Dermal fibroblasts—A heterogeneous population with regulatory function in wound healing

Cytotoxicity evaluation of microbial sophorolipids and glucolipids using normal human dermal fibroblasts (NHDF) in vitro

Fibroblasts are considered a key player in the wound healing process. Although this cellular family is constituted by several distinct subtypes, dermal fibroblasts are crucial thanks to their ability to secrete pro-regenerative growth factors, extracellular matrix (ECM) proteins and their immune and anti-inflammatory role. Sophorolipids (SL), sophorosides (SS) and glucolipids (G), mono-unsaturated (C18:1) or saturated (C18:0), glycolipids derived from microbial fermentation of wild type or engineered yeast Starmerella bombicola, constitute a novel sustainable class of bio-based chemicals with interesting physicochemical characteristics, which allow them to form soft diverse structures from hydrogels to vesicles, micelles or complex coacervates with potential interest in skin regeneration applications. In this study, we first tested the cytocompatibility of a broad set of molecules from this family on normal human dermal fibroblasts (NHDF). Our results show that, up to an upper threshold (0.1 % w/v), the microbial glycolipids (SL-C18:1, G-C18:1, SSbola-C18:1, SL-C18:0 and G-C18:0) under study were able to sustain cell growth. Furthermore, we selected the least cytotoxic glycolipids (SL-C18:1, SSbola-C18:1, SL-C18:0) to study their potential to promote wound healing by measuring the gene expression of several key skin regeneration markers (i.e. collagen, elastin, transforming growth factor β, fibroblast growth factor …) using qPCR. Unfortunately, none of these glycolipids modulated the gene expression of molecules involved in tissue repair. However, this study aims to encourage the community to test this novel class of molecules for novel high-end biomedical applications.

Importance

Biosurfactants prepared by microbial fermentation are natural amphiphiles of growing importance, with the goal of replacing synthetic surfactants in commercial formulations. However, their cytotoxicity profile is still poorly known, especially for new molecules like single-glucose lipids or bolaform sophorolipids. This wants to contribute to all those applications, which could be developed with biosurfactants in contact with the skin (cosmetics, wound healing). We test the cytotoxicity of five structurally-related molecules (C18:1 and C18:0 sophorolipids, C18:1 and C18:0 single-glucose lipids, C18:1 di-sophoroside) against normal human dermal fibroblasts (NHDF) and evaluate the metabolic activity of the least toxic among them. To the best of our knowledge, cytotoxicity of these molecules, and of microbial biosurfactants in general, was never tested against NHDF.

Comparative effects of various extracellular vesicle subpopulations derived from clonal mesenchymal stromal cells on cultured fibroblasts in wound healing-related process

INTRODUCTION

Non-healing wounds pose significant challenges and require effective therapeutic interventions. Extracellular vesicles (EVs) have emerged as promising cell-free therapeutic agents in tissue regeneration. However, the functional differences between different subpopulations of EVs in wound healing remain understudied. This study aimed to evaluate the effects of two distinct subpopulations of clonal mesenchymal stromal cells (cMSC)-derived EVs (cMSC-EVs), namely 20K and 110K-cMSC-EVs, primarily on in vitro wound healing process, providing fast and cost-effective alternatives to animal models.

METHODS

In vitro assays were conducted to compare the effects of 20K and 110K-cMSC-EVs, isolated through high-speed centrifugation and differential ultracentrifugation, respectively. For evaluation the main mechanisms of wound healing, including cell proliferation, cell migration, angiogenesis, and contraction. Human dermal fibroblasts (HDF) were considered as the main cells for analysis of these procedures. Moreover, gene expression analysis was performed to assess the impact of these EV subpopulations on the related process of wound healing on HDF.

RESULTS

The results demonstrated that both 20K and 110K-cMSC-EVs exhibited beneficial effects on cell proliferation, cell migration, angiogenesis, and gel contraction. RT-qPCR revealed that both EV types downregulated interleukin 6 (IL6), induced proliferation by upregulating proliferating cell nuclear antigen (PCNA), and regulated remodeling by upregulating matrix metallopeptidase 1 (MMP1) and downregulating collagen type 1 (COL1).

DISCUSSION

This study highlights the effects of both 20K and 110K-cMSC-EVs on the potency of HDFs in wound healing-related process. As the notable finding, 20K-cMSC-EVs offer a more feasible and cost-effective subpopulation for isolation and follow the GMP standard, recommended to utilize this fraction for therapeutic application.

The role of biomaterials-based scaffolds in advancing skin tissue construct

Despite extensive clinical studies and therapeutic interventions, addressing significant skin wounds remains challenging, necessitating novel approaches for effective regeneration therapy. In the current review, we analyzed and evaluated the application, advancements, and future directions of biomaterials-based scaffolds for skin tissue construct. In addition, we investigated the role of other biological substitutes in promoting wound healing and skin tissue regeneration. The review highlights the impact of biomaterial-based scaffolds on skin tissue regeneration and wound healing. After presenting the physiological process of skin tissue regeneration, the review emphasizes the different biochemical components significant for skin healing and regeneration. Subsequently, it delves into the role of scaffolds in skin tissue engineering. Recent advancements in nanotechnology are also highlighted with a specific focus on the utilization of nanomaterials for enhancing healing, facilitating tissue regeneration, and promoting skin reconstruction. Biomaterial scaffolds have emerged as a potential intervention for wound healing forming the foundation of skin tissue regeneration. These scaffolds, intricate three-dimensional frameworks, serve as carriers for cells, medications, and genes, facilitating their delivery into the body. The integration of degradable porous scaffolds with biological cells offers a promising avenue for tissue repair. Biomaterials play a crucial role in tissue engineering, providing temporary mechanical support and facilitating cellular processes to augment skin tissue regeneration.

Preparation of thermoresponsive & enzymatically crosslinkable gelatin-gellan gum bioink: A protein-polysaccharide hydrogel for 3D bioprinting of complex soft tissues

Developing superior bioinks present several challenges in achieving ideal properties such as biocompatibility, viscosity, degradation rates & mechanical properties which are required to make functional tissue constructs. Various attempts have been made to prepare excellent bioink compositions that are suitable to address the above challenges. Herein, a versatile combination of gelatin (GL) - gellan gum (GG) bioink was successfully formulated & the bioink 7.5GL/2GG was found to be ideal for printing complex and highly intricate structures with excellent shape fidelity. Two different crosslinkers namely transglutaminase (TG) and calcium chloride (CaCl2) were utilized for crosslinking. The rheological properties of GL/GG bioink indicated that TG and dual (TG + CaCl2) crosslinked constructs had storage modulus equivalent to the that of native skin. Direct and indirect cytotoxicity assays revealed that the developed constructs were cytocompatible as well as hemocompatible. The 3D bioprinted GL/GG constructs crosslinked with only TG showed better cell viability, proliferation, cell spreading and wound healing efficiency in vitro compared to dual crosslinked constructs. In conclusion, TG crosslinking of 7.5GL/2GG bioink was ideal for bioprinting of skin tissue constructs for regenerative medicine applications. By altering the concentrations & printing conditions, this bioink may be tuned for other soft tissue engineering applications.

YAP/TAZ Drive Agrin-Matrix Metalloproteinase 12-Mediated Diabetic Skin Wound Healing

Macroscopic loss of extracellular matrix can lead to chronic defects in skin wound healing, but supplementation of extracellular matrix holds promise for facilitating wound closure, particularly in diabetic wound healing. We recently showed that the extracellular matrix proteoglycan agrin accelerates cutaneous wound healing by improving mechanoperception of migrating keratinocytes and allowing them to respond to mechanical stresses through matrix metalloproteinase 12 (MMP12). RNA-sequencing analysis revealed that in addition to a disorganized extracellular matrix, agrin-depleted skin cells have impaired YAP/TAZ transcriptional outcomes, leading us to hypothesize that YAP/TAZ, as central mechanosensors, drive the functionality of agrin-MMP12 signaling during cutaneous wound repair. In this study, we demonstrate that agrin activates YAP/TAZ during migration of keratinocytes after wounding in vitro and in vivo. Mechanistically, YAP/TAZ sustain agrin and MMP12 protein expression during migration after wounding through positive feedback. YAP/TAZ silencing abolishes agrin-MMP12-mediated force recognition and geometrical constraints. Importantly, soluble agrin therapy accelerates wound closure in diabetic mouse models by engaging MMP12-YAP. Because patients with diabetic foot ulcers and impaired wound healing have reduced expression of agrin-MMP12 that correlates with YAP/TAZ inactivation, we propose that timely activation of YAP/TAZ by soluble agrin therapy can accentuate mechanobiological microenvironments for efficient wound healing, under normal and diabetic conditions.

Chitosan/Alginate-Based Hydrogel Loaded With VE-Cadherin/FGF as Scaffolds for Wound Repair in Different Degrees of Skin Burns

Burns are complex traumatic injuries that lead to severe physical and psychological problems due to the prolonged healing period and resulting physical scars. Owing to their versatility, hydrogels can be loaded with various functional factors, making them promising wound dressings. However, many hydrogel dressings cannot support cell survival for a long time, thereby delaying the process of tissue repair. Herein, based on chitosan (CS)/alginate (SA)/poly(ethylene glycol) diacrylate (PEGDA), a basic hydrogel with hemostasis and antibacterial properties was prepared, and loaded with vascular endothelial cadherin (VE-cadherin) and fibroblast growth factors (FGF) to promote the co-culture of various skin cells, suitable for treating various skin injury types: (1) Construct a three-dimensional microenvironment conducive to the release of drugs and factors using natural biological macromolecules CS/SA. (2) Promote the cell growth by loading growth factors. (3) Establish skin burn models of different degrees and observe the repair process. From the results, the 3D microenvironment provided by hydrogel could support the active growth of cells for 12 days. Furthermore, deep burns with full-thickness skin were substantially repaired within about 24 days. Collectively, CS/SA hydrogel containing VE-cadherin and FGF can promote tissue healing in wounds with necrotic tissue, making it an ideal candidate for burn treatment.

Hyperglycemia-responsive nitric oxide-releasing biohybrid cryogels with cascade enzyme catalysis for enhanced healing of infected diabetic wounds

Diabetic wound infections are a frequent complication for diabetic patients, and conventional treatment for combating diabetic wound infections relies on antibiotics. However, the misuse and overuse of antibiotics have led to the emergence of drug-resistant bacteria, making these infections challenging to treat. Thus, there is an urgent need for alternative strategies to effectively manage diabetic wound infections. Herein, we have developed a hyperglycemia-responsive antibacterial cryogel system that can generate and release hydrogen peroxide (H2O2) and nitric oxide (NO). This system involves incorporating glucose oxidase (GO) and L-Arginine (L-Arg: A) into hyaluronic acid aldehyde methacryloyl (HAAMA: H) and gelatin methacryloyl (GelMA: G) hybrid cryogels (GOA@HG). HAAMA facilitated higher loading and longer stability of L-Arg and GO via a Schiff base reaction. In vitro studies demonstrate that GOA@HG cryogels exhibited outstanding breathability, effective exudate management, and excellent hemostasis capabilities. Moreover, this system could consume excess glucose in diabetic wounds and efficiently eliminate bacteria through the cascaded release of H2O2 and NO without causing antibiotic resistance. In vivo studies further reveal that GOA@HG cryogels significantly enhanced the healing of infected diabetic wounds by inhibiting bacterial growth, accelerating blood vessel formation, and promoting collagen deposition. Overall, GOA@HG cryogels displayed remarkable wound dressing properties and synergistic antimicrobial effects owing to glucose-responsive H2O2 and NO release, which could serve as a highly efficient therapeutic strategy for treating infected diabetic wounds.

Alteration of skin fibroblast steady state contributes to healing outcomes

Fibroblasts display complex functions associated with distinct gene expression profiles that influence matrix production and cell communications and the autonomy of tissue development and repair. Thrombospondin-2 (TSP-2), produced by fibroblasts, is a potent angiogenesis inhibitor and negatively associated with tissue repair. Single-cell (sc) sequencing analysis on WT and TSP2KO skin fibroblasts demonstrate distinct cell heterogeneity. Specifically, we found an enrichment of Sox10+ multipotent progenitor cells, identified as Schwann precursor cells, in TSP2KO fibroblasts, while fibrosis-related subpopulations decreased. Immunostaining of tissue and cells validated the increase of this Sox10+ population in KO fibroblasts. Furthermore, in silico analysis suggested enhanced pro-survival signaling, including WNT, TGF-β, and PDGF-β, alongside a reduced BMP4 response. Additionally, the creation of two TSP2KO NIH3T3 cell lines using the CRISPR/Cas9 technique allowed functional and signaling validation in a less complex system. Moreover, KO 3T3 cells exhibited enhanced migration and proliferation, with elevated levels of pro-regenerative molecules including TGF-β3 and Wnt4, and enrichment of nuclear β-catenin. These functional and molecular alterations likely contribute to improved healing and increased neurogenesis in TSP2-deficient wounds. Overall, our findings describe the heterogeneity of dermal fibroblasts and identify pro-regenerative features of TSP2KO fibroblasts.

Innervated Coculture Device to Model Peripheral Nerve-Mediated Fibroblast Activation

Cutaneous wound healing is a complex process involving various cellular and molecular interactions, resulting in the formation of a collagen-rich scar with imperfect function and morphology. Dermal fibroblasts are crucial to successful wound healing, migrating to the wound site where they are activated to provide extracellular matrix remodeling and wound closure. Peripheral nerves have been shown to play an important role in wound healing, with loss or damage to these nerves often leading to impaired healing and the formation of chronic nonhealing wounds. Previous research has suggested that sensory nerves secrete trophic factors that can regulate wound healing, including fibroblast activation; however, the direct cell-cell interaction between nerves and fibroblasts has not been extensively studied. To address this knowledge gap, we developed an in vitro co-culture model using a device called the IFlowPlate. This model supports the long-term viability of multiple cell types while allowing for direct contact between sensory nerve cells and dermal fibroblasts. Using the IFlowPlate, we demonstrate that co-culture of dorsal root ganglia with dermal fibroblasts increases fibroblast proliferation, collagen and α-smooth muscle actin expression, and secretion of pro-wound healing factors, suggesting that nerves can promote wound healing by modulating fibroblast activation. The IFlowPlate offers a user-friendly and high-throughput platform to study the in vitro interactions between nerves and a variety of cell types that can be applied to wound healing and other important biological processes.

Hierarchical double-layer microneedles accomplish multicenter skin regeneration in diabetic full-thickness wounds

INTRODUCTION

Managing large chronic wounds presents significant challenges because of inadequate donor sites, infection, and lack of structural support from dermal substitutes. Hydrogels are extensively used in various forms to promote chronic wound healing and provide a three-dimensional spatial structure, through growth factors or cell transport.

OBJECTIVES

We present a novel multicenter regenerative model that is capable of regenerating and merging simultaneously to form a complete layer of skin. This method significantly reduces wound healing time compared to the traditional centripetal healing model. We believe that our model can improve clinical outcomes and pave the way for further research into regenerative medicine.

METHODS

We prepared a novel multi-island double-layer microneedle (MDMN) using gelatin-methacryloylchitosan (GelMA-CS). The MDMN was loaded with keratinocytes (KCs) and dermal fibroblasts (FBs). Our aim in this study was to explore the therapeutic potential of MDMN in a total skin excision model.

RESULTS

The MDMN model replicated the layered structure of full-thickness skin and facilitated tissue regeneration and healing via dual omni-bearing. Multi-island regeneration centres accomplished horizontal multicentric regeneration, while epidermal and dermal cells migrated synchronously from each location. This produced a healing area approximately 4.7 times greater than that of the conventional scratch tests. The MDMN model exhibited excellent antibacterial properties, attributed to the chitosan layer. During wound healing in diabetic mice, the MDMN achieved earlier epidermal coverage and faster wound healing through multi-island regeneration centres and the omnidirectional regeneration mode. The MDMN group displayed an accelerated wound healing rate upon arrival at the destination (0.96 % ± 0.58 % vs. 4.61 % ± 0.32 %). Additionally, the MDMN group exhibited superior vascularization and orderly collagen deposition.

CONCLUSION

The present study presents a novel skin regeneration model using microneedles as carriers of autologous keratinocytes and dermal fibroblasts, which allows for omni-directional, multi-center, and full-thickness skin regeneration.

Dynamic polysaccharide/platelet-rich plasma hydrogels with synergistic antibacterial activities for accelerating infected wound healing

Platelet-rich plasma (PRP) has been recognized as an effective therapy in regenerative medicine and surgery, which can reduce the risk of antibiotic abuse and promote the healing of infected wounds. Recent advances in PRP-based treatments have focused on the controlled release of growth factors in PRP with biocompatible hydrogels and antimicrobial promotion by introducing hydrogel components or antibiotics, while the inherent antimicrobial activity of PRP is mostly neglected or sacrificed. Here, we demonstrate the combination of an antimicrobial polysaccharide, carboxymethyl chitosan, and PRP to construct an antimicrobial hydrogel via dynamic bonding with oxidized chondroitin sulfate. Significant inhibitory effects against Staphylococcus aureus and Escherichia coli (95 % of inhibition rate) are achieved through the synergistic contributions of the polysaccharide and PRP. Additionally, the resulting hydrogel promotes the migration of NIH-3T3 fibroblasts and collagen deposition by approximately 1.7 and 1.8 times, respectively, thereby accelerating the healing process of infected wounds. This work may bring new perspectives for potent applications of PRP-based hydrogel dressings for antibiotic-free management of infected wounds.

A ROS-Responsive Lipid Nanoparticles Release Multifunctional Hydrogel Based on Microenvironment Regulation Promotes Infected Diabetic Wound Healing

The continuous imbalance of the diabetic wound microenvironment is an important cause of chronic nonhealing, which manifests as a vicious cycle between excessive accumulation of reactive oxygen species (ROS) and abnormal healing. Regulating the microenvironment by suppressing wound inflammation, oxidative stress, and bacterial infection is a key challenge in treating diabetic wounds. In this study, ROS-responsive hydrogels are developed composed of silk fibroin methacrylated (SFMA), modified collagen type III (rCol3MA), and lipid nanoparticles (LNPs). The newly designed hydrogel system demonstrated stable physicochemical properties and excellent biocompatibility. Moreover, the release of antimicrobial peptide (AMP) and puerarin (PUE) demonstrated remarkable efficacy in eradicating bacteria, regulating inflammatory responses, and modulating vascular functions. This multifunctional hydrogel is a simple and efficient approach for the treatment of chronic diabetic infected wounds and holds tremendous potential for future clinical applications.

Histone Deacetylase 7-Derived 7-Amino Acid Peptide Increases Skin Wound Healing via Regulating Epidermal Fibroblast Proliferation and Migration

Due to the complexity of wound healing, how to achieve successful healing is a significant clinical challenge. In this study, we found that the histone deacetylase-7-derived 7-amino acid peptide (7A, MHSPGAD), especially its phosphorylated version 7Ap (MH[pSer]PGAD), increased dermal fibroblast cell HDFα proliferation and migration via elevated delta-catenin (CTNND1) serine phosphorylation-mediated beta-catenin (CTNNB) nuclear translocation and subsequent upregulation of c-Myc and cyclin D1 expression. 7Ap physically interacted with platelet-derived growth factor receptor (PDGFR) and increased PDGFR interaction with cyclin-dependent kinase 6 (CDK6). The PDGFR siRNA or CDK6 siRNA knockdown ablated 7AP-induced CTNND1 phosphorylation and subsequent c-Myc/cyclin D1 expression, indicating a novel 7Ap-PDGFR-CDK6-CTNND1/CTNNB signal pathway in regulating fibroblast proliferation and migration. Furthermore, 7Ap increased human umbilic vein endothelial cell proliferation and tube formation, suggesting an angiogenic effect. In a full-thickness excision wound rat model, the local administration of 50 ng/mL of 7Ap in hydrogel exerted a similar effect as 1 μg/mL vascular endothelial growth factor on accelerating wound healing, featured by enhanced fibroblast proliferation and migration, collagen deposition, and increased new vessel formation during the early phase of wound healing. Taken together, this study not only elicited a novel signal pathway in fibroblast proliferation but also paved an avenue to develop 7Ap as a treatment option for skin wound healing.

Propolis-loaded photocurable methacrylated pullulan films: Evaluation of mechanical, antibacterial, biocompatibility, wound healing and pro-angiogenic abilities

The ultimate goal of this study was to establish the groundwork for the development of high-mechanical pullulan based films for wound healing applications. For this purpose, pullulan (PUL) was successfully methacrylated with different methacrylic anhydride amounts and used for the fabrication of photocurable wound dressing films (PULMA). The mechanical properties of the films, evaluated by changing the methacrylation degree and polymer concentration for better mechanical performance, indicated the best results in terms of elastic modulus (2.55 ± 0.15 MPa), tensile strength (2.48 ± 0.12 MPa), and elongation at break (848 ± 111 %). Additionally, the incorporation of PRO into wound dressing films has demonstrated strong antibacterial activity against Escherichia coli and Staphylococcus aureus, and it has also improved the release profile. The obtained films have scavenging properties against 2,2-diphenyl-1-picrylhydrazyl (DPPH). The wound dressing films were not cytotoxic to NIH/3T3 cells, a fibroblast cell line, according to the cytotoxicity assay. The in vitro scratch test showed that PRO incorporated films induced cell migration, suggesting that they have the potential to close wounds and promote healing. According to the image analysis conducted following the in ovo chorioallantoic membrane (CAM) test, PRO inclusion boosted different angiogenesis parameters stemming from the films. Clear evidence has been found that PRO loaded into high mechanical performance PUL based films can be suitable for advanced wound dressing applications.

Electrical stimulation: a novel therapeutic strategy to heal biological wounds

Electrical stimulation (ES) has emerged as a powerful therapeutic modality for enhancing biological wound healing. This non-invasive technique utilizes low-level electrical currents to promote tissue regeneration and expedite the wound healing process. ES has been shown to accelerate wound closure, reduce inflammation, enhance angiogenesis, and modulate cell migration and proliferation through various mechanisms. The principle goal of wound management is the rapid recovery of the anatomical continuity of the skin, to prevent infections from the external environment and maintain homeostasis conditions inside. ES at the wound site is a compelling strategy for skin wound repair. Several ES applications are described in medical literature like AC, DC, and PC to improve cutaneous perfusion and accelerate wound healing. This review aimed to evaluate the primary factors and provides an overview of the potential benefits and mechanisms of ES in wound healing, and its ability to stimulate cellular responses, promote tissue regeneration, and improve overall healing outcomes. We also shed light on the application of ES which holds excellent promise as an adjunct therapy for various types of wounds, including chronic wounds, diabetic ulcers, and surgical incisions.

Trilayered nanocellulose-based patches loaded with acyclovir and hyaluronic acid for the treatment of herpetic lesions

This study focuses on the preparation of layered bacterial nanocellulose (BNC) patches for drug delivery and wound healing in the context of herpes labialis. Nanostructured patches were prepared by selective aqueous diffusion of acyclovir (ACV, antiviral drug), hyaluronic acid (HA, skin healing promoter), and glycerol (GLY, plasticizer and humectant) in the BNC network, followed by assembly into trilayered patches with ACV on the central layer of the patch (ACVT) or divided between two layers (ACVH), to modulate drug release. Both patches showed good layers' adhesion and thermal stability (125 °C), UV barrier properties, good static (Young's modulus up to 0.9 GPa (dry) and 0.7 GPa (wet)) and dynamic mechanical performance, and adhesion strength (21 kPa) comparable to or higher than other materials and commercial adhesives for wound healing. In vitro drug dissolution showed faster ACV release from the ACVH patch (77 ± 5 %, 10 min) than from the ACVT one (50 ± 7 %), suggesting efficient drug delivery. ACVH closely resembled a commercial cream formulation in terms of release and permeation profiles. The patches were non-cytotoxic toward L929 fibroblasts, promoting cell adhesion and wound closure (in vitro). These results underscore the dual-action potential of the layered patches for managing herpetic lesions.

Using Hybrid MnO2-Au Nanoflowers to Accelerate ROS Scavenging and Wound Healing in Diabetes

Objectives: Excessive reactive oxygen species (ROS) in diabetic wounds are major contributors to chronic wounds and impaired healing, posing significant challenges in regenerative medicine. Developing innovative drug delivery systems is crucial to address these issues by modifying the adverse microenvironment and promoting effective wound healing. Methods: Herein, we designed a novel drug delivery platform using manganese dioxide nanoflower hybridized gold nanoparticle composites (MnO2-Au) synthesized via a hydrothermal reaction, and investigated the potential of MnO2-Au nanoflowers to relieve the high oxidative stress microenvironment and regulate diabetic wound tissue healing. Results: This hybrid material demonstrated superior catalytic activity compared to MnO2 alone, enabling the rapid decomposition of hydrogen peroxide and a substantial reduction in ROS levels within dermal fibroblasts. The MnO2-Au nanoflowers also facilitated enhanced dermal fibroblast migration and Col-I expression, which are critical for tissue regeneration. Additionally, a hydrogel-based wound dressing incorporating MnO2-Au nanoflowers was developed, showing its potential as an intelligent drug delivery system. This dressing significantly reduced oxidative stress, accelerated wound closure, and improved the quality of neonatal epithelial tissue regeneration in a diabetic rat skin defect model. Conclusions: Our findings underscore the potential of MnO2-Au nanoflower-based drug delivery systems as a promising therapeutic approach for chronic wound healing, particularly in regenerative medicine.

Deciphering the Dysregulating IGF-1-SP1-CD248 Pathway in Fibroblast Functionality during Diabetic Wound Healing

Reduced fibroblast activity is a critical factor in the progression of diabetic ulcers. CD248, a transmembrane glycoprotein prominently expressed in activated fibroblasts, plays a pivotal role in wound healing. However, the role of CD248 in diabetic wound healing and the CD248 regulatory pathway remains largely unexplored. Our study shows that CD248 expression is significantly reduced in skin wounds from both patients and mice with diabetes. Single-cell transcriptome data analyses reveal a marked reduction of CD248-enriched secretory-reticular fibroblasts in diabetic wounds. We identify IGF-1 as a key regulator of CD248 expression through the protein kinase B/mTOR signaling pathway and the SP1 transcription factor. Overexpression of CD248 enhances fibroblast motility, elucidating the under-representation of CD248-enriched fibroblasts in diabetic wounds. Immunohistochemical staining of diabetic wound samples further confirms low SP1 expression and fewer CD248-positive secretory-reticular fibroblasts. Further investigation reveals that elevated TNFα levels in diabetic environment promotes IGF-1 resistance, and inhibiting IGF-1 induced CD248 expression. In summary, our findings underscore the critical role of the IGF1-SP1-CD248 axis in activating reticular fibroblasts during wound-healing processes. Targeting this axis in fibroblasts could help develop a therapeutic regimen for diabetic ulcers.

Maleimide conjugated PEGylated liposomal antibiotic to combat multi-drug resistant Escherichia coli and Klebsiella pneumoniae with enhanced wound healing potential

Antibiotic resistance is a significant threat, leaving us vulnerable to bacterial infections. Novel strategies are needed to combat bacterial resistance beyond discovering new antibiotics. This research focuses on using maleimide conjugated PEGylated liposomes (Mal-PL-Ab) to individually encapsulate a variety of antibiotics (ceftriaxone, cephalexin, doxycycline, piperacillin, ampicillin, and ceftazidime) and enhance their delivery against multi-drug resistant (MDR) bacteria like Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae). Mal-PL-Ab, with an average size of 84.2 nm ± 4.32 nm, successfully encapsulated these antibiotics with an encapsulation efficiency of 37.73 ± 3.19%. Compared to non-PEGylated liposomes (L-Ab), Mal-PL-Ab exhibited reduced toxicity in human dermal cells, emphasizing the importance of PEGylation in minimizing adverse effects. Mal-PL-Ab significantly decreased the minimum inhibitory concentration (MIC) values against both E. coli and K. pneumoniae by 9.33-fold and eightfold reduction (compared to non-PEGylated liposomes with 2.33-fold and 2.33fold reduction), respectively, indicating enhanced efficacy against MDR strains. Furthermore, in vitro scratch assay and gene expression analysis of human dermal fibroblast revealed that Mal-PL-Ab promoted cell proliferation, migration, and wound healing through upregulation of cell cycle, DNA repair, and angiogenesis-related genes. Harnessing the power of encapsulation, Mal-PL-Ab presents a novel avenue for enhanced antibiotic delivery and wound healing, potentially transcending the limitations of traditional options.

OxInflammatory Responses in the Wound Healing Process: A Systematic Review

Significant sums are spent every year to find effective treatments to control inflammation and speed up the repair of damaged skin. This study investigated the main mechanisms involved in the skin wound cure. Consequently, it offered guidance to develop new therapies to control OxInflammation and infection and decrease functional loss and cost issues. This systematic review was conducted using the PRISMA guidelines, with a structured search in the MEDLINE (PubMed), Scopus, and Web of Science databases, analyzing 23 original studies. Bias analysis and study quality were assessed using the SYRCLE tool (Prospero number is CRD262 936). Our results highlight the activation of membrane receptors (IFN-δ, TNF-α, toll-like) in phagocytes, especially macrophages, during early wound healing. The STAT1, IP3, and NF-kβ pathways are positively regulated, while Ca2+ mobilization correlates with ROS production and NLRP3 inflammasome activation. This pathway activation leads to the proteolytic cleavage of caspase-1, releasing IL-1β and IL-18, which are responsible for immune modulation and vasodilation. Mediators such as IL-1, iNOS, TNF-α, and TGF-β are released, influencing pro- and anti-inflammatory cascades, increasing ROS levels, and inducing the oxidation of lipids, proteins, and DNA. During healing, the respiratory burst depletes antioxidant defenses (SOD, CAT, GST), creating a pro-oxidative environment. The IFN-δ pathway, ROS production, and inflammatory markers establish a positive feedback loop, recruiting more polymorphonuclear cells and reinforcing the positive interaction between oxidative stress and inflammation. This process is crucial because, in the immune system, the vicious positive cycle between ROS, the oxidative environment, and, above all, the activation of the NLRP3 inflammasome inappropriately triggers hypoxia, increases ROS levels, activates pro-inflammatory cytokines and inhibits the antioxidant action and resolution of anti-inflammatory cytokines, contributing to the evolution of chronic inflammation and tissue damage.

Biomaterials for extrusion-based bioprinting and biomedical applications

Amongst the range of bioprinting technologies currently available, bioprinting by material extrusion is gaining increasing popularity due to accessibility, low cost, and the absence of energy sources, such as lasers, which may significantly damage the cells. New applications of extrusion-based bioprinting are systematically emerging in the biomedical field in relation to tissue and organ fabrication. Extrusion-based bioprinting presents a series of specific challenges in relation to achievable resolutions, accuracy and speed. Resolution and accuracy in particular are of paramount importance for the realization of microstructures (for example, vascularization) within tissues and organs. Another major theme of research is cell survival and functional preservation, as extruded bioinks have cells subjected to considerable shear stresses as they travel through the extrusion apparatus. Here, an overview of the main available extrusion-based printing technologies and related families of bioprinting materials (bioinks) is provided. The main challenges related to achieving resolution and accuracy whilst assuring cell viability and function are discussed in relation to specific application contexts in the field of tissue and organ fabrication.

miR-146a Decreases Inflammation and ROS Production in Aged Dermal Fibroblasts

Aging is associated with a decline in the functionality of various cell types, including dermal fibroblasts, which play a crucial role in maintaining skin homeostasis and wound healing. Chronic inflammation and increased reactive oxygen species (ROS) production are hallmark features of aging, contributing to impaired wound healing. MicroRNA-146a (miR-146a) has been implicated as a critical regulator of inflammation and oxidative stress in different cell types, yet its role in aged dermal fibroblasts and its potential relevance to wound healing remains poorly understood. We hypothesize that miR-146a is differentially expressed in aged dermal fibroblasts and that overexpression of miR-146a will decrease aging-induced inflammatory responses and ROS production. Primary dermal fibroblasts were isolated from the skin of 17-week-old (young) and 88-week-old (aged) mice. Overexpression of miR-146a was achieved through miR-146a mimic transfection. ROS were detected using a reliable fluorogenic marker, 2,7-dichlorofluorescin diacetate. Real-time PCR was used to quantify relative gene expression. Our investigation revealed a significant reduction in miR-146a expression in aged dermal fibroblasts compared to their younger counterparts. Moreover, aged dermal fibroblasts exhibited heightened levels of inflammatory responses and increased ROS production. Importantly, the overexpression of miR-146a through miR-146a mimic transfection led to a substantial reduction in inflammatory responses through modulation of the NF-kB pathway in aged dermal fibroblasts. Additionally, the overexpression of miR-146a led to a substantial decrease in ROS production, achieved through the downregulation of NOX4 expression in aged dermal fibroblasts. These findings underscore the pivotal role of miR-146a in mitigating both inflammatory responses and ROS production in aged dermal fibroblasts, highlighting its potential as a therapeutic target for addressing age-related skin wound healing.

Spiroconjugated 1,2,3-triazolo[5,1-b]1,3,4-thiadiazine stimulates functional activity of fibroblasts under skin injury regeneration

Background and purpose

One of the most important mechanisms of tissue regeneration is the high functional activity of cells, including proliferation. Currently, there are practically no effective skin cell activators on the pharmaceutical market. The purpose of this work was to demonstrate the stimulating effect of spiroconjugated 1,2,3-triazolo[5,1-b]1,3,4-thiadiazine (STT) on the functional activity of fibroblasts.

Experimental approach

STT containing ointment for dermal application was made. To assess in vivo effect of the STT a linear wound model in rats was tested. A combination of histological techniques and mechanical testing was employed to estimate the stimulating effect of STT on the functional activity of fibroblasts.

Findings/Results

The STT significantly increased the number of fibroblasts as well as the density and order of produced collagen fibers in the dermis during the wound healing process. As a result, a tissue was formed at the site of damage with the structure corresponding to normal skin. In addition, skin functions were restored, in particular mechanically.

Conclusion and implications

The results suggested the stimulating effect of the STT on fibroblast activity and demonstrated its potential for skin regeneration.

Farnesol repurposing for prevention and treatment of Acinetobacter baumannii biofilms

Acinetobacter baumannii has emerged as a multidrug-resistant (MDR) superbug by causing severe infections, with high mortality rates. The ability of A. baumannii to form biofilms significantly contributes to its persistence in diverse environmental and hospital settings. Here we report that farnesol, an FDA-approved commercial cosmetic and flavoring agent, demonstrates efficacy for both inhibition of biofilm formation, and disruption of established A. baumannii biofilms. Moreover, no resistance to farnesol was observed even after prolonged culture in the presence of sub-inhibitory farnesol doses. Farnesol combats A. baumannii biofilms by direct killing, while also facilitating biofilm detachment. Furthermore, farnesol was safe, and effective, for both prevention and treatment of A. baumannii biofilms in an ex vivo burned human skin model. Since current treatment options for A. baumannii biofilm infections were mainly counted on the combination therapy of last-resort antibiotics, and clearly non-sustainable due to robust MDR phenotype of A. baumannii, we propose that farnesol alone can be repurposed as a highly effective agent for both preventing and treating life-threating biofilm-associated infections of A. baumannii due to its proven safety, convenient topical delivery, and excellent efficiency, plus its superiority of evading resistance development.

Exosome-mimetic vesicles derived from fibroblasts carrying matrine for wound healing

Background

Chronic skin wounds are a leading cause of hospital admissions and reduced life expectancy among older people and individuals with diabetes. Delayed wound healing is often attributed to a series of cellular abnormalities. Matrine, a well-studied component found in Sophora flavescens, is recognized for its anti-inflammatory effects. However, its impact on wound healing still remains uncertain. This study aims to explore the potential of matrine in promoting wound healing.

Methods

In this study, we utilized gradient extrusion to produce fibroblast-derived exosome-mimetic vesicles as carriers for matrine (MHEM). MHEM were characterized using transmission electron microscopy and dynamic light scattering analysis. The therapeutic effect of MHEM in wound healing was explored in vitro and in vivo.

Results

Both matrine and MHEM enhanced the cellular activity as well as the migration of fibroblasts and keratinocytes. The potent anti-inflammatory effect of matrine diluted the inflammatory response in the vicinity of wounds. Furthermore, MHEM worked together to promote angiogenesis and the expression of transforming growth factor β and collagen I. MHEM contained growth factors of fibroblasts that regulated the functions of fibroblasts, keratinocytes and monocytes, which synergistically promoted wound healing with the anti-inflammatory effect of matrine.

Conclusions

MHEM showed enhanced therapeutic efficacy in the inflammatory microenvironment, for new tissue formation and angiogenesis of wound healing.

Dual FGFR-targeting and pH-activatable ruthenium-peptide conjugates for targeted therapy of breast cancer

Dysregulation of Fibroblast Growth Factor Receptors (FGFRs) signaling has been associated with breast cancer, yet employing FGFR-targeted delivery systems to improve the efficacy of cytotoxic agents is still sparsely exploited. Herein, we report four new bi-functional ruthenium-peptide conjugates (RuPCs) with FGFR-targeting and pH-dependent releasing abilities, envisioning the selective delivery of cytotoxic Ru complexes to FGFR(+)-breast cancer cells, and controlled activation at the acidic tumoral microenvironment. The antiproliferative potential of the RuPCs and free Ru complexes was evaluated in four breast cancer cell lines with different FGFR expression levels (SKBR-3, MDA-MB-134-VI, MCF-7, and MDA-MB-231) and in human dermal fibroblasts (HDF), at pH 6.8 and pH 7.4 aimed at mimicking the tumor microenvironment and normal tissues/bloodstream pHs, respectively. The RuPCs showed higher cytotoxicity in cells with higher level of FGFR expression at acidic pH. Additionally, RuPCs showed up to 6-fold higher activity in the FGFR(+) breast cancer lines compared to the normal cell line. The release profile of Ru complexes from RuPCs corroborates the antiproliferative effects observed. Remarkably, the cytotoxicity and releasing ability of RuPCs were shown to be strongly dependent on the conjugation of the peptide position in the Ru complex. Complementary molecular dynamic simulations and computational calculations were performed to help interpret these findings at the molecular level. In summary, we identified a lead bi-functional RuPC that holds strong potential as a FGFR-targeted chemotherapeutic agent.

miR-21 Expressed by Dermal Fibroblasts Enhances Skin Wound Healing Through the Regulation of Inflammatory Cytokine Expression

The management of skin wound healing is still a challenge. MicroRNA-21 (miR-21) has been reported to play important roles in wound repair; however, the underlying mechanism needs to be further clarified. The present study aimed to study the direct role of miR-21 in skin wound healing in miR-21 KO mice and to investigate the role of miR-21 in controlling the migration and proliferation of primary human skin cells and its underlying mechanism(s). miR-21 KO and wild-type (WT) mice were used for in vivo wound healing assays, while mouse and human primary skin cells were used for in vitro assays. miR-21 inhibitors or mimics or negative control small RNAs were transfected to either inhibit or enhance miR-21 expression in the human primary dermal fibroblasts or epidermal cells. RNA sequencing analysis was performed to identify the potential molecular pathways involved. We found that the loss of miR-21 resulted in slower wound healing in miR-21 KO mouse skin and especially delayed the healing of dermal tissue. In vitro assays demonstrated that the reduced expression of miR-21 caused by its inhibitor inhibited the migration of human primary dermal fibroblasts, which could be enhanced by increased miR-21 expression caused by miR-21 mimics. RNA-sequence analysis revealed that the inhibition of miR-21 expression downregulated the inflammatory response pathways associated with the decreased expression of inflammatory cytokines, and the addition of IL-1β into the culture medium enhanced the migration and proliferation of dermal fibroblasts in vitro. In conclusion, miR-21 in dermal fibroblasts can promote the migration and growth of epidermal and dermal cells to enhance skin wound healing through controlling the expression of inflammatory cytokines.

Unremitting pro-inflammatory T-cell phenotypes, and macrophage activity, following paediatric burn injury

Objectives

The aim of this study was to characterise the dynamic immune profile of paediatric burn patients for up to 18 months post-burn.

Methods

Flow cytometry was used to measure 25 cell markers, chemokines and cytokines which reflected both pro-inflammatory and anti-inflammatory immune profiles. Peripheral blood mononuclear cells from 6 paediatric burn patients who had returned for repeated burn and scar treatments for > 4 timepoints within 12 months post-burn were compared to four age-matched healthy controls.

Results

While overall proportions of T cells, NK cells and macrophages remained relatively constant, over time percentages of these immune cells differentiated into effector and proinflammatory cell phenotypes including Th17 and activated γδ T cells. Circulating proportions of γδ T cells increased their expression of pro-inflammatory mediators throughout the burn recovery, with a 3-6 fold increase of IL-17 at 1-3 weeks, and NFκβ 9-18 months post-burn. T-regulatory cell plasticity was also observed, and Treg phenotype proportions changed from systemically reduced skin-homing T-regs (CCR4+) and increased inflammatory (CCR6+) at 1-month post-burn, to double-positive cell types (CCR4+CCR6+) elevated in circulation for 18 months post-burn. Furthermore, Tregs were observed to proportionally express less IL-10 but increased TNF-α over 18 months.

Conclusion

Overall, these results indicate the circulating percentages of immune cells do not increase or decrease over time post-burn, instead they become highly specialised, inflammatory and skin-homing. In this patient population, these changes persisted for at least 18 months post-burn, this 'immune distraction' may limit the ability of immune cells to prioritise other threats post-burn, such as respiratory infections.

An Electroconductive and Antibacterial Adhesive Nanocomposite Hydrogel for High-Performance Skin Wound Healing

Multifunctional hydrogel adhesives inhibiting infections and enabling the electrical stimulation (ES) of tissue reparation are highly desirable for the healing of surgical wounds and other skin injuries. Herein, a therapeutic nanocomposite hydrogel is designed by integrating β-cyclodextrin-embedded Ag nanoparticles (CDAgNPs) in a polyvinyl alcohol (PVA) matrix enhanced with free β-cyclodextrin (CD) and an atypical macromolecule made of β-glucan grafted with hyaluronic acid (HAG). The main objective is to develop a biocompatible dressing combining the electroconductivity and antibacterial activity of CDAgNPs with the cohesiveness and porosity of PVA and the anti-inflammatory, moisturizing, and cell proliferation-promoting properties of HAG. The last component, CD, is added to strengthen the network structure of the hydrogel. PVA/CD/HAG/CDAgNP exhibited excellent adhesion strength, biocompatibility, electroconductivity, and antimicrobial activity against a wide range of bacteria. In addition, the nanocomposite hydrogel has a swelling ratio and water retention capacity suitable to serve as a wound dressing. PVA/CD/HAG/CDAgNP promoted the proliferation of fibroblast in vitro, accelerated the healing of skin wounds in an animal model, and is hemostatic. Upon ES, the PVA/CD/HAG/CDAgNP nanocomposite hydrogel became more efficient both in vitro and in vivo further speeding up the skin healing process thus demonstrating its potential as a next-generation electroconductive wound dressing.

Fibroblasts in Diabetic Foot Ulcers

Fibroblasts are stromal cells ubiquitously distributed in the body of nearly every organ tissue. These cells were previously considered to be "passive cells", solely responsible for ensuring the turnover of the extracellular matrix (ECM). However, their versatility, including their ability to switch phenotypes in response to tissue injury and dynamic activity in the maintenance of tissue specific homeostasis and integrity have been recently revealed by the innovation of technological tools such as genetically modified mouse models and single cell analysis. These highly plastic and heterogeneous cells equipped with multifaceted functions including the regulation of angiogenesis, inflammation as well as their innate stemness characteristics, play a central role in the delicately regulated process of wound healing. Fibroblast dysregulation underlies many chronic conditions, including cardiovascular diseases, cancer, inflammatory diseases, and diabetes mellitus (DM), which represent the current major causes of morbidity and mortality worldwide. Diabetic foot ulcer (DFU), one of the most severe complications of DM affects 40 to 60 million people. Chronic non-healing DFU wounds expose patients to substantial sequelae including infections, gangrene, amputation, and death. A complete understanding of the pathophysiology of DFU and targeting pathways involved in the dysregulation of fibroblasts are required for the development of innovative new therapeutic treatments, critically needed for these patients.

Self-assembled and dynamic bond crosslinked herb-polysaccharide hydrogel with anti-inflammation and pro-angiogenesis effects for burn wound healing

Excessive inflammation and defective angiogenesis can affect burn wound healing. Recently, naturally derived substances with anti-inflammatory and proangiogenic properties have attracted public attention. The design and fabrication of naturally derived substance-based bioactive hydrogels as wound dressings are of interest and important for regulating the complex microenvironment of the wound bed. Herein, we developed a hydrogel by self-assembling a natural herb (glycyrrhizic acid, GA) dynamic Schiff base crosslinking of hyaluronic acid derivatives and integrating deferoxamine (DFO). The naturally derived herbal GA endowed the bioactive hydrogel with a native anti-inflammatory capability. The introduction of dynamic bond crosslinking improved the hydrogel stability. In addition, dynamic crosslinking is conducive for integrating the naturally-derived DFO, delivering it to the wound site, and promoting angiogenesis. Rheological tests, injectability, degradation behavior, and drug release performance demonstrated the enhanced stability of the hydrogel and sustained release of DFO. Cytotoxicity, cell proliferation, and cell migration tests suggested that the hydrogel was biocompatible. Further, the hydrogel exerted anti-inflammatory and angiogenic effects and accelerated burn wound healing in rats. Therefore, the proposed hydrogel has the potential to be a natural, herb-based, bioactive dressing for burn wound management.

SOX family transcription factors as therapeutic targets in wound healing: A comprehensive review

The SOX family plays a vital role in determining the fate of cells and has garnered attention in the fields of cancer research and regenerative medicine. It also shows promise in the study of wound healing, as it actively participates in the healing processes of various tissues such as skin, fractures, tendons, and the cornea. However, our understanding of the mechanisms behind the SOX family's involvement in wound healing is limited compared to its role in cancer. Gaining insight into its role, distribution, interaction with other factors, and modifications in traumatized tissues could provide valuable new knowledge about wound healing. Based on current research, SOX2, SOX7, and SOX9 are the most promising members of the SOX family for future interventions in wound healing. SOX2 and SOX9 promote the renewal of cells, while SOX7 enhances the microvascular environment. The SOX family holds significant potential for advancing wound healing research. This article provides a comprehensive review of the latest research advancements and therapeutic tools related to the SOX family in wound healing, as well as the potential benefits and challenges of targeting the SOX family for wound treatment.

Dual-Cross-Linked Chitosan-Based Antibacterial Hydrogels with Tough and Adhesive Properties for Wound Dressing

Biocompatible chitosan-based hydrogels have attracted extensive attention in wound dressing due to their human skin-like tissue characteristics. However, it is a crucial challenge to fabricate chitosan-based hydrogels with versatile properties, including flexibility, stretchability, adhesivity, and antibacterial activity. In this work, a kind of chitosan-based hydrogels with integrated functionalities are facilely prepared by solution polymerization of acrylamide (AAm) and sodium p-styrene sulfonate (SS) in the presence of quaternized carboxymethyl chitosan (QCMCS). Due to the dual cross-linking between QCMCS and P(AAm-co-SS), the optimized QCMCS/P(AAm-co-SS) hydrogel exhibits tough mechanical properties (0.767 MPa tensile stress and 1100% fracture strain) and moderate tissue adhesion (11.4 kPa). Moreover, biological evaluation in vitro illustrated that as-prepared hydrogel possesses satisfactory biocompatibility, hemocompatibility, and excellent antibacterial ability (against S. aureus and E. coli are 98.8% and 97.3%, respectively). Then, the hydrogels are tested in a rat model for bacterial infection incision in vivo, and the results show that they can significantly accelerate epidermal regeneration and wound closure. This is due to their ability to reduce the inflammatory response, promote the formation of collagen deposition and granulation tissue. The proposed chitosan-based antibacterial hydrogels have the potential to be a highly effective wound dressing in clinical wound healing.

Targeting DNA methylation and demethylation in diabetic foot ulcers

BACKGROUND

Poor wound healing is a significant complication of diabetes, which is commonly caused by neuropathy, trauma, deformities, plantar hypertension and peripheral arterial disease. Diabetic foot ulcers (DFU) are difficult to heal, which makes patients susceptible to infections and can ultimately conduce to limb amputation or even death in severe cases. An increasing number of studies have found that epigenetic alterations are strongly associated with poor wound healing in diabetes.

AIM OF REVIEW

This work provides significant insights into the development of therapeutics for improving chronic diabetic wound healing, particularly by targeting and regulating DNA methylation and demethylation in DFU. Key scientific concepts of review: DNA methylation and demethylation play an important part in diabetic wound healing, via regulating corresponding signaling pathways in different breeds of cells, including macrophages, vascular endothelial cells and keratinocytes. In this review, we describe the four main phases of wound healing and their abnormality in diabetic patients. Furthermore, we provided an in-depth summary and discussion on how DNA methylation and demethylation regulate diabetic wound healing in different types of cells; and gave a brief summary on recent advances in applying cellular reprogramming techniques for improving diabetic wound healing.

Identifying characteristics of dermal fibroblasts in skin homeostasis and disease

Heterogeneous dermal fibroblasts are the main components that constitute the dermis. Distinct fibroblast subgroups show specific characteristics and functional plasticity that determine dermal structure during skin development and wound healing. Although researchers have described the roles of fibroblast subsets, this is not completely understood. We review recent evidence supporting understanding about the heterogeneity of fibroblasts. We summarize the origins and the identified profiles of fibroblast subpopulations. The characteristics of fibroblast subpopulations in both healthy and diseased states are highlighted, and the potential of subpopulations to be involved in wound healing in different ways was discussed. Additionally, we review the plasticity of subpopulations and the underlying signalling mechanisms. This review may provide greater insights into potential novel therapeutic targets and tissue regeneration strategies for the future.

2D Nanomaterials and Their Drug Conjugates for Phototherapy and Magnetic Hyperthermia Therapy of Cancer and Infections

Photothermal therapy (PTT) and magnetic hyperthermia therapy (MHT) using 2D nanomaterials (2DnMat) have recently emerged as promising alternative treatments for cancer and bacterial infections, both important global health challenges. The present review intends to provide not only a comprehensive overview, but also an integrative approach of the state-of-the-art knowledge on 2DnMat for PTT and MHT of cancer and infections. High surface area, high extinction coefficient in near-infra-red (NIR) region, responsiveness to external stimuli like magnetic fields, and the endless possibilities of surface functionalization, make 2DnMat ideal platforms for PTT and MHT. Most of these materials are biocompatible with mammalian cells, presenting some cytotoxicity against bacteria. However, each material must be comprehensively characterized physiochemically and biologically, since small variations can have significant biological impact. Highly efficient and selective in vitro and in vivo PTTs for the treatment of cancer and infections are reported, using a wide range of 2DnMat concentrations and incubation times. MHT is described to be more effective against bacterial infections than against cancer therapy. Despite the promising results attained, some challenges remain, such as improving 2DnMat conjugation with drugs, understanding their in vivo biodegradation, and refining the evaluation criteria to measure PTT or MHT effects.

Genetic analysis and multimodal imaging identify novel mtDNA 12148T>C leading to multisystem dysfunction with tissue-specific heteroplasmy

Patients with mitochondrial disorders present with clinically diverse symptoms, largely driven by heterogeneous mutations in mitochondrial-encoded and nuclear-encoded mitochondrial genes. These mutations ultimately lead to complex biochemical disorders with a myriad of clinical manifestations, often accumulating during childhood on into adulthood, contributing to life-altering and sometimes fatal events. It is therefore important to diagnose and characterize the associated disorders for each mitochondrial mutation as early as possible since medical management might be able to improve the quality and longevity of life in mitochondrial disease patients. Here we identify a novel mitochondrial variant in a mitochondrial transfer RNA for histidine (mt-tRNA-his) [m.12148T>C], that is associated with the development of ocular, aural, neurological, renal, and muscular dysfunctions. We provide a detailed account of a family harboring this mutation, as well as the molecular underpinnings contributing to cellular and mitochondrial dysfunction. In conclusion, this investigation provides clinical, biochemical, and morphological evidence of the pathogenicity of m.12148T>C. We highlight the importance of multiple tissue testing and in vitro disease modeling in diagnosing mitochondrial disease.

Synergistic wound repair effects of a composite hydrogel for delivering tumor-derived vesicles and S-nitrosoglutathione

Treating chronic wounds requires transition from proinflammatory M1 to anti-inflammatory M2 dominant macrophages. Based on the role of tumor extracellular vesicles (tEVs) in regulating the phenotypic switching from M1 to M2 macrophages, we propose that tEVs may have a beneficial impact on alleviating the overactive inflammatory microenvironment associated with refractory wounds. On the other hand, as a nitric oxide donor, S-nitrosoglutathione (GSNO) can regulate inflammation, promote angiogenesis, enhance matrix deposition, and facilitate wound healing. In this study, a guar gum-based hydrogel with tEVs and GSNO was designed for the treatment of diabetic refractory wounds. This hybrid hydrogel was formed through the phenyl borate bonds, which can automatically disintegrate in response to the high reactive oxygen species (ROS) level at the site of refractory diabetic wounds, releasing tEVs and GSNO. We conducted a comprehensive evaluation of this hydrogel in vitro, which demonstrated excellent performance. Meanwhile, using a full-thickness excision model in diabetic mice, the wounds exposed to the therapeutic hydrogel healed completely within 21 days. The increased closure rate was associated with macrophage polarization and collagen deposition, accelerated fibroblast proliferation, and increased angiogenesis in the regenerating tissues. Therefore, this multifunctional hybrid hydrogel appears to be promising for clinical applications.

Regulation of dermal fibroblasts by human neutrophil peptides

Human neutrophil peptides (HNPs) can induce cell proliferation and activation so their growth promoting activities may have potential clinical benefit. This study investigated the effects of HNPs on human dermal fibroblasts. Differential gene expression in HNP-treated cells and genes involved in regulating intracellular pathways were explored. Dermal fibroblasts were isolated from healthy neonatal foreskin and treated with HNPs in 2D and 3D cell culture systems. The expression of cell proliferation (Ki-67) gene and cell activation (COL1A1) gene plus their proteins was measured. Differential gene expression was determined using RNA-seq, and upregulated and downregulated genes were mapped onto intracellular pathways by KEGG analysis and Gene Ontology databases. HNPs significantly increased cell proliferation without cytotoxicity whilst HNP1 enhanced expression of COL1A1 and type I collagen production in 2D cells and 3D spheroids. RNA-sequencing analysis showed gene clustering with clear separation between HNP1-treated and control groups. A heatmap of top 50 differentially expressed genes was consistent among HNP1-treated samples. Most upregulated genes were associated with cell proliferation and activation as mapped into intracellular pathways whilst most downregulated genes belonged to steroid/arachidonic acid metabolism and inflammatory signaling pathways. HNP1 increased cell proliferation and activation but reduced lipid metabolism and inflammation.

Piezo1 in skin wound healing and related diseases: Mechanotransduction and therapeutic implications

Skin wound healing is a multifaceted and intricate process involving inflammation, tissue proliferation, and scar formation, all of which are accompanied by the continuous application of mechanical forces. Mechanotransduction is the mechanism by which the skin receives and reacts to physical signals from the internal and external environment, converting them into intracellular biochemical signals. This intricate process relies on specialized proteins known as mechanotransducers, with Piezo1 being a critical mechanosensitive ion channel that plays a central role in this process. This article provides an overview of the structural characteristics of Piezo1 and summarizes its effects on corresponding cells or tissues at different stages of skin trauma, including how it regulates skin sensation and skin-related diseases. The aim is to reveal the potential diagnostic and therapeutic value of Piezo1 in skin trauma and skin-related diseases. Piezo1 has been reported to be a vital mediator of mechanosensation and transduction in various organs and tissues. Given its high expression in the skin, Piezo1, as a significant cell membrane ion channel, is essential in activating intracellular signaling cascades that trigger several cellular physiological functions, including cell migration and muscle contraction. These functions contribute to the regulation and improvement of wound healing.

The immune function of dermal fibroblasts in skin defence against pathogens

Dermal fibroblasts are the main resident cells of the dermis. They have several significant functions related to wound healing, extracellular matrix production and hair cycling. Dermal fibroblasts can also act as sentinels in defence against infection. They express pattern recognition receptors such as toll-like receptors to sense pathogen components, followed by the synthesis of pro-inflammatory cytokines (including IL-6, IFN-β and TNF-α), chemokines (such as IL-8 and CXCL1) and antimicrobial peptides. Dermal fibroblasts also secrete other molecules-like growth factors and matrix metalloproteinases to benefit tissue repair from infection. Crosstalk between dermal fibroblasts and immune cells may amplify the immune response against infection. Moreover, the transition of a certain adipogenic fibroblasts to adipocytes protects skin from bacterial infection. Together, we discuss the role of dermal fibroblasts in the war against pathogens in this review. Dermal fibroblasts have important immune functions in anti-infection immunity, which should not be overlooked.

Potential Broad-Spectrum Antimicrobial, Wound Healing, and Disinfectant Cationic Peptide Crafted from Snake Venom

Antimicrobial cationic peptides are intriguing and propitious antibiotics for the future, even against multidrug-resistant superbugs. Venoms serve as a source of cutting-edge therapeutics and innovative, unexplored medicines. In this study, a novel cationic peptide library consisting of seven sequences was designed and synthesized from the snake venom cathelicidin, batroxicidin (BatxC), with the inclusion of the FLPII motif at the N-terminus. SP1V3_1 demonstrated exceptional antibacterial effectiveness against Escherichia coli, methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa, and Klebsiella pneumoniae and destroyed the bacteria by depolarizing, rupturing, and permeabilizing their membranes, as evident from fluorescence assays, atomic force microscopy, and scanning electron microscopy. SP1V3_1 was observed to modulate the immune response in LPS-elicited U937 cells and exhibited good antibiofilm activity against MRSA and K. pneumoniae. The peptide promoted wound healing and disinfection in the murine model. The study demonstrated that SP1V3_1 is an exciting peptide lead and may be explored further for the development of better therapeutic peptides.

Fibroblasts - the cellular choreographers of wound healing

Injuries to our skin trigger a cascade of spatially- and temporally-synchronized healing processes. During such endogenous wound repair, the role of fibroblasts is multifaceted, ranging from the activation and recruitment of innate immune cells through the synthesis and deposition of scar tissue to the conveyor belt-like transport of fascial connective tissue into wounds. A comprehensive understanding of fibroblast diversity and versatility in the healing machinery may help to decipher wound pathologies whilst laying the foundation for novel treatment modalities. In this review, we portray the diversity of fibroblasts and delineate their unique wound healing functions. In addition, we discuss future directions through a clinical-translational lens.

A Review of Metal Nanoparticles Embedded in Hydrogel Scaffolds for Wound Healing In Vivo

An evolving field, nanotechnology has made its mark in the fields of nanoscience, nanoparticles, nanomaterials, and nanomedicine. Specifically, metal nanoparticles have garnered attention for their diverse use and applicability to dressings for wound healing due to their antimicrobial properties. Given their convenient integration into wound dressings, there has been increasing focus dedicated to investigating the physical, mechanical, and biological characteristics of these nanoparticles as well as their incorporation into biocomposite materials, such as hydrogel scaffolds for use in lieu of antibiotics as well as to accelerate and ameliorate healing. Though rigorously tested and applied in both medical and non-medical applications, further investigations have not been carried out to bring metal nanoparticle-hydrogel composites into clinical practice. In this review, we provide an up-to-date, comprehensive review of advancements in the field, with emphasis on implications on wound healing in in vivo experiments.

Human Umbilical Mesenchymal Stem Cells-Derived Microvesicles Attenuate Formation of Hypertrophic Scar through Multiple Mechanisms

Mesenchymal stem cells and the derived extracellular microvesicles are potential promising therapy for many disease conditions, including wound healing. Since current therapeutic approaches do not satisfactorily attenuate or ameliorate formation of hypertrophic scars, it is necessary to develop novel drugs to achieve better outcomes. In this study, we investigated the effects and the underlying mechanisms of human umbilical mesenchymal stem cells (HUMSCs)-derived microvesicles (HUMSCs-MVs) on hypertrophic scar formation using a rabbit ear model and a human foreskin fibroblasts (HFF) culture model. The results showed that HUMSCs-MVs reduced formation of hypertrophic scar tissues in the rabbit model based on appearance observation, and hematoxylin and eosin (H&E), Masson, and immunohistochemical stainings. HUMSCs-MVs inhibited invasion of HFF cells and decreased the levels of the α-SMA, N-WASP, and cortacin proteins. HUMSCs-MVs also inhibited cell proliferation of HFF cells. The MMP-1, MMP-3, and TIMP-3 mRNA levels were significantly increased, and the TIMP-4 mRNA level and the NF-kB p65/β-catenin protein levels were significantly decreased in HFF cells after HUMSCs-MVs treatment. The p-SMAD2/3 levels and the ratios of p-SMAD2/3/SMAD2/3 were significantly decreased in both the wound healing tissues and HFF cells after HUMSCs-MVs treatment. CD34 levels were significantly decreased in both wound healing scar tissues and HFF cells after HUMSCs-MVs treatment. The VEGF-A level was also significantly decreased in HFF cells after HUMSCs-MVs treatment. The magnitudes of changes in these markers by HUMSCs-MVs were mostly higher than those by dexamethasone. These results suggested that HUMSCs-MVs attenuated formation of hypertrophic scar during wound healing through inhibiting proliferation and invasion of fibrotic cells, inflammation and oxidative stress, Smad2/3 activation, and angiogenesis. HUMSCs-MVs is a potential promising drug to attenuate formation of hypertrophic scar during wound healing.

A Triboelectric Nanocomposite for Sterile Sensing, Energy Harvesting, and Haptic Diagnostics in Interventional Procedures from Surgical Gloves

Advanced interfacial engineering has the potential to enable the successful realization of three features that are particularly important for a variety of healthcare applications: wettability control, antimicrobial activity to reduce infection risks, and sensing of physiological parameters. Here, a sprayable multifunctional triboelectric coating is exploited as a nontoxic, ultrathin tactile sensor that can be integrated directly on the fingertips of surgical gloves. The coating is based on a polymer blend mixed with zinc oxide (ZnO) nanoparticles, which enables antifouling and antibacterial properties. Additionally, the nanocomposite is superhydrophobic (self-cleaning) and is not cytotoxic. The coating is also triboelectric and can be applied directly onto surgical gloves with printed electrodes. The sensorized gloves so obtained enable mechanical energy harvesting, force sensing, and detection of materials stiffness changes directly from fingertip, which may complement proprioceptive feedback for clinicians. Just as importantly, the sensors also work with a second glove on top offering better reassurance regarding sterility in interventional procedures. As a case study of clinical use for stiffness detection, the sensors demonstrate successful detection of pig anal sphincter injury ex vivo. This may lead to improving the accuracy of diagnosing obstetric anal sphincter injury, resulting in prompt repair, fewer complications, and improved quality of life.

Assessment of different manufacturing techniques for the production of bioartificial scaffolds as soft organ transplant substitutes

Introduction: The problem of organs' shortage for transplantation is widely known: different manufacturing techniques such as Solvent casting, Electrospinning and 3D Printing were considered to produce bioartificial scaffolds for tissue engineering purposes and possible transplantation substitutes. The advantages of manufacturing techniques' combination to develop hybrid scaffolds with increased performing properties was also evaluated. Methods: Scaffolds were produced using poly-L-lactide-co-caprolactone (PLA-PCL) copolymer and characterized for their morphological, biological, and mechanical features. Results: Hybrid scaffolds showed the best properties in terms of viability (>100%) and cell adhesion. Furthermore, their mechanical properties were found to be comparable with the reference values for soft tissues (range 1-10 MPa). Discussion: The created hybrid scaffolds pave the way for the future development of more complex systems capable of supporting, from a morphological, mechanical, and biological standpoint, the physiological needs of the tissues/organs to be transplanted.

The total iridoid glycoside extract of Lamiophlomis rotata Kudo induces M2 macrophage polarization to accelerate wound healing by RAS/ p38 MAPK/NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Lamiophlomis rotata (Benth.) Kudo (L. rotata), a Tibetan medicinal plant, is used to treat "yellow-water diseases", such as skin disease, jaundice and rheumatism. Our previous study showed that the iridoid glycoside extract of L. rotata (IGLR) is the major constituent of skin wound healing. However, the role of IGLR in the biological process of trauma repair and the probable mechanism of the action remain largely unknown.

AIM OF THE STUDY

To investigate the role of IGLR in the biological process of trauma repair and the probable mechanism of the action.

MATERIALS AND METHODS

The role of IGLR in wound healing was investigated by overall skin wound in mice with Hematoxylin and Eosin (H&E) and Masson trichrome staining. The anti-inflammatory, angiogenesis-promoting and fibril formation effects of IGLR were visualized in wound skin tissue by immunofluorescence staining, and the proinflammatory factors and growth factors were assayed by real-time polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Macrophages, dermal fibroblasts, and endothelial cells were cultured to measure the direct/indirect interaction effects of IGLR on the proliferation and migration of cells, and flow cytometry was employed to assess the role of IGLR on macrophage phenotype. Network pharmacology combined with Western blot experiments were conducted to explore possible mechanisms of the actions.

RESULTS

IGLR increased the expression of CD206 (M2 markers) through the RAS/p38 MAPK/NF-κB signaling pathway during wound injury in vivo and in vitro. IGLR suppressed the inflammatory cytokines iNOS, IL-1β and TNF-α in the early stage of wound healing. During the proliferation step of wound repair, IGLR promoted angiogenesis and fibril formation by increasing the expression of VEGF, CD31, TGF-β and α-SMA in wound tissue, and similar results were verified by RT-PCR and ELISA. In a paracrine mechanism, the extract promoted the proliferation of dermal fibroblasts, and endothelial cells were founded by the conditioned medium (CM).

CONCLUSION

IGLR induced M2 macrophage polarization in the early stage of wound healing; in turn, IGLR played a key role in the transition from inflammation to cell proliferation during the biological process of wound healing.

Utilizing Robust Design to Optimize Composite Bioadhesive for Promoting Dermal Wound Repair

Catechol-modified bioadhesives generate hydrogen peroxide (H2O2) during the process of curing. A robust design experiment was utilized to tune the H2O2 release profile and adhesive performance of a catechol-modified polyethylene glycol (PEG) containing silica particles (SiP). An L9 orthogonal array was used to determine the relative contributions of four factors (the PEG architecture, PEG concentration, phosphate-buffered saline (PBS) concentration, and SiP concentration) at three factor levels to the performance of the composite adhesive. The PEG architecture and SiP wt% contributed the most to the variation in the results associated with the H2O2 release profile, as both factors affected the crosslinking of the adhesive matrix and SiP actively degraded the H2O2. The predicted values from this robust design experiment were used to select the adhesive formulations that released 40-80 µM of H2O2 and evaluate their ability to promote wound healing in a full-thickness murine dermal wound model. The treatment with the composite adhesive drastically increased the rate of the wound healing when compared to the untreated controls, while minimizing the epidermal hyperplasia. The release of H2O2 from the catechol and soluble silica from the SiP contributed to the recruitment of keratinocytes to the wound site and effectively promoted the wound healing.

3D co-culture of macrophages and fibroblasts in a sessile drop array for unveiling the role of macrophages in skin wound-healing

Three-dimensional (3D) heterotypic multicellular spheroid models play important roles in researches of the proliferation and remodeling phases in wound healing. This study aimed to develop a sessile drop array to cultivate 3D spheroids and simulate wound healing stage in vitro using NIH-3T3 fibroblasts and M2-type macrophages. By the aid of the offset of surface tension and gravity, the sessile drop array is able to transfer cell suspensions to spheroids via the superhydrophobic surface of each microwell. Meanwhile, each microwell has a cylinder hole at its bottom that provides adequate oxygen to the spheroid. It demonstrated that the NIH-3T3 fibroblast spheroid and the 3T3 fibroblast/M2-type macrophage heterotypic multicellular spheroid can form and maintain physiological activities within nine days. In order to further investigate the structure without destroying the entire spheroid, we reconstructed its 3D morphology using transparent processing technology and the Z-stack function of confocal microscopy. Additionally, a nano antibody-based 3D immunostaining assay was used to analyze the proliferation and differentiation characteristics of these cells. It found that M2-type macrophages were capable of promoting the differentiation of 3T3 fibroblast spheroid. In this study, a novel, inexpensive platform was constructed for developing spheroids, as well as a 3D immunofluorescence method for investigating the macrophage-associated wound healing microenvironment.