Epidermal Hyperplasia In Mice Research Articles

Kushenol C from Sophora flavescens protects against UVB-induced skin damage in mice through suppression of inflammation and oxidative stress

Sophora flavescens has been used in traditional medicine for the treatment of various diseases such as viral hepatitis, fever, cancer, and pain. It is known to contain many bioactive compounds including prenylated flavonoids such as kurarinone, sophoraflavanone G, kuraridine and isoxanthohumol. These flavonoids have been confirmed to have anti-inflammatory, α-glucosidase inhibitory and antioxidant performances. However, the protective activities against UV-induced skin damage of kushenol C from S. flavescens have not yet been elucidated. In this study, we explored the protective effect of kushenol C against the skin damage induced by UVB in mice. Our results showed that kushenol C treatment significantly recovered UVB-induced skin damage, the degradation of collagen, mast cell infiltration, together with epidermal hyperplasia in mice. Furthermore, the treatment of kushenol C remarkably suppressed the generation of pro-inflammatory mediators in the mice irradiated by UVB. More so, treatment with kushenol C suppressed the oxidative stress in mice irradiated by UVB. In conclusion, these results showed that kushenol C from S. flavescens has potentialities to treat skin injury via suppressing skin damage induced by UVB and oxidative stress.

Melatonin attenuates acute and chronic itch in mice: the antioxidant and anti-inflammatory effects of melatonin receptors.

BackgroundItch is a common symptom of skin diseases and significantly reduces patients’ quality of life. Melatonin has anti-inflammatory and antioxidant effects. Our study examined the potential anti-itch effects of melatonin (N-acetyl-5-methoxytryptamine) in mice.MethodsWe detected the effects of melatonin and its receptors on acute and chronic itch by conducting itching behavioral experiments in male C57 mice. Reactive oxygen species (ROS) levels and calcium ion (Ca2+) mobilization during acute itching production were explored using flow cytometry and calcium imaging techniques. Melatonin expression in the serum of the chronic itch model mice was determined by enzyme-linked immunoassays. Hematoxylin and eosin staining show the effects of melatonin on skin thickness in a chronic itch model. Cytokine and chemokine levels were determined by quantitative polymerase chain reaction.ResultsWe discovered that compound 48/80 (C48/80)- and chloroquine (CQ)-induced scratching were significantly decreased by intraperitoneal (i.p), intradermal, and intrathecal administration of melatonin in a dose-dependent manner in mice, and the co-administration of melatonin receptor antagonists abolished the anti-itch effects of i.d melatonin. The incubation of melatonin significantly decreased the intracellular ROS levels induced by C48/80 and CQ in cultured ND7/23 cells from a mouse x rat hybridoma nerve as neuron. Melatonin inhibited intracellular Ca2+ increases induced by CQ (but not C48/80) in cultured dorsal root ganglia (DRG) neurons. Melatonin (50 mg/kg i.p) attenuated imiquimod (IMQ)- or acetone and diethyl ether followed by acetone-ether-water (AEW)-induced chronic itch and epidermal hyperplasia in mice. Finally, melatonin treatment reduced the IMQ-induced expression of ST2 and interleukin-33 (IL-33) or the AEW-induced expression of interleukin 31 (IL-31) and interleukin 31 receptor A (IL-31 RA) in the mice.ConclusionsCollectively, our results indicate that melatonin attenuates acute and chronic itch, possibly via melatonin receptors, and its antioxidant, and anti-inflammatory effects in mice.

TRPA1 deficiency alleviates inflammation of atopic dermatitis by reducing macrophage infiltration

AimsThe aim of this study was to investigate the role of TRPA1 in the pathogenesis of AD. Main methodsThe experimental atopic dermatitis (AD)-like skin lesions were established using 2,4-dinitrochlorobenzene (DNCB). Mice were divided into three groups: TRPA1−/− and WT groups were treated with DNCB dissolved in a 3:1 mixture of acetone and olive oil; the negative control group was treated with 3:1 mixture of acetone and olive oil without DNCB. The treatment lasted for 21 days, after which the animals were sacrificed and their blood, ears and dorsal skin tissue samples were collected for analysis. Key findingsLower dermatitis score, ear thickness, pruritus score, and epidermal hyperplasia were observed in mice in TRPA1−/− mice compared to the WT group. Besides, lower dermal mast cell infiltration, proinflammatory cytokines, Th2 cytokines and the infiltration of macrophages were observed in the TRPA1−/− mice compared to the WT group. Furthermore, we demonstrated that TRPA1 antagonist HC-030031 could alleviate AD-like symptoms and reduce the degree of epidermal hyperplasia in mice. SignificanceTRPA1 has a crucial role during the AD pathogenesis in mice, thus may be used as a potential new target for treating patients with chronic skin inflammatory disease.

Fucoxanthin-Containing Cream Prevents Epidermal Hyperplasia and UVB-Induced Skin Erythema in Mice.

Microalgae represent a source of bio-active compounds such as carotenoids with potent anti-inflammatory and antioxidant properties. We aimed to investigate the effects of fucoxanthin (FX) in both in vitro and in vivo skin models. Firstly, its anti-inflammatory activity was evaluated in LPS-stimulated THP-1 macrophages and TNF-α-stimulated HaCaT keratinocytes, and its antioxidant activity in UVB-irradiated HaCaT cells. Next, in vitro and ex vivo permeation studies were developed to determine the most suitable formulation for in vivo FX topical application. Then, we evaluated the effects of a FX-containing cream on TPA-induced epidermal hyperplasia in mice, as well as on UVB-induced acute erythema in hairless mice. Our results confirmed the in vitro reduction of TNF-α, IL-6, ROS and LDH production. Since the permeation results showed that cream was the most favourable vehicle, FX-cream was elaborated. This formulation effectively ameliorated TPA-induced hyperplasia, by reducing skin edema, epidermal thickness, MPO activity and COX-2 expression. Moreover, FX-cream reduced UVB-induced erythema through down-regulation of COX-2 and iNOS as well as up-regulation of HO-1 protein via Nrf-2 pathway. In conclusion, FX, administered in a topical formulation, could be a novel natural adjuvant for preventing exacerbations associated with skin inflammatory pathologies as well as protecting skin against UV radiation.

Epigallocatechin-3-gallate attenuates acute and chronic psoriatic itch in mice: Involvement of antioxidant, anti-inflammatory effects and suppression of ERK and Akt signaling pathways

Chronic itch is a distressing symptom of many skin diseases and negatively impacts quality of life. However, there is no medication for most forms of chronic itch, although antihistamines are often used for anti-itch treatment. Epigallocatechin-3-gallate (EGCG), a major green tea polyphenol, exhibits anti-oxidative and anti-inflammatory properties. Our previous studies highlighted a key role of oxidative stress and proinflammatory cytokines in acute and chronic itch. Here, we evaluated the effects of green tea polyphenon 60 and EGCG on acute and chronic itch in mouse models and explored its potential mechanisms. The effects of EGCG were determined by behavioral tests in mouse models of acute and chronic itch, which were induced by compound 48/80, chloroquine (CQ), and 5% imiquimod cream treatment, respectively. We found that systemic or local administration of green tea polyphenon 60 or EGCG significantly alleviated compound 48/80- and chloroquine-induced acute itch in a dose-dependent manner in mice. Incubation of EGCG significantly decreased the accumulation of intracellular reactive oxygen species (ROS) directly induced by compound 48/80 and CQ in cultured ND7-23 cells, a dorsal root ganglia derived cell line. EGCG also attenuated imiquimod-induced chronic psoriatic itch behaviors and skin epidermal hyperplasia in mice. In addition, EGCG inhibited the expression of IL-23 mRNA in skin and TRPV1 mRNA in dorsal root ganglia (DRG). Finally, EGCG remarkably inhibited compound 48/80-induced phosphorylation of extracellular signal-regulated kinase (ERK) and imiquimod-induced p-AKT in the spinal cord of mice, respectively. Collectively, these results indicated EGCG could be a promising strategy for anti-itch therapy.

Topical Application of Glycolipids from Isochrysis galbana Prevents Epidermal Hyperplasia in Mice.

Chronic inflammatory skin diseases such as psoriasis have a significant impact on society. Currently, the major topical treatments have many side effects, making their continued use in patients difficult. Microalgae have emerged as a source of bio-active molecules such as glycolipids with potent anti-inflammatory properties. We aimed to investigate the effects of a glycolipid (MGMG-A) and a glycolipid fraction (MGDG) obtained from the microalga Isochrysis galbana on a TPA-induced epidermal hyperplasia murine model. In a first set of experiments, we examined the preventive effects of MGMG-A and MGDG dissolved in acetone on TPA-induced hyperplasia model in mice. In a second step, we performed an in vivo permeability study by using rhodamine-containing cream, ointment, or gel to determinate the formulation that preserves the skin architecture and reaches deeper. The selected formulation was assayed to ensure the stability and enhanced permeation properties of the samples in an ex vivo experiment. Finally, MGDG-containing cream was assessed in the hyperplasia murine model. The results showed that pre-treatment with acetone-dissolved glycolipids reduced skin edema, epidermal thickness, and pro-inflammatory cytokine production (TNF-α, IL-1β, IL-6, IL-17) in epidermal tissue. The in vivo and ex vivo permeation studies showed that the cream formulation had the best permeability profile. In the same way, MGDG-cream formulation showed better permeation than acetone-dissolved preparation. MGDG-cream application attenuated TPA-induced skin edema, improved histopathological features, and showed a reduction of the inflammatory cell infiltrate. In addition, this formulation inhibited epidermal expression of COX-2 in a similar way to dexamethasone. Our results suggest that an MGDG-containing cream could be an emerging therapeutic strategy for the treatment of inflammatory skin pathologies such as psoriasis.

Up-regulation of Interferon-inducible protein 16 contributes to psoriasis by modulating chemokine production in keratinocytes.

Psoriasis is a common chronic inflammatory skin disease characterized by epidermal hyperplasia and dermal inflammation. Keratinocyte activation is known to play a critical role in psoriasis, but the underlying mechanism remains unclear. Interferon-inducible protein 16 (IFI16), an innate immune system sensor, is reported to affect keratinocyte function. We therefore hypothesized that IFI16 promotes psoriasis by modulating keratinocyte activation. In the present study, we cinfirmed that IFI16 was overexpressed in epidermal keratinocytes of psoriasis patients. In addition, psoriasis-related cytokines, including IFN-γ, TNF-α, IL-17 and IL-22, induced IFI16 up-regulation in keratinocytes via activation of STAT3 signaling. We also observed that IFI16 activated the TBK1-NF-κB signaling, leading to the production of CXCL10 and CCL20. Importantly, knocking down p204, which is reported as the mouse orthologous of human IFI16, inhibited epidermal hyperplasia in mice with imiquimod-induced psoriasiform dermatitis. These findings indicate that IFI16 plays a critical role in the pathogenesis of psoriasis and may be a potential therapeutic target.

Reversal of Murine Epidermal Atrophy by Topical Modulation of Calcium Signaling

Cytosolic Ca(2+) signals are performed by Ca(2+) releases from the endoplasmic reticulum and Ca(2+) influx from the extracellular medium. Releases rely on the refilling of the intracellular Ca(2+) stores by the Ca(2+) influx "Store-Operated Calcium Entry" (SOCE) via the channel Orai1. Here we show that Orai1 expression, SOCE amplitude, and epidermal proliferation are decreased in the epidermis of patients with skin fragility when compared with aged nonatrophic skin. Epidermal atrophy was induced in mice by the inhibition of Orai1 with small interfering RNA and the topical application of a SOCE blocker BTP2. The inhibition of Orai1 impaired the heparin-binding epidermal growth factor (HB-EGF)-induced Ca(2+) influxes and fully prevented the mitogen effect of HB-EGF in primary human keratinocytes. Importantly, epidermal proliferation correlated with Orai1 expression in mice. Conversely, the topical application of an Orai1 activator, the benzohydroquinone (BHQ), increased the epidermal thickness and proliferation, whereas the pro-proliferative effect of BHQ was prevented by the inhibition of Orai1. Finally, the topical application of BHQ reversed the epidermal atrophy induced by corticosteroids in mice. The topical modulation of Ca(2+) signals may thus be a promising therapeutic strategy in dermatology.

A Toll-Like Receptor 7, 8, and 9 Antagonist Inhibits Th1 and Th17 Responses and Inflammasome Activation in a Model of IL-23-Induced Psoriasis

Psoriasis is a chronic inflammatory skin disease that involves the induction of T-helper 1 (Th1) and T-helper 17 (Th17) cell responses and the aberrant expression of proinflammatory cytokines, including IL-1β. Copious evidence suggests that abnormal activation of Toll-like receptors (TLRs) contributes to the initiation and maintenance of psoriasis. We have evaluated an antagonist of TLR7, 8, and 9 as a therapeutic agent in an IL-23-induced psoriasis model in mice. Psoriasis-like skin lesions were induced in C57BL/6 mice by intradermal injection of IL-23 in the ear or dorsum. IL-23-induced increase in ear thickness was inhibited in a dose-dependent manner by treatment with antagonist. Histological examination of ear and dorsal skin tissues demonstrated a reduction in epidermal hyperplasia in mice treated with the antagonist. Treatment with antagonist also reduced the induction of Th1 and Th17 cytokines in skin and/or serum, as well as dermal expression of inflammasome components, NLRP3 and AIM2, and antimicrobial peptides. These results indicate that targeting TLR7, 8, and 9 may provide a way to neutralize multiple inflammatory pathways that are involved in the development of psoriasis. The antagonist has the potential for the treatment of psoriasis and other autoimmune diseases.

Abstract LB-139: A novel mechanism of tumor suppression by Piasy through NF-kappaB/RelA DNA binding repression and cytoplasmic translocation

Abstract NF-kappaB activation is commonly associated with malignancy. Constitutive NF-kappaB activation contributes to tumor growth, metastasis, and resistance to chemotherapy and radiation therapy. Activators of NF-kappaB in human cancer include viral oncogenes, inflammatory cytokines, and the loss of tumor suppressors like CYLD. Loss of the protein inhibitor of signal transducer and activator of transcription family member Piasy is associated with malignant progression in chronic myelogenous leukemia and myelodysplastic syndrome, suggesting its role as a tumor suppressor. In this study, we provide evidence for a novel mechanism for NF-kappaB activation in human cancer through deficiency of Piasy. Piasy repressed NF-kappaB luciferase activity in response to TNFalpha, constitutively active IKK2, or overexpressed RelA. Piasy protein directly bound to RelA, through the C terminus of Piasy and the DNA binding domain of RelA, distinguishing it from other Pias family proteins that bind to RelA. Piasy inhibited DNA binding of RelA in cells, as detected by DNA affinity immunoblotting and chromatin immunoprecipitation. However, the DNA binding activity of purified RelA protein was not affected by purified Piasy protein, suggesting that Piasy indirectly represses RelA DNA binding in vivo. Analysis of cellular localization of Piasy and RelA proteins revealed that Piasy colocalized with RelA in the cytoplasm, correlated with enhanced RelA cytoplasmic translocation. In vivo consequences of Piasy depletion were shown in a mouse model of psoriasis-like epidermal hyperplasia in mice, and in human squamous cell carcinomas (SCC) of the skin. Piasy null mice topically treated with NF-kappaB activator imiquimod exhibited increased nuclear RelA in epidermis compared to wild type controls. Piasy levels in human skin SCC were inversely associated with nuclear RelA. These findings suggest a novel mechanism for Piasy as a tumor suppressor by the inhibition of NF-kappaB oncogenic pathways in human cancers. (This work was supported by NIH 5R01CA098577, and 5R01AR55651) Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-139. doi:10.1158/1538-7445.AM2011-LB-139

Wondonin, a novel compound, inhibits hypoxia-induced angiogenesis through hypoxia-inducible factor 1 alpha

Hypoxia regulates a variety of transcription factors including HIF-1, which has been considered a target for anti-angiogenic therapy. While searching for a novel anti-angiogenic agent that would inhibit HIF-1 activity, we identified wondonin, a new bis imidazole purified from an association of the sponges Poecillastra wondoensis. Wondonin significantly decreased hypoxia-induced HIF-1α protein and VEGF expression and inhibited angiogenesis in vitro and in vivo. Furthermore, wondonin down-regulated HIF-1α protein through the increased interaction with the pVHL in immortalized human keratinocyte cell line. Wondonin also decreased the immunoreactivities of CD31 and VEGF in epidermal hyperplasia in mice. Taken together, these results suggested that wondonin had the potential to become the anti-angiogenic therapeutic agent to target HIF-1α.

Histamine H1 and H2 Receptor Antagonists Accelerate Skin Barrier Repair and Prevent Epidermal Hyperplasia Induced by Barrier Disruption in a Dry Environment

Keratinocytes have histamine H1 and H2 receptors, but their functions are poorly understood. To clarify the role of histamine receptors in the epidermis, we examined the effects of histamine receptor antagonists and agonists applied epicutaneously on the recovery of skin barrier function disrupted by tape stripping in hairless mice. Histamine H2 receptor antagonists famotidine and cimetidine accelerated the recovery of skin barrier function, but histamine and histamine H2 receptor agonist dimaprit delayed the barrier repair. Application of compound 48/80, a histamine releaser, also delayed the recovery. Imidazole, an analog of histamine, had no effect. The histamine H1 receptor antagonists diphenhydramine and tripelennamine accelerated the recovery. Histamine H3 receptor agonist Nalpha-methylhistamine and antagonist thioperamide had no effect. In addition, topical application of famotidine or diphenhydramine prevented epidermal hyperplasia in mice with skin barrier disrupted by acetone treatment in a dry environment (humidity < 10%) for 4 d. In conclusion, both the histamine H1 and H2 receptors in the epidermis are involved in skin barrier function and the cutaneous condition of epidermal hyperplasia.

Appearance of Dark Keratinocytes Following Intracutaneous Injection of Cholera Toxin in Mouse Skin

Intracutaneous injection of cholera toxin (CT), exotoxin of Vibrio cholerae, induces epidermal hyperplasia in mice, rats, and hamsters. In the work reported here we found that, like other hyperplasiogenic compounds such as 12-O-tetradecanoylphorbol-13-acetate which are tumor promoters, CT induces dark basal keratinocytes (dark cells) in the epidermis of mice. These are distinct from other epidermal cells since they contain dense cytoplasm rich in ribosomes and tonofilaments. This was demonstrated by electron microscopy and by toluidine blue staining of paraffin- or Epon-embedded sections. They comprised 3.1% of interfollicular basal cells 24-64 h after injection of 1 ng CT as compared with 0.5% in saline-injected skin. It was found by autoradiography of paraffin sections that about 47.2% of dark cells were labeled with [3H]thymidine at these times, while under the same conditions, labeling indices of basal cells were about 30% at the peaks. These results are discussed in relation to tumor promotion in two-stage carcinogenesis of mouse skin.

Further evidence of the incompatible pharmacodynamic responses to colchicine of malignant and benign epidermal hyperplasia in mice of skin-tumor resistant strain.

Further evidence of the incompatible pharmacodynamic responses to colchicine of malignant and benign epidermal hyperplasia in mice of skin-tumor resistant strain.