RNA-seq-based analysis of the hypertrophic scarring with and without pressure therapy in a Bama minipig model

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.

Traditional Chinese medicine for hypertrophic scars—A review of the therapeutic methods and potential effects

Hypertrophic scar (HS) is a typical pathological response during skin injury, which can lead to pain, itching, and contracture in patients and even affect their physical and mental health. The complexity of the wound healing process leads to the formation of HS affected by many factors. Several treatments are available for HS, whereas some have more adverse reactions and can even cause new injuries with exacerbated scarring. Traditional Chinese Medicine (TCM) has a rich source, and most botanical drugs have few side effects, providing new ideas and methods for treating HS. This paper reviews the formation process of HS, the therapeutic strategy for HS, the research progress of TCM with its relevant mechanisms in the treatment of HS, and the related new drug delivery system of TCM, aiming to provide ideas for further research of botanical compounds in the treatment of HS, to promote the discovery of more efficient botanical candidates for the clinical treatment of HS, to accelerate the development of the new drug delivery system and the final clinical application, and at the same time, to promote the research on the anti-HS mechanism of multiherbal preparations (Fufang), to continuously improve the quality control and safety and effectiveness of anti-HS botanical drugs in clinical application.

A Systematic Review Comparing Animal and Human Scarring Models

Introduction

A reproducible, standardised model for cutaneous scar tissue to assess therapeutics is crucial to the progress of the field. A systematic review was performed to critically evaluate scarring models in both animal and human research.

Method

All studies in which cutaneous scars are modelling in animals or humans were included. Models that were focused on the wound healing process or those in humans with scars from an existing injury were excluded. Ovid Medline^® was searched on 25 February 2019 to perform two near identical searches; one aimed at animals and the other aimed at humans. Two reviewers independently screened the titles and abstracts for study selection. Full texts of potentially suitable studies were then obtained for analysis.

Results

The animal kingdom search yielded 818 results, of which 71 were included in the review. Animals utilised included rabbits, mice, pigs, dogs and primates. Methods used for creating scar tissue included sharp excision, dermatome injury, thermal injury and injection of fibrotic substances. The search for scar assessment in humans yielded 287 results, of which 9 met the inclusion criteria. In all human studies, sharp incision was used to create scar tissue. Some studies focused on patients before or after elective surgery, including bilateral breast reduction, knee replacement or midline sternotomy.

Discussion

The rabbit ear scar model was the most popular tool for scar research, although pigs produce scar tissue which most closely resembles that of humans. Immunodeficient mouse models allow for in vivo engraftment and study of human scar tissue, however, there are limitations relating to the systemic response to these xenografts. Factors that determine the use of animals include cost of housing requirements, genetic traceability, and ethical concerns. In humans, surgical patients are often studied for scarring responses and outcomes, but reproducibility and patient factors that impact healing can limit interpretation. Human tissue use in vitro may serve as a good basis to rapidly screen and assess treatments prior to clinical use, with the advantage of reduced cost and setup requirements.

miR-211-5p inhibits the proliferation, migration, invasion, and induces apoptosis of human hypertrophic scar fibroblasts by regulating TGFβR2 expression

Background

Hypertrophic-scar (HS) is the most common pathological healing phenomenon after trauma, especially after deep burns. We aimed to investigate the expression and role of microRNA-211-5p (miR-211-5p) in HS and explore its underlying mechanism.

Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect the expression of miR-211-5p in 15 cases of HS tissues and normal skin tissues, as well as its expression in human hypertrophic scar fibroblasts (hHSFs) and normal fibroblasts. At the same time, the cell counting kit-8 (CCK-8), scratch test, cell invasion test, and flow cytometry were used to determine cell proliferation, migration, invasion, and apoptosis, respectively. Western blot assay was used to determine the expression of proteins. TargetScan was performed to predict the potential binding sites between miR-211-5p and TGFβR2, which was then verified by western blotting and luciferase reporter gene experiments. Also, co-transfection of plasmids that overexpress miR-211-5p and TGFβR2 were used to observe the reversal effect of miR-211-5p.

Results

The level of miR-211-5p in HS tissues and hHSFs cells was significantly down-regulated (both P<0.05). The TGFβR2/Smad3 signaling pathway was activated (both P<0.05). Furthermore, the overexpression of miR-211-5p could inhibit the proliferation (P<0.05), migration (P<0.05), and invasion (P<0.05) of hHSFs cells, and induce their apoptosis (P<0.05), and could also regulate the expression of related proteins (all P<0.05). Moreover, the overexpression of miR-211-5p could also inhibit the accumulation of ECM and the activation of the TGF-βR2/Smad3 pathway (all P<0.05), while the opposite effect (all P<0.05) was observed when the level of miR-211-5p was interfered with. Finally, it was confirmed that miR-211-5p could target TGFβR2 (all P<0.05), and when hHSFs cells simultaneously overexpressed miR-211-5p and TGFβR2, the promotion effect of TGFβR2 on cells was reversed by miR-211-5p (all P<0.05).

Conclusions

miR-211-5p can inhibit the activation of the TGF-βR2/Smad3 signaling pathway by targeting TGFβR2, thereby suppressing the proliferation, migration, invasion, and ECM production of hHSFs, and inducing their apoptosis, suggesting that miR-211-5p can become a potential target for the treatment of HS.

Mammalian Annotation Database for improved annotation and functional classification of Omics datasets from less well-annotated organisms

Next-generation sequencing technologies and the availability of an increasing number of mammalian and other genomes allow gene expression studies, particularly RNA sequencing, in many non-model organisms. However, incomplete genome annotation and assignments of genes to functional annotation databases can lead to a substantial loss of information in downstream data analysis. To overcome this, we developed Mammalian Annotation Database tool (MAdb, https://madb.ethz.ch) to conveniently provide homologous gene information for selected mammalian species. The assignment between species is performed in three steps: (i) matching official gene symbols, (ii) using ortholog information contained in Ensembl Compara and (iii) pairwise BLAST comparisons of all transcripts. In addition, we developed a new tool (AnnOverlappeR) for the reliable assignment of the National Center for Biotechnology Information (NCBI) and Ensembl gene IDs. The gene lists translated to gene IDs of well-annotated species such as a human can be used for improved functional annotation with relevant tools based on Gene Ontology and molecular pathway information. We tested the MAdb on a published RNA-seq data set for the pig and showed clearly improved overrepresentation analysis results based on the assigned human homologous gene identifiers. Using the MAdb revealed a similar list of human homologous genes and functional annotation results regardless of whether starting with gene IDs from NCBI or Ensembl. The MAdb database is accessible via a web interface and a Galaxy application.

Transcriptional Differences of Coding and Non-Coding Genes Related to the Absence of Melanocyte in Skins of Bama Pig

Skin is the body’s largest organ, and the main function of skin is to protect underlying organs from possible external damage. Melanocytes play an important role in skin pigmentation. The Bama pig has a “two-end-black” phenotype with different coat colors across skin regions, e.g., white skin (without melanocytes) and black skin (with melanocytes), which could be a model to investigate skin-related disorders, specifically loss of melanocytes. Here, we generated expression profiles of mRNAs and long noncoding RNAs in Bama pig skins with different coat colors. In total, 14,900 mRNAs and 7549 lncRNAs were expressed. Overall, 2338 mRNAs/113 lncRNAs with FDR-adjusted p-value ≤ 0.05 were considered to be differentially expressed (DE) mRNAs/lncRNAs, with 1305 down-regulated mRNAs and 1033 up-regulated mRNAs in white skin with|log₂(fold change)| > 1. The genes down-regulated in white skin were associated with pigmentation, melanocyte–keratinocyte interaction, and keratin, while up-regulated ones were mainly associated with cellular energy metabolisms. Furthermore, those DE lncRNAs were predicted to be implicated in pigmentation, keratin synthesis and cellular energy metabolism. In general, this study provides insight into the transcriptional difference involved in melanocyte-loss-induced keratinocyte changes and promotes the Bama pig as a biomedical model in skin research.