferation and tissue remodeling. The dynamic interplay between ECM and resident cells exerts its critical role in many aspects of wound healing, including cell proliferation, migration, differentiation, survival, matrix degradation and biosynthesis. Several epigenetic regulatory factors, such as the endogenous non-coding microRNAs (miRNAs), are the drivers of the wound healing response. microRNAs have pivotal roles in regulating ECM composition during wound healing and dermal regeneration. Their expression is associated with the distinct phases of wound healing and they serve as target biomarkers and targets for systematic regulation of wound repair. In this article we critically present the importance of epigenetics with particular emphasis on miRNAs regulating ECM components (i.e. glycoproteins, proteoglycans and matrix proteases) that are key players in wound healing. The clinical relevance of miRNA targeting as well as the delivery strategies designed for clinical applications are also presented and discussed.

Aberrantly expressed long noncoding RNAs in hypertrophic scar fibroblasts in vitro: A microarray study

A hypertrophic scar is the result of abnormal repair of the body after trauma. Histopathologically, it is mostly the result of the excessive proliferation of fibroblasts and the accumulation of extracellular matrix. Accumulating evidence has demonstrated that long non-coding RNAs (lncRNAs) have a critical role in the regulation of gene expression and in the pathogenesis of diseases. However, the roles of lncRNAs in hypertrophic scars have remained elusive. The present study investigated the profiles of differentially expressed lncRNAs between fibroblasts derived from a hypertrophic scar and normal skin, and explored the possible mechanisms underlying the development of hypertrophic scars. Microarray data indicated that 6,104 lncRNAs and 2,952 mRNAs were differentially expressed. A set of differentially expressed transcripts as confirmed by reverse transcription-quantitative polymerase chain reaction. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed to determine the principal functions of the significantly deregulated genes. Furthermore, associated expression networks, including subgroup analysis, competing endogenous RNAs (ceRNAs) and coding-noncoding co-expression networks were constructed using bioinformatics methods. The homology between differentially expressed lncRNAs and mRNAs was assessed and two exon lncRNA were selected to explore their regulatory mechanisms. The ceRNA network inferred that NR_125715 acted as a competing endogenous RNA, bound to microRNA (miR)-141-3p, miR-200a-3p and miR-29 to regulate the expression of the miRs' targets, including transforming growth factor β2 (TGFB2). Similarly, NR_046402 acted as a competing endogenous RNA, which bound to miR-133a-3p.1 and miR-4469 to then regulate the expression of the miRs' targets, including DNA polymerase δ1, catalytic subunit (POLD1). In addition, co-expression analysis indicated that the expression of lncRNAs NR_125715 and NR_046402 was correlated with that of TGFB2 and POLD1 mRNA. The identification of these differentially expressed lncRNAs in the hypertrophic scar-derived fibroblasts in the present study, may provide novel insight into the functional interactions of lncRNA, miRNA and mRNA, and lead to novel theories for the pathogenesis and treatment of hypertrophic scars.

LncRNA COL1A2-AS1 inhibits the scar fibroblasts proliferation via regulating miR-21/Smad7 pathway

lncRNA COL1A2-AS1 (COL1A2 antisense RNA 1), a lncRNA overexpressed in hypertrophic scar, has been demonstrated to be involved in the hypertrophic scar formation. However, the mechanisms of lncRNA COL1A2-AS1 inhibiting the scar fibroblasts proliferation remains not well understood. In this study, we demonstrated that lncRNA COL1A2-AS1 was upregulated in hypertrophic scar tissue and fibroblasts, and suppressed fibroblasts proliferation by promoting Smad7 expression. Furthermore, we found that miR-21 was involved in lncRNA COL1A2-AS1-induced expression of Smad7, by which COL1A2-AS1 acted as endogenous sponge to adsorb miR-21 and in turn regulated Smad7 and a cascade of molecular to play a protective role in hypertrophic scar. In addition, overexpression of miR-21 attenuated COL1A2-AS1-mediated proliferation suppression of hypertrophic scar fibroblasts. In conclusion, our study demonstrated that COL1A2-AS1/miR-21/Smad pathway plays an important role in inhibiting hypertrophic scar formation, and suggested this novel pathway may be a new target for hypertrophic scar treatment.

MicroRNA-192 regulates hypertrophic scar fibrosis by targeting SIP1

Hypertrophic scar (HS) is a fibro-proliferative disorder which is characterized by excessive deposition of collagen and accumulative activity of myofibroblasts. Increasing evidences have demonstrated miRNAs play a pivotal role in the pathogenesis of HS. MiR-192 is closely associated with renal fibrosis, but its effect on HS formation and skin fibrosis remains unknown. In the study, we presented that miR-192 was up-regulated in HS and HS derived fibroblasts (HSFs) compared to normal skin (NS) and NS derived fibroblasts (NSFs), accompanied by the reduction of smad interacting protein 1 (SIP1) expression and the increase of Col1, Col3 and α-SMA levels. Furthermore, we confirmed SIP1 was a direct target of miR-192 by using luciferase reporter assays. Meanwhile, the overexpression of miR-192 increased the levels of Col1, Col3 and α-SMA. The synthesis of collagen and more positive α-SMA staining were also observed in bleomycin-induced dermal fibrosis model of BALB/c mice treated with subcutaneous miR-192 mimics injection, whereas the inhibition of miR-192 decreased the expression of Col1, Col3 and α-SMA. Moreover, SIP1 siRNA could enhance the levels of Col1, Col3 and α-SMA, showing that the effect of knockdown SIP1 was similar to miR-192 mimics, and the phenomenon manifested miR-192 regulated HS fibrosis by targeting SIP1. Together, our results indicated that miR-192 was a critical factor of HS formation and facilitated skin fibrosis by targeting directly SIP1.

Epithelial-to-mesenchymal transition transcription factors in cancer-associated fibroblasts

Beyond inducing epithelial‐to‐mesenchymal transcription (EMT), transcriptional factors of the Snail, ZEB and Twist families (EMT‐TFs) control global plasticity programmes affecting cell stemness and fate. Literature addressing the reactivation of these factors in adult tumour cells is very extensive, as they enable cancer cell plasticity and fuel both tumour initiation and metastatic spread. Incipient data reveal that EMT‐TFs are also expressed in fibroblasts, providing these with additional properties. Here, I will review recent reports on the expression of EMT‐TFs in cancer‐associated fibroblasts (CAFs). The new model suggests that EMT‐TFs can be envisioned as essential metastasis and chemoresistance‐promoting molecules, thereby enabling coordinated plasticity programmes in parenchyma and stroma–tumour compartments.

Role of the microRNA-29 family in fibrotic skin diseases

Fibrotic skin diseases are characterized by the accumulation of collagen. The hallmarks of fibrotic skin diseases are unbalanced fibroblast proliferation and differentiation, extracellular matrix production and transforming growth factor-β signalling. Numerous studies have investigated the possibility that microRNAs (miRNAs or miRs) are involved in the pathogenesis of certain fibrotic diseases, including skin, heart, lung and liver diseases. miRNAs are a class of small non-coding RNAs, which modify gene expression by binding to target messenger RNA (mRNA) and blocking the translation or inducing the degradation of target mRNA. The biological relevance of miRNAs has been investigated in physiological and pathological conditions, and there is increasing evidence that the miR-29 family is associated with fibrotic diseases. The aim of the present review is to provide an up-to-date summary of current knowledge on the latest developments associated with the miR-29 family and fibrotic skin diseases.

Non-Coding RNAs: The New Insight on Hypertrophic Scar

Hypertrophic scarring (HS), a fibroproliferative disorder caused by abnormal wound healing after skin injury, is characterized by excessive deposition of extracellular matrix and invasive growth of fibroblasts. Numerous studies have reported that non-coding RNAs (ncRNAs) including microRNAs (miRNAs, miRs) and long non-coding RNAs (lncRNAs) play important roles in HS formation. Exploring non-coding RNA-based methods to treat scar would be instrumental for devising new effective therapies against scar. J. Cell. Biochem. 118: 1965-1968, 2017. © 2017 Wiley Periodicals, Inc.

Non-Coding RNAs: New Players in Skin Wound Healing

Significance: Wound healing is a basic physiological process that is utilized to keep the integrity of the skin. Impaired wound repair, such as chronic wounds and pathological scars, presents a major health and economic burden worldwide. To date, efficient targeted treatment for these wound disorders is still lacking, which is largely due to our limited understanding of the biological mechanisms underlying these diseases. Research driven around discovering new therapies for these complications is, therefore, an urgent need. Recent Advances: The vast majority of the human genome is transcribed to RNAs that lack protein-coding capacity. Intensive research in the recent decade has revealed that these non-coding RNAs (ncRNAs) function as important regulators of cellular physiology and pathology, which makes them promising therapeutic and diagnostic entities. Critical Issues: A class of short ncRNAs, microRNAs, has been found to be indispensable for all the phases of skin wound healing and plays important roles in the pathogenesis of wound complications. The role of long ncRNAs (lncRNA) in skin wound healing remains largely unexplored. Recent studies revealed the essential role of lncRNAs in epidermal differentiation and stress response, indicating their potential importance for skin wound healing, which warrants future research. Future Directions: An investigation of ncRNAs will add new layers of complexity to our understanding of normal skin wound healing as well as to the pathogenesis of wound disorders. Development of ncRNA-based biomarkers and treatments is an interesting and important avenue for future research on wound healing.

MicroRNA-143-3p inhibits hyperplastic scar formation by targeting connective tissue growth factor CTGF/CCN2 via the Akt/mTOR pathway

Post-traumatic hypertrophic scar (HS) is a fibrotic disease with excessive extracellular matrix (ECM) production, which is a response to tissue injury by fibroblasts. Although emerging evidence has indicated that miRNA contributes to hypertrophic scarring, the role of miRNA in HS formation remains unclear. In this study, we found that miR-143-3p was markedly downregulated in HS tissues and fibroblasts (HSFs) using qRT-PCR. The expression of connective tissue growth factor (CTGF/CCN2) was upregulated both in HS tissues and HSFs, which is proposed to play a key role in ECM deposition in HS. The protein expression of collagen I (Col I), collagen III (Col III), and α-smooth muscle actin (α-SMA) was obviously inhibited after treatment with miR-143-3p in HSFs. The CCK-8 assay showed that miR-143-3p transfection reduced the proliferation ability of HSFs, and flow cytometry showed that either early or late apoptosis of HSFs was upregulated by miR-143-3p. In addition, the activity of caspase 3 and caspase 9 was increased after miR-143-3p transfection. On the contrary, the miR-143-3p inhibitor was demonstrated to increase cell proliferation and inhibit apoptosis of HSFs. Moreover, miR-143-3p targeted the 3'-UTR of CTGF and caused a significant decrease of CTGF. Western blot demonstrated that Akt/mTOR phosphorylation and the expression of CTGF, Col I, Col III, and α-SMA were inhibited by miR-143-3p, but increased by CTGF overexpression. In conclusion, we found that miR-143-3p inhibits hypertrophic scarring by regulating the proliferation and apoptosis of human HSFs, inhibiting ECM production-associated protein expression by targeting CTGF, and restraining the Akt/mTOR pathway.