Epidermal growth factor (EGF)- and scatter factor/hepatocyte growth factor (SF/HGF)- mediated keratinocyte migration is coincident with induction of matrix metalloproteinase (MMP)-9

Evaluation of the Treatment Effects of Conditioned Medium from Human Orbital Adipose-Derived Stem Cells in a Corneal Alkali Burn Rabbit Model

Purpose: This study aimed to evaluate the effects of a new treatment-conditioned medium from human orbital adipose-derived stem cells (OASC-CM)-on corneal recovery after alkali burns in a rabbit model. Methods: The corneal alkali burn rabbit model was established and treated with OASC-CM, conditioned medium from human abdominal subcutaneous adipose-derived stem cells (ABASC-CM), and fresh control culture medium (con-CM) three times a day for 7 days, respectively. Subsequently, the treatment effects were evaluated and compared through clinical, histological, immunohistochemical, and cytokine evaluations. Results: Clinically, OASC-CM alleviated corneal opacity and edema and promoted recovery of corneal epithelium defect. Histologically and immunohistochemically, OASC-CM inhibited neovascularization, conjunctivalization, and immuno-inflammatory reaction, while promoting corneal regeneration and rearrangement. Increased secretion of interleukin-10 and inhibited protein levels of cluster of differentiation 45, interferon-γ, and tumor necrosis factor-α were observed in the alkali-burned cornea after OASC-CM treatment, which might be the relevant molecular mechanism. Conclusions: OASC-CM showed significant effects on the recovery of rabbit corneal alkali burns and eliminated immunological and ethical limitations, representing a new option for corneal wound treatment.

Monoclonal antibody cetuximab impairs matrix metalloproteinases 2 and 9, epithelial-mesenchymal transition and cell migration in feline oral squamous cell carcinoma in vitro

Feline oral squamous cell carcinoma (FOSCC) is characterised by invasive and metastatic behaviour and is poorly responsive to current treatments, hence the need for new therapeutic strategies. FOSCC shares molecular targets with human head and neck squamous cell carcinoma (HNSCC), among these the epidermal growth factor receptor. Cetuximab is an anti-epidermal growth factor receptor monoclonal antibody employed in the therapy of HNSCC and, interestingly, previous work in vitro suggested that it displays cytostatic and cytotoxic properties also against FOSCC. With the present study, we aimed at further investigating the effects of cetuximab on invasion and metastasis pathways proven to be relevant in human patients. To this purpose, FOSCC cell lines SCCF1, SCCF2 and SCCF3 were treated with cetuximab for 48/72 h and subjected to Western blot for matrix metalloproteinases-2/9 (MMP-2/9) and epithelial-mesenchymal transition markers vimentin, E-, P- and N-cadherin. Treatment with cetuximab resulted in downregulation of MMP-2/-9 in all of the three cell lines in a dose-dependent manner. Moreover, cetuximab downregulated vimentin and P-cadherin in SCCF1, upregulated E-cadherin whilst downregulating P-/N-cadherins in SCCF2, and impaired P-/N-cadherins in SCCF3. An in vitro scratch test also demonstrated that cetuximab delayed cell migration in SCCF3. These data suggest that cetuximab mitigates invasion and metastasis processes by impairing MMPs and epithelial-mesenchymal transition pathways in FOSCC, indicating that this monoclonal antibody may help to counteract malignant progression and improve the management of locally invasive disease.

Involvement of PAR-2 in the Induction of Cell-Specific Matrix Metalloproteinase-2 by Activated Protein C in Cutaneous Wound Healing

We previously reported that human keratinocytes express protease-activated receptor (PAR)-2 and play an important role in activated protein C (APC)-induced cutaneous wound healing. This study investigated the involvement of PAR-2 in the production of gelatinolytic matrix metalloproteinases (MMP)-2 and -9 by APC during cutaneous wound healing. Full-thickness excisional wounds were made on the dorsum of male C57BL/6 mice. Wounds were treated with APC on days 1, 2, and 3 post-wounding. Cultured neonatal foreskin keratinocytes were treated with APC with or without intact PAR-2 signalling to examine the effects on MMP-2 and MMP-9 production. Murine dermal fibroblasts from PAR-2 knock-out (KO) mice were also assessed. MMP-2 and -9 were measured via gelatin zymography, fluorometric assay, and immunohistochemistry. APC accelerated wound healing in WT mice, but had a negligible effect in PAR-2 KO mice. APC-stimulated murine cutaneous wound healing was associated with the differential and temporal production of MMP-2 and MMP-9, with the latter peaking on day 1 and the former on day 6. Inhibition of PAR-2 in human keratinocytes reduced APC-induced MMP-2 activity by 25~50%, but had little effect on MMP-9. Similarly, APC-induced MMP-2 activation was reduced by 40% in cultured dermal fibroblasts derived from PAR-2 KO mice. This study shows for the first time that PAR-2 is essential for APC-induced MMP-2 production. Considering the important role of MMP-2 in wound healing, this work helps explain the underlying mechanisms of action of APC to promote wound healing through PAR-2.

Nuclear IL-33 Plays an Important Role in EGFR-Mediated Keratinocyte Migration by Regulating the Activation of Signal Transducer and Activator of Transcription 3 and NF-κB

Nuclear IL-33 levels are high at the epidermal edges of skin wounds and facilitate wound healing. However, IL-33-mediated regulation of keratinocyte (KC) biology during wound healing remains poorly understood. During skin-wound healing, KC migration and re-epithelialization are mediated predominantly by EGFR signaling activation and depend on the function of signal transducer and activator of transcription 3 (STAT3). We found that migrating KCs at the leading edges of mouse skin wounds exhibited concomitant induction and nuclear colocalization of IL-33 and phosphorylated STAT3. In cultured human KCs, activation of EGFR signaling caused rapid elevation of nuclear IL-33, which directly interacts with phosphorylated STAT3, promoting STAT3 activation. In vitro KC migration and wound-healing assays revealed that high nuclear IL-33 levels were required for KC migration and wound closure. KC mobility associated with a lack of suprabasal epidermal keratins and extracellular matrix degradation mediated by matrix metalloproteinases (MMPs) control cell migration at the intracellular and extracellular levels, respectively. In EGFR-activated KCs, nuclear IL-33 mediated keratin 1 and 10 downregulation and MMP9 upregulation by promoting STAT3 activation and limited MMP1, MMP3, and MMP10 induction by suppressing NF-κB transactivation. Thus, epidermal nuclear IL-33 is involved in KC migration and wound closure by regulating the STAT3 and NF-κB pathways.

Human Amniotic Membrane Promotes Angiogenesis in an Oxidative Stress Chronic Diabetic Murine Wound Model

Objective: The development of animal models, which adequately replicate the pathophysiology of chronic wounds, has been challenging. In this study, we utilized an oxidative stress (OS) murine model, which was previously developed by our group, to study the effect of a human amniotic membrane (AM) on chronic wound healing. Approach: Forty-five diabetic (genetically obese leptin receptor-deficient mice [db/db]) mice were separated into three groups. Thirty mice received an OS regimen and a 1 - × 1 cm² full-thickness excisional dorsal wound. The wounds were either covered with AM and occlusive dressing (db/db^OS-AM) or occlusive dressing only (db/db^OS). Fifteen mice did not receive the OS regimen, and were covered with AM and occlusive dressing (db/db-AM). The wounds were photographed, and tissue was harvested at various time points. Results: Vascular density was higher in the AM-treated groups (db/db^OS-AM: 34 ± 12; db/db-AM: 37 ± 14; vs. db/db^OS: 19 ± 9 cluster of differentiation 31 [CD31⁺]/high power field [HPF] photograph; p = 0.04 and p = 0.003). Vessel maturity was lowest in the db/db^OS group (21% ± 4%; vs. db/db^OS-AM: 38% ± 10%, p = 0.004; db/db-AM: 40% ± 11%, p = 0.0005). Leukocyte infiltration was higher in the AM groups (db/db^OS-AM: 15 ± 4; db/db-AM: 16 ± 4 vs. db/db^OS: 8 ± 3 lymphocyte common antigen [CD45⁺]/HPF; p = 0.005 and p = 0.06). AM upregulated various proangiogenic factors, including vascular endothelial growth factor (VEGF), and downregulated genes involved in chronicity, such as osteopontin, as visualized through proteome analysis and western blotting. Cell death was lower in the AM groups (db/db^OS-AM: 28 ± 10, db/db-AM: 7 ± 5 vs. db/db^OS: 17% ± 9% Terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling [TUNEL⁺]; p = 0.03 and p < 0.0001). Innovation: This study offers new insight on the mechanisms of action of human AM in chronic wound healing. Conclusion: AM treatment promoted healing in mice with complex chronic wounds. The AM stimulated angiogenesis through upregulation of proangiogenic factors, improving the wound milieu by increasing leukocyte and growth factor delivery and decreasing cell death.

Antioxidant, Wound Healing Potential and In Silico Assessment of Naringin, Eicosane and Octacosane

1. Diabetic chronic wounds, mainly foot ulcers, constitute one of the most common complications of poorly managed diabetes mellitus. The most typical reasons are insufficient glycemic management, latent neuropathy, peripheral vascular disease, and neglected foot care. In addition, it is a common cause of foot osteomyelitis and amputation of the lower extremities. Patients are admitted in larger numbers attributable to chronic wounds compared to any other diabetic disease. In the United States, diabetes is currently the most common cause of non-traumatic amputations. Approximately five percent of diabetics develop foot ulcers, and one percent require amputation. Therefore, it is necessary to identify sources of lead with wound-healing properties. Redox imbalance due to excessive oxidative stress is one of the causes for the development of diabetic wounds. Antioxidants have been shown to decrease the progression of diabetic neuropathy by scavenging ROS, regenerating endogenous and exogenous antioxidants, and reversing redox imbalance. Matrix metalloproteinases (MMPs) play vital roles in numerous phases of the wound healing process. Antioxidant and fibroblast cell migration activity of Marantodes pumilum (MP) crude extract has previously been reported. Through their antioxidant, epithelialization, collagen synthesis, and fibroblast migration activities, the authors hypothesise that naringin, eicosane and octacosane identified in the MP extract may have wound-healing properties. 2. The present study aims to identify the bioactive components present in the dichloromethane (DCM) extract of M. pumilum and evaluate their antioxidant and wound healing activity. Bioactive components were identified using LCMS, HPTLC and GCMS. Excision wound on STZ-induced diabetic rat model, human dermal fibroblast (HDF) cell line and colorimetric antioxidant assays were used to evaluate wound healing and antioxidant activities, respectively. Molecular docking and pkCMS software would be utilised to predict binding energy and affinity, as well as ADME parameters. 3. Naringin (NAR), eicosane (EIC), and octacosane (OCT) present in MP displayed antioxidant action and wound excision closure. Histological examination HDF cell line demonstrates epithelialization, collagen production, fibroblast migration, polymorphonuclear leukocyte migration (PNML), and fibroblast movement. The results of molecular docking indicate a substantial attraction and contact between MMPs. pkCMS prediction indicates inadequate blood-brain barrier permeability, low toxicity, and absence of hepatotoxicity. 4. Wound healing properties of (NEO) naringin, eicosane and octacosane may be the result of their antioxidant properties and possible interactions with MMP.

MMP9 secreted from mononuclear cell quality and quantity culture mediates STAT3 phosphorylation and fibroblast migration in wounds

Introduction

Intractable ulcers may ultimately lead to amputation. To promote wound healing, researchers developed a serum-free ex vivo peripheral blood mononuclear cell quality and quantity culture (MNC-QQc) as a source for cell therapy. In mice, pigs, and even humans, cell therapy with MNC-QQc reportedly yields a high regenerative efficacy. However, the mechanism of wound healing by MNC-QQc cells remains largely unknown. Hence, using an in vitro wound healing model, this study aimed to investigate MNC-QQc cells and the migratory potential of dermal fibroblasts.

Methods

After separation from a 50 mL blood sample from healthy individuals, mononuclear cells were cultured for 7 days in a serum-free ex vivo expansion system with five different cytokines (MNC-QQc method). The effects of MNC-QQc cells on human dermal fibroblast migration were observed by scratch assay. An angiogenesis array screened the MNC-QQc cell supernatant for proteins related to wound healing. Finally, fibroblast migration was confirmed by observing the intracellular signal transduction pathways via Western blot.

Results

The migration of fibroblasts co-cultured with MNC-QQc cells increased by matrix metallopeptidase-9 (MMP9) secretion, as suggested by the angiogenesis array. Furthermore, the phosphorylation of signal transducer and activator of transcription 3 (STAT3) in fibroblast/MNC-QQc cell co-culture and fibroblast culture with added recombinant human MMP9 protein increased. When fibroblasts were cultured with either an MMP9 inhibitor or a STAT3 inhibitor, both fibroblast migration and STAT3 phosphorylation were significantly suppressed.

Conclusions

MNC-QQc cells promote wound healing by the secretion of MMP9, which induces fibroblast migration via the STAT3 signaling pathway.

Strategy for Treatment of Infected Diabetic Foot Ulcers

Diabetic foot ulcers (DFUs) are chronic wounds that develop in 30% of diabetic patients. In DFUs, the normal wound healing process consisting of inflammation, angiogenesis, and extracellular matrix (ECM) remodeling is dysregulated and stalled. Upon injury, neutrophils and monocytes arrive at the wound and secrete matrix metalloproteinase (MMP)-8 and reactive oxygen species (ROS). ROS activates nuclear factor kappa beta (NF-κB), which upregulates MMP-9. Monocytes become macrophages, secreting tumor growth factor (TGF)-β1 and vascular endothelial growth factor (VEGF) for angiogenesis, resulting in remodeling of the ECM. MMP-9 cleaves laminin for keratinocyte migration. MMP-8 is beneficial for remodeling the ECM and healing the wound. In DFUs, the excess unregulated MMP-9 is detrimental, destroying the ECM and preventing the wound from healing. DFUs are typically infected, many with biofilm-producing bacteria that are resistant to antibiotics. Infection increases the time for wound healing and the likelihood for a lower-limb amputation. Despite the use of antibiotics, amputations occur in 24.5% of patients with DFUs. Clearly, new strategies for treatment of DFUs are needed. With the use of an affinity resin that binds exclusively to the active forms of MMPs and proteomics, we identified two proteinases, MMP-8 and MMP-9, in wounds of diabetic mice and diabetic humans. With the use of selective inhibitors, gene ablation of MMP-9, and exogenous application of MMP-8, we demonstrated that MMP-8 is beneficial to wound repair and that MMP-9 prevents the diabetic wound from healing. Our research has shown that infection increases active MMP-9, increasing inflammation and decreasing angiogenesis. As a result, infected diabetic wounds take a longer time to heal than uninfected ones. We found that active MMP-9 and NF-κB increased in human DFUs with wound severity and infection. The best strategy for treatment of DFUs is to selectively inhibit the detrimental proteinase MMP-9 without affecting the beneficial MMP-8 so that the body can repair the wound. Lead optimization of the thiirane class of inhibitors led to the discovery of (R)-ND-336, a potent (19 nM) and selective (450-fold) MMP-9 inhibitor. (R)-ND-336 accelerated wound healing in diabetic mice by decreasing ROS and NF-κB, lowering inflammation, and increasing angiogenesis. (R)-ND-336 in combination with the antibiotic linezolid improved wound healing in infected diabetic mice by inhibiting MMP-9, which mitigated macrophage infiltration and increased angiogenesis, thereby restoring the normal wound healing process.

Development of novel microenvironments for promoting enhanced wound healing

PURPOSE OF REVIEW

Nonhealing wounds are a significant issue facing the healthcare industry. Materials that modulate the wound microenvironment have the potential to improve healing outcomes.

RECENT FINDINGS

A variety of acellular and cellular scaffolds have been developed for regulating the wound microenvironment, including materials for controlled release of antimicrobials and growth factors, materials with inherent immunomodulative properties, and novel colloidal-based scaffolds. Scaffold construction methods include electrospinning, 3D printing, decellularization of extracellular matrix, or a combination of techniques. Material application methods include layering or injecting at the wound site.

SUMMARY

Though these techniques show promise for repairing wounds, all material strategies thus far struggle to induce regeneration of features such as sweat glands and hair follicles. Nonetheless, innovative technologies currently in the research phase may facilitate future attainment of these features. Novel methods and materials are constantly arising for the development of microenvironments for enhanced wound healing.

Silver Decorated Mesoporous Carbons for the Treatment of Acute and Chronic Wounds, in a Tissue Regeneration Context

INTRODUCTION

Silver decorated mesoporous carbons are interesting systems that may offer effective solutions for advanced wound care products by combining the well-known anti-microbial activity of silver nanoparticles with the versatile properties of ordered mesoporous carbons. Silver is being used as a topical antimicrobial agent, especially in wound repair. However, while silver shows bactericidal properties, it is also cytotoxic at high concentrations. Therefore, the incorporation of silver into ordered mesoporous carbons allows to exploit both silver's biological effects and mesoporous carbons' biocompatibility and versatility with the purpose of conceiving silver-doped materials in light of the growing health concern in wound care.

METHODS

The wound healing potential of an ordered mesoporous carbon also doped with two different loadings of silver nanoparticles (2 wt% and 10 wt%), was investigated through a biological assessment study based on different assays (cell viability, inflammation, antibacterial tests, macrophage-conditioned fibroblast and human keratinocyte cell cultures).

RESULTS

The results show silver-doped ordered mesoporous carbons to positively condition cell viability, with a cell viability percentage >70% even for 10 wt% Ag, to modulate the expression of inflammatory cytokines and of genes involved in tissue repair (KRT6a, VEGFA, IVN) and remodeling (MMP9, TIMP3) in different cell systems. Furthermore, along with the biocompatibility and the bioactivity, the silver-doped ordered mesoporous carbons still retain an antibacterial effect, as shown by a maximum of 13.1% of inhibited area in the Halo test. The obtained results clearly showed that the silver-doped ordered mesoporous carbons exhibit both good biocompatibility and antibacterial effect with enhanced re-epithelialization, angiogenesis promotion and tissue regeneration.

DISCUSSION

These findings suggest that the exceptional properties of silver-doped ordered mesoporous carbons could be exploited in the treatment of acute and chronic wounds and that such carbon materials could be potential candidates for use in medical devices for wound healing purposes, in particular, the 10 wt% loading, as the results showed to be the most effective.

Collagen sponge scaffolds containing growth factors for the functional regeneration of tracheal epithelium

Tracheal epithelia have barrier and mucociliary clearance functions that prevent invasion of extraneous particles and infectious materials. Hence, following tracheal reconstructions, functional and morphological regeneration of epithelia is required to prevent respiratory declines and infectious diseases. Although growth factors (GFs) promote the regeneration of tracheal epithelial morphologies, it remains unclear whether tracheal grafts containing GFs are beneficial for regeneration of tracheal epithelial functions. Thus, we fabricated collagen sponge scaffolds containing insulin-like GF-1 (IGF-1) and the basic fibroblast, hepatocyte, and epidermal GFs (bFGFs, HGFs, and EGFs, respectively), and we evaluated the effects of the grafts on the functional regeneration of tracheal epithelia. Partial tracheal defects were imposed surgically, and collagen sponges containing IGF-1, bFGF, HGF, or EGF were then transplanted to defect sites. Subsequent immunofluorescence studies suggested that EGF and bFGF contribute to regular distributions of tight junction molecules, and tracer permeability assays suggested that EGF and bFGF promote regeneration of barrier function. Increased ciliogenesis was also observed using scanning electron microscopy in reconstructed regions treated with EGF- and bFGF-supplemented collagen sponges. However, bFGF-supplemented collagen sponges led to greater microsphere transport than did EGF-supplemented sponges. The present data suggested that collagen sponge scaffold containing bFGF promotes functional regeneration of tracheal epithelial tissues.

HGF/c-MET Signaling in Melanocytes and Melanoma

Hepatocyte growth factor (HGF)/ mesenchymal-epithelial transition factor (c-MET) signaling is involved in complex cellular programs that are important for embryonic development and tissue regeneration, but its activity is also utilized by cancer cells during tumor progression. HGF and c-MET usually mediate heterotypic cell–cell interactions, such as epithelial–mesenchymal, including tumor–stroma interactions. In the skin, dermal fibroblasts are the main source of HGF. The presence of c-MET on keratinocytes is crucial for wound healing in the skin. HGF is not released by normal melanocytes, but as melanocytes express c-MET, they are receptive to HGF, which protects them from apoptosis and stimulates their proliferation and motility. Dissimilar to melanocytes, melanoma cells not only express c-MET, but also release HGF, thus activating c-MET in an autocrine manner. Stimulation of the HGF/c-MET pathways contributes to several processes that are crucial for melanoma development, such as proliferation, survival, motility, and invasiveness, including distant metastatic niche formation. HGF might be a factor in the innate and acquired resistance of melanoma to oncoprotein-targeted drugs. It is not entirely clear whether elevated serum HGF level is associated with low progression-free survival and overall survival after treatment with targeted therapies. This review focuses on the role of HGF/c-MET signaling in melanoma with some introductory information on its function in skin and melanocytes.

In vitro molecular study of wound healing using biosynthesized bacteria nanocellulose/silver nanocomposite assisted by bioinformatics databases

Background

In recent years, bacterial nanocellulose (BNC) based nanocomposites have been developed to promote healing property and antibacterial activity of BNC wound dressing. Molecular study can help to better understanding about interaction of genes and pathways involved in healing progression.

Objectives

The aim of this study was to prepare bacterial nanocellulose/silver (BNC/Ag) nanocomposite films as ecofriendly wound dressing in order to assess their physical, cytotoxicity and antimicrobial properties. The in vitro molecular study was performed to evaluate expression of genes involved in healing of wounds after treatment with BNC/Ag biofilms.

Study design materials and methods

Silver nanoparticles were formed by using Citrullus colocynthis extract within new isolated bacterial nanocellulose (BNC) RM1. The nanocomposites were characterized using X-ray diffraction, Fourier transform infrared, and field emission scanning electron microscopy. Besides, swelling property and Ag release profile of the nanocomposites were studied. The ability of nanocomposites to promote wound healing of human dermal fibroblast cells in vitro was studied. Bioinformatics databases were used to identify genes with important healing effect. Key genes which interfered with healing were studied by quantitative real time PCR.

Results

Spherical silver nanoparticles with particle size ranging from 20 to 50 nm were synthesized and impregnated within the structure of BNC. The resulting nanocomposites showed significant antibacterial activities with inhibition zones ranging from 7±0.25 to 16.24±0.09 mm against skin pathogenic bacteria. Moreover, it was compatible with human fibroblast cells (HDF) and could promote in vitro wound healing after 48h. Based on bioinformatics databases, the genes of TGF-β1, MMP2, MMP9, CTNNB1, Wnt4, hsa-miR-29b-3p and hsa-miR-29c-3p played important role in wound healing. The nanocomposites had an effect in expression of the genes in healing. Thus, the BNC/Ag nanocomposite can be used to heal wound in a short period and simple manner.

Conclusion

This eco-friendly nanocomposite with excellent antibacterial activities and healing property confirming its utility as potential wound dressings.

Increased GPNMB, phospho-ERK1/2, and MMP-9 in cystic fibrosis in association with reduced arylsulfatase B

BACKGROUND

GPNMB was increased in a CF gene array and in Arylsulfatase B (ARSB; N-acetylgalactosamine-4-sulfatase)-null mice, consistent with previous reports that ARSB is reduced in cystic fibrosis (CF). Implications of GPNMB increase in CF are unknown.

METHODS

GPNMB levels were determined in serum and circulating leukocytes from CF patients and healthy controls. GPNMB binding with β-1 integrin and measurements of phospho-ERK1/2 and MMP-9 in CFTR-uncorrected, CFTR-corrected, and normal human bronchial epithelial cells (BEC) were determined, following ARSB and GPNMB knockdown, and treatment with RGD peptide, and ERK phosphorylation inhibitor.

RESULTS

GPNMB was markedly increased in CF patients compared to controls (p < 0.0001, unpaired t-test, two-tailed). Silencing GPNMB, treatment with excess RGD peptide, and treatment with ERK phosphorylation inhibitor blocked ARSB silencing-induced increases in MMP-9 in the normal BEC.

CONCLUSIONS

Findings suggest that decline in ARSB activity caused by decline in CFTR function leads to increased GPNMB, which may contribute to organ dysfunction in CF by increased MMP-9 expression.

Stem cells in middle ear cholesteatoma contribute to its pathogenesis

Cholesteatoma is a potentially life-threatening middle ear lesion due to the formation of an inflamed ectopic mass of keratinizing squamous epithelium. Surgical removal remains the only treatment option, emphasizing the need to gain a better understanding of this severe disease. We show for the first time that stem cells residing in cholesteatoma tissue contribute to disease progression. Cells expressing the “stemness” markers Nestin and S100B were detected in middle ear cholesteatoma and auditory canal skin. Isolated Nestin + /S100B + -cells showed the capability for self-renewal, neurosphere formation and differentiation into mesodermal and ectodermal cell types. Compared to auditory canal skin stem cells middle ear cholesteatoma-derived stem cells displayed an enhanced susceptibility to inflammatory stimuli, and this suggested a possible contribution to the inflammatory environment in cholesteatoma tissue. Cholesteatoma derived stem cells were able to differentiate into keratinocyte-like cells using factors mimicking the microenvironment of cholesteatoma. Our findings demonstrate a new perspective on the pathogenesis of cholesteatoma and may lead to new treatment strategies for this severe middle ear lesion.

Galectin-3: One Molecule for an Alphabet of Diseases, from A to Z

Galectin-3 (Gal-3) regulates basic cellular functions such as cell-cell and cell-matrix interactions, growth, proliferation, differentiation, and inflammation. It is not surprising, therefore, that this protein is involved in the pathogenesis of many relevant human diseases, including cancer, fibrosis, chronic inflammation and scarring affecting many different tissues. The papers published in the literature have progressively increased in number during the last decades, testifying the great interest given to this protein by numerous researchers involved in many different clinical contexts. Considering the crucial role exerted by Gal-3 in many different clinical conditions, Gal-3 is emerging as a new diagnostic, prognostic biomarker and as a new promising therapeutic target. The current review aims to extensively examine the studies published so far on the role of Gal-3 in all the clinical conditions and diseases, listed in alphabetical order, where it was analyzed.

On-demand dissolution of modular, synthetic extracellular matrix reveals local epithelial-stromal communication networks

Methods to parse paracrine epithelial-stromal communication networks are a vital need in drug development, as disruption of these networks underlies diseases ranging from cancer to endometriosis. Here, we describe a modular, synthetic, and dissolvable extracellular matrix (MSD-ECM) hydrogel that fosters functional 3D epithelial-stromal co-culture, and that can be dissolved on-demand to recover cells and paracrine signaling proteins intact for subsequent analysis. Specifically, synthetic polymer hydrogels, modified with cell-interacting adhesion motifs and crosslinked with peptides that include a substrate for cell-mediated proteolytic remodeling, can be rapidly dissolved by an engineered version of the microbial transpeptidase Sortase A (SrtA) if the crosslinking peptide includes a SrtA substrate motif and a soluble second substrate. SrtA-mediated dissolution affected only 1 of 31 cytokines and growth factors assayed, whereas standard protease degradation methods destroyed about half of these same molecules. Using co-encapsulated endometrial epithelial and stromal cells as one model system, we show that the dynamic cytokine and growth factor response of co-cultures to an inflammatory cue is richer and more nuanced when measured from SrtA-dissolved gel microenvironments than from the culture supernate. This system employs accessible, reproducible reagents and facile protocols; hence, has potential as a tool in identifying and validating therapeutic targets in complex diseases.

Protective effects of Polypodium leucotomos extract against UVB-induced damage in a model of reconstructed human epidermis

BACKGROUND

Polypodium leucotomos (PL) exerts potent antioxidant, photo-protective, and immune-modulatory activities. A reconstructed human epidermis (RHE) (Episkin) is a suitable model for the evaluation of acute UV-induced cell damage. No data regarding the photo-protective action of PL in this model are available.

PURPOSE

We evaluated the effects of PL on the prevention of UVB-induced cell damage assessing sunburn cells, CPD formation, p53, Ki-67, p21 expression, and epidermal growth factor (EGF) production.

MATERIALS & METHODS

RHE was incubated in standard conditions. PL was topically applied at the concentration of 2 mg/cm² , immediately before UVB exposition. UVB exposition (300 mJ/cm² ) was performed using a dedicated UVB lamp. Irradiated samples without PL and non-irradiated samples were used as positive and negative controls. Expression of p53, p21, and Ki-67 was evaluated with immune-histochemical methods. CPD were measured using a monoclonal antibody.

RESULTS

PL significantly reduced sunburned cells (-80%) in comparison with positive control. PL significantly prevented the increase in EGF production at tested times. PL significantly reduced the p53 (-80%), p21 (-84%), and Ki-67 (-48%) positive cells. Finally, PL prevented the formation of CPD (0% vs. 20% positive cells).

CONCLUSION

In this model, PL has shown to prevent UVB cell damage, the upregulation of proliferating proteins, and fully blocking the formation of CPD.

Heparin cross-linked collagen sponge scaffolds improve functional regeneration of rat tracheal epithelium

Tracheal epithelial cells maintain airway homeostasis by mediating mucociliary clearance. Following tracheal reconstruction, timely epithelial regeneration is required to prevent respiratory compromise and infectious diseases. To achieve rapid tracheal epithelial regeneration, a heparin cross-linked collagen sponge containing fibroblast growth factor-2 (FGF-2) was prepared as a graft for tracheal reconstruction. The heparin cross-linked sponge exhibited a high FGF-2 retaining capacity, and tracheal epithelial and mesenchymal cells cultured in this sponge containing FGF-2 showed high proliferative capacities. Subsequently, heparin-free collagen sponge scaffolds (C/F scaffold) and collagen sponge scaffolds cross-linked with 10 μg/ml heparin retained FGF-2 (C/H10/F scaffold), and were transplanted into rats with tracheal defects. Invasion of both epithelial and non-epithelial cells was greater in rats treated with the C/H10/F scaffold at 1 week post-transplantation than in rats treated with the C/F scaffold. Moreover, at 2 weeks after transplantation, improved cilia formation was observed in the C/H10/F scaffold group, with higher motility and more potent posterior-anterior flow generation than in the C/F scaffold group. These results suggest that heparin improves functional regeneration of tracheal epithelium. Copyright © 2017 John Wiley & Sons, Ltd.

Gamma secretase inhibitor impairs epithelial-to-mesenchymal transition induced by TGF-β in ovarian tumor cell lines

Ovarian cancer is characterized by being highly metastatic, a feature that represents the main cause of failure of the treatment. This study investigated the effects of γ-secretase inhibition on the TGF-β-induced epithelial-mesenchymal transition (EMT) process in ovarian cancer cell lines. SKOV3 cells incubated in the presence of TGF-β showed morphological and biochemical changes related to EMT, which were blocked by co-stimulation with TGF-β and the γ-secretase inhibitor DAPT. In SKOV3 and IGROV1 cells, the co-stimulation blocked the cadherin switch and the increase in the transcription factors Snail, Slug, Twist and Zeb1 induced by TGF-β. DAPT impaired the translocation of phospho-β-catenin to the inner cell compartment observed in TGF-β-treated cells, but was not able to block the induction at protein level induced by TGF-β. Moreover, the inhibitor blocked the increased cell migration and invasiveness ability of both cell lines induced by TGF-β. Notch target genes (Hes1 and Hey1) were induced by TGF-β, decreased by DAPT treatment and remained low in the presence of both stimuli. However, DAPT alone caused no effects on most of the parameters analyzed. These results demonstrate that the γ-secretase inhibitor used in this study exerted a blockade on TGF-β-induced EMT in ovarian cancer cells.

Tobacco toxins deposited on surfaces (third hand smoke) impair wound healing

Third hand smoke (THS) is the accumulation of second hand smoke (SHS) toxins on surfaces in homes, cars, clothing and hair of smokers. It is known that 88M US nonsmokers ≥3 years old living in homes of smokers are exposed to THS toxicants and show blood cotinine levels of ≥0.05 ng/ml, indicating that the toxins are circulating in their circulatory systems. The goal of the present study is to investigate the mechanisms by which THS causes impaired wound healing. We show that mice living under conditions that mimic THS exposure in humans display delayed wound closure, impaired collagen deposition, altered inflammatory response, decreased angiogenesis, microvessels with fibrin cuffs and a highly proteolytic wound environment. Moreover, THS-exposed mouse wounds have high levels of oxidative stress and significantly lower levels of antioxidant activity leading to molecular damage, including protein nitration, lipid peroxidation and DNA damage that contribute to tissue dysfunction. Furthermore, we show that elastase is elevated, suggesting that elastin is degraded and the plasticity of the wound tissue is decreased. Taken together, our results lead us to conclude that THS toxicants delay and impair wound healing by disrupting the sequential processes that lead to normal healing. In addition, the lack of elastin results in loss of wound plasticity, which may be responsible for reopening of wounds.

Overexpression of PRAS40(T246A) in the Proliferative Compartment Suppresses mTORC1 Signaling, Keratinocyte Migration, and Skin Tumor Development

The proline-rich Akt (v-akt murine thymoma viral oncogene homolog 1) substrate of 40 kDa (PRAS40), an inhibitory component of the mTORC1 complex, was identified as an Akt substrate through phosphorylation at Thr246. Phosphorylation at this site releases PRAS40 from the mammalian/mechanistic target of rapamycin complex 1 (mTORC1) complex allowing increased activity. Targeted expression of a mutant form of PRAS40 (PRAS40(T246A)) in basal keratinocytes of mouse epidermis (BK5.PRAS40(T246A) mice) has allowed further examination of mTORC1-specific signaling in epithelial carcinogenesis. BK5.PRAS40(T246A) mice were resistant to 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced epidermal hyperproliferation and skin tumor development. In transgenic mice, PRAS40(T246A) remained bound to raptor in keratinocytes even after treatment with TPA, consistent with reduced mTORC1 signaling and altered levels of cell cycle proteins. BK5.PRAS40(T246A) mice also displayed attenuated skin inflammation in response to TPA. Inhibition of mTORC1 in keratinocytes significantly inhibited their migration in vitro and, in addition, inhibited 12-O-tetradecanoylphorbol-13-acetate-induced proliferation and migration of bulge-region stem cells in vivo. Furthermore, targeted inhibition of mTORC1 in BK5.PRAS40(T246A) mice resulted in delayed wound healing. Decreased keratinocyte migration and impaired wound healing correlated with altered expression of epithelial-mesenchymal transition (EMT) markers and reduced smad signaling. Collectively, the current data using this unique mouse model provide further evidence that mTORC1 signaling in keratinocytes regulates key events in keratinocyte function and epithelial cancer development.

TNF-α promotes breast cancer cell migration and enhances the concentration of membrane-associated proteases in lipid rafts

Purpose

Tumor progression is associated with cell migration, invasion and metastasis. These processes are accompanied by the activation of specific proteases that are either linked to cellular membranes or are secreted into extracellular spaces. TNF-α is known to play an important role in various aspects of tumor progression. The aim of this work was to assess the effect of TNF-α on the migration of breast cancer cells and, in addition, to assess its association with the location of membrane-associated proteases in lipid rafts.

Methods

Wound scratch healing and Transwell migration assays were used to study the effect of TNF-α on the migration of both hormone-dependent and hormone-independent breast cancer-derived cells, i.e., MCF7 and MDA-MB-231, respectively. The expression and secretion of three matrix metalloproteases, MMP9, MMP2 and MT1-MMP, and two dipeptidyl peptidases, CD26 and FAP-α, was investigated using RT-PCR, Western blotting and gelatin zymography. In addition, activation of the MAPK/ERK signaling pathway was investigated by Western blotting.

Results

We found that a TNF-α-induced enhancement of breast cancer cell migration was accompanied by an increased secretion of MMP9, but not MMP2, into the culture media. We also found that TNF-α upregulated the expression of the dipeptidyl peptidases CD26 and FAP-α in a dose-dependent manner and, in addition, enhanced the concentration of all five proteases in lipid rafts in the breast cancer-derived cells tested, regardless of cell type. Furthermore, we found that TNF-α activated the MAPK/ERK signaling pathway by increasing the ERK1/2 phosphorylation level. Application of the MEK/ERK1/2 inhibitor U-0126 resulted in down-regulation of TNF-α-induced MMP9 secretion and abrogation of the enhanced concentration of proteases in the lipid rafts.

Conclusions

From our results we conclude that TNF-α-induced activation of the MAPK/ERK signaling pathway may promote breast cancer cell migration via both upregulation of MMP9, CD26 and FAP-α and concentration of these proteases, as also MT1-MMP and MMP2, in the lipid rafts. TNF-α may serve as a potential therapeutic target in breast cancers susceptible to TNF-α stimulation.

Perlecan Diversely Regulates the Migration and Proliferation of Distinct Cell Types in vitro

Perlecan is a multifunctional component of the extracellular matrix. It shows different effects on distinct cell types, and therefore it is thought to show potential for therapies targeting multiple cell types. However, the full range of multifunctionality of perlecan remains to be elucidated. We cultured various cell types, which were derived from epithelial/endothelial, connective and muscle tissues, in the presence of either antiserum against perlecan or exogenous perlecan, and examined the effects of perlecan on cell migration and proliferation. Cell migration was determined using a scratch assay. Blocking of perlecan by anti-perlecan antiserum inhibited the migration of vascular endothelial cells (VECs) and bone marrow-derived mesenchymal stem cells, and exogenous perlecan added to the culture medium promoted the migration of these cell types. The migration of other cell types was inhibited or was not promoted by exogenous perlecan. Cell proliferation was measured using a water-soluble tetrazolium dye. When cells were cultured at low densities, perlecan blocking inhibited the proliferation of VECs, and exogenous perlecan promoted the proliferation of keratinocytes. In contrast, the proliferation of fibroblasts, pre-adipocytes and vascular smooth muscle cells cultured at low densities was inhibited by exogenous perlecan. When cells were cultured at high densities, perlecan blocking promoted the proliferation of most cell types, with the exception of skeletal system-derived cells (chondrocytes and osteoblasts), which were inhibited by exogenous perlecan. Our results provide an overview of the multiple functions of perlecan in various cell types, and implicate a potential role of perlecan to inhibit undesirable activities, such as fibrosis, obesity and intimal hyperplasia.

Dasatinib Modulates Invasive and Migratory Properties of Canine Osteosarcoma and has Therapeutic Potential in Affected Dogs

BACKGROUND: This investigation sought to elucidate the relationship between hepatocyte growth factor (HGF)–induced metastatic behavior and the tyrosine kinase inhibitors (TKIs) crizotinib and dasatinib in canine osteosarcoma (OS). Preliminary evidence of an apparent clinical benefit from adjuvant therapy with dasatinib in four dogs is described. METHODS: The inhibitors were assessed for their ability to block phosphorylation of MET; reduce HGF-induced production of matrix metalloproteinase (MMP); and prevent invasion, migration, and cell viability in canine OS cell lines. Oral dasatinib (0.75 mg/kg) was tested as an adjuvant therapy in four dogs with OS. RESULTS: Constitutive phosphorylation of MET was detected in two cell lines, and this was unaffected by 20-nM incubation with either dasatinib or crizotinib. Incubation of cell lines with HGF (MET ligand) increased cell migration and invasion in both cell lines and increased MMP-9 activity in one. Dasatinib suppressed OS cell viability and HGF-induced invasion and migration, whereas crizotinib reduced migration and MMP-9 production but did not inhibit invasion or viability. CONCLUSIONS: Invasion, migration, and viability of canine OS cell lines are increased by exogenous HGF. HGF induces secretion of different forms of MMP in different cell lines. The HGF-driven increase in viability and metastatic behaviors we observed are more uniformly inhibited by dasatinib. These observations suggest a potential clinical benefit of adjuvant dasatinib treatment for dogs with OS.

Matrix metalloproteinase 9 modulates collagen matrices and wound repair

Acute and chronic injuries are characterized by leukocyte infiltration into tissues. Although matrix metalloproteinase 9 (Mmp9) has been implicated in both conditions, its role in wound repair remains unclear. We previously reported a zebrafish chronic inflammation mutant caused by an insertion in the hepatocyte growth factor activator inhibitor gene 1 (hai1; also known as spint1) that is characterized by epithelial extrusions and neutrophil infiltration into the fin. Here, we performed a microarray analysis and found increased inflammatory gene expression in the mutant larvae, including a marked increase in mmp9 expression. Depletion of mmp9 partially rescued the chronic inflammation and epithelial phenotypes, in addition to restoring collagen fiber organization, as detected by second-harmonic generation imaging. Additionally, we found that acute wounding induces epithelial cell mmp9 expression and is associated with a thickening of collagen fibers. Interestingly, depletion of mmp9 impaired this collagen fiber reorganization. Moreover, mmp9 depletion impaired tissue regeneration after tail transection, implicating Mmp9 in acute wound repair. Thus, Mmp9 regulates both acute and chronic tissue damage and plays an essential role in collagen reorganization during wound repair.

Three-dimensional spheroid cell culture of umbilical cord tissue-derived mesenchymal stromal cells leads to enhanced paracrine induction of wound healing

Introduction

The secretion of trophic factors by mesenchymal stromal cells has gained increased interest given the benefits it may bring to the treatment of a variety of traumatic injuries such as skin wounds. Herein, we report on a three-dimensional culture-based method to improve the paracrine activity of a specific population of umbilical cord tissue-derived mesenchymal stromal cells (UCX®) towards the application of conditioned medium for the treatment of cutaneous wounds.

Methods

A UCX® three-dimensional culture model was developed and characterized with respect to spheroid formation, cell phenotype and cell viability. The secretion by UCX® spheroids of extracellular matrix proteins and trophic factors involved in the wound-healing process was analysed. The skin regenerative potential of UCX® three-dimensional culture-derived conditioned medium (CM3D) was also assessed in vitro and in vivo against UCX® two-dimensional culture-derived conditioned medium (CM2D) using scratch and tubulogenesis assays and a rat wound splinting model, respectively.

Results

UCX® spheroids kept in our three-dimensional system remained viable and multipotent and secreted considerable amounts of vascular endothelial growth factor A, which was undetected in two-dimensional cultures, and higher amounts of matrix metalloproteinase-2, matrix metalloproteinase-9, hepatocyte growth factor, transforming growth factor β1, granulocyte-colony stimulating factor, fibroblast growth factor 2 and interleukin-6, when compared to CM2D. Furthermore, CM3D significantly enhanced elastin production and migration of keratinocytes and fibroblasts in vitro. In turn, tubulogenesis assays revealed increased capillary maturation in the presence of CM3D, as seen by a significant increase in capillary thickness and length when compared to CM2D, and increased branching points and capillary number when compared to basal medium. Finally, CM3D-treated wounds presented signs of faster and better resolution when compared to untreated and CM2D-treated wounds in vivo. Although CM2D proved to be beneficial, CM3D-treated wounds revealed a completely regenerated tissue by day 14 after excisions, with a more mature vascular system already showing glands and hair follicles.

Conclusions

This work unravels an important alternative to the use of cells in the final formulation of advanced therapy medicinal products by providing a proof of concept that a reproducible system for the production of UCX®-conditioned medium can be used to prime a secretome for eventual clinical applications.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-015-0082-5) contains supplementary material, which is available to authorized users.

Glu-Trp-ONa or its acylated analogue (R-Glu-Trp-ONa) administration enhances the wound healing in the model of chronic skin wounds in rabbits

The management of chronic skin wounds represents a major therapeutic challenge. The synthesized dipeptide (Glu-Trp-ONa) and its acylated analogue (R-Glu-Trp-ONa) were assessed in the model of nonhealing dermal wounds in rabbits in relation to their healing properties in wound closure. Following wound modeling, the rabbits received a course of intraperitoneal injections of Glu-Trp-ONa or R-Glu-Trp-ONa. Phosphate-buffered saline and Solcoseryl® were applied as negative and positive control agents, respectively. An injection of Glu-Trp-ONa and R-Glu-Trp-ONa decreased the period of wound healing in animals in comparison to the control and Solcoseryl-treated groups. Acylation of Glu-Trp-ONa proved to be beneficial as related to the healing properties of the dipeptide. Subsequent zymography analyses showed that the applied peptides decreased the proteolytic activity of matrix metalloproteinases MMP-9, MMP-8, and MMP-2 in the early inflammatory phase and reversely increased the activity of MMP-9, MMP-8, and MMP-1 in the remodeling phase. Histological analyses of the wound sections (hematoxylin-eosin, Mallory's staining) confirmed the enhanced formation of granulation tissue and re-epithelialization in the experimental groups. By administering the peptides, wound closures increased significantly through the modulation of the MMPs' activity, indicating their role in wound healing.

Matrix remodeling by MMPs during wound repair

Repair following injury involves a range of processes - such as re-epithelialization, scar formation, angiogenesis, inflammation, and more - that function, often together, to restore tissue architecture. MMPs carry out diverse roles in all of these activities. In this article, we discuss how specific MMPs act on ECM during two critical repair processes: re-epithelialization and resolution of scar tissue. For wound closure, we discuss how two MMPs - MMP1 in human epidermis and MMP7 in mucosal epithelia - facilitate re-epithelialization by cleaving different ECM or ECM-associated proteins to affect similar integrin:matrix adhesion. In scars and fibrotic tissues, we discuss that a variety of MMPs carry out a diverse range of activities that can either promote or limit ECM deposition. However, few of these MMP-driven activities have been demonstrated to be due a direct action on ECM.

Matrix metalloproteinases regulate extracellular levels of SDF-1/CXCL12, IL-6 and VEGF in hydrogen peroxide-stimulated human periodontal ligament fibroblasts

Periodontitis is a highly prevalent infectious disease characterized by the progressive inflammatory destruction of tooth-supporting structures, leading to tooth loss. The underling molecular mechanisms of the disease are incompletely understood, precluding the development of more efficient screening, diagnostic and therapeutic approaches. We investigated the interrelation of three known effector mechanisms of the cellular response to periodontal infection, namely reactive oxygen species (ROS), matrix metalloproteinases (MMPs) and cytokines in primary cell cultures of human periodontal ligament fibroblast (hPDLF). We demonstrated that ROS increase the activity/levels of gelatinolytic MMPs, and stimulate cytokine secretion in hPDLF. Additionally, we proved that MMPs possesses immune modulatory capacity, regulating the secreted levels of cytokines in ROS-stimulated hPDLF cultures. This evidence provides further insight in the molecular pathogenesis of periodontitis, contributing to the future development of more effective therapies.

HGF/Met-Signaling Contributes to Immune Regulation by Modulating Tolerogenic and Motogenic Properties of Dendritic Cells

Hepatocyte growth factor (HGF)-signaling via Met can induce mitogenic, morphogenic, and motogenic activity in various cell types. Met expression in the immune system is limited to cells with antigen-presenting capacities, including dendritic cells (DCs). Thus, it appears highly conceivable that Met-signaling impacts on adaptive immune responses. However, the mechanisms by which HGF imparts its effects on immunological responses are not yet fully understood. DCs possess unique functionalities that are critically involved in controlling both tolerance and immunity. HGF conveys immunoregulatory functions, which strongly correlate with that of DCs orchestrating the apt immune response in inflammation. Therefore, this review focuses on the current knowledge of Met-signaling in DCs with specific emphasis on the morphogenic and motogenic activities. HGF has been identified to play a role in peripheral immune tolerance by directing DC differentiation towards a tolerogenic phenotype. In skin immunity, Met-signaling was shown to drive mobilization of DCs by regulating matrix metalloproteinase activities. This is strikingly reminiscent of the role of Met for regulating a cell fate program during embryonic development, wound healing, and in tumor invasion known as epithelial-mesenchymal transition (EMT). Thus, the concept emerges that an EMT program is executed by Met-signaling in DCs, which will be also discussed.

IFI27, a novel epidermal growth factor-stabilized protein, is functionally involved in proliferation and cell cycling of human epidermal keratinocytes

OBJECTIVES

IFI27 is highly expressed in psoriatic lesions but its function has not been known. The present study aimed to explore its role in proliferation of epidermal keratinocytes.

MATERIALS AND METHODS

IFI27 knockdown and over-expression in keratinocytes were used to compare their proliferation, by MTT assay, apoptosis (by annexin V binding) and cell cycle progression by flow cytometry. Formation of cyclin A/CDK1 complex was examined by a co-immunoprecipitaion method. Anti-proliferation effects of IFI27 were also examined in vivo by topical application of IFI27 siRNA on imiquimod-induced psoriatic lesions, in a mouse model.

RESULTS

Epidermal growth factor was demonstrated to increase IFI27 expression by prolonging half-life of IFI27 protein. The IFI27 knockdown in keratinocytes reduced the proliferation rate, but had no effect on apoptosis nor on apoptosis-related genes. Interestingly, IFI27 knockdown resulted in S-phase arrest that was found to be associated with increased Tyr15 phosphorylation of CDK1, reduced CDC25B and reduced formation of cyclin A/CDK1 complex. In addition, IFI27 knockdown was also shown to activate p53 by Ser15 phosphorylation and increase p21 expression. Topical application of IFI27 siRNA on imiquimod-induced psoriatic lesion in a mouse model reduced epidermal thickness, formation of rete ridges and PCNA expression.

CONCLUSIONS

Our study demonstrates for the first time, that cell function of IFI27 is involved in proliferation of skin keratinocytes both in vitro and in vivo. It suggests that IFI27 might be a suitable target for development of a novel anti-psoriasis therapy.

Mechanisms behind signet ring cell carcinoma formation

Signet ring cell carcinomas are highly malignant dedifferentiated adenocarcinomas. There are no cell-cell interactions between these round-shaped cells. They contain huge numbers of vacuoles, filled with mucins, which are secreted from the cells. The mechanism behind this phenotype has recently begun to be elucidated. In highly differentiated adenocarcinomas the ErbB2/ErbB3 complex is activated, which is followed by phosphatidylinositol 3-kinase (PI3K) activation. p38 MAP kinase is activated downstream of PI3K and adherens junctions are disrupted via Rac1 activation. Loss of adherens junctions leads to the disappearance of tight junctions, which results in a loss of cell-cell interactions. Secretion of mucin is enhanced by activation of PI3K. One of the mucins - Muc4 - can activate ErbB2. Under normal conditions Muc4 and ErbB2 are separated by adherens and tight junctions, however in signet ring cells they are able to interact, since these junctions have been lost. Therefore, an activation loop is formed, consisting of ERbB2/ErbB3-Muc4-ErbB2/ErbB3. As a result, the ErbB2/ErbB3 signaling pathway becomes constitutively activated, cell-cell interactions are lost, and signet ring carcinomas are formed. As a result of constitutive activation of the ErbB2/ErbB3 complex, cell growth is continuously enhanced. Some signet ring cell carcinomas have been found to have mutations in the E-cadherin gene, which fits the above hypothesis.

Antiplatelet-derived growth factor (PDGF) activity in the saliva of ixodid ticks is linked with their long mouthparts

The saliva of blood-feeding arthropods modulates their vertebrate hosts' haemostatic, inflammatory and immune responses to facilitate blood feeding. In a previous study, we showed that salivary gland products from ixodid tick species also manipulate the wound-healing response by targeting at least four different mammalian growth factors: transforming growth factor β1, hepatocyte growth factor, fibroblast growth factor 2 and platelet-derived growth factor (PDGF). In addition, species that showed PDGF-binding activity also inhibited cell proliferation in vitro and induced changes in cell morphology accompanied by disruption of the actin cytoskeleton. Here, we show a correlation between the length of the tick hypostome, the sclerotized feeding tube of the mouthparts inserted into the host's skin and anti-PDGF activity. This apparent link between hypostome length, and hence the potential depth of skin damage, and PDGF-binding activity was not apparent for the other growth factors or for other cytokines important in wound healing (keratinocyte growth factor, interleukin 6 and stromal cell-derived factor 1). However, PDGF-binding activity was no longer correlated with anti-cell activities, indicating that an additional as yet unidentified activity in tick saliva may affect cellular changes in wound repair.

The effects of cytokines in adipose stem cell-conditioned medium on the migration and proliferation of skin fibroblasts in vitro

Although adipose stem cell-conditioned medium (ASC-CM) has demonstrated the effect of promoting the cutaneous wound healing, the mechanism for this response on the effector cells (e.g., dermal fibroblasts) during the process remains to be determined. In this study, we aim to investigate the types and contents of cytokines in ASC-CM and the effects of some kinds of common cytokines in ASC-CM, such as EGF, PDGF-AA, VEGF, and bFGF, on dermal fibroblasts proliferation and migration in wound healing process. Results showed that these four cytokines had high concentrations in ASC-CM. The migration of skin fibroblasts could be significantly stimulated by VEGF, bFGF, and PDGF-AA, and the proliferation could be significantly stimulated by bFGF and EGF in ASC-CM. Additionally, ASC-CM had more obvious promoting effect on fibroblasts proliferation and migration than single cytokine. These observations suggested that ASC-CM played an important role in the cutaneous injury partly by the synergistic actions of several cytokines in promoting dermal fibroblasts proliferation and migration, and ASC-CM was more adaptive than each single cytokine to be applied in promoting the wound healing.

Oncogenic K-Ras and loss of Smad4 mediate invasion by activating an EGFR/NF-κB Axis that induces expression of MMP9 and uPA in human pancreas progenitor cells

Activating K-Ras mutations and inactivating mutations of Smad4 are two common genetic alterations that occur in the development and progression of pancreatic ductal adenocarcinomas (PDAC). To further study the individual and combinatorial roles of these two mutations in the pathogenesis of PDAC, immortalized human pancreas nestin postive cells (HPNE) were genetically modified by either expressing oncogenic K-Ras (HPNE/K-Ras), by shRNA knock down of Smad4 (HPNE/ShSmad4) or by creating both alterations in the same cell line (HPNE/K-Ras/ShSmad4). We previously found that expression of oncogenic K-Ras caused an increase in expression of EGFR and loss of Smad4 further enhanced the up regulation in expression of EGFR and that this increase in EGFR was sufficient to induce invasion. Here we further investigated the mechanism that links mutational alterations and EGFR expression with invasion. The increase in EGFR signaling was associated with up regulation of MMP9 and uPA protein and activity. Moreover, the increase in EGFR signaling promoted a nuclear translocation and binding of RelA (p65), a subunit of NF-κB, to the promoters of both MMP-9 and uPA. Treatment of HPNE/K-Ras/ShSmad4 cells with an inhibitor of EGFR reduced EGF-mediated NF-κB nuclear translocation and inhibitors of either EGFR or NF-κB reduced the increase in MMP-9 or uPA expression. In conclusion, this study provides the mechanism of how a combination of oncogenic K-Ras and loss of Smad4 causes invasion and provides the basis for new strategies to inhibit metastases.

Senescent fibroblasts enhance early skin carcinogenic events via a paracrine MMP-PAR-1 axis

The incidence of carcinoma increases greatly with aging, but the cellular and molecular mechanisms underlying this correlation are only partly known. It is established that senescent fibroblasts promote the malignant progression of already-transformed cells through secretion of inflammatory mediators. We investigated here whether the senescent fibroblast secretome might have an impact on the very first stages of carcinogenesis. We chose the cultured normal primary human epidermal keratinocyte model, because after these cells reach the senescence plateau, cells with transformed and tumorigenic properties systematically and spontaneously emerge from the plateau. In the presence of medium conditioned by autologous senescent dermal fibroblasts, a higher frequency of post-senescence emergence was observed and the post-senescence emergent cells showed enhanced migratory properties and a more marked epithelial-mesenchymal transition. Using pharmacological inhibitors, siRNAs, and blocking antibodies, we demonstrated that the MMP-1 and MMP-2 matrix metalloproteinases, known to participate in late stages of cancer invasion and metastasis, are responsible for this enhancement of early migratory capacity. We present evidence that MMPs act by activating the protease-activated receptor 1 (PAR-1), whose expression is specifically increased in post-senescence emergent keratinocytes. The physiopathological relevance of these results was tested by analyzing MMP activity and PAR-1 expression in skin sections. Both were higher in skin sections from aged subjects than in ones from young subjects. Altogether, our results suggest that during aging, the dermal and epidermal skin compartments might be activated coordinately for initiation of skin carcinoma, via a paracrine axis in which MMPs secreted by senescent fibroblasts promote very early epithelial-mesenchymal transition of keratinocytes undergoing transformation and oversynthesizing the MMP-activatable receptor PAR-1.

Effects of 17β-estradiol on human corneal wound healing in vitro

PURPOSE

To investigate the effect of 17β-estradiol on corneal wound healing, particularly on epithelial mitosis and migration.

METHODS

Immortalized human corneal epithelial cells (HCECs) were cultured in media with different concentrations of 17β-estradiol (10, 50, 100, and 200 pg/mL), Dulbecco modified Eagle medium: Nutrient Mixture F-12 (negative control), and serum-containing Dulbecco modified Eagle medium: Nutrient Mixture F-12 (positive control). After 6 or 24 hours of hormone treatment, to evaluate the migratory potential of 17β-estradiol, wound healing assays were conducted via the manual scraping of HCECs and western blot analysis of fibronectin and matrix metalloproteinase 9 (MMP9). The proliferative potential of 17β-estradiol was evaluated via a proliferation assay using western blot analysis for proliferating cell nuclear antigen. In addition, epidermal growth factor (EGF) was measured by reverse transcription-polymerase chain reaction, and for the inhibition of epidermal growth factor receptor (EGFR)-mediated signal transduction, a wound healing assay was conducted after HCECs cultured with EGFR small interfering RNA were stimulated with 100 pg/mL 17β-estradiol.

RESULTS

Wound healing assay rates were enhanced as 17β-estradiol increased, with statistically significant changes seen in 50, 100, and 200 pg/mL 17β-estradiol-treated and positive control cells, compared with negative control cells (P < 0.05, in each group). Western blot analysis revealed that the expression of the MMP9 gene was upregulated by 17β-estradiol, and the expression of the fibronectin gene was downregulated by 17β-estradiol. The mitosis assay via western blot analysis showed that the expression cell cycle-associated protein, proliferating cell nuclear antigen, increased gradually as a result of 17β-estradiol treatment. Reverse transcription-polymerase chain reaction showed that EGF was upregulated by 17β-estradiol, and the EGFR small interfering RNA did not totally block the wound healing of the 17β-estradiol-treated cells but statistically significantly reduced the wound healing rate (P = 0.031).

CONCLUSIONS

17β-Estradiol facilitated the maintenance of the beneficial effect on corneal epithelial migration and proliferation, and the promoting effect of 17β-estradiol is partially related to increased EGF in vitro.

Galectin-3 regulates intracellular trafficking of EGFR through Alix and promotes keratinocyte migration

The EGFR-mediated signaling pathways are important in a variety of cellular processes, including cell migration and wound re-epithelialization. Intracellular trafficking of EGFR is critical for maintaining EGFR surface expression. Galectin-3, a member of an animal lectin family, has been implicated in a number of physiological and pathological processes. Through studies of galectin-3-deficient mice and cells isolated from these mice, we demonstrated that the absence of galectin-3 impairs keratinocyte migration and skin wound re-epithelialization. We have linked this pro-migratory function to a crucial role of cytosolic galectin-3 in controlling intracellular trafficking and cell surface expression of EGFR after EGF stimulation. Without galectin-3, the surface levels of EGFR are markedly reduced, and the receptor accumulates diffusely in the cytoplasm. This is associated with reduced rates of both endocytosis and recycling of the receptor. We have provided evidence that this previously unreported function of galectin-3 may be mediated through interaction with its binding partner Alix, which is a protein component of the ESCRT (endosomal sorting complex required for transport) machinery. Our results suggest that galectin-3 is potentially a critical regulator of a number of important cellular responses through its intracellular control of trafficking of cell surface receptors.

Epigenetic mechanisms in the pathogenesis of diabetic foot ulcers

The incidence of diabetes mellitus, a chronic metabolic disease associated with both predisposing genetic and environmental factors, is increasing globally. As a result, it is expected that there will also be an increasing incidence of diabetic complications which arise as a result of poor glycemic control. Complications include cardiovascular diseases, nephropathy, retinopathy and diabetic foot ulcers. The findings of several major clinical trials have identified that diabetic complications may arise even after many years of proper glycemic control. This has led to the concept of persistent epigenetic changes. Various epigenetic mechanisms have been identified as important contributors to the pathogenesis of diabetes and diabetic complications. The aim of this review is to provide an overview of the pathobiology of type 2 diabetes with an emphasis on complications, particularly diabetic foot ulcers. An overview of epigenetic mechanisms is provided and the focus is on the emerging evidence for aberrant epigenetic mechanisms in diabetic foot ulcers.

Matrix metalloproteinases (MMPs) are required for wound closure and healing during larval leg regeneration in the flour beetle, Tribolium castaneum

Regenerative abilities are found ubiquitously among many metazoan taxa. To compare mechanisms underlying the initial stages of limb regeneration between insects and vertebrates, the roles of matrix metalloproteinases (MMPs) and fibroblast growth factor (FGF) signaling were investigated in the red flour beetle, Tribolium castaneum. RNA interference-mediated knockdown of MMP2 expression delayed wound healing and subsequent leg regeneration. Additionally, pairwise knockdown of MMP1/2 and MMP2/3, but not MMP1/3, resulted in inhibition of wound closure. Wound healing on the dorsal epidermis after injury was also delayed when MMPs were silenced. Our findings show that functionally redundant MMPs play key roles during limb regeneration and wound healing in Tribolium. This MMP-mediated wound healing is necessary for the subsequent formation of a blastema. In contrast, silencing of FGF receptor did not interfere with the initial stages of leg regeneration despite the alterations in tanning of the cuticle. Thus, insects and vertebrates appear to employ similar developmental processes for the initial stages of wound closure during limb regeneration, while the role of FGF in limb regeneration appears to be unique to vertebrates.