Enhanced Keratinocyte Proliferation Research Articles

Biomedical Application Prospects of Gadolinium Oxide Nanoparticles for Regenerative Medicine.

The aim was to study the possibilities of biomedical application of gadolinium oxide nanoparticles (Gd2O3 NPs) synthesized under industrial conditions, and evaluate their physicochemical properties, redox activity, biological activity, and safety using different human cell lines. The powder of Gd2O3 NPs was obtained by a process of thermal decomposition of gadolinium carbonate precipitated from nitrate solution, and was studied using transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, mass spectrometry, and scanning electron microscopy (SEM) with energy dispersive X-ray analyzer (EDX). The redox activity of different concentrations of Gd2O3 NPs was studied by the optical spectroscopy (OS) method in the photochemical degradation process of methylene blue dye upon irradiation with an optical source. Biological activity was studied on different human cell lines (keratinocytes, fibroblasts, mesenchymal stem cells (MSCs)) with evaluation of the effect of a wide range of Gd2O3 NP concentrations on metabolic and proliferative cellular activity (MTT test, direct cell counting, dead cell assessment, and visual assessment of cytoarchitectonics). The test of migration activity assessment on a model wound was performed on MSC culture. According to TEM data, the size of the NPs was in the range of 2-43 nm, with an average of 20 nm. XRD analysis revealed that the f Gd2O3 nanoparticles had a cubic structure (C-form) of Gd2O3 (Ia3)¯ with lattice parameter a = 10.79(9) Å. Raman spectroscopy showed that the f Gd2O3 nanoparticles had a high degree of crystallinity. By investigating the photooxidative degradation of methylene blue dye in the presence of f Gd2O3 NPs under red light irradiation, it was found that f Gd2O3 nanoparticles showed weak antioxidant activity, which depended on the particle content in the solution. At a concentration of 10-3 M, the highest antioxidant activity of f Gd2O3 nanoparticles was observed when the reaction rate constant of dye photodegradation decreased by 5.5% to 9.4 × 10-3 min-1. When the concentration of f Gd2O3 NPs in solution was increased to 10-2 M upon irradiation with a red light source, their antioxidant activity changed to pro-oxidant activity, accompanied by a 15% increase in the reaction rate of methylene blue degradation. Studies on cell lines showed a high level of safety and regenerative potential of Gd2O3 NPs, which stimulated fibroblast metabolism at a concentration of 10-3 M (27% enhancement), stimulated keratinocyte metabolism at concentrations of 10-3 M-10-5 M, and enhanced keratinocyte proliferation by an average of 35% at concentrations of 10-4 M. Furthermore, it accelerated the migration of MSCs, enhancing their proliferation, and promoting the healing of the model wound. The results of the study demonstrated the safety and regenerative potential of redox-active Gd2O3 NPs towards different cell lines. This may be the basis for further research to develop nanomaterials based on Gd2O3 NPs for skin wound healing and in regenerative medicine generally.

Keratinocyte Integrin α3β1 Promotes Efficient Healing of Wound Epidermis

To date, studies of the role for epidermal integrin α3β1 in cutaneous wound re-epithelialization have produced conflicting results: wound studies in skin from global α3-null neonatal mice have implicated the integrin in promoting timely wound re-epithelialization, whereas studies in adult mice with constitutive, epidermal-specific α3β1 deletion have not. The objective of this study was to utilize a model of inducible α3β1 deletion in the epidermis to clarify the role of α3β1 in the healing of adult wounds. We utilized the recently developed transgenic K14Cre-ERT::α3flx/flx mice (ie, inducible α3 epidermal knockout), permitting us to delete floxed Itga3 alleles (α3flx/flx) from epidermis just prior to wounding with topical treatment of 4-hydroxytamoxifen. This allows for the elucidation of α3β1-dependent wound healing in adult skin, free from compensatory mechanisms that may occur after embryonic deletion of epidermal α3β1 in the widely used constitutive α3β1-knockout mouse. We found that re-epithelializing wound gaps are larger in inducible α3 epidermal knockout mice than in control mice, indicating delayed healing, and that epidermal integrin α3β1 promotes healing of wounds, at least in part by enhancing keratinocyte proliferation. This work provides essential rationale for future studies to investigate integrin α3β1 as a therapeutic target to facilitate wound healing.

Dihydroavenanthramide D Enhances Skin Barrier Function through Upregulation of Epidermal Tight Junction Expression.

Skin barrier dysfunction and thin epidermis are hallmarks of sensitive skin and contribute to premature aging. Avenanthramides are the primary bioactive components of colloidal oatmeal, a commonly used treatment to enhance skin barrier function. This study investigated the relationship between skin barrier function and epidermal characteristics and explored the potential of dihydroavenanthramide D (dhAvD), a synthetic avenanthramide, to improve the skin barrier. We observed a significant correlation between impaired skin barrier function and decreased epidermal thickness, suggesting that a weakened barrier contributes to increased sensitivity. Our in vitro results in HaCaT cells demonstrated that dhAvD enhances keratinocyte proliferation, migration, and tight junction protein expression, thereby strengthening the skin barrier. To mimic skin barrier dysfunction, we treated keratinocytes and full-thickness skin equivalents with IL-4 and IL-13, cytokines that are implicated in atopic dermatitis, and confirmed the downregulation of tight junction and differentiation markers. Furthermore, dhAvD treatment restored the barrier function and normalized the expression of key epidermal components, such as tight junction proteins and natural moisturizing factors, in keratinocytes treated with inflammatory cytokines. In the reconstructed human skin model, dhAvD promoted both epidermal and dermal restoration. These findings suggest that dhAvD has the potential to alleviate skin sensitivity and improve skin barrier function.

Pyroxylin-based liquid bandage forms a mechanically active protective film to facilitate skin wound healing in mice

Wound healing requires interplay between cells and molecules. Recent evidence has demonstrated that liquid bandages promote wound healing by forming a protective barrier against contamination, attenuating inflammation, and enhancing re-epithelialization and angiogenesis. In this study, we evaluated the wound healing activity of pyroxylin-based liquid bandage (LiQuiPlast®) in eight-week-old C57BL/6 male mice by generating a single 4 mm diameter full-thickness excisional skin wound on the dorsum. In the LiQuiPlast® group, the liquid bandage was applied on day 0 and was replaced every four days. Wound size was monitored every day for two weeks. The results showed that LiQuiPlast® was mechanically active (induced wound contraction), which promoted a significant wound size reduction (27 %−39 %, compared to the control group) on days 1–4 postinjury. In addition, a significant reduction in wound size was observed again in the LiQuiPlast® group (25 %−29 %, compared to the controls) on days 8−9 postinjury. LiQuiPlast®-treated wounds showed no scab. Immunohistochemistry analyses displayed a reduction in neutrophils and tumor necrosis factor-α levels in LiQuiPlast®-treated wounds, compared to the control group on day 4 postinjury (the inflammatory phase). In addition, LiQuiPlast®-treated mice had enhanced keratinocyte proliferation than control mice during this time. On day 13 postinjury, LiQuiPlast® significantly reduced hypertrophic scarring and enhanced expression and reorganization of collagen fiber compared to control mice. In conclusion, we show that LiQuiPlast® acts as a mechanically active protective film, which promotes moist wound healing by promoting wound contraction, no scab formation, attenuated inflammation, enhanced keratinocyte proliferation, and decreased scarring.

Rhein-chitosan in situ hydrogel promotes wound healing in diabetic mice

Chronic inflammation and infection often lead to delayed healing in skin wounds of patients with diabetes, presenting a significant challenge in clinical wound repair. In an effort to tackle this issue, we explored the utilization of the natural compounds Rhein and chitosan in the creation of a crosslinked in situ gel. Developed as Rhein-chitosan in situ hydrogel (CS-Rh gel), this formulation has the ability to gel at body temperature, making it suitable for irregular wounds of varying shapes. Our experimental investigations have demonstrated its excellent biocompatibility, controlled release of Rhein, biodegradability, anti-inflammatory properties, antibacterial effect, as well as its ability to enhance keratinocyte proliferation and migration. Furthermore, in vivo studies have confirmed that CS-Rh gel can effectively mitigate tissue inflammation, promote collagen deposition, and significantly accelerate wound healing in diabetic mice within a short timeframe of two weeks. Consequently, this innovative approach holds promise as a viable therapeutic strategy for supporting the healing of diabetic wounds in a clinical setting.

Interleukin-17 Regulates Keratinocyte Proliferation in Psoriasis Through the MALAT1/miR-125b/BRD4 Axis

This study investigated the role of LncRNA MALAT1 in psoriasis development. Serum from psoriasis patients and healthy subjects was collected, and IL-17 levels were measured. HaCaT cells were exposed to IL-17 and transfected with shMALAT1 or treated with Secukinumab. Cell viability, proliferation, and cell cycle were assessed, along with the expression of key cell cycle regulators. Various LncRNAs were analyzed, and the interaction between MALAT1 and p65 was confirmed through luciferase assays and ChIP assays. Results showed that IL-17 treatment increased cell proliferation and MALAT1 expression. p65 binding to the MALAT1 promoter enhanced keratinocyte proliferation. Secukinumab mitigated IL-17-induced cell proliferation and rescued miR-125b expression, which was reduced by IL-17. IL-17 also elevated BRD4 expression, which Secukinumab attenuated. In summary, IL-17 promotes HaCaT cell proliferation by upregulating MALAT1, with p65 facilitating this process. Secukinumab effectively counteracts these effects, restoring miR-125b levels and reducing BRD4 expression. These findings provide new insights into potential treatments for psoriasis.

HMGB1 Carried by Small Extracellular Vesicles Potentially Plays a Role in Promoting Acquired Middle Ear Cholesteatoma.

Cholesteatoma is a specific medical condition involving the abnormal, non-cancerous growth of skin-like tissue in the middle ear, potentially leading to a collection of debris and even infections. The receptor for advanced glycation (RAGE) and its ligand, high-mobility box 1 (HMGB1), are both known to be overexpressed in cholesteatoma and play a potential role in the pathogenesis of the disease. In this study, we investigated the role of small extracellular vesicles (sEVs) in carrying HMGB1 and inducing disease-promoting effects in cholesteatoma. No significant differences in the concentration of isolated sEVs in the plasma of cholesteatoma patients (n = 17) and controls (n = 22) were found (p > 0.05); however, cholesteatoma-derived sEVs carried significantly higher levels of HMGB1 (p < 0.05). In comparison to sEVs isolated from the plasma of controls, cholesteatoma-derived sEVs significantly enhanced keratinocyte proliferation and IL-6 production (p < 0.05), potentially by engaging multiple activation pathways including MAPKp44/p42, STAT3, and the NF-κB pathway. Thus, HMGB1(+) sEVs emerge as a novel factor potentially promoting cholesteatoma progression.

Dried human-cultured epidermis accelerates wound healing in a porcine partial-thickness skin defect model.

Autologous cultured epidermis (CE) is an effective approach for overcoming the deficiency of donor sites to treat extensive burns. However, the production of autologous CE takes 3-4 weeks, which prevents its use during the life-threatening period of severe burns. In contrast, allogeneic CE can be prepared in advance and used as a wound dressing, releasing several growth factors stimulating the activity of recipient cells at the application site. Dried CE is prepared by drying CEs under controlled temperature and humidity conditions until all the water is completely removed and no viable cells are present. Dried CE accelerates wound healing in a murine skin defect model and is potentially a new therapeutic strategy. However, the dried CE safety and efficacy have not yet been studied in large animal models. Therefore, we studied the safety and efficacy of human-dried CE in wound healing using a miniature swine model. Human CE was manufactured using Green's method from donor keratinocytes. Three types of CEs (Fresh, Cryopreserved, and Dried) were prepared, and the ability of each CE to promote keratinocyte proliferation was confirmed invitro. Extracts of the three CEs were added to keratinocytes seeded in 12-well plates, and cell proliferation was evaluated using the WST-8 assay for 7 days. Next, we prepared a partial-thickness skin defect on the back of a miniature swine and applied three types of human CE to evaluate wound healing promotion. On days 4 and 7, the specimens were harvested for hematoxylin-eosin, AZAN, and anti-CD31 staining to assess epithelialization, granulation tissue, and capillary formation. The conditioned medium containing dried CE extract significantly enhanced keratinocyte proliferation compared to the control group (P<0.05). Invivo experiments revealed that human-dried CE significantly accelerated epithelialization at day 7 to the same extent as fresh CE, compared to the control group (P<0.05). The three CE groups similarly affected granulation formation and neovascularization. Dried CE accelerated epithelialization in a porcine partial-thickness skin defect model, suggesting that it may be an effective burn treatment alternative. A clinical study with a long-term follow-up is needed to assess the applicability of CEs in clinics.

Puerarin Improves Dexamethasone-Impaired Wound Healing In Vitro and In Vivo by Enhancing Keratinocyte Proliferation and Migration

The delayed and impaired wound healing caused by dexamethasone (DEX) is commonly reported. Puerarin, the major isoflavone found in Pueraria montana var. lobata (Willd.) Sanjappa &amp; Pradeep promoted the wound healing process in diabetic rats. However, the effects and underlying mechanisms of puerarin on DEX-impaired wound healing have not been investigated. This study examined the potential uses of puerarin in upregulating keratinocyte proliferation and migration in dexamethasone (DEX)-suppressed wound healing model. The effects of puerarin on wound healing in vivo were investigated by taking full-thickness 5 mm punch biopsies from the dorsal skin of BALB/c mice and then treating them topically with 0.1% DEX. For the in vitro study, DEX-treated HaCaT cells were used to examine the effects of puerarin on DEX-induced keratinocyte proliferation and migration and the mechanisms of its action. Puerarin, when applied topically, accelerated the wound closure rate, increased the density of the capillaries, and upregulated the level of collagen fibers and TGF-β in the wound sites compared to the DEX-treated mice. Puerarin promoted the proliferation and migration of keratinocytes by activating the ERK and Akt signaling pathways in DEX-treated HaCaT cells. In conclusion, puerarin could be effective in reversing delayed and disrupted wound healing associated with DEX treatments.

Vitamin D Inhibits IL-22 Production Through a Repressive Vitamin D Response Element in the il22 Promoter.

Th22 cells constitute a recently described CD4+ T cell subset defined by its production of interleukin (IL)-22. The action of IL-22 is mainly restricted to epithelial cells. IL-22 enhances keratinocyte proliferation but inhibits their differentiation and maturation. Dysregulated IL-22 production has been associated to some inflammatory skin diseases such as atopic dermatitis and psoriasis. How IL-22 production is regulated in human T cells is not fully known. In the present study, we identified conditions to generate Th22 cells that do not co-produce IL-17 from naïve human CD4+ T cells. We show that in addition to the transcription factors AhR and RORγt, the active form of vitamin D3 (1,25(OH)2D3) regulates IL-22 production in these cells. By studying T cells with a mutated vitamin D receptor (VDR), we demonstrate that the 1,25(OH)2D3-induced inhibition of il22 gene transcription is dependent on the transcriptional activity of the VDR in the T cells. Finally, we identified a vitamin D response element (VDRE) in the il22 promoter and demonstrate that 1,25(OH)2D3-VDR directly inhibits IL-22 production via this repressive VDRE.

RPL22 Overexpression Promotes Psoriasis-Like Lesion by Inducing Keratinocytes Abnormal Biological Behavior.

BackgroundKeratinocytes of psoriasis have anti-apoptotic properties including delayed apoptosis process, accelerated proliferation metabolism and postponed differentiation process. However, the specific mechanism leading to the abnormal biological behavior of keratinocytes remains unclear.ObjectivesWe investigated the role of increased RPL22 expression in regulating the abnormal biological behavior of keratinocytes and the mechanism of regulation of RPL22 expression in skin lesions of psoriatic patients.MethodsWe examined clinical samples and utilized cytokine-induced cell and IMQ-treated mouse models. We determined the expression and functions of RPL22 in vitro and in vivo.ResultsWe showed that RPL22 expression was significantly increased in the skin lesions of psoriasis patients and IMQ-treated psoriatic-like mice. Such increased expression is attributed to hyperacetylation of histone H3K27 in the promoter region of RPL22. Interestingly, overexpression of RPL22 enhanced keratinocyte proliferation by increasing cyclinD1 expression and accelerated CD4+T cells recruitment via upregulating CXCL10 expression. Finally, we demonstrated that RPL22 overexpression promoted psoriasiform phenotypes in IMQ-induced mouse skins.ConclusionsThese findings suggested that RPL22 regulates keratinocytes abnormal biological behavior and contributes to the development of psoriatic phenotypes. Thus, RPL22 might be a novel potential molecular target for treatment of psoriasis.

Possible role of epiregulin from dermal fibroblasts in the keratinocyte hyperproliferation of psoriasis.

Psoriasis, an immune-mediated inflammatory disease, is characterized by keratinocyte hyperproliferation. Tumor necrosis factor (TNF)-α, interleukin (IL)-23, and IL-17A play critical roles in the pathogenesis of psoriasis. IL-17A secreted by T-helper 17 acts more directly against keratinocytes than TNF-α or IL-23 do. Regarding the receptors of cytokines, fibroblasts also express receptors against IL-17A and TNF-α, and induce the production of growth factors. Epiregulin (EREG), an epidermal growth factor receptor ligand, is produced by both keratinocytes and fibroblasts. EREG enhances keratinocyte proliferation and differentiation. We hypothesized that fibroblasts stimulated with IL-17A and/or TNF-α may play a role in epidermal hyperproliferation through the production of epidermal growth factors in psoriasis. The mRNA expression of EREG was found to be significantly upregulated by co-stimulation with IL-17A and TNF-α (mean, 49.2-fold). Furthermore, the stimulation with TNF-α alone, but not IL-17A alone, induced significant increases. Immunofluorescent staining demonstrated that the protein expression level of EREG was also increased in fibroblasts stimulated with these cytokines. Stimulation with EREG significantly enhanced keratinocyte proliferation in vitro. In human psoriatic patients' skin, immunofluorescence staining of EREG showed significantly high intensity in the dermis of lesional skin. In conclusion, cytokine stimulation with TNF-α and IL-17A induces the overexpression of EREG from dermal fibroblasts in the lesional skin of psoriasis, and plays a role in epidermal hyperproliferation.

The role of ozonated Aloe vera oil in full-thickness skin defects: Macrophage count and epithelization length parameter

Background: Aloe vera has been reported to enhance keratinocyte proliferation and migration, and thereby accelerate wound healing. Ozone therapy is an alternative medicine with disinfecting properties and strong oxidative stress induction capacity. This study aimed to evaluate the effect of Aloe vera oil provided with different dosages of ozone in accelerating the healing rate comparing two-phases; inflammation (day 3) and proliferation (day 7) of full-thickness defect wounds in Sprague Dawley rats as an adjuvant treatment based on macrophage count and new epithelialization length. Methods: We conducted a study using a post-test only control group design, where a total of 50 Sprague Dawley rats were randomized into ten groups. Two control groups were administered Aloe vera oil (P1, P6), while gentamicin ointment was used in the other control group (P2, P7). Ozonated Aloe vera oil dose was used: 600 mg/ml (P3,P8), 1200 mg/ml (P4,P9), and 1800 mg/ml (P5,P10). Groups P1, P2, P3, P4, P5 were terminated on the 3rd day, while P6, P7, P8, P9, P10 were evaluated on the 7th day. Macrophage counts were assessed using a 100x magnification microscope, through hematoxylin-eosin (HE) staining, and paraffin block with Masson trichrome staining was used to measure the new epithelialization length. Results: There were significant differences in the macrophage count on day three between the group-administered gentamicin (P2) and 1800 mg/ml ozonated Aloe vera oil (P5) (79.96;131.96, p&lt;0,05). The new epithelialization length significantly increased in the group provided with wound treatment up to day 7, using 1800 mg/ml ozonated Aloe vera oil (P10), compared to non-ozonated Aloe vera (P6) and the gentamicin therapy (P7) (1160.88 µm; 1367.64; 2451.40 μm, p&lt;0,05). Conclusions: The application of ozonated Aloe vera oil to full-thickness skin defects in Sprague Dawley rats resulted in a higher macrophage count and longer new epithelialization length than in controls.

A G-protein coupled receptor 39 agonist stimulates proliferation of keratinocytes via an ERK-dependent pathway

Keratinocyte proliferation serves as a crucial process in skin wound healing. The zinc-sensing G-protein coupled receptor 39 (GPR39), which is highly expressed in keratinocytes, has been shown to promote skin wound healing. The aim of this study was to investigate the effect of GPR39 activation on proliferation of keratinocytes and its underlying mechanism using immortalized human keratinocytes (HaCaT) as an in vitro model. GPR39 was functionally expressed in HaCaT cells. BrdU proliferation assays showed that treatment with GPR39 agonist TC-G 1008 (100 nM and 1 μM) increased cell proliferation. TC-G 1008 also enhanced ERK phosphorylation in time- and concentration-dependent manners. This effect was suppressed by co-treatment with wortmannin (PI3K inhibitor) and U0126 (MKK inhibitor). Of note, neither inhibition of Gαq-phospholipase C (PLC)-[Ca2+]i nor Gαs-PKA pathway affected GPR39 stimulation-induced ERK phosphorylation. Similarly, barbadin, an inhibitor of G-protein-independent β-arrestin pathway, did not suppress ERK phosphorylation induced by GPR39 activation. Of particular importance, wortmannin, U0126, and FR180204 (ERK inhibitor) abrogated the effect of TC-G 1008-induced cell proliferation. Taken together, this study reveals novel insights into the role of GPR39 in regulating keratinocyte proliferation via a PI3K-MKK-ERK-dependent mechanism. GPR39 agonists may be used in enhancing keratinocyte proliferation, which may be beneficial for the cutaneous wound treatment.

Overexpression of the Oral Mucosa-Specific microRNA-31 Promotes Skin Wound Closure.

Wounds within the oral mucosa are known to heal more rapidly than skin wounds. Recent studies suggest that differences in the microRNAome profiles may underlie the exceptional healing that occurs in oral mucosa. Here, we test whether skin wound-healing can be accelerating by increasing the levels of oral mucosa-specific microRNAs. A panel of 57 differentially expressed high expresser microRNAs were identified based on our previously published miR-seq dataset of paired skin and oral mucosal wound-healing [Sci. Rep. (2019) 9:7160]. These microRNAs were further grouped into 5 clusters based on their expression patterns, and their differential expression was confirmed by TaqMan-based quantification of LCM-captured epithelial cells from the wound edges. Of these 5 clusters, Cluster IV (consisting of 8 microRNAs, including miR-31) is most intriguing due to its tissue-specific expression pattern and temporal changes during wound-healing. The in vitro functional assays show that ectopic transfection of miR-31 consistently enhanced keratinocyte proliferation and migration. In vivo, miR-31 mimic treatment led to a statistically significant acceleration of wound closure. Our results demonstrate that wound-healing can be enhanced in skin through the overexpression of microRNAs that are highly expressed in the privileged healing response of the oral mucosa.

SEROTONIN AND SEROTONIN DERIVATIVES: NEW APPLICATION FOR VARIOUS SKIN DISORDERS

Objectives In the human body, serotonin is well known as a neurotransmitter that regulates mood, appetite and sleep. However, more than 90% of the serotonin in a human body is generated in gastrointestinal, stored in platelets, circulating whole body exept brain, and contributes to various physiological function. Plants also produce serotonin, and this phyto-serotonin is known to be involved in plant growth, flowering, mature and senescence. The most difference between phyto-serotonin and human serotonin is phyto-serotonin turns to various serotonin derivatives to store in flowers and fruits during mature and senescence. Serotonin derivatives were dramatically increased against pathogen attack. There are 4 types of major serotonin derivates. Among these 4 compounds, Caffeoylserotonin (CaS), Feruloylserotonin (FS) and Coumaroylserotonin (CS) are major components which mainly found from some plant extracts. Almost all human diseases are accompanie/d by ROS generation, so we investigated the antioxidant ability of serotonin derivates to make sure that they have a potential as therapeutic reagent. Findings As a result, serotonin and serotonin derivates were found to have up to 16 fold higher antioxidant levels than Trolox which is the standard material of the antioxidant assay. In addition, CaS and 5-HT have been shown to inhibit protein damage and DNA damage either. Serotonin derivatives promote cell proliferation and migration and inhibit melanogensis and cell apoptosis. Interestingly, 5-HT regulated cell proliferation and cell migration only through ERK/AP-1/MMP9 pathway while additional Akt/NF-κB/MMP9 pathway was involved in effects of CaS. Conclusions These results suggest that CaS can enhance keratinocyte proliferation and migration. Overall, serotonin derivatives might have potential as reagents beneficial for wound closing, cell regeneration and anti-melanogenesis.

The Protein Tyrosine Phosphatase H1 PTPH1 Supports Proliferation of Keratinocytes and is a Target of the Human Papillomavirus Type 8 E6 Oncogene.

Human papillomaviruses (HPV) replicate their DNA in the suprabasal layer of the infected mucosa or skin. In order to create a suitable environment for vegetative viral DNA replication HPV delay differentiation and sustain keratinocyte proliferation that can lead to hyperplasia. The mechanism underlying cell growth stimulation is not well characterized. Here, we show that the E6 oncoprotein of the βHPV type 8 (HPV8), which infects the cutaneous skin and is associated with skin cancer in Epidermodysplasia verruciformis patients and immunosuppressed organ transplant recipients, binds to the protein tyrosine phosphatase H1 (PTPH1), which resulted in increased protein expression and phosphatase activity of PTPH1. Suppression of PTPH1 in immortalized keratinocytes reduced cell proliferation as well as the level of epidermal growth factor receptor (EGFR). Furthermore, we report that HPV8E6 expressing keratinocytes have increased level of active, GTP-bound Ras. This effect was independent of PTPH1. Therefore, HPV8E6-mediated targeting of PTPH1 might result in higher level of EGFR and enhanced keratinocyte proliferation. The HPV8E6-mediated stimulation of Ras may be an additional step to induce cell growth. Our results provide novel insights into the mechanism how βHPVE6 proteins support proliferation of infected keratinocytes, thus creating an environment with increased risk of development of skin cancer particularly upon UV-induced DNA mutations.

Plasminogen/thrombomodulin signaling enhances VEGF expression to promote cutaneous wound healing.

Plasminogen (Plg) and thrombomodulin (TM) are glycoproteins well known for fibrinolytic and anticoagulant functions, respectively. Both Plg and TM are essential for wound healing. However, their significance during the reparative process was separately demonstrated in previous studies. Here, we investigate the interaction between Plg and epithelial TM and its effect on wound healing. Characterization of the wound margin revealed that Plg and TM were simultaneously upregulated at the early stage of wound healing and the two molecules were bound together. In vitro, TM silencing or knockout in keratinocytes inhibited Plg activation. Plg treatment enhanced keratinocyte proliferation and migration, and these actions were abolished by TM antibody. Keratinocyte-expressed vascular endothelial growth factor (VEGF), which presented a dose-response relationship with Plg treatment, can be suppressed by TM silencing. Moreover, treatment with VEGF antibody inhibited Plg-enhanced keratinocyte proliferation and wound recovery. In vivo, TM antibody treatment and keratinocyte-specific TM knockout can impede Plg-enhanced wound healing in mice. In high-glucose environments, Plg-enhanced VEGF expression and wound healing were suppressed due at least in part to downregulation of keratinocyte-expressed TM. Taken together, our findings suggest that activation of Plg/TM signaling may hold therapeutic potential for chronic wounds in diabetic or non-diabetic individuals. KEY MESSAGES: Plg binds to TM in cutaneous wound healing. TM facilitates the activation of Plg to Plm in keratinocytes. Epithelial TM regulates Plg-enhanced wound healing through VEGF expression.

Cell proliferation and migration mechanism of caffeoylserotonin and serotonin via serotonin 2B receptor in human keratinocyte HaCaT cells.

Caffeoylserotonin (CaS), one derivative of serotonin (5-HT), is a secondary metabolite produced in pepper fruits with strong antioxidant activities. In this study, we investigated the effect of CaS on proliferation and migration of human keratinocyte HaCaT cells compared to that of 5-HT. CaS enhanced keratinocyte proliferation even under serum deficient condition. This effect of CaS was mediated by serotonin 2B receptor (5-HT2BR) related to the cell proliferation effect of 5-HT. We also confirmed that both CaS and 5-HT induced G1 progression via 5-HT2BR/ERK pathway in HaCaT cells. However, Akt pathway was additionally involved in upregulated expression levels of cyclin D1 and cyclin E induced by CaS by activating 5-HT2BR. Moreover, CaS and 5-HT induced cell migration in HaCaT cells via 5-HT2BR. However, 5-HT regulated cell migration only through ERK/AP-1/MMP9 pathway while additional Akt/NF-κB/MMP9 pathway was involved in the cell migration effect of CaS. These results suggest that CaS can enhance keratinocyte proliferation and migration. It might have potential as a reagent beneficial for wound closing and cell regeneration.

Optimization and integration of nanosilver on polycaprolactone nanofibrous mesh for bacterial inhibition and wound healing in vitro and in vivo.

Bacterial infection is a major hurdle to wound healing, and the overuse of antibiotics have led to global issue, such as emergence of multidrug-resistant bacteria, even “super bacteria”. On the contrary, nanosilver (NS) can kill bacteria without causing resistant bacterial strains. In this study, NS was simply generated in situ on the polycaprolactone (PCL) nanofibrous mesh using an environmentally benign and mussel-inspired dopamine (DA). Scanning electron microscopy showed that NS uniformly formed on the nanofibers of PCL mesh. Fourier transform infrared spectroscopy revealed the step-by-step preparation of pristine PCL mesh, including DA coating and NS formation, which were further verified by water contact angle changing from hydrophobic to hydrophilic. To optimize the NS dose, the antibacterial activity of PCL/NS against Staphylococcus aureus, Escherichia coli and Acinetobacter baumannii was detected by bacterial suspension assay, and the cytotoxicity of NS was evaluated using cellular morphology observation and Cell Counting Kit-8 (CCK8) assay. Then, inductively coupled plasma atomic emission spectrometry exhibited that the optimized PCL/NS had a safe and sustained silver release. Moreover, PCL/NS could effectively inhibit bacterial infection in an infectious murine full-thickness skin wound model. As demonstrated by the enhanced level of proliferating cell nuclear antigen (PCNA) in keratinocytes and longer length of neo-formed epidermis, PCL/NS accelerated wound healing by promoting re-epithelialization via enhancing keratinocyte proliferation in infectious wounds.