Sclerotic atrophic plaques associated with a tattoo.

Lichen sclerosus is a chronic inflammatory disease, usually of the anogenital area, that causes intractable itching and soreness. Less commonly, it may have extragenital involvement in 15 to 20% of cases. Lichen sclerosus has been reported at sites of injury as a Koebner phenomenon. We report a case of lichen sclerosus at the site of a tattoo with simultaneous genital involvement.

Cutaneous pigmentation in health and disease: novel and well-established players.

Cutaneous pigment formation and aberration in disease are addressed. Dynoodt et al. (this issue) present data on a specific micro RNA that downregulates proteins involved in melanogenesis and melanosome movement. Kim et al. (this issue) present data showing that Wnt signaling is involved in the pathogenesis of melasma. Both articles enhance our understanding of cutaneous pigmentation and point to targets in the development of novel therapeutic modalities.

Melanocytes: a window into the nervous system.

Melanocytes are pigment-producing cells that originate from the dorsal portions of the closing neural tube in vertebrate embryos. Similar to neurons, they are derived from pluripotent neural crest cells that differentiate into numerous cell lineages. The development of melanocytes and neurons, as well as their differentiated function, within the mature tissue, is influenced by signaling molecules produced by neighboring cells. The same signaling molecules that have a role in the central and peripheral nervous tissue also have a role in cutaneous melanocytes. These include Wnt, bone morphogenetic proteins, endothelins, steel factor, hepatocyte growth factor, fibroblast growth factors, and neurotrophins. Signaling pathways including PKC- and p53/p73-dependent pathways are also common to melanocytes and neurons. The similarity between melanocytes and neurons suggests that melanocytes could provide a valuable model for studies of diseases that affect the nervous system, as well as for development of potential therapies for these diseases.

Inhibition of melanoma angiogenesis by telomere homolog oligonucleotides.

Telomere homolog oligonucleotides (T-oligos) activate an innate telomere-based program that leads to multiple anticancer effects. T-oligos act at telomeres to initiate signaling through the Werner protein and ATM kinase. We wanted to determine if T-oligos have antiangiogenic effects. We found that T-oligo-treated human melanoma (MM-AN) cells had decreased expression of vascular endothelial growth factor (VEGF), VEGF receptor 2, angiopoeitin-1 and -2 and decreased VEGF secretion. T-oligos activated the transcription factor E2F1 and inhibited the activity of the angiogenic transcription factor, HIF-1alpha. T-oligos inhibited EC tubulogenesis and total tumor microvascular density matrix invasion by MM-AN cells and ECs in vitro. In melanoma SCID xenografts, two systemic T-oligo injections decreased by 60% (P < .004) total tumor microvascular density and the functional vessels density by 80% (P < .002). These findings suggest that restriction of tumor angiogenesis is among the host's innate telomere-based anticancer responses and provide further evidence that T-oligos may offer a powerful new approach for melanoma treatment.

Telomeric DNA induces p53-dependent reactive oxygen species and protects against oxidative damage.

BACKGROUND: Reactive oxygen species (ROS) are generated by cellular metabolism as well as by exogenous agents. While ROS can promote cellular senescence, they can also act as signaling molecules for processes that do not lead to senescence. Telomere homolog oligonucleotides (T-oligos) induce adaptive DNA damage responses including increased DNA repair capacity and these effects are mediated, at least in part, through p53. OBJECTIVE: Studies were undertaken to determine whether such p53-mediated protective responses include enhanced antioxidant defenses. METHODS: Normal human fibroblasts as well as R2F fibroblasts expressing wild type or dominant negative p53 were treated with an 11-base T-oligo, a complementary control oligo or diluents alone and then examined by western blot analysis, immunofluorescence microscopy and various biochemical assays. RESULTS: We now report that T-oligo increases the level of the antioxidant enzymes superoxide dismutase 1 and 2 and protects cells from oxidative damage; and that telomere-based gammaH2AX (DNA damage) foci that form in response to T-oligos contain phosphorylated ATM and Chk2, proteins known to activate p53 and to mediate cell cycle arrest in response to oxidative stress. Further, T-oligo increases cellular ROS levels via a p53-dependent pathway, and these increases are abrogated by the NAD(P)H oxidase inhibitor diphenyliodonium chloride. CONCLUSION: These results suggest the existence of innate telomere-based protective responses that act to reduce oxidative damage to cells. T-oligo treatment induces the same responses and offers a new model for studying intracellular ROS signaling and the relationships between DNA damage, ROS, oxidative stress, and cellular defense mechanisms.

Telomere-mediated effects on melanogenesis and skin aging.

UV-induced melanogenesis (tanning) and "premature aging" or photoaging result in large part from DNA damage. This article reviews data tying both phenomena to telomere-based DNA damage signaling and develops a conceptual framework in which both responses may be understood as cancer-avoidance protective mechanisms.Journal of Investigative Dermatology Symposium Proceedings (2009) 14, 25-31; doi:10.1038/jidsymp.2009.9.

Role of BMP-4 and Its Signaling Pathways in Cultured Human Melanocytes.

Bone Morphogenetic Protein (BMP-4) was shown to down-regulate melanogenesis, in part, by decreasing the level of tyrosinase [Yaar et al. (2006) JBC:281]. Results presented here show that BMP-4 down-regulated the protein levels of TRP-1, PKC-beta, and MCI-R. When paired cultures of human melanocytes were treated with vehicle or BMP-4 (25 ng/ml), MAPK/ERK were phosphorylated within one hour of BMP-4 treatment. Then the activated MAPK/ERK caused an acute phosphorylation of MITF, followed by proteosome-mediated degradation of MITF, the key transcription factor for melanogenic proteins [Wu et al. (2000) Gene & Development:14]. However, prolonged exposure of melanocytes to BMP-4 (up to 48 hours) caused a decrease in the level of MITF-M transcript. In addition, BMP-4 decreased the intracellular level of cAMP, the key regulator of MITF expression. These results demonstrate that BMP-4 activates MAPK/ERK signaling pathway to transiently activate MITF; however, chronic treatment of BMP-4 to melanocytes causes a down-regulation of the expression of MITF, possibly in a cAMP-dependent pathway.

p75NTR antagonistic cyclic peptide decreases the size of beta amyloid-induced brain inflammation.

Amyloid beta (Abeta) was shown to bind the 75 kD neurotrophin receptor (p75(NTR)) to induce neuronal death. We synthesized a p75(NTR) antagonistic peptide (CATDIKGAEC) that contains the KGA motif that is present in the toxic part of Abeta and closely resembles the binding site of NGF for p75(NTR). In vivo injections of Abeta into the cerebral cortex of B57BL/6 mice together with the peptide produced significantly less inflammation than simultaneous injections of Abeta and a control (CKETIADGAC, scrambled) peptide injected into the contralateral cortex. These data suggest that blocking the binding of Abeta to p75(NTR) may reduce neuronal loss in Alzheimer's disease.

Lymphangiogenesis and angiogenesis in non-phymatous rosacea.

BACKGROUND: Our study evaluated the expression of vascular endothelial growth factor (VEGF), CD31 and D2-40 in involved and uninvolved skin of 18 patients with rosacea. METHODS: Immunostaining of facial skin specimens with VEGF, CD31 and D2-40 was compared between the lesional and the non-lesional skin of patients with erythemotelangiectatic and papulopustular rosacea. RESULTS: Significantly increased dermal expression of VEGF in lesional vs. non-lesional skin (88.9% and 55.6%) was observed. Dermal expression of CD31 and D2-40 was also increased in lesional vs. non-lesional skin. There was no statistically significant difference in cutaneous expression of VEGF, CD31 and D2-40 between patients with papulopustular and erythemotelangiectatic rosacea, and no correlation was found between disease duration and immunoreactivity of VEGF, CD31or D2-40. CONCLUSIONS: Our study showed marked immunostaining of lesional skin with VEGF, CD31 and D2-40 compared with non-lesional skin. Increased immunoreactivity of D2-40 in lesional skin is interesting, given that none of the patients had facial edema. There are no published data regarding the role of lymphangiogenesis in patients with non-phymatous rosacea; thus, our study represents a new understanding of its pathogenesis. Lack of correlation between D2-40 expression and disease duration suggests that lymphatics are involved early in the pathogenesis of rosacea and do not constitute a late event.

Cutaneous immunoreactivity of D2-40 antibody beyond the lymphatics.

Recent research suggests that the D2-40 monoclonal antibody recognizes the 40,000 Da O-linked sialoglycoprotein podoplanin. Podoplanin not only is highly expressed in lymphatic endothelium but also in other cell types, including sebaceous carcinoma cells. Using the D2-40 antibody, our purpose was to evaluate expression of podoplanin in sebaceous glands of normal skin. Twenty-four formalin-fixed, paraffin-embedded normal skin specimens (10 from scalp and 14 from cheeks) were immunostained using the D2-40 mouse monoclonal antibody. Strong immunostaining with D2-40 antibody was observed at the periphery of sebaceous glands and in skin lymphatic endothelium of all specimens, demonstrating that podoplanin is expressed in sebaceous glands of normal skin.

Telomeric DNA induces apoptosis and senescence of human breast carcinoma cells.

INTRODUCTION: Cancer is a leading cause of death in Americans. We have identified an inducible cancer avoidance mechanism in cells that reduces mutation rate, reduces and delays carcinogenesis after carcinogen exposure, and induces apoptosis and/or senescence of already transformed cells by simultaneously activating multiple overlapping and redundant DNA damage response pathways. METHODS: The human breast carcinoma cell line MCF-7, the adriamycin-resistant MCF-7 (Adr/MCF-7) cell line, as well as normal human mammary epithelial (NME) cells were treated with DNA oligonucleotides homologous to the telomere 3' overhang (T-oligos). SCID mice received intravenous injections of MCF-7 cells followed by intravenous administration of T-oligos. RESULTS: Acting through ataxia telangiectasia mutated (ATM) and its downstream effectors, T-oligos induced apoptosis and senescence of MCF-7 cells but not NME cells, in which these signaling pathways were induced to a far lesser extent. In MCF-7 cells, experimental telomere loop disruption caused identical responses, consistent with the hypothesis that T-oligos act by mimicking telomere overhang exposure. In vivo, T-oligos greatly prolonged survival of SCID mice following intravenous injection of human breast carcinoma cells. CONCLUSION: By inducing DNA damage-like responses in MCF-7 cells, T-oligos provide insight into innate cancer avoidance mechanisms and may offer a novel approach to treatment of breast cancer and other malignancies.

Features that determine telomere homolog oligonucleotide-induced therapeutic DNA damage-like responses in cancer cells.

Cancer is the second leading cause of death in the USA, with metastatic disease proving a particular management challenge. Treatment modalities for patients with metastatic disease are limited, and survival beyond 5 years is uncommon. We have reported that an 11-base DNA oligonucleotide 100% homologous to the telomere 3' overhang can induce apoptosis, senescence and/or differentiation of several types of malignant cells in vitro and in vivo, while having minimal effect on normal cells. We now report that 22 oligonucleotides, 9-20 bases in length, with or without a 5' phosphate group and with varying homology (40-100%) to the 3' overhang, inhibit growth and induce apoptosis of human cell lines derived from breast cancers, pancreatic and ovarian carcinomas, and malignant melanoma, lines that lack p53 and/or p16 and harbor a variety of other abnormalities in key regulatory signaling pathways. Cytosine (C) content adversely affected oligonucleotide efficacy, decreasing their effect on cellular apoptosis by > or =80%. These data confirm and expand our earlier work suggesting that such telomere homolog oligonucleotides (T-oligos) target an innate anti-cancer defense system in human cells and may provide an effective treatment for cancers of multiple different cellular origins and genetic profile.

Bone morphogenetic protein-4, a novel modulator of melanogenesis.

Bone morphogenetic proteins (BMPs), members of the transforming growth factor-beta family, signal in many cells including neural precursors. Two receptors, types 1 and 2, coordinately mediate BMP signaling, and type 1 receptor has two forms: A and B. Using RT-PCR we found that neural crest-derived human melanocytes express BMP receptor-1A, -1B, and -2. Furthermore, melanocytes and the surrounding keratinocytes express BMP-4, suggesting both autocrine and paracrine effects of this molecule. Moreover, BMP-4 supplementation of cultured human melanocytes decreases melanin synthesis, tyrosinase mRNA, and protein. The mechanism of this BMP-4 effect on tyrosinase and ultimately on melanogenesis involves modest decreases of tyrosinase transcription rate and mRNA stability. Moreover, ultraviolet irradiation, the best recognized environmental stimulator of melanogenesis, down-regulated the mRNA of BMP receptor-1B in melanocytes. Our data provide evidence of a novel regulatory pathway for melanogenesis in human skin.

Neurotrophins in skin biology and pathology.

Neurotrophins (NTs) belong to a family of growth factors, which control the development, maintenance, and apoptotic death of neurons and also fulfill multiple regulatory functions outside the nervous system. Biological effects induced by NTs strongly depend on the pattern of NT receptor/co-receptors expression in target cells, as well as on the set of intracellular adaptor molecules that link NT signalling to distinct biochemical pathways. In this review, we summarize data on the molecular mechanisms underlying the involvement of NTs in the control of non-neuronal functions in normal skin (e.g. keratinocyte proliferation, melanocyte development and apoptosis, hair growth). We also review the data on the role for NTs and their receptors in a number of pathological skin conditions (stress-induced hair loss, psoriasis, atopic dermatitis). Although additional efforts are required to fully understand mechanisms underlying the involvement of NTs and their receptors in controlling functions of normal and pathologically altered skin cells, substantial evidence suggests that modulation of NT signalling by NTs receptor agonists/antagonists may be developed as intervention modalities in distinct skin and hair growth pathologies.

Keratin 16 expression in epidermal melanocytes of normal human skin.

Although the prevailing dogma states that keratin filaments are the hallmark of keratinocytes and other epithelial cells, recent publications suggest that they may be expressed by a variety of normal and malignant cells of different embryonic origin. Keratin expression has been reported in fibroblasts and endothelial cells as well as in various sarcomas. Also, some human melanomas express keratins in addition to the traditional diagnostic markers of differentiation, such as S-100 and melanocyte-specific antigens. Many studies have shown that cultured cells obtained from various melanomas express keratin. Most recently, keratin expression has also been shown in cultured melanocytes of normal skin. We now report that normal human melanocytes in vivo express keratin 16 (K16) but not keratins 1, 5, 8, 10, 14, or even keratin 6, the type II partner that is normally expressed with K16 in keratinocytes. Similarly, melanocytes in vitro express K16 but not K6. Keratin 16 expression in vivo was present in basal melanocytes in specimens derived from donors (0-77 years) and from different anatomic locations, suggesting that keratin 16 is constitutively expressed by all melanocytes. It appears that keratin expression may be more prevalent than previously assumed, and that these cytoskeletal filaments may play important roles in tissues and cells other than epithelia.

Modulation of vascular endothelial growth factor receptors in melanocytes.

Vascular endothelial growth factor (VEGF) is constitutively produced by keratinocytes, but has no known epidermal target cell. We now report that normal human melanocytes (Mc) maintained in serum-free, hormone-, and growth factor-supplemented medium lacking phorbol ester and choleragen constitutively express VEGF receptor-1 (VEGFR-1), VEGFR-2, and neuropilin-1. Furthermore, stimulation of Mc with VEGF165 isoform leads to phosphorylation of VEGFR-2, the receptor responsible for most of the VEGF-mediated effects in endothelial cells, suggesting that the receptor is functional. Interestingly, in Mc, VEGFR-2 expression is induced by ultraviolet irradiation and is downregulated by VEGF and tumor necrosis factor-alpha. Prolonged culture (>8 weeks) in the presence of phorbol ester abrogates VEGFR-2 expression, explaining previous reports that Mc do not express VEGFR-1 and VEGFR-2. These data suggest that VEGF may play a role in Mc behavior in skin.

Solar-simulated irradiation evokes a persistent and biphasic IL-1alpha response.

Exposure of skin to solar-simulated irradiation generates a multitude of adaptive responses including cytokine transcription, synthesis and secretion. Interleukin-1 (IL-1) is one of the cytokines induced in epidermal cells in response to UV irradiation. It displays a broad range of mitogenic and inflammatory activities including fibroblast proliferation and T-cell activation. There are two forms, IL-1alpha and IL-1beta; and IL-1alpha is the predominant form secreted by epidermal keratinocytes. UV-induced modulations of IL-1alpha message levels have been extensively studied within the first 48 h after irradiation, but longer term changes and impact on IL-1alpha cellular protein levels are virtually unexplored. We now report that cells of keratinocyte origin (SCC 12F) respond to a single physiologic dose of solar-simulated irradiation with both early (8 h) and late (72 h) peaks of IL-1alpha mRNA induction. UV-stimulated IL-1alpha secretion is increased above sham-irradiated control secretion for at least 96 h after irradiation. Our study provides evidence that UV-induced adaptive cutaneous responses persist for at least several days, and suggests that different mechanisms may mediate the early vs. late inductions.

A trial of short incubation, broad-area photodynamic therapy for facial actinic keratoses and diffuse photodamage.

BACKGROUND: There is no completely satisfactory treatment for multiple actinic keratoses (AKs). OBJECTIVE: To evaluate the efficacy of short incubation, broad-area application of delta-aminolevulinic acid followed by exposure to activating light-photodynamic therapy (delta-ALA/PDT) for treatment of AKs and background photodamage. The benefit of pretreatment with 40% urea cream to enhance penetration and the use of topical 3% lidocaine hydrochloride to decrease discomfort were also evaluated. METHODS: Eighteen patients with at least 4 nonhypertrophic facial AKs and mild to moderate diffuse facial photodamage were enrolled in the study. For 7 days, 40% urea cream or vehicle was applied to half of the treatment area, and then delta-ALA was applied to the entire area for 1, 2, or 3 hours. Lidocaine hydrochloride (3%) or vehicle cream was also applied to the entire area 45 minutes before exposure to 10 J/cm(2) of blue light. Pain,phototoxic reactions, AK counts, and photodamage improvement were evaluated 1 day, 1 week, and 1 month after treatment in all patients and after 5 months in 10 patients. RESULTS: All patients experienced mild to moderate discomfort during treatment and moderate phototoxic effects for 1 week. At 1 and 5 months there was significant reduction in AKs in all groups and significant improvement of several photodamage parameters. Different delta-ALA application times and pretreatment with urea cream or lidocaine had no significant effect on the results. CONCLUSIONS: This delta-ALA/PDT protocol is safe and effective for AK treatment as well as for improving photodamage. Further studies with a larger cohort, longer follow-up, and histologic confirmation of the clinical data would be of value.