Basic fibroblast growth factor reduces scar by inhibiting the differentiation of epidermal stem cells to myofibroblasts via the Notch1/Jagged1 pathway

Proteins extracted from pearl oyster (Pinctada martensii) with efficient accelerated wound healing in vitro through promoting cell proliferation, migration, and collagen formation

Ethnopharmacological relevance

Pearl oyster (Pinctada martensii) is used in Chinese traditional medicine use in photoprotective, anti-inflammatory, and wound treatment.Aim of the study: This study explored whether the mucus protein of Pearl oyster (protein of Pinctada martensii, PMP) affects human skin fibroblast (HSF) proliferation, migration, collagen-related gene expression related to collagen formation, and in vivo healing effects.

Materials and methods

The PMP component was analyzed by LC-MS/MS. The cell viability was evaluated using a CCK-8 kit. The expression genes were measured by reverse transcription polymerase chain reaction. A full-thickness excisional wounding model in Sprague-Dawley (SD) rats was used to test the repairing effect of PMP in vivo, and Hematoxylin-Eosin (H&E) and Masson's Trichrome staining were applied to evaluate skin structure.

Results

The components of PMP were identified using LC-MS/MS proteomics, and a total of 3023 proteins were detected. The results of PMP-treated HSF showed that PMP effectively promoted cell proliferation by 1.6-fold and cell migration by 1.5-fold at a concentration of 1 mg/mL. Additionally, PMP treatment up-regulated the expression levels of collagen-related genes COL1A1, COL3A1, and MMP-1 in fibroblasts. Furthermore, PMP was applied in the therapy of full-thickness excisional wounds in rats. The results demonstrated that PMP significantly accelerated wound healing time, resulted in the recovery of dermal and epithelial thickness, and stimulated collagen regeneration. The regenerated skin closely resembled the structure of normal skin.

Conclusions

These findings provide solid evidence supporting the potential of PMP as a promising candidate for the treatment of skin wounds.

The efficacy of adipose-derived stem cells in burn injuries: a systematic review

BACKGROUND

Burn injuries can be associated with prolonged healing, infection, a substantial inflammatory response, extensive scarring, and eventually death. In recent decades, both the mortality rates and long-term survival of severe burn victims have improved significantly, and burn care research has increasingly focused on a better quality of life post-trauma. However, delayed healing, infection, pain and extensive scar formation remain a major challenge in the treatment of burns. ADSCs, a distinct type of mesenchymal stem cells, have been shown to improve the healing process. The aim of this review is to evaluate the efficacy of ADSCs in the treatment of burn injuries.

METHODS

A systematic review of the literature was conducted using the electronic databases PubMed, Web of Science and Embase. The basic research question was formulated with the PICO framework, whereby the usage of ADSCs in the treatment of burns in vivo was determined as the fundamental inclusion criterion. Additionally, pertinent journals focusing on burns and their treatment were screened manually for eligible studies. The review was registered in PROSPERO and reported according to the PRISMA statement.

RESULTS

Of the 599 publications screened, 21 were considered relevant to the key question and were included in the present review. The included studies were almost all conducted on rodents, with one exception, where pigs were investigated. 13 of the studies examined the treatment of full-thickness and eight of deep partial-thickness burn injuries. 57,1 percent of the relevant studies have demonstrated that ADSCs exhibit immunomodulatory effects during the inflammatory response. 16 studies have shown improved neovascularisation with the use of ADSCs. 14 studies report positive influences of ADSCs on granulation tissue formation, while 11 studies highlight their efficacy in promoting re-epithelialisation. 11 trials demonstrated an improvement in outcomes during the remodelling phase.

CONCLUSION

In conclusion, it appears that adipose-derived stem cells demonstrate remarkable efficacy in the field of regenerative medicine. However, the usage of ADSCs in the treatment of burns is still at an early experimental stage, and further investigations are required in order to examine the potential usage of ADSCs in future clinical burn care.

Targeting Signalling Pathways in Chronic Wound Healing

Chronic wounds fail to achieve complete closure and are an economic burden to healthcare systems due to the limited treatment options and constant medical attention. Chronic wounds are characterised by dysregulated signalling pathways. Research has focused on naturally derived compounds, stem-cell-based therapy, small molecule drugs, oligonucleotide delivery nanoparticles, exosomes and peptide-based platforms. The phosphoinositide-3-kinase (PI3K)/protein kinase B (AKT), Wingless-related integration (Wnt)/β-catenin, transforming growth factor-β (TGF-β), nuclear factor erythroid 2-related factor 2 (Nrf2), Notch and hypoxia-inducible factor 1 (HIF-1) signalling pathways have critical roles in wound healing by modulating the inflammatory, proliferative and remodelling phases. Moreover, several regulators of the signalling pathways were demonstrated to be potential treatment targets. In this review, the current research on targeting signalling pathways under chronic wound conditions will be discussed together with implications for future studies.

Constructing epidermal rete ridges using a composite hydrogel to enhance multiple signaling pathways for the maintenance of epidermal stem cell niche

The undulating microstructure rete ridge (RR) located at the junction between the dermis and epidermis plays a crucial role in improving skin mechanical properties and maintaining skin homeostasis. However, the investigation of RR microstructures is usually neglected in current tissue engineering for skin regeneration. Here, to create an epidermal model with RR microstructures, keratinocytes were cultured on a patterned GelMA-PEGDA hydrogel constructed using molding technology. Furthermore, grafting acryloylated Arg-Gly-Asp (RGD) peptides on the hydrogel surface significantly improved cell adhesion, fusion, and development. RT-PCR, Western blot, and immunofluorescence staining confirmed that cells on RR microstructures exhibited higher gene and protein expression associated with epidermal stem cells. RNA sequencing analysis of cells on RR microstructure showed higher gene expression profiles related to stem cell maintenance, basement membrane formation, and epidermal development. Furthermore, RT-PCR analysis of epidermal models of various dimensions demonstrated that smaller microstructures were more conducive to epidermal stem cell marker gene expression, which is analogous to human skin. Overall, we have successfully developed a method for integrating RR microstructures into an epidermal model that mimics natural skin to maintain epidermal stem cell niche, providing a valuable reference for researching skin regeneration within the fields of tissue engineering and regenerative medicine. STATEMENT OF SIGNIFICANCE: This study presents a method for precisely fabricating microstructures of skin rete ridges using composite hydrogels, thereby creating a skin model that mimics natural human skin. The findings reveal that this microstructure provides a stem cell niche that regulates the pathways and promotes the expression of proteins related to epidermal stem cells. This work advances the functional properties of tissue engineered skin and holds promise for improving the therapeutic efficacy of artificial skin grafts for the skin wounds.

Collagen synthesis in the skin: genetic and epigenetic aspects

One of the most important functions of the skin, mechanical, is provided by collagen fibers and their interaction with other elements of the extracellular matrix. Synthesis of collagen fibers is a complex multistep process. At each stage, disturbances may occur, leading, as a result, to a decrease in the mechanical properties of the connective tissue. In clinical practice, disorders of collagen synthesis are manifested through increased skin laxity and looseness and premature aging. In addition to the clinical presentation, it is important for the cosmetologist and dermatologist to understand the etiology and pathogenesis of collagenopathies. The present review summarizes and systematizes available information about the role of genetic and epigenetic factors in the synthesis of collagen fibers in the skin. Understanding the etiology of collagen synthesis disorders can allow doctors to prescribe pathogenetically grounded treatment with the most effective results and minimize adverse reactions.

Clinical Efficacy and Safety of Pulsed Dye Laser Combined with Pingyangmycin on Hyperplastic Scar after Acne

Background

Acne is the most common chronic inflammatory disease of hair follicles and sebaceous glands in dermatology. Hyperplastic scar (HS), a very common sequelae of acne, is also the most common scar type in clinical practice.

Objective

This research analyzed the clinical effectiveness and safety of pulsed dye laser (PDL) combined with pingyangmycin (PI) in the treatment of post-acne HS.

Methods

One hundred and nine patients with post-acne HS admitted in June 2020 were selected and divided into a research group (n = 52) and a control group (n = 57) according to the difference in treatment methods. The efficacy, incidence of adverse reactions, skin repair, treatment comfort, and satisfaction were compared between groups.

Results

The total effective rate was higher in the research group compared with the control group. No statistical difference was observed between groups in the incidence of adverse reactions. The research group showed better scar repair, skin improvement, and granulation tissue maturity than the control group. And compared with the control group, the growth factor of the research group was lower, while the treatment comfort and satisfaction, psychological state, and prognosis quality of life were higher. The two groups showed no notable difference in the recurrence rate.

Conclusions

PDL combined with PI can effectively improve the clinical efficacy, scar repair effect, overall skin status, and treatment experience of patients and boost the psychological state and prognostic quality of life of patients, which has great clinical application prospect for the treatment of HS.

A dopamine-methacrylated hyaluronic acid hydrogel as an effective carrier for stem cells in skin regeneration therapy

Adipose-derived stem cells (ADSCs) show potential in skin regeneration research. A previous study reported the failure of full-thickness skin self-repair in an injury area exceeding 4 cm in diameter. Stem cell therapies have shown promise in accelerating skin regeneration; however, the low survival rate of transplanted cells due to the lack of protection during and after transplantation leads to low efficacy. Hence, effective biomaterials for the delivery and retention of ADSCs are urgently needed for skin regeneration purposes. Here, we covalently crosslinked hyaluronic acid with methacrylic anhydride and then covalently crosslinked the product with dopamine to engineer dopamine-methacrylated hyaluronic acid (DA-MeHA). Our experiments suggested that the DA-MeHA hydrogel firmly adhered to the skin wound defect and promoted cell proliferation in vitro and skin defect regeneration in vivo. Mechanistic analyses revealed that the beneficial effect of the DA-MeHA hydrogel combined with ADSCs on skin defect repair may be closely related to the Notch signaling pathway. The ADSCs from the DA-MeHA hydrogel secrete high levels of growth factors and are thus highly efficacious for promoting skin wound healing. This DA-MeHA hydrogel may be used as an effective potential carrier for stem cells as it enhances the efficacy of ADSCs in skin regeneration.

Advances on the modification and biomedical applications of acellular dermal matrices

Acellular dermal matrix (ADM) is derived from natural skin by removing the entire epidermis and the cell components of dermis, but retaining the collagen components of dermis. It can be used as a therapeutic alternative to “gold standard” tissue grafts and has been widely used in many surgical fields, since it possesses affluent predominant physicochemical and biological characteristics that have attracted the attention of researchers. Herein, the basic science of biologics with a focus on ADMs is comprehensively described, the modification principles and technologies of ADM are discussed, and the characteristics of ADMs and the evidence behind their use for a variety of reconstructive and prosthetic purposes are reviewed. In addition, the advances in biomedical applications of ADMs and the common indications for use in reconstructing and repairing wounds, maintaining homeostasis in the filling of a tissue defect, guiding tissue regeneration, and delivering cells via grafts in surgical applications are thoroughly analyzed. This review expectedly promotes and inspires the emergence of natural raw collagen-based materials as an advanced substitute biomaterial to autologous tissue transplantation.

Graphical Abstract

Inhibition of Notch signaling pathway reduces angiogenesis in hypertrophic scar

OBJECTIVES

Hypertrophic scar (HS) is the most common pathological scar in clinical practice. During its formation, angiogenesis-related factors show dynamic expression. Modern studies have found that Notch signaling pathway has an extremely important role in maintaining the construction and remodeling of vascular endothelial cells and vascular network. The correlation between Notch signaling pathway and angiogenesis in hypertrophic scar has been rarely reported. This study aims to investigate correlation between Notch signaling pathway and the expression of angiogenic factors in a proliferative scar model.

METHODS

A total of 81 Sprague Dawley rats (SPF grade) were randomly assigned into a blank control group, a model group, and a blocker group. In the blocker group, a 2 cm diameter circular scald head was placed on the back of the rats for 10 s at 75 ℃ by using a constant temperature and pressure electrothermal scalding apparatus to form a rat deep II° burn model, and a hyperplastic scar model rat was obtained after natural healing of the wound skin (21 to 23 day epithelialization). A syringe was used to inject a needle from the normal skin around the scar at the 1st, 3rd, 5th, 7th, and 14th days after modeling. The γ-secretase inhibitor was injected locally at 2 mg/kg in a dilution of 0.1 mL at the base of the scar. The rats in the model group was injected with the same amount of saline after modeling; the rats in the blank control group was injected with the same amount of saline. Nine rats in each group was randomly killed by air embolization at the 21st, 28th, and 35th days, respectively. The protein expressions of collagen type I (COL-I) and collagen type III (COL-III) were detected by immunohistochemistry. The protein expressions of vascular endothelial growth factor (VEGF), angiopoietin 1 (Ang1), transforming growth factor-β1 (TGF-β1), and matrix metalloproteinase-2 (MMP-2) were detected by Western blotting.

RESULTS

Immunohistochemical results showed that, at the 21st,28th, and 35th days, the protein expressions of COL-I and COL-III in the model group were up-regulated compared with the blank control group (all P<0.05) and the protein expressions of COL-I and COL-III in the blocker group were decreased compared with the model group (all P<0.05). Western blotting showed that, at the 21st, 28th, and 35th days, the protein expressions of VEGF, Ang1, TGF-β1, and MMP-2 in the model group were significantly higher than those in the blank control group (all P<0.05). Except for the 21st day, the protein expressions of VEGF, Ang1, TGF-β1, and MMP-2 in the blocker group were lower than those in the model group at the 28th and 35th days (all P<0.05).

CONCLUSIONS

In the Sprague Dawley rat proliferative scar model, inhibition of Notch signaling pathway could attenuate the expressions of COL-I and COL-III, reduce traumatic scar proliferation, down-regulate the expressions of VEGF, Ang1, TGF-β1, and MMP-2, and inhibit angiogenesis. The expressions of angiogenesis-related factors appeare to be up-regulated during the formation of proliferative scar. When the Notch signaling pathway is inhibited, the up-regulated angiogenic factors show a decreasing trend and the proliferative scar is alleviated, which suggests that Notch signaling pathway may affect the formation of hyperplastic scar by regulating the expression of angiogenic factors.

Advances in Skin Wound and Scar Repair by Polymer Scaffolds

Scars, as the result of abnormal wound-healing response after skin injury, may lead to loss of aesthetics and physical dysfunction. Current clinical strategies, such as surgical excision, laser treatment, and drug application, provide late remedies for scarring, yet it is difficult to eliminate scars. In this review, the functions, roles of multiple polymer scaffolds in wound healing and scar inhibition are explored. Polysaccharide and protein scaffolds, an analog of extracellular matrix, act as templates for cell adhesion and migration, differentiation to facilitate wound reconstruction and limit scarring. Stem cell-seeded scaffolds and growth factors-loaded scaffolds offer significant bioactive substances to improve the wound healing process. Special emphasis is placed on scaffolds that continuously release oxygen, which greatly accelerates the vascularization process and ensures graft survival, providing convincing theoretical support and great promise for scarless healing.

Genetic and Epigenetic Aspects of Skin Collagen Fiber Turnover and Functioning

One of the most important functions of the skin, i.e., protection from mechanical damage, is ensured by collagen fibers and their interaction with other elements in the extracellular matrix. Collagen fiber turnover is a complex multi-stage process. At each stage, a disruption may occur, leading to a decrease in the mechanical properties of the connective tissue. Clinically, collagen formation disorders manifest themselves as increased flabbiness and looseness of the skin and as early signs of facial aging. In addition to the clinical picture, it is important for cosmetologists and dermatologists to understand the etiology and pathogenesis of collagenopathies. In our review, we summarized and systematized the available information concerning the role of genetic and epigenetic factors in skin collagen fiber turnover. Furthermore, we focused on the functions of different types of collagens present in the skin. Understanding the etiology of impaired collagen formation can allow doctors to prescribe pathogenetically based treatments, achieve the most effective results, and minimize adverse reactions.

Construction of tissue-engineered skin with rete ridges using co-network hydrogels of gelatin methacrylated and poly(ethylene glycol) diacrylate

Tissue-engineered skin, as a promising skin substitute, can be used for in vitro skin research and skin repair. However, most of research on tissue-engineered skin tend to ignore the rete ridges (RRs) microstructure, which enhances the adhesion between dermis and epidermis and provides a growth environment for epidermal stem cells. Here, we prepared and characterized photocurable gelatin methacrylated (GelMA) and poly(ethylene glycol) diacrylate (PEGDA) co-network hydrogels with different concentrations. Using a UV curing 3D printer, resin molds were designed and fabricated to create three-dimensional micropatterns and replicated onto GelMA-PEGDA scaffolds. Human keratinocytes (HaCaTs) and human skin fibroblasts (HSFs) were co-cultured on the hydrogel scaffold to prepare tissue-engineered skin. The results showed that 10%GelMA-2%PEGDA hydrogel provides the sufficient mechanical properties and biocompatibility to prepare a human skin model with RRs microstructure, that is, it presents excellent structural support, suitable degradation rate, good bioactivity and is suitable for long-term culturing. Digital microscope image analyses showed the micropattern was well-transferred onto the scaffold surface. Both in vitro and in vivo experiments confirmed the formation of the epidermal layer with undulating microstructure. In wound healing experiments, hydrogel can significantly accelerate wound healing. This study provides a simple and powerful way to mimic the structures of human skin and can make a contribution to skin tissue engineering and wound healing.

Role of fibroblast growth factor signalling in hepatic fibrosis

Fibrotic remodelling is a highly conserved protective response to tissue injury and it is essential for the maintenance of structural and functional tissue integrity. Also hepatic fibrosis can be considered as a wound-healing response to liver injury, reflecting a balance between liver repair and scar formation. In contrast, pathological fibrosis corresponds to impaired wound healing. Usually, the liver regenerates after acute injury. However, if the damaging mechanisms persist, the liver reacts with progressive and uncontrolled accumulation of extracellular matrix proteins. Eventually, excessive fibrosis can lead to cirrhosis and hepatic failure. Furthermore, cirrhosis is the major risk factor for the development of hepatocellular cancer (HCC). Therefore, hepatic fibrosis is the most critical pathological factor that determines the morbidity and mortality of patients with chronic liver disease. Still, no effective anti-fibrogenic therapies exist, despite the very high medical need. The regulation of fibroblast growth factor (FGF) signalling is a prerequisite for adequate wound healing, repair and homeostasis in various tissues and organs. The FGF family comprises 22 proteins that can be classified into paracrine, intracrine and endocrine factors. Most FGFs signal through transmembrane tyrosine kinase FGF receptors (FGFRs). Although FGFRs are promising targets for the treatment of HCC, the expression and function of FGFR-ligands in hepatic fibrosis is still poorly understood. This review summarizes the latest advances in our understanding of FGF signalling in hepatic fibrosis. Furthermore, the potential of FGFs as targets for the treatment of hepatic fibrosis and remaining challenges for the field are discussed.

Topical Application of Conditioned Medium from Hypoxically Cultured Amnion-Derived Mesenchymal Stem Cells Promotes Wound Healing in Diabetic Mice

BACKGROUND

Mesenchymal stem cells or their conditioned medium improve chronic wound healing, and their effect is enhanced by hypoxia. Diabetic foot ulcers are chronic wounds characterized by abnormal and delayed healing, which frequently require amputation. The authors evaluated the effect of topical application of conditioned medium from hypoxically cultured amnion-derived mesenchymal stem cells on wound healing in diabetic mice.

METHODS

Amnion-derived mesenchymal stem cells were cultured under 21% oxygen to prepare normoxic conditioned medium and under 1% oxygen to prepare hypoxic conditioned medium. Hydrogels containing standard medium, normoxic conditioned medium, or hypoxic conditioned medium were topically applied to excisional wounds of mice with streptozotocin-induced diabetes. Ulcer tissues were harvested on day 9; immunohistochemical and quantitative polymerase chain reaction analyses were performed to analyze angiogenesis, inflammatory cell infiltration, and expression levels of inflammation-related genes.

RESULTS

Hypoxic conditioned medium significantly enhanced wound closure, increased capillary density and epithelization, and reduced macrophage infiltration. It also tended to reduce the infiltration of neutrophils and enhance the infiltration of regulatory T cells; it showed a tendency to downregulate the expression of the inflammation-related genes interleukin-1β, interleukin-6, chemokine ligand 1, and chemokine ligand 2. Normoxic conditioned medium exhibited similar effects, although they were of lesser magnitude than those of hypoxic conditioned medium.

CONCLUSIONS

Hydrogels containing hypoxically cultured, amnion-derived mesenchymal stem cell conditioned medium accelerated wound healing in diabetic mice by enhancing angiogenesis, accelerating epithelization, and suppressing inflammation. Therefore, topical application of amnion mesenchymal stem cell-derived hypoxic conditioned medium could be a novel treatment for diabetic foot ulcers.

The Act of Controlling Adult Stem Cell Dynamics: Insights from Animal Models

Adult stem cells (ASCs) are the undifferentiated cells that possess self-renewal and differentiation abilities. They are present in all major organ systems of the body and are uniquely reserved there during development for tissue maintenance during homeostasis, injury, and infection. They do so by promptly modulating the dynamics of proliferation, differentiation, survival, and migration. Any imbalance in these processes may result in regeneration failure or developing cancer. Hence, the dynamics of these various behaviors of ASCs need to always be precisely controlled. Several genetic and epigenetic factors have been demonstrated to be involved in tightly regulating the proliferation, differentiation, and self-renewal of ASCs. Understanding these mechanisms is of great importance, given the role of stem cells in regenerative medicine. Investigations on various animal models have played a significant part in enriching our knowledge and giving In Vivo in-sight into such ASCs regulatory mechanisms. In this review, we have discussed the recent In Vivo studies demonstrating the role of various genetic factors in regulating dynamics of different ASCs viz. intestinal stem cells (ISCs), neural stem cells (NSCs), hematopoietic stem cells (HSCs), and epidermal stem cells (Ep-SCs).

Long non‑coding RNA HOTAIR promotes burn wound healing by regulating epidermal stem cells

Local transplantation of epidermal stem cells (ESCs) exerts a therapeutic effect on burn wounds. However, cell viability can impede their clinical application. HOX antisense intergenic RNA (HOTAIR) is involved in regulating adult tissue stem cells, as well as in developmental patterning and pluripotency. However, little is known about its role in regulating ESCs. The present study was performed to investigate the effects of HOTAIR in the modulation of ESCs and wound repair. Firstly, reverse transcription-quantitative PCR was used to detect the relative expression of HOTAIR during burn wound healing in mice to determine whether HOTAIR is associated with wound healing. Subsequently, ESCs derived from mouse skin were transfected with a lentiviral vector to overexpress or knockdown HOTAIR. The effects of HOTAIR on cell proliferation and differentiation were measured by 5-bromodeoxyuridine and MTT assays, and by assessing NANOG mRNA expression. Lastly, mice with burns were administered a subcutaneous injection of HOTAIR-overexpressing ESCs. Images were captured and histological analyses were performed to evaluate wound healing. The results revealed that the expression of HOTAIR gradually increased and peaked at day 7 post-burn and maintained at relatively high levels until day 14 post-burn during wound healing. Furthermore, overexpression of HOTAIR promoted ESC proliferation and maintained the stem cell state in vitro. By contrast, suppression of HOTAIR inhibited cell proliferation and cell stemness. It was also identified that HOTIR-overexpressing ESCs accelerated re-epithelialization and facilitated burn wound repair. In conclusion, the present findings confirmed an essential role of HOTAIR in the regulation of ESC proliferation and stemness. Therefore, targeting HOTAIR in ESCs may be a potentially promising therapy for burn wound healing.

Porcine acellular dermal matrix accelerates wound healing through miR-124-3p.1 and miR-139-5p

BACKGROUND AIMS

Cutaneous wound management is a major health problem and imposes a huge economic burden worldwide. Previous studies have demonstrated that wound healing is a highly coordinated process including epithelialization, angiogenesis, remodeling and scarring. This progression requires self-renewal, preservation and repair properties of stem cells. However, our understanding of the detailed internal regulatory mechanism following injury and the means to accelerate wound healing are limited.

METHODS

Our previous research revealed that porcine acellular dermal matrix (ADM) effectively promotes wound healing and scar formation through epidermal stem cells (ESCs), and this process is relevant to the alteration of internal miRNA levels. In this study, we investigated the regulatory function of porcine ADM treatment on miRNAs in ESCs.

RESULTS

We report that the treatment of porcine ADM reduced the levels of miR-124-3p.1 and miR-139-5p in wounds. MiR-124-3p.1 and miR-139-5p inhibited the expression of JAG1 and Notch1, respectively, by directly targeting miRNAs in ESCs.

CONCLUSIONS

This work demonstrates that porcine ADM induced down-regulation of miR-124-3p.1/139-5p in wounds and up-regulation of JAG1/Notch1 in ESCs, thus enhancing cutaneous wound healing.

Cell-Penetrating Peptides Enhance the Activity of Human Fibroblast Growth Factor 2 by Prolonging the Retention Time: A New Vision for Drug-Delivery Systems

Cell-penetrating peptides (CPPs) are defined by their ability to deliver cargo into cells and have been studied and developed as a promising drug-delivery system (DDS). However, the issue of whether the CPPs that have already entered the cells can be re-released or reused has not been studied. The purpose of this research was to construct CPP-conjugated human fibroblast growth factor 2 (hFGF2) and investigate whether they can be re-released from the cell membrane for reuse. This study combined hFGF2 with Tat or Ara27, a newly developed CPP derived from the zinc knuckle (CCHC-type) family protein of Arabidopsis. Human dermal fibroblast (HDF) was treated with Tat-conjugated hFGF2 (tFGF2) and Ara27-conjugated hFGF2 (NR-FGF2) for both long and short durations, and the effects on cell growth were compared. Furthermore, tFGF2 and NR-FGF2 re-released from the cells were quantified and the effects were evaluated by culturing HDF in a conditioned medium. Interestingly, the proliferation of HDF increased only when NR-FGF2 was treated for 1 h in endocytosis-independent manner. After 1 h, NR-FGF2 was significantly re-released, reaching a maximum concentration at 5 h. Furthermore, increased proliferation of HDF cultured in the conditioned medium containing re-released NR-FGF2 was discovered. While previous studies have focused on the delivery of cargo and its associated applications, this study has revealed that combinations of superior CPPs and therapeutics can be expected to prolong both the retention time and the cell-penetrating capacity, even in the presence of external factors. Therefore, CPPs can be applied in the context of topical drugs and cosmetics as a new DDS approach.

Fibronectin precoating wound bed enhances the therapeutic effects of autologous epidermal basal cell suspension for full-thickness wounds by improving epidermal stem cells' utilization

Background

Autologous epidermal basal cell suspension therapy has been proven to be one of the most effective treatments for full-thickness wounds. However, we found there remain obvious defects that significantly confined the utilization and function of the epidermal basal cells (EBCs), especially the epidermal stem cells (ESCs) in it. This study investigated whether precoating fibronectin (FN) on the wound bed before spraying EBCs could overcome these defects and further explored its possible mechanisms.

Methods

In the in vitro study, EBCs were isolated from the donor skin of patients who needed skin grafting. Different concentrations of FN were used to precoat culture dishes before cell culture; the adherent efficiency, proliferation and migration ability of ESCs were analyzed and compared with traditional collagen IV precoating.

In the in vivo study, Sprague–Dawley (SD) rats with full-thickness skin wounds were selected as full-thickness wounds’ model. For the experiment groups, 20 μg/ml FN was precoated on the wound bed 10 min before EBC spray. The quality of wound healing was estimated by the residual wound area rate, wound healing time, and hematoxylin and eosin (H&E) staining. Expression of ESC markers, neovascular markers, inflammation markers, and collagen formation and degradation markers was elucidated by immunohistochemistry (IHC), immunofluorescence (IF), western blot (WB), and RT-qPCR analysis.

Results

The in vitro study showed that the dishes precoated with 20 μg/ml FN had a similar adherent efficiency and colony formation rate with collagen IV, but it could improve the proliferation and migration of ESCs significantly. Similarly, in the in vivo study, precoating FN on wound bed before EBC spray also significantly promote wound healing by improving ESCs’ utilization efficiency, promoting angiogenesis, decreasing inflammations, and regulating collagen formation and degradation.

Conclusion

FN precoating wound bed before EBC spray could significantly promote full-thickness wound healing by improving the utilization and function of the ESCs and further by promoting angiogenesis, decreasing inflammations, and regulating collagen formation and degradation.

Graphical abstract

The Morphopathogenetic Aspects of Intraabdominal Adhesions in Children under One Year of Age

Background and Objectives: The morphopathogenesis of adhesions is a complex process, characterized by the accumulation of an extracellular matrix, inflammation and hypoxia. The regulatory role between morphopathogenic factors in adhesions has not yet been defined. The aim was to investigate the appearance of transforming growth factor beta (TGFβ), basic fibroblast growth factor (FGF-2), fibroblast growth factor receptor 1 (FGFR1), protein gene product 9.5 (PGP 9.5), chromogranin A (CgA), interleukin-1 alpha (IL-1α), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-7 (IL-7), interleukin-8 (IL-8), interleukin-10 (IL-10), tumor necrosis factor alpha (TNFα), matrix metaloproteinase-2 (MMP-2) and matrix metaloproteinase-2 tissue inhibitor (TIMP-2) in intraabdominal adhesions. Materials and Methods: The study material was obtained from 49 patients under one year of age with total or partial bowel obstruction. All factors were detected using immunohistochemistry methods and their relative distribution was evaluated by means of the semiquantitative counting method. Results: Intraabdominal adhesions are characterized by increased TGFβ, FGFR1 and decreased FGF-2, PGP 9.5, IL-1, IL-4, IL-8, TIMP-2 findings. The most significant changes observed were the remodulation of the extracellular matrix, promotion of neoangiogenesis and the maintenance of a prolonged inflammation. Conclusions: The increase in TGFβ, as well as the disbalance between MMP-2 and TIMP-2 proves an increased fibrosis in intraabdominal adhesions. Less detected FGF-2 and more prominent FGR1 findings points out a compensatory receptor stimulation in response to the lacking same factor. The decrease in PGP 9.5 indicate hypoxic injury and proves the stimulation of neoangiogenesis. An unpronounced IL-1 and marked IL-10 finding indicate the local tissue protection reaction, the decrease in IL-4 could be the direct cause of giant cells, but the decrease of IL-8 could confirm a delayed chemotaxis of inflammatory cells.

Inhibition of the Notch1 Pathway Promotes the Effects of Nucleus Pulposus Cell-Derived Exosomes on the Differentiation of Mesenchymal Stem Cells into Nucleus Pulposus-Like Cells in Rats

Stem cell therapies for intervertebral disc degeneration have been demonstrated as a promising strategy. Previous studies have shown that human nucleus pulposus cell- (NPC-) derived exosomes can induce the differentiation of mesenchymal stem cells (MSCs) into NP-like cells in vitro. However, the mechanism of MSC differentiation into NP-like cells with the induction of NPC exosomes is still unclear. Here, we verified the induction effects of NPC exosomes on the differentiation of MSCs into NP-like cells. In addition, the Notch1 pathway was downregulated in this process. Then, DAPT and soluble Jagged1 (SJAG) were applied to inhibit or enhance the expression of the Notch1 pathway, respectively, resulting in the upregulation or downregulation of collagen II, aggrecan, and Sox9 in MSCs. Knocking down of Notch1 protein facilitated the effects of NPC exosomes on the differentiation of MSCs into NP-like cells. NPC exosomes were more effective than an indirect coculture system in terms of the differentiation of MSCs into NP-like cells. Inhibition of NPC exosome secretion with Rab27a siRNA prevented the induction effects of an indirect coculture system on the differentiation of MSCs into NP-like cells. Transwell migration assays revealed that NPC exosomes could promote the migration of MSCs. Taken together, the Notch1 pathway was negatively associated with the differentiation of MSCs into NP-like cells with the treatments of NPC exosomes. Inhibition of the Notch1 pathway facilitates NPC exosome-induced differentiation of MSCs into NP-like cells in vitro. NPC exosomes play a key role in the differentiation of MSCs into NP-like cells in an indirect coculture system of NPCs and MSCs.

Evaluation of fibroblast growth factor-2 on the proliferation of osteogenic potential and protein expression of stem cell spheroids composed of stem cells derived from bone marrow

Fibroblast growth factor-2 (FGF-2) is reported to have various functions and is considered a key human mesenchymal stem cell mitogen, often supplemented to increase human mesenchymal stem cell growth rates. The purpose of this study was to evaluate the effects of FGF-2 on cellular viability and osteogenic differentiation using three-dimensional cell spheroids of stem cells. Three-dimensional cell spheroids were fabricated using concave silicon elastomer-based microwells in the presence of FGF-2 at concentrations of 0, 30, 60 and 90 ng/ml. Qualitative cellular viability was determined with a confocal microscope, and quantitative cellular viability was evaluated using a Cell Counting Kit-8 assay. Alkaline phosphatase activity and Alizarin Red S staining were used to assess osteogenic differentiation. Spheroids were well formed in silicon elastomer-based concave microwells on Day 1. The average spheroid diameters at Day 1 for FGF-2 at 0, 30, 60 and 90 ng/ml were 202.2±3.0, 206.6±22.6, 208.8±6.8 and 196.6±26.7 µm, respectively (P>0.05). The majority of the cells in the cell spheroids emitted green fluorescence. The relative Cell Counting Kit-8 assay values for FGF-2 at 0, 30, 60 and 90 ng/ml at Day 1 were 100.0±5.5, 101.8±8.8, 99.2±4.8 and 103.4±9.6% (P>0.05). The addition of FGF-2 at 60 ng/ml concentration produced the highest value for alkaline phosphatase activity. Mineralized extracellular deposits were evenly observed in each group, and the highest value was identified for FGF-2 groups at 60 ng/ml concentration for Alizarin Red S staining. Based on these findings, it was concluded that FGF-2 may increase alkaline phosphatase activity or Alizarin Red S staining, and further studies are needed to fully elucidate the mechanisms of FGF-2.

Achillea biebersteinni Afan may inhibit scar formation: In vitro study

Background

One of the major problems in wound healing is scar formation; however, there are few ways to prevent or treat it. Different species of Achillea are used to treat wounds in folk medicine from the past but there are few studies on the effect of it on wound healing and inhibition of scar formation. The aim of this study was to investigate the effect of Achillea biebersteinii Afan hydroethanolic extract on the expression of TGFβ1 and bFGF as effective growth factors of wound healing in mouse embryonic fibroblast cells.

Methods

Mouse embryonic fibroblast cells were exposed to different concentrations of Achillea extract at two different time (12 and 24 hr); the expression of TGFβ1 and bFGF was performed by real‐time‐PCR and ELISA at the level of gene and protein.

Results

It was observed that the plant extract at 5 and 10 µg/ml downregulated the expression of TGFβ1 and upregulated the expression of bFGF at the level of gene and protein.

Conclusion

The results showed that the pattern of changes in the expression of TGFβ1 and bFGF by Achillea biebersteinni Afan extract may inhibit scar formation.

The 1470 nm diode laser with an intralesional fiber device: a proposed solution for the treatment of inflamed and infected keloids

Background

Keloids are the result of abnormal wound healing and often are subject to infections and recurrent inflammation. We present a study conducted with a 1470 nm diode laser using an intralesional optical fiber device for the treatment of inflamed keloid scars. We evaluate its efficacy as a novel alternative method to decrease keloid infection and inflammation.

Methods

The patients who underwent 1470 nm laser treatment from February 2016 to February 2018 at the plastic and reconstructive surgery department of the Shanghai Ninth People’s Hospital Affiliated to Shanghai Jiao Tong University with keloid accompanying serious local infection and fester were included. Patients took curative effect evaluation before and 1 year after the treatment. The test items included infection frequency in each year; pain, by visual analogue scale (VAS); itch, using VAS; quality of life (QOL), using QOL scale; and blood supply, using PeriCam PSI.

Results

A total of 19 patients (mean age 35.21 years, range 11–66) with history of inflamed keloids with episodes of infection or abscess were enrolled. Patients underwent to a 1470 nm laser therapy for average of 1.16 times. After treatment, infection frequency and blood supply in keloids were reduced (p < 0.001). Pain, itching, and QOL were improved (p < 0.001).

Conclusion

The present study shows that 1470 nm fiber laser treatment could improve inflamed keloids fairly well by decreasing inflammation, and a relative stabilization of collagen composition. Therefore, it is an effective minimally invasive scar therapy, but further studies are essential to confirm the present results.

The monoclonal antibody EPR1614Y against the stem cell biomarker keratin K15 lacks specificity and reacts with other keratins

Keratin 15 (K15), a type I keratin, which pairs with K5 in epidermis, has been used extensively as a biomarker for stem cells. Two commercial antibodies, LHK15, a mouse monoclonal and EPR1614Y, a rabbit monoclonal, have been widely employed to study K15 expression. Here we report differential reactivity of these antibodies on epithelial cells and tissue sections. Although the two antibodies specifically recognised K15 on western blot, they reacted differently on skin sections and cell lines. LHK15 reacted in patches, whereas EPR1614Y reacted homogenously with the basal keratinocytes in skin sections. In cultured cells, LHK15 did not react with K15 deficient NEB-1, KEB-11, MCF-7 and SW13 cells expressing only exogenous K8 and K18 but reacted when these cells were transduced with K15. On the other hand, EPR1614Y reacted with these cells even though they were devoid of K15. Taken together these results suggest that EPR1614Y recognises a conformational epitope on keratin filaments which can be reconstituted by other keratins as well as by K15. In conclusion, this report highlights that all commercially available antibodies may not be equally specific in identifying the K15 positive stem cell.

Role of caveolin-1 in epidermal stem cells during burn wound healing in rats

Local transplantation of stem cells has therapeutic effects on skin damage but cannot provide satisfactory wound healing. Studies on the mechanisms underlying the therapeutic effects of stem cells on skin wound healing will be needed. Hence, in the present study, we explored the role of Caveolin-1 in epidermal stem cells (EpiSCs) in the modulation of wound healing. We first isolated EpiSCs from mouse skin tissues and established stable EpiSCs with overexpression of Caveolin-1 using a lentiviral construct. We then evaluated the epidermal growth factor (EGF)-induced cell proliferation ability using cell counting Kit-8 (CCK-8) assay and assessed EpiSC pluripotency by examining Nanog mRNA levels in EpiSCs. Furthermore, we treated mice with skin burn injury using EpiSCs with overexpression of Caveolin-1. Histological examinations were conducted to evaluate re-epithelialization, wound scores, cell proliferation and capillary density in wounds. We found that overexpression of Caveolin-1 in EpiSCs promoted EGF-induced cell proliferation ability and increased wound closure in a mouse model of skin burn injury. Histological evaluation demonstrated that overexpression of Caveolin-1 in EpiSCs promoted re-epithelialization in wounds, enhanced cellularity, and increased vasculature, as well as increased wound scores. Taken together, our results suggested that Caveolin-1 expression in the EpiSCs play a critical role in the regulation of EpiSC proliferation ability and alteration of EpiSC proliferation ability may be an effective approach in promoting EpiSC-based therapy in skin wound healing.

Curcumin promotes burn wound healing in mice by upregulating caveolin-1 in epidermal stem cells

We aimed to explore the effect of curcumin on epidermal stem cells (ESCs) in regulating wound healing and the underlying molecular mechanism. We treated mouse ESCs isolated from skin tissues with curcumin, and then assessed the proliferation ability of cells induced by epidermal growth factor using cell counting kit-8 assay. The pluripotency of ESCs was evaluated as well through examination of Nanog expression in ESCs. Further, mice with skin burns were treated with ESCs with or without curcumin pretreatments. Histological evaluations were then preformed to determine wound scores, cell proliferation, reepithelialization, and capillary density in wounds. Curcumin treatment promoted the proliferative ability of ESCs and conditioned medium from curcumin-treated ESCs enhanced human umbilical vein endothelial cell (HUVEC) tube formation. We also found curcumin treatment elevated caveolin-1 expression in ESCs, which was required for the beneficial effect of curcumin on ESC proliferation and HUVEC tube formation. Next, using a mouse model of burn wound healing, curcumin-treated ESCs exhibited enhanced wound closure, which also required caveolin-1 expression. Our current study demonstrates the beneficial effect of curcumin on burn wound healing in mice, which is mediated by upregulating caveolin-1 in ESCs, and supports the potential therapeutic role of curcumin in ESC-based treatment against skin wound healing.

Effects of porcine acellular dermal matrix treatment on wound healing and scar formation: Role of Jag1 expression in epidermal stem cells

Skin wound healing involves Notch/Jagged1 signaling. However, little is known how Jag1 expression level in epidermal stem cells (ESCs) contributes to wound healing and scar formation. We applied multiple cellular and molecular techniques to examine how Jag1 expression in ESCs modulates ESCs differentiation to myofibroblasts (MFB) in vitro, interpret how Jag1 expression in ESCs is involved in wound healing and scar formation in mice, and evaluate the effects of porcine acellular dermal matrix (ADM) treatment on wound healing and scar formation. We found that Jag1, Notch1 and Hes1 expression was up-regulated in the wound tissue during the period of wound healing. Furthermore, Jag1 expression level in the ESCs was positively associated with the level of differentiation to MFB. ESC-specific knockout of Jag1 delayed wound healing and promoted scar formation in vivo. In addition, we reported that porcine ADM treatment after skin incision could accelerate wound closure and reduce scar formation in vivo. This effect was associated with decreased expression of MFB markers, including α-SMA Col-1 and Col-III in wound tissues. Finally, we confirmed that porcine ADM treatment could increase Jag1, Notch1 and Hesl expression in wound tissues. Taken together, our results suggested that ESC-specific Jag1 expression levels are critical for wound healing and scar formation, and porcine ADM treatment would be beneficial in promoting wound healing and preventing scar formation by enhancing Notch/Jagged1 signaling pathway in ESCs.

Fibroblast Growth Factor 2 as an Antifibrotic: Antagonism of Myofibroblast Differentiation and Suppression of Pro-Fibrotic Gene Expression

Fibrosis is a pathological condition that is characterized by the replacement of dead or damaged tissue with a nonfunctional, mechanically aberrant scar, and fibrotic pathologies account for nearly half of all deaths worldwide. The causes of fibrosis differ somewhat from tissue to tissue and pathology to pathology, but in general some of the cellular and molecular mechanisms remain constant regardless of the specific pathology in question. One of the common mechanisms underlying fibroses is the paradigm of the activated fibroblast, termed the "myofibroblast," a differentiated mesenchymal cell with demonstrated contractile activity and a high rate of collagen deposition. Fibroblast growth factor 2 (FGF2), one of the members of the mammalian fibroblast growth factor family, is a cytokine with demonstrated antifibrotic activity in non-human animal, human, and in vitro models. FGF2 is highly pleiotropic and its receptors are present on many different cell types throughout the body, lending a great deal of variety to the potential mechanisms of FGF2 effects on fibrosis. However, recent reports demonstrate that a substantial contribution to the antifibrotic effects of FGF2 comes from the inhibitory effects of FGF2 on connective tissue fibroblasts, activated myofibroblasts, and myofibroblast progenitors. FGF2 demonstrates effects antagonistic towards fibroblast activation and towards mesenchymal transition of potential myofibroblast-forming cells, as well as promotes a gene expression paradigm more reminiscent of regenerative healing, such as that which occurs in the fetal wound healing response, than fibrotic resolution. With a better understanding of the mechanisms by which FGF2 alters the wound healing cascade and results in a shift away from scar formation and towards functional tissue regeneration, we may be able to further address the critical need of therapy for varied fibrotic pathologies across myriad tissue types.

Inhibition of Hes1 enhances lapatinib sensitivity in gastric cancer sphere-forming cells

It has been considered that the neurogenic locus notch homolog protein (Notch) signaling pathway serves an essential role in cellular differentiation, proliferation and apoptosis. However, the function of the Notch signaling pathway in gastric cancer stem cells (GCSCs) and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) sensitivity remains unclear. The present study aimed to delineate the role of the Notch1 signaling pathway in GCSCs and lapatinib sensitivity. Sphere-forming cells were separated from human gastric cancer MKN45 parental cells. The sphere-forming cells exhibited characteristics of CSCs and higher Notch1 expression compared with that of parental cells. To investigate the role of the Notch1 signaling pathway in GCSCs, the expression of transcription factor Hes1 (Hes1) was knocked down using small interfering RNA against Hes1. It was observed that Hes1 expression was significantly downregulated in knocked down cells. The inhibition of Hes1 suppressed the properties of CSCs, as indicated by significant decreases in the expression of the transcription factor sex determining region Y-box 2, epithelial cell adhesion molecule and the homeobox protein Nanog and reduced spheroid colony formation. In addition, epithelial-mesenchymal transition was significantly impaired in sphere-forming cells following Hes1 knockdown. Furthermore, the inhibition of Hes1 effectively enhanced lapatinib sensitivity in sphere-forming cells. These results suggest that sphere-forming gastric cancer cells possess the characteristics of CSCs, and that the Notch1 signaling pathway serves an essential role in the maintenance of CSCs and lapatinib sensitivity.