Journal of Dermatological Science

Editorial Board

2010-08-01

Regulation of epidermal keratinocytes by growth factors

Yuji Shirakata — 2010-07-12

Abstract: Epidermal keratinocytes are the main component cells of the epidermis and their function is regulated by various kinds of growth factors, cytokines, and chemokines. Of these, members of the epidermal growth factor and fibroblast growth factor families, as wells as hepatocyte growth factor and insulin-like growth factor, play central roles in keratinocyte proliferation, while transforming growth factor-β, vitamin D3, and interferon-γ are important inhibitors of keratinocyte growth. Keratinocytes are known to produce many of the currently identified growth factors, cytokines and chemokines. Keratinocyte-derived growth factors and cytokines regulate immune and inflammatory responses, and play important roles in pathological skin conditions. This review focuses on the regulation of keratinocytes by growth factors, cytokines, and chemokines.

Chemokines and cutaneous lymphoma

Makoto Sugaya — 2010-07-12

Abstract: Chemokines are small molecules of 8–10kDa that induce chemotaxis and activation of certain subsets of leukocytes. It has been recently shown that chemokines have broader function such as inhibition of apoptosis of target cells. The expression patterns of chemokines and chemokine receptors are specific to certain organs and cells. Therefore, chemokines are important to elucidate the mechanism of organ-specific human diseases. Primary cutaneous lymphomas are characterized by proliferation of clonally expanded lymphocytes in skin, but without detectable systemic involvement at the first diagnosis. Many chemokines are reported to be expressed in lesional skin of cutaneous lymphoma. Moreover, tumor cells of a certain group of cutaneous lymphoma express limited numbers of chemokine receptors, suggesting that interactions between chemokines and their receptors may explain skin-tropism of these types of lymphoma. This article focuses on chemokines expressed in lesional skin of cutaneous lymphoma and discusses their possible roles in disease progression.

Erythropoietin promotes hair shaft growth in cultured human hair follicles and modulates hair growth in mice

2010-07-12

Abstract: Background: Recent studies have shown that erythropoietin (EPO)/erythropoietin receptor (EPOR) signaling exist in both human and mouse hair follicles (HFs).Objective: To investigate whether dermal papilla cells (DPCs) express functional EPOR and, if so, to investigate effects of EPO on hair shaft growth in cultured human scalp hair follicles and hair growth in mice.Methods: EPOR expression in DPCs and follicular keratinocytes was examined by RT-PCR and immunoblot. Phosphorylation of EPOR signaling pathway mediators by EPO treatment was examined by immunoblot. MTT assay was employed to check cell viability after EPO treatment. Hair shaft growth was measured in the absence or presence of EPO and matrix keratinocyte proliferation was examined by Ki-67 immunostaining in cultured hair follicles. Agarose beads containing EPO were implanted into dorsal skin of C57BL/6 mice to examine effects of EPO on hair growth in vivo.Results: EPOR mRNA and protein are expressed in cultured human DPCs. EPOR signaling pathway mediators such as EPOR and Akt are phosphorylated by EPO in DPCs. EPO significantly promoted the growth of DPCs and elongated hair shafts with increased proliferation of matrix keratinocytes in cultured human hair follicles. In addition, EPO not only promoted anagen induction from telogen but also prolonged anagen phase.Conclusions: EPO may modulate hair growth by stimulating DPCs that express functional EPOR.

Immuno-histochemical evaluation of solar lentigines: The association of KGF/KGFR and other factors with lesion development

2010-07-12

Abstract: Background: Solar lentigines (SLs) are macular hyperpigmented lesions associated with sun exposure and age. Histopathologically, SLs are defined by a hyperpigmented basal layer and elongated rete ridges. The molecular mechanisms involved in the formation and the development of SLs are not completely understood. Our earlier data show that keratinocyte growth factor (KGF) induces hyperpigmentary lesions with histological resemblance to SLs.Objective: To investigate the association of KGF/KGF receptor (KGFR) and other pigmentary genes with the progression of SL development. To better understand the possible role of KGF in the pathology of SLs.Methods: Archived human skin biopsies (24 SLs and 14 healthy skins) were studied using immunohistochemistry for KGF/KGFR, proliferation marker Ki67, stem cell marker keratin-15 (K15), tyrosinase (TYR), stem cell factor (SCF), and protease-activated receptor-2 (PAR-2).Results: An increase in TYR-positive cells and expression was found throughout SL progression, as compared to normal skin. The levels of KGF, KGFR, SCF, Ki67 and PAR-2 varied during SL progression. Ki67, K15 and KGF/KGFR were significantly upregulated at early-mid SL stages. The latest-stage SLs expressed the lowest levels of KGF, KGFR, SCF, Ki67 and PAR-2.Conclusions: The upregulation of KGF/KGFR might induce the formation of rete ridges and hyperpigmentation. The reduced levels of all examined proteins (except TYR and K15) suggest a possible inactive status (dormancy or quiescence) of advanced lesions.

Identification and analysis of an early diagnostic marker for malignant melanoma: ZAR1 intra-genic differential methylation

2010-07-12

Abstract: Background: Epigenetic changes such as aberrant DNA methylation and histone modification have been shown to play an important role in the tumorigenesis of malignant melanoma.Objective: To identify novel tumor-specific differentially methylated regions (DMRs) in human malignant melanoma.Methods: The aberrant methylation at 14 candidate human genomic regions identified through a mouse model study with quantitative DNA methylation analysis using the Sequenom MassARRAY system was performed.Results: The CpG island Exon 1 region of the Zygote arrest 1 (ZAR1) gene, which is responsible for oocyte-to-embryo transition, showed frequent aberrant methylation of 28 out of 30 (93%) melanoma surgical specimens, 16 of 17 (94%) melanoma cell lines, 0% of 4 normal human epidermal melanocyte (NHEM) cell lines, 0% of 10 melanocytic nevi and 100% of 51 various cancer cell lines. According to the real-time RT-PCR, the ZAR1 gene was overexpressed in part of the hypermethylated cell lines, while its low expression with bivalent histone methylation status was seen in unmethylated cell lines.Conclusion: Our findings suggest that the ZAR1 intra-genic differentially methylated region would be a useful tumor marker for malignant melanoma and may be other type of cancers. The involvement of ZAR1 in the carcinogenesis of melanoma, still remains unclear, although we have examined tumorigenic capacities by exogenous full-length ZAR1 over-expression and siRNA knock-down experiments.

Perturbation of lamellar granule secretion by sodium caprate implicates epidermal tight junctions in lamellar granule function

2010-08-01

Abstract: Background: Polarized secretion of lamellar granules (LGs) delivers various lipids, proteases, and protease inhibitors into the stratum corneum (SC) of the epithelium. Disruption of LGs is associated with severe cutaneous diseases, but the mechanism of their polarized secretion is not known. On the other hand, recent study shows epidermal tight junctions (TJs) localize in stratum granulosum (SG), and TJs are involved in polarized molecule secretion. Thus, we hypothesized epidermal TJs relate to polarized LGs secretion.Objective: To assess the possibility that epidermal TJs are involved in polarized LGs secretion.Methods: In order to examine LGs secretion, we used fluorescent ceramide (BODIPY® FL C5-ceramide) and a natural LG cargo, lympho-epithelial Kazal-type-related inhibitor (LEKTI), in cultured normal human epidermal keratinocytes and a reconstructed human epidermis. We investigated their alteration using the medium-chain fatty acid sodium caprate (C10), TJs inhibitor. In addition, LG distribution was observed by electron microscopy.Results: C10 significantly inhibited secretion of both fluorescent ceramide and LEKTI in cultured normal human epidermal keratinocytes and a reconstructed human epidermis. C10 also disturbed the polarized localization of fluorescent ceramide and LEKTI in the reconstructed epidermis. Electron microscopy revealed that a large number of LGs remained in corneocytes in the C10-treated epidermis, rather than being secreted.Conclusion: Our data indicate that C10 perturbs the polarized secretion of LGs. Our study therefore suggests that epidermal TJs are possibly involved in polarized LG secretion and provides new insights into potential of treatments for skin diseases caused by abnormal LG secretion.

Non-healing is associated with persistent stimulation of the innate immune response in chronic venous leg ulcers

2010-07-12

Abstract: Background: The molecular pathogenesis of chronic skin wounds is complex and not fully understood. Although these wounds are often characterized as being in a state of persistent inflammation, the impact and participation of the innate immune responses in sustaining this inflammation needs further investigation.Objective: We investigated the cytokine profiles, Toll-like receptor (TLR)-stimulating activities and the levels of the antibacterial peptide Lipocalin-2 (Lcn-2) in a series of healing and non-healing chronic venous leg ulcers (CVLUs) through a study time of 8 weeks.Methods: Wound fluids from healing and non-healing CVLUs were run on a Human Cytokine Antibody Array, and Lcn-2 levels measured with ELISA. HEK 293 cells transfected with TLR2 or TLR4 and their respective co-receptors, and human peripheral blood monocytes were then stimulated with the wound fluids from healing and non-healing venous leg ulcers.Results: Healing wounds were associated with decreasing levels of IL-1α, IL-1β and MIP-1δ, whereas in non-healing wounds decreasing levels of IL-8 and MIP-1α were found. Accordingly, wound fluid from non-healing CVLUs contained persistent Lcn-2 levels and TLR2- and TLR4-stimulating activities, while, in healing wounds, the TLR-stimulating activities decreased over time with significantly diminished levels of Lcn-2 (p<0.005).Conclusions: Innate immune responses contribute to the chronic inflammation in non-healing CVLUs through participation of Toll-like receptors. The levels of the antimicrobial peptide Lcn-2 in wound fluids from these ulcers are elevated as a reflection of this contribution.

Structural and functional differences in barrier properties of African American, Caucasian and East Asian skin

2010-08-01

Abstract: Background: Differences in structural and functional skin characteristics have been linked with ethnical background. But racial differences in skin have not been thoroughly investigated by objective methods and the data are often contradictory.Objectives: This study was undertaken to compare skin barrier-related parameters of the stratum corneum on African American, Caucasian and East Asian skin by objective measurements.Methods: Baseline values of trans epidermal water loss were collected on the face. Consecutive stratum corneum D-squame® tape strippings were collected on the panelist's ventral forearm and face to evaluate skin barrier strength and cohesion. Stratum corneum ceramides, maturation, measured as the transglutaminase-mediated cross-linking of stratum corneum proteins, and stratum corneum trypsin like enzyme activity were measured on the D-squame® tape strippings.Results: East Asian and to some extent Caucasian skin was characterized by low maturation and relatively weak skin barrier. African American skin was characterized by low ceramide levels and high protein cohesion in the uppermost layers of the stratum corneum. These data can be interpreted in terms of the high prevalence of xerosis in black skin and increased skin sensitivity in East Asian skin.Conclusion: These results demonstrate that skin properties at the level of the stratum corneum vary considerably among these ethnic groups. This contributes to an improved understanding of physiological differences between these study populations.

Granzyme B is a novel interleukin-18 converting enzyme

2010-07-12

Abstract: Background: Granzyme B (GrB) is recognized to induce apoptosis; however, little is known about its possible role in other biological events. IL-18, a potent inflammatory cytokine, is produced as an inactive precursor (proIL-18). Several cells, including monocytes/macrophage lineage and non-hematopoietic cells such as keratinocytes, produce proIL-18. ProIL-18 requires appropriate processing to become active. Caspase-1 is the authentic IL-18 processing enzyme and is essential for IL-18 release from monocyte/macrophage lineage cells. However, caspase-1 is absent in non-hematopoietic cells, suggesting that there is another candidate to cleave proIL-18 except for caspase-1.Objective: GrB can invade and be active in cytoplasm of non-hematopoietic cells via perforin, therefore we investigated whether GrB converts proIL-18 into the biologically active form.Methods: Recombinant proIL-18 (rproIL-18) was produced and purified for protease reaction with GrB; this incubate was evaluated by immunoblotting. Biological activity of the proteolytic fragment cleaved by GrB was determined by IFN-γ assay using KG-1 cells. IFN-γ induction was also analyzed between extracts from GrB(+)/caspase-1(−) human CD8+ T cells and proIL-18 from normal human keratinocytes (NHK).Results: The proteolytic fragment that GrB cleaved proIL-18 had the same sequence and biological activity compared with mature IL-18 cleaved by caspase-1. Culture extracts from CD8+ T cells was able to cleave proIL-18 into authentic mature IL-18. IFN-γ induction was also detected in NHK treated with CD8+ T cells.Conclusion: GrB is a potent IL-18 converting enzyme and suggest that GrB secreted by CTLs and/or NK cells may initiate IL-18 release from target cells, leading to the development of inflammation.

Analysis of the COL7A1 gene in Czech patients with dystrophic epidermolysis bullosa reveals novel and recurrent mutations

2010-07-12

Epidermolysis bullosa (EB) is a clinically and genetically heterogeneous group of heritable skin disorders. Fine et al. separated EB into 4 major types – epidermolysis bullosa simplex, junctional epidermolysis bullosa, dystrophic epidermolysis bullosa (DEB), and Kindler syndrome – on the basis of distinguishing ultrastructural sites of blister formation . Inheritance patterns of DEB may be autosomal dominant (DDEB) or autosomal recessive (RDEB). Both DDEB and RDEB result from mutations in the type VII collagen gene (COL7A1) . DDEB is usually associated with glycine substitutions within the collagenous domain of type VII collagen. In RDEB, the allelic variants include “silent” glycine substitutions (mutations manifested in a recessive state when inherited with another mutation), non-glycine missense variants, nonsense mutations, splice site mutations, deletions, and insertions .

Merkel cell polyomavirus in naevoid basal cell carcinoma syndrome-associated basal cell carcinomas and sporadic trichoblastomas

2010-08-01

Merkel cell carcinoma (MCC) is a very aggressive neuroendocrine non-melanoma skin cancer (NMSC) of elderly or immunosuppressed individuals . Approximately 80% of MCC harbor the recently detected Merkel cell polyomavirus (MCPyV) within the tumor DNA . MCPyV-positive MCC reveal tumor specific truncating mutations within the large T antigen (LTAg) of MCPyV which are not found in the MCPyV wildtype . Thus epidemiology, clonal integration and tumor specific mutations within the LTAg of MCPyV are strongly supporting an important role of MCPyV in the etiopathogenesis of human MCC. However, the presence of MCPyV has been reported in NMSC of immunosuppressed and immunocompetent patients, including squamous cell carcinomas (SCC), Bowen's disease (BD) and basal cell carcinoma (BCC) . BCCs are among the most common malignant skin tumors and show differentiation towards germinative cells of the hair follicle. In addition to sporadic forms, BCCs may occur in the context of the naevoid basal cell carcinoma syndrome (NBCCS) which is a rare disease with an autosomal dominant trait with high penetrance and variable phenotype. The underlying molecular causes of NBCCS are germline mutations of the tumor suppressor gene PTCH1 located on the long arm of chromosome 9q22.3 . It is of interest that sporadic trichoblastoma which is a relatively rare benign counterpart of BCC, also showing differentiation toward germinative cells of the hair follicle, has been linked to chromosome 9p22.3 .

Adiponectin and leptin modulate cell proliferation and cytokine secretion of normal human keratinocytes and T lymphocytes

Hidetoshi Takahashi, Masaru Honma, Akemi Ishida-Yamamoto, Hajime Iizuka — 2010-07-12

Adipocytokines, adiponectin and leptin, are involved in the development of metabolic syndrome . Recent evidence indicates the association of the metabolic syndrome with psoriasis, which is associated with increased serum leptin level and decreased serum adiponectin level . We examined the effect of adiponectin and leptin on keratinocytes and T lymphocytes.

Measuring mRNA level expression of tumor necrosis factor α and its receptors related genes in patients with systemic sclerosis

A. Lis-Święty, J. Gola, U. Mazurek, L. Brzezińska-Wcisło — 2010-07-12

Systemic sclerosis (SSc) is a connective tissue disease, in which skin, organs and systems, such as digestive tract, lungs, kidneys and heart are undergoing progressive fibrosis. Etiopathogenesis of this disease is still mostly unknown. Destruction and activation of endothelium and fibrosis process are related, among others, with expression of many cytokines. Tumor necrosis factor α (TNFα) may play a significant role at the early stage of SSc development, i.e. in vascular changes (Raynaud's phenomenon, RP) . However, influence of this factor on fibrosis is controversial. Actually there is good evidence that TNFα has anti-fibrotic effects at least in vitro . We have reported increased TNFαRI levels in sera of patients with SSc and some of the patients with RP evolving to SSc but TNFα protein levels were low or under limit of detection in SSc sera in our and some other studies .

Assessment of the skin irritation potential of quantum dot nanoparticles using a human skin equivalent model

2010-07-12

Due to a greater surface area per unit mass, nanoparticles (NPs) may have unique biologic properties . The skin is one of the main target tissues for exogenous toxic agents and therefore, the possibility of toxicity from NPs is an important issue in the advancement of nanotechnology. Quantum dot (QD) NPs are powerful, multipurpose interfaces for nanotechnology that overcome the limitations of previously used organic fluorophores and provide long-term and multicolor imaging of cellular and molecular interactions . Although QDs provide potentially invaluable benefits, such as biomedical imaging and drug delivery, they may also have potential for adverse effects on human health . Recent papers have demonstrated the cytotoxicity of QDs in cultured human keratinocytes, however, little is known about the skin irritation potential of QDs. Traditional monolayer cell cultures and human skin equivalent models (HSEMs) have been proposed for in vitro tests of cutaneous irritation. However, monolayer cultures result in direct exposure of test material to keratinocytes, which could result in an over-prediction of toxicity because of a lack of a barrier function . The HSEM consists of normal human epidermal keratinocytes that differentiate to form multi-layered cells . This model develops a stratum corneum (SC) with barrier functions, and is therefore useful for prediction of cutaneous irritation .

Microchimerism in psoriasis vulgaris: A preliminary report

Wanda Niepieklo, Wojciech Baran, Beata Nowakowska, Jacek C. Szepietowski — 2010-07-12

Psoriasis is a disease of multifactorial etiology including: genetic background, environmental factors and vascular and immune system disturbances. Current researches are dominated by the hypothesis that an immunological process with inflammatory reaction mediated through T lymphocytes plays a key role in the pathogenesis of this disease. Antigen presenting cells are crucial for T-cells regulation and are found in abundance in the epidermis and dermis of psoriatic lesions. The key element linking APC and T-cells is an antigen, however no definitive autoantigen or immunogen has been yet identified and hypothesis about psoriasis as autoimmune disease is still in debate .

Announcements

2010-08-01