Epidermal Samples Research Articles

Three Skin Sampling Methods for Molecular Characterisation of Free-Ranging Dugong (<I>Dugong dugon</I>) Populations

This study has demonstrated that it is possible to obtain large numbers of samples for genetic analysis from free-ranging dugongs using techniques that are rapid, inexpensive, and cause minimal disturbance to the animals. Of the three biopsy implements trialled here, the simple hand-scraper was superior in terms of success rate, short sampling time, ease of use, and minor effect on the behaviour of the dugong. Epidermal samples obtained through scraping of the dorsum yielded good quality nuclear DNA that was sufficient for genetic analysis. In summary, then, it is suggested that when genetic/molecular information is sufficient to answer a research question, biopsy sampling of dugongs may be preferable to capture. This method will be useful to researchers who wish to examine population structure through genetics; sample a large proportion of the population; or work in areas that are challenging because of their remote location, narrow seagrass banks, or murky waters.

In Vivo Identification of Solar Radiation-Responsive Gene Network: Role of the p38 Stress-Dependent Kinase

Solar radiation is one of the most common threats to the skin, with exposure eliciting a specific protective cellular response. To decrypt the underlying mechanism, we used whole genome microarrays (Agilent 44K) to study epidermis gene expression in vivo in skin exposed to simulated solar radiation (SSR). We procured epidermis samples from healthy Caucasian patients, with phototypes II or III, and used two different SSR doses (2 and 4 J/cm2), the lower of which corresponded to the minimal erythemal dose. Analyses were carried out five hours after irradiation to identify early gene expression events in the photoprotective response. About 1.5% of genes from the human genome showed significant changes in gene expression. The annotations of these affected genes were assessed. They indicated a strengthening of the inflammation process and up-regulation of the JAK-STAT pathway and other pathways. Parallel to the p53 pathway, the p38 stress-responsive pathway was affected, supporting and mediating p53 function. We used an ex vivo assay with a specific inhibitor of p38 (SB203580) to investigate genes the expression of which was associated with active p38 kinase. We identified new direct p38 target genes and further characterized the role of p38. Our findings provide further insight into the physiological response to UV, including cell-cell interactions and cross-talk effects.

Cultured human keratinocytes for optical transmission measurement

The challenges of measuring optical properties of human tissues include the thickness of the sample, homogenization, or crystallization from freezing of the tissue. This investigation demonstrates a method to avoid these problems by growing optically thin samples of human keratinocytes as a substitute for ex vivo epidermis samples. Several methods of growth were investigated. Resulting samples were measured on a spectrophotometer for transmission between 300 nm and 2600 nm. The efficacy of the cell growth was confirmed with histological examination of several cultured keratinocyte samples. Limitations were the requirement to measure samples immediately after removal from the incubation environment, and the absence of the irregular structures of normal skin such as hair and glands.

Large scale study of epidermal recovery after stratum corneum removal: dynamics of genomic response

The stratum corneum (SC) is a superficial skin compartment that protects the body from the outside environment. Any disturbance of this function induces cascading steps of molecular and cellular repair in the whole epidermis. The aim of this study was to investigate epidermal gene expression following SC removal by tape stripping. Twenty-nine healthy male volunteers were included (27 +/- 4 years old). Tape stripping was processed on one inner forearm, the other unstripped forearm served as a control. Epidermis samples were collected at 2, 6, 19, 30 and 72 h after tape stripping. Trans-epidermal water loss measurements were performed at each step to monitor barrier restoration. Total RNA was extracted from collected epidermis samples and analysed by using DermArray cDNA microarrays. Among 4000 genes under investigation, we found that the expression of 370 genes varied significantly at least once during the time following stripping. Using an original clustering method, the modulated genes were gathered into eight groups. A functional characterization of the clusters enabled us to get a dynamic and global view of the main molecular processes taking place during epidermal recovery.

Genomic instability in the epidermis induced by atomic bomb (A‐bomb) radiation

Radiation etiology is suggested in the occurrence of basal cell carcinoma (BCC) of the skin among atomic bomb (A-bomb) survivors. Any genotoxicity, including ionizing radiation, can induce a DNA damage response (DDR), leading to genomic instability (GIN), which allows the accumulation of mutations during tumorigenesis. In this study, the authors evaluated the presence of GIN in the epidermis of survivors as a late effect of A-bomb radiation. In total, 146 BCCs, including 23 cases arising from nonexposed skin, were identified in survivors from 1968 to 1999. The incidence rate (IR) of BCC was calculated with stratification by distance in kilometers from the hypocenter (< or =1.5 km, 1.6-2.9 km, and > or =3 km). Nineteen epidermal samples surrounding BCC at the nonexposed sites were collected and tested for p53 binding protein 1 (53BP1) expression with immunofluorescence. 53BP1 rapidly forms nuclear foci at the sites of DNA double strand breaks (DSBs). Because 1 manifestation of GIN is the induction of endogenous DSBs, the level of 53BP1-focus formation (DDR type) can be considered as a marker for GIN. : The incidence rate of BCC increased significantly as exposure distance approached the hypocenter. Of the 7 epidermal samples from the proximal group (< or =1.5 km), 5 samples predominantly expressed DDR and an abnormal type of 53BP1 expression. In contrast, 4 of 5 samples from the distal group (> or =3 km) and all samples from the control group predominantly expressed the stable type of 53BP1 expression in the epidermis. : The current results demonstrated the endogenous activation of DDR in the epidermis surrounding BCC in the proximal group, suggesting the presence of a GIN in the survivors as a late effect of A-bomb radiation, which may indicate a predisposition to cancer.

Enzyme-Independent NO Stores in Human Skin: Quantification and Influence of UV Radiation

Nitric oxide (NO) has many functions in the skin, including the mediation of inflammation and antimicrobial defense, wound healing, regulation of keratinocyte homeostasis, and regulation of apoptosis following UV radiation. NO is synthesized by a family of NO synthase enzymes, but its rapid release following UV exposure suggests the existence of preformed stores. NO can be converted into nitrite or nitrosothiols that are stable until cleaved by UV to release NO. Using dermal microdialysis, suction blister epidermal samples, and sweat collection, we demonstrated cutaneous concentrations of total NO-related products of 12+/-5.97 microM, 0.03+/-0.03 micromol mg(-1) epidermal protein, and 22+/-9.34 microM, respectively. The predominant oxyanion was nitrate (60-75%) followed by nitrite. S-Nitrosothiols were barely detectable. Serum total NO-related products correlated directly with those of the upper dermis and sweat (R(2)=0.62 and 0.3, respectively). UVA irradiation (10 mW cm(-2)) increased the yield of NO-related products by microdialysis, peaking after 30 minutes. Dialysis with noradrenaline abrogated this rise. Both the skin and the dermal vasculature contain biologically significant stores of NO, particularly nitrite, which can be directly mobilized by UVA irradiation. The level of circulating NO-related products probably determines skin-bound stores.

Development of a minimally invasive epidermal abrasion device for clinical skin sampling and its applications in molecular biology

A new abrasion tool (US patent US7087063 B2) has been developed for collecting skin epidermal samples. This device includes a central shaft that holds the probe in a split chuck. Of the variety of probe designs tested, the laser-cut hollow tube (HT) probe abraded the basal layer of the epidermis most consistently, resulting in representative epidermal skin samples. Compared with traditional clinical methods, the abrasion method allows for high-throughput epidermal skin collection with minimal invasiveness to the volunteer subjects. A large number of abrasion samples have been collected in various clinical studies with no adverse effects observed. Epidermal abrasion, when used appropriately and with the optimized probes, can yield high quality tissue samples that are representative of the epidermis. A sufficient quantity of RNA and protein can be obtained for many subsequent molecular and biochemical applications. Because of its minimal invasiveness and high-throughput nature, the abrasion method can be a valuable tool used to investigate the efficacy of topical applications of skin care products.

Forskolin Protects Keratinocytes from UVB-Induced Apoptosis and Increases DNA Repair Independent of its Effects on Melanogenesis

Melanin pigments provide efficient protection against ultraviolet B (UVB) radiation but DNA repair also plays a key role in eliminating UV-induced damage and preventing the development of skin cancers. In this study, we demonstrate that forskolin (FSK), an agent that increases intracellular levels of cAMP, protects keratinocytes from UVB-induced apoptosis independently from the amount of melanin in the skin. FSK enhances the removal of the two major types of UVB-induced DNA damage, cyclobutane pyrimidine dimers and 6,4-photoproducts, by facilitating DNA repair. These findings suggest new preventive approaches with topical formulations of FSK or other bioactive agents that could be applied to the skin before sun exposure to increase its ability to repair DNA damage.

Nuclear staining and relative distance for quantifying epidermal differentiation in biomarker expression profiling

BackgroundThe epidermal physiology results from a complex regulated homeostasis of keratinocyte proliferation, differentiation and death and is tightly regulated by a specific protein expression during cellular maturation. Cellular in silico models are considered a promising and inevitable tool for the understanding of this complex system. Hence, we need to incorporate the information of the differentiation dependent protein expression in cell based systems biological models of tissue homeostasis. Such methods require measuring tissue differentiation quantitatively while correlating it with biomarker expression intensities.ResultsDifferentiation of a keratinocyte is characterized by its continuously changing morphology concomitant with its movement from the basal layer to the surface, leading to a decreased average nuclei density throughout the tissue. Based thereon, we designed and evaluated three different mathematical measures (nuclei based, distance based, and joint approach) for quantifying differentiation in epidermal keratinocytes. We integrated them with an immunofluorescent staining and image analysis method for tissue sections, automatically quantifying epidermal differentiation and measuring the corresponding expression of biomarkers. When studying five well-known differentiation related biomarkers in an epidermal neck sample only the resulting biomarker profiles incorporating the relative distance information of cells to the tissue borders (distance based and joint approach) provided a high-resolution view on the whole process of keratinocyte differentiation. By contrast, the inverse nuclei density approach led to an increased resolution at early but heavily decreased resolution at late differentiation. This effect results from the heavy non-linear decay of DAPI intensity per area, probably caused by cytoplasmic growth and chromatin decondensation. In the joint approach this effect could be compensated again by incorporating distance information.ConclusionWe suppose that key mechanisms regulating tissue homeostasis probably depend more on distance information rather than on nuclei reorganization. Concluding, the distance approach appears well suited for comprehensively observing keratinocyte differentiation.

Diffusion measurements in epidermal tissues with fluorescent recovery after photobleaching

Pressure ulcers are areas of soft tissue breakdown, resulting from sustained mechanical loading of the skin and underlying tissues. Measuring biochemical markers that are released upon mechanical loading by the epidermis seems a promising method for objective risk assessment of the development of pressure ulcers. This risk assessment method will better determine the risk of a patient to develop pressure ulcers than the risk score lists currently used. So far, experimental studies have been performed that measure the tissue response in the culture supernatant. To elucidate the transport of the biochemical markers within the epidermis, the diffusion coefficient needs to be established. In the current study, fluorescent recovery after photobleaching (FRAP) is used to determine the diffusion coefficient of fluorescent-labeled dextran molecules in human epidermis, porcine epidermis and engineered epidermal equivalents. These dextran molecules have a similar weight to the biochemical markers. Similar diffusion coefficients were found for human and porcine epidermal samples (6.2 x 10(-5)+/-1.2 x 10(-5) and 5.9 x 10(-5)+/-6.1 x 10(-6) mm2/s, respectively), whereas the diffusion coefficient of the engineered epidermal equivalent was significantly lower (2.3 x 10(-5)+/-1.0 x 10(-5) mm2/s). The diffusion could be measured in epidermal tissues using FRAP. In the future, the diffusion coefficients obtained in the current study will be used to study the difference between the transport in EpiDerm cultures and in human epidermis.

Exposure to heptachlor: Evaluation of the effects on the larval and adult epidermis of Rana kl. esculenta

Widely used in the past against termites and soil insects, the chlorinated insecticide heptachlor (H) is a toxic contaminant which represents a risk for both terrestrial and aquatic organisms. Like many organochlorine pesticides, heptachlor and heptachlor epoxide (HE), with oxidation products synthesized by many plant and animal species, degrade slowly since many of the derived compounds are persistent. This increases the status of heptachlor as a hazardous pollutant. In the present experimental study we exposed specimens of Rana kl. esculenta, from the tadpole stage through to their complete metamorphosis, to three different concentrations of heptachlor (4, 40 and 400 ppb). Mortality and HE bioaccumulation were evaluated on all the experimental groups. Since amphibian integument directly interacts with the environmental constituents (water, air and soil), we investigated the toxic effects on the ventral epidermis of both tadpole and adult samples by employing such histo-cytopathological biomarkers as ultrastructural morphology, certain enzyme activities (acid and alkaline phosphatases, AcPase, and AlkPase; succinic dehydrogenase, SDH; α-naphtyl butyrate esterase, ANBE; nitric oxide synthase/NADPH diaphorase, NOS/NADPHd). Also, the levels of reactive oxygen species (ROS) in the different conditions were evaluated. The results obtained were of ecological relevance, in particular as regards the effects of this environmental toxicant on the samples of tadpole epidermis. Severe morphological alterations were observed in the larval epidermal cells (apical and skein cells), whereas the cell epidermis (keratinocytes and mitochondria-rich cells) of the adult survivors showed changes in enzyme activities, particularly those involved in the protective response to xenobiotic injury. In general, morpho-histochemical studies, analysis of HE bioaccumulation and mortality showed a relation to the H doses employed.

Comparison of antimicrobial activity in the epidermal mucus extracts of fish

The mucus layer on the surface of fish consists of several antimicrobial agents that provide a first line of defense against invading pathogens. To date, little is known about the antimicrobial properties of the mucus of Arctic char ( Salvelinus alpinus), brook trout ( S. fontinalis), koi carp ( Cyprinus carpio sub sp. koi), striped bass ( Morone saxatilis), haddock ( Melanogrammus aeglefinus) and hagfish ( Myxine glutinosa). The epidermal mucus samples from these fish were extracted with acidic, organic and aqueous solvents to identify potential antimicrobial agents including basic peptides, secondary metabolites, aqueous and acid soluble compounds. Initial screening of the mucus extracts against a susceptible strain of Salmonella enterica C610, showed a significant variation in antimicrobial activity among the fish species examined. The acidic mucus extracts of brook trout, haddock and hagfish exhibited bactericidal activity. The organic mucus extracts of brook trout, striped bass and koi carp showed bacteriostatic activity. There was no detectable activity in the aqueous mucus extracts. Further investigations of the activity of the acidic mucus extracts of brook trout, haddock and hagfish showed that these fish species had specific activity for fish and human pathogens, demonstrating the role of fish mucus in antimicrobial protection. In comparison to brook trout and haddock, the minimum bactericidal concentrations of hagfish acidic mucus extracts were found to be ∼ 1.5 to 3.0 times lower against fish pathogens and ∼ 1.6 to 6.6 folds lower for human pathogens. This preliminary information suggests that the mucus from these fish species may be a source of novel antimicrobial agents for fish and human health related applications.

Evidence that dysregulated DNA mismatch repair characterizes human nonmelanoma skin cancer

In addition to an established role in the repair of postreplicative DNA errors, DNA mismatch repair (MMR) proteins also contribute to cellular responses to exogenous DNA damage. Previously, we have shown that Msh2-null mice display increased sensitivity to ultraviolet (UV) B-induced tumorigenesis, but squamous cell carcinomas (SCC) generated are microsatellite stable, suggesting a role for MMR other than postreplicative repair in UV-induced cutaneous tumour formation. We questioned whether there was evidence of MMR dysfunction in human SCC, thus validating the mouse models of MMR-dependent UVB-induced skin cancer. Using tissue microarrays we examined both nuclear and cytoplasmic levels of MMR proteins MSH2, MSH6, MSH3, MLH1 and PMS2 in more than 200 cases of cutaneous SCC and basal cell carcinoma (BCC). We found that subsets of these 10 MMR protein measures were increased in nonmelanoma skin cancer (NMSC) compared with normal epidermal samples; this was particularly true of SCC. In fact, based on post hoc tests and MMR protein distribution patterns, BCC was distinct from SCC. With the exception of nuclear MSH2, the BCC had lower levels of identified MMR protein measures than SCC. We believe this to be important because not only is SCC more aggressive than BCC, but evidence suggests that these two NMSC subtypes arise through different molecular pathways. In combination with previously established roles for MMR proteins in response to UVB-induced DNA damage, our data point towards an expanded perspective of the importance of MMR proteins in the suppression of UVB-induced tumorigenesis and, potentially, tumour behaviour.

Immunohistochemical comparison of β‐catenin expression by human normal epidermis and epidermal tumors

beta-Catenin, a cytoplasmic protein that binds directly to the intracellular domain of cadherin, controls various functions such as cell adhesion. In many human carcinomas, E-cadherin-mediated cell-cell adhesion is lost or disturbed and related to metastasis. The purpose of this study was to compare the expression of beta-catenin in the normal epidermal keratinocytes and samples from cutaneous benign and malignant epidermal tumors in 140 patients. Our study population consisted of 140 patients with benign or malignant epidermal tumors. Using immunohistochemical methods, we compared the expression of beta-catenin in their normal epidermal keratinocytes, and in samples from 61 benign (seborrheic keratosis, n = 33; verruca vulgaris, n = 14; keratoacanthoma, n = 14), and 79 malignant (Bowen's disease, n = 18; basal cell carcinoma, n = 33; squamous cell carcinoma, n = 28) epidermal tumors. beta-Catenin was found to be expressed in the cell membrane of normal keratinocytes. Compared to other cell components of the normal epidermis, basal cells showed the strongest beta-catenin expression in all 140 patients. While absent in three of 61 benign tumors, compared to normal basal cells, the expression of beta-catenin in the other 58 tumors was not significantly different; it was reduced in 71 of 79 malignant tumors (P < 0.0001). In Bowen's disease, the expression of beta-catenin on the tumor cell membrane was reduced, however, strong expression was seen in the nuclei and cytoplasm. Our results suggest that beta-catenin expression on the membrane of keratinocytes is associated with the differentiation of normal keratinocytes but not with their stage of differentiation, nor with the proliferation ability of epidermal tumor cells.

Freeze-Crack Technique to Study Epidermal Development in Zebrafish Using Differential Interference Contrast Microscopy and Fluorescent Markers

The zebrafish is a model organism used to study organogenesis during vertebrate development; however epidermis development has been the focus of only a few studies. Thus, new methodologies to highlight and study epidermal cells could be valuable to deepen our understanding of skin development. Large-scale mutagenic screenings have already identified many zebrafish mutants, which are models for human developmental diseases, however only four epidermis mutants have been isolated. Novel screening techniques are needed to improve this collection. We designed and tested a novel freeze-crack technique to obtain, fix, and stain epidermal cells from 5 days postfertilization zebrafish larvae. Using commercially available fluorescent markers and differential interference contrast (DIC) microscopy, we were able to label and highlight subcellular structures such as microridges, cell boundaries, nuclei, and the Golgi complex from epidermis cells. Acquiring and processing epidermis samples from 15 to 75 larvae takes about 2-4 h, respectively. Therefore this method could be used as part of large-scale screenings. In addition, we present a more extensive protocol for antibody staining, which could be employed for more specific studies.

X-ray diffraction patterns and anatomical properties of claw tissues of beef and dairy cattle

SUMMARYMedial claws from the right hind feet were obtained post mortem from four 19–20-month-old beef heifers and from four 28-month-old first-calving dairy heifers 3–4 days postpartum. X-ray diffraction (XRD) studies were undertaken on samples of soft and hard (cornified) integumental tissues of dorsal wall, sole and heel (bulb) for varying sites and planes of exposure. The measurements were interpreted as defining diffraction patterns and intermolecular spacings of cytoskeletal and extracellular fibrous structural proteins. The orientation of these proteins was examined in relation to physical characteristics and function including bearing of body weight by these tissues.Physical measurements taken included impression hardness which showed typically greater values for wall than sole and variable differences between horn of dairy and beef origin and husbandry systems. Claws from dairy heifers had significantly smaller values for toe (dorsal wall) angle, claw height and heel height and thickness of solear horn and heel soft tissue. Although few were studied, the results reflected typical husbandry origins and indicated the susceptibility to the lesion formation well recognized in postpartum dairy cattle.Typical XRD patterns for horn samples showed defined arcs of reflectance on the equatorial axis consistent with findings for the presence of α-helices in fibrils reported to occur in other hard-keratin-containing integumental tissues. However, reflectance on the meridional axis also reported for these other tissues was not detected. A similar defined pattern was obtained for less than 0·10 of samples of internal soft pre-cornified epidermal and attached dermal tissue although the values for intermolecular ‘d’ spacing for these were consistent with those reported for type I collagen. Diffuse reflection patterns were thus evident for the majority of samples of soft tissue epidermis and dermis and also for adipose tissue of the digital cushion.The formation of defined arcs of reflectance allowed the determination of fibril alignment in wall and solear horn. For the orientated samples of dorsal wall horn tissue, the outer layer showed a longitudinal angle of orientation essentially maintained proximal to distal. This pattern was maintained throughout the depth of horn at the proximal site. In contrast, layers in mid-wall and towards the distal edge showed a greater circumferential (horizontal) orientation in sections collected anterior to posterior towards the inner corial, including laminar, tissues. The orientation of fibrils in inner wall horn appears to relate to the direction of load-bearing forces in connecting horn to the distal phalanx. Horizontal alignment of fibrils was observed in the sole. In presenting the long axis of cells to the ground surface this orientation may facilitate erosive forces and contribute to the thinning of cornified sole horn under adverse underfoot conditions.

A comparative study on innate immune parameters in the epidermal mucus of various fish species

Fish epidermal mucus and its components provide the first line of defense against pathogens. Little is known about the role of epidermal mucus enzymes in the innate immune system of fish species such as Arctic char ( Salvelinus alpinus), brook trout ( S. fontinalis), koi carp( Cyprinus carpio), striped bass ( Morone saxatilis), haddock, ( Melanogrammus aeglefinus), Atlantic cod ( Gadus morhua) and hagfish ( Myxine glutinosa). The epidermal mucus samples from these fish were analysed for the specific activities of various hydrolytic enzymes including lysozyme, alkaline phosphatase, cathepsin B and proteases and the enzyme levels were compared among the fish species. Of all the species hagfish mucus showed a high activity for lysozyme and proteases and koi carp mucus had the highest levels of alkaline phosphatase and cathepsin B. A wide variation in enzyme activities was observed among the seven species and also between species of same family such as Arctic char and brook trout (salmonidae), haddock and cod (gadidae). Only lysozyme levels showed a marked variation with salinity where seawater fish showed approximately two times higher lysozyme activity than freshwater-reared fish species. Characterization of proteases with specific inhibitors showed Arctic char, brook trout, haddock and cod having higher levels of serine over metalloproteases whereas koi carp and striped bass had higher levels of metalloproteases over serine proteases. In contrast, hagfish had almost equal proportion of both serine and metalloproteases. This study demonstrates variation in the level of hydrolytic enzymes in the epidermal mucus of fish. These results provide preliminary information for a better understanding of the role of epidermal mucus and its components in the fish innate immune system.

Systematic significance of leaf epidermal features in Apios and Cochlianthus (Leguminosae)

Nineteen leaf epidermis samples representing six species in Apios and two in Cochlianthus were examined for the first time using both light microscopy and scanning electron microscopy. Leaf epidermal characters of these two closely related genera, such as shape of cells, pattern of anticlinal walls, cuticular membrane and wax ornamentation, are usually stable within species and thus of great significance in understanding the relationships between and within genera. The results indicate that (1) A. gracillima Dunn should be recognized as a distinct species, not a variety of Apios delavayi Franch., (2) the division of Apios into two subgenera is unreasonable, and (3) Apios and Cochlianthus are retained as two distinct genera. Key word Leguminosae, Apios, Cochlianthus, leaf epidermis, systematics.

Tight junction components occludin, ZO-1, and claudin-1, -4 and -5 in active and healing psoriasis

Cells of the granular layer are interconnected by tight junctions (TJs) in normal epidermis. The structural proteins of epidermal TJs include occludin, ZO-1, and claudin-1 and -4. Our aim was to correlate the expression of TJ components with keratinocyte differentiation using psoriasis as a model of premature keratinization. The distribution of TJ proteins was evaluated in the skin of nine patients with psoriasis. Punch biopsies were taken from perilesional skin, from active psoriasis plaques, and from healed, previously lesional locations. The punch biopsies were analysed using indirect immunolabelling for ZO-1, occludin and claudin-1, -4 and -5. In addition, epidermal samples were analysed by reverse transcription-polymerase chain reaction for claudin-1, -4 and -5 mRNAs. Claudin-5 was localized to the granular cell layers of normal control skin as well as perilesional and lesional psoriatic epidermis. This was unexpected, as previous studies have not detected claudin-5 in the epidermis. Occludin and ZO-1 were expressed in the granular cell layer in psoriatic perilesional epidermis. In the psoriasis plaques, ZO-1 and occludin were detected in a wider zone extending from the granular layer to the middle spinous cell layers. In healed psoriasis plaques, the expression of occludin and ZO-1 resumed a normal-looking profile, being restricted to the upper epidermis only. Claudin-1 and -4 did not show marked changes in psoriasis compared with normal skin. The results demonstrate claudin-5 in normal epidermis and psoriatic skin, and abnormal distribution of occludin and ZO-1 in psoriasis plaques. Clinical healing of aberrant keratinization is associated with restoration of the normal distribution of occludin, ZO-1 and also involucrin.

Genomic-scale analysis of psoriatic skin reveals differentially expressed insulin-like growth factor-binding protein-7 after phototherapy

Phototherapy is an effective therapy for psoriasis. The molecular mechanisms underlying its efficacy are not yet understood. To compare the expression profiles of psoriatic epidermis in patients before and after undergoing phototherapy with the purpose of expounding the molecular mechanisms underlying the efficacy of this therapeutic modality. Patients with psoriasis were investigated before and after full courses of phototherapy: three patients completed 3 weeks of heliotherapy at the Dead Sea; three patients received narrowband ultraviolet B (NB-UVB) for a total of 20-27 treatments. Epidermal samples were analysed using oligonucleotide microarrays. Our microarray results led us to explore further and to quantify a specific gene, insulin-like growth factor-binding protein-7 (IGFBP7), using real-time quantitative reverse transcriptase-polymerase chain reaction assays and immunohistochemical protein expression. We identified 315 genes modulated by phototherapy: the expressions of 248 genes (142 up; 106 down) were changed by Dead Sea treatment, 116 (71 up; 45 down) by NB-UVB and 49 (37 up; 12 down) were modulated regardless of treatment. The differentially changed genes include S100 calcium-binding proteins, dendritic cell markers, tumour necrosis factor-alpha target genes, matrix metalloproteinases and NFkappaB target genes. We also found that IGFBP7 mRNA and protein were significantly underexpressed in psoriatic compared with normal epidermis, and that phototherapy significantly increased their expression. IGFBP7 is underexpressed in psoriatic epidermis but is inducible by UVB.