Pathogenesis Of Hypertrophic Scars Research Articles

Role of Emerin in regulating fibroblast differentiation and migration at the substrate of stiffness coupled topology.

In hypertrophic scars, the differentiation and migration of fibroblasts are influenced by the extracellular matrix microenvironment, which includes factors such as stiffness, restraint, and tensile force. These mechanical stresses incite alterations in cell behavior, accompanied by cytoskeletal protein reorganization. However, the role of nucleo-skeletal proteins in this context remains underexplored. In this study, we use a polyacrylamide hydrogel (PAA) to simulate the mechanical stress experienced by cells in scar tissue and investigate the impact of Emerin on cell behavior. We utilize atomic force microscopy (AFM) and RNA interference technology to analyze cell differentiation, migration, and stiffness. Our findings reveal that rigid substrates and cellular restriction elevate Emerin expression and diminish differentiation. Conversely, reducing Emerin expression leads to attenuated cell differentiation, where stiffness and constraining factors exert no notable influence. Furthermore, a softening of cells and an enhanced migration rate are also markedly observed. These observations indicate that variations in nuclear skeletal proteins, prompted by diverse matrix microenvironments, play a pivotal role in the pathogenesis of hypertrophic scars (HSs). This research offers novel insights and a reference point for understanding scar fibrosis formation mechanisms and preventing fibrosis.

Using network pharmacology to discover potential drugs for hypertrophic scars.

Hypertrophic scarring is a disease of abnormal skin fibrosis caused by excessive fibroblast proliferation. Existing drugs have not achieved satisfactory therapeutic effects. To explore the molecular pathogenesis of hypertrophic scars and screen effective drugs for their treatment. Existing human hypertrophic scar RNA sequencing data were utilized to search for hypertrophic scar-related gene modules and key genes through weighted gene co-expression network analysis (WGCNA). Candidate compounds were screened in a compound library. Potential drugs were screened by molecular docking and verified in human hypertrophic scar fibroblasts and a mouse mechanical force hypertrophic scar model. WGCNA showed that hypertrophic scar-associated gene modules influence focal adhesion, the transforming growth factor (TGF)-β signalling pathway and other biologic pathways. Integrin β1 (ITGB1) is the hub protein. Among the candidate compounds obtained by computer virtual screening and molecular docking, crizotinib, sorafenib and SU11274 can inhibit the proliferation and migration of human hypertrophic scar fibroblasts and profibrotic gene expression. Crizotinib had the best effect on hypertrophic scar attenuation in mouse models. At the same time, mouse ITGB1 small interfering RNA can also inhibit mouse scar hyperplasia. ITGB1 and TGF-β signalling pathways are important for hypertrophic scar formation. Crizotinib could be a potential treatment drug for hypertrophic scars.

P06 A novel drug combination produces a synergistic effect when inhibiting myofibroblast transformation in an in vitro model of hypertrophic scarring

Abstract Introduction and aims Hypertrophic scars affect 91% of patients with burns and yet, there is currently no effective treatment for their prevention. Myofibroblasts are key cells in the pathogenesis of hypertrophic scars, with the inhibition of myofibroblast transformation having been suggested as an effective therapeutic strategy. We have previously screened 1954 drugs approved by the Food and Drug Administration to identify any that could inhibit myofibroblast transformation. Using this data, the aim of this study was to investigate the individual and combined antimyofibroblast effect of two drug classes. Methods Primary human fibroblasts were isolated from the scars of patients with burns, with myofibroblast transformation induced using transforming growth factor (TGF)-β1. Concentration-response curves for drug-class A and drug-class B were constructed at a range of concentrations (0.03–300 µmol L–1), with the In-Cell enzyme-linked immunosorbent assay method used to measure α-smooth muscle actin (α-SMA) expression. Combination experiments were carried out through construction of a concentration-response curve for drug-class A (0.03–100 µmol L–1) in the presence of 3 µmol L–1 of drug-class B. Results Both drug classes showed a concentration-dependent antimyofibroblast effect with an IC50 range of 12.2–120.1 µmol L–1 for drug-class A and 1.4–16.7 µmol L–1 for drug-class B. When given in combination the two classes of drugs produced a synergistic effect at all concentrations up to 10 µmol L–1. For example, an 18% reduction α-SMA expression was expected with 1 µmol L–1 of drug-class A and 3 µmol L–1 of drug-class B; however, a 24% reduction in α-SMA expression was observed instead. Conclusions This is the first study to identify this synergistic effect between these two drug classes, and therefore this novel drug combination could be developed for the prevention of hypertrophic scar formation.

Global proteomic analysis reveals lysine succinylation is involved in the pathogenesis of hypertrophic scar

Lysine succinylation (Ksucc) is a recently identified posttranslational modification that is involved in many diseases. This study examined the role of Ksucc in the pathogenesis of hypertrophic scar (HS). The presence of Ksucc in human skin was measured by immunoblotting. Ksucc occurs in many skin proteins ranging from 25 to 250 kDa, and higher levels of Ksucc are found in HS skin than in normal skin. An immunoaffinity approach coupled with LC–MS/MS was used to characterize the first succinylome of human skin, and 159 Ksucc sites in 79 proteins were identified. Among these, there were 38 increased succinylated sites in 29 proteins but no decreased succinylated sites in HS compared with normal skin. A parallel reaction monitoring assay was performed to validate the results of the succinylome and showed that the levels of Ksucc in decorin and collagens, which are involved in the pathogenesis of HS, were increased in HS than in normal skin. In addition, increasing the level of Ksucc enhanced cell proliferation and upregulated the expression of fibrosis markers (α-SMA, COL1, and COL3) in human skin fibroblasts. Our results provide global insights into the functional role of Ksucc in hypertrophic scarring.

Assessment of Micro RNAs 31 In Pathogenesis of Hypertrophic Scar

Assessment of Micro RNAs 31 In Pathogenesis of Hypertrophic Scar

Deciphering the contributions of cuproptosis in the development of hypertrophic scar using single-cell analysis and machine learning techniques.

Hypertrophic scar (HS) is a chronic inflammatory skin disease characterized by excessive deposition of extracellular matrix, but the exact mechanisms related to its formation remain unclear, making it difficult to treat. This study aimed to investigate the potential role of cuproptosis in the information of HS. To this end, we used single-cell sequencing and bulk transcriptome data, and screened for cuproptosis-related genes (CRGs) using differential gene analysis and machine learning algorithms (random forest and support vector machine). Through this process, we identified a group of genes, including ATP7A, ULK1, and MTF1, as novel therapeutic targets for HS. Furthermore, quantitative real-time polymerase chain reaction (qRT-PCR) was conducted to confirm the mRNA expression of ATP7A, ULK1, and MTF1 in both HS and normal skin (NS) tissues. We also constructed a diagnostic model for HS and analyzed the immune infiltration characteristics. Additionally, we used the expression profiles of CRGs to perform subgroup analysis of HS. We focused mainly on fibroblasts in the transcriptional profile at single-cell resolution. By calculating the cuproptosis activity of each fibroblast, we found that cuproptosis activity of normal skin fibroblasts increased, providing further insights into the pathogenesis of HS. We also analyzed the cell communication network and transcription factor regulatory network activity, and found the existence of a fibroblast-centered communication regulation network in HS, where cuproptosis activity in fibroblasts affects intercellular communication. Using transcription factor regulatory activity network analysis, we obtained highly active transcription factors, and correlation analysis with CRGs suggested that CRGs may serve as potential target genes for transcription factors. Overall, our study provides new insights into the pathophysiological mechanisms of HS, which may inspire new ideas for the diagnosis and treatment.

Adipose-Derived Mesenchymal Stem Cells Alleviate Hypertrophic Scar by Inhibiting Bioactivity and Inducing Apoptosis in Hypertrophic Scar Fibroblasts.

Background: As a fibrotic disease with a high incidence, the pathogenesis of hypertrophic scarring is still not fully understood, and the treatment of this disease is also challenging. In recent years, human adipose-derived mesenchymal stem cells (AD-MSCs) have been considered an effective treatment for hypertrophic scars. This study mainly explored whether the therapeutic effect of AD-MSCs on hypertrophic scars is associated with oxidative-stress-related proteins. Methods: AD-MSCs were isolated from adipose tissues and characterized through flow cytometry and a differentiation test. Afterwards, coculture, cell proliferation, apoptosis, and migration were detected. Western blotting and a quantitative real-time polymerase chain reaction (qRT-PCR) were used to detect oxidative stress-related genes and protein expression in hypertrophic scar fibroblasts (HSFs). Flow cytometry was used to detect reactive oxygen species (ROS). A nude mouse animal model was established; the effect of AD-MSCs on hypertrophic scars was observed; and hematoxylin and eosin staining, Masson's staining, and immunofluorescence staining were performed. Furthermore, the content of oxidative-stress-related proteins, including nuclear factor erythroid-2-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), B-cell lymphoma 2(Bcl2), Bcl2-associated X(BAX) and caspase 3, was detected. Results: Our results showed that AD-MSCs inhibited HSFs' proliferation and migration and promoted apoptosis. Moreover, after coculture, the expression of antioxidant enzymes, including HO-1, in HSFs decreased; the content of reactive oxygen species increased; and the expression of Nrf2 decreased significantly. In animal experiments, we found that, at 14 days after injection of AD-MSCs into human hypertrophic scar tissue blocks that were transplanted onto the dorsum of nude mice, the weight of the tissue blocks decreased significantly. Hematoxylin and eosin staining and Masson's staining demonstrated a rearrangement of collagen fibers. We also found that Nrf2 and antioxidant enzymes decreased significantly, while apoptotic cells increased after AD-MSC treatment. Conclusions: Our results demonstrated that AD-MSCs efficiently cured hypertrophic scars by promoting the apoptosis of HSFs and by inhibiting their proliferation and migration, which may be related to the inhibition of Nrf2 expression in HSFs, suggesting that AD-MSCs may provide an alternative therapeutic approach for the treatment of hypertrophic scars.

To Explore Ideas From the Altered Metabolites: The Metabolomics of Pathological Scar.

Pathological scars are dermal fibroproliferative disorders due to rapid inflammatory response after dermal injury. The altered metabolites could reflect pathophysiological changes directly. However, it has not cleared how the metabolites change scars. To explore new ideas of pathological scars from the altered metabolites by using ultra-performance liquid chromatography coupled to tandem mass spectrometry and identifying the key genes. Keloid (KS, n = 10), hypertrophic scar (HS, n = 10), and normal skin (NS, n = 10) were collected. Ultra-performance liquid chromatography coupled to tandem mass spectrometry was used to identify and characterize metabolites. Differential metabolites were analyzed by orthogonal partial least square discriminant analysis and Student t test. The key pathways were analyzed via Kyoto Encyclopedia of Genes and Genomes, and the related enzymes were verified by real-time Polymerase Chain Reaction, both in tissues and their dermal fibroblasts. Two hundred fourteen metabolites were detected in total, mostly were fatty acids and amino acids. In the KS and NS groups, 65 different metabolites were screened ( P < 0.05), and the polyunsaturated fatty acids (PUFAs) metabolism and butyric acid in keloid should be concerned. The messenger Ribonucleic Acid expression of fatty acid desaturase 1 and fatty acid desaturase 2, which are the key enzyme of PUFA metabolism, were lower in KS and keloid-derived fibroblasts, P < 0.05. In HS group, 17 metabolites were significantly different and branched chain amino acids degradation was the key pathway. Moreover, branched chain keto acid dehydrogenase E1 subunit alpha was lower expressed in HS and their fibroblasts compared with NS, P < 0.05. Polyunsaturated fatty acids and butyric acid may be associated with the generation of keloids. The pathogenesis of hypertrophic scars may be involved in branched chain amino acids degradation, which is worth paying attention to.

Alu repetitive sequence CpG methylation changes in burn scars

Alu elements are retrotransposons related to epigenetic modifications. To date, the role of epigenetics in hypertrophic scars from burn remains unknown. Here, our aim was to examine the pathophysiology of hypertrophic scars from an epigenetic perspective. For that, we performed a cross-sectional analytical study using tissue and blood samples from burned and healthy patients (n = 23 each) to detect Alu methylation levels and patterns. The results of the combined bisulfite restriction analysis technique were categorized into four groups based on the methylation status at the CpG dinucleotides from the 5′ to the 3′ ends of the Alu sequence: hypermethylated (mCmC), hypomethylated (uCuC), and partially methylated (uCmC and mCuC). Alu methylation levels were significantly lower in hypertrophic scar tissues than in normal skin (29.37 ± 2.49% vs. 35.56 ± 3.18%, p = 0.0002). In contrast, the levels were significantly higher in white blood cells from blood samples of burned patients than in those of control blood samples (26.92 ± 4.04% vs. 24.58 ± 3.34%, p = 0.0278). Alu total methylation (mC) and the uCmC pattern were significantly lower, whereas uCuC was significantly higher, in hypertrophic scar tissues than in normal skin (p < 0.0001). Receiver operating characteristic analysis indicated that the uCmC and uCuC patterns are useful as hypertrophic scar DNA methylation markers after burn, with 91.30% sensitivity and 96.23% specificity and 100% sensitivity and 94.23% specificity, respectively. Our findings suggest that epigenetic modifications play a major role in hypertrophic scar pathogenesis, and may be the starting point for developing a novel technique for burn scar treatment.

Silencing of Nesprin‐2 inhibits the differentiation of myofibroblasts from fibroblasts induced by mechanical stretch

Mechanical force plays a pivotal role in the pathogenesis of hypertrophic scar (HTS). Dermal fibroblasts and myofibroblasts are the key cells involved in HTS. Myofibroblasts in HTS possess different biochemical and biophysical characteristics by which myofibroblasts are often distinguished from fibroblasts. The role of mechanotransducers outside the nucleus in the pathogenesis of HTS has been reported in many studies. However, the role of Nesprin‐2 in HTS is not clear. Hence, we aim to construct a cell model of HTS and explore the role of Nesprin‐2 in this process. Myofibroblasts and fibroblasts were isolated from HTS and healthy skin tissues of the same patient. Fibroblasts were exposed to cyclic stretch with 10% magnitude and a frequency of 0.1 Hz for 3 days, 5 days, and 7 days, respectively. After the cell model was confirmed, fibroblasts transfected with siRNA targeting human Nesprin‐2 were exposed to cyclic stretch. The mechanical behaviour and biochemical reaction of the dermal fibroblasts were analysed. The stretched fibroblasts at day 5 showed the same mechanotransductive and biochemical features as unstretched myofibroblasts. Mechanical strain could induce the myofibroblasts differentiation and a cell model of HTS was established successfully at day 5. The expressions of lamin A/C, alpha‐smooth muscle actin, transforming growth factor beta 1, and collagen type I in fibroblasts were reduced by the silencing of Nesprin‐2. Mechanical strain could induce the myofibroblasts differentiation and silencing of Nesprin‐2 could block the mechanical stimulation of terminal myofibroblasts differentiation. Nesprin‐2 might be a potential target to treat the HTS.

MiR-124-3p targeting of TGF-β1 inhibits the proliferation of hypertrophic scar fibroblasts.

microRNAs are involved in a variety of physiological and pathophysiological processes, but their role in the pathogenesis of hypertrophic scars (HS) is not fully understood. Transforming growth factor β1 (TGF-β1) plays an important role in the genesis and development of HS. In this study, we hypothesized that a post-translational miRNA mechanism regulates the expression of TGF-β1 in HS fibroblasts (HSFBs) and participates in the development of HS. Predictions from EBCORI, PicTar and miRBase databases showed that miR-124-3p can target and regulate the expression of TGF-β1. We collected HS tissue and corresponding normal tissue from 25 patients with HS who had been operated on for the first time. The expression level of miR-124-3p in HS tissue was significantly lower than in normal tissue, while the expression level of TGF-β1 mRNA was significantly higher than in normal tissue (p < 0.05), showing a negative correlation between them. Results from a luciferase reporter assay showed that miR-124-3p targets the 3'-UTR of TGF-β1 and inhibits its expression. After miR-124-3p mimics were transfected into HSFBs, the expression of TGF-β1, α-smooth muscle actin (α-SMA), collagen I, survivin, and Bcl-2 were reduced and the expression of Bax was increased, with significant decreases in DNA synthesis, proliferation and survival. However, after a miR-124-3p inhibitor was transfected into HSFBs, these effects were reversed as the expression of TGF-β1, α-SMA, collagen I, survivin, and Bcl-2 increased, expression of Bax decreased, and DNA synthesis, proliferation and survival cells increased significantly. miR-124-3p can inhibit the proliferation of HSFBs by targeting TGF-β1, and miR-124-3p may thus be a potential therapeutic target in HS.

Establishment of a long-term hypertrophic scar model by injection of anhydrous alcohol: A rabbit model.

The processes of hypertrophic scar formation are extremely complex, and current animal models have limitations in terms of the complete characterization of lesions. An ideal animal model is indispensable for exploring the complex progression of scar formation to elucidate its pathophysiology and to perform therapeutic testing. This study aimed to establish a long-term, consistent and easily testable animal model by injecting anhydrous alcohol into the dorsal trunk dermis of rabbits. The rabbits were injected with different amounts of anhydrous alcohol. Anhydrous alcohol was infiltrated into the subcutaneous and superficial fascia. The optimal amount of anhydrous alcohol was determined by measuring the area and thickness of the scar. The typical model was established by determining the optimum dosage, and then we analysed the histological characteristics and fibrosis-associated protein expression. The dermal scar was generated by treating with 2ml/kg anhydrous alcohol and displayed histopathologic features that characterize human hypertrophic scarring, including a parallel collagen fibre orientation, dermal and epidermal thickening, broad collagen deposition and the loss of dermal adnexal structures. The expression of fibrotic pan-markers was also enhanced. Moreover, the scar features and duration were compared between the anhydrous alcohol model and the rabbit ear model. Our results show that injecting anhydrous alcohol in the rabbit model thickened the dermal tissue, stimulated dermal fibroproliferation and resulted in hypertrophic scars with protein and histologic features similar to those seen in humans. Taken together, the findings from this study show that our model could be a feasible and useful tool for further research on the pathogenesis of hypertrophic scars.

Overexpression of miR-101 suppresses collagen synthesis by targeting EZH2 in hypertrophic scar fibroblasts.

BackgroundMicroRNA-101 (miR-101) is a tumor suppressor microRNA (miRNA) and its loss is associated with the occurrence and progression of various diseases. However, the biological function and target of miR-101 in the pathogenesis of hypertrophic scars (HS) remains unknown.MethodsWe harvested HS and paired normal skin (NS) tissue samples from patients and cultured their fibroblasts (HSF and NSF, respectively). We used quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), fluorescence in situ hybridization (FISH), enzyme-linked immunosorbent assays (ELISA) and Western blot analyses to measure mRNA levels and protein expression of miR-101, enhancer of zeste homolog 2 (EZH2), collagen 1 and 3 (Col1 and Col3) and α-smooth muscle actin (α-SMA) in different in vitro conditions. We also used RNA sequencing to evaluate the relevant signaling pathways and bioinformatics analysis and dual-luciferase reporter assays to predict miR-101 targets. We utilized a bleomycin-induced fibrosis mouse model in which we injected miR-101 mimics to evaluate collagen deposition in vivo.ResultsWe found low expression of miR-101 in HS and HSF compared to NS and NSF. Overexpressing miR-101 decreased Col1, Col3 and α-SMA expression in HSF. We detected high expression of EZH2 in HS and HSF. Knockdown of EZH2 decreased Col1, Col3 and α-SMA in HSF. Mechanistically, miR-101 targeted the 3′-untranslated region (3′UTR) of EZH2, as indicated by the decreased expression of EZH2. Overexpressing EZH2 rescued miR-101-induced collagen repression. MiR-101 mimics effectively suppressed collagen deposition in the bleomycin-induced fibrosis mouse model.ConclusionsOur data reveal that miR-101 targets EZH2 in HS collagen production, providing new insight into the pathological mechanisms underlying HS formation.

Tissue Expression of Neuregulin-1 in Hypertrophic Scars and Keloids before and after Intralesional Bleomycin Injection

Hypertrophic scars and keloids are forms of abnormal wound healing. Both entities are the result of exuberant fibroblast response in the dermis. Nevertheless, their clinical and histopathological characteristics, as well as their pathogenesis, are differentThe aim of this study was to study the role of neuregulin- 1 in the pathogenesis of hypertrophic scars and keloids and studying the change in tissue expression after intralesional bleomycin injection. This prospective case - control study was carried on20patients who were suffering from keloids or hypertrophic scarsand were treated by intra lesional bleomycin injection, in addition to 20 apparently healthy individuals as a control group. Assement of hypertrophic scars and keloids before and after treatment byVancouver scar scale laboratory investigations including punch biopsies from hypertrophic scars, keloids and normal tissues, qRT-PCRfor gene expression of Neuregulin1 RNA was done. HTS group before treatment showed significantly higher level of neuregulin 1 but significantly lower after treatment and neuregulin 1 sensitivity was 80%, specificity was 100%,and accuracy was 90%.Neuregulin 1 before treatment showed significant positive correlation with Neuregulin 1after treatment.Better response was significantly associated with Lower baseline neuregulin 1.Higher neuregulin 1 was considered as risk predictor of HTS or keloid susceptibility and severity. Bleomycin usage has a better result and minimal complications and less recurrence rate, which shows its usefulness as the first-line treatment modality for management of keloids and hypertrophic scars.

LINC00173 promotes the apoptosis of hypertrophic scar fibroblasts through increasing β-catenin expression.

Previous studies have demonstrated the involvement of long intergenic nonprotein coding RNA 173 (LINC00173) in several pathological disorders. However, the function of LINC00173 in the hypertrophic scar is not well understood. This study confirmed that the two transcript variants of TSV1 and TSV2 were both upregulated in hypertrophic scar fibroblasts. The overexpression of TSV1 or TSV2 promoted the apoptosis of fibroblasts, whereas the overexpression of TSV2 inhibited the proliferation of fibroblasts. RNA-sequencing (RNA-seq), Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis, and gene set enrichment analysis (GSEA) showed that phosphatidylinositol 3-kinase (PI3K)/Akt and Mitogen-activated protein kinases (MAPK) signaling might be involved in the role of LINC00173 in hypertrophic scar pathogenesis. Furthermore, the protein expression of β-catenin was upregulated in the TSV1 or TSV2 overexpression group. Overall, the study demonstrated that LINC00173 promoted the apoptosis of fibroblasts through increasing β-catenin expression, suggesting that LINC00173 might be a new target for hypertrophic scar treatment.

Inhibition of Notch Intracellular Domain Suppresses Cell Activation and Fibrotic Factors Production in Hypertrophic Scar Fibroblasts Versus Normal Skin Fibroblasts.

Hypertrophic scar (HS) is the most common complication after skin injury with unknown etiopathogenesis. There is increasing evidence to suggest that aberrant Notch signaling contributes directly to skin pathogenesis and altered expression of the Notch intracellular domain (NICD) identified in HS. Therefore, the aim of this study was to investigate the effects of Notch signaling pathway in HS pathogenesis. Hypertrophic scar and normal skin samples were collected. Notch intracellular domain expression was detected by immunohistochemistry staining and fibroblasts were separated from the samples. We compared fibrotic factors production, cell viability, migration and apoptosis of HS fibroblasts (HFB) versus normal skin fibroblasts (NFB) by real time quantitative polymerase chain reaction, MTS, cell scratch assay and flow cytometry respectively under the impact of inhibition of Notch signaling by NICD-small-interfering RNA (SiRNA). The results showed that NICD was overexpressed in the dermis of HS tissues. Inhibition of Notch signaling by NICD-SiRNA suppressed the production of the fibrotic factors including collagen 1, collagen 3, α-SMA, and TGF-β1 by HFB and NFB. Cell viability and migration were reduced in NICD-SiRNA-treated NFB and HFB, whereas cell apoptosis was enhanced by NICD-SiRNA. Conclusively, the study demonstrates a potential role for Notch signaling in HS progression, and targeting this pathway may provide a novel strategy for treatment of HS.

Lower Metal Element Levels in Hypertrophic Scars: A Potential Mechanism of Aberrant Cicatrix Hyperplasia.

BackgroundWe investigated levels of the metal elements Ca, Mg, Zn, Fe, and Cu in blood, normal skin (NS), and different types of scar tissue and aimed to elucidate the pathogenesis of hypertrophic scars (HS).Material/MethodsTissue specimens were excised from 3 groups of research participants: scar-free, flat scar (FS), and HS groups. Levels of the study elements were measured in blood, NS, and scar tissues with a spectrophotometer. The levels in plasma or in different types of specimens were compared among subgroups. In the FS and HS groups, levels were compared between the scar tissue and NS of each individual. In addition, element differences in exposed and unexposed areas of NS were investigated in the scar-free group. HS fibroblasts (HFB) were cultured in medium with various reduced levels of metal elements to determine the influence of metal elements on fibroblast growth.ResultsLevels of trace elements, including Zn, Fe, and Cu, were significantly lower in HS than in FS. The levels of Ca, Zn, Fe, and Cu were markedly lower in HS than in the patients’ own NS, while the Cu/Zn ratio was higher. However, no such difference was observed in the FS group. No significant difference in element levels was found in either plasma or NS among the 3 groups. Reduced levels of the elements promoted HFB proliferation within 24 h while an inhibition effect was observed at 72 h.ConclusionsOur findings indicate reduced levels of metal elements in part of the healing microenvironment, suggesting that decreased metal levels may be involved in the pathogenesis of HS.

MiR-495 inhibits the growth of fibroblasts in hypertrophic scars.

Noncoding RNAs are known to be importantly involved in a variety physiological and pathophysiolgical processes. Their role in the pathogenesis of hypertrophic scars remains unclear, however. After preliminary screening of the microRNA (miRNA) gene expression profiles, we explored the role of miR-495 in the development of hypertrophic scar by comparing expression of miR-495 and focal adhesion kinase (FAK) between hypertrophic scar and normal skin tissue. We also used 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and annexin V-fluorescein isothiocyanate/propidium iodide assays to assess the effect of miR-495 on the proliferation and apoptosis in human hypertrophic scar fibroblasts. Western blotting and real-time polymerase chain reaction were used to evaluate expression of miR-495, FAK, and related proteins in the FAK pathway. Our findings show that miR-495 inhibits FAK and its downstream mediators in vitro and vivo, and suggest that miR-495 may be a useful therapeutic target for the treatment of hypertrophic scar.

MiR-181b-5p promotes proliferation and inhibits apoptosis of hypertrophic scar fibroblasts through regulating the MEK/ERK/p21 pathway.

Hypertrophic scar (HS) is a common skin disorder occurring during the wound healing process, and the pathogenesis of HS remains unclear. Previous studies indicated that miRNAs may be involved in the onset and progression of HS. In the present study, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were used to investigate the expression of miR-181b-5p and decorin in HS tissues. Direct interaction between miR-181b-5p and decorin was confirmed using a dual-luciferase assay. Human HS fibroblasts (HSFbs) were cultured and transfected with miR-181b-5p mimics, and MTT assay and Annexin V fluorescein isothiocyanate/propidium iodide staining were performed to investigate the role of miR-181b-5p in the proliferation and apoptosis of HSFbs. Subsequently, the expression levels of mitogen-activated protein kinase kinase (MEK), phospho (p)-extracellular signal-regulated kinase (ERK) and p21 were determined in HSFbs transfected with miR-181b-5p mimics and untransfected cells using RT-qPCR and western blotting. The results indicated upregulation of miR-181b-5p and downregulation of decorin expression in HS tissues compared with normal skin samples. miR-181b-5p may regulate the expression of decorin through direct binding to the 3′-untranslated region, as demonstrated by the results of the dual-luciferase assay. Transfection with miR-181b-5p mimics in HSFbs enhanced cell proliferation, reduced apoptosis and increased the expression of MEK, p-ERK and p21. Furthermore, treatment with MEK inhibitor in HSFbs transfected with miR-181b-5p mimics partially inhibited miR-181b-5p-induced antiapoptotic effects. Taken together, increased expression of miR-181b-5p may serve important roles in the pathogenesis of HS through regulating the MEK/ERK/p21 pathway, suggesting that miR-181b-5p may be a therapeutic target for the treatment of HS.

The clinical dynamic changes of macrophage phenotype and function in different stages of human wound healing and hypertrophic scar formation.

The pathogenesis of hypertrophic scar (HS) is still poorly understood. Macrophages, especially the polarisation of that to M1 or M2, play a pivotal role in control of the degree of scar formation. Profiling of macrophage phenotypes in human specimens during long-term period of wound healing and HS formation may provide valuable clinical evidence for understanding the pathology of human scars. Human wound and HS specimens were collected, the macrophage phenotype was identified by immunofluorescence, and biomarkers and cytokines associated with M1 and M2 macrophages were detected by RT-PCR. The correlation between the macrophage phenotype and HS characteristics was analysed by linear regression analyses. We found excessive and persistent infiltration by M1 macrophages around the blood vessels in the superficial layer of the dermis at early wound tissues, whereas M2 macrophages predominated in later wound tissues and the proliferative phase of HS and were scattered throughout the dermis. The density of M1 macrophages was positively correlated with mRNA expression levels of tumour necrosis factor-alpha (TNF-α) and IL-6. The density of M2 macrophages was positively correlated with ARG1 and negatively correlated with the duration of HS. The sequential infiltration by M1 macrophage and M2 macrophages in human wound and HS tissues was confirmed.