Wound healing, fibroblast heterogeneity, and fibrosis

Promoting scarless wound closure utilizing an injectable thermosensitive hydrogel with anti-inflammatory, antioxidant, and scar formation inhibiting properties

Skin trauma, surgery, or burns can result in non-functional scar tissue, causing significant physiological and psychological harm to patients. Therefore, there is an urgent need for a treatment strategy that promotes rapid wound healing and suppresses scar formation. In this study, we developed a facile and injectable composite hydrogel system (PF-127@ERD) loaded with eriodictyol, which exhibits efficient sustained release of the scar-inhibiting compound at different stages of wound healing to facilitate rapid and scarless closure. Our findings revealed that PF-127@ERD not only stops bleeding and reduces local oxidative stress damage in skin wounds but also regulates the inflammatory microenvironment by inhibiting the expression of relevant inflammatory factors while promoting fibroblast migration. Furthermore, PF-127@ERD inhibits excessive collagen deposition and regulates the expression of genes associated with scar formation, thereby promoting scar-free wound healing. In a rat model of full-layer skin defects, skin wound tissue treated with PF-127@ERD healed faster, exhibited more orderly collagen alignment, and showed reduced scar tissue formation compared to other groups. This process may be due to its inhibition of ferroptosis-related pathways. Therefore, this straightforward hydrogel system based on the skin repair stage (PF-127@ERD) holds great potential for scarless wound healing.

Fibroblasts fluctuating between mesenchyme and epithelium are involved in hair follicle mesenchyme development

The transition between the mesenchyme and epithelium contributes to the development of various tissues. During skin development, epithelial-mesenchymal transition in the ectodermal epithelia is involved in the development of the dermal mesenchyme in early embryos. However, the precise roles and functions of epithelial-mesenchymal/mesenchymal-epithelial transition in cutaneous development have not been fully elucidated. In this study, we aimed to elucidate these roles and functions in the neonatal mouse skin. We conducted single-cell RNA sequencing and immunohistochemical analyses to search for Pdgfra-expressing (Pα +) fibroblasts with transition activities to/from Krt5-expressing keratinocytes. We determined that the Pα +/Krt5-lineage (K5 lin+) fibroblasts significantly contributed to developing hair follicle dermal stem cells to generate lower dermal papilla cells and lower dermal sheath cells. In the developing mouse skin, K5 lin + fibroblasts appeared concurrently with hair follicle development and formed outer edge cells in the early dermal papilla on embryonic day 16.5. K5 lin + hair follicle mesenchymal cells were also maintained in aged mouse skin. These results provide insights into the role and function of the transition between the mesenchyme and epithelium in hair follicle development and maintenance.

Hidradenitis Suppurativa Tunnels: Unveiling a Unique Disease Entity

Hidradenitis suppurativa tunnel structures lined with epithelium within the dermis are unique features of advanced disease stages that significantly impair patients' QOL. The presence of hidradenitis suppurativa tunnels is associated with a decreased likelihood of achieving a clinical response, even when receiving biological therapy. The cellular and molecular mechanisms underlying tunnel formation and pathology are only partially understood, which hampers the development of more effective targeted therapies. Tunnels create a unique microenvironment that drives a vicious cycle of hidradenitis suppurativa inflammation, with tunnel keratinocytes exhibiting an activated phenotype characterized by distinct gene expression signatures. In this review, we summarize the current literature and discuss aspects of the pathophysiology of tunnels, including the role of hair follicle epidermal stem cells in tunnel formation, potential role of fibroblast-mediated epithelial-mesenchymal transition, role of dermal papilla fibroblasts, and aberrant proinflammatory repair response contributing to the observed fibrosis and scarring. Finally, tunnel structures are characterized by unique microbial dysbiosis and an overabundance of Gram-negative anaerobes that are not targeted by current therapeutics. In addition to outlining the possible mechanisms of tunnel formation, we provide perspectives on the translation of current knowledge into more effective treatment approaches for patients with hidradenitis suppurativa tunnels.

Dermal fibroblast-derived extracellular matrix (ECM) synergizes with keratinocytes in promoting re-epithelization and scarless healing of skin wounds: Towards optimized skin tissue engineering

Skin serves as the first-order protective barrier against the environment and any significant disruptions in skin integrity must be promptly restored. Despite significant advances in therapeutic strategies, effective management of large chronic skin wounds remains a clinical challenge. Dermal fibroblasts are the primary cell type responsible for remodeling the extracellular matrix (ECM) in wound healing. Here, we investigated whether ECM derived from exogenous fibroblasts, in combination with keratinocytes, promoted scarless cutaneous wound healing. To overcome the limited lifespan of primary dermal fibroblasts, we established reversibly immortalized mouse dermal fibroblasts (imDFs), which were non-tumorigenic, expressed dermal fibroblast markers, and were responsive to TGF-β1 stimulation. The decellularized ECM prepared from both imDFs and primary dermal fibroblasts shared similar expression profiles of extracellular matrix proteins and promoted the proliferation of keratinocyte (iKera) cells. The imDFs-derived ECM solicited no local immune response. While the ECM and to a lesser extent imDFs enhanced skin wound healing with excessive fibrosis, a combination of imDFs-derived ECM and iKera cells effectively promoted the re-epithelization and scarless healing of full-thickness skin wounds. These findings strongly suggest that dermal fibroblast-derived ECM, not fibroblasts themselves, may synergize with keratinocytes in regulating scarless healing and re-epithelialization of skin wounds. Given its low immunogenic nature, imDFs-derived ECM should be a valuable resource of skin-specific biomaterial for wound healing and skin tissue engineering.

Biological solutions activated by cold plasma at atmospheric pressure: A new therapeutic approach for skin wound healing

Chronic wounds are a major public health problem, and nearly 35 % of them do not heal with conventional treatments. The direct application of cold plasmas at atmospheric pressure, partially ionized gases, is an emerging technology with a range of potential biomedical applications, including the improvement of wound healing. A new method that is easier to implement has been developed: the use of biological solutions exposed to cold plasmas at atmospheric pressure, known as plasma-activated media (PAM). Numerous preclinical studies and in vitro models indicate that PAM treatments facilitate wound healing by promoting the migration of cell types such as keratinocytes, fibroblasts and mesenchymal stem/stromal cells, stimulating angiogenesis, and inhibiting bacterial proliferation, all of which are critical to this vital process. PAM treatments modulate the inflammatory response, induce the expression of growth factors and matrix metalloproteinases, reduce cellular adhesion, promote cytoskeletal modifications and activate several biochemical pathways involved in the wound healing process, possibly through the action of plasma-generated reactive oxygen and nitrogen species. Some studies have shown that PAM may have applications in the treatment of other skin conditions either by reducing the production of pro-inflammatory cytokines or by inducing apoptosis of tumor cells. PAM treatments therefore represent a promising new therapy for the management of dermatological conditions, particularly for chronic skin and mucosal wounds.

ACKR3 in Skin Homeostasis, an Overlooked Player in the CXCR4/CXCL12 Axis

CXCL12 and its receptor CXCR4 emerge as critical regulators within the intricate network of processes ensuring skin homeostasis. In this review, we discuss their spatial distribution and function in steady-state skin; delve into their role in acute wound healing, with emphasis on fibrotic and regenerative responses; and explore their relevance in skin responses to commensals and pathogens. Given the lack of knowledge surrounding ACKR3, the atypical receptor of CXCL12, we speculate whether and how it might be involved in the processes mentioned earlier. Is ACKR3 the (a)typical friend who enjoys missing the party, or do we need to take a closer look?

Targeting PIM1 by Bruceine D attenuates skin fibrosis via myofibroblast ferroptosis

Skin pan-fibrosis diseases-such as hypertrophic scar (HS), keloid scar (KS), and systemic sclerosis (SSc)-pose significant threats to patients' health and quality of life. In this study, the authors conducted both in vivo and in vitro experiments and discovered that the serine/threonine kinase PIM1 is upregulated in the myofibroblasts of human HS, KS, and SSc tissues, as well as in various animal models of skin fibrosis. Overexpression of PIM1 enhanced the profibrotic phenotypes of human hypertrophic scar fibroblasts (HSFs), which serve as key effector cells in the pathogenesis of skin pan-fibrosis diseases. Through high-throughput screening and subsequent laboratory assays, we identified the small molecule Bruceine D (BD) as a direct binder of PIM1. BD promoted ferroptosis in HSFs by selectively suppressing the PIM1-KEAP1-NRF2 pathway through augmented degradation of PIM1. In various in vivo models-including a hypertrophic scar mouse model, a rabbit ear hypertrophic scar model, and a bleomycin (BLM)-induced skin fibrosis mouse model-BD effectively attenuated fibrotic phenotypes. Collectively, these findings demonstrate that PIM1 serves as a common biomarker and therapeutic target for skin pan-fibrosis diseases. BD mitigates skin fibrosis by activating ferroptosis via PIM1 inhibition, highlighting its great translational potential and high promise to be developed to a clinical drug in treating these conditions, especially those with abnormally elevated PIM1 expression.

Anisotropic structure of nanofiber hydrogel accelerates diabetic wound healing via triadic synergy of immune-angiogenic-neurogenic microenvironments

Wound healing in chronic diabetic patients remains challenging due to the multiple types of cellular dysfunction and the impairment of multidimensional microenvironments. The physical signals of structural anisotropy offer significant potential for orchestrating multicellular regulation through physical contact and cellular mechanosensing pathways, irrespective of cell type. In this study, we developed a highly oriented anisotropic nanofiber hydrogel designed to provide directional guidance for cellular extension and cytoskeletal organization, thereby achieving pronounced multicellular modulation, including shape-induced polarization of macrophages, morphogenetic maturation of Schwann cells, oriented extracellular matrix (ECM) deposition by fibroblasts, and enhanced vascularization by endothelial cells. Additionally, we incorporated a VEGF-mimicking peptide to further reinforce angiogenesis, a pivotal phase that interlocks with immune regulation, neurogenesis, and tissue regeneration, ultimately contributing to optimized inter-microenvironmental crosstalk. In vivo studies validated that the anisotropic bioactive nanofiber hydrogel effectively accelerated diabetic wound healing by harnessing the triadic synergy of the immune-angiogenic-neurogenic microenvironments. Our findings highlight the promising potential of combining physical and bioactive signals for the modulation of various cell types and the refinement of the multidimensional microenvironment, offering a novel strategy for diabetic wound healing.

Single-nucleus RNA sequencing and spatial transcriptomics reveal the mechanism by which Xiaozhiling injection treats internal hemorrhoids

BACKGROUND

Hemorrhoids, a prevalent chronic condition globally, significantly impact patients' quality of life. While various surgical interventions, such as external stripping and internal ligation, procedure for prolapse and hemorrhoids, and tissue selecting technique, are employed for treatment, they are often associated with postoperative complications, including unsatisfactory defecation, bleeding, and anal stenosis. In contrast, Xiaozhiling injection, a traditional Chinese medicine-based therapy, has emerged as a minimally invasive and effective alternative for internal hemorrhoids. This treatment offers distinct advantages, such as reduced dietary restrictions, broad applicability, and minimal induction of systemic inflammatory responses. Additionally, Xiaozhiling injection effectively eliminates hemorrhoid nuclei, prevents local tissue necrosis, preserves anal cushion integrity, and mitigates postoperative complications, including bleeding and prolapse. Despite its clinical efficacy, the molecular mechanisms underlying its therapeutic effects remain poorly understood, warranting further investigation.

AIM

To investigate the molecular mechanism underlying the therapeutic effect of Xiaozhiling injection in the treatment of internal hemorrhoids.

METHODS

An internal hemorrhoid model was established in rats, and the rats were randomly divided into a modeling group [control group (CK group)] and a treatment group. One week after injection, Stereo-seq and electron microscopy were used to study the changes in gene expression and subcellular structures in fibroblasts.

RESULTS

Single-cell sequencing revealed differences in the expression and transcript levels of the genes collagen 3 alpha 1, decorin, and actin alpha 2 in fibroblasts between the CK group and the treatment group. Spatial transcriptome analysis revealed that genes of the sphingosine kinase 1 (Sphk1)/sphingosine-1-phosphate (S1P) pathway spatially overlapped with key genes of the transforming growth factor beta 1 pathway, namely, Sphk1, S1P receptor, and transforming growth factor beta 1, in the treatment group. The proportion of fibroblasts was lower in the treatment group than in the CK group, and Xiaozhiling treatment had a significant effect on the proportion of fibroblasts in hemorrhoidal tissue. Immunohistochemistry revealed a significant increase in the expression of a fibroblast marker. Electron microscopy showed that the endoplasmic reticulum of fibroblasts contained a large amount of glycogen, indicating cell activation. Fibroblast activation and the expression of key genes of the Sphk1-S1P pathway could be observed at the injection site, suggesting that after Xiaozhiling intervention, the Sphk1-S1P pathway could be activated to promote fibrosis.

CONCLUSION

Xiaozhiling injection exerts its therapeutic effects on internal hemorrhoids by promoting collagen synthesis and secretion in fibroblasts. After Xiaozhiling intervention, the Sphk1-S1P pathway can be activated to promote fibrosis.

10-Methoxy-leonurine accelerated wound healing through ErbB4/PI3K-AKT pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Leonurusjaponicus Houtt., commonly known as motherwort, has been used in traditional Chinese medicine to treat trauma and wound infections historically. However, the main compounds responsible for promoting wound healing need to be identified and explained fully.

AIM OF THE STUDY

To investigate the wound healing effect of 10-methoxy-leonurine (MN) and explore its mechanism.

MATERIALS AND METHODS

Following the UHPLC/Q-TOF-MS analysis of L. japonicus, the phytochemical isolation was carried out, and then the effect of isolated compounds in promoting the proliferation of human skin fibroblasts (HSF) was screened. Additionally, scratch and 5-ethynyl-2'-deoxyuridine assay in HSF were further adopted to support the effects of MN in vitro. A rat model with full-thickness skin wounds was used to verify in vivo by hematoxylin and eosin staining, Masson's trichrome and immunohistochemistry. Furthermore, network pharmacology and molecular docking were performed to predict the potential pathway, which were subsequently validated by cell cycle and RT-qPCR.

RESULTS

A total 11 compounds were isolated, in which MN exhibited the most significant bioactivity in promoting HSF proliferation and migration. Moreover, the wound healing rates in low (10 μg/mL) and high dose (50 μg/mL) of MN groups reached 93.9 % and 94.5 %, respectively, which was better than basic fibroblast growth factor (bFGF) 89.4 %. Additionally, the epithelial thickness, collagen Ⅰ deposition and α-smooth muscle actin expression were enhanced and the proportion of HSF cells in the S phase of the cell cycle was increased. Network pharmacological and molecular docking analysis suggested ErbB pathway was involved in the regulation of wound healing by MN, which was further supported by the up-regulation of Erbb4, Stat5, Pi3k, Akt and mTOR mRNA levels.

CONCLUSION

MN showed potent effect on wound healing by regulating ErbB4/PI3K-AKT pathway, even better than bFGF.

Effects of embryonic origin, tissue cues and pathological signals on fibroblast diversity in humans

Fibroblasts, once perceived as a uniform cell type, are now recognized as a mosaic of distinct populations with specialized roles in tissue homeostasis and pathology. Here we provide a global overview of the expanding compendium of fibroblast cell types and states, their diverse lineage origins and multifaceted functions across various human organs. By integrating insights from developmental biology, lineage tracing and single-cell technologies, we highlight the complex nature of fibroblasts. We delve into their origination from embryonic mesenchyme and tissue-resident populations, elucidating lineage-specific behaviours in response to physiological cues. Furthermore, we highlight the pivotal role of fibroblasts in orchestrating tissue repair, connective tissue remodelling and immune modulation across diverse pathologies. This knowledge is essential to develop novel fibroblast-targeted therapies to restore steady-state fibroblast function and advance regenerative medicine strategies across multiple diseases.

Wound Tissue Regeneration by Microfluidic Generated Fibroblast Cell/CuO Nanosheet-Loaded Alginate Hydrogel on an Excisional Full-Thickness Rat Model

Chronic ulcers present numerous challenges in treatment such as prolonged inflammation, infections resistant to drugs, and the formation of scars. In this research, we developed a calcium ion (Ca2+) cross-linked alginate (Alg) hydrogel loaded with CuO nanosheet/fibroblast cells via a microfluidic system with substantial efficiency in accelerating healing and preventing infection. Initially, the soft lithography method was utilized to fabricate the microfluidic system, which was employed to produce alginate hydrogel incorporating nanosheets of copper oxide (CuO) and MEF cells. The properties of hydrogel and copper oxide nanosheets were analyzed by using FE-SEM, EDS/EDX, and elemental mapping to determine their physicochemical characteristics. The viability of mouse embryonic fibroblast cells (MEF) in alginate-CuO hydrogel was explored through cell viability assay, and the antibacterial properties were also studied using colony-forming assay. The healing abilities of the hydrogel were investigated using an excisional, full-thickness wound rat model. Our results revealed proper antimicrobial and angiogenic properties with slight cytotoxicity for CuO nanosheets at a concentration of 25 μg/mL. The alginate-CuO-cell-treated group exhibited a faster wound contraction and healing among all treatments. The results of the in vivo assay along with histology and gene expression indicate a synergistic cooperation between MEF and CuO, leading to enhanced re-epithelialization, angiogenesis, and matrix remodeling. In this research, a therapeutic hydrogel with qualities like microbicidal, angiogenic, immune system modulation, and promotion of ECM and epithelium regeneration, resulting in faster healing, was developed. Moreover, there was a synergic impact noticed between CuO nanosheets and MEF cells as well as improved formation of blood vessels and collagen accumulation. In conclusion, this biocompatible hydrogel offers a promising strategy for effective wound healing without the need for invasive procedures.

Recent advances in structural and functional design of electrospun nanofibers for wound healing

The global prevalence of acute and chronic wounds has surged, escalating healthcare burdens and necessitating advanced therapeutic strategies for effective wound management. Electrospun nanofibers have emerged as promising biomimetic platforms for tissue engineering and drug delivery, due to their structural resemblance to the native extracellular matrix (ECM), high porosity, and tunable surface-to-volume ratio. Recent advances in structural design have expanded their applications from conventional two-dimensional (2D) wound dressings to multifunctional three-dimensional (3D) architectures, enabling enhanced mechanical adaptability, bioactive molecule loading, and spatiotemporal control over wound microenvironments. These innovations leverage nanofibers' customizable topography and composition to recapitulate critical ECM cues, thereby fostering cell proliferation, angiogenesis, and immunomodulation during tissue regeneration. This review systematically evaluates cutting-edge strategies focusing on optimizing 2D arrangements and the structural design of multilayered and functionally patterned 3D electrospun nanofibers in wound healing applications. We further present the advantages and limitations of various nanofiber structures, along with the key challenges and future directions for advancing electrospun nanofibers specifically designed for enhanced wound healing.

Forskolin-loaded carboxymethyl chitosan and silk nonofiber hydrogels composite scaffolds improve skin regeneration

Hydrogel is a kind of carrier of powerful therapeutic bioactive molecules. Here, carboxymethyl chitosan-silk nanofiber (CCSF) composite hydrogels loaded with a small molecule compound, Forskolin, were prepared to achieve sustained release of the small molecule drug for promoting wound healing. In vitro, investigations confirmed that the innovative composite dressing is non-toxic and cyto-compatible. Specifically, it can encourage the proliferation of human umbilical vein endothelial cells (HUVECs) and mouse dermis fibroblasts, and inhibit the accumulation of intracellular reactive oxygen species (ROS) in the cells. The capacity of cell migration in myofibroblasts was restrained, also implying less scarring in vivo. Skin wound regeneration results showed that the Forskolin-loaded compound hydrogel accelerated wound closure, enhanced neovascularization, and promoted hair follicle regeneration. The multiple-material delivery system shows a promising application in skin wound repair.

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.

Biomimetic Synthesis of Nanomachine Inspired from Neutrophil Extracellular Traps for Multimodal Antibacterial Application

Bacterial infections, especially drug-resistant bacterial infections, are causing increasing harm in clinical practice, and there is an urgent need to develop effective antimicrobial materials. Biomimetic DNA nanomachines have attracted much attention due to their flexible design, precise control, and high biocompatibility, but their use for bacterial inhibition has not been reported. Neutrophil extracellular traps (NETs), a network structure released by neutrophils with good bactericidal function, can be used as a superior biomimetic object for the construction of functional bacterial inhibition materials. In this study, Y-shaped DNA was polymerized using magnesium ions to develop reticulated DNA structures, which were used as templates to synthesize copper nanoclusters, leading to the construction of compositionally well-defined and simple reticulated DNA nanomachines. The nanomachine had a three-dimensional, reticular structure similar to that of NETs and especially had excellent antibacterial activity. More importantly, the NETs-imitated nanomachine had a multimodal bacterial inhibition mechanism. The nanomachine could target and localize around the bacteria and eliminate the biofilm, and then the DNA network structure effectively trapped and aggregated the bacteria and caused damage to the bacterial morphology and membrane structure; at the same time, the reticulated DNA nanomachine could also damage the bacterial membrane, causing the degradation and leakage of the proteins and the cellular contents and breakage of the DNA structure, ultimately causing irreversible inhibition of the bacteria. Importantly, the developed nanomachines with high biocompatibility could be used as antimicrobial biomaterials for the efficient treatment and healing of skin wounds infected with bacteria. This study develops a biomimetic DNA nanomachine that can be an excellent antibacterial biomaterial, which expands the application of DNA nanomachine in bacteriostatic and therapeutic fields; it is also an improved biomimetic NETs biomaterial, which brings distinctive design sources for biomimetic materials.

Pan-immune-inflammatory value and systemic immune-inflammatory index in relation to osteoradionecrosis of the jaws: a single institutional experience over 15 years

Osteoradionecrosis of the jaws (ORNJ) is a pernicious complication of radiation therapy that significantly affects the quality of life of patients with head and neck cancer. The present study aims to investigate the risk factors for the clinical prognosis of ORNJ in the same scenario. A cross-sectional study was designed and implemented in a tertiary teaching hospital from January 2005 to December 2020. A total of 106 patients were divided into normal wound-healing group (n = 79) and delayed wound-healing group (n = 27) according to two different prognosis. The risk factors associated with the prognosis in patients with ORNJ were comparatively analyzed via performing one-way and multifactorial logistic analyses. The majority of the study cohort (n = 59, 55.7%) was found to be characterized with Glanzmann and Gratz grade 2 and followed up for a median of 38.6 months. Diabetes mellitus (p = 0.045), Charlson comorbidity index (p = 0.042), American Society of Anesthesiologists score (p < 0.001), primary tumor site (p = 0.012), T stage (p = 0.008), ORNJ grade at initial diagnosis (p < 0.001), pan-immune-inflammatory value and systemic immune-inflammatory index at initial radiotherapy (p = 0.01 and p < 0.001 respectively) were detected as risk factors associated with poor prognosis in patients with ORNJ. We conclude that there are abundant risk factors for poor prognosis in these patients, and it is important to be evaluated before irradiation so that suitable post-radiated treatments can be given.

SHP099-containing multi-targeting hydrogel promotes rapid skin reconstruction through modulating a variety of cells

Introduction

Adult wound scarring result in functional skin deficits. However, the development of effective measures to modulate the entire wound healing to encourage the skin function reconstruction is still a clinical challenge, as multiple cells are involved in wound healing hierarchically. Hydrogel scaffolds with long-lasting local release provide new insights into the clinical relevance of entire wound healing.

Methods

Herein, a multi-targeting hydrogel loaded with SHP099 (Gel-SHP) is designed to modulate multiple cells during wound repair.

Results

Our results show that Gel-SHP promotes rapid reconstruction of wound skin by modulating macrophages in the inflammatory stage, fibroblasts in the regeneration stage and smooth muscle cells in the remodelling stage. Gel-SHP could increase M2 macrophage differentiation and remodel the dermal shell of hair follicles through in situ release. Moreover, Gel-SHP may modulate myofibroblasts to promote wound contraction through SHP099-scaffold synergistic interactions.

Discussion

Our results provide new insights into the design of functional hydrogels for tissue regeneration applications. Gel-SHP as a promising tool could provide new clues and new research paradigms for future studies and understanding of the wound healing process and dermal shell formation.

Dynamic substrate topographies drive actin- and vimentin-mediated nuclear mechanoprotection events in human fibroblasts

BACKGROUND

Dynamic physical changes in the extracellular environment of living tissues present a mechanical challenge for resident cells that can lead to damage to the nucleus, genome, and DNA. Recent studies have started to uncover nuclear mechanoprotection mechanisms that prevent excessive mechanical deformations of the nucleus. Here, we hypothesized that dynamic topographical changes in the cellular environment can be mechanically transmitted to the nucleus and trigger nuclear mechanoprotection events. We tested this using a photoresponsive hydrogel whose surface topography can be reversibly changed on demand upon light illumination, allowing us to subject cells to recurring microscale topographical changes.

RESULTS

With each recurring topographical change, fibroblasts were found to increasingly compact and relocate their nuclei away from the dynamic regions of the hydrogel. These cell-scale reorganization events were accompanied by an increase of global histone acetylation and decreased methylation in cells on the dynamic topographies, resulting in a minimization of DNA strand breakage. We further found that these nuclear mechanoprotection events were mediated by both vimentin intermediate filaments and the actin cytoskeleton.

CONCLUSIONS

Together, these data reveal that fibroblasts actively protect their nuclei in the presence of dynamic topographical changes through cytoskeleton-mediated mechanisms. Broadly, these results stress the importance of gaining a deeper fundamental understanding of the cellular mechanoresponse under dynamically changing conditions.

Overexpression of miR-192 in fibroblasts accelerates wound healing in diabetic rats: research article

BACKGROUND

Diabetic foot ulcer (DFU) is a severe diabetic complication. Transplantation of skin substitutes, stem cells, and platelet-rich plasma (PRP) treatments are promising tools to promote ulcer healing in diabetes. An important aspect of the remodeling phase of wound healing is collagen deposition. miR-192 increases the expression of COL1A2 by specifically targeting Smad-interacting protein 1 (SIP1). This study was designed to investigate the impact of combined treatment with platelet-rich plasma and fibroblast cells expressing miR-192 on the healing process of wounds using an experimental diabetic animal model.

METHODS

After transfection of HDF cells and induction of increased miR-192 expression, relative changes in COL1A2 gene expression were determined by the RT-PCR method. Rats were randomly divided into 6 groups: non-diabetic control group, diabetic control, backbone, PRP, miR-192, and PRP + miR-192 groups. Diabetes was induced in male Wistar rats of all treated groups except non-diabetic control through a 21-day high-fat diet and an intraperitoneal injection of 40 mg/kg streptozotocin. A 10-mm skin biopsy punch was used to create two full-thickness wounds on the dorsal part of the upper body in all six groups of animals. Hematoxylin-eosin and Mason's trichrome staining were used to evaluate the wounds and analyze histological changes.

RESULTS

The overexpression of miR-192 in HDF cells resulted in a significant increase in COL1A2 gene expression, which was 15.77-fold higher than the control group. PRP and pLenti-III-miR-192-GFP-expressing cells significantly increased wound closure rates, granulation tissue area, and collagen fiber density in rats, according to a histological examination.

CONCLUSION

The combined use of PRP and HDFs expressing pLenti-III-miR-192-GFP speeds up the healing of wounds by increasing collagen expression, demonstrating the efficacy of this approach in improving wound healing results.

Integration of Flow Cytometry and Single-Cell RNA Sequencing Analysis to Explore the Fibroblast Subpopulations in Keloid that Correlate with Recurrence

Objective: Fibroblasts (FBs) are the cytological basis of keloid (KD) formation. This study aimed to identify the key pathogenic target cell subpopulation involved in KD recurrence. Approach: Single-cell RNA sequencing data were retrieved from public databases, revealing distinct gene expression patterns in FB subpopulations. Flow cytometry (FCM) was used to identify the surface molecular phenotypes of FBs that affect KD recurrence. Simultaneously, logistic regression analysis was performed to assess the predictive value of changes in FB subpopulation percentages for clinical KD recurrence. Results: The percentage of keloid fibroblasts was significantly greater than that in normal tissues. Through further clustering analysis of the FB population, we obtained four subpopulations, FB1-FB4, in which the percentages of FB1 subpopulation were increased, and functional enrichment analysis suggested that the FB1 subpopulation may play a greater role in extracellular matrix collagen oversynthesis in KD. In addition, the gene expression of CD26 (DPP4), CD117 (c-KIT), and CD34 in the FB1 subpopulation was significantly higher than that in FB2-4 subpopulations. Moreover, the percentage of CD26+/CD117+/CD34+ cell subpopulations in the FCM data of patients with KD recurrence was significantly increased. Regression analysis confirmed that the CD26+/CD117+/CD34+ FB subpopulation was a risk factor for relapse. Innovation: We demonstrated that the molecular phenotypic and functional heterogeneity of FBs influences KD recurrence. Conclusion: We identified key pathogenic FB subpopulations that may affect KD development, which can be used as potential markers to predict recurrence and provide potential target cell populations for future clinical treatment.

Facile Fabrication of Injectable Multifunctional Hydrogels Based on Gallium-Polyphenol Networks with Superior Antibacterial Activity for Promoting Infected Wound Healing

Multifunctional hydrogels hold significant promise for promoting the healing of infected wounds but often fall short in inhibiting antibiotic-resistant pathogens, and their clinical translation is limited by complex preparation processes and high costs. In this study, a multifunctional hydrogel is developed by combining metal-phenolic networks (MPNs) formed by tannic acid (TA) and gallium ions (Ga3⁺) with chitosan (CS) through a simple one-step method. The resulting CS-TA-Ga3⁺ (CTG) hydrogel is cost-effective and exhibits desirable properties, including injectability, self-healing, pH responsiveness, hemostasis, antioxidant, anti-inflammatory, and antibacterial activities. Importantly, the CTG hydrogels are effective against antibiotic-resistant pathogens due to the unique antibacterial mechanism of Ga3⁺. In vivo studies demonstrate that the CTG hydrogel promotes follicle formation and collagen deposition, accelerating the healing of infected wounds by inhibiting blood loss, suppressing bacterial growth, and modulating the inflammatory microenvironment. These findings highlight the CTG hydrogel's potential as an advanced and translational dressing for enhancing the healing of infected wounds.

Eosinophilic esophagitis drives tissue fibroblast regenerative programs toward pathologic dysfunction

BACKGROUND

Pathologic tissue remodeling with scarring and tissue rigidity has been demonstrated in inflammatory, autoimmune, and allergic diseases. Eosinophilic esophagitis (EoE) is an allergic disease that is diagnosed and managed by repeated biopsy procurement, allowing an understanding of tissue fibroblast dysfunction. While EoE-associated tissue remodeling causes clinical dysphagia, food impactions, esophageal rigidity, and strictures, molecular mechanisms driving these complications remain under investigation.

OBJECTIVE

We hypothesized that chronic EoE inflammation induces pathogenic fibroblasts with dysfunctional tissue regeneration and motility.

METHODS

We used single-cell RNA sequencing, fluorescence-activated cell sorting analysis, and fibroblast differentiation and migration assays to decipher the induced and retained pathogenic dysfunctions in EoE versus healthy esophageal fibroblasts.

RESULTS

Differentiation assays demonstrated that active EoE fibroblasts retain regenerative programs for rigid cells such as chondrocytes (P < .05) but lose healthy fibroblast capacity for soft cells such as adipocytes (P < .01), which was reflected in biopsy sample immunostaining (P < .01). EoE, but not healthy, fibroblasts show proinflammatory and prorigidity transcriptional programs on single-cell RNA sequencing. In vivo, regenerative fibroblasts reside in perivascular regions and near the epithelial junction, and during EoE, they have significantly increased migration (P < .01). Flow analysis and functional assays demonstrated that regenerative EoE fibroblasts have decreased surface CD73 expression and activity (both P < .05) compared to healthy controls, indicating aberrant adenosine triphosphate handling. EoE fibroblast dysfunctions were induced in healthy fibroblasts by reducing CD73 activity and rescued in EoE using adenosine repletion.

CONCLUSION

A normalization of perturbed extracellular adenosine triphosphate handling and CD73 could improve pathogenic fibroblast dysfunction and tissue regeneration in type 2 inflammatory diseases.

Osteosarcoma Exosome Priming of Primary Human Lung Fibroblasts Induces an Immune Modulatory and Protumorigenic Phenotype

SIGNIFICANCE

These findings provide a critical first step in characterizing the capacity of OS-derived exosomes to reprogram primary LFs toward a tumor-promoting inflammatory phenotype in vitro, offering novel molecular targets for the modulation of fibroblasts in the lung microenvironment as potential therapeutic strategies to prevent OS metastasis.

Species differences in glycerol-3-phosphate metabolism reveals trade-offs between metabolic adaptations and cell proliferation

The temperate climate-adapted brown hare (Lepus europaeus) and the cold-adapted mountain hare (Lepus timidus) are closely related and interfertile species. However, their skin fibroblasts display distinct gene expression profiles related to fundamental cellular processes. This indicates important metabolic divergence between the two species. Through targeted metabolomics and metabolite tracing, we identified species-specific variations in glycerol 3-phosphate (G3P) metabolism. G3P is a key metabolite of the G3P shuttle, which transfers reducing equivalents from cytosolic NADH to the mitochondrial electron transport chain (ETC), consequently regulating glycolysis, lipid metabolism, and mitochondrial bioenergetics. Alterations in G3P metabolism have been implicated in multiple human pathologies including cancer and diabetes. We observed that mountain hare mitochondria exhibit elevated G3P shuttle activity, alongside increased membrane potential and decreased mitochondrial temperature. Silencing mitochondrial G3P dehydrogenase (GPD2), which couples the conversion of G3P to the ETC, uncovered its species-specific role in controlling mitochondrial membrane potential and highlighted its involvement in skin fibroblast thermogenesis. Unexpectedly, GPD2 silencing enhanced wound healing and cell proliferation rates in a species-specific manner. Our study underscores the pivotal role of the G3P shuttle in mediating physiological, bioenergetic, and metabolic divergence between these hare species.

Single-nucleus RNA sequencing decodes abnormal cell-collagen communication in a sheep endometrial fibrosis model

Endometrial fibrosis in sheep reduces reproductive performance with elusive therapeutic targets. The fibrotic endometrium is a complex ecosystem with heterogeneous cells and their interactions. The molecular characterization of key cells and the mechanisms of these interactions are unclear. To uncover the key molecular features of sheep endometrial fibrosis tissue, we used single-nucleus RNA sequencing to profile the transcriptional characterization of sheep endometrial cells from both normal and fibrotic tissues, aiming to clarify the mechanisms of fibrosis development. Histomorphological analysis revealed significant collagen deposition in fibrotic endometrial tissue. The transcription atlas of sheep endometrial cells was created, identifying eight main endometrial cell types. Key findings include the abnormal expression of collagen-related genes in fibrotic cells and the identification of endothelial cells and fibroblasts as major contributors to fibrogenesis with aberrant receptor-ligand interactions involving collagen-related genes. Fibroblasts had a tendency to differentiate into myofibroblasts in fibroblast-mediated fibrosis progression. In vitro experiments demonstrated the role of fibroblasts in fibroblast activation through the PERK/eIF2α/CHOP stress pathway. Additionally, fibrosis disturbs the immune microenvironment. This study highlights that high collagen gene expression in injured endometrial cells leads to abnormal tissue repair and fibrosis, offering valuable insights for understanding endometrial fibrosis at the single-cell level.

Increasing collagen synthesis in fibroblasts: The roles of PCL microspheres and the SAMD11-PLOD1 axis in skin rejuvenation

The degradation of extracellular matrix proteins such as collagen and elastin with aging leads to skin sagging. Polycaprolactone (PCL) microspheres are used as facial fillers because of their ability to provide volume, biodegradability, and collagen-stimulating properties. The direct biological effects of PCL microspheres on fibroblasts, particularly in stimulating sustained collagen production, require further investigation. We detected the safety and effect of PCL microspheres on human fibroblasts and investigated new collagen synthesis and the thickness of C57BL/6 mouse skin. Through an RNA-seq analysis of differentially expressed genes, we identified a key regulator of collagen production in PCL-stimulated fibroblasts. Our research revealed that PCL microspheres are safe for human fibroblasts, promoting their proliferation and increasing new collagen synthesis and skin thickness. We identified sterile alpha motif domain containing 11 (SAMD11) as a key regulator of collagen production in PCLstimulated fibroblasts through an RNA-seq analysis. By increasing SAMD11 expression, PCL microspheres increase collagen synthesis and rejuvenate skin through the upregulation of procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 (PLOD1). This study elucidates the mechanism by which SAMD11 regulates the effects of PCL microspheres as collagen stimulants for skin rejuvenation, providing a foundation for the future development and refinement of similar materials.

PU.1/Spi1 exacerbates ischemia-reperfusion induced acute kidney injury via upregulating Gata2 and promoting fibroblast activation

Previous studies on acute kidney injury (AKI) have predominantly focused on renal tubular cells, while the specific role of fibroblasts has been largely neglected. Recent evidence shows that PU.1/Spi1, a transcription factor, is an important modulator of fibroblast activation, whereas pharmacological and genetic silencing of PU.1/Spi1 disrupts the fibrotic network and reprograms activated fibroblasts into quiescent fibroblasts. In this study we investigated whether and how PU.1/Spi1 regulated renal fibroblast activation during AKI. An AKI model was established in male mice by clamping bilateral renal arteries for 30 min. Mice were sacrificed and blood and kidney samples were collected 48 h after the surgery. We showed that the expression level of PU.1/Spi1 was significantly upregulated in ischemia/reperfusion (I/R)-induced AKI and PU.1/Spi1 was specifically localized in fibroblasts. Meanwhile, we observed that a massive activation of fibroblasts occurred at the early stage of AKI. PU.1/Spi1 knockout significantly attenuated the activation of fibroblasts along with the decreased release of inflammatory factors and tubular injury. Bioinformatic analysis revealed that GATA binding protein 2 (Gata2), an evolutionarily conserved gene, might be a downstream target gene of PU.1/Spi1. In primary cultured mouse kidney fibroblasts subjected to hypoxia/reoxygenation (H/R), the expression levels of PU.1/Spi1, Gata2 and α-SMA were significantly upregulated. Activated fibroblasts exhibited elevated proliferative capacity, evidenced by upregulated proliferating cell nuclear antigen (PCNA) and cell cycle proteins such as cyclin B1 and cyclin D3. The secretion of inflammatory factors was increased in the activated fibroblasts. Conditioned medium from H/R-treated fibroblasts induced tubular cell injury and increased apoptosis. Using chromatin immunoprecipitation and promoter-luciferase assays, we demonstrated that PU.1/Spi1 was able to bind to the promoter region of Gata2 and enhanced its transcription. Our results show that interstitial fibroblasts are activated at the early stage of I/R-induced AKI and involved in renal injury. Upregulated PU.1/Spi1 stimulates fibroblast activation by upregulating its downstream gene Gata2. Inhibiting the activation of fibroblasts may have a beneficial effect on AKI.

Crosstalk Signaling Between the Epithelial and Non-Epithelial Compartments of the Mouse Inner Ear

PURPOSE

The otolith organs of the inner ear consist of the utricle and saccule that detect linear acceleration. These organs rely on mechanosensitive hair cells for transduction of signals to the central nervous system. In the murine utricle, about half of the hair cells are born during the first postnatal week. Here, we wanted to explore the role and interaction of the non-epithelial mesenchymal cells with the sensory epithelium and provide a resource for the auditory neurosciences community.

METHODS

We utilized full-length Smart-seq2 single-cell RNA sequencing at postnatal days 4 and 6 along with a host of computational methods to infer interactions between the epithelial and non-epithelial compartments of the mouse utricle. We validated these findings using a combination of immunohistochemistry and quantitative multiplex in situ hybridization.

RESULTS

We report diverse cell-cell crosstalk among the 12 annotated cell populations (n = 955 cells) in the developing neonatal mouse utricle, including epithelial and non-epithelial cellular signaling. The mesenchymal cells are the dominant signal senders during the postnatal period. Epithelial to mesenchymal signaling, as well as mesenchymal to epithelial signaling, are quantitatively shown through the TGFβ and pleiotrophin pathways.

CONCLUSION

This study highlights the dynamic process of postnatal vestibular organ development that relies not only on epithelial cells, but also on crosstalk between spatial compartments and among different cell groups. We further provide a data-rich resource for the inner ear community.

Histological signatures map anti-fibrotic factors in mouse and human lungs

Fibrosis, the replacement of healthy tissue with collagen-rich matrix, can occur following injury in almost every organ1,2. Mouse lungs follow a stereotyped sequence of fibrogenesis-to-resolution after bleomycin injury3, and we reasoned that profiling post-injury histological stages could uncover pro-fibrotic versus anti-fibrotic features with functional value for human fibrosis. Here we quantified spatiotemporally resolved matrix transformations for integration with multi-omic data. First, we charted stepwise trajectories of matrix aberration versus resolution, derived from a high-dimensional set of histological fibre features, that denoted a reversible transition in uniform-to-disordered histological architecture. Single-cell sequencing along these trajectories identified temporally enriched 'ECM-secreting' (Csmd1-expressing) and 'pro-resolving' (Cd248-expressing) fibroblasts at the respective post-injury stages. Visium-based spatial analysis further suggested divergent matrix architectures and spatial-transcriptional neighbourhoods by fibroblast subtype, identifying distinct fibrotic versus non-fibrotic biomolecular milieu. Critically, pro-resolving fibroblast instillation helped to ameliorate fibrosis in vivo. Furthermore, the fibroblast neighbourhood-associated factors SERPINE2 and PI16 functionally modulated human lung fibrosis ex vivo. Spatial phenotyping of idiopathic pulmonary fibrosis at protein level additionally uncovered analogous fibroblast subtypes and neighbourhoods in human disease. Collectively, these findings establish an atlas of pro- and anti-fibrotic factors that underlie lung matrix architecture and implicate fibroblast-associated biological features in modulating fibrotic progression versus resolution.

Fibrosis: cross-organ biology and pathways to development of innovative drugs

Fibrosis is a pathophysiological mechanism involved in chronic and progressive diseases that results in excessive tissue scarring. Diseases associated with fibrosis include metabolic dysfunction-associated steatohepatitis (MASH), inflammatory bowel diseases (IBDs), chronic kidney disease (CKD), idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc), which are collectively responsible for substantial morbidity and mortality. Although a few drugs with direct antifibrotic activity are approved for pulmonary fibrosis and considerable progress has been made in the understanding of mechanisms of fibrosis, translation of this knowledge into effective therapies continues to be limited and challenging. With the aim of assisting developers of novel antifibrotic drugs, this Review integrates viewpoints of biologists and physician-scientists on core pathways involved in fibrosis across organs, as well as on specific characteristics and approaches to assess therapeutic interventions for fibrotic diseases of the lung, gut, kidney, skin and liver. This discussion is used as a basis to propose strategies to improve the translation of potential antifibrotic therapies.

Inflammatory Transformation of Skin Basal Cells as a Key Driver of Cutaneous Aging

This study comprehensively investigated keratinocyte subpopulation heterogeneity and developmental trajectories during skin aging using single-cell sequencing, transcriptomics, and facial aging-related genome-wide association studies (GWAS) data. We identified three major subpopulations: basal cells (BCs), spinous cells (SCs), and IFI27+ keratinocytes. Single-cell pseudotime analysis revealed that basal cells can differentiate along two distinct paths: toward spinous differentiation or the inflammatory state. With aging, the proportion of IFI27+ cells significantly increased, displaying more active inflammatory and immunomodulatory signals. Through cell-cell communication analysis, we found that the signaling pathways, including NOTCH, PTPR, and PERIOSTIN, exhibited distinct characteristics along different branches. Integration of the GWAS data revealed significant loci on chromosomes 2, 3, 6, and 9 that were spatially correlated with key biological pathways (including antigen processing, oxidative stress, and apoptosis). These findings reveal the complex cellular and molecular mechanisms underlying skin aging, offering potential targets for novel diagnostic approaches and therapeutic interventions.

Esculin promotes skin wound healing in mice and regulates the Wnt/β-catenin signaling pathway

Objective

Previous studies reported that esculin could protect against renal ischemia-reperfusion injury and liver injury, but its mechanism of action in skin wound healing is unclear. The Wnt/β-catenin signaling pathway plays a positive role in the wound healing process. This study aimed to investigate the effects of esculin on the rate and quality of skin wound healing in mice and explore its regulatory role in the Wnt/b-catenin signaling pathway.

Material and Methods

Circular full-thickness skin wounds with a diameter of 8 mm were created on the backs of C57BL/6 mice, which were administered with 20 and 40 mg•kg-1 esculin through gastric lavage. Wound healing was monitored, and samples collected on day 14 were analyzed through hematoxylin-eosin and Masson staining to assess granulation tissue formation and collagen deposition. Immunohistochemistry, immunofluorescence, and Western blot evaluated markers of collagen synthesis, proliferation, angiogenesis, and proteins in the Wnt/b-catenin signaling pathway. National institutes of health/3T3 cells treated with esculin (50 and 200 μM) were analyzed for proliferating cell nuclear antigen (PCNA) expression to assess proliferative activity.

Results

Compared with the model group, the esculin-treated groups exhibited significantly enhanced wound healing (P < 0.05), increased skin epithelial thickness (P < 0.01), and promoted extracellular matrix formation in mice. In addition, esculin significantly raised type I collagen alpha-1 chain and type III collagen alpha-1 chain protein levels (P < 0.05), boosted the expression of the cell proliferation marker PCNA and the vascular marker cluster of differentiation 31 in the dermis (P < 0.05), and upregulated proteins related to the Wnt/b-catenin signaling pathway and increased glycogen synthase kinase 3 beta phosphorylation in skin wound and NIH/3T3 cells (P < 0.05).

Conclusion

Esculin could upregulate and activate the Wnt/b-catenin signaling pathway to promote wound healing.

Lapatinib ameliorates skin fibrosis by inhibiting TGF-β1/Smad and non-Smad signaling pathway

Skin fibrosis, characterized by excessive accumulation of extracellular matrix (ECM) in the dermis, can lead to hypertrophic scars and impaired mobility. The ErbB family of receptor tyrosine kinases, including ErbB1 and ErbB2, plays a crucial role in organ fibrosis, but their specific impact on skin fibrosis is less understood. This study investigated the role of ErbB1 and ErbB2 in skin fibrosis and the therapeutic potential of lapatinib, a dual ErbB1 and ErbB2 tyrosine kinase inhibitor. Using qPCR, cell culture assays, Western blotting, and in vivo models, we found significant upregulation of ErbB1 and ErbB2 in keloid tissues and fibroblasts. Lapatinib treatment resulted in a dose-dependent decrease in ErbB1 and ErbB2 expression, which suppressed the expression of fibroblast activation markers. Our findings suggest that lapatinib may be a promising therapeutic agent for skin fibrosis by targeting ErbB1/ErbB2 and modulating the TGF-β1/Smad2/3/Erk/Akt signalling pathways. These results warrant further clinical investigation into lapatinib for treating skin fibrosis and related conditions.

Redox regulation: mechanisms, biology and therapeutic targets in diseases

Redox signaling acts as a critical mediator in the dynamic interactions between organisms and their external environment, profoundly influencing both the onset and progression of various diseases. Under physiological conditions, oxidative free radicals generated by the mitochondrial oxidative respiratory chain, endoplasmic reticulum, and NADPH oxidases can be effectively neutralized by NRF2-mediated antioxidant responses. These responses elevate the synthesis of superoxide dismutase (SOD), catalase, as well as key molecules like nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione (GSH), thereby maintaining cellular redox homeostasis. Disruption of this finely tuned equilibrium is closely linked to the pathogenesis of a wide range of diseases. Recent advances have broadened our understanding of the molecular mechanisms underpinning this dysregulation, highlighting the pivotal roles of genomic instability, epigenetic modifications, protein degradation, and metabolic reprogramming. These findings provide a foundation for exploring redox regulation as a mechanistic basis for improving therapeutic strategies. While antioxidant-based therapies have shown early promise in conditions where oxidative stress plays a primary pathological role, their efficacy in diseases characterized by complex, multifactorial etiologies remains controversial. A deeper, context-specific understanding of redox signaling, particularly the roles of redox-sensitive proteins, is critical for designing targeted therapies aimed at re-establishing redox balance. Emerging small molecule inhibitors that target specific cysteine residues in redox-sensitive proteins have demonstrated promising preclinical outcomes, setting the stage for forthcoming clinical trials. In this review, we summarize our current understanding of the intricate relationship between oxidative stress and disease pathogenesis and also discuss how these insights can be leveraged to optimize therapeutic strategies in clinical practice.

Ultrasound-Triggered Oxygen Release System for Accelerating Wound Healing of Diabetic Foot Ulcers

Diabetic foot ulcer (DFU) is a common complication of chronic diabetes mellitus. Oxygen plays a critical role in the healing process of DFU wounds by promoting cell migration and neovascularization. However, clinical hyperbaric oxygen (HBO) therapy predominantly uses systemic oxygen administration, posing challenges in inadequate DFU local oxygen penetration and potential ectopic organs oxygen toxicity. To address these challenges, a strategy to encapsulate oxygen with lipid microbubbles (OMBs) and incorporate them into a body temperature-sensitive heparin-pluronic copolymer hydrogel (HP/OMBs) have been developed. HP/OMBs showed high biocompatibility both in vitro and in vivo. After in situ administration, oxygen can be released from HP/OMBs to the local deep site of the DFU wounds under ultrasound (US) triggering. Thus, given its biocompatibility and practicality, the combined action of HP/OMBs and the US has important translational value in accelerating diabetic chronic wound healing.

Current application of tissue-engineered dermal scaffolds mimicking the extracellular matrix microenvironment in wound healing

With the continuous advancement of materials science, cell biology, and biotechnology, tissue engineering has introduced novel solutions to traditional wound healing approaches, particularly demonstrating significant potential in addressing complex or non-healing wounds. One of the key technologies in this field, dermal scaffolds, serve as wound coverage materials that mimic the structural framework of the dermis. They primarily assume the function of extracellular matrix, providing space for cell attachment, migration, and proliferation, thus supporting cellular growth and regulating multiple biological processes in healing. Tissue engineering utilizes combinations of natural or synthetic scaffolds, seeded cells, or growth factors to induce distinct effects in angiogenesis, extracellular matrix deposition, and functional recovery. Therefore, various bioengineered dermal scaffolds hold significant potential for clinical translation in wound healing. This review outlines various extracellular matrix molecules utilized in the development of dermal scaffolds, emphasizes recent progress in cell- and growth factor-modified scaffolds, and discusses the challenges and future perspectives in this evolving field.

Electrospinning strategies targeting fibroblast for wound healing of diabetic foot ulcers

The high incidence and prevalence of diabetic foot ulcers (DFUs) present a substantial clinical and economic burden, necessitating innovative therapeutic approaches. Fibroblasts, characterized by their intrinsic cellular plasticity and multifunctional capabilities, play key roles in the pathophysiological processes underlying DFUs. Hyperglycemic conditions lead to a cascade of biochemical alterations that culminate in the dysregulation of fibroblast phenotype and function, which is the primary cause of impaired wound healing in DFUs. Biomaterials, particularly those engineered at the nanoscale, hold significant promise for enhancing DFU treatment outcomes. Electrospun nanofiber scaffolds, with their structural and compositional similarities to the natural extracellular matrix, serve as an effective substrate for fibroblast adhesion, proliferation, and migration. This review comprehensively summarizes the biological behavior of fibroblasts in DFUs and the mechanism mediating wound healing. At the same time, the mechanism of biological materials, especially electrospun nanofiber scaffolds, to improve the therapeutic effect by regulating the activity of fibroblasts was also discussed. By highlighting the latest advancements and clinical applications, we aim to provide a clear perspective on the future direction of DFU treatment strategies centered on fibroblast-targeted therapies.

Mechanism of Si Ni San Combined with Astragalus in Treating Hepatic Fibrosis: A Network Pharmacology and Molecular Docking Study

Si Ni San combined with Astragalus (SNSQ) has demonstrated significant efficacy in the treatment of hepatic fibrosis (HF), as confirmed by clinical practice. However, its pharmacological mechanism remains unclear. This study employs network pharmacology to identify key targets and proteins for molecular docking. Additionally, animal experiments were conducted to validate the network pharmacology results, providing further insights into the mechanism of SNSQ in treating HF. Effective compounds of SNSQ were screened from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) and Encyclopedia of Traditional Chinese Medicine (ETCM) databases. Molecular formula structures of these effective compounds were obtained from the PubChem database. Partial target proteins with a probability greater than 0.6 were sourced from the SWISS database. Uniprot IDs corresponding to these target proteins were retrieved from the SUPERPRED database. The remaining target proteins of the compounds were obtained from the Uniprot database based on the Uniprot IDs. The drug target proteins were then summarized. Target points related to HF were selected from the GeneCards and OMIM databases. Common target points were identified in the Venn diagram and imported into Cytoscape 3.9.1 software to construct the "SNSQ-effective compound-target pathway-HF" network. AutoDock software was used for molecular docking of compounds and target proteins with high-degree values. The common target points underwent GO function enrichment and KEGG pathway enrichment analysis using the DAVID database. An HF rat model was established, and serum AST and ALT activities were measured. The Hyp assay kit was utilized to detect the Hyp content in liver tissue. To the transcription levels of pro-inflammatory factors (IL-1β, TNF-α, IL-6) and anti-inflammatory factors (IL-10, TGF-β1, IL-4) in rat serum and liver.IL-1β, TNF-α, IL-10, and TGF-β1 were chosen for validation through ELISA. Western blotting and qRT-PCR were used to assess the expression of related proteins, namely NFKB1, NF-κBp65, NF-κBp50, α-SMA, and Col-1 in liver tissue. qRT-PCR was also employed to study the expression of ECM synthesis and proliferation-related genes, including Cyclin D1, TIMP1, COL1A1 in HSC-T6 cells and rat liver tissue, as well as the inhibition of the ECM-related gene MMP13 in HSC-T6 cells and rat liver tissue. A total of 16 valid compounds were predicted, with kaempferol, sitosterol, and isorhamnetin exhibiting high-degree values. KEGG enrichment analysis revealed that the target genes of SNSQ were enriched in multiple pathological pathways, with the NF-Kappa B signaling pathway being predominant. Molecular docking simulations indicated strong affinities between SNSQ's primary components-kaempferol, sitosterol, isorhamnetin-and NFKB1. Experimental results demonstrated significant reductions in AST, ALT, and Hyp levels in the SNSQ group. Pro-inflammatory factors (IL-1β, TNF-ɑ) were markedly reduced, while anti-inflammatory factors (IL-10, TGF-β1) were substantially increased. The protein expression and transcription levels of α-SMA and Col-1 were significantly decreased, whereas those of NFKB1, NF-κBp65, and NF-κBp50 were notably elevated. mRNA expression levels of Cyclin D1, TIMP1, COL1A1 in HSC-T6 cells and rat liver tissue were significantly decreased, whereas MMP13 mRNA expression level was significantly increased. Treatment of HF with SNSQ involves multiple targets and pathways, with a close association with the overexpression of NFKB1 and activation of the NF-Kappa B signaling pathway. Its mechanism is closely linked to the activation of inflammatory responses, HSC activation, and proliferation.

Oxygenous and biofilm-targeted nanosonosensitizer anchored with Pt nanozyme and antimicrobial peptide in the gelatin/sodium alginate hydrogel for infected diabetic wound healing

Sonodynamic therapy is an emerging therapeutic approach for combating bacterial infections. However, the characteristics of hypoxia, high H2O2 microenvironment, and the formation of persistent biofilms in diabetic wound sites limit its efficacy in this field. To address these issues, we developed a multifunctional antibacterial hydrogel dressing PPCN@Pt-AMPs/HGel with the cross-linked gelatin and sodium alginate as the matrix, where the nanosonosensitizer PCN-224 was decorated with the oxygen-generating Pt nanoenzyme and further coupled with a biofilm-targeting antimicrobial peptide via an interacting polydopamine layer. This nano-composite hydrogel displayed improved mechanical properties as well as good biocompatibility and biodegradability. The catalase-like activity of the nanoparticles facilitated the ultrasound-induced generation of the singlet oxygen due to the catalytic decomposition of the H2O2 into O2. In vitro results showed that the hydrogel dressing exhibited excellent antimicrobial ability under low-intensity ultrasound stimulation, which could effectively inhibit the newly formed biofilm and eliminate the full-grown biofilms. In the infected diabetic wound of rats, PPCN@Pt-AMPs/HGel significantly enhanced the wound healing rate under low-intensity ultrasound stimulation and improved the regeneration outcomes by promoting granulation tissue formation, angiogenesis, and type III collagen deposition. In conclusion, our study provides a novel and effective antibacterial hydrogel dressing for sonodynamic treatment of diabetic wounds.

3D bioprinting of engineered exosomes secreted from M2-polarized macrophages through immunomodulatory biomaterial promotes in vivo wound healing and angiogenesis

Biomaterial composition and surface charge play a critical role in macrophage polarization, providing a molecular cue for immunomodulation and tissue regeneration. In this study, we developed bifunctional hydrogel inks for accelerating M2 macrophage polarization and exosome (Exo) cultivation for wound healing applications. For this, we first fabricated polyamine-modified three-dimensional (3D) printable hydrogels consisting of alginate/gelatin/polydopamine nanospheres (AG/NSPs) to boost M2-exosome (M2-Exo) secretion. The cultivated M2-Exo were finally encapsulated into a biocompatible collagen/decellularized extracellular matrix (COL@d-ECM) bioink for studying angiogenesis and in vivo wound healing study. Our findings show that 3D-printed AGP hydrogel promoted M2 macrophage polarization by Janus kinase/signal transducer of activation (JAK/STAT), peroxisome proliferator-activated receptor (PPAR) signaling pathways and facilitated the M2-Exo secretion. Moreover, the COL@d-ECM/M2-Exo was found to be biocompatible with skin cells. Transcriptomic (RNA-Seq) and real-time PCR (qRT-PCR) study revealed that co-culture of fibroblast/keratinocyte/stem cells/endothelial cells in a 3D bioprinted COL@d-ECM/M2-Exo hydrogel upregulated the skin-associated signature biomarkers through various regulatory pathways during epidermis remodeling and downregulated the mitogen-activated protein kinase (MAPK) signaling pathway after 7 days. In a subcutaneous wound model, the 3D bioprinted COL@d-ECM/M2-Exo hydrogel displayed robust wound remodeling and hair follicle (HF) induction while reducing canonical pro-inflammatory activation after 14 days, presenting a viable therapeutic strategy for skin-related disorders.

Direct fibroblast reprogramming: an emerging strategy for treating organic fibrosis

Direct reprogramming has garnered considerable attention due to its capacity to directly convert differentiated cells into desired cells. Fibroblasts are frequently employed in reprogramming studies due to their abundance and accessibility. However, they are also the key drivers in the progression of fibrosis, a pathological condition characterized by excessive extracellular matrix deposition and tissue scarring. Furthermore, the initial stage of reprogramming typically involves deactivating fibrotic pathways. Hence, direct reprogramming offers a valuable method to regenerate target cells for tissue repair while simultaneously reducing fibrotic tendencies. Understanding the link between reprogramming and fibrosis could help develop effective strategies to treat damaged tissue with a potential risk of fibrosis. This review summarizes the advances in direct reprogramming and reveals their anti-fibrosis effects in various organs such as the heart, liver, and skin. Furthermore, we dissect the mechanisms of reprogramming influenced by fibrotic molecules including TGF-β signaling, mechanical signaling, inflammation signaling, epigenetic modifiers, and metabolic regulators. Innovative methods for fibroblast reprogramming like small molecules, CRISPRa, modified mRNA, and the challenges of cellular heterogeneity and senescence faced by in vivo direct reprogramming, are also discussed.

Progress of ADAM17 in Fibrosis-Related Diseases

Fibrosis leads to structural damage and functional decline and is characterized by an accumulation of fibrous connective tissue and a reduction in parenchymal cells. Because of its extremely poor prognosis, organ fibrosis poses a significant economic burden. In order to prevent and treat fibrosis more effectively, potential mechanisms need to be investigated. A disintegrin and metalloprotease 17 (ADAM17) is a membrane-bound protein. It regulates intracellular signaling and membrane protein degradation. Fibrosis mediated by ADAM17 has been identified as an important contributor, although the specific relationship between its multiple regulatory functions and the pathogenesis is unclear. This article describes ADAM17 activation, function, and regulation, as well as the role of ADAM17 mediated fibrosis injury in kidney, liver, heart, lung, skin, endometrium, and retina. To develop new therapeutic approaches based on ADAM17 related signal pathways.

CCN2 mediates fibroblast-macrophage interaction in knee arthrofibrosis based on single-cell RNA-seq analysis

Knee arthrofibrosis, characterized by excessive matrix protein production and deposition, substantially impairs basic daily functions, causing considerable distress and financial burden. However, the underlying pathomechanisms remain unclear. Here, we characterized the heterogeneous cell populations and cellular pathways by combination of flow cytometry and single-cell RNA-seq analysis of synovial tissues from six patients with or without knee arthrofibrosis. Increased macrophages and fibroblasts were observed with decreased numbers of fibroblast-like synoviocytes, endothelial cells, vascular smooth muscle cells, and T cells in the arthrofibrosis group compared with negative controls. Notably, fibroblasts were discovered to interact with macrophages, and lead to fibrosis through TGF-β pathway induced CCN2 expression in fibroblasts. CCN2 was demonstrated to be required for fibroblast pro-fibrotic functions (activation, proliferation, and migration) through TGFBR/SMAD pathway. The expression of CCN2 was positively correlated with the collagen volume and TGF-β expression and negatively associated with patient-reported outcome measures in another cohort of patients with knee arthrofibrosis. Our study reveals the role of CCN2 in the fibroblast-macrophage interaction through TGF-β pathway which might help to shed light on CCN2 as a potential biomarker.

Sustained release of migrasomes from a methacrylate-oxidized hyaluronic acid/methacrylated gelatin composite hydrogel accelerates skin wound healing

Migrasomes are newly discovered organelles with diverse physiological and pathological functions. Recent studies have shown that the local injection of fibroblast-derived migrasomes can accelerate skin wound healing; however, their effects are short-lived. To extend their therapeutic effects, we developed a skin-mimicking hydrogel (OHG) composed of methacrylate-oxidized hyaluronic acid (O-HA-MA) and methacrylated gelatin (GelMA). Migrasomes purified from human fibroblasts were uniformly distributed within the composite hydrogel, as confirmed by scanning electron cryomicroscopy. In a rat skin wound model, this novel hydrogel (OHG@Mig) significantly enhanced re-epithelialization, promoted angiogenesis, collagen deposition, and cell proliferation, ultimately accelerating wound healing more effectively than free migrasomes. To investigate the underlying mechanisms, we analyzed RNA-seq data from previous studies and performed immunohistochemistry. Our findings suggest that the sustained release of migrasomes modulates tissue levels of CXCL12 and IL-6, contributing to enhanced wound healing. In conclusion, our study demonstrates that the sustained release of fibroblast-derived migrasomes from a composite hydrogel enhances their therapeutic effects on skin wound healing, offering a promising regenerative strategy.

Hydrogen-Releasing Micromaterial Dressings: Promoting Wound Healing by Modulating Extracellular Matrix Accumulation Through Wnt/β-Catenin and TGF-β/Smad Pathways

Background: Wound healing is a complex and intricate biological process that involves multiple systems within the body and initiates a series of highly coordinated responses to repair damage and restore integrity and functionality. We previously identified that breathing hydrogen can significantly inhibit early inflammation, activate autologous stem cells, and promote the accumulation of extracellular matrix (ECM). However, the broader functions and downstream targets of hydrogen-induced ECM accumulation and tissue remodeling are unknown in the wound-healing process. Methods: Consequently, this thesis developed a hydrogen sustained-release dressing based on a micro storage material and reveals the mechanism of hydrogen in treating wound healing. Upon encapsulating the hydrogen storage materials, magnesium (Mg), and ammonia borane (AB), we found that SiO2@Mg exhibits superior sustained-release performance, while SiO2@AB demonstrates a higher hydrogen storage capacity. We used a C57/BL6 mouse full-thickness skin defect wound model to analyze and compare different hydrogen dressings. Results: It was identified that hydrogen dressings can significantly improve the healing rate of wounds by promoting epithelialization, angiogenesis, and collagen accumulation in wound tissue, and that the effect of slow-release dressings is better than of non-slow-release dressings. We also found that hydrogen dressing can promote transcriptome-level expression related to cell proliferation and differentiation and ECM accumulation, mainly through the Wnt1/β-catenin pathway and TGF-β1/Smad2 pathway. Conclusions: Overall, these results provide a novel insight into the field of hydrogen treatment and wound healing.

Inhibiting mechanotransduction prevents scarring and yields regeneration in a large animal model

Modulating mechanotransduction by inhibiting yes-associated protein (YAP) in mice yields wound regeneration without scarring. However, rodents are loose-skinned and fail to recapitulate key aspects of human wound repair. We sought to elucidate the effects of YAP inhibition in red Duroc pig wounds, the most human-like model of scarring. We show that one-time treatment with verteporfin, a YAP inhibitor, immediately after wounding is sufficient to prevent scarring and to drive wound regeneration in pigs. By performing single-cell RNA sequencing (scRNA-seq) on porcine wounds in conjunction with spatial proteomic analysis, we found perturbations in fibroblast dynamics with verteporfin treatment and the presence of putative pro-regenerative/profibrotic fibroblasts enriched in regenerating/scarring pig wounds, respectively. We also identified differences in enriched myeloid cell subpopulations after treatment and linked this observation to increased elaboration of interleukin-33 (IL-33) in regenerating wounds. Finally, we validated our findings in a xenograft wound model containing human neonatal foreskin engrafted onto nude mice and used scRNA-seq of human wound cells to draw parallels with fibroblast subpopulation dynamics in porcine wounds. Collectively, our findings provide support for the clinical translation of local mechanotransduction inhibitors to prevent human skin scarring, and they clarify a YAP/IL-33 signaling axis in large animal wound regeneration.

The efficacy of miR-141-3p to facilitate the healing of wounds and prevent scarring in mice by blocking the JNK/ERK pathway via HDAC6 silencing

PURPOSE

Adipose-derived mesenchymal stem cells (ADSCs) exosomes (AD-Exos) are a novel and promising therapeutic approach for skin damage repair. This investigation seeks to assess the potential clinical utility of miR-141-3p found in AD-exos for expediting wound healing.

METHODS

ADSCs were isolated from the wounded patients' tissue and validated via flow cytometry, and the mineralization and adipogenic capabilities of ADSCs were assessed respectively. Additionally, exosomes were isolated and identified. miR-141-3p and HDAC6.protein level were tested. Full-thickness wound models were created on the backs of mice, HE staining, ELISA, and immunohistochemistry were used to assess the influences of AD-exos on wound healing, inflammation, and new blood vessel formation Western blot was to assess the related-protein levels of JNK/ERK pathway. AQ1 Meanwhile, Dual-Luciferase assay confirmed the relationship between miR-141-3p and HDAC6.

RESULTS

The isolated cells highly express surface markers of mesenchymal stem cells and possess the potential for multidirectional differentiation, confirming them to be ADSCs. And miR-141-3p down-regulated but HDAC6 up-regulated in the serum and AD-exos of wounded patients. miR-141-3p could negatively modulate HDAC6. The miR-141-3p in AD-exos accelerated wound healing in mice, mitigated inflammatory responses and scarring in the injured skin tissue, and promoted angiogenesis, moreover, AD-exos could diminish the phosphorylation of JNK and ERK, while HDAC6 overexpressed could weaken these impacts.

CONCLUSION

miR-141-3p in AD-exos can target down regulate HDAC6 expression and inhibit JNK/ERK signaling pathway activation, thereby reducing wound inflammation and promoting angiogenesis and wound healing in mice.

Evaluation of Biological Properties and Beneficial Effects for a Sustainable and Conscious Exploitation of Achatina fulica Snails

In recent decades, there has been significant worldwide interest in the emergence of a new invasive species known as Achatina fulica. This is due to its dangerous habits for the environment, its biological characteristics and the fact that it is the intermediate host of several nematode parasites, such as Angiostrongylus cantonensis. This land snail species is native to tropical African countries, but has been introduced, accidentally or deliberately, to other parts of the world to be used for different purposes and is now established in a large part of the tropics. Since the 1980s, hundreds of researchers have been interested in the beneficial properties of its mucus, ranging from the antimicrobial and anticancer properties to the use of its powdered shell as a biocatalyst. This literature review aims to objectively describe the positive and negative aspects associated with the spread of A. fulica, highlighting in particular the opportunities for the local populations deriving from a conscious exploitation of this mollusc.