Mechanisms underlying pathological scarring by fibroblasts during wound healing

Development and characterization of a novel immortalized human vaginal fibroblast cell line for advanced applications in reproductive health

BACKGROUND

Reproductive health issues related to the vagina, face significant challenges due to the lack of standardized research models. Vaginal fibroblasts, which constitute approximately 55% of the vaginal wall's cellular composition, are crucial for tissue repair, remodelling, and reproductive health. These fibroblasts have broad applications in regenerative medicine and gynaecological treatments. Despite their importance, current research relies primarily on epithelial cells or primary vaginal fibroblasts, but primary fibroblasts are limited by their short lifespan, donor-to-donor variability, and susceptibility to senescence. Immortalized fibroblast lines offer a solution by extending the lifespan and enabling reproducible studies. However, a well-characterized immortalized human vaginal fibroblast line has not been established, highlighting the need for novel models to better understand and address vaginal-associated conditions.

METHODS

Primary human vaginal fibroblasts were immortalized via the lentiviral transfection of human telomerase reverse transcriptase. The resulting cell line was characterized through histological, immunofluorescent, RT-qPCR and flow cytometry analyses. Proliferation, senescence, gene expression, hormone responsiveness and genomic stability were assessed via quantitative polymerase chain reaction, transcriptome sequencing, gene set enrichment analysis, short tandem repeat profiling, and karyotype analysis.

RESULTS

The immortalized human vaginal fibroblasts (ihVFs) retained typical spindle-shaped fibroblast morphology and fibroblast-specific marker expression. Compared with primary vaginal fibroblasts, ihVF exhibited significantly reduced senescence, maintained sustained growth through extended culture passages, and preserved genetic stability. Transcriptome sequencing revealed high gene expression similarity between immortalized and primary fibroblasts, with no significant alterations in oncogenic pathways. PCR and immunofluorescent analyses revealed that ihVFs are responsive to estrogen and progesterone stimulation. Short tandem repeat analysis confirmed the novelty of the immortalized cell line, with no overlap with existing cell databases.

CONCLUSIONS

The novel ihVF cell line retains key phenotypic, functional, and genetic characteristics of primary vaginal fibroblasts, providing a stable, reproducible, and physiologically relevant model for reproductive health research. This cell line addresses the limitations of primary fibroblasts and has broad applications in tissue engineering, gynaecological disorder research, and drug screening, advancing our understanding of vaginal fibroblast biology and therapeutic interventions.

Mesenchymal stem cells and their exosomes: a novel approach to skin regeneration via signaling pathways activation

Accelerating wound healing is a crucial objective in surgical and regenerative medicine. The wound healing process involves three key stages: inflammation, cell proliferation, and tissue repair. Mesenchymal stem cells (MSCs) have demonstrated significant therapeutic potential in promoting tissue regeneration, particularly by enhancing epidermal cell migration and proliferation. However, the precise molecular mechanisms underlying MSC-mediated wound healing remain unclear. This review highlights the pivotal role of MSCs and their exosomes in wound repair, with a specific focus on critical signaling pathways, including PI3K/Akt, WNT/β-catenin, Notch, and MAPK. These pathways regulate essential cellular processes such as proliferation, differentiation, and angiogenesis. Moreover, in vitro and in vivo studies reveal that MSCs accelerate wound closure, enhance collagen deposition, and modulate immune responses, contributing to improved tissue regeneration. Understanding these mechanisms provides valuable insights into MSC-based therapeutic strategies for enhancing wound healing.

Single-nucleus transcriptome profiling provides insights into the pathophysiology of adhesive arachnoiditis

Adhesive arachnoiditis (AA) is a rare form of chronic degenerative pathology associated with persistent inflammation in the arachnoid matter of the spinal cord. Despite the existing knowledge, the detailed pathological mechanisms underlying AA are not fully understood. This study aimed to elucidate through comprehensive single nuclei RNA sequencing (snRNA-seq) to delineate the transcriptomic landscape of AA. From six arachnoid membrane samples, a total of 52,886 cells met the quality control standards for analysis. The main cell populations identified with specific gene markers were as follows: fibroblasts, glial cells, microglial cells, endothelial cells, mural cells, plasma cells, and T cells. Downstream analysis of fibroblasts, glial cells, and microglial cells was performed. Notably, fibroblast subsets 1 and 3 demonstrated a strong association with AA. Among them, subcluster 3 demonstrated elevated expression of genes COL1A1, COL3A1, and FN1, indicative of enhanced Wnt/β-catenin and extracellular matrix (ECM) synthesis pathways. Subcluster 3 was predicted to progressively transform into subcluster 1. In subcluster 1, there was a significant upregulation of genes such as BMP and ALPL, signaling enhanced activation of calcification-related pathways. This was highly relevant to end-stage arachnoid ossification formation. After being activated, microglial cells transformed into inflammatory disease-associated microglial cells and continued to express high levels of chemokines CCL2, CCL4, IL-1β, and other inflammatory factors NAMPT, INPP5D and NLRP3. This might be the main reason why AA recurrence is frequently observed in patients. These insights enhance our understanding of the pathological progression of AA and may contribute to the identification of novel therapeutic targets.

Interplay between genetics and epigenetics in lung fibrosis

Lung fibrosis, including idiopathic pulmonary fibrosis (IPF), is a complex and devastating disease characterised by the progressive scarring of lung tissue leading to compromised respiratory function. Aberrantly activated fibroblasts deposit extracellular matrix components into the surrounding lung tissue, impairing lung function and capacity for gas exchange. Both genetic and epigenetic factors have been found to play a role in the pathogenesis of lung fibrosis, with emerging evidence highlighting the interplay between these two regulatory mechanisms. This review provides an overview of the current understanding of the interplay between genetics and epigenetics in lung fibrosis. We discuss the genetic variants associated with susceptibility to lung fibrosis and explore how epigenetic modifications such as DNA methylation, histone modifications, and non-coding RNA expression contribute to disease. Insights from genome-wide association studies (GWAS) and epigenome-wide association studies (EWAS) are integrated to explore the molecular mechanisms underlying lung fibrosis pathogenesis. We also discuss the potential clinical implications of genetics and epigenetics in lung fibrosis, including the development of novel therapeutic targets. Overall, this review highlights the importance of considering both genetic and epigenetic factors in the understanding and management of lung fibrosis.

Multifunctional Bioactive Nanozyme Systems for Enhanced Diabetic Wound Healing

The protracted transition from inflammation to proliferation in diabetic wound healing poses significant challenges, exacerbated by persistent inflammatory responses and inadequate vascularization. To address these issues, a novel nanozymatic therapeutic approach utilizing asymmetrically structured MnO₂-Au-mSiO₂@aFGF Janus nanoparticles is engineered. Nanozymes featuring a mSiO₂ head and MnO₂ extensions, into which acidic fibroblast growth factor (aFGF) is encapsulated, resulting in MnO₂-Au-mSiO₂@aFGF Janus nanoparticles (mSAM@aFGF), are synthesized. This nanozyme system effectively emulates enzymatic activities of catalase (CAT) and superoxide dismutase (SOD), catalyzing degradation of reactive oxygen species (ROS) and generating oxygen. In addition, controlled release of aFGF fosters tissue regeneration and vascularization. In vitro studies demonstrate that mSAM@aFGF significantly alleviates oxidative stress in cells, and enhances cell proliferation, migration, and angiogenesis. An injectable hydrogel based on photocrosslinked hyaluronic acid (HAMA), incorporating the nanozymatic ROS-scavenging and growth factor-releasing system, is developed. The HAMA-mSAM@aFGF hydrogel exhibits multifaceted benefits in a diabetic wound model, including injectability, wound adhesion, hemostasis, anti-inflammatory effects, macrophage polarization from M1 to M2 phenotype, and promotion of vascularization. These attributes underscore the potential of this system to facilitate transition from chronic inflammation to the proliferative phase of wound repair, offering a promising therapeutic strategy for diabetic wound management.

Emerging biomedical technologies for scarless wound healing

Complete wound healing without scar formation has attracted increasing attention, prompting the development of various strategies to address this challenge. In clinical settings, there is a growing preference for emerging biomedical technologies that effectively manage fibrosis following skin injury, as they provide high efficacy, cost-effectiveness, and minimal side effects compared to invasive and costly surgical techniques. This review gives an overview of the latest developments in advanced biomedical technologies for scarless wound management. We first introduce the wound healing process and key mechanisms involved in scar formation. Subsequently, we explore common strategies for wound treatment, including their fabrication methods, superior performance and the latest research developments in this field. We then shift our focus to emerging biomedical technologies for scarless wound healing, detailing the mechanism of action, unique properties, and advanced practical applications of various biomedical technology-based therapies, such as cell therapy, drug therapy, biomaterial therapy, and synergistic therapy. Finally, we critically assess the shortcomings and potential applications of these biomedical technologies and therapeutic methods in the realm of scar treatment.

Exosomal miR‑194 from adipose‑derived stem cells impedes hypertrophic scar formation through targeting TGF‑β1

Hypertrophic scars, which result from aberrant fibrosis and disorganized collagen synthesis by skin fibroblasts, emerge due to disrupted wound healing processes. These scars present significant psychosocial and functional challenges to affected individuals. The current treatment limitations largely arise from an incomplete understanding of the underlying mechanisms of hypertrophic scar development. Recent studies, however, have shed light on the potential of exosomal non‑coding RNAs interventions to mitigate hypertrophic scar proliferation. The present study assessed the impact of exosomes derived from adipose‑derived stem cells (ADSCs‑Exos) on hypertrophic scar formation using a rabbit ear model. It employed hematoxylin and eosin staining, Masson's trichrome staining and immunohistochemical staining techniques to track scar progression. The comprehensive analysis of the present study encompassed the differential expression of non‑coding RNAs, enrichment analyses of functional pathways, protein‑protein interaction studies and micro (mi)RNA‑mRNA interaction investigations. The results revealed a marked alteration in the expression levels of long non‑coding RNAs and miRNAs following ADSCs‑Exos treatment, with little changes observed in circular RNAs. Notably, miRNA (miR)‑194 emerged as a critical regulator within the signaling pathways that govern hypertrophic scar formation. Dual‑luciferase assays indicated a significant reduction in the promoter activity of TGF‑β1 following miR‑194 overexpression. Reverse transcription‑quantitative PCR and immunoblotting assays further validated the decrease in TGF‑β1 expression in the treated samples. In addition, the treatment resulted in diminished levels of inflammatory markers IL‑1β, TNF‑α and IL‑10. In vivo evidence strongly supported the role of miR‑194 in attenuating hypertrophic scar formation through the suppression of TGF‑β1. The present study endorsed the strategic use of ADSCs‑Exos, particularly through miR‑194 modulation, as an effective strategy for reducing scar formation and lowering pro‑inflammatory and fibrotic indicators such as TGF‑β1. Therefore, the present study advocated the targeted application of ADSCs‑Exos, with an emphasis on miR‑194 modulation, as a promising approach to managing proliferative scarring.

Hydrogen sulfide regulates macrophage polarization and necroptosis to accelerate diabetic skin wound healing

Hydrogen sulfide (H2S), recognized as the third gasotransmitter, plays a pivotal role in the pathophysiological processes of various diseases. Cystathionine γ-lyase (CSE) is the main enzyme for H2S production in the skin. However, effects and mechanisms of H2S in diabetic skin wound healing remain unclear. Our findings revealed a decrease in plasma H2S content in diabetic patients with skin wounds. CSE knockout (KO) diabetic mice resulted in delayed wound healing, reduced blood perfusion, and CD31 expression around the wounds. It also led to increased infiltration of inflammatory cells and M1-type macrophages, decreased collagen levels, α-smooth muscle actin (α-SMA), and proliferating cell nuclear antigen (PCNA) expression. Additionally, there were enhanced expressions of necroptosis related proteins, including receptor interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain like protein (MLKL). In comparison, sodium hydrosulfide (NaHS), H2S donor, accelerated skin wound healing in leptin receptor deficiency (db/db) mice. This acceleration was accompanied by increased blood perfusion and CD31 expression, reduced infiltration of inflammatory cells and M1-type macrophages, elevated collagen levels, α-SMA, and PCNA expressions, and decreased necroptosis-related protein expressions together with nuclear factor-κB (NF-κB) p65 phosphorylation. In conclusion, H2S regulates macrophage polarization and necroptosis, contributing to the acceleration of diabetic skin wound healing. These findings offer a novel strategy for the treatment of diabetic skin wounds.

AESIS-1, a Rheumatoid Arthritis Therapeutic Peptide, Accelerates Wound Healing by Promoting Fibroblast Migration in a CXCR2-Dependent Manner

In patients with autoimmune disorders such as rheumatoid arthritis (RA), delayed wound healing is often observed. Timely and effective wound healing is a crucial determinant of a patient's quality of life, and novel materials for skin wound repair, such as bioactive peptides, are continuously being studied and developed. One such bioactive peptide, AESIS-1, has been studied for its well-established anti-rheumatoid arthritis properties. In this study, we attempted to use the anti-RA material AESIS-1 as a therapeutic wound-healing agent based on disease-modifying antirheumatic drugs (DMARDs), which can help restore prompt wound healing. The efficacy of AESIS-1 in wound healing was assessed using a full-thickness excision model in diabetic mice; this is a well-established model for studying chronic wound repair. Initial observations revealed that mice treated with AESIS-1 exhibited significantly advanced wound repair compared with the control group. In vitro studies revealed that AESIS-1 increased the migration activity of human dermal fibroblasts (HDFs) without affecting proliferative activity. Moreover, increased HDF cell migration is mediated by upregulating chemokine receptor expression, such as that of CXC chemokine receptor 2 (CXCR2). The upregulation of CXCR2 through AESIS-1 treatment enhanced the chemotactic reactivity to CXCR2 ligands, including CXC motif ligand 8 (CXCL8). AESIS-1 directly activates the ERK and p38 mitogen-activated protein kinase (MAPK) signaling cascades, which regulate the migration and expression of CXCR2 in fibroblasts. Our results suggest that the AESIS-1 peptide is a strong wound-healing substance that increases the movement of fibroblasts and the expression of CXCR2 by turning on the ERK and p38 MAPK signaling cascades.

Endogenous stimuli-responsive separating microneedles to inhibit hypertrophic scar through remodeling the pathological microenvironment

Hypertrophic scar (HS) considerably affects the appearance and causes tissue dysfunction in patients. The low bioavailability of 5-fluorouracil poses a challenge for HS treatment. Here we show a separating microneedle (MN) consisting of photo-crosslinked GelMA and 5-FuA-Pep-MA prodrug in response to high reactive oxygen species (ROS) levels and overexpression of matrix metalloproteinases (MMPs) in the HS pathological microenvironment. In vivo experiments in female mice demonstrate that the retention of MN tips in the tissue provides a slowly sustained drug release manner. Importantly, drug-loaded MNs could remodel the pathological microenvironment of female rabbit ear HS tissues by ROS scavenging and MMPs consumption. Bulk and single cell RNA sequencing analyses confirm that drug-loaded MNs could reverse skin fibrosis through down-regulation of BCL-2-associated death promoter (BAD), insulin-like growth factor 1 receptor (IGF1R) pathways, simultaneously regulate inflammatory response and keratinocyte differentiation via up-regulation of toll-like receptors (TOLL), interleukin-1 receptor (IL1R) and keratinocyte pathways, and promote the interactions between fibroblasts and keratinocytes via ligand-receptor pair of proteoglycans 2 (HSPG2)-dystroglycan 1(DAG1). This study reveals the potential therapeutic mechanism of drug-loaded MNs in HS treatment and presents a broad prospect for clinical application.

Insights into the unique roles of dermal white adipose tissue (dWAT) in wound healing

Dermal white adipose tissue (dWAT) is a newly recognized layer of adipocytes within the reticular dermis of the skin. In many mammals, this layer is clearly separated by panniculus carnosus from subcutaneous adipose tissue (sWAT). While, they concentrated around the hair shaft and follicle, sebaceous gland, and arrector pili muscle, and forms a very specific cone geometry in human. Both the anatomy and the histology indicate that dWAT has distinct development and functions. Different from sWAT, the developmental origin of dWAT shares a common precursor with dermal fibroblasts during embryogenesis. Therefore, when skin injury happens and mature adipocytes in dWAT are exposed, they may undergo lipolysis and dedifferentiate into fibroblasts to participate in wound healing as embryogenetic stage. Studies using genetic strategies to selectively ablate dermal adipocytes observed delayed revascularization and re-epithelialization in wound healing. This review specifically summarizes the hypotheses of the functions of dWAT in wound healing. First, lipolysis of dermal adipocytes could contribute to wound healing by regulating inflammatory macrophage infiltration. Second, loss of dermal adipocytes occurs at the wound edge, and adipocyte-derived cells then become ECM-producing wound bed myofibroblasts during the proliferative phase of repair. Third, mature dermal adipocytes are rich resources for adipokines and cytokines and could release them in response to injury. In addition, the dedifferentiated dermal adipocytes are more sensitive to redifferentiation protocol and could undergo expansion in infected wound. We then briefly introduce the roles of dWAT in protecting the skin from environmental challenges: production of an antimicrobial peptide against infection. In the future, we believe there may be great potential for research in these areas: (1) taking advantage of the plasticity of dermal adipocytes and manipulating them in wound healing; (2) investigating the precise mechanism of dWAT expansion in infected wound healing.